EPA-600/2-75-030
September 1975
Environmental Protection Technology Series
HATFIELD TOWNSHIP, PENNSYLVANIA
ADVANCED WASTE TREATMENT PLANT
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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EPA-600/2-75-030
September 1975
HATFIELD TOWNSHIP, PENNSYLVANIA
ADVANCED WASTE TREATMENT PLANT
by
Tracy W. Greenland
and
Fred R. Gaines
Tracy Engineers, Inc.
Camp Hill, Pennsylvania 17011
Program Element No. 1BB043
Project Officer
E. F. Earth
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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FOREWORD
Man and his environment must be protected from the adverse effects of
pesticides, radiation, noise, and other forms of pollution, and the
unwise management of solid waste. Efforts to protect the environment
require a focus that recognizes the interplay between the components
of our physical environment—air, water, and land. The Municipal
Environmental Research Laboratory contributes to this multidisciplinary
focus through programs engaged in
O studies on the effects of environmental contaminants
on the biosphere, and
O a search for ways to prevent contamination and to
recycle valuable resources.
This report details the engineering design, construction and operational
considerations that are necessary to provide advanced wastewater treat-
ment at a municipal facility.
A. W. Breidenbach, Ph.D.
Director
Municipal Environmental
Research Laboratory
iii
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ABSTRACT
The Hatfield Township, Pennsylvania Water Pollution Control Plant was
designed to encompass primary chemical treatment, secondary combined
activated sludge and nitrification facilities, tertiary chemical tube
clarification and mixed media filtration.
The operation of the facility demonstrated that the use of flow equaliza-
tion facilities improves plant operations by reducing and standardizing
chemical concentrations.
Phosphorus is removed efficiently in a combined primary-tertiary phase
with operations personnel having the flexibility to optimize each
process. Lime feed control by pH is easily accomplished although recir-
culation of primary sludges is not always necessary. Tube clarifiers
and mixed media filters combine to produce a highly polished effluent.
Nitrification was observed to some extent in this modified facility,
however, it was extremely difficult to control.
This report was submitted in fullfillment of project number 11060 FRQ by
the Hatfield Township, Pennsylvania, Municipal Authority, under partial
sponsorship of the Environmental Protection Agency.
xv
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CONTENTS
Page
Disclaimer
Foreword
Abstract iv
List of Figures v^
List of Tables viii
Acknowledgements xi
Sections
I Conclusions 1
II Recommendations 3
III Background 5
IV Advanced Waste Treatment 15
V Operational Programs 58
VI Operational Results 78
VII Experience With Existing Sludge Handling At The Hatfield
AWT Facility 120
VIII Construction Of Waste Treatment Projects 134
IX Project Costs 137
X Future Requirements 142
XI Critical Evaluation Of Hatfield Township Advanced Waste
Treatment Facility 155
XII References 161
XIII General Bibliography 163
XIV Appendices 164
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FIGURES
No_. Page
1 Regional Position of Hatfield Township 6
2 Area of Hatfield Township 8
3 Plan of 1965 Sewage Treatment Plant 11
4 AWT Plant Flow Diagram 26
5 Pump Station No. 1 and No. 2 32
6 Surge Storage System 34
7 Red Valve 34
8 Chemical Feed Building Flash Mix System 36
9 Lime Feed Schematic 38
10 Clariflocculator Tank 40
11 Aeration Tank 47
12 Secondary Clarifier 49
13 Rapid Mix-Flocculator Tank 51
14 Inclined Tube Modules 53
15 Pressure Filter 55
16 Backwash and Chlorine Contact System 56
17 Organization Chart-Initial Plant 59
18 AWT Plant Staffing 59
19 Operations Manual Page 63
20 AWT Plant Layout 71
21 Infiltration/Inflow Identification 77
22 Raw Sewage Flows—1973 94
VI
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FIGURES (continued)
— Page
23 Weekly Flow Variations 95
24 BOD5—Raw and Final 96
25 COD Values 97
26 Suspended Solids 99
27 Total Phosphorus Values 100
28 Total Soluble Phosphorus 102
29 Primary/Secondary Total Phosphorus Removals 103
30 Tertiary Total Phosphorus Removal 104
31 Ammonia-Nitrogen Values HI
32 BOD Removal Efficiencies 114
33 Suspended Solids Removal Efficiencies H5
34 COD Removal Efficiencies 116
35 Phosphorus Removal Efficiency 117
36 Sludge Thickener 144
37 Sludge Disposal System 145
38 Sludge Disposal Diagram 148
39 Adopted Sludge Disposal Diagram 150
40 Cost of Sludge Handling 151
VII
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TABLES
No. Page
1 Hatfield Township Municipal Authority Construction Costs—
1965 Project 12
2 Plant Operating Characteristics 1967-1970 13
3 Waste Discharge Limitations 16
4 Forms And Measurement Of Phosphorus, Conversion Factors 17
5 Primary PO^ Removal Tests 27
6 Hatfield Township Municipal Authority Aeration Tanks @ 3.6
MGD 45
7 Salary Schedules 60
8 Minimum Analysis Schedule—1973 69
9 Average Overall Removal Efficiencies; Percent 78
10 Composition Of Domestic Sewage 79
11 Summary Of Raw Sewage Characteristics 80
12 Raw Sewage Characteristics—1972 82
13 Final Effluent Values—1972 83
14 Raw Sewage Characteristics—1973 8^
15 Final Effluent Values—1973 85
16 Raw Sewage Characteristics—1974 86
17 Final Effluent Values—1974 87
•
18 Summary Of Plant Influent Flows 88
19 Summary Of Influent Plant Flows—1972 89
vixi
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TABLES (continued)
No. Page
20 Summary Of Influent Plant Flows—1973 90
21 Summary Of Influent Plant Flows: January-June 1974 91
22 March 1973 Recycle Flows 92
23 Raw Wastewater Suspended Solids: April 1973-March 1974 98
24 Average Total Phosphorus Values—April 1973-March 1974 105
25 Relationship Of Carbon Oxidation And Nitrogen Oxidation In
Wastewater Treatment 106
26 Fecal Coliform Analysis 112
27 Annual Operating Cost x $1000 118
28 Chemical Cost $/Million Gallons 118
29 Sludge Production-Estimated, June 1974 121
30 Sludge Production (Includes Recycles) July 1973-June 1974 121
31 Sludge Production, January-March 1973 122
32 Summary Of Sludge Operations, March 1973-June 1974 124
33 Sludge Operations-1974 Hours/Operations 125
34 Filter Press Test Data - November 1973 126
35 Centrifuge Tests - December 1973 Primary Sludge 126
36 Centrifuge Study - December 1973 Secondary Sludge 127
37 Centrifuge Study - December 1973 Tertiary (Alum) Sludge 128
38 Centrifuge Tests - December 1973 Secondary/Tertiary 128
39 Centrifuge Testing - December 1973 Combined Sludges 129
40 Ash Analysis - June 1973 131
41 Chemical Composition Of Incinerator Ash From Hatfield Town-
ship Municipal Authority AWT Facility - December 1973 132
42 Sludge Loadings - January-June 1974 133
IX
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No.
TABLES (continued)
Page
43 Hatfield Township Municipal Authority Construction Costs
1970 Project Advanced Waste Treatment Facility 139
44 Hatfield Township Municipal Authority Estimated Construction
Costs - 1973 Base 141
45 Summary Of Solids Handling Units, Program VII 149
46 Automatic Sampler Locations 158
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ACKNOWLEDGEMENTS
The support of the members of the Hatfield Township Municipal Authority
who served during the demonstration grant are acknowledged with sincere
thanks. These include as chairmen Charles Murgia*, and Roger Wittmer,
and as members Charles Hartley*, Allan Kulp*, James Piston, Ronald Newman,
Charles Sibel III*, Ralph Harvey, John Nunan and John Schankwieler, Grant
directors are indicated with an *.
Employees of the authority involved with the work included Roy B. Love,
Executive Director, Stephen Weech, Plant Manager and Laboratory Techni-
cians, Kenneth W. Mawson, Kathy Hughes, Cathy Love and Robert Lewis.
Preparation of this report was aided by Margaret Salinger and Mary Ann
Casper of Tracy Engineers and final typing was by Janice Gonczkowski.
Figures and graphs were by Frank Salinger of Tracy Engineers Inc. and
the authors.
XI
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SECTION I
CONCLUSIONS
The results of the demonstration grant performed at the Hatfield Township
Advanced Waste Treatment facility led to a number of conclusions, some
of which were positive, and some of which were negative.
1. The utilization of screening and grit removal ahead of the raw
sewage pump station would have lessened considerably operating
problems encountered in the significant grit accumulations in
the surge storage tanks, and the clogging of sludge recircu-
lation pumps by re-weaved, previously comminuted, rags and
fibrous material.
2. The use of surge storage tanks for flow equalization upstream
of the primary treatment system improves plant operations by
insuring regulated flow throughout the plant. In addition to
a regulated hydraulic flow, it also contributes towards a more
homogeneous blend of waste characteristics.
3. The surge storage tanks should have a more positive mixing
device than mechanical mixers, and the use of aerators would
not only tend to promote more vigorous mixing, but would supply
sufficient oxygen to retard septicity during the very warm
summer period.
4. The addition of lime to a pH of 9.5 in the primary flocculating
clarifiers resulted in primary phosphorus removals averaging
72.1%, an average overall phosphorus removal of 92.3%, and
average residual phosphorus of 4.68 mg/1 (primary effluent) and
0.54 mg/1 (plant effluent).
5. The use of submersible electrodes in the primary flocculation
chamber resulted in a daily operational problem requiring fre-
quent acid washing and recalibration of the probes. Only one
manufacturers probes were used, however, and new designs for
anit-fouling probes may eliminate this problem.
6. The aeration units reduced BOD5 and at certain times partially
reduced nitrogenous oxygen demand concurrently, albeit not
consistently.
7. The mixed-media filters removed approximately 50% of all sus-
pended solids fed to them. The tertiary tube clarifiers, how-
ever, removed the bulk of the secondary solids, resulting in
exceptionally low loadings of solids to the filters. Where
low phosphorus residuals, i.e., 0.75 to 1.5 mg/1 are all that
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is required, there may not be a necessity to utilize tertiary
filters after tertiary tube-type clarifiers. The presence of
tertiary filters, however, can polish not only phosphorus, but
suspended solids, and some BOD5 as well, and offer a final
protection to maintaining high effluent quality.
8. If tertiary filters are utilized after tertiary clarification,
provision should be made to by-pass the filters. Unit by-
passes throughout the process flowsheet are, and have been,
most useful at times of single process malfunction.
9. The flowsheet utilized at Hatfield Township consistently
produced a high quality effluent, even though in-plant recycle
flows, particularly from periodically overloaded sludge thick-
eners, at times exceeded original design calculations by
substantial amounts.
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SECTION II
RECOMMENDATIONS
As a result of the demonstration grant, certain items are recommended as
being immediately required to maintain the high level of operation
required, while other items are recommended for inclusion with the next
expansion stage, soon to be undertaken.
Those items suggested for immediate installation include:
1. The installation of floating aerators in the surge storage tank.
2. The utilization of different electrodes in the primary floccu-
lation units, either more advanced anti-fouling units, or flow-
through units.
3. The construction of a by-pass around the tertiary pressure
filters, such that full utilization of tertiary chemical pre-
cipitation can be realized, even with a malfunction in the
tertiary filtration system.
4. Modification or replacement of the existing vacuum filters to
provide both additional dewatering and incineration capabil-
ities through the development of a higher solids content in
the dewatered sludge.
5. Installation of liquid alum feed capabilities in the tertiary
chemical precipitation process.
Those items suggested for inclusion with the next expansion stage include:
1. The construction of raw sewage screening and grit removal ahead
of the raw sewage pumping station.
2. An increase in aeration detention time, in order to more con-
sistently achieve ammonia conversion in the aerators.
In addition to the above enumerated physical additions to the existing
Hatfield Township Advanced Waste Treatment Facility, the following items
are recommended:
1. Continuation of approximately the same level of laboratory
analysis work as was maintained during the demonstration grant
period as an operating tool. Effective laboratory control is
fundamental to achieving advanced waste treatment.
2. Institution of a more detailed preventive maintenance program,
3
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including adequate recording of pertinent data on equipment,
and the development of systematic maintenance schedules.
3. Continued operator training sessions on a scheduled basis,
to include not only the "what" of operation, but also the
"why".
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SECTION III
BACKGROUND
GENERAL
Hatfield Township is an Incorporated Municipality lying in Montgomery
County, Pennsylvania.
Hatfield Township lies on the fringe of the urbanized Philadelphia area.
In Figure 1, the general location of Hatfield Township with respect to the
Philadelphia urbanized area, is indicated. It may be noted from this that
Hatfield Township completely surrounds the small Borough of Hatfield, and is
adjacent to Lansdale Borough, as well as to a number of surrounding Townships
According to the U. S. Census Bureau, the population of Hatfield Township
in 1960 was 5,759. In the early 1960s, Hatfield Township was essentially
a rural community with some scattered residential development, and
virtually no industry, and only a very small amount of commercial activ-
ity. In 1960, there were no public sewer facilities and the entire
Township utilized individual well supplies as a source of water.
The study of Hatfield Township during the period of 1960 through 1973 is
typical of many of the communities lying on the fringes of highly urbanized
areas throughout the United States, which have increased dramatically in
population, and because of this population increase, have had to provide
a wide variety of essential services in a very short period. One such
service is that of sewage collection and treatment, which has grown from
no facilities in 1962 to highly advanced waste treatment in 1973.
COMMUNITY STATUS IN 1962
A Municipal Authority is a public device which has been created in
Pennsylvania, and in certain of the other states of the United States,
for the purpose of financing public works projects where State and local
limitations are placed on the borrowing capacity of local sub-divisions.
In Pennsylvania, a Municipal Authority has no restriction on the amount
of money it can borrow, providing that it can demonstrate adequate
revenues from user charges and other sources to pay debt service costs
as well as any operating expenses that are applicable to a project.
In 1961, the local governing body, the Commissioners of Hatfield Town-
ship, created the Hatfield Township Municipal Authority for the purpose
of investigating, and subsequently financing and constructing a sewage
collection system in Hatfield Township, and one or more sewage treatment
plants. This action was taken by the local political sub-division in
order to alleviate problems of malfunctioning septic tanks and other on-
lot individual sewage disposal systems, which were creating unsightly
conditions and health hazards in various built-up sections of the Township.
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HATFIELD TOWNSHIP
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URBANIZED AREA: Defined by U.S. Bureau of the Census, 1960
MONTGOMERY COUNTY PLANNING COMMISSION
Figure 1. Regional Position of Hatfield Township
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This action was taken in advance of any directives from the State regula-
tory bodies, and constituted an unusual situation, in that a community
undertook to solve its sewerage problems without any direct requirements
by the State regulatory bodies.
The Hatfield Township Municipal Authority was incorporated in 1961, and
proceeded to explore the problem of sewage treatment in the Township by
interviewing a number of engineers for the purpose of selecting a Con-
sulting firm to develop their planning. In the fall of 1962, Tracy
Engineers, Inc. was retained by the Hatfield Township Municipal Authority;
to initiate its planning program with respect to sewerage.
This initial planning involved consideration of the then applicable
zoning and land use planning in the Township; the attitudes of the local
elected officials with respect to future growth and its impact on other
municipal services; projections of growth developed by County and Regional
Planning Commissions; and the requirements of the State regulatory
agency with respect to the degree of waste treatment necessary.
PRELIMINARY REPORT
The initial thinking of the Hatfield Township Municipal Authority, shortly
after its formation in 1961, centered around the possibilities of providing
separate sewerage treatment plants for two built-up areas of the Township.
In Figure 2, a more detailed location plan of Hatfield Township is
indicated together with the surrounding communities. In 1962 there were
two existing sewage treatment plants in the general area; one servicing
Hatfield Borough indicated by location "C" in Figure 2, and the other
service Lansdale Borough, indicated by location "D". The Hatfield
Township Municipal Authority originally felt that it desired to see
construction of small seperate treatment facilities at location "B" and
location "A", being at the points of the only significant areas of
concentrated development within the Township at that time.
In a report presented to the Authority in January 1963, the consultant
advanced the proposition that Hatfield Township offered significant
potential for future development, even though areas of concentration
were limited to two general locations at that time, and that the logical
location of a single sewage treatment facility to service the entire
Township would be at point "A", as shown on Figure 2. The Hatfield
Borough plant (point "C") had been constructed some years earlier, and
consisted of Imhoff tanks and standard rate trickling filters, and
appeared to be adequate for servicing the needs of Hatfield Borough for
a number of years in the future. The Lansdale Borough sewage treatment
plant (point "D") was a primary treatment facility constructed in the
1930s, which was overloaded and could not accept any sewage flows from
any portion of Hatfield Township.
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FRANCONIA
TOWNSHIP
HILLTOWN
TOWNSHIP
/f^HATFIELD
/ VTOWNSHIP
MONTGOMERY
TOWNSHIP
UPPER NESHAMINY
DRAINAGE AREA
Figure 2. Area of Hat field Township
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While the Hatfield Borough plant (point "C") could, perhaps, have pro-
vided temporary treatment capacity to portions of Hatfield Township,
north, and east and west of the community, local political consideration
dictated that they did not desire to enter into any arrangement with the
Township at that time. Therefore, the obvious conclusion of a single
treatment facility for the entire Township at point "A" was finally
accepted by the Authority as the basic premise in their sewerage planning
program.
This location also would be ideally suited to providing future service
to the total area which drained to the site, including portions of
Hilltown Township, which lay in an adjacent County, and both Lansdale
Borough and Hatfield Borough. The development of comprehensive regional
waste treatment was not a consideration in 1962, but its potential in
later years had to be one of the points considered in the selection of
the site for the treatment facility.
LEGAL DIFFICULTIES
Following completion of the preliminary report and its approval by the
Hatfield Township Municipal Authority, the detailed design of the project,
including a secondary sewage treatment plant and interceptor and collector
sewers, proceeded rapidly. The project was ready for advertisement and
bidding in the late spring of 1963. The bidding actually took place,
but the implementation of construction was stopped by legal action
brought by a number of tax-payers against the local governing body and
the Authority.
As was not uncommon in the early 1960s, citizens' groups agitated against
sewage treatment and its imposition of user charges as a replacement for
on-lot sewage disposal units of an individual nature. The legal problems
delayed the project for two years, but the Supreme Court of Pennsylvania
ultimately ruled in favor of the Authority, and the project proceeded
to a second bidding stage in early 1965, and contracts were awarded and
construction commenced in May 1965.
During this period between 1963 and 1965, certain sewer lines were
constructed to service a new secondary school, and were temporarily
connected to the Hatfield Borough system. These new sewer lines were
then disconnected from the Borough system in 1966, and formed a part of
the total collection system constructed as part of the 1965 project.
1965 PROJECT CONSIDERATIONS
At the time of the design of the 1965 project, consulting engineers were
under strict requirements to conform to a "Sewerage Manual", published
by the Pennsylvania Department of Health, which provided design para-
meters for all types of sewage treatment facilities. In those days, the
procedure to be followed in the design of a project involved initial
meetings with regional engineers for the Pennsylvania Department of
Health having jurisdiction over a specific geographical area. In these
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initial meetings, design concepts were discussed and the general design
details were developed. Strict adherance to the requirements of the
Sewerage Manual was a very definite factor in the selection of the
process, and in the sizing of units.
The original 1965 plant was a secondary treatment plant, utilizing a
main pump station with three raw sewage pumps, two drag-chain type
primary clarifiers, a two-compartment common wall aeration tank with
diffused air, two three-phase separation secondary clarifiers, and a
contact chlorine tank, as shown in Figure 3.
This original plant was sized for an average daily flow, according to
the requirements of the Pennsylvania Department of Health in their
Sewerage Manual, at 0.9 mgd (3,406.5 m3/day). The maximum rate of flow
was anticipated at 1.35 mgd (5,110 m3/day, and a peak rate of flow of
1.8 mgd (6,813 m3/day).
Based upon rational design criteria, however, this first plant project
had an average daily flow capacity of 1.3 mgd (4,920.5 nrVday)•
This ability to absorb a hydraulic loading in excess of normal design
parameters at that time was based upon a conservative design of overflow
rates for the primary and secondary clarifiers, and the fact that the
Sewerage Manual required a six hour detention time in the aeration tanks
as the fundamental design parameter, without regard to the mode of
operation of the unit, the mixed liquor suspended solids, or any other
factor which would demonstrate a lower total detention time requirement.
The total loadings were 1,530 pounds per day of BOD5 (694.6 kg/day), and
1,800 pounds per day of total suspended solids (817.2 kg/day).
In addition to the hydraulic units at the treatment facility, there was
provided a complete solids handling system, which included a sludge
holding tank, or sludge thickener, vacuum filtration equipment, and a
multiple hearth incinerator. The solids handling equipment was provided
with a capacity three times that of the average rational daily design
flow, or 3.6 mgd (13,626 m3/day). It was the intention that the solids
handling would operate on a oneshift basis up to the average daily flow
of the plant, and upon future hydraulic expansions, could begin to
operate on a second, and even a third shift per day, thus precluding the
necessity of additional capital construction in the solids handling area
when growth requirements dictated hydraulic plant expansions.
Inasmuch as the initial sewage treatment plant, constructed in 1965, was
constructed concurrently with a new sewage collection system for the
community, the only mode of pretreatment provided ahead of the main raw
sewage pumps, was comminution. No facilities were provided for grit
removal, nor for screening of gross solids and rags. This was a quite
common practice in the United States in the middle 1960s, when an
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FW WOOOWADD
Figure 3. Plan of 1965 Sewage Plant
11
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entirely new system was placed in operation, inasmuch as the new condi-
tion of sewage collection lines was assumed to preclude the entrance of
large amounts of grit into the sewage treatment plant process.
In Figure 3. a general layout plan of the Hatfield Township sewage
treatment plant as it was constructed in 1965, is shown.
