HomeMy WebLinkAbout2014 CBJ - Biosolids Report CH2MFinal Report
Biosolids Treatment and Disposal Evaluation – Phase II
Prepared for City and Borough of Juneau
September, 2014
949 East 36th Avenue
Suite 500
Anchorage, AK 99508
WBG090414062923ANC III
Contents
Section Page
Executive Summary
1.1 Project Goals and Objectives Accomplished ........................................................................................... 1
1.2 Design and Evaluation Criteria ................................................................................................................ 1
1.3 Results of Alternatives Evaluation .......................................................................................................... 3
1.4 Recommended Operating Strategy ........................................................................................................ 6
1.5 Recommended Project Delivery Method ............................................................................................... 7
Tables
ES-1 Design Criteria for CBJ’s Solids Management Alternatives ..................................................................... 2
ES-2 Non-Monetary Criteria and Weightings Used in Alternatives Evaluation .............................................. 3
ES-3 Net Present Value (NPV) Cost Estimates of the Alternatives for MWWTP Facility Location ................. 5
ES-4 Net Present Value (NPV) Cost Estimates of the Alternatives for JDWWTP Facility Location ................. 5
ES-5 Anticipated Project Schedule under Option 1: Construction of Drying and Heat-Recovery
Systems in a Single Capital Project ......................................................................................................... 7
ES-6 Anticipated Project Schedule under Option 2: Construction of Drying and Heat-Recovery
Systems in a Single Capital Project using Progressive Design-Build Delivery Approach ......................... 8
Figures
ES-1 Stacked Bar Chart Display of Non-monetary Criteria Rankings of Alternatives 1-4 ............................... 4
ES-2 Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for MWWTP Facility Location . 5
ES-3 Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for JDWWTP Facility Location. 6
TM 1 - Data Review & Regulatory Conditions and Outlook
1.1 Introduction ............................................................................................................................................ 1
2.1 Summary of Information Received to Date ............................................................................................ 1
3.1 Review of Solids Production Data ........................................................................................................... 3
3.2 Review of Solids Characteristics and Analytical Results ......................................................................... 5
4.1 Review of Pertinent Federal Regulations ................................................................................................ 6
4.1.1 40 CFR Part 503 Subpart B: Land Application ............................................................................ 7
4.1.2 40 CFR Part 503 Subpart C: Surface Disposal ............................................................................. 8
4.1.3 40 CFR Part 503 Subpart D: Pathogen and Vector Attraction Reduction .................................. 9
4.1.4 40 CFR Part 503 Subpart E: Incineration .................................................................................. 11
4.2 Predicted Changes to Federal Part 503 Regulation and their Potential Impacts ................................. 11
5.1 Review of Pertinent State and Local Regulations ................................................................................. 12
5.1.1 State Disposal Regulations ....................................................................................................... 12
5.1.2 End Uses ................................................................................................................................... 13
5.1.3 State Air Regulations ................................................................................................................ 13
5.1.4 Local Requirements: ................................................................................................................ 14
6.1 Suggested Design Criteria for Biosolids Handling Facility ..................................................................... 15
6.1.1 Proposed Solids Projections ..................................................................................................... 15
7.1 Summary and Conclusions .................................................................................................................... 16
7.2 Path Forward......................................................................................................................................... 18
CONTENTS
IV WBG090414062923ANC
Tables
1 Summary of Documents and Historical Data provided by CBJ to CH2M HILL related to Biosolids
Study ....................................................................................................................................................... 2
2 2013 Solids Production from CBJ’s MWWTP and JDWWTP, plus Combined Totals .............................. 3
3 Comparison of EPA Part 503 Pollutant Ceiling Limits and “Exceptional Quality” Pollutant
Concentration Limits with Results of Recent Solids Analyses from JDWWTP and MWWTP ................. 5
4 Results of Other Constituents of Interest from Recent Solids Analyses from JDWWTP and MWWTP . 6
5 Pathogen Reduction Requirements from 40 CFR Part 503 Rule ............................................................ 9
6 Minor Air Permit Limits ........................................................................................................................ 14
7 Proposed General Design Criteria for Purpose of Developing Solids Management Alternatives ........ 15
Figures
1 Total Monthly Solids Production from CBJ’s MWWWTP and JDWWTP in 2013 .................................... 4
2 Evaluation Criteria and Weightings to be Used in Biosolids Alternatives Analysis .............................. 17
TM 2 - Alternatives Evaluation and Results
1.1 Introduction ............................................................................................................................................ 1
2.1 Solids Loading Projections, Characteristics, and Design Conditions ...................................................... 1
3.1 Description of Alternatives ..................................................................................................................... 3
Alternative 1 - Continuing the Transport and Landfilling of Dewatered Biosolids ................... 4
Alternative 2 - Thermal Drying Technology ............................................................................... 5
Alternative 3 - Thermal Drying followed by Incineration for Heat Recovery ............................ 6
Alternative 4 – New Fluidized Bed Incinerator .......................................................................... 9
4.1 Alternatives Evaluation .......................................................................................................................... 9
Review of Evaluation Criteria, Weighting, and Ranking ............................................................ 9
Carbon Footprint Estimates and Comparisons between Alternatives .................................... 10
Non-Monetary Comparison of Alternatives ............................................................................ 12
Methodology for Cost Estimation ........................................................................................... 12
Cost Comparison of Alternatives ............................................................................................. 14
Benefit-cost Comparison of Alternatives ................................................................................ 14
5.1 Recommended Alternative .................................................................................................................. 15
Tables
1 Proposed General Design Criteria for Purpose of Developing Solids Management Alternatives .......... 2
2 Selected Results from Ultimate & Proximate Analysis of Solids from JDWWTP and MWWTP ............. 3
3 Summary of CBJ Biosolids Disposal Amounts in Wet Tons (WT) in Calendar Year (CY) 2013 ................ 5
4 Results of Developing and Weighting Non-Monetary Criteria Used in Alternatives Evaluation ......... 10
5 Estimated Annual Greenhouse Gas (GHG) Emissions (Carbon Footprint) of Each Alternative ........... 11
6 Results of Developing and Weighting Non-Monetary Criteria Used in Alternatives Evaluation ......... 12
7 CBJ Reference Unit Costs ...................................................................................................................... 13
8 Capital Cost Breakdown of Alternatives for MWWTP Facility Location ............................................... 16
9 Capital Cost Breakdown of Alternatives for JDWWTP Facility Location............................................... 17
10 Annual O&M Cost Breakdown of Alternatives for MWWTP Facility Location ..................................... 18
11 Annual O&M Cost Breakdown of Alternatives for JDWWTP Facility Location ..................................... 18
12 Net Present Value (NPV) Cost Estimates of the Alternatives for MWWTP Facility Location ............... 19
13 Net Present Value (NPV) Cost Estimates of the Alternatives for JDWWTP Facility Location ............... 19
14 Benefit-cost Score of Alternatives for MWWTP Location .................................................................... 20
15 Benefit-cost Score of Alternatives for JDWWTP Location .................................................................... 20
CONTENTS
WBG090414062923ANC V
Figures
1 Belt Drying Process Schematic ................................................................................................................ 7
2 Dried Biosolids Product from a Belt Dryer (courtesy of Kruger) ............................................................. 7
3 BioCon Dryer and Energy Recovery System (BioCon-ERS) Process ........................................................ 8
4 BioCon-ERS Incinerator Furnace ............................................................................................................. 8
5 Typical Fluidized Bed Incinerator (FBI) and Accessories ......................................................................... 9
6 Stacked Bar Chart Display of Non-monetary Criteria Rankings of Alternatives 1-4 ............................. 13
7 Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for
MWWTP Facility Location ..................................................................................................................... 19
8 Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for
JDWWTP Facility Location ..................................................................................................................... 20
9 Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for MWWTP Facility
Location ................................................................................................................................................. 21
10 Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for JDWWTP Facility
Location ................................................................................................................................................. 21
TM 3 - Long Term Plan and Operating Strategies
1.1 Introduction ............................................................................................................................................ 1
2.1 Recommended Alternative ..................................................................................................................... 1
Results of Alternative Evaluation Workshop ............................................................................. 1
Description of Recommended Alternative ................................................................................ 4
Planning and Siting Recommendations ..................................................................................... 6
3.1 Recommended Operating Strategies ...................................................................................................... 9
Operating Strategies at Similar Facilities ................................................................................... 9
Recommended Operating Strategies for CBJ ........................................................................... 11
4.1 Project Phasing and Scheduling Options .............................................................................................. 12
Anticipated Project Schedules under Two Delivery Options ................................................... 12
Recommended Next Steps ....................................................................................................... 13
Tables
1 Advantages/Disadvantages of Biosolids Facility Location ...................................................................... 7
2 Summary of Operating Belt Drying Facilities in the USA (dryers manufactured by Kruger) ................ 10
3 Anticipated Project Schedule under Option 1: Construction of Drying and Heat-Recovery
Systems in a Single Capital Project ....................................................................................................... 12
4 Anticipated Project Schedule under Option 2: Construction of Drying and Heat-Recovery
Systems in a Single Capital Project using Progressive Design-Build Delivery Approach ....................... 13
Figures
1 Benefit-Cost Scores of Alternatives 1-4 with Biosolids Management Facility at MWWTP .................... 2
2 Benefit-Cost Scores of Alternatives 1-4 with Biosolids Management Facility at JDWWTP .................... 2
3 Comparison of NPW (Capital and O&M Cost Components) among Alternatives 1-4 with Biosolids
Management Facility at MWWTP ........................................................................................................... 3
4 Comparison of NPW (Capital and O&M Cost Components) among Alternatives 1-4 with Biosolids
Management Facility at JDWWTP ........................................................................................................... 3
5 Belt Dryer Schematic Diagram ................................................................................................................ 5
6 Simplified schematic Diagram of Alternative 3 – Thermal Drying with Energy Recovery Furnace,
Based on Kruger BioCon-ERS Model ....................................................................................................... 6
7 Potential Location of Thermal Dryer with Energy Recovery Furnace at the JDWWTP Site .................... 8
8 Potential Location of Thermal Dryer with Energy Recovery Furnace at the MWWTP Site .................... 9
9 General Arrangement Drawing of Thermal Dryer with Energy Recovery Furnace ............................... 10
WBG090414062923ANC 1
Final Report
Biosolids Treatment and Disposal Evaluation – Phase II
Executive Summary
PREPARED FOR: City/Borough of Juneau (CBJ), Alaska
PREPARED BY: CH2M HILL
DATE: September 2, 2014
1.1 Project Goals and Objectives Accomplished
The City/Borough of Juneau’s (CBJ’s) Biosolids Treatment and Disposal Evaluation has built upon recent
investigations by CBJ into possible disposal and treatment alternatives for the waste biosolids produced at CBJ’s
Juneau-Douglas Wastewater Treatment Plant (JDWWTP) and Mendenhall Wastewater Treatment Plant
(MWWTP). The following objectives were completed as part of this project and are described in the three
Technical Memorandums (TMs) that form the body of this report:
1. Pertinent data and information provided by CBJ related to recent and current biosolids production and
disposal practices were reviewed and summarized (TM1).
2. Federal, state, and local regulations, were also reviewed and summarized, providing a regulatory outlook for
CBJ’s future biosolids use or disposal options (TM1).
3. Design criteria were developed for the analysis of biosolids management alternatives for CBJ, based on
historical records and population projections (TM2).
4. Evaluation criteria for the alternatives evaluation were developed and weighted by the project team (TM2).
5. Potential alternatives for long-term biosolids management evaluation were screened and narrowed down to
three new alternatives, in addition to the alternative of continuing current biosolids management practices,
for more detailed evaluation (TM2).
6. The results of the alternatives evaluation were reviewed and discussed in a project workshop, and then one
alternative was selected for implementation: a belt-driven thermal dryer with energy-recovery furnace (TM2).
7. An implementation plan with recommended operating strategies, delivery options, and schedules was
developed (TM3).
1.2 Design and Evaluation Criteria
Based on a review of historical conditions and projections of future conditions for the CBJ, Table ES-1 presents
design solids-loading criteria developed for biosolids management facilities at the JDWWTP and the MWWTP,
(which includes the Auke Bay WWTP solids), and combined loadings from both facilities. The units describing
biosolids quantity are in dry tons per day (DT/day) and wet tons per day (WT/day). The projected loadings are
based on historical trends summarized in the Phase 1 report, supplemented by data from calendar year 2013.
Population projections do not predict any significant growth of the CBJ’s service area in the next 20 years. CBJ
decided, however, to add 10% reserve capacity to current solids loading estimates to account for the potential of
increased industrial activity and population growth in the future.
Belt filter presses at both WWTPs produced an average of 15.8% solids in 2013, but WWTP production records
show that dewatered cake solids range from 14% to 17% solids on a day-to-day basis. For sizing of future biosolids
handling facilities, it is conservatively assumed that dewatering facilities at both WWTPs will produce 15% Total
Solids (TS). If the dewatering operations can produce solids of higher TS content than 15% TS in the future, then
the future biosolids handling facilities will have additional reserve capacity, which will provide for more
redundancy and flexibility in operations.
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
2 WBG090414062923ANC
TABLE ES‐1
Design Criteria for CBJ’s Solids Management Alternatives
Design Criterion
JDWWTP
Solids MWWTP Solids
Combined
Solids Remarks
Average Annual
Solids Loading
0.8 DT/day 2.6 DT/day 3.4 DT/day Annual average loadings are used for
estimating O&M costs
Average Annual
Solids
Concentration
15% TS 15% TS 15% TS It is assumed that existing solids dewatering
capability can be maintained, but not
improved. Even though 15.8% TS was
achieved in 2013, 15% TS is assumed for
conservatism in design.
Average Annual
Solids Loading,
WT/day
5.3 WT/day 17.3 WT/day 22.6 WT/day This is the mathematical result of dry solids
loadings divided by %solids fraction.
Maximum
Month/Average Day
Peaking Factor
1.5 1.3 1.35 Slightly more conservative than existing
peak factors.
Maximum Month
Solids Loading,
DT/day
1.2 DT/day 3.4 DT/day 4.6 DT/day Monthly maximum daily values are assumed
for design with sufficient liquid storage
capacity to handle daily and weekly peak
loadings.
Maximum Month
Solids Loading,
WT/day
8.0 WT/day 22.7 WT/day 30.7 WT/day The maximum month, average daily
biosolids production rates in WT/day govern
sizing of drying and incineration equipment.
Biosolids samples taken during the study indicate that levels of metals are safe and well below EPA limits. Odors
and pathogen indicators typically found in untreated biosolids can be reduced by appropriate treatment. There
are a number of technologies that can convert biosolids to topsoil amendments or low‐grade fertilizers, but there
does not appear to be sufficient market demand in Juneau to use these products, so CBJ’s primary drivers for
biosolids management are volume reduction to reduce disposal costs and odor reduction to minimize impacts on
the public.
The Juneau area poses some unique geographical challenges that point toward a general need for more
established and reliable technologies. These challenges include a relatively remote location, limited
transportation options that may result in delayed shipments for equipment, an unpredictable climate, and lack of
specialized support services. Considering these factors, project team members agreed that the responsible choice
for CBJ is to settle on an established or innovative technology (according to the Environmental Protection
Agency’s [EPA’s] definitions for established, innovative, and embryonic technologies) that can demonstrate a
successful track record of operating facilities.
The project team agreed upon the following three governing principles for selecting a biosolids management
alternative:
1. Need Class A pathogen reduction to create an “exceptional quality” biosolids
2. Need to have multiple options for end use to minimize risk of disposal
3. Need to maximize volume reduction to the extent possible.
Based on these governing principals, the following three alternatives were selected for more detailed analysis:
1. Thermal dryer with production of Class A biosolids
2. Dryer with energy‐recovery furnace
3. Stand‐alone incinerator (fluidized bed type)
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
WBG090414062923ANC 3
Table ES-2 shows the evaluation criteria and weightings developed by the project team for alternatives analysis.
The criteria weights were assigned based on a prioritization exercise completed by the team at Workshop 1 and
refined in Workshop 2. The alternatives were then scored against those criteria based on a high probability of
meeting or exceeding current and future needs (high score) or low probability of meeting or exceeding current
and future needs (low score).
TABLE ES-2
Non-Monetary Criteria and Weightings Used in Alternatives Evaluation
Criteria
No.
Evaluation
Criteria
Criteria
Weights Criteria Descriptions
1 Ease of operation 9.1 Relative ease of operating the technologies involved in each alternative, compared to
existing operations. Technologies considered easier to operate receive higher score.
2 Carbon footprint 3.6 An estimate of the amount of greenhouse gas (GHG) emissions that would be emitted as a
result of implementing each of the alternatives. Lower GHG emissions receive higher score.
3 Timeline for
implementation
14.5 Estimated time required to implement each alternative, relative to other alternatives.
Alternatives with faster timeline receive higher score.
4 Location of the
technology
1.8 Flexibility to locate the facilities involved in each alternative at any one of three possible
locations (JDWWTP, MWWTP, and Capitol Landfill) relative to other alternatives.
Alternatives with greater location flexibility receive higher score.
5 Logistics of
transport
7.3 Ease or difficulty in which end product from each alternative (dewatered cake, dried solids,
or ash) can be transported, relative to other alternatives. Alternatives with end products
considered easier to transport receive higher score.
6 Public health &
safety issues
18.2 Possibility of each alternative to create public health or safety issues relative to the other
alternatives. Greater possibility of creating issues results in lower score.
7 Environmental &
permitting issues
7.3 Likelihood of each alternative to encounter environmental or permitting problems, relative
to the other alternatives. Higher likelihood of problems results in lower score.
8 Risk 16.4 The amount of risk associated with implementing each alternative, from the perspectives
of new technology, process complexity, and possibility of failure during operations, relative
to the other alternatives. Alternatives with higher risk receive lower score.
9 End product
disposal method
10.9 Likelihood of each alternative to experience ease or difficulty with end product disposal.
Greater anticipated difficulty results in lower score.
10 Energy
consumption &
sourcing
10.9 Estimated amount of energy and source of energy required by each alternative compared
with the other alternatives. Higher score to alternatives with lower energy requirements
and higher scores to alternatives that can create energy or use local energy sources.
