WATER POLLUTION CONTROL RESEARCH SERIES
11023 FIX 08/70
Conceptual Engineering Report
Kingman Lake Project
1/
U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER QUALITY ADMINISTRATION
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HATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the results and progress
in the control and abatement of pollution of our Nation's waters. They provide
a central source of information on the research, development and demonstration
activities of the Federal Water Quality Administration, Department of the
Interior, through in-house research and grants and contracts with the Federal,
State, and local agencies, research institutions, and industrial organizations.
Triplicate tear-out abstract cards are placed inside the back cover to facili-
tate information retrieval. Space is provided on the card for the user's
accession number and for additional key words. The abstracts utilize the
WRSIC system.
Water Pollution Control Research Reports will be distributed to requesters as
supplies permit. Requests should be sent to the Project Reports System,
Office of Research and Development, Department of the Interior, Federal Water
Quality Administration, Washington, D.C. 20242.
Previously issued reports on the Storm and Combined Sewer Pollution Control
Program:
11000
11020
11024
11023
11024
11023
11024
11034
11022
11020
11022
11023
11024
11024
11023
-— 01/70
FKI 01/70
D0K 02/70
FDD 03/70
DMS 05/70
EV0 06/70
— 06/70
FKL 07/70
DMU 07/70
— 08/70
DMU 08/70
FOB 09/70
FKJ 10/70
— 12/70
— 08/70
Storm and Combined Sewer Demonstration Projects -
January 1970
Dissolved Air Flotation Treatment of Combined Sewer
Overflows, (WP-20-17)
Proposed Combined Sewer Control by Electrode Potential
Rotary Vibratory Fine Screening of Combined Sewer
Overflows, (DAST-5)
Engineering Investigation of Sewer Overflow Problem -
Roanoke, Virginia
Microstraining and Disinfection of Combined Sewer
Overflows
Combined Sewer Overflow Abatement Technology
Storm Water Pollution from Urban Land Activity
Combined Sewer Regulator Overflow Facilities
Combined Sewer Overflow Seminar Papers
Combined Sewer Regulation and Management - A Manual
of Practi ce
Chemical Treatment of Combined Sewer Overflows
In-Sewer Fixed Screening of Combined Sewer Overflows
Urban Storm Runoff and Combined Sewer Overflow Pollution
Retention Basin Control of Combined Sewer Overflows
Continued on inside back cover....
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Conceptual Engineering Report - Kingman Lake Project
by
ROY F.WESTON, INC.
Environmental Scientists and Engineers
West Chester, Pennsylvania
for the
FEDERAL WATER QUALITY ADMINISTRATION
DEPARTMENT OF THE INTERIOR
Program No. 11023 FIX
Contract No. 14-12-829
August 1970
For sale by the Superintendent of Document!, U. S. Government Printing Office
Washington, D.C., 20402-Price $1.25
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FWQA Review Notice
This report has been reviewed by the Federal
Water Quality Administration and approved for
publication. Approval does not signify that the
contents necessarily reflect the views and
policies of the Federal Water Quality Admin-
istration, nor does mention of trade names or
commercial products constitute endorsement or
recommendation for use.
ii
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ABSTRACT
This conceptual engineering study concerns the reclamation of combined
sewer overflows and utilization of the reclaimed waters in a major water-
oriented recreational facility for the District of Columbia. The
investigation encompasses a comprehensive solution of environmental
problems by proposing multi-use objectives and facilities.
Principal objectives of the project included: 1) evaluation of rainfall
runoff relationships for sizing of storage and treatment plant capacities;
2) confirmation of treatment feasibility using filtration and an activated
carbon process; and 3) development of sufficient data for preliminary
design purposes.
Laboratory studies not only demonstrated process feasibility, but showed
the need for including flocculation and sedimentation for removal of
minute particles, together with chlorine and iodine addition for maximum
disinfection. The recommended storage/treatment plan provides for
a 175 million gallon storage basin, a 50 million-gallon-per-day reclamation
facility and two 46-acre swimming*and boating lakes.
Cost effectiveness (Cost/Benefit Ratio) of the project, as envisioned,
has been indicated to be 1.6 at an estimated total project cost of
$45,200,000, and an estimated annual operating cost of $1,777,000.
Implementation of the proposed plan would not only provide a least-cost
alternative over single-purpose projects to attain identical objectives,
but would also reduce the annual pollution now discharged by the North-
east Boundary Trunk Sewer by approximately 99 percent.
This report was submitted in fulfillment of Program No. 11023 FIX under
Contract No. 14-12-829 between the Federal Water Quality Adminstration
and Roy F. Weston, Inc.
Key Words: Activated carbon, adsorption, combined sewers, District of
Columbia, overflows, pollution abatement, precipitation (rain-
fall), recreation facilities, water storage, water reclamation.
iii
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CONTENTS
Section Page
ABSTRACT iii
CONTENTS v
FIGURES vii
TABLES ix
DRAWINGS xi
I CONCLUSIONS 1
II RECOMMENDATIONS 5
III INTRODUCTION 7
General 7
Project Objectives 7
IV COMBINED SEWER OVERFLOW PROBLEM 9
Data Needs 9
Drainage Basin Description 9
Description of the Northeast Boundary Trunk Sewer 9
Investigation of Rainfall-Runoff Relationship 13
V DEVELOPMENT OF ALTERNATIVES 29
Criteria for Development of Alternatives 29
Presentation of Alternatives 46
VI CONCEPTUAL ENGINEERING DESIGN 49
General Design Basis 49
Soils Investigation 50
Description of Proposed Facilities 55
VII COST ESTIMATES 85
Capital Costs 85
Operating Costs 88
VIII SELECTION AND COST EFFECTIVENESS OF
APPROPRIATE ALTERNATIVE 91
Selection of Storage Capacity and Reclamation
Plant Capacity 91
Cost Effectiveness of Project 91
Summary of Cost Effectiveness 95
IX ACKNOWLEDGMENTS 97
X REFERENCES 99
XI APPENDICES 101
v
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FIGURES
Figure No. Page
1 Hyetograph for Various Rainfall Frequencies 14
2 Standard Infiltration-Capacity Curves for 15
Pervious Surfaces
3 Determination of Infiltration Offset - 16
5-year Rainfall Frequency - Pervious
Residential Area
4 Determination of Point of Intersection 17
of Infiltration Capacity and Precipitation
Rate
5 24-Hour Overflow Volume versus Return 18
Frequency - Northeast Boundary Sewer
6 Rainfall Intensity-Duration-Frequency 20
Curves
7 24-Hour BOD Loading of Overflow versus 30
Probability of Being Equalled or Exceeded
Once in a Particular Year
vii
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
TABLES
Page
Zoning Classifications in Northeast Boundary 10
Trunk Sewer Drainage Basin
Major Components of the Northeast Boundary 12
Trunk Sewer
24-Hour Overflow Volume from Northeast 19
Boundary Sewer for Various Return Frequencies
and Total Rainfalls
Peak Flow Rates of Runoff from Northeast 21
Boundary Trunk Sewer
Comparison of Characteristics of Combined 23
Sewer Overflows and Storm Water Discharges
Precipitation Data, Washington International ie.4
Airport
Average Annual Waste Loadings of Combined 25
Sewer Overflow from Northeast Boundary Trunk
Sewer
Recommended Limitations on Waste Loadings to 26
Potomac River
BOD Loadings of Overflows from Northeast 27
Boundary Trunk Sewer
Annual and Impact Reduction in BOD for 32
Various Effective Storage Capacities and for
Storms with Various Return Frequencies
Recommended Water Quality Criteria for Fishing- 38
Boating Lake
Recommended Standards for Influent to Recreational 39
Lakes
Available Swimming Areas and Maximum Allowable 41
Number of Bathers for Various Design of Water
Reclamation Facility
Probability During August-October of Two or 43
More Storms Exceeding Reserve Storage
Capacity
Alternative Construction Costs 85
Summary of Project Costs 86
ix
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TABLES
(continued)
Table No. Page
17 Estimated Cost Summary - Tunnel Construction 87
for Surcharge Relief and Storage
18 Comparable Mined Storage Costs 88
19 Alternative Annual Operating Costs 88
20 Summary of Annual Operating Costs 89
175 mgd Storage and 50 mgd Treatment Facility
21 Cost Effectiveness of Kingman Lake Storage 91
and Treatment Alternatives
22 Construction Cost Estimates - Mined Storage vs. 93
Kingman Lake Storage and Treatment
23 Summary of Cost Effectiveness of Selected 96
Alternative
x
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DRAWINGS
Drawing No. Page
1 Northeast Boundary Sewer Drainage Basin 11
2 Water Reclamation and Recreation Facilities 56
3 Water Reclamation Facility - Plans and
Elevations 57
4 Water Reclamation and Storage Facilities 58
5 Water Reclamation Facility 59
10 Plot Plan 60
11 Schematic Flow Diagram 61
12 Hydraulic Profile 62
101 Detail Process Flow Diagram - Influent and
Storage Facilities 77
102 Detail Process Flow Diagram - Flocculation-
Sedimentation-Sludge Handling 78
103 Detail Process Flow Diagram - Multi-Media
Filtration 79
104 Detail Process Flow Diagram - Activated Carbon
Adsorbers 1 through 8 80
105 Detail Process Flow Diagram - Activated Carbon
Adsorbers 9 through 16 and Disinfection System 81
106 Detail Process Flow Diagram - Lake Area
Distribution and Recycle Systems 82
107 Detail Process Flow Diagram - Carbon Regeneration
System 83
xi
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SECTION I
CONCLUSIONS
It is the considered opinion of ROY F. WESTON that this project in its
entirety is both' technically and economically feasible. It is possible
for the Federal Government to demonstrate that wastewater and waste
land can be reclaimed for the use and advancement of society, and that
a total environmental approach to the problem of pollution can be ef-
fective.
Combined Sewer Overflow
1. The project conceived as a result of the study would be the largest
control and treatment works for combined sewer overflows in the
United States and would elevate the effluent quality above all other
existing or planned combined sewer overflow projects.
2. The Northeast Boundary Trunk Sewer serves approximately one third
of the combined sewer area of the District of Colvmibia.
3. The methodology developed for this study provides a reasonably ac-
curate' definition of the quantity, quality, and variability of
overflow from the Northeast Boundary Trunk Sewer.
4. The annual discharge of BOD5 in ;fche overflow from the Northeast
Boundary Trunk Sewer accounts for over 25 percent of the recommended
allowable waste loading to the Potomac River in the Washington metro-
politan area. Even the storm that is expected to occur with a fre-
quency of four times or more per year results in a BOD loading of
over twice the recommended allowable daily loading for discharges
from all waste treatment facilities in the metropolitan Washington
area. The recent Potomac Enforcement Conference held 21 and 22
Hay 1970 required that these recommended allowable loadings be
further reduced.
5. The impact of BOD loading in the overflow on dissolved oxygen levels
is more serious than the 25 percent value reflects, due to the com-
bined effect of long residence times of estuarine waters and the
true form of overflows occurring at discrete impact loadings.
Storage Alternatives
6. Storage is an essential element of any plan for the abatement of
pollution from the Northeast Boundary Trunk Sewer, because of the
extremely high overflow rates.
7. Locating a surface storage basin in the vicinity of Kingman Lake
is feasible and desirable since all overflow can be collected there
without extensive modifications and without pumping, and also
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because much of the area Is undeveloped, indicating the release of
open space for a storage basin is possible. The estimated cost for
surface storage was $14.3 million as compared to $33.4 million for
comparable mined storage.
8. Preliminary soils investigation indicates that the construction of a
storage basin in the lower section of Kingman Lake is technically
feasible.
9. The tunnel storage concept is applicable to the Northeast Boundary
Trunk Sewer and has the decided advantage of providing surcharge re-
lief of the existing sewer system.
Treatment Alternatives
10. Different levels of benefits are associated with each capacity of a
wastewater reclamation facility; these include allowable bather load,
probability of not overflowing the storage basin, and the additional
storage capacity provided by the plant's operating during the period
of the storm.
11. A literature evaluation disclosed that there are some promising al-
ternatives to those unit processes investigated in this study; how-
ever, confirmation work is necessary before any one can be applied
totally to the Kingman Lake Project. Included in this listing are
fiberglass filtration media and microstraining for suspended solids
removal, U-tube aerators for aeration, and ozonation for odor con-
trol and disinfection.
12. The use of iodine in conjunction with chlorine will provide effective
disinfection of viruses as well as bacteria in the swimming lake.
13. The use of chlorine in the swimming lake will prevent excessive algae
growth, but there may be an algae problem in the fishing-boating
lake, which does not otherwise require chlorination.
14. The recommended standards for the influent to the swimming lake are:
pH - 7.5 to 8.0; BOD - 5.0 mg/L; Suspended Solids - 15.0 mg/L; Total
Phosphorus - 0.05 to 1.0 mg/L; Free Chlorine - 1.0 mg/L; Free Iodine -
1.0 mg/L; Fecal Coliform - 200 per 100 ml.
Laboratory Investigative Program
15. Coagulation-Sedimentation followed by multi-media filtration, acti-
vated carbon adsorption, and disinfection will produce an effluent
which meets the water quality criteria objectives for swimming and
fishing.
16. Filtration through fiberglass was shown to be an effective method for
removal of suspended solids; however, significant development work is
required prior to any major facility application.
2
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Soils Investigation
17. Construction of a storage basin with vertical walls to a depth of
minus 40 feet is feasible.
18. Construction of a storage basin with sloping side walls is undesir-
able because of the restrictions on side slopes, the period of con-
struction, and the relatively small storage capacity available.
19. Construction cost estimates indicate that significant economics can
be effected through use of the slurry wall construction method
rather than the conventional approach using sheeting and bracing.
20. The foundations for all structures must extend to the sand and gra-
vel layer or to the underlying stiff clay. For shallow structures,
it will generally be most economic to provide pile foundations ex-
tending to these strata. The deep'er structures can be founded di-
rectly on the above-mentioned strata or may be constructed on pile
foundations.
21. Problems concerning general side grading, seepage, and other work
associated with raising the fisljing and swimming lakes to eleva-
tion +3.5 feet are not anticipated.
Selection of Alternative
22. The alternative scheme evaluated to have the highest cost effective-
ness encompasses a storage basin capacity of 175 million gallons and
a reclamation plant capacity of 50 million gallons per day.
23. The alternative scheme selected will provide:
a. Ninety-nine percent reduction of annual pollution load
from Northeast Boundary Trunk Sewer, eighty percent
reduction of pollution from a storm with a two-year
recurrence frequency, and sixty-one percent reduction
of pollution from a storm with a five-year recurrence
frequency.
b. Effective storage capacity to contain a storm with a
recurrence frequency of 1.2 years.
c. A ninety-six percent probability that the reclamation
facility will draw down the storage basin prior to
the recurrence of a second storm overflow (the volume
of which would exceed the remaining volume in the stor-
age basin).
d. Sufficient treatment plant capacity to support a maxi-
mum of 30,000 bathers per day in the swimming lake.
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24. The covering of the storage basin with a parking roof is justified
on the basis of comparable land acquisition and development costs
and estimated annual revenues.
25. The total project cost estimate of $45,200,000 compares extremely
well with benefits estimated at $72,755,000.
26. Operating costs are estimated to be $1,777,000 per year. Included
in the operating costs are: administration, labor, maintenance,
utilities, chemicals, make-up carbon, fuel oil, and an operating
contingency.
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SECTION II
RECOMMENDATIONS
1. Demonstrate hew the treatment of combined sewer overflows can serve
additional beneficial uses.
2. Demonstrate how the FEDERAL GOVERNMENT can approach the total solu-
tion to environmental problems.
3. Design and construct a 175,000,000-gallon storage facility, a
50,000,000-gallon per day water-reclamation facility, and the
associated swimming, boating, fishing, and parking facilities.
4. Continue to investigate and gather additional data to refine this
report and estimate prior to and during the engineering design and
construction phases of this project.
5. Provide sufficient space within the water-reclamation plant and
establish a field test facility to demonstrate new and promising
processes for improving the treatment of combined sewer overflows.
5
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SECTION III
INTRODUCTION
General
Recent efforts stimulated by the Federal Water Pollution Control Act,
as amended, have brought to light the significance of combined sewer
overflows as a source of pollution.
The overflows of combined sewers, however, involve other problems in
addition to pollution. Surcharging of existing sewers and the resul-
tant flooding of basements and underpasses are experienced in many
cities. This occurs primarily because increase in per capita water
usage, deterioration through age of existing sewer systems, and land
use changes have decreased the capacity of combined sewers to convey
storm water and have increased the proportion of rainfall that finds
its way into the sewers.
In the District of Columbia, an area of approximately 20 square miles
(one-third of the total area of the District) is served by combined
sewers. The hydraulic capacity of the system is often exceeded during
periods of precipitation, and raw sewage mixed with surface runoff is
discharged to the Potomac River and its tributaries. This adds signi-
ficantly to the polluted state of the Potomac River. An increased
concern for the enhancement of water quality has stimulated interest
in the abatement of pollution caused by combined sewer overflows; how-
ever, as brought out in a recent Federal Water Quality Administration-
sponsored study (1), the abatement of pollution from combined sewers
in Washington, D.C. will by no means be an inexpensive or expeditious
project.
Pollution of the streams in the District detracts from their aesthetic
values and prevents or interferes with intended water uses. The con-
dition of the streams, however, is only one element in the overall
environment. The social setting in Washington includes large numbers
of people, whose standard of living is well below the accepted minimum.
The proposed Comprehensive Plan (2) for Washington calls for creating
an environment "...which helps to compensate for some of the things
which deprived families are unable to provide for themselves". In
this perspective, the plan identifies a strong need for outdoor recrea-
tion facilities to serve the city's residents.
Project Objectives
The drainage basin of the Northeast Boundary Trunk Sewer accounts for
approximately one third of the area in Washington served by combined
sewers. The size of this drainage basin and the documented frequency
of overflow establish the significance of the pollution attributable
to this combined sewer. The combined sewer discharges to the Anacostia
River at a point just south of the Kingman Lake area, an arete recognized
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as having the potential to be developed as the city's major center for
outdoor recreation. As a result of the Department of Interior's interest
in abating pollution from this and other combined sewer overflow sources
and also of its recognition of a need for additional environmental and
recreational facilities for the people of Washington, D.C., the Federal
Water Quality Administration requested that ROY F. WESTON investigate the
feasibility of a multiple-purpose project combining the features of col-
lection and treatment of combined sewer overflows and recreational de-
velopment in the Kingman Lake area. The general scheme of the project
is the collection and storage of combined sewer overflows from the North-
east Boundary Trunk Sewer in the lower section of Kingman Lake, followed
by treatment of the overflows to a quality suitable for aquatic life
propagation and for public bathing in the middle and upper sections of
Kingman Lake.
Efforts of this investigation were directed generally towards the follow-
ing :
1. Definition of the quantity, quality, and variability of
combined sewer overflows from the Northeast Boundary
Trunk Sewer, and evaluation of flow and characteristics
data to determine required treatment and storage capa-
city.
2. Confirmation of the treatment method (high-rate filtra-
tion followed by activated carbon adsorption) previously
recommended in the preliminary report entitled "Kingman
Lake Recreational Area Project Presentation", prepared
by ROY F. WESTON, 14 August 1969.
3. Development of sufficient topographic survey and soils
information for use in preparing preliminary designs of
the storage lake, in establishing foundation conditions
for the treatment facility, and in determining the method
for replacement of the bottom and selected shore areas
of the upper section of the Lake with material suitable
for bathing purposes.
4. Firm establishment of a cost basis for a multiple-purpose
project to provide the needed recreational and pollution
abatement facilities and for comparison of the costs of
the proposed facilities with those of alternative projects
producing the same end results.
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SECTION IV
COMBINED SEWER OVERFLOW PROBLEM
Data Needs
The design of some of the facilities required in this project is depen-
dent to a large degree upon rainfall and the resulting runoff. More
specifically, the selection of the capacities of the storage facilities
and of the water reclamation plant must rest, in part, on the following
parameters: volume of overflow, peak flow rate, and contaminant load-
ings. Particular values of each of these parameters vary with each
storm, and it is necessary to perform a hydrologic analysis to define
the frequency and range of values. This type of information would pro-
vide a basis for evaluating the design alternatives. To perform a hy-
drologic analysis, extensive data are required concerning rainfall in-
tensities and frequencies, characteristics of the drainage basin and of
the existing sewer system, measurement of sewer flows, analysis of com-
bined sewer overflow for significant contaminants, etc.
Drainage Basin Description
The drainage basin of the Northeast Boundary Trunk Sewer (Washington, D.C.
Sewer District Number G-2), located in the northeastern portion of the
District of Columbia, is composed of 4,066 acres of predominantly resi-
dential land, but there is some commercial, industrial and park land.
In addition to the Northeast Boundary Trunk Sewer, several separate
storm sewers which serve a 350-acre area and discharge directly into
Kingman Lake must be considered in delineating the magnitude of the
overflow problem. Table 1 is a listing of the various zoning classifi-
cations in the drainage basin and the percentages of total area associ-
ated with each classification. The elevations of this basin range from
0 feet near the Anacostia River to 310 feet above mean sea level in the
northwestern portions (See Drawing No. 1). The basin generally drains
southeasterly and easterly to the Anacostia River.
Description of the Northeast Boundary Trunk Sewer
Sections of the Northeast Boundary Trunk Sewer were built at various
times between 1872 and 1939. Sewer configurations of the various com-
ponent sections include circular, rectangular, and elliptical. Table 2
is a description of the major component sections of the sewer.
Only about 15 percent of the Northeast Boundary Trunk Sewer has the hy-
draulic capacity to convey the sanitary sewage and storm water flow from
a 15-year return-frequency storm (3). Urban development since the ini-
tial construction period has been a major factor in increasing the quan-
tity of storm water which runs off and consequently is largely responsi-
ble for the present hydraulic capacity deficiency of most of the trunk
sewer. The District of Columbia, committed to relieving the surcharge
condition in the Northeast Boundary Sewer (with its resultant flooding
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Tab 1e 1
Zoning Classifications in Northeast Boundary
Trunk Sewer Drainage Basin
Percentage of
Type and Category Drainage Basin Area
Residential 69.1
R-l (one-family, detached) 1.9
R-2 (one-family, semi-detached) 1.3
R-3 (row) 3.6
R-i+ (row converted to apartments) kh.2
R-5 (general) 18.1
Commercial 5.5
C-l (neighborhood) 0.5
C-2 (community center) l+.l
C-3 (major center) 0.9
C-4 (central business district) 0.0
Manufacturing 13.1
C-M (light manufacturing) 9.5
M (general industry) 3.6
Park
12.3
Note: The zoning classification of the 350-acre area served by
storm sewers discharging directly to Kingman Lake is as
follows:
R-U
12$
R-5
16$
C-2
2$
Park
10$
10
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-an«COSt a »ivt»
1lM Si <«(•
LIMIT OF
p NORTHEAST BOUNDARY
N —.DRAINAGE AREA ,
UW(t ANA-COSTlA
main .•.rwctrto®
iiiiy.A'J
DISTRICT OF COLUMBIA
NORTHEAST BOUNDARY TRUNK SEWER DRAINAGE BASIN
-waTM *OUUTiOm
CONTROL WANT
LEGEND
— POLITICAL BOUNDARY
COMIINED SEWERS
SANITARY SEWERS
........ EXISTING sewers
^ LIMITS Of PRESENT COMUNEP
SEWER SYSTEMS
LIMITS Of SEPARATE
STORM SEWER AREA
1500 0 1500 3000 4500 6000
SCALE IN FEET
DRAWING NO. 1
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Table 2
N>
Major Components of the Northeast Boundary Trunk Sewer
Year(s) of Average
Locations Sewer Size(s) Construct ion Slope
New Hampshire Ave. and Park Rd.
to Euclid St. and Sherman Ave. 2l"0 to 1888-1892 0.0168
31-0" x V-6"
Euclid St. and Sherman Ave. to
Barry Place and 8th St. U'-O" x 6'-0" 1888 0.0372
Barry Place arid 8th St. to
Florida Ave. and 8th St. 6*f 1873 0.01^7
Florida Ave. and 8th St. to
Florida Ave. and 1st St. 6'-6" x 9,-9" 1885 0.0057
Florida Ave. and 1st St. to
Florida Ave. and 0 St. 10'^ 1885 0.0072
Florida Ave. and 0 St. to
Florida Ave. and 6th St. l6'-0" x 17'-6" 1886 O.OO38
Florida Ave. and 6th St. to
Florida Ave. and Maryland Ave. 20'^ 188I-I885 0.0022
Florida Ave. and Maryland Ave.
to 17th St. and E St. 22'0 l88l 0.0300
17th St. and E St. to 21st St.
and A St. 22'-0" x 23'-6" 1939 0.0057
21st St. and A St. to point
230 feet North of Massachusetts
Ave. Extended 22'-0" x 18'-3" 1935 0.0015
15'-6" x 8'-6"
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and restrictions on usage of many basement sanitary facilities), is cur-
rently considering the construction of a relief sewer in the area, at a
reported estimated cost of $33,000,000 (based on 1969 costs).
The existing system is designed to convey sanitary waste and some storm
water to the Blue Plains Treatment Plant by diverting the flow into the
East Side Interceptor at a diversion station on 21st Street between East
Capitol and A Streets. When the combined flow reaches a level of 9.5
feet (approximately 800 cfs), a sluice gate automatically closes, and
all flow is discharged directly into the Anacostia River. Previous stud-
ies performed for the D.C. Department of Sanitary Engineering indicate
that the average dry-weather flow in the Northeast Boundary Trunk Sewer
is 27.4 million gallons per day and that during a recent 12-month period
of normal rainfall this sewer overflows 57 times for an overall duration
of 300 hours (3,4).
Investigation of Rainfall-Runoff Relationship
Volume of Overflow - Methodology
»
The volume of surface runoff of rainfall into the Northeast Boundary
Trunk Sewer was calculated by subtracting the losses due to Infiltration
into pervious soils and retention in surface depressions from the total
amount of precipitation. An explanation of the methodology used for the
calculations of runoff is given in detail in Appendix D. In general,
the methodology included:
1. Construction of hyetographs for storms of various
frequencies (Figure 1).
2. Determinations of the relative percentages of pervious
and impervious areas of the basin.
3. Determination of the relationship of infiltration ca-
pacity to time (Figure 2).
4. Construction of "accumulated mass rainfall curves" and
"actual accumulated mass infiltration curves" and sub-
sequent determination of rainfall in excess of infil-
tration (Figures 3 and 4).
5. Determination of the volume of rainfall retained in
surface depressions.
6. Use of an area-depth correction factor to account for
application of point-rainfall data to the drainage
basin.
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0
Q
0
0
0
0
0
0
0
0
0
FIGURE 1
HYETOGRAPH FOR VARIOUS RAINFALL FREQUENCIES
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
TIME FROM BEGINNING OF SIGNIFICANT RAINFALL, MINUTES
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FIGURE 2
STANDARD INFILTRATION-CAPACITY CURVES FOR PERVIOUS SURFACES
SOURCE: DESIGN AND CONSTRUCTION OF time MINUTES
SANITARY AND STORM SEIERS
ASCE. NOP NO. 37, HE* YORK. I960.
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FIGURE 3
DETERMINATION OF INFILTRATION OFFSET
5-YEAR RAINFALL FREQUENCY
PERVIOUS RESIDENTIAL AREA
C_D
3.5
3. Q
S 2-0
0.0
40 150 160
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FIGURE 4
DETERMINATION OF POINT OF INTERSECTION
OF INFILTRATION CAPACITY AND PRECIPITATION RATE
5-YEAR RAINFALL FREQUENCY
PERVIOUS RESIDENTIAL AREA
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FIGURE 5
24-HOUR OVERFLOW VOLUME VERSUS RETURN FREQUENCY
NORTHEAST BOUNDARY SEWER
RETURN FREQUENCY, YEARS
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The calculated volume of runoff accounted for all runoff from pervious
areas during the period of the storm when rainfall was in excess of
infiltration capacity, and from impervious areas during the 24-hour
period of extreme rainfall as read from the updated Washington, D.C.
intensity-duration-frequency curves of Figure 5 (recorded values
1896-1897, 1899-1950, 1951-1969).
