United States
Environmental Protection Office of Water EPA 811-D-93-001
Agency 4603 April 1993
&EPA SMALL WATER SYSTEM ~~
BYPRODUCTS TREATMENT AND
DISPOSAL COST DOCUMENT
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I
SMALL WATER SYSTEM BYPRODUCTS
TREATMENT AND DISPOSAL COST DOCUMENT
' ; Prepared for:
U.S. Environmental Protection Agency
Office of Ground Water and Drinking Water
Drinking Water Standards Division
401 M Street S.W.
Washington, D.C. 20460
Prepared by:
DPRA Incorporated
E-1500 First National Bank Building
332 Minnesota Street
St. Paul, Minnesota 55101
April 1993
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Notice
This document has been reviewed in accordance with U.S. Environmental Protection Agency
policy and approved for publication. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
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TABLE OF CONTENTS
1.0 INTRODUCTION . ......;. 1
1.1 Background ,..'.. ,...:... .'.,.. 1
1.2 Purpose and Scope .....'.... 1
1.3 Water Treatment Processes . . . . : ; . . 3
1.4 Byproducts Generated , 7
1.5 Byproducts Management Options Overview 7
2.0 BYPRODUCT CHARACTERIZATION . . 9
A " '. :
2.1 Introduction 9 .
2.2 Chemical Coagulation and Filtration 9
2.3 Lime Softening , 11
2.4 Ion Exchange .. . '. . . 12
2.5 Reverse Osmosis . . . . ,. . . 14
"2.6 Byproduct Densities . . .: 15
2.7 References . . 15.
3.0 COST ASSUMPTIONS ....:............ 17
3.1 Introduction ; . . ....;.... 17
3.2 Capital Cost Assumptions .> 17
3.3 Operation and Maintenance Assumptions 19
3.4 ' Total Annual Cost Assumptions . . . : .21
3.5 Cost Components Excluded . . : . . . 21
3.6 Cost Equations ....... . 22
3.7 Calculating Byproduct Management Costs .....'. . 23
4.0 GRAVITY THICKENING . 28
4.1 Technology Description .28
4.2 Technology Applicability and Limitations . .' 29
4.3 Cost Components . . . . .29
4.3.1 Design Assumptions 29
4.3.2 Capital Components 30
4.3.3 Operation and Maintenance Components 31 .
4.3.4 Cost Components Excluded 31
.''..'
4.4 Gravity Thickening Cost Equations ; 31
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TABLE OF CONTENTS .
(continued) ,
Page
5.0 CHEMICAL PRECIPITATION' 34
5.1 Technology Description 34
5.2 Technology Applicability - 35
5.3 . Technology Limitations , 35
5.4 Cost Components 36
\ ,
5.4.1 Design Assumptions 36
5.4.2 Capital Components 36
5.4.3 Operation and Maintenance Components 37
5.4.4 Cost Components Excluded 38
5.5 Cost Equations ....'.......- .' . V . . . 38
6.0 MECHANICAL DEWATERING 40
6.1 Technology Description 40
6.2 Technology Applicability 41.
6.3 Technology Limitations . . . 41
6.4 Cost Components . . . i 43
/ i, * *
6.4.1 Design Assumptions 43
6.4.2 Capital Components 43
6.4.3 Operation and Maintenance Components 44
6.4.4 Cost Components Excluded . . . 45
6.5 Cost Equations ; : '. 45
7.0 NONMECHANICAL DEWATERING . ..'. . . 47
7.1 Sand Drying Bed Description . . . ''. .47
7.2 Technology Applicability 48
7.3 Technology Limitations 48
7.4 Sand Drying Bed Cost Components 49
7.4.1 Design Assumptions ......< . 49
7.4.2 Capital Components . 51
7.4.3 Operation and Maintenance Components : 51
7.4.4 Cost Components Excluded 52
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TABLE OF CONTENTS
(continued)
Page
7.5 Sand Drying Bed Cost Equations 52
7.6 Storage Lagoon Description . 54
7.7 Technology Applicability 55
7.8 Technology Limitations -.. 56
.7.9 Storage Lagoons Cost Components . , 56
7.9.1 Design Assumptions 57
7.9.2 Capital Components ,..:.... 57
7.9.3 Operation and Maintenance Components : . . 58
7.9.4 Cost Components Excluded . . 1 58
V. « ' , , '
7.10 Lime Softening Storage Lagoon Cost Equations . . . -. 59
' . ,\ '
8.0 EVAPORATION PONDS : . . '.. . . 61
8.1 Technology Description .61
8.2 Technology Applicability 62
8.3 Technology Limitations .......... .' 62
8.4 Cost Components ;......... 63
V
8.4.1 Design Assumptions 63
., 8.4.2 Capital Components , ......", 64
8.4.3 . Operation and Maintenance Components .... .... 65
8.4.4 Cost Components Excluded ...-.' '. 65
'' .
8.5 Cost Equations 66
' 9.0 POTW DISCHARGE 68
9.1 Technology Description ....." 68
9.2 Technology Applicability 69
9.3 Technology Limitations : 69
9.4 Cost Components .......;. . . . ; 70
9.4.1 Design Assumptions - 70
9.4.2 Capital Components . . ..." 71
9.4.3 , Operation and Maintenance Components ........: 72
9.4.4 Cost Components Excluded . 72
9.5 Cost Equations 72
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TABLE OF CONTENTS
(continued)
9.5.1 500 Feet of Discharge Pipe 72
9.5.2 1,000 Feet of Discharge Pipe . 73
10.0 DIRECT DISCHARGE 75
10.1 Technology Description 75
10.2 Technology Applicability 76
10.3 Technology Limitations .' ;....'.... 76
10.4 Cost Components ; .77
10.4.1 Design Assumptions . 77
10.4.2 Capital Components 77
10.4.3 Operation and Maintenance Components 78
10.4.4 Cost Components Excluded . . 79
10.5 Cost Equations 79
10.5.1 500 Feet of Discharge Pipe 79
10.5.2 1000 Feet of Discharge Pipe 80
' 10.5.3. 500 Feet of Discharge Pipe with a"
Holding Tank or Lagoon ...'.: 81
10.5.4 1,000 Feet of Discharge Pipe with a
Holding Tank or Lagoon 82
11.0 FRENCH DRAINS . . 84
11.1 Technology Description 84
11.2 Technology Applicability . . .- . . '.' . . 84
11.3 Technology Limitations . . . . 85
11.4 Cost Components % 85
11.4.1 Design Assumptions . . 85
11.4.2 Capital Components 85
11.4.3 Operation and Maintenance Components . "... 86
11.4.4 Cost Components Excluded 86
11.5 Cost Equations . .86
12.0 LAND APPLICATION . 88
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TABLE OF CONTENTS
(continued)
Page
12.1 Technology Description ...,.... 88
12.2 Technology Applicability v 89
12.3 Technology Limitations ...;..... 90
12.4 Liquid Sludge Land Application Cost Components-. 91
12.4.1 Design Assumptions . ....;.... 91
12.4.2 Capital Components 92
12.4.3 Operation and Maintenance Components '..'.. 92
12.4.4 Cost Components Excluded 1 93
12.5 Liquid Sludge Land Application Cost Equations 93 .
12.5.1Spfinkler System ...~ .- 93
12.5.2 Trucking System 94
12.6 Dewatered Sludge Land Application Cost Components 95
\
12.6.1 Design Assumptions 95
12.6.2 Capital Components 95
12.6.3 Operation and Maintenance Components . 96
12.6.4 Cost Components Excluded 96
12.7 Dewatered Sludge Land Application Cost Equations 96
v, ' -
13.0 NONHAZARDOUS WASTE LANDFILL 1 .' I . i . 98
13.1 Technology Description , .......>. .98
13.2 Technology Applicability and Limitations . ., 98
13.3 Cost Components 100
13.3.1 Design Assumptions ..'..; 100
13.3.2 Cost Components. '. . . 100
13.4 Total Annual Cost Equation ". 101
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14.0 HAZARDOUS WASTE LANDFILL . . . . 102
14.1 Technology*Description -. . . 102
14.2 Technology Applicability and Limitations . ; . 103
14.3 Cost Components . . .' . . ... ...... ^ ................ 104.
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TABLE OF CONTENTS
. (continued)
P_age
14.3.1 Design Assumptions ; 104
14.3.2 Cost Components 104
14.3.3 Cost Components Excluded 105
*
14.4 Total Annual Cost Equation 105
14.4.1 Hazardous Waste Disposal 105
14.4.2 Stabilization and Hazardous Waste Disposal 105
15.0 RADIOACTIVE WASTE DISPOSAL . . 106
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15.1 Sources of Radioactivity in Drinking Water . 106
15.2 Radium Removal . 107
15.3 Low-Level Radioactive Waste Disposal 108
. 15.4 Cost Information . '. . 110
16.0 REFERENCES . 110
LIST OF TABLES
Table 1 - Water System Categories ...,./. 1
Table 2 - Chemical Coagulation Sludge Volumes . . , . '. . 10
Table 3 - Lime Softening Sludge Volumes '. 12
Table 4 - Ion Exchange Brine Volume ..:... . . 13
Table 5 - Reverse Osmosis Brine Volumes : . . 14
Table 6 - Capital Cost Factors and Selected Unit Costs . 18
Table 7 - Operation and Maintenance Cost Factors and Unit Costs 20
Table 8 - Treatment System Sizing '. 24
Table 9 - Gravity Thickening 30
Table 10 - Chemical Precipitation ....'... : 37
Table 11 - Pressure Filter Presses 44
Table 12 - Sand Drying Beds ' ....;...: 51
fable 13 - Storage Lagoons - Lime Softening Sludge 58
Table 14 - Evaporation Ponds 65
Table 15 - POTW Discharge , : '... 71
Table 1.6 - Direct Discharge ...-..-. . . . . . 78
Table 17 - Liquid Sludge Land. Application .'. . . '. . 92
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TABLE OF CONTENTS
(continued)
LIST OF FIGURES
Figure 1 - Sludge/Slurry Producing Water. Treatment Processes
Figure 2 - Brine Producing Water Treatment Processes ....'.
Figure 3 - Brine Treatment arid Disposal Options >. ..
Figure 4 - Sludge/Slurry Treatment and Disposal Options ."...
Page
. 4
. 5
25
26
APPENDIX A - POTW Charges
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1.0 INTRODUCTION
1.1 BACKGROUND
' "
The Safe Drinking Water Act (SDWA) Amendments of 1986 require the United States
Environmental Protection Agency (EPA) to list the best available technologies (BAT) capable
of meeting maximum contaminant level regulations. BAT is developed to assist EPA in
setting drinking water standards, particularly for taking into consideration the capabilities of
\
various treatment technologies for removing contaminants from water, to assist water utilities
in selecting appropriate treatment methods to meet the regulations, and to identify treatment
technologies that are appropriate for small water treatment systems under Section 1415 of the
SDWA.
The Office of Ground Water and Drinking Water ,(OGWDW) must assess the waste treatment
and disposal practices likely to be used by the regulated community as part of its
responsibilities to determine the costs of the National Primary Drinking Water Regulations.
Special problems associated with small community water treatment byproducts management
are addressed in this document. A separate document addresses the byproduct management
methods for large water treatment systems. . . ,
1.2 PURPOSE AND SCOPE
The purpose of this document is to present methods to estimate water byproduct management
costs applicable to small water systems. Small water systems include systems in Categories 1
through 4 identified in Table 1. These systems are designed for populations ranging from 25
to 3,300 people and have design flow rates ranging from 0.024 to 0.65 million gallons per day
(MOD).
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TABLE 1
WATER SYSTEM CATEGORIES
Category
1
. 2
3
4'
5
6
7
8
' \ 9
10
11
12,
Population Range
25-100,
101-500
501-1,000
1,001-3,300,
3,301-10,000
10,001-25,000
25,001-50,000
50,001-75,000
75,001-100,000
100,001-500,000
500,001-1,000,000.
Greater than 1,000,000
Median
Population
57
225
V
750
1,910 .
5,500
15,500
35,500.
60,000
88,100.
175,000
730,000
1,550,000
Average
Flow
(MOD)
0.0056
0.024
,0.086 ,
' 0.23
0.7
2-1
5
8.8
13
27
120
270
Design Flow
(MGD)
0.024
0.087
0.27
0.65
1.8
. 4.8
11
18
26
51
210
430
Source: U;S. EPA, OGWDW.
This document contains technology descriptions and the estimated costs for the treatment and
disposal of water treatment byproducts from small water systems. Selected waste treatment
and disposal options are included in this document. These options are intended to provide a
general overview of the costs associated with the treatment and disposal of water treatment
plant byproducts. Cost equations in this document are for comparison purposes only. Site
i ' * ,
specific factors will cause individual cases to vary considerably from these estimates.
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1.3 WATER TREATMENT PROCESSES
Four primary water treatment processes that produce byproducts are considered in this
document: 1) coagulation and filtration, 2) lime softening, 3) ion exchange, and 4) reverse
osmosis. Although this cost analysis focuses on byproducts from these four water treatment
processes, the costs presented in this document are applicable to byproducts from other water
treatment processes that produce similar residuals. The byproducts result from the material in
the unprocessed water (i.e., suspended and dissolved materials) and/or from the chemicals
used to remove this material. Coagulation and filtration and lime softening generate
* " . - - - ^
byproducts.classified as sludges and slurries. Ion exchange and reverse osmosis generate
byproducts classified as brines. Figures 1 and 2 present simplified flow diagrams for these
four water treatment processes. A brief description of each of these water treatment
technologies is presented below.
Coagulation and Filtration
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Chemical coagulation and filtration, also referred to more generically as suspended solids
removal, are processes used to remove a variety of substances including participate matter that
causes turbidity, microorganisms, color, disinfection byproduct precursors, and some
inorganic contaminants. This type of treatment typically is used for surface water. The
-1
treatment process consists of three phases: 1) addition of a coagulant which is vigorously
mixed throughout the water being treated, 2) light agitation of the water for a period of time to
promote particle growth and agglomeration, and 3) settling and/or filtration of the flocculent.
The resultant waste byproduct is a sludge or slurry.
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Lime Softening
Lime softening, also referred to as precipitative softening, can remove a wide range of
contaminants including turbidity, microorganisms, calcium, magnesium, barium, radium,
cadmium, lead, zinc, chromium III, and arsenic V. Precipitation of these contaminants is
performed by the addition of lime or lime with soda ash. Lime softening is often followed by
i
a coagulation and sedimentation stage to improve removal of the paniculate matter. This
- treatment typically is used for ground water; however, in some regions of the country, river
water also may require softening; The resultant waste byproduct is a sludge or slurry
consisting of a high pH calcium hydroxide flpcculent.
Ion Exchange
Historically, ion exchange was used to remove hardness-causing cations, such as calcium and
magnesium; however, currently it also is used to remove radium, barium, iron, manganese,
\.
cadmium, lead, chromium III and VI, nitrates, uranium, selenium, and arsenic V. This
treatment typically works best on.ground waters, since surface waters frequently require
pretreatment to remove turbidity. Ion exchange is a separation process hi which dissolved ions
undergo a phase transfer from a solution to a solid-surface phase. The resultant waste
\.r
byproduct is a brine. j ,
Reverse Osmosis
' / *
Reverse osmosis is used to treat water to remove a wide variety of contaminants including ions
in brackish water, ions that cause hardness, uranium, radium, and most inorganics regulated
under the SDWA. Reverse osmosis is not used to remove mercury or arsenic IE. It is a
membrane-separation technique in which a semipermeable membrane allows water to permeate
through it while acting as a barrier to the passage of dissolved, colloidal, and paniculate
matter. The resultant waste byproduct is a brine.
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1.4 BYPRODUCTS GENERATED
The byproducts generated are classified as either sludges and slurries or brines. The sludges
and slurries are water-solid mixtures where the solids or particulates comprise at least 0.5
percent of the mixture and the solids are suspended rather than dissolved. Brines are solutions
with a dissolved salt concentration rather than an undissolved phase as with sludges and
slurries. Backwash water, whose composition depends on the water treatment technology
employed, is assumed to be routed into the byproducts stream. In general, the backwash
stream has a composition similar enough to the primary byproduct for this to be practical.
The backwash volume is included in the volumes considered for byproducts
treatment/disposal.
1.5 BYPRODUCTS MANAGEMENT OPTIONS OVERVIEW
r
.'
There are several management methods for water treatment byproducts. The management
method selected depends upon the water treatment practices and the byproduct characteristics.
Management methods should be thoroughly evaluated to minimize the possibility of generating
hazardous or low-level radioactive residuals. Hazardous and low-level radioactive wastes .
must be managed in accordance with existing regulations. Methods for management of the
byproducts produced from small system water treatment facilities include the following
options:
Chemical Precipitation;
Mechanical Dewatering;
Nonmechanical Dewatering;
- Evaporation Ponds;
POTW Discharge;
Direct Discharge;
- French Drain;
Land Application;
Nonhazardous Waste Landfill;
Hazardous Waste Landfill; and
Radioactive Waste Disposal.
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Management options applicable to sludges and slurries include 1) mechanical dewatering, 2)
nonmechanical dewatering, 3) land application, 4) hazardous waste landfill, and 5)
nonhazardous waste.landfill. Management options applicable to brines include 1) POTW
discharge, 2) chemical precipitation, 3) french drain, 4) direct discharge, arid 5) evaporation
ponds.
Radioactive wastes should be managed in accordance with EPA's guidance entitled "Suggested
Guidelines for the Disposal of Drinking Water Wastes Containing Naturally Occurring
Radionuclides." The guidelines were originally issued in 1990 and will be revised when the
Agency issues regulations relating to radionuclides.
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2.0 BYPRODUCT CHARACTERIZATION
2.1 INTRODUCTION
Water byproducts, or the waste streams generated during the treatment of water to obtain
drinking water, consist of sludges, slurries, and brines. For this study, these byproducts are
assumed to be generated from four water treatment technologies: chemical coagulation and
filtration, lime softening, ion exchange, and reverse osmosis. Although this cost analysis
focuses on byproduct volumes and characteristics generated by these four technologies, the
costs presented in this document are applicable to byproducts from other water treatment
processes that produce similar residuals.