Total Weight 100.0
1.3 Results of Alternatives Evaluation
The alternatives for biosolids management selected by the CBJ for detailed evaluation were:
1. Continuation of the current practice of shipping dewatered biosolids from the JDWWTP and the MWWTP by
barge to Oregon for landfill disposal (also known as the “status quo” or “base case” alternative).
2. Thermal drying of biosolids at a central facility with local disposal or marketing of the dried, Class A biosolids
product.
3. Thermal drying of biosolids followed by combustion of the biosolids in a furnace to recover heat that is then
recirculated to the biosolids drying process, thus reducing the amount of purchased fuel.
4. Thermal combustion (incineration) of the biosolids in a new fluidized-bed incinerator that recovers heat from
the combusted biosolids to aid in evaporation and reduce the amount of purchased fuel.
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
4 WBG090414062923ANC
Figure ES-1 presents in bar chart format the results of the non-monetary evaluation using the criteria and
weightings described above:
FIGURE ES-1
Stacked Bar Chart Display of Non-monetary Criteria Rankings of Alternatives 1-4
As shown in Figure ES-1, Alternative 3 (Dryer and Heat-Recovery Furnace), ranked highest in non-monetary terms.
Alternative 2 (Thermal Drying) and Alternative 4 (Incineration) tied for next highest ranking. Alternative 1
(Continued Status Quo of Landfill Disposal) ranked lowest in non-monetary terms.
Cost estimates including capital costs, annual operation and maintenance (O&M) costs, and net present value,
were also developed. All costs were derived using the same level of estimating accuracy so the cost estimates for
the four alternatives are comparable. Actual construction costs may differ from the estimates presented,
depending on specific design requirements and the economic climate at the time a project is bid. The American
Association of Cost Engineers (AACE) has developed levels of accuracy for various stages of construction cost
estimation. The estimates produced for the current comparison are Class 5, with a corresponding project
definition level of 0-2% and expected level of accuracy of 20-50% below and 30-100% above the cost given.
The cost estimates for each alternative varied depending on whether biosolids processing is centralized at the
MWWTP or JDWWTP, as summarized in Tables ES-3 and ES-4.
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Cumulative Criteria ScoresProjects
Ranking of Alternatives
by Total Benefit Value
Ease of operation Carbon Footprint Timeline for implementation
Location of the technology Logistics of transport Public health & safety issues
Environmental & permitting issues Risk End product disposal method
Energy consumption and sourcing
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
WBG090414062923ANC 5
TABLE ES-3
Net Present Value (NPV) Cost Estimates of the Alternatives for MWWTP Facility Location
Alternative
Number Name of Alternative
NPV of Capital
Cost
NPV of Annual
O&M Costs Total NPV
1 Maintain Status Quo $2,700,000 $32,200,000 $34,900,000
2 Thermal Drying $18,300,000 $16,100,000 $34,400,000
3 Thermal Drying with Heat-Recovery Furnace $26,600,000 $9,400,000 $36,000,000
4 Thermal Oxidation (Incineration) $50,200,000 $10,900,000 $61,100,000
TABLE ES-4
Net Present Value (NPV) Cost Estimates of the Alternatives for JDWWTP Facility Location
Alternative
Number Name of Alternative
NPV of Capital
Cost
NPV of Annual
O&M Costs Total NPV
1 Maintain Status Quo $2,700,000 $32,200,000 $34,900,000
2 Thermal Drying $19,500,000 $17,500,000 $37,000,000
3 Thermal Drying with Heat-Recovery Furnace $27,900,000 $10,700,000 $38,600,000
4 Thermal Oxidation (Incineration) $51,500,000 $12,300,000 $63,800,000
The non-monetary criteria were then combined with the total costs to produce a Benefit-Cost score. In this
evaluation, following the traditional procedure for Benefit/Cost evaluations, the total non-monetary scores were
assigned a 50% weighting and the NPV scores were assigned the remaining 50% weighting in computing the
Benefit/Cost scores of each alternative. As with the O&M and capital cost comparisons, each of the new
alternatives is shown as having a higher or lower benefit-cost score than the Status Quo alternative, which is
assigned a 100% baseline score.
Figures ES-2 and ES-3 depict the relative Benefit/Cost scores of each alternative in bar chart format.
FIGURE ES-2
Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for MWWTP Facility Location
100%
129%129%
73%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
6 WBG090414062923ANC
FIGURE ES-3
Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for JDWWTP Facility Location
If CBJ has sufficient capital funds to pay for the slightly higher capital cost of Alternative 3, then substantial annual
savings can be achieved by reduction of O&M costs associated with Alternative 3. Also, if an opportunity exists to
defray the capital costs through grant funding, Alternative 3 would be the most desirable alternative to
implement in monetary terms, because the investment in higher capital for Alternative 3 would substantially
reduce CBJ’s annual O&M costs. Alternative 3 also scored highest in the non-monetary evaluation; therefore,
Alternative 3 – Thermal Drying with Heat-Recovery Furnace (energy recovery system) is the recommended
alternative for implementation.
1.4 Recommended Operating Strategy
There are two potential site locations for CBJ’s biosolids drying facility, the MWWTP or the JDWWTP. The
MWWTP produces almost 80% of CBJ’s biosolids, so would be the logical choice for siting a central biosolids
management facility to reduce the extent of biosolids hauling. However, the site at MWWTP is more constrained,
and the Mendenhall Valley where the MWWTP is located is currently a non-attainment area for air emissions,
which would likely increase the cost of permitting and air-emissions technology at the MWWTP. The JDWWTP site
has more available space and a wider buffer from its adjacent properties, and is not as sensitive as the MWWTP
site with respect to its air-permitting requirements.
Based on CH2M HILL’s recent phone and email survey of other belt dryers operating in the USA, it is
recommended that CBJ plan to operate its belt dryer and heat-recovery furnace around-the-clock when it has
sufficient solids inventory. Both the JDWWTP and MWWTP appear to have sufficient pre-dewatering solids
storage capacity, although the JDWWTP has more storage volume in its aerobic digestion basin than the MWWTP
has in its settled-solids holding tank.
It does not appear that CBJ would need to have staff onsite around-the-clock to oversee operation of a
drying/heat recovery facility. Similar to several other belt drying facilities in the U.S., unattended operation of the
dewatering and drying systems would be possible, provided that system monitoring can be done remotely via
internet or telephone. Control systems for CBJ’s thermal drying facilities would need to be designed with special
features for remote operation.
Transport of dewatered biosolids will be required from one of the WWTPs to the other WWTP where the thermal
drying facilities are located. It is recommended that truck hauling be done at night to decrease hauling time, and
minimize the potential for traffic problems and odor complaints.
100%
120%120%
70%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
WBG090414062923ANC 7
1.5 Recommended Project Delivery Method
It is recommended that the project be implemented and phased under one of the following two methods:
1. Design of belt drying system and heat-recovery furnace in a single capital project using a traditional design-
bid-build approach.
2. Construction of drying and heat-recovery systems in a single capital project using progressive design-build
delivery approach
Table ES-5 presents a general project schedule under the Option 1 scenario above, in which the belt drying system
and heat-recovery system would be designed and installed together as part of the same capital project.
TABLE ES-5
Anticipated Project Schedule under Option 1: Construction of Drying and Heat-Recovery Systems in a Single Capital Project
Activity
Year 2014 2015 2016 2017
Quarter 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd
Preliminary Engineering
Project Funding*
Design & Permitting
Dryer/Furnace Procurement & Submittals
Dryer/Furnace Manufacturing & Delivery*
Bidding and Construction**
Startup**
Full-scale Operations
*The dryer/furnace manufacturing/deliver and construction schedule are tied to project funding availability.
**Construction phase ends at substantial completion; final completion would occur after successful startup.
It may be possible to accelerate the schedules shown in Table ES-5 by up to six months using an alternative
delivery method such as progressive design-build or construction management at-risk. Under progressive design-
build delivery, for example, the project schedule would be compressed in the design and construction phases,
since those phases would be delivered by the Design-Build Contractor. An anticipated project schedule under
progressive design-build delivery is shown in Table ES-6.
There are a number of challenges related to utilizing an alternative approach other than traditional design-bid-
build in Alaska. Very few if any public utilities in Alaska have used alternative delivery methods on projects of
significant size. Also, a Certificate to Construct is required prior to beginning construction of a water or
wastewater facility in Alaska. To get the Certificate to Construct, design documents must be submitted to ADEC
for plan review at the 95% completion level. Plan review times by ADEC are not predictable and with a relatively
new technology, could be protracted.
Even though Table ES-6 shows the potential for saving 3-6 months on the project schedule with an alternative
delivery approach, the time requirement for ADEC review of 95% design documents prior to construction may
negate any potential time savings under a design-build approach.
BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II EXECUTIVE SUMMARY
8 WBG090414062923ANC
TABLE ES-6
Anticipated Project Schedule under Option 2: Construction of Drying and Heat-Recovery Systems in a Single
Capital Project using Progressive Design-Build Delivery Approach
Activity
Year 2014 2015 2016 2017
Quarter 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd
Preliminary Engineering
Project Funding & DB Contractor Selection*
Design, Permitting, and Construction**
Dryer/Furnace Procurement & Submittals
Dryer/Furnace Manufacturing & Delivery*
Startup**
Full-scale Operations
*The dryer/furnace manufacturing/deliver and construction schedule are tied to project funding availability.
**Construction phase ends at substantial completion; final completion would occur after successful startup.
Therefore, it is recommended that CBJ plan to implement the project using the more traditional, design-bid-build
approach as shown in Table ES-5, which is more predictable and will reduce the possibility of unexpected delays.
Preliminary engineering would need to get underway in the last quarter of 2014 and be completed in the first
quarter of 2015, and project funding would need to be identified by early 2015, for the project to proceed on
schedule and begin construction by early 2016, then have an operational biosolids-drying facility by late 2016 or
early 2017.
Discussions and decisions regarding the project funding and delivery method would need to occur during the
preliminary engineering phase, at which point one of the delivery options described above will be chosen, along
with the preferred project funding mechanism, which will include exploration of alternatives to defray project
capital costs through grants and low-interest loans.
WBG090414062923ANC 1
TECHNICAL MEMORANDUM 1
Biosolids Treatment and Disposal Evaluation – Phase II Data Review & Regulatory Conditions and Outlook
PREPARED FOR: City/Borough of Juneau (CBJ), Alaska
PREPARED BY: CH2M HILL
DATE: July 8, 2014
1.1 Introduction
The purpose of this technical memorandum (TM) is two-fold:
1. To summarize CH2M HILL’s review of data and information provided by City/Borough of Juneau (CBJ)
regarding production and characteristics of waste activated solids, hereinafter referred to as “solids,” or
“biosolids.”
2. To summarize federal, state, and local regulations and to provide a regulatory outlook pertinent to CBJ’s
future biosolids use or disposal options.
This TM updates information provided in the prior Biosolids Management System Alternatives Study, dated
April 1, 2013, which was conducted for CBJ and is referred to herein as the Phase 1 Biosolids Report.
Information from the Phase 1 Biosolids Report will not be repeated in this TM unless it is necessary to
provide context to the updated information. When necessary for the project record, some information from
the Phase 1 Biosolids Report may be corrected and updated in this TM.
2.1 Summary of Information Received to Date
Table 1 lists relevant documents and information that CBJ has provided to CH2M HILL since the project
began through the date of this TM.
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TABLE 1
Summary of Documents and Historical Data provided by CBJ to CH2M HILL related to Biosolids Study
Brief Description of Data or Document Data or Document Source, Date, and Comments
Biosolids Management System Alternatives Study By Tetra Tech, dated April 2013
2010 Biosolids Metals Analyses Received, but not in useable format. Requested additional
analyses.
Drawings by Carson Dorn for JDWWTP Incinerator
Improvements
Received in PDF format, dated 2010. Some cost estimates
also provided by email
Memo from Lammergeier CleanTech to CBJ about supercritical
water oxidation (SWO) system
Received via email, dated May 2012
MWWTP Power Bill for Sept. 2013 Received as PDF attachment to email
CBJ Request for Bids – Biosolids Disposal Services Nov.-Dec. 2013; project was cancelled
TM on Fats, Oils & Grease (FOGs) by Tetra Tech Dated May 2013, received from CBJ via email
Email from Robert Deering of April 1, 2014 to CBJ about
Genifuel technology
Received via email from CBJ
Dec. 2013 Letter from Ecological Engineering Group to CBJ
proposing anaerobic co-digestion
Received via email from CBJ
Email from Robert Deering of April 1, 2014 to CBJ about
gasification project in Covington, TN by PHG Energy
Received via email from CBJ
TM on Incorporating Aerobic Digestion with Membrane
Thickening into Other Treatment and Disposal Options
By Tetra Tech dated, 11/29/13
TM on Pretreatment for Aerobic Digestion/Membrane
Thickening Process at MWWTP
By Tetra Tech dated, 12/2/13
Descriptive List of Biosolids Treatment Alternatives for CBJ,
including Incineration, ATAD, Composting, and Drying
By Tetra Tech, dated 9/19/13
Same List of Alternatives noted above, except in Matrix Format By Tetra Tech, dated 9/23/13
Monthly Operating Reports for MWWTP and JDWWTP Provided by CBJ
NPDES Permits for ABWWTP, JDWWTP, and MWWTP From CBJ website
CBJ 2008 Comprehensive Plan and 2014 & 2015 Capital
Improvement Plans
From CBJ website
Aerial Photos and Site Plans of JDWWTP and MWWTP Provided by CBJ
Air Emissions Permit and Correspondence for JDWWTP
Incinerator
Provided by CBJ
Information on Supply and Price of Wood Pellets as Heating Fuel Emailed by CBJ, June 2-3, 2014
TM 1: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION – PHASE II DATA REVIEW & REGULATORY CONDITIONS AND OUTLOOK
WBG090414062923ANC 3
3.1 Review of Solids Production Data
The CBJ owns and operates the following three wastewater treatment plants (WWTPs):
1. Auke Bay WWTP (ABWWTP), a facility where waste activated solids are stored aerobically and trucked
to the MWWTP (see below). The ABWWTP has a permitted treatment capacity of 0.16 million gallons
per day (MGD), expressed as a maximum daily limit.
2. Mendenhall WWTP (MWWTP), located north of downtown Juneau near the mouth of the Mendenhall
River. Waste activated solids from MWWTP are not digested. Solids from ABWWTP are combined with
MWWTP solids at the MWWTP and dewatered by belt filter press to approximately 15% total solids (TS).
The MWWTP has a permitted treatment capacity of 4.9 million gallons per day (MGD), expressed as a
maximum daily flow. No monthly average flow capacity is specified.
3. Juneau-Douglas WWTP (JDWWTP), located south of downtown Juneau near the Rock Dump Industrial
Area and barge lines terminal. Waste activated solids from JDWWTP are aerobically digested and
dewatered by belt filter press to approximately 15% TS. The JDWWTP has a permitted capacity of 2.76
MGD expressed as a maximum-month daily average, and 6.0 MGD expressed as a maximum daily flow.
As noted above, solids are generated only from the MWWTP and the JDWWTP. In order to update the
information on solids production that was provided in the Phase 1 Biosolids Report, CH2M HILL examined
monthly operating reports from MDWWTP and JDWWTP for calendar year 2013. Table 2 shows the solids
production rates from the MWWTP, JDWWTP, and combined solids production, for the calendar year 2013.
TABLE 2
2013 Solids Production from CBJ’s MWWTP and JDWWTP, plus Combined Totals
Solids Source: MWWTP JDWWTP Combined Solids
Month Wet Tons
Dry
Tons
Wet
Tons
Dry
Tons
Wet
Tons Dry Tons
Jan 526 58 0 0 526 58
Feb 518 56 180 27 697 82
Mar 425 83 217 27 642 109
Apr 485 59 126 17 611 77
May 457 76 199 33 657 109
Jun 386 66 152 26 539 92
Jul 425 58 152 27 577 85
Aug 455 75 155 27 610 102
Sep 377 75 147 26 524 101
Oct 536 68 166 25 702 92
Nov 356 86 86 13 442 99
Dec 371 82 94 16 465 99
Annual Totals: 5318 840 1675 264 6993 1105
Annual Average Day Rate (tons/day) 14.6 2.3 4.6 0.72 19.2 3.0
Maximum Month Average Day Rate (tons/day) 17.2 2.9 7.0 1.1 22.6 3.5
Maximum Month/ Average Day Peaking Factor 1.2 1.3 1.5 1.4 1.2 1.2
Annual Average %TS 15.8% 15.8% 15.8%
The capabilities of the belt filter presses used for solids dewatering are similar at the MWWTP and JDWWTP,
and each facility produced solids averaging 15.8% TS in 2013. Closer review of operating records shows
dewatering performance at both WWTPs ranging from 14% to 17% TS on a daily basis.
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The peaking factors of maximum month to average daily solids production are higher at the JDWWTP than
at the MWWTP, but that is largely because no solids dewatering was performed at the JDWTTP in January
and early February 2013, resulting in a backlog of solids that had to be dewatered in late February and
March at the JDWWTP.
Solids production from both WWTPs combined shows more consistency and lower peaks than solids
produced from each WWTP individually. Conversations with CBJ staff indicated that is partially due to the
transport of solids from one WWTP to another on occasions of equipment outages and other operational
issues.
The average daily biosolids production rates for 2013 are in line with average daily rates for 2012 as shown
in the Phase 1 Biosolids Report. A combined daily average of 18.5 wet tons per day (WT/day) and 2.8 dry
tons per day (DT/day) were reported for 2012, as compared with a combined daily average of 19.2 WT/day
and 3.0 DT/day for 2013 as shown above.
Figure 1 depicts combined solids production from CBJ’s JDWWTP and MWWTP in 2013, shown in bar chart
format as wet tons and dry tons for each month of the year.
FIGURE 1
Total Monthly Solids Production from CBJ’s MWWWTP and JDWWTP in 2013
Figure 1 shows that monthly solids production (similar to monthly wastewater flows) did not vary
considerably over the course of the year in 2013. Based on review of the 2013 biosolids data and the Phase
1 report, it is concluded for planning purposes that a traditional peaking factor of 1.35 can be applied to the
annual average to derive the maximum monthly loadings.
