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ALASKA POWER AUTHORITY -
BEST MANAGEMENT PRACTICES MANUAL
LIQUID AND SOLID WASTE MANAGEMENT
February 1985
Prepared by Frank Moolin &Associates,Inc.
under contract to Harza-Ebasco
Susitna Joint Venture
ARLIS
Alaska Resources
Library &Information Services
Aulchorage,AJaska
....
PREFACE
This manual is one of a series of "best management practices"manual to be used
iln the design,construction,and maintenance of Alaska Power Authority projects.
It represents a coordinated effort involving federal,state and local government
agencies,and special interest groups.
The Alaska Power Authority intends that applicable gUidelines and state-of-the-
art techniques contained in the manuals will be incorporated where appropriate
into the contractual documents for projects constructed,maintained,or operated
by or under the direction of the Alaska Power Authority.
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TABLE OF CONTENTS
PAGE
PREFACE
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CHAPTER 1 -INTRODUCTION 1
....CHAPTER 2 -LIQUID WASTE MANAGEMENT 2
2.1 PROJECT PARAMETERS 2
2.2 LIQUID WASTE STREAM CONSTITUENTS 7
2.2.1 Classification 7
2.2.2 Wastewater Sources and Strengths 9
2.2.2 1 Water Treatment Backwash 9
2.2.2.2 Domestic Waste 10
2.2.2.3 Construction Wastewater 20
2.2.2.4 Maintenance and Operation 22
2.3 CONCEPTUAL CAMP LAYOUT,COLLECTION AND
TREATMENT SYSTEM 23
2.3.1 Water Supply Requirements 23
2.3.2 Wastewater Collection and Treatment
Facilities 23
2.4 DESIGN OF COLLECTION SYSTEMS 25
2.4.1 Characteristics by Type of Camp 25
2.4.1.1 Exploratory and Fly Camps 25
~2.4.1.2 Small and Intermediate Camps 27
2.4.1.3 Intermediate and Large Camps 28
2.4.2 Collection Systems 30
2.4.2.1 Conventional Gravity Collection lines 32
2.4.2.2 Pressure Sewage Collection Systems 37
2.4.2.3 Vacuum Sewage Collection Systems 40
2.4.2.4 lift Stations 42
2.4.2.5 Force Mains 45
2.5 DESIGN OF TREATMENT SYSTEM 45
2.5.1 Exploratory and Fly Camps 49
2.5.2 Small and Intermediate Camps 52
2.5.3 Intermediate and Large Camps 56
.....2.5.3.1 Pre-treatment 58
2.5.3.2 Temporary Wastewater Storage 60
2.5.3.3 Flow Equalization 61
2.5.3.4 Primary Treatment 61
2.5.3.5 Secondary Treatment 62
ARLIS
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Alaska Resources
Library &Information Services
~~chorage,AJaska
2.5.3.6 Disinfection 79
2.5.3.7 Sludge Thickening 81
l"""2.5.3.8 Sludge Digestion and Disposal 82
J 2.5.3.9 Effluent Disposal 82
CHAPTER 3 -SOLID WASTE MANAGEMENT 85
3.1 TYPES OF WASTES 88
3.2 TREATMENT ALTERNATIVES 90
3.2.1 Incineration 90
3.2.2 Landfill 92
3.2.2.1 Site Selection and Design 97
3.2.2.2 Advantages and Disadvantages 112
3.2.3 Reclamation for Reuse 113
3.2.4 Salvage 115
~3.2.5 Special Treatment 115
3.3 AT-SOURCE HANDLING 116
F>
3.4 TRANSPORT OF SOLID WASTES 117
3.5 OCCUPATIONAL SAFETY AND HEALTH 117
CHAPTER 4 -REGULATORY ANALYSIS 120
REFERENCES
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TABLE
LIST OF TABLES
PAGE
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1 Liquid Waste Treatment Variables 3
2 Camp Generated Cantaminants 8
3 Typical Average Per Person Sewage Flow 12
4 Camp Water Use and Wastewater Characteristics 13
5 Typical Wastewater Design Parameters in
Canada and USA 14
6 Institutional Sanitary Facilities in Cold Climates 15
7 Damestic Sewage Sources 16
8 Army Field Bases 16
9 Estimated Sources of Sewage Pollutants 17
10 Raw Sewage Temperature at Treatment Facil ity 21
11 Characteristics of Wastewater Collection Systems 26
12 Types of Lift Stations 43
13 Comparison of Wastewater Treatment Systems for
C~ps %
14 Wastewater Disposal -ADEC Guidelines 53
15 Performance of Extended Aeration Plants
Treating Camp Wastewater 68
16 Suggested Design Criteria and Operating
Requirements for Extended Aeration Plants
Treating Camp Wastewater 69
17 Performance of RBC Plants Treating Concentrated
Wastewater 73
18 Tentative Design Criteria and Operating
Requirements for RBC Plants Treating
Camp Wastewater 74
19 Summary of Design Parameters for PIC Unit 78
20 Chemicals Used in Wastewater Treatment 80
21 Solid Waste Disposal Techniques 91
22 Application of Soil·Information -Daily
Cover for Landfill 99
23 Application of Soil Information -Sanitary
Landfill (Trench)100
24 Application of Soil Information -Sanitary
Landfill (Area)101
25 Daily and Final Cover Material Requirements 102
26 Permissible Velocities for Bare Earthen Channels 105
27 Roadway Soil Characteristics 107
28 Equipment Selection Guide for Multiple Unit Sites 111
29 Typical Data on Vehicles Used for the Collection
of Solid Wastes 118
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FIGURE
. 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
LIST OF FIGURES
Typical Sewer and Water Bedding Details
Sewer Wall Connection
Sewer Floor Connection
low Cost Treatment Systems
High Cost Treatment Systems
Schematic of Extended Aeration Process
Schematic of Rotating Biological Contractor
Schematic of P/C Treatment Plant
Permafrost in Alaska
Criteria for Waste Management Analysis
Typical landfill Disposal Site
Sanitary landfi11ing -Area Method
Sanitary landfilling -Ramp Method
Sanitary landfil1ing -Trench Method
Soils Suitable for Cover Material
Sectional View of a Sanitary landfill
Incinerator for Energy Recovery
PAGE
34
35
36
50
57
67
72
77
87
89
93
94
95
96
103
110
114
CHAPTER 1 -INTRODUCTION
This manual has been prepared by the Alaska Power Authority as one of a series
of best management practices (BMP)manuals for projects constructed or operated
by the Power Authority in Alaska.The ultimate goal of this manual on liquid
and solid waste management is to assure that Power Authority waste management
~activ·ities are conducted in an efficient and cost-effective manner in compliance
with applicable federal,state and local laws.
This manual was prepared in recognition of the fact that waste management
tl~chniques must relate to an infinite variation in environmental conditions.
This manual thus sets forth a wide range of liquid and solid waste management
practi'ces.Not all techniques will be appropriate for a particular site.In
addition,federal,state,and local laws may impose specific requirements on
particular Power Authority projects or activities.This manual is not a substi-
tute for case-by-case identification and compliance with all laws and regula-
tions applicable to the construction and operation of Power Authority projects.
{""'"This manual addresses liquid and solid wastes:what they are,how they are
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collected,and how they are treated.Chapter 2 discusses liquid wastes and
Chapter 3 discusses solid wastes.Regulatory authorities and agencies are
listed in Chapter 4.While hazardous materials and hazardous wastes,as defined
by either EPA or Alaska regulations,are mentioned in this manual as possibly
used at or generated from a Power Authority project,discussion of the special
handling required for these materials ;s contained in a companion 8MP manual
entitled "Fuel and Hazardous Materials.1I
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CHAPTER 2 -LIQUID WASTE
This chapter discusses liquid waste:what is it~how is it collected,and how
is it treated in a chrono 1ogi ca 1 and order of magnitude approach.Smaller
systems,such as those used at short.;.term exploratory or fly camps,are
d'iscussed before larger systems used at long-term camps.The evolution of most
projects goes through a similar evolution of size and duration.
Some of the variabl es acting in a waste treatment design have been grouped in
Table 1 to facilitate discussion in terms of phasing the design effort;identify-
ing levels of complexity;placing relative costs for system construction,
operation and maintenance;and evaluating the projected degree of treatment.
2,,1 PROJECT PARAMETERS
On many occasions,a project is either a later phase or a repeat of a
similar effort in a new location.Even though it does not appear such at
the outset,there are sometimes enough dissimilar ingredients so that the
same application of technology does not yield success.
Design of treatment facilities for liquid wastes should not be an isolated
design procedure developed from data supplied by others.An environmental/
sanitary engineer should be an integral member of the project team from the
early stages.The following list presents typical projects tasks that
should have participation or review from an environmental/sanitary engineer.
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TABLE 1
lIQUID WASTE TREATMENT VARIABLES
CAMP SIZE &DURATION
TYPE
Exploratory
Short Term
Intermediate
long Term
NUMBER OF
RESIDENTS
3 to 50
3 to 50
50 to 300
300 to 4000
YEARS OF
DURATION
variesoto10
3 to 10
10 to 30
NOTE:Residents and
duration can be found in
numerous combinations.
Combination
truck &airplane
Limited trucking,
airplane or
barge likely.
Airplane or
barge.
Supply
Transport
System
Truck
Truck
Camp system
May require
haul in or
camp supply.
Camp system
May require
camp system
or haul out
100 to 160
160 or more
160 or more
Remote
Wilderness
Remote Arctic
Wilderness
LOCATION COMPLEXITY
(Assumes coal,gas or hydro power project)
Miles
Distant From
Alaska Major Supply &
Project Distribution Waste Water
1Tlo~c~a~t;.;,.io.;;,;n~..,..;;C~e~nt,;,;ei?rr--__..,T~r:reTatm~e_n_t -iiS~upply
Urban 0 to 30 Public Pu6Tic
Suburban 30 to 100 Combination or Combination
camp camp
Camp system camp system
TYPE
COllECTION SYSTEMS
DESCRIPTION
".....,
honey buckets
pit toilets
tank trucks
sewers in ground
utiliducts above ground -
or below ground
piping in utilidors
above ground or in
ground
pump stations
individual collection at generation source
disposal site at out-house
collects from storage tanks or buckets
where climate and soils permit pipe in
trenches
cold climates require insulated pipe systems
arctic climates require pipe chases heated
and insulated
TREATMENT SYSTEMS
Field Tested
small camp
short duration
haul to dump station or connect to public system
land disposal (absorption field)
seepage pi,ts
existing swamps,ponds or lakes (become lagoons)
man-made facultative lagoons
physical/chemical treatment
activated sludge {extended aeration)
rotating biological contactors
incineration of sludge
Need Additional Study
surface application of wastewater
o spray irrigation
o surface injection into plowed furrows
aerated facultative lagoons
aerobic sludge digesters
anaerobic sludge digesters
composting of sludge with shredded paper and garbage
TYPICAL PROJECT TASKS
o Exploratory survey
o Exploratory core boring
o Exploratory geology and soils sampling
o Stream flow monitoring
o Quality and quantity of water supply source
o Identification,classification and quantification of flora and
fauna
o
o
o
o
o
Route selection of haul roads and material storage areas
Final siting of the structure (earth dam,concrete dam,coal
fired generator,gas fired generator,etc.)and appurtenances
Design of the structure
Siting of early stage and final support facilities (water supply
for camp, camp,waste treatment facility,shops,power and heat
sources,fuel and supply depots)
Design of support facilities
o Permitting of support facilities
o Operation and maintenance of support facilities
o Construction of project structures
o Removal of support facilities
o Site cleanup,restoration and revegetation
o Maintenance and operation of permanent or long-term facilities
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o Monitoring for the long term (defined in the permit)all'land-
fills,waste dumps and lagoons for possible pollution after
covering
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The environmental/sanitary engineer shoul d be famil iar with conceptual
design drawings and how the project is to be situated on the premises,
including such features as approximate limits of work,excavation,material
storage,sedimentation and erosion control.Comparing topographic features
\'jlith the limits of work and property lines will aid in determining what
areas are available for camp siting and,therefore,the placement of
adequate wastewater collection and treatment systems.Studying the
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topography,geology,meteorology,surface and groundwater records of the
area will assist in making prel iminary judgements as to the best location
and orientation of dwelling units,supply and collection lines,pump
stations,treatment and discharge locations.
The projected phases of development and related camp populations including
any provisions for overlapping of staff at shift change and vacation will
be needed to calculate peak loading.Early exploration may have as few as
5 to 10 men in a drilling operation moving nomadically through the project
area and never staying more than a few days at anyone location.First-
phase camp erection will see several more men and concentrations of mater-
ials and equipment stockpiled in various locations.Large projects can
have upwards of 3000 men at peak work schedules,all of whom are housed at
a single location.Treatment systems must be flexible to take the surges
and droughts which can and do occur.
The actual selection of distribution,collection,and treatment facilities
is extremely dependent upon how quickly they must be operational and how
soon they need to be unpl ugged and moved on.Long-term fad 1iti es can be
built with an eye to efficient operation (low power consumption),durable
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semi-perma.nent materials,and efficient design based upon a more reliable
projection of demand.Short-term portable facilities are more controlled
by the results needed than the cost to get those results.Some parts of
the system such ·as pumps may be actually disposables.The challenge to the
design engineer is to obtain the correct mix of both while considering the
remoteness of the camp and difficulty of resupply.
J~n evaluation of total project cost is reasonable if one alternative is
compared to another.Actual treatment costs may be incidental and of
"little consequence due to environmental restraints and total project value.
A team effort,including input from federal and state agencies,will be
needed to establish reasonable limits of treatment.On-site population and
construction cost of the project are the primary factors needed to estimate
conceptual treatment costs and their percent of the total picture.
Comparison with similar projects and effluent requirements can be a guide
to the cost effectiveness of a given approach.
J~review of project permit requirements is also important at the planning
stage.Applicable regulations and permitting requirements may determine
the kind of waste treatment measures and facilities selected for individual
projects.The following are i~portant factors that should be an integral
part of Power Authority waste management project planning:
o Identify project goals and describe proposed construction and
other activities to implement goals .
o Determine projects impact on environment.
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o Identify statutes,regulations and agencies which regulate either
the proposed activity or its impacts.In particular,determine
whether existing Power Authority permits control the activities
or impacts involved.
o Compare burdens imposed by regulations and/or permits for
proposed activities and alternatives (including costs associated
with modifying activities to reduce or eliminate requirements).
o Develop and implement permitting strategy to obtain timely
issuance of permits.
2.2 !.IQUID WASTE STREAM CONSTITUENTS
2.2.1 Classification
The types of liquid substances or wastes anticipated at a Power Authority
project site are listed in Table 2.Those items which are also identified
as hazardous are addressed in a companion 8MP manual on fuel and hazardous
materials.Table 2 is intended only as general guidance.The classifica-
tion of wastes liste~in Table 2 is not a substitute for case-by-case waste
stream analysis to assure that hazardous and non-hazardous wastes are
segregated and managed in accordance with federal and state hazardous waste
la\Ats as more fully described in the fuel and hazardous materials 8MP
manual.Basically,the liquid and semi-liquid wastes which are likely to
be found in camp situations can be separated into three categories:
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TABLE 2
CAMP GENERATED CONTAMINANTS
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Wastewater related to domestic uses
Construction waste related to fabrication,erection,and finish-
ing of the project
o Maintenance and operation wastes related to petroleum,oil,and
lubrication products as well as other hazardous materials.
As practicable,the various materials will be separated at the point of
origin.Mixing of waste generally complicates the classification and
treatment process and in certain instances prevents treatment.
:~.2.2 Was tewa ter Sources and Strengths
2.2.2.1 Water Treatment Backwash
~!ost fly camps or short-duration exploratory operations will provide
treatment as dictated by their raw water source.Generation of water
treatment by-products is limited.Larger camps that obtain drinking water
from local sources may produce sludges from filter backwash containing
algae,sediment,debris and chemical flocculants.The quantity of waste
produced is a function of the turbidity and chemical composition of the raw
water.Reverse osmosis can produce wastewater with high salinity.So also
do softeners using ion exchange and sodium chloride as the degenerate.
Flocculants generally are aluminum sulfate,ferrous sulfate,ferric sul-
fate,ferric chloride and coppers.Activated carbon is also used,and
unless recharged,becomes disposable.Lime and soda ash,if used as a
softener,will cause a precipitate to settle out in the contact tank and in
the filter bed.Every water treatment process except chlorinaticn will
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produce a wastewater or sludge which may hinder or enhance a sewage
treatment process.It may be beneficial to operate the water and sewage
treatment systems independently until the steady-state parameters of each
are known before combining sludges.