CONSTRUCTION OF 1965 PROJECT
The original Hatfield Township sewage treatment plant, commonly known as
"The 1965 Project", was started in the construction phase in June 1965,
and was officially certified as completed in August 1966. Portions of
the plant were placed in operation during the summer months of 1966, and
by the first part of 1967 the plant was in full operation, with virtually
all of the initial operating problems resolved.
This 1965 project, as it related to the construction of the sewage
treatment plant, had a total construction cost of $848,767- In Table 1,
which follows, the construction costs for the 1965 sewage treatment
plant are shown in more detail.
The net project cost, after deduction of a Federal Grant, was financed
by the Hatfield Township Municipal Authority through the sale of Author-
ity Revenue Bonds to the general public, through a Bond Underwriting
firm. Included in the total Authority Bond issue of $2,700,000, was the
cost of providing interceptor sewers and collecting sewers throughout
the entire township not sewered in 1965.
TABLE 1. HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
CONSTRUCTION COSTS - 1965 PROJECT
SEWAGE TREATMENT PLANT
General Construction $745,844
Plumbing Construction 26,289
Heating (Ventilating) Construction 13,300
Electrical Construction 63,334
TOTAL 1965 TREATMENT PLANT CONSTRUCTION COST $848,767
OPERATION OF 1965 PROJECT
As indicated previously, the sewage treatment plant for which construc-
tion was commenced in the spring of 1965, was placed in full operation
12
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in September 1966. From the period September 1966 through the early
part of 1967, connections were being made to the new sewage collection
system throughout the Township, and full connection and subsequent
development of total flows did not actually fully occur until early
1968.
The initial operation of the new facility in the fall of 1966 encount-
ered the usual operating problems, including those occasioned by the
hiring of a new work force, generally unfamiliar with this type of
operation. However, by 1968, the initial operating difficulties had
been resolved and the plant was in sound operating condition.
In Table 2, plant operating characteristics are indicated for the period
of late 1967 to early 1970. The only parameters required for reporting
to the State regulatory agency were BOD and Suspended Solids.
TABLE 2. PLANT OPERATING CHARACTERISTICS
HATFIELD TOWNSHIP SEWAGE TREATMENT PLANT
1967 - 1970
BOD5 Raw, mg/1 227
BOD5 Effluent, mg/1 13
% BOD Removed (19 samples) 94
Suspended Solids Raw, mg/1 171
Suspended Solids Effluent, mg/1 12
% Suspended Solids Removed (16 samples) 93
Average D.O. in Effluent, mg/1 9.6
Phosphate (PO^) Raw, mg/1 23
Phosphate (PO^)*Effluent, mg/1 10
% Phosphate (PO,/,.) Removal (11 samples) 56.5
The average daily flow during this period approximated 660,000 gpd
(2,498 m /day), or approximately onehalf of the rational design capa-
city. As can be seen by an inspection of Table 2., the degrees of BOD
removal and suspended solids removal exceeded 93%
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While phosphorus was not a required parameter in the late 1960s, the
data for the removal of phosphate is indicated in Table 2., as being
approximately 56.5%. This represented an upper limit which could be
theoretically achieved by the activated sludge process utilizing some
form of solids handling other than sludge digestion.
At the time of the design of the advanced waste treatment facilities,
the existing sewage treatment plant at Hatfield Township was producing a
high degree of BOD and suspended solids removal, and a very commendable
percentage of phosphate removal, but the facility was operating at about
one-half of its capacity. Nevertheless, the operation of the facility
represented an achievement of efficient operation ranking in the very
upper portion of those treatment plants in operation at that time in the
United States.
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SECTION IV
ADVANCED WASTE TREATMENT
GENERAL
About the time of initiation of construction of the 1965 Hatfield project,
the Federal Government began consideration of more stringent guidelines
for effluent discharge from sewage treatment facilities. In particular,
the Federal Water Quality Administration began to consider limiting efflu-
ent values versus the prior and common practice of establishing simply a
percentage removal. Under the old manner of operation, primary treatment
was generally considered to be that which provided 35% BOD removal and up
to 60% suspended solids removal, and secondary treatment was considered to
provide between 85% and 90% BOD removal and 90% to 95% suspended solids
removal. Any other treatment beyond secondary treatment, such as the use
of slow sand filters, polishing ponds, or the like, were given no special
name or consideration, and were infrequently used.
In the middle and late 1960s, attention focused on the condition of many
fresh water lakes throughout the United States, and in particular, the
five Great Lakes. Of prime concern was the very advanced deterioration
of Lake Eire, and the Federal Water Quality Administration conducted a
number of seminars in the Great Lakes Basin, aimed at disseminating
technology then available on nutrient removal from waste water which
would lessen the impact on the lakes, and would permit them to reverse
the trend of decay which had been accelerating for a number of years.
Concurrently with the Federal studies, the State of Pennsylvania began
to classify each and every stream in the State, and among the very first
to be so classified was the Neshaminy Creek, into which the effluent
from the Hatfield Township sewage treatment plant discharges. New
limiting effluent quality criteria were published in July 1967 for the
Neshaminy Creek Basin, and constituted the first such criteria promul-
gated within the State of Pennsylvania. Because of the size of the
stream into which the discharge is made, and because of the large number
of communities utilizing this stream, the limitations which were estab-
lished were extreme in nature and exceeded any of those previously
published throughout the United States, excepting where actual physical
discharge was completely eliminated from a surface water.
SANITARY WATER BOARD ORDER OF 1967
On July 1, 1967, the Sanitary Water Board issued an Order to the Hat-
field Township Municipal Authority setting waste discharge limitations,
and requiring that a preliminary study be completed and submitted to the
State of Pennsylvania on or before July 1, 1968, indicating how the com-
munity intended to meet the new waste discharge limitations.
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The new waste discharge limitations, as published in July 1967, are
reproduced in Table 3.
The standards set in this Order were most stringent, and appeared, in
1967, to be somewhat contradictory. They were not in general keeping
with other standards which had been published for other areas, notably
in areas such as the Lake Michigan drainage basin.
TABLE 3. WASTE DISCHARGE LIMITATIONS
HATFIELD TOWNSHIP
Monthly
Average Value, Maximum
Not More Than: Single Value
5-Day BOD 4 mg/1 10 mg/1
Coliform Organisms:
Date: 5/15 - 9/15 of Any Year 100/100 ml
Date: 9/16 - 5/14 of Any Year 1,000/100 ml
Suspended Solids 15 mg/1
Total Soluble Phosphate (PO^) 0.2 mg/1
Dissolved Oxygen
2,400/100 ml
20,000/100 ml
50 mg/1
1.0 mg/1
Not Less Than 5 mg/1 at Any Time
The specific criteria developed in the Order from the Sanitary Water
Board, and reproduced in Table 3., requires some individual comment.
The first criteria of a maximum of 4 mg/1 of 5day BOD as a monthly
average, and a maximum of 10 mg/1 of 5day BOD at any one time, required
that the effluent be virtually suspended solids free. It also required
virtually total conversion of both carbonaceous and nitrogenous BOD, and
most probably, the utilization of a tertiary filtration step, in order
to capture as much of the suspended solids as possible. The limitation
of a monthly average value of not more than 4 mg/1 appeared, at least in
1967, to be unrealistic, in that the accuracy of the 5day BOD test was
not considered reliable at such low values.
The total suspended solids limitation of a 15 mg/1 maximum as a monthly
average value, and a maximum of 50 mg/1 at any one time, appeared to be
completely inconsistent with the BOD limitation. It appeared, theoret-
ically, that a waste effluent containing 15 mg/1 suspended solids could
not possible produce a 4 mg/1 BOD concentration.
16
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The criteria for coliform organisms began its introduction in the United
States with this Order, and relies primarily upon Post-chlorination as a
means of achieving the limiting values. This is not a particularly
difficult situation, inasmuch as post-chlorination is a widely utilized
concept throughout the United States, and has been required by a number
of the States for many years.
The criteria for total soluble phosphate (P04) was the most stringent
requirement, and the one which appeared to be very much in need of
modification. This limitation of 0.2 mg/1 of total soluble phosphate in
the effluent as a monthly average, would be extremely difficult to
achieve, as would even the upper limit of 1.0 mg/1 at any one time. It
was pointed out to the State regulatory agency in 1968 that the then
current standards in other areas of the country, and as suggested by the
Federal Water Pollution Administration, provided for a minimum of 80%
removal of phosphorus as P.
Investigators in sanitary engineering expressed the results of phosphorus
analysis as P (phosphorus) and not as P04 (phosphate) , or PoC>5 (phosphorus
pentoxide). The relationship between the various forms are shown in
Table 4.
Reference to this table will indicate the relationship between P04 and
P, to be P04 x 0.327. Thus, the requirement of the Sanitary Water
Board, expressed as phosphorus (P) would be 0.065 mg/1 P as a monthly
average value, and not more than 0.33 mg/1 P at any time.
TABLE 4. FORMS AND MEASUREMENT OF PHOSPHORUS,
CONVERSION FACTORS
In water analyses all measurements should be reported as mg/1 of P.
To Convert X to P To Convert P to X
Multiply By: X Multiply By:
1.00 P 1.00
.451 P205 2.29
.327 P04 3.06
.316 H3P04 3.16
.200 Ca3(P04)2 5.00
.181 Ca5OH(P04)3 5.51
17
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In the report prepared at the request of the Hatfield Township Municipal
Authority for presentation to the State regulatory agency in June 1968,
it was indicated that the technology then prevailing would preclude
meeting this effluent limitation. As a matter of evolvement over the
past several years, the State regulatory and Federal regulatory agencies
have informally agreed that this criteria cannot be consistently achieved
although they have not modified the actual written requirements. When
the 1970 project was designed and submitted for State and Federal
approval, the statement was made that the phosphate limiting criteria
could not be met, and it was indicated that the Authority would meet the
0.2 mg/1 as P04 fifty percent of the time, 0.5 mg/1 as P04 seventy-five
percent of the time, and 1.0 mg/1 as P04 one hundred percent of the
time. Although this was never formally acknowledged by the State and
Federal regulatory agencies, the permit to construct the new facility
was issued on the basis of the information submitted.
1968 REVIEW OF CURRENT TECHNOLOGY ON PHOSPHORUS REMOVAL
As part of the report published in June 1968 for submission by the
Hatfield Township Municipal Authority to the Pennsylvania Department of
Health, a review of the then current technology on phosphorus removal
was included. This review of the then current technology was the result
of an intensive literature search, attendance at a number of Great Lakes
Basin seminars conducted by the Federal Water Quality Administration,
and discussions with the leading equipment manufacturers, as to the most
current technology then being produced by them, or being considered for
production through their research work.
In order that the reader may have some indication of the thinking which
lay behind the development of the Hatfield Township advanced waste
treatment plant design, there is included in this portion of the study,
a complete reproduction of the data presented in 1968 to the State
regulatory agency concerning the review of the then current technology
on phosphorus removal. As the reader considers this information, he
should be reminded that this information was written in 1968, and at
that time the technology on phosphorus removal was severely limited, and
was generally confined to laboratory and bench-scale studies, with the
exception of the advanced waste treatment facility at South Lake Tahoe,
California.
The following is a direct quotation from the 1968 report, as submitted
by the Hatfield Township Municipal Authority to the State regulatory
agency.
"A review of past thinking in the wastewater field
reveals that intermittent attention has been paid, until
the last three or four years, to any parameters for waste
discharge acceptability other than the popular BOD and
suspended solids criteria.
That there is a need for additional parameters has
been recently amply demonstrated. <^' ' ' Sawyer, (5)
18
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indicated that 'In any system of nutrient control, phos-
phorous removal is considered absolutely essential
because of the ability of certain blue-green algae to
fix nitrogen gas (atmospheric nitrogen) contained in the
water The degree of (algae) control to be expected
will depend in large measure on the percentage of total
input to a lake that can be eliminated or removed'."
The attention focused on the need for nutrient removal has resulted in a
current, rather large-scale investigation program by many individuals
into the most effective means of removing phosphorus from waste dis-
charges. Virtually all of the present studies are being conducted in
the laboratory, with some pilot plant work having been completed in the
field. Full-scale plant investigations of the problem are just now
emerging.
One of the prime considerations in phosphorus removal is that phosphorus
is conserved throughout the entire waste treatment process, that is,
there is no net loss through treatment. Phosphorus enters a treatment
process in its highest oxidized form, and no common biological systems
can reduce phosphate. Phosphorus removal is probably a combination of
cellular growth and inorganic solubility, and is associated with the
sludges formed in the treatment process.(6)
The past approaches to the phosphorous problem centered mainly around
attenpted control by biological means, and attempted control through
adjustment of the mineral composition of the effluent to precipitate
phosphorous. A more recent approach has been to blend chemical precipi-
tation with active biological solids. Another recent approach has been
chemical treatment or raw wastewater through the use of specifically
lime.
Considering biological methods of phosphorus removal, one of the most
detailed studies was conducted in 1964 by Levin & Shapiro.^ ' They
demonstrated that biological uptake of orthophosphate in excess of that
required for cellular growth is possible, and termed this fact"luxury"
uptake. Their studies, which included both laboratory and field plant
studies, indicated that dissolved oxygen is essential to, and exerts
profound control, over orthophosphate uptake, and that the rate at which
oxygen is applied greatly affects the uptake capacity of the sludge
organisms. They also found that in wastewater treatment plant opera-
tion, dissolved inorganic orthophosphate leaches out of sewage organisms
when the dissolved oxygen level of the sewage is permitted to fall. If
there is insufficient aeration, the leakage may occur in the aeration
basin. If there is sufficient oxygen in the aeration basin, the leakage
will occur in secondary settling, as the sluge blanket rapidly consumes
available dissolved oxygen. It appears that the pH of the mixed liquor
in the aeration basin vitally affects orthophosphate uptake, with a
maximum uptake occurring in the pH range 7.0-8.0. A small amount of
return sludge in raw sewage significantly improves the orthophosphate
uptake.
19
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An evaluation of a full-scale plant operation utilizing biological
control has been reported in detail by Vacker, etal.(8-> This evaluation
of the San Antonio, Texas wastewater plant revealed that in excess of
87% of the phosphorus was removed through the biological process. Vacker
reports that there are four requirements for effective phosphorus removal;
first, the incorporation of the phosphates into the solids of the system;
second, the production of enough solids of high phosphate uptake capacity;
third, removal of solids from the system; and fourth, non-return of
phosphate-containing degradation products of the solids removal. It was
reported that an optimum rate BOD/aeration solids loading should be in
the range of 50 Lb. BOD/100 Lb. of aeration solids, and that avoidance
of long retention of solids in the secondary clarifiers during low flow,
through the use of a sludge return surge tank, was important. Also
reported, was the fact that rate of raw waste flow controlled to provide
the optimum BOD/aeration solids loading, through the use of surge tanks,
appeared to be vital. Vacker further indicated that it was necessary to
maintain a DO in the aeration such that the DO does not drop below 2
mg/1 in more than half the tank, and reaches a level of about 5 mg/1 at
the effluent end. This must be accomplished, however, while avoiding
over-aeration, which would result in excessive nitrification and aerobic
digestion of solids. The phosphate rich waste activated sludge must be
disposed of completely apart from primary and secondary processes.
This study was an attempt to determine why the San Antonio Rilling Plant
produced such a high phosphorus removal, when eight other plants in
Texas, with approximately the same BOD and Suspended Solids efficiencies,
were removing only 9% to 55% of the phosphorus. Bunch(2) indicates that
anticipated phosphate removal through biological means in an activated
sludge plant is in the range of 30-50%, with the latter a maximum. The
operation at San Antonio, and a similar operation in Baltimore, Maryland,
consistently produce higher phosphorus removals, for reasons that are
not yet entirely clear.
Bunch(2) suggests that among the variables, aeration rates of 3 to 7
cfm/gal., and detention times of 4 to 6 hours appear to be desirable,
with aeration rates being probably more critical. He further suggests
avoidance of excessive phosphorus leakage in secondary clarifiers can be
best accomplished if solids detention in these units is maintained at
less than 30 minutes.
In another approach to phosphorus removal, that of adjustment of the
mineral composition of the biological effluent to precipitate phos-
phorus, Brunner(9) reported on studies using lime and alum. This
approach represents the tertiary approach, that of following conven-
tional treatment with a third stage process intended specifically to
reduce phosphorus content.
When lime is used as the precipitate, the equipment used is the same as
that utilized in lime softening of water, i.e., up-flow clarifiers with
recycle of sludge. Filtration following settling improves phosphate
removal.
20
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The lime dosage must be determined specifically for each application,
since it is affected by concentrations of other materials in the water,
especially bicarbonate alkalinity. Experimental results indicate phos-
phate removal improves with increasing pH. At pH 9.0, results have been
obtained at 80% removals. The pH of the lime treated water is likely to
be too high for direct discharge without recarbonation. In large plants,
it may be practical to calcine the sludge and recover usable lime.
Where alum is used as the precipitate, the equipment should be the same
as that used for alum clarification, i.e., a horizontal flocculator-
settler arrangement. Use of filters after settling will increase the
phosphate removal, but it appears that the 80% removal can be achieved
without filtration.
The alum dose is difficult to predict, but may be on the order of two
parts of aluminum by weight, per part of phosphorus. For very high
degrees of phosphate removal, the ratio is four to one. For municipal
secondary effluent, the required dose of commercial alum is likely to be
200 mg/1 or more for 80% phosphate removal. The sludge formed is vol-
uminous and of low density, and presents handling problems.
Another tertiary process of importance is that now in operation at Lake
Tahoe, California, and reported by Gulp, R. L. & Roderick.(10) This
plant employs a patented process which includes two fundamental steps.
The first is the removal of the particulate matter by chemical coagula-
tion, and removal of the resulting precipitate by means of filtration.
The filtration is accomplished on separation beds, utilizing filter
media blended hydraulically to produce an overall media that decreases
in void space from coarse to fine in the direction of filtration. The
second step involves adsorption of dissolved matter on granular activated
carbon, using carbon columns. Carbon regeneration equipment is provided
at the plant to reactivate the exausted carbon for reuse. The initial
operations utilized alum for the chemical precipitation, and at an
average dosage, achieved a final phosphate content varying between 0.1
and 1.0 mg/1. BOD removals were accomplished to less than 1 mg/1, sus-
pended solids to less than 0.5 mg/1, and the coliform removal was to
less than 2.2 MPN/ 100 ml.
Additional data on the South Tahoe plant has been reported by Slechta
and Gulp, G. L.(H) Pilot studies on the use of lime as the chemical
precipitant reveal similar material concentration percentage removals.
In addition, the use of lime raises the pH to a point where pilot
studies were run on ammonia stripping, in a stripping tower, as a
combined means with the existing process, of phosphorus, nitrogen and
organic treatment in one plant.
Another approach to the phosphorus removal problem has been studied by
several persons. This method involves lime treatment of the raw waste-
water ahead of the biological process. Buzzell & Sawyer(12) report that
lime treatment of raw water can effect an 80% to 90% removal of total
21
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phosphorus with a better than 97% removal of soluble inorganic forms.
This same treatment can remove 50% to 70% of the BOD, almost 25% of the
nitrogen, and 99.9% of the coliform bacteria. The lime requirement is
independent of the phosphorus content and can be estimated in terms of
the alkalinity. Lime dosage can be controlled by pH measurement, and
for each situation, the optimum pH must be determined. The volume of
sludge produced in lime treatment is approximately 1% of the volume of
wastewater treated, and may require chemical conditioning to improve the
filterability of the sludge.
In connection with the removal of phosphorus by precipitating raw waste-
water with lime, Albertson & Sherwood(13) have reported in detail.
Their findings indicate that there are two fundamental recognized rela-
tionships; first, the chemical dose for phosphate removal is controllable,
and depends upon the desired residual phosphate concentration, and not
necessarily the initial phosphate concentration; and second, biological
phosphate removal is difficult to control and depends upon the needs of
the activated sludge cell, and is independent of the phosphorus concen-
tration—as long as a phosphate deficiency does not exist. Tertiary
treatment does not appear to allow for an optimum combination of these
two fundamentals. It allows the activated sludge to extract the re-
quired amount of phosphorus, and then requires chemical removal to the
desired residual phosphorus level. In a patented process, Albertson &
Sherwood extract phosphorus to a specific concentration by lime preci-
pitation of the raw sewage, then the activated sludge process is used to
extract the remaining phosphorus to reach the desired level.
It is reported that this patented approach reduces chemical costs in the
range of 60%-70%, over tertiary chemical precipitation. It was also
reported that solids recirculation around the primary unit would enhance
clarification, and that as much as 25% more phosphate is removed with
recirculation than with straight chemical precipitation. A secondary
effect of recirculation appeared to be a much clearer overflow liquor,
which resulted in even lower BOD addition to the secondary system.
It is reported that the lime must be added to the flocculator-settling
unit at a pH of 9.0 to 10.0, depending on waste characteristics. The
majority of the phosphate, 85% of the suspended solids and 65% -75% of
the raw BOD is removed in this stage. It has been estimated that in
some cases, the requirement for recarbonation may be eliminated through
the release of C02 in the activated sludge system.
It appears that sludge handling and dewatering may benefit from this
approach, since it practically eliminates conventional chemical costs
for sludge dewatering units because of the CaC03 in the raw sludge.
There are underway other investigations as to alternative methods of
phosphorus removal. Cohen(14) has reported on utilization of activated
alumina and lanthanum as precipitants. He has also reported on consid-
22
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eration of ion exchange, the use of soil systems, and utilization of
reverse osmosis as potential means of achieving acceptable phosphorus
removals. He also mentions up-flow clarification through a sludge
blanket as an alternative device. His conclusions are that none of
these alternatives are now ready for application, although research will
almost certainly make some of those alternatives useful for application
in specialized instances.