In addition to the Northeast Boundary Trunk Sewer, several separate
storm sewers (See Drawing No. 1) which discharge directly into Kingman
Lake must be considered in delineating the magnitude of the overflow
problem. Since diversion of these sewers will be required for the de-
velopment of Kingman Lake, the additional volume of runoff from these
sewers has been established by the above method and included in the
overall volume.
The total volume of overflow was determined by adding to the volume of
runoff the volume of sanitary sewage which overflows into the Anacostia
River when the sluice gates to the East Side Interceptor have closed.
However, during the detailed engineering design, consideration will be
given to installation of a controllable regulator to divert a portion
of the flow, rather completely cutting off the flow to the East Side
Interceptor.
Volume of Overflow - Results
The overflow volumes for a range of rainfall frequencies were determined
using the discussed methodology. The results are shown graphically in
Figure 6 and tabulated.with the associated 24-hour rainfall in Table 3.
Table 3
24-Hour Overflow Volume
from Northeast Boundary Sewer^-
for Various Return Frequencies and Total Rainfalls
Return Frequency 24-Hour Rainfall Volume of Overflow
3 months
2 years
5 years
15 years
25 years
1.1 Inches
3.3 inches
4.3 inches
5.5 Inches
6.0 inches
87 million gallons
275 million gallons
374 million gallons
486 million gallons
557 million gallons
-^Including small drainage basin adjacent to Kingman Lake.
Peak Flow Rates - Methodology
The rational method was utilized to determine the peak flow rate of run-
off for a range of rainfall frequencies. The values of the variables in
the rational equation were determined from information developed in pre-
vious studies as follows: Based on runoff coefficients used by the D.C.
Department of Sanitary Engineering for various zonings, an overall runoff
19
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FIGURE 6
RAINFALL INTENSITY-DU RATI ON-FREQUENCY CURVES
3
o
x
u>
hi
Z
o
z
<
u.
z
<
20.0
15.0
10.0
8.0
6.0
4.0
- 2.0
-------
coefficient of 0.72 was determined to be representative of the entire
drainage basin. An engineering study (3) on a proposed relief sewer
determined that the area of the drainage basin is 4,066 acres and that
the time of concentration is 52 minutes. The average intensity for the
52-minute period of extreme rainfall of each return frequency of interest
was determined from the intensity-duration-frequency curves utilized by
the D.C. Department of Sanitary Engineering (See Figure 6).
Peak Flow Rates - Results
Results of the peak runoff are listed in Table 4. These peak rates of
runoff are extremely high, and they would occur in the sewer only if the
hydraulic capacity of the Northeast Boundary Trunk Sewer was sufficient
to convey them. In actuality, the maximum hydraulic capacity of the
Northeast Boundary Trunk Sewer at the point of diversion to the three
overflow tubes is 3,320 cfs, which corresponds to the 0.6-year frequency
storm. Therefore, for the present design of the sewer system, the rela-
tive difference in peak runoff among the more intense storms is not
pertinent.
Table 4
Peak Flow Rates of Runoff from
Northeast Boundary Trunk Sewer
Return Frequency Average Intensity Peak Flow Rate
3 months 0.63 in./hr. 1,750 cfs
2 years 1.90 in./hr. 5,550 cfs
5 years 2.34 in./hr. 6,850 cfs
15 years 2.90 in./hr. 8,460 cfs
25 years 3.15 in./hr. 9,200 cfs
Combined Sewage Contaminant Loadings
The waste constituents in the overflow from the Northeast Boundary Trunk
Sewer have never been analyzed as part of any extensive monitoring pro-
gram; and quantitative sampling was not within the scope of this 21-week
study. However, overflows from other combined sewers and from some
separate sewers in the District have been monitored in previous stud-
ies (5). ROY F. WESTON operated monitoring systems on two combined
sewers and one separate storm sewer during a 6-month period in the spring
and summer of 1969. Flow measurements were made, and a considerable
number of the samples of dry-weather flow and storm flow were taken
and analyzed for a number of characteristics.
Several storms of varying intensities and durations were monitored in
that six-month period. The results showed that concentrations of waste
constituents vary considerably throughout the duration of runoff and
tend to Increase proportionally with the runoff flow rate during the
initial flushing period. The duration and intensity of the storm pro-
ducing the runoff had some effect on the concentrations. The observed
21
-------
range and mean value of each of the waste constituents of combined sewer
overflows and storm water discharges are presented in Table 5. The storms
from which the mean values were determined are representative of the
storms accounting for most of the annual rainfall, and the drainage
basins of the sewers monitored are very similar in development and
topography to the drainage basin of the Northeast Boundary Trunk Sewer.
Therefore, the mean values should be applicable to this study, but only
with careful interpretation.
The mean annual rainfall in the Washington, D.C. area, aa reported by
the U. S. Weather Bureau, is 40.8 inches (See Table 6). By comparing
the volume of overflow with total rainfall for the storm frequencies
analyzed, and by taking into account that 57.8 percent of the Northeast
Boundary Trunk Sewer drainage basin and 80 percent of the drainage
basin adjacent to Kingman Lake are impervious, it is reasonable to
assume that the annual volume of overflow is equal to 60 percent of
the annual rainfall. This suggests that the mean annual volume of
combined sewage overflow from the two drainage basins is approximately
3 billion gallons. The mean annual waste loadings of the combined sewer
overflow to the estuary were determined by applying the average waste
concentrations listed in Table 5. The annual waste loadings thus cal-
culated are presented in Table 7.
The Potomac Estuary is polluted and continues to experience problems with
low dissolved oxygen, excessive algal growths, sediments, and high con-
centrations of fecal bacteria. All of these problems are complicated by
combined sewers. Although combined sewer overflow adds to the sediment
load, the primary source of sediment is the heavy silt load included in
the runoff from areas with significant agricultural and construction ac-
tivity. The impact of combined sewer overflows is reflected in the prob-
lems of low dissolved oxygen and high concentrations of fecal bacteria,
and possibly in the excessive algal growth problem. To improve dissolved
oxygen levels, it was recommended by the conferees of the May 8, 1969
conference on pollution of the Potomac River that loadings from existing
waste treatment facilities discharging into the Potomac River between
River Mile 106 and River Mile 91 (Washington metropolitan area) be limited
to the values listed in Table 8. Comparison of the average annual waste
loading data of Table 7 with recommended annual load limitations developed
from Table 8 (by multiplying by 365) indicates that the Northeast Boundary
Trunk Sewer accounts for approximately 28 percent of the BOD, 9 percent
of the phosphorus, and 3 percent of the nitrogen, in the allowable limits
recommended for all wastewater treatment plant discharges in the area.
These percentage values are significant, and their impact is increased
by the circumstance that the discharges from the Northeast Boundary Trunk
Sewer occur as discrete shock loadings rather than as continuous discharges.
Consideration must also be given to the remaining combined sewer overflow
load and other storm water pollution loads from the District of Columbia
metropolitan area.
The latest Potomac Enforcement Conference conducted May 21 and 22, 1970
recommended that significantly higher standards be established for this
portion of the River, thus giving even more significance to pollution
emanating from combined sewer overflows.
22
-------
Table 5
Comparison of Characteristics of
Combined Sewer Overflows and
Storm Water Discharges
Waste Constituents
1
N>
U>
Chemical Oxygen Demand
Biochemical Oxygen Demand
Total Solids
Total Volatile Solids
Suspended Solids
Volatile Suspended Solids
Settleable Solids
Total Phosphate
Total Nitrogen
Orthophosphate
Ammonia Nitrogen
PH2
3
Total Coliform
Fecal Coliform"
Fecal Streptococcus*
Range
80 - 1,760
10 - 470
120 - 2,900
40 - 1,500
35 - 2,000
10 - 1,280
0 - 1,308
0.8 - 9.4
1.0 - 16.5
0.1 - 5.0
0 - 4.7
5.6 - 6.7
420,000 - 5,800,000
240,000 - 5,040,000
1,000 - 49,000
Combined Sewage
Separate Storm Flow
Mean
382
71
883
344
622
245
229
3.0
3.5
2.0
1.5
6.3
2,800,000
2,400,000
17,200
Range
1,514
90
29
3
338 - 14,600
12 - 1,004
130 - 11,280
0 - 880
0 - 7,640
0.2 - 4.5
0.5 - 6.5
7.2 - 6.0
120,000 - 3,200,000
40,000 - 1,300,000
3,000 60,000
Mean
335/,
19
2,166
302
1,697
145
687
1.3
2.1
6.5
600,000
310,000
21,000
1
3
mg/L unless otherwise noted.
'pH units.
Counts per 100 ml.
^Excluding sample from June 8 storm, which had a BOD concentration of 660 mg/L.
-------
Table 6
Precipitation Data
Washington National Airport
Washington, D.C.
Prec ip i tat ion
Month
Normal
Monthly Total
i nches
Maximum
in 2lj—hours
i nches
Year of
Occurrence
January
3.05
1.73
19^8
February
2.U7
1.63
1961
March
3.21
3-^3
1958
April
3.15
1.77
19^8
May
U.lU
M2
1953
June
3.21
3.67
191+7
July
k.13
2.97
1952
August
b.90
6.39
1955
September
3-83
1+.15
1966
October
3.07
M8
1955
November
2.81+
2.60
1963
December
2.78
1.85
1951
TOTAL ANNUAL
i+O.78
Source: Local CIimatological Data. Annual Summary with
Comparative Data, 1968. Washington, D.C. U.S.
Department of Commerce, ESSA.
24
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Table J
Average Annual Waste Loadings of Combined Sewer
Overflow from Northeast Boundary Trunk Sewer1
Pol 1utants
Chemical Oxygen Demand
Biochemical Oxygen Demand
Total Sol ids
Total Volatile Solids
Suspended Solids
Volatile Suspended Solids
Settleable Sol ids
Total Phosphate
Total Nitrogen
Orthophosphate
Ammonia Nitrogeh
Pollutant Loading
million pounds/year
9.6
1.7
22.1
8.6
15.6
6.1
5.7
0.075
0.088
0.050
0.038
Recommended
Standards2
million pounds/year
6.02
0.88
2.9
¦"¦Including small drainage basin adjacent to Kingman Lake.
Calculated from Table 8.
25
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Table 8
Recommended Limitations on Waste Loadings
to Potomac River
lbs/day
Facility
bod*
Total
Phosphorus
Total
Nitrogen
Pentagon
Arlington
District of Columbia
Alexandria
Fairfax Westgate
300
20
60
560
60
40
145
650
6,130
630
445
1,300
12,700
1,300
900
16,500
740
8,000
Source: "Proceedings-Third Session of Conference in the Matter of Pollu-
tion of the Interstate Waters of the Potomac River, April 2-4,
May 8, 1969, Washington, D.C.", FWQA.
It is of special interest to define the magnitude and variability of BOD
loadings of the overflow from the Northeast Boundary Trunk Sewer. Table 5
indicates that the concentration of the BOD in combined sewage ranges
from 10 mg/L to 470 mg/L and has a mean of 71 mg/L. The sources of BOD
in combined sewer overflow are the organic wastes contained in storm
runoff from the urban area, the sanitary sewage mixed with the runoff,
and the initial flushing action on the ground surface and in the catch
basins and sewers.
Sufficient information is available from the previous ROY F. WESTON study
to identify the relative significance of these sources for several storms.
If the runoff has a BOD concentration of 19 mg/L, and the duration and
time of the storm are correlated with the diurnal characteristics of the
dry-weather flow in the sampled sewer, the BOD loadings due to runoff
and sanitary sewage can be accounted for. The effect of flushing accounts
for the remaining BOD, and it can be correlated to drainage area (imply-
ing a specific length of sewer lines) and to the length of dry-weather
period between storms. For average dry-weather conditions, the data de-
veloped in the previous study indicated that the flushing action results
in a BOD loading of 3 pounds per acre of drainage area.
These values provide a basis for determining the BOD loading of the
overflow from the Northeast Boundary Trunk Sewer for a range of rain-
fall frequencies. The BOD concentration of the runoff is assumed to
be the 19 mg/L as indicated in the earlier WESTON study, the BOD con-
centration of sanitary sewage is assumed to be the typical value of
200 mg/L, and the BOD loading due to flushing is assumed to be 3 lbs/acre
as determined for similar basins. The results are listed in Table 9.
26
-------
Table 9
BOD Loadings of Overflows from
Northeast Boundary Trunk Sewer"'"
Rainfall Frequency
BOD Loading
3 months
2 years
5 years
15 years
25 years
35,600 pounds
72,700 pounds
88,400 pounds
106,000 pounds
117,400 pounds
"'"Including small drainage basin adjacent to
Kingman Lake.
From this table (which includes the effects of the small drainage basin
adjacent to Kingman Lake) and related flow data, the mean BOD concentra-
tion of the overflow from the 3-month storm is calculated to be 50 mg/L,
which compares favorably with the reported mean of 71 mg/L of BOD for
the combined sewer overflow sampled in the previous study. Note that
even the 3-month storm results in a BOD loading of over twice the rec-
ommended daily loading for discharges from all waste treatment facilities
in the Washington, D.C. area.
The methodology of separately accounting for the three sources of BOD in
combined sewer overflow can be extended to determine annual BOD loading.
With this method, the annual BOD loading is 1.6 million pounds, which
checks very closely with the 1.7 million pounds determined by simply mul-
tiplying annual overflow volume by the mean BOD concentration (in com-
bined sewer overflow) of 71 mg/L.
The maximum precipitation in the Washington area for a 24-hour period was
7.31 inches and occurred on August 11-12, 1938 (6). It is estimated by
graphical interpretation that such a storm would result in an overflow of
680 million gallons. The maximum precipitation for a 48-hour period and
for a 72-hour period are the same, 8.67 inches, and also occurred in
August 11-12, 1938. The additional rainfall of 1.36 inches would have
resulted in an additional overflow of approximately 120 million gallons.
Thus, during the three-day period of maximum precipitation, approximately
800 million gallons are estimated to have overflowed from the combined
sewers.
Verification of Results
As previously stated, the volume of overflow and concentration of pollu-
tants in the overflow from the Northeast Boundary Trunk Sewer have never
actually been measured as part of an extensive sampling and monitoring
program; therefore, it was not possible to verify the results of this
study with past observations of the actual area. In developing data con-
cerning the combined sewer overflow certain phenomena, e.g. infiltration
27
-------
and surface depression storage, were applied to the Northeast Boundary
Trunk Sewer drainage basin even though they were based on observations
made for other drainage basins, both in Washington, D.C. and other cities.
These applications are reasonable, and the possibility for significant
errors in the results appears to be remote. For example, if the differ-
ence between the actual infiltration capacity and the assumed infiltration
capacity is as much as 33 percent, the change in total volume of overflow
is only about 15 million gallons for the 2-year storm and 30 million gal-
lons for the 25-year storm. The error associated with a 33 percent differ-
ence in volume of surface depression is only about 3 million gallons.
It should be noted that, as a part of this study, an indicating-recording
liquid-level gauge has been installed by ROY F. WESTON, with the assistance
of the D.C. Department of Sanitary Engineering, near the point of overflow
in the Northeast Boundary Trunk Sewer, and future readings from this gauge
should provide some basis for verification of the calculated results.
Also, during the performance of this study ROY F. WESTON provided infor-
mation concerning hydraulic characteristics of the sewer, the drainage
basin, rainfall, etc. to Metcalf and Eddy Engineers, Water Resources
Engineers, and the University of Florida, who have been retained by the
FWQA to apply a mathematical model to the Northeast Boundary Trunk Sewer.
The results of this mathematical simulation study should provide infor-
mation concerning overflow and pollutant concentrations and verification
of suspected surcharge areas for various storm events. The mathematical
model should also be able to predict the impact of the Northeast Boundary
Trunk Sewer overflow on the water quality of the Potomac Estuary.
28
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SECTION V
DEVELOPMENT OF ALTERNATIVES
Criteria for Development of Alternatives
The problem definition phase of this study has defined the frequency and
range of values of the principal design parameters. From this, it is
possible to develop numerous alternative strategies for collecting, stor-
ing, and treating overflow, each alternative providing a different level
of benefits in such areas as enhancement of water quality, increase in
the number of bathers allowed at a swimming facility, decrease in fre-
quency of surcharging of sewers, more parking space, etc.
To provide a sound basis for decision making, it is necessary to develop
a sufficient number of promising alternatives to offer a wide and rea-
sonable choice, and then to define consequences of each in detailed and
comparative terms so that cost-benefit relationships can be identified
and evaluated.
Impact on Water Quality
The problem of low dissolved oxygen levels in the Potomac is interstate
in scope, and requires a regional approach to any solution. The impact
and risk of various BOD loadings from combined sewer overflows must be
evaluated not just as an annual or average daily loading, but also in
its true form as shock loadings. This form, combined with the long
residence times of estuarine waters, explains the particularly serious
impact combined sewer overflows have on water quality.
Storage is an essential element of any plan for the abatement of pol-
lution from the Northeast Boundary Trunk Sewer. Since any retained
overflow is to be treated, the quantity of collected overflow represents
a practical measurement of the reduction in pollution. Figure 7 illus-
trates, for a range of storage capacities, the 24-hour BOD loadings
versus the probability of being equalled or exceeded once in a particu-
lar year. Since the overflow is to be collected over a 24-hour period,
the term "effective storage capacity" has been selected to denote the
total of the capacity of the storage basin plus one day's capacity of
the water reclamation facility. In making these calculations, it was
assumed the percentage reduction in BOD is equal to the percentage of
the total overflow collected.
To illustrate, the bar in Figure 7 represents the consequences of a
5-year frequency storm. With no storage (i.e., no collection of com-
bined sewer overflow) this storm would generate a 24-hour BOD loading
to the surface waters equal to or exceeding 90,000 pounds. In contrast,
with an effective storage capacity of 200,000,000 gallons, the 5-year
storm would result in a 24-hour BOD loading to the rivers of 42,000
pounds or more. Whereas the overall reduction in organic pollution
from this 5-year frequency storm would be approximately 50,000 pounds
29
-------
FIGURE 7
24 HR. BOD LOADING OF OVERFLOW
VERSUS
PROBABILITY OF BEING EQUALED OR EXCEEDED ONCE IN A PARTICULAR YEAR
30
-------
(or 56 percent of the storm loading), the amount of organics which would
be bypassed is two and a half times the maximum allowable daily loading
recommended for all discharges in the area.
Since the reduction in pollution is effected by collection of storm and
combined sewer overflows and subsequent treatment, the degree of reduc-
tion of all constituents (including BOD) can be estimated with reasonable
accuracy as a function of the volume of wastewater collected.
The annual BOD loading associated with any given storage capacity can
be determined from Figure 7 by either of two methods:
Method A
1. Convert the appropriate cumulative distribution function
(curve) in Figure 7 to reflect less than or equal prob-
abilities, rather than the greater than or equal proba-
bilities depicted.
2. Develop a probability function from the new cumulative
distribution function.
3. Integrate the following formula
E(x) = /0" x f(x) dx
where:
E(x) = expected annual BOD loading
x = BOD loading from storm
f(x) « probability function
Method B
1. Plot the appropriate cumulative distribution function
(curve) in Figure 7 on arithmetic graph paper.
2. Determine the area beneath this curve.
3. This area is equal to x-f(x), or the expected annual
loading of BOD.
Table 10 illustrates the overall annual reduction in organic pollution
which would be obtained for various effective storage capacities and
the percentage reduction in impact pollution loading for single occur-
rences of storms of various frequencies. For example, an effective
storage capacity equal to the overflow from a one-year storm (225 mil-
lion gallons) reduces the expected annual BOD loading by 99 percent
(from 1,700,000 pounds to 26,000 pounds).
31
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Table 10
Annual and Impact Reduction in BOD
for Various Effective Storage Capacities and for
Storms with Various Return Frequencies
0
Effective Storage Capacity in
mi 11 ions of gal Ions
~w
115
221
285
w
Annua] Reduction in
Pollutant Loading
0
96$
99#
99+#
99+#
99+9
Impact Reduction for
Single Storm Occurrence
3-Mo. Storm
0
100#
100#
100#
100#
100#
1-Yr. Storm
0
100#
100#
100#
100#
2-Yr. Storm
0
39#
80#
100#
100#
100#
5-Yr. Storm
0
31#
61#
73#
100#
100#
15-Yr. Storm
0
2|#
lj-6#
56#
78#
100#
Extent of Recommended* Allowable
Load Remaining
After 3-Mo. Storm
216#
0
0
0
0
0
After 1-Yr. Storm
3^6#
176#
0
0
0
0
After 2-Yr. Storm
^32#
289#
0
0
0
After 5-Yr. Storm
^5#
376#
218#
1^5#
0
0
After 15-Yr. Storm
65U#
50
352#
291#
1^5#
0
Average Number of Overflows per Year
_ —
3-3
1
0.5
0.2
0.07
*Recommended daily loadings for Potomac River between River Mile 91 and River Mile 106
by the conferees of the 1969 Conference on Pollution of the Potomac River. See Table 8
-------
The number of overflows from the Northeast Boundary Trunk Sewer into
the Anacostia River has been estimated to be approximately 60 per year.
Table 10 also indicates the average number of overflows to the river
which would be expected with various effective storage capacities.
Wastewater Storage Considerations
A shortage of land as well as a common objective to enhance the beauty
of Washington limit the application of surface storage. An exposed,
open-storage structure is hardly acceptable in the established, low-
density residential areas. Nor would it be consistent to displace
low-income families residing in areas programmed for rehabilitation
when a critical shortage of low-cost housing already exists and racial
barriers interfere many times with relocating in adjacent suburbs.
Also, Washington has the image of being a city of parks, and its com-
prehensive plan provides that this system of open space be extended
and elaborated even further. Although an uncovered or exposed struc-
ture is generally unacceptable, the use of subsurface space just below
open areas is promising, especially if the cover over the storage
structure has a joint purpose, e.g. parking, recreation, etc.
Engineering considerations involved in locating storage facilities are
soil characteristics and the requirements for collection of combined
sewer overflows. It is desirable that a facility be located at such
an elevation to permit collection of combined sewer overflow by gra-
vity; otherwise, matching the peak overflow rate would demand excep-
tionally large pumping capacity. It is also desirable to locate storage
facilities in the vicinity of the point of overflow to avoid both ex-
tensive modification to the sewer and the construction of a lengthy
diversion sewer. Soil characteristics are, of course, a prime consid-
eration, because the very large volume of overflow to be dealt with
identifies the significant hydrostatic pressure to be encountered and
the foundation needs for the large structure required.
Surface Storage in the Vicinity of Kingman Lake
Surface storage in the vicinity of Kingman Lake is attractive for the
following reasons:
1. Since the only point of overflow from the Northeast
Boundary Trunk Sewer is near this area, all overflow
may be collected without extensive modifications or
construction of a lengthy diversion sewer.
2. The differential elevation between the point of diver-
sion and the immediate Kingman Lake area would permit
gravity flow from the Northeast Boundary Trunk Sewer to
any location likely to be selected for the storage basin.
3. Much of the area is undeveloped, indicating that the
release of open space for a storage basin is possible,
33
-------
especially since the construction of the basin could
be coordinated with future development of recreational
facilities and thus provide proper architectural iden-
tity and serve other aesthetic purposes.
After consultation with the many and varied agencies which have an in-
terest in the recreational center or in any other facility existing or
proposed in the area, it was agreed that the section of Kingman Lake
south of the East Capitol Street Bridge should be investigated as a
possible location for storage. Possible disadvantages of this
particular area are:
1. Prior investigations in the Kingman Lake area have
identified the presence of soft and compressible
solid strata.
2. The Anacostia River is close, and periodic flooding
of the area has occurred in the past.
3. The proposed eight-lane East Leg Freeway will re-
quire significant area, and its structural require-
ments must be considered in any plan.
To secure sufficient solids information about the site, the firm of
Joseph S. Ward and Associates was retained to perform a soils investiga-
tion. The report of this study is submitted, as a separate volume, as
Appendix C. Significant findings excerpted from the Ward report have
been included in various sections of this main report.
A relevant conclusion from Ward's study is that although the upper
soils strata are not suitable for the founding of structures, an
underlying stiff clay can provide good foundation support. The depth
of any storage basin at this site is defined by the requirements to
excavate to an elevation of -40 feet (the clay zone), and by the require-
ment that the maximum water level be limited to -5 feet elevation to
prevent hydraulic uplift pressures on the adjacent highway slab. The
surface area of the storage basin is limited by the need to stay within
the boundary of the Anacostia River, the East Capitol Street Bridge, and
the western edge of the proposed East Leg Freeway. Also limiting are
the requirements that any proposed water reclamation facility must be
set back from both the existing sea wall and the proposed flood dike
along the Anacostia River. Within these limits, any number of different
size storage basins can be constructed; the actual size depends on how
much of the space below the proposed eight-lane highway is used, how
much space is allotted for the water reclamation facility, what the
setback is from the river, and at what level the cover of the basin is
placed. If the flood dike is constructed east of the existing sea wall,
34
-------
the maximum capacity basin that can be constructed is 235 million
gallons; a practical minimum is 90 million gallons, and any capacity
between these is possible.
Tunnel Storage
The concept of tunnel storage is similar to that of a storage reservoir,
i.e. sufficient storage for the sewer overflows, with provision to pump
the stored wastewater back into the regular setoers for conveyance to a
treatment plant when the storm subsides. This approach also requires
adequate sizing of inlet structures for the storage tunnels to eliminate
the existing surcharge conditions in the main sewer lines. Under this
alternative, storage would be in large-diameter tunnels rather than in
shallow underground reservoirs. Recent developments in the tunnel con-
struction and tunneling equipment fields enhance the feasibility of this
approach, particularly in regard to available maximum tunnel diameters.
Tunnel storage has the advantages (over surface storage) of less land
requirement, lesS public inconvenience, greater reliability, and more
flexibility, as discussed in a previous report (1). A decided advantage
(over a single storage reservoir at the end of the sewer) is the capa-
bility tunnel storage has for providing surcharge relief of the total
sewer system. This is accomplished by locating vertical shafts in the
sewer system at various points to intercept flows and provide surcharge
relief along critical sections of the sewer. This dual application is
especially significant in view of current District of Columbia plans to
construct a relief sewer in the Northeast Boundary Trunk Sewer Area at
an estimated cost of $33,000,000 (1969 cost). Attached as Appendix B
is a discussion of the application of tunnel storage to the Northeast
Boundary Trunk Sewer, its cost, and the geological investigative program
required to provide the information necessary for design.
Water Quality Requirements
Water quality standards for swimming and activities such as boating and
aquatic life propagation have been established by various agencies; how-
ever, a project such as the Kingman Lake Project was not anticipated
when these standards were established. Public acceptance as well as
public health are of concern, and existing criteria may have to be sup-
plemented by additional assurance before they can be applied to this
project. In a communication dated 17 December 1970, Mr. John Brink
of the District of Columbia Department of Public Health stated
"Specifically, the facilities proposed for treating combined sewage
must be 'fail-safe' and able to consistently produce water of drinking
quality."
Several projects, including the South Lake Tahoe Sewage Treatment
Plant and the Santee Recreation Project, have demonstrated that these
rigid standards can be attained.
Of special interest is the experience obtained in operating the Santee
Recreation Project in Santee, California, as reported in a recent pub-
lication (7). The Santee Project demonstrated that public acceptance of
35
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the reuse of wastewater for fishing and swimming is possible; however,
extensive and deliberate measures were taken by several agencies to
support that project and to promote public approval. Unless similar
measures are taken for the Kingman Lake Project, social stigma may act
to block the achievement of the social goals of the project.
Swimming Lake Water Quality
Swimming is a primary water contact recreation activity in which there
is prolonged and intimate contact with the water. Public health is of
paramount concern, and water quality standards generally reflect both the
considerable risk involved of ingesting contaminated water and the docu-
mented possibility of disease transmittance. In this sense, viral and
bacterial levels are a primary concern. The District of Columbia Depart-
ment of Public Health's bacteriological criterion for water contact rec-
reation is that fecal coliform are not to exceed 200/100 ml. The depart-
ment has not established standards for viruses.
Even though the source of water for the swimming lake is highly contam-
inated, this is not a disqualifying condition, because the water can be
treated to a quality level suitable for swimming. Actually, the primary
source of contamination is that introduced by the swimmer himself.
