EPA-43 0/9-75-018
SEPTEMBER 1975
                 TECHNICAL REPORT
      WASTEWATER SLUDGE  UTILIZATION
             AND DISPOSAL COSTS
          U.S. ENVIRONMENTAL PROTECTION AGENCY
            Office of Water Program Operations
                Washington. D.C. 20460
                                           MCD-12

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                         EPA REVIEW NOTICE


This report has been reviewed by the Environmental Protection Agency

and approved for publication.  Approval does not signify that the

contents necessarily reflect the views and policies of the Environ-

mental Protection Agency, nor does mention of trade names or commercial

products constitute endorsement or recommendation for use.
                               NOTES
          It is the intention of the Environmental Protection
          Agency to revise and update this Technical Report as
          more technical information becomes available.   The
          most valuable source of information for revisions
          will be the actual experiences of those using  the re-
          port.  All users are encouraged to submit such infor-
          mation to the Director of the Municipal Construction
          Division (WH-547), Office of Water Program Operations,
          Environmental Protection Agency, Washington, D.C.  20460.

          Methods of estimating costs and evaluating the cost-
          effectiveness of conventional wastewater treatment
          works have been developed in a separate document, en-
          titled, A Guide to the Selection of COST-EFFECTIVE
          WASTEWATER TREATMENT SYSTEMS, NO. EPA-430/9-75-002,
          MCD-11.

          Methods of estimating costs and evaluating the cost-
          effectiveness of land-application systems have been
          developed in a separate document, entitled, Technical
          Report, Costs of Wastewater Treatment by Land  Appli-
          cation, No. EPA 430/9-75-003, MCD-10.

          To order publications MCDT10, MCD-11,  or MCD-12 write to:

                      General Services Administration (8-FY)
                      Centralized Mailing List Services
                      Bldg. 41, Denver Federal  Center
                      Denver, Colorado  80225

          Please indicate the MCD No. and title of publication.

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EPA-430/9-75-015
SEPTEMBER 1975
       WASTEWATER SLUDGE UTILIZATION
               AND DISPOSAL  COSTS
                           BY
                    Timothy G. Shea, Ph.D.
                     John D. Stockton
                  EPA CONTRACT P5-01-205
                         Prepared for

                   Municipal Technology Branch
                   Municipal Construction Division
                 Office  of Water Program Operations
                 U.S. Environmental Protection Agency
                    Washington, D.C.  20460
                                                  MCD-12

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                                 ABSTRACT

     A flow sheet describing various sludge utilization and disposal
alternatives is presented.   Amortized capital  and O&M costs are shown
for plant capacities ranging from 1  - 1000 MGD.   From this informa-
tion preliminary comparisons of the  cost-effectiveness of various  sludge
utilization and disposal alternatives can be made.   The report pro-
vides supplementary information which when combined with the Technical
Report:  A Guide to the Selection of Cost-Effective Wastewater Treat-
ment Systems, EPA-430/9-75-002 and Costs of Wastewater Treatment by
land Application provides construction grant applicants with informa-
tion for preliminary cost comparisons of various wastewater management
alternatives.
                             ACKNOWLEDGEMENT

This report was prepared by W. E. Gates and Associates, Inc.,
Fairfax, Virginia.

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                            TABLE OF CONTENTS


Section                                                     Page

  I       INTRODUCTION                                        1

 II       DESCRIPTION OF ALTERNATIVES                         2

III       DEVELOPMENT OF COST RELATIONSHIPS                   5
            Approach                                         5
            General  Cost Estimating Conditions                5
            Unit Treatment Processes                         6
            Transport Methodologies                          7
            Ultimate Disposal  Methodologies                  8
            Cost Relationships                               9

 IV      SLUDGE DISPOSAL COST CURVES                        11

  V      REFERENCES                                          12


                                 FIGURES

 No.

 1        Sludge Disposal Alternatives
 2       Sludge Disposal Cost  Curves

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                                SECTION I
                              INTRODUCTION
    The purpose of this report is to present a series of cost relationships
for sludge disposal alternatives and to describe briefly the process and
type of information used in creating the cost relationships.  In this context
the term "sludge disposal  alternative" is used to connote the combination
of sludge treatment processes and sludge transport and ultimate disposal
methodologies comprising a sludge management system.