This brief review of current technology on phosphorus removal is intended
to provide only a general indication of the various methods which might
be applied to solving Hatfield Township's problem. It must be recognized
that much of the data discussed is undergoing further analysis, and
pilot and field sutdies, and that other methods of phosphorus removal
will undoubtedly be investigated and may prove quite practical. It is,
unfortunately, impossible for Hatfield Township, or any other community
in the Neshaminy Basin, to sit by until the picture has clarified and
the processes discussed herein have been fully proven beyond question.
It is virtually impossible to assume that one single process will evolve
as the answer to the problem. Almost all of the current technology is
based on studies of aeration processes, with little work having been
done on trickling filter plants. The problems of trickling filter
operation most certainly will indicate that many of the processes
reviewed will be unsuitable.
At a recent Seminar on phosphorus removal, conducted by the Federal
Water Pollution Control Administration, it was repeatedly mentioned that
individual factors, such as flow, waste composition, industrial waste
volumes and character, the type of facility, and operating technology,
must seriously affect the choice of method at each individual plant.
There is not now just one answer, nor does it appear that there will be
evolved a singular approach to the problem.
SELECTION OF PROCESS
The selection of the treatment process to achieve the effluent limit-
ations previously presented in Table 3., involved a thorough analysis of
the literature search, as presented in the previous section, the avail-
ability of equipment, and evaluation of the then current thinking of
those engineers who were in the forefront at that time in advanced waste
treatment technology.
It was finally decided that the most suitable approach to the problem
would be that of chemical precipitation of the raw wastewater with lime,
followed by a complete-mix activated sludge process, and the inclusion
of a tertiary step, involving alum addition, and then filtration through
a mixed-media filter bed.
The reasoning which resulted in this selection included the following:
1. An expanded hydraulic capacity at the new advanced waste
-------
treatment facility would be required by reason of the
rapid growth in the service area, and new primary units
would be necessary. It was anticipated that significant
savings could be realized by combining clarification and
flocculation in the same unit.
2. The chemical precipitation of new wastewater would result
in a high degree of phosphorus removal in the primary
cycle, as well as a high percentage of organic removal.
3. The complete-mix aeration could be designed to function at
a much lower organic loading, and the phosphorus could
further be reduced by the action of biological up-take.
4. The tertiary step, including chemical addition, mixing,
flocculation, settling and filtration, was required to
effect the lowest possible phosphorus content, but pro-
viding for chemical precipitation in both the primary
and tertiary stages, a maximum of flexibility in operation
could be available, such that the optimum could be
obtained between phosphorus removal and chemical costs.
Once the selection was made as to the processes, the further decision was
made to provide surge storage, or flow equalization, and control the flow
throughout the entire plant. A degree of controlled flow was a require-
ment for the filtration phase of the tertiary step, and it was apparent
that since it was necessary at some point in the flowsheet, the primary
and secondary stages would benefit considerably by its inclusion at the
beginning of the initial process.
The total project, as finally evolved, resulted in the following:
1. Additional raw sewage pump station.
2. Primary surge storage or flow equalization in duplicate
units, with the existing primary clarifiers converted to
service as auxiliary surge storage tanks.
3. Duplicate circular primary clarifier-flocculator units.
4. An additional aeration basin of the same size as the
existing unit, with the existing unit modified to permit
complete-mix operation.
5. Duplicate rapid sludge removal secondary clarifiers.
6. The tertiary step, involving:
a. Mixing, flocculation, and settling in duplicate
units, with the settling being accomplished in
tube-settlers.
24
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b. Filtration through mixed-media filters.
7. Chlorine contact, accomplished by slightly modified
existing secondary clarifiers, which would also serve
as filter backwash storage tanks.
8. A new sludge thickener, with the existing sludge holding
tank to be retained for stand-by use.
9. A chemical feed building, which would be combined with
the surge storage tank and primary clarifier-flocculator
construction, and would house the flash mixing facil-
ities and the lime feed equipment, as well as sludge
recirculation pumps and sludge draw-off pumps. A bulk
lime storage silo, adjacent to this chemical feed
building, was provided.
10. A filter building which would house the mixed-media
pressure filters, as well as tertiary chemical feed
equipment, secondary sludge return pumps, waste acti-
vated sludge pumps, and tertiary filter influent pumps.
11. Utilization of the existing sludge handling facilities,
including vacuum filtration and incineration, without
additional modification.
In 1968, it was anticipated that when hydraulic flows
reached 2.5 mgd (9,462.5 m3/day) that additional sludge
handling facilities would be required. This was antici-
pated because the character of the sludge would change
with the use of lime in the primary cycle.
A plan of the 1970 advanced waste treatment plant is shown in Figure 4.
BENCH SCALE TESTING
Throughout the period when the selection of the process for the new Hat-
field Township advanced waste treatment facility was under consideration,
numerous testing of alternative means of phosphorus removal were simulated
in the laboratory. Once the selection of the process was made, and it was
determined that the major emphasis on phosphorus removal would be in the
primary lime precipitation step, a series of tests were performed at the
existing Hatfield Township plant in October 1968, to determine the chemical
addition required to provide the optimum phosphorus removal in the primary
cycle. These tests are summarized in Table 5.
The data developed in Table 5. proved to be most interesting. The Hatfield
waste is high in alkalinity, averaging slightly in excess of 400 mg/1. The
lime addition of 185 mg/1 indicated a reduction in PO^ to a 3-4 mg/1 range,
which it was anticipated would be further reduced by about 50% in the
25
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(.EXISTING SLUDGE TANK
2.EXISTING DISTRIBUTION BOX
}.BACKWASH STORAGE TANK 2
4.BACKWASH STORAGE TANK I
5.BACKWASH PUMP VAULT
6.BACKWASH STORAGE TANK 3
7.AUX SURGE STORAGE TANK
8.AERATION BASIN HEAOBOX
9.FINAL CLAREFIER HEAOBOX
IO.FLOCCULATION TANK 3
II.FLOCCULACION TANK 4
12.CHEMICAL WASTE SLUDGE PUMP VAULT
13.PRESSURE TrPE MIXED MEDIA FILTERS
HATFIEIO TOWNSHIP MUNICIPAL AUTHORITY
ADVANCED WASTE TREATMENT PLANT
Figure 4. AWT Plant Flow Diagram
-------
TABLE 5. PRIMARY P04 REMOVAL TESTS
Jar
Test Sludge
Date No. Recycle, % pH
10/28/68 Raw
Filter
IA
IB
1C
ID
IE
IF
II A
IIB
IIIA
IIIB
IVA
IVB
10/28/68 Raw
Filter
IIC
I ID
HE
IIF
10/29/68 Raw
Filter
VA
VB
VC
VD
VE
VF
VIA
VIB
VILA
VIIB
VI HA
VIIIB
VIC
VID
VIE
VIF
0
0
20
20
50
100
—
:
—
20
20
50
100
0
0
20
20
50
100
—
-
-
7.5
7.5
9.5
9.5
9.45
9.45
9.40
9.45
10.1
10.1
11.65
7.5
9.9
9.95
7.4
7.4
9.45
9.45
9.40
9.45
7.95
7.95
10.3
10.35
9.95
10.10
10.0
9.95
9.36
9.4
9.8
9.8
10.9
10.85
10.05
10.10
10.05
10.05
Analytical
Polyelect- Determination*
Ca(OH)2
mg/1
185
185
185
185
185
185
370
370
740
0
555
555
185
185
185
185
370
370
333
333
333
333
185
185
185
185
444
444
333
333
333
333
rolyte BOD
mg/1 mg/1
355
240
0.5 160
0.5
160
0.5 160
0.5
0.5
365
165
130
335
120
0.2 145
0.2
180
160
0.2 130
0.2
0.2 150
0.2
170
170
COD
mg/1
758
557
448
390
378
454
393
417
417
431
370
463
400
393
526
294
424
431
470
232
624
371
262
324
354
300
308
288
254
262
314
314
254
301
331
300
331
292
PO,
mg/1
29.7
25.0
5.86
5.42
4.05
2.68
3.26
3.92
2.93
2.61
0.39
32.0
3.14
2.52
25.0
21.2
6.54
5.50
4.83
5.21
23.0
19.1
0.65
1.17
1.24
1.17
1.30
1.04
1.83
1.30
1.30
1.30
0.52
0.78
1.17
1.30
1.17
1.40
*Raw =« Raw Sewage Sample
Filter = Raw sewage sample filtered; no chemical addition.
Number of Tests = Raw sewage sample, with chemical additions and sludge
recycle as indicated.
27
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biological up-take phenomenon of the complete-mix aeration process. The
results also indicated that a higher lime addition, sufficient to raise
the pH to the range of 10, would not provide a significant enough P04
reduction in relation to the amount of chemical required.
The data further indicated that a pH increase in the range of 10.9 to
11.6 would have a striking effect on the phosphate residual, but at an
extremely high cost in chemical addition. A considerable aid to the
removal of the phosphorus by chemical precipitation was the recycling of
the primary sludge. The data in Table 5. indicates this effect. From
these results, and from a summary of the manufacturer's experience, the
sludge recirculation ratio was chosen at 50%, with the chemical addition
directly to the recycled sludge before it was to be mixed with the raw
sewage.
The net result of the primary operation was anticipated to be a phosphorus
reduction of 85%, and a BOD removal of 60%. This latter reduction was
judged to have a significant effect upon the complete-mix process, in that
the sizing of the aerators could be considerably less than with conventional
primary treatment.
BASIS OF DESIGN
On completion of the bench scale testing, and with the processes having
been selected, detailed design of this advanced waste treatment facility
was commenced in the latter part of 1968. Due to the fact that in 1968
the type of design contemplated had not been previously developed as one
total package, it was anticipated that there might be some variations
from the design basis necessary in the development of the detailed draw-
ings and specifications.
As the design developed, it was found that there were indeed a number of
variations required, some occasioned by the availability of equipment,
some due to the limitations of the then available control systems, and
certain modifications by reason of political considerations involved
in the future growth of the area that developed during the design stage.
As with the 1965 project, described in an earlier section of this study,
the 1970 project required the development of a detailed basis of design,
and submission of that basis to Federal and State regulatory agencies for
their approval. The detailed basis of design and the component calcula-
tions for the 1970 AWT facility are included in this study as Appendix A.
This data included in Appendix A is that which was submitted in early
1969 to the State and Federal regulatory agencies, and certain of these
numbers were modified during the period between the completion of design
and the initiation of construction, which spanned a period of some four-
teen months. In actual practice, additional modifications continued
during the construction period, and even now, with one year of operation
completed, there are variations being made to the total facility as the
method of operation utilized points to the necessity for such changes.
28
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As mentioned earlier in this study, it was common in the 1960s for State
regulatory agencies to publish design guidelines for sewage treatment
plants, which set limiting factors with respect to unit sizing, deten-
tion times, overflow rates, and the like. Although these sewerage
manuals were intended to be guidelines, as most often happens with
regulatory agencies, they became, in many instances, inflexible require-
ments. One of the early problems with the design of the Hatfield Township
advanced waste treatment facility was the necessity of convincing the
State regulatory agency that many of the design parameters contained in
their guidelines were not applicable to the type of treatment process to
be utilized in the new facility.
In the development of the design of this project, it was recognized that
the suburban character of this community, and other communities surrounding,
which would eventually utilize this facility for treatment of their
wastes, would require further expansion of the advanced waste treatment
facility at some future date. In consideration of this fact, the hydraulic
design capacity of 3.6 mgd (13,626 m-Yday) reflected the best estimate
of capacity required by approximately 1980. In a suburban community,
such as Hatfield Township, where there is ample growing room left, the
development of adequate waste treatment facilities becomes a continuing
process, as opposed to the more built-up and stabilized urban areas,
where total flows are not likely to vary in future years.
In the development of the basis of design, peak instantaneous rates of
flow were assumed at 200% of the average daily flow, or 7.2 mgd (27,252
m-^/day) . This is equivalent to a flow rate of 5,000 gpm (18,925 I/minute),
but the raw sewage pumping facilities and the yard piping were sized,
with the addition of a third raw sewage pump, for an ultimate peak
instantaneous flow of approximately 10,000 gpm or 14.4 mgd (54,504
m^/day). Throughout the design of the individual facilities, which made
up the total plant, wherever future expansion would be rendered partic-
ularly difficult, such as in underground piping or in building expansion,
sufficient capacity was provided to enable the next expansion, perhaps
in 1980, to be accomplished without the necessity of duplicating these
costly types of construction.
Items included in the design of the project which will not require
duplication at the next expansion stage, include the raw sewage pumping,
the chemical feed and storage, the flow equalization, and the tertiary
filtration.
The organic loadings utilized as a basis for design of this new facility
reflected the commonly used parameters in the United States of 0.17
pounds per capita per day (0.077 kg/day) in both BOD and suspended
solids. These loading rates are equivalent to 226 mg/1, but in 1969 the
average BOD was approximately 192 mg/1, and the suspended solids 178
mg/1. The higher total BOD and total suspended solids was assumed to
include a much greater use of such devices as home garbage grinders,
29
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which tend to increase significantly the total solids loading as well as
the BOD. The industrial fraction of the 3.6 mgd (13,626 cum/ day) design
flow was assumed to have a future total BOD and suspended solids loading
of 0.2 per equivalent capita per day (0.091 kg/ cap. /day) , or the equiv-
alent of approximately 264 mg/1.
The other basic parameter, that of phosphorus, is not indicated on the
basis of design in Appendix A simply because the bench scale testing
done, as well as the data available in the literature, indicated that
the effluent phosphorus for a process using lime precipitation was
essentially independent of the value in the raw waste. A normal figure
for phosphorus in raw waste would be 10 mg/1 as P , or 30 mg/1 as
The parameter for coliform bacteria does not require consideration of
raw values, but instead, requires efficient chlorination of the final
plant effluent.
P RE-TREATMENT AND RAW SEWAGE PUMPING
At the time of the construction of the 1965 project, pre- treatment of
the sewage wastes prior to raw sewage pumping, was limited to comminu-
tion of the waste. Because the collection system was constructed new in
1965, utilization of grit facilities, and the utilization of coarse
screening ahead of all unit processes, was not considered necessary.
With the 1970 project, the subject of providing coarse screening and
grit removal ahead of comminution was explored, but within the economic
limitations placed on the consulting engineer by the community, it was
felt that these desirable functions could not be considered as part of
the 1970 project, but would have to be constructed at a subsequent time.
At the time of the 1965 construction, all sewage entering the sewage
treatment plant reached the facility through a 24 inch (0.60 m) gravity
sewer terminating at what was then the main pump station, and is now
referred to as Pump Station No. 1. This station was equipped with a
single comminutor with a capacity range of 0.3 mgd to 3.5 mgd (1,136
m3/3ay to 13,248 m3/day) .
This Pump Station No. 1, the original pumping facility, was provided
with three pumps; Pump No. 1 rated at 1,300 gpm (82.03 I/sec. ) (4,914
1/min.), Pump No. 2 at 1,000 gpm (63.1 I/sec. ) (3, 785 1/min.), and Pump
No. 3 at 500 gpm (31.55 I/sec. ) (1, 890 1/min.). The maximum capability
of this original pumping station was 1,840 gpm (116 I/sec.) (6,964
1/min. ) .
The 1970 project provided for the construction of a second main pumping
station, referred to as Pump Station No. 2, with a metering chamber and
comminuting pit ahead of the pump wet well. This metering chamber was
equipped with a comminutor of the same size as was originally installed
30
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in Pump Station No. 1, and a duplicate unit was installed in Pump Sta-
tion No. 1 in what had previously been an auxiliary by-pass channel.
There therefore exist at the present time, comminutors with a total
capacity of 10.5 mgd (39,742 m^/day), and there is a space reserved in
the new metering chamber ahead of Pump Station No. 2, for the instal-
lation of a fourth comminutor of the same size, such that the total
future capacity available for comminution is 14.0 mgd (52,990 m3/day).
New raw sewage pumping facilities provided for Pump Station No. 2,
included two constant speed pumps, each with a capacity of 3,500 gpm
(220.8 I/sec.)(13,248 1/min.), with provision for the installation of a
third pump of the same size. There was a 30 inch tie-in between the wet
wells of Pump Stations No. 1 and 2 provided, so that the total effective
capacity of both sections would be available. Upon the installation of
the future third pump in Pump Station No. 2, the total available pumping
capacity, with respect to the raw sewage, will be approximately 11,040
gpm (41,786 1/min.), or sufficient to handle a flow of approximately
15.9 mgd (60,180 m3/day).
A schematic plan of Pump Stations No. 1 and 2 is shown in Figure 5.
FLOW EQUALIZATION
One of the factors which is a prime requisite for successful advanced
waste treatment is the flow equalization phase of the process.
The design of a flow equalization, or surge storage, system requires the
development of three factors. The first factor is the rate of total
daily average flow anticipated to reach the plant in any one hour or
one-half hour period throughout the 24-hour day. The second factor is
the amount and the period of time during the day when recycled water
from other plant processes will reach the influent point. In this cate-
gory would be included filter backwash waters, thickener overflow wastes,
centrifuge centrate, vacuum filter filtrate, and any other item of
reasonable proportion which would find its way back into the flow
stream. The third factor is the limiting flow factor for the most crit-
ical portion of the plant process.
In the case of the Hatfield Township advanced waste treatment facility
design, the surge storage basins were sized as shown in Section "R" of
Appendix A. The percentage of hourly flow factor was developed from a
compilation of data taken from the flow charts of the 1965 plant oper-
ation during the year 1968 and the early part of 1969. In developing
this factor for surge storage, it is most useful if historical data can
be utilized, but in the absence of historical data, one must take into
consideration unusual circumstances which might cause peaking of flows
during periods of the day because of industrial operations or other
local situations. This percentage factor is then applied to the total
31
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20
20
FUTURE'
4
WET WELL
PUMP STATION NO. 2
FLOW NOZZLE
N6" BACKWASH
WASTE PIPE
TIE-IN LINE
TO P.S. NO. I
PLANT
DRAINS
'30 TIE-IN LINE TO RS. NO. 2
,.FLOW METER
WET WELL
© Y® Y©
500GPMA 1000 6PM A 1300 GPM
RSp-J JL RSP-2 T RSP-I
PUMP STATION NO. I
BAR SCREEN
Figure 5. Schematic of Pump Station No. 1 and No. 2
32
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average daily raw sewage flow to develop the flow in gallons for each
one hour period. It is suggested that the one hour periods represent a
reasonable basis for the development of surge storage requirements,
although other periods of variation throughout the day might be util-
ized.
In the Hatfield operation, it was assumed that there would be a backwash
return from the tertiary filter system, based upon backwashing each of
the three filters four times per day. This would be the anticipated
situation at design flow capacity. In the data shown in Appendix A, no
values were assumed for the thickener overflow of the vacuum filter
filtrate. In any calculation where the surge storage facilities are to
be sized in close approximation to the surge buildup required to be
handled, all of the flows which cycle into the influent stream should be
accounted for. In the case of the Hatfield design, it was anticipated
that surge storage would be provided far in excess of the requirement,
and therefore, only the major sources of flow were calculated in the
table.
In the design of the Hatfield surge storage system, the limiting factor
in the entire process was the capacity of the tertiary mixed-media
filters. In other systems not utilizing a filter as a limiting cri-
teria, this value may be the overflow rate on a secondary clarifier, the
detention time in an aeration system, or the like.
The hourly accumulation of surge storage in gallons is then the dif-
ference between the total flow from all sources in gallons in any given
hourly period, and the limiting capacity of flow through the critical
plant process in that period. The total buildup of surge storage
required in gallons is then a cumulative summary of the hourly accumu-
lations. Where the hourly accumulation shows a negative sign, that is
the total flow through the plant is less than the limiting unit process
capacity, the buildup is assigned a zero. Where a positive accumulation
is indicated, it becomes a factor for that hourly period in the total
buildup. Reference to the Table in Appendix A for the surge storage,
indicates that at Hatfield Township, it was anticipated that the maximum
surge capacity required would occur between 1:00 and 2:00 P.M., when it
would amount to 206,400 gallons (781.2 m3).
In the actual construction of the Hatfield AWT facility, duplicate surge
storage tanks, each wj.th a capacity of 268,000 gallons (1,014 m3), were
provided. Thus, the total capacity in the main surge storage tanks is
536,000 gallons (2,029 m3). In addition to these main surge storage
facilities, the existing primary clarifiers from the 1965 project were
converted to auziliary surge storage use. These rectangular units have
a total storage capacity of 122,040 gallons (462 m3).
A schematic plan of the surge storage system is shown in Figure 6.
33
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FROM PUMP STATION
Figure 6. Surge Storage System
XINLET
Figure 7. Red Valve Mftg. Co. Pinch Valve
34
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Each of the main surge storage tanks is equipped with a propeller mixer
for the purpose of keeping solids and grit in suspension, and these pro-
peller mixers have proved to be only moderately successful. A temporary
system has been employed in one of the surge tanks, utilizing a portable
air compressor and an air line to provide more agitation to the surge
tank contents, and it has been found that this scheme is superior to the
use of the mixer alone, in that it keeps the solids in suspension far
better. During the warm summer months, the addition of the air also
helps to retard the approach of septicity.
One of the problems associated with the design of the surge storage
system was the location of a suitable control device which could operate
over a range of head conditions which would occur in the surge tanks as
excess flows were stored. The control device finally selected is known
as the "Red Valve", and a schematic representation is shown in Figure 7.
The theory of operation of the Red Valve is contained in the internal
rubber sleeve, which is compressed by a combination of liquid and air to
restrict the flow to permit a preset volume of flow through the unit.
The initial control system utilized for the Red Valve was entirely an
air pressure system, but, due to the head fluctuations in the surge
tanks, one of the valves was ruptured due to an oscillating motion set
up which could not be controlled. This was modified by the addition of
a liquid control system, in addition to the air, which has provided a
significant reduction in the tendency of the rubber sleeve to flutter.
Each of the Red Valves can be pre-set to any given flow rate, up to
2,500 gpm (9,462 1/min.).