Chlorination is an effective disinfectant for swimming pools, but its
effectiveness in large bodies of water is uncertain. A free chlorine
residual is necessary to assure effective destruction of viruses as well
as of bacteria, but chlorine is a strong oxidizing agent and reacts with
substances introduced by bathers, e.g. ammonia. These reactions shift
the concentration of chlorine from a free residual to a combined residual
which is ineffective against viruses. Use of chlorine is satisfactory
if distribution of free chlorine is achieved by effective turnover of the
swimming water; however, effective turnover is difficult to achieve in
large bodies of water, and isolated stagnant pockets of water containing
no free chlorine residual may develop. Another disadvantage of chlorina-
tion is that it requires maintenance of pH below 7.4 in order to prevent
significant dissociation of the hypochlorous acid into components which
have far less disinfectant power; unfortunately, water with a pH lower
than 7.4 is conducive to eye irritations.
Recent research (8, 9, 10) has indicated that iodine in conjunction with
chlorine may overcome the limitations previously discussed. Both iodine
and a product of its hydrolysis, hypoiodous acid, possess excellent
germicidal properties against pathogenic bacteria and viruses. Iodine
has a lower oxidization potential than chlorine, and consequently does
not react as readily with organic and .other oxidizable matter encountered
in bathing water. Therefore, residuals of free iodine persist much
longer than free chlorine residuals. In the presence of stronger
oxidants, reduced iodide ions resulting from any reactions between iodine
and pxidizable matter are re-oxidized to the original effective form by
the oxidant. Chloramine, the most common form of combined chlorine, is
a strong oxidizing agent and is capable of oxidizing reduced iodide ions.
Objectionable colors and odors associated with some chemical forms of
36
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iodine are avoided by maintaining a pH range of 7.5-8.0, which is above
the eye irritation range and at a level where the dissociation of
hypoiodous acid is negligible.
These observations suggest the use of iodine and chlorine will maintain
viricidal and bactericidal agents at a concentration sufficient to
assure that disinfection is an immediate and continual process through-
out the swimming area, even in isolated stagnant pockets. An extensive
monitoring and control system should be established to detect the
residual disinfectant levels and to regulate the flow of disinfected
water to specific areas where residuals drop below predetermined levels.
Observations by public health authorities generally agree that water
turnover period should be no longer than 12 hours (and preferably limited
to 6-8 hours) to maintain sanitary conditions in swimming water disin-
fected by chlorine. Turnover periods required for water disinfected by
iodine have not yet been developed; however, on the basis of the foregoing
discussion of the greater persistence of free iodine residuals, the
minimum turnover periods required for iodine-disinfected water should
be longer. The turnover proposed for this project is 8 hours.
Few people will swim in water containing floating or suspended solids or
objectionable color or odors, especially if the source of the swimming
water is known by the public to be polluted. Although turbidity and
color problems were experienced in the Santee Project, public acceptance
of the swimming facility was still good. Even so, the opportunity for
public acceptance would be enhanced if the water is free of turbidity
and color. This suggests that consideration must also be given to 1)
nutrient concentrations and their effect on seasonal blooms of algae;
2) turbidity levels associated with different types of bottom material;
and 3) other factors which may not be related to health but add to or
detract from the enjoyment of swimming.
Boating-Fishing Lake Water Quality
In contrast to swimming, contact with water during boating and fishing
activities is incidental, and bacteriological standards are far less
stringent. The D.C. Department of Health's criteria for fishing and
boating are a geometric mean fecal coliform count of not more that 1,000/
100 ml and a limit of 2,000/100 ml in no more than 10 percent of the
samples.
Of more concern is the transmittance of harmful bacteria and viruses to
individuals eating fish caught from the lake. After two years of study,
the public was permitted to eat the fish caught from the Santee Lake.
Extensive study never isolated any viruses in either fish or algae.
The concentration of coliform in the intestinal tract content of fish
was slightly higher than for fish obtained from fresh water lakes, but
it was felt that this did not prohibit human consumption because bacteria
did not reach the edible flesh of the fish.
37
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Water quality criteria are well established for varying species of fish
and other aquatic life, and the criteria obviously vary with the type of
aquatic life desired. The water quality aspects, other than bacteria
and viruses, of concern in this project are dissolved oxygen, temperature,
pH, alkalinity, turbidity, settleable material, and nuisance plant nu-
trients . The level at which these are present in a fresh water environ-
ment almost totally determines the biotic response. To assure the spawn-
ing, egg development, and growth of such warm-water fish species as large-
mouth bass and bluegill (commonly stocked species for fishing lakes in
the Middle Atlantic), the criteria listed in Table 11 are recommended (11).
Certain criteria concerning toxic chemicals, heavy metals, oil, color,
dissolved solids, and tainting substances can be maintained if a minimum
degree of control is placed on industrial and commerical activities in
the drainage basin. If this cannot be accomplished, the influent to the
lakes should be monitored.
Table 11
Recommended Water Quality Criteria
for Fishing-Boating Lake-*-
Aspect
pH
Total Alkalinity
Dissolved Oxygen
Turbidity
Suspended Solids
Total Phosphorus
Temperature
Fecal Coliform
Criteria
6.0-9.0
> 20 mg/L
> 5 mg/L
< 25 Jackson Units
< 25 mg/L
<0.05 mg/L
< 90°F (Growth) and
< 75°F (Spawning, Egg Development)
< 1,000/100 ml
Source: "Water Quality Criteria", National Technical Advisory Committee
to the Secretary of the Interior, FWPCA, Washington, D.C.,
April 1, 1968.
The experience of the Santee Project is relevant to a discussion of water
quality. The Santee lakes are in an advanced state of eutrophication,
and major fishkills have occurred. The fishkills were attributed to high
temperature and to the depletion of dissolved oxygen resulting from both
the respiration of a predominating growth of algae and the oxygen demand
by the settled algal biomass. The two-year average inorganic nitrogen and
phosphate concentrations in the influent to the lake experiencing the
most severe algae growth were 0.7 mg/L and 1.9 mg/L, respectively. Higher
concentrations of phosphorus were recorded during the periods of the major
fishkills. The BOD of the influent to the lake averaged 3.5 mg/L, and at
this level it did not have a significant effect on dissolved oxygen. In
fact, the effluent from the lake had an average BOD of 6.0 mg/L, nearly
twice as high as the influent concentration. A yield of 400 pounds of
fish per acre per year was obtained from the Santee Lakes during somewhat
balanced conditions.
38
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Indicated Effluent Standards
The previously discussed water quality criteria provide a basis for de-
termining standards for the quality of the influent to the lakes. Ef-
fluent standards based on the water quality criteria and on the waste
assimilative capacity of the lakes are summarized in Table 12.
Table 12
Recommended Standards for Influent to
Recreational Lakes
Aspect
pH, units
BOD, mg/L
Suspended Solids, mg/L
Total Phosphorus, mg/L
Free Chlorine, mg/L
Free Iodine, mg/L
Fecal Coliform/100 ml
Swimming Lake
Min. Avg. Max.
7.5 — 8.0
—
5
10
—
15
50
—
0.05
1
0.5
1.0
5.0
0.5
1.0
5.0
—
—
200
Fishing Lake
Min. Avg. Max.
6.0 — 9.0
5 10
25 50
0.05 1
(See Note)
(See Note)
Note: To promote the growth of aquatic life, the influent to the
Fishing Lake should contain practically no chlorine or iodine,
combined or free; however, to protect public health the influent
should be disinfected.
Water Reclamation Facility Capacity
For a project of this type, the capacity of the water reclamation facility
determines the storage reservoir drawdown rate and the amount of reclaimed
water that can be introduced to a swimming facility. These aspects in
turn affect the frequency of overflow to the Anacostia River and the number
of bathers which can be permitted to use a swimming facility at any given
time.
Swimming Facility Consideration
The number of bathers which may use a swimming facility is limited, in the
interest of health and safety, by six factors:
1. Ratio of non-swimmers to swimmers
2. Bather control
3. Surface area of water available
4. Surface area of the swimming facility
5. Turnover period required to maintain water quality
objectives
6. Capacity of the water reclamation facility
39
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Of these, water reclamation facility capacity is the most critical. The
overall limitation is developed through a series of relationships.
First, the ratio of non-swimmers to swimmers determines area requirements
and average depth, which in turn establish a minimum volume of water for
swimming; turnover period is a function of volume of water and water
reclamation facility capacity; and as a safety precaution, the number of
bathers permitted by these relationships must not overcrowd available
surface area.
Several agencies have established minimum area requirements to provide
bather safety. For swimming pools, The American Public Health Associa-
tion (APHA) standards of 20 sq.ft. for bathers using water shallower than
5 feet, and 36 sq.ft. for swimmers in deeper water, are commonly used (12).
APHA observes that in arriving at these figures, it assumed that only
half the non-swimmers (those using the shallower water) and only two-
thirds of the swimmers are in the pool at any one time. Thus, the APHA
standards for people present at the facility are 10 sq.ft. and 24 sq.ft.
per non-swimmer and swimmers, respectively. For a natural lake, where
there is a strong preference for a lower bather density, the commonly-
accepted standard is 50 sq.ft. per person present at the facility (13).
This latter standard is more appropriate than the APHA standards for
the Kingman Lake Project, because it would provide more space per bather
and avoid the overcrowded conditions prevalent at so many swimming pools.
On the basis of a breakdown of bathers into 75 percent non-swimmers and
25 percent swimmers, the average depth of the swimming area would be
4.5 feet. At this depth, the minimum unit surface area requirement of
50 sq.ft. would mean a minimum of 1,700 gallons of water for each bather
present at the facility but not necessarily in the water. On this basis,
the allowable bather load is a function of water reclamation facility
capacity and of water turnover period. Table 13 is an array of available
area and allowable bathers for various facility capacities and turnover
periods.
This shows that the available surface area is not fixed, but varies
with facility capacity and water turnover period. For the range of con-
ditions presented in the table, it is evident that only part of the
northern section of Kingman Lake can be developed for swimming. The
required swimming area can be hydraulically isolated in the lake without
the use of a physical barrier, by proper design of an automated recircu-
lation system with multiple inlet distribution of purified water at the
shallow edges and pickup for treatment from the deeper water. Automated
monitoring systems and the delivery system controls can be combined to
provide maximum recycle to areas requiring the greatest water turnover.
Effective replacement of water would permit continuous use of all swim-
ming and bathing areas.
Consideration must be given to the quantity of purified water introduced
per bather in the water. Studies performed by various recreational agen-
cies indicate that only about half of the bathers present at a swimming
facility are actually in the water at any one time. Therefore, for water
40
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Table 13
Available Swimming Areas and Maximum
Allowable Number of Bathers for Various
Designs of Water Reclamation Facility
Water Reclamation Facility Capacity
25-mgd
Water Turnover Period
6 Hours
8 Hours
12 Hours
2b Hours
Max imum
Swimming Number of
35-mgd
Acres
4.3
5.7
8.5
17.0
Bathers
3.700
5,000
7,400
14,800
Max Emum
Swimming Number of
50-mgd
Acres
6.0
7.9
11.9
25.8
Bathers
5,200
6,900
10,400
20,800
Max imum
Swimming Number of
Acres
8.5
11.3
17.0
33-9
Bathers
7,400
9,900
14,800
29,600
Note: Maximum available water surface of swimming lake is approximately 46 acres.
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turnover periods of 6 hours, 8 hours, 12 hours, and 24 hours, the puri-
fied water introduced per bather hour is 560 gallons, 420 gallons,
280 gallons, and 140 gallons, respectively. Studies performed by various
recreational agencies suggest the daily turnover rate of users at a bath-
ing beach facility ranges from 1.5 to 3.0, with 3.0 being the predominant
value. For the Kingman Lake Project, in which there will be other activ-
ities besides swimming to interest visitors, the 3.0 turnover rate is
probably appropriate. This suggests that the maximum allowable daily
bather load is three times the values listed in Table 13.
Bathhouse facilities, although not directly related to the size of
swimming facilities, must be considered with regard to their economic
impact on the project. The bathhouse facility sizing has been based
upon a peak bather load of 20,000 at any one time. The assumed
composition of bathers is: 60 percent women and children (using women's
dressing rooms), and 40 percent men.
Six separate bathhouses have been envisioned. The bathhouses will be
separated into men's and women's sections. Each women's section will
provide one water closet per 50 women, one lavatory per 100 women, one
shower per 50 women, and one dressing booth and one basket locker per
20 women. Each men's section will provide one water closet per 75 men,
one urinal per 75 men, one lavatory per 100 men, one shower per 50 men,
and one dressing both and one basket locker per 20 men.
Bathhouse construction is expected to be concrete-slab floors, walls of
stucco on cement blocks, open-top buildings with exposed wooden beams.
Fiberglass or anodized aluminum partitions for dressing room and water
closet stalls, shower rooms (10 showers heads per room), and central
basket locker rooms. Including office and utility space, approximately
13,000 square feet are required for each building.
Drawdo\foi of Storage Reservoir
Besides limiting the number of swimmers which may be admitted to the lake,
the capacity of the water reclamation facility is related to the proba-
bility of overflow exceeding the capacity of the storage reservoir, since
it determines the drawdown rate. Regardless of any selected capacity of
the storage reservoir, it is possible that the combined effect of two or
more storms, occurring within a relatively short period of time, will
result in runoff in excess of the reserve capacity of the reservoir,
even though the separate runoff from each storm is less than the design
capacity.
The investigation of recurring storms is properly in the realm of a
Markov Chain Analysis, but sufficient data are not currently available
to perform this type of statistical analysis. A reasonable determina-
tion of the probability of preventing reservoir overflow can be made by
assuming that rainfall intensity for consecutive 24-hour periods is in-
dependent .
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An overflow of the storage reservoir would have the most serious impact
during the periods when the Potomac and the Anacostla River are at low
flow, i.e. during August, September, and October. This is compounded
by the circumstance that the more intense rainfalls display a higher
probability of occurrence during these months. A Weather Bureau Tech-
nical Paper (14) provides isopleths relating 24-hour duration rainfall,
frequency, and months of the year with various probabilities. The values
in this graph were used to develop a graph of the continuous function
of probability versus frequency for the August-October period. In turn,
this graph was used to determine the probability that the 24-hour rain-
falls of particular frequencies will be equaled or exceeded during that
period.
The typical short summer showers occurring in August, September, and
October have a frequency which cannot be read with accuracy from the
previously described graph; however, the runoff from these storms will
have some effect on the probability of overflowing the storage reser-
voir. To account for this type of runoff, the expected runoff per day
was calculated from the mean rainfall in August-October period, as
reported in a National Weather Center Publication (15). If 60 percent
of the rainfall overflows from the Northeast Boundary Trunk Sewer, a daily
runoff of 9 million gallons can be expected in the August-October period.
Table 14 is a listing of the probability o£ overflow of the storage
reservoir for various water reclamation facility capacities.
Table 14
Probability During August-October
of Two or More Storms
Exceeding Reserve Storage Capacity
Reclamation Probability
Facility of Exceeding
Capacity Storage Capacity
25 mgd 18 percent
35 mgd 9 percent
50 mgd 4 percent
The methodology used was as follows: 1) determine a net drawdown rate
(treatment plant capacity minus 9 mgd); 2) determine for each day the
probability of the 24-hour rainfall resulting in runoff equalling or
exceeding the accumulated net drawdown; and 3) add the dally probabil-
ities.
The capacity to retain combined sewer overflow is Improved with each
increase in treatment plant capacity. The maximum capacity to retain
overflow is equal to the capacity of the storage facilities plus the
accumulated drawdown through the duration of overflow. The volume of
43
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overflow for various rainfall frequencies was based on the 24-hour rain-
fall; therefore, the daily capacity of the water reclamation facility can
be added to the volume of the storage' facility to determine total
capability for retention of overflow.
Treatment Process Investigation and Evaluation
Planning
The FWQA has funded many research and development projects for the
investigation or demonstration of various non-conventional processes
for treating combined sewer overflow. The more promising of these
projects utilized methods involving either screening or filtration
rather than biological treatment methods. In general, the effective-
ness of filtration lies in the fact that combined sewer overflows and
storm water runoff contain large fractions of suspended waste consti-
tuents (recognized to be non-volatile discrete solids) rather than high
concentrations of soluble organics.
The laboratory test program of a previous study (1) on the treatment of
combined sewer overflow indicated that filtration through multi-media
filters is a technically feasible process for the removal of suspended
solids and non-soluble BOD from combined sewer overflows. The applica-
tion of filtration appears promising; however, additional laboratory
study was deemed necessary to:
1. Confirm the results of the previous study.
2. Demonstrate that filtration in combination with other
processes can treat combined sewer overflow to the
quality required for the Kingman Lake Project.
3. Evaluate the performance of filtration and the other
treatment processes under the extended and varying
operational conditions anticipated at the Kingman
Lake Project, i.e. the treatment of recycle water
from the Lake and the treatment of makeup water from
the Anacostia River.
Some of the studies of other treatment processes for combined sewer over-
flow have produced favorable results, and the application of some of
these processes appears to have some promise. In parallel with the la-
boratory work conducted in this study, a literature review of other prom-
ising treatment methods was conducted to evaluate their use in the King-
man Lake Project.
Laboratory Investigation Program and Results
A detailed discussion of the laboratory investigation program and re-
sults is attached in Appendix A. In undertaking the laboratory program,
synthetic wastewater samples were produced which approximated the BOD,
suspended solids, and silt concentrations expected in combined sewer
overflow.
44
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The negligible removal of soluble BOD through a filter system and the
requirement for low effluent BOD concentrations establish a need for an
intermediate organic removal process. Activated carbon adsorption is a
proven process for removing soluble organics in low concentrations, and
laboratory investigations were conducted to confirm its application to
a combined sewer overflow filtration system. The treatability studies
with filtration and carbon adsorption uncovered a potential problem of
fouling of the carbon columns with colloidal solids which would pass
through the filtration process. Consequently, coagulation and sedimen-
tation studies were undertaken to condition or prepare the wastewater
for a more efficient filtration. The laboratory investigation program,
in summary, demonstrated that a treatment system of chemical coagulation,
sedimentation, filtration, and activated carbon adsorption could produce
an effluent having BOD and suspended solids concentrations well below
the maximum levels recommended for the Kingman Lake Project. This per-
formance was demonstrated for conditions simulating: a three-day draw-
down of combined sewer overflow, the treatment of makeup water from the
Anacostia River, and the treatment of recycled water from the swimming
and fishing lakes.
In addition, it was necessary to undertake testing of such aspects as
sludge dewatering, algae growth, and disinfection, to gain more complete
understanding of the effectiveness of the envisioned project. A deten-
tion time of 15 minutes and a chlorine dosage of 2.0 mg/L resulted in a
complete absence of total coliform and fecal coliform organisms in the
final effluent. Preliminary tests of a sludge produced in the demon-
stration unit indicated that a sludge cake satisfactory for disposal
purposes could be obtained through centrifugation.
Although total phosphate removals as high as 90 percent were achieved
in the demonstration unit, algae production from wastewater nutrient
was not inhibited. This can be attributed in large part to the fact
that the phosphate levels in the raw synthetic wastewater samples were
high, approximately ten times as high as those determined in a previous
WESTON study of combined sewer overflow in the District of Columbia.
However, the activated carbon pilot unit studies also showed elutria-
tion of phosphate from the carbon bed when a synthetic wastewater (rel-
atively high phosphorus content) was followed by a reservoir water or
river water run.
It should be noted that a 90 percent removal of the phosphate concen-
tration expected in D.C. combined sewer overflow would produce an efflu-
ent phosphorus concentration of 0.1 mg/L. This is equal to the guide-
line concentration recommended in a study (11) for flowing streams and
twice that recommended for streams entering lakes or reservoirs. Con-
sidering that the swimming lake will have a relatively short water
displacement period and that chlorine, which acts as an algicide, will
be used, it is anticipated that excessive algae growth will not be a
problem in the swimming lake. Since the fishing-boating lake will have
a lower displacement period and an algicide will not be used, excessive
algae growths may present a problem there.
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Literature Evaluation
The laboratory investigation program in this study was limited to the
confirmation of a process involving filtration and activated carbon. A
literature review was conducted of other promising treatment processes
to evaluate their application to the Kingman Lake Water Reclamation
Project. Appendix E gives an account of the literature review of ozona-
tion, rotary vibrating screening, microstraining, and U-tube aeration,
and of their indicated applications. These processes have been demon-
strated to be technically feasible; however, their application to the
Kingman Lake Project may require further development work as well as
confirmation work, and appears to be more costly than the processes
investigated in the laboratory phase of this study. In summary, the
indicated applications of these processes are as follows:
Ozonation - Oxidation of dissolved organic materials in
lieu of activated carbon
- Disinfection of influent to boating-fishing
lake in lieu of chlorination
- Odor control in storage basin
Rotary Vibrating Screening - Removal of suspended solids
in lieu of filtration
Microstraining - Removal of suspended solids in lieu of
filtration
U-Tube Aerators - Alternative aeration device
In addition to reviewing reports related to these alternative projects,
it was necessary to review previous reports (1,16) of the performance of
activated carbon and filtration to determine design parameters. (The
laboratory program was oriented to demonstrate the quality of the efflu-
ent from these unit processes rather than to determine design parameters.)
These reports indicated that the basic design parameters are a flow rate
of 5 gpm/sq.ft. for multi-media filtration, and a flow rate of 6 gpm/sq.ft.
and a detention time of 29 minutes for activated carbon adsorption.
Presentation of Alternatives
The foregoing criteria establish that there are numerous alternative
strategies for collecting, storing, and treating overflow. The process
of selecting the appropriate alternative, i.e. the alternative which
represents a balanced assessment of the costs and benefits involved in
the project, is facilitated by reducing the unwieldy number of feasible
alternatives to those offering a reasonable, but wide choice. Following
is a presentation of these alternatives. A discussion of the costs and
distinct benefits associated with each is discussed in a subsequent sec-
tion.
46
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Storage Alternatives
Within the confines of the Anacostia River, East Capitol Street Bridge,
and the proposed East Leg Freeway, it is possible to construct a surface
storage basin having from 90 to 235 million gallons of storage capacity;
these limits as well as an intermediate capacity of 175 million gallons
present a reasonable range of choices.
Another option is tunnel storage. Besides the capability to store over-
flow, the tunnel storage concept provides sewer relief and reduces the
frequency of surcharging. More soils evaluation is needed to satisfac-
torily engineer this concept; however, the evaluation of an 85-million
gallon tunnel permits a reasonable comparison of surface and tunnel
storage.
Water Reclamation Process Alternatives
The laboratory investigation program in this study demonstrated an ef-
fective system of processes for treating overflow. A literature evalua-
tion disclosed that there are some promising alternatives to those unit
processes investigated, e.g. fiberglass filtration, microstraining,
ozonation, and U-tube aeration. Whereas, the process developed has been
demonstrated to be technically sound, some development or confirmatory
work on each of the alternative unit processes would be required. In
this light, only the process design confirmed in the laboratory study
will be presented.
Nevertheless, the opportunity presented at the proposed Kingman Lake fa-
cility for operation of a field test unit of significant magnitude should
not be overlooked. An adequate amount of space (yet only a small fraction
of the total available space of the reclamation facility) could be used
for pilot-scale facilities for the investigation and development of prom-
ising alternative unit processes for the treatment and reclamation of
combined sewer overflows. The justification for such an investigative
and demonstration facility is the clearly demonstrated fact that pollu-
tion from combined sewer overflows is a substantial portion of the over-
all stream pollution problem.
Reclamation Facility Capacity
Based on the allowable bather load associated with various plant capa-
cities, the drawdown rate of the storage basin and its relationship to
overflow of the basin from repeat storms, and the additional storage
provided by the plant operating during the period of the storm, the
following reclamation facility capacities were considered reasonable
for economic and environmental evaluation: 25 mgd; 35 mgd; 50 mgd.
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SECTION VI
CONCEPTUAL ENGINEERING DESIGN
General Design Basis
The conceptual design of the facilities required in this project is based
on varied information provided by a number of separate studies. These
studies range from investigations providing definitive information, such
as the detailed soils analysis in the field and the process investiga-
tions in the laboratory, to less conclusive studies requiring assumptions,
such as the hydrological study. When assumptions have had to be made,
the basis for those assumptions has been described.
In general, the factors which constitute the basis for design are:
1. Expected wastewater characteristics (as defined in a pre-
vious study (1) of combined sewer overflow in Washington,
D.C.) and the wastewater quantities determined for over-
flows from the Northeast Boundary Trunk Sewer.
2. Wastewater treatability parameters derived from labora-
tory evaluation and published reports.
3. Effluent quality requirements.
The factors which have significant influence both on the conceptual de-
sign and on the economic evaluations are:
1. Selection of a specific storage capacity (which consti-
tutes an implicit measurement of the pollution abatement)
and of a water reclamation facility capacity will be
deferred until after the economic evaluations in a later
section of this report. However, to facilitate descrip-
tion of the conceptual design and to provide a workable
basis for making cost estimates, a 50-mgd water reclama-
tion facility and a 175-million gallon storage basin are
illustrated in detail. Flow diagrams, hydraulic profiles,
and related items for these capacities will be essentially
the same for facilities with other capacities.
2. Requirements for the quality of influent to the fishing-
boating lake and the swimming lake reflect established
criteria.
3. A treatment system of chemical coagulation, sedimentation,
filtration, and activated carbon adsorption has been
demonstrated in a laboratory investigation program to
produce an effluent having BOD and suspended solids con-
centrations within the allowable limits recommended for
both the fishing and the swimming lakes.
49
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4. The use of certain treatment processes as replacements for
those studied in the laboratory investigation program has
been established in other studies to be technically feasi-
ble. The conceptual design proposed in this report uti-
lizes only those processes, with minor exceptions, confirmed
in the laboratory studies; however, other waste treatment
processes, e.g. ozonation, microstraining, U-tube aeration,
etc. can be incorporated in the overall design to satisfy
any interest by the FWQA to demonstrate them.
5. The laboratory program was oriented to demonstrate the
quality of effluent which can be produced in conditions
simulating those anticipated at Kingman Lake. Actual
design parameters (e.g. activated carbon) were taken
primarily from previous FWQA studies.
Soils Investigation
Subsurface Data Collection
Prior to the field investigation, test boring and laboratory test data
were obtained from D.C. Highway Department pertaining to the existing
East Capitol Street Bridge and to the proposed East Leg Freeway along
Kingman Lake. Additional subsurface studies made by the Washington
Metropolitan Area Transit Authority for the proposed subway system were
reviewed. Review of the existing data aided in planning the field
investigation and in the final analysis of the results.
Test Boring Program
The preliminary test boring program was started on February 2, 1970.
Twenty-two borings were drilled for this investigation by Warren George,
with inspection provided by Joseph S. Ward and Associates. The borings
ranged in depth from 30 to 105 feet, and included six 4-inch borings made
to obtain undisturbed samples for strength and compressibility testing
in the laboratory, and seven borings drilled in the lakes. With the
exception of the 3-inch undisturbed samples, the other samples were
obtained by the Standard Penetration Test Method. Individual sample
descriptions on the boring logs and laboratory identifications are in
accordance with the Burmister (ASEE) Classification System, while the
generalized strata descriptions are based on the Unified Soil Classi-
fication System. The detailed logs of the individual borings are shown
in the Soils Engineering Report (Appendix C).
Piezometer Measurements
Piezometers were installed in four selected borings set in the sand and
gravel stratum which overlies the stiff clay. The recorded ground-water
levels vary between +2 and +5, which is slightly above tide level. This
would suggest that there might be a slight artesian pressure in this
stratum. Ground-water level measurements taken in other test borings
50
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are presumed to represent water table conditions in the fill. These
range from elevation -8 to +3 and indicate that water levels are near
river level and generally change with tidal fluctuations.
Laboratory Testing
All samples taken in the field were delivered to Joseph S. Ward's soil
testing laboratory. All samples were inspected, and tests were performed
on selected samples. The tests performed in the laboratory according to
the accepted procedures (Atterberg Limit determination, mechanical anal-
ysis, natural moisture content determination) were performed on both un-
disturbed samples and samples obtained by the standard penetration test.
Unconfined compression, consolidation, triaxial compression, and labora-
tory vane shear tests were performed only on the undisturbed samples.