In general, the volume of byproducts generated is dependent on the quality of feed water, the
efficiency of the treatment system, the water usage rate, the amount of chemicals used, and the
water treatment technology employed. The volume also can vary seasonally or monthly;
* t
variations are not unusual for different months of the year. To estimate the byproducts
generated on a national basis, assumptions regarding these parameters are made and described
in the following paragraphs which address each water treatment technology.
i . -
2.2 CHEMICAL COAGULATION AND FILTRATION
Chemical coagulation and filtration is frequently applied to surface waters to remove organic
matter and to pretreat hard-to-remove substances such as taste and odor compounds and color.
The most common chemical coagulant used is alum.
Based on actual facility data, alum sludge generation quantities range from 0.001 to 0.37
percent of the treated water flow rate with an average of 0.11 percent (Ref. 1). The alum
sludge volumes for the range of flow categories for small systems are summarized in Table 2.
The solids concentration of this sludge ranges from 0.5 to 3 percent.
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TABLE 2
CHEMICAL COAGULATION SLUDGE VOLUMES
Water Treatment Plant Flow
(gal/day)
5,600
24,000
87,000
270,000
' 650,000
Typical Volume Ranges
(gal/day)
0.06-21
0.25-90
1-300
3-1,000 :
7-2,400
Typcial Volumes
(gal/day)
10
30
100
300
700
From this analysis,' the volume of chemical coagulation sludge generated ranges from 0.06 to
2,400 gallons of sludge per day depending on the water treatment plant flow rate.
To estimate the amount of sludge produced in an alum coagulation plant for the removal of
turbidity, based on specific feed water characteristics, the following equation can be used (Ref
2). - .
S = 8.34 Q (0.44 Al + SS + A)
Where: S = sludge produced in pounds per day
Q = plant flow in million gallons per day
Al = Alum dose in milligrams per liter
SS = raw water suspended solids in milligrams per liter
A = additional chemicals added such as polymer, clay,
or activated carbon in milligrams per liter
Since most water treatment plants do not routinely measure suspended solids, turbidity is often
/
used to estimate suspended solids. The relationship between turbidity and suspended solids
can be represented by the following equation: '
s ,
SS = b Tu
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Where: SS = raw water suspended solids in milligrams per liter
b = factor determined based on characteristics of raw
water, typically 0.7 to 2.2
Tu = turbidity
This correlation should be determined for a specific water treatment plant over a period of
time since turbidity can vary seasonally for the same water supply.
The filter backwash volume from chemical coagulation and filtration depends upon the number
of filters and frequency and duration of each backwash event. The volume generated ranges
from 0.5 to 5 percent of the treated water. In general, small treatment plants will generate a
higher percentage of filter backwash than large treatment plants because they tend to operate
less efficiently. ' .
2.3 LIME SOFTENING
/
Lime softening is the precipitation of calcium, magnesium, and other cations from water using
lime and soda ash. Calcium and magnesium are the primary ions which contribute to water
hardness. For the purposes of this document, it is assumed that lime softening is used
specifically to.remove calcium carbonate and magnesium bicarbonate hardness. It is also
assumed that lime softening is performed only on ground water; however, hi some regions of
the country, river water also may require softening.
The quantity of lime softening sludge ranges from 0.4 to 1.5 percent of the treated water flow
rate, with an average of 1.2 percent. The lime sludge volumes for the range of flow
categories for small systems are summarized in Table 3. The initial solids concentration of
this sludge ranges from 2.4 to greater than 25 percent with the majority of facilities having a
solids concentration of 2.4 percent.
11
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TABLE 3
LIME SOFTENING SLUDGE VOLUMES
Water Treatment Plant Flow
(gal/day)
5,600
24,000
87,000
270,000
650,000
Typical Volume Ranges
(gal/day)
20-90
100-400
350-1,300
1,100-4,100
2,600-9,900
Typical Volumes
(gal/day)
70
300
1,100
3,300
7,900
The volume of sludge generated from lime treatment facilities ranges from 20 to 9,900 gallons
per day depending on the water treatment plant flow rate.
/'
The filter backwash volume from lime softening depends on the number of filters and
frequency and duration of each backwash event. The volume generated ranges from 0.5 to 5
percent of the treated water. In general, small treatment plants will generate a higher
percentage of filter backwash than large treatment plants because they tend to operate less
efficiently.
2.4 ION EXCHANGE
Ion exchange processes are used to soften water and remove impurities. Ion exchange systems
can be used to remove cations (e.g., calcium and magnesium) or anions (e:g., chloride).
Brines are produced from rinsing, regenerating, and backwashing the ion exchange unit. Of
these three byproducts streams, the regeneration stream contains the highest levels of total
dissolved solids (TDS) ranging from 10 to 300 times the levels found hi the feed water. The
range of the average TDS from ion exchange brines is 15,000 to 35,000 milligrams per liter
(mg/1) (Ref. 2). This high TDS content is the result of the salts removed from the exchange
12
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resin during regeneration as well as excess regeneration salts. By mixing the regeneration
stream with the rinse and backwash streams, dilution by approximately an order of magnitude
can be achieved.
The byproduct quantities (brines) from ion exchange range from 1.5 to 10 percent of the
treated water depending on the hardness of the feed water and the type of ion exchange unit
used. In general, for every kilogram of hardness removed, approximately 3 to 15 gallons of
brine are produced (Ref. 2) Operating data from six operating ion exchange water treatment
plants indicate that the volume of brine generated ranges from 17 to 83 gallons per 1000
gallons of water processed (Ref. 2). Brine volumes are calculated assuming that these brine
generation rates are applicable to small treatment systems; the low end of this range is used as
the typical volume of brine generated. The resultant brine generation rates are provided in
Table 4.
i
TABLE 4
ION EXCHANGE BRINE VOLUME
Water Treatment Plant Flow
(gal/day)
5,600
24,000
87,000
270,000
650,000
Typical Volume Range
(gal/day)
100-500
400-2,200
1,500-7,900
4,700-24,400
11,200-58,800
Typical Volumes
(gal/day)
100
400
1,500
4,700
11,200
The volume of brine produced from small ion exchange facilities -ranges from approximately
100 to 58,800 gallons per day depending on the water treatment plant flow rate, the quality of
the untreated water, and the type of ion exchange system used.
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2.5 REVERSE OSMOSIS .
Reverse osmosis processes use a semi-permeable membrane that allows water to pass through
it while restricting the passage of dissolved, colloidal, and paniculate matter. The byproducts
stream contains the salts and other materials rejected by the membrane.. The byproduct stream
has a high TDS concentration. Concentrations of specific contaminants in the byproducts
stream may range from 2 to 9 times the concentration in the feed water (Ref.3). For the small
facility sizes being considered in this analysis, the volume of reject water or brines produced
from backwashing the membrane are typically 25 to 50 percent of the feed flow with TDS
concentrations 3 to 4 times higher than the concentration of the feed water (Ref.3). The
percentage of reject water produced decreases as the size of the water systems increase due to
increased efficiencies. For the purposes of estimating brine generation from reverse osmosis
water treatment plants, the volume of reject water is assumed to range from 25 to 50 percent
of the feed water. The brine volumes are presented in Table 5.
TABLE 5
REVERSE OSMOSIS BRINE VOLUMES
Water Treatment Plant Flow
(gal/day)
5,600 .
24,000
87,000
270,000
650,000
Typical Volume Range
(gal/day)
.y
1,900-5,600
8,000-24,000
29,000-87,000
90,000-270,000
216,700-650,000
Typical Volume
(gal/day)
5,600
24,000
46,850
90,000
216,700
The volume of brine produced from a reverse osmosis facility ranges from 1,900 to 650,000
gallons per day depending on the water treatment plant flow rate, the initial water quality, and
the efficiency of the membrane.
14
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2.6 BYPRODUCT DENSITIES
The densities of the byproduct streams from the water treatment technologies considered in
this analysis are, in general, dependent on the solids concentration. In general, the brines
resulting from reverse osmosis and ion exchange, although high in total dissolved solids, have
a solids concentration of less than one percent. Therefore, the brine density is assumed to be
that of water or 62.43 pounds per cubic feet (lb/ft3).
The density of the sludges generated from lime softening and chemical coagulation are more
variable and are dependent primarily on the solids concentration or moisture content. The
sludge density is assumed to range from 64 to 74 lb/ft3 (Ref.4). If the solids content of a
specific byproducts stream is known, the sludge density can be calculated from the following
equation (Ref. 3):
Density = 100
percent solids + 100-percent solids
density solids density water
This equation is applicable for sludge with a solids concentration of less than 50 percent. A
typical value for the density of the solids in an alurn or iron sludge is 145 lb/ft3 (Ref.3).
Dewatered sludge densities also can be calculated using the equation provided as long as the
solids concentration remains below 50 percent. A typical density of a dewatered sludge is
assumed to be 100 lb/ft3 (Ref.3).
2.7 REFERENCES
1. Robertson, R.F. and Y.T. Lin. "Filter Washwater and Alum Sludge Disposal: A Case
Study." Proceedings AWWA Seminar on Water Treatment Waste Disposal Seminar.
(June 25, 1978), 4, 1-8.
2. American Water Works Association. Handbook: Water Treatment Plant Waste
Management. 1987
15
-------
3. American Water Works Association. Sh'b. Schlammr Slydge. KIWA Ltd., 1990.
4. American Water Works Association. Sludge: Handling and Disposal. Denver, CO:
American Water Works Association, 1989.
16
-------
-------
3.0 COST ASSUMPTIONS
3.1 INTRODUCTION
The costs included in this document are based on a variety of sources including computer cost
models, published cost information, and vendor quotes: All costs presented in this document
are in 1992 dollars. The cost equations presented in this cost document should be used for
relative comparisons and broad base estimation purposes only. Individual project costs have
been found.to be very different from those presented herein. This is primarily due to site-
specific factors such as physical and.chemical characteristics of the residuals, site constraints, .
operational costs and differing state and local regulatory requirements. More accurate site
specific cost estimates should be developed for facility planning and budgeting purposes.
\
3.2 CAPITAL COST ASSUMPTIONS
Table 6 presents cost factors and unit costs used to calculate the capital costs presented in this
document. The land, buildings, and piping components are discussed in detail below. Other
capital cost items (e.g., tanks, lagoons, pumps) were calculated individually.
Land .
<
Land prices vary substantially across the country. Land prices depend on the proximity to
metropolitan areas, state of land development (i.e., unproved or unimproved), current use, and
scarcity of land. A cost of $1,000 per acre is assumed for small water systems. This land
cost represents an average cost for rural, unimproved land. Costs for unimproved rural land
vary from approximately $150 per acre in states with large tracts of undeveloped land to
$2,200 per acre in states with small tracts of undeveloped land. Costs for suburban or
industrial unimproved land averages $10,000 per acre and ranges from approximately $4,000
per acre to $350,000 per acre depending on location.
1-7
-------
TABLE 6
CAPITAL COST FACTORS AND SELECTED UNIT COSTS
Component
Land
Buildings
Piping
Pipe Fittings
Electrical
Instrumentation
Engineering Fee
Contractor's Overhead and Profit
Factor/Unit Cost
$l,000/Acre
$33.00/Ft2
5% of Installed Equipment*
20% of Piping Costsf
1 % of Installed Equipment
1-2% of Installed Equipment
15% of Direct Capital
12% of Direct Capital
* Piping costs are calculated directly when piping is a significant cost (e.g., for direct
'discharge).
f Factor is used when piping costs are calculated directly
Costs for purchasing land are included in the capital cost equation for all treatment and
disposal processes that use surface impoundments and for french drains. For example, an
impoundment is used for storage prior to land application. The land costs are presented as a
separate cost in the capital cost equation to allow the user to delete the cost for land if no
purchase is required or to vary the cost of the land if the unit cost of land for a given area is
available. When the above criteria are met, a minimum land purchase of Vz acre is used in
developing land costs.
Land costs are not included for direct discharge and POTW discharge. It is assumed that the
water treatment authority is able to obtain an easement for placement of a sewer or discharge
line.
Buildings
Similar to land costs, building costs vary, substantially based on geographic location. The
building cost of $33.00 per square foot, listed in Table 6, is taken from 199% jVteans Building
Construction Cost Data. This cost is for a basic warehouse or storage building and includes
"\
electrical, foundations, heating, ventilation, air conditioning, and plumbing. It includes a 10
percent surcharge for structures of less than 25,000 square feet. This cost is the median cost
18
-------
for basic warehouse and storage buildings. The lower quartile cost is $21.30 per square foot
and the upper quartile cost is $45.65 per square foot. Different warehouse or building
configurations will change this unit cost.
Costs.for constructing buildings are included in the capital cost equation for equipment
intensive byproduct treatment technologies. For example, building costs are included in the
capital cost for chemical precipitation and mechanical dewatering. The building costs are
presented as a separate cost in the capital cost equation to allow the user to delete the cost for
land if construction of a building or addition to an existing building is unnecessary. .
Piping and Pipe Fittings
Piping costs are calculated in two separate manners depending on the magnitude of the piping
costs. For management systems in which the piping constitutes a significant portion of the
capital cost (e.g., direct discharge and POTW discharge), piping costs were calculated by
sizing individual pipe lengths and determining installation charges. For these management
systems, pipe fittings are assumed to be 20 percent of the installed piping costs. For
management systems where piping is not a significant cost (e.g., chemical precipitation and
mechanical dewatering), piping and pipe fittings are assumed to be 5 percent of the installed
equipment costs.
3.3 OPERATION AND MAINTENANCE ASSUMPTIONS
\
Table 7 presents cost factors and unit costs used to calculate the operation and maintenance
costs presented in this document. The labor rate is discussed below. ,
19
-------
TABLE 7
OPERATION AND MAINTENANCE
COST FACTORS AND UNIT COSTS
Component
Factor/Unit Cost
Labor
Insurance and General and Administrative
Expenses
Maintenance
Electricity
$14.50/Hour
2% of Direct Capital, Excluding Land
and Buildings
2-3% of Direct Capital, Excluding Land
and Buildings
$0.086/Kilowatt-Hour
Labor
The labor rate is based on a 10-region average for nonunion scale laborers. The hourly rate of
$14'.50 is based on an average salary of $8.65 per hour with a 12.2 percent fringe benefit and
a 50 percent labor overhead cost. Average salaries by region range from $7.25 per hour in the
south central to $10.17 in the western United States. Fringe rates range from approximately 8
to 15 percent depending on the region of the country.
Insurance and General and Administrative Expenses
A factor of two percent of the direct capital cost excluding land and buildings is used to
estimate insurance and general and administrative expenses. This cost is not included for
POTW discharge, direct discharge, trench drain, and lagoon-based technologies.
Maintenance
A factor of two to three percent of the direct capital cost excluding land and buildings is used
to estimate maintenance expenses., It is assumed that no maintenance is required over the 20-
year operating life for POTW discharge, direct discharge, and french drain systems.
20
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3.4 TOTAL ANNUAL COST ASSUMPTIONS
Total annual costs are equal to the sum of the operation and maintenance costs plus the
annualized capital costs. Annualized capital costs are calculated based on a 20-year operating
life and an interest rate of 10 percent. The capital recovery factor for a 20-year operating life
and 10 percent interest rate is 0.1175. Alternate capital recovery factors can be calculated
using the formula presented below.
Capital Recovery Factor = (1 + i)N (i)'
Where: i = interest rate
N = number of years
1
3.5 COST COMPONENTS EXCLUDED
The following cost components are not included in the cost estimates presented in this
document. Other excluded costs, specific to each management option, are highlighted under
their respective technology cost sections.
Sample Collection and Laboratory Analysis
Costs for sample collection and analysis to determine solids content, free liquids, toxicity
characteristics, and other parameters are not included in the costs presented in this document.
Sampling frequency is highly variable. Depending on the byproducts management method
selected, sampling requirements can be minimal or extensive.
Permits and Other Regulatory Requirements
*
Costs for permits and other regulatory requirements are not included in this analysis.
Requirements vary from state to state for a given management option. Permitting costs will
vary based on the size and complexity of a unit and the local governing jurisdiction.
, 21
-------
Management methods that may require permits include french drains, direct discharge, land
application, evaporation ponds, and storage lagoons. In addition, generators of hazardous
waste are required to comply with RCRA generator requirements (40 CFR Part 262).
Mechanical Backup
Costs for equipment backup, or redundancy, are not included in these cost estimates.
3.6 COST EQUATIONS
The cost equations for the capital components and for operation and maintenance were
developed by estimating the costs for different byproduct flow rates. Equipment sizes and
. ' i
retention times were selected based on published literature, vendor contacts, and best
engineering judgement. Capacities for major equipment components are presented in each cost
chapter. Each cost equation encompasses the range of expected byproduct flow rates unless a
specific technology is not applicable to the entire range. For example, French drains are
typically used for flow ratesi of less than 10,000 gallons per day. The cost equations only
include brine flow rates of less than 10,000 gallons per day even though the highest flow rate
expected is two orders of magnitude higher than 10,000 gallons per day.
The limits of .the cost equations presented for each byproduct management method may be
extended somewhat beyond the limits presented in this document. The upper or lower end for
some equations, however, may represent the largest or smallest practical units. Therefore, the
technology limitations and design assumptions should be carefully reviewed prior to extending
the limit of the equations. Best engineering judgement should be used when extending the
equations beyond their specified ranges.
The capital and operation and maintenance equations encompass the water byproduct volumes
generated by both the design flow rates and the average operating flow rates for Category 1-4
water treatment plants. The user may want to size the equipment (i.e., determine the capital
22
-------
cost) for the byproducts produced from the water treatment system design flow rate, while
calculating the operating cost using the average byproduct flow rate. Thus the equipment is
sized for peak flow periods, but the actual operating costs may be more closely estimated.
Typically, the design flow rate for the water treatment system may be two to three tunes the
average operating flow rate for the water treatment facility. When calculating the costs for
capital intensive management technologies such as chemical precipitation and mechanical
dewatering, the user may want to calculate both the capital and operation and maintenance
costs using the average operating flow rate. Table 8 indicates whether the water treatment
design flow rate or average flow rate should be used to calculate the capital and operation and
maintenance costs. The user of this document may always use the design flow rate to calculate
costs, but this may result in substantial over estimation of the cost to treat water byproducts
generated by an actual facility.