PRIMARY TREATMENT SYSTEM
The key to the primary lime treatment system utilized at the Hatfield
Township AWT facility, is the use of recycled primary sludge to provide
seed for floe formation. A schematic plan of the flash mix system in
the chemical feed building is shown in Figure 8.
The recycled primary sludge at the rate of one-half the average daily
design flow rate, is introduced into Flash Mixer No. 2, where polymer
and lime additions are made. This mixer was designed to provide 5.5
minutes detention at a flow of one-half the design flow rate. This
mixed material then overflows into Flash Mixer No. 1, and is mixed with
the raw sewage from the surge storage tanks, which then passes over
weirs to the two primary clariflocculators. Mixer No. 1 was designed to
provide a detention of approximately 0.6 of a minute, at the design
average flow rate. The action in this smaller flash mixer should not be
less than 30 seconds.
The primary lime feed system at Hatfield Township utilizes pebble grade
35
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Figure 8. Chemical Feed Building-Primary Flash Mixer Station
-------
quick-lime (calcium oxide), which is delivered to the plant by truck,
and is unloaded pneumatically into a lime storage silo adjacent to the
chemical feed building. Lime is then transferred as needed by an auger
conveyor from the lime storage silo to the day lime storage bin inside
the chemical feed building. The bulk storage silo has a total storage
capacity of 970 cubic feet (27.5 m3), or a capacity of 29 tons (26.3
metric tons). The day storage tank has a capacity of 151 cubic feet
(4.3 m3), or 4.5 tons (4.1 metric tons).
A schematic plan of the lime feed system for the primary treatment pro-
cess is shown in Figure 9. The lime passes from the day tank, or lime
storage bin inside the chemical feed building, into a lime slaker, where
water is combined with the quick-lime to produce hydrated lime (calcium
hydroxide). The slaked lime is stored in the lime slurry tank, which is
located in the basement of the chemical feed building, until needed. It
is then pumped to a liquid lime feeder, located just adjacent to the
flash mixers on the main floor of the chemical feed building, from where
it is then fed into Rapid Mix Tank No. 2. The operation of the slaker
is automatically controlled by liquid level probes in the slurry tank.
The slurry tank is also provided with a mixer to keep the lime in suspen-
sion. The lime is metered to the flash mixer by the use of a roto-dip
volumetric feeder, and this feed is controlled by pH probes, located in
the effluent chamber of Rapid Mix Tank No. 1. The pH recorder has set
points, which automatically control the lime feed. Recently a flow-
through pH device has been inserted into the system in lieu of the pH
probes in the flash mix tank, and is found to be far more accurate and
dependable. There is also a package polymer feed station, which has
been provided in the chemical feed building, adjacent to the flash
mixers, consisting of a polymer mix tank, a mixer, and a small diaphragm
pump.
Separation of the bulk of the solids from the raw waste flow is accom-
plished in the primary clarifier-flocculators. There are two such
units, each 60'-0" in diameter, with a lO'-O" side water depth (18.29 m
diameter x 3.05 m SWD). The basic criteria for sizing a clarifier that
is used in the United States is the surface settling rate, or the rate
of total flow per day per square foot of surface area. A commonly used
parameter for a quarter of a century has been a primary surface settling
rate of between 600 to 650 gallons per square foot per day (24.4 m3/m2/day,
or 24,432 l/m2/day - 26.4 m3/m2/day, or 26,488 l/m2/day). This surface
settling rate of between 600 and 650 gal./ft.2/day has been commonly
utilized for normal primary treatment without chemical precipitation.
With chemical precipitation, primary surface settling rates have been
utilized as high as 1,000 gal./ft.2/day (40.8 m3/day sq. m).
The design of the primary clarifier-flocculators at Hatfield Township
was based upon a surface settling rate at the design flow of 3.6 mgd
(13,626 m3/day) at 637 gal./ft.2/day. This is an extremely conservative
37
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FLASH
MIXERS
Figure 9. Lime Feed System
38
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surface settling rate, and produces a detention time at the design flow
of 2.82 hours. This design has been utilized in order that sewage flows
in excess of 5.0 mgd (18,925 m3/day) could be passed through the primary
system without a serious loss of overall settling efficiency.
In the United States, is is common practice to determine the surface
settling rate on the entire surface area of both the clarifier and
flocculator sections, even though it may be technically argued that the
net clarifier section is not equal to the total surface area. The
flocculation of the mixed sewage sludge - raw waste - lime mixture is
accomplished in a circular chamber in each of the clarifiers by means
of small turbine mixers, which provide gentle agitation. When both
clarifiers are in use, the total flocculation detention is approximately
41 minutes at the design flow, and if only one unit is in service, the
flocculation detention is approximately 20 minutes at the design flow.
These two detention periods include recirculation of 50% of the design
average flow as recycled sludge.
A plan of the clariflocculator tank, including a sectional drawing, is
contained in Figure 10. The rake arms in the bottom of the clarifier-
flocculator constantly move the sludge to the center of the tank, and
the sludge is withdrawn continuously for either recycling or wasting to
the sludge thickener.
This primary treatment system was designed to remove 60% of the BOD in
the raw waste flow, or 4,230 pounds per day (1,920 kg/day).
This system also removes between 75% and 80% of the suspended solids in
the raw waste. The phosphorus removal is pH dependent. The pH is
determined by lime addition, and phosphorus removals are independent of
the raw phosphorus concentration. At low pH (9.0-9.5) approximately
2.0-2.5 mg/1 of phosphorus carries over into the secondary system. The
pH of the primary clarifier effluent will vary according to the pH level
maintained in the flocculation zone of the clarifier-flocculators, but
when this value in the flocculation zone is approximately 9.5, the pH of
the clarifier effluent is approximately 9.0 to 9.1.
SECONDARY TREATMENT SYSTEM
The design of the aeration system at Hatfield Township involved, in
1969, a radical departure from the then accepted and required standards
with relation to detention time in aeration tanks. Detention time was
the fundamental criteria, and was usually required to be a minimum of
six hours although a waste with an exceptionally high BOD loading might
require a longer detention time. The design of the Hatfield Township
aeration system was based upon the mixed-liquor suspended solids load-
ing, which provided a minimum mixed-liquor suspended solids concentration
of 1,716 mg/1. In support of the design basis utilized in the Hatfield
facility for the aeration system, the design data supplied to the regu-
latory agencies for review included a discussion of the variation from
39
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INFLUENT
PLAN
TURBINE MIXERS
1
INF PIPE
ARM
SECTION
Figure 10. Clariflocculator
40
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the regulatory manual design criteria involved in the Hatfield design.
In order that the reader may follow the method of design utilized, the
following data is quoted directly from this information which was sup-
plied.
"The design criteria of Paragraph 72.1, beginning on Page 61 of the
Sewerage Manual is aimed at producing a plant efficiency of at least 90%
when dealing with a domestic waste of average strength, and when util-
izing the conventional activated sludge process.
These design criteria generally assume a raw BOD in the range of
0.17 Lb./Capita, and a mixed liquor suspended solids concentration in
the range of 2,000 mg/1.
For a mixed liquor suspended solids concentration of 2,000 mg/1,
the BOD loading per pound of MLSS would be in the range of 0.27 to 0.28
Lb. BOD/Lb. MLSS.
In the design of any aeration system, the loading rate expressed in
Lb. BOD/Lb. MLSS is now generally recognized as the dominant criteria.
This criteria, together with the oxygen requirement expressed as Lb. O2/
Lb. BOD Applied, and the temperature, determines removal efficiencies,
and is considered the "rational" approach to the design of aeration
systems.
The aeration tank sizing is now generally recognized as being
dependent upon the quantity of mixed liquor suspended solids to be
carried in the aeration tank.
The Pennsylvania Standard is in the range of 2,000 mg/1 MLSS.
Rational design considerations are now generally at a figure of 4,000
mg/1 MLSS, and in those areas of the country where standards are not
available, this figure is utilized for design purposes.
In the rational approach, the detention time in the aeration basin
is generally not regarded as a critical factor so long as it is in
excess of 2.0 to 2.5 hours. Sewage with a largely insoluble BOD is
recognized to require a minimum detention period of 20 to 30 minutes to
effect adsorption. A completely soluble BOD is recognized to require
2.0 hours detention to effect the adsorption. Since BOD adsorption
generally proceeds a£ a slower rate than BOD stabilization, the limiting
adsorption figures provide the basis for determining minimum detention
time.
The reason that the Pennsylvania Standards utilize 6.0 hours as limiting
minimum detention period is precisely based upon the two parameters of
0.27-0.28 Lb. BOD/Lb. MLSS, and a limiting 2,000 (+/-) mg/1 MLSS. In
any set of design conditions where either or both of these parameters
are not valid, the limiting detention period of 6.0 hours likewise is
not valid.
41
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The aeration process for Hatfield Township utilizes the complete-
mix activated sludge concept. This concept, as those of other aeration
processes such as high rate activated sludge, biosorption, extended
aeration and contact stabilization, is a modification of the conven-
tional activated sludge process utilizing plug-flow aeration.
The complete-mix activated sludge system attempts to minimize the
cycle of growth of the organisms in the waste by mixing raw wastes com-
pletely with the micro-organisms in the aeration tank. This puts a more
uniform load on the aeration tank and gives a more uniform oxygen demand
with a lower demand rate than traditional activated sludge. The same
treatment results can be obtained in less time since complete mixing
dilutes the waste.
Complete-mix process designs in use today are based upon the mathe-
matical work of Professor Ross E. McKinney, University of Kansas, which
is contained in a paper, "Mathematics of Complete-Mixing Activated
Sludge", Journal of the Sanitary Engineering Division, ASCE, May 1962.
There are numerous equations presented by McKinney, but the key
equations in determining the loading, oxygen requirements and quantity
of mixed liquor suspended solids carried in a normal treatment system
are equations noted in his paper as 7f, 12a and 21.
In McKinney's analysis, there is a relationship, as previously
stated, between BOD loading, temperature, oxygen requirements, and
removal efficiencies. If one of these factors is changed during oper-
ation, the effect on the other factors can be predicted as follows:
Decrease in temperature causes decrease in removal efficiency.
Decrease in BOD applied causes increase in O2/BOD applied.
Decrease in BOD applied causes increase in removal efficiency.
Decrease in MLSS causes decrease in O2/BOD applied.
Decrease in MLSS causes decrease in removal efficiency.
In general, the design procedures evolved from the McKinney anal-
ysis utilize the desired BOD removal and the lowest expected mixed
liquor temperature for the plant to determine the loading, and then the
aeration tank sizing. The oxygen requirements are found based upon this
previously determined loading and the highest expected temperature.
This procedure results in an inherent safety factor in the design since
the design is based upon extreme conditions and the operation will be
somewhere between these extremes.
42
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From the McKinney analysis, various sources have determined design
loadings as follows:
Type of Process
Extended Aeration 0.1 Lb. BOD/Lb. MLSS
Conventional 0.3 Lb. BOD/Lb. MLSS
Complete-Mix 0.5 Lb. BOD/Lb. MLSS
Modified Aeration 1.0 Lb. BOD/Lb. MLSS
From the above, it can be seen that the loading rate for a con-
ventional activated sludge system closely approaches the Sewerage
Manual, where the figure is 0.27 to 0.28 Lb. BOD/Lb. MLSS. In a com-
plete-mix system, homogeneity is approached. As feed enters the tank,
it is instantaneously distributed throughout the entire tank. Due to
this instantaneous action, the aeration volume smooths out variations in
the feed and maximizes the effectiveness of the mixed liquor in reducing
the load. In a conventional system, more mixed liquor is required to
reduce a similar quantity of BOD. Thus, a lower loading must be employed
to get the same efficiency as a complete-mix system.
In any aerobic system, complete stabilization of the BOD will
require 1.4 to 1.8 pounds of oxygen per pound of BOD applied, depending
upon the temperature. If complete stabilization is to be effected in
the aeration basins, then the total oxygen input to the aeration basins
would have to be in the range indicated.
However, in neither a conventional activated sludge plant, nor in a
complete-mix activated sludge plant, is total stabilization a function
of the aeration process. Therefore, each pound of BOD will require some
lesser amount of oxygen than 1.4 to 1.8 pound to provide the desired
efficiency. Application of the McKinney equations, with the attendant
consideration of loading and lowest mixed liquor temperature antici-
pated, and loading and the highest temperature anticipated, generally
result in a range of 0.7 Lb. 02 per Lb. MLSS, where an efficiency of 85%
or better is desired.
The treatment process to be utilized for Hatfield Township provides
for a primary settled and precipitated sewage feed to complete-mix
activated sludge tanks, followed by settling, and with incineration of
the waste activated sludge.
With reference to the loading rate of 0.35 Lb. BOD/Lb. MLSS for the
domestic waste, this figure is actually conservative. Based upon the
McKinney analysis, a complete-mix system can be loaded at 0.5 Lb. BOD/
Lb. MLSS. In fact, the loading chosen is only slightly above the
McKinney value for conventional activated sludge.
43
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With reference to the oxygen supplied, the 0.8 Lb. O2/Lb. BOD
Applied is in the upper range of the McKinney values determined from the
application of his equations, in order to produce a plant efficiency of
at least 90%.
The aerators in the aeration basins have been selected to carry a
minimum of 2 mg/1 of dissolved oxygen in the mixed liquor at an eleva-
tion of 500 feet, and a temperature of 25° C.
The design criteria chosen have been fixed to a certain extent by
the capacity of the existing aeration basin. The resultant duplication
of units, coupled with the chemical precipitation of the raw wastewater
will result in a concentration of 1,716 mg/1 of mixed liquor suspended
solids. It would have been desirable to reduce the aeration volume to
achieve a higher MLSS concentration, but the design will allow a 100%
increase in sewage strength without affecting performance. Therefore,
even though the 3.75 hours is probably a maximum detention period, it
will be utilized to cope with possible variations in future sewage
strength."
As indicated in the above data submitted to the regulatory agency, it
would have been desirable to size the aeration basin to carry a much
higher mixed liquor suspended solids concentration, thereby reducing the
size. A decision was made, however, to construct the second aeration
basin of the same size as the existing unit, which was modified from
diffused air to mechanical aeration, and this provided the basis for the
theoretical detention time of 3.75 hours.
This detention period of 3.75 hours, which varied significantly from the
then commonly accepted minimum figure of 6 hours, caused the regulatory
agency to request substantiation of the design. In the work done by
Professor McKinney, he developed a theory that the activity in the
aeration basin, or the active microbial fraction, is an inverse function
of the sludge age, which is, in turn, a function of the mixed liquor
suspended solids divided by the loading of the aeration system. McKin-
ney 's work also developed a theoretical required detention time based on
BOD stabilization at a rate of 25 mg/1 of BOD/hour. In Table 6, which
follows, the data which was submitted to the regulatory agencies as
additional substantiation of the design, is reproduced.
The information in Table 6. indicates that the loading rate could have
been as high as 0.53 Lb. BOD/Lb. MLSS, hence the actual loading rate of
0.35 Lb. BOD/Lb. MLSS was conservative. It also indicates that the
theoretical required detention time at the design MLSS of 1,716 mg/1
would be 3.6 hours, or slightly less than the 3.7 hours provided. It
further shows that the theoretical required detention time at a MLSS
concentration of 3,500 mg/1, and a stabilization rate of the aeration
basin at a much higher MLSS concentration actually reduces the required
amount of detention time.
44
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TABLE 6. HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
AERATION TANKS @ 3.6 MGD
1. Sludge Age
Lb. MLSS
Lb. BOD/Day
2. Active Microbial Fraction
SA =• 8,050 Lb. MLSS
2,820 Lb. BOD
2.85 Days
AMF
0.35
2.85
3. Loading Rate
Permissable Range for High-Rate System Between 1 and 2 Lb. BOD/
Lb. AMF/Day At Average Range of 1.5 Lb. BOD/Lb. AMF/Day:
1.5 Lb. BOD
0.53 Lb. BOD/Lb. MLSS
(1 Lb. AMF + 1.85 Lb. AMF)
Actual Loading rate Utilized =• 0.35 Lb. BOD/Lb. MLSS
4. Theoretical Required Detention Time @ 1,176 mg/1 MLSS @ Stabilization
Rate of 25 mg/1 BOD/Hour
226 mg/1 Raw BOD x 0.40 = 90.5 mg/1 BOD to Aerator = 3 6 Hours
25 mg/1 per Hour 25 mg/1 per Hour
Actual Detention Time Provided
3.75 Hours
5. Theoretical Required Detention Time @ 3,500 mg/1 MLSS @ Stabilization
Rate of 35 mg/1 BOD/Hour
90.5 mg/1 BOD to Aerator
35 mg/1 per Hour
2.6 Hours
45
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In the construction of the 1965 project, the activated sludge tanks were
supplied with diffused air from blowers. In the 1970 project, it was
determined that mechanical mixing was required in order to achieve the
complete-mix result.
It was determined that the utilization of combination aerators, pro-
viding mechanical mixing at the surface, and surface transfer of oxygen
as well as sparged air diffusion at the lower level of the tank, would
be desirable. Inasmuch as the three existing blowers had adequate
capacity to supply this air to be introduced at the bottom of the tank,
it was felt that these combination aerators were the best choice for the
introduction of oxygen into the aeration tanks. The calculations for
the amount of air required are contained in Appendix A, and it was
decided to provide 100% of the total air requirements in each aeration
basin.
A schematic plan of an aeration basin is contained in Figure 11.
The utilization of the combination aerators is far more flexible than
fixed mechanical surface aerators, or diffused air, by themselves. As
it subsequently occurred at Hatfield Township, additional requirements
were placed on nitrification, and even more stringent future additional
requirements are anticipated. Since good nitrification in an aeration
basin is, in large part, a function of the oxygen transfer, the ability
to provide excess amounts of oxygen is greatly to be desired. Also,
during colder weather, with the solubility of the oxygen in the waste at
a higher level, it is possible to supply ample oxygen to the aeration
basins by the use of the surface mixing alone, and therefore save in
power costs the air that would normally be supplied from the blowers.
This ability to vary the air input to an aeration basin is particularly
of value in those situations where flows increase gradually over a
period of time, thus requiring more air. It is possible with combi-
nation units to meet these increasing oxygen needs and at the same time
conserve energy by regulating blowers to only supply the necessary air.
The second, and perhaps the most important component of the total secon-
dary treatment system, are the final settling tanks. These final
settling tanks serve a dual function of separating the solids fraction
from the mixed liquor flow, and providing for a rapid return of this
solids fraction as return activated sludge before it has an opportunity
to deteriorate. This ability to return activated sludge to the aeration
system in a relatively short period ot time, while it still maintains
its activity, is fundamental to the operation of any secondary treatment
system.
Therefore, the design of final, or secondary, clarifiers requires atten-
tion to surface settling rates and detention times, but it also requires
particular attention to the method of sludge return, which can be pro-
vided in the unit itself.
46
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W.L.
IMPELLER
,-INFLUENT
SUBMERGED
TURBINE
SPARGE RING
-AIR MAIN
EFFLUENT
Figure 11. Aeration Tank
47
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In Figure 12, a sectional plan of the final settling tanks used in
Hatfield Township, is shown. As in a conventional settling tank, a rake
mechanism is provided to channel sludge to a center hopper. In a rapid
sludge removal clarifier, however, there are up-take pipes attached to
the rake arms which discharge into a center well and column for rapid
removal of the sludge as it settles over the entire tank bottom. The
sludge withdrawal valves are located in this center section, and are
provided with rings of uniform height, which can be removed so that the
flow out of these pipes can be determined within relatively close limits
by the variation in the height of the overflow pipe and the water level
in the remaining portion of the tank.
This clarifier operates on a siphon principle. All sludges are raked
toward the center of the unit with the inert, denser, sludge eventually
being directly pumped from the sludge pocket. The sludge level in the
sludge box is maintained at a lower water level than that of the clari-
fier by pumping. This creates a siphon effect which draws the lighter
more volatile sludge up the withdrawal pipes mounted on the rake arms.
This sludge is then recycled to maintain the reactor.
The maximum surface settling rate generally considered for a secondary
clarifier unit, based upon regulatory agency criteria, is 1,000 gal/
ft^/day (40.69 m3/m2/day). Some designers have taken the rational
approach that, with rapid sludge removal facilities, settling rates may
be in the range of 1,400 gal/ft2/day (56.97 m3/m2/day). The Hatfield
Township design is based upon a surface settling rate of 758 gal/ft^/day
(30.88 m3/m2/day). The total detention time when both secondary clari-
fiers are in use, at the design flow, is 2.85 hours.
Based upon rational design criteria, the secondary treatment system is
capable of operating at a level much higher than the design flow of 3.6
mgd (13,626 m^/day). If the aeration system is operated at a mixed
liquor suspended solids content in excess of 3,500 mg/1, and if it is
assumed that the stabilization of 35 mg/1/BOD/hour is reasonable, then
the aeration basins, theoretically, have a capacity, without considera-
tion of any nitrification, of slightly in excess of 5.0 mgd (18,925
m3/day). If a surface settling rate of 1,400 gal/ft2/day is considered
as rational for a secondary clarifier system, the secondary clarifiers
then have a capacity to absorb a flow approximating 6.5 mgd (24,602
m3/day). Thus, the limiting capacity of the secondary treatment system
would appear to be approximately 5.0 mgd. With a similar rational
maximum flow for the primary system, the plant process, including
primary chemical precipitation, aeration, and secondary settling, can
function at a much higher level than the average design capacity. This,
however, is dependent upon the flow equalization eliminating peaks from
the primary and secondary units of these high flow values.
48
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AFFLUENT
-P-
24 C.I.P
SECTION
SLUDGE WITHDRAWAL
Figure 12. Secondary Clarifier
-------
TERTIARY TREATMENT SYSTEM
At the time of the initial conceptual planning for the 1970 project, the
original plan provided for a tertiary treatment system consisting solely
of an alum feed system and the tertiary mixed-media filters. It was
anticipated that an alum feed of approximately 40 mg/1, directly ahead
of the filters, would be sufficient to polish the secondary effluent and
that the utilization of the tertiary filtration system would reduce the
phosphorus residual to an acceptable level.