The tabulated results of the laboratory testing program are given in
Appendix C, along with a brief description of the methods used in perform-
ing the more complex tests.
Data Analysis
All soils and foundation data obtained during the course of the project,
which includes results of prior investigations, the current .fiild in-
vestigation, and the laboratory testing program, have been correlated
and interpreted by the soils consultant, Joseph S. Ward and Associates.
They have made an evaluation of the data, and have arrived at preliminary
conclusions pertaining to the proposed structures. Their evaluations,
conclusions, and recommendations are presented in Appendix C. The
following significant findings, conclusions and recommendations have
been excerpted from the soil report.
Soil Considerations
The soil conditions in the vicinity of Kingman Lake require special con-
sideration in the construction of a storage basin and in the development
of lakes suitable for fishing, boating, and swimming.
Storage Basin
The soil stratum which would have the greatest effect on the construction
of a storage basin is the organic clay and peat, which was found in all
borings. The extremely soft and compressible nature of this stratum
prohibits the founding of structures on or above it, because of the danger
of settlement. Due to the weakness of the material, excavations must be
braced to resist high lateral loads, and in open cuts relatively flat
side slopes are required to insure stability. For this reason, and be-
cause of ground-water conditions and the proximity of the river, it was
recommended by the soil consultant that the concrete slurry wall method
of construction be used.
The overlying fill has compressed and somewhat strengthened the organic
material. However, this improvement is not deemed' significant with respect
51
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to rigid structures. Actually, the presence of the fill aggravates cut
slope stability problems and increases lateral soil pressure on temporary
and permanent walls.
The sand and gravel and the stiff clay underlying the organic material
can provide good foundation support, and are, therefore, a logical limit
for the excavations under consideration. Field investigation indicates
that the sand and gravel zone is quite permeable, increasing its signi-
ficance with respect to lateral and uplift pressures on deep structures.
To provide maximum storage volume, construction of a storage basin with
vertical walls is recommended. The bottom of this basin would be approx-
imately at elevation -40. Due to the ground-water level and presence of
weak organic soil, high lateral pressures are expected to act upon the
walls. Diagrams showing the typical lateral pressures on both temporary
and permanent walls are shown in Appendix C.
In order to serve effectively as cut-off walls to prevent seepage of
ground water into the structure during and after construction, the
bottom of the storage basin walls should extend well into the underlying
stiff clay. To insure stability of the walls during all stages of
excavation and bracing, a minimum wall penetration below the bottom of
the tank of 15 feet would be required. In the case of the proposed
structure, this would extend the walls to elevation -55. As mentioned
in the Soils Report, a tie-back system for restraining the slurry wall
is not practical because of poor soil conditions, and to obtain the
required bracing it will be necessary to design an internal bracing sys-
tem. With the inclusion of a vehicle parking roof as an integral part
of the storage basin, the need for internal bracing would be reduced.
As envisioned, the parking roof would be designed for passenger car
loading. However, if required, sections of the roof can be used as
truck routes for servicing the water reclamation facility and must be
designed accordingly. The structural design will make the maximum use
of precast, prestressed beam and girders, which will facilitate con-
struction and reduce construction costs.
Spread footings for support of the storage basin roof may be founded in
the stiff clay or overlying sand and gravel zone. The net design bear-
ing pressure has been determined to be 3.0 tons per square foot (tsf).
The base of the footings should be a minimum of A feet below the bottom
of the storage basin to justify this design pressure.
Caissons or piles are also suitable for roof support. Where these units,
deep walls, or footings extend below elevation -50, a design bearing
pressure of 4.0 tsf may be used. For purposes of estimation, a 50-ton
steel pile may be assumed to reach capacity when driven to a pile tip
elevation of -90.
Slurry wall construction will be used in the construction of the water
reclamation facility building. It is anticipated that the slurry wall
would be constructed around the perimeter of the building so that it
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would function both as a foundation wall and as a hydraulic cut-off wall.
Where the slurry wall extends into the existing lake, earth fill must be
placed to provide a construction platform. These dikes should have a
minimum top width of 24 feet built up to elevation +6, and would require
low side berm approximately 25 feet wide on either side of the main dike
to insure its stability. Dike construction should be kept at least 80
feet (horizontal distance) from the East Capitol Street Bridge to prevent
any detrimental effects on the bridge foundation.
Settlement of spread footings is estimated to be 1 to 2 inches, with
respect to the surrounding area, for footings designed with a bearing
pressure of 3.0 tsf. Settlement of caisson or pile foundations will
be negligible if properly installed, and should not exceed the elastic
deformation of the piles of caissons.
Due to the excavation, there will be a stress release in the stiff clay
underlying the storage basin. Theoretical analysis, based on an exca-
vation period of one year, indicates the post excavation heave to be
3 and 2 inches at the center and perimeter of the basin respectively.
Relative movement between the soil^at the floor of the basin and at
the wall and roof foundations will occur. The walls and structural
foundations will settle slightly, while the clay in between will heave.
The effects of stress release will extend to the area immediately out-
side the storage basin. If the distance between the north wall of the
storage basin and the East Capitol Street Bridge is 100 feet, the heave
could be as much as 0.3 inches over a 30-year period. This amount,
which should also be anticipated at the location of other adjacent
structures, is insignificant.
Since a concrete bottom slab is desirable to facilitate cleaning of the
storage basin, it is recommended that it be constructed in relatively
small sections that can undergo moderate differential settlement without
cracking. In addition, the bottom slab should be constructed on a gra-
vel base and designed with open joints at walls and footings. These
open joints should allow any excess hydrostatic pressure to dissipate
and would probably be more reliable than relief valves.
Fishing and Bathing Lakes
In their present shallow condition, both the proposed fishing and bathing
lakes will require excavation of bottom material. It has been estimated
that the fishing lake will require 4 feet of excavation, while the bath-
ing lake will require an average of 7 feet. These depths of excavation
are deemed necessary to provide adequate depths for boating, fish propa-
gation, and swimming, and to remove undesirable soil materials from the
lake bottoms. On the bottoms of both lakes, there is a layer of organic
silt approximately 1 foot thick, which exists in a semi-liquid condition.
This layer should be removed; otherwise it could be stirred up easily
and could contaminate the water. In addition, this material will be
disturbed by the placement of a granular blanket and would redeposit
over it.
53
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In the case of the bathing lake, excavation will uncover the organic silt
and clay which would not be suitable for bottom material, thus making it
necessary to backfill with a sand blanket. It is recommended that this
sand layer be not less than 3 feet thick in areas where the water is less
than 7 feet in depth. In deeper areas, the thickness can be reduced to
1-1/2 feet. In order to prevent fine material from the miscellaneous
landfill from being washed into the lake, it is recommended that the ex-
isting fill along the proposed beaches be covered with a minimum of 1-1/2
feet of clean sand and gravel.
For the boating and fishing lake, it is also advisable to cover the lake
bottom with a 1-1/2- to 2-foot blanket of clean sand and gravel. The
sand bottom is desirable from an aesthetic standpoint and for the purpose
of providing a bottom conducive to the growth and propagation of desired
aquatic life.
In regard to the excavation of both lakes, the most suitable method has
been determined to be hydraulic dredging. Because of the several low-
level bridges across the Anacostia River, large barges and bucket dredges
are unable to get upstream as far as Kingman Lake. Therefore, the exca-
vation materials will have to be pumped to a location downstream of the
low bridges for removal by barge or pumped all the way to the disposal
site.
Currently it is proposed that the waste dredging from the project con-
struction be disposed of at the Dyke Marsh area, a part of Section 5 of
the George Washington Memorial Parkway, U. S. Reservation 404V, South
of Alexandria, Virginia. This site, however, will not be available if
any considerable delay is encountered in starting the project. A permit
from the National Park Service, U. S. Department of Interior, will be
required for use of the Dyke Marsh area for disposal.
The sand and gravel material excavated from the area of the storage basin
can be utilized as the granular bedding for the fishing-boating lake and
for the bottom portion of the proposed beach and bathing lake. The top
granular layer in the bathing lake and beach areas should be clean,
washed, commercial white sand.
Maintenance of a water level in the bathing and fishing lakes at an ele-
vation of approximately 3.5-4.5 feet (about 1 foot above normal high river
level) would permit the lake to overflow into the river by gravity under
normal conditions, and to prevent flow of contaminated river water back
to the lakes either through the ground or through the lake outlet system.
By raising the water level in the lakes, ground-water levels in the vi-
cinity of the site can be expected to rise to this proposed level. With
the higher ground-water level, some seepage of water to the river should
be anticipated.
A major factor that will have a marked effect on ground-water conditions
is the proposed flood protection dike. To prevent inflow of river water
to the lakes during flood periods, the dike must be impermeable. Such an
54
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impervious dike will not only prevent flood waters from entering the
recreation area, but will minimize or prevent loss of water from the
lakes to the river.
The flood protection dike is to be constructed by the D.C. Department
of Highways to provide protection for sections of the proposed East Leg
Freeway against the 100-year flood (hurricane) conditions. During high
water or flood conditions in the Anacostia River, gravity overflow from
the lakes into the river will be stopped by the tide gates, and dis-
charge into the river will be accomplished by pumping.
Description of Proposed Facilities
Discussion of Process
Architect's drawings of the general layout, and preliminary plot plan,
schematic flow diagram, and hydraulic profile (Drawings 2, 3, 4, 5,
10, 11, and 12) are presented here. A Summary of Design Basis and
Major Unit Sizes and detailed flow diagrams (Drawings 101 through 107)
are presented at the end of this section.
Combined sewer overflow from the Northeast Boundary Trunk Sewer is
presently discharged to the Anacostia River through an existing triple-
span sewer. This sewer will be intercepted downstream of the three cast
iron tide gates, and the overflow will be directed north along the river
approximately 2,000 feet to the proposed water reclamation facility. A
portion of this extension will be constructed below the proposed East
Leg Freeway.
In addition to the combined sewer overflow, the storm water discharges
from the immediate Kingman Lake Drainage Area (D.C. Stadium, National
Arboretum, etc.,) will be collected; this is presently conveyed through
ten storm sewer lines discharging at various points along the west
shoreline of Kingman Lake. The existing storm sewer lines will be in-
tercepted and piped to the influent of the proposed storage basin.
The combined sewer overflow from the Northeast Boundary Trunk Sewer
and the local storm drainage will enter a diversion chamber, where the
initial portion of the storm flow (up to 175,000,000 gallons) will be
directed to the storage basin. Liquid level in the storage basin will
be used to control the closing of a sluice gate to the basin and at the
same time to activate the bypass to the Anacostia River. Emergency
pneumatic controls will also be provided in the event of a power failure.
The flow will pass through heavy-duty steel trash racks provided for
removal of debris. The trash rack in each chamber will be approximately
fifty feet wide and operated at a maximum of thirty feet Side Water
Depth (SWD). Debris collected on the racks will be removed with a
traversing, manually-operated trash rake and be conveyed to a storage
hopper before being trucked to disposal. An overhead crane will be
provided to remove heavy objects and also to serve as a back-up trash
rake.
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IN ADDITION TO THOSE FACULTIES RECOMMENDED IN THIS REPORT. THIS DRAWING SHOWS THE
COMPLETE DEVELOPMENT OF KINGMAN LAKE RECREATION AREA ACCORDING TO HALPRIN PLAN
DWG. 2
KINGMAN LAKE DEVELOPMENT
WATER RECLAMATION AMD RECREATION FACILITIES
BARTLEY LONG MIRENOA REYNOLDS « NOBLE ARCHITECTS
-------
ELEVATION FROM RIVER
fW 50-0*
ELEVATION FROM LAKE
1-50 - 0*
KINGMAN LAKE DEVELOPMENT
WATER RECLAMATION FACILITY
BARTLEY LONG MIRENDA REYNOLDS & NOBLE ARCHITECTS
1-50-0"
PLAN EL. 15.0
f» 50 -0"
ROOF PLAN
r= 50-0"
DWG. 3
-------
KINSMAN LAKE
MMTCR RTI * MAT ION /*
¦ARTLEV LONG MKNW
DEVELOPMENT
- -M*0 ITQAAM *ACM.IT«
WVNOLD6 4 NOBLE ARCHITECTS
¦XIS
ITINO
CAKK
ANACOSTIA KIVCK
DWG. 4
OSMMVATIPM PAVILION
-------
Alte
inCHI"019
„»FtuEV 1-OMO
-------
FEDERAL WATER QUALITY ADMINISTRATION
KINGMAN LAKE PROJECT
WATER RECLAMATION FACILITY
PLOT PLAN
DWG. 10
-------
FEDERAL WATER QUALITY ADMINISTRATION
KINGMAN LAKE DEVELOPMENT
WATER RECLAMATION FACILITY
SCHEMATIC FLOW DIAGRAM
-------
FEDERAL WATER QUALITY ADMINISTRATION
KINGMAN LAKE DEVELOPMENT
WATER RECLAMATION FACILITY
HYDRAULIC PROFILE
40 40
INTERCEPTOR DIVERSION
EXTENSION CHAMBER BAR RACKS GRIT CHAMBER STORAGE BASIN INTAKE AND SURGE TANK
ACTIVATED CARBON
COLUMNS
NOTE: ALL ELEVATIONS REFER TO THE D. C. DATUM,
WHICH IS 3.7 HIT ABOVE THE USC&GS
MEAN SEA LEVEL DATUM.
DWG. 12
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The wastewater passing through the trash racks will enter the grit cham-
ber section of the storage basin. The grit chamber will be designed to
allow grit and heavy material to settle out in a relatively confined area,
in order to prevent solids deposition in the main part of the storage
basin. This chamber will be designed to have a detention time of less
than three minutes at the peak flow rate of 4,500 cfs. The chamber will
have approximate dimensions of 150' by 500', with a partition wall pro-
viding approximately ten feet SWD before the wastewater from the combined
sewers overflows into the main storage area. The grit and heavy organics
remaining in this basin after the wastewaters have been removed will be
flushed with high pressure hoses to a common area for removal. Lift pumps
will be provided in this basin to pump the heavy grit and organic material
to centrifugal cyclone degritting facilities to separate the grit from
the organic material. The grit will be hauled away, and the organic ma-
terial in solution will be discharged to the surge tank at the influent
to the wastewater reclamation plant.
Wastewater overflowing the grit chamber will enter the main storage
basin. This basin will provide a maximum capacity of 175,000,000 gal-
lons at a maximum liquid depth of thirty-five feet. A combination of
bridge-mounted mixers and floating aerators will be provided in this
basin to maintain an aerobic system as well as to provide mixing. The
total storage basin, Including the grit chamber section, will be covered;
most of the area above the basin will be designed to allow for parking,
while a portion of the area will be under the elevated highway. Air
enclosed in the storage basin above the water level will be displaced
by natural ventilation with at least one displacement per hour. The
need for odor-control facilities has not been established and should
be evaluated as part of the detailed engineering design. However, monies
for ozone facilities have been included in the current estimates in the
event further investigation indicates that they are needed.
Wastewater from the storage basin will enter an intake surge tank. Back-
wash waters from the mixed-media filters and the activated carbon columns,
as well as centrate from the centrifuges and spent carbon slurry water
underflow from the dewatering screens, will be discharged into this
tank.
Wastewater pumped from the intake surge tank will be divided equally
between two parallel sets of flash-mix tanks, flocculation tanks, and
sedimentation tanks. The flash-mix tanks will be designed to provide
a detention time of approximately 1.7 minutes at the design flow of
50,000,000 gallons per day. Coagulant, coagulant aid, and caustic
storage will be provided, and the chemicals will be added ahead of
the flash-mix tanks as required. The coagulant could be any one of
a number of inorganic chemicals, and the coagulant aid would be an
organic polymer. After passing through the flash-mix tanks, wastewater
will proceed to the flocculation tanks, where a detention time of ap-
proximately 16.8 minutes will be provided at the design flow rate.
Flocculation in these tanks will be accomplished by three rows of hori-
zontal mixers. After flocculation, the wastewater will proceed to the
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sedimentation tanks, (detention time approximately 108 minutes; design
overflow rate approximately 1,480 gallons/day/sq.ft.)• The two sedi-
mentation tanks will have fifteen feet SWD, which will allow for some
sludge storage capacity.
Sludge dewatering and disposal from the two sedimentation tanks will be
accomplished by on-site sludge dewatering facilities consisting of ten
basket centrifuges followed by storage units for the (approximately) six
percent sludge. Approximately 130-150 Tons/day of sludge (dry solids
basis) would require disposal. There are two sludge disposal alterna-
tives available: pump the six percent sludge directly to a barge; or
return to the basket centrifuges for further dewatering to fifteen per-
cent and convey to trucks for disposal. Pilot-scale centrifugation
studies should be conducted in the next phase of engineering to confirm
the process design assumptions made in Phase I.
Ultimate sludge disposal during the first two years of operation can be
accomplished at the Dyke Marsh area. This disposal area, however, will
not be able to accommodate spoil material for any significant length of
time. A survey of potential future spoil areas must be initiated at the
same time engineering design of the project begins. This will allow ap-
proximately four years to develop additional sites for sludge disposal.
Any concerted effort to develop future sludge disposal sites in the
vicinity of Washington, D.C. should include considerations for sludge
disposal from the District of Columbia's Blue Plains Water Pollution Con-
trol Facility.
Clarified supernatant from the sedimentation basin will overflow into a
channel that will convey the wastewater by gravity to ten multi-media
filters. These filters will be designed with media of different specific
gravities (anthracite, sand, garnet, and gravel) for an average gravity
flow rate of 5 gpm/sq.ft. A maximum hydraulic capacity of 10 gpm/sq.ft.
will be provided. The filter backwash system is designed to clean such
filter once per day at a rate of 20 gpm/sq.ft. for a period not to exceed
10 min/day. Surface wash will be provided on each filter. Backwash
water for the filters will be stored in an elevated storage tank with
a capacity of 250,000 gallons. Filtered water will discharge to the
clearwell located directly below the filters.
Filtered water from the clearwell will be pumped to activated carbon
columns for the removal of soluble organics. Fourteen single-stage
units, plus two stand-by units, will provide a surface loading of 6
gpm/sq.ft. and a contact time of approximately twenty-nine minutes at
the design flow of 50,000,000 gal/day. These activated carbon columns
will contain 8 x 30 mesh granular activated carbon.
Effluent from the activated carbon column will discharge to the chlorine
contact tank, located adjacent to the clearwell, where the treated water
will have a detention time of approximately twenty minutes at the design
flow rate. Bacteria and virus control will be maintained with chlorine
and iodine. Three chlorinators, each with a capacity of 4,000 lbs/day,
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as well as one evaporator will be provided. Chlorine will be stored in
one-ton containers, and an area will be provided for storage and handling
of twelve containers on the floor and four on the scales. The chlorine
feed facilities will be designed to provide sufficient chlorine for
break-point chlorination. Iodine feed facilities will be provided for
the addition of potassium iodide in order to maintain residual iodine
in the effluent.
Effluent from the chlorine contact tank will be pumped to two different
facilities. The major flow (approximately 45-50 mgd) will be pumped to
the bathing lake and will be distributed so as to obtain the greatest
dispersion to the swimming areas of the lake. A minimum amount of for-
ward flow (0 to 5 mgd) will be pumped from the chlorine contact tank
to a dechlorination column. This dechlorination column will contain
14 x 40 mesh granular activated carbon, which will be hydraulically
loaded at a rate of 2 gpm/sq.ft. After removing the chlorine residual,
the effluent will discharge to the fishing and boating lake.
Effluent from both the fishing and bathing lakes can be discharged either
to the Anacostia River or be recycled to the wastewater reclamation
facility. Recycle to the wastewater reclamation facility can be directed
either to the head end of the storage basin, to the flash-mix tanks, or
directly to the multi-media filters. Normally, this recycle flow will
go directly to the multi-media filters and then to the remainder of the
treatment facility.
A sightwell will be provided as a part of the clearwell, to allow visi-
tors to the plant to observe the water going to the swimming and fishing
lakes.
Carbon regeneration facilities will be provided to regenerate carbon
on-site. When the instrumental controls of the individual carbon units
indicate that the bed of activated carbon has been spent, the plant
operator will take that carbon column off stream and regenerate it.
The spent carbon will be discharged to a spent carbon slurry tank, where
a carbon slurry will be held and then pumped to the top of a stationary
dewatering screen. Carbon will gravity dewater to approximately four
percent solids and then discharge into the regeneration furnace. The
underflow liquid from the dewatering screens (as well as the water from
the wet scrubber) will be pumped back to the intake surge tank. A six-
hearth regeneration furnace, capable of handling 160,000 lbs/day of
spent activated carbon, will be provided. This furnace will include
wet scrubbers for air pollution control, drive mechanism, duct work,
induced draft and combustion air fans, and burner and cooling fans.
Regenerated carbon from the furnace will discharge to a carbon quench
tank and then be pumped to an empty carbon column, with the quench
water coming from the clearwell.
A fresh carbon storage tank, sized for approximately one month's capa-
city based on daily operation and make-up of spent activated carbon,
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will be provided. A screw feeder will discharge fresh carbon from the
storage tank at a controlled rate to a slurry pump, where the carbon
will be transported to an empty carbon column.
Make-up water to balance evaporative losses (estimated to be 200,000
gallons per day) during periods of dry weather will be pumped from the
Anacostia River to the covered storage basin.
Seasonal Operation
The operation of the treatment and recreational facilities will vary
during the year. While the occurrence of rainfall is more likely in
certain times of the year, it can occur at practically any time. On the
other hand, the recreational aspects of the facility, namely swimming,
boating, and fishing, will be active only at certain times of the year.
Consequently, since the operation of the water reclamation facility is
expected to vary, discussion of the operation has been divided into dry
and wet weather and into swimming and non-swimming phases.
During and shortly after a heavy rainfall, overflow from the combined
sewer will enter the storage facility, where it will be held for treat-
ment. Based upon the maximum capacities of the storage lake and of
the water reclamation facility, this overflow can be treated in less
than four days. During these peak treatment rates, the normal operating
staff will have to be supplemented by an auxiliary operating staff.
After the wastewater in the storage lake has been drawn down to a low
level, the reclamation plant throughput rate can be significantly reduced,
operated at a low rate using make-up water from the Anacostia River, or
even can be shut down. The normal operating staff should be capable of
handling this operation. Grit and settled material will be removed as
necessary when the storage tank is empty, which is feasible during an
extended dry-weather period (Normally, a level of about one foot of water
would be maintained in the storage between storms, to prevent the emis-
sion of undesirable odors). The auxiliary operating staff can perform
this function.
Operation of the facilities will vary between swimming and non-swimming
seasons. This assumes that the boating-fishing facility will be operated
only during the swimming season. If boating and fishing activities have
different season than swimming, the overall schedule will have to be
modified. The swimming season is generally established to run between
Memorial Day and Labor Day. During this period, the reclamation plant
will have to handle 50 mgd continuously. If there is wastewater overflow,
this will be treated and discharged to the swimming lake, with a small
portion of the flow dechlorinated and discharged to the boating lake. If
there is no wastewater overflow to treat, then recycle from the swimming
lake supplemented by a small recycle flow from the boating lake will be
taken back to the reclamation plant. Anacostia River water will be used
to make up evaporative losses. Operation during the dry-weather swimming
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season should be able to be handled by the normal operating staff. The
auxiliary operating staff will again be required after periods of combined
sewer overflow. During the non-swimming season, treated effluent may
be discharged to the Anacostia River rather than to the swimming or boat-
ing lakes, if determined by the operator to be feasible.
Manpower Requirements
The general philosophy in staffing the facility proposes that a perma-
nent full-time crew be provided to operate and maintain the facility
on a year-round basis. This staff will also be adequate to run those
portions of the plant which are required on a continuous basis during
summer months and will provide most of the manpower for peak operation
periods. An auxiliary operating staff will supplement the permanent
staff after periods of heavy rainfall when the total plant facilities
are in full operation. The auxiliary staff would generally be required
for only three or four days at a time.
The permanent operating staff will include personnel necessary for round
the clock maintenance on all the facilities and for operation of those
facilities that are continously operated. The facilities that will be
continuously operated (at least during the swimming season) include the
filters, carbon columns, and chlorination system. The recommended staff
is as follows:
1. One superintendent with education, training, and exper-
ience to be qualified for an engineering management
position.
2. Two laboratory staff people, one of whom must be a
competent chemist; the second should be a qualified
chemical technician.
3. Four shift operators capable of assuming responsibility
for control of unit operations and directing the work
of assistant operators and laborers; these individuals
should have experience in the field of water and/or
wastewater treatment.
4. One maintenance foreman and two maintenance specialists
capable of performing routine repair work in the
mechanical and electrical (including instrumentation)
fields; they should be experienced people but not ne-
cessarily in the field of water or wastewater treatment.
5. Four assistant operators capable of executing routine
operational procedures (i.e. equipment startup, filter
backwash, preparing chemicals, etc.) under the guidance
of the shift operator; these people should be considered
as potential future shift operators.
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6. Four laborers, to provide assistance to the operators
and maintenance people as needed, and to handle gen-
eral housekeeping chores within the plant; considera-
tion should be given to possible training of these
people for future operator responsibility.
During periods of storm flow (during and immediately after storms), and
while the storage basin is being drained, additional personnel will be
required for operation of the clarifiers, centrifuges, bar-rack facili-
ties, and chemical make-up and feed facilities. While the grit collec-
tion basins will be used during storm periods, cleaning will not be ne-
cessary. The permanent staff can clean the basin when time is available,
or the auxiliary staff can be used an additional day or two for this
cleaning. Personnel from the Blue Plains Staff on an overtime or tempo-
ary assignment basis appears to be most feasible source of the supple-
mental manpower. This additional manpower is recommended as follows:
Six assistant operators capable of assuming tasks with
coagulation and sedimentation, centrifugation, and bar
rack cleaning and operation.
During the peak periods, two such people will be required per shift, 3
shifts per day, for periods up to 4 days. Full-time coverage of the
centrifuge operation is anticipated, with general assistance provided
in the other areas.
68
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SUMMARY OF MAJOR EQUIPMENT SIZES
Screening Building
Bar Rack
Des ign Flow Rate
Veloc i ty
Bar Spacing
Number of Chambers
Chamber Dimensions
Width
Depth
Trash Removal
Storage Lake
Grit Chamber
Design Flow Rate
Detention Time, minutes
Main Dimensions
Length
Width (average)
Depth
Capac i ty
Grit Col lection
Degritting Faci1ity
Type
Capac i ty
Storage Basin
Number of Basins
Capacity, approximately
Surface Area, approximately
Depth
Maximum
Minimum
M i xe rs
Type
Number of Mixers
Capacity, each
4,500 cfs
1.5 fps
2 inches
One
100'
30' SWD
Overhead crane and traversing
trash rake
4,500 cfs
5
500'
150'
10' SWD
750,000 cu.ft.
Flush to slurry pumps, pump
to degritting facilities,
truck to disposal
Cyclone
2 at 1,000 gpm each
One
175 x 10a gallons, maximum
675,000 sq.ft.
35'
3*
Bridge mounted
12
100 HP
69
-------
Aerators
Type
Number of Aerators
Capacity, each
Surge Tank
Capacity
Maximum Depth
Lift Pumps
Number
Capacity
Flocculat ion-Clarif icat ion Fac?1it ies
Flash Mix Tanks
Number of Units
Capacity, each
Main Dimensions
Length
Width
Depth
Freeboard
Detention Time
Mixer, each tank
Materials of Construction
Flocculation Tanks
Float ing
8
100 HP
600,000 gal Ions
1*0' SWD
Three
17,500 gpm each
Two
30,000 gal Ions
20'
20'
10' SWD
2'
1.7 minutes
1 at 1 HP
Concrete
Number of Units
Capacity of each
Main Dimensions
Length
Width
Depth
Freeboard
Detention Time, each
Mixers, each tank
Materials of Construction
Sedimentation Basins
Number of Units
Capacity, each
Main Dimensions, each
Length
Width
Depth
Freeboard
Two
292,500 gallons
1+01
65'
15' SWD
2'
16.8 minutes
3 rows at 7.5 HP
Concrete
Two
1.9 mill ion gal Ions
260'
65'
15' SWD
2'
70
-------
Detention Time, total
Design Overflow Rate
Design Weir Loading
Materials of Construction
Sludge Removal
Sludge Pumps
Number of Pumps, each unit
Capacity., each
Type
Coagulant Facilities
Bulk Storage Tank
Number of Units
Main Dimensions
D iameter
Height
Capac i ty
Materials of Construction
Pumps
Number
Capaci ty
Control
Coagulant Aid Facilities
Makeup Tank
Number of Units
Capacity, each
Materials of Construction
Tank Agitator
Number of Units
Horsepower
Dilution and Feed Tank
Number of Units
Main Dimensions
Diameter
Height
Capacity
Materials of Construction
Tank Agitator
Number of Units
Horsepower
108 minutes
1,1*-80 gpd/sq.ft.