    The basic premises or conditions selected for development of the cost
curves were as follows:

1.  The variables to be considered in the relationships were:
    a.    Sewage treatment plant flow rates varying from one to 1,000 MGD.
    b.    Two levels of treatment, primary and (activated sludge)  secondary.
    c.    Sludge treatment processes incorporating incineration and anaerobic
          digest ion.
    d.    Transport to ocean disposal by barging and to land disposal by
          truck, rail, and pipeline.
    e.    Land disposal by landfill   and land spreading.

2.  The range of transport distances for the ocean barging and land disposal
    methodologies were selected to reflect the transport distances likely
    to be considered by Eastern Seaboard cities, and were as follows:
    a.    Barge transport to ocean disposal locations at distances of 15,
          50, 80, 110, 150, and 180 miles from the barge loading station.
    b.    Land transport over distances of 20, 50, 100, and 150 miles.

3-  Barging transport costs were to be developed for two situations, viz,
    a.    "Simple" case, wherein all  sludge generated in a metropolitan
          area can be loaded at a single barge loading station.
    b.    "Complex" case,  where sludge is collected from a multiplicity
          of barge loading stations in a metropolitan area before the
          barge can be towed to sea.

4.  All cost relationships were to be developed using March 1975 costs.

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                                 SECTION  I I
                       DESCRIPTION OF ALTERNATIVES
    The sludge disposal alternatives for which cost relationships were
developed are shown  in  Figure  1.  The basic alternatives are as follows:

1.  Alternative  I:   vacuum filtration of primary and thickened biological
    sludges to produce  a sludge stream at 20% solids, followed by incineration
    and truck haul of the incinerator ash to a landfill site.

2.  Alternative  II:  digestion of primary and thickened biological sludges
    followed by  barging to an ocean disposal site under "simple" and "complex"
    barging conditions  as defined in Section I.

3.  Alternative  III:  digestion of primary and thickened biological
    sludges, vacuum  filtration of a portion of the digested sludge stream
    and blending of  this portion with undewatered digested sludge to
    produce a sludge at \0% solids, followed by barging to an ocean dis-
    posal site under "simple" and "complex" barging conditions.

k.  Alternative  IV:  digestion of primary and thickened biological sludge,
    followed by  tank truck or pipeline transport to a landspreading site.

5.  Alternative V:  digestion of primary and thickened biological  sludge,
    followed by vacuum  filtration to produce a sludge stream at 20% solids,
    and truck or rail transport to a landfill  site.

    Subalternatives were defined in each alternative to account for sludge
handling and disposal associated with primary and activated sludge secondary
treatment as follows:

1.  The secondary treatment suba1ternatives within each alternative were
    cost-evaluated as shown in Figure 1 and described above, i.e., inclusive
    of the biological sludge stream and the thickening unit process for
    this stream.

2.  The primary treatment subalternatives were cost-evaluated exclusive
    of the biological sludge streayn and the thickening unit process  for
    this stream.

    In developing material  balances for the sludge "flow" through  the
unit process trains  in each alternative,  the normalized parameter  selected
was "tons of dry solids per day per MGD of flow."  The values of this
parameter for the sludge stream at each point  in the unit process  trains,
and the corresponding solids concentrations of the sludge stream,  are shown
in Figure 1.  These data were developed using  the assumptions that:

1.  Primary treatment generates 0.5 ton dry solids/day/MGD at 5% solids
    in the sludge flow from the  primary  clarifiers.

2.  Secondary treatment generates 0.5 ton dry  solids/day/MGD at 5% solids
    in the sludge flow from the primary clarifiers and 0.25 ton dry  solids/
    day/MGD at 2% solids in the biological  sludge flow from the secondary
    clarif iers.

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FIGURE 1. SLUDGE DISPOSAL ALTERNATIVES
Primary_ Sludge Biological Sludge
[~0. 25 T
Notes:
1 . Units of "T" are:
Q J0 Tons dry sol ids per
L  day per MGD of raw
0.5 T @ 5% 1 DAF Thickening] sewage.