During the development of the design drawings, however, intensive discus-
sions with research personnel from the manufacturer who ultimately
furnished the equipment, as well as other recognized experts on advanced
waste treatment, led to the conclusion that a significantly higher alum
feed might be required, and if that were the case, the tertiary filtra-
tion step would have to be preceded by a flash mix-flocculation-settling
process. As the actual operation has shown, this was a correct assump-
tion because the current alum feed is in excess of 120 mg/1. Operation
of the system without the tertiary flocculation-settling step does not
produce the quality of effluent attainable as when these units are
utilized.
The design of the tertiary system at Hatfield Township includes dupli-
cate flash mixing chambers, duplicate flocculation chambers, and
duplicate tube settler units. The flash mixing chamber provides for a
detention of 4.33 minutes at one-half the average design flow, or 2.17
minutes at average design flow. The capacity of each flash mix unit is
722 cubic feet (20.4 m^) . Each rectangular flocculation unit has a
volume of 3,744 cubic feet (106 m^), and the detention time in each
flocculation unit is 22.5 minutes at one-half the design flow, or 11.2
minutes at the total average design flow. A sectional plan of the rapid
mix-flocculator tank is shown in Figure 13.
As indicated previously, in 1969, consideration of tube settlers for
tertiary clarification was a new concept, and even today, the use of
tube settling clarifiers throughout the United States is not widely
implemented.
The theory behind the development of tube settling modules is an exten-
sion of the long recognized principals of sedimentation, as developed
early in this century with respect to the efficiency of shallow depth
sedimentation. Instead of using wide, shallow trays to promote better
settling characteristics, small dimension tubes have been utilized
instead. These tubes offer optimum hydraulic conditions for sedimen-
tation, with a large wetted perimeter relative to the wetted area.
These tubes develop laminar flow conditions, and when inclined at a 60°
angle, the tubes develop a solids build-up which reaches a certain level
in the tube and then falls back down along the length of the tube,
counter-current to the upward flow of the waste. In theory, these tubes
50
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rMIXER
A
FLASH
AiliX
-REDWOOD BAFFLE
NALUM. FEED
NNFLUENT
DRY
WELL
^POLYMER FEED
. n
ICE
XL
~nr
SECTION
WATER LEVEL •
FLOCCULATOR
PADDLES
J V
^ ^
^ F1
-cr
Figure 13. Rapid Mix-Flocculator Tank
EFFLUENT
CHANNEL
ILL
_LL
TT"
n
-------
are essentially self-cleaning in nature, providing a continuous sludge
deposit is directed towards the bottom of the clarifier.
These tube modules are generally composed of bundles of 2" x 2" chan-
nels, lying at a 60° angle on alternate facings. These modules are
normally constructed of Polyvinyl Chloride sheets, with Alkylbenzene
Sulfonate channels, solvent welded together. They normally are provided
in a bundle 10' in length, 30" in width, and 20" in depth (3.05 m x 0.76
m wide x 0.5 m deep). The 2" x 2" tube is equivalent to approximately
5.1 cm x 5.1 cm. A module bundle covering the standard size provides
300 ft2 of tube area (27.9 m2), but covers a water surface area of only
25 ft2 (2.3 m2).
The installation in Hatfield Township provides 880 ft2 (81.8 m2) of
water surface area, under which tubes are located. This is equivalent
to 10.560 ft2 (981.6 m2), which produces a surface settling rate equiv-
alent to 170 gal/ft2/day (0.48 m3/m2/day). These units have the ability
to absorb flows of approximately 14.4 mgd (54,504 m3/day) and still not
exceed a surface settling rate of 1,000 gal/ft2/day. In Figure 14, a
representation of a standard inclined tube module bundle is shown.
The configuration of a tube settler, or a tube clarifier, varies from
that of a normal settling unit in that it is relatively shallow in depth
from the bottom of the clarifier to the bottom of the tubes, and there
is a 2' depth of water over the top of the tubes to the overflow weir
elevation. A sectional plan of the tube type settler is in Figure 14.
In the operation at Hatfield Township, it has been found that although
the tubes are essentially self-cleansing, with continuous solids depos-
ition to the bottom of the tank, periodically it is desirable to hose
down the tubes from the top to completely clean any accumulated material
which has not sluffed-off.
The chemical feed system in this tertiary portion of the treatment
process involves mixing alum in an alum storage tank with water, and
then discharge to liquid alum feeders for proportionong to the tertiary
flash mixers. As indicated earlier, the original design envisioned an
alum feed in the range of 40 mg/1, hence the utilization of an alum
storage tank with batch bag mixing. In actual practice, the alum feed
at times has been in excess of 140 mg/1, primarily to adjust the pH of
the secondary effluent before the coagulant begins to work properly.
Consideration is now being given to the installation of bulk liquid alum
storage and, as an alternative, an acid feed system to control the pH.
The final portion of the tertiary treatment process is the three mixed-
media filters. Effluent from the tertiary tube clarifiers is pumped
through these pressure filters. Each filter is 28' long by 10' in
diameter (8.53 m long x 3 m diameter). Each filter has an effective
52
-------
Ln
LO
SECTION
TUBE-TYPE CLARIFtER
DETAIL
TUBE MODULE
Figure 14. Inclined Tube Settler System Arrangement
-------
surface area of 287 ft2 (26.7 m2), and the total available filter
surface area provided is 861 ft2 (80.1 m2).
At the design flow rate of 3.6 mgd (13,626 m^/day) the filtration rate
is 2.9 gal/min/ft2. Filters of this type have been successfully operated
at a level of 7.5 gpm/ft2, so that these filters have a maximum effective
capacity of 9.28 mgd (35,125 m3/day).
These pressure filters are known as mixed-media filters, because the
filtering medium consists of anthracite, sand, and garnet, above a
gravel support, with the filtering materials being graded inversely to a
normal sand filter. The larger, more porous materials are at the top
surface, and the gradation of the materials decreases with increasing
depth. The structuring of these materials is maintained due to the
specific gravity of each material. Each pressure filter is equipped
with a surface washing system, and the total backwash and surface wash
flow rate is just slightly in excess of 15 gpm/ft^.
Three of these units have been installed, and provision has been made
for the installation of a fourth unit. Although these units may be
operated at levels as high as 7.5 gpm/ft^ of filter area, the more
common practice is to utilize a maximum filtering rate of 5 gpm/ft2.
This means that the effective capacity of these units is approximately
6.2 mgd (23,429 m^/day). A graphic representation of a pressure filter
is contained in Figure 15.
The filter effluent proceeds to the backwash storage and chlorine contact
system. In the design of the 1970 project, it developed that the exist-
ing secondary clarifiers from the 1965 project had sufficient capacity
to store required volumes of backwash water, hence, these units were
modified by removal of the secondary clarifier mechanisms, and were
provided with chlorine solution feed lines. The flows enter these
backwash storage tanks and then overflow to the chlorine contact tank,
which was a part of the 1965 construction. At the time of the 1970
construction, the criteria for chlorine addition was an effluent resid-
ual of 0.3 mg/1, or greater. This has since been revised to a maximum
of 0.1 mg/1, and requires more precise chlorine feed control. The
backwash and chlorine contact system is diagrammed in Figure 16.
A visitor to the Hatfield Township facility can visually see the effect
of the entire treatment process by observing the backwash storage tanks
and the chlorine contact tank. It is possible, under normal operations,
to clearly see an object, such as a coin, on the bottom, through ten
feet of effluent water. This, of course, does not provide any clue as
to the efficiency of the total process in removing nutrients, but it
does demonstrate strikingly the ability of the process to remove solid
material, and hence, insoluble BOD.
As indicated in the discussion of each portion of the treatment process
54
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8 INFLUENT
VALVE
3 SURFACE
WASH
VALVE
OOOO/OO 00 o OO O OO O//00 O
O O O Oil O O O O O O O O OO\\O
Surface wash Arm
With TJ End Caps
Various Grades
of Grovel
I ' I
-------
FINAL EFFLUENT DISCHARGE
CHLORINE
CONTACT
NO.
TANK
i
'U-tXH-.-HXj-tJ
FILTER EFFLUENT-
Figure 16. Backwash and Chlorine Tank
56
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there is excess capacity available, above the design average flow of 3.6
mgd, and it is theoretically practical to load this entire treatment
plant with flows in the range of 5.0 mgd (18,925 m^/day) and still meet
the same effluent characteristics as are now being produced. No matter
how sound a design is, the effluent entering the receiving stream is the
result of essentially the operation of the system, and the operation of
the system is subject to human failures. In later chapters there will
be a detailed presentation of the mode of operation and actual operating
data during the last year. These operating data will show, on occasion,
wide variations in effluent characteristics, some occasioned by the
requirements of the Federal Demonstration Grant, but many others occa-
sioned by the type of operation provided, and by the type of.laboratory
control exercised over the operation.
57
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SECTION V
OPERATIONAL PROGRAMS
STAFFING
The design of a modern water pollution control facility must presuppose
competent personnel, capable of operating and maintaining the highly
sophisticated facilities and processes in an efficient, economic manner.
The 1965 plant was operated by a crew of five or six people, as seen in
Figure 17, operating on a 5-1/2 day per week basis. The greatest empha-
sis was placed upon maintenance of building and grounds; a formal pre-
ventive maintenance program for operational equipment was not instituted
until the construction of the new advanced waste treatment facility.
The operations personnel then, as now, had the responsibility of the
plant and the collection system. On a daily basis, one or two people
would visit the two metering pits which monitor the flow rates from an
adjoining community. They also visited the five outlying pump stations,
which provide flow to the plant. These trips were used for general
housekeeping and minor repairs. Major repairs were coordinated through
the plant manager.
Plant operations consisted of maintenance of equipment and grounds, and
operation of the sludge processing and wastewater treatment equipment on
a 5-day, 16-hour operation. Saturdays were used for clean-up and check-
ing pump stations. All analytical testing was done when possible by the
plant manager. No testing was done for quality control except for test-
ing chlorine. The only tests required by the regulatory agencies were
weekly BOD5 and suspended solids.
The ultimate selection of the processes to meet the stream criteria and
the 1965 design of the facility was predicated almost exclusively on
reducing capital, chemical, and maintenance costs, since labor was of
little significance. The average wage was $3.15 an hour for six men,
plus $9,500 per year for the plant manager.
Upon completion of the new 1970 facility and the hiring of additional
personnel, the plant was "organized" by a trade union. The average wage
has now risen to $3.90 an hour and the total wages estimated in 1973 are
$217,400, exclusive of fringe benefits. The salary schedule for present
plant personnel is shown in Table 7.
The plant is presently manned on a 7-day, 24-hour basis with a minimum
of two men per shift.
58
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HATFIELJJ TOWNSHIP AUTHORITY
Figure 17. Organization Chart Original Plant
DIRECTOR OF
CHEMIST
I
LAB
TECHNICIAN
(EXECUTIVE DIRECTOR
OPERATIONS |
CHIEF OF
OPERATIONS
1
OPERATIONS
ASSISTANT I
i
SE
OPERATIONS
ASSISTANT I
OPERATIONS
ASSISTANT II
OPERATIONS
ASSISTANT II
OPERATIONS
ASSISTANT II
OPERATIONS
ASSISTANT II
OPERATIONS
ASSISTANT II
i
CRETARY | A
OPERATIONS
ASSISTANT I
OPERATIONS
ASSISTANT II
OPERATIONS
ASSISTANT II
i
DMINISTRATIVE ASSISTANT
OPERATIONS
ASSISTANT
OPERATIONS
ASSISTANT
OPERATIONS
ASSISTANT
I
II
II
Figure 18. Organizational Chart AWT Facility
59
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TABLE 7. SALARY SCHEDULES
Classification
Trainee
I
II
III
IV
V
1973
Wage
$/Hr
3.15-3.55
3.60-3.80
3.90
4.00
4.10
4.30
1974
Numb er
Personnel
3
1
8
4
2
2
Wage
$/Hr
3.85
4.10
4.20
4.30
4.40
4.60
Number
Personnel
3
0
8
3
3
1
Responsibilities include the collection system as outlined previously,
as well as the maintenance and operation of the A.W.T. facility. This
includes overseeing the operation of over 65 different pumps, 10 air
compressors, various chemical feeders, and a sludge furnace. There are
presently 22 full-time employees, including 2 secretaries, an executive
director, a chemist, a laboratory technician and 17 multiple purpose
operators. The operators are responsible for day-to-day maintenance of
all operational equipment, as well as maintenance of effluent quality.
Figure 18, on the previous page, shows present staffing.
Due to the nature of the facility, obtaining qualified personnel was a
high priority item. The original staff provided the nucleus for the
operations personnel of the A.W.T. facility. They profited by being
present during the construction phase, and exposure to the various con-
tractors' personnel. It is now a Federal Government requirement that a
new facility have at least one operator in full-time attendance during
the last half of the construction phase.
MANPOWER TRAINING
One of the major problems that has affected the United States environ-
mental effort is the lack of trained wastewater treatment plant oper-
ations personnel. Many of the plants in the U. S. are operated by semi-
skilled individuals with a high-school education and a minimum amount of
additional formal training.
Manpower development is now subsidized in the United States by the
Environmental Protection Agency, a division of the Federal Government.
The Federal agency, in turn, works with the various State agencies
charged with the training responsibility. In the State of Pennsylvania,
this has been handled by the Public Service Institute, a division of the
Pennsylvania Department of Education. The Public Service Institute has
arranged for part-time instructors and classroom facilities, and conducts
training sessions for prospective operators.
60
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The operation of wastewater treatment plants in many States now requires
that operators be certified by the States. The Pennsylvania Department
of Environmental Resources requires that each operational plant have a
Certified Operator, as well as a Certified Back-up Operator. Depending
upon a plant's size, personnel are required to have a knowledge of math-
ematics, chemistry, biology, a mechanical aptitude and the ability to
deal with the public.
Seven of the operators at the Hatfield plant are certified by the State.
They were certified after taking courses offered through the Public
Service Institute, and upon successful completion of an examination by
the State government.
Training of operations personnel was accomplished by the following
sources:
1. Manufacturers' Representatives
2. State Sponsored courses
3. Tracy Engineers, Inc. courses
4. On-the-job training
There is probably no person better qualified to instruct in the opera-
tion of a piece of equipment or a patented, proprietary process than the
manufacturer or his agent. No one else has lived through the testing
programs and seen the problems initially overcome. In addition, no one
is in a better position to keep track of other consumers and correlate
all problem areas. The vendors for the Hatfield project were all required
to spend some time training operations personnel, and the shift schedule
was often changed to provide the bulk of the operations personnel the
opportunity to learn from thise instructors.
The State of Pennsylvania funded a training program at the Hatfield
facility which was offered to the employees as well as those of nearby
facilities. The program was held from 6:00 A.M. until 9:00 A.M., twice a
week, for ten weeks. Operators were paid from 7:30 A.M., so the Author-
ity subsidized this training course. The subjects included were the
operation of the facility, equipment operation and maintenance, and in-
plant laboratory control.
The State also sponsored several additional courses at the near-by
Community College, in which personnel affiliated with the Hatfield
facility participated. These included laboratory operations, a safety
program, and elementary, intermediate and advanced wastewater treatment
plant operator courses. Several hundred hours of instruction were
received by Hatfield personnel, which led to a deeper understanding of
the theory as well as the application of plant operations.
61
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Tracy Engineers, Inc., as the consultants to the Authority, also had an
obligation to train personnel in the system that the engineers designed.
Their representatives met with plant personnel and the Authority many
times during the end of the construction phase to outline operations. In
addition, they wrote the Operations Manual for the facility, a 300 page
manual of instructions specific towards meeting the needs of the plant.
They provided an instructor to participate in the in-plant training
course.
The writing of an operations manual for a facility such as Hatfield was
a major undertaking. It had to meet newly issued Federal requirements
and was very comprehensive. A sample page, Figure 19, is reproduced in
this report, showing the alternate valving operations for different
operating sequences.
Tracy Engineers, Inc., also offered short courses at its home office in
Camp Hill, Pennsylvania, to further supplement operator training. A
combination of well-trained instructor-engineers and visual aids made
these courses very well received.
Management periodically holds meetings with personnel, at which time
plant problems and solutions are aired, allowing personnel to share
completely their common experiences.
PLANT START-UP
The many participants in the start-up of the A.W.T. facility included
the following:
1. The Hatfield Township Municipal Authority - Owner
2. Tracy Engineers, Inc. - Design, Supervision of Construction
3. J. E. Brenneman Company - General Construction
4. Coastal Construction Company - Electrical Contractor
5. Triangle Mechanical Company - Plumbing Contractor
6. Borden Company - Mechanical Sub-contractor
7. Major Manufacturers:
a. Dorr-Oliver - Primary-Secondary System
b. Neptune-Microfloc - Tertiary System
c. Allis-Chalmers - Pumps
d. BIF Corporation - Chemical Feed System
e. Fischer & Porter - Flow Control System
62
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BAR SCREEN
SLIDE GATE
SLUICE VALVE
0-OPEN
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PUMP STATION NO. I
Figure 19. Typical Operations Manual Page
63
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The coordination of all these organizations and their representatives
was the responsibility of the engineer. At the same time the new plant
was being started up, the old plant had to be maintained in operation;
no by-passing could take place, and certain units of operation had to be
converted.
The Hatfield Township Municipal Authority, during the time of start-up,
was undergoing problems of its own. The plant personnel were growing
from six to sixteen operators, and they all required training. A new
Executive Director had been employed, and he was familiarizing himself
with operations of the plant and the Authority. Authority personnel,
however, managed to provide the contractors and manufacturers with
complete cooperation, and as a result, the startup only spanned Sep-
tember 1972 through January 1973. During this time, the contractor had
to place the new aeration tank and secondary clarifier system in line,
prior to converting the old ones. Since the aerator head box receives
its flow from the primaries, these had to be serviceable also. The two
wet wells had to be joined, which in itself was an interesting task,
since at least one had to remain in service. In addition, the old
secondary clarifiers had to be converted from secondaries to chlorine
contact units.
The only by-passing possible was the primary system, or an individual
duplicate unit. The methods used to meet these objectives were as
follows:
1. Tying Together Wet Wells
Early one morning, the source of flow was shut off to the
plant and the flow stored in the collection system. Plant
personnel pumped down Pump Station No. 1 wet well, and con-
tractor's personnel erected a sand bagged wall within the wet
well. Flow was then allowed to re-enter the wet well, except
for the isolated section. The contractor proceeded to cut a
hole into the isolated wet well section and install a 30"
•(0.762 m) by-pass line with a valve. The process was reversed
to remove the sand bags.
2. Tying In New Aeration Tank
In order to tie in the aeration tanks, the contractor ran a
temporary line from the new aeration tanks to the old secon-
dary clarifiers. This allowed him time to convert the old
aeration tank from diffused aeration to a combination mech-
anical aeration system. The converted unit was then tied in
to the new secondary clarifiers, and the plant was "in line".
Upon completion of the conversion, both tanks were connected
and the flows were transmitted to the new secondary clarifiers
and then on to the tertiary system.
64
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The existing secondary clarifiers were relatively easily converted to
chlorine contact tanks and backwash tanks, although the secondary eff-
luent had to be by-passed to the existing chlorine contact tank at the
time.
No serious problems were encountered by the contractors during the
start-up. Manufacturers' representatives were extremely cooperative,
and the plant personnel were anxious to learn. Upon completion of the
tie-ins of the major equipment and the de-bugging of the equipment, the
plant operations personnel assumed responsibility for the equipment, the
manufacturers' personnel provided brief training programs, but experi-
ence became the major teacher. The results of this experience, however,
depended upon a well equipped, completely staffed laboratory.
LABORATORY REQUIREMENTS
Laboratory facilities, when constructed in the past, were designed to
meet the minimum needs of the regulatory agencies. These requirements
were often based upon the size of the plant, smaller facilities requir-
ing less analysis, since it was assumed their effluent had less of an
environmental impact than larger plants.
The State of Pennsylvania requires a minimal amount of analysis, and
these were, at one time, limited to BOD^, Suspended Solids, Settleable
Solids, Dissolved Oxygen, MBAS and Residual Chlorine. The number and
types of tests depended upon the size and type of plant. Now, in some
cases, Ammonia-Nitrogen and Total Soluble Phosphorus are also required,
but there is no stipulation as to how these analyses are to be run.
Laboratory analysis serves three general purposes:
1. It provides the operator with information on current plant
operations.
2. It provides a record of data which is useful in future design.
3. It provides information to regulatory agencies.
Historically, the third purpose has received the greatest emphasis.
Plant operators of smaller plants have, in the past, not usually re-
ceived the training .to accurately run analyses. Since these analyses
were performed by people with limited training, or inferior procedures
were used, the historical data was often questionable, and plants were
designed using accepted national norms.
There are five basic steps involved in the correct use of a laboratory.
These include:
1. Sample collection
65
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2. Standard analysis
3. Recording and interpretation
4. Application to process
5. Report preparation
Two types of samples are generally collected at sewage treatment plants;
grab samples and composite samples. Grab samples are not representative
of average flows and are not normally used at the Hatfield facility.
They are used when an operator suspects an industrial load, or during
the daily operations for calibrating pH probes, checking SVI, and mon-
itoring residual chlorine.
Automatic composite sampling is used throughout the Hatfield Township
Municipal Authority advanced waste treatment facility. Samples are
taken of the raw wastewater, as well as the effluents from the surge
storage, primary clariflocculation, secondary clarification, tertiary
filtered, and final effluent. The sampler gathers a 1-gallon (3.785 1)
sample over a 24-hour period in a refrigerated sampler.
Composite samples are gathered daily and brought to the laboratory in
the morning, where they are stored in a refrigerator prior to analysis.