3.7 CALCULATING BYPRODUCT MANAGEMENT COSTS
Byproduct management costs, are calculated using the cost equations presented in the following
chapters. Known byproduct flow rates from an operating facility may be used or approximate
byproduct volumes can be estimated using the information presented in Sections 2.3 through
2.6. Figures 3 and 4 present management options applicable to brines and sludges/slurries,
respectively. These figures present complete management trains. That is, they depict
byproduct management methods, resulting residuals, and management options for those
residuals. Individual cost chapters present residual factors to use to determine residual
volumes that require further treatment or disposal. The overall byproduct management costs
are determined by summing the capital and operation and maintenance costs from the treatment
and disposal of all byproducts and residuals.
23
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TABLES
TREATMENT SYSTEM SIZING
Technology
Gravity Thickening
Chemical Precipitation
Mechanical Dewatering
Non-mechanical Dewatering
Evaporation Ponds
POTW Discharge
Direct Discharge
French Drain
Land Application
Non-Hazardous Waste
Disposal
Hazardous Waste Disposal
Radioactive Waste Disposal
Capital Cost
Average
Average
Average
Design
Design
Design
Design
Design
Design
NA
NA .
NA
Operation & Maintenance
Cost
Average
Average
Average
Average
.Average
Average
Average
' Average
Average
NA
NA -
NA
24
-------
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-------
4.0 GRAVITY THICKENING
4.1 TECHNOLOGY DESCRIPTION
In this report, gravity thickening is a treatment technology considered for filter backwash and
sludges. Gravity thickening serves to increase the solids concentration of the filter backwash
and sludge streams so they can be treated by one of the dewatering methods addressed in the
following sections.
Filter backwash byproducts are high volume, low solids slurries generated during the cleaning
of water treatment plant filters. The volume of backwash waters generated varies for
individual treatment plants and depends upon the number of filters and the frequency and
duration of each backwash event. The total backwash volume is comprised of upflow
backwash, downflow regeneration, and downflow rinse. In general, this volume ranges from
0.5 to 5.0 percent of the treated water with the larger treatment plants producing less .
backwash per million gallons of treated water than smaller treatment plants due to increased
plant efficiency. ,
Where practical, backwash waters are recycled to the head of the treatment works for
management. Recycling serves two purposes: it reduces the quantity of treated water lost to
backwashing and it reduces the total volume of sludge generated. In cases, where backwash
recycling is not possible, discharge to a surface water, publicly-owned treatment works
(POTW), or treatment by nonmechanical and mechanical dewatering are other treatment and
disposal options.
\
In cases where backwash byproducts cannot be recirculated to the head of the plant nor
discharged to a surface water or POTW, the backwash waters must be disposed as a water
treatment slurry. Backwash waters are chemically similar to sludges produced by chemical
coagulation, but are more dilute. Backwash waters have an average solids concentration of
28
-------
0.08 percent, where chemical coagulation (alum) sludge have.a solids concentration ranging
from 0.5 to 2.0 percent.
Backwash water and sludges are gravity fed to a tank where gravity thickening is performed.
Gravity thickening occurs by allowing suspended solids to settle naturally. The sludge
discharged from the tank is routed for further treatment and the decant is either direct
\
discharged or recycled to the head of the treatment plant.
j
4.2 TECHNOLOGY APPLICABILITY AND LIMITATIONS
For this report, gravity thickening is applicable to the filter backwash streams and sludges
from chemical coagulation or lime softening byproducts streams. Because of the high volumes
and low solids concentrations characteristic of these byproduct waste streams, pretreatment is
necessary before the byproducts can be dewatered by the methods discussed in the remainder
of this report. Pretreatment also is necessary to equalize the flow rates.
4.3 COST COMPONENTS
s '
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
4.3.1 Design Assumptions
\
Gravity thickening is used to pretreat filter backwash and sludges from chemical
coagulation and lime softening.
The filter backwash and sludge flow by gravity from the treatment plant to the
settling tank.
Each treatment facility has 1 or 2 filters. Each filter is backwashed twice a
week with a backwash volume ranging from 490 to 24,200 gallons per event.
These backwash volumes are generated in 20 minutes.
The total backwash volume is either 2 or 2.5 percent of treated water.
29 -
-------
The backwash and sludge is allowed to settle in a tank for 31/2 days.
The volume of backwash and sludge is reduced by 90 percent.
V,
The thickened sludges are discharged to another treatment for further
dewatering. " ,
4.3.2 Capital Components -
i
The capital components for each filter backwash system consist of the following items:
Holding tank;
Piping and fittings;
Pump;
Trenching;
Electrical; and
Instrumentation.
Table 9 indicates the number of filters, the filter backwash volume, and backwash settling tank
capacities used to develop the capital cost equation for filter backwash.
TABLE 9
FILTER BACKWASH
Number of
Filters
1
1
1
1
2
Filter Backwash
Volume
(gal/event)
490
2,170
7,810
24,220
23,210
Number
of
Tanks
1 .
1
1
1
1
Backwash Settling
Tank Capacity
(gal)
500
2,500
10,000
30,000
50,000
30
-------
4.3.3 Operation and Maintenance Components
The operation and'maintenance components for each gravity thickening system include the
following items:
Electricity;
Labor;
Maintenance labor and materials; and
Insurance and general and administration.
4.3.4 Cost Components Excluded
The following cost components are not included hi the cost equations for gravity thickening
systems: . '
Supernatant disposal, if the supernatant cannot be pumped to the head of the
treatment plant; and
Thickened sludge disposal.
f \
Costs for supernatant disposal, if the supernatant cannot be pumped to the head of the
treatment plant, and treatment of the thickened sludge can be determined using other sections
of this document.
4.4 GRAVITY THICKENING COST EQUATIONS
* ' i
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for five different filterbackwash and sludge flow'rates. The filter
backwash and sludge flow rate (X) used in the equations below is the average daily volume
generated (e.g. 2.5 percent of the daily treated water flow rate). The capital cost equation
calculates the total capital cost (i.e., installed capital plus indirect capital costs). The total
annual cost is calculated based on the capital and operation and maintenance costs obtained
using the equations presented below.
31
-------
Capital Costs
Y = 1,500 + 0.01 X
Where: Y = $
X = gallons of filter backwash/sludge per day
Range: 5,600 gpd <; X <; 87,000 gpd
Y = 61.7 X050-6,200
Where: Y = $
X = gallons of filter backwash/sludge per day
Range: 87,000 gpd < X <; 650,000 gpd
Operation and Maintenance
Y = 300 + 3.82 x 103 X
Where: Y = $/year
X = gallons of filter backwash/sludge per day
Range: . 5,600 gpd s X <; 87,000 gpd
Y = 3.60 X050-400
Where: Y = $/year
X = gallons of filter backwash/sludge per day
Range: 87,000 gpd < X <; 650,000 gpd
32
-------
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
33
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5.0 CHEMICAL PRECIPITATION
5.1 TECHNOLOGY DESCRIPTION
s
Chemical precipitation is applicable to aqueous byproduct streams such as ion exchange
backwash and reverse osmosis brines. Chemical precipitation is frequently used to remove
dissolved metals from aqueous solutions. It can be used to remove metal ions such as
aluminum, antimony, arsenic, cadmium, chromium, copper, iron, lead, mercury, selenium,
silver,' thallium, and zinc. Hydroxide precipitation is the most widely used technology for
removing trace metals from wastewaters. Lime, quicklime, soda ash, or caustic soda are
commonly used as sources of hydroxide ions. Under suitable conditions, metals form
insoluble metal hydroxides which can be separated from solution by clarification and filtration.
Sulfide precipitation and ferrous salt precipitation also can be used depending on the metals
present in solution.
The precipitation process involves adding a precipitant, such as hydroxide ions, to ion
exchange or reverse osmosis brines in a stirred reactor vessel. The dissolved metals are
converted to an insoluble forni by a chemical reaction between the soluble metal ions and the
precipitant. The resultant suspended solids are separated from the aqueous phase in a clarifier.
Flocculation with or without a chemical coagulant or settling aid may be used to enhance the
removal of suspended solids. The supernatant from the clarifier is either discharged to the
sanitary sewer, to surface water or to the head of the treatment plant depending on the pH.
Prior to disposal, the clarifier sludge may require additional dewatering by mechanical or
nonmechanical means.
34
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5.2 TECHNOLOGY APPLICABILITY
; ,
Chemical precipitation is used primarily for treatment of reverse osmosis and cation exchange
waste brines. Chemical precipitation is used to remove the high levels of dissolved solids
found in these waste streams where less expensive treatment and disposal options are not
available. While technically feasible, chemical precipitation as a method to treat ion exchange
and reverse osmosis brines is an expensive waste treatment/disposal option relative to options
such as evaporation ponds, sanitary sewer discharge, french drain, and direct discharge.
Chemical precipitation is economically more feasible for large systems treating more than 1
million gallons of water byproducts per day. If chemical precipitation is the only method
available for ion exchange and reverse osmosis byproduct treatment, then ion exchange or
reverse osmosis may not be economically feasible water treatment options for small facilities.
, r
5.3 TECHNOLOGY LIMITATIONS
Anion exchange wastes cannot be treated by lime precipitation because sodium, chloride, and
sulfate dissolved ions are not readily precipitated by lime. In addition, the effluent from the
chemical precipitation process may still pose a disposal concern due to elevated levels of
dissolved solids such as sodium, chloride, and sulfate remaining in the effluent.
As mentioned above, chemical precipitation may be a relatively expensive treatment option
compared with french drain disposal, direct discharge, sanitary sewer discharge, and
evaporation ponds. Chemical precipitation has higher capital costs and higher labor costs than
many other byproduct treatment and disposal options. The higher labor costs are associated
with the oversight necessary for proper operation of the system.
uiL.
35
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5.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
5.4.1 Design Assumptions
The chemical precipitation system consists of mixing and holding tanks for the
. lime solution, a precipitation tank, a clarifier, agitators, and pumps.
The precipitation tank has a Vi-hour retention time and a 5 percent overdesign.
The clarifier (settling tank) has a 1- to 2-hour retention time.
Waste brines flow to the treatment system under pressure from the ion exchange
or reverse osmosis system.
The chemical precipitation equipment is located hi the water treatment building.
\
Sludge from the clarifier may require additional dewatering prior to disposal.
The sludge volumes generated by chemical precipitation are 5 and 2 percent of
the influent volumes for reverse osmosis and ion exchange brines, respectively.
5.4.2 Capital Components
The capital components for each chemical precipitation system consist of the following items:
Carbon steel mixing tank;
Carbon steel precipitation tank;
Clarifier/settling tank;
Agitators;
Sludge pumps;
Building;
Piping;
Electrical;vand
Instrumentation. .
36
-------
Table 10 indicates the brine volumes, tank capacities, and clarifier capacities used to develop
the capital cost equation for chemical precipitation.
TABLE 10
CHEMICAL PRECIPITATION
Byproduct
Flow Rate
(gal/day)
3,930
12,200
29,300
67,500
162,500
274,000
350,000
500,000
1,000,000
Precipitation
Tank Size
(gallons)
200
400
650
2,000
5,000
6,000
8,000
12,000
23,000
Mix Tank
Capacity
(gallons)
30
40
50
75
100
-"200
300
600
1,200
Clarifier
Capacity
(gallons)
800
1,600
2,500
8^000
20,000
24,000
30,000
40,000
50,000
5.4.3 Operation and Maintenance Components
The operation and maintenance components for each chemical precipitation system include the
following items:
Lime;
Electricity;
Labor;
Maintenance labor and materials;
Insurance and General and Administration; and
Water.
37
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5.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for chemical
precipitation systems since they are accounted for elsewhere hi the document:
Sludge dewatering (if needed for the selected disposal option);
Sludge disposal; and
Clarifier overflow disposal, if the overflow cannot be pumped to the head of the
treatment works.
Costs for sludge dewatering and sludge disposal techniques are included in other sections of
this document. Costs for clarifier overflow disposal, if the overflow cannot be pumped to the
head of the treatment works, can be determined using other sections of this document.
5.5 COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for seven different brine flow rates, the capital cost equation
calculates the total capital cost (i.e., installed capital plus indirect capital costs). Equipment
costs and building costs are separate components in the capital cost equation to enable die user
to exclude the cost for a building addition if it is not necessary. The total annual cost is
calculated based on the capital and operation and maintenance costs obtained using the
equations presented below.
Capital Costs
Y = [1,500 X °-36] + [4,900 + 135.5 X °-50]
Y = [Equipment Cost] + [Building Cost]
Where: Y - $
X = gallons of brine per day
Range: 3,000 gpd <. X <. 162,500 gpd
38
-------
Y = [1,500 X °36] + [253 X 05° - 39,300]
Y = [Equipment Cost] + [Building Cost]
Where: Y = $
X = gallons of brine per day
Range: 162,500 gpd < X * 1,000,000 gpd
Operation and Maintenance
Y = 366 X OM .
. Where: Y = $/year
X = gallons of brine per day
Range: 3,000 gpd * X * = 162,500 gpd
Y = 19,900 + 0.15 X
Where: Y = $/year - -
X = gallons of brine per day
Range: 162,500< Xi 1,000,000
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
39
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6.0 MECHANICAL DEWATERING
Mechanical dewatering processes include centrifuges, vacuum-assisted dewatering beds, belt
filter presses, and plate and frame filter presses. These processes have relatively high capital
and operation and maintenance costs compared to similarly sized nonmechanical processes.
Mechanical dewatering is not applicable to very small water plants due to the high capital costs
associated with these technologies and limited equipment sizes available. Though this
mechanical dewatering is more applicable to larger water plants, it is included here since
equipment is available for byproduct flow rates addressed in this document. Pressure filter
press technology, applicability, limitations, and costs are presented in this section.
r
6.1 TECHNOLOGY DESCRIPTION
A pressure filter, or plate and frame, press is a mechanical sludge dewatering method using a
positive pressure differential to separate free liquid from the sludge. Pressure filter presses
operate as batch processes. The press consists of adjacent plates that form a leak-proof seal
when electrically or hydraulically brought together. A positive displacement pump moves
sludge into chambers between the two plates. Initially the pump supplies a high volume of
sludge to the chamber at a low pressure. As the chamber fills, the pump creates positive
pressure on the sludge which forces liquid from the sludge. The pressure increases until the
desired solids concentration is achieved. After pumping ceases, the plates are separated and
the sludge cake is dropped into a container or onto a conveyor.
Pressure filter presses consist of multiple filter plates on metal frames. The capacity of a press
depends on the number and size of the plates and on the depth of the chamber between the
plates. Plates are available in a variety of sizes, shapes and materials. The choice of filter
media adds additional variation to the performance of an individual press. Filter media
40
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varies in its particle retaining size, permeability, durability, and its ease of cake release.
Sludge type and the initial solid's concentration of a sludge affect the filter media choice.
6.2 TECHNOLOGY APPLICABILITY
With proper sludge conditioning, pressure filter presses can effectively dewater both lime and
alum sludges. Lime sludges attain final solid concentrations of 40 to 70 percent while alum
sludges attain 35 to 50 percent final solid's concentrations. Dewatering with a filter press is a
batch process; each batch remains under pressure until the desired solids concentration is ..
achieved. This produces a consistent product. Filter presses produce a filtrate that has a
lower suspended solids concentration than filtrates from other mechanical dewatering methods.
Pressure filter presses have been used in water treatment and industrial processes for many
years. Use of pressure filter presses hi the water treatment industry has been increasing hi the
last several years. They are especially applicable for facilities that want to achieve a high
sludge solids content. The high solid's content achieved by pressure filter presses makes this a
suitable technique to dewater sludges before landfill. ;
Plate and frame filter presses have low land requirements, high capital costs, and are labor
intensive. They typically have higher capital and operating costs than comparable :.
nonmechanical dewatering alternatives. The high labor and capital requirements make them
more applicable to larger water systems. , .
6.3 TECHNOLOGY LIMITATIONS
Available, equipment sizes and equipment costs limit the applicability of this technology for
small water systems. Sludge flow rates less than 100 gallons per day are not applicable to
filter press dewatering. Even at 100 gallons per day, the filter press equipment is oversized.
41
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Although the suspended solid's concentration of the filtrate is low, filtrate disposal may be a
problem. Proper preconditioning of alum sludges before filter press dewatering normally
requires the addition of lime. Lime is used to lower the alum sludge's resistance to filtration.
A lime mixture is added to the alum sludge until a pH of approximately 11 is achieved. The
lime conditioning not only increases the total sludge volume (by as much as 20 to 30 percent
by weight), but also increases the pH of the resulting filtrate. The final filtrate pH may be too
high for sanitary sewer disposal or for recirculation to the head of ithe treatment plant.
Pumps that deliver sludge to the filter press must be capable of operating under a variety of
conditions. During initial pumping, sludge flow rates are high and pressures are low. Toward
the end of the cycle, the sludge flow rate is almost zero while pressures range from 100 to 200
psi. A positive displacement pump such as a progressive cavity pump must be used to achieve
required flow rates and pressures. A second alternative is to use two pumps: one to deliver
high flow rates at low pressure and a second to deliver high pressure and low flow rates.
Filter media must be cleaned every eight to ten cycles to ensure proper operation. Filter
cleaning is a time-consuming process requiring an acid wash to dissolve built up calcium
carbonate from press plates. The acid wash creates disposal problems due to its low pH.
Precoating the press reduces blinding and required frequency of cleaning, but adds to
operation and maintenance costs and potentially adds trace metals to the filtrate.
As with all mechanical dewatering methods, proper preconditioning of alum sludges is
essential to ensure efficient sludge dewatering. Sufficient quantities of lime must be added and
a 20- to 30- minute contact tune is required to develop the necessary dewatering qualities.
42
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6.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
6.4.1 Design Assumptions
Pressure filter presses are effective for sludge flow rates greater than 100
gallons per day.
Stainless steel filter presses with paper filter media are used for flow rates less
than 500 gallons per day.
Sludge flows by gravity to a polymer feed system.
The polymer feed system consists of a polymer storage tank, a polymer pump, a
polymer/sludge contact tank and a 20- to 30-minute holding tank.
'." ^ - '
A positive displacement pump delivers sludge to the filter press.