2.2.2.2 Domestic Waste
The strength of waste and quantity generated are very closely tied to the
size of the operation and the availability of potable water.Fly camps may
use "honey buckets",priveys,incinolets,and pit toilets.Large 3,000-man
facilities with a 5-to 10-year life may have all of the modern conven-
'fences.The strength of workcamp wastewater is characteristically higher
than normal domestic wastewater,although per capita flow rates may be only
slightly less.BODS and suspended solids can typically average 400 to 600
mg/l.While flow rates at Alyeska camps were calculated at about 66
9al/cap/day (250 l/cap/day)in 1979,average water use in camps today
approximates 100 gal/cap/day (378 l/cap/day).Flow rates at the lower
level may cause problems in meeting regulations with secondary treatment
because of the hi gher strength wastewater.·The more mi 11 i grams per 1 iter
of suspended solids and BODS in a wastewater,the higher percent removal
that is required to meet fixed criteria.
There are several explanations for the strength of camp wastewater.These
include:
_0 Limited water supply
o High per capita food consumption and waste generation
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o High grease content in kitchen wastewater
o Entry of cleaning compounds,used in camp maintenance,into the
sewerage system
o Lack of groundwater infiltration into the sewers.
Flow Rates and Constituents
Per-person sewage flows are quite variable among camps and communities in
cold regions.Tables 3 through 5 are representative of the current
available data.In general,institutional facilities such a.s military
stations and construction camps,tend to have strong flow variations
because a large portion of the population responds to the same schedule.
The peak flow will usually occur in late afternoon when personnel are using
the bath and laundry.Two such peaks will occur at those installations
operating on a continuous two-shift,24-hour cycle.The peak daily flow
rate for desi gn purposes shaul d be three times the average daily rate for
institutional facilities.In general,the average rate for camps will be
100 gal/cap/day.For non-resident day workers,an allowance of 15
gal/cap/day per 8-hour shift should be made.
Civil ian communities and similar residential areas have less sharply
defined flow variations.In general,a single major peak,approximately at
mid-day,will occur.The time is dependent on transmission distance from
the homes to the treatment system.The daily peak flow rate of these
communities should be taken as two times the average daily rate.The u.s.
Public Health Service uses a factor of 3.5 people per residence for designs
in small communities.
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TABLE 3
TYPICAL AVERAGE PER PERSON SEWAGE FLOW 1)
Permanent Military Bases and Civilian Communities
a)greater than 1000 population with conventional piped water and
sewage:
Average 300 l/person/d
79 gal/cap/d
b)less than 1000 with conventional piped water and sewage:
Average 240 l/person/d
63 gal/cap/d
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c)with truck haul systems,conventional internal plumbing:
Average 140 l/person/d
37 gal/cap/d
d)with truck haul systems,low flush toilets:
Average 90 l/person/d
24 gal/cap/d
e)no household plumbing,water tanks and honeybucket toilet:
Average 1.51/person/d
0.4 gal/cap/d
f)same as (e)above BUT with central bathhouse and laundry:
Construction Camps
Average
Average
15 l/per50n/d
4 gal/cap/d
220 l/person/d
58 gal/cap/d
Remote Military with Limited Availability of Water
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Average
1)Source:Smith,et al (1979).
130 l/person/d
34 gal/cap/d
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TABLE 5
TYPICAL WASTEWATER DESIGN PARAMETERS IN CANADA AND USA 1)
gall 1 itersl lb BOO/mg BOOI lb S51 mg S5/
Community cap/day cap/day cap/day cap/day cap/day cap/day
Construction Camp 50 189 0.15 68,100
Average Subdivision 80 303 0.17 77,180
Hospitals 200 757 0.30 136,200
Major Cities 135 511 0.20 90,800 0.23 104,420
2)Values Most
Frequently Quoted 100 378 0.17 77,180 0.20 90,800
1)Source:Grainge et al (1973)
2)These values yield a BODS concentration in raw sewage near
200 mg/l,and a suspended solids concentration of 230 mg/l.
Minimum flow rates are important to the design of grit chambers,monitoring
devices,dosing equipment,etc.A minimum rate equal to 40 percent of the
average rate should be used for design purposes.
Table 6 summarizes the sanitary facilities provided at several
institutional installations.It should be noted that OSHA regulations will
determine the minimum number of fixtures for a system.
TABLE 6
INSTITUTIONAL SANITARY FACILITIES IN COLO CLIMATES 1)
(units per person)
Toilets Urinals Sinks Showers
Thule AFB,Greenland 1/10 1/27
P Mountain Radar,
Thule Greenland 1/15 1/45 1/8 1/14
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50-Man Winter
Camp Tuto,Greenland 1/10 1/25 1/6 1/10
Wainwright,AK 2)1/47 a 1/94 1/47
-1)Source:Smith et al (1979)
2)The gray water/black water concept is used at the
Wainwright,AK,central facility and should be considered
wherever water conservation is an issue.Black water is
considered to be that related to human wastes from toilets,
urinals,etc.Gray water (the remaining wastewater from
showers,sinks,laundries)is recycled for the toilets.
The percentages of da i1 y flow from community sewage sources,as presented
in Table 7,have been averaged from numerous studies.Table 8 presents
s'imilar data for military field bases.The percentage of daily flow at
ar'my field bases for washracks (12 percent)is similar to flows at camps
for equipment washing.
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TABLE 7
DOMESTIC SEWAGE SOURCES
(%of average daily flow)
Category
Toilet,Urinal
Shower,Sinks
Kitchen
Laundry
%
37
32
12
19
100
TABLE 8
ARMY FIELD BASES (lOCO-6000 yOp)
(%of average daily flow
Category
Photographic
Aircraft Washrack
Vehicle Washrack
Hospital
Toilets,Showers,Sinks
Kitchen
Laundry
%
5
9
3
1
60
6
16
100
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The concentrations of wastewater constituents will vary "lith the amount of
water used and the type of facilities employed.However,the actual mass
loading of organics and related substances should be relatively constant on
a per person basis.Table 9 gives estimated mass values for the major
domestic wastewater sources.The values are based on a comparative analy-
sis of a number of data sources.The fi na 1 item,n ins t itut i ona 1 garbage
grinders",reflects the common practice at military stations and many
construction camps of grinding most of the kitchen wastes for inclusion in
the wastewater stream.The treatment system must be designed specifically
for garbage if it is to be accepted.Disposal of cooking oils,animal
fa.ts,crisco,butter,etc.down sink drains can plug up sewers.Skimming
devices may be required to reduce constant back-up and maintenance.
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TABLE 9
ESTIMATED SOURCES OF SEWAGE POLLUTANTS
(per person per day)
Sourcl~BODS SS Total Total
Nitrogen Phosphorus
Grams Pounds Grams Pounds Grams Pounds Grams Pounds
Toilet 60.8 0.13 85.2 0.19 14.7 .0323 1.67 0.0037
~.Bath/Shower 5.33 0.01 5.12 0.01 0.31 .0007 0.04 0.0001
Laundry 7.92 0.02 7.70 0.02 0.23 .0005 0.67 0.0015
Kitchen 16.8 0.04 10.0 0.02 0.49 .0011 0.49 0.0011
Subtotal 90.8 0.20 109 0.24 15.7 .0346 2.83 0.0064
Institutional
Garbage
Gri nders 59.0 0.13 58.8 0.13 1.31 .0029 0.95 0.0021
Total 150 0.33 165 0.37 17.0 .0375 3.78 0.0085
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All the values in Table 9 are independent of the amount of water used for a
particular activity and below the strengths of many camps.Combining these
values with data in Tables 2 and 6 or other sources will allow
determination of concentrations for a particular case.The following two
examples,based on 58 and 24 gal/cap/day (220 and 90 l/cap/day),
demonstrate systems that will require tertiary treatment.A flow rate of
100 gal/cap/day (378 l/cap/day)would be more realistic of current
conditions.
!:xample 1:
200-man construction camp,all conventional facilities,central dining and
kitchen with garbage grinder.
From Table 3:Assume flow =58 gal/person/day (220 l/person/day)
From Table 9:grams/person/day
BODS 55 N P
Totals include toilets,
1,p4P.
baths,laundry,kitchen,
}~garbage grinders 150 165 17 3.8
x 200 people =30,000 33,000 3,400 755
Total Flow:220 x 200 =44,000 l/day.
Concentrations:BODS
55
30,000 f 44 =680 mg/l
33,000 ~44 =750 mg/l
N 3,400 +44 =77 mg/l
P 755 +44 =17 mg/l
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Example 2:
Small community,truck haul,internal plumbing,low-volume flush toilets
(assume 100 people).
Table 3:flow =24 gal/person/day (90 l/person/day)
Table 9:grams/person/day
BOOS
91
55
109
Total N
16
Total P
3
Design concentrations:
1-mg/l =grams/person/day +l/person/day x 100 mg/g
BOOS 1011 mg/l
,....55 1211 mg/l
N 177 mg/l
p 33 mg/l
Temperature
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The temperature of the raw wastewater entering the sewage treatment plant
C,:in strongly influence efficiency of most unit operations and processes.
Temperature control is also necessary to prevent unwanted freezing either
in the system or at the point of final discharge.
The energy level presented by moderate (SO°F)to high incoming sewage
temperatures should be considered as a resource.The treatment system and
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its protective elements should be designed to take full advantage of this
available energy.For example,the municipal treatment plant in Fairbanks
extracts energy from the effluent via a heat pump and this is used to heat
the enti re facil ity.
The seasonal temperature of the body of water which ultimately receives the
,~astewater is an important factor depending upon its relative size and the
existing use of the water for fisheries,recreation,water supply,etc ..
The temperature of raw wastewater is a function of the raw water
temperature,the use of electric heat trace and insulation on sewers,the
water and sewage system design and characteristics (utiliducts,utilidors,
trtl,nsport distance),the use,number and plumbing (hot water)of buildings
serviced,and the ambient temperatures.Some values of raw wastewater .
temperature are presented in Table 10.
2.2.2.3 Construction Wastewater
Drilling operations often make use of a drilling mud (bentonite and water)
s"lurry to assist in reducing the heat of the bit,seal sides of the hole,
and carry tailings to the top.Generally it ;s injected,recirculated at a
site,then abandoned in an approved disposal site.Exploratory drilling
for projects recovers cores;any wastewater for hard rock drilling is
discharged for overland percolation or,if required,to settling ponds
prior to discharge.
-20-
-
1)Source:Smith et al (1979)
Wastewater generated during camp construction usually consists of pressure
testing water (if used in lieu of air)and the chlorinated water resulting
from disinfection of the potable water system.
J~nother source of potential wastewater is surface runoff and associated
sediments from construction activities.Proper design or location of
control devices such as settling ponds is required to maintain state water
qual ity standards for the receiving waters.These control devices are
addressed in a companion BMP manual on erosion and sedimentation control.
Similarly,the batching of concrete can produce waste slurries that require
treatment and/or disposal.Batch pl ant operators and truckers haul ing
concrete wil1 usually require an area for disposal of their wastes and
"was h down"waters.These wastes require special treatment and an approved
disposal area away from wetlands and waterways.
2.2.2.4 Maintenance and Operation
An operational camp requires support facil ities similar to those of the
construction camp.Maintenance activities require garages,washing and
steaming of equipment prior to repair,use of solvents,antifreeze,petro-
leum products,lubricants,incineration,etc.which may produce hazardous
wastes.Care must be taken to segregate these materials from non-hazardous
,Wfterials and prevent their entry into the domestic wastewater stream.
Ii
-22-
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2.3 CONCEPTUAL CAMP LAYOUT,COLLECTION AND TREATMENT SYSTEMS
At this stage of the design process,preferences will be develop~d for
certain types of collection and treatment based on project data and field
lreconnaissance.Liaison with state,federal,and local government
personnel whose jurisdiction covers wastewater treatment,plan review
and/or treatment requirements should be ongoing.
~~.3.1 Water Supply Requirements
The quality and quantity of potable water should be verified by researching
project records on stream data,exploratory drilling,any well water draw-
down data,changes due to various seasons and weather conditions,etc.
Evaluation of the raw water source should consider that its chemical and
physical characteristics may add backwash water (more to treat)and/or
treatment residues (change of wastewater characteristics).
Alternative water sources should be considered should water availability
b4~come a limiting factor in wastewater treatment feasibility.In many
instances,a dependable water source such as a well system or impoundment
may be required to size a treatment facility which will effectively treat
the wastewater within the parameters of state or federal permits.
2.3.2 Wastewater Collection and Treatment
All siting of waste collection and treatment is a function of the location
of the water supply,minimization of length of collection and delivery
-23-
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lines,location of ultimate receiving body,soils,ground water,surface
water,and terrain of the area.
Gently sloping high ground with free draining soils would be the optimum
site even if the location is less convenient than others to the work or
water supply.Core boring will be needed on large sites to verify subsoil
conditions and insure foundation stability as well as to identify the
presence of permafrost or bedrock which could interfere with installation
of sewers and other utilities.
Waste collection and treatment facilities should not be located in flood-
plains.wetlands,in the path of natural drainageways,or near waterbodies.
Nor should they be located where they could cause odor problems at camp,or
attract wildlife.
A minimum of three alternative systems should be considered for each
project site.These alternatives are a function of the following:
o
o
o
o
Size -phases of camp size and development
Duration -length of camp usefulness
Location -variables of camp location
Cost -relative construction operation and maintenance of
collection and treatment facilities
Two systems are usually fairly easy to develop but the third may require a
more detailed investigation which often results in a better idea or
modification.Modular units that can be plugged in and out or multiplied
to obtain the ultimate treatment are desirable.Transportation and
-24-
.....
installation t which could take place in the most remote of locations and in
the most severe weather t are important considerations.Other aspects to
cons'ider are the flexibility or durability of the system if the loading
rate 'is different or the time it is in service changes t and the degree of
sophistication required for the training of wastewater treatment facilities
operators.Costs also need to be developed at this time in enough detail
to comparatively rank the possibilities.
2.4 DESIGN OF COLLECTION SYSTEMS
This section discusses the characteristics of collection systems by camp
and system characteristics.Tabl e 11 summarizes the characteri sti cs of
typical collection systems in remote camp areas.
2.4.1 Characteristics by Type of Camp
2.4.1.1 Exploratory and Fly Camps
W'ith a collection system relying on the individual users to bring their
wastes to a disposal point,the important considerations are the types of
containers in which the waste is transported and the facilities at the
point of discharge.
Containers used by individual s for transporting wastes will vary from
conventional oil drums to porta-can pails.The containers should be sized
for the way they will be transported and should be covered.
-25-
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TABLE 11
CHARACTERISTICS OF WASTEWATER COLLECTION SYSTEMS!)
Cravity
Vacuum
Pressure
SOIL CONDITIONS
Non-frost susceptible
or slightly frost
susceptible .nth
gravel backfilling
material.
Most useful for frost
susceptible or bedrock
conditions,but can be
used with any soil
conditions.
Most useful for frost
susceptible or bedrock
conditions,but can be
used with any soil
conditions.
TOPOGRAPHY
Gently sloping
to prevent deep
cuts and 1i ft
statton.
Level or gently
sloping.
Level,gently
sloping or
hilly.
ECONDMICS
J'iftial construction
costs high but opera-
tional costs low
unless must go above
ground or use lift
stations.
Initial construction
cost moderately high.
Operational costs
moderate.
Initial construction
costs moderate.
Operational costs
moderately high.
OTHER
Low Maintenance.High health
and conventence improvements.
Must hold grades.flushing
of low use lines may be
necessary.Large diameter
pipes necessary.
"Traps"every 300 feet.
Low water use.
High health and convenience
improvements.
Must have central holding
tank for each 30 to 50 ser-
vices with additional pumps
to pump waste to treatment
facHities.
Can separate gray and black
water.
Use small pipes.
No exfiltration.
Low water use if low water
use fixtures ar~installed.
High health and Convenience
improvements.
No central facility necessary
-units are in individual
buildings.Number of
services are not limited.No
infiltration.Use small
pipes.
-I
Vehicle-Haul Year-round roads
must be available.
Level,gently
sloping or hilly.
Initial construction
cost low.Operational
costs very high.
Low water use and moderate
health and convenience
improvements.
Operational costs must be
subsidh:ed.
Individual",
Haul
Used with any soil
conditions but
boardft'a 1ks are
necessary in extremely
swampy conditions.
Level,gently
sloping or hilly.
Initial construction
cost and operational
costs very low.
Low usage by inhabitants and
thus low health and
convenience improvements.
,)
Source:Smith et al (1979)
.....
2.4.1.2 Small and Intermediate Camps
Camp-haul sewage collection involves the co·llection of wastewater from each
point of generation and its transportation by a contractor-operated track
or wheel vehicle to a treatment and/or disposal facility.Facilities at
camp dwellings generally consist of holding tanks located on or beneath the
floors of buildings into which wastes from sinks,lavatories,toilets,and
kitchens drain by gravity.The tanks are then emptied into a collection
vehicle by pumping.With any haul system,low water use plumbing fixtures
are necessary to reduce water consumption and to minimize wastewater
generation.
The efficiency and operational costs of this type of collection system are
dependent partly on the sizing of the holding tanks.For most circum-
stances,tanks should be around 260 gallons,but at least 100 gallons
larger than the water storage tank provided.The size of the collection,
reliability of the service,and climatic conditions should be considered in
sizing wastewater storage tanks.It is also important to provide for the
structural support in any building required to carry this additional load.