The analyses performed at the Hatfield Township facility are as follows:
1. Biological Oxygen Demand, Five Day
2. Chemical Oxygen Demand, Bichromate
3. Nitrate Nitrogen
4. Nitrite Nitrogen
5. Ammonia Nitrogen
6. Total Kjeldahl Nitrogen
7. Total Phosphorus
8. Total Soluble Phosphorus
9. Total Solids
10. Total Volatile Solids
11. Total Suspended Solids
66
-------
12. Volatile Solids
13. Fecal Coliform Organisms
14. Residual Chlorine
15. pH
16. Dissolved Oxygen
17. SVI (Sludge Volume Index)
18. Calcium
19. Alkalinity
20. Slaking Test
21. Jar Tests
All analyses are run in accordance with the 13th Edition of Standard
Methods for the Examination of Water and Wastewater, 1971, or according
to the Methods for Chemical Analysis for Water and Waste, 1971, pub-
lished by the United States Environmental Protection Agency. This
laboratory operation has proved itself to be a major item of expense to
the Authority. The analyses require fairly sophisticated equipment not
previously found in many sewage treatment plants. These tests are
performed by a graduate chemist with the ability to both perform these
analyses as well as interpret the results.
There is an emphasis in the United States on the BOD^ analysis, as the
method of control of waste treatment processes. The analysis is depend-
ent upon accurate determination of dissolved oxygen, either by wet
chemical analysis or by the membrane probe method. The BOD test is
subject to toxic upset, and requires five days to complete. The advanced
waste treatment facility controls the process with COD (Chemical Oxygen
Demand) analysis. This test requires less than two hours to complete
and is less subject to errors.
The biological transformations serve as an indication of plant effic-
iency. The ammonia nitrogen may be acted upon by bacteria for con-
version to nitrates and is indicated by the following reactions:
Protein (Organic Nitrogen) + Bacteria -> NH^+ (1)
NH4+ + 1.5 02 Nitrosomanas m^- + 2H+ + H20 (2)
2N02" + 02 Nitrobacter
67
-------
Analysis of the ammonia nitrogen provides plant operations personnel
with information on the efficiency of secondary operations, as regards
nitrification capability.
The most rigid criteria that the plant must meet is that of phosphorus
removal. Phosphorus analysis in the low range is an extremely difficult
analysis to perform. The glassware must be hot acid washed with hydro-
chloric acid at least twice to prevent contamination of the sample. All
glassware must then be kept in closed drawers or plastic bags to prevent
air contamination.
At the Hatfield facility the method used for phosphorus analysis is
strong acid (nitric and sulphuric acid) digestion, followed by the stan-
nous chloride method of analysis. The digestion process converts all of
the phosphorus to the ortho form and then it is readily measurable,
utilizing the stahnous chloride method of analysis. The complete method
appears as Appendix B of the report.
The methodology must be followed with the greatest care; contamination
of the samples, or over-digestion and the loss of sample as phosphorus
pentoxide will lead to gross errors.
Solids analysis are relatively simple to perform, but also depend upon
completely following the prescribed procedures. These include utilizing
tongs to hold Gooch crucibles and evaporating dishes to prevent moisture
from the technician's hands creating a false reading.
Upon completion of the ashing for volatile analysis of the samples, pre-
cautions must be taken to prevent loss of sample due to air currents. In
some cases, a "weighing agent", such as magnesium sulphate may be added
to prevent sample loss.
Measurements of pH and dissolved oxygen are performed by operations
personnel using portable instruments. The pH and D.O. probes are stan-
dardiced at least weekly. Operations personnel also periodically run
jar tests to determine chemical dosages.
The Hatfield plant used approximately 360 tons of high calcium lime in
1973. Periodic tests are performed on size analysis of the lime, avail-
able calcium, and inerts.
Additional analyses include fecal coliform, using the membrane method.
This method is an extremely simple method.
The analyses being performed at the Hatfield facility are compatible
with those being run by Environmental Protection Agency installations,
university research centers and other advanced waste treatment instal-
lations .
68
-------
There is also an industrial waste treatment program, as well as a stream
monitoring program in effect at the Hatfield facility. The ideal method
for monitoring heavy metals, atomic adsorption, is beyond the present
capability of the Hatfield laboratory.
The data received from the laboratory is recorded and analyzed using
statistical analysis. All data is recorded and becomes a permanent
record of the plant. Interpretation of all data is performed by the
plant chemist, the Executive Director and the engineer, in order to
improve plant operations.
The testing schedule being followed at the Hatfield plant appears as
Table 8. All test work is done with the idea of improving plant pro-
cesses .
Chemical dosing, frequency of instrument maintenance, pump settings,
etc., are all dictated by the laboratory testing program results.
TABLE 8. MINIMUM ANALYSIS SCHEDULE - 1973
Tests Sun. Mon. Tues.
BOD5 X
TSS X
COD X X
P-ORTHO
P-TOTAL X X
P-SOL-0
*
P-SOL-T X
N-NH3 X
Sample
Weds. Thurs. Fri. Sat. Points
X X *
X X *
XXX *
*
XXX *
*
X X *
X *
*See Appendix D and Table D-l
(continued...)
69
-------
Table 8 (continued) MINIMUM ANALYSIS SCHEDULE - 1973
Tests
N-N02
N-N03
N-TK
TS
VS
VSS
Sample
Sun. Mon. Tues. Weds. Thurs . Fri. Sat. Points
XX A
XX A
XX A
XX A
XX A
X A
The required physical facilities of a wastewater treatment plant lab-
oratory have increased considerably with the requirements for better
effluents. The Hatfield facility laboratory layout is shown in
Figure 20. All the following items are necessities of the A.W.T.
facility:
1. TKN Apparatus
2. High Capacity, All-glass Still
3. COD Apparatus
4. Steam Bath
5. Fume Hood
6. Wide Band-Pass Spectrophotometer
7. Large Area Hot Plate
8. 6-Gang Jar Stirrer
9. Dissolved Oxygen Meter
10. Fecal Coliform Test Apparatus
70
-------
CO
Q-
0
0
o
o
IE
oo.
BOD.
INCUBATOR
DESK
OCUP SINK
CO.D, APR
SINK
STEAM
TABLE
B.O.D.5
AREA
DRYING OVEN
LAB-
STILL
SPECTROPHOTOMETE
cc
o
UJ
CC
R
Figure 20. Laboratory Layout
71
-------
11. Adequate Washing Area
12. Laboratory Refrigerator
13. BOD5 Incubator
14. Extra Glassware
15. Analytical Balance
16. Moisture Tester
17. Muffle Furnace
Laboratory operations generally are dependent upon the availability of
bench space. The provision of extra space generally results in greater
efficiency, although unused space is subject to clutter.
An adequately staffed, efficiencly operated, and well supplied labora-
tory is the mainstay of the advanced waste treatment facility. The
results produced from such a laboratory can yield a wealth of useful
data.
INDUSTRIAL WASTE
One of the external factors which affects the plant's operations is that
of the introduction of industrial wastes into the system. There are
many small industrial facilities, as well as some large ones, which
contribute to the Hatfield plant.
One of the larger facilities in the area served is that of a manufac-
turer of steel office furniture. The company utilizes an electrolytic
paint process for coating its products. The paint is kept in a water
based solution and the steel furniture acts as an electrode, allowing
the paint to deposit evenly on the surface. Unfortunately, as the paint
solution becomes contaminated with dust and metal fines, it starts to
affect the finish. At that time the paint batch must be disposed of.
Historically, the manufacturers' personnel would add the batch of used
paint to a small clarifier to which alum was added. The alum would
clarify the liquid and the "paint sludge" would be drawn off for dis-
posal on land fill. Unfortunately, the alum system periodically failed,
and the wastewater treatment plant would get hit by a "slug" of grey,
green, tan or black paint. The paint would coat the tanks and generate
a tremendous housekeeping problem. In addition, it was toxic to the
secondary system, and the plant effluent would suffer due to loss of
secondary treatment for two to three weeks.
72
-------
The one redeeming feature was that immediately after an accidental
spill, the industrial plant's management would notify the treatment
plant. Treatment personnel would prepare for clean—up and, if possible,
contain the spill. On occasions, industrial personnel were sent to
assist in clean-up operations.
In order to eliminate the periodic spills, the industry installed a
membrane type filter on its paint spray system. The process filters the
paint solution and removes all dust and metal particulate matter, allow-
ing the paint to be reused without having to waste batches periodically.
The membrane filter system cost $150,000, yet the industrial plant
personnel found that the new system could be paid off in less than nine
months. This capital expenditure was also subject to a more rapid
depreciation under existing Federal tax laws. There was some loss of
revenue to the Authority due to the reduced flow, but this was countered
by the ability of the system to handle additional flows. The system has
been in effect for over a year, and since that time there have been no
paint spills.
The other major industries in the Township include a meat packing plant,
several plating facilities, a mushroom processor, and a dairy.
The meat packer is in the process of installing a pre-treatment system,
which includes flotation skimming, sedimentation and screening in order
to remove fats and other settleable material. Nearly all of the mater-
ial recovered from the waste streams is reusable. The blood recovered
from the kill floor is dehydrated and used as an animal feed supplement,
due to its high amount of protein. The other solid material is rendered
and used as a fertilizer supplement for fields in which cattle feed is
grown.
Mushrooms in the United States are grown in beds of moist horse manure.
The harvested mushrooms are processed by washing them and sizing them.
The wash water is extremely rich in soluble BOD^ , and pieces of mush-
romms. The firm has now installed a screening device with the intention
of removing all screenings and other large particulate material.
The platers and the dairy are currently being surcharged for excessive
waste strength.
The Authority has instituted a program of surcharging contributors of
industrial wastes. This program is included in Appendix C. A surcharge
is placed upon industries, based upon the amounts of BOD5, suspended
solids, total phosphorus, ammonia-nitrogen, pH, chlorine demand and
flow. The analytical requirements to support this program are paid for
by a permit fee program.
73
-------
The objectives of the industrial waste program are to obtain an in-
ventory of all possible industrial wastes and provide plant operators
with this information in order to anticipate industrial surges and loads
having a harmful effect upon the process. The program also provides
each industry with both a recommendation as to its pre-treatment require-
ments, and an incentive to undertake, at a minimum, the requirements as
a means of reducing its waste treatment charges. In some cases, the
industry, by practicing sound pre-treatment, can also realize revenue
from byproducts which can be sold, instead of being lost to the waste
collection system.
INFILTRATION/INFLOW
Many of the sewerage systems in the United States are subject to exces-
sive inflow and infiltration. The sources of this infiltration are
generally storm water encroaching into the sanitary collection system.
The sources of this storm water vary from illegal sources, such as sump
connections and down spouts, broken sewer lines, improperly laid lat-
erals, and low lying manholes. In an advanced waste treatment facility
where costs are generally dependent upon the amount of flow treated, any
flow reduction generally is reflected by a reduction in operating costs.
Excessive infiltration is determined by the degree to which a community's
collection system meets the State's standards relating to infiltration.
In Pennsylvania, the standard is, "the infiltration should not exceed
500 gallons per inch of pipe diameter per mile per day for any section
of the system". This amounts to 4,000 gallons/day for each mile of
conventional 8" sewer line, an extremely conservative amount when one
compares the actual experience of many operational collection systems
with the theoretical values. The Hatfield Township plant has a normal
dry weather flow of 1.8 mgd, and wet weather flow of 3.2 mgd, or 1.4 mgd
in extraneous flows. The allowable rate, according to Pennsylvania
Department of Environmental Resources standards, is less than 0.2 mgd,
which indicates there is 1.2 mgd of excessive infiltration.
The elimination of infiltration is considered necessary to eliminate
hazards caused by by-passing, reduce excessive costs of wastewater
treatment, prevent damage to lines and plant, etc. The elimination of
these extraneous flows has become as great a problem for municipalities
as modern advanced waste treatment processes.
The Federal and State governments and consulting engineers are devel-
oping methods to eliminate these problem flows.
According to the United States Environmental Protection Agency, a phased
program for sewer system evaluation should be followed. Such a program
would include, but not be limited to, the following phases:
74
-------
I. Infiltration/Inflow Analysis
A. Patterned Interviews
B. Sanitary and Storm Sewer Map Study
C. System Flow Diagrams
D. Dry Vs. Wet Weather Flow Determination
E. Preliminary Field Study and Selective Flow Tests
F. Determination of Excessive or Non-Excessive
Infiltration/Inflow
G. Establish a Plan of Action, Budget and Timetable
for Execution
II. Field Investigation and Survey
A. Physical Survey and Groundwater Analysis
B. Rainfall Simulation
C. Prepare Engineering Report and Analysis
D. Preparatory Sewer Cleaning
E. Television Inspection of Preselected Sewers
F. Preparation of the Evaluation Survey Report and
Analysis
G. Preparation of the Proposed Rehabilitation Program
III. Rehabilitation
A. Sewer Repair
B. Pipe Relining
C. Sewer Replacement
D. Manhole Repair
The purpose of Phase I is to delineate the problem and determine a
series of objectives that must be reached. The results would yield a
program to reduce the problem gradually, first eliminating the major
sources of extraneous flows, and then, step by step, correcting
75
-------
smaller problems. This would produce the best results as rapidly as
possible and be the most economical. Charting these flows could show a
diagram as indicated in Figure 21.
The cost of infiltration control is extremely difficult to estimate. One
recent article indicated costs of approximately $1.08 per lineal foot of
sewer system to seal joints, repair major manhole difficiencies, and
T.V. inspect these lines. Each project, unfortunately, must be esti-
mated on its own merits. Factors to be included are:
1. Age of Collection System
2. Materials of Construction of Collection System
3. Size of Various Pipe
4. Condition of Manholes
5. Non-sanitary Sources - eg: Downspouts, Cellar Drains, etc.
The cost of an infiltration study is quite high, and a community must be
prepared to spend money to meet the State and Federal standards.
The Hatfield facility has an on-going infiltration program, which is
exemplary. The program consists of several steps, including:
1. Raising Manholes
2. Visually Inspecting All Houses for Illegal Connections
3. Television Inspection of All Sewer Lines
4. Repairing All Suspected Leaks in Manholes and Sewer Lines
The Authority has three people on a nearly full-time program to curb
infiltration. A house-to-house survey has been made of the community to
determine illegal connections. The net result was the elimination of
several illegal sump pump connections. In addition, during this survey,
dwelling units were found which had been hooked up to the collection
system and were not being charged rent. This portion of the program
more than payed for itself. At the same time, an outside contractor was
brought in by the Authority to raise manholes on an individual basis
wherever the potential for drainage of storm water was found. The
Authority has purchased a television inspection truck and a high-pres-
sure sewer cleaning truck. These vehicles are utilized from three to
five days per week to inspect and seal possible leaks in the collection
system. The net result of an effective infiltration program is to
reduce costs of operation of the facility.
76
-------
INFILTRATION/INFLOW IDENTIFICATION
(IDEALISED EXAMPLE)
(4)
(3)
<
cc
WET WEATHER FLOW
(2)
(I)
BYPASSES ''
OVERFLOWS
T
INFLOW
i
t
INFILTRATION
t
•-INFILTRATION/ INFLOW -J
1
DOMESTIC AND
INDUSTRIAL
i
TIME
(I) PEAK DOMESTIC AND INDUSTRIAL (NO INFILTRATION/INFLOW)
(2) PEAK(NONRAINFALL) DURING PERIODS OF HIGH GROUNDWATER
(3) PEAK FLOW
(4) TOTAL FLOW
SOURCE^ EPA PROPOSED
GUIDELINES
Figure 21. Infiltration/Inflow Identification
77
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SECTION VI
OPERATIONAL RESULTS
GENERAL
Previous chapters have developed the design of the Hatfield Township.AWT
facility, and have discussed in detail the basis of design and unit
sizing. The combination of the process units finally constructed, and
the varying operating procedures carried out during the Demonstration
Grant period, have provided a significant accumulation of operational
data. Some of this data would have been anticipated as a product of the
design theory, but other data has been generated which is at variance
with predictable conclusions. Additional data is still being collected.
1972 AND 1973 OPERATION
The operation of the Hatfield Township Advanced Waste Treatment Facility
varied greatly between 1972 and 1973. In 1972, the new units were under
construction, and were phased into the operating sequence throughout the
year as they became available for use, or as their use was required to
permit modifications to existing units, such as the existing aeration
tank.
By January 1973, all of the AWT units were in operation, although not
all of the chemical additions were being accomplished in accordance with
the design, and not all the units were being operated fully in the
current mode.
1972 provided an operating situation reflecting essentially secondary
treatment, but with modifications and interruptions occasioned by the
construction program. 1973 reflected AWT operation, but, until March
1973, did not include total flow equalization, nor did it include, until
late March 1973, a fully complete lime feed program.
A summary of average removal efficiencies for the year 1972, 1973 and the
Grant period are shown in Table 9. Also values for 1974 are given.
TABLE 9. AVERAGE OVERALL REMOVAL EFFICIENCIES: PERCENT
COD
BOD5
SS
Total Phosphorus
NH3-N
1972
79
77
75
14
-21
1973
54.1
86.5
93.3
83.5
48.1
April 1973-
March 1974
55.8
94.5
95.2
90.1
71.7
1974
35.5
96.3
96.0
86.4
89.4
78
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THEORETICAL COMPOSITION OF SEWAGE
Data on the composition of domestic sewage in the United States has been
compiled by a number of different sources. One such compilation depicting
norms of wastewater concentration is contained in Table 10.
TABLE 10. COMPOSITION OF DOMESTIC SEWAGE
(Source: Babbitt and Baumann, SEWERAGE AND
& Sons, Copyright 1958, p. 341)
(All Values
Constituent
Solids, Total
Suspended, Total
Dissolved, Total
BOD (5-Day, 20° C)
Dissolved Oxygen
Nitrogen, Total
Organic Nitrogen
Free Ammonia
Nitrites (N09)
Nitrates (N03>
Alkalinity. CaC03
Total Phosphorus (P)*
in Milligrams
Strong
1,000
500
500
300
0
86
35
50
0.1
0.4
200
10
SEWAGE TREATMENT,
Per Liter)
Medium
500
300
200
200
0
50
20
30
0.1
0.2
100
8
John Wiley
Weak
200
100
100
100
0
25
10
15
0
0.1
50
6
Concentration for Total Phosphorus has been assumed.
HATFIELD TOWNSHIP SEWAGE CHARACTERISTICS
A summary of raw sewage characteristics for the years 1972, 1973, 1974,
and the Grant test period are contained in Table 11.
79
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TABLE 11. SUMMARY OF RAW SEWAGE CHARACTERISTICS
(All Values in mg/1 Unless Noted)
COD
BOD5
Org-N
NHs-N
N02-N
N03-N
TKN
pH*
Total Phosphorus
Total Soluble
Phosphorus
SS
% vss
TS
% TVS
Alk.
1972
329
124
-
58
0.8
1.4
-
7.6
8.4
6.8
173
-
1,037
-
—
1973
338.7
74.2
12.3
42.6
0.14
1.23
4.92
7.7
6.6
6.0
182.0
70.9
846.8
31.2
167.5
April 1973-
March 1974
389.7
86.7
12.3
52.6
0.11
0.39
67.2
8.0
6.8
5.1
199 . 6
71.5
872.8
30.0
167.5
1974
315.2
111.9
4.6
53.1
0.15
0.02
60.1
7.8
6.2
4.8
134.3
71.7
619.2
30.1
236.2
Median Values
A comparison of these values with the average characteristic for "normal
domestic sewage", as presented in Table 10, would indicate that total
solids and ammonia-nitrogen are of strong to medium strength, while BOD 5
and suspended solids are relatively weak. The general conclusion derived
from these raw sewage characteristics is that Hatfield has a relatively
weak domestic waste, with an industrial contribution of ammonia and
dissolved solids.
The data summarized in Table 11, for the 1972 raw sewage characteristics
is derived from Table 12. Table 12 lists the average monthly character-
istics of the raw waste for 1972, and the yearly agerage.
In Table 13, the average monthly characteristics for the final effluent
are listed for 1972. Inspection of Table 13 will indicate that the
efficiency of the 1972 operation started to increase significantly in
June and July, as new units were added to the process operation.
80
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In Table 14, the average monthly raw waste characteristics for 1973 are
shown. In Table 15, the average monthly final effluent characteristics
for 1973 are shown. A review of Table 15 will indicate a substantial
improvement in the effluent quality commencing in April, after full flow
equalization and lime addition had been instituted. Table 16 and Table
17 indicate the raw and final effluent characteristics for early 1974.
Analytical data for 1973 and 1974 are contained in Appendix D.
81
-------
BOD5
COD
TS
SS
D.O.
NH3-N
N02-N
TABLE 12. RAW WASTEWATER CHARACTERISTICS
(All Values in mg/1 Unless Noted)
Hatfield Township Municipal Authority
1972 Monthly Averages
Jan.
94
163
-
142
-
29
-
0.3
4.4
9.2
3.4
7.0
7.8
13°
Feb.
97
132
610
145
-
35
0.2
0.7
2.0
2.6
0.7
2.5
7.9
7.9°
Mar.
65
92
678
110
-
39
0.2
0.7
3.4
3.8
3.3
4.1
-
-
Apr.
95
130
582
133
5.6
45
0.2
0.8
5.0
5.6
5.0
5.5
8.1
12.8°
May
128
190
—
160
-
63.1
-
0.4
-
-
-
-
-
-
June
166
208
-
418
4.3
99.5
-
1.0
7.7
11.1
3.7
5.4
6.9
15.8
July
194
383
1974
193
6.0
71
-
1.0
9.4
9.8
9.8
9.8
6.8
o 19o
Aug.
121
1008
—
212
2.3
120.5
2.9
0.6
3.4
18.5
-
-
7.6
20.3
Sept.
157
697
1339
132
-
91.4
1.7
7.8
14.3
16.3
6.6
13.1
7.8
O
Oct.