The filter press operates on a batch basis.
Filtrate collects hi a filtrate holding tank before being pumped to the head of the
treatment plant. .
Filter cake collects in a small, wheeled container, which is emptied into a larger
solid's bin as necessary.
Accumulated solids require disposal on a periodic basis.
The dewatered sludge volume is 0.03 and 8 percent of the initial volume for
lime and alum sludges, respectively.
6.4.2 Capita! Components
The capital components for each pressure filter press system consist of the following items:
Pressure filter press;
43
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Polymer feed system; . ., ..... .
Positive displacement pump;
Steel filtrate tank and pump;
Filter cake storage bin;
Building;
Piping;
Electrical; and
Instrumentation.
Table 11 shows the sludge volumes, settling tank/gravity thickener capacities, and filter press
capacities used to develop the capital cost equation for pressure filter presses.
TABLE 11
PRESSURE FILTER PRESSES
Sludge Flow Rate
(gal/day)
100
500
2,000
5,000
10,000
Filter Press Capacity
(cu. ft.)
0.5
2.0
10
24
24
6.4.3 Operation and Maintenance Components
The operation and maintenance components for each pressure filter press system include the
following items:
Electricity;
Polymer;
Labor;
Maintenance labor and materials; and
Insurance and general and administration.
44
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6.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for pressure filter press
systems:
Dewatered sludge disposal; and
Filtrate disposal, if the filtrate cannot be pumped to the head of the treatment
plant.
Costs for sludge disposal techniques are included in other sections of this document. Costs for
filtrate disposal, if the overflow cannot be pumped to the head of the treatment works, can be
determined using other sections of this document.
6.5 COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for five different sludge flow rates. The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). Equipment costs and
building costs are separate components in the capital cost equation to enable the user to
exclude the cost for a building addition if it is not necessary. The total annual cost is
calculated based on the capital and operation and maintenance costs obtained using the
>
equations presented below.
Capital Cost
Y - [11,500 + 1,155 X 05fr] + [3,500 + 143 X °-50]
Y = [Equipment Cost] + [Building Cost]
Where: Y = $
X = gallons of sludge per day
Range: 100 gpd <. X < 2,000 gpd
45
.
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Y = [11,500 + 1,155 X050] + [10,000]
Y = [Equipment Cost] + [Building Cost]
Where: . Y = $
X = gallons of sludge per day
Range: 2,000 gpd <: X <. 10,000 gpd
Operation and Maintenance '
Y = 578 X °50 - 400
Where: Y = $/year
X = gallons of sludge per day
. Range: 100 gpd z X < 10,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
46
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7.0 NONMECHANICAL DEWATERING r
Nonmechanical dewatering of sludges and slurries is performed in sand drying beds, storage
lagoons, and permanent lagoons. Nonmechanical dewatering processes are characterized by
their simplicity to operate and maintain. In sand drying beds and storage lagoons, dewatered
sludge is removed for disposal via land application or in a landfill. A permanent lagoon
dewaters the sludge and is the final disposal site for the sludge. Costs were developed for two
nonmechanical dewatering processes: sand drying beds and dewatering lagoons.
7.1 SAND DRYING BED DESCRIPTION
A sand drying bed is a nonmechanical means of dewatering sludges that utilizes drainage,
decanting, and evaporation. The technology involves spreading an even layer of thickened
sludge (solid concentrations of 1 to 4 percent for coagulant sludges and 2 to 6 percent for
softening sludges) over a draining sand bed. Free water in the sludge gravity drains through .
the sand to the underdrains or forms a supernatant layer that is decanted. Most gravity and
decant drainage occurs in the first few days after application. After this time, evaporation is
the primary dewatering process and the sludge remains on the drying bed until the desired
solids concentration is achieved. The depth of initial sludge application and the time required
for the sludge to dry on the sand bed are functions of several variables that need to be
determined individually for each treatment unit.
Drying beds are frequently constructed of concrete walls and floor with slotted pipe
underdrains buried beneath 18 to 24 inches of graded sand and gravel. Sludge from a
thickener is batch applied to the sand through one or several inlet structures. Free water
drains from the sludge through the sand bed to the underdrains. As they accumulate,
supernatant and rain water are drawn off by a variable height outlet structure. After drying,
sludge cake is removed manually by shovel and wheel barrow or mechanically with a small
47
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front end loader or tractor.
The method of sludge removal and the requirements at the ultimate disposal site determine the
desired sludge cake solid's concentration. Manual sludge removal, using a shovel and
wheelbarrow, requires solids' concentration of approximately 25 percent to ensure proper
sludge handling. Mechanically removing sludge by a vacuum truck or a front end loader
requires solids' concentrations in the range of 15 to 25 percent. Many landfills require sludge
cakes to have a minimum of 20 percent dry solids to meet acceptance criteria.
Sludge removal and disposal costs are a large percentage of the total operation and
maintenance costs for drying beds. Disposal costs of the solids are not included hi this
section, but can be determined by using the information presented hi other sections of this
document. Sludge removal costs are directly related to the number of sludge applications per
drying bed per year. Less frequent, thicker, sludge applications result hi a thicker sludge cake
that has lower unit costs for removal but may require more drying bed area. Individual
treatment plants must determine then: most cost effective drying tunes and disposal
frequencies. : . .
7.2 TECHNOLOGY APPLICABILITY
Sand drying beds effectively dewater lime and alum sludges to solids concentrations of 50
percent and 20 to 25 percent, respectively. At these solid's concentrations, both sludges are
suitable for landfilling or land application. Lime sludges have a smaller percentage of
chemically-bound water and dewater more quickly than coagulant sludges.
7.3 TECHNOLOGY LIMITATIONS
For alum sludge, which contains as much as 40 percent bound water, chemical conditioning by
polymers is frequently necessary to aid in the rapid release of water from the sludges.
48
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Chemical conditioning causes the sludge to set quickly. Once the polymer is incorporated into
the sludge, rapid application of a uniform depth of sludge is necessary for effective dewatering
and uniform drying. Several sludge application points in a drying bed or smaller bed sizes
may be necessary to ensure even application and drying of alum sludges. Consequently, due
to the increased labor and operating requirements associated with alum sludges, it is unlikely
that sand drying beds would be used for treating these sludges.
Seasonal weather conditions affect the tune sludge must remain on the drying beds. Treatment
plants located in northern or seasonally wet areas, must prepare for longer bed drying times in
cold or damp weather. Enclosing the drying beds reduces the variation in drying times by
shielding the sludge cake from rain and snow and increasing the ambient temperature around
the beds. Other options are to lagoon sludge during bad weather for application at a later date
or to build extra beds.
Drying beds are not effective for sludges with very low suspended solid's concentrations or
sludges with high percentages of dissolved solids. Low solids' sludges (less than 1 percent
solids) will move through and blind sand beds, reducing the beds' effectiveness. These
sludges must be thickened before drying bed application. High dissolved solid sludges, such
as the waste brines generated by reverse osmosis, are not effectively captured by drying beds
because the dissolved solids flow through sand beds into the underdrains.
7.4 SAND DRYING BED COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
7.4.1 Design Assumptions
Sand drying beds are used to dewater lime or non-alum sludges.
49
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Sludges flow to the lagoons or tanks via 500 feet of 2- to 6-inch diameter PVC
piping buried 4 feet below the ground surface.
The tanks or lagoons are sized to hold 21 or 42 days of volume. Typically 15
or 30 days of volume are necessary; however, the additional lagoon capacity is
provided for slower drying conditions.
Sludge is concentrated to 3 percent solids by weight in a lagoon or tank through
decanting and evaporation; the sludge volume is reduced by 67 percent.
The lagoons are constructed with a synthetic membrane liner and a geotextile
support fabric.
The lagoon bottom slopes to a sump.
No polymers are added to the sludge.
An 18-inch layer of sludge containing 3 percent solids is applied 6 to 12 times
per year to each sand bed.
The sludge pump and the drying bed piping are sized to deliver sludge to the
drying bed from the lagoon in one to two hours. Drying beds are located 100
feet from the lagoon.
Drying beds are sized to hold 33 percent of the initial sludge volume applied to
the bed in an 18-inch layer. Increased sizing is used to offset slower drying
tunes in bad weather.
Underdrains consisting of 2- to 6-inch diameter PVC piping collect filtrate.
Drying beds are constructed of reinforced concrete with a 6-ihch bottom slab
and 8-inch walls. The bed contains 18 inches of sand. The underdrain piping
rests in 6 inches of gravel underneath the sand.
The final solid's concentration is 20 percent by weight. Five percent of the
initial sludge volume (0.7 cubic feet of solids per 100 gallons of initial sludge
volume) requires final disposal.
uiiuai aiuugc vuiumc \\j. i ^UUIL.
volume) requires final disposal.
The sludge cake is removed from beds either removed manually or by using a
small front-end loader depending on the total surface area of the beds.
50
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7.4.2 Capital Components- .
The capital components for each sand drying bed system consist of the following items:
Dewatering tank or lagoon;
Piping and fittings;
Pumps;
Trenching;
One, two, or four sand drying beds;
Land clearing;
Electrical; and
Instrumentation.
Table 12 shows the sludge volumes, number of beds, and the total required surface area used
to develop the capital cost equation for sand drying beds.
TABLE 12
SAND DRYING BEDS
Sludge Volume
(gal/day)
20
100
500
- 2,000
5,000
10,000
Number of
Beds
1
2
2
2
4
4
Total Surface Area
(ft2)
25
150
750
2,500
3,200
7,000
7.4.3 Operation and Maintenance Components
The operation and maintenance components, for each sand drying bed system include the
following items:
51
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Electricity; .- .. , .
Sand replacement;
Labor;
Maintenance labor and materials; and
Drying bed cleaning.
7.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for sand drying bed
systems:
Drying bed enclosures;
Polymers and polymer feed system;
Dewatered sludge disposal; and
Supernatant disposal, if the supernatant cannot be pumped to the head of the
treatment plant.
Costs for sludge disposal techniques are included in other sections of this document. Costs for
supernatant disposal, if the supernatant cannot be pumped to the head of the treatment plant,
can be determined using other sections of this document.
7.5 SAND DRYING BED COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for six different sludge flow rates. The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). Equipment costs and
land costs are separate components in the capital cost equation to enable the user to exclude the
cost for purchasing land if it is not necessary. The total annual cost is calculated from the
capital and operation and maintenance costs obtained using the equations presented below.
Capital Costs
Y = [8,670 X °-25] + [0.5 X]
Y = [Equipment Cost] + [Land Cost]
52
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Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per acre (e.g., $l,000/acre)
Range: 20 gpd'<. X <: 1,000 gpd
Y = [1,936 X 05° -18,900] + [(9.69 x 10'2 + 1.89 x 1Q-4 X) Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per acre (e.g., $l,000/acre)
Note: For systems less than 2,000 gallons of sludge per
day, 1/2 acre of land is required.
Range: 1,000 gpd < X * 10,000 gpd
Operation and Maintenance
Y = 3,000 + 64.5 X 05°
Where: Y = $/year
X = gallons of sludge per day
Range: 20 gpd ^ X ^ 1,000 gpd
Y= 190 X050-1,600
Where: Y = $/year
X = gallons of sludge per day
Range: 1,000 gpd < X <. 10,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
53
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-------
Where: Y = $/year
CAP = capital cost
<^/vr = capiiai cosi
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
7.6 STORAGE LAGOON DESCRIPTION
Storage lagoons, although land intensive, have historically been the most common and the least
expensive method to thicken or dewater water treatment sludge. The lagoons are lined ponds
designed to collect and dewater sludge for a predetermined period of time. Dewatering of the
sludge occurs by decanting the supernatant and by evaporation. Additional dewatering can
also be achieved if the lagoons have a sand bottom. Storage lagoons are sized according to the
sludge volumes generated and storage time required for an individual treatment facility. When
a storage lagoon has reached its designed capacity, the remaining solids are typically removed
from the lagoon using a front-end loader and hauled off site for final disposal. Some treatment
works use permanent lagoons as longrterm disposal sites for sludges. As one lagoon fills,
another one is excavated.
^
Lagoons are usually earthen basins with gradual side slopes. Sizes range from less than one to
15 acres and from four to 20 feet deep. Clay or synthetic liners cover the bottom and
sidewalls to prevent ground water infiltration of sludge leachate. Sludge flows from the
treatment plant by gravity or is pumped to the lagoon through an underground pipe. The
lagoon inlet structure is designed to reduce turbulence in the lagoon caused by the incoming
sludge. The outlet structure usually provides for decanting of the supernatant at various draw-
off depths.
If the water byproduct residuals managed in the lagoons are determined to be hazardous waste,
these lagoons are subject to compliance with hazardous waste regulations for surface
impoundments. These regulations specify that the impoundments must be triple-lined with a
54
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synthetic flexible membrane liner and a composite double liner. Although there are no federal
requirements specifying the design for lagoons containing nonhazardous waste at this time,
regulations regarding nonhazardous waste in lagoons may be enacted in the future. Therefore,
good engineering practice suggests that at a minimum a synthetic liner should be included in
the design of the lagoon.
7.7 TECHNOLOGY APPLICABILITY
Storage lagoons are primarily used for the dewatering of lime softening sludge, although
coagulant (alum) sludge also can be dewatered in certain situations. Final solids'
concentrations reported for lime and alum sludges after lagooning are 20 to 60 percent and
seven to 15 percent, respectively. The higher solid concentrations (greater than 50 percent)
are achieved through decanting of the supernatant layer and allowing the sludge to air dry.
Lagoons can operate under a variety of sludge flows and solids concentrations. Lagoons with
low-turbulence inlet structures and outlet structures designed to minimize suspended solids
carryover can accept backwash waters directly from the filters. This eliminates the need for.
backwash holding tanks and sludge thickeners. Lagoons can withstand large variances in
sludge quality and do not require chemical conditioning of alum sludges.
Lagoons in areas with beneficial climates can achieve greater sludge dewatering. In areas with
hot, dry climates, storage lagoons function as evaporation ponds and can dewater both alum
and lime sludges to solid's concentrations suitable for land filling. In northern climates,
natural winter freezing dehydrates alum sludges and releases chemically bound water in the
sludge. When the frozen sludge thaws it retains a granular composition and precipitates to the
lagoon bottom. After the supernatant is decanted, solids with the consistency of coffee
grounds remain and are suitable for land filling.
55
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7.8 TECHNOLOGY LIMITATIONS
Lagoons frequently do not produce a dewatered sludge suitable for landfill disposal. In
particular, alum sludges do not dewater well in lagoons. The top layer of sludge dries,
hardens and seals the moisture in the layers below. Even after several years of storage, alum
sludges may need further dewatering to meet the 20 percent solids concentration required by
many landfills. Often, alum sludge is allowed to dry further after removal from the lagoon
and prior to hauling from the site. Thickened alum sludges are difficult to remove from
lagoons. Removal requires specialized dredging or vacuum equipment and knowledgeable
operators. Consequently, lagoons will not be considered for treatment/disposal of alum
sludges.
Lagoons are a land intensive dewatering process. Water treatment facilities with limited land
availability will need to consider the costs of regular lagoon cleaning and sludge disposal or
the cost of acquiring land for additional lagoons when evaluating the feasibility of this
technology. In addition, permanent lagoons that act as final disposal sites for sludges may be
considered solid waste landfills in some states. As such, the lagoons would need to meet the
design, ground water monitoring, and permitting requirements of the state's environmental
regulatory agency.
There is also a limitation on how small a lagoon can be sized. This limitation results since a
lagoon is an engineered excavation rather than simply a hole dug in the ground. To maintain
and construct the side slopes of the lagoon, the bottom surface area must be of sufficient size
to accommodate the equipment used.
7.9 STORAGE LAGOONS COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the:costs for this technology.
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7.9.1 Design Assumptions
Permanent lagoons are used to dewater lime sludges; each lagoon has a storage
capacity of ten years.
The lagoons, are earthen basins lined with a synthetic membrane and a geotextile
support fabric. They have no underdrains, but have a variable height outlet
structure to discharge supernatant.
Sludge flow rates range from 100 to 10,000 gallons per day (gpd). Although
small system lime softening units generate less than 100 gpd of sludge, the
lagoons cannot be constructed to engineering specifications at sizes less than
100 gpd. . .
Sludge is gravity fed to the lagoons from the treatment plant via 750 feet of 2-
inch diameter PVC piping buried 4 feet below the ground surface.
Decanted supernatant from the lagoon is collected and pumped to the head of
the treatment plant.
Treatment plants operate two permanent lagoons to provide 20 years of
permanent storage. Each lagoon has a 12-month storage capacity. Free liquid
is continuously decanted from the lagoon while it is accepting sludge and
returned to the head of the treatment plant. After the 12-month period, the
other lagoon is used while free liquid from the idle lagoon is decanted and
evaporated. The remaining sludge is allowed to dry before the next sludge
application.
7.9.2 Capital Components
The capital components for each storage lagoon consist of the following items:
Earthen lagoons;
Piping and fittings;
Trenching;
Decant collection tank and pump;
Electrical; . .
Instrumentation; and
Land clearing.
57
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Table 13 displays the sludge volumes, number of ponds, and total lagoon surface area used to
develop the capital cost equation for lime softening lagoons.
TABLE 13
STORAGE LAGOONS - LIME SOFTENING SLUDGE
Lime Softening
Sludge Volume
(gal/day)
100
500
1,000
2,000
4,000
10,000
Number of
Ponds
2
2
2
2
2
2
Total Surface
Area
(acres)
0.04
0.18
0.40 v
0.80
1.5
3.8
7.9.3 Operation and Maintenance Components
The operation and maintenance components for each storage lagoon include the following
items:
Labor;
Maintenance labor and materials; and
Electricity.
7.9.4 Cost Components Excluded
The following cost components are not included in the cost equations for storage lagoons:
Sludge dewatering equipment; and : _
Supernatant disposal, if the supernatant cannot be pumped to the head of the
treatment plant.
58
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Costs for sludge disposal techniques are included, in other sections of this document. Costs for
supernatant disposal, if the supernatant cannot be pumped to the head of the treatment plant,
can be determined using other sections of this document.