Altogether, 2013 was a typical year in terms of solids production rates and trends, as compared with prior
data from the Phase 1 Biosolids Report and confirmed by CBJ staff, thereby establishing a baseline for solids
projections.
0
100
200
300
400
500
600
700
800
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Wet Tons
Dry Tons
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WBG090414062923ANC 5
3.2 Review of Solids Characteristics and Analytical Results
Review of the Phase 1 Biosolids Report indicates that historical laboratory analyses of biosolids were not
analyzed or reported in terms useful for comparison with the EPA Part 503 Rule that governs biosolids use
and disposal. Therefore, new analyses were ordered as part of the current study. The first set of results were
from samples taken at the JDWWTP and MWWTP on May 14, 2014, with results reported on May 29, 2014.
The results are summarized and compared with EPA Part 503 pollutant ceiling limits in Table 3.
The results shown in Table 3 indicate that the regulated pollutants in dewatered biosolids from JDWWTP
and MWWTP are all safely below the limits stipulated in the EPA Part 503 Rule, typically by an order of
magnitude. While these grab samples are not necessarily representative of biosolids quality throughout the
year, the low levels of regulated pollutants indicate that there should not be any issues with beneficial use
or disposal of CBJ’s biosolids with respect to presence of these regulated constituents.
TABLE 3
Comparison of EPA Part 503 Pollutant Ceiling Limits and “Exceptional Quality” Pollutant Concentration Limits
with Results of Recent Solids Analyses from JDWWTP and MWWTP
Pollutant
EPA Part 503 Subpart B
Pollutant Ceiling
Concentrations
(mg/kg)1
EPA Part 503 Subpart B
Pollutant Concentrations for
Exceptional Quality Biosolids
(mg/kg)1,2
JDWWTP Sample
Results3
MWWTP Sample
Results3
Arsenic 75 41 6.9 4.5
Cadmium 85 39 1.7 < 1.0
Chromium NA NA 14 6.3
Copper 4,300 1,500 520 280
Lead 840 300 20 7.6
Mercury 57 17 1.1 <1.0
Molybdenum 75 TBD 6.6 2.2
Nickel 420 420 11 3.7
Selenium 100 36 4.9 2.9
Zinc 7,500 2,800 580 390
1 Source: Subpart B, Part 503 Regulation. All values are on a dry weight basis. Applies to all biosolids to be land-applied.
2 Applies to biosolids sold or given away in bag or other container for land application, also representing the exceptional quality or
“clean sludge” limits.
3 Dewatered biosolids cake sampled on May 14, 2014, and analyses reported on May 29, 2014.
mg/kg = milligrams per kilogram; NA = not applicable (prior standards were legally challenged)
The dewatered biosolids samples that were taken from the MWWTP and JDWWTP on May 14, 2014, were
analyzed for a number of other constituents in addition to the regulated pollutants shown in Table 3.
Additional results related to constituents of interest for beneficial use and disposal options are shown in
Table 4 with brief remarks regarding the importance of each constituent shown.
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TABLE 4
Results of Other Constituents of Interest from Recent Solids Analyses from JDWWTP and MWWTP
Constituent
JDWWTP
Sample
Results1
MWWTP
Sample
Results1 Remarks
Total Solids (TS) 14% 16% Expressed as % of total mass, the remainder being water; shows
better dewatering at MWWTP than at JDWWTP
Volatile Solids
(Organic Matter)
82.4% 90.0% Expressed as % of total solids above, volatile solids are a sign of fuel
value and relative biological stability. Both samples show relatively
high fuel value; MWWTP solids are not digested and so have higher
fuel value and lower stability
Ash Content 17.6% 10.0% Ash is the remaining dry matter that is not volatile and consists
primarily of nutrients, silica, and metals
Total Nitrogen 7.8% 8.1% Expressed as % of total dry mass, nitrogen levels are relatively high,
showing good fertilizer value
Ammonia
Nitrogen, mg/kg
980 3900 Higher ammonia in cake from MWWTP indicates lower stability and
that biosolids were not digested
Nitrate, mg/kg 9.0 < 1.0 Higher nitrate in cake from JDWWTP indicates that solids were
aerobically digested prior to dewatering
Phosphorus (as
Phosphate)
4.3% 3.6% Relatively high in phosphorus emphasizing good fertilizer value
pH units 6.56 5.94 Both pH results are within expected ranges but slightly acidic.
MWWTP is more acidic showing fermentation of the undigested solids
1 Dewatered biosolids cake sampled on May 14, 2014, and analyses reported on May 29, 2014.
As noted in Table 4, results from these two samples show characteristics reflective of national trends for
biosolids that are (1) aerobically digested, in the case of JDWWTP and (2) undigested, in the case of
MWWTP. The total solids (TS) concentration was noticeably higher in the MWWTP sample (16% TS)
compared with the JDWWTP sample (14% TS). This may be because undigested solids are usually easier to
dewater than digested solids; however, total dry solids for 2013 averaged 15.8% at both JDWWTP and
MWWTP, so the differences in dewatering characteristics between solids from the two WWTPs may be
inconsequential. Volatile solids (organic matter) were higher in the undigested sample from MWWTP at
90%, but also relatively high from JDWWTP at 82.4%. High volatile solids are an indicator of higher
combustibility, and the laboratory results of ultimate and proximate analysis from Hazen Labs have
confirmed the higher fuel value of MWWTP solids (received later and summarized in TM2). The difference in
volatile solids content of biosolids from the JDWWTP and MWWTP are also reflected in the ash contents of
the two WWTP solids, where the JDWWTP solids have a higher ash content than MWWTP solids because
JDWWTP solids have been partially digested.
Finally, values of the primary nutrients, nitrogen and phosphorus, were relatively high in both samples, so
heat-dried solids from these two WWTPs would be expected to have good fertilizer potential. In summary,
both samples reflect typical values for waste-activated solids from municipal WWTPs. The differences
between CBJ’s two WWTPs shown in Table 4 are mostly attributable to the partially digested nature of
JDWWTP solids, compared with the undigested nature of MWWTP solids.
4.1 Review of Pertinent Federal Regulations
When biosolids are prepared to be applied to the land, placed in a surface disposal site, or incinerated, the
person who performs such preparation must meet the applicable requirements specified in pertinent EPA
regulations, most of which are codified under 40 CFR Part 503 (Part 503 Rule). This preparer could be the
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WBG090414062923ANC 7
individual who generates biosolids during the treatment of domestic wastewater or the individual who
derives a material from biosolids. The latter would include, for example, the individual who blends biosolids
with some other material or a private contractor who receives biosolids from a treatment works and then
blends the biosolids with some other material (e.g., a bulking agent).
The record keeping and reporting requirements of the Part 503 Rule specify who must develop and retain
information, what information must be developed and the length of time such information must be kept.
Section 405(f) of the Clean Water Act (CWA) provides that permits issued to a publicly owned treatment
works (POTW) or any treatment works treating domestic sewage shall include conditions to implement the
Part 503 Regulation unless such are included in permits issued under other federal or approved state
programs.
However, it should be noted that the requirements in the Part 503 Rule must be met even in the absence of
a permit, i.e., the Part 503 Rule is self-implementing. Thus, a responsible person must become aware of the
Part 503 standards, comply with them, perform appropriate monitoring and record keeping and, if
applicable, report information to the permitting authority even when a permit is not issued. These standards
are also directly enforceable against any individual who uses or disposes of biosolids through any of the
practices addressed in the final regulations. An enforcement action can be taken against an individual who
does not meet those requirements, even in the absence of a permit.
4.1.1 40 CFR Part 503 Subpart B: Land Application
The land application category includes agricultural land application, forest application, land reclamation,
rangeland application, and distribution and marketing of any biosolids product that will eventually be
applied to land.
The land application requirements specify maximum concentrations and annual and cumulative loadings for
metals; the applicability of each is dependent on the biosolids quality and use. Land application
management practices are identified. Operational standards for pathogen reduction and vector attraction
reduction are also required and are discussed in detail in Section 4.1.3 of this TM.
Pollutant limits in Subpart B that apply to CBJ biosolids that may be land applied or marketed as soil
amendment are shown in Table 3 of this TM. As noted previously, CBJ’s biosolids fall safely under the federal
pollutant ceiling concentrations, based on MWWTP and JDWWTP biosolids samples analyzed in May 2014.
The Part 503 Rule precludes land application in the following circumstances:
• Where it is likely to adversely affect a threatened or endangered species or habitat
• To land that is flooded, frozen, or snow-covered so that biosolids enter a wetland or other waters of the
U.S.
• Within 10 meters of waters of the U.S.
• At a biosolids application rate greater than the agronomic rate (nitrogen based, determined by crop
need) of the site, unless otherwise specified by the permitting agency for a reclamation site
4.1.1.1 Pathogen and Vector Attraction Reduction for Land Application
Biosolids that meet the Class A pathogen requirements and meet the EQ pollutant limits are referred to as
“Exceptional Quality.” As such, these biosolids have minimal regulatory requirements. Biosolids that are
Class B with respect to pathogen requirements are restricted to bulk application to agricultural land, forest,
or reclamation sites. Additional site restrictions, such as food crop, grazing, and public access restrictions,
are specific to Class B biosolids. For Class B biosolids, one of the first 10 criteria specified under Subpart D
(described in Section 4.1.3) for vector attraction reduction must be met in order to land-apply biosolids.
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4.1.1.2 Potential Impacts to CBJ for Land Application of Biosolids
Based on analysis of recent samples, CBJ’s biosolids are able to meet the specified Part 503 Regulation
numerical limits for land application (Subpart B Tables 1-4). The critical limiting criteria will most likely be the
pathogen and vector attraction reduction requirements, depending on the end-use of the biosolids. Major
issues for every applier of biosolids are individual state and local requirements. State of Alaska requirements
are discussed in Section 5.1.
4.1.2 40 CFR Part 503 Subpart C: Surface Disposal
Generally, surface disposal refers to sludge-only landfills (monofills) and dedicated land disposal practices.
Subpart C of the Part 503 Rule applies to any person who prepares biosolids that are placed on a surface
disposal site, to the owner/operator of the site, and to the surface disposal site itself. This subpart does not
apply to biosolids stored on an area of land or to the land on which the material is stored. Storage, by
regulatory definition, is for biosolids that remain on-site for less than 2 years. If biosolids are in the same
location for more than two years, it is considered surface disposal whether or not ultimate disposal is the
intent. Should the CBJ desire to site and permit a sludge-only landfill, or monofill, the Part 503 Regulation
would apply, in addition to State of Alaska siting, permitting, and monitoring requirements.
The Part 503 Rule does not apply to the co-disposal of biosolids with other municipal solid waste in
municipal solid waste landfills. Co-disposal or use of biosolids at municipal solid waste landfills is regulated
under 40 CFR Part 258. Biosolids disposed in a municipal solid waste landfill must be non-hazardous and
pass the Paint Filter Test. Other site-specific requirements may apply depending on the landfill accepting the
material.
4.1.2.1 Pollutant Limits for Surface Disposal
Pollutant limits are specified for surface disposal sites without a liner and leachate collection system for
three metals: arsenic, 73 mg/kg; chromium, 600 mg/kg; and nickel, 420 mg/kg. The CBJ’s biosolids are safely
under these metal limits based on the data reviewed. If the pollutant concentrations exceed the specified
limits, and the site does not have a liner or leachate collection system, site-specific pollutants may be
requested at the time of permit application. The permitting authority must determine if site-specific
pollutant limits are appropriate.
4.1.2.2 Management Practices for Surface Disposal
The following requirements apply to surface disposal of biosolids:
• A surface disposal site must not adversely affect a threatened or endangered species or its habitat, and
it must not restrict the flow of a base flood.
• A surface disposal site must be designed to withstand certain seismic zone conditions.
• Runoff and leachate (for systems with a leachate collection system) must be collected and disposed of in
accordance with the site permit.
• Methane gas must be controlled and monitored if the unit is covered.
• Food, feed, and fiber crops must not be grown and animals must not graze on active sites unless it is
demonstrated that public health and the environment are protected. Public access to site must be
restricted until 3 years after closure.
• A groundwater-monitoring program must be developed to demonstrate that biosolids do not
contaminate any aquifer.
• Nitrogen in the groundwater must be monitored.
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WBG090414062923ANC 9
4.1.2.3 Pathogen and Vector Attraction Reduction for Surface Disposal
Class A or Class B pathogen reduction requirements must be met for biosolids disposed in a surface disposal
unit unless a daily soil cover is placed. If daily cover is not used, the biosolids must be Class A or Class B, and
must meet one of the alternative vector attraction reduction criteria specified in Subpart D of the Part 503
Rule.
4.1.2.4 Potential Impacts to CBJ for Surface Disposal
Biosolids generators who plan to use surface disposal sites must ensure that the biosolids meet the
pollutant concentration limits imposed for that site. Some monofills receive raw solids that will not meet the
Class A or B requirements. If a daily cover is placed, pathogen requirements do not have to be satisfied. The
CBJ’s biosolids meet the specified pollutant limits, but do not meet all pathogen and vector reduction
criteria. Therefore, daily cover for the surface disposal site would be recommended for any surface disposal
site, to minimize any pathogen and vector attraction concerns.
4.1.3 40 CFR Part 503 Subpart D: Pathogen and Vector Attraction Reduction
The Part 503 Rule states separate requirements for pathogen and vector attraction reduction. Pathogen
requirements have two classifications: Class A and Class B, with Class A being the more stringent. Current
processes to further reduce pathogens (PFRP) and processes to significantly reduce pathogens (PSRP)
technologies are recognized, but pathogen density criteria must be met in addition to the use of a specific
process.
Biosolids that meet the Class A pathogen requirements, one of the vector attraction reduction requirements
(criteria 1 through 8 in Subpart D), and the numerical criteria (pollutant concentration limits) in Table 3, are
referred to as “Exceptional Quality.” As such, these biosolids have minimal regulatory requirements.
Prior to the promulgation of the Part 503 Rule, the EPA used a technology-based approach to pathogen and
vector attraction reduction by requiring that biosolids undergo either PSRP or PFRP prior to being land-
applied. Although these processes are still recognized as acceptable, additional requirements are specified
to ensure process reliability.
As specified in Subpart D of the Part 503 Rule, either Class A or Class B pathogen reduction requirements
must be met when biosolids are applied to the land or placed on a surface disposal site. In addition, the
regulations require reduction of vector attraction, that is, control of those characteristics of biosolids that
attract disease-spreading agents (e.g., flies or rats) when applied to the land or placed on a surface disposal
site. There are no pathogen or vector attraction reduction requirements for biosolids fired in an incinerator.
Subpart B of the regulations prescribes operational standards that designate the level of pathogen reduction
for certain management methods, as shown in Table 5.
TABLE 5
Pathogen Reduction Requirements from 40 CFR Part 503 Rule
Management Method Requirement
Land Application (any) Class A or B
Surface Disposal Class A or B
Lawn or Home Garden Class A
Sold or Given Away in a Bag or Other Container Class A
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4.1.3.1 Class A Pathogen Reduction Options
All options require pathogen reduction to show that the biosolids have met either a fecal coliform or
Salmonella bacteria requirement and one of six alternatives:
• Demonstrate <1000 most probable number (MPN) fecal coliforms per gram total solids, or <3 MPN
Salmonella per 4 grams of total solids
• Apply one of six alternatives:
− Alternative 1 – Time and Temperature
− Alternative 2 – Raise pH
− Alternative 3 – Reduce enteric viruses and helminth ova (low pathogen biosolids)
− Alternative 4 – Reduce enteric viruses and helminth ova (normal biosolids)
− Alternative 5 – PFRP treatment
− Alternative 6 – PFRP equivalent treatment
4.1.3.2 Class B Pathogen Reduction Options
The three options for Class B pathogen reduction are:
1. Demonstrate 2 million MPN or coliform forming units (CFUs) fecal coliforms per gram total solids
2. Apply PSRP treatment
3. Apply PSRP equivalent treatment
In addition, there are a number of site restrictions for land application for Class B biosolids.
4.1.3.3 Vector Attraction Reduction
Twelve criteria are specified in the Part 503 Rule for vector attraction reduction. The application of vector
attraction reduction criteria depends on the type of biosolids and how they are to be used. For example, for
biosolids that are to be land-applied, biosolids must meet at least one of Criteria 1 through 10. For surface
disposal, any one of Criteria 1 through 11 may be used. Criterion 12 applies only to septage.
• Criterion 1. Volatile solids must be reduced by a minimum of 38 percent.
• Criterion 2. For anaerobically digested biosolids that cannot meet Criterion 1, bench-scale testing for 40
additional days at 30 to 37oC with 17 percent volatile solids reduction can be used.
• Criterion 3. Similar to Criterion 2 except that digestion takes place over 30 days at 20oC to show a
15 percent reduction.
• Criterion 4. The specific oxygen uptake rate (SOUR) for biosolids treated in an aerobic process shall be
equal to or less than 1.5 mg O2 per hour per gram of total dry solids.
• Criterion 5. For aerobic processes (e.g., composting), a minimum retention time of 14 days at 40oC must
be provided. An average temperature of 45oC must be maintained.
• Criterion 6. Sufficient alkali must be added to raise the pH to 12 or higher for a period of 2 hours, with
the biosolids remaining at a pH of 11.5 for an additional 22 hours without the use of additional alkali.
• Criterion 7. The total solids concentration of the portion of biosolids that does not contain unstabilized
primary solids should be a minimum of 75 percent prior to blending with other materials.
• Criterion 8. The total solids concentration of the portion of biosolids that does contain unstabilized
primary solids should be a minimum of 90 percent prior to blending with other materials.
• Criterion 9. Biosolids that are subsurface-injected must have no significant amount of biosolids on the
surface within 1 hour after injection.
• Criterion 10. Surface-applied biosolids must be incorporated within 6 hours after application.
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WBG090414062923ANC 11
• Criterion 11. Biosolids placed on an active surface disposal site must be covered each operating day with
soil or other material.