The tank must be constructed with a large manhole with removable cover so
it can be cleaned and flushed out at least yearly.Fill alarms and volume
metering ports should be provided.It must be well insulated,kept within
the heated portion of the building and/or heat must be added using heating
coils or circulating hot water to prevent any ice formation.While holding
tanks have sometimes been buried in the ground beside or beneath
-27-
~,
-
facilities,this should not be done in permafrost areas.The tanks must be
placed so they are emptied from the outside of buildings.
The hose connection should be of the quick-disconnect type and be a
different size and color than t~at of the water delivery hose,to eliminate
the possibil ity of a cross-connection.The pumpout connection at the
building must be sloped to drain back into the tank after pumping so sewage
does not drain outside or stand in the wind and freeze.The tanks must be
properly vented to provide adequate air exchange during filling and
emptying.
Two methods of emptying the holding tanks are in use in the north.With
one,a prp.ssure tank is used on the vehicle.The tank is held under a
vacuum using a small compressor and a three-way valve.The contp.nts of the
hol ding tank are withdrawn into the truck tank under vacuum.At the
disposal point the valve is turned to pressurize the tank,forcing the
wastewater out.The other method is similar except that sewage pumps are
used instead of a compressor and the vehicle tank does not have to be
pressure rated.
2.4.1.3 Intermediate and large Camps
large facil ities are designed for the convenience and sanitation which
accompany piped sewage collection.Whenever the d~ration of the camp site
will exceed 5 years,a piped system deserves consideration.There are
sp.veral variations of piped sewage collection systems.Normally,a conven-
tional gravity system has the lowest life-cycle cost and should bp.used
-28-
F'!'
.!
,-,
\
whenever feasible.However,the layout of the site and/or the soil
conditions may make a vacuum or pressure sewage collection system neces-
sary.An additional advantage of a gravity system is that a freezeup
seldom causes pipes to break.The freeze lip is gradual and in layers,in
contrast to pressure lines which are full when freezing takes place.
~!hen soil conditions do not allow burying collection lines,they must be
placed on or above the surface of the ground.In most locations,the
topography and building layout would dictate above-ground lines on pilings
(or gravel berms)to hold the grades necessary for gravity sewage flow.
Above-ground lines are undesirable because of transportation hinderance,
high heat losses,blocked drainage,vandalism,and the cluttered look they
create.It may be preferable to use a pressure or vacuum collection system
so that the lines can be placed on the ground surface to minimize the above
problems.
Sewage collection lines may be placed in utilidors with other utilities,
depending on the local circumstances.Assuming the same design,heat
losses (and thus operation and maintenance costs)of above-ground
facilities are nearly three times as high as for the same line placed
below-ground because of the greater temperature differential between the
inside and outside of the line.
Sewage temperatures are also an important design consideration.In camps
or villages where the individual buildings have hot water heaters,sewage
temperatures usually range between 50°and 59°F.Where hot water heaters
are not used and any hot water must be obtained by heating water O~a cook
-29-
.....
!
F"I"
I
I
~
I
.....
i
...,
I
"""'1
I
stove,sewage temperatures range from 39°to 52°F.Heated utilidors,
utiliducts,and sewer lines can deliver sewage at temperatures upwards of
60°to 65°F.~greater percentage of this heat will be 10st between the
users and the point of treatment with a gravity system (\'lithout heat
tracing)than with a utilidor,pressure or vacuum system because the sewage
is longer in transit and there is air circulation above the sewage in the
pipes.It is often necessary to use electric heat trace at the ends of
little-used laterals or throughout the collection piping in a gravity
system to eliminate freezing problems caused by the lines slowly icing up.
~lso,a greater percentage of the heat will be lost if the lines are above
ground.Sewage heat losses will vary considerab1y from summer to winter
with buried lines,depending upon the presence of permafrost.The presence
of permafrost,however,requires an entirely different approach to the
design and placement of underground utilities.
2.4.2 Collection Systems
The following paragraphs discuss design considerations for three types of
systems used in remote,northern climates.Common to each system are the
following considerations:
o Storm water or melt water runoff should not be included in
sewers.The waters could lower wastewater temperature,overload
treatment facilities hydraulical1y,and deposit sand and grit
in collection lines.
-30-
o Insulated pipe should always be used in cold regions unless lines
can be buried well below the active layer and not in permafrost.
1
I
o Flex couplings must be provided in facilities designed for use in
areas subjected to frost heaving or subsidence.
o In providing wastewater and water 1 ines through the use of a
common uti1idor,care must be taken to ensure that no cross
connections can occur or that the potable water line is protected
from any sewage in the util idor as in the case of a sewer 1 ine
break .
..,.
i
i
o
o
It is better to design the sewer system so there is at least one
large user near the end of each lateral to eliminate the need for
flushing.
All fixtures should be placed on inside walls which are warm on
both sides.If possible,the sink should be placed on the
opposite side of the bathroom plumbing wall to reduce the length
of drain lines.
o All fixtures and lines should be installed so that they can be
drained or otherwise protected from freezing.Drainable P-traps
shaul d be used and the user shoul d be aware that antifreeze
solution should be added to the toilet and sewer line low spots
if there is a danger of freezing during non-use.
-31-
1
-r
!
o Vents shoul d be constructed of low conductivity material and
should increase in size as they go into the unheated atmosphere.
One and one-half inch vents should be increased to 3 inches and
3-inch vents should be increased to 4 inches.
2.4.2.1 Conventional Gravity Collection lines
If lines can be buried and the layout of the site is sloping,a gravity
sewage collection system will have lower operation and maintenance costs
than other types of systems.
The most important design consideration with gravity sewers is the minimum
grades necessary to ensure adequate velocities in the pipelines.Building
service lines should have a nominal pipe size of 4 to 6 inches and a
minimum slope of 1 percent.The following minimums for main collection
lines should be used with stable ground conditions (frost-susceptible and
permafrost areas have additional design controls):
"""I
I
I
.....
Nominal
Pipe Size
(inches)
6
8
10
12
14
15
~li nimum 51 ope
(percent)
0.6
0.5
0.4
0.3
0.22
0.17
.....
If soil stability is uncertain (i.e.,a small amount of settling or heaving
is likely),a minimum slope of 1 percent should be used for all collection
lines.They should be backfilled with non-frost susceptible sand or gravel
-32-
I~
-
at least 12 inches at the bottom and sides of the pipe (Figure 1).The
4-inch service lines should be placed the same way with a 2-percent minimum
slope.Higher slopes than those above should be used if possible because
the longer the sewage is in the collection system,the more heat it will
lose.In small camps,minimum sewage collection line sizes could be 6
inches instead of the normal 8 inches.
Lines usually should be buried at least 2 feet to prevent damage from
surface loading.Less depth could be allowed in areas with no roads or
vehicular traffic.
In addition to the steeper slopes listed above,provisions should be made
to adjust the slope of a line if it traverses an area where movement is
likely.With lines on piling,blocks are placed between the piling and the
pipel ine and act as shims.They can be removed or added to adjust the
slope.A utilidor can be suspended with adjustable turnbuckles or placed
on adjustable yokes or supports.
Gravity sewer lines should be checked regularly and when the depth of flow
indicates sedimentation or blockage.All cleanouts should be inside of a
1itt stati on.
Figures 2 and 3 show typical service line connections to a bUilding for a
cold region gravity sewage collection system.They should slope at least
1 to 2 percent to the collection main,depending on soil stability.Of the
two examples shown,the method of going through the wall is preferable to
going through the floor.The former will allow for more movement of the
-33-
-
"'.
Compacted Backfill ".
Variable
'."
....;
".
.":.".,
t ..,.........
".
4"
•.,. -'&:..~~l..£-~":"':::..;;I"•.....ll..
":.,"":.0 ...:.."
,..".':..
Pipe ---,;"..--~~
Hand Tamped Backfill --....;,-"'*~:
Bedding Gravel or Sand __~~..~
to Top of Pipe
F""
I ALASKA POWER AUTHORITY
TYPICAL SEWER AND
WATER BEDDING DETAILS
FIGURE 1
Building floor
B",.,~1;])
Box.-/'
--rr---"'''''''---.."To building sewer-
'--:',....-90 f!J x 500 lexible hose
7S pvcl:%J
_--'-:--100 x 75'A:ducing bell coupling
Filled with polystyrene
or fiberglass insulation
Flexible rubber drain housing
Band
Approximate ground line
Filled wllh polystyrene Plug
or rlberglass Insulation ~
I
All temperature grease~::1
I i gO
I I
• I
I I_=__>(iS~•..ql.-jp.ill.....~_""~
Corrugated metal pipe filled-I.;.:'
Of"smooth to reduce froat jack Ing..::
Wood box with removable
lid screwed on wilh
wood screws
DETAIL
--
ALASKA POWER AUTHORITY
SEWER WALL CONNECTION
FIGURE 2
DETAIL
. •::.0..-:.::tQ.'.-O.
·-0--..·0·.··f':".-:..•••0··
Corrugated Metal Pipe •••
(Filted-in or Smooth to
Aedue.Frost Jacking)
To Sewer Main
....~....---Plug
"'-....--AII-Temperature Grease
1-oliII....-..;..--900'Flexible Rubber Hose
~=---75PVC
--:;::'-_-.oj100 x 75 Reducing Bell Coupling
ft.-4-Band
!.Q.::..:=.;::.:'.~::.
..:.g_••_.-•••(I••:0 ::.:-::..-·0 .....
••••D
~-~~~:o....;.:""!"'.-:100 PVC
ALASKA POWER AUTHORITY
SEWER FLOOR CONNECTION
FIGURE 3
-
building without damage to the sewer service line.It also pemits all
plumbing to be kept above the building floor.
2.4.2.2 Pressure Sewage Collection Systems
If soil conditions and camp layout make a gravity collection system
impractical,a pressure system may be considered.A small pump-grinder
unit in or near each building provides the force for the pressure system.
While construction costs would probably be lower than either a gravity or
vacuum system,operation and maintenance costs would be greater than for a
gravity or vacuum system because of the pump-grinder units in each
building.
The largest advantage of this system is that it is not necessary to
maintain grades.Pipelines or utilidors do not have to be on piling or up
off the ground.They can be at the surface or buried.Small movements due
to frost heave or thawing will not affect operation nor will there be
problems with infiltration of groundwater because the lines are under
pressure.A disadvantage is that pressure lines lay ftlll which allows
sedimentation and freezing.
The collection lines must be sized to maintain a minimum of 1 foot per
second scour velocity.The minimum size collection line is I!inch,which
would be the size for one unit.If more units are added than were
originally planned for,velocities will increase down the line.The effect
of this velocity increase is an increase in head loss.Pressures should be
held below 40 psi in the layout.The lines should be slightly undersized
-37-
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.-
(higher velocity)rather than oversized if the correct size (for 1 foot per
second)is not available.In the design of a pressure system,an assump-
tion that 33 percent of the pumps will be operating at once is recommended
for sizing pipes.
The collection lines should be designed to be safely drained if the system
has to be shut down during the winter for maintenance.Grades should not
undulate with the terrain as this would establish a need for air and vacuum
relief valves as well as dips which will freeze.The pressure collection
lines should be heated,if required,by heat tape,hot air in utiliducts,
circulating glycol,steam,etc.Air relief valves should be installed at
all high points in the line to allow filling and pressure testing at start-
up as well as for operation.
The pump-grinder units can be situated in each bUilding or several
buildings could drain into one unit by gravity.The units should be
designed to pump against the design head in the main plus a 40 percent
overload (with 33 percent of the pumps operating at once).Each unit
should have complete duplication of controls,sump pumps,and pumps or
compressor,for standby.The extra unit would take over if the primary
unit is inoperable and,at the same time,set off a warning device (audible
and visual)to alert the operator that repairs are required.Standby power
should be available in case of a power outage for units serving several
bUildings.The pumping units should be well insulated and installed on a
stable foundation if they are placed outside or in the ground.As with
lift stations,they must be protected from frost jacking forces.
Double-check valves should be provided on inlets and outlets to prevent
-38-
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~.,
pwM'
!
backflow.Weighted check valves have proven more satisfactory than spring-
loaded valves.
The pump-grinder units designed to serve individual buildings are equipped
with positive displacement pumps which have a nearly constant pumping rate
over a wide range of heads.The grinder unit reduces all foreign objects
to 0.26 inches before they go into the pump.The unit must be able to
handl e unusual items fl ushed down the toi lets such as rock,wash rags,
utensils,etc.Positive displacement pumps require a lower power input to
purge the system of any air pockets.The units must be small and light
enough that they can be easily removed from the sump and repaired while the
standby unit continues to operate.
The sump or tank from which the pump draws must be designed so that it is
cleaned by scouring as the pump operates.The outlet check valves should
be located in a horizontal run to prevent solids from settling in them when
the pump is not running.Pressure sensors should be used to control pumps
and alarms (rags and grease tend to foul float sWitches).The sump should
be sized to provide several days'storage in case of a temporary power
outage or other problem.It should be constructed of fiberglass or plastic
for protection from corrosion.
The pressure system can also be modified by using conventional submersible
sewage pumps in holding tanks at each building.The tanks are similar to
septic tanks where the solids settle~biodegrade anaerobically~and are
pumped out by truck occasionally.The submersible pump pumps the relative-
ly cl ear effluent into the pressure sewer 1ines to a treatment facil ity.
-39-
..1""""
Some of the advantages of this type of operation are:
o Problems with the grinder on the pump plugging up are eliminated.
o There are no solids to settle in the collection lines.
o The treatment facility is not as complicated as for conventional
sewage.
Pressure sewer lines should be tested as any pressure water line would be.
If using water or liquid,use It times the working pressures with an
allowable loss of 3 gallons in 24 hours.If using air,use H times the
working pressure with an allowable loss of 103 psi in 24 hours.Great care
must be exercised when using compressed air because of the possibility of
explosion.Air testing must be used at below freezing temperatures.
2.4.2.3 Vacuum Sewage Collection Systems
As with pressure systems,a vacuum sewage collection system should be
designed only if soil conditions and camp layout negate a gravity
collection system.Vacuum systems are not limited to holding grades,but
are limited to 15 to 20 feet in elevation differences because they are
operated at 8 to 10 psi vacuum.Vacuum systems are limited to 30 to 50
services on a given collection line.
Toilet wastes,with a small amount of water,are transported in the pipes
by the differential pressure between the atmosphere (air admitted to the
system with the flushing action)and a partial vacuum in the pipe created
by a central vacuum pump.The flow conditions are slug-type,but the
-40-
(traps)is a disadvantage of the vacuum system.
1 To reform the slug flow,friction in the pipe breaks down the water s ug.
transport pockets are required at intervals of about 200 to 300 feet.The
vacuum toilets only require 0.3 gallons of water to flush and the collec-
tion lines are small (2 inches).The requirement for transport pockets
Because the traps wi 11
for extended peri ods of time,they ITlUS t behaveliquidstandinginthem
11 · 1 t d They should also be pro-inside a heated util idor or be we ,nSll a e·.
vided with drains.
The collection line sizes will depend on the number of fixtures on a line
and the estimated number that will be operating simultaneously.Usually 2-
are used w,·th the traps dipping at least one and one-halfto2!-inch lines
pipe diameters.Tests have shown that head losses increase about linch of
mercury for each 984 feet of collection line velocities of 15 feet per
second or 1ess.Because the 1i nes carry a combi nati on of a ir and water,
head losses are nearly impossible to compute.However,when going uphill,
the increase in head loss is only about 20 percent of the actual elevation
increase.Most fixtures will not flush if there is less than 6 to 7 psi
vacuum in the collection lines.Thus,if several are flushing
simultaneously and the vacuum.drops to 6 to 7 psi,additional fixtures will
not flush until the vacuum builds back up.Gray water (sink,shower and
tub wastes)can be separated from black wat,=r (toilet wastes)for treatment
purposes or water reuse,by haVing the toilets on a different collection
H.ne than the gray water fixtures.In low use lines where it is not
desirable to have sewage stand in the traps for extended periods,an
automatic or timed valve can be installed to bleed air into the end of the
line and keep the wastewater moving.Full opening ball valves should be
-41-
installed approximately every 200 feet so that sections of the lines can be
isolated to check for leaks or plugs.
A collection tank is located at the end of the collection lines.The tank
is held under a vacuum at all times by liquid-ring vacuum pumps which must
be sized to evacuate the air and liquid admitted to the system by the users
with a safety factor of two.(In Noorvik,Alaska,the design figures used
were six flushes per person per day for the toilets and 30 gallons per
person per day for sinks and showers.For 50 houses,pumps were selected
which were capable of evacuating 64 cubic feet per minute at a vacuum of 16
inches of mercury.)The collected wastes are pumped out of the tank to the
treatment facil ity using conventional centrifugal pumps.They must be
designed to pump with a negative suction head equal to the maximum vacuum
under which the tank must operate.The collection tank is sized similar to
the pressure tank in a hydro-pneumatic system.One-ha 1f of the tank
capacity is used for liquid storage and the other half is space (vacuum)
serving as a buffer for the vacuum pumps.Several alarms should be in-
cluded in the tank to give warning of high levels of sewage in the holding
tanks,low incoming sewage temperature,and low vacuum in the system.