10.25 T
v M +
0.75 T @ 5%
i t
4
I VAC. FILTRATION! I DIGESTION |
1
0.71 T @ 20% '1*5 T @ ^
| INCINERATION |

r~ . r .
| PARTIAL VAC. F 1 LT|
0.21 T (Ash) 0.^5 T 1 	 -W'
@ W Bypass 0.^ T
r @ 10?
| TRUCK | BARGING BARGING TP

| LAN
LI

DFILL | OCEAN DISPOSAL! 1 OCEAN DISPOSAq | LP
1 1 III
@ 5% 2. Units of "I" are:
weight percent dry
sol ids.
i
VAC. FILTRATION)
0.45 T 0.1*3 T
T UCK OR PIPE- TRUCK OR RAIL
NE TRANSPORT TRANSPORT
i ' ^ r
NOSPREAD ING LANDFILL
IV V

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3.   Thickening by dissolved air flotation (DAF) increases the solids
    concentration in biological sludges from 2 to 5%.

*.   Incineration results in destruction of 70% of the dry solids content
    of the sludge flow.
5.  Digestion (anaerobic) results in destruction of kO% of the dry solids
    content of the sludge flow.

6.  Dewatering to 20% solids can be achieved with vacuum filtration.

7.  The maximum solids concentration of which sludge can be discharged
    (pumped) from a barge is 10%.

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                               SECTION  III

                    DEVELOPMENT OF COST RELATIONSHIPS


APPROACH
                                 X
    The steps used in the development of the cost estimates were as follows:

1.  Cost data were developed for each unit process, transport method, and
    ultimate disposal method specified in the sludge disposal alternatives
    presented in Figure 1, taking into consideration the variables of:
    a.   Plant flow rate  (1, 10, 100 and 1,000 mgd).
    b.   Type of treatment (primary and secondary).
    c.   Type of transport (truck, rail, pipeline, and barging) and one
         way transport distance (land, at 20, 50, 100, and 150 miles; and
         ocean,  at 15, 50, 80, 110, 150, and 180 miles).
    d.   Type of barging  (simple or complex).

2.  The above cost data were used in compiling costs by alternative for
    each combination of variables within each alternative, to obtain
    the desired  sludge disposal alternative cost data; because of the
    number of variables considered in each alternative, the sets of cost
    data developed in each alternative were as follows:
    a.   Alternative  I - 32
    b.   Alternative  I I- 96
    c.   Alternative 11 I- 96
    d.   Alternative  IV- 32
    e.   Alternative V - 32

3-  The selection of which transport mode was to be used in Alternatives
    IV and V (truck or pipeline in Alternative IV and truck or rail in
    Alternative  V) was based on least cost.

k.  The 288 sets of cost data obtained in the preceding steps were utilized
    in the development of a graphical  presentation of capital cost and
    total  annual (amortization plus operation/maintenance) costs as a
    function of  flow rate, treatment level, transport distance, etc., as
    the end product.

    The cost relationships developed in Step ^ above are presented and
described  in Section  IV, and the development of the cost data for the
individual unit  treatment processes and transport and ultimate disposal
cost relationships is presented below.


GENERAL COST ESTIMATING CONDITIONS

    The cost estimating conditions that were applied generally in the
development and/or updating of cost curves for individual  unit treatment
processes  and the transport and ultimate disposal methodologies are as
follows:

1.  Economic factors:

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2,000
2,500
3,000
3,500
1 ,000
1,500
2,000
2,500
500
1 ,000
1 ,000
1,000
500
1,000
1,000
1 ,000
    a.    Interest rate - 5 7/8% and project  life = 20 years, for which the
         value of the Present Worth Factor  is  11.59 and the value of the
         Capital Recovery Factor  is 0.0863.
    b.   Labor rate  (including fringe benefits) = $6.50 per man hour.
    c.   Service and  Interest Factor = 7.1%.
    d.   STP  Index  (Environmental Protection Agency) = 232.1 (March  1975).
    e.   Wholesale Price Index (Department of  Commerce) = 170.^ (March 1975)
    f.   CCI  (Engineering News Record) = 2200.