• Criterion 12. The pH of domestic septage must be raised to pH 12 by sufficient alkali addition for at least
30 minutes.
4.1.3.4 Potential Impacts to CBJ related to Pathogen and Vector Attraction Reduction
When evaluating future biosolids management options, the CBJ should consider the following pros and cons
associated with producing Class A versus Class B material:
• More alternatives are available for beneficial uses of Class A products.
• Regulatory monitoring and record keeping requirements are less stringent for Class A products than for
Class B materials.
• Typically, Class A stabilization requires higher O&M costs and more operator attention, which typically
increases overall processing costs.
• Producing Class A products may alleviate growing public perceptions and concerns about health effects
associated with pathogens.
• Consider the benefits from sale of Class A products such as heat-dried solids or compost.
4.1.4 40 CFR Part 503 Subpart E: Incineration
Subpart E of the Part 503 Regulation covers incineration. In particular, the following are specified: pollutant
limits; operational standards; and frequency of monitoring, record keeping, and reporting.
Incineration is an acceptable biosolids management alternative in areas of the country where the regulatory
and political climates are favorable, and few, if any, other biosolids management alternatives exist.
The construction of a new Sewage Sludge Incineration Unit (SSI) will require a Title V air permit under the
Clean Air Act. The facility must apply for a Title V operating permit within 12 months of starting the sewage
sludge incinerator. Title V requires a public hearing process. If it can pass the public hearing process and
other application requirements, an incinerator could be built at either JDWWTP or MWWTP. The operating
permit can be limited to the incinerator and the requirements in the permit should be the same as the
requirements in the minor source operating permit, should a minor source operating permit be required. If
no minor source operating permit is required, then the requirements of the Title V will be limited to the
emission limits for the sewage sludge incinerator and general requirements for reporting, record keeping
and annual fees based on the emissions from the incinerator. The Title V permit is not intended to add new
requirements for the facility, but to summarize requirements all in one place. The Title V permit and minor
source permit (if required) will be issued by the ADEC. State requirements are discussed in section 5.1 of this
TM.
4.2 Predicted Changes to Federal Part 503 Regulation and their Potential Impacts
In the last few years, public concerns have arisen regarding beneficial uses of biosolids mostly related to
Class B land application. These concerns have primarily centered on odors, aerosols, pathogens, and
perceived human-health impacts. In response to these concerns, the National Research Council (NRC) of the
National Academy of Sciences completed a study on the practice of biosolids land application and published
a report in a report entitled Biosolids Applied to Land: Advancing Standards and Practices (2003).
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The EPA summarized its review of the NRC report and resulting summit session in a Federal Register notice
including the following summary highlights:
• EPA will continue its biennial review of the biosolids standards and regulations as required by the Clean
Water Act. This means that information from biosolids research will be collected and analyzed every two
years to assess the need for regulation based on new research findings.
• EPA will continue to provide compliance assistance to the states and take enforcement actions as
appropriate.
• EPA will seek improved analytical methods for identifying and measuring pathogen levels in Class A and
Class B biosolids.
• EPA will conduct field studies and chemical pollutant surveys in efforts to assess the ecological and
human health impacts of biosolids land application.
• EPA will be involved in microbial risk assessment, exposure measurements, and stakeholder
communications in efforts to respond to public concerns with accurate scientific information.
• EPA will continue to assess the potential risks and impacts of additional contaminants as required by the
Clean Water Act. Pollutants that have recently been screened for risk assessment and potential
regulatory action include acetone, barium, beryllium, carbon disulfide, diazinon, manganese, butanone,
nitrate, nitrite, phenol, pyrene, and silver.
It is likely that some additional regulations will be imposed on biosolids quality and monitoring requirements
in the future. It is advisable for the CBJ to track these regulatory impacts and summarize them periodically.
5.1 Review of Pertinent State and Local Regulations
5.1.1 State Disposal Regulations
The ADEC is responsible for monitoring and enforcing compliance with the federal biosolids disposal
standards and the state solid waste regulations, found in the Alaska Administrative Code (AAC), title 18,
Chapter 60. The ADEC will review disposal systems and landfills and monofills to look for potential
compliance issues with both existing and proposed rules and standards. Changes and amendments are
made to these solid waste regulations from time to time and the City should make sure it is always working
from the most recent set of regulations.
18 AAC 60, as amended April 12, 2013, has the following articles, which affect the final disposal or reuse of
biosolids:
Article 3. Municipal Solid Waste Landfills
OR
Article 4. Monofills
Article 5. Land Application of Biosolids
5.1.1.1 Untreated Sewage Solids
Disposal of untreated sewage solids may be disposed of in a monofill and would be regulated under 18 AAC
60.470, Monofills - Sewage Solids. If the monofill is located within the boundaries of an existing municipal
landfill, it is considered co-disposal of sewage solids with municipal solid waste and would be regulated
under 18 AAC 60.365, Co-disposal of Sewage Solids. Any other regulations pertaining to landfill disposal
practices, design standards, water quality monitoring, and liquids restrictions would apply, as discussed in
Section 4.1.2.
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5.1.1.2 Monofills
By definition in 18 AAC 60, a monofill is a landfill or drilling waste disposal facility that receives primarily one
type of solid waste and that is not an inactive reserve pit. Monofill disposal of Class A biosolids would likely
still be considered sewage solids to ADEC. Achieving Class A or Class B status would satisfy the vector
reduction requirements of the regulation. Monofills may be lined or unlined, provided that they contain less
than certain levels of metal contaminant concentrations and that they are not placed near a fault, in an
unstable area, or in a wetland. Ongoing groundwater monitoring and post-closure care of the monofill will
likely be required. Regulations require a letter from the U.S. Fish and Wildlife Service stating that the
monofill is not likely to adversely affect a threatened or endangered species listed under 16 U.S.C. 1533
(Endangered Species Act,
Section 4) or its designated critical habitat.
5.1.1.3 Land Application of Biosolids
The federal regulations governing land application of solids established in 40 CFR 503 and discussed in
section 4.1.1 are adopted by reference by ADEC. Note that disposal of biosolids in a permitted monofill
would preclude their disposal under the category of land application. An ADEC approved permit is required
for any land application of treated biosolids that are not Class A. The monitoring constituents or parameters
will then be selected on a site-specific basis. The requirements of 18 AAC 60.500 - 18 AAC 60.510 do not
apply to the process used to treat domestic sewage or biosolids before their final use or disposal nor the ash
generated during the firing of sewage solids.
5.1.2 End Uses
5.1.2.1 Landfill Cover
A Class I landfill such as the Juneau Capital Landfill must cover solid waste with six inches of earthen material
at the end of each operating day. ADEC may approve an alternate cover material if the owner is able to
demonstrate that it will control disease vectors, wildlife attraction, fire, odor, blowing litter, and scavenging,
without posing a threat to public health or the environment. A Class A biosolids material by itself or blended
with soil could satisfy this regulatory requirement. Workability of the biosolids material may be questionable
for daily cover in high traffic areas. A Class A biosolids material may be more suited for final or interim
landfill cover in low traffic areas.
5.1.2.2 Mine Reclamation and Forestry Land Application
Biosolids can and have been used nationally as a soil amendment for mine reclamation sites. The nutrient
concentration of both the existing soil and the biosolids must be understood to produce a good mix for
revegetation. While, the Alaska Department of Natural Resources (ADNR) and ADEC regulate mine
reclamation and closure following under the State of Alaska Reclamation Act, there are no additional
regulations that would preclude the use of biosolids as a soil amendment. Forestry land is likewise overseen
by ADNR to monitor and ensure the integrity of the land.
Biosolids used as a soil amendment could be considered a resource for either mines or forest land. Land
application in this manner would be subject to the same Solid Waste Management Regulations listed above:
18 AAC 60, Article 5, as well as 40 CFR 503, adopted by reference.
5.1.3 State Air Regulations
The state air regulations are contained in 18 AAC 50, Air Quality Control. Air regulations encompass overall
ambient air quality and limit emissions from specific sources. When permitting a new source such as an
incinerator, CBJ must include all air pollutant sources on the site, cumulatively. In addition to the Title V air
permit required for any sludge incineration facility, state regulations may also require a construction permit.
Both permits will likely apply the standard operating permit conditions of 18 AAC 50.346.
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Incinerators are specifically regulated in 18 AAC 50.050 – Incinerator Emission Standards. Emissions are
limited both by concentration and by weight per unit time. Incinerators have a particulate matter (PM) limit
of 0.65 grams per kilogram of dry sludge input.
It is also possible that a Minor Permit may be required under 18 AAC 50.502. As a new source, the expected
emissions should be checked against the limits listed in Table 6. If emissions are below these thresholds, no
construction permit will be required.
TABLE 6
Minor Air Permit Limits
Pollutant Limit Unit
PM-10 15 tons per year
Nitrogen Oxides 40 tons per year
Sulfur Dioxide 40 tons per year
Lead 0.6 tons per year
PM-2.5 10 tons per year
Source: 15 AAC 50.502 (c) (1)
Any emissions from a CBJ WWTP will be added cumulatively to an existing inventory of pollutant sources in
the area. It is not expected that limits more rigorous than those listed in Table 6 or the EPA's health-based
standard will be imposed upon individual sources. The ambient air quality standards must be met in all
locations in the country at all times regardless of specific emissions in the area.
It may be noted that the Mendenhall Valley area of Juneau has been designated by the EPA as
"nonattainment" for PM-10, meaning that the air quality does not meet the ambient standard for small
particulate matter with a diameter of 10 micrometers or less. However, through the implementation of a
wood smoke control program and paving of unpaved roads, the PM-10 levels measured in the Mendenhall
Valley have been about a third of the 24-hour standard since the year 2000. The ADEC is currently in the
process of downgrading Juneau’s PM-10 status to maintenance. The PM-10 nonattainment issues are not a
factor in the ability to obtain a Title V operating permit. At this point, it appears the emissions from the
existing facility and the proposed biosolids alternatives would be low enough to meet the Table 6 limits.
5.1.4 Local Requirements:
The Municipal Code of the City and Borough of Juneau contains codified requirements which should be
reviewed prior to design. Chapter 36.40 – Solid Fuel-Fired Burning Devices was adopted to address airborne
pollutants in the area. In the Mendenhall Valley, an air emergency will be announced when air particulate
levels reach unhealthy levels. During air emergencies, all woodstove burning is prohibited; pellet stoves are
exempt from the wood stove regulations and can burn at any time. This section of the Municipal Code is also
adopted by reference in 18 AAC 50.030 and is thus enforceable at the State level.
Performance standards applying to industrial activity are outlined in Chapter 50 – Commercial and Industrial
Standards. The selected design shall not permit the emission of obnoxious odors or toxic or corrosive fumes
or gases. Dust or vapor shall not be exhausted directly into the atmosphere.
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6.1 Suggested Design Criteria for Biosolids Handling Facility
This subsection will briefly propose some general design criteria in terms of projected solids loadings and
general characteristics, so that the alternatives analyses can proceed without delay. Some adjustments and
refinements to these general design criteria may occur as the alternative analysis develops and we obtain
more information.
6.1.1 Proposed Solids Projections
Our review of area population projections and comprehensive plans indicates that the population and
economic activity of the CBJ service area will remain fairly stable for an indefinite period. In other words, no
significant increases or decreases in population and economic activity are expected over the 20-year
planning cycle of this study. Therefore, no significant changes in biosolids production rates from the
MWWTP and JDWWTP are expected over the next 20 years.
In view of the uncertainties in making 20-year projections, CBJ staff suggested in our May 8-9 project
workshop that it would be prudent to add a 10% contingency to current solids loadings for developing
design-year projections. Table 7 shows the proposed, general design criteria that we will issue to equipment
and system vendors during the upcoming, alternatives analysis phase of the project.
TABLE 7
Proposed General Design Criteria for Purpose of Developing Solids Management Alternatives
Design Criterion
JDWWTP
Solids MWWTP Solids
Combined
Solids Remarks
Average Annual
Solids Loading
0.8 DT/day 2.6 DT/day 3.4 DT/day Annual average loadings are used for
estimating O&M costs
Average Annual
Solids
Concentration
15% TS 15% TS 15% TS It is assumed that existing solids dewatering
capability can be maintained, but not
improved. Even though 15.8% TS was
achieved in 2013, 15% TS is assumed for
conservatism in design.
Average Annual
Solids Loading,
WT/day
5.3 WT/day 17.3 WT/day 22.6 WT/day This is the mathematical result of dry solids
loadings divided by %solids fraction.
Maximum
Month/Average Day
Peaking Factor
1.5 1.3 1.35 Slightly more conservative than existing
peak factors.
Maximum Month
Solids Loading,
DT/day
1.2 DT/day 3.4 DT/day 4.6 DT/day Monthly maximum daily values are assumed
for design with sufficient liquid storage
capacity to handle daily and weekly peak
loadings.
Maximum Month
Solids Loading,
WT/day
8.0 WT/day 22.7 WT/day 30.7 WT/day The maximum month, average daily
biosolids production rates in WT/day govern
sizing of drying and incineration equipment.
Other design criteria may be developed as the alternatives analysis proceeds.
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7.1 Summary and Conclusions
The present work by CH2M HILL is intended to build upon investigations already completed by CBJ and Tetra
Tech, Inc. into possible disposal and treatment alternatives. This TM has summarized CH2M HILL’s review of
data and information provided by CBJ in order to provide sufficient background to begin the current project.
This TM has also summarized the federal, state, and local regulations, providing a regulatory outlook for
CBJ’s future biosolids use or disposal options. The information received and data reviewed have been used
to develop design criteria for the upcoming analysis of biosolids management alternatives for CBJ, the
ultimate goal of which is a recommendation for a long-term biosolids management approach that is most
appropriate and sustainable for Juneau.
At the first project workshop held on May 7-8, 2014, CBJ and CH2M HILL team members reviewed the
history of the project and current issues and challenges that CBJ is facing. These include sludge constituents,
sampling issues, odors, landfill acceptance, lack of available land for development, and possible lack of
market for beneficial use of an end product. If CBJ sludge has a high metal content, objectionable odors, or
high levels of pathogen indicators, it will affect treatment and disposal methods.
Biosolids samples taken during this study and summarized herein indicate that levels of metals are safe and
well below EPA limits. Odors and pathogen levels can be reduced by appropriate treatment. While there are
a number of technologies that can convert biosolids topsoil amendments or low-grade fertilizers, any
investigation must include a determination of whether there would be sufficient market demand in Juneau
to use these products locally.
At the first project workshop, CBJ and CH2M HILL team members also discussed allowable risk tolerance.
The following US EPA definitions of emerging technologies for biosolids management were used:
• Established – Technologies widely used (i.e. generally more than 10 facilities throughout the world) are
considered well established.
• Innovative – Technologies meeting one of the following qualifications: (1) have been tested at a full-
scale demonstration site in this country; (2) have been available and implemented in the United States
(U.S.) for less than 5 years; (3) have some degree of initial use (i.e. implemented in less than ten utilities
in the U.S.;. and (4) are established technologies overseas with some degree of initial use in the U.S.
• Embryonic – Technologies in the development stage and/or tested at laboratory or bench scale. New
technologies that have reached the demonstration stage overseas, but cannot yet be considered to be
established there, are also considered to be embryonic with respect to North American applications.
Subsequent to the May workshop, CBJ received information on Wright Tech Systems’ Biodryer™ technology.
The “biodryer” is an in vessel composting system. As a composting system, the “biodryer” requires adding a
biomass, like woodchips, as a bulking agent. The technology was evaluated using the governing principals
established in first workshop. The CBJ eliminated composting as an acceptable technology due to insufficient
available land for a facility and the unknowns surrounding both the availability of wood chips for
amendment a local market for a compost product. Additionally, the biodryer technology has limited
experience with biosolids. Most of the applications have been small institutional installations using food
wastes as the compostable material. Any biodryer installations using biosolids are small in comparison to
Juneau’s biosolids production.
The Juneau area also poses some unique geographical challenges that point toward a need for more
established and reliable technologies. These challenges include a relatively remote location, limited
transportation options that may result in delayed shipments for equipment, an unpredictable climate, and
lack of specialized support services. Considering these factors, CBJ and CH2M HILL team members agreed
that the responsible choice for CBJ is to settle on an established or innovative technology that can
demonstrate a successful track record of operating facilities.
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The following three governing principles for selecting a biosolids management alternative were decided
upon at the first workshop:
1. Need Class A pathogen reduction to create an “exceptional quality” biosolids if desired
2. Need to have multiple options for end use to minimize risk of disposal
3. Need to maximize volume reduction to the extent possible.
Based on these governing principals, the following three alternatives were selected for more detailed
analysis:
1. Thermal dryer with production of Class A biosolids
2. Dryer with energy-recovery furnace
3. Stand-alone incinerator (fluidized bed type)
Evaluation criteria for the alternatives analysis were also established and weighted during the first project
workshop, as shown in Figure 2.
Ease of Operation Carbon Footprint Timeline for implementation Location of the technology Logistics of transport Public health & safety issues Environmental & permitting issues Risk End product disposal method Energy consumption & sourcing Score Weight
A B C D E F G H I J
Ease of
operation
A A A C A E F A H I A 5 0.09
Relative Carbon
Footprint
B B C B E F G H I J 2 0.04
Timeline for
implementation
C C C C F C H C C 8 0.15
Location of the
technology
D D E F G H I J 1 0.02
Logistics of
transport
E E F G H I J 4 0.07
Public health &
safety issues
F F F F F F 10 0.18
Environmental
& permitting
issues
G G H I J 4 0.07
Risk H H H H 9 0.16
End product
disposal method
I I J 6 0.11
Energy
consumption
& sourcing
J J 6 0.11
Sum of
Weights
1.00
FIGURE 2
Evaluation Criteria and Weightings to be Used in Biosolids Alternatives Analysis
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7.2 Path Forward
The next task is to proceed with the alternatives analysis under the design and evaluation criteria
established to date. The results of the alternative evaluation will be summarized in TM2, which will be
delivered to CBJ in early July, prior to Project Workshop 2, which will be held in Juneau on July 8-9, 2014.