7.10 STORAGE LAGOON COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for six different sludge flow rates. The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). Equipment costs and
land costs are separate components in the capital cost equation to enable the user to exclude the
cost for purchasing land if it is not necessary. The total annual cost is calculated from the
capital and operation and maintenance costs obtained using the equations presented below.
Capital Costs
Y = [10,900 + 1,729 X050] + [(5.33 x 10^ X097) Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per acre (e.g., $l,000/acre)
Range: 100 gpd <; X <. 1,500 gpd
Y = [6,100 X 05° - 148,300] + [(5.33 x 104 X 097) Z]
Where: Y = $
X = gallons of sludge per day .
Z = land cost in dollars per acre (e.g., $l,000/acre)
Range: 1,500 < X <. 10,000 gpd
Operation and Maintenance
Y = 2,100 + 0.30 X050
59
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Where: ' Y = $/year
X = gallons of sludge per day
Range: 100 gpd <. X * 10,000 gpd
Total Annual .Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
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8.0 EVAPORATION PONDS
8.1 TECHNOLOGY DESCRIPTION
Evaporation ponds are a nonmechanical means by which favorable climatic conditions are used
to dewater waste brines generated by treatment processes, such as reverse osmosis and ion
exchange. The technology involves discharging the waste brines to ponds or lagoons for
storage and evaporation. The lagoons are designed with a large surface area to allow solar and
wind evaporation to dewater the brine. Pond sizes are determined by the surface area required
to evaporate the waste flows and by the desired storage capacity.
Evaporation ponds normally have an earthen construction with gradually sloping berms. Inlet
piping transfers the wastes by gravity flow, or in the case of reverse osmosis, by the operating
pressure from the treatment plant, to the lagoon. Outlet piping from the pond may be needed
in situations where the sludge loading exceeds the design capacity of the pond or for handling
overflows in emergency conditions; otherwise, no outlet is necessary. Synthetic or clay liners
may be necessary to prevent leaching of brine solutions into subsurface soil and ground water.
Site-specific soil and hydrogeologic information will determine if lining of the pond bottom
and sidewalls is required.
Depending on the total dissolved solids (TDS) concentration of the brine, solids removal may
be required from the pond on an intermittent basis. For brines with a TDS concentration
ranging from 15,000 to 35,000 milligrams per liter (mg/1), solids will accumulate within the
pond at a rate of 14 to IVi inches per year. When these solids reach a predetermined depth,
inflow to the pond is stopped and evaporation continues until a solid concentration suitable for
disposal is achieved. The solids are then removed by a front-end loader into trucks for
transport to a disposal site.
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If the water byproduct residuals managed in the ponds are determined to be hazardous waste,
these ponds are subject to compliance with the hazardous waste regulations for surface
impoundments. These regulations specify that the impoundments must be triple-lined with a
synthetic flexible membrane liner and a composite double liner. Although there are no federal
requirements specifying the design for ponds containing nonhazardous waste at this time,
regulations regarding nonhazardous waste in ponds may be enacted in the future. Therefore,
good engineering practice suggests that at a minimum a synthetic liner should be included hi
the design of the pond.-
8.2 TECHNOLOGY APPLICABILITY
Evaporation ponds are used primarily for treatment of waste brines generated by ion exchange
and reverse osmosis processes. These treatment methods produce large volume waste streams
with high dissolved solids concentrations that make other nonmechanical and all mechanical
treatment methods impractical.
Evaporation ponds dewater brine solutions quickly with few operation and maintenance
requirements; however, evaporation ponds can only be used in areas of the country with
favorable climatic conditions, such as high temperatures, low humidity, and low precipitation.
Waste brines from ion exchange and reverse osmosis require no pretreatment and are piped
directly from the treatment plant. Evaporation ponds accommodate batch or continuous
loadings and eliminate the need for equalization/holding tanks. In addition, ponds treating
wastes with low TDS concentrations will operate for several years before solids accumulation
necessitates removal.
8.3 TECHNOLOGY LIMITATIONS
Several factors limit the applicability of evaporation ponds as a sludge dewatering option.
Evaporation is a land intensive treatment requiring shallow basins with large surface areas.
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The high volumes of waste brines generated by membrane treatment processes make land
availability an important consideration. Since reverse osmosis generates large reject volumes,
the land requirements increase, which in turn, increase the cost. Consequently, evaporation
becomes impractical for most reverse osmosis treatment plants.
There is also a limitation on how small a pond can be sized. This limitation is due to that the
pond is an engineered excavation rather than simply a hole dug hi the ground. To maintain
and construct the side slopes of the pond, the bottom surface area must be a minimum size to
accommodate the equipment used.
Local climatic conditions are also important factors in determining the applicability of
evaporation. Climatic conditions primarily affect evaporation rates. A regional comparison of
the mean annual evaporation and mean annual precipitation indicates that the northeast,
southeast, Great Lakes, and coastal northwest regions of the United States have low, net
annual evaporations and are unsuitable for evaporation ponds. In addition, evaporation ponds
are generally considered unsuitable for alum and lime softening sludges.
8.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
8.4.1 Design Assumptions
The evaporation pond is used for treatment of ion exchange or reverse osmosis
brines. The influent solids concentration ranges from 1.5 to 3.5 percent by
weight. . .
Waste brines flow from the treatment plant to the evaporation pond by gravity
or by the pressure from the treatment system via 750 to 7,500 feet of schedule
40 PVC piping. Pipe diameters range from 2 to 8 inches.
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Waste brine flow rates range from 200 to 500,000 gallons per day (gpd).
Although small system ion exchange units generate less than 200 gpd, the ponds
cannot be constructed to engineering specifications at sizes less than 200 gpd.
In addition, waste brine flow rates from some small system reverse.osmosis
plants may exceed 500,000 gpd; however, the land requirements become
prohibitive at sizes over 500,000 gpd.
The pond is designed for a geographical region with a net annual evaporation
rate of at least 45 inches per year.
The pond has no outlet.
The earthen berm has two and one-half to one (2.5:1) side slopes and two feet
of free board.
Soils cut from the excavation of the basin are used to construct the berm.
The pond is constructed with a synthetic membrane liner and a geotextile
support fabric; one foot of sand is placed on top of the liner.
Piping from the treatment process is sized to discharge waste brines to the
ponds as they are generated.
The evaporation ponds are sized with sufficient surface area to evaporate the
average daily flow. The pond depth is two feet to provide solids storage
volume and to accommodate peak flows.
8.4.2 Capital Components
The capital components for each evaporation pond consist of the following items:
Evaporation ponds;
Piping and fittings;
Pumps;
Land clearing; and
Instrumentation.
Table 14 indicates the brine volumes, number of ponds, and the total required surface area
used to develop the capital cost equation for evaporation ponds.
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TABLE 14
EVAPORATION PONDS
Brine Volume .
(gal/day)
200
400
1,000
10,000
50,000
100,000
. 200,000
400,000
500,000
Number of
Ponds
1
2
2
2
2
2
4
6
3
Total
Surface Area
(acres)
0.06
0.12
0.30
3
15
30
60
,120
150
8.4.3 Operation and Maintenance Components
The operation and maintenance components for each evaporation pond include the following
items:
Labor;
Maintenance labor and materials; and
Insurance and general and administration.
8.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for evaporation ponds:
Solids removal from the pond; and
Dewatered sludge disposal
65
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Costs for sludge disposal are included in other sections of this document.
8.5 COST EQUATIONS
The cost equations for the capital components and for operation and maintenance were
developed by estimating the costs for seven different brine flow rates. The capital cost
equation calculates the total capital cost (i.e., installed capital plus indirect capital cost). The
total annual cost is calculated from the capital and operation and maintenance costs obtained
using the equations presented below.
Capital Cost
Y = [139 X °-B] + [(7.52 x 104 X 093) ZJ
Y = [Equipment Cost] -f [Land Cost]
Where: Y = $ .
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $l,000/acre)
Note: For systems less than 1,000 gallons of brine per
day, l& acre of land is required.
Range:
200 gpd ^ X s 50,000 gpd
Y = [16 X1-05] + [(4.08 x 10^ X °98) Z]
Y = [Equipment Cost] + [Land Cost]
Where:
Range:
Y = $
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $l,000/acre)
50,000 gpd < X z 500,000 gpd
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Operation and Maintenance
Y = 66 X °-61
Where:
Range:
Y = $/year
X = gallons of brine per day
200 gpd <: X <: 50,000 gpd
Y = 0.71 X 104
Where:
Range:
Y = $/year .
X = gallons of brine per day
50,000 gpd < X <. 500,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
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9.0 POTW DISCHARGE
9.1 TECHNOLOGY DESCRIPTION
Sludges, slurries, and brines generated from the treatment of drinking water are, in some ,
cases, discharged directly to publicly owned treatment works (POTW) for treatment and
disposal. This byproduct disposal technique is used most often where the water treatment
facility and the POTW are under the same management authority. The water treatment
byproducts are most often discharged to the POTW via the sewer system, but small volumes
may be stored on site and delivered to the POTW in a tanker truck. For each water treatment
facility, a conveyance system is required to access the sanitary sewer system if an adequate
system is not already in place. Installation of this system includes piping, pipe fittings, and
trenching.
The piping required to carry the byproduct stream to the outfall is the primary capital cost
associated with this treatment method. Poly vinyl chloride (PVC) piping is normally chosen
for its low cost and corrosion resistance. Pipe diameter is determined based on the maximum
expected flow and acceptable head losses. Washout points are necessary at all low points in
the discharge line to prevent clogging by accumulated sediments. Gate valves are necessary at
regular intervals to control waste stream flow hi the event of a pipe burst. In areas of winter
frost, the pipe must be laid sufficiently below grade to prevent whiter freezing.
Additional costs for treating waste in a POTW include any charges imposed by the
municipality for use of the sewer system (e.g., lift stations, piping network), basic fees
charged by the POTW, and any strength surcharges based on excessive total suspended solids
(TSS) and chemical oxygen demand (COD) in the waste stream. Most small communities
have not developed charges for excess TSS and COD in wastewater since there is not
significant industry in many of these towns. Many communities charge flat rate fees instead of
charges based on waste volumes. In addition, some communities do not charge water
68
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treatment plants for wastes sent to the POTW facility since tKey are part of the same entity.
9.2 TECHNOLOGY APPLICABILITY
Discharge into sanitary sewers is a common method of disposing'water treatment byproducts
including brines and filter backwash. Alum coagulant and lime sludges also may be
discharged to a POTW under certain conditions. The ability of the wastewater treatment plant
to accept the increased hydraulic and solids loading must be considered when determining if
POTW discharge is an appropriate disposal method. In addition, the capacity of the sewer to
handle the flow rates and solids content of the waste must be considered. The sewer must
maintain a sufficient flow velocity to prevent solids deposition.
In some cases, chemicals in the water treatment byproducts will actually aid in the treatment of
wastewaters at the POTW by acting as a settling agent. In other cases, the solids content or
other constituents hi the byproducts may hinder the wastewater treatment process and add to
the sludge disposal problem at the POTW. A thorough analysis of byproduct constituents and
volumes is required prior to selection of a POTW as a treatment and disposal option.
9.3 TECHNOLOGY LIMITATIONS
Discharging lime softening sludges to a POTW is normally not recommended due to the
dramatic increase in loading to the sludge handling system at the POTW. The disposal of
waste brines from the ion exchange and reverse osmosis process is a viable option if the
concentrated waste does not adversely affect the sewage treatment process" and if the volumes
are not excessive in comparison to the POTW capacity.
Disposal of alum sludges via a sewer is not used frequently. The high solids content of alum
sludges and the elevated concentrations of aluminum interfere with the wastewater treatment
processes. Some POTW refuse to accept alum sludges due to high solids content of the
- 69
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sludge, high aluminum concentrations, and intermittent flows. The POTWs that accept alum
sludges often charge higher rates to accept these wastes.
POTW surcharges for disposal to the sewer system substantially increase the cost of this
disposal method. POTW charges vary from a flat rate of several dollars per month to $4.50
per thousand gallons discharged. Appendix A presents POTW charges used to determine a
typical POTW charge for this document.
In all cases, the water treatment plant must have or be able to gain access to a sanitary sewer
line or have convenient truck access. Many communities, especially with populations under
500, do not maintain POTW facilities. The POTW must be designed with adequate capacity
to manage the water treatment waste and specific contaminant levels must not exceed
concentration levels specified in the POTW use permit.
9.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
9.4.1 Design Assumptions
The byproduct stream flows by gravity or under pressure from the treatment
process via PVC piping to the sewer line.
Byproduct flow rates range from 100 to' 1,000,000 gallons per day depending
on the water treatment technology.
The sewer line connection is 500 feet or 1,000 feet from the water treatment
system.
Two-inch minimum diameter pipe is used to prevent clogging. Pipe diameters
range from 2 to 6 inches. Schedule 40 PVC pipe is used.
70
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Holding tanks and lagoons are not required for small water treatment systems.
Costs are for discharge of brines and slurries and do not include TSS or BOD
surcharges.
9.4.2 Capita! Components
The capital components for each POTW discharge system consist of the following items:
Piping and fittings;
Trenching; and
Land clearing.
Table 15 indicates the brine volumes and pipe diameters used to develop the capital cost
equation for the POTW systems.
TABLE 15
POTW DISCHARGE
Byproduct
Flow Rate
(gal/day)
160
330
1,010
2,440
3,930
12,200
29,380
67,500
162,500
500,000
750,000
1,000,000
Pipe Diameter
(inches)
2
2
2
2
2
2
2
2
3
4
6
6
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9.4.3 Operation and Maintenance Components
The operation and maintenance components for each POTW discharge system include the
following items:
Labor; and
Basic POTW charges.
No maintenance requirements are assumed for this technology.
9.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for POTW discharge
systems:
Any fees charged by the POTW for the initial connection; and
Land cost.
It is assumed the water treatment facility would be able to'gain access for piping via an
easement.
9.5 COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for 12 different brine flow rates. The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). The total annual cost is
calculated from the capital and operation and maintenance costs obtained using the equations
presented below.
9.5.1 500 Feet of Discharge Pipe
Capital Costs
Y = $3,500
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Where: Y = $
X = gallons of brine per day
Range: 100 gpd <; X <; 150,000 gpd
Y = 2,700 +3.1 X
0.50
Where: . Y = $
X = gallons of brine per day
Range: 150,000 gpd < X <; 1,000,000 gpd
Operation and Maintenance
Y = [375] + [(1.83 x 10-3) 365 X]
Y = [Operating Costs] + [POTW Charges]
Where: Y = $/year
X = gallons of brine per day
(1.83 x iO"3 = POTW volume charge)
Range: 100 gpd <; X < 1,000,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
9.5.2 1,000 Feet of Discharge Pipe
Capital Costs
Y = 7,400
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Where: Y = $
X = gallons of brine per day
Range: 100 gpd <; X <; 150,000 gpd
Y = 4,800 + 6.7 X
0.50
Where: Y = $
X =-ga!lons of brine per day
Range: 150,000 gpd < X <: 1,000,000 gpd
Operation and Maintenance
Y = [375] + [(1.83 x 10-3) 365 X]
Y = [Operating Costs] + [POTW Charges]
Where: Y = $/year '
- X = gallons of brine per day
(1.83 x lO'3 = POTW volume charge)
Range: 100 gpd s X < 1,000,000 gpd
Total Annual Cost
Y - [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF.= capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
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10.0 DIRECT DISCHARGE
10.1 TECHNOLOGY DESCRIPTION
Directly discharging water treatment byproducts into surface water is a common sludge,
slurry, and brine disposal method. The technology involves piping the waste stream from the
water plant to a receiving body of water such as a river, lake or ocean. Pumping, gravity or,
in the case of reverse osmosis, pressure from the treatment plant provides the force necessary
to carry the byproduct to the receiving waters. No pretreatment or concentration of the
byproduct stream is necessary prior to discharge. The receiving waters dilute the waste
concentration and gradually incorporate the sludge or brine.
The piping required to carry the byproduct stream to the outfall is the primary capital cost
associated with this treatment method. Polyvuiyl chloride (PVC) piping is normally chosen
for its low cost and corrosion resistance. Pipe diameter is determined based on the maximum
expected flow and acceptable head losses. Washout points are necessary at all low points in
the discharge line to prevent clogging by accumulated sediments. Gate valves are necessary at
regular intervals to control waste stream flow in the event of a pipe burst. In areas of winter
frost, the pipe must be laid sufficiently below grade to prevent winter freezing.
An equalization/holding tank is optional in instances where reverse osmosis is used as the
water treatment system. It serves several purposes when disposing of treatment wastes by
direct discharge: First, the tank reduces the necessary discharge piping diameter by allowing
wastes to be continuously discharged at a lower flow rate. Second, the tank reduces the
variations in the quality of the discharged wastes by mixing the wastes generated over a period
of time. Third, the tank provides emergency storage when discharge is not possible. The size
of the holding/equalization tank will depend on the byproduct volumes and the required
number of days of storage.
- 75
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10.2 TECHNOLOGY APPLICABILITY
Direct discharge can be used for small water treatment systems where little oversight is
available. The level of operator experience and maintenance required is minimal. This
method has been used to dispose of alum and lime sludges and brines generated by reverse
osmosis and ion exchange treatment methods. Generally, there is no treatment of the solids hi
sludge or brine prior to discharge. Direct discharge requires the lowest level of oversight and
maintenance of all the treatment/disposal methods presented hi this document.
10.3 TECHNOLOGY LIMITATIONS
The primary limitations of direct discharge of water treatment plant byproducts are federal,
state, and local regulations. The discharge of waste into surface water is regulated by the
Clean Water Act. Water treatment plants are required to obtain a National Pollutant Discharge
Elimination System (NPDES) permit. Some states require toxicity testing of wastewaters as
part of their NPDES programs. Reverse osmosis brines may be acutely or chronically toxic to
aquatic life. In these cases, direct discharge of untreated wastewater should not be practiced.
A second limitation is that the byproducts can potentially have a negative effect upon the
quality of water in the receiving body. In receiving waters with low velocities, discharged
sludges will collect around the outfall. The accumulation of sludges and sediments can greatly
alter the local water quality and create an area of anaerobic activity with lower water pH and
odor problems. In addition, sudden increases in water volume and velocity can resuspend
settled'solids and shock load the receiving waters.