20,000 gpd/lin. ft.
Concrete
Positive Displacement
Two
1,000 gpm
Positive Displacement
Three
12'
15'
12,000 gallons
Coated Steel
Two
250 gpm, each
Variable speed and variable
stroke
Two
1,200 gal Ions
Coated steel
One
One
One
12'
15'
12,000 gallons
Coated steel
One
Two
71
-------
Polymer Pumps
Number of Units
Capacity, each
Type
Caustic Storage Tank
Number of Units
Capacity, each
Pumps
Type
Control
Sludge Disposal Facilities
Sludge Volume
Max imum
Minimum
Dry Sol ids
Maximum
Mi n imum
Centr i fugat ion
Number of Units
S i ze
Type
Centrate
Siudge
Multi-Media Filters
Type
Number of Units
F i1trat ion Rate
Flow Control
Area Required, each
Main Dimensions, each
Length
Wi dth
Depth, total
Freeboard
Maximum Filter Head
Maximum Backwash Rate
Backwash Cycle
Backwash Control
Number of Surface Washers/Filter
Type
Capacity, each
Two
100-1,000 gph
Diaphragm metering with vari-
able speed and stroke
Three
12,000 gallons
Two
Metering with variable speed
and variable stroke
pH indicator controller
2.6-3.1 mgd
0
150-150 tons/day
0
10
30" x ^8"
Basket
To surge tank
Convey to hopper, truck to
disposal
Mixed media, gravity flow
10
5 gpm/sq.ft.
Rate of flow control and loss
of head control
700 sq.ft.
58'
19'
12'
2'
5'6" over bed
20 gpm/sq.ft.
1-10 min. wash/day
Rate of flow controller
Two/Fi1ter
Circular, rotating surface
washers
180 gpm at 150 ps i
72
-------
Launders/Fi1ter
Mater ial
Filtration Media
Media Depth, each
Underdra i ns
Backwash Storage
Type
Capac i ty
Dimens ions
Diameter of sphere
Height above ground
Fill Pumps
C1ea rwe 11
Locat ion
Number of Units
Main Dimens ions
Length
Width
Operating Water Depth
Freeboard
Operating Volume
Construction
Pump Station
Number of Pumps
Capac i ty
Activated Carbon Columns
Number of Operating Units
Number of Standby Vessels
Total Number of Vessels
Hydraulic Loading
Contact Time (empty vessel)
Carbon Specification
Main Vessel Dimensions, each
Diameter
Carbon Depth
Freeboard
Backwash Rate for J>0 percent
Expans ion-
Design Pressure (ASME Code)
Materials of Construction
Backwash Pumps
Capacity, each
5
F i berglass
Micro-floc No. MF 186
equivalent
*4-2" with graded specif
grav i ty
Ceramic tile
Elevated tank
Pedestal sphere
250,000 gallons
J+0'
100'
2 at 2,000 gpm, each
Directly below filters
One
275'
25'
17.5' maximum
1.5'
900,000 gal Ions
Concrete
Three
17»500 gpm, each
lk single stage
Two
16
6 gpm/sq.ft.
29 mi nutes
8 x 30 mesh granular
23'
23'
7' expansion plus 2'
17 gpm/sq.ft.
150 ps i
Steel
Two
7,000 gpm
73
-------
Chlorination Facilities
Chlor inators
Number of Units
Capacity, each
Type
Evaporator
Chlorine Storage (ton containers)
Number of Units
Chlorine Contact Tank
Number of Units
Main Dimensions
Length
W i dth
Depth
Freeboard
Capacity, total
Detention Time
Iodine Feed Facilities
Tank Capacity
Pump Capac i ty
Materials of Construction
Pump Station (to swimming lake)
Number of Pumps
Capacity, each
Dechlorination Vessel
Flow
Rate
Number of Vessels
Hydraulic Loading
Carbon Volume
Main Dimensions
Diameter
Carbon Height
Freeboard
Activated Carbon
Three
^,000 lbs/day
Automatic (closed loop)
One
12 on floor
k on scale
One
275'
19'
IT.5' SWD
1.5'
700,000 gallons
20 minutes at 50 mgd
1,000 gallons
2 at h0 gph, each
Coated steel
Three
17.500 gpm
To boating lake
5 mgd
One
2 gpm/sq.ft.
1,810 cu.ft.
12'
16'
!+'
IV x 1+0 mesh granular
7^
-------
Pump Station (to boating lake)
Number of Pumps
Capacity, each
Pump Station (No. l)
Or ig in
Destination
Number of Pumps
Capacity, each
Pump Station (No. 2)
Orig in
Destination
Number of Pumps
Capacity, each
Pump Station (No. 3)
Origin
Dest ination
Number of Pumps
Capacity, each
Requirement
Carbon Regeneration
Spent Carbon Slurry Tank
Number of Units
Capacity
Materials of Construction
Slurry Pumps
Number of Units
Capacity, each
Stationary Dewattfring Screen
Number of Units
Capacity
Materials of Construction
Sump Capacity
Pump Capacity
Two
3.500 gpm
Swimming Lake
Reclamation Plant
Three
IT.500 gpm
Boating Lake
Reclamation Plant
Two
3.500 gpm
Anacostla River
Reclamation Plant
Two
3,500 gpm
Dry weather make-up
One
200 gal Ions
Steel
Two
200 gpm
One
200 gpm of 10 percent slurry
of 8 x 30 mesh activated
carbon
Stainless screen, steel tank
1,000 gallons
2 at 200 gpm, each
75
-------
Activated Carbon Regeneration Furnace
Number of Units
Type
Duty
Feed Material
Feed Rate
Ma i n D imens ions
D iameter
Number of Hearths
Other Equipment with Furnace
Fresh Carbon Storage Tank
Number of Units
Capacity
Main Dimensions
D iameter
Height
Carbon
Carbon Screw Feeder
Number of Units
Capac i ty
Peak
Average
Carbon Slurry Tank
Number of Units
Capacity
Slurry Pumps
One
Multiple Hearth
2k hours/day
Gravity-dewatered spent acti-
vated carbon
160,000 lbs/day
20'
S ix
Wet scrubber, drivers, duct-
work, induced draft fan,
combustion air fan, after
burner, cooling fan
One
9,600 cu.ft. or 2iK),000 lbs.
of carbon
23'
25'
8 x 30 mesh
One
200 Ibs/min.
10 lbs/min.
One
200 gal Ions
2 at 200 gpm, each
76
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
INRUENT AND STORAGE FACILITIES
G«IT WASHES
DRAWING 101
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
MULTI-MEDIA FILTRATION
DRAWING 103
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
ACTIVATED CARBON ADSORBERS 1 THRU 8
DRAWING 104
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
DETAIL PROCESS FLOW DIAGRAM
LAKE AREA DISTRIBUTION AND RECYCLE SYSTEMS
FISHING AND SOATING AREA
SWIMMING AREA
ANACOStIA RIVER
FISHING AND &OAHNG AREA
RECYCLE PUMPS
SWIMMING AREA
RECYCLE PUMPS
RIVER WATER
MAKE-UP PUMPS
DRAWING 106
-------
KINGMAN LAKE WATER RECLAMATION FACILITY
-------
SECTION VII
COST ESTIMATES
Capital Costs
Capital cost estimates have been prepared for various combinations of
surface storage and water reclamation plant capacities. All cost esti-
mates have been based upon current construction costs for similar fa-
cilities and, where applicable, upon preliminary quotations from equip-
ment manufacturers. A construction cost and escalation contingency of
15 percent has been included in all estimates. The estimates as pro-
vided, considering no significant deviation from current trends, should
be adequate through mid 1971. The Engineering News Record Construction
Cost Index of 1320 was used to update bid prices of current tunnel con-
struction projects in Chicago and California. Engineering, Surveying,
Soils and Foundation Studies, and Administrative Costs are included in
these cost estimates. Administrative costs are intended to account for
the Federal Government's administration of the Engineering and Construc-
tion contracts involved.
Table 15
Alternative Construction Costs
Water
Reclamation
Storage Plant
Capacity Capacity Cost
million gallons mgd
90 25 $33,440,000
175 25 38,540,000
175 50 42,900,000
235 25 43,680,000
235 50 48,060,000
Table 15 presents the total construction costs for the various alterna-
tives. The type of construction in all alternatives is similar, and
the differences in costs generally represent the differences in either
storage or treatment plant capacity. A breakdown of the estimated
total project costs for the 175 million gallon storage capacity-50 mgd
treatment plant capacity alternative is presented in Table 16.
Table 17 presents the estimate summary for the Tunnel Construction for
surcharge relief and combined sewer overflow storage. The cost for
mined storage has been estimated in a previous ROY F. WESTON Combined
Sewer Study for Washington, D.C.; mined storage for 242,000,000 gallons
was estimated at approximately $35,400,000 (ENR 1300), including the
associated shafts and pumping station; excavation unit cost was esti-
mated at approximately $19.00/cubic yard.
85
-------
Table 16
Preliminary Estimate
SUMMARY OF PROJECT COSTS1
175 MG Storage, 50 mgd Treatment Facility
Influent Channel and Diversion Chambers
Excavate and Backfill
Reinforced Concrete
P11 Ing
Hydraul Ic Gates
Metals
Sub-Total
Screen and Grit Chamber
Reinforced Concrete
Bui IdIng
Equipment
Degrlt Equipment and Flushing
Sub-Total
Storage Basin - Lake No. 1
Dredging
Excavate and Fill
Slurry Trench
Concrete Lining
Parking Roof
Ventilation System
Aeration System
Lighting
Sub-Total
Treatment Plant and Control Building
Excavation and Foundations
Reinforced Concrete
Gravity Filters and Elevated Storage
Carbon Columns
Pumps
Dechlorination Facility and Deodorize
Chemical Feed
Flash Mlx-Flocculatlon and Settling Equipment
Centrifuge Equipment
Sludge Storage Hopper
HeatIng-VentIlatIng and Plumbing and Interior
Sub-Total
Yard Piping
Pipe Installed
Pumping Station
Sub-Total
Lakes Nos. 2 and 3
Dredging
ExcavatIon and Fill
Sand • Lake No. 3
Dams
Bath House Facilities
Sub-Total
Site Work
Interceptor Sewer
Electrical
InstrunentatIon
Project Cost Sub-Total
Construction Contingency and Escalation - 15 percent
Sub-Total Construction Costs
Engineering, Surveying, Soils and Foundation Studies
Federal Government Contract Administration Costs
TOTAL PROJECT COSTS
205,000
2,545,000
750,000
585,000
35.000
$ 1,585,000
115,000
205,000
155,000
978,000
674,000
5.000,000
^98,000
3,894,000
50,000
668,000
88,000
1,221,000
2,695,000
2,011,000
3,150,000
218,000
100,000
151,000
313,000
630,000
20,000
525,000
1,020,000
130,000
2,100,000
120,000
50,000
500,000
940,000
3.920,000
2,060,000
$11,850,000
$11,304,000
$ 1,150,000
$ 3.790,000
100,000
730,000
2,000,000
400,000
$37,304,000
5,596.000
$42,900,000
2,200,000
100,000
^Engineering Hews Record Construction Cost Index = 1320
86
-------
Table 17
Estimated Cost Summary
Tunnel Construction for Surcharge Relief
and Storage
Tunnel at $8l8.00/LF1 $10,585,000
Pumping Station 2,383,000
Shaft Construction
Excavation 835,000
Concrete Work 2,855,000
Piping and Manholes l6l»-,000
Boring and Jacking 187, 000
Sluice Gates and Armor Plating 156,000
Sub-Total $17,165,000
Construction and Escalation Contingency 2,57^,000
TOTAL $19,739,000
1Based on actual costs of a 12-inch tunnel project at ENR 11^2, ad-
justed for increase in tunnel diameter to 30 inches and updated to
ENR 1320. Tunnel storage capacity (not including shafts) approxi-
mately 63,500 cu.ft.
87
-------
The excavation unit cost is a significant factor in any estimate of a
mined storage project, because excavation is the major cost item and
because the unit cost varies with the amount of excavation involved.
For example, in the study cited above, the unit excavation cost was esti-
mated over a range of $15 to $22 per cubic yard.
The cost of mined storage for volumes of 115, 225, and 285 million gal-
lons are shown in Table 18. These cost estimates will allow a direct
comparison with the surface storage facilities at the comparable volumes.
Table 18
1
Comparable Mined Storage Costs
Sub-Surface
Storage
Excavation
Unit Price
million gallons $/cubic yard
115
225
285
22.00
20.00
19.00
Cost of
Storage
millions
of dollars
13.9
27.2
34.4
millions
of dollars
Shafts and
Pump Station Total
millions
of dollars
6.2 20.1
6.2 33.4
6.2 40.6
-'-Including 15 percent Construction and Escalation Contingency.
Operating Costs
Annual operating costs have been prepared for the various alternatives.
As was noted with the construction costs, the annual operating costs for
the various alternatives are similar, and the differences generally repr
sent the differences in facility sizes.
Table 19
Alternative Annual Operating Costs
Water
Storage Reclamation
Capacity Plant Capacity Costs
million gallons mgd
90 25 $1,247,000
175 25 1,412,000
175 50 1,777,000
235 25 1,574,000
235 50 1,892,000
Table 19 presents the operating costs for all the alternatives considered,
and Table 20 is a breakdown of the estimate for the 175-million gallon
storage area, 50-mgd water reclamation facility.
88
-------
Table 20
Preliminary Estimate
SUMMARY OF ANNUAL OPERATING COSTS
175 mg Storage, 50 mgd Treatment Facility
Administration
Labor
Permanent Staff
Auxi1iary Staff
Maintenance
Structures
Mechanical
Piping
Electrical and
Instrumentation
Uti1i ties
Electrical
$280,000
$ 15,000
1% of $12,267,000
4% of $ 7,951,000
1% of $ 1,880,000
$122,000
$318,000
$ 19,000
2% of $ 2,488,000 = $ 50,000
8,000 x .7^6 x 24 X (150 + 0.6 x 210) x
$.010/KWH =
$ 100,000
$ 295,000
$ 509,000
$ 395,000
Chlorine
300
T/yr
X
$100/T = $ 30,000
A1 um
625
T/yr
X
$ 40/T = $ 25,000
Polymer
12.5
T/yr
X
$ 1/1 b = $ 25,000
Caustic
120
T/yr
X
$ 40/T = $ 5,000
Potassium Iodide
37.5
T/yr
X
$1.80/1b « $133,000
Make-up Carbon
Fuel Oil
Sub-Total
Operating Contingency @ 5%
Total
$ 218,000
$ 160,000
$ 15.000
$1,692,000
85.000
$1,777,000
Includes overhead and benefits.
2
Based on all power-consuming equipment operating simultaneously,
89
-------
SECTION VIII
SELECTION AND COST EFFECTIVENESS OF APPROPRIATE ALTERNATIVE
Selection of Storage Capacity and Reclamation Plant Capacity
The analysis and selection of the appropriate alternative involves the
measurement of the costs and benefits associated with each of the alter-
natives being considered. However, since 90 percent of the total capi-
tal cost of the project is directly related to pollution abatement, it
is reasonable that pollution abatement be the basis for selection of
the appropriate alternative.
The determination of the storage and treatment scheme with the highest
cost effectiveness can be made by analyzing the capi'tal cost expenditures
versus the corresponding percentage reduction of pollution, as shown in
Table 21.
Table 21
Cost Effectiveness of Kingman Lake Storage
and Treatment Alternatives
Storage
Bas In
Capacity
Water
ReclamatIon
Plant
Capacity
Effect Ive
Storage
Capacity
Total
Cost
Cap t tal
of
1-Year
Cost for each Percent Reduction
Organic Loading of Storm
In Millions of Dollars
2-Years 5-Years 15-Years
m1111ons
mgd
ml 11 Ions
ml 11 Ions
of gal Ions
of gal Ions
of dollars
90
25
115
1^.3
0.29
0.37
0.1*6
0.62
175
50
225
19.3
0.19
0.2k
0.32
0.1+2
235
50
285
22.1
0.22
0.22
0.30
0.1+0
As previously discussed, the relative difference among alternative storage
capacities in reducing annual organic loading is minor, suggesting that
the least-cost storage capacity is the attractive alternative. However,
in reference to the abatement of pollution, discussions in preceding
sections have established that significant consideration must be given
to the reduction of loadings of the intense sforms, and not just to the
reduction of annual loadings. Table 21 presents the cost effectiveness
of alternative storage basin-reclamation plant capacities, and shows
that the larger capacities are more effective, with reference to capital
costs, in reducing the loadings of the intense storms.
By considering both the reduction in the intense storm loading and in the
annual loading, the combination with the highest cost effectiveness is the
175-million gallon storage basin and the 50-mgd water reclamation plant.
Cost Effectiveness of Project
In dealing with multiple-purpose projects involving public investment in
such broad areas as water quality management and recreation, one is con-
fronted with the problem of elusive costs and non-quantifiable benefits.
However, some insight into the effectiveness of a multi-purpose project
is provided by defining the costs associated with single-purpose projects
satisfying the various individual goals of the project.
91
-------
The following discussion will present the various items which were con-
sidered as being directly or indirectly affected by this project and will
attempt to define quantitatively the relative values and cost effective-
ness of each. The obvious purpose of this is to compare the tentatively-
selected alternative with different methods of obtaining the same goals,
thus substantiating the desirability of the overall project.
The items which have been considered as having significant impact on the
Kingman Lake project are:
Pollution Abatement
Recreation (Swimming, Boating, and General Recreation)
Replacement (or Additional) Parking for R. F. Kennedy Stadium
Highway Construction
Pollution Abatement
Whereas pollution abatement has a significant intrinsic value, it is dif-
ficult to quantify in any terms other than the minimum cost of alternative
measures to attain the same goal. Separation of combined sewer areas had
been considered as an alternative to storage and treatment. However,
recent investigative efforts have indicated that the storm water dis-
charges are themselves a significant pollution source, and would require
eventual storage and treatment. A complete sewer separation for the entire
District would not be completed until after the year 2000, and would cost
an estimated $447,000,000-1-. (The Kingman Lake project involves about 25
percent of the District's present combined sewer area.)
Mined storage, with subsequent treatment at the Blue Plains Treatment Plant
during off-peak hours, is the least-cost alternative to the surface stor-
age and treatment concept presented in this report. Table 22 shows the
mined storage cost versus comparable Kingmar* Lake costs for treatment
and storage under the various alternatives (excluding the costs of the
parking roof and swimming facilities).
From Table 22 it is obvious that the cost for mined storage (with off-peak
treatment at Blue Plains) is significantly higher than the cost of the
Kingman Lake storage and treatment of comparable volumes of wastewater.
Recreation
Information relative to cost-benefit relationships for recreation has
been obtained from the U. S. Department of Interior National Park Service.
The recreational facilities envisioned as benefits of the reclamation of
land and water at Kingman Lake include water-oriented sports such as
swimming, boating, and fishing, and land-oriented recreational facilities
such as court games, scenic walks, picnic areas, etc.
"'"Board of Engineers study (1957) costs up dated from ENR index of 700 to
present value of 1,320.
92
-------
Table 22
Construction Cost Estimates
Mined Storage vs. Kingman Lake
Storage and Treatment
Mined Storage
Capacity
Cost
mill ions of
dollars
Kingman Lake
Capacity
Cost
mill ions of
dollars
115 mg 20.1
90 mg2 lk.3
25 mgd3
175 mg 16.0
25 mgd
225 mg 33.k
175 mg 19.3
50 mgd
235 mg 18.9-
25 mgd
285 mg
I4-0.6
235 mg
50 mgd
22.1
-includes cost of treatment at Blue Plains Plant.
2Capacity of storage basin, in millions of gallons.
3Capacity of water reclamation plant, in millions of gallons
per day.
93
-------
With an 8-hour turnover rate (required for disinfection) and a reclama-
tion plant capacity of 50 mgd, the swimming lake will have a maximum
daily capacity of 30,000 bathers on an effective swimming area of 11.3
acres. The facility will accommodate over 2,000,000 people annually,
based on a 90-day swimming season.
Boating, fishing, and land-oriented recreational facilities can accommo-
date as many as 200,000 persons per year (Fishing 30,000; Boating 30,000;
Wildlife Enthusiasts 20,000; Court Games 30,000; Picnics, scenic walks,
bicycle trails, etc. 90,000). In total, as many as 2,200,000 persons
would use recreational facilities at the Kingman Lake site. The National
Park Service has valued each visitor-day at $1.50. The corresponding
annual value of recreational facilities would then be $3,300,000. Assum-
ing park operational costs of $500,000 per year and current bond rates
of 8 percent (20 years), a capital expenditure for the above facilities
in the amount of $27,700,000 could be justified.
Replacement Parking
Replacement or additional parking can be provided for R. F. Kennedy
Stadium by constructing a structural covering over the proposed storage
basin. This parking roof will not only replace parking which will be
eliminated by the East Leg Freeway but will also provide an intangible
aesthetic benefit. The total surface area of the storage basin is ap-
proximately 670,000 square feet, of which 500,000 square feat above the
basin will be available for parking. The National Park Service has
valued such land at $6.25 per square foot ($1.25/sq.ft. for acquisition
and $5.00/sq.ft. for development). The parking facility could accommo-
date a maximum of 1,670 vehicles (145 per acre). Usage is estimated at
50 percent one hundred times per year plus 100 percent twenty times
per year. An annual revenue of $116,900/year could be expected at a
rate of $1.00 per space. Capital expenditures totaling $4,275,000
($3,125,000 for land and development; $1,150,000 from revenue) could be
justified.
The construction cost estimated for the parking cover over the storage
basin is $3,894,000 as shown on Table 16. It should be noted that the
only other area available for replacement parking is on the opposite
side of the Anacostia River, where bus transportation to and from the
Stadium would be required. No comparative cost is presented for this
parking alternative, but it is obvious that costs would be higher and
usage lower.
Highway Construction
The District of Columbia Department of Highways anticipates the construc-
tion of the East Leg Freeway along Kingman Lake in the near future. The
highway construction and Kingman Lake projects complement each other with
provisions for common construction. It has been envisioned that the high-
way would occupy approximately 170,000 square feet on the east side of
the basin cover. The structural system designed to support the storage
basin and the highway would obviate the necessity for a pile-supported
94
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highway foundation. Flood protection and interception of existing storm
drainage for the highway would be provided at the cost of the Department
of Highways. The costs common to both projects include: the highway
foundation supplied by Kingman Lake project $2,150,000^; interception
of storm drainage on the east side of Kingman Lake $840,000; and cost
of raising Burnam Barrier to 18.0 feet for flood control (not estimated
nor included in Kingman Lake Project Costs).
Tunnel Storage
While tunnel storage is not required as an element of the Kingman Lake
facilities, it is compatible with the long-range goals of the project.
The inclusions of tunnel storage in the long-range plans of the project
would, in addition to its primary function of surcharge relief, provide
a greater overall protection against pollution from combined sewer over-
flows. The addition of tunnel storage would increase total storage ca-
pacity to 310 million gallons, which corresponds to a return frequency
of approximately three years. An alternative relief sewer construction
plan under consideration by the District of Columbia would provide the
same surcharge relief, with no storage, at a significantly higher cost.
Summary of Cost Effectiveness
Table 23 presents a summary of cost effectiveness of the selected alter-
native as determined in this study.
2
Computed from average foundation costs estimated by D.C. Department of
Highways, (1.84 piles per linear foot x 2,300 l.f. x 70 feet per pile
x $9.00 per foot of pile).
95
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Table 23
Summary of Cost Effectiveness
of Selected Alternative
Items
Costs
Benefits
Diversion and Inlet Structures
Pollution Control Facilities
Recreation-^-
Common Highway Construction
Replacement Parking
$ 5,980,000
18,510,000
5,200,000
3,880,000
3,894,000
$33,400,0002
27,600,0003,4
3,880,000
4,275,000
Sub-Total
$37,464,000
$69,155,000
Construction and Escalation Contingency
Engineering and Administrative^
5,456,000
2,300,000
3,600,000
TOTAL COSTS AND BENEFITS
$45,320,000
$72,755,000
^"Including fish and wildlife.
^Minimum alternative cost (mined storage and treatment at Blue Plains).
Justifiable capital expenditures based on annual value of $3,300,000 minus annual
operating costs.
^Minimum alternative cost for neighborhood swimming facilities for 30,000 bathers = $60,000,000.
District of Columbia Department of Highways agrees that cost is their responsibility,
but does not necessarily agree with estimate.
^Engineering for above projects based on ASCE-recommended percentage fees.
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SECTION IX
ACKNOWLEDGMENTS
ROY F. WESTON gratefully wishes to acknowledge Mr. George A. Moorehead,
Chief of Systems and Planning, Department of Sanitary Engineering,
District of Columbia, Washington, D.C. for his efforts and assistance
in gathering data relative to the existing sewer system, records of
overflows in the Northeast Boundary Trunk Sewer, Weather Bureau data,
and a wealth of additional records and information which was not avail-
able from any other source.
Acknowledgment is made to Mr. John L. Paige, District of Columbia
Department of Highways and to Mr. Edwin Baker, Michael Baker, Jr.,
Harrisburg, Pennsylvania for their assistance in providing boring logs,
layouts, and proposed highway drawings for the vicinity of Kingman Lake.
Acknowledgment is made to Messrs. Manus J. Fish and Benjamin Howland
of the National Park Service, Department of the Interior, for guidance
and assistance in the planning of and establishing the relative values
of recreational facilities.
Acknowledgment is made to Mr. John F. Miller, Special Studies Branch,
United States Weather Bureau, for furnishing local climatolagical data
and for providing assistance in interpretation of these data.
Acknowledgment is made to Dr. Jack W. Hllf, Chief Designing Engineer,
Bureau of Reclamation, Department of the Interior, for guidance in
establishing a soils investigative program and assisting in the review
of soils data.
Acknowledgment is made to Mr. Allen Cywin, Chief of the Division of
Applied Science and Technology, Mr. William Rosenkranz, Chief of the
Storm and Combined Sewer Branch, and Mr. Darwin R. Wright, Project
Officer, all of the FEDERAL WATER QUALITY ADMINISTRATION, Department
of the Interior, for their interest and guidance during the course of
this project.
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Acknowledgment is made to the members of the staff of ROY F. WESTON who
participated in this project:
R. F. Weston, P.E., President
J. E. Germain, P.E., Vice President
W. D. Sitman, P.E. , Vice President
W. E. Hoover, P.E. , Vice President
V. T. Stack, P.E., Vice President
Client Services Division
Concept Technology Division
Engineering Design Division
Research and Development
Division
M. S. Neijna, P.E., Project Manager
Concept Technology Division
M. L. Woldman, P.E.
P. L. Buckingham, P.E
J. K. Kane
J. A. Lee
D. N. Bibbo, P.E
Engineering Design Division
R. E. Coleman, P.E.
G. W. Orr
T. E. Taylor
R. B. Geissinger
T. C. Agetone
W. J. Buttner
G. C. Torboss
P. J. Marks Research and Development
J. W. Davison Division
C. J. Cahill
J. A. Rohr
J. C. Watt
J. W. Hitzelberger Planning & Systems Division
J. C. Allison
D. W. Syphard
Special acknowledgment is made to the Technical Editing, Report Preparation,
and Duplicating Groups without whose assistance and perserverance this
report could not have been completed.
J. L. Simons, Technical Editor D. Rimel
J. P. Jarosh P. Warihay
N. McVey R. Towson
J. Smith J. Day
98
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SECTION X
REFERENCES
1. "Preliminary Engineering and Applied Research Study, Washington,
D.C. Combined Sewer System", ROY F. WESTON report, February, 1970.