2.4.2.4 Lift Stations
Sewage 1 ift stations are used mainly with gravity collection systems but
coul d be used with pressure sewage coll ection systems,and even vacuum
systems (to pump the waste from the collection tank to the treatment
facility).The advantages and disadvantages of several types of lift
stations are shown on Table 12.
-42-
TABLE 12
TYPES OF LIFT STATIONS
TYPE ADVANTAGES DISADVANTAGES
l.Submersible Low initial cost;low Difficult to make field
maintenance requirements;repair of pump~requires
does not require installa-specialized lifting
tion of appurtenances such equipment to remove pump.
as heaters~dehumidifers,
sump pump~etc.;station
f"lll""-can easily be expanded and
increased in capacity;
available for wide range of
capacities.Littl e of the
structure is above ground
so heat losses are greatly
I>->/.reduced.
i
High initial costs;I 2.Dry Well Pumping equipment located-
away from wet well;low requires larger
cost per gallon capacity;construction site.
good reliability;high
efficiency;desirable for
large installations;
easily maintained.
3.Wet Well Low initial cost;high Requires explosion proof.l"""efficiency;wide range electrical motors andi.
I of capacity available.connections;difficult:,!
to maintain pump.
4.Suction Lift Good reliability;avail-Suction lift limited toableforwiderangeof15feet;decrease in
,-.".capacity.priming efficiency as
pump ages.
5.Pneumatic For low capacity (40 gpm)Somewhat more complex-Ejector low head,short distances;than other types of
generally nonclogging;stations;high mainten-
100 gpm maximum usually.ances;low efficiency.
f"'"
-I
The outside of the station should be insulated with at least 3 inches of
urethane or styrofoam with an outer protective covering to protect the
insulation from moisture.Insulation should be placed underneath the
station to prevent settling due to the thaw of frozen ground.Visqueen
(plastic)or some other bond breaker should always be used to reduce frost
jacking in the active layer.If thawing and settling under the station is
anticipated,pile foundations extending well into the permafrost are
recommended.All stations must be attached to concrete slabs to provide
sufficient weight to overcome the buoyancy of the station itself if it were
completely submerged in water.Pressure coupling (flexible)type connec-
tions are recommended at the inlet and outlet of the stations to prevent
differential movement from breaking the lines.
Alarms are necessary in any lift station.All critical components,such as
pumps and compressors,should be duplicated in each station.The controls
should allow the operator to specify operation of the pump or compressor,
with the identical standby unit taking over if one or the other does not
start.An alarm (both visual from the surface and audible)would then warn
the operator that one unit is malfunctioning.The alarms can also be set
for the temperature and water level in the station.These alarms should be
tied back into a central alarm panel in the pumphouse or to the treatment
plant.Standby electrical power should be provided for each major lift
station.
Inlet screens must be provided to remove items that would clog pumps or
check valves.Each lift station should be checked by the operator and the
inlet screen cleaned daily.Submersible types or .those without a heated
-44-
!If'"''i.,
dry well in whi ch to work shoul d be housed in a heated surface structure
with the electrical controls and alarms.
2.4.2.5 Force Mains
Force rna ins are pressure 1i nes into which the pumps in the 1ift stati on
discharge.They should be designed to have scour velocities during pumping
(2t to 3 feet per second)and to drain between pumping cycles.The line
shoul d be pl aced ina heated util idor or heat traced in some way shoul d
climatic conditions dictate.Another option would be to time the pumping
cycle so the sewage stays in the line for a calculated period,and to size
the holding tank at the lift station to hold at least the volume of the
force main.The mains should be pressure tested and meet all the criteria
of pressure water transmission pipelines.
2.5 DESIGN OF TREATMENT SYSTEM
The selection of the best wastewater treatment and disposal alternatives
depends upon many factors,as shown on Table 13.Some of the most impor-
tant factors include:
o Wastewater characteristics and flows
o Degree of treatment reqUired
o
o
ReCrVing water
ope'~:~ators
'I,.I,.,
-45-
TABLE 13
COMPARISON OF WASTEWATER TREATMENT SYSTEMS FOR CAMPS
TREATMOO SYSTEM
&APPliCATION AOVANTACES DISADVANTAGES
Septic tank with tile field and/or
leach pit -
Non-permafrost areas and small camps
where suitable soil conditions exist
for infiltration of septic effluent.
Septic tank might also be used ahead
of secondary treatment plant.
1.No direct discharge to surface 1.
water.
2.No operating requiretllents except 2.
for septic tank pump out and
sludge disposal at completion of
project.3.
3.low operating cost.
Use limited to non-permafrost areas.
Also,potential freeZing problem during
cold weather.
Potential groundwater contamination
problems.
Probably not suitable for large camps.
Suggested maximum size of 5,000 gal/day.
Short retention lagoon -
Areas where primary effluent may be
discharged with no risk to public
and with negligible environmental
impact.
Z.
3.
"'.
Very simple and dependable.1.
Operator requirement minimal if Z.
properly designed and constructed.
Separate slUdge handling,treat-3.
ment and disposal systems not
required.
4.
Low capital operating costs.
Potential severe odor problems.
Potential groundwater contamination
problems.
Stricter requirements for effluent
discharge.
Require regular effluent sampling and
analysis where effluent is discharged
directly to a receiving water body (less
frequent sampling might be permitted
where effluent is disoharged indirectly.
Operator requirement minimal if
properly designed and constructed.4.
Very simple,dependable,and 1.
flexible if sized adequately.
Oischarge can be timed to protect
the receiving stream during
critical periods.Z.
Long retention lagoon -
Area where large relatively flat
land space is available,winter
retention is desirable and impervious
soils exist.
1.
Z.
3.
Instant start-up.3.
May require Z-year or longer holding
period to achieve secondary level of
treatment.
Potential odor problems.
Potential groundwater contamination
problems.
Large land requirement.
4.Separate sludge handling,treat-
ment and disposal systems not
required.
5.Require suitable geotechnical
conditions,preferably non-permafrost
and impervious soils and low water
table.
5.Low capital cost if geotechnical
conditions favorable.Low oper-
ting cost,low energy cost.
6.Land rec1amati on may be delayed unt it
after project completion.
Aerated lagoon -
Probably more applicable to long-
term construction camps but could
be used instead of long retention
1agoon where 1and area is limi ti ng
or where continuous discharge is
acceptable.
6.Eliminate need for regular
effluent sampling and an~lysis
except when discharging.
1.Simple to operate.1.
Z.Only routine maintenance required.
Z.
3.Separate sludge handling,treat-
ment and disposal systems not
reqUired.
3.
4.Less land area requirement than
for long retention lagoon.
Potential problem with clogging of fine-
bubble air diffusers maintained.
Require regular sampling and analysis if
effluent is discharged directly to
receiving water.
Higher capital and operating costs than
for most long retention lagoons.
TABLE 13 (CONTINUED)
COMPARISON OF WASTEWATER TREATMENT SYSTEMS FOR CAMPS
TREATMENT SYSTEM
&APPLlCAT10N ADVANTACES oISADVANTACES
Extended aeration -
Non-permafrost and permafrost
regions where continuous surface
water discharge is permitted and
where adequate power generation
capacity is available.
1.Proven technology.1.
2.Can produce a highly nitrified
effluent.
3.Excellent results if well 2.
designed (e.g.,flow equalization,
adequate aeration capacity,
parallel units)and well operated.
_.Low quantity of slUdge generated.3.
Some in-system slUdge storage
capacity,eliminating need for
continuous slUdge "asting,4.
treatment and disposal.
5.Capital cost lower than for RBC
and PIC pI ants.
Bulking sludge,hydraulic surges,poor
operating control,etc.,could result
in high effluent suspended solids
level.
Long start-up time;therefore,special
steps must be taken (e.g.,seed plant
with slUdge,recycle unsatisfactory
effluent)•
Require skilled operator (biological
and mechanical training).
Operating cost greater than for RBC (but
less than for PIC plant).
1.Quick recovery from organic and
hydraulic overloads.
1.Start-up time could be long,partiCUlar
ly if toxic chemicals in "aste.
Rotating biological contactor -
Non-permafrost and permafrost regions
where continuous surface water dis·2.
charge is permitted and where moderate
power generation capacity is avail-3.
abl e.
RBC process control is simple.
Law energy requirement compared
to extended aeration.
2.
3.
4.
Require skilled operator (mechanical)
for associated processes.
Require continuous sludge wasting and/or
disposal.
High continuous sludge "asting and/or
disposal.
Physical/Chemical -1.Proven technology (after
extensive modifications).
S.Poor treatment when overloaded,even for
short time periods.
1.Extremely complex.
.......
Permafrost and non-permafrost regions
where highly variable wastewater
characteristics are expected,where
highly trained operators are avail-
able and a high quality effluent is
required.In particular,could be
downstream from a biological treat-
ment plant to produce a very high
quality effluent •
2.Not affected by toxic constitu-
ents such as cleaning solvents
nor significantly affected by
temperature extremes.
3.Instant start up.
2.
3.
4.
Require highly skilled operator
High capital and 0 &M costs.
Large quantities of chemical sludge
generated,requiring additional
handling and disposal.
o Duration,size and location of operation
o Climate
o Geotechnical considerations
Capital and operating costs for a camp system do not command as much
attention as they might in a permanent facility due to many other variables
such as location,unit size,receiving stream,effluent requirements,and
limited time to set up and move on.
It is reasonable to anticipate that no less than secondary treatment will
be required at all camp sites.The major requirements (18 AAC 72)which
need to be met to achieve secondary treatment are as follows.
a
o
BODS--The arithmetic mean of the values for effluent samples
collected in 30 consecutive days may not exceed 30 milligrams per
liter;the arithmetric mean of the values for effluent samples
collected in seven consecutive days may not exceed 45 milligrams
per 1iter;and the arithmetri c mean of the values for effl uer.t
samples collected in a 24-hour period may not exceed 60 milli-
grams per liter.
Suspended Solids--The arithmetric mean of the values for effluent
samples collected in 30 consecutive days may not exceed 30 milli-
grams per liter;the arithm~tric mean of the values for effluent
samples collected in seven consecutive days may not exceed 45
milligrams per liter;the arithmetric mean of the values for
effluent samples collected in a 24-hour period may not exceed 60
-48-
o
milligrams per liter;and for effluent from a lagoon,the arith-
metric mean of the values for effluent samples collected in 30
consecutive days may not exceed 70 milligrams per liter.
~--The values for effluent pH must be kept between 6.0 and 9.0
unless it is shown that inorganic chemicals are not added to the
waste stream as part of the treatment process.l )
r
;1
-
o Fecal Coliform--The arithmetric mean of the values for a minimum
of five effluent samples collected in 30 consecutive days may not
exceed 200 fecal coliform/IOO ml;and the arithmetric mean of the
values for effluent samples collected in seven consecutive days
may not exceed 400 fecal coliform/laO ml.l )
2.5.1 Exploratory and Fly Camps
Small operations will normally use porta-can pails or other similar con-
tainers to receive and transport waste.The disposal point for such
containers must be designed for easy access;otherwise the wastes may not
be deposited according to facility design.The disposal point could be a
landfill site,a facultative lagoon or pond,a wastewater treatment plant,
or a holding tank where the waste is then transported to a treatment
facility by tank truck.Figure 4 illustrates four low-cost treatment
systems.
1 Both pH and fecal coliform limits vary depending on receiving water
I~characteristics.
-49-
,~
SUBSURFACE DISPOSAL:
Underground
-I'SEEPAGE PIT "
'l--.......----~
,'f
SEPTIC TANK &FIELD
Containers
Truck Haul
Collection
System
LAGOONS:
Seepage Pit ~-
Septic Tank ~
...t ...~Underground ....
Distribution !Box or
Dosing t t ,
Chamber...~...~,......
t
NATURAL DEPRESSION (A low area,swamp or lake)
Collection ~Natural Clarification Land Disposal or
System Depression Disinfection Receiving Water"-
~MANMADE
Collection ~Primary ....Secondary ~Clarification Land Disposal or
System
,
Lagoon Lagoon Disinfection Receiving Water
ALASKA POWER AUTHORITY
LOW COST TREATMENT
SYSTEMS (SIMPLE)
FIGURE 4
-
-
Where container wastes are dumped at a landfill site approved by the Alaska
Department of Environmental Conservation (ADEC),they must be covered
daily.If the wastes are deposited in a lagoon or pond,the dumping point
should be designed to prevent erosion of the lagoon dikes and yet allow for
easy access so the waste is deposited in the lagoon and not on the dikes.
Waste disposal pits are constructed by cribbing a hole in the ground and
covering it with a platform containing a disposal hole covered with a
fly-tight,hinged lid.When the pit is full,the platform is removed and
the bunker is covered with the material excavated from a new pit.As with
privies,waste pits are not a desirable form of waste disposal if the soil
is frozen,in areas of fine-grained silts,or when there is a high ground-
water table.
The most satisfactory disposal for container wastes would be at a central
facility where the wastes are a small part of the total waste load to the
facility.A fly-tight closeable box,which is convenient to use,should be
provided on the outside of the building.It must be vandal proof and cap-
able of being thoroughly washed down and cleaned daily.Above all,it must
be aesthetically acceptable and easy to use.
The type of waste dumped at a disposal point could be an important
consideration in treatment plan design even though the quantity (by
comparison to the facility waste)may be small.The waste quite often
contains a high concentration of deodorizers such as formaldehyde and
phenols,which could affect biological treatment processes.It also may
-51-
contain plastic bags and other solid wastes and wnl be very high in BOD
(up to 1000 mg/l)and low in hydraulic loading.
The break even point when the loading or facility requires more
sophisticated treatment is summarized in Table 14.
2.5.2 Small and Intermediate Camps
Sma 11 and intermedi ate camp wastewater di sposa 1 systems generally range
from truck-haul,lagoon-disposal systems to more complex piped-collection
and treatment plant facilities.The majority of the discussion on
treatment system options follows in Section 2.5.3.This section addresses
primarily dispos~l of truck-hauled wastewater.
The disposal point for truck hauled waste should be in a heated building
with a "drive through If design to make the unloading time as short as
possible.The building should also provide heated storage for the vehicles
while not in use or for repairs.Where the disposal point is at a landfill
or lagoon,a ramp or splash pad should be provided to prevent erosion and
still allow the vehicle to deposit the wastes wel1 within the lagoon or
landfill.Any plastic bags used to contain wastes should go through a
slitter to empty the contents.The contents then flow to a wet well where
they can be pumped to a 1a900n or to a treatment pl ant.The bags can
be incinerated or land filled depending upon state approval.
The building in which the vehicles are stored and/or emptied should also be
equipped with water for flushing and cleaning the tanks.The washwater
-52-
-
TABLE 14
WASTEWATER DISPOSAL
ADEC GUIDELINES
GRAYl4ATER
Pressurized LandDisposal~/
Non-
pressurized Land
,~Disposal~/
SEWAGE
Nonwaterborne 2/Cat-Hole-4/
Alternate
LandDisposal~/
LandDisposal~/
Buria1 3/-4/Alternate
Plan Review 5/
Disposal~/
Burial
Alternate 4/
Plan Review 5/
Plan Review 5/
Waterborne
Chemically
Treated
Approved Plan Review 5/Plan Review 5/
Wastewater
Dump Station.
Burial and
Land Disposal
Prohibited.
Plan Review 5/
Footnotes:1/LAND DISPOSAL -Land disposal of graywater is permitted as
shown subject to the following conditions:
a.Discharges must be at least 100 feet,measured horizontally,
from any natural or man-made lake,river,slough,stream or
coastal water of the state.
b.There is no drainage to water courses or standing water.
c.No puddling ocurs on the surface after 15 minutes.
d.Discharges should,to the extent possible,be limited to
already disturbed and/or gravel areas.
~/CAT-HOLE -Cat-holes are for individual one-time use and should
be located in remote areas at least 100 feet from any streams or
~'
-
-
TABLE 14 (Continued)
water bodies and well away from campsites or other areas
frequented by people.All fecal material and tissues should be
buried in a small hole,covered with soil and packed down.The
vegetation,sod,tundra mat,etc.,should then be replaced and
the area left as if no one had used it.
If BURIAL -Slit trenches,latrines,straddle trenches,pit privies,
etc.,are permitted where site-specific and seasonal conditions
allow.The type and size should meet the anticipated use.Use
of these facilities is subject to the following conditions:
a.Located at least 100 feet,measured horizontally,from any
natural or man-made lake,river,slough,stream or coastal
water.
b.Constructed so that surface water drainage is away from the
pit or trench.
c.Vertical separation between the bottom of the trench or pit
and the highest water table elevation is 4 feet.
d.May not be constructed within 75 feet of the top,measured
horizontally,of a cut or fill bank exceeding 6 feet in
height.
e.Pits and trenches should be located,where possible,in
already disturbed areas.
f.Pits or trenches filled with wastes to a point 1 foot from
the surface must be closed out.
g.All pits or trenches must be disinfected with 1 ime (or
equivalent)prior to close out.
h.Close out requires filling to ground level with successive
layers of earth packing each layer down before adding the
next one.The filled pit should then be mounded over with
at least 1 foot of dirt.
i.Pits and trenches not needed for overwi nter use must be
closed out prior to freeze-up.
if ALTERNATE -Alternate disposal methods not requiring permits or
approvals include:
a.Backhauling in holding tanks or suitable containers to
approved camp stations or wastewater treatment systems.