2.  Land Unit Costs:
    a.   Treatment plant sites:
               Q(MGD)           Land Cost  ($/Acre)

                 1                  3,000
                10                  *4,000
               100                  5,500
              1,000                  8,000
    b.   Landfill  or  landspreading sites:

               Q                Land Cost  ($/Acre) at Haul Distances of
              (MGD)             20 mi .   50 mj_.  100 mi.   150 mi.
                 1
                10
               100
              1 ,000

3.  Sludge generation quantities:  the assumption used is that  secondary
    treatment results in generation of 0.75 ton dry solids/day/MGD,  and
    primary treatment in 0.5 tons dry solids/day/MGD; thus for  any given
    flow rate, the sludge quantity generated for primary treatment is
    assumed to be equal  to two thirds of the quantities generated for
    secondary treatment.

    The additional assumptions, specific to cost evaluating each unit
process and sludge transport and disposal methodology, are discussed below.
UNIT TREATMENT PROCESSES

Dissolved Air Flotation

    Capital, 0/M and total annual costs for the DAF (dissolved air flotation)
thickening of biological sludges were estimated using cost relationships
developed by McMichael   (Reference l), updated to March 1975-   The para-
meters used in developing the DAF cost data were as follows:

1.  Dry solids loading  rate of kB Ib/day/sq ft.

2.  Polymer dose at 10  Ib/ton dry solids and polymer cost at  $1 per Ib.

Vacuum Fi1trat ion

    Estimates of capital, 0/M, and total annual costs for the vacuum
filtration process were developed using the following Bechtel cost rela-
tionships, updated to March 1975:

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1.  Alternative  I:  vacuum filtration of raw primary and biological sludge
    (Reference 2).

2.  Alternatives  II and V:  vacuum filtration of digested primary and
    biological sludge  (Reference 3).

Incinerat ion
    Estimates of capital, 0/M, and total annual costs for the  incineration
process were developed using Bechtel  cost relationships  (Reference k),
updated to March 1975-

Digestion

    Estimates of capital, 0/M, and total annual costs for the anaerobic
digestion process were developed using Bechtel cost relationships  (Re-
ference 5), updated to March 1975-
TRANSPORT METHODOLOGIES
P i peli ne

    Estimates of capital, 0/M, and total annual costs for pipeline trans-
port of sludge slurries were developed using cost relationships presented
by Thompson e_t^ a_l_ (Reference 6), updated to March 1975-  The updated
cost relationships were applied using the assumptions that:

1.   "Downtown" construction cost curves apply for pipeline installations
    from zero to 10 miles from the treatment plant.

2.   "Suburban" construction cost curves apply for pipeline installations
    between distances of 10 and 20 miles from the plant.

3.   "Rural" construction cost curves apply for pipeline installations at
    distances greater than 20 miles from the plant.

Truck and Ra i1
    The primary source of information used in developing truck and rail
haul total annual  cost curves were unpublished cost relationships developed
in the James River Comprehensive Water Quality Management Study (197' ~
1973), updated to March 1975.  These unpublished cost relationships were
developed by obtaining sludge haul bid costs from tank truck and rail
haul carriers as a function of wet tonnage hauled and haul  distance, and
were updated by direct contact with the haulers to obtain cost escalation
factors.

Barg ing

   Barging costs were developed using the barging economics model  developed
by Clark e_t^ aj_ (Reference 7).  The steps used in updating the parameters
in this model were as follows:

1.  Barging capacity was assumed to cost $3^0/ton (Reference 8), and towing

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    costs (at eight knots) were estimated as follows, using updates of
    data from References 9 and 10:

         Barge Capacity  (Tons)      Towing Cost  ($/hr)

                 8,000                    300
                 5,000                    225
                 2,000                    150

2.  Total annual barging cost curves were constructed as a function of
    annual wet tonnage hauled, barge size, and haul distance.

3.  From the above curves, the least total annual cost was defined as a
    function of annual tonnage and haul distance, and a second set of cost
    curves defining least annual  cost as a function of annual tonnage and
    haul distance were constructed.

1*.  The resultant cost curves were compared with cost projections for
    sludge barging (Reference 9)  from Philadelphia and DuPont (exemplary
    of the "simple" case) and New York (representative of the
    "complex" case).

5-  Excellent comparison was found between the Philadelphia cost projections
    and estimates for the Philadelphia and DuPont cases developed using
    the updated economic model; however, it was found that unit sludge
    barging costs  ($/wet ton) for New York were about twice those estimated
    using the updated economic model.