2. "Proposed Comprehensive Plan for the Nation's Capital", National
Capital Planning Commission, February, 1967.
3. "Report on Planning Studies, Northeast Boundary Relief Sewer",
Report No. 67-56 R, Burns and McDonnell Engineering Company,
Engineers-Architects-Consultants, Kansas City, Mo., 1968.
4. Board of Engineers Report to the District of Columbia Department
of Sanitary Engineering on Improvements to the Sewerage System,
February 28, 1957.
5. FWQA Contract No. 14-12-403.
6. "The Climatic Handbook for Washington, D.C.".
7. J. C. Merrell et al, "The Santee Recreation Project", FWPCA
Publication No. WP-20-7, 1967.
8. A. P. Black et al, "Use of Iodine for Disinfection", Journal
American Water Works Association, November, 1965.
9. A. P. Black et al, "Iodine for the Disinfection of Water", Journal
American Water Works Association, January, 1968.
10. A. P. Black, "Swimming Pool Disinfection with Iodine", Water and
Sewage Works, July, 1961.
11. "Water Quality Criteria", National Technical Advisory Committee
to the Secretary of the Interior, FWPCA, Washington, D.C., April,
1968.
12. J. A. Salvato, Environmental Sanitation. John Wiley and Sons, Inc.
New York, 1958.
13. "Outdoor Recreation Space Standards", Bureau of Outdoor Recreation,
Washington, D.C., April, 1957.
14. "Rainfall Frequency Analysis of the United States", U.S. Weather
Bureau Technical Paper No. 40, May, 1961.
15. "Local Climatological Data, Annual Summary with Comparative Data,
1968, Washington, D.C.", National Weather Center, Asheville,
North Carolina, 1969.
99
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16. "Appraisal of Granular Carbon Contacting, Phase III", Robert A. Taft
Research Center Report No. TWRC-12, May, 1969.
17. "Synthetic Storm Pattern" -C.J. Kiefer and H. H. Chu, Journal of
Hydraulics Division, ASCE, Vol. 83, August 1957.
18. "Surface Runoff Determination from Rainfall Without Using Coefficients"
W. W. Horner and S. W. Jens, Transactions, ASCE, Vol. 107, 1942.
19. "The Hydrology of Urban Runoff" - A. B. Tholin and C. J. Kiefer,
Journal of the Sanitary Engineering Division, ASCE, Vol. 85, March
1959.
20. "Design and Construction of Sanitary Sewers" - ASCE MOP No. 37, New
York, 1960.
21. "Report to the District of Columbia Department of Sanitary Engineering
on Improvements to Sewerage System" - Board of Engineers, February
28, 1957.
22. G. E. Glover and P. M. Yatsuk, Microstraining - With Ozonation or
Chlorination - Of Combined Sewer Overflows, preliminary draft of
final report to FWPCA under Contract No. 14-12-136 by Cochrane
Division, Crane Company, King of Prussia, Pennsylvania.
23. Cornell, Howland, Hayes and Merryfield Consulting Engineers and
Planners, Rotary Vibratory Fine Screening of Combined Sewer Overflows,
rough draft of report to FWPCA under Project No. 11020 FDD, Corvallis,
Oregon, November 1969.
24. Richard E. Speece and Jack L. Adams, U-Tube Oxygenation Operating
Characteristics» Technical Report No. 45, Engineering Experiment
Station, New Mexico State University, Las Cruces, New Mexico (May 1968).
25. Huibers, D. T. A., McNabney, R. and Halfon, A., "Ozone Treatment of
Secondary Effluents from Wastewater Treatment Plants", Report No.
TWRC-4, Robert A. Taft Water Research Center, FWPCA, U.S. Department
of Interior, Cincinnati, Ohio (April 1969).
100
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SECTION XI
APPENDICES
Appendix Page
A TREATMENT PROCESS INVESTIGATION AND CONFIRMATION 103
Project Scope and Objectives 103
Experimental Program 103
Program Implementation 104
Experimental Results 106
Conclusions 114
Tables A-l through A-6: Multi-Media Filtration 115-
Studies.. 120
Table A-7: Comparison of Multi-Media and Fiberglass
Filtration 121
Table A-8: Activated Carbon Adsorption 122
Table A-9: Phosphorus Removal 123
Table A-10: Provisional Algal Assay Study 124
Table A-ll: Thickened Sludge Dewatering. 125
Figure A-l: Laboratory Multi-Media Filter Column 126
Figure A-2: Multi-Media Filtration - Activated Carbon
Adsorption Pilot Plant Flow Diagram. 127
Figure A-3: Laboratory Fiberglass Filter Column 128
B APPLICATION OF TUNNEL STORAGE TO NORTHEAST BOUNDARY
TRUNK SEWER 129
General Concept 129
Geological Investigation Program 130
Data Collection 130
Subsurface Investigation Program 130
Laboratory Testing 132
Table B-l: Estimate Cost Summary 133
Figure B-l: General Tunnel Location 134
Figure B-2: General Scheme-Vertical Shaft 135
C PRELIMINARY SOIL AND FOUNDATION INVESTIGATION
(Appended in Separate Volume) 137
D INVESTIGATION OF RAINFALL-RUNOFF RELATIONSHIPS 139
Methodology 139
Results - Volume of Overflow 144
E LITERATURE EVALUATION OF ALTERNATIVE WASTEWATER
TREATMENT PROCESSES 145
Micros training of Combined Sewer Overflows 145
U-Tube Aeration 147
Ozonation as a Unit Process for Treatment of
Combined Sewer Overflows 148
101
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APPENDIX A
TREATMENT PROCESS INVESTIGATION AND CONFIRMATION
Project Scope and Objectives
The primary objectives of the Process Development Studies were as follows:
1. Conduct experimental studies to demonstrate the water
quality of the effluent from multi-media filtration-
activated carbon adsorption treatment of combined
sewer overflow.
2. Determine and demonstrate a process which can pro-
vide the degree of treatment necessary to meet water
quality objectives of the Kingman Lake Recreational
Area Project.
3. Perform a comparative evaluation of multi-media
filtration versus varying density fiberglass fil-
tration.
Experimental Program
A program was prepared to provide 30-day continuous operation of an ex-
perimental unit utilizing filtration, activated carbon adsorption, and
disinfection processes. Investigation of multi-media filtration of
combined sewer overflows was directed toward confirming the effective-
ness of this treatment, and to determine if a filter effluent could
be produced which would be acceptable for application on a granular
activated carbon bed. Activated carbon treatment of the effluent of
multi-media filtration was studied experimentally to determine if
certain BOD water quality criteria could be achieved. Disinfection by
chlorination was included in the demonstration study as a means of
achieving the bacteriological and viral requirements.
Samples of raw sewage and other wastewaters were collected and mixed
to provide synthetic samples containing pollutants in concentrations
approximating those expected in the combined sewer overflows from the
Northeast Boundary Trunk Sewer. Treatment of a batch of synthetic sam-
ple was evaluated for a three-day continuous period. This was followed
by a four-day investigation of both recycle of treated wastewater and
makeup using relatively clean water samples. The first-stage operation
of multi-media filtration provided an effluent which was used as the
feed to the activated carbon adsorption columns, followed by chlorina-
tion to produce a final effluent. To provide comparative information,
the fiberglass filtration unit was operated simultaneously with multi-
media filtration columns for several Investigative trials.
103
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Program Implementation
1. Wastewater Samples
The wastewater samples were obtained from the following three sources
in 600- to 2,000-gallon quantities:
a. Influent to the primary treatment facility at the West Chester,
Pennsylvania Sewage Treatment Plant.
b. Overflow from the West Chester, Pennsylvania Reservoir.
c. Anacostia River water from the Kingman Lake area.
Mixtures were prepared of raw sewage and reservoir water, or of raw
sewage with Anacostia River water. The 1,200-gallon batch mixtures
were made up of approximately 50 percent raw sewage, with the addi-
tion of finely ground silt. To simulate make-up water, several sam-
ples consisting only of reservoir water or Anacostia River water were
prepared. The samples were stored in tanks with continuous mixing
and at a controlled temperature of 20°C for periods of three to four
days during the experimental runs.
2. Description of Pilot-Scale Apparatus
The multi-media filtration demonstration unit was constructed with
a two-inch diameter Pyrex glass column eight feet in length. The
three types of filter media used were anthracite, sand, and garnet
of sizes and arrangement shown in Figure A-l. A centrifugal pump was
used to supply the forward flow, which was maintained at a constant
rate with a flow regulator valve. Flow was measured by the use of
a graduated cylinder and stopwatch. The pressure measurements were
obtained as differential measurements across the filtration bed.
Backwashing of the filter bed was accomplished with tap water pump-
ed by a small centrifugal pump, and the flow rate was measured by
a rotameter.
The effluent of the multi-media filter was collected by gravity in
a 10-gallon plastic tank provided with an opening for overflow to
waste. A positive displacement pump transferred a portion of this
filtrate to the activated carbon unit.
The second-stage treatment by activated carbon adsorption consisted
of four two-inch diameter, Pyrex glass, vertical columns eight feet
in length, connected In series by one-half inch tubing with appro-
priate valves. Head loss was determined as differential measure-
ment across the activated carbon bed in each column. Granular car-
bon, size 4 x 12, was placed in the columns for the first phase of
the project, and was replaced with 12 x 40 size carbon for the sec-
ond phase. Sample ports were provided at the base of each column,
and at carbon depths of 6, 24, and 42 inches.
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The effluent of the activated carbon unit flowed by gravity to a
ten-gallon plastic tank, where disinfection was accomplished by
feeding a chlorine solution by siphon from a holding tank. The
flow diagram for the combined multi-media filtration and activated
carbon adsorption demonstration unit is shown on Figure A-2.
The fiberglass filtration unit was constructed of Plexiglas to
form a four-inch square, eight-foot high column. Provisions were
made to insert four fiberglass plugs of varying densities into
the column. An eighteen-inch bed of size 2.0 trail, anthracite was
placed in the column above the plugs of fiberglass. Ports were
available above and below each plug to determine head loss by dif-
ferential measurement. Pumping of samples through the unit and
backwashing were accomplished with the same facilities used for
the multi-media filtration unit. The configuration of the fiber-
glass plugs of various densities is shown in Figure A-3.
3. Operating Procedures
a. Multi-Media Filtration
Several filter runs were made on each 1,200-gallon batch
of wastewater. Each sample was pumped down-flow through
the filter bed at a constant feed rate over a range of 5
gpm/sq.ft. to 20 gpm/sq.ft. A filter run was defined as
that time period for wastewater application until exces-
sive head loss indicated the need for backwash. Composite
samples of feed and of effluent were taken during the fil-
ter run; these were analyzed for 5-day Biochemical Oxygen
Demand, Chemical Oxygen Demand, and Suspended Solids.
Backwashing of the filter was accomplished with tap water
(and air-scour) at a rate sufficient to expand the filter
bed from twelve to eighteen inches; this backwash rate was
maintained until the backwash effluent ran clear for ten
minutes.
b. Activated Carbon Treatment
The effluent from the multi-media filter was pumped through
the activated carbon columns at a constant rate of 4 gpm/
sq.ft. An attempt was made to transfer to the carbon col-
umns only that filtrate which was reasonably free of sus-
pended solids.
Measurements were made of head loss across each column.
Eight-hour composite samples were collected of feed to the
unit, and of effluent from the final column. These samples
were analyzed for 5-day Biochemical Oxygen Demand, Chemical
Oxygen Demand, and Suspended Solids.
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A Union Carbide Total Carbon Analyzer was used for contin-
uous monitoring of the total carbon concentration at eight
sample points on the columns. Separate feed and effluent
samples were acidified and aerated, to determine inorganic
carbon as the difference in total carbon before and after
treatment.
c. Disinfection
A chlorine solution prepared from HTH solution hypochlorite
was allowed to flow by a siphon arrangement into a final res-
ervoir at a rate which insured a fifteen-minute detention time.
A chlorine residual of 0.1 to 0.2 mg/L was maintained in the
final effluent, and samples were composited for bacteriolog-
ical examinations to determine total coliform and fecal con-
form concentrations.
Experimental Results
1. Multi-Media Filtration
a. No Pretreatment
A 1,200-gallon mixture of wastewaters was prepared from 600
gallons of raw sewage influent to the primary treatment fa-
cilities of the West Chester, Pennsylvania Sewage Treatment
Plant, combined with 600 gallons of overflow from the West
Chester Reservoir. Finely-ground silt was added to increase
the suspended solids concentration. This wastewater mixture
was used for four filter runs over a three-day period. The
application rate to the multi-media filter was 5 gpm/sq.ft.
The filter bed was backwashed after each run.
The summary of analyses of the composite samples shown in
Table A-l shows COD removals of 59-74 percent, BOD removals
of 52-78 percent, and suspended solids of 60-87 percent. How-
ever, the degree of suspended solids removal was not satis-
factory because of rapid accumulation of the residual solids
on the activated carbon bed in the No. 1 column when the fil-
ter effluent was fed to the activated carbon treatment unit.
The suspended solids remaining in the filter effluent were
inorganic in nature and consisted of a very fine silt, 10
microns or less in size.
b. Pretreatment of Wastewater by In-Line Flocculant Addition
A mixture of raw sewage and reservoir water plus silt com-
prised the batches of synthetic combined sewer overflow
sample for this evaluation. Several short filter runs at
5 gpm/sq.ft. were made with the addition of 25 mg/L of alum
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introduced into the feed line to the filter. This alum dos-
age produced a large floe which quickly formed a layer on the
surface of the anthracite. A rapid increase in head loss re-
sulted.
Several additional runs were made with smaller alum dosages on
a similar batch of wastewater. Longer filter run times were
9bserved; however, as indicated on Table A-2, no significant
improvement in removals of COD, BOD5, or suspended solids can
be attributed to the in-line addition of alum.
Dow C-31 polyelectrolyte at a dosage of 0.1 mg/L was pumped
into the feed line for one run; this did not improve the fil-
tration results.
Treatment of Recycle Water (River of Lake Water)
Watier obtained from the overflow of the West Chester Reservoir
was pumped through the filtration unit at a rate of 10 gpm/sq.
ft. for approximately three days to simulate the wastewater
flow to the proposed treatment facility during periods of re-
cycling water from the proposed swimming and fishing lakes.
This was done to demonstrate system performance when operation
is changed from higher to lower loadings of pollutants. There
were no problems in filtration of the cleaner sample of res-
ervoir water. Table A-3 shows that the percent removals of
COD, BOD5, and suspended solids were lower than results from
previous filter runs on synthetic combined sewer overflow sam-
ples; effluent concentrations were lower too.
Pretreatment by Alum Flocculation
Chemical flocculation was studied because examination of the
effluent of the Multi-Media Filter showed that residual solids
were small, 10 microns or less in diameter. These suspended
solids accumulated to a significant degree on the activated
carbon and caused some head loss across the first column; thus
it was decided to remove as much suspended matter as possible
before application on the Multi-Media Filter.
A series of jar-test flocculation studies indicated good clari-
fication of this mixture by the addition of 50 mg/L of alum
during rapid mix followed by five minutes of flocculation.
Fifteen minutes of settling time produced a good supernatant.
Two batches, composed of raw sewage and 400 gallons of reservoir
water with silt added, were mixed for this test. While each
batch was in the holding tank, an alum dosage of 50 mg/L was
applied, followed by rapid mixing and thirty minutes of settl-
ing. Alum addition and sedimentation reduced the COD of one
batch from 160 mg/L to about 40 mg/L. Likewise, this treat-
ment reduced BOD from 32 mg/L to 3 mg/L, and the suspended solids
from 580 mg/L to 14 mg/L.
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The supernatant was pumped off to a separate tank
and was used as the feed to the multi-media filter
at rates of 5 gpm/sq.ft., 10 gpm/sq/ft. and 15
gpm/sq,ft. Table A-4 shows the results of filtra-
tion of the supernatant. The average percent re-
movals across the two operations of alum pretreat-
ment and multi-media filtration were: COD-76 per-
cent, BOD5-9I percent, and Suspended Solids-99 per-
cent.
Anacostia River Water Sample
A 2,000-gallon sample of Anacostia River water was
collected from a location in the Kingman Lake area,
and transported by tank truck to the ROY F. WESTON
laboratories in West Chester, Pennsylvania. Analy-
ses of this water identified the characteristics as
26 mg/L COD, 5 mg/L BOD5, and 165 mg/L Suspended
Solids.
A filter run was made without pretreatment of the
samples at a rate of 5 gpm/sq.ft. Removals of 37
percent COD, 10 percent BOD, and 71 percent Sus-
pended Solids occurred. However, the very fine
silt escaped filtration, and resulted in a turbid
effluent. This filtrate was similar to that pro-
duced by filtration of a synthetic combined sewer
overflow sample without pretreatment, and was not
considered satisfactory as feed to the activated
carbon pilot unit.
Anacostia River Water—Alum Pretreatment
A series of jar tests on the Anacostia River water
sample indicated that the wastewater could be ef-
fectively treated with a dosage of 50 mg/L of alum,
or with lower dosages of alum (10 mg/L-20 mg/L) com-
bined with a polyelectrolyte dosage of 0.5 mg/L of
Hercules Reten 210. Ferric chloride treatment was
evaluated by jar tests, and produced satisfactory
flocculation, but was less effective in the removal
of fine silt.
One thousand gallons of the Anacostia River sample
were treated in the tank with 50 mg/L of alum.
After settling, the supernatant was pumped to the
multi-media filter at rates of 10 and 20 gpm/sq.ft.
Alum treatment reduced COD to 10 mg/L, BOD to less
than 2 mg/L, and Suspended Solids to 14 mg/L.
Table A-5 summarizes the multi-media filtration
data. Total reduction in COD by alum treatment
followed by filtration was 65 percent, BOD5 75
percent, and Suspended Solids 98 percent.
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g. Synthetic Mixture of Anacostia River Water and
Domestic Wastewater
A mixture of raw sewage, silt, and Anacostia River
water was prepared. This mixture was treated with
100 mg/L of alum, which reduced COD from 14A mg/L
to 62 mg/L, BODc from 67 mg/L to 19 mg/L, and Sus-
pended Solids from 522 mg/L to 58 mg/L.
Table A-6 shows the results of multi-media fil-
tration of the supernatant after alum flocculation
and sedimentation. The combined process of alum
pretreatment followed by filtration effected an
overall removal of 70 percent of COD, 82 percent
of BOD5, and 97 percent of Suspended Solids.
A second batch was prepared similar to the first,
but with more silt. As before, filtration fol-
lowed alum treatment at a dosage of 100 mg/L.
The results were similar, with an overall re-
ductions of 73 percent COD, 92 percent BOD5,
and 99 percent Suspended Solids.
2. Fiberglass Filtration
A comparative evaluation was made of the fiberglass filter and a
four-inch diameter multi-media filter. Both filters were operated
simultaneously at a flow rate of 5 gpm/sq.ft., with a feed of a
synthetic combined sewer overflow sample without alum pretreatment.
A considerably longer run time was permitted by the fiberglass fil-
ter. After one hour, the head loss across the multi-media filter
was excessive because of accumulated solids; in comparison, the
fiberglass filter allowed a nine-hour run. Table A-7 shows that
the percent removals of COD and BOD were in the same range, while
the suspended solids reduction by fiberflass filtration was much
greater. For example, this test achieved a 98 percent removal
compared to the 85 percent solids removal of the multi-media
filter.
Backwashing of the fiberglass filter was accomplished with tap
water and air at 40 psi. This high backwashing pressure was
necessary to dislodge the solids trapped in the fiberglass plugs,
but still did not adequately clean the unit. Subsequent runs at-
tempted through these same fiberglass plugs were of very short
duration because of a rapid increase of head loss across each
of the plugs. In fact, the initial head loss of the pilot unit
across the bed after backwashing was higher than when the plugs
were new.
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3. Activated Carbon Treatment
The initial application of activated carbon adsorption was to the
effluent from multi-media filtration without alum pretreatment.
The carbon columns were charged with a relatively coarse carbon
to determine if any difficulties would be encountered in treat-
ing an effluent containing as much as 125 mg/L of very fine
silt. Satisfactory removals of COD, BOD5, Total Carbon, and Total
Organic Carbon were obtained; however, a significant amount of sus-
pended solids accumulated in the first column and eventually caused
too high a head loss. This trial established the need to use
alum pretreatment to produce an effluent containing a low concen-
tration of suspended solids. Alum pretreatment, settling, and
multi-media filtration, reduced concentrations of suspended solids
to a level (3-15 mg/L) which did not cause too high a head loss in
the first carbon column. A pumping rate of 4 gpm/sq.ft. was main-
tained during the entire pilot plan study, and the columns were
charged with 12 x 40 mesh carbon. The average concentrations of
COD, BOD, suspended solids, to1;al carbon, and total inorganic
carbon in the feed and effluent are shown in Table A-8.
At the time of changeover from the treatment of a synthetic waste-
water sample to a sample containing considerably lower concentra-
tions of pollutants (reservoir water), an initial elutriation of
adsorbed materials from the activated carbon bed was observed.
The physical redistribution was brief, and did not occur again
throughout the remainder of the run.
4. Disinfection
The disinfection of the final effluent from the Activated Carbon
Pilot Unit was achieved by the addition of a dilute hypochlorite
solution in a ten-gallon holding tank, at chlorine dosage rates
of 1.0-5.0 mg/L. A detention time of fifteen minutes and a total
chlorine residual of 0.1-1.0 mg/L in the final effluent were main-
tained. Bacteriological examinations of eight-hour composite sam-
ples of the effluent were accomplished by the Millipore Filter
Technique to determine the colony count of total coliform and
fecal coliform.
5. Phosphorus Removal
The experimental studies included a sampling and analytical pro-
gram to determine the effectiveness of the demonstration unit for
the removal of phosphorus compounds. As indicated in Table A-9 the
synthetic wastewater samples were found to contain from 23 mg/L to
30 mg/L of total phosphate. Table A-9 also shows that alum floccu-
lation of these wastewaters produces total phosphate reductions of
from 61 percent and 90 percent at dosages of 50 mg/L and 100 mg/L
of alum. Further phosphorus removal through the multi-media filter
was not significant. Some additional reduction was observed by
110
-------
filtration ox absorption on the activated carbon. Elutriation
of the phosphate from the carbon bed was evident when a synthetic
wastewater run was followed by reservoir water or river water.
A summary of the algal growth study is presented in Table A-10.
6. Sludge Dewatering
The settling and thickening characteristics of the sludge obtained
from the alum flocculation treatment were good. The floe was large,
and settled rapidly to produce a clear supernatant in 20 to 30
minutes. One-liter thickening tests of the settled sludge with
slight agitation by stirring^ showed that a settled sludge contain-
ing 4.5 percent solids (dry weight) can be thickened to approximately
9.0 percent solids in one hour.
The sludge from the backwash of the multi-media filter was evaluated
at 0.4 percent solids (dry weight) by one-liter settling tests.
Within 20 minutes, the sludge had settled to 15 percent of the orig-
inal volume to produce a sludge of approximately 2.7 percent solids.
Sufficient sludge of this type was not available for thickening or
dewatering tests.
The thickened sludge produced by alum flocculation was- used for de-
watering studies, which included an evaluation of vacuum filtration
by the Buchner Funnel technique. Lime, ferric chloride, and several
polyelectrolytes were investigated as sludge conditioners. The
sludge alone dewatered poorly, and none of the conditioners produced
a satisfactory improvement In the filtration rates. The specific
resistance data obtained from the Buchner Funnel evaluation are sum-
marized in Table A-ll.
A limited evaluation of the dewatering of the sludge by centrifuge
indicated that there could be difficulty in obtaining a satisfactory
cake. In our best judgment (within the limitations of the project
scope and the time allotted), ten centrifuges would handle the sludge
adequately. In the engineering design phase, the sludge dewatering
problem will be subject to a more critical analysis, and the result
probably will be to specify alternative dewatering facilities ex-
pected to be less costly than the. ten centrifuges involved in the
current preliminary design and cost estimates.
Sludge cooking at high pressures and temperatures indicated a sig-
nificant reduction in the specific resistance of the sludge to vacuum
filtration. Quantities of thickened sludge were subjected to various
pressures and high temperatures (indirect heat) for different periods
%y a standard ROY F. WESTON device designed to stir the contents of a
1-liter cylinder at 1/6 rpm.
Ill
-------
of time. The cooked sludge was submitted to further evaluation by
the Buchner Funnel Technique in order to determine specific resis-
tance. Table A-ll shows that this treatment at 82°C and 290 psi
pressure for 60 minutes was able to change the specific resistance
of the thickened sludge from 5,350 x 10^ sec.^/gm with untreated
sludge to 61.6 x 10^ sec. /gm after cooking.
7. Provisional Algal Assay Study
An experimental study was performed to estimate the effect on algal
growth in an environment consisting of various wastewater samples
collected before treatment, and at various stages of treatment
through the pilot plant. Samples of raw sewage, synthetic storm
overflow mixture, Multi-Media Filter effluent, and activated carbon
treatment effluent were evaluated.
The provisional algal assay procedure developed by the Joint
Industry/Government Task Force on Eutrophication was the procedure
used throughout this study. Procedure No. 1, a bottle test, is
the method by which test algae are added to the sample in the labor-
atory under controlled conditions, and growth is determined by
assaying the algal crop on a daily schedule. Table A-10 summarizes
the results obtained by this procedure.
It appears from an examination of these data that the phosphorus
concentration may have a limiting effect on algal growth in the
reservoir water and in Anacostia River water. However, other
factors such as sample clarity, with greater light penetration,
may have influenced the growth in the samples with higher turbidity.
The algal growth itself created a very turbid mixture, brilliant
green in color. A factor to consider in interpretation of these
results is that considerable time (three weeks under refrigeration)
elapsed between actual sampling time and the start of the algal
study.
The conclusion drawn from this brief study is that the effluents
from the pilot plant, when treating synthetic wastewater samples,
resulted in as great as or greater algal production than the
standard nutrient solution. However, when simulated recycle
water was run (reservoir water or Anacostia River water), con-
siderably less growth was observed.
8. Virus Study
In order to determine the effects on a particular virus by the
proposed treatment, a procedure was developed and implemented
concurrently with the pollutant removal experimental studies.
112
-------
A synthetic combined sewer overflow sample was prepared from 250
gallons of raw sewage and 250 gallons of Anacostia River water.
This mixture was maintained at a temperature of 30°C and con-
stantly mixed. Eighty milliliters^ of Type 1, live polio virus,
obtained from Wyeth Laboratories, in a 0.85 percent saline solu-
tion was added to this mixture. A mixing period of 15 minutes
was allowed before treatment of the entire contents of the tank
by 100 mg/L alum. The contents were mixed rapidly for five
minutes, the floe allowed to settle for thirty minutes, and
the supernatant pumped to another tank. This supernatant was
fed to the Multi-Media Filter at a rate of 5 gpm/d'q.ft. and to
the Activated Carbon columns at 4 gpm/sq.ft. The final effluent
was chlorinated at 1.0 mg/L.
An additional twenty milliliters of the polio virus was added
twenty-four hours later to the supernatant sample, and the chlorine
dosage was increased to 5.0 mg/L at this time.
Samples were collected of the initial mix containing polio virus,
the supernatant after alum treatment, effluent from the Multi-Media
Filter, effluent from the Activated Carbon Pilot Unit, and of the
final effluent after chlorination. These samples were delivered
to Microbiological Associates, Bethesda, Maryland for examination.
Results of these tests indicated no virus activity even in the
sample of the untreated wastewater-rinses mixture. The conclusions
drawn from the virus test are:
a. The virus was inactivated in the wastewater medium.
This is confirmed.
b. The testing procedure was not sufficiently sensitive
to detect the virus.
9. BOD5 Removal During Storage
The mixtures of raw sewage and reservoir water which did not receive
the alum flocculation treatment were stored in tanks for three-day
periods. The contents were mixed mechanically to a degree which
kept the solids suspended and which maintained an aerobic condi-
tion. The temperature was controlled at 20°C in the mixture. Fre-
quent analyses for BOD5 were conducted during this period, and a
plot of BOD5 vs. time indicates approximately 50 percent BOD5 re-
moval for three days storage under these conditions.
4
Each milliliter contains 200,000 to 500,000 tissue culture infective
doses (105-3 to 105*7 TCID50).