Examples:Vault toilets;porta-johns;camper holding tanks.
chemical toilets.'
b.Incinerator type toilets.Electric or propane.
c.Use of existing approved wastewater systems.
..-
....:
-
TABLE 14 (Continued)
52 §./PLAN REVIEW -As indicated on the chart,this is the level at
which plans for wastewater disposal must be submitted to the
department and reviewed on a case-by-case basis.This includes,
but is not limited to,subsurface and surface discharge system,
septic tanks,infiltration systems,french drains,lagoons,
soakage pits,stack injection,etc.
§./NONRECURRING USE -Permanent facil ities or repeated use of the
same site requires plan review by AOEC .
.-
--
should drain to the wet well where it can proceed to treatment.Extreme
care must be taken to prevent a cross-connection with the water system.
2.5.3 Intermediate and large Camps
The following sections discuss the various components (illustrated on
Figure 5)necessary to complete the treatment process for intermediate and
large camps and end up with a safe effluent.Units will be presented from
the raw water end to the polishing end.Changing the order of placement of
some units will affect the treatment efficiency and dictate design
modifications accordingly.For instance,it may be preferrable to aerate a
flow equalization tank prior to comminution so that less settling will take
place.Or,screening prior to equalization may eliminate a greater amount
of solids prior to treatment.Or,comminution followed by aeration in the
equalization tank may enhance an activited sludge process.Use of a lagoon
for treatment may eliminate the need for any pre-treatment.The selected
procedure will depend upon the appearance of the wastewater as it enters
the plant,its relative elevation,the extremes of flow variation and need
for process pumping.
Elevation differences due to natural topography should be maximized in
order to minimize the need for pumping.Extreme care must be taken during
the design process to stabilize flows and not overdesign pumps for peak
situations.It may be preferriible to use several equivalent pumps in
parallel rather than to use one or two very large pumps.Several pumps are
more flexible,provide backup during maintenance,and are more cheaply
replaced or repaired.
-56-
1 1 1 -1 --~l 1 1 I 1 J J 1 1 I 1 }1 1
Clarification
"7 Dllinfectlon
Sicondary
Treatment
Primary
Treatment
Flow
Equallutlon
4 Aeration
8
........ll.".--I Temponry I ........
Wastewater
Storage
Greale Trap
\",.,.('~~o(;~('e(·...\('~
201l-Separator
Kitchen
10llwSklmmero(I I.'I.~Je~'"~,~",,....,
...Vehicle Wash
ED o o 00 o §)
Greale Trap
Oil-Skimmer
TREATMENT
OPTIONS
*Scraens
Bar Racks
*Mlcroltralner
Commlnutor
Aeration
Mixing
Aaratlon
PhYllcal/Chemlcal Chlorine
Activated Sludge *O~one
Extended Aeration
*Rotatlng Biological Contactore
Land DIIPoul
Dllcharge to
Receiving Water
0 [!][!]§)
Grit Removal Tank Decant Aerobic
Oil-Separator Lagoon Filter Prell *Anaeroblc
*Vacuum
*Centrlfuge
[!]
Incinerate
Burial
*Compoltlng
*Needl Study for Camp Application
ALASKA POWER AUTHORITY
HIGH-COST TREATMENT
SYSTEMS (COMPLEX)
FIGURE 5
,-
-
-
-
-
-
-
The system should be designed to accommodate peak flows.The necessary
equipment and bypasses should be incorporated to continue operation in the
event a portion of the system fails.Redundancy in pumping,treatment and
storage are essential.
2.5.3~1 Pre-treatment
Pre-treatment is considered to be any method of treating or conditioning
raw wastewater in order to improve its treatability or to protect
equipment.Pre-treatment processes applicable to camps include grease
removal,screening,comminution and pre-aeration.The required types of
pre-treatment facilities are determined by the requirements of the main
treatment facility.For example,lagoons may not require any type of
pre-treatment,whereas physical/chemical plants may require grease removal
and screening.
Grease removal facil ities are particul arly important for effi ci ent
operation of mechanical treatment plants.Grease traps,septic tanks
and/or air flotation tanks are necessary,since large quantities of grease
can seriously overload downstream treatment facilities as well as
contribute to breakdowns of mechanical equipment.
The first unit operation encountered in wastewater treatment plants,
assuming grit chambers,grease traps and oil skimmers are in place up-
stream,is the filtering operation or screening.Coarse screening devices
in sewage treatment consist mainly of bar racks,which are used to protect
-58-
"""
pumps,valves,pipelines,and other appurtenances from damage or clogging
by rags and large objects.
Suspended particles greater than!inch can be removed more economically by
screening than by other unit operations.Fine screens of the disk or drum
type are generally used.The high content of oil,grease,cooking fats,
etc.at camps frequently interferes with the success of fine screening
devi ces.They may warrant additional considerati on,dependi ng upon camp
influent quality,since they are simple devices and low energy users.
Sufficient elevation difference may allow gravity straining or sieving
before any pumping is required.The minimum rotary screening opening
should not be so small as to clog quickly and require frequent maintenance.
Screen openings of 2 millimeters appear to be desirable.Alternatively,a
screen with automatic cleaning (perhaps backwash)could be considered.
Comminution is another alternative.With comminution,larger solids are
ground into smaller pieces which remain in the treatment system but are
small enough so as not to adversely affect downstream equipment.Comminu-
tion is commonly used with extended aeration plants.
Pre-aeration is a process which may be used to make septic or high strength
wastes more amenable to subsequent treatment by reducing the initial high
oxygen uptake rate of the wastes.Aerated flow equalization tanks can
serve this purpose.Pre-aeration is not required for physical/chemical
systems.
-59-
2.5.3.2 Temporary Wastewater Storage
Provisions for emergency storage for mechanical treatment plants may be
required by regulation for the following reasons:
o To retain satisfactory wastewater effluent during periods of
plant malfunction.This effluent can be recycled to the plant at
a controlled rate once the cause of malfunction has been
rectified.
o To receive the entire raw wastewater f1 ow if,for some reason,
the plant is not functioning.
o To further assist with the smooth operation of a biological
treatment plant during start-up by permitting recycle of organics
to the plant.
A minimum holding period of 5 days is recommended for emergency holding
ponds.Longer than 5 days may be desirable in some cases after
consideration of a number of factors such as geotechnical conditions,
season(s}of operation,dependability of the operator and treatment
process,length of operating time,and the condition and downstream uses of
the receiving water.
-60-
-
-
2.5.3.3 Flow Equalization
One of the most important design considerations for any mechanical treat-
ment plant is flow equalization.Because treatment plants function best
over given flow ranges,it is desirable to dampen peak hydraulic loadings
which commonly occur in the morning and evening and at such other times as
may be characteristic of a particular camp.It is suggested that flow
equalization tanks should provide 12 hours retention at the average daily
flow;however,this could vary depending on the expected diurnal flow
variations.The tanks must be aerated to prevent solids deposition and to
keep the contents homogeneous and aerobic.Transfer of the liquid from the
flow equalization tank to the downstream treatment units should be accom-
plished at a uniform rate (set at average daily flow or,for phys-
ical/chemical plants,at the plant capacity).Many sewage pumps provide
flows much in excess of the average flows expected at cal)1ps.If special
precautions,such as a progressive cavity pump with variable speed drive or
an air lift pump in a constant head tank,are not taken,the purpose of
flow equalization wilT be undermined.
2.5.3.4 Primary Treatment
Primary treatment SUbstantially removes all floating and settleable solids
from wastewater by such means as flotation and settling.Flotation is used
p'f'imarily in the treatment of wastewater containi ng 1arge quantiti es of
industrial wastes that carry heavy loads of finely divided suspended solids
and grease.For camp wastewater,the degree of solids reduction achievable
by primary treatment is not well documented.Typically,normal domestic
-61-
wastewater would be reduced 50 to 65 percent in suspended solids and 25 to
40 percent in BODS by primary settling.It is expected that B00 5 reduc-
tions for camp wastewater might be at the lower end of this range because
of the higher-than-normal soluble BOD 5 fraction in camp wastewater.
Primary treatment as the only level of treatment is generally not accept-
able in Alaska.A permit variance would have to be requested.The permit
application would need considerable documentation as to the ability of the
receiving water or land mass to assimilate all of the waste in an
environmentally acceptable fashion.
The simplest primary treatment facility is the short retention lagoon,with
a retention time ranging from 3 to 30 days,and depth varying from 10 to 20
feet.The liquid and accumulated sludge in this type of lagoon undergo
anaerobic decomposition and consequently can be malodorous at times.
Particularly obnoxious odors can occur when the water supply has a high
sul fate content resulting in reducti on of sul fates to hydrogen sul fi de
under anaerobic conditions.Consequently,it is usually advisable to site
short retention ponds in the prevailing downwind direction and as far as
practicable (at least 100 feet)from the serviced population.
2.5.3.5 Secondary Treatment
Secondary treatment means that method of removal of dissolved and colloidal
materials which produces an effluent with the characteristics described in
Section 2.5.Secondary treatment can be accomplished by means of long
retention lagoons,aerated lagoons or by various types of mechanical
-62-
treatment plants.Mechanical treatment plants discussed in this manual are
limited to extended aeration,rotating biological contractors (RBC)and
physical/chemical (P/C)processes.
Lagoons
Wastewater 1agoons can provi de one of the simp1 est,most cost-effective
methods of wastewater treatment.The capital cost of constructing a lagoon
is low provided that geotechnical conditions are suitable.The operating
cost is low since specially trained personnel are not required,little time
is required for operational control,and power requirements are very low or
nil (except for aerated lagoons).
Lagoons must be water-tight unless the effect of seepage can be shown not
to adversely affect any groundwater or nearby waterbodi es.Furthermore,
water-tightness is desirable for protection of inlet appurtenances against
freezing due to low water levels during cold weather.The interior of the
lagoon should be lined with in situ clay,or compacted mixed (off site)
bentonite,or an impervious membrane.
There are two basic types of secondary lagoons applicable to workcamps:
long retention and aerated.The long retention lagoons are also often
termed facultative lagoons or oxidation ponds.Since the ponds are often
covered by ice and are anaerobic for such a long period of time,the term
"long retention"more accurately describes such lagoons~
-63-
The following design suggestions should be considered for long retention
lagoons treating camp wastewater:
~,
c A separate,short primary retention pond,preceding the long
retention lagoon,would improve the overall performance by
removing readily settleable and floatable organic solids.
Suggested holding time for the primary cell is 5 days.
o Minimum of two long retention cells would be preferred.
o In terms of BOD,a loading of 0.5 pounds per day per 1000 square
feet should not be exceeded.
o Complete winter retention plus at least 3 months or longer
operation of the long retention cells under aerobic conditions
are necessary to produce a secondary quality eff1uent.The ponds
must have full sunlight throughout the day to promote effective
treatment.
o Long retention lagoons should be over-sized by as much as 50
percent to ensure that complete winter retention is provided in
case of flow under-estimation.
o Maximum cell depth should be 7 to 10 feet considering ice cover,
freeboard and liquid operating depth.
-64-
-
-
o The lagoon should be sited as far away from human habitation as
possible,preferably at least 1000 feet downwind because of
potential odor problems.
o Provisions for flow measurements should be provided.
There appears to be no precedent for this type of lagoon system treating
camp wastes.However,there are a great many Canadian villages,large and
small,that have demonstrated good low-cost results.A lagoon system is
less subject to fluctuations in flow but toxins can still cause upset to
the biological stability.
Aerated lagoons are another type of secondary lagoon.Winter conditions in
Alaska at the remote camp sites could create such difficult conditions that
treatment by normal lagoon process may not lag far behind the more
expensive aeration system in producing acceptable quality effluent.It is
suggested that a minimum of two cells with a total of 30 to 40 days reten-
tion time,followed by a polishing pond,are required.The aeration system
for the lagoon must be selected carefully to handle the maximum oxygen
demand,which usually occurs in the springtime when water temperatures warm
up and accumulation of undigested winter sludge exert an internal oxygen
demand in addition to the applied demand.
Extended Aeration
Extended aeration is a modification of the activated sludge treatment
process.It has been used extensively in treati ng workcamp wastewater
-65-
-
....
-
because of its high degree of stability for a wide variation in wastewater
flow rate and strength.This biological process requires a trained
operator or close supervi si on to avoi d upset.A schematic di agram of a
package extended aeration plant is shown on Figure 6.
Package extended aeration plants have been used at a number of construction
camps in Canada and the U.S.A.Performance data on some of these are
summarized in Table 15.Suggested design criteria and operating
requirements for extended aeration plants are outlined in Table 16 .
It should be noted that the recommended aeration tank loadings in Table 16
would result in an average retention time of 60 hours.The much less
conservative approach taken at camps in Al!aska (tanks provi ded 24 hours
retention at the design average daily flow rate)is not recommended.
A characteristic problem with extended aeration plants is their long
start-up time,which is usually 30 days before an adequate biological mass
is built up in the aeration tank.This problem can be minimized or
circumvented by applying one or a combination of the following procedures:
,....
o Operate the aeration tank with no aercltion for 1 week or as long as
generated odors remain bearable.Biological solids will settle out
and be effectively retained in the system.Aeration tends to break
solids up,producing a pin-point,hard-to-settle floc when mixed
liquid suspended solids (MLSS)concentr'ation is low.By accumulating
solids in the aeration tank before the aeration system is turned on,
better flocculation of solids is promoted and start-up time is
decreased.
-66-
Temporary bypass ...Emergencyrstorage ....
I ..~"
Returj flow •t+Overflow
Unsatisfactory elnuent
Effluent
disposal
,-----.....,
L.1 Sludge ••L........SludgeIPldewateringj"""disposal
"-----........
DecantSolids
disposal·
I
Waste gross soNds
-...
r-------.,
R SCreening Aerated ftow ~'Aeration ~'Effluent I r-!Y-aw f-LJ...or I-L........equalization lank L.JJ..Clarilfer
sewage -".comminution -".tank IUniform r-JJI"I disinfection 1
L.-.....,,~,....I flow L.--......t-..J L_-'-.J
Return sludge 'Waste slUdge
,r (periodic)
•Not required with comminution
Note:Dolled lines indicate optional processes
*,.Required it incineration is usee;!for sludge disposal
,-
ALASKA POWER AUTHORITY
.....
SCHEMATIC OF EXTENDED
AERATION PROCESS
FIGURE 6
I i J ~1\1 iJ ~-l l l )
(
l )..-1
TABLE 15
PERFORMANCE OF EXTENDED AERATION PLANTS TREATING CAMP WASTEWATER
.....
TABLE 16
SUGGESTED DESIGN CRITERIA AND OPERATING REQUIREMENTS
FOR EXTENDED AERATION PLANTS TREATING CAMP WASTEWATER 1
DESIGN
....
-
Aeration tank loading -
(dual units)
Flow equalization
Oxygen requirement
Oxygen transfer efficiency
Mixing requirement
Clarifier surface loading rate
Positive sludge return
Sludge handling facilities
0.24 kg BOOs/m 3 daily average @ 20°C
0.48 k9 B00 5/m 3 daily maximum @ 20°C
Separate or in-system flow equalization
2 kg O2 transferred/kg BODS applied
3-5%depending on air diffusers,tank
geometry,etc.
Sufficient air or energy must be sup-
plied for aeration tank mixing
16 m3/m 2 daily average
29 m3/m 2 hourly peak
20 -200%of average daily influent
flowrate (normally set at 100%)
0.5 kg suspended solids per kg
B00 5 removed
~OPERATION
-
.-
Measure mixed liquor dissolved oxygen,settleability and note color daily.
Adjust air flowrates as required.
Scrape hopper-type clarifier daily to ensure solids do not hang-up on the
wall s.
Waste sludge as required to maintain mixed liquor suspended solids (MlSS)
in the 3000 -6000 mg/l range,approximately .
o Design a variable capacity unit or dual units sized to keep the
food-to-microorganism ratio in a favorable range for start-up.
o
o
Discharge poor quality effluent to the emergency holding pond and
recycle settled solids to the head of the plant.
Import activated sludge solids from a mature treatment plant.
-
,~
o Add an artificial substrate to build-up the bacterial population
faster.
Through prudent start-up procedures,it should be possible to achieve 80
percent BODS reduction after a I-week operating period and 90 percent after
a 2-week period.
Rotating Biological Contactor
Rotating biological contactors (RBC)usually consist of plastic discs
mounted on a horizontal shaft across a tank.The discs are slowly rotated
with approximately 40 percent of their surface area submerged in wastewater
in the tank.Biomass adheres to the discs,grows in the presence of oxygen
and metabolizes organic matter in the wastewater.When the attached
biomass on the discs becomes thick,portions of it slough off the discs
into the wastewater.The wastewater effluent from the RBC tank is
clarified to remove the sloughed biological solids.These solids must be
-70-
-
removed regularly as sludge and treated and/or disposed of separately.A
schematic diagram for an RBG and auxiliary components is presented on
Figure 7.RBG systems have not been used extensively at campsite.s.