6.  Based on the preceding comparisons, two sets of barging cost curves
    were developed, one each for  the:
    a.   "Simple" case, using the cost curves constructed with the updated
         economic model.
    b.   "Complex" case, constructed by escalation of the cost  curves
         for the "simple" case by 1001.
ULTIMATE DISPOSAL METHODOLOGIES

Landfi11 ing

    Landfill capital, 0/M and total annual costs were estimated as follows:

1.  Landfill construction cost (excluding land) and 0/M costs were developed
    using cost relationships presented by Wyatt and White (Reference 11).
2.  Land costs were estimated using the unit land costs presented earlier
    in this section and a land requirement rate of 3-75 x 10   acre/ton
    of sludge (wet or dry)/year (Reference 12).
3.  Land costs were estimated to provide land for five years of operation,
    and no salvage value was assumed for the land.

Landspread ing

    Landspreading capital, 0/M, and total annual  costs were estimated as follows:


                                    8

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1.  An application rate of 10 tons dry solids/acre/year (Reference 13)-

2.  Distribution costs at $20/day/ton dry solids (Reference 1*0  and land
    preparation costs of $2,000/acre (Reference 12).

3.  The purchase and salvage value of the land required were assumed to
    be equal; the net annual cost of the land was estimated as equal to
    the annual interest cost on the purchase price of the land.
COST RELATIONSHIPS
    The initial objective in the assessment of the 288 sets of cost data
developed for Alternatives I  to V was to develop a single-page graphical
presentation allowing the user to:

1.  Estimate graphically the following types of costs, by alternative,
    type of treatment, flow rate, and type and distance of residuals
    transport:
    a.   Capital costs.
    b.   0/M costs, in units of cents per 1,000 gallons, and dollars per year.
    c.   Total  annual costs,  as the sum of amortization and 0/M costs,
         in units of cents per 1,000 gallons and dollars per year.

In the processes of evaluating the sets of cost data and exploring  ways
to develop the presentation,  it was observed that:

1.  Because of the lack of ready  information on capital costs for acquiring
    truck, rail, and barging systems, estimates could be obtained only
    for contract hauling (i.e., for total annual costs), and no breakdown
    could be developed for amortization and/or 0/M costs for these
    transport methodologies.

2.  While barging costs were found to be variable with respect to distance
    at a given flow rate and treatment level, such was not the case for
    the land disposal alternatives (Alternatives  I, IV, and V).  The
    total annual costs for Alternatives  I and V were found to be distance
    independent, and those for Alternative IV were found to vary +_ 20 percent
    at each haul distance with respect to the average value for all
    distances at a given flow rate and treatment  level.

3.  The latter circumstance, i.e.", the absence of a trend of increasing
    total annual cost with increasing land haul distance, at a given
    fTow  rate and treatment level, was fortuitous in that it reflects
    the values of unit land costs selected for the analysis (see subsection
    entitled GENERAL COST ESTIMATING CONDITIONS).

4.  That is, for the schedule of unit land costs selected for the evaluation,
    the sum of transport and land disposal costs on a total annual  basis
    was nearly equal at each haul distance, for all haul distances, in
    each land disposal based alternative at the same flow rate and  treatment
    level.

Because of the preceding circumstances,  it was necessary/possible to
adjust the framework of the graphical presentation as follows:

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1.   Capital costs are presented graphically only for the sludge processing
    and land disposal related elements of each alternative;  no capital
    costs are included in any alternative for the transport  element,  such
    that the capital  costs for each alternative are distance independent.

2.   Total  annual  costs for the land based alternatives are presented
    graphically for the sludge processing land disposal  related,  and
    transport elements on a distance independent basis.
                                    10

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                               SECTION IV
                       SLUDGE DISPOSAL COST CURVES
    A graphical presentation of the sludge disposal cost curves is presented
in Figure 2.  The elements of the cost curves are as follows:

1.  A flow rate scale ranging from 1  to 1,000 MGD.

2.  Capital cost scales for the primary and secondary treatment subalter-
    natives within each alternative,  wherein capital costs are included
    for the sludge processing and land disposal elements within each
    subalternative.