.Several studies have investigated the toxicity of aluminum release by alum sludges in receiving
waters. The studies indicate a trend of higher trout mortality rates in waters with higher
aluminum concentrations and a negative impact on phytoplankton productivity.
76
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10.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
10.4.1 Design Assumptions '
Byproduct flow rates range from 100 to 1,000,000 gallons per day depending
on the water system technology.
The point of discharge is 500 feet or 1,000 feet from the water treatment
system.
Two-inch minimum diameter pipe is used to prevent clogging. Pipe diameters
' range from 2 to 6 niches.
Schedule 40 PVC pipe is used.
A 1- to 2-day storage tank or lagoon is optional.
10.4.2 Capital Components
The capital components for each direct discharge system consist of the following items:
Piping and fittings;
Trenching; and
Land clearing. .
In addition, a pump, holding tank or lagoon, electrical, and instrumentation are added for the
direct discharge option with a holding tank or lagoon.
Table 16 indicates the brine volumes, pipe diameters, and tank/lagoon capacities used to
develop the capital cost equation for direct discharge.
77
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TABLE 16
DIRECT DISCHARGE
Byproduct
Flow Rate
(gal/day)
160
330
1,010
2,440
3,930
12,200
29,380
67,500
162,500
500,000
750,000
1,000,000
Pipe Diameter
(inches)
2
2
2
2
2
2
2
2
3
4
6
6
Tank or Lagoon Capacity
500-gallon tank
1,000-gallontank
2,000-gallon tank
5,000-gallontank
8,000-gallon tank
25,000-gallon lagoon
50,000-gallon lagoon
115,000-gallon lagoon
330,000-gallon lagoon
750,000-gallon lagoon
1,1 25,000-gallon lagoon
1,500,000-gallon lagoon
10.4.3 Operation and Maintenance Components
The operation and maintenance components for a direct discharge system with no holding tank
includes labor. No maintenance requirements are assumed for this technology. The operation
and maintenance components for direct discharge with a holding tank or lagoon include the
following items:
Electricity;
Labor;
Maintenance labor and materials; and
Insurance and general and administration.
78
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10.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for direct discharge
systems:
NPDES permit application and monitoring costs; and
Land cost.
It is assumed the water treatment facility would be able to gain access for piping via an
easement.
10.5 COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for 12 different brine flow rates; The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). The total annual cost is
calculated from the capital and operation and maintenance costs obtained using the equations
presented below.
10.5.1 500 Feet of Discharge Pipe
Capital Costs
Y = 3,500
Where: Y = $ .
X = gallons of brine per day
Range: 100 gpd & X < 150,000 gpd
Y = 2,700 + 3.1 X
0.50
Where: Y = $
X = gallons of brine per day
79
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Range: 150,000 gpd <. X <. 1,000,000 gpd
Operation and Maintenance
Y = 375
Where:
Y = $/year
X = gallons of brine per day
Range: 100 gpd s X < 1,000,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
10.5.2 1,000 Feet of Discharge Pipe
Capital Cost
Y = 7,400
Where:
Range:
Y = $
X = gallons of brine per day
100 gpd
150,000 gpd
Y =
4,800 + 6.7 X 05°
Where:
Y = $
X = gallons of brine per day
Range: 150,000 gpd < X <; 1,000,000 gpd
80
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Operation and Maintenance
Y = 375
Where: Y = $/year
X = gallons of brine per day
Range: 100 gpd <; X < 1,000,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
10.5.3 500 Feet of Discharge Pipe with a Holding Tank or Lagoon
Capital Costs
Y = 5,000+ 75.4 X050
Y = Equipment Cost
Where: Y = $
X = gallons of brine per day.
Range: 100 gpd ^ X 5 12,000 gpd
Y = [14,400 + 9.46 x 10'2 X] + [0.5 Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $1000/acre)
81
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Range: 12,000 gpd < X < 1,000,000 gpd
Operation and Maintenance
Y = 1,000 +0.13 X
Where:
Y = $/year
X = gallons of brine per day
Range: 100 gpd $ X * 12,000 gpd
Y = 2,600 + 1.44 x!0'2X
Where: Y = $/year
X = gallons of brine per day
Range: , 12,000 gpd < X <; 1,000,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
. Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
10.5.4 1,000 Feet of Discharge Pipe with a Holding Tank or Lagoon
Capital Cost
Y = 8,600 + 75.4X050
Where:
Range:
Y = $
X = gallons of brine per day
100 gpd ^ X ^ 12,000 gpd
82
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Y = [17,800 + 9.70 x 10'2 X] .+ [0;5 Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $1000/acre)
Range: 12,000 gpd < X * 1,000,000 gpd
Operation and Maintenance
Y = 1,000 4-0.13X
Where: ' Y = $/year
X = gallons of brine per day
Range: 100 gpd ^ X ^ 12,000 gpd
= 2,600 + 1.44xlO-2X
Where: Y = $/year
X = gallons of brine per day
Range: 12,000 gpd < X <. 500,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
83
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11.0 FRENCH DRAINS
11.1 TECHNOLOGY DESCRIPTION
French drains are a type of drainfield similar to a residential septic system used for waste
disposal. A distribution box discharges the effluent into a system of gravel-filled trenches,
known as a drainfield. French drains are constructed trenches or beds. A trench is typically
18 inches to three feet wide and a bed is 3 to 25 feet wide. Both trenches and beds have a
maximum length of 100 feet and are 1 to 2 feet deep. The beds contain % -inch to 2%-inch
gravel. Effluent runs through the pore spaces in the gravel and eventually percolates into the
surrounding soil. The size of the drainfield depends on the daily flow rates of wastewater, the
percolation rate of surrounding soil, and the depth to ground water.
Drainfields are part of a septic-type system. In this system, wastewater flows to a distribution
box. The distribution box has up to nine outlets and each outlet leads to a gravel bed.
Wastewater flows through the outlets and into the drainfield trenches. As effluent percolates
into the surrounding soil, the water quality of the effluent is improved by physical, chemical,
and biological interactions with the soil.
11.2 TECHNOLOGY APPLICABILITY
French drains are a disposal option for water treatment brines. Although there is theoretically
no limit to the amount of byproducts that can be discharged into these systems, drainfields are
usually limited to flows of 10,000 gallons per day. Higher flows can overload a system
causing drainfield failure and creating a ground water mound. These failures allow untreated
effluent into the surrounding soils and the ground water. French drains are preferred in some
areas because the drainfield needs less square footage than a standard drainfield with
perforated pipes. French drains are a versatile disposal option for
84
.
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small daily flows since they can be used in almost all climates and can be modified to be
effective with varying soil types,
11.3 TECHNOLOGY LIMITATIONS
Several factors limit the use of french drains. They are designed to handle the brines from
reverse osmosis or ion exchange; alum and lime sludges cannot be disposed via french drams.
Systems are generally limited to discharge flows of less than 10,000 gallons per day because of
the area needed for the drainfield. Higher daily flows make the system an inefficient method
of byproduct treatment due to problems such as overloading the drainfield and elevated ground
water levels. In addition, french drains are illegal in some states.
11.4 COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
11.4.1 Design Assumptions
The soil has a moderate percolation rate of 10 minutes per inch. . -
The system is gravity fed.
The maximum bed size is 100 feet in length and 25 feet wide with 10 feet
between beds.
11.4.2 Capital Components
The capital components for each french drain system consist of the following items:
Earthwork;
Gravel drainfield beds;
Piping; and
Land.
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11.4.3 Operation and Maintenance Components
The operation and maintenance components for each french drain system includes labor to
inspect the french drain system. No maintenance requirements are assumed for this
technology.
11.4.4 Cost Components Excluded
The following cost components are not included in the cost equations for french drain systems:
Collection and laboratory analysis of drainfield soil samples;
System maintenance, if necessary; and
Cost of boreholes for percolation test.
11.5 COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for five different brine flow rates; The capital cost equation calculates
the total capital cost (i.e., installed capital plus indirect capital costs). Equipment costs and
land costs are separate components in the capital cost equation to enable the user to exclude the
cost for purchasing land if it is not necessary. The total annual cost is calculated based on the
capital and operation and maintenance costs obtained using the equations presented below.
Capital Cost
Y = [2,600 + 2.92 X] + [0:5 Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $1,000 per acre)
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Range: , 100 gpd s X * 2,000 gpd
Y = [100 + 3.96 X] + [0.75 Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of brine per day
Z = land cost in dollars per acre (e.g., $1,000 per acre)
Range: 7,000 gpd < X s 10,000 gpd
Operation and Maintenance
\
Y - 375
Where: Y = $/year . .
Range: 100 gpd ^ X ^ 10,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M
Where: Y = $/year .
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
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12.0 LAND APPLICATION
Land application can be used to dispose of liquid and sludge/slurry wastes. Two land
application systems are included in this analysis: a sprinkler system for liquid waste and
transport off site for application via a specially equipped tanker truck. A general description
of land application, its applicability, and limitations is presented below. Separate cost
information is presented for land application of liquid and sludge byproducts.
12.1 TECHNOLOGY DESCRIPTION
Land application disposes water treatment byproducts by applying them directly to land
surfaces. In general, liquid sludges contain less than 15 percent solids. Liquid, pumpable,
sludge can be applied to land surfaces via spraying from a truck or sprinkler system, .injected
into the subsurface, or discharged directly to a selected land application field. Dewatered
sludge is applied by spreading the solid material over the land surface. Sludge application is
dependent on several variables, such as the crop planted in the application field and the
chemistry of the soil and sludge.
Liquid sludge can be applied to a selected land application field using various methods. Once
on the field, the sludge is treated by infiltration or overland flow, improving water quality by
physical, chemical, and biological interactions with the soil. During infiltration, liquid sludge
is allowed to percolate into the soils. Slow infiltration is used with moderately permeable soils
and the sludge is applied with sprinklers. Rapid infiltration is used with deep and highly
permeable soils, such as sands. Liquid sludge is fed continually, into a shallow basin during an
application period, which may vary between several hours to several weeks, depending on the
volume of liquid sludge. Both infiltration systems also can use underdrainage. Underdrainage
is a system of buried pipes that captures effluent for reuse or discharge into a receiving body
of water; underdrainage minimizes ground water contamination and subsurface flow of _
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leachate to adjacent properties. Overland flow is used in areas with low permeability soils!
Sludge is applied at the top of a slope and runs overland; runoff ditches collect the effluent for
reuse or discharge.
Liquid sludge can be applied by surface spraying or subsurface injection. If the application
field is near the waste-generating plant or storage lagoon, a sprinkler system can be used to
spray liquid sludge from the lagoon. If a remote application field is used, sludge must be
transported to the disposal site in a truck. The transport truck or a tanker truck may be used
to apply the sludge or may be used strictly for transport. If a tanker truck is used, the sludge
must be transferred to another specialized vehicle for application. Depending on the type of
vehicle, the sludge can be applied by spraying or subsurface injection.
Dewatered sludges are stored on site until they are transported to a disposal site. At the land
application field, the sludge is spread by a truck and tilled into the soil by a tractor.
Monitoring of soils, run off from land application, and potentially affected water resources
may be advisable to protect open land that may become cropland and to protect local water
quality. Monitoring soils for metals and/or radionuclides may be required by state and other
agencies.
12.2 TECHNOLOGY APPLICABILITY
Land application of liquid and dewatered sludges provides final disposal for lime and, to some
degree, alum sludges. The acceptability of land application is increasing and it is gaining in
popularity as a disposal method due to increased regulatory controls associated with other
disposal methods. Lime sludges can be used in farmland to neutralize soil pH in place of
commercial products. Non-food chain crops, mine reclamation areas, and forests are
preferred vegetation for sludge application. Alum sludges do not benefit the soil matrix and
should be used as fill material.
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Farmers may be reluctant to allow spreading of sludges on their fields. If farmers are willing
to use sludge, the application of sludge is seasonal, usually in the spring; however, sludges are
produced year round. Seasonal weather conditions also affect sludge application. In northern
areas, sludge application is limited to warmer months when applications can infiltrate soils or
the sludge can be injected into soils. Where the ground is frozen or covered with snow for
part of the year or applied to.farmland, sludge is stockpiled until soil conditions are
appropriate for land application.
12.3 TECHNOLOGY LIMITATIONS
There are numerous limitations to land application of sludges including chemical alteration of
the soil, seasonal conditions, and proximity of available land. Land application is not
appropriate for brines and is limited for sludges. If radionuclides are present, land application
may not be appropriate. Regulated levels of radionuclides vary from state to state and water
suppliers should contact their radiation and drinking water authorities to obtain state-specific
information.
Land application for alum sludge is limited. Alum sludge contributes little to soil
conditioning, and may actually harm soil nutrient balances. Studies indicate that alum sludges
fix phosphorous in the soil, preventing uptake of phosphorous in plants.
Application of any sludge to the land may introduce trace metals to the soil. The application
lifetime of a site is limited to when one of the trace metals reaches the maximum allowable
concentration. Due to the possibility of trace metal absorption by vegetation, non-food chain
crop fields are preferred for land application.
Land application also is limited to areas where agricultural land, grassland, or forested land is
available nearby, since transportation costs to remote disposal areas increase substantially with
distance.
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12.4 LIQUID SLUDGE LAND APPLICATION COST COMPONENTS
The following section presents the design assumptions, capital components, and the operation
and maintenance components used to prepare the costs for this technology.
».
12.4.1 Design Assumptions
The storage lagoon is constructed with a synthetic membrane liner, overlain by
12 inches of sand.
The applied sludge consists of lime or alum sludge.
The water plant is 500 feet from the storage lagoon; the sludge is gravity-fed to
the lagoon.
The lagoons are sized for 6-month storage except for the 130 gallons per day
system, which has storage capacity for one year.
The application field is cultivated farmland. The farmer uses a personally-
owned tractor and fuel to till the land following the sludge application.
Application By Truck:
The sludge is applied twice per year (spring and fall) except for the 130 gallons
per day system. Sludge is applied once per year for 130 gallons per day
system.
The sludge application is 1 inch thick.
Application By Sprinkler:
The land application rate is 14 inch per day.
The sprinkler system is a portable system with all piping above ground.
The sprinkler system has a radius of 50 feet.
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12.4.2 Capital Components
The capital components for each land application consist of the following items:
Storage lagoon;
Piping;
Land;
Electrical; and
Sprinkler system, when appropriate.
Table 17 indicates the sludge volume and pond surface areas used to develop the capital cost,
equation for the land application systems.
TABLE 17
LIQUID SLUDGE LAND APPLICATION
Sludge Volume
(gal/day)
130
1,000
5,000
10,000
Pond Surface Area
(acres)
0.05 :
0.15
0.53
0.92
12.4.3 Operation and Maintenance Components
The operation and maintenance components for land application include the following items:
Electricity;
Labor;
Sludge removal from storage pond;
Maintenance labor and materials;
Insurance and general and administration; and
Transportation and land application fees, when appropriate.
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12.4.4 Cost Components Excluded . *, ;
Costs for incorporation of the liquid sludge into the soil, if necessary, are not included in the
cost equations for liquid sludge.
12.5 LIQUID SLUDGE LAND APPLICATION COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for four different sludge flow rates. The capital cost equation
calculates the total capital cost (i.e., installed capital plus indirect capital costs). Equipment
costs and land costs are separate components in the capital cost equation to enable the user to
exclude the cost for purchasing land if it is not necessary. The total annual cost is calculated
based on the capital and operation and maintenance costs obtained using the equations
presented below.
12.5.1 Sprinkler System
Capital Cost
Y = [17,700 + 14.7 X] + [(0.2 + 7.0 x 103 X 05°) Z] + [(0.2 +
2.7 x 10-4 X) Z]
Y = [Equipment Cost] + [Pond Land Cost] + [Application Field
. Cost]
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per acre (e.g.,
$l,000/acre)
Note: for sludge flow rates <. 1,000 gpd, the total
land requirement is 0.5 acre
Range: 100 gpd ^ X ^ 10,000 gpd
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Operation and Maintenance
Y = 1,200 + 0.85 X
Where: Y = $/year
X = gallons of sludge per day
Range: 100 gpd <; X <; 10,000 gpd
Total Annual Cost
Y = [CAP x CRF] + O&M .
Where: Y = $/year
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
12.5.2 Trucking System
Capital Cost
Y = [15,200 + 13.9 X] + [0.2 + 7.0 x 10'3 X 05°) Z]
Y = [Equipment Cost] 4- [Land Cost]
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per acre (e.g.,
$l,000/acre)
Range: 100 gpd ^ X s 10,000 gpd
Operation and Maintenance
Y = 1,100 + 11.8 X
Where: Y = $/year
X = gallons of sludge per day
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Range: , 100 gpd $ X * 10,000 gpd
Total Annual Cost
Y. = [CAP x CRF] + O&M
Where: Y = $/year - :
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
12.6 DEWATERED SLUDGE LAND APPLICATION COST COMPONENTS
12.6.1 Design Assumptions
The sludge is stockpiled on site.
The sludge is transported off site for land application.
A front-end loader is used to load sludge for transport. The front-end loader is
owned by the water treatment plant.
The application field is within 25 miles of the plant.
The application field is agricultural; the fanner growing crops on the field uses
a personally-owned tractor and fuel to till the sludge into soil.
The application rate is two dry tons of sludge per acre.
12.6.2 Capital Components
The capital components for dewatered sludge land application consist of the following items:
Land for sludge stockpile; and
Land clearing.
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12.6.3 Operation and Maintenance Components
The operation and maintenance components for each dewatered sludge land application include
the following items:
Labor;
Sludge loading; and
Transportation and land application fees.
12.6.4 Cost Components Excluded
Costs for incorporation of the dewatered sludge into the soil, if necessary, are not included in
the cost equations for dewatered sludge.
12.7 DEWATERED SLUDGE LAND APPLICATION COST EQUATIONS
The cost equations for the capital components and operation and maintenance were developed
by estimating the costs for four different sludge flow rates. The capital cost equation
calculates the total capital cost (i.e., installed capital plus indirect capital costs). Equipment
costs and land costs are separate components in the capital cost equation to enable the user to
exclude the cost for purchasing land if it is not necessary. The total annual cost is calculated
based on the capital and operation and maintenance costs obtained using the equations
presented below.