160
608
-
208
~
77
-
0.6
6.8
9.3
5.0
-
-
-
Nov.
84
109
-
166
4.9
9.8
-
1.1
2.1
2.9
-
-
7.7
9.8°
Dec.
126
226
-
55
6.9
14.2
-
1.6
2.6
3.6
-
-
7.5
6.1°
Year
Average
124
329
1037
173
5.0
58
0.7
1.4
5.6
8.4
4.7
6.8
-
13.1'
PT (2)
Ps-0 (3)
PS-T (4)
pH Units (5)
Temp C°
(1) P0 = Ortho Phosphorus as P
(2) PT = Total Phosphorus as P
(3) Pg-0 = Soluble Ortho Phosphorus as P
(4) PS-T = Soluble Total Phosphorus as P
(5) Median Values of pH Units
-------
00
CO
TABLE 13. FINAL EFFLUENT VALUES
(All Values in mg/1 Unless Noted)
Hatfield Township Municipal Authority
1972 Monthly Averages
BOD5
COD
TS
SS
VS
VSS
D.O.
NH3-N
N02-N
N03-N
PO
PT
ps-o
PS-T
pH Units*
Temp C°
Turb. Unt
Color Unt
Jan.
63
111
-
-
-
-
-
23
-
0.4
3.2
7.0
3.1
5.2
7.9
12.5
.
-
Feb.
55
95
592
-
-
-
-
28.2
0.2
0.8
2.2
2.6
0.8
2.1
-
7.9
-
-
Mar.
46
75
507
61
-
-
8.1
20.5
0.2
0.5
3.6
3.9
3.6
4.2
7.6
-
-
-
Apr.
52
125
554
85
-
-
5.3
31
0.2
0.9
3.5
4.1
2.3
3.9
-
11.5
-
-
May
35
40
-
69
-
-
-
73
-
0.2
-
-
-
-
7.2
-
40
99
June
10
35
-
23
-
-
6.9
73.5
0.08
0.6
8.4
10.1
4.4
5.1
7.0
16.2
34
118
July
17
58
404
16
-
-
6.1
69
-
0.6
6.1
6.4
5.9
6.1
7.2
22.5
13
48
Aug.
5
235
-
-
-
-
2.1
77
1.0
0.6
4.8
20.5
-
-
7.3
21.5
-
-
Sept.
13
254
795
29
-
-
-
60
0.3
0.8
13.4
-
12.6
9.0
-
-
-
-
Oct.
8
101
-
37
-
-
-
54.2
-
0.4
10.5
12.1
6.3
-
7.7
-
-
-
Nov.
6
37
-
24
-
-
7.1
21.6
-
0.9
2.1
2.9
-
-
8.6
8.6
-
-
Dec.
12
54
-
-
-
-
7.2
20
-
1.0
1.1
1.2
-
-
-
-
-
-
Year
Avg.
27
102
570
43
-
-
6.1
46
0.3
0.6
5.4
7.2
4.9
5.1
-
14.4
33
121.3
% Re-
moval
77
79
45
75
-
-
N/A
21
-
-
4
14
0
2.5
-
-
-
-
Median Values of pH Units
-------
00
TABLE 14. RAW SEWAGE CHARACTERISTICS
1973 Monthly Averages
(All Values in mg/1 Unless Noted)
Test
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P-Total
PST
S.S.
%VSS
T.S.
%TVS
Alk.
Jan.
231
248
-
47.4
-
1.3
—
-
5.1
-
101
-
502
-
-
Feb.
257
74
-
30.6
-
7.0
-
-
3.4
-
105
-
660
-
-
Mar
196
84
-
17.7
0.2
1.9
-
-
4.9
-
91.8
-
490
-
-
Apr.
195
76.8
36.2
48.2
0.06
0.08
84.4
7.1
5.1
3.24
85.0
71
379
35.9
99.6
May
284.7
101.2
5.8
39.5
0.09
0.15
41.6
7.1
7.9
7.33
106.5
46
542
26.3
122.3
June
366.1
104.7
2.8
38.5
0.46
0.17
41.3
7.35
8.1
5.9
116.0
83.7
695
37.3
157.8
July
601.2
111.0
10.3
60.7
0.1
0.07
71
7.1
7.9
6.4
232
87.1
1252.0
43.3
-
Aug. Sept. Oct. Nov.
720.8 324 407.8 223.8
65.0 94.6 51.3 72.2
3.5 -
50.7 54.9
0.09 0.06 0.17 0.08
0.04 0.29 0.15 3.0
11
7.7 8.1 8.1 8.4
6.07 12.9 6.9 3.9
6.0 6.0 5.3 3.2
116.8 372.5 246.3 342
82.4 82.2 67.4 54.5
938 542.4 1139 1630
38.8 17.8 16.6 48
240.6 196.4 166.8 162.8
Dec.
256.7
109
15.0
31
-
0.6
46
8.0
7.2
7.5
269
64
1392
17
193.8
Avg.
Jan.-
Mar .
228
135
-
31.9
0.2
3.4
-
-
4.5
-
993
-
550.7
-
-
Avg.
Apr .-
Dec.
375.6
87.3
12.3
46.2
0.12
0.51
49.2
7.7
7.3
5.99
209.6
70.9
945.5
31.2
167.5
* Median Values
NOTE: January-March operating period involved phasing in new process units.
April-December operating period of new AWTF.
-------
oo
L/l
TABLE 15. FINAL EFFLUENT VALUES
1973 Monthly Averages
(All Values in mg/1, Unless Noted)
Test
COD
BOD 5
Org-N
NH3-N
N02-N
NH3-N
TKN
pH*
P-Total
PST
S.S.
%vss
T.S.
%TVS
Alk.
Jan.
114
73
-
31.9
1.4
-
3.3
-
29
-
400
-
-
Feb.
113
21
-
47.3
-
2.8
-
20.5
-
523
-
-
Mar.
120
20
*
31.3
0.2
2.3
-
0.9
-
10.6
-
530
-
-
Apr.
78.3
2.9
27.2
52.6
0.05
0.06
79.8
7.9
0.7
0.3
7.0
62.2
535
16.5
115
May
51.7
3.0
20.0
41.2
2.0
0.32
42.4
-
0.6
0.4
10.2
69.2
525
11.8
103.9
June
223.4
4.3
1.4
18.1
2.24
1.51
19.5
7.08
0.45
0.45
11.7
74.0
715
28
124
July
280.7
6.5
1.6
30.7
1.9
0.95
37.3
5.9
0.6
-
13.9
57.4
850
23.5
130
Aug.
338.8
2.6
2.1
0.5
0.5
1.0
2.4
6.8
0.15
0.5
8.1
61.5
806
36.2
101.7
Sept.
197.8
5.8
-
0.4
1.3
0.6
6.7
-
-
4.7
78.4
856
11.7
132.6
Oct.
109.6
2.0
-
5.6
1.1
1.1
-
0.2
0.3
16.4
43.5
891
22.0
165.6
Nov.
97.6
3.1
-
4.0
0.05
12.8
7.3
0.3
0.32
4.9
46.6
800
24.0
181.9
Dec.
143.0
16
0.7
1.7
0.1
2.4
7.7
0.1
0.1
11.0
55.0
735
12.0
132.1
Avg.
Jan.-
Mar .
115
38.3
-
36.8
0.2
1.9
-
2.3
-
20
-
486
-
-
Avg.
Apr.-
Dec.
169
5.1
8.8
17.2
1.14
2.05
28.1
7.05
0.68
0.39
9.76*
51.2 *
746 *
20.6 *
120.6
* Median Value
NOTE: January-March operating period involved phasing in new process units.
April-December operating period of new AWTF.
-------
TABLE 16. RAW SEWAGE CHARACTERISTICS
1974 Monthly Averages
(All Values in mg/1, Unless Noted)
Test
Jan.
Feb.
Mar.
Apr.
June Jul\
AUE
Sept. Oct.
Nov.
Dec.
Year
COD
BOD 5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P-Total
PST
S.S.
%VSS
TS
%TVS
Alk.
81.1
-
44.1
-
-
-
-
2.9
2.3
58.6
76.1
_
_
-
99.7
-
82
-
-
-
8.1
4.2
0.47
235.2
70.1
676.2
28.2
-
432
73.7
-
89.3
0.06
0.01
121.3
8.0
8.6
4.2
215.3
73.2
632.9
24.2
-
136
110.9
3.9
111.9
0.11
0.02
115.8
7.8
4.8
4.0
137.4
59.9
431
15.5
129.6
136.3
102.7
6.4
31.3
0.23
0.04
58
7.5
5.4
4.8
148.9
59.7
730
19.9
249.3
388.8
138.1
7.3
96.3
0.12
0.02
102.5
7.4
4.8
4.8
128.8
66.2
958
23.9
291.3
384
144.7
8.0
80
0.15
0.02
88
7.5
6.8
6.7
168.6
87.2
864
10.1
205
138.7
2.6
24.8
0.30
0.02
25
7.7
9.6
(9.8)
-
75.1
149.5
12.5
355
578.6
145.4
2.7
22.14
-
0.03
24.2
7.9
7.3
6.5
-
-
-
37.3
-
140.2
2.6
25.4
-
-
28.0
7.8
5.8
-
87
-
-
-
-
_
99.
3.
18.
0.
0.
21.
-
7.
-
107.
-
954
50.
-
8
7
9
15
022
9
0
1
9
150.7
67.5
4.4
11.0
0.14
0.02
15.4
-
7.1
-
56.5
77.9
177.5
78.2
186.7
315.2
111.9
4.6
53.1
0.15
0.022
60.1
7.8
6.2
4.8
134.3
71.7
619.2
30.1
236.2
Median Values
-------
TABLE 17. FINAL EFFLUENT VALUES
1974 Monthly Averages
(All Values in mg/1, Unless Noted)
Test
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P-Total
PST
S.S.
%VSS
TS
%TVS
Alk.
Jan.
_
3.0
-
1.2
-
-
-
7.1
0.5
0.01
8.4
68.1
-
-
-
Feb.
_
3.8
-
10.1
-
-
-
7.7
0.7
0.13
11.1
54.9
-
11.0
-
Mar.
181.3
5.1
40.7
12.7
0.1
0.2
14.6
7.5
0.71
0.7
7.0
40.3
702.7
15
180
Apr.
166.5
2.4
4.0
17.0
0.14
0.04
21.1
7.4
0.70
0.6
6.3
42.4
559
17.4
116.1
May
220.4
4.6
3.2
7.7
0.43
0.19
10.9
7.3
0.9
0.47
3.2
54
710
15.9
123.9
June
435
2.3
3.4
2.1
0.63
0.07
5.7
6.7
0.8
0.70
1.8
60.2
771
23.9
-
July
368
2.1
28
6.0
0.39
0.06
8.6
6.3
1.5
1.3
2.6
55.9
808
16.0
50
Aug.
151.5
5.6
1.4
2.6
0.70
0.11
2.5
6.1
1.2
1.05
1.9
55.7
788
50.8
-
Sept. Oct.
_
6.5
1.3
0.5
0.26
0.11
1.5
7.3
1.14
0.91
2.8
52.4
344
36.6
218.5
3.8
-
0.83
-
-
1.5
7.0
0.69
-
2.87
-
-
-
-
Nov.
16
4.6
0.6
1.09
1.93
0.28
1.6
-
0.85
-
4.2
-
802
58.4
-
Dec.
345.6
1.3
40.7
4.0
0.50
Avg.
1974
235.5
3.8
9.3
5.5
0.51
0.121 o.ll
5.3
-
0.65
0.60
3.5
63.8
331.5
81.3
164
7.3
7.1
0.86
0.65
4.64
55.8
646.2
32.6
142.1
Median Value
-------
WASTEWATER VOLUMES PROCESSED
The average plant influent flow rates for 1972, 1973 and 1974 were 1.352,
2.036 and 1.741 MGD (5.117, 7.706 and 5.589 x 103 cu m/day) respectively,
as summarized in Table 18, below, and as shown in detail in Tables 19,
20 and 21.
TABLE 18. SUMMARY OF PLANT INFLUENT FLOWS
All Values in Million Gallons*
April '73-
1972 1973 1974 March '
Total Flow 510.780 744.490 637.650 736.790
Average Daily Flow 1.352 2.036 1.741 2.004
Daily Maximum 5.880 8.000 6.280 8.000
Daily Minimum 0.390 0.640 0.500 0.500
* Million Gallons x 3785 = cubic meters
** Extracted From Tables 20 and 21
The plant flows, however, do not take into consideration the volume of
liquid recycled through a facility from sources such as thickener over-
flow, vacuum filter filtrate, incinerator scrubber water and backwash
water from the tertiary filters. Recycle data for a typical month,
March 1973, is indicated in Table 22. The amount of liquid recycled,
as well as the strength of that liquid, can result in a serious over-
loading of a treatment facility.
Total flow for the month of March 1973 was 69.04 MG (261.32 x 106 cu m),
or 2.23 MGD (8.44 x 103 cu m/day). The connected population to the facil-
ity in that month was approximately 5,734 equivalent dwelling units, pro-
portional to a population of 20•069, (EDU x 3.5 capita/EDU). With an
average domestic water consumption in the area of 100 Gal/Capita/Day
(0.38 cu m/Day/Dapita), this accounts for 2.01 MGD (7.61 x 103 cu m/Day)
with the unaccounted flows due to infiltration and/or inflow in the
sanitary sewerage collection system, as well as illegally connected sump
pumps.
The extra hydraulic load created by infiltration/inflow has been recognized
by regulatory agencies and Federal guidelines call for applicants for
public funds to either eliminate these extraneous flows or design for them.
Likewise, designers must provide for in-plant recycle loads which can equal
a large percentage of raw sewage loads.
-------
TABLE 19. SUMMARY OF INFLUENT PLANT FLOWS
Hatfield Township Municipal Authority
1972
Month - MG
January
February
March
April
May
June
July
August
September
October
November
December
Total
32,02
40.87
41.59
51.33
70.54
50.04
35.77
23.83
22.17
27.74
54.64
60.24
Average
1.30
1.41
1.34
1.66
2.52
1.67
1.15
0.77
0.74
0.90
0.82
1.94
Daily - MGD
Maximum
1.78
1.82
1.64
5.88
4.40
3.67
2.20
1.00
0.90
1.86
3.50
3.66
Minimum
1.67
0.91
0.81
0.59
0.39
0.78
0.63
0.62
0.60
0.75
0.88
1.25
1972 Total Flow:
Average Daily:
Maximum Daily:
Minimum Daily:
510,780,000 Gallons (1,933,302 cu m)
1,352,000 GPD (5,117 cu m/Day)
5,880,000 GPD (15,553 cu m/Day)
390,000 GPD (1,476 cu m/Day)
89
-------
TABLE 20. SUMMARY OF INFLUENT PLANT FLOWS
Hatfield Township Municipal Authority
1973
Month - MG
January
February
March
April
May
June
July
August
September
October
November
December
Total
52.89
61.32
69.04
99.00
65.71
65.71
57.09
50.01
38.84
48.48
34.21
102.19
Average
1.71
2.19
2.23
3.30
2.12
2.19
1.84
1.61
1.29
1.56
1.10
3.30
Daily - MGD
Maximum
-
-
4.05
6.08
6.04
6.04
4.20
5.75
4.01
4.84
3.09
8.00
Minimum
-
-
1.07
1.48
1.35
1.30
1.00
0.95
0.94
0.99
0.64
1.01
1973 Total Flow:
Average Daily:
Maximum Daily;
Minimum Daily;
744,490,000 Gallons (2,817,894 cu m)
2,036,000 GPD (7,706 cu m/Day)
8,000,000 GPD (30,286 cu m/Day)
640,000 GPD (2,422 cu m/Day)
90
-------
TABLE 21. SUMMARY OF INFLUENT PLANT FLOWS
Hatfield Township Municipal Authority
1974
Month - MG
January
February
March
April
May
June
July
August
September
October
November
December
Total
87.24
22.26
66.05
70.40
42.19
61.78
39.73
37.09
52.39
51.04
35.93
71.55
Average
2.81
0.80
2.13
2.35
1.36
2.06
1.28
1.20
1.75
1.65
1.20
2.31
Daily - MGD
Maximum
6.28
1.47
5.89
4.95
3.35
4.71
2.27
2.18
3.64
4.95
2.13
5.94
Minimum
1.66
0.50
1.14
1.20
0.82
1.70
0.88
0.92
0.74
1.17
0.95
1.26
1974 Total Flow:
Average Daily:
Maximum Daily;
Minimum Daily;
637,650,000 Gallons (2,413,505 cu m)
1,741,000 GPD (6,589 cu m/Day)
6,280,000 GPD (23,769 cu m/Day)
500,000 GPD (1,892 cu m/Day)
91
-------
TABLE 22. RECYCLE FLOWS - MARCH 1973
DAILY AVERAGE
Source Volume - MGD
Pressure Filter Backwash Water 0.11
Thickener Overflow 0.57
Scrubber Water 0.16
Dewatering 0.01
Vacuum Pumps 0.08
Drain Lines 0.01
TOTAL 0.94 MGD
(1) Based on backwashing each filter once per day
(2) Based on 168 hours/week incinerator operation
92
-------
The 0.94 MGD (3.56 x 10^ cu m/Day) average daily recycle flor for March
1973 was equal to 42% of the daily raw flow to the facility. This in-
creases the hydraulic loading on the plant and can reduce efficiency.
The aeration tanks, for example, with a volume of 562,500 gallons would
have a detention time of 6.05 hours at the average daily raw flow of
2.23 MGD. The addition of the 0.94 MGD recycle flow reduces this to
4.28 hours detention time, which could reduce BOD removal efficiency.
In addition, the two.primary units have a total area of 5,652 square
feet, allowing for an overflow rate of 469 gallons/sq. ft./day. With
the recycle flow added, the overflow rate reaches 662 gallons/sq. ft./day,
potentially generating a solids carry-over problem.
OPERATING DATA REVIEW
The Federal Demonstration Grant served as both an advantage and a dis-
advantage to the Authority personnel in plant operations. The advantages
included provision of funds and a resident engineer; the disadvantages
included non-routine operation for collection of specific evaluation data.
There was no lime feed during June 1973 and during a brief period in
September 1973, the tube settlers were by-passed. In addition, during
the 1972-1973 period, various units were removed from operation to check
for wear, and to assist in training operations personnel. All factors
weighed heavily on plant results.
Raw sewage flows for 1973 are shown in Figure 22. These flows do not
account for the recycle flows mentioned previously. The equalization
basins reduce the effects of the 8:00 A.M. and 8:00 P.M. daily peak flow,
and the 3:00 A.M. daily minimum flow as well as the weekly flow variation
shown in Figure 23 which relate more to the actual February 1973 data.
Plant operations personnel adjust the flow control system as necessary to
maintain a steady flow through the plant. This is accomplished by
adjusting a set point, which regulates the opening of the "Red Valves",
the pinch valves which limit the flow from the equalization tanks. As
the daily flows increase during the week, the settings are changed per-
iodically to insure a gradual increase. Simultaneously, chemical feed
rates are changed to pace chemical feed to flow.
The 5-Day Biological Oxygen Demand in the raw and final effluents are
represented as monthly averages in Figure 24. As flow lessened in the
fall months, the conaentration of BOD5 in the raw waste decreased
slightly, but there was little overall effect on the final 8005.
Chemical Oxygen Demand values are represented in Figure 25. A comparison
of these values, particularly final effluent values, will show no cor-
relation with the BODr values of Figure 24. This virtually complete lack
of any type of correlation was not pursued during the Grant Test Period,
and cannot be explained.
93
-------
ii±m±HBTi±hHd
J...LJ1
_!_{_ I _\_ \_ • _| _• '_ i J "_
r I T~! "; ": f"! !" ?" . "i
I i
r n
i M I i I ! i i
U. J_U_LLLLJTTL
-- .•
'•' I- :-!. . I ' - .
h-M"rnS •!- i^-J TTF i '
Figure 22. Raw Sewage Flows - 1973
-------
4.0
3.0
2.0
1.0
WEEKLY AVERAGE
FOR MONTH
DAILY AVERAGE
FOR MONTH
Figure 23, Flow variations by day of the week, February 1973
95
-------
140
_I20
\
o>
£
Q
-
x
o
o 60
o
o
00
Q
I
IT)
40
20
FINAL EFFLUENT
Figure 24. Raw and Final BODs Values - April 1973-March 1974 - Average Monthly Values
-------
700
e
Q
500
x
o
300
UJ
X
o
200
100
0
NO VALUES
A M
1973
S 0
MONTH
J
1974
M
Figure 25. Chemical Oxygen Demand Values, April 1973-March 1974 - Average Monthly Values
-------
Raw suspended solids values are indicated in Figure 26 and Table 23. In
addition, the average raw suspended solids values for the preceding year,
on a cumulative basis, have been tabulated and plotted. Indications are
that the raw wastewater suspended solids concentrations are increasing.
This may be due to an infiltration/inflow control program in effect. As
the solids concentration increases, operations personnel must regulate
sludge processing rates, since the proportion of dry weight of solids to
volume of liquid will change.
TABLE 23. RAW WASTEWATER SUSPENDED SOLIDS - APRIL 1973 - MARCH 1974
Month
April
May
June
July
August
September
October
November
December
January
February
March
Value - mg/1
85
160.5
116
232
116.8
372.5
246.3
342
269
58.6
235.2
215.3
Average - mg/1
160.6
156.1
130.9
134.2
126.3
146.3
149.5
156.2
180.1
176.6
187.4
197.7
Average 199.6 147.3
Range 58.6 - 372.5 126.3 - 197.7
(1) Average of month and last preceding 11 months (Cumulative average)
Phosphorus values are plotted in Figure 27. In March 1974 the system was
operated for two weeks without tertiary clarification. Polymer and alum
98
-------
350
300
to
Q
o200
to
Q
LJ
Q
z
LJ
0.