WBG090414062923ANC 1
TECHNICAL MEMORANDUM 2
Biosolids Treatment and Disposal Evaluation–Phase II
Alternatives Evaluation and Results
PREPARED FOR: City/Borough of Juneau (CBJ), Alaska
PREPARED BY: CH2M HILL
DATE: August 7, 2014
1.1 Introduction
Objectives of this Technical Memorandum 2 (TM2) are as follows:
1. To summarize solids projections, characteristics, and conditions that comprise the design criteria for
long-term biosolids management options described herein
2. To present the results of the long-term solids management evaluation, including detailed descriptions of
the alternatives, the methodology used to evaluate alternatives, and evaluation results
3. To recommend an alternative for implementation, based on the results of the alternative evaluation and
discussion in Workshop 2.
This TM will also cover additional information obtained since Workshop 1 on biosolids characteristics and
results of additional testing not received in time for TM1. It will summarize the methodology and results of
the alternatives evaluation, and present additional issues to consider in selecting and implementing an
alternative. Finally, a recommendation will be made for the selected alternative.
2.1 Solids Loading Projections, Characteristics, and Design Conditions
Based on a review of historical conditions and projections of future conditions for the CBJ, Table 1 presents
design solids-loading criteria developed for biosolids management facilities at the Juneau-Douglas WWTP
(JDWWTP), the Mendenhall WWTP (MWWTP, which includes the Auke Bay WWTP solids), and combined
loadings from both facilities. The units describing biosolids quantity are in dry tons per day (DT/day) and wet
tons per day (WT/day). The projected loadings are based on historical trends summarized in the Phase 1
report, supplemented by data from calendar year 2013, with the addition of 10% reserve capacity to
account for the potential of increased industrial activity and population growth in the future.
Belt filter presses at both WWTPs produced an average of 15.8% solids in 2013, but WWTP production
records show that dewatered cake solids range from 14% to 17% solids on a day-to-day basis. For sizing of
future biosolids handling facilities, it is conservatively assumed that dewatering facilities at both WWTPs will
produce 15% Total Solids (TS). If the dewatering operations can produce solids of higher TS content than
15% TS in the future, then the future biosolids handling facilities will have additional reserve capacity, which
will provide for more redundancy and flexibility in operations.
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TABLE 1
Proposed General Design Criteria for Purpose of Developing Solids Management Alternatives
Design Criterion
JDWWTP
Solids MWWTP Solids
Combined
Solids Remarks
Average Annual
Solids Loading
0.8 DT/day 2.6 DT/day 3.4 DT/day Annual average loadings are used for
estimating O&M costs
Average Annual
Solids
Concentration
15% TS 15% TS 15% TS It is assumed that existing solids dewatering
capability can be maintained, but not
improved. Even though 15.8% TS was
achieved in 2013, 15% TS is assumed for
conservatism in design.
Average Annual
Solids Loading,
WT/day
5.3 WT/day 17.3 WT/day 22.6 WT/day This is the mathematical result of dry solids
loadings divided by %solids fraction.
Maximum
Month/Average Day
Peaking Factor
1.5 1.3 1.35 Slightly more conservative than existing
peak factors.
Maximum Month
Solids Loading,
DT/day
1.2 DT/day 3.4 DT/day 4.6 DT/day Monthly maximum daily values are assumed
for design with sufficient liquid storage
capacity to handle daily and weekly peak
loadings.
Maximum Month
Solids Loading,
WT/day
8.0 WT/day 22.7 WT/day 30.7 WT/day The maximum month, average daily
biosolids production rates in WT/day govern
sizing of drying and incineration equipment.
Biosolids characteristics were derived from dewatered cake samples taken in May 2014. The first set of
sample results were presented in TM1. They indicate that CBJ’s biosolids are typical of undigested waste
activated solids (WAS) in the case of MWWTP, showing 90% volatile solids (VS) content. In the case of the
Juneau-Douglas WWTP (JDWWTP), the lower VS content of 82% VS indicates that WAS from the JDWWTP is
partially digested. Other aspects of biosolids from the two WWTPs are typical of biosolids from other
WWTPs.
Additional analytical results were received on June 20, 2014, from Hazen Laboratories in Denver, CO, which
summarize the potential fuel value of biosolids samples from MWWTP and JDWWTP based on ultimate and
proximate analyses of biosolids combustibility and energy potential. Those analytical results are summarized
in Table 2.
The sample results shown above are consistent with the laboratory results of other standard parameters
reported in TM1. The results show that MWWTP solids have higher fuel value than JDWWTP solids, primarily
because the MWWTP solids are not digested, while JDWWTP solids are partially digested. If a central facility
is built for incinerating the solids from both WWTPs, it would not be necessary to continue aerobically
digesting the JDWWTP solids. Not digesting the solids at JDWWTP could save energy, increase the
dewatering potential of JDWWTP solids, and increase the fuel value of its waste solids. Not digesting the
solids will increase the mass of dewatered biosolids from JDWWTP slightly and may increase the odor
potential of JDWWTP solids, however.
Overall, both JDWWTP and MWWTP solids have a relatively high fuel value if they are dried sufficiently to
allow for combustion. The relatively low total solids content in the dewatered solids from these WWTPs
(14.5% TS at the JDWWTP and 17.3% TS at the MWWTP from grab samples) requires the evaporation of
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large amounts of water, with its attendant high energy costs, before the biosolids from these WWTPs can be
combusted and the fuel value can be fully recovered.
TABLE 2
Selected Results from Ultimate & Proximate Analysis of Solids from JDWWTP and MWWTP
Constituent
JDWWTP
Sample
Results1
MWWTP
Sample
Results1 Remarks
Percent Solids 14.5% 17.3% Expressed as % of total mass, the remainder being water;
shows better dewatering at MWWTP than at JDWWTP
Volatile Solids (Organic
Matter)
73.1% 80.8% Expressed as % of total solids above, volatile solids are a sign
of fuel value and biological stability. MWWTP solids are not
digested and have higher fuel value and lower stability than
JDWWTP solids.
Ash Content 16.9% 10.2% Ash is the remaining dry matter that is not volatile and
consists primarily of nutrients, silica, and metals
Fixed Carbon 10.0% 9.0% JDWWTP fixed carbon is slightly higher than MWWTP,
reflecting that JDWWTP solids have been digested
Sulfur 1.0% 0.7% Indicates higher level of sulfur in wastewater influent to
JDWWTP, but sulfur is not high enough at either WWTP to
pose a problem
Lower Heating Value
(LHV), Btu/lb
7500 7855 Heating value of dried solids if no combustion heat is
recovered
Higher Heating Value
(HHV), Btu/lb
8040 8455 Heating value of dried solids if all combustion heat is
recovered
Mineral Matter Free
(MMF) Heating Value,
Btu/lb
9506 9842 Represents total heating value of solids without interference
by inert mineral matter
1 Dewatered biosolids cake sampled on May 14, 2014, and analyses reported on June 19, 2014.
3.1 Description of Alternatives
The alternatives for biosolids management by the CBJ are being evaluated in this TM:
1. Continuation of the current practice of shipping dewatered biosolids from the JDWWTP and the
MWWTP by barge to Oregon for landfill disposal (also known as the “status quo” or “base case”
alternative.
2. Thermal drying of biosolids at a central facility with local disposal or marketing of the dried, Class A
biosolids product.
3. Thermal drying of biosolids followed by combustion (incineration) of the biosolids to recover heat that is
then recirculated to the biosolids drying process, thus reducing the amount of purchased fuel.
4. Thermal combustion (incineration) of the biosolids in a new fluidized-bed incinerator that recovers heat
from the combusted biosolids to aid in evaporation and reduce the amount of purchased fuel.
Each of the alternatives that require a new biosolids drying or incineration facility (Alternatives 2-4 above)
have been evaluated based on locating new drying or incineration facility at one central location, either at
the JDWWTP or the MWWTP.
The advantages and disadvantages of locating new facilities at the MWWTP or the JDWWTP are:
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1. MWWTP Location Advantage: The MWWTP currently produces 79% of CBJ’s biosolids, with most of the
future growth in Juneau predicted to be in the MWWTP service area. Locating central biosolids
processing facilities at the MWWTP would reduce the truck traffic and associated costs of cross-town
hauling of dewatered biosolids, since only about 20% of CBJ’s biosolids would have to be transported
from the JDWWTP to the MWWTP.
2. MWWTP Location Advantage: The MWWTP is closer to the Capital Landfill than the JDWWTP, which is
the primary disposal option for the dried biosolids or ash that would be produced by these alternatives,
so there would be less vehicle mileage for hauling dried product or ash.
3. JDWWTP Location Advantage: The MWWTP is located in the Mendenhall Valley, which is currently a
non-attainment area for particulate matter in air emissions. A biosolids dryer or combustion unit may
need tighter air emissions controls and obtaining an air emissions permit may be more difficult at
MWWTP than JDWWTP, especially since the JDWWTP previously had an air emissions permit for the
fluidized-bed incinerator (FBI) that has been decommissioned.
4. JDWWTP Location Advantage: The JDWWTP has more space available onsite for locating a new
biosolids facility than the MWWTP, which only has the location of an existing building (called the ABF
Building) for siting new biosolids facilities. A new biosolids facility at the MWWTP would therefore
require demolition of an existing structure, while a new biosolids facility could be built at the JDWWTP
with minimal demolition.
5. JDWWTP Location Advantage: The JDWWTP does not have neighbors in close proximity like the
MWWTP does. The MWWTP neighbors have periodically filed complaints related to odors from the
MWWTP. It is believed that the JDWWTP would be less subject to odor and nuisance complaints than
the MWWTP, due to its location in an industrial zone next to a shipping dock and more land available for
a buffer zone.
Recognizing the possibility that a central biosolids facility may be located at the JDWWTP or the MWWTP, a
Benefit/Cost analysis was developed for the two alternative locations, as described later in this TM.
The following subsections describe each of the technical alternatives in more detail. The first alternative
assumes that CBJ will continue its current practice as described below. The other three alternatives assume
that new facilities for handling biosolids will be built at either the MWWTP or the JDWWTP.
3.1.1 Alternative 1 - Continuing the Transport and Landfilling of Dewatered Biosolids
Since the fluidized-bed incinerator (FBI) at the JDWWTP was decommissioned in 2011, CBJ has been
landfilling all of its dewatered biosolids. Some of the biosolids have been landfilled at the local Capital
Landfill in Juneau, but most of the biosolids are shipped by barge, rail, and truck to the Columbia Ridge
Landfill in Arlington, Oregon. A summary of biosolids production and disposal in Calendar Year (CY) 2013 is
shown in Table 3.
Table 3 indicates that 6,992 WT of biosolids were produced at CBJ’s two WWTPs, based on WWTP monthly
operating reports, as shown in the 2nd column. Biosolids disposal records from WM are shown in the next
two columns of Table 3. They indicate that as recently as July 2013, significant quantities of biosolids
(430 WT) were disposed of locally at the Capital Landfill in Juneau. The average tipping fee for biosolids
disposed of at the Capital Landfill was reported to be $88 per WT. The average fee for biosolids transport by
barge and rail and disposal at the Columbia Ridge Landfill in Oregon was reported to be $140 per WT in
2013, but that fee was recently increased to $215 per WT.
The reason given for rejection of biosolids by the Capital Landfill has been odors from the dewatered
biosolids, which prompted complaints from Capital Landfill’s neighboring commercial developments. It is not
believed that odors from the biosolids can be mitigated unless a new process such as heat-drying or
incineration is installed to further treat the dewatered biosolids.
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TABLE 3
Summary of CBJ Biosolids Disposal Amounts in Wet Tons (WT) in Calendar Year (CY) 2013
Month in CY 2013
Biosolids
Production, from
WWTP Records,
WT
Disposal at
Capital Landfill
in Juneau,
WT
Disposal at
Columbia Ridge
Landfill in Oregon,
WT
Total Biosolids
Disposed, from
WM Records,
WT
January 526 35 212 247
February 697 0 372 372
March 642 0 602 602
April 611 191 431 622
May 657 128 821 949
June 539 0 558 558
July 577 430 274 704
August 610 0 491 491
September 524 0 368 368
October 702 0 810 810
November 442 0 637 637
December 465 0 458 458
Total WT Biosolids Recorded for CY 2013 6,992 784 6,033 6,817
As shown in Table 3, there are variances between the monthly totals of dewatered biosolids produced, as
shown in WWTP records (2nd column) and the monthly totals of biosolids disposed, shown in WM records
(last column). These variances can be attributed biosolids cake storage practices prior to transport and
disposal. The difference between total biosolids produced and disposed of in CY 2013 is only 2%, which
again can be attributed to the timing of biosolids storage and disposal.
The current costs for landfill disposal are estimated to be approximately $1.5 million (M) in equipment costs,
prior to markups, and approximately $1.8 M annually in O&M costs before a 10% contingency is applied.
After markups on equipment costs, the capital costs associated with Alternative 1 are $3.2 M and annual
O&M costs total $2M.
3.1.2 Alternative 2 - Thermal Drying Technology
In the most general terms, thermal drying is the use of heat to evaporate water from wastewater residual
solids. The drying system, in addition to the dryer itself, generally consists of materials handling and storage
equipment, heat generation and transfer equipment, air movement and distribution equipment, emissions
control equipment, and ancillary systems. Drying systems use different methods for heat transfer, including
convection, conduction, and radiation heating. To some extent, multiple methods of heat transfer are used
by individual systems, but they are generally categorized by their primary method of heat transfer.
Systems that primarily use convection for heat transfer are often referred to as “direct” dryers. In direct
heat dryers, hot air/gas flows through a process vessel and comes into direct contact with particles of wet
solids. The contact between the hot air and cold wet cake allows the transfer of thermal energy, which
causes an increase in wet cake temperature and evaporation of water. The hot air/gas can be produced by
almost any source of heat, but most often is produced by a gas or oil-fired furnace. Since natural gas is not
available at CBJ’s WWTPs, the drying systems proposed for Juneau are based on utilizing No. 2 heating oil for
fuel.
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Examples of direct drying equipment are rotary drum dryers and belt dryers. Belt dryers are most popular
for smaller systems that would be typical of the size needed by CBJ, because they are more readily scaled
down than the rotary drying systems typical of larger WWTPs. Belt dryers are also inherently safer and
simpler to operate because they operate at lower temperatures of 300oF (150 oC) as opposed to rotary
dryers, which operate at 800-900oF (425-480oC). Therefore, the belt drying system is recommended for
consideration by CBJ.
Belt dryers use direct contact of circulating hot air with wet sludge. Sludge is pumped or otherwise
distributed onto a slowly moving horizontal belt enclosed in a housing. The wet material moves through one
or more drying chambers, where the moisture is released into the circulating air. After passing through the
drying chambers, the dried cake falls off from the belt onto a hopper and is conveyed to a loading or storage
facility. Each drying zone has its own circulating fans and air temperature control. Excess moisture is
removed from the air stream in a saturator or vented directly to atmosphere. Heat for the air circulation
loop in each zone is provided in a heat exchanger by indirect contact with steam, hot water, thermal oil, or
hot air serving as the heat source. The drying temperatures are controlled at approximately 300°F (150 oC)
at the belt entry and at 210°F (100 oC) at the belt discharge. The sludge is heated to approximately 170°F
(75 oC). The lower drying temperature is claimed to produce a less odorous air stream.
The size and shape of the dried material produced depends on shape and size of the feed and can be
composed of larger fragments, non-uniform in shape, with sizes between 1 and 10 mm. Vendors have
developed several types of feed systems. The most common include using an extruder and knife to produce
a spaghetti-shaped pellet and providing back-mixing and a screw feeder to shape and distribute the feed
evenly across the belt. Utilizing recycled dried material has also been used to produce a uniformly sized
pellet. A pelletizer may be added if smaller pellets of uniform size are desired. Since the sludge is not
excessively moved in this system, dust formation is reduced.
A schematic diagram of a typical belt drying system is shown in Figure 1, and a photograph of the dried
biosolids product typical to a belt drying system is shown in Figure 2.
The most common and prevalent belt-drying system worldwide is manufactured by Kruger, a division of
Veolia Technologies. CH2M HILL worked with Kruger to provide a conceptual design and preliminary budget
quote for this project, based on its BioCon Belt Drying system. Another advantage of the BioCon Belt Drying
System is an energy recovery system (ERS) that Kruger developed to combust the dried biosolids and recycle
the heat energy from combustion back to the dryer. The belt dryer with energy-recovery combustion
furnace is described in the next subsection.
3.1.3 Alternative 3 - Thermal Drying followed by Incineration for Heat Recovery
The Kruger BioCon - Energy Recovery System (ERS) process utilizes drying to substantially decrease the
water content of the sludge prior to incineration. Energy is recovered by using the dried biosolids as fuel for
the furnace, which in turns heats the air that dries the biosolids. Wood pellets can also be used whenever
there are not sufficient dried biosolids for a fuel source. Additional energy is recovered by a heat exchanger
system which extracts heat from the water removed by drying. The final product of the furnace is an inert
ash at > 98% solids content. Alternatively, the dryer can operate without the furnace and produce dried
biosolids pellets at 90% solids as described above in Alternative 2, but in that case, No. 2 heating oil is the
only fuel used for providing the heat to dry to the biosolids.
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FIGURE 1
Belt Drying Process Schematic
FIGURE 2
Dried Biosolids Product from a Belt Dryer (courtesy of Kruger)
SLUDGE FROM
DEWATERING SYSTEM
DISTRIBUTION DEVICE
CONDENSER
HEATING MEDIUM
FROM BOILER/HEX
DRIED SLUDGE
FINAL
EFFLUENT
CONDENSATE AND WARM
RETURN TO PLANT INFLUENT
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Supplemental fuel for the furnace is still needed for the BioCon-ERS dryer, because of the relatively high
water content of biosolids produced by the belt filter presses at JDWWTP and MWWTP. Heat is recovered
from the water in the dryer exhaust and used to preheat the biosolids going into the dryer, but the air from
the furnace is the primary source of heat to the dryer. The dryer and furnace exhausts are scrubbed to
remove any pollutants and discharged to the atmosphere. The resulting ash can be mixed with soil and
placed in the landfill or used as a fly ash substitute in construction projects using concrete. If the dried
pellets (Figure 2) are not incinerated, they may be used as fertilizer or soil amendment.