Capital Cost
Y = [1.45 X087] + [0.5 Z]
Y = [Equipment Cost] + [Land Cost]
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per day
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... Range:- . 100 gpdsX s 1^000 gpd '
Y = [1.45 X 087] + [(0.33 + 1.6 x 10^ X) Z]
Y = [Equipment Cost] + [Land Cost] *
Where: Y = $
X = gallons of sludge per day
Z = land cost in dollars per day
Range: 1,000 gpd < X £ 10,000 gpd
Operation and Maintenance
Y = 150 + 28.2 X .
Where: Y = $/year
X = gallons of sludge per day
Range: 100 gpd s X ^ 10,000 gpd
Total Annual Cost
Y = [CAP x CRFJ + O&M
Where: Y = $/year , .
CAP = capital cost
CRF = capital recovery factor (e.g., 0.1175)
O&M = operation and maintenance cost
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13.0 NONHAZARDOUS WASTE LANDFILL
13.1 TECHNOLOGY DESCRIPTION ' ~" "
Nonhazardous waste landfills are used for ultimate disposal of dewatered byproduct sludges.
A landfill is an area of land or an excavation in which wastes are placed for permanent
disposal, and that is not a land application unit, surface impoundment, injection well, or waste
pile (40 CFR Part 257.2). Two forms of nonhazardous waste landfills are commonly used to
dispose of byproduct sludges: monofills and commercial nonhazardous waste landfills.
Monofills are landfills that only accept one type of waste (e.g., water treatment byproducts
sludges or incinerator ash). Commercial nonhazardous waste landfills accept a mix of
residential and industrial wastes.
Nonhazardous waste landfills are regulated by individual states and under the Resource
Conservation and Recovery Act (RCRA). Each state has specific guidelines on what types of
waste can and cannot be disposed in nonhazardous waste landfills and also determines
construction and operation criteria. In many cases, the state requirements are more stringent
than the Federal requirements under RCRA. On October 9, 1991, the U.S. EPA promulgated
new criteria for existing and future municipal solid waste landfills (56 FR 50978), a major
subset of nonhazardous waste landfills. These criteria include location restrictions, operating
criteria, design criteria, ground water monitoring requirements, corrective action
requirements, closure and post-closure care requirements, and financial assurance.
Implementation of these criteria may directly contribute to the early closure of many landfills
and increase the tipping fees charged by other landfills.
13.2 TECHNOLOGY APPLICABILITY AND LIMITATIONS
The percent solids and leaching characteristics of a sludge are the two most important
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characteristics in determining the applicability of disposal hi a nonhazardous waste landfill. *
The sludge cannot contain free liquids as defined by the Paint Filter Liquids Test (SW-846,
Method 9095). In this test, a representative 100 ml or 100 gram sample is placed in a conical
paint filter (60 mesh) and placed on a ring stand above a graduated cylinder or beaker. If any
liquid collects hi the cylinder or beaker, the sludge contains free liquids and is not appropriate
for landfilling. If liquid does not collect in the cylinder or beaker, the waste does not contain
free liquids and can be disposed hi a landfill.
In addition to passing the Paint Filter Liquids Test, the waste cannot exhibit the characteristic
of toxicity as determined by the toxicity characteristic leaching procedure (TCLP) test (40
CFR Part 261, Appendix II). In the TCLP test, an extraction is performed to determine if any
constituent is present hi the waste leachate above the regulated concentration. If any
constituents are present at concentrations greater than or equal to the TCLP limits (40 CFR
Part 261.24), the waste cannot be disposed in a nonhazardous waste landfill. If constituents
are not present above the toxicity characteristic (TC) regulatory level and the waste does not
exhibit other characteristics of hazardous waste (i.e., ignitability, reactivity, and corrosivity),
the sludge can be disposed hi a nonhazardous waste landfill.
Additional sludge characteristics such as sludge specific gravity, compaction analysis, and
shear properties also are important when determining the applicability of a sludge for disposal
in a nonhazardous waste landfill. These characteristics determine the ease of sludge handling
and the overall stability of the disposal area. In most cases, a solids content of 1520 percent
is required for landfilling, but in some cases wastes with less than 15 percent solids will be
accepted for disposal.
Many water treatment facilities currently dispose of their waste in commercial or publicly
owned landfills. Landfilling tends to be the most economical option for disposal of water
byproduct residues. Rising landfill costs, decreasing landfill availability, and increasing
environmental regulations governing waste disposal may make this option less economical.
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Because the availability of landfills is decreasing and environmental regulations are increasing,
there is increased emphasis on the benefits of monofills within the water industry. Generally,
the costs associated with the development of a monofill are less than those associated with a
municipal or industrial waste landfill. In addition, the water treatment facility limits potential
liability by controlling the type of wastes disposed at a monofill.
13.3 COST COMPONENTS
The following section presents the design assumptions and cost components used to prepare
the costs for this technology.
13.3.1 Design Assumptions
A commercial nonhazardous waste landfill.is used for sludge disposal.
: . - .Transportation distance varies from 5 to 50 miles.
' ' - There is no economy of scale for large waste volumes.
All wastes pass the Paint Filter Liquids Test.
- . The waste does not exhibit the characteristics of ignitability, corrosivity,
reactivity, or toxicity.
13.3.2 Cost Components
The cost components for non-hazardous waste landfill consist of the following items:
Commercial nonhazardous waste landfill tipping fee; and
Transportation fees.
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13.4 TOTAL ANNUAL COST EQUATION
Y = [35 X] -J- [2.48 + 0.16 Z] X
Y = [Disposal] + [Transportation]
Where: Y = $/year
X = Tons of sludge requiring disposal per year
Z = Transportation distance from 5 to 50 miles
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14.0 HAZARDOUS WASTE LANDFILL ....:.
14.1 TECHNOLOGY DESCRIPTION
Hazardous waste landfills are used for ultimate disposal of hazardous wastes (including listed
and characteristic wastes). For water treatment byproduct sludges specifically, hazardous
waste landfills are used for the disposal of sludges exhibiting one or more characteristics of
hazardous waste (ignitability, corrosivity, reactivity, and toxicity). A hazardous waste landfill
is a disposal facility where hazardous waste is placed in or on land and which is not a waste
pile, a land treatment facility, a surface impoundment, an underground injection well, a salt
dome formation, a salt bed formation, an underground mine, or a cave (40 CFR Part 260.10).
Hazardous waste landfills are regulated by the Federal government under RCRA or by
individual states where the state has received RCRA authorization.
Hazardous waste landfills must be permitted in accordance with the hazardous waste permit
regulations (40 CFR Part 270). The hazardous waste landfill regulations specify that landfills
must be designed with a synthetic flexible membrane liner and composite double liner. In
addition, the landfill must have a leachate collection system above the top liner and a leachate
detection system between the top liner and bottom composite liner. The containment system
for a hazardous waste landfill, in descending order starting with the component closest to the
waste, consists of a 1-foot protective soil layer, a geotextile filter fabric, a leachate collection
system (a 1-foot sand layer with drainage pipes), a 30-mil HOPE liner, a leachate detection
system (a 1-foot sand layer with drainage pipes), a 30 mil-HDPE liner, and a 3-foot layer of
compacted clay, which has a hydraulic conductivity < 1 x 10'7 cm/sec. Leachate collected
from the landfill must be tested to determine if it is a hazardous waste. If the leachate is
determined to be a hazardous waste, it must be managed as a hazardous waste.
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14.2 TECHNOLOGY APPLICABILITY AND LIMITATIONS
The leaching characteristics and the presence of free liquids are the two most important
characteristics in determining the applicability of sludge disposal hi a hazardous waste landfill.
Water treatment byproducts that exhibit the characteristic of ignitability, corrosivity,
reactivity, or toxicity require disposal hi a hazardous waste landfill. Typically, water
treatment byproducts are not ignitable, reactive, or corrosive, but may exhibit the
characteristic of toxicity. The TCLP test (40 CFR Part 261, Appendix H) is used to determine
if wastes are toxic. In the TCLP test, the extraction is performed to determine if any
constituent is present in the waste leachate above the regulated concentration. If any
constituents are present at concentrations greater than or equal to the TC limits (40 CFR Part
261.24), the waste is hazardous and requires disposal hi a hazardous waste landfill. If no
constituents are present above the regulatory level and the waste does not exhibit other
characteristics (i.e., ignitability, reactivity, and corrosivity), the sludge can be disposed in a
nonhazardous waste landfill.
In addition, the sludge cannot contain free liquids as defined by the Paint Filter Liquids Test
(SW-846, Method 9095). In this test, a representative 100 ml or 110 gram sample is placed in
a conical paint filter (60 mesh) and placed on a ring stand above a graduated cylinder or
beaker. If liquid collects in the cylinder or beaker, the sludge contains free liquids and is not
appropriate for landfilling. If no liquid collects in the cylinder or beaker, the waste does not
contain free liquids and can be disposed in a landfill without further dewatering. If the waste
contains free liquids, it must be stabilized or treated by another method to remove free liquids
prior to disposal in a landfill.
The Hazardous and Solid Waste Amendments of 1984 restrict the land disposal of untreated
hazardous wastes. The land disposal restrictions for Third Third wastes (55 FR 22520)
promulgated treatment standards for wastes exhibiting characteristics of hazardous waste (i.e.,
ignitability, corrosivity, reactivity, and toxicity) that require wastes to meet specified
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concentration standards prior to land disposal. In general," for sludges exhibiting the TC
characteristic, the sludges must be stabilized prior to land disposal to meet the concentration
standard. Other treatment methods are acceptable as long as the waste contains TC
concentrations at or below the level specified hi the Third Third Final Rule prior to land
disposal. The additional treatment required by the Land Disposal Restrictions Rule
significantly increases the cost of hazardous waste disposal.
14.3 COST COMPONENTS
The following section presents the design assumptions and cost components used to prepare
the costs for this disposal technology.
14.3.1 Design Assumptions
A commercial hazardous waste landfill is used for sludge disposal. .
Transportation distance varies from 200 to 500 miles.
There is no economy of scale for large waste volumes.
All wastes pass the Paint Filter Liquids Test or if they fail the Paint Filter
Liquids Test, diey are stabilized prior to disposal.
The waste fails the TCLP test.
Some wastes require stabilization prior to disposal to meet the Land Disposal
Restrictions Treatment Standards for toxicity characteristic (TC) wastes.
14.3.2 Cost Components
The cost components for hazardous waste landfill consist of the following items:
Hazardous waste landfill charges;
Stabilization charges; and
Transportation fees.
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14.3.3 Cost Components Excluded .
The following cost components are not included in the cost equations for hazardous waste
landfills:
Generator notification requirements;
Manifest requirements; and
OtherRCRArequirements, as applicable. . . -.
14.4 TOTAL ANISfUAL COST EQUATION
14.4.1 Hazardous Waste Disposal
Y =[200 X] + [(7.9 + 0.22 Z) X]
Y= [Disposal] + [Transportation]
Where: Y = $/year
X = Tons of sludge requiring disposal per year
Z = Transportation distance between 200 and 500 miles
14.4.2 Stabilization and Hazardous Waste Disposal
Y = [400 X] + [(7.9 + 0.22 Z) X]
Y = [Stabilization/Disposal] + [Transportation]
Where: Y = $/year
X = Tons of sludge requiring disposal per year
Z = Transportation distance between 200 and 500 miles
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15.0 RADIOACTIVE WASTE DISPOSAL
15.1 SOURCES OF RADIOACTIVITY IN DRINKING WATER
Radionuclides, such as radium, uranium, and radon, naturally occur in drinking water sources
in the United States. Radium is found in ground waters and is most common in the Midwest
and Florida. Uranium is found in sandstone and phosphate rock ground waters primarily in
western states.
Presently, Federal regulations have established maximum contaminant levels (MCLs) only for
radium, gross alpha radiation and beta/photon emitters. In 1976, a drinking water standard for
combined radium of 5 picocurries per liter (pCi/L) was set by the U.S. EPA. It was estimated
that 1,000 community water supplies exceeded the radium standard in the U.S.; most of which
were groundwater systems with capacities of 0.5 million gallons per day or less. Federal
MCLs have not yet been established for radon or for natural uranium, although regulations are
under development. In addition, waste containing more than 0.05 percent of natural uranium
may be regulated as a "source material" under the Atomic Energy Act. Because of existing
regulations, radium contamination will be the focus of this section.
In 1990, the EPA issued guidance entitled "Suggested Guidelines for the Disposal of Drinking
Water Treatment Wastes Containing Naturally Occurring Radionuclides." The guidance,
which is currently being revised, is designed to provide water suppliers and state and local
governing agencies with some assistance. The guidance provides recommendations and
summarizes existing regulations and criteria used by EPA and other agencies in addressing the
disposal of fadionuclides generated by industries other than the water treatment industry.
Because this guidance is not regulation and regulations vary from state to state, water suppliers
should contact radiation and drinking water authorities within their state for additional, state-
specific information.
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A water supply system with radium levels that exceed regulations has several options to bring
the radium levels below the Federal MCLs. The supply can develop a new water source,
dilute the radium rich water with less rich water from another source, or treat the water to
reduce radium levels. A water treatment plant should carefully study the cost and feasibility of
radium removal and disposal of radium-contaminated sludges before choosing to install a
radium removal treatment technology.
15.2 RADIUM REMOVAL
Treatment processes that remove radium from drinking water include lime softening, ion
exchange, reverse osmosis, manganese green sand filters, and radium selective resins. These
processes have 80 to 98 percent removal efficiencies and concentrate the radium removed from
the treated water in the treatment media and backwash, brine, and sludge wastes.
Radium wastes generated by drinking water treatment are identified as naturally occurring
radioactive material (NORM). The United States does not have Federal regulations governing
the disposal of NORM. The United States Nuclear Regulatory Commission (NRC) is
mandated to regulate the disposal of high-level and low-level radioactive wastes generated in
the United States. The disposal of NORM is not licensed by the NRC because it is not a
manmade radioactive waste and does not fall under NRC jurisdiction. The EPA has proposed
standards to control the disposal of NORM wastes with radionuclide concentrations greater
than 2000 pCi/g (dry weight). Individual states also have proposed regulating the handling
and disposal of NORM. Presently, there are no state or Federal regulations governing the
disposal of radioactive water treatment wastes and it may be several years before proposed
regulations are adopted. However some states, including Texas, Louisiana, Wisconsin, and
Colorado, have disposal regulations or proposed state requirements that pertain to Naturally
Occurring and Accelerator-Produced Materials (NARM) that limit the discharge of wastes
containing radionuclides into the environment. .
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The radium content in wastes generated by water treatment processes-will depend upon the
type of wastes, removal efficiency of the process, and the volume of waste generated. Filter
backwash water will have little or no elevated radium concentrations. Brines generated from
reverse osmosis and ion exchange methods will have a wide variety of radium concentrations.
Sludge and solid wastes will have the greatest radium concentrations.
15.3 LOW-LEVEL RADIOACTIVE WASTE DISPOSAL
There are several disposal options for NORM wastes generated by water treatment plants.
Most of these disposal methods, including direct discharge to surface waters, discharge to
sanitary sewers, land application, and landfilling have been discussed in detail in previous "
sections. When state and local regulations permit disposal of water treatment plant NORM by
these methods, the costs of disposal should be similar to non-NORM sludge disposal costs!
One additional disposal option, sending wastes to a low-level radioactive disposal site, has not
been mentioned previously and will be discussed in detail here. It should be noted that this
will usually be a final option for a water treatment plant that cannot develop a new water
source or dilute the radium-rich water with less rich water from another source.
*
For plants that do not have alternative water sources or cannot reduce the radium in their
source by dilution, radium containing waste will require disposal. It is assumed that the final
disposal product will consist of a resin or filter media used specifically to capture the radium
in the feed water rather than the brine or sludge resulting from more general water treatment.
The brines and sludges will not require this special disposal since the radium concentration in
these wastes is typically below regulated levels. Consequently, the waste volumes will be
significantly lower than those specified for general water treatment.
There are currently three low-level radioactive waste disposal sites operating in Nevada/ South
Carolina, and Washington, and one NORM disposal site operating in Utah. Each low-level
site bases waste disposal costs on several factors including state of origin of the waste, type of
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waste, and measured radioactivity at the container surface. All disposal facilities are located
in a regional pricing compact. The Low-Level Radioactive Waste Policy Amendments Act
(LLRWPAA) of 1985 authorized the formation of regional compacts and a system of
incentives and penalties to ensure that states and compacts will be responsible for their own
waste after January 1, 1993. States located in a compact with an operational waste disposal
facility pay the lowest disposal costs while states located outside of the compacts with disposal
facilities pay a disposal surcharge of $40 or $120 per cubic foot (approximately $300 to $900
per 55-gallon drum). The NORM disposal site is not part of a pricing compact and does not
add surcharges.
Most water byproduct treatment processes do not generate wastes with radiation levels high
enough to be classified as a low-level radioactive waste and that possibility should be
minimized through proper treatment design. In some instances, a treatment process may
concentrate the radionuclides in activated carbon or in a highly selective resin to levels
necessitating disposal at a low-level or NORM site. The choice of a disposal location for
NORM is made by the waste generator or by a state regulatory agency. :. ''
Several steps must be taken when disposing of a radioactive waste solid to meet the
requirements of the disposal facility and the various regulating agencies. First, a low-level or
NORM disposal site which will accept the. waste is located. Second, all free standing liquids
are removed. Third, materials are packaged in 55-gallon drums with 4 mil liners. Fourth, all
necessary permitting, shipping, and packaging paperwork is completed and finally, the drams
are sent to the disposal site by a Department of Transportation (DOT)-approved carrier with
proper care and instructions.
There are several ways a small volume waste generator can arrange for the disposal of wastes
at a low-level or NORM site. A small volume waste generator can package the waste
materials themselves. After packaging, a collection service (such as those that pick up
radioactive wastes from hospitals) can be contracted to pick up the drums, perform a radiation
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survey, complete the labelling and paperwork, and deliver the drums to the disposal sito-If a
waste generator does not want to be involved in the waste packaging and disposal, a broker
can be hired to complete the process. Brokers will send trained personnel to solidify or absorb
and package all materials. The broker will arrange for transportation and disposal and .
complete all necessary paperwork. The broker's charges cover all costs including
mobilization, transportation of packaged drums, and disposal. Brokers also can be hired to
provide oversight and permitting expertise while the waste generators supply the labor and
materials necessary for packaging.