113
-------
Conclusions
1. Treatment of a synthetic combined sewer overflow wastewater by multi-
media filtration, followed by activated carbon treatment and disin-
fection, can produce an effluent which meets the water quality criteria
objectives outlined in this report, if the wastewater is pretreated
by chemical flocculation and clarification.
2. Pretreatment by in-line chemical addition as an aid to filtration be-
fore the multi-media filter was not successful with the chemicals
and at the dosages tested.
3. No significant problems were observed during treatment of simulated
recycle of water from the proposed swimming and boating-fishing areas.
Some elutriation of adsorbed materials occurred briefly when treatment
of a wastewater containing greater levels of pollutants was followed
by simulated recycle water.
4. Pretreatment of Anacostia River make-up water by chemical flocculation
is necessary to assure removal of fine silt before multi-media filtra-
tion.
5. Chlorination of the final effluent of the experimental unit demonstrated
that the water quality objectives concerning total coliform and fecal
coliform can be achieved.
6. Filtration through fiberglass was shown to be an effective method
of solids removal; however, considerable difficulties are experienced
in effectively removing the accumulated solids by backwashing.
7. Significant phosphorus removal occurs during the pretreatment of the
wastewater by chemical flocculation. Some additional reduction of
phosphorus was obtained by treatment thorugh the demonstration unit;
however, elutriation of the retained phosphorus was evident.
8. Algal production from wastewater nutrients was not inhibited by
treatment through the demonstration unit.
9. The dewatering characteristics of the sludge produced by chemical
flocculation with alum were poor. None of the sludge conditioners
evaluated produced a satisfactory improvement in dewatering by
vacuum filtration.
114
-------
Table A-l
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Multi-Media Filtration
Synthetic Combined Sewage Sample
No Pretreatment
COD
BOO
Suspended Solids
Batch
Run
Percent
Percent
Percent
Date
Number
hi umber
Flow Rate
Feed
Effluent
Removal
Feed
Effluent
Remova1
Feed
Eff1uent
Remova1
gpm/sq.ft.
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
3-6-70
1
1
5
172
71
59
37
16
56
504
64
87
3-6-70
1
1
5
152
60
6o
29
14
52
500
80
84
3-7-70
1
2
5
130
to
69
36
8
78
498
64
87
3-7-70
1
2
5
130
kO
69
17
8
53
392
79
80
3-8-70
1
3
5
160
45
7i+
19
7
63
526
139
73
3-8-70
1
3
5
170
50
70
21
5
76
560
86
85
3-9-70
1
3
5
130
50
61 '
19
7
63
369
150
60
3-9-70
1
h
5
116
14-6
60
22
7
68
436
126
71
-------
Table A-2
Kingman Lake
Federal Water .Quality Administration
Washington, D.C.
Multi-Media Filtration
Synthetic Combined Sewage Sample
Pretreatment by In-line Filter-Aid Addition
COD
BOD
Suspended Sol ids
Date
Batch
Number
Run
Number
Flow Rate
A1 urn
Feed
Eff1uent
Percent
Remova1
Feed
Eff1uent
Percent
Remova1
Feed
Eff1uent
Percent
Remova1
gpm/sq.ft.
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
3-11-70
3
1
5
25
200
81
59
67
k-2
^7
320
uo
88
3-12-70
3
2
5
25
168
69
59
5^
21
61
310
20
9k
3-18-70
5
1
5
¦5
137
73
k6
29
15
kQ
266
66
75
3-19-70
5
2
5
10
105
51+
k9
20
8
60
228
38
83
3-20-70
5
3
5
15
11*
52
6^
22
7
68
316
75
76
lj--llj—70
3
3
5
0.11
153
6U
58
2k
11
5^
3^1+
62
82
"""Dow C-31 Polyelectrolyte.
-------
Table A-3
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Millti-Media Filtration
Reservoir Water Sample
No Pretreatment
COD
BOD
Suspended Sol ids
Run
Percent
Percent
Percent
Date
Number
Flow Rate
Feed
Eff1uent
lemova1
Feed
, Eff1uent
Remova1
Feed
Eff1uent
Remova1
gpm/sq.ft.
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
3-14-70
1
10
13.0
14.0
—
2.1
1.1
48
29
10
65
3*15-70
1
10
10.8
11.2
—
1.4
1.2
15
12
8
33
3-15-70
1
10
10.8
9.7
10
1.3
1.1
7
17
6
65
3-15-70
1
10
16.2-
9-7
40
1.6
1.3
19
13
9
30
3-16-70
1
10
27.0
18. if
32-
1.4
0.7
50
38
14
62
3-16-70
X
10
16.2
9.7
UO
1.3
0.8
39
6
1
83
3-16-70
1
10
19.4
10.8
1.9
Q. 8
58
9
2
78
3-17-70
1
10
15.1
13.0
14
1.0
0.7
30
8
3
62
-------
Table A-4
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Multi-Media Filtration
Synthetic Combined Sewage Sample
Pretreatment by Alum Flocculation and Sedimentation
COD
BOD
Suspended Solids
Batch
Run
Percent
Percent
Percent
Date
Nunber
Number
Flew Rate
Feed1
Effluent
Removal
Feed1
Effluent
Removal
Feed1
Effluent
Removal
gpm/sq.ft.
mg/l
mg/L
mg/L
mg/L
mg/L
mg/L
5-20-70
5
6
5
40.7
55.5
13
2.7
1.7
57
12
5
58
3-21-70
5
6
5
57.5
34.2
9
5-5
2.0
59
15
6
60
5-21-70
5
7
20
59.6
34.2
14
2.5
1.4
44
14
8
43
3-21-70
5
7
10
37.8
56.7
5
5.5
1.5
57
9
4
55
3-22-70
5
7
10
58.9
59.8
—
5.^
1.5
56
14
5
63
3-22-70
6
1
10
1*5.2
57.8
12
7.3
3.5
52
19
3
84
3-22-70
6
2
15
42.5
39.2
8
6.9
3.5
49
14
11
21
3-25-70
6
2
15
58.2
56.0
6
4.4
5.1
30
15
5
67
5-25-70
6
2
15
59.2
41.4
—
6.0
5.0
50
17
4
76
5-25-70
6
2
15
40.5
56.0
11
8.0
5.0
57
10
3
70
5-24-70
6
2
15
40.3
50.1
7.0
^.0
28
3
1
66
Supernatant of alum flocculation and sedimentation.
-------
Table A-5
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Multi-Media Filtration
Anacostia River Water
Pretreatment by Alum Flocculation and Sedimentation
Date
Run
Number
Flow Rate
COD
Percent
Feed1 Effluent Removal
gpm/sq.ft. mg/L mg/L
BOD
Percent
Feed1 Effluent Removal
mi
g/L mg/L
Suspended Sol ids
Percent
Feed1 Effluent Removal
g/L mg/L
m
vO
3-28-TO
3-29-70
20
10
10.0 7.5 25 1.6 l.k
12.5 7.5 to 1.9 1.7
12
11
lit-
13
79
92
3-29-70
20
17.3 9.9
1^3
1.5 0.7
53
19
53
3-29-70
20
13.6 11.1
12
lk
71
xSupernatant of alun flocculation and sedimentation.
-------
Table A-6
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Multi-Media Filtration
Combined Sewage Sample Using
Synthetic Anacostia River Water
COD
BOD
Suspended Solids
Batch
Run
Percent
Percent
Percent
Date
Number
Number
Flow Rate
Feed1
Eff1uent
Remova1
Feed1
Eff1uent
Remova1
Feed1
Effluent
Remova1
gpd/sq.ft.
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
3-31-70
10
1
10
57.4
49.0
14
25.0
19.0
24
26
18
31
3-31-70
10
1
5
61.6
44.4
28
19.4
13.2
32
58
19
67
3-31-70
10
1
5
59.4
38.7
35
15.2
11.1
27
49
17
65
14.-1-70
10
1
5
51.2
42.1
18
19.6
10.1
48
26
5
81
4-1-70
10
1
5
51.8
42.4
18
15.0
6.0
60
38
13
66
4-2-70
11
1
5
37.7
27.7
26
11.0
0
100
35
8
77
4-2-70
11
1
5
33.3
23.3
30
14.0
4.0
72
14
5
64
4-2-70
11
1
5
30.0
22.2
26
20.0
10.0
50
21
5
76
4-3-70
11
1
5
28.3
26.2
34
14.0
7.0
50
7
8
—
4-3-70
11
1
5
30.5
24.0
24
_ _
_ _
7
1
86
Supernatant of alum flocculation and sedimentation.
-------
Table A-7
Kingman Lake
Federal Water Quality Administration
Washington, D.C,
Comparison of Multi-Media and
Fiberglass Filtration
Mult i-Med ia F iberglass1
Flow Rate, gpm/sq.ft. 5 5
Run Time, hours 1 9
Chemical Oxygen Demand (COD)
Concentration in Feed, mg/L 159 197
Concentration in Effluent, mg/L U-8 5$
Percent Removal 70 70
Biochemical Oxygen Demand (BOD)
Concentration in Feed, mg/L 3l«7 .^-8.0
Concentration in Effluent, mg/L 6.0 12.0
Percent Removal 8l 75
Suspended Solids
Concentration in Feed, mg/L 580 536
Concentration in Effluent, mg/L 86 8
Percent Removal 85 98
fiberglass did not return to original condition when backwashed
121
-------
Table A-8
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Activated Carbon Adsorption
Following Alum Pretreatment and
Multi-Media Filtration
Samp 11
COD
Feed1 Eff1uent
mg/L
mi
ig/L
BOD
Feed1 Effluent
mg/L
m'
Suspended
Sol ids
Feed1 Effluent
g/L mg/L mg/L
Total Carbon
Feed1 Effluent
mg/L m
Total Organic
Carbon
Feed1 Eff1uent
g/L mg/L mg/L
Synthetic Mix
35
3.5
1.2
31
22
15.5
5.5
Anacostia River
Water
1.8 1.0
5.^
2.k
Synthetic Mix
3b
12
11.2 3-9
10
IT
13.6
3^
"'"Effluent from multi-media filtration.
-------
Date
Batch
NwAer
5a«ple
Treatment
3-12-70
5
5-15-70
5
3-iwro
5
5-15-T0
It
3-16-70
h
5-21-70
5
3-22-70
5
3-25-70
6
5-2MO
7
3-26-70
7
5-28-70
8
3-29-70
9
5-51-70
10
U-2-70
11
*-3-70
11
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Reservoir Water
Reservoir Water
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Raw Sewage plus
Reservoir Water
Anacostia River
Anacostia River
Raw Sewage plus
Anacostia River
Raw Sewage plus
Anacostia River
Raw Sewage plus
Anacostia River
None
None
None
50 mg/l -
Alum
50 mg/L -
Alua
50 mg/l -
Al urn
50 mgA -
Alu*
50 mg/l -
None
50 mg/l -
Alia*
100 mg/l -
Alum
100 mg/l -
AI on
100 mg/l -
Alum
*Stripping.
Table A-9
Kingman Lake
Federal Water Quality Administration
Washington, B.C.
Phosphorus Removal
Total Phosphate
Supernatant Multi-Media Filter Activated Carbon TotaI
Initial
Nix
After
Treatment
Percent
Removal
Influent
Effluent
Percent
Removal
Influent
Effluent
Percent
Removal
Percent
Removal
mg/l
mg/l
mg/l
mg/l
mg/L
mg/l
23.1
—
~
23.1
1U.5
37
1^.5
6.5
55
72
23.1
20.5
U
20.5
12.5
39
1*6
23.1
20.0
13
20.0
19.0
5
18
0.13
0.13
0.12
8
0.12
2.55
*
*
0.13
0.11
15
0.11
1.U7
*
*
29.0
11.1
62.0
11.1
10.2
8
10.2
0.5
95
98
11.1
10. fc
6
10. k
l.U
87
95
11.1
10.0
10
10.0
3.0
70
90
51.0
12.0
61.0
12.0
9.0
25
9.0
5.6
38
82
12.0
6.0
50
6.0
5.0
17
8U
2.0
2.0
Nil
100
2.0
OA
80.0
O.k
0.05
87
0.05
0.60
*
*
30.0
11.5
62.0
• 11.5
10.0
13
10.0
2.7
62
91
30.0
5.0
90.0
3.0
2.5
17
2.5
1.5
Uo
95
3 A
2.1
38
2.1
1.2
^3
96
-------
Table A-10
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Provisional Algal Assay Study
Algal Growth/ Total
Samp 1e Li ter of Sample PO^
Nutrient Water (Control) 4-50 1.9
Raw Sewage 834 51.0
Synthetic Storm Overflow Mixture 350 20.4
Tri-Media Filter Effluent 450 14.5
Activated Carbon Treatment Effluent 633 12.5
Reservoir Water 100 .2
Nutrient Water 550 1.9
Anacostia River Water 117 .4
Pilot Plant Final Effluent 134 .6
124
-------
No.
1
.2
3
k
5
6
7
8
9
10
11
1
2
3
Table A-t 1
Kingman Lake
Federal Water Quality Administration
Washington, D.C.
Thickened Sludge Dewatering
Spec i f i c
Resi stance
Filter Aid Dose X 10° Comment PSI °C
12!
% dry solids sec /gm
None
F"e€ 1,
FeCl ^
Lime
FeCl
Lime
C-31
Reten 210
C-7
N-12
990-N
A-23
15%
20%
8%
k%
16%
2%
.5%
.5%
.5%
.5%
.5%
5,350
720
598
2,300
845
570
1,110
1,800
1,800
1,650
1,670
359
80.8
61.6
Thickened sludge
Solids Concentration
12.5%
High Pressure -
Heat Treatment
100
250
290
82
79
82
-------
FIGURE A-l
LABORATORY MULTI-MEDIA FILTER COLUMN
126
ANTHRACITE 2.0-2.8 MM
SAND 0.5-1.0 MM
FINE GARNET 0.35-1.00 MM
COARSE GARNET 1.4-4.0 MM
FINE GRAVEL 4.0-8.0 MM
medium GRAVEL 5 _ a inches
16 8
-------
FIGURE A-2
KJ
\l
MULTI-MEDIA FILTRATION-ACTIVATED CARBON ADSORPTION
PILOT PLANT FLOW DIAGRAM
CHLORINE
CONTACT
CHAMBER
-------
FIGURE A-3
LABORATORY FIBERGLASS FILTER COLUMN
ANTHRACITE
2.0-2.8 MM
7.51 LBS/FT3
9.0 0 LBS FT3
12.25 LBS/F T3
37.82 LBS/FT3
128
-------
APPENDIX B
APPLICATION OF TUNNEL STORAGE TO
NORTHEAST BOUNDARY TRUNK SEWER
General Concept
The application of tunnel storage to the Northeast Boundary Trunk Sewer
would provide a means both for reducing the frequency of surcharging and
for intercepting the combined sewage which normally overflows to the
Anacostia River. The proposed tunnel storage concept begins by inter-
cepting flow in excess of the hydraulic capacity of the combined sewer.
The intercepted flow is conveyed to the tunnel by vertical shafts and
stored until stormwater flow subsides, and then it is pumped back into
the sewer for conveyance to either the Blue Plains Treatment Plant or
to the proposed water reclamation facilities at Kingman Lake.
Preliminary study indicates that an attractive location for the proposed
tunnel is under Florida Avenue from 9th Street to Maryland Avenue, as
shown in Figure B-l. This represents approximately 13,000 lineal feet
of tunnel.
Storm flow relief is provided for the sewer system by intercepting the
flow at various locations, not just one, as shown in Figure B-l. The
maximum flow to be intercepted at each of the proposed locations is as
follows:
Magnitude of
Location Intercepted Flow
1. Intersection of Florida Avenue
and Georgia Avenue 900 cfs
2. Intersection of Flow Avenue
and North Capitol Street 1,300 cfs
3. Intersection of Florida Avenue
and 4th Street NE 1,300 cfs
4. Florida Avenue between West
Virginia Avenue and Montello Avenue 1,670 cfs
A preliminary design of a typical intercepting system is shown in Figure
B-2. The design and function of each intercepting system are similar,
but vary as to the specific sizes of components. An initial overflow
pipe is set to intersect the combined sewer in such a manner that the
crown of both the overflow pipe and the combined sewer are at the same
elevation. Combined sewage enters the overflow pipe through a trash
rack, drops through a submerged orifice, and flows a short distance to
the entrance of a vertical shaft. Flow entering the vertical shaft falls
into a plug pool sized such that the energy of the combined sewage
(falling at or near terminal velocity) is sufficiently dissipated. Armor
129
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plating is placed on the bottom of the plunge pool directly beneath the
vertical shaft to prevent damage to the structure when the initial in-
fluent begins to enter the empty plunge pool. A pipe hydraulically sized
to accept the peak influent rate provides for flow from the plunge pool
to the storage tunnel. A smaller second pipe, located at the base of
the plunge pool, functions as a drain from the plunge pool to prevent
the stagnation of the standing combined sewage and resulting odor prob-
lems .
It is also proposed that the tunnel be located entirely within bedrock,
be constructed by the use of both mole and conventional mining techniques,
and have a semi-circular configuration on the top with a rectangular
base. Even if the tunnel is located within bedrock, it is reasonable
to assume that some lining may be required to seal fractures in the
bedrock; however, it is not anticipated that any such lining will be
extensive.
It is proposed that the tunnel be sloped 1.5 feet per 1,000 feet, to
permit it to fill from its lower extremity. As soon as the tunnel
fills to a predetermined level at each vertical shaft, a sensor sends
a signal to a hydraulically actuated sluice gate in the overlying over-
flow pipe from the combined sewer. Upon receiving this signal, the
sluice gate closes. This process continues until all four gates are
closed, which is when the tunnel is completely full. Stored flow is
pumped back to the combined sewer when the storm flow in the combined
sewer subsides. An estimate of the capital cost involved in this
project (based on the ENR Index «= 1320) is presented at the end of
this appendix.
Geological Investigation Program
Prior to any definite decisions in regard to tunneling, it is imperative
that geologic studies be conducted to evaluate subsurface conditions,
not only in the proposed tunnel area, but also at the proposed locations
of subordinate structures. This evaluation would consist of study of
existing data, development and implementation of a subsurface investi-
gation program, laboratory and field testing, and analysis and inter-
pretation of the results.
Data Collection
All available pertinent data should be collected and evaluated prior to
the subsurface exploration program. Much data can be collected from
governmental agencies such as the U. S. Geological Survey, D.C. Highway
Department, and the Metropolitan Area Transit Authority. Other sources
of data would be from tunneling contractors who are presently working
in the area or who have constructed tunnels in the District of Columbia.
Subsurface Investigation Program
Subsequent to the collection and review of all pertinent available data,
a detailed subsurface investigation program should be developed. This
program should include:
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1. Seismic Survey - A series of seismic surveys should be
made in the vicinity of the proposed tunnel in order to
establish preliminary subsurface profiles depicting the
soil and bedrock conditions and the presence of fault
zones.
2. Test Boring Program - Numerous test borings should be
made along the location of the proposed tunnel. The
program should be designed to investigate both soil
and bedrock conditions. The depth of the test borings
should extend an adequate distance below the invert
elevation of the proposed tunnel, so that an accurate
picture of bedrock conditions can be obtained.
3. Geophysical Borehole Logging - Selected boreholes should
be logged by geophysical methods in order to establish
known reference points for the seismic surveys and to
aid in the correlation of the detailed information ob-
tained during the test boring program. In addition, a
great amount of data concerning resistivity, lithology,
porosity, permeability, and rock density can be obtained
through use of geophysical logging techniques. These
logging techniques would include the following: induc-
tion logging, formation density logging, sonic logging,
gamma-ray neutron logging, formation tester logging, and
temperature logging.
A. Borehole Photography - In order to obtain additional in-
formation on bedrock strength and structural character-
istics , the use of borehole photography is extremely
helpful. Through the use of borehole photography, such
important data as frequency of joints, presence of faults
and shear zones, and attitude (strike and dip) of joints,
cleavage, and faults can be obtained.
5. Pressure Meter Testing - Pressure meter testing should
be performed in selected boreholes. By means of a
pressure meter device, an estimate can be made of the
in situ deformation characteristics of the bedrock at
the depths of the proposed tunnel. From the deformation
measurements the apparent in situ modules of elasticity
of the rock can be computed. Additionally, through this
type of testing, an indication can be obtained of the
importance of jointing or other structural weaknesses.
6. Water Pressure Testing - Water pressure tests should be
performed at selected boreholes for the purpose of de-
termining the variations in permeability coefficients of
the bedrock in order to ascertain the average rate of in-
flow to the tunnel. Another purpose of this type of test-
ing is to determine the existence of highly pervious
jointed or sheared zones, where a blow-in of rock mater-
ial might occur.
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7. Water Well Drilling and Testing - A program of well drill-
ing and testing should be implemented. A number of wells
should be drilled for testing and observation purposes.
By means of a series of pumping and recharge tests, data
can be obtained to determine the hydrologic parameters
of the pertinent aquifers and to ascertain ground-water
inflow and recharge conditions. The underlying purpose
for this step in the investigative procedure is to pro-
vide information on potential aquifer pollution problems.
It is imperative that the hydraulic grade line of the
proposed tunnel below the piezometric level of the
ground water. This will cause the tunnel to be subjected
to external pressure, which would cause inward flow of
ground water to the tunnel. As long as the tunnel is
subject to external pressure, the hazard of ground
water contamination does not exist. Any lowering of
the piezometric level to below the hydraulic grade line
of the tunnel would cause an outward flow from the tun-
nel thus creating the hazard of ground-water contamina-
tion. Some of the wells can be placed in locations that
will permit their use as monitor wells after construction
of the tunnel, so that a continuing check can be made
to see that the system is operating properly.
Laboratory Testing
Soil Testing
Soil tests should be performed on split-spoon and undisturbed soil samples
taken during the test boring program. The type of tests to be performed
should include: moisture content, Atterberg limits, gradation analysis,
unconfined compression, triaxial shear, direct shear, and consolidation.
Through the use of these tests, the soils can be identified, and their
strength characteristics can be evaluated. These data are particularly
important in regard to the vertical access shafts to the tunnel and other
structures related to the proposed facility.
Rock Testing
Laboratory testing of rock cores taken during the drilling program is a
necessary part of the investigation. These cores should be examined
carefully to determine rock quality, joint frequency, zones of weakness,
other properties that could affect compression. Various hardness tests
should be performed to determine the structural strength and drillability
characteristics of the rock. Such tests will be of significant value
in determining the optimum design and construction methods.
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Table B-l
Estimated Cost Summary
Tunnel Construction for Surcharge Relief
and Storage
Tunnel at $818.00/LF1 $10,585,000
Pumping Station 2,383,000
Shaft Construction
Excavation 835,000
Concrete Work 2,855,000
Piping and Manholes 164,000
Boring and Jacking 187,000
Sluice Gates and Armor Plating 156,000
Sub-Total $17,165,000
Construction and Escalation Contingency 2,574,000
TOTAL $19,739,000
^Updated from ENR 1142 and increased for larger diameter (factor 0.6).
133
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FIGURE B-1
GENERAL TUNNEL LOCATION
4s'
sY
MICHIGAN
AVE.
MC MILLIAN
RESERVOIR
V
ilL*H
,
-------
FIGURE B-2
GENERAL SCHEME VERTICAL SHAFT
135
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APPENDIX C
PRELIMINARY SOIL AND FOUNDATION INVESTIGATION
The report of this investigation by Joseph S. Ward and Associates is
annexed to this report as a separate volume. Significant portions of
the above report have been excerpted and placed within the body of
this reptort as required.
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APPENDIX D
INVESTIGATION OF RAINFALL-RUNOFF RELATIONSHIPS
Methodology - Volume of Overflow
The volume of the surface runoff of rainfall from a particular area is
determined by subtracting from the total amount of precipitation the
losses due to interception by vegetation, infiltration into permeable
soils, retention in surface depressions, and evaporation. Of these,
infiltration and retention in depressions are the only losses of
significance in urban drainage. Numerous runoff coefficients ac-
counting for the combined effect of these losses have been widely
reported; however, the use of these coefficients calls for extensive
judgment because the coefficient will vary throughout the duration
of the storm. It is more precise to account for these losses sep-
arately and to examine their variability through time.
The methodology employed to account for these losses involves the
development of hyetographs. Intensity-duration-frequency relation-
ships for the Washington, D.C. area have been formulated and plotted
in a previous study using rainfall data collected during a 60-year
period from 1894-1954. These relationships are defined in the follow-
ing equation:
J-avg
where:
(td + b)
(1)
td ¦ duration of storm corresponding to a period of
maximum rainfall, minutes
iaVg " average intensity during particular duration,
in/hr
a,b,c - constants for particular return frequencies
Using differential and integral calculus, the equation of the hyetograph
is derived from equation (1) to be as follows:
(2a)
(2b)
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where:
= time before the peak intensity, minutes
ta = time after the peak intensity, minutes
i^ = instantaneous intensity before the peak
intensity, in/hr
i = instantaneous intensity after the peak
intensity, in/hr
r = portion of any duration of maximum
rainfall occurring before the peak
intensity NOTE: t^ = rt^, ta = (l-r)td
a,b,c = constants from equation (1)
Essential to this study is an analysis of the consequences of the three-
month rainfall; however, the amounts of rainfall occurring with a fre-
quency interval of less than two years have not been determined in past
studies for the Washington, D.C. area. To determine the three-month
rainfall, an array was developed using par.tial duration series data on
excessive precipitation collected by the U.S. Weather Bureau for the
ten-year period 1960-1969. In this period, there were seventy-six storm
events with precipitation values in excess of the minimum values of inter-
est as defined by the U.S. Weather Bureau. For each storm event, the U.S.
Weather Bureau listed the maximum precipitation occurring for specific
durations (12 durations were listed, ranging from 5 to 180 minutes). The
seventy-six storms were ranked for each of the twelve durations. Using
the Weilbull formula^, the three-month storm is defined as between the
40th and the 41st ranking, and precipitation values were selected
accordingly from the array. An average intensity-duration-frequency
equation was derived for the selected values, and for the a, b, and c
constants of this equation of the hyetograph.
A study (17) of the storms occurring in the Chicago area showed that r in
equation (2) has a weighted average value of 3/8. A detailed examination
of twelve consecutive months of rainfall as recorded at the Washington
National Airport Station indicates that a value of 3/8 is reasonable for
the Washington, D.C. area. Hyetographs for the relevant storm frequencies
were developed on the basis of this value and of the values for a, b, and
c. As an example, Figure 1 in the main report is the hyetograph for the
5-year frequency storm.
5 . _ N + 1
where: Tr =
m
Tr = return frequency
N = number of periods of record
m = position number of event ranked in order of
descending magnitude
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Research (18) indicates that the capacity which a soil exhibits for in-
filtration varies little with surface slope and depends primarily on soil
porosity, ground cover, and antecedent rainfall. Infiltration capacity
curves have been developed for various soil and surface conditions, and
two of the mostly commonly used curves are shown in Figure 2 of the main
report.
The capacity for infiltration is relatively high at the beginning of
precipitation and decreases rapidly to a rather definite minimum value.
During periods when the rate of precipitation is less than the infil-
tration capacity, all precipitation is infiltrated; when precipitation
is greater than the infiltration capacity, excess runoff is produced
in an amount equal to the difference between the precipitation rate and
infiltration capacity. Consequently, an analysis of runoff requires the
simultaneous examination of precipitation rates and infiltration capacit-
ies as they vary through the duration of the storm.
Figure 3 (of the main report) is a graph of the accumulated mass of rain-
fall and the accumulated mass of infiltration for residential type per-
vious surfaces versus time from beginning of significant rainfall. For
storms in which the precipitation rate is initially less than the infil-
tration capacity, it is reasonable to assume the same amount of infil-
tration will occur as if the infiltration capacity was exceeded, but
at some later time in the course of the storm. Therefore, the time of
the start of excess is found by shifting the accumulated mass of in-
filtration curve along the time axis until it is tangent to the accumulated
mass of rainfall curve. The actual mass infiltrated follows the trend
of the accumulated mass of rainfall from zero time to the point of
tangency, and from there it follows the offset curve of accumulated mass
of infiltration up to the point when infiltration again equals the rate of
precipitation. To define the latter point, the infiltration capacity
curve is plotted with the hyetograph but at a time-offset equal to the
offset of the accumulated mass of infiltration curve. The point at
which infiltration again equals precipitation is defined as the second
intersection of their curves. This procedure is illustrated in Figure
4 of the main report.