3.  Unit cost scales (in units of cents per 1,000 gallons) for each sub-
    alternative;  "unit cost" is defined as the normalized total annual
    cost, inclusive of amortization and 0/M costs, for the sludge processing,
    transport, and disposal elements  of each alternative.

k.  "Slant lines" for determining unit costs for barging disposal  at one
    way ocean haul distances of 15, 50, 80, 110, and 150 miles.

5-  A "slant" line for determining unit costs for the land disposal
    alternatives as a function of haul distances between 20 and 150 miles.

6.  A nomograph for determining total  annual cost (dollars per year) as  a
    function of flow rate and the unit cost for a given subalternative  at
    that flow rate.

    The procedure  for using the diagram is as follows:

1.  Select flow rate, treatment level, alternative, and haul  distance
    (haul distance If an ocean disposal alternative is selected).

2.  Enter flow rate on the "0_, MGD" scale in the upper left  hand  corner
    of th graph.

3-  Read capital  cost by moving rightward horizontally across the capital
    cost scales;  guide scales are provided at either side of  the  capital
    cost scales to assist *1ineup of the straight edge.

^4.  Read unit cost by reading horizontally from the "0_, MGD"  scale to
    the deflector  line;  proceed vertically downward to the appropriate
    slant line;  then read unit cost by moving rightward horizontally
    across the unit cost scales; guide scales are provided to assist lineup
    of the edge at each step.

5.  Using the selected flow rate,  the  unit cost as determined above,  and a
    straight edge, enter the "Nomograph for Determining Total Annual  Cost"
    and read total annual cost directly.
                                    11

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                                 SECTION  V
                                REFERENCES
1.  McMichael, W. F.  Cost of  Flotation  Thickening  of  Waste Activated
    Sludge.  U. S.  Environmental  Protection  Agency,  National  Environmental
    Protection Agency, Cincinnati, August  1972.

2.  Van Note, R.H.  e a_L              A Guide  to  the  Selection of Cost-
    Effective Wastewater Treatment Systems.   Prepared  by Bechtel  Corporation
    for U. S. Environmental Protection Agency,   EPA-430/9-75-002, July 1975,
    Page  11-44 and  Appendix B
3.  Van Note, R. H. et_ aj_.  Op_. cit.  Page  11-48 and Appendix B.

4.  Van Note, R. H. e_t^ aj_.  Q. c_i_t_.   Page  11-53 and Appendix B.

S.  Van Note, R.H.  et _]_.  Op., cit.   Page  11-38 and Appendix B.

6.  Thompson, T. L.  et_ a_K  Economics of Regional  Waste Transport and
    Disposal Systems.  Presented  at  the  Third Joint  AICHE-IMIQ Meeting,
    Denver, Colorado, September,  1970.

7-  Clark, B.D. e_t^  a_l_.  The Barged Ocean Disposal of Wastes.   A Review
    of Current Practice and Methods  of Evaluation.   U.  S.  Environmental
    Protection Agency, Pacific Northwest Water  Laboratory.   Pages 81-90.
    July,  1971.

8.  Wyatt, J.M. and P. E. White,  Jr.  A  Methodology  Guideline for the
    Ultimate Disposal of Solid Wastes.   Prepared by  Engineering-Science,
    Inc. for U. S.  Environmental  Protection  Agency.  Page VII-7-
    February, 1975.

9-  Mosser, William.  Personal communication.   April,  1975-

10. Economic Aspects of Ocean Activities.  Vol.  III.   Economic Aspects
    of Solid Waste  Disposal at Sea.  Massachusetts  Institute  of Technology.
    Appendix.  Pages IV-1 to 6.   March,  1970.

11. Wyatt, J. M. and P. E. White, Jr.  OJD. cit.  Figure Vlll-l.

12. Municipal Sewage Treatment:   A Comparison of Alternatives.  Prepared
    by Battelle Pacific Northwest Laboratories  Council  on Environmental
    Quality and Environmental Protection Agency,  1974.

13- Rutgers Symposium Reviews Land Disposal  of  Municipal  Effluents and
    Sludge.  Compost Science.  Vol.  14.  Page 26.   March,  1973-

14. Wyatt, J. M. and P. E. White, Jr.  0. cit.   Page VI11-40.
                                    13
                                                      *U.S. Government Printing Office: 1975-681-880/115

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