Additional study is needed to take advantage of the concept1s simplicity
and low energy demand.
Pretreatment of the raw wastewater before addition to the RBC is essential
to remove grease whi ch coul d coat the di scs and decrease performance;to
remove larger solids which could clog the discs;and to remove smaller,but
settleable,solids which are not efficiently removed by the discs
themselves.
RBG plants,excluding auxiliary equipment,are simpler and more economical
to operate than extended aeration pl ants.However,they usually have
higher capital costs than the equivalent extended aeration plants and
auxil iary equipment requirements may be more extensive than for extended
aeration.
As shown from the limited data on Table 17,experience with RBC's in
treati ng camp wastewater is 1imited.Tentative design criteri a for RBC
plants treating camp wastewater are presented in Table 18.Typical RBC
problems are attributed to:
o
o
Organic overloading due to a higher~than-expected camp popu-
lation.
Cleaning compounds in the raw sewage.
-71-
..-
TABLE 17
PERFORMANCE OF RBC PLAfHS TREATING CONCENTRATED WASTEWATER
Disc Disc
Type of Disc Tot~l Rota-Number Influ-
Type of Pre-treat-Type of Diam Ar~a tion of Para-~'"t
Waste ment Evaluation (m)(m )(rpm)Staqes me,ter (mqll )
Performance
Effl u-Removal
ent
(mqlll (%)
Total
Drqanic
Loa~inq
q/m Id
Tot~'
Hydraulic
LOiI~in!l
11m Id
~,Workcamp
Workcamp
Hydro-
Screen
On-site
plant
2.0 790 1.5
1.5
4
4
COD 3315a 956 72
SS 2048a 422 79
VSS '1746"276 64
Oil &,186a 16 96
Crease
COD Il62 a 291 66
55 :114"71 77
VSS :!22"51 77
Oil &36
a 10 72
Grease
BOD 1543-1080 25-66 92-97
CDD5 1271-1753 66-256 92-96
SS :152-600 32-114 55-94
VSS :152-560 32-114 55-93
12
13
a Influent strenqth before pre-treatment
b Actual loadinq on discs would be less because effect of pre-treatment not included
TABLE 18
TENTATIVE DESIGN CRITERIA AND OPERATING REQUIREMENTS
FOR REe PLANTS TREATING CAMP WASTEWATER
,~
DESIGN
Heated enclosure
Flotation tank for grease removal
Primary settling (or equivalent)
Intermediate clarification
RBe hydraulic loading
RBe organic loading
Intermediate clarifier overflow rate
Final clarifier overflow rate
Number of stages
-essential
-consider
-essential
-desirable
-40 11m 2 hourly peak
-20 11m2 daily average
(for 600 mgll waste)
-24 g BOD/m 2 hourly peak
-12 g BOO/m 2 daily average
3 2-40 -80 m 1m Iday
-24 m3/m 2 daily average
3 2-32 m 1m hourly peak
- 4 minimum
OPERATION
Must ensure that excess grease or cleaning compounds do not enter plant.
o Grease content of the wastewater can be considerably higher than
200 mg/l (causes coating of discs with excessive grease).
Possible remedial action that can be taken during design includes:
o
o
o
Provisions for recycling some of the effluent.
Provisions for adding influent to both the first and second
stages to reduce the shock of high BOD loading.
Pre-aeration in an aerated flow equalization tank to reduce
oxygen demand.
Physical/Chemical Plants
Physical/chemical (P/C)treatment plants,as the name implies,rely on
physical and chemical processes to achieve organic reductions.PIC plants
include various combinations of the following processes:comminution,
screening,clarification,flocculation,coagulation,filtration,carbon
adsorption and pH adjustment.PIC plants require large quantities of
chemicals and produce large quantities of chemical sludges requiring
further treatment and disposal.-The main advantage of PIC units is their
ability to handle a wide range of wastewater characteristics without plant
upsets,provided that chemical additions and re~ction times are sufficient.
Toxic chemicals have little or no effects.
-75-
.-
-
Considerable experience has been'gained with PIC treatment plants~but they
require continuous operator attention.Figure 8 illustrates one design for
removal of organics with a packaged treatment plant.Table 19 summarizes
the design parameters for the unit.
An essential part of any chemical or chemically aided precipitation system
is stirring or agitation to increase the opportunity for particle contact
(flocculation)after the chemicals have been added.If the agitation is too
vigorous,the shear forces that are set up will break up the floc into
smaller particles .
Chemical precipitation in wastewater treatment involves the addition of
chemical s for the expressed purposes of improvi ng pl ant performance and
removing specific components contained in the wastewater.In the past,
chemical precipitation was used to enhance the degree of suspended solids
and BOD removal (1)where there were seasonal variations in the concen-
tration of the sewage,(2)where an intermediate degree of treatment Wil,S
required~and (3)as an aid to the sedimentation process.
More recently~interest in chemical precipitation has been renewed because
(1)it can be used effectively for the removal of phosphorus.and (2)it
can be combined with activated-carbon adsorption to provide complete
wastewater treatment ~bypassing the need for bi 01 ogi cal treatment and ~at
the same time,p~oviding more effective removal of the organics in
wastewater that are resistant to biological treatment.For example~the
residual COD after chemical precipitation and carbon adsorption is about 10
to 20 mg/1iter~whereas the residual COD after biological treatment is
about 100 to 300 mg/liter.
-76-
e"h,enl to
inrillration '3gOOl1
I----
/
Firslslage
llocculalor:
t,.Ij 1 ..,.--.....,
~r..[~~"'.,\..,0111~··~·~I 1\~~::·"·:">i:\"l
L __--.::::..l-~-rJ::::=7_......::::;;;..---'--=;......:::-_·"./''------'
Second stage First ~tage : \Second slage Mulli media Chlorine conlact/
1I0cculalot lube selller ',tube setl/e1'liller backwash Slorage
Polym8l'~lj """"\
SupemalMI to aerated'
equaizalion lanI<\
GraVity lhlckener
.,15
!E
OJ toju
&i
.toe;!:,30
<to
••,,",,":I~,.,~II-+'-H
aerated 'I
equaization ,
tank l1~p,d
mix
.....
..-
-
Legend
_Forward flow
---Backwash
Thickened sludge
10 incinerator
Backwash 10 aeraled
equa~zalion tank
,-
ALASKA POWER AUTHORITY
SCHEMATIC OF PIC
TREATMENT PLANT
FIGURE 8
I~
TABLE 19
SUMMARY OF DESIGN PARAHETERS FOR PIC UNIT
UNIT
OPERATION
Gross Solids Reduction
andlor Removal
Aerated Equalization Tank
-Blower Capacity
-Minimum Detention Time
Rapid Mix Chamber
Flocculator
First Stage Clarifier
Second Stage Clarifier
Multi-Media Filter
-Filtration Rate
-Backwash Rate
Chlorine ContactlBackwash
-Storage Tank Detention
Time
-Sludge Dewatering Device
Sludge Incinerator
DESIGN PARAMETERS
Comminutor or Rotary Screen
100 1jfm 3/min.
5 hours
Air-agitated with 6-second
detention time
Two units in series each
containing a variable speed
vertical shaft paddle mixer -
20 minute detention time
Overflow rate thro~gh 60°tube
settlers of 94 11m Imin
Overflow rate thro~gh n°
settlers of 61 11m Imin
200 l/m~/min
770 11m Imin
30 minutes
Center feed gravity thickener
with 2surface loading rate of 69.3
kg/m Iday and with a sludge
blanket detention time of 8 hours.
Pathological Burner
,.....
l-"t!
Many different substances have been used as precipitants.The most common
ones are listed on Table 20.The degree of clarification obtained depends
on the quantity of chemicals used and the care with which the process is
controlled.It is possible by chemical precipitation to obtain a clear
effluent,substantially free from matter in suspension or in the colloidal
state.
The chemicals added to sewage in chemical precipitation react with
substances that are either normally present in the sewage or are added for
this purpose.
Many reactions with other substances in sewage may take place.Each site-
specific wastewater will have its own characteristic anomalies.Once they
are identified,remedial action can be taken.The repeating indicators
will give adequate notice of upcoming problems.
2.5.3.6 Disinfection
The final stage in treatment prior to releasing the effluent is disin-
fection,the sel ective destruction of di sease-causi ng organi sms.A11 of
the organi sms are not destroyed duri ng the!process.Thi s differenti ates
disinfection from sterilization,which is the destruction of all organisms.
In the field of wastewater treatment,disinf2ction most commonly is accom-
plished through the use of (1)chemical agents,(2)physical agents,(3)
mechanical means,and (4)radiation.
-79-
TABLE 20
CHEMICALS USED IN WASTEWATER TREATMENT
-Chemical Formula
Molecular
Weight
-.
*Number of bound water molecules will vary from 13 to 18.
...-.-
An ideal disinfectant would have to possess a wide range of characteris-
tics.It is also important that the disinfectant be safe to handle and
apply,and that its strength or concentration in treated waters be
measurable so that the presence of a residual can be determined.
Chemical agents that have been used as disinfectants include phenol and
phenolic compounds,alcohols,iodine,chlorine and its compounds,bromine,
ozone,heavy metals and related compounds,dyes,soaps and synthetic
detergents,quaternary ammonium compounds,hydrogen peroxide,and various
alkalies and acids.
Chlorine is the most commonly used disinfectant throughout the world.In
dry powdered compounds (HTH)it can be mi xed with water for use at camp
sites;chlorine residual limits are based on the characteristics of the
receiving water.Liquid chlorine gas,aHhough efficient,could be too
hazardous to transport and store at remote locations.
2.5.3.7 Sludge Thickening
Depending upon the treatment process,it may be necessary to dewater the
sludge to some cost-effective level.Decanting,which merely amounts to
letting the sludge settle quietly in its own tank until the water rises and
then drawing off the mixed liquor suspended solids and sludge separately,
is the most economical beginning point.Other alternatives to review are
vacuum filtration,filter press,and centrifuge.
-81-
-
-
2.5.3.8 Sludge Digestion and Disposal
Continued aeration of the sludge in an activated sludge process will digest
it to relatively safe condition.The by-product water generated can be
recirculated and portions of the sludge may be needed to maintain
biological reactions in the system during low camp population periods.
Anaerobic digestion of sludge has not been investigated in field
situations.Perhaps the advantages of fuy"ther volume reduction,stable
solids,and methane gas production do not offset its space requirements and
need for heat.The inert products of anaerobic digestion could possibly
provide a nutrient rich revegetation material.
Standard practice finds most sludges,greases,residues,etc.burned in the
camp incinerator with the ash disposed of at a landfill.
2.5.3.9 Effluent Disposal
Several methods of wastewater disposal into soil are or have been prac-
ticed,including absorption field disposal of septic tank or aerobic
treatment effluents,direct burial in pits,disposal in ice crypts or snow
sumps,and dumping and covering in a landfill.The presence of,and depth
and thickness of,permafrost,the type of soil and its percolation rates,
and the frost penetration depth will influence the possibility of land
application of effluent.
Land application of wastewater requires maintenance of the soil permeabil-
ity.In some cold climate areas this may be possible through special
design.However,many areas are unsuitable.The presence of permafrost
-82-
..-
wi 11 1imit verti ca 1 movement of the wastewater,and wi nter freezeback of
the active layer may prevent horizontal movement.It may be possible to
design a suitable system in areas of thawed zones which do not completely
freeze.Thermal protection for an absorption field should be designed for
the worst winter conditions,minimum or no snow,and low temperatures.
Another approach warranti ng cons i derati on is the use of a retenti on-l and
disposal system,making use of land disposal during the warmer parts of the
year and retention through the winter.In general,land disposal is
similar and subject to the same constraints as land treatment.The major
difference is that land disposal systems are mainly concerned with getting
the effluent into the ground and away from the site.The major concern is
that the effluent moves in an acceptable direction and does not present a
hazard to public health.
Discharge of treated wastewater into wetlands,lakes,ponds,or rivers
requires detailed site evaluation to determine potential impacts on aquatic
resources.The type of recei vi ng waterbodi es and the effl uent standards
which pertain to each specific operation are also important factors in the
type of outfall structure designed.
Ponds are generally shallow,with depths up to 7 feet.Surface areas range
from a few 1,000 to a few 10,000 square feet,and retention times are often
extreme 1y long,1 to 6 months.Freeze depths may vary from 2 to 5 feet.
Ice thickness can be estimated mathematical"ly by assuming worst conditions
of no snow cover and minimum heat input.The use of a pond to receive
treated wastewater would effectively convert it to a polishing lagoon.
-83-
..-
Fencing and posting to that effect is required.Regulatory agencies must
be consulted before this approach is pursued.
lakes may have the ability to absorb a greater volume of waste\A/ater.
Important considerations include surface area,depth,volume-inflow
relationships,nutrients,flora and fauna,and benthic populations.
Effluent quality,especially with regard to microorganisms,must be high if
there is a potential for fishery or recreational use of the lake.
Northern streams and rivers are the most common receiving waters for
wastewater.Flow,ice depth and movement are the most important factors to
be considered.Dissolved oxygen conditions through the winter and down-
stream uses are of particular importance in selection of the type of
outfall structure to be used.
The use of natural swamps for treating or polishing wastewater has received
considerable attention in recent years.Swamp discharge has been practiced
in several places in the North;however,detailed studies have been lim-
ited.It is important to design the outfall diffuser for maximum disper-
sion into the swamp.
Where possible,ocean discharge is desirable.Normally,the ability to
absorb quality variations is very great.If initial dispersion by outfall
design and tid~l movement is not obtained,however,wastewater will concen-
trate on the surface,because fresh water and sewage are 1ess dense than
salt water.The result is a visible slick.The major advantage of sea
disposal is dilution.The design of the outfall must consider ice movement
due to tidal action,currents,nearby rivers and wind action.
-84-
CHAPTER 3 -SOLID WASTE
Solid wastes generated during the construction of Power Authority projects will
vary from domestic refuse to large bulky items such as discarded equipment
parts.Early planning for the management of solid wastes~including handling,
storage,and disposal,is essential to minimize health hazards and adverse
environmental impacts.
The basic objectives of the solid waste management program for a project include:
o Preventing or minimizing the environmental impacts associated with the
management and disposal of solid wastes (land,water and air pollu-
tion,worker health and safety~aesthetics~etc.)
o Resource conservation (reclamation~reuse,minimization of land
requirements,etc.)
o Sound engineering practices
o Compliance with governing regulations
-!o Response to public attitudes
o Achieving these objectives in the most economical manner for a given
situation.
Factors to be considered during the planning phase for project waste management
include:
o Types of wastes
a Volumes of wastes
-85-
o Method of treatment and disposal
Incineration
Landfill
-Storage for salvage
Reuse on site
-Public solid waste facilities
o Soil type
o Climatology
o Permafrost conditions (Figure 9)
o Size and life of the facility
o Economics of alternative waste management systems
o Environmental concerns or constraints
o Geographic location
o Regulatory constraints
Project permitting requirements should be reviewed at the planning stage of
solid waste management projects.This review should contain the elements set
out in Section 2.1.
To implement a solid waste management plan,an organizational structure will be
,~
developed that will define the individuals and their delegated responsibilities
to ensure that the project will be in compliance with applicable permits,codes,
and regulations.
Federal law prohibits "open dumping"as that term is defined in the Solid Waste
Management Act.The act imposes minimum solid waste regulations pertaining to
-86-
,~
..-
-
.....
NOT-TO-SCALE
........Southern limit of continuous permafrost
Southern limit of discontinuous permafrost
Mea nan nuaI air is 0 the rm [0 C)
ALASKA POWER AUTHORITY
PERMAFROST IN ALASKA
FIGURE 9
-
,~
open dumping (40 CFR 257).These regulations must be satisified in addition to
any state solid waste requirements.
3.1 TYPES OF WASTES
The sources of solid wastes generated during exploration,construction,or
operation of a project are readily identifiable during the planning phase
of the activities.Figure 10 displays one method of delineating types of
waste products.Special note should be made of the project location when
determining waste types since activities at a remote,controlled-access
project will differ from those where worke!rs have access to publ ic ser-
vices.Wastes for personnel support are usually institutional wastes
generated by controlled use of products and commissary services.A 500 to
700-man camp at a remote site in Alaska will generate 2 to 3 tons per day
of diverse waste products (not including clearing debris or
overburden/spoil materials).The typical physical composition for these
wastes is as follows:
-
.....
1200-1500 "I b/day
200-500 lb/day
2000-4000 lb/day
Municipal type (paper,cardboard,food and
beverage cans,bottles,etc.)
Food scraps and cooking wastes
Garage,warehousing and repair wastes (equipment
repair metals,pa nets ,strapping,form 1umber,
etc.)
.....