15.4 COST INFORMATION
Radioactive waste disposal costs are not included within this report.,.These costs may be
obtained from EPA's guidance entitled "Suggested Guidelines for the Disposal of Drinking
Water Treatment Wastes Containing Naturally Occurring'Radionuclides" that is scheduled for
release in 1993. This revision of the Guidelines, which originally were issued in. 1990, will
provide cost-related information, recommendations, and a summary of existing regulations and
criteria used by EPA and other agencies in addressing the disposal of radionuclides.
16.0 REFERENCES
Ag-Chem Equipment; contacted by Allan Timm and Mary Rooney, DPRA. Concerning
terragators. 29 July 1992.
American Water Works Association. Sludge: Handling and Disposal. Denver, CO:
American Water Works Association, 1989.
American Water Works Association. Slib. Schlamm. Sludge. KIWA Ltd., 1990.
Aquino, John T. "NSWMA Releases Expanded Tipping Fee Survey." Waste Age. ±
December 1991," pp. 24-28.
110
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Armbrust, Andy, U.S. Ecology; contacted by Mary Rooney, DPRA. Concerning low-level
waste disposal costs. 27 July 1992.
Brown, Denise, U.S. Ecology; contacted by Mary Rooney, DPRA. Concerning low-level
waste disposal costs. 24 July 1992.
Camp, John, Rain for Rent; contacted by Kristina Uhlig, DPRA. Concerning sprinkler
systems. 21 August 1992.
Clark, Viessman, Hammer. Water Supply and Pollution Control. Harper and Row. 1977.
Clingingsmith, Larry, C.P. Environmental; contacted by Mary Rooney, DPRA. Concerning
lagoon dredging costs. 19 August 1992.
Cornwell, Bishop, et al. Handbook of Practice. Water Treatment Plant Waste Management.
Denver, CO: American Water Works Association, June 1987.
Crase, Arvil, U.S. Ecology; contacted by Mary Rooney, DPRA. Concerning low-level
waste disposal costs. 27 July 1992.
Fraigh, Al, American Materials Corporation; contacted by Mary Rooney, DPRA.
Concerning sand and gravel costs. 23 August 1992.
Gavzonetti, Gary, Centrisys Corporation; contacted by Mary Rooney, DPRA. 13 August
1992. Contacted by Allan Timm, DPRA. 28 August 1992. Concerning centrifuge
applications and cost.
Gregory, Sue, Biogro; contacted by Kristina Uhlig, DPRA. Concerning liquid and
dewatered sludge land application costs. 18 August 1992.
Gross, Rod, Envirex, Inc.; contacted by Mary Rooney, DPRA. Concerning gravity
thickener application and costs. 24 August 1992.
Gruidi, Dan, Robert D. Hill; contacted by Mary Rooney, DPRA. Concerning density of
granular salt. 30 July 1991.
Gumerman, Robert C., Bruce E. Burris, and Sigurd P. Hanser. Small Water Treatment
System Costs. Park Ridge, NJ: Noyes Data Corporation, 1986.
Hahn, Norman, Wisconsin Department of Natural Resources; contacted by Mary Rooney,
DPRA." Concerning radioactive sludge disposal options. 22 July 1992.
.111
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Hahn, Norman. "Disposal of Radium Removal from Drinking Water." American Water
Works Association Journal. 1986, pp. 137-144.
Haraldson, Gary, Lakewood Water Treatment Plant; contacted by Mary Rooney, DPRA.
Concerning use of sand drying beds. 11 August 1992. .
Harrison, Jack, Chem Nuclear; contacted by Mary Rooney, DPRA. Concerning low-level
radioactive waste disposal costs. 27 July 1992.
Higgins, Kirt, Envirocare; contacted by Mary Rooney, DPRA. Concerning NORM disposal
costs. 27 August 1992.
Hill Reference Library; contacted by Greg Kvaal, DPRA. Concerning bulk and bagged lime
costs. 19 August 1992.
Hoeft, Mark, J&M Custom Waste; contacted by Kristina Uhlig, DPRA. Concerning liquid
sludge land application costs. 17 August 1992.
Huffman, Tom, Hydro Engineering Inc.; contacted by Kristina Uhlig, DPRA. 19 August
1992. Contacted by Allan Tim, DPRA. 31 July4992. Concerning sprinkler systems.
Koeckeritz, Om, Koeckeritz Excavating; contacted by Kristina Uhlig, DPRA. Concerning
septic field design and cost. 21 August 1992.
Krall, Tom; Mobile Dredging and Pumping; contacted by Mary Rooney, DPRA.
Concerning lagoon dredging costs. 26 August 1992.
Kramer, Brian, Metro Ag Inc.; contacted by Kristina Uhlig, DPRA. Concerning liquid and
dewatered sludge land application costs. 20 August 1992.
Krizan, William. "Second Quarterly Cost Report." Engineering News-Record. 29 June
1992, p. 33.
Kuehne, Susan, Star Systems Filtration Division; contacted by Mary Rooney, DPRA.
Concerning filter press costs. 17 August 1992. :
Lowry, Jerry, Lowry Engineering; contacted by Mary Rooney, DPRA. Concerning low-
level radioactive water disposal options. 21 July 1992.
Meltzer, Jim, Northern Gravel Co.; contacted by Mary Rooney, DPRA. Concerning sand
and gravel costs. 4 August 1992.
112
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Metcalf & Eddy, Inc. Wastewater Engineering: Treatment. Disposal, Reuse. 2nd ed.
Boston, MA: McGraw-Hill, 1972.
Minnesota Pollution Control Agency, Water Quality Division. Individual Sewage Treatment
Systems Standards - Chapter 7080. July 1989.
Mohr, Bob, Chem Nuclear; contacted by Mary Rooney, DPRA. Concerning low-level
radioactive waste disposal costs. 24 August 1992.
Mueller, Donald, LWT Inc.; contacted by Mary Rooney, DPRA. Concerning lagoon
dredging costs. 26 August 1992.
Nidetz, Jeff, Cyrigan; contacted by Mary Rooney, DPRA. Concerning reverse osmosis and
ion exchange treatment processes. 12 August 1992.
Nuclear Regulatory Commission Information Digest. 1992 Edition. NUREG-1350, Volume.
4. March 1992.
Ohio River Valley Water Sanitation Commission. A Study of Wastewater Discharges
from Water Treatment Plants. April 1981.
Parrotta, Marc. "Radioactivity in Water Treatment Wastes: A USEPA Perspective."
American Water Works Association Journal. April 1991, p. 134
Parrotta, Marc, US EPA; contacted by Pat Martz Kessler, DPRA. Concerning the
Suggested Guidelines for the Disposal of Drinking Water Treatment Wastes Containing
Naturally Occurring Radionuclides. March 3, 1993.
Perez, Yvonne, U.S. Ecology; contacted by Mary Rooney, DPRA. Concerning low-level
radioactive waste disposal costs. 23 July 1992.
Peterson, Bruce, Peterson Ag Service; contacted by Kristina Uhlig, DPRA. Concerning
liquid sludge land application costs. 18 August 1992.
R.S. Means Company, Inc. 1992 Means Site Work and Landscape Cost Data, -llth ed.
Kingston, MA: Construction Consultants and Publishers, 1991.
R.S. Means Company, Inc. 1992 Means Mechanical Cost Data. 15th ed. Kingston, MA:
Construction Consultants and Publishers, 1991.
R.S. Means Company, Inc. 1992 Means Building Construction Cost Data. 50th ed.
Kingston, MA: Construction Consultants and Publishers, 1991.
113
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Richardson Engineering Services, Inc. Process plant Construction Estimating Standards,
Mechanical and Electrical. Vol. 3. Mesa, AZ. 1990.
Richardson Engineering Services, Inc. Process Plant Construction Estimating Standards^
Process Equipment. Vol. 4. Mesa, AZ. 1990.
Robertson, R.F. and Y.T. Lin. "Filter Washwater and Alum Sludge Disposal: A Case
Study." Proceedings AWWA Seminar on Water Treatment Waste Disposal Seminar,
(June 25, 1978), 4, 1-8.
Sadowski, Greg, Sharples/ALFA-LAVAL Company; contacted by Mary Rooney, DPRA.
Concerning scroll centrifuge costs. 19 August 1992.
Seefert, Ken, Croixland Excavating; contacted by Kristina Uhlig, DPRA. Concerning French
drains. 24 August 1992.
Tabor, Paul, Simpson Filtration Inc., contacted by Allan Timm, DPRA. Concerning filter
press costs. 29 July 1992.
U.S. Environmental Protection Agency, Center for Environmental Research Information.
Process Design Manual - Land Treatment of Municipal Wastewater. EPA-625/1-81-
013. October 1981.
U.S. Environmental Protection Agency, Office of Drinking Water. Radionuclide Removal
for Small Public Water Systems. EPA 570/9-83-010. June 1983.
U.S. Environmental Protection Agency, Office of Research and Development. Design
Manual - Onsite Wastewater Treatment and Disposal Systems. EPA-625/1-80-012.
October 1980.
U.S. Environmental Protection Agency, Office of Research and Development. Innovative
and Alternative Technology Assessment Manual. EPA-430/9-78-009. February 1980.
U.S. Environmental Protection Agency, Office of Research and Development. Process
Design Manual - Land Application of Municipal Sludge. EPA-625/1-83-016. October
1983.
U.S. Environmental Protection Agency. The Cost Digest: Cost Summaries of Selected^
Environmental Control Technolqgies. Prepared by Radian Corporation for the Office
of Research and Development. EPA-600/8-84-010. October 1984.
114
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U.S. Environmental Protection Agency. Waste By Products Document in Support of Drinking
Water Treatment BAT Cost Analyses. Prepared by Malcolm Pirnie, Inc. for the Office
of Drinking Water. April 1990.
U.S. Environmental Protection Agency, Office of Drinking Water. Technologies for
Upgrading Existing or Designing New Drinking Water Treatment Facilities.
EPA/625/4-89/023. March 1990.
U. S. Nuclear Regulatory Commission. Regulating the Disposal of Low-Level Radioactive
Waste. A Guide to the Nuclear Regulatory Commission's 10 CFR Part 61. Office of
Nuclear Material and Safeguards.
Vetter, Gerry, Carylon Company; contacted by Kristina Uhlig, DPRA. Concerning
dewatered sludge land application costs. 26 August 1992.
Viessman, Warren, Jr., et al. Introduction to Hydrology. 2nd Ed., New York, NY:
Harper & Row, 1977.
"Wage Rates for Key Construction Trades." Engineering News - Record. 29 June 1992,
p. 57.
Webber, Mike, Farmers Union Co-Op; contacted by Kristina Uhlig, DPRA. Concerning
liquid sludge land application costs. 17 August 1992.
Wilcox, Terry, Walder Pump and Equipment; contacted by Mary Rooney, DPRA.
Concerning gravity thickeners. 24 August 1992.
115
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APPENDIX A
POTW CHARGES
A-l
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APPENDIX A
POTW CHARGES
The POTW charges presented in Chapter 9 of this document are based on a limited sampling
of POTW rates conducted for this analysis and a survey published by the League of Minnesota
Cities. Table 1 presents the results of the telephone sample and Table 2 presents selected
results from the League of Minnesota Cities Survey. Three of the cities contacted during the
telephone sample do not charge to accept wastes from water treatment plants and a fourth does
not have a wastewater treatment plant. In addition, many of the POTWs contacted during the
telephone sample and by the League of Minnesota Cities charge a flat rate per month with no
additional charges for higher flow rates. :
A-2
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TABLE 1
SEWER RATES - SMALL CITIES
TELEPHONE SAMPLE
City
Gordb
Clarkdale
Westeliffe
Anthony
Bird City
Livermore Falls
Ada
Cannon Falls
Circle Pines
Deer River
Harlem
Crooksville
Agate Beach
State
Alabama
Arizona
Colorado
Florida
Kansas
Maine
Minnesota
Minnesota
Minnesota
Minnesota
Montana
Ohio
Oregon
Population
2,112
2,144
324
900
467
3,500
1,971
2,653
3,321
907
1,023
2,766
700
Sewage Fee Charged
Business: $7.50/month if < 12 employees;
$15/month if > 12 employees
Residential: $10/month
Residential: $15/month x unit (up to 6 "
units)
No sewer system - well & septic system . ., .
$8.50/month
$15 + $1.87/1 ,000 gallons
$3/month for sewer line + $3/unit if
apartment + $.67/1,000 gallons
Minimum: $9. 10/2 months + $1.48/1,000
gallon BOD: $44.57/100 pounds Suspended
solids: $28.93/100 pounds; Industrial
surcharge: $.47/1 ,000 gallons
$5.50/month + $1.10/1, 000 gallons
$9.00 base rate
Minimum: $7.84/month/meter Gallons used
during winter x 12 x .00325 + 1068
$10.80/2,000 gallons + $4.45/1,000
gallons (2K+)
$5.25/1,000 gallons +
$1/1 ,000 gallons (IK +) +
$.25 surcharge > 10,000 gallons +
$1.55/1,000 gallons for BOD over 600 mg.
A-3
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TABLE 2
SEWER RATES
LEAGUE OF MINNESOTA CITIES SURVEY
City
Dent
Goodridge
Kettle River
Mapleview
Steen
Beaver Bay
Big Falls
Breezy Point
Center City
Hartland
Motley
Peterson
Plummer
Rose Creek
Rothsay
Round Lake
Wood Lake
Argyle
Battle Lake
Bigfork
Butterfield
Population
167
191
174
235
154
283
490
384
458
322
444
285
353 '
380
476
480
420
741
708
541
634
Sewage Fee Charged
$10 (commercial)
$5 (residential)
$25 (commercial)
$18/quarter + $.20/1,000 gallons (over 2.3K)
$18/quarter
$16/month (residential)
$16/month (commercial)
$100/year
$207 < 7,999 gallons
$26.08/8,000 gallons + $.76/1,000 gallons (8K+)
$12/quarter
$1.26/1,000 gallons + TSS + BOD (not
listed)
$7.50/month (June-Aug.)
or $20/month (other mos.)
$5 + $.35/1, 000 gallons (commercial)
$5 .+ $1/1, 000 gallons (1K+)
$1.24/1 ,000 gallons
$10/4,000 gallons + 1.50/1,000 gal. (4K+)
$5/month (Residential)
$.80/1, 000 gallons
$10.28 + $.723/1,000 gallons
$19.50/quarter
$12 (Residential)
A-4
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TABLE 2
SEWER RATES
LEAGUE OF MINNESOTA CITIES SURVEY
(continued)
City
Carver
Freeport
Goodhue
Rollingstone
Siver Lake
St. Clair
Adams
Richmond
: Walnut Grove
Birchwood
Maple Lake
Preston
Appleton
Blooming Prairie
Cold Spring
Lake Crystal
Lakefield
Lexington
Mapleton
Pine Island
Population
642
563
657
528
698
655
797
867
753
1,059
1,132
1,478
1,842-
1,969
2,294
2,078
1,845
2,150
1,576
1,977
Sewage Fee Charged
$3.50/1,000 gallons (Jan., Feb., March)
+ 2.70/1, 000 gallons
$7 (Residential)
Water usage x .50 + $24
$20/quarter
$2.57/1, 000 gallons .'""'
$20 + $1.50/1, 000 gallons (6K+)
$4.80 (minimum)
$6.30 (0-5K) -f $1.26/1,000 gallons (5K+) .
$20
,$33/quarter .- _
$12.71 (0-3K) + $3 . 10/1 ,000 gallons (3K+)
$1.55/1, 000 gallons
$21.75 + $1.93/1, 000 gallons
$4.50 + $1.26/1, 000 gallons
$11 (0-6K)
+ $1.60/1 ,000 gallons (6K+)
$1. 25/1 ,000 gallons (0-20K) + $.50/1, 000 gallons
(20K+)
$1.97/1, 000 gallons + 1.13
$33
$15 - -
$1.63/1, 000 gallons
A-5
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TABLE 2
SEWER RATES
LEAGUE OF MINNESOTA CITIES SURVEY
(continued)
City
Population
Sewage Fee Charged
Ely
, 4,820
$2.00/1,000 gallons
Newport
3,323
$8.58 (0-10,000 gallons)
$10.66 (10-15,000 gallons)
$16.12 (15-25,000 gallons)
$26.00 (25-40,000 gallons)
$36.40 (40-55,000 gallons)
$49.40 (55-75.000 gallons)
A-6
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.... . TECHNICAL REPORT DATA , , *
(.. , (fleax read Instructions on, [he reverse before compleling) , ,
1. REPORT NO. ='» 2J. »-' <"<'# "*!-.{ iV **-'**' "
£SW &//-?- 93-00 1 - .: '" ' * ' ' fc 1
4. TITLE AND SUBTITLE ' ''
Small IWater System Byproducts
Treatment and Disposal Cost Document
7. AUTHOR(S)
DPRA Incorporated
9. PERFORMING ORGANIZATION NAME AND ADDRESS
DPRA Incorporated
IDUU First National Bank Building
332 Minnesota Street
St. Paul, MN 55101
12. SPONSORING AGENCY NAME AND ADDRESS
IS. SUPPLEMENTARY NOTES :.\:.
Ben Smith-Project Manager
1 ' 3. RECIPIENT'S ACCESSION NO.
<
5. REPORT PAT;E^« _
April 1993
6. PERFORMING ORGANIZATION CODE
EPA/OGWDW .«/ :..- : .
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
.68-CQ-0020
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
16. ABSTRACT ....... -
This document provides a summary of techniques for projecting the
costs of frater treatment residuals treatment and disposal. It is a
generalized report developed for use in the evaluation of prospec-i '
tive drinking water regulatory alternatives.
17- KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS b.lDENTIFI!
drinking water treatment costs/
residuals management, cost
analysis ,
18. OlSTRIBUTtON STATEMENT 19. SECURH
20. SECURI1
!RS/OPEN ENDED TERMS C. COSATI Field/Croup
Y CLASS (This Rfportl 21. NO. OF PAGES
131
V CLASS iTIiispafel 22. PRICE
6PA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
J
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