Figure 3 illustrates the Kruger BioCon-ERS process. Dewatered sludge is stored in the sludge silo until there is
enough to conduct a dryer run. Solids are pumped into an extrusion device and distributed on the belt. They
are dried with hot air from the furnace which combusts dried biosolids. A photo of the furnace from a
Kruger BioCon-ERS unit installed in Buffalo, Minnesota, is shown in Figure 4.
FIGURE 3
BioCon Dryer and Energy Recovery System (BioCon-ERS) Process
FIGURE 4
BioCon-ERS Incinerator Furnace
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3.1.4 Alternative 4 – New Fluidized Bed Incinerator
CH2M HILL worked with Infilco-Degrement, Inc. (IDI) on recommendations for the incineration alternative.
IDI manufactured and supplied the de-commissioned FBI unit at the JDWWTP, installed in the 1970’s. After
reviewing the reports and current status of CBJ’s decommissioned and abandoned FBI unit at the JDWWTP,
IDI’s technical representatives concluded that the costs and risks of rebuilding the existing FBI unit to comply
with present-day regulatory standards and technologies would be higher than the costs and risks of
installing a completely new FBI unit that is designed to comply with all current standards. Therefore, IDI
prepared a conceptual design and budget proposal to provide a new FBI unit, to be located at the MWWTP.
An FBI built to present-day EPA standards is a complex system with many components. A typical process-
flow schematic for an FBI unit is shown in Figure 5.
FIGURE 5
Typical Fluidized Bed Incinerator (FBI) and Accessories
The following subsections describe the alternative-evaluation methodology and results of the alternatives
evaluation.
4.1 Alternatives Evaluation
The methodology used to evaluate the four alternatives described above is based on the multi-attribute
utility analysis (MUA) concepts of decision science. In the MUA evaluation approach, non-monetary criteria
and life-cycle cost estimates are combined to rank the alternatives according to the quantitative term of a
Benefits/Cost (B/C) ratio. The evaluation methodology is described in this section.
4.1.1 Review of Evaluation Criteria, Weighting, and Ranking
In order to arrive at the B/C ranking of alternatives, the non-monetary criteria must first be developed, then
weighted and ranked to arrive at quantitative rankings of each alternative according to each of the non-
monetary criteria. The non-monetary criteria were initially developed and assigned relative weightings in
Workshop 1. Then in Workshop 2, the criteria were revisited and revised. The weightings are numerical
fractions of 1.00 that were derived in a criteria-prioritization exercise that was held among Workshop 2
participants. The results are shown in Table 4. The alternatives were later scored against the criteria based
on a high probability of meeting or exceeding current and future needs (high score) or low probability of
meeting or exceeding current and future needs (low score). Scoring is discussed further in Section 1.4.3.
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TABLE 4
Results of Developing and Weighting Non-Monetary Criteria Used in Alternatives Evaluation
Criteria
No.
Evaluation
Criteria
Criteria
Weights Criteria Description
1 Ease of operation 9.1 Relative ease of operating the technologies involved in each alternative, compared
to existing operations. Technologies considered easier to operate receive higher
score.
2 Carbon footprint 3.6 An estimate of the amount of greenhouse gas (GHG) emissions that would be
emitted as a result of implementing each of the alternatives. Lower GHG emissions
receive higher score.
3 Timeline for
implementation
14.5 Estimated time required to implement each alternative, relative to other
alternatives. Alternatives with faster timeline receive higher score.
4 Location of the
technology
1.8 Flexibility to locate the facilities involved in each alternative at any one of three
possible locations (JDWWTP, MWWTP, and Capitol Landfill) relative to other
alternatives. Alternatives with greater location flexibility receive higher score.
5 Logistics of
transport
7.3 Ease or difficulty in which end product from each alternative (dewatered cake,
dried solids, or ash) can be transported, relative to other alternatives. Alternatives
with end products considered easier to transport receive higher score.
6 Public health &
safety issues
18.2 Possibility of each alternative to create public health or safety issues relative to the
other alternatives. Greater possibility of creating issues results in lower score.
7 Environmental &
permitting issues
7.3 Likelihood of each alternative to encounter environmental or permitting problems,
relative to the other alternatives. Higher likelihood of problems results in lower
score.
8 Risk 16.4 The amount of risk associated with implementing each alternative, from the
perspectives of new technology, process complexity, and possibility of failure
during operations, relative to the other alternatives. Alternatives with higher risk
receive lower score.
9 End product
disposal method
10.9 Likelihood of each alternative to experience ease or difficulty with end product
disposal. Greater anticipated difficulty results in lower score.
10 Energy
consumption &
sourcing
10.9 Estimated amount of energy and source of energy required by each alternative
compared with the other alternatives. Higher score to alternatives with lower
energy requirements and higher scores to alternatives that can create energy or
use local energy sources.
Total Weight 100.0
4.1.2 Carbon Footprint Estimates and Comparisons between Alternatives
“Carbon Footprint” is the term used to express and compare a facility’s estimated contribution to global
warming via its estimated emissions of greenhouse gases (GHG’s) to the atmosphere. A number of GHG’s
have been identified as contributors to global warming, but the only GHG’s of consequence in wastewater
treatment and biosolids management are the following three gases:
1. Carbon dioxide (CO2): The most common GHG; all other GHG’s are converted to carbon-dioxide
equivalents (CO2e) when estimating total GHG emissions.
2. Methane (CH4): The next most common GHG found in wastewater and biosolids after carbon dioxide,
methane is the primary gas product of anaerobic respiration, and is 23 times more potent than carbon
dioxide as a GHG. Therefore one unit of methane = 23 units of CO2e.
3. Nitrous oxide (N2O): The least common of the three GHG’s associated with wastewater and biosolids,
nitrous oxide is a by-product of nitrification and denitrification reactions. Even though nitrous oxide is
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typically emitted in smaller amounts than carbon dioxide and methane, it is 300 times more potent than
carbon dioxide as a GHG. One unit of nitrous oxide = 300 units of CO2e.
The summation of these three GHG’s, when all are converted to CO2e, represents the total estimated
Carbon Footprint of an alternative. The Total Carbon Footprint consists of direct and indirect emissions of
CO2e, which are categorized in the following three groups for purposes of estimating total GHG emissions:
1. Scope 1 GHG emissions – These are the direct emissions of GHG’s arising from a process or activity.
However, CO2 emitted as a result of natural biological activity, known as “biogenic CO2 emissions” are
not typically counted as part of the total carbon footprint. CO2 emissions resulting from combustion of
fossil fuels, known as “anthropogenic CO2 emission,” are typically counted in the total carbon footprint.
All of the carbon dioxide emitted from fossil-fuel based engines or processes is included in Scope 1 GHG
emissions. In addition, all methane and nitrous oxide emissions from these processes are counted as
Scope 1 GHG emissions, whether or not the methane or nitrous oxide is emitted from biogenic or
anthropogenic sources in the processes.
2. Scope 2 GHG Emissions – These are indirect emissions of GHG’s resulting mostly from combustion of
fossil fuels used to produce electrical power, heat, or steam that is delivered to an activity or process.
Since the primary electrical power in Juneau is produced by hydro-powered turbines, the fossil fuel use
in power production is negligible, and Scope 2 emissions are therefore negligible for purposes of this
comparison.
3. Scope 3 GHG Emissions – These are indirect emissions of GHG’s resulting from the production of
purchased chemicals and materials, and the uses of end products produced by an alternative. Scope 3
emissions tend to be remote from the source of an activity or process. Scope 3 GHG emissions are not
considered in the following estimates of GHG emissions, or Carbon Footprint, associated with the four
alternatives being evaluated.
Based on the explanations given above, only Scope 1 (Direct) GHG emissions were considered when
comparing the Carbon Footprint of each alternative being evaluated. Results of the Carbon Footprint
estimates are shown in Table 5.
TABLE 5
Estimated Annual Greenhouse Gas (GHG) Emissions (Carbon Footprint) of Each Alternative
Alternative
Estimated GHG Emissions (CO2e) in metric
tons per year (Mg/year), based on Scope 1
(Direct) GHG Emissions
1- Status Quo 2,700
2- Thermal Dryer Fueled No. 2 Heating Oil 1,900
3- Thermal Dryer + Combustion for Energy Recovery 980
4- Direct Combustion via Fluidized-Bed Incinerator (FBI) 1,200
As shown in Table 5, Alternative 3 – Thermal Dryer with Energy Recovery System, is estimated to have the
lowest Scope 1 emissions of GHG’s, i.e., the smallest Carbon Footprint, of the four alternatives. The primary
reason for Alternative 3 having the smallest Carbon Footprint is because it uses dried biosolids for
combustion and heat recovery to help fuel the biosolids dryer, thereby substantially reducing the amount of
fossil fuel (No. 2 heating oil) needed to dry or combust biosolids, when compared with Alternatives 2 and 4,
respectively. Alternative 1 – Status Quo, has the highest Carbon Footprint primarily because landfilling of
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biosolids results in anaerobic activity and high emissions of methane from the landfill. Additionally, fossil
fuels are used to transport biosolids from the MWWTP and JDWWTP first by truck, barge, and rail, prior to
being landfilled in the State of Oregon, thereby contributing to the large Carbon Footprint of Alternative 1.
4.1.3 Non-Monetary Comparison of Alternatives
Each of the four alternatives non-monetary criteria were ranked by CBJ and CH2M HILL staff. The results of
these rankings are shown in Table 6 and Figure 6. A score of “5” indicates the highest possible score, in that
the alternative shown would rank highest in being able to meet the criterion described. Conversely, a score
of “1” indicates the lowest possible score for an alternative to satisfy that criterion.
TABLE 6
Results of Developing and Weighting Non-Monetary Criteria Used in Alternatives Evaluation
Criteria Number 1 2 3 4 5 6 7 8 9 10
Total
Score
Criteria Name Ease of Operation Carbon Footprint Timeline Location Transport Public Health Permitting Risk Disposal Energy
Weight 9.1 3.6 14.5 1.8 7.3 18.2 7.3 16.4 10.9 10.9
1: Maintain Status Quo 2 1 5 1 1 1 1 4 1 2 20.7
2: Thermal Drying 3 3 3 3 3 3 3 3 3 2 26.3
3: Thermal Drying with Heat-
Recovery Furnace 2 4 2 2 4 4 2 2 4 4 27.4
4: Thermal Oxidation
(Incineration) 2 4 2 2 4 4 1 3 4 2 26.3
A graphical depiction of the alternative rankings with respect to non-monetary criteria is shown in Figure 6.
As shown, Alternative 3 (Dryer and Heat-Recovery Furnace), ranked highest in non-monetary terms,
Alternative 2 (Thermal Drying), followed by Alternative 4 (Incineration) ranked next highest, and finally,
ranked last, is Alternative 1 (Continued Status Quo of Landfill Disposal). The non-monetary criteria rankings
shown in Table 6 and Figure 6 apply to either the MWWTP or JDWWTP facility location.
The cost estimates for each alternative change slightly depending on whether the biosolids treatment
facility is located at the MWWTP or JDWWTP, as described in the next section of this TM.
4.1.4 Methodology for Cost Estimation
Cost estimates including capital costs, annual operation and maintenance (O&M) costs, and net present
value, also were developed. All costs were derived using the same level of estimating accuracy and are
therefore comparable. Actual construction costs may differ from the estimates presented, depending on
specific design requirements and the economic climate at the time a project is bid. The American
Association of Cost Engineers (AACE) has developed levels of accuracy for various stages of construction cost
estimation. The estimates produced for the current comparison are Class 5, with a corresponding project
definition level of 0-2% and expected level of accuracy of 20-50% below and 30-100% above the cost given.
Basic cost assumptions are shown in Table 7.
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FIGURE 6
Stacked Bar Chart Display of Non-monetary Criteria Rankings of Alternatives 1-4
TABLE 7
CBJ Reference Unit Costs
Effective Discount Rate, % 3%
Inflation Rate 2%
Discount Rate, % 5%
Planning Period (and Finance Period), years 20
Power Cost, $/kWH $0.07501
Staffing Cost, $/hr $45.00
Staffing Cost, $/FTE/yr $93,600
Building Cost (with odor control), $/sf $200
No. 2 Fuel Oil $/MMBtu $31
1 Current Cost from CBJ.
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Cumulative Criteria ScoresProjects
Ranking of Alternatives
by Total Benefit Value
Ease of operation Carbon Footprint Timeline for implementation
Location of the technology Logistics of transport Public health & safety issues
Environmental & permitting issues Risk End product disposal method
Energy consumption and sourcing
2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
1: Maintain Status Quo
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4.1.5 Cost Comparison of Alternatives
Capital cost estimates for each of the alternatives are included in Table 8 and Table 9. Capital cost
components for alternatives 2-4 were taken directly from vendor provided information. For the Status quo
option, it is assumed that some investment in additional equipment would be required and a placeholder
amount has been included. Other costs and markups have been calculated as a percentage of the capital
investment, based on standard market practice. The capital costs vary slightly depending on whether the
alternative would be located at the MWWTP or JDWWTP, as shown by comparing Tables 8 and 9. For
example, if the biosolids treatment facility is located at the JDWWTP, it will require larger truck-loading and
biosolids storage facilities, because of the greater volume of biosolids that would be trucked in from the
MWWTP.
It is assumed that all capital costs are incurred over the initial two years of the project period. Then annual
O&M costs are projected over the 20-year life-cycle. Cost estimates were reviewed and revised in
Workshop 2.
The construction cost estimates shown in Tables 8 and 9 are conservative and include large contingencies,
which are required for Class 5 cost estimates.
The annual Operations and Maintenance (O&M) costs shown in Table 10 and Table 11 were also taken
directly from vendor provided information for alternatives 2-4 and using the unit costs shown in Table 7. An
annual maintenance and repairs allocation was included in each of the vendor quotes to address wear and
tear of equipment. The O&M costs for the status quo option are based on estimates of hauling and landfill
costs per wet ton and may not accurately depict all of the costs currently incurred by CBJ. Similar to capital
costs, O&M costs for each facility location are slightly different because the amounts of biosolids trucked
between WWTPs differs depending on location, as shown by comparing Tables 10 and 11.
The total combined cost of capital investment and O&M was then summarized to calculate the net present
worth of each alternative, assuming a 20-year planning period. The total cost of each alternative in today’s
dollars is shown in Table 12 for the MWWTP facility location, and Table 13 for the JDWWTP facility location.
A graphical depiction of these values is provided in Figure 7 and Figure 8, which show the breakdown of
capital vs. O&M costs for each alternative. In order to create a meaningful comparison for discussion, all of
the new alternatives are shown relative to the status quo alternative, which is represented as a baseline
100% relative cost. Figure 7 represents the MWWTP facility location, and Figure 8 represents the JDWWTP
location.
4.1.6 Benefit-cost Comparison of Alternatives
The non-monetary criteria discussed in Section 4.1.3 were then combined with the total costs to produce a
Benefit-cost score, shown in Tables 14 and 15, for the MWWTP and JDWWTP facility locations, respectively.
In this evaluation, following the traditional procedure for Benefit/Cost evaluations, the total non-monetary
scores were assigned a 50% weighting and the NPV scores were assigned the remaining 50% weighting in
computing the Benefit/Cost scores of each alternative. As with the O&M and capital cost comparisons, each
of the new alternatives is shown as having a higher or lower benefit-cost score than the Status Quo
alternative, which is assigned a 100% baseline score.
Figures 9 and 10 depict the relative Benefit/Cost scores of each alternative in bar chart format.
As shown in the figures and tables above, Alternative 2 (Thermal Drying) and Alternative 3 (Thermal Drying
with Energy-Recovery System) are in a virtual tie for highest rank when all factors are considered, with
Alternatives 1 and 4 ranking markedly lower than Alternatives 2 and 3. The next section summarizes the
rationale for recommending one alternative among these two, highest-ranking alternatives.
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5.1 Recommended Alternative
The Benefit/Cost analysis conducted in the previous section concluded that the following two alternatives
are virtually tied with the highest Benefit/Cost Scores:
• Alternative 2 – Thermal Drying
• Alternative 3 – Thermal Drying with Heat-Recovery Furnace (energy recovery system)
The Non-monetary Benefits comparison shown in Figure 6 concluded that Alternative 3 scored the highest,
while the cost comparisons shown in Tables 12 and 13 indicate that Alternative 2 has a slightly lower NPV
than Alternative 3. There is a marked contrast, however, between Alternatives 2 and 3 when their relative
capital costs and O&M costs are compared as shown in Figures 7 and 8. Alternative 2 has a significantly
lower capital cost and significantly higher O&M cost than Alternative 3.
There are some technology and regulatory risks associated with Alternative 3 that are not associated with
Alternative 2. For example, Alternative 3 is still considered innovative technology because there is only one
other facility in North America that uses a thermal dryer with heat-recovery furnace, which is located in
Buffalo, Minnesota. Also, there may be air-emissions permitting challenges associated with Alternative 3,
which involves combustion of biosolids, which compared to Alternative 2, which only requires drying of
biosolids.
The recommended alternative depends largely on CBJ’s access to sufficient capital to fund the additional
equipment required for Alternative 3, namely the heat-recovery furnace equipment and accessories. If CBJ
has sufficient capital funds to pay for the higher capital cost of Alternative 3, then substantial annual savings
can be achieved by reduction of O&M costs associated with Alternative 3. Also, if an opportunity exists to
defray the capital costs through grant funding, Alternative 3 would be the most desirable alternative to
implement, because the investment in higher capital for Alternative 3 would substantially reduce CBJ’s
annual O&M costs.
Therefore, Alternative 3 – Thermal Drying with Heat-Recovery Furnace (energy recovery system) is the
recommended alternative for implementation.