-
The Alaska Department of Environmental Conservation uses a camp-generated
solid waste rate of 7.9,lbs/person/day for'design review purposes.Camp
-88-
]1 -1 ))1 1 j j 1 1 1 -j 1
Grout
Spol1s
Equipment Parts
55-gal Drums
Strapping
Concrete
Abandoned Vehlc'es
Ash
Waste Generation
Residences
Kitchens
Garage/Servtce Shops
Construct Ion Site's
Paper
Trees and stu
Putresclbles
Cans/C.rtons
PI
Camp Wastewater
Sedlment.tlon Ponds
£lJU IJlIIIent lIuhwa ter
I
-fTRA1'SPOIlTI
Service/Garage wastes
Sludges
Solvents
Greases .
Fue'Cle.nup M.terlals
Radioactive Mat.rl.ls
l(ASH ~we WERATIOH
I
I
~efer to Project
:rue I &lIazardous
~aterla1s ~lgt.Manu,l Refer to Project Fuet
•'111.1\'"1.11'rIlUI,.L;);),lIaurdou5 Materh',
:-.>lAHDFfll oE-------~Management Manu,t
•OISPOSAl-------·-----------,I I.I I I I'-- - - - - - - -~RECLAHATION/RECYC!.[<It-- -I i I :
I I 'I
I I I I
I I '"V ~.-)SPECIAL HANDLING UITH~-_lind or W.ter Incineration Reclam.tton/t DISPOSAL AT AN APPROVED SITE .j.R"y,"0'
Ash Reuse
I_%S Z;;r:::==.iUl __·...__::::::._~.....__,._..__
•Regulated Through Agency Codes
ALASKA POWER AUTHORITY
CRITERIA FOR WASTE
,
MANAGEMENT ANALYSIS i
FIGURE 10
.-
.-.
wastes can be further classified as 86 percent combustible and 14 percent
non-combustible •
3.2 TREATMENT ALTERNATIVES
There are four general practices for solid waste treatment and disposal in
Alaska:incineration,landfill,reclamation for reuse,and salvage (haul
back).Table 21 shows waste products with storage and disposal techniques .
This table is intended only as general guidance.Waste classification and
appropriate storage and disposal practices should be determined on a case-
by-case basis in accordance with applicable federal,state,and local laws.
3.2.1 Incineration
Incineration is the acceptable method of treating putrescible wastes at
remote sites to prevent food products from attracting wildlife.The
objective of the incineration process is to control combustion of the waste
to produce a residue which is not degradable and contains no combustible
material.The residue (ash)then requires disposal.Advantages and
disadvantages associated with this disposal technique are as follows:
Advantages:
o Proven acceptable method in Alaska
o Provi des an inert,envi ronmenta 11 y-acceptab 1e,end product for
disposal
o Treats wastes as generated --less storage space required
o Eliminates leachate of organics at sites
-90-
Stora~e
SI -nimal proof container
S2 -Open container
S3 -Covered container
S4 -leak proof container (area)
S5 -Drums
....
TABLE 21
SOLID WASTE
DISPOSAL TECHNIQUES
SOLID WASTE CATEGORY STORAGE DISPOSAL ALTERNATIVES
Paper C3 S3 01,2,6
Plastics C3 S3 01,2,6
Cardboard C3 S3 01,2,6
Wood C3 S2 01,2,6
Food Bottles &Cans Cl,4 SI 01,2,5
Food Packaging C1,3,4 SI 01,2
Food Wastes C4 Sl 01,2
Tires C2 S2 01,3,5
Batteries C2,5 S4 05,8
Equipment Parts Cl S2 03,5
Oil Drums C2,5 S4 03,4,5,8
Incinerator Ash Cl S3 01
PVC Pipe C2 S2 01
Oil Filters C3,5 S4 D2,8
Trees &Slash C3 S2 D1,6,7
Solvents &Paints C3,5 S4 02,8
Greases C2 S4,5 01,3,5
Used Oils C3,5 S4,5 02,3,5,8
X-ray Wastes C3,5 S4,5 04,8
Categories
Cl -Non-combustible
C2 -Non-burnable (regulated by codes)
C3 -Combustible
C4 -Putrescible
C5 -Toxic/hazardous (as defined by
either federal or state regulations)
Disposal
01 -la;:ldfill
02 -Incineration
03 -Storage at landfill
04 -Return to vendor
05 -Salvage,reuse
06 -Open burn
07 -Chip
08 -Special regulations
o Waste reduction (70 to 75 percent reduction of camp wastes)
o Reduces animal and bird scavenging
May contribute to air quality degradation
High energy demand
Requires trained operators
Hazardous due to combustion of unknown solid wastes
Heated building required in areas of extreme low temperatures
labor intensive
Disadvantages:
Most expensive of processing systems in terms of capital and
operating costs
0
~
0
0
0
~
0
0
0
and/or adverse climatic conditions
o Segregation of wastes required
o Incinerator ashes require special handling,hauling,etc.
3.2.2 landfill
Figure 11 depicts a typical site design for a landfill and Figures 12
through 14 illustrate three common operational plans for the placement of
solid wastes.The area method (Figure 12)is used when trenches cannot be
excavated.Wastes are spread in long,narrow strips on the surface of the
land in a series of layers that vary in depth from 16 to 30 inches.An
earthen levee or berm is constructed against which wastes are compacted.
The ram\1l:method (Figure 13)is employed "'Ihen cover material is scarce.
Additional soil cover must be hauled in for both the area and ramp methods.
The trench method (Figure 14)is suited to areas where an adequate depth of
-92-
....
DRAINAGE DITCH
--------x----?---~-...,
><
.-......1Il..ACCESS ROAD
(-ELEV.)/
"'------......---
ALASKA POWER AUTHORITY
TYPICAL LANDFILL
DISPOSAL SITE
FIGURE 11
E art hen ----~«::;~."'-
levee or berm ~~~I~~Z;~::::::
Partially completed
second lift
ALASKA POWER AUTHORITY
SANITARY LANDFILLING
AREA METHOD
FIGURE 12
""'"
-
Daily cell covered with
earth from base of ramp
Compacted
solid wastes
~~'''orking face
ALASKA POWER AUTHORITY
SANITARY LANDFILLING
RAMP METHOD
FIGURE 13
Fence
Working 1ace--_0!iiEi,~~~~
ALASKA POWER AUTHORITY
SANITARY LANDFILLING
TRENCH METHOD
FIGURE 14
-
-
-
cover material is readily available.Cover material is obtained by
excavating an adjacent trench.
3.2.2.1 Site Selection and Design
Preliminary screening and ultimate selection of a landfill site should be
based on the results of a site(s)survey(s),results of engineering design
and cost studies,and an environmental assessment.The selection team
should be comprised of the design engineer,biologist,hydrologist,geolo-
gist,sanitary engineer,and regulatory personnel.Factors that must be
considered include:
o Land Availability--The use of the land area around a project site
may be affected by zoning restrictions,public resistance or
project boundaries.Usually landfill sites are located on lands
designated by a project for use as a borrow site,material
storage area,etc.to permit the maximum use of an area without
expanding demands on the land.
o Haul Distance--The shorter the haul the more economical the solid
waste transport costs.Alchough minimal haul distances are
desirable,project policies to use previously disturbed sites may
negate this cost-effectiveness criterion.
o Soi 1 Conditi ons--The soi 1 at the site is the most important
single aspect for judging site suitability because of its role as
the interface between the waste and the groundwater.The soil's
-97-
r-
I
.....
characteristics and availability as cover material must also be
considered.
There is usually information on file with a local resource agency
on soils in an area.However this data may be scarce or not
available in Alaska.Soil borings can provide data prior to
design.This data can be reviewed using soi 1 interpretation
\
sheets such as found in Tables 22 through 24 from the U.S.
Department of Agriculture,Soil Conservation Service.
Approximately 1 cubic yard of cover material will be required for
every 4 to 6 cubic yards of solid wastes.Table 25 provides a
guide for cover material requirements.The cover material should
be less permeable than the soil under the landfill (Figure 15).
o Cl imate--Winds,rainfall and snow cover must be known to ade-
quately assess a landfill site with respect to area requirements,
design parameters and physical layout .
o Ground and Surface Water Data--The control of site drainage and
the protection of surface/ground water is important in the
selection process.Prospective sites must be appraised for the
abil ity to control drainage to and from the area to prevent
leaching of waste constituents to ground or surface water and to
maintain all-weather access roads.The site must be designed to
prevent the washout of cover wastes.
-98-
TABLE 22
APPLICATION OF SOIL INFORMATION
DAILY COVER FOR LANDFILL
..-
LIMITS RESTRICTIVE
PROPERTY GOOD FAIR POOR FEATURE
.....
1.USDA TEXTURE ICE PERMAFROST
2.DEPTH TO BEDROCK (IN)60 40-60 40 DEPTH TO ROCK--3.DEnH TO CEMENTED PAN (IN)60 40-60 40 CEMENTEO PAN
4.l)UNIFIED SP,SW SEEPAGE
SP-SM,
;,~SW-SM,
GP.GW,
GP-GM,
GW-GM·-1),2),3)USDA TEXTURE5.Cl,SICl,SIC,C TOO CLAYEY
SC
6.l)USDA TEXTURE LCOS,lS,S,FS,TOO SANDY
lFS.COS,SG
VFS
1""".7.1)t2)UNIFIED OL t OH,HARD TO PACK
CH,MH
8.1)t4)COARSE FRAGMENTS (PCT)25 25-50 50 SMAll STONES
jliii'iO 9.1),4)FRACTION 3 IN
(WT PCT)25 25-50 50 LARGE STONES
10.SLOPE (PCT)8 8-15 15 SLOPE-I 11.DEPTH TO HIGH WATER TABLE
(FT)+PONDING
3.5 1.5-3.5 1.5 WETNESS
12.l)UHIFIED PT EXCESS HUMUS
13.LAYER THICKNESS (IN)60 40-60 40 THIN lAYER
14.l)SOIl REACTION (pH)3.6 TOO ACID
15.2)SALINITY 16 EXCESS SALT
(MMHOS/CM)
(0-60"}
16.1),2)SODIUM
ADSORBTION RATIO 12 EXCESS SODIUM
OR GREAT GROUP OR PHASE (HALIC,
NATRIC,
ALKALI
PHASES)
17.CARBONATES 5)EXCESS LINE
~I~Thickest layer between 10 and 60 inches.
2 Disregard (1)in all Aridisols except Salarthids and Aquic sUbgroups,(2)all
Aridic subgroups,and (3)all Torri great groups of Entisols except Aquic
)subgroups.
,~~i)If in ~aolinitic family,rate one class better if experience confirms.
Sum (100-%passing No.10 sieve)and fraction less than 3 in.Use dominant
condition for restrictive feature.
5)IT amount of carbonate s so high that is restricts the growth of plants,rate
·POOR-EXCESS LIMEn.
~
I
TABLE 23
APPtICATION OF SOIt INFORMATION
SANITARY LANDFILL (TRENCH)
mIlO
LIMITS RESTRICTIVE
PROPERTY GOOD FAIR POOR FEATURE
I""""
1.USDA TEXTURE ICE PERMAFROST
2.FLOODING NONE RARE COMMON FLOODING
3.DEPTH TO BEDROCK (IN)72 DEPTH TO ROCK
4.DEPTH TO CEMENTED
PAN (IN)CEMENTED PAN
THICK 72
THIN 72
5.l)PERMEASILITY 2.0 SEEPAGE
(IN/HR)
(BOnOH LAYER)
6.DEPTH TO HIGH WATER
..-TABLE (FT):+PONDING
APPARENT 6 WETNESS
PERCHED 4 2-4 2 WETNESS
7.SLOPE (PCT)8 8-15 15 SLOPE
8.1).2).3)USDA TEXTURE Ct.SC,SIC.C TOO CLAYEY
SICL-9.3)USDA TEXTURE LCOS.LS.COS.S TOO SANDY
LFS.PS.VPS.
LVSF SG
10.3)UNIFIED OL.OH.PT EXCESS HUMUS
11.4)FRACTION 3 IN (WT PCT)20 20-35 35 LARGE STONES
""""'I 12.l)SODIUM ADSORPTION
RATIO (0-40")OR 12 EXCESS SODIUM
GREAT GROUP OR (HALIC.
NATRIC.-ALKALI
PHASES)
13.SOIL REACTION (pH)3.6 TOO ACID-(ANY DEPTH)
14.SALINITY (MMHOS/CM)16 EXCESS SALT
(ANY DEPTH)
15.DOWNSLOPE MOVEMENT 5)SLIPPAGE
16.DIFFERENTIAL SETTLING 6)lJNSTABLE FILL
I~·1j11
II:DiSregard (1)in all Aridisols except Salorthids and Aquic subgroups,(2)all
:Aridic subgroups,and (3)all Torri great groups of Entisols except Aquic
2)subgroups.
~3)If in kaolinitic family,rate one class better if experience confirms.
4)Thickest layer between 10 and 60 inches.
)Weighted average to 60 inches.
SIf the soil is susceptible to movement downslope when loaded,excavated,or
)wet.rate "SEVERE-SLIPPAGE".
5.If the soil is susceptible to differential settling,rate "SEVERE-UNSTABLE
FILL".
-
-
l)Oisregard (1)in all Aridisols except Salorthids and Aquic subgroups,(2)all
Aridic subgroups.and (3)all Torri great groups of Entisols except Aquic
)subgroups.
2 If the soil is susceptible to movement downslope when loaded,excavated,or
)wet.rate "SEVERE-SLIPPAGE".
3 If the soil is susceptible to the formation of pits caused by the melting of
)ground ice ~hen the ground cover is removed,rate "SEVERE·PITTING".
4 If the soil is susceptible to differential settling,rate ·SEVERE·UNSTABLE
FILL".
------------~----~-
-
TABLE 25
DAILY AND FINAL COVER MATERIAL REQUIREMENTS
Daily Cover Material Requirements
(Based on 6-inch daily cover)
Refuse Intake
(long tons
per day)
In Place
Volume
@ 1000 lbs
per yds 3
(yards 3)
Total Area
of Daily Cell
(yards 2)
Cell Depth in Feet
6 ft 8 ft 10 ft
Total Daily Volume
of Cover Material
(yards 3 )
Cell Depth in Feet
6 ft 8 ft 10 ft
.f"""
i
25 56 28 21 17 5 4 3
50 112 56 42 34 9 7 6
100 224 112 84 67 19 14 11
200 448 224 168 134 37 28 22
500 1120 560 420 335 94 70 56
750 1680 840 629 502 140 105 84
1000 2240 1120 839 671 187 140 112
Final Cover Material Requirements
Acreage
25
50
100
150
200
250
300
Final Cover Material
Required (yards 3 )
80,700
161,400
322,800
484,200
645,600
807,000
968,500
-
-
ImmH ACCEPTABLE SOILS
PERCENT SAND
I
ALASKA POWER AUTHORITY
;
SOILS SUITABLE FOR
COVER MATERIAL
FIGURE 15
-
In regions of above-average precipitation,as experienced in many
areas of Alaska,special attention is required to divert drainage.
Shoul d interface soil conditions warrant,two indirect methods
for control of site drainage can be assessed:impermeable barrier
or drainage way.The peak rate of flow which needs to be diverted
is a function of rainfall,land treatment,soil type,slope,and
antecedent moisture conditions.Drainage channels most commonly
used are earthen swales and split corrugated metal pipe.Recom-
mendations for permissible velocities for bare earthen channels
are found in Table 26.Final earthen swales can be grassed or a
stone center ditch can be added to protect against erosion.
o Permafrost Soils--A sanitary landfill is generally not a
practical method of disposal in permafrost areas.Excavation is
extremely difficult and may create additi onal problems through
destruction of the active layer.Cover material sources other
than permafrost soils must be available,often necessitating
expensive transportation charges.
o Environmental Constraints or Considerations--Project construction
and operation in Alaska involve evaluation of existing environ-
mental conditions prior to initiation to respond to the many
environmental concerns unique to the state.Federal,state,and
local regulatory und permitting requirements may dictate the type
of solid waste management techniques selected by the Power
Authority.Environmental issues are enhanced due to the lack of
previ ous development activiti es'at remote 1ocati ons.Proximity
-104-
-----_.~---~,,_._----,--------
TABLE 26
PERMISSIBLE VELOCITIES FOR BARE EARTHEN CHANNELS
.-
Soil Texture
Sandy and sandy loam (non-colloidal)
Silt loam (also high lime clay)
Sandy clay loam
Clay loam
Stiff clay,fine gravel,
graded loam to gravel
Graded silt to cobbles (colloidal)
Shale,hardpan and coarse gravel
Source:Soil Conservation Service (1970)
Maximum
Velocity
(ft/sec)
2.5
3.0
3.5
4.0
5.0
5.5
6.0
-
--\
o
to eagles'nests,anadromous fish waterways,wildlife habitat and
migration routes,parks,etc.may preclude solid waste
activities.
In accordance with State of Alaska solid waste regulations
(18 AAC 60),landfills should be surrounded with animal-resistant
fencing.The design and construction techniques used should be
developed in consultation with applicable regulatory agencies.
Final Use of the Site after Completion--A determination,during
the planning phase of a project,of the ultimate use of a com-
pleted solid waste site will result in a more effective design.