After the precipitation rate again drops below the infiltration capacity,
the deficit is satisfied in part by infiltration from runoff traveling
overland. It is conservative, but reasonable, to assume that for an
urban area of moderate grade and intense development such as the North-
east Boundary Trunk Sewer basin, the time of overland travel on a pervious
surface is so short that this type of infiltration is insignificant. On
this basis, the rainfall is excess of infiltration is defined as the
difference between the accumulated mass of rainfall curve and the actual
accumulated mass infiltration curve at the point when the rate of
precipitation equals for the second time the infiltration capacity. The
rainfall in excess of infiltration is shown in Figure 3 of the main re-
port.
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In this study, the rainfall in excess of infiltration was determined for
pervious surfaces characteristic of residential and commercial-industrial
areas. It is assumed in this study that infiltration is negligible for
impervious surfaces and that runoff from an impervious onto a pervious
surface is insignificant, or at least the effect of such is negligible.
A past study by the D.C. Department of Sanitary Engineering provides a
sound basis for determining the area of pervious and impervious surfaces
in the Northeast Boundary Trunk Sewer basin. In the study, the pervious
and impervious areas of typical blocks of the city w^re reported as
follows:
The overall surface characteristics of the Northeast Boundary Trunk Sewer
basin were determined by assuming that zoning categories R-l and R-2
correspond to the single house residential block type; R-3, R-4, and
R-5 correspond to row house residential block type; C-l, C-2, C-M, and
M correspond to neighborhood and commerical block type; park area is
totally pervious; and C-3 and C-4 are totally impervious. On this basis,
the surface of the drainage area is 57.8 percent impervious, 37.6 percent
residential-type pervious, and 4.6 percent commercial-type pervious.
It should be noted that any hyetograph is asymptotic to the time axis.
However, in this study the hyetograph was not extended beyond the point
at which rainfall intensity is less than 0.2 inches/hour. For pervious
surfaces, the minimum infiltration is greater than 0.2 inches/hour and
there is no need to examine rainfall past this point. Nevertheless,
prior to the peak of a storm the mass of rainfall preceding an intensity
of 0.2 inches/hour may be significant. To account for this, it was
assumed that this mass is equal to the volume of runoff discharging to
the East Side Interceptor prior to the closure of the sluice gate. For
impervious surfaces, the total amount of precipitation for each rainfall
frequency examined was the 24-hour duration value read from the updated
Washington, D.C. intensity-duration-frequency curves published by the
Special Studies Branch of the Office of Hydrology of the U.S. Weather
Bureau. These curves represent National Airport records for 1951-1969
combined with City Office records for 1896-1897 and for 1899-1950.
A significant volume of the rainfall in excess of infiltration is re-
tained in surface depressions, and it either evaporates or infiltrates
after the storm subsides. Observations made during periods of heavy
rainfall for the flat topography of Chicago suggest that the^ overall
average depth of depression storage is 0.25 inches on pervious areas
and 0.06 inches on paved areas (19). In a widely accepted design manual
(20), various investigators have observed that in urban areas of moderate
grade the overall average depth of surface depressions is about 0.05
Block Type
Pervious
Impervious
Residential, single house
Residential, row house
Commercial, neighborhood
54.1 percent
35.8 percent
25.8 percent
45.9 percent
64.2 percent
74.2 percent
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inches for impervious surfaces and about 0.10 inches for pervious surfaces.
The values reported in the design manual were assumed to apply to the
Washington, D.C. area and were subtracted from the mass of rainfall in
excess of infiltration.
The application to a large drainage area of rainfall data collected at
one point outside the area requires careful interpretation of two
phenomena:
a. The difference in prevailing physical conditions
at two separate, but proximate, locations may
result in different extreme rainfall data.
b. Average depth of rainfall over a large area is
less than maximum point rainfall.
As for the former, the atmospheric forces of extreme storms are greater
than the local effects of terrain and thermal patterns in the Washington
area, and there should be no difference in extreme rainfall data (i.e.
intensity versus frequency) at two separate sites in the area. To
account for the latter, a correction factor of 98 percent was extrapolated
from the area-depth relationship used by the D.C. Department of Sanitary
Engineering. The volume of runoff from the Northeast Boundary Trunk
Sewer drainage basin is determined by multiplying the mass of rainfall
(less abstractions) by the appropriate surface area, summing, and
reducing by two percent to account for the depth-area relationship.
In addition to the Northeast Boundary Trunk Sewer, there are ten
separate storm sewers which discharge directly into Kingman Lake. Any
development of the lake for swimming will require their diversion, and
it is only reasonable that they be diverted to the storage facility that
would be constructed to contain overflow from the Northeast Boundary
Trunk Sewer. Although the drainage area served by these sewers is out-
side of the Northeast Boundary Trunk Sewer drainage basin, the runoff
conveyed by the sewers must be included in any design considerations.
The drainage area served by the three sewers is 350 acres, and its sur-
face is characterized as being 20 percent residential pervious and 80
percent impervious. The same methodology was used to determine the
runoff from this area.
A significant volume of dry-weather sewage flow (DWF) is also included in
the overflow from the Northeast Boundary Trunk Sewer. Examination of a
1957 study (21) indicated that storms with a return frequency interval of
1 year or more will each result in overflow with a duration of at least
10 hours, while the more frequent storms will have an overflow duration of
approximately 6 hours each. These values were used along with a DWF of
27.4 mgd to determine the volume of sewage included in the combined over-
flow.
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Results-Volume of Overflow
In review, there are three sources of overflow:
1. Storm water runoff from the Northeast Boundary Trunk Sewer,
2. Storm water runoff from the separate storm sewers adjacent
to Kingman Lake, and
3. The dry-weather sewage flow.
The storm water runoff originates from impervious surfaces, pervious
residential surfaces, and pervious industrial-commercial surfaces. The
overflow volumes for a range of rainfall frequencies were determined using
the discussed methodology. These results are shown in Figure 5 and Table 3
of the main report.
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APPENDIX E
LITERATURE EVALUATION OF ALTERNATIVE
WASTEWATER TREATMENT PROCESSES
Microstraining of Combined Sewer Overflows
The application of the Microstrainer to the removal of suspended solids
has been field tested in Philadelphia by the Crane Company. Under a re-
search grant froii) the FWPCA (Contract No. 14-12-136) (22), a pilot test
unit was installed at a sewer outfall serving an 11-acre area on the
western side of the City. The system was operated intermittently over a
9-month period in 1969.
The Microstrainer test unit consisted of a horizontal rotating drum, 5
feet in diameter and 3 feet in length, covered by a stainless steel woven-
wire fabric. Raw water entered one end of the partially submerged drum
to flow radially outward through the fabric. Suspended solids were re-
tained on the inside of the fabric, which had openings of 23 microns on a
side. As the drum rotated, dirty fabric emerged from the water and back-
wash jets flushed the retained solids from the fabric into an intercepting
hopper suspended inside the drum. In a full-scale installation, the
solids would be conveyed to a sewage treatment p^ant for disposal or
handled in an on-site disposal system.
Suspended solids removal on the order of 65-95 percent (volatile suspended
solids removal of 50-90 percent) appears feasible for this system. The
paucity of data prevents a more definitive conclusion as to the solids
removal capability of the Microstrainer under the operating conditions
of this stufly. Data on the removal of BOD and fecal coliform bacteria
were non-conclusive since increases in BOD and fecal coliform were ob-
served as often as not.
The system was operated during a total of 26 storm events. During 17 of
those events, the filtration rate was less than 10 gallons per minute per
square foot of submerged screen surface area; six runs were made at rates
of between 10 and 15 gpm/sq.ft. and three runs were made where the rate
exceeded 15 gpm/sq.ft. (once each at 15.6, 27.2 and 46.0 gpm/sq.ft.).
During those 9 runs at a rate of 10 or more gpm/sq.ft., the average sus-
pended and volatile suspended solids removals were 76 and 69 percent,
respectively, while the average effluent concentrations were 28 and 9
mg/L, respectively. Influent concentrations of suspended and volatile
suspended solids were 195 mg/L and 34 mg/L, respectively. Influent
BOD5 averaged 245 mg/L.
Cost data has been developed by the Crane Company for a 10-mgd treatment
plant experiencing forty overflow events per year and were based upon a
flow rate of 45 gpm/sq.ft. of submerged filter. The capital cost of such
a plant including equipment procurement, installation and building, but
excluding cost of land and engineering fees was reported to be $79,500.
Operating cost including maintenance, supplies, and replacement parts at
1 percent of capital cost has been set at $800 per year.
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However, the use of a filtration rate of 45 gpm/sq.ft. as the basis of
the cost analysis does not appear justified on the basis of the manufac-
turer's data since sixty-five percent of the runs were made at less than
10 gpm/sq.ft. and only one run was made at a rate greater than 30 gpm/sq.ft.
Therefore, a flow rate of 10 gpm/sq.ft. would be a more reasonable design
rate and the design capacity for a 50-mgd plant would be 22.5 times the
capacity assumed by the Crane Company for their cost analysis. A reasonable
cost scale-up would be approximately 60 percent of the capacity scale-up
factor, or about 13.5 times this estimate.
On this basis, the capital cost estimate would be approximately $1,070,000,
while the annual operating cost would be at a minimum of 1 percent of
capital cost, or $10,700 per year. Estimates have also been made on the
basis of $60,000 per Microstrainer unit and a requirement of seventeen
units, each having a submerged surface area of 210 square feet. Capital
cost, in this case, would then be $1,020,000 and the estimated operating
cost would be $10,200 per year.
The firm of Cornell, Howland, Hayes and Merryfield (23), under contract
with FWPCA, evaluated the applicability of Rotary Screen manufactured by
SWECO, Inc., for primary treatment of combined sewer overflow. The
rotary screening device is very similar in principle to the microstrainer,
and utilizes a stainless steel wire screen. Otherwise, the equipment
involved in this process is very different.
In this unit, raw water is fed into the top of the apparatus to discharge
against a stationary distribution dome which changes the direction of
flow from vertical to horizontal (radial). The feed water then strikes
a rotating (60 rpm) 165-mesh collar screen at a velocity of approximately
11 feet per second. Most of the feed water (70-90 percent) penetrates
the screen and is discharged as screened effluent to be disinfected out-
side the screening unit. The screens are cleaned by a hot solution of
concentrated caustic (sodium hydroxide) being sprayed by high pressure
nozzles for 30 seconds after a 4-1/2 minute screening cycle. The re-
tained solids drop into a solids discharge pipe and are taken out of
the system.
Tests were performed by the manufacturer under the FWPCA grant on both
combined sewer overflow and undiluted raw sewage. The investigators
describe the operating performance of their unit as comparable to primary
clarification. Suspended solids removal of 34 percent was reported from
an influent concentration of 122 mg/L leaving an effluent concentration
of 87 mg/L. COD was reduced by 27 percent from an initial concentration
of 300 mg/L in the feed water. Settleable solids of 5.7 mg/L were 98
percent removed. The test run which produced these results was termi-
nated after 6 hours due to a screen failure.
The operating performance of the screen was concluded to be the limiting
component of the entire unit. Ninety percent of the screen failures
experienced in the study were due to hydraulic overloading; 10 percent
were attributed to punctures and caused by objects contained in the
feed water.
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A cost analysis was developed for an automated 25-mgd treatment plant
housed In a structure with lateral dimensions of 30 feet by 75 feet.
Based on a throughput capacity of 130 gpm/sq.ft., the proposed plant
would consist of ten 2.5-mgd screening units. The capital cost was
estimated to be $560,000 including the design engineering fee and exclud-
ing land costs and costs for disinfection. The operation and maintenance
cost, based on a screen life of 500 hours, was estimated to be $18,500/
year. However, the manufacturer's operating data on the rotary screening
device, does not support a life expectancy on the screen of more than
6-10 hours since the screen required replacement of their operation after
a 6-hour run. Consequently, a screen-life of 500 hours seem highly
optimistic and not a suitable basis for a cost analysis.
If a 6-10 hour life expectancy is assumed, the annual operating and
maintenance cost would be more in the range of $200,000/year for the
25-mgd plant. By scaling the cost estimates up to a 50-mgd capacity
plant, the capital cost would be approximately $1,000,000 and the annual
operation/maintenance cost would exceed $400,000 per year.
In conclusion, the rotary screening device does not appear to be applicable
at this time to this project due to two factors: 1) effluent quality
would not meet the requirements of .either a pretreatment or a final
treatment facility; 2) the high capital and operating and maintenance
cost would be prohibitive for the degree of removal obtained in the
manufacturer's studies.
U-Tube Aeration
A U-Tube aerator consists of two basic components: a conduit to provide
a vertical U-shaped flow path, and a device for entraining air or oxygen
into the streamflow in the down-leg of the conduit. The conduit may be
a circular or rectangular (cross section) tube in the shape of a U; or
a pair of concentric pipes with flow downward through one and upward
through the other; or a trench (e.g. immediately downstream from the
crest of a weir or dam) with flow downward and under a dividing baffle
wall to flow upward on the other side. The entrainment device is one
of two types: aspirator, or compressor and diffuser. In either case,
the air bubbles are carried along the down-leg of the tube because the
water velocity exceeds their bouyant rising velocity.
The unique features of the U-tube process are fundamentally two-fold:
both contact time and the dissolved oxygen deficit are increased and
efficiently utilized. Increased pressures, controlled surface area, and
turbulence all help to increase oxygen transfer efficiency both in terms
of oxygen transferred per unit mass of water treated and oxygen transferred
per unit of energy. In addition to being capable of operation under a
positive, zero or negative head (by proper positioning of entrainment
device), the U-tube system requires virtually no moving parts and requires
no operating labor and little maintenance. The advantage of high transfer
efficiency-low energy input requirement also serves to limit the process
to aeration; i.e. the device is not an effective mixer.
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The U-tube aeration process has a limited potential application in each
of the three major retaining basins of the Kingman Lake Project. In the
storage basin, aerobic conditions must be maintained. The dissolved oxy-
gen requirements of the raw wastewater are such that the U-tube process
would not be efficiently applied. Speece (24) noted that U-tube aeration
would be most applicable to situations involving relatively low DO defl
cits, i.e. those situations in which conventional aeration systems are
most poorly suited. The boating and fishing lake, with its relatively
high DO requirements for fish life, appears to be suitable by this cri-
terion. Mitchell and Lev have estimated the cost of post-aeration of
treated (secondary) effluent for 10- and 100-mgd plants. The following
cost data are interpolations from the data of Mitchell and Lev.
Year-round U-tube aeration of 5 mgd would cost approximately $2,600 per
year and would require an initial capital outlay of $25,000. These data
are based on the assumption of no available head, and therefore, include
cost of pumps and power. In comparison, diffused aeration or mechanical
aeration (of equivalent scale) would involve capital costs of $31,000 or
$36,000, respectively. In the same order, annual operating costs would
be $4,200 and $7,700.
Ozonation as a Unit Process for Treatment of Combined Sewer Overflows
Ozone has been proven capable of removing chemical oxygen demand (COD) and
total organic carbon (TOC) from wastewater treatment plant effluents. Used
as a disinfectant, ozone is both bactericidal and viricidal. It also has
the ability to neutralize objectionable odors and to bleach colors from
water. An advantage of ozone over chlorine is its ability to reduce
chlorine demand and to circumvent the formation of objectionable tastes
and odors (such as are produced by nitrogen trichloride during break-
point chlorination in the presence of undecomposed urea). This feature
may be of particular significance when the treated water is to be
recycled.
There are three potential applications for ozonation in the Kingman Lake
Project: 1) removal of dissolved organic materials; 2) disinfection; and
3) odor control.
The use of ozone as a tertiary treatment process has been studied by Air
Reduction Company, Inc. (Airco) under a contract (No. 14-12-114) with the
Federal Water Quality Administration (FWQA) (25). Given the task of de-
veloping an efficient contacting process, Airco found multi-stage, con-
current contacting helpful to the achievement of high ozone-utilization
efficiency, which is the key to the economic feasibility of this process.
Airco contends that the ozonation process can be automated for low-
maintenance service.
As a tertiary treatment process, ozone was found in the Airco study to be
competitive with activated carbon for waters containing less than about
35 mg/L COD. Such an effluent is anticipated from multi-media filtration
following coagulation and sedimentation of combined sewer overflows. The
148
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Airco study achieved COD reduction from 35 mg/L to less than 15 mg/L, and
BOD5 removals from 36 mg/L to less than 5 mg/L. This performance was
accompanied by almost complete removal of color, odor, turbidity, bac-
teria (total removal), and surface active detergents. This degree of
treatment required a total contact time of 60 minutes at an ozone dosage
of 10 to 20 mg/L.
For disinfection purposes, ozone has both advantages and disadvantages in
comparison with chlorine. Ozone is known to be more viricidal than
chlorine. However, dissolved ozone decomposes rapidly in water, having
a half-life of only 20 minutes. An ozone residual is, therefore, not
available to ensure continued or residual protection from expected re-
contamination of bathing water. Any application on the swimming lake
would, therefore, require additional or supplementary application of
chlorine or iodine for the residual effect. Disinfection of fishing
and boating water is a different application in that a residual effect
(harmful to aquatic life) is undesirable. Thus, chlorine residual
would necessitate removal, whereas the lack of ozone residual would
be an advantage.
Odor control at the storage basin may be achieved by injecting ozone
into the air over the enclosed basin at various vent points. Suffi-
cient excess ozone would be available for this application from the
disinfection unit. Ozonation generally involves high capital and op-
erating costs and low labor and maintenance costs. The two major ex-
pense items are plant amortization and power costs.
Tertiary treatment for COD removal by ozonation would require a capital
expenditure of $3,400,000 and an annual operating cost of $386,000 per
year. Disinfection by ozone using air feed would cost $530,000 capital
and $135,000 yearly for operation. Provision of a (chlorine) residual
would add to these costs for initial disinfection. Odor control, in
the absence of ozonation for COD removal, would cost on the order of
$90,000 for an initial capital outlay, and yearly cost of operation would
be approximately $20,000.
149
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BIBLIOGRAPHIC:
ROY F. WESTON, Conceptual Engineering Report, Kingman
Lake Project, FWQA Program No. 11023 FIX, October, 1970.
ABSTRACT:
This conceptual engineering study concerns the reclamation of
combined sewer overflows and utilization of the reclaimed
waters in a major water-oriented recreational facility for the
District of Columbia. The investigation encompasses a compre-
hensive solution of environmental problems by proposing multi-
use objectives and facilities.
Principal objectives of the project included: 1) evaluation of
rainfall runoff relationships for sizing of storage and treatment
plant capacities; 2) confirmation of treatment feasibility using
filtration and an activated carbon process; and 3) development
of sufficient data for preliminary design purposes.
ACCESSION NO.
KEYWORDS:
Activated Carbon
Adsorption
Combined Sewers
District of Columbia
Overflows
Pollution Abatement
Precipitation
Recreation Facilities
Water Storage
Water Reclamation
BIBLIOGRAPHIC:
ROY F. WESTON, Conceptual Engineering Report, Kingman
Lake Project, FWQA Program No. 11023 FIX, October, 1970.
ABSTRACT:
This conceptual engineering study concerns the reclamation of
combined sewer overflows and utilization of the reclaimed
waters in a major water-oriented recreational facility for the
District of Columbia. The investigation encompasses a compre-
hensive solution of environmental problems by proposing multi-
use objectives and facilities.
Principal objectives of the project included: 1) evaluation of
rainfall runoff relationships for sizing of storage and treatment
plant capacities; 2) confirmation of treatment feasibility using
filtration and an activated carbon process; and 3) development
of sufficient data for preliminary design purposes.
ACCESSION NO.
KEY WORDS:
Activated Carbon
Adsorption
Combined Sewers
District of Columbia
Overflows
Pollution Abatement
Precipitation
Recreation Facilities
Water Storage
Water Reclamation
BIBLIOGRAPHIC:
ROY F. WESTON, Conceptual Engineering Report, Kingman
Lake Project, FWQA Program No. 11023 FIX, October, 1970.
ABSTRACT:
This conceptual engineering study concerns the reclamation of
combined sewer overflows and utilization of the reclaimed
waters in a major water-oriented recreational facility for the
District of Columbia. The investigation encompasses a compre-
hensive solution of environmental problems by proposing multi-
use objectives and facilities.
Principal objectives of the project included: 1) evaluation of
rainfall runoff relationships for sizing of storage arid treatment
plant capacities; 2) confirmation of treatment feasibility using
filtration and an activated carbon process; and 3) development
of sufficient data for preliminary design purposes.
ACCESSION NO.
KEYWORDS:
Activated Carbon
Adsorption
Combined Sewers
District of Columbia
Overflows
Pollution Abatement
Precipitation
Recreation Facilities
Water Storage
Water Reclamation
-------
Laboratory studies not only demonstrated process feasibility,
but showed the need for including flocculation and sedimenta-
tion for removal of minute particles, together with chlorine and
iodine addition for maximum disinfection. The recommended
storage/treatment plan provides for a 175 million gallon storage
basin, a 50 million-gallon-per-day reclamation facility and two
46-acre swimming and boating lakes.
Cost effectiveness (Cost/Benefit Ratio) of the project, as envi-
sioned, has been indicated to be 1.6 at an estimated total project
cost of $45,200,000, and an estimated annual operating cost of
$1,777,000. Implementation of the proposed plan would not
only provide a least-cost alternative over single-purpose projects
to attain identical objectives, but would also reduce the annual
pollution now discharged by the Northeast Boundary Trunk
Sewer by approximately 99 percent.
This report was submitted in fulfillment of Program No. 11023
FIX under Contract No. 14-12-829 between the Federal Water
Quality Adminstration and Roy F. Weston, Inc.
Laboratory studies not only demonstrated process feasibility,
but showed the need for including flocculation and sedimenta-
tion for removal of minute particles, together with chlorine and
iodine addition for maximum disinfection. The recommended
storage/treatment plan provides for a 175 million gallon storage
basin, a 50 million-gallon-per-day reclamation facility and two
46-acre swimming and boating lakes.
Cost effectiveness (Cost/Benefit Ratio) of the project, as envi-
sioned, has been indicated to be 1.6 at an estimated total project
cost of $45,200,000, and an estimated annual operating cost of
$1,777,000. Implementation of the proposed plan would not
only provide a least-cost alternative over single-purpose projects
to attain identical objectives, but would also reduce the annual
pollution now discharged by the Northeast Boundary Trunk
Sewer by approximately 99 percent.
This report was submitted in fulfillment of Program No. 11023
FIX under Contract No. 14-12-829 between the Federal Water
Quality Adminstration and Roy F. Weston, Inc.
Laboratory studies not only demonstrated process feasibility,
but showed the need for including flocculation and sedimenta-
tion for removal of minute particles, together with chlorine and
iodine addition for maximum disinfection. The recommended
storage/treatment plan provides for a 175 million gallon storage
basin, a 50 million-gallon-per-day reclamation facility and two
46-acre swimming and boating lakes.
Cost effectiveness (Cost/Benefit Ratio) of the project, as envi-
sioned, has been indicated to be 1.6 at an estimated total project
cost of $45,200,000, and an estimated annual operating cost of
$1,777,000. Implementation of the proposed plan would not
only provide a least-cost alternative over single-purpose projects
to attain identical objectives, but would also reduce the annual
pollution now discharged by the Northeast Boundary Trunk
Sewer by approximately 99 percent.
This report was submitted in fulfillment of Program No. 11023
FIX under Contract No. 14-12-829 between the Federal Water
Quality Adminstration and Roy F. Weston, Inc.
-------
¦j | Accession Number
2
Subject
Field & Group
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
^ ^Organization
ROY F. WESTON
, Inc., West Chester,
Pennsylvania
6 Titte
~~ CONCEPTUAL ENGINEERING REPORTS KINGMAN LAKE PROJECT,
10
—Neijna, Michael S.
Woldman, Michael L.
Buckingham, Phillip L.
Coleman, Ronald E.
Simons, John L.
n
Oc
¦Date
tober, 1970
J 2 Pages
149 p.
Contract Number
FWQA 14-12-829
16
fwq
Project Number
A Program No. 11023
FTX
21
Note
22 Citation
22j Descriptors (Starred First)
*Filtration, *Flow Measurement, *Rainfall-Runoff Relationships, *Recreational Facilities,
Underground Storage, Rainfall Intensity, Depth-Area-Duration Analysis, Storm Runoff,
Overflow, Geology, Organic Loading, Pollutants, Standards, Boating, Fishing, Swimming,
Wastewater Treatment, Activated Carbon, Disinfection, Storage Capacity, Sewers, Tunnel
Design, Technical Feasibility, Annual Costs, Capital Costs, Cost-Benefit Analysis
25
Identifiers (Starred First)
*Combined Sewers
27
Abstract conceptuai engineering study concerns the reclamation of combined sewer over-
flows and utilization of the reclaimed waters in a major water-oriented recreational fa-
cility for the District of Columbia. The investigation encompasses a comprehensive solu-
tion of environmental problems by proposing multi-use objectives and facilities. Princi-
pal objectives of the project included: 1) evaluation of rainfall runoff relationships
for sizing of storage and treatment plant capacities; 2) confirmation of treatment feasi-
bility using filtration and an activated carbon process; and 3) development of sufficient
data for preliminary design purposes. Laboratory studies not only demonstrated process
feasibility, but showed the need for including flocculation and sedimentation for removal
of minute particles, together with chlorine and iodine addition for maximum disinfection.
The recommended storage/treatment plan provides for a 175 million gallon storage basin, a
50 million-gallon-per-day reclamation facility and two 46-acre swimming and boating lakes.
Cost effectiveness (Cost/Benefit Ratio) of the project* as envisioned, has been indicated
to be 1.6 at an estimated total project cost of $45,200,000, and an estimated annual
operating cost of $1,777,000. Implementation of the proposed plan would not only provide
a least-cost alternative over single-purpose projects to attain identical objectives,
but would also reduce the annual pollution now discharged by the Northeast Boundary
Trunk Sewer by approximately 99 percent.
Abstractor
Institution
ROY F. WESTON, Inc.
WR; 1 02 (REV. OCT. 1068)
WRSIC
SEND TOj WATER R ESOURC ES SC I ENTI FIC INFORMATION CENTER
U #. DEPARTMENT OF THE INTERIOR
WASHINGTON. D.C. 30240
~oPO 620—466
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Continued from inside front cover...
11022
—
08/67
11023
—
09/67
11020
—
12/67
11023
—
05/68
11031
- . -
08/68
11030
DNS
01/69
11020
DIH
06/69
11020
DES
06/69
11020
—
06/69
11020
EXV
07/69
11020
DIG
08/69
11023
DPI
08/69
11020
DGZ
10/69
11020
EK0
10/69
11020
—
10/69
11024
FKN
11/69
11020
DWF
12/69
Phase I - Feasibility of a Periodic Flushing System
for Combined Sewer Cleaning
Demonstrate Feasibility of the Use of Ultrasonic
Filtration in Treating the Overflows from Combined
and/or Storm Sewers
Problems of Combined Sewer Facilities and Overflows,
1967, (WP-20-11)
Feasibility of a Stabilization-Retention Basin in Lake
Erie at Cleveland, Ohio
The Beneficial Use of Storm Water
Water Pollution Aspects of Urban Runoff, (WP-20-15)
Improved Sealants for Infiltration Control, (WP-20-18)
Selected Urban Storm Water Runoff Abstracts, (WP-20-21)
Sewer Infiltration Reduction by Zone Pumping, (DAST-9)
Strainer/Filter Treatment of Combined Sewer Overflows,
(WP-20-16)
Polymers for Sewer Flow Control, (WP-20-22)
Rapid-Flow Filter for Sewer Overflows
Design of a Combined Sewer Fluidic Regulator, (DAST-13)
Combined Sewer Separation Using Pressure Sewers, (ORD-4)
Crazed Resin Filtration of Combined Sewer Overflows, (DAST-4)
Storm Pollution and Abatement from Combined Sewer Overflows-
Bucyrus, Ohio, (DAST-32)
Control of Pollution by Underwater Storage
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