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TABLE 8
Capital Cost Breakdown of Alternatives for MWWTP Facility Location
Capital Cost Component Alternative 1 Alternative 2 Alternative 3 Alternative 4
ABF Building Demolition $75,000 $75,000 $75,000
Thermal Dryer $2,898,000
Thermal Dryer/Energy Recovery
Furnace $5,840,000
Fluidized Bed Incineration $14,342,178
Post Dewatering sludge storage $500,000 $500,000 $500,000
Dried Product/Ash Silo $500,000 $500,000 $250,000
General solids conveyance $500,000 $500,000 $500,000
New Building $2,240,000 $2,240,000 $2,240,000
Rolling stock and equipment $1,500,000
Subtotal Construction/Installation Cost $1,500,000 $6,713,000 $9,655,000 $17,907,178
Additional Project Costs
Site Work $134,260 $193,100 $358,144
Installation (10% of equipment cost) $289,800 $584,000 $1,434,218
Plant Computer System, I&C $335,650 $482,750 $895,359
Yard Electrical $537,040 $772,400 $1,432,574
Yard Piping $335,650 $482,750 $895,359
Subtotal $0 $1,632,400 $2,515,000 $5,015,653
Other Markups
Overhead $150,000 $834,540 $1,217,000 $2,292,283
Profit $82,500 $458,997 $669,350 $1,260,756
Mobilization/Bonds/Insurance $86,625 $481,947 $702,818 $1,323,794
Contingency (30%) $545,738 $3,036,265 $4,427,750 $8,339,899
Location Adjustment Factor
(18% above 100% for CBJ)
$425,675 $2,368,287 $3,453,645 $6,505,121
Subtotal $1,290,538 $7,180,036 $10,470,563 $19,721,853
Non-Construction Costs
Permitting $55,811 $310,509 $452,811 $852,894
Engineering $251,148 $1,397,289 $2,037,651 $3,838,022
Services During Construction $776,272 $1,132,028 $2,132,234
Commissioning & Startup $465,763 $679,217 $1,279,341
Land / ROW
Legal / Admin $55,811 $310,509 $452,811 $852,894
Subtotal Non-Construction $362,770 $3,260,342 $4,754,518 $8,955,384
Total Construction Cost Estimates $3,200,000 $18,800,000 $27,400,000 $51,600,000
TM 2: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II ALTERNATIVES EVALUATION AND RESULTS
WBG090414062923ANC 17
TABLE 9
Capital Cost Breakdown of Alternatives for JDWWTP Facility Location
Capital Cost Component Alternative 1 Alternative 2 Alternative 3 Alternative 4
Incinerator Building Demolition $75,000 $75,000 $ 75,000
Thermal Dryer $2,898,000
Thermal Dryer/Energy Recovery
Furnace $5,840,000
Fluidized Bed Incineration $14,342,178
Post Dewatering sludge storage $1,000,000 $1,000,000 $1,000,000
Dried Product/Ash Silo $500,000 $500,000 $250,000
General solids conveyance $500,000 $500,000 $500,000
New Building $2,240,000 $2,240,000 $2,240,000
Rolling stock and equipment $1,500,000
Subtotal Construction/Installation Cost $1,500,000 $7,213,000 $10,155,000 $18,407,178
Additional Project Costs
Site Work $144,260 $203,100 $368,144
Installation (10% of equipment cost) $289,800 $584,000 $1,434,218
Plant Computer System, I&C $360,650 $507,750 $920,359
Yard Electrical $577,040 $812,400 $1,472,574
Yard Piping $360,650 $507,750 $920,359
Subtotal $0 $1,732,400 $2,615,000 $5,115,653
Other Markups
Overhead $150,000 $894,540 $1,277,000 $2,352,283
Profit $82,500 $491,997 $702,350 $1,293,756
Mobilization/Bonds/Insurance $86,625 $516,597 $737,468 $1,358,444
Contingency (30%) $545,738 $3,254,560 $4,646,045 $8,558,194
Location Adjustment Factor
(18% above 100% for CBJ)
$425,675 $2,538,557 $3,623,915 $6,675,391
Subtotal $1,290,538 $7,696,251 $10,986,778 $20,238,068
Non-Construction Costs
Permitting $55,811 $332,833 $475,136 $875,218
Engineering $251,148 $1,497,749 $2,138,110 $3,938,481
Services During Construction $832,083 $1,187,839 $2,188,045
Commissioning & Startup $499,250 $712,703 $1,312,827
Land / ROW
Legal / Admin $55,811 $332,833 $475,136 $875,218
Subtotal Non-Construction $362,770 $3,494,747 $4,988,923 $9,189,789
Total Construction Cost Estimates $3,200,000 $20,100,000 $28,700,000 $53,000,000
TM 2: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II ALTERNATIVES EVALUATION AND RESULTS
18 WBG090414062923ANC
TABLE 10
Annual O&M Cost Breakdown of Alternatives for MWWTP Facility Location
O&M Costs Alternative 1 Alternative 2 Alternative 3 Alternative 4
Cake Hauling Between plants $34,188 $34,188 $35,328
Truck loading of product ($20/wet ton) $142,194
Hauling of product ($20/ wet ton) $142,194 $24,533 $3,312 $3,312
Landfill of product ($215/wet ton for combined
barge/landfill)
$1,531,355
Product sales
Dryer O&M $181,942 $304,569
Incinerator O&M $380,444
Electricity $30,985 $48,153
Fuel $640,4061 $139,1662 $197,3091
Total OM $/yr $1,816,258 $912,055 $529,388 $616,392
Contingency on O&M cost (10%) $181,626 $91,205 $52,939 $61,639
Total Avg Annual OM $/yr (Current Unit Prices) $1,998,000 $1,003,000 $582,000 $678,000
1 No. 2 Fuel Oil
2 Supplemental Wood Chips
TABLE 11
Annual O&M Cost Breakdown of Alternatives for JDWWTP Facility Location
O&M Costs Alternative 1 Alternative 2 Alternative 3 Alternative 4
Cake Hauling Between plants $108,263 $108,263 $111,872
Truck loading of product ($20/wet ton) $142,194
Hauling of product ($20/ wet ton) $142,194 $24,533 $3,312 $3,312
Landfill of product ($215/wet ton for combined
barge/landfill)
$1,531,355
Product sales
Dryer O&M $181,942 $304,569
Incinerator O&M $380,444
Electricity $30,985 $48,153
Fuel $640,4061 $139,1662 $197,3091
Total OM $/yr $1,816,258 $986,130 $603,463 $692,936
Contingency on O&M cost $181,626 $98,613 $60,346 $69,294
Total Avg Annual OM $/yr (Current Unit Prices) $1,998,000 $1,085,000 $664,000 $762,000
1 No. 2 Fuel Oil
2 Supplemental Wood Chips
TM 2: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II ALTERNATIVES EVALUATION AND RESULTS
WBG090414062923ANC 19
TABLE 12
Net Present Value (NPV) Cost Estimates of the Alternatives for MWWTP Facility Location
Alternative
Number Name of Alternative
NPV of Capital
Cost
NPV of Annual
O&M Costs Total NPV
1 Maintain Status Quo $2,700,000 $32,200,000 $34,900,000
2 Thermal Drying $18,300,000 $16,100,000 $34,400,000
3 Thermal Drying with Heat‐Recovery Furnace $26,600,000 $9,400,000 $36,000,000
4 Thermal Oxidation (Incineration) $50,200,000 $10,900,000 $61,100,000
TABLE 13
Net Present Value (NPV) Cost Estimates of the Alternatives for JDWWTP Facility Location
Alternative
Number Name of Alternative
NPV of Capital
Cost
NPV of Annual
O&M Costs Total NPV
1 Maintain Status Quo $2,700,000 $32,200,000 $34,900,000
2 Thermal Drying $19,500,000 $17,500,000 $37,000,000
3 Thermal Drying with Heat‐Recovery Furnace $27,900,000 $10,700,000 $38,600,000
4 Thermal Oxidation (Incineration) $51,500,000 $12,300,000 $63,800,000
FIGURE 7
Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for MWWTP Facility
Location
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat‐Recovery Furnace
4: Thermal Oxidation
(Incineration)Net Present Value as % of Alt 1, Current Disposal Method (Lower Score is Better)O&M Cost Capital Cost
TM 2: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II ALTERNATIVES EVALUATION AND RESULTS
20 WBG090414062923ANC
FIGURE 8
Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for JDWWTP Facility
Location
TABLE 14
Benefit‐cost Score of Alternatives for MWWTP Location
Project Title
Capital & O&M
NPV
Non‐monetary
Benefit Score
Benefit‐Cost
Score
Benefit‐Cost Score
Relative to Status Quo
1: Maintain Status Quo $34,900,000 20.66 0.59 100%
2: Thermal Drying $34,400,000 26.28 0.76 129%
3: Thermal Drying with Heat‐Recovery
Furnace
$36,000,000 27.44 0.76 129%
4: Thermal Oxidation (Incineration) $61,100,000 26.28 0.43 73%
TABLE 15
Benefit‐cost Score of Alternatives for JDWWTP Location
Project Title
Capital &
O&M NPV
Non‐monetary
Benefit Score
Benefit‐
Cost Score
Benefit‐Cost Score
Relative to Status Quo
1: Maintain Status Quo $34,900,000 20.66 0.59 100%
2: Thermal Drying $37,000,000 26.28 0.71 120%
3: Thermal Drying with Heat‐Recovery Furnace $38,600,000 27.44 0.71 120%
4: Thermal Oxidation (Incineration) $63,800,000 26.28 0.41 70%
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
200%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat‐Recovery Furnace
4: Thermal Oxidation
(Incineration)Net Present Value as % of Alt 1, Current Disposal Method (Lower Score is Better)O&M Cost Capital Cost
TM 2: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II ALTERNATIVES EVALUATION AND RESULTS
WBG090414062923ANC 21
FIGURE 9
Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for MWWTP Facility Location
FIGURE 10
Benefit-Cost Scores for All Alternatives Relative to Status Quo Option for JDWWTP Facility Location
100%
129%129%
73%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
100%
120%120%
70%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
WBG090414062923ANC 1
TECHNICAL MEMORANDUM 3
Biosolids Treatment and Disposal Evaluation–Phase II Long Term Plan and Operating Strategies
PREPARED FOR: City/Borough of Juneau (CBJ), Alaska
PREPARED BY: CH2M HILL
DATE: September 4, 2014
1.1 Introduction
Objectives of this Technical Memorandum 3 (TM3) are:
1. To describe the recommended alternative in detail
2. To describe potential operating strategies for the recommended plan
3. To describe phasing alternatives for the recommended plan, with associated implementation schedules.
This TM will describe the recommended long-range biosolids management plan, based on the work
summarized in prior TMs 1 and 2, and the decisions made at Workshops 1 and 2.
2.1 Recommended Alternative
TM2 (Alternatives Evaluation and Results) summarized the methodology and results of the alternatives
evaluation, and presented additional issues to consider in selecting and implementing an alternative.
Workshop 2 was held with CBJ on July 8-9, 2014, to discuss TM2 and the results of the evaluation. CH2M
HILL made revisions to TM2 to reflect the decisions of Workshop 2, and delivered the revised draft of TM2 to
CBJ on July 16, 2014. Review comments on TM2 were received from CBJ on July 29, 2014. This section
summarizes the current status of decisions made relative to the recommended alternative and its potential
variations.
2.1.1 Results of Alternative Evaluation Workshop
The following four alternatives were evaluated in detail in TM2 and discussed in Workshop 2:
1. Continuation of the current practice of shipping dewatered biosolids from the JDWWTP and the
MWWTP by barge to Oregon for landfill disposal (also known as the “status quo” or “base case”
alternative).
2. Thermal drying of biosolids at a central facility with local disposal or marketing of the dried, Class A
biosolids product.
3. Thermal drying of biosolids followed by combustion (incineration) of the biosolids to recover heat that is
then recirculated to the biosolids drying process, thus reducing the amount of purchased fuel (thermal
drying with heat recovery).
4. Thermal oxidation (incineration) of the biosolids in a new fluidized-bed incinerator that recovers heat
from the combusted biosolids to aid in evaporation and reduce the amount of purchased fuel.
Alternatives 2, 3 and 4 were evaluated assuming one of two locations for a centralized biosolids
management facility. In the first case, the biosolids management facility is assumed to be located at the
CBJ’s Mendenhall Wastewater Treatment Plant (MWWTP). In the second case, the biosolids management
facility is assumed to be located at the Juneau-Douglas WWTP (JDWWTP). Figures 1 and 2 show the results
of the Benefit-Cost analysis and comparison of the four alternatives, assuming that the biosolids
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
2 WBG090414062923ANC
management facility is located at either the MWWTP or the JDWWTP, respectively. In this Benefit-Cost
Analysis, each alternative is compared with Alternative 1 (Status Quo) which was assigned a relative score of
100%. The relative benefits and costs of each alternative are each given 50% of the total score, with the
result that the alternative with the best combination of low costs and high benefits shows the highest total
Benefit-Cost score.
FIGURE 1
Benefit-Cost Scores of Alternatives 1-4 with Biosolids Management Facility at MWWTP
FIGURE 2
Benefit-Cost Scores of Alternatives 1-4 with Biosolids Management Facility at JDWWTP
In each case shown above, Alternatives 2 and 3 both result in higher Benefits-Cost scores than the Status
Quo, by significant percentages of 26-39% higher scores, while Alternative 4 shows a significantly lower
Benefits-Cost score. The differences between the Benefits-Cost scores of Alternatives 2 and 3 are minimal
and smaller than the accuracy of the estimating tool.
Another factor that plays heavily into the decision-making process is a comparison of Net Present Worth
(NPW) between alternatives, as shown in Figures 3 and 4. In these figures, the capital and O&M costs are
further separated into annual operations and maintenance (O&M) and capital cost components. This
100%
129%129%
73%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
100%
120%120%
70%
40%
60%
80%
100%
120%
140%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat-Recovery Furnace
4: Thermal Oxidation
(Incineration)
Benefit-Cost Scores
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
WBG090414062923ANC 3
comparison shows that Alternatives 2 and 3 both have slightly lower NPW’s than Alternative 1 (Status Quo).
Although Alternative 3 has a slightly higher NPW than Alternative 2, its O&M cost component is significantly
lower.
FIGURE 3
Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for MWWTP Facility Location
FIGURE 4
Net Present Value of Capital and O&M Costs for All Alternatives Relative to Status Quo Option for JDWWTP Facility Location
Another important factor in the comparison of alternatives is “carbon footprint,” which is an assessment of
the potential for greenhouse gas (GHG) emissions associated with each alternative. A basic estimation of
direct (Scope 1) GHG emissions associated with each alternative indicates that Alternative 3 has a
substantially lower estimate of GHG emissions (i.e., carbon footprint) than Alternative 2. This is primarily
because Alternative 2 depends on a fossil fuel (No. 2 heating oil) to dry the biosolids, while Alternative 3
creates a renewable fuel (dried biosolids pellets) that can be combusted as a fuel source, and renewable
wood chips are used as a fuel supplement if the fuel value of dried biosolids is not enough to drive the
drying process.
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat‐Recovery Furnace
4: Thermal Oxidation
(Incineration)Net Present Value as % of Alt 1, Current Disposal Method (Lower Score is Better)O&M Cost Capital Cost
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
200%
1: Maintain Status Quo 2: Thermal Drying 3: Thermal Drying with
Heat‐Recovery Furnace
4: Thermal Oxidation
(Incineration)Net Present Value as % of Alt 1, Current Disposal Method (Lower Score is Better)O&M Cost Capital Cost
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
4 WBG090414062923ANC
When all factors were taken into consideration including non-monetary criteria such as carbon footprint,
capital costs, and annual O&M costs, Alternative 3 – Thermal Drying with Heat-Recovery Furnace, was
selected as the most desirable long-term biosolids management alternative for Juneau going forward.
2.1.2 Description of Recommended Alternative
The recommended alternative utilizes thermal drying to substantially decrease the water content of the
sludge prior to thermal oxidation. With the addition of a furnace, energy is recovered by using the dried
biosolids as the primary fuel for the furnace, which in turns heats the air that dries the biosolids. Additional
energy is recovered by a heat exchanger system which extracts heat from the drying process. The final
product of the dryer/furnace combination is an inert ash at > 98% solids content.
Wood pellets would be needed to supplement the dried biosolids as fuel for the furnace under most
operating conditions, because the dried biosolids do not always provide enough heat to dry the biosolids.
The dryer could also operate using only wood pellets as fuel, and produce dried biosolids pellets at 90%
solids for other beneficial uses. Finally, the dryer could use an oil burner as its heat source rather than a
furnace, but in that case, No. 2 heating oil would be the only fuel used for providing the heat to dry to the
biosolids, and there would not be an option for using dried biosolids or wood pellets as fuel.
The recommended alternative therefore includes a furnace that will combust biosolids and wood pellets to
produce heat for drying the biosolids, thereby avoiding the use of fossil fuels in the heat drying process.
2.1.2.1 Belt Dryer
The type of dryer upon which the recommended alternative is based is a belt dryer, chosen because it was
the best fit among other dryer alternatives for CBJ’s projected biosolids loading rates. The belt dryer is also
one of the safest dryers on the market because it operates at the lowest temperature range of available
biosolids dryers.
Belt dryers use direct contact of circulating hot air with wet solids extruded onto and conveyed by a slowly
moving horizontal belt housed in a metal enclosure. The wet material moves through several drying
chambers, where the moisture is released into the circulating air. After passing through the drying
chambers, the dried solids fall from the belt into a hopper and are conveyed to a loading or storage facility.
Each drying zone has its own circulating fans and air temperature control. Excess moisture is removed from
the air stream in a saturator. Heat for the air circulation loop in each zone is provided in a heat exchanger by
indirect contact with steam, hot water, thermal oil, or hot air serving as the heat source. The drying
temperatures are typically controlled at approximately 300°F at the belt entry and at 210°F at the belt
discharge. The solids are typically heated to 170°F. The lower drying temperature usually produces a less
odorous exhaust stream, and the drying process is less prone to accidental combustion than rotary drum
dryers, which operate at much higher temperatures.