In many instances,the landowner/manager may dictate how the site
will be rehabilitated or how permanent slopes and drainage
patterns will be constructed.Federal and state law may require
installation of groundwater monitoring wells to be operated after
site closure.Effective liaison with project planners will
result in cost-effective site design to eliminate labor-intensive
requirements to mold the area to fit designated needs after
completion of the project.
-
-
o Access Roads--The chief goal in designing access to the site
should be to minimize interference between solid waste vehicular
traffic and other project activities.The roads,which should
have a trouble-free surface (Table 27),should be designed to
direct trucks to the working face and out as quickly as possible.
Because haul roads at the landfill location (working face)are
-106-
1 •1 "'1 1
TABLE 27
1 1 J "10
I l J J 1
ROADWAY SOILS CHARACTERISTICS
Viluel at Foundltlon Vilue la Base Potent hI CO"'Prelllbf1 Ity Unit Dry
JIIlen Not Subject to DI rectly Under Frost end Drlln~ge Weight
Major Divisions N'lle Frost Action W..rina Surface Action EXDlnalon Chulcteriatici ComDactlon EoulDment Lb.Per Cu.Ft
Crave 1 or alndy grovel,Excellent Good None to very All10at none Excellent Crowler type tractor.r~bber tired 125-1110
well orlded IUght eoulDment.Iteel .....eeled roller
Gravel or Iln~y grovel,Good to excellent Poor to fair None to very A11KJlt none Excellent Crawler type tractor.rubber tired 120-130
GRAVEL I poor lY or aded IUght equipment Iteel wheeled roller
AND Cravel or landy gravel Good Good Hone to very AlllOlt none Excellent Crawler type tractor.rubber 115-135
GRAVELLY uniformlY oraded aUaht tt red eoul pment
SOILS Silty gravel or Illty Good to excellent hlr to good Slight to Very alight Fair to poor Rubber tired equipment.sheeplfoot 130-1115
IIndv Drivel lIedlum roller close control of mollture
COARSE Clayey grovel or cl.yey Good Poor Slight to Slight Poor to pr,ctlc,lly Rubber tired equipment.120-1110
CRA INED IIndy gravel lied I l1li IlllDervloul Iheepsfoot roller
SOILS Sand or gravelly ,ond.Good Poor None to very AllllOlt none Excellent Crawler type tractor.rubber 110-130
well graded 11IQht ti red equl pment
SAND Sand or gravelly lind.hlr to good P,por to not None to very AlllOlt none Excellent Crawler type tractor.rubber 105-120
AND poorly graded lultlble slight tired equipment
SANDY Sand or grlvelly lind,Felr to good Not lultlble None to very AlllOlt none Excellent Crawler type trlctor.rubber 100-115
SOILS uniformly graded alight tire eQuilll1lent
Silty sand or silty Good Poor Slight to Very Ilight hlr to poor Rubber tired equipment.sheeplfoot 120-135
gr ave lly lind hlah '-roller clole control of moisture
Cllyey sand or clayey Felr to good Not suitable Slight to Slight to Poor to pr.ctlcoll~Rubber tired equipment.105-130
gravelly lind high lied I II1II Impervloua sheepsfoot roller
Silts.sandy slltl,grovelly Felr to poor Not suitable Medhllll to Slfght to hlr to poor Rubber tired equipment.sheeplfoot 100-125
sllh or diatomaceous 10111 very high Iledlllll roller close control of molature
lOW Lean cl.ys.sandy cloYl,Felr to poor Not lui table Medium to Medium Prlctlcel1y Rubber tired equipment.100-125
COHPRESSI-or oravellv claYS hlah imeervious ..sheeDsfoot roller
PILITY Org.nlc silts or leon Poor Not lui table Medhlll to Medium to Poor Rubber tired equlplllent,90-105
FINE LL<50 org.nlc clayS hlah hlah sheepsfoot roller
CHAINED Micaceous clay.~r Poor Not aultable Medlllll to High Fair to poor Rubber tired equipment,90-100
SOILS diatomaceoul soils very high "."sheepsfoot roller
HIGH Fat clays Poor to very poor Not sulhble Medlllll High Practicolly Rubber tired equipment.90-110
COMPRESS 1-impervious sheeDsfoot roller
BrLIlY Fat organic clays Poor to very poor Not suitable Medium High Prlctlcilly Rubber tired equipment.90-105
LL )50 Impervious sheeplfoot roller
PEAT AND OTHER Pelt.humus and other Not lui table Not suitable Slight Very high Fair to poor Compaction not practical -
fl8ROUS ORGANIC SOILS
-
-
-
o
constantly being built and buried,fill for dressing and repair
must be available.Public access to the site must be controlled
to minimize health and safety hazards.On projects adjacent to
pub 1ic thoroughfares,gates shoul d be pl aced across the access
road to regulate site use.
Cell Design and Construction--To estimate the amount of land area
required for preliminary planning purposes,the following.example
is provided:
Solid waste generation =7.9 lbs/person/day l)
Compacted density @ landfill =800 lb/yd 3
Average depth of compacted solid wastes =8 ft
Generation rate =3300 people x 8 lb/person/day
2000 lb/ton
=13.2 tons/day
Volume required/day =13.2 tons/day x 2000 lb/ton
3 800 lb/yd3
=33 yd /day
Area required =(33 yd 3 /day)(365 days/yr)(27 ft 3/yd 3 )
(10 ft)(43,560 ft 2/acre)
=.74 acres/yr
The actual site requ i rements will be greater (va ri es 20 to 40
percent)than the value computed because additional land is
required for site preparation,access roads,etc.
-
1)Not allowing for incineration/volume reductions.
-108-
~,
."",!,,.
Once volumes have been estimated and site capacities have been
determined,the sequence for filling must be selected.Figure 16
shows a typical filling sequence using compacted solid wastes
with an earth cover.
o Equipment Requirements--The design of the landfill can only be
realized using the right equipment and personnel.Equipment
should be chosen to fit the plan.Equipment is required for
spreading and compaction of solid wastes as well as for excavat-
ing and hauling cover materials.On a small site,the operation
will probably use one piece of equipment (crawler or rubber-tired
tractor with the fo 11 owi ng acces sari es : a dozer blade,1 to 2
yard front-end loader,and trash blade)for the landfill opera-
tion with an occasional "assist"from an additional piece of
equipment to procure and stockpile cover material.Table 28
provides a guide to the general capabil ities of major items of
landfill equipment.
o Fire Fighting Technique--Proper cell construction will prevent
underground fires from spreading.When fires occur,the tech-
nique most frequently consists of digging out the area and
rolling out the smouldering contents.Appropriate fire ex-
tingUishers should be carried on equipment at all times.
o.Litter Control--The use of covered vehi cl es for transport of
solid wastes such as paper,cardboard,ashes,etc.is a most
effective control of litter.Movable litter fences are required
-109-
.....
.....
'Ii.:
II.
...
-.t:-a;.~()..
.t:
6 in intermediate
earth cover
2 ft final earth
cover on slope face
2:1 or 3:1 typical slope
ALASKA POWER AUTHORITY
SECTIONAL VIEW OF
A SANITARY LANDFILL
FIGURE 16
~l J ]]]1 )1
TABLE 28
I 1 i I I 1
EQUIPMENT SELECTION GUIDE FOR MULTIPLE UNIT SITES
Rubber
Tired
Tractor
Track Drawn
Purpose loader Dozer Compactor Scraper Scraper Dragline
Solid Waste Spreading A A A 0 0 0
Handling Compaction A A A 0 0 0
Cover Material Excavate Cover A A 0 A*A*,A
Handl ing Spreading A A A B B 0
Compaction A A A 0 0 0
Shaping B B B B B 0
Hauling
300'or less A A B A 0 C
300'-1000'0 0 0 A B C
More than 1000'0 0 0 0 A C
A =Excellent Choice
B =Secondary Choll'')
C ="In-Combini'ltion Only"Choice
o =Not Applicable or Poor Choice
*=Scrapers may require loading assistance in tough soils and adverse weather conditions.
Source:Eldredge (1975).
Motor
Backhoe Truck Grader
0 0 0
0 0 0
A 0 0
0 0 B
0 0 0
0 0 A
C C 0
C C 0
C C 0
--
-
o
at the site when landfills are subject to high winds.The fence,
pes iti oned downwi nd of the worki ng face,wi 11 catch airborne
trash resulting from the off-loading operation from the open
working face pri or to cover.Because wi nds are vari ab 1e,three
or four fences should be provided.
Unloading Area--To control dumping,the width of the unloading
area should be limited to twice the width of the compaction
vehicle,or 16 feet.The fill area should be controlled to keep
vehicles in safe areas and,where possible,working at the base
of the loading face.
-
3.2.2.2 Advantages and Disadvantages
Advantages and disadvantages of landfill disposal are as follows:
Advantages:
o Most economical method of solid waste disposal if land is avail-
able
o
o
o
Can receive a variety of solid wastes with the exception of toxic
and hazardous wastes requiring special disposal procedures
Flexible;increased quantities of solid wastes can be processed
Operation is oriented toward typical and readily available
constructio,i'equipment
Disadvantages:
o Site selection limited due to pristine land areas,permafrost
-112-
......
conditions,drainage patterns,cover materials,etc.
Slow biodegradation of putrescibles and organics in Alaska
Waste segregation control difficult--attracts birds and animals
Impacts land and water resources
Cover materials of effective quality may not be available
Requires daily maintenance covering;may require groundwater or
soil monitori ng
a landfill settling requires periodic maintenance
o Stringent permit requirements
3.2.3 Reclamation for Reuse
Many of the constituents of refuse,particularly metals and paper,can be
recycl ed.However,because of the heterogeneous compos i ti on of wastes,
sorting processes are complex.For many components,the cost of separation
and return to market exceeds their value.Power Authority projects,with
ancillary camp support,do not lend themselves to mechanical sorting due to
the nature of the refuse.However,reuseabl~wastes could be segregated at
the source of generation.Reuse,reclamation and salvage markets must be
available for this alternative.Generally,storage and bulk transport of
materials in large volumes may offset the high costs of long hauls and make
the products more attractive to a buyer.
One option that should be assessed during the development of any incinera-
tion plan is energy recovery for heating buildings or water for camp use.
Figure 17 depicts a typical schematic for an incinerator with a heat
exchanger.In evaluating this alternative,consideration should include
-113-
,~
-
,....,
Flue Gas
"
Heat Exchanger
Steam..
IIIIC ....Hot Water
Boiler
Return Water..
Grate Condensate
Refuse
Residue
ALASKA POWER AUTHORITY
INCINERATOR FOR ENERGY
RECOVERY
FIGURE 17
-
the high initial costs along with any associated energy savings.The
design engineer must also consider that the incinerator will have IIdown
time ll and that auxi 11 ary sources of energy for any heat recovery use
systems must be provided.
3.2.4 Salvage
Salvage materials require additional space for storage either on the solid
waste disposal site or at a specially designated site designed for adequate
control and access.Salvageable materials known to accumulate at project
sites in Alaska are off-road equipment parts,tires,batteries,oil drums,
scrap metals and vehicles.
3.2.5 Special Treatment
Construction-related solid wastes are classified under state law as II ru b-
bish ll
•They may include spoil materials,lumber,plumbing and electrical
parts,equipment parts,etc.State law l"equires special treatment for
non-processed wastes since the wastes cannot be processed through an
incinerator nor should they be mixed with the regular landfill wastes due
to their bulk,physical characteristics,etc.which cause voids and
improper compaction in a landfill.
State and federal regulations control the disposal of hazardous wastes and
to date there are no authorized disposal sites in the State of Alaska.
Incineration of these products requires special approval from EPA and ADEC.
It is recommended that these solid wastes be stockpiled for recycling,
-115-
-
..-
-
.-
returned to the manufacturer,or transported to an EPA-approved treatment
and disposal site in accordance with state and federal regulations.The
fuel and hazardous materials BMP manual should be consulted for particul~r
application of hazardous waste requirements.
Special attention must be given to the design of the storage areas for
hazardous wastes to comply with applicable federal and state regulations.
(Information on design of these storage areas and special handling required
by state and federal regulations is contained in the BMP manual on fuel and
hazardous materials.)Such areas should be enclosed to control access and
be posted for workers'safety.All solid waste personnel assigned to these
areas must receive proper training in the handl ing and transporting of
these wastes .
3.3 AT-SOURCE HANDLING
Provisions for handling solid wastes at the source before collection should
be included in the design criteria.For large-scale projects,grinding,
sorting and compaction will reduce the storage requirements.The types and
capacities of the containers used depend on the characteristics of the
solid wastes to be collected,and the space available for the placement of
containers.Debris boxes,compaction containers,and garbage cans must be
located in areas with direct collection truck access.Special considera-
tions for storage areas should be made for sites where heavy snow loads
preclude effective transfer of wastes without adequate cover over contain-
ers.Putrescible wastes,if stored for collection outside (If buildings,
-116-
must be stored in animal-proof containers.Pressurized cans must be
separated from other refuse that will be treated by incineration.
3.4 TRANSPORT OF SOLID WASTES
Collection and transport of wastes can be by covered garbage trucks to
prevent waste from escaping from the vehicle,satellite vehicles for easy
mobility and access,open dump trucks for discarded equipment and timber,
or hauled container systems.Table 29 provides typical data for vehicle
selection for large collection systems.Design of the facility must
include adequate space allowance for solid waste transport.Transporters
shoul d be 1i censed or authorized to accept and haul the waste materi a1
submitted for transport.
3.5 OCCUPATIONAL SAFETY AND HEALTH
A program of worker training must be initiated prior to waste facility
operations to provide information and instruction on the waste management
plans per design specifications.The train'ing must include information on
waste characteristics with particular emphasis on any toxic or hazardous
wastes pertinent to the operation.Federal and state law require
procedures to protect workers from dust or fumes inhalation;corro-
sive/dermatitis hazards;physical hazards such as noise,fires,etc.;and
mechanical hazards (i.e.vehicular accidents).
The training program should include maintenance requirements,personal
hygiene and protection,materials handling,waste monitoring,operational
-117-
J 1 --J ])
TABLE 29
1 1 1 J 1 1 )J
TYPICAL DATA ON VEHICLES USED FOR THE COLLECTION OF SOLID WASTES
COLLECTION VEHICLE TYPICAL OVERALL COLLECTION VEHICLE DIMENSIONS
Available
container or truck Number With indicated
body ca~aciti es of container or truc~Width Height Length
Type (yd )axles body capacity (yd )(i n)(i n)(i n)Unloading method
Hauled container systems
Hoist truck 6-12 2 10 94 80-100 110-150 Gravity,bottom opening
Tilt-frame 12-60 3 30 96 80-90 220-300 GravitYt inclined tipping
Truck-tractor trash-trailer 12-50 3 40 96 90-150 220-450 Gravity,inclined tipping
Stationary container system
Compactor (mechanically loaded)
Front loading 20-45 3 30 96 140-150 240-290 Hydraulic ejector panel
Side loading 10-36 3 30 96 132-150 220-260 Hydraulic ejector panel
Rear loading 10-30 2 20 96 125-135 210-230 Hydraulic ejector panel
Compactor (manually loaded)
Side loading 10-37 3 37 96 132-150 240-300 Hydraulic ejector panel
Rear loading 10-30 2 20 96 125-135 210-230 Hydraulic ejector panel
,.,...
procedures,and record keeping.
The waste management organizational responsibilities,including each
worker's role,must be well-defined for effective waste management.
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CHAPTER 4 -REGULATORY ANALYSIS
Solid waste management has become increasingly more controlled as public health
agencies,conservationists,and concerned citizens have pressed for more
government control.The following agencies are delegated responsibility:
Federa 1
River and Harbor Act of 1899
Solid Waste Disposal Act of 1965
Clean Water Act,Section 404
Resources Recovery Act of 1970
Resource Conservation &Recovery Act
of 1976
("Cradle to the grave"regulatory
requirements and documentation)
o Toxic Substance Control Act
o Hazardous Materials
Transportation Act
o Occupational Safety &
Health Act
State
Department of Defense (CaE)
Department of Health Education &
Welfare
Environmental Protection Agency
Department of Interior
Environmental Protection Agency
Environmental Protection Agency
Department of Transportation
OSHA,NIOSH
Liquid &Solid Waste Regulations:Dept.of Environmental Conservation
18 AAC 60 Solid Waste Management
18 AAC 15 Administrative Procedures
18 AAC 50 Air Quality Control
18 AAC 70 Water Quality Standards
18 AAC 72 Wastewater Disposal
18 AAC 74 Water and Wastewater Operator Certification and Training
18 AAC 75 Oil and Hazardous Substances Pollution Control
AS 46.04.030 Oil Discharge Contingency Plans
Occupational Safety and Health:Department of Labor
8 ACC 61 Occupational Safety and Health
Land and Water Use:Department of Natural Resources
11 AAC 53 Easements and Rights-of-Way
11 AAC 58 Leasing of Lands
11 AAC 93 Water Management
11 AAC 96 Miscellaneous Land Use
-120-
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