Dried biosolids produced by the dryer are composed of fragments that are non-uniform in shape, with sizes
between 1 and 10 mm across. A screen is sometimes used to produce a more uniform product size. A
pelletizer must be added if smaller pellets of uniform size are desired. Since the sludge is not excessively
moved in this system, dust formation is reduced in the dryer itself, although dust may form in subsequent
handling of the dried product. Figure 5 presents a schematic diagram of a typical belt dryer system.
Belt dryers are available from Andritz, Kruger, and Huber. Kruger belt dryers were first installed in Europe in
1995, and Andritz’s first belt dryer was installed in Europe in 2002. At present there are at least twenty
Kruger and about the same number of Andritz belt dryers either in operation or development worldwide,
while Huber follows with approximately ten belt dryer installations in operation or development worldwide.
Of the worldwide installations, Kruger has five belt dryer installations in the USA, Huber has two belt dryer
installations in the USA, and Andritz has no USA belt dryer installations to date.
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
WBG090414062923ANC 5
FIGURE 5
Belt Dryer Schematic Diagram
2.1.2.2 Heat-recovery Option for Belt Dryer
The belt dryer operating with a heat-recovery furnace has reduced operational costs when compared to the
dryer alone. The dryer alone has a much higher external-fuel requirement, while the heat-recovery furnace
can provide most of the heat needed for drying by combustion of the dried product with the heat recovered
from combustion. Dewatered solids are stored in the cake-storage silo until there is enough to conduct a
dryer run. Solids are pumped into an extrusion device and distributed on the belt. The cake solids are dried
with hot air from the furnace which, in this case combusts dried biosolids.
The heat-recovery option requires a higher level of maintenance and also requires disposal of ash. These
elements are offsetting but result in significantly lower O&M costs for the heat-recovery option when
compared with the standard belt dryer. The heat value of the dried biosolids is a function of the volatile
solids content of the solids, and has a large impact on the predicted operating cost. Based on the volatile
solids content of 85-90% found at CBJ’s WWTPs, the dried sludge will provides at least 80% of the heat
requirement of the dryer. Should the total solids content of the dewatered solids increase from current
values, the heat-recovery furnace may provide all of the heat requirement of the belt dryer.
Supplemental fuel for the furnace is still needed for the thermal dryer with heat-recovery furnace, because
of the relatively high water content of biosolids produced by the belt filter presses at JDWWTP and
MWWTP. Heat is recovered from the water in the dryer exhaust and used to preheat the biosolids going into
the dryer, but the air from the furnace provides the primary source of heat to the dryer. The dryer and
furnace exhausts are scrubbed to remove any pollutants and discharged to the atmosphere. The resulting
ash can be mixed with soil to use in landfill cover or used as a substitute for fly ash in concrete production. If
the dried pellets are not incinerated, they may be used as fertilizer or soil amendment.
Each of the belt dryer manufacturers listed above offers a heat-recovery furnace option with its belt dryer,
and each of them reports at least one installation of a belt dryer with heat-recovery furnace in Europe. Only
one of the three belt-dryer manufacturers has a dryer with heat-recovery furnace operating in the USA,
Dewatered
Biosolids Cake
Feed Hopper
Biosolids Mixer / Conveyor
Biosolids Belt Dryer Product
Screen
Product
Cooler
Condenser Air Heat
Exchanger
Storage
Silo
Condensate
Cooling Water
Recycle Air
Recycled Dried Solids
Dried
Biosolids
Dried Biosolids
No. 2 Fuel
Oil
Hot Air
Air Exhaust to Air
Pollution Control
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
6 WBG090414062923ANC
however, and that is Kruger. The City of Buffalo, Minnesota, has operated a Kruger belt dryer with heat-
recovery furnace since 2008, and it is sized for approximately 3 MGD of wastewater flow, similar to Juneau.
Figure 6 illustrates Alternative 3 – Thermal Drying with Energy Recovery Furnace, based on the Kruger
BioCon-ERS process, upon which most of the technical and cost-estimating information was obtained for
Alternative 3.
FIGURE 6
Simplified schematic Diagram of Alternative 3 – Thermal Drying with Energy Recovery Furnace, Based on Kruger
BioCon-ERS Model
2.1.3 Planning and Siting Recommendations
There are two potential site locations for CBJ’s biosolids drying facility, the MWWTP or the JDWWTP. The
MWWTP produces almost 80% of CBJ’s biosolids, so would be the logical choice for siting a central biosolids
management facility to reduce the extent of biosolids hauling. However, the site at MWWTP is more
constrained, and the Mendenhall Valley where the MWWTP is located is currently a non-attainment area for
air emissions, which would likely increase the cost of permitting and air-emissions technology at the
MWWTP. The JDWWTP site has more available space and a wider buffer from its adjacent properties, and is
not as sensitive as the MWWTP site with respect to its air-permitting requirements.
Furnace
TM 3: BIOSOLIDS TREATMENT AND DISPOSAL EVALUATION–PHASE II LONG TERM PLAN AND OPERATING STRATEGIES
WBG090414062923ANC 7
The advantages and disadvantages of locating new facilities at the MWWTP or the JDWWTP are summarized
below in Table 1:
TABLE 1
Advantages/Disadvantages of Biosolids Facility Location
Comparison Criteria Mendenhall WWTP Juneau-Douglas WWTP
Sludge Transported Annually 1710 wet tons 5413 wet tons
Distance to Landfill (Disposal Site) 4 miles 7 miles
Air Emissions/Permitting Issues Complex (close neighbors,
Mendenhall Valley non-
attainment)
Not as complex (industrial district, had
prior air emissions permit)
Infrastructure Needs Need new building, must
demolish existing building,
constrained site
May be able to reuse part of
Incineration/Dewatering Building,
more space available
Construction Timeline Likely longer due to restricted
site access and more complex
permitting
Likely shorter due to easier site access
and less complex permitting
Resident/Neighbor Impacts Nearby commercial and
residential neighbors on all
sides
Industrial area, no nearby residences,
near cruise ship docks and 1 mile from
downtown Juneau
NPV of Capital Costs $26.6 million $27.9 million
NPV of O&M Costs $9.4 million $10.7 million
Locating a new biosolids drying facility at the MWWTP appears to be less costly than locating a biosolids
drying facility at the JDWWTP at this point, because nearly 80% of CBJ’s biosolids are produced at the
MWWTP. Therefore, the JDWWTP facility capital cost includes larger bins for storing imported solids, and its
O&M costs reflect higher volumes of dewatered solids that have to be transported from MWWTP to
JDWWTP.
The JDWWTP facility location has several non-monetary advantages over the MWWTP location, however. It
does not have neighbors in close proximity like the MWWTP does. The MWWTP neighbors have periodically
filed complaints related to odors from the MWWTP. It is believed that the JDWWTP would be less subject to
odor and nuisance complaints than the MWWTP, due to its location in an industrial zone next to a shipping
dock and more land available for a buffer zone. Also it is believed that air emissions permitting may be less
complex at the JDWWTP because a permitted incinerator previously operated on the site, and the MWWTP
is in a non-attainment area for air particulates, potentially making an air emissions permit at MWWTP more
stringent and difficult to obtain.
Figure 7 indicates where a new thermal drying facility with energy-recovery furnace could be located on the
JDWWTP site. The system’s space requirements are approximately 95 feet long by 75 feet wide. It is
advantageous to locate the drying facility as close as possible to the dewatering equipment. The existing
dewatering equipment at JDWWTP, which would remain in place, is represented by the small rectangle in
the bottom left corner of the existing incinerator building. The new thermal drying facility is located just to
the right of the existing dewatering equipment in Figure 7. The portion of the existing building that houses
the de-commissioned incinerator would likely have to be demolished, and the new thermal drying facility
installed inside a new building in its place, as shown in Figure 7.
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FIGURE 7
Potential Location of Thermal Dryer with Energy Recovery Furnace at the JDWWTP Site
Figure 8 indicates where a new thermal drying facility with energy-recovery furnace could be located on an
aerial photo of the MWWTP site. The blue line represents the approximate property boundary of the
MWWTP and the new thermal drying facility is shown at the location of the existing ABF building. The
building housing existing dewatering equipment at the MWWTP is shown in the lower right of the new
thermal drying facility and would remain. The existing ABF Building at the MWWTP would need to be
demolished to provide space for the new thermal drying facility, to be installed in a new building in its place,
as shown in Figure 8.
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FIGURE 8
Potential Location of Thermal Dryer with Energy Recovery Furnace at the MWWTP Site
A preliminary general-arrangement drawing of the recommended thermal drying facility with energy-
recovery furnace is shown in Figure 9, which also indicates which equipment would be provided by the
drying system vendor and which equipment would be provided by other parties (designated “by others”).
3.1 Recommended Operating Strategies
This section describes operating strategies of five, similar belt-dryer installations in the USA, and provides
recommendations for operating strategies at CBJ’s future biosolids drying facility.
3.1.1 Operating Strategies at Similar Facilities
The operators of Kruger’s five belt-drying facilities in the USA were contacted recently to determine how
they operate their facilities, how long they have been operating, the typical weekly operating hours, the fuel
source for the dryer, and the use of the dried product. Table 2 provides a summary of the findings from
those belt-drying facilities.
None of the operating belt-dryer facilities reported any significant, unplanned downtime since startup. The
heat-recovery furnace at Buffalo, MN, is currently out of service while ash-handling conveyors are being
replaced; however, the belt dryer in Buffalo continues to operate on its normal schedule.
New Biosolids
Thermal
Dryer/Furnace
Building Existing Dewatering
Building
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FIGURE 9
General Arrangement Drawing of Thermal Dryer with Energy Recovery Furnace
TABLE 2
Summary of Operating Belt Drying Facilities in the USA (dryers manufactured by Kruger)
Facility
Location
Year of
Start-up
WWTP
size,
MGD
Production
(tons/year
dried solids)
Dryer Capacity
(wet pounds
per hour) Fuel Source
Normal Operating
Schedule
Use of
Product
Mystic Lake,
MN
2006 0.64 367 1,100 Natural Gas 8 hrs/day,
5 days/week
Fuel for
power
plant
Buffalo, MN1 2008 3.0 1,512 3,300 Dried
Biosolids (no
backup fuel)
24 hrs/day,
7 days/week while
solids are available
Ash is
landfilled
LeSeuer, MN 2008 0.9 405 1,663 Natural Gas 24 hrs/day,
7 days/week while
solids are available
Given to
farmers
New Prague,
MN
2010 2.5 1,190 6,083 Natural Gas 48-96 hrs straight,
every other week
Given to
farmers
Alderwood,
WA
2013 6.0 1,036 3,300 Natural Gas 10 hrs/day,
5 days/week
Sold to
fertilizer
vendor
1 Buffalo, MN, is the only belt drying system with a heat-recovery furnace operating in the USA to date.
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The belt-drying facilities in Buffalo and New Prague, MN are oversized for their current loading rates.
Coincidentally, both facilities have large volumes of pre-dewatering solids storage available. Consequently,
they can store biosolids for 2-4 weeks while building up inventory for dewatering and drying operations.
Once these facilities start up, they operate around-the-clock until the solids inventory is depleted. The
Buffalo, MN, facility tends to operate in this manner for one period a month, and its operating period
generally lasts about 10-12 days. The New Prague, MN, facility has less solids-storage capacity and so
operates more frequently, typically for 48-96 hours each week.
The New Prague and Le Seuer facilities in Minnesota operate their belt dryers 24 hours per day when they
have sufficient solids inventory, but their facilities are only staffed 8 hours per day. During the unstaffed 16
hours per day the belt dryers operated unattended, and the alarm functions on the belt dryers are
computerized to automatically dial the telephone number of the operator on call. Both New Prague and Le
Seuer reported no problems with unattended operation of their belt dryers in this manner. Buffalo, MN,
keeps one operator at the WWTP all hours of the day, because it is a regulatory requirement for a WWTP of
its size. Kruger reported that several of its dryers with energy-recovery furnaces in Europe operate
unattended overnight, with telephonic alarm service to the operator-on-call.
3.1.2 Recommended Operating Strategies for CBJ
Based on CH2M HILL’s survey of other belt dryers operating in the USA, it is recommended that CBJ plan to
operate its belt dryer and heat-recovery furnace around-the-clock when it has sufficient solids inventory,
similar to the mode of operation at Buffalo, MN. Both the JDWWTP and MWWTP appear to have sufficient
pre-dewatering solids storage capacity, although the JDWWTP has more storage volume in its aerobic
digestion basin than the MWWTP has in its settled-solids holding tank.
Based on preliminary calculations, CBJ can store at least a week’s inventory of waste solids in liquid form at
the JDWWTP, which can be used to operate dewatering and drying/combustion facilities around-the-clock.
Biosolids storage is not available in these volumes at the MWWTP, so another aerated storage tank may
need to be added to provide a week’s worth of storage capacity at the MWWTP. It is also recommended
that cake storage facilities be constructed at JDWWTP of sufficient volume to store one week’s worth of
dewatered cake solids from the MWWTP. Cake storage facilities are more costly to build and operate than
liquid storage tanks, which is why the estimated capital costs for thermal drying facilities at the JDWWTP are
slightly higher than at the MWWTP.
Based on CH2M HILL’s survey findings regarding attended or unattended operation of belt dryers, with and
without heat-recovery furnaces, it does not appear that full-time attended operation of a drying/heat
recovery facility would be necessary for CBJ. Similar to operational procedures at Le Seuer and New Prague,
MN, unattended operation of the dewatering and drying systems would be possible, provided that system
monitoring can be done remotely via internet or telephone. Control systems for CBJ’s thermal drying
facilities would need to be designed with special features for remote operation. Similar remote monitoring
and control systems are in operation at a number of other belt drying facilities, as noted above.
Automated storage facilities of sufficient capacity for liquid waste solids, dewatered cake solids, dried
biosolids, and biosolids ash will need to be designed and provided to allow for unattended operation. Truck
load-out facilities for the dewatered cake, dried biosolids, and ash will also need to be provided. The truck-
loading facilities will not require remote operating capability, since truck loading activities are undertaken
only when staff are onsite. Transport of dewatered biosolids will be required from one of the WWTPs to the
other WWTP where the thermal drying facilities are located. It is recommended that truck hauling be done
at night to minimize traffic problems and odor complaints, and decrease hauling time.
In summary, the recommended operating strategy for CBJ’s new biosolids drying and energy-recovery
facilities is very similar to the current operating strategies for similar drying facilities in Buffalo, Le Seuer, and
New Prague, MN. For this reason it is considered important that CBJ schedule site visits to view these three
existing belt drying facilities in operation.
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4.1 Project Phasing and Scheduling Options
This section describes how the project would be implemented and phased under two potential scenarios:
1. Design of belt drying system and heat-recovery furnace in a single capital project using a traditional
design-bid-build approach.
2. Construction of drying and heat-recovery systems in a single capital project using progressive design-
build delivery approach
Based on discussion in Workshop 2, CBJ would prefer to implement Option 1 above, because it provides
more time to obtain grant or loan assistance for the construction project. Option 2 would be implemented if
there is a need to accelerate the project schedule by up to nine months.
The next section describes the anticipated project schedules under each of the two options listed above.
4.1.1 Anticipated Project Schedules under Two Delivery Options
The CBJ would prefer to implement the biosolids drying/heat-recovery facilities with a traditional design,
bid, build delivery approach, with owner pre-purchase or pre-selection of the drying system. Early selection
and purchase of the drying and heat-recovery systems would enable detailed design to proceed while the
drying equipment is being designed and manufactured, which will lessen the impact of long lead times
required for manufacturing and delivery of the drying and heat-recovery equipment.
Table 3 presents an anticipated, general project schedule under the Option 1 scenario above, in which the
belt drying system and heat-recovery system would be designed and installed together as part of the same
capital project.
It may be possible to accelerate the schedules shown in Table 3 by up to nine months by using an alternative
delivery method such as progressive design-build. Under progressive design-build delivery, the project
schedule would be compressed in the design and construction phases, since those phases would be
delivered by the Design-Build Contractor. An anticipated project schedule under progressive design-build
delivery is shown in Table 4.
TABLE 3
Anticipated Project Schedule under Option 1: Construction of Drying and Heat-Recovery Systems in a Single Capital
Project
Activity
Year 2014 2015 2016 2017
Quarter 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd 3rd
Preliminary Engineering
Project Funding1
Design & Permitting
Dryer/Furnace Procurement &
Submittals
Dryer/Furnace Manufacturing &
Delivery1
Bidding and Construction2
Startup2
Full-scale Operations
1 The dryer/furnace manufacturing/deliver and construction schedule are tied to project funding availability.
2 Construction phase ends at substantial completion; final completion would occur after successful startup.
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TABLE 4
Anticipated Project Schedule under Option 2: Construction of Drying and Heat-Recovery Systems in a Single Capital
Project using Progressive Design-Build Delivery Approach
Activity
Year 2014 2015 2016 2017
Quarter 4th 1st 2nd 3rd 4th 1st 2nd 3rd 4th 1st 2nd
Preliminary Engineering
Project Funding & DB Contractor Selection1
Design, Permitting, and Construction2
Dryer/Furnace Procurement & Submittals
Dryer/Furnace Manufacturing & Delivery1
Startup2
Full-scale Operations
1 The dryer/furnace manufacturing/deliver and construction schedule are tied to project funding availability.
2 Construction phase ends at substantial completion; final completion would occur after successful startup.
Startup would begin earlier but take longer in Option 2 than in Option 1. It is expected that discussions and
decisions regarding the desired option and delivery method for the project would occur during the
preliminary engineering and project funding phases of the project, at which point one of the delivery
options described above will be chosen.
4.1.2 Recommended Next Steps
In order to keep the project on schedule, CBJ is expected to endorse the Final Report and recommendations
of this Phase II Biosolids Process Evaluation in the early fall of 2014. Site visits to similar biosolids belt-drying
and heat-recovery facilities could also be conducted in the fall of 2014.
The scoping and negotiation of preliminary engineering and permitting phases of the project could be
accomplished in October 2014, allowing preliminary engineering to get underway in November 2014.
Preliminary engineering would also include the initiation of project funding and permitting activities.
If these initial project activities proceed as outlined above, then it is predicted that one of the two potential
delivery options discussed above could be implemented according to the schedules shown in Tables 3 or 4.