CO
Z)
150
100
50
RAW WASTE AVG. FOR
PRECEEDING YEAR __
CUMULATIVE AVERAGE
FINAL EFFLUENT
A M J
1973
S 0
MONTH
J
1974
M
Figure 26. Suspended Solids Values - April 1973-March 1974 - Average Monthly Values Except Where Noted
-------
o
o
14
12
10
o>
e
CO
Z>
tr
o
x
co 6
O
FINAL EFFLUENT
A M
1973
S 0
MONTH
J
1974
M
Figure 27. Phosphorus Values (As P) - March 1973-April 1974 - Average Monthly Values
-------
were dosed directly to the tertiary filter pump wet wells, where there
was no provision for adequate mixing. The phosphorus removals in the
tertiary portion of the plant were poor at this time, 69.1% removal
between the secondary and final stations versus an average 75.2% during
the entire data collection phase.
In September 1973 the lime feed system was down for repairs. During this
time the raw phosphorus was 12.9 mg/1 and the primary effluent phosphorus
reached 8.8 mg/1. The removal efficiency was 31.2% across the primary
for this period, although removals during the entire data collection
phase averaged 41.2%. Overall removals of total phosphorus averaged 90.1%
during the data collection phase and 91.1% during September 1973, indicat-
ing that the extra phosphorus load and failure of primary lime system had
adequate backup on the tertiary system, which maintained a high quality
effluent.
The stream criteria are based upon meeting an average soluble total
phosphate (PO^) value of 0.2 mg/1 with a maximum value of 1.0 mg/1. This
compares to a value of 0.06 mg/1 of total soluble phosphorus (as mg/1 P)
a value rarely achieved. The monthly averages of total soluble phos-
phorus are plotted in Figure 28.
Phosphorus is removed in two locations in the plant, primary and tertiary.
The primary removals are obtained by adding lime to the effluent from the
surge storage tank and precipitating out a calcium phosphate salt.
A typical reaction is shown below:
+ 4 OH~ + 3 HPO^ - >- Ca5OH(P04)3
+ 3H0
In addition, the excess lime is converted to carbonate in a parallel
reaction.
Ca(OH)2 + Ca(HC03)2 - > 2 CaC03
2H20
The lime from the carbonate is recalaimed in some facilities by heating.
CaCo3 Temp .> 18001^ Ca0 + ^
The average value of phosphorus is shown in Table 24. as mg/1 Total
Phosphorus.
The overall removal of phosphorus was 90.1% during the data collection
phase. Various recycle sources added an additional 8.9 mg/1 of Total
Phosphorus, an increase of 128%. The primary units decreased this to
3.7 mg/1 (Figure 29), a removal of 45.6% of the raw phosphorus, or 76.1%
of the raw plus the recycled loading.
There was a reduction of 30.4%, from 2.7 mg/1 to 0.69 mg/1, across the
tube settlers where the alum was added (Figure 30). The secondary system
101
-------
SECONDARY EFFLUENT
A M
1973
Figure 28. Total Soluble Phosphorus Values, April 1973-March 1974 - Average Monthly Values
-------
o
OJ
24
o- 20
i
ST
cc
o
Q-
x
Q-
16
'2
SURGE STORAGE TANK
A M
1973
S 0
MONTH
J
1974
M
Figure 29. Primary Phosphorus Removals, April 1973-March 1974 - Average Monthly Values
-------
o
-p-
SECONDARY EFFLUENT
Figure 30. Tertiary Phosphorus Removal Values, April 1973-March 1974 - Average Monthly .Values
-------
removed 19.3% of the phosphorus fed to it, in either a biological mode
(metabolic uptake) or by capturing small particles which had escaped the
primaries.
TABLE 24. AVERAGE TOTAL PHOSPHORUS VALUES
APRIL 1973 - MARCH 1974
Process Stream Average mg/1
Raw Waste 6.8
Surge Storage 15.5 (130)
Primary Effluent 3.7 45.6
Secondary Effluent 2.7 60.3
Tube Settler Effluent 0.69 89.9
Pressure Filter Effluent 0.85 87.5
Chlorine Contact Tank Effluent 0.67 90.1
(1) % reduction from raw value
The tertiary treatment facility polishes the effluent by use of alum.
The following reactions occur:
A12 (S04)3'14 H20 + 2 P043 > 2 Al P04 ^+3 S042 + 14 H
A12 (804)3-14 H20 + 6 HC03 *• 2 Al (OH)3^ + 6 C02 + 14 H20 + 3S042
Chemical consumption during the data collection phase included an average
lime consumption of 248 mg/1 as CaO and 105 mg/1 as alum.
NITROGENOUS OXYGEN DEMAND
Nitrogen Compounds in Wastewater
Nitrogen is one of the fundamental nutrients required in the life cycle
of all plants and animals. In sewage, the major source of the nitrogen
compounds is from animals, specifically human beings. In some cases,
industrial wastes will contain various nitrogen compounds due to the type
of products being manufactured. Frequently, however, industrial wastes
will be deficient in nitrogen and will require the addition of nitrogen
compounds in order to grow and maintain the biological cultures neces-
sary to stabilize the wastes.
The human body utilizes nitrogen available from plants and other animals
in the form of protein. Within the body, protein is used largely for
growth and repair of muscle tissue. Some may be used for production of
105
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energy. The waste products of the body are released in the form of feces
and urine, which contain excess nitrogen compounds.
The feces contain major amounts of unassimilated protein (organic nitro-
gen) . During transmission to the sewage treatment plant some of the
protein is converted to ammonia by saprophytic bacteria. This can be
described as follows:
Protein (Organic Nitrogen) + Bacteria ** NH3
In urine, the nitrogen exists primarily as urea, which is hydrolyzed to
form ammonium carbonate. The enzyme urease causes the reaction, as
follows:
^ NH2
C = 0 + 2H20 -gnzyme>. (NH4)2 C03
z Urease ^ L °
NH2
Nitrites and nitrates found in raw sewage are generally in concentrations
of less than 1 mg/1 because, under anaerobic conditions, nitrites and
nitrates tend to be reduced to free nitrogen gas. Since nitrites are not
stable, the concentration of nitrites in wastewater has little signifi-
cance on the nitrogenous oxygen demand.
The relationship between carbon and nitrogen compounds is shown in Table 25,
for a conventional secondary treatment process.
As indicated in Table 25, 90% of the Carbonaceous Oxygen Demand has been
satisfied. The oxygen demand of the organic matter, however, in only
1.5 mg/1 per mg/1 organic matter. The oxygen demand of the NH3 is 4.5
mg/1 per mg/1 NH3, therefore, requiring a higher degree of treatment.
Even though 90% of the carbonaceous oxygen demand has been satisfied,
only 74% of the total oxygen demand has been satisfied.
TABLE 25. RELATIONSHIP OF CARBON OXIDATION AND NITROGEN OXIDATION
IN WASTEWATER TREATMENT
mg/1
Wastewater Final Effluent
Organic Matter 250 25
Oxygen Demand 375 37
NH3 25 20
Oxygen Demand 112 90
Total Oxygen Demand 487 127
Percent Oxygen Demand Due to NH3 22% 71%
106
-------
Nitrogen Compounds and the Receiving Waters
Nitrogen compounds in sewage treatment plant effluents are more or less
undesirable, depending upon the compound discharges.
Organic Nitrogen
The majority of the organic nitrogen entering the facility appears to
be broken down during cell metabolism or used in all growth. As a
result, the effluent organic nitrogen is low.
Ammonia
The major effect of ammonia discharge is to reduce or deplete the oxygen
available for aquatic life in the stream. Once the carbonaceous mat-
erials are removed or reduced, there is oxygen available to nitrifying
bacteria in the stream to oxidize the ammonia to the nitrate form.
Four atoms of oxygen are required on a stoichiometric basis to oxidize
one molecule of ammonia. On a weight basis, slightly less than 4.6
pounds of oxygen are required to convert 1 pound of ammonia to the
nitrate form.
It becomes obvious that, with the substantial amount of oxygen required
to convert ammonia to the nitrate form, the nitrogenous load on a stream
can cause serious reductions, and in some cases complete depletion of
all dissolved oxygen.
The disadvantages of ammonia nitrogen in effluents can be summarized as
follows:
1. Ammonia consumes dissolved oxygen in the receiving water;
2. Ammonia reacts with chlorine to form chloratnines which are
less effective disinfectants than free chlorine;
3. Ammonia is toxic to fish life;
4. Ammonia is corrosive to copper fittings;
5. Ammonia increases the chlorine demand at waterworks down-
stream from the point of discharge of the sewage treatment
plant.
Nitrates
High concentrations of nitrates in drinking waters can cause problems
for some young babies. Nitrates in food and water are normally
denitrified to nitrogen gas by bacteria in the intestines. However,
some newborn infants do not have a complete intestinal flora. The bac-
teria which are present reduce the nitrates to nitrites, which then
107
-------
combine with hemoglobin to produce methemoglobinemia. This problem is
characterized by the morbid condition in which the surface of the body
appears blue. The 1962 U.S. Public Health Service Drinking Water Stan-
dards limited nitrates to 10 mg/1 N03-N as a maximum concentration.
1. Nitrates are a source of oxygen for certain bacteria and
help prevent septic conditions;
2. Nitrified effluents are more effectively and efficiently
disinfected by chlorine treatment;
3. A nitrified effluent usually contains less soluble organic
matter than the same effluent before nitrification.
It is apparent that the overall effect of nitrates on the receiving
waters depends upon the amount of dilution water available in the
receiving stream and upon the downstream usage.
Nitrogenous Oxygen Demand in the Commonwealth of Pennsylvania
The Commonwealth has required the satisfaction of the oxygen demands
which can be exerted by nitrogen compounds, in some plants since 1970.
This policy, although perhaps not clearly enunciated, can be determined
by examination of the equation used by the Commonwealth to calculate the
Total Biochemical Oxygen Demand (BOD^). The equation used is:
BODT = 1.5 (BOD5) + 4.6 (NH3'N)
The first term in the BODT equation, 1.5 (6005), is an approximation
used to convert the 5-day oxygen demand of the carbonaceous BOD to its
ultimate oxygen demand. Although the factor will vary from waste to
waste, it is a reasonable approximation.
The second term in the BODT equation, 4.6 (NH-j'N), is a reasonable approx-
imation of the oxygen demand which could be exerted by the ammonia in the
sewage treatment effluent. Essentially, this term says that 4.6 pounds
of oxygen are used to stabilize 1 pound of ammonia, as discussed previously,
Although the requirements of the Commonwealth will vary from stream to
stream, the criteria specified can be achieved, except in cold waste-
waters, by good BOD5 removal and by conversion of the ammonia to the
nitrate form (biological nitrification).
Biological Nitrification at the Hatfield Township Waste Treatment Plant
The construction permits issued to the Hatfield Township Municipal Auth-
ority were revised after the completion of design, to require satisfac-
tion of the oxygen demand due to the nitrogen compounds in the effluent.
This can be accomplished by biological nitrification.
108
-------
The conditions for biological nitrification of municipal effluents have
been worked out by Downing and Hopwood in the article, "Some Observations
on the Kinetics of Nitrifying Activated Sludge Plants", who showed that:
"...to achieve nitrification consistently, the period of
aeration must exceed a minimum value which is a function of
the concentration of activated sludge, the temperature, and
the strength of the sewage. When conditions are favourable
for nitrification, the rate of nitrification and rate of
consumption of oxygen due to this process will tend to an
equilibrium level which is proportional to the concentra-
tion of activated sludge under aeration."
The original parameters used in the design of the Hatfield Township
advanced waste treatment plant provided for each aerator to be capable
of transferring 100% of the theoretical oxygen needed to achieve the
specified BOD reduction. This was done in order to provide backup for
mechanical failure, and also to have additional oxygen available to
achieve biological nitrification when required.
Appendix E consists of calculations which demonstrate that, with the
oxygen transfer capability and detention times provided in the advanced
waste treatment plant, as constructed, it should be possible to achieve:
1. 78% nitrification of the influent ammonia at a winter waste-
water temperature of 51° F (10.75° C); and
2. 94% nitrification of the influent ammonia at a summer waste-
water temperature of 77° F (25° C).
It should be noted in analyzing Appendix E that the following factors
affect the ability of the plant to achieve nitrification:
1. At the winter condition, no beneficial credit was given to
the fact that the pH of the mixed liquor will be in the opti-
mum range of 7.5 to 9.3. The bacteria which oxidize ammonia
and nitrites function most efficiently in this range. Test
work has demonstrated that at a pH of 8.4, the rate of oxida-
tion of ammonia by the nitrifying organisms is maximum.
2. During the,winter the stream will generally contain more dis-
solved oxygen than in the summer due to the lower degree of
activity of all organisms (particularly the nitrifiers) at
colder temperatures, and the increasing solubility of oxygen
in water with decreasing water temperature.
3. The assumed BOD5 removal across the primary treatment units
was estimated at 60%. Better BOD5 removals across the primary
treatment units will make more oxygen available to the nitri-
fying organisms in the aeration tanks.
109
-------
4. Lime precipitation at the primary treatment step removes more
of the elements which are toxic to the nitrifying organisms
than would occur in a plant without lime precipitation.
Analytical Problems
All analyses were performed at the Hatfield Township Municipal Authority
laboratory by employees working under normal operating conditions for a
small municipal wastewater treatment plant. Tests were performed in
accordance with standard methods except for the use of the membrane method
for Fecal Coliform.
The nitrogen analytical procedures were especially difficult. The use of
the Nesslarazation nethod for Ammonia-Nitrogen was replaced by the Kjel-
daht method, which is more reliable, however, more expensive. This also
produced organic-nitrogen values. The results in the early data collec-
tion phase are questionable.
PLANT PERFORMANCE
The ammonia-nitrogen values varied greatly during the test period, (see
Figure 31) There was consistent reduction in the ammonia, however, reduc-
ing the oxygen demand of the effluent. At those times when there were
neither human nor mechanical problems, the Nitrosomes and Nitrobacter
enjoyed a stable environment and a nitrified effluent was produced.
The combination of BOD^ satisfaction with biological nitrification in a
single reactor, while theoretically possible, is dependent upon many
factors, including:
1. No mechanical failures
2. Consistant flow rates
3. Constant NH3 feed
4. Minimal sludge wastage
At certain periods the nitrification in Hatfield was extremely satisfac-
tory. At other times it was a victim of operator error, equipment mal-
function, or infiltration/inflow.
The secondary clarifiers developed a build-up of floating solids during
those times that nitrification was occurring. It was theorized that this
was the result of denitrification occurring in the secondary clarifiers.
During denitrification, nitrogen gas if formed, and the gas bubbles tend
to "float" the sludge. The sludge sinks rapidly when hit with a heavy
spray of water.
110
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°"IOO
ro
x
80
£60
o
40
RAW WASTE
AVERAGE RAW WASTE
51.1 mg/l ,
o
5
20
AVERAGE FINAL EFFLUENT I6.7mg/l
FINAL EFFLUENT
A
1973
A S 0
MONTH
N D
J F
1974
M
Figure 31. Ammonia-Nitrogen Values, April 1973-March 1974 - Average Monthly Values
-------
FECAL COLIFORM
Fecal coliform values are given in Table 26. As indicated during the
first three months of the grant, the effluent was not in compliance with
State coliform criteria. Once plant operations personnel determined the
correct operations of the flow control and chlorination systems, however,
they instituted a program to maintain the minimum chlorine residual of
1.0 mg/1 and have produced a fecal coliform-free effluent. No attempt
has been made to determine potential side effects caused by excess chlor-
ination.
TABLE 26. FECAL COLIFORM ANALYSIS
April 1973 - March 1974
All Values in Colonies/100 ml x 106
Raw Final
April 0.96 0.57
May 3.001 0.002
June 2.174 0.002
July
August 1.853 0
September 1.513 0
October 0.392 0
November 0.181 0
December 0.08 0
January 0.18 0
February 0.04 0
March 0.07 0
UNIT PROCESS EFFICIENCIES
On^the following pages a series of curves demonstrating the removal eff-
iciencies of the unit process operations, during the period April 1973
through March 1974, for various contaminants are presented.
112
-------
BOD5 removal efficiencies are plotted in Figure 32. There is an increase
in BOD5 through the surge storage tank due to internal recycles and
resolubilization of organic sludges. The greatest net change is 64.4%
removal across the secondary system. There is continued BOD5 removal
across the entire treatment facility.
Suspended solids removals are presented in Figure 33. The greatest net
change is in the primary clarifier where the reduction is from 1251.9
mg/1 to 98.9 mg/1, a 92.1% removal. Unfortunately, this is based upon
raw suspended solids and recycle solids. The percent removal from the
raw waste alone was 50.5%. The secondary system, on the other hand,
reduced the 74.0 mg/1 suspended solids fed to 14.9 mg/1, a reduction of
79.9%. The recycled solids do not clarify out easily in the primary
clarifiers. When the relatively high solids primary effluent comes in
contact with the activated sludge the biological floe may act as a poly-
merizing agent and cause it to settle out in the secondary clarifiers.
The recycling of the primary sludges tended to add to the overflow sus-
pended solids, while it aided in the prevention of plugging of sludge
withdrawal pipelines caused by the rapidly settling chemical, primary
sludge.
Chemical oxygen demand decreases through the treatment facility are
shown in Figure 34. There is an increase of COD in the surge tank with
a sharp decrease in the primary. There is a gradual decrease, indicating
a marginal degree of removal of the COD, in the secondary and tertiary
systems.
The efficiency of removal of phosphorus is shown in Figure 35. As in the
other cases, there is a marked increase from recycle streams, in this
case an additional 128%. The primary units removed 45.6% of the total
phosphorus in the raw waste with lime. When one considers the recycle
streams increased the total phosphorus to 15.5 mg/1, the unit removed
76.1% of the phosphorus while operating at a pH of 9.5. The secondary
system removed an additional 27% of the phosphorus in the primary eff-
luent for an overall primary-secondary reduction of 49.7% of the raw, or
82.6% of the primary influent. The tertiary-filter system removed 75.2%
of the secondary effluent phosphorus with a slight pick-up through the
filters. Overall reduction was 90.1%.
From a process efficiency viewpoint, the advantages of flow equalization
were somewhat offset by the increases in solids, organics and phosphorus.
It is possible that many plants have a similar problem with digester
supernatent, or incinerator scrubber water, and/or filtrate or centrate.
The problems may be so difficult to detect that plant personnel might
not recognize their existence until the facility begins to produce a poor
quality effluent.
113
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UJ
a:
UJ
O
X
o
<
o
UJ
I
o
o
>-
Q
)
m
\25
100
,119.8
RAW SURGE PRIM. AERATION SEC. TERT FILT. FINAL
UNIT PROCESSES
Figure 32. Percent BOD5 Remaining, April 1973-March 1974 - Average Values
-------
427.0
5
UJ
CO
150
50
25
0
RAW SURGE PRIM. AER. SEC, TERT. FILT FINAL
Figure 33. Percent Suspended Solids Remaining, April 1973-March 1974
-------
125
0
RAW SURGE PRIM. AER. SEC. TERT. FILT. FINAL
Figure 34. Percent COD Remaining, April 1973-March 1974 - Average Monthly Values
-------
o
CO
<
-------
OPERATING COSTS
A major factor in process selection is the Cost/Benefit ratio. By this
is meant, the greatest benefit for the lowest cost. The costs incurred
in operating the Hatfield Township facility are shown in Table 27.
TABLE 27. ANNUAL OPERATING COST x $1000
Salaries and Fringe Benefits
Sludge Hauling
Utilities
Ash Disposal
Chemicals
Administration
Maintenance, Plant
Maintenance, Collection System
Maintenance, Vehicles
Laboratory Supplies
TOTAL OPERATING COSTS
1973
188.2
-
65.9
4.3
33.7
10.0
36.6
8.9
2.2
2.0
351.8
1974
286.1
15.8
90.4
5.3
43.0
12.8
31.1
6.2
5.4
6.9
504.0
The total operating costs for 1973 were $351,800, and for 1974, $504,000.
Plant flows for these periods totaled 745.0 and 637.5 million gallons
respectively for the average operating costs of $472.21 and $790.59 per
million gallons. The largest single cost was labor at $188,200 and
$286,100, or $256.62 and $448.78 per million gallons. Utilities repre-
sented the next major expenditure at $88.46 and $141.30 per million
gallons. The chemical costs for 1973 and 1974, in turn, are broken
down in Table 28.
TABLE 28. CHEMICAL COSTS $/MILLION GALLONS
Lime as CaO
Alum
Polymer
Chlorine
1973
$11.
16.
2.
3.
$33.
45
17
69
37
68
1974
$20.
24.
6.
2.
$53.
26
49
37
55
67
April
March
$13
18
3
3
$38
'73 -
'74
.65
.25
.61
.17
.68
118
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The removal of phosphorus is one of the major design objectives at the
Hatfield plant. During the test period it is estimated that 22,746
pounds of phosphorus were removed from the raw waste in the primaries
with lime and 12,480 pounds in the tertiary system using alum and poly-
mer. Chemical costs for phosphorus removal in the primaries with lime
was approximately $0.44 per pound of phosphorus removed. The cost of
chemicals for tertiary treatment amounted to $1.29 per pound of phos-
phorus removed.
In January 1974 there was a general increase on chemicals. Lime
increased to $24.07 per ton, and alum in 100 pound bags to $86.02 per
ton, whereas the cost in 1973 was $22.50 and $70.20 per ton respectively
119
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SECTION VII
EXPERIENCE WITH EXISTING SLUDGE HANDLING
AT THE HATFIELD AWT FACILITY
BACKGROUND
The sludge handling facilities at the Hatfield Township plant were
designed to handle the sludges produced by the original 1.0 mgd (3,785
cu m/Day) conventional activated sludge process plant. They consist of
duplicate 4' x 4' (1.22 m x 1.22 m) rotary vacuum filters and a 5-hearth
10'-9" (3.28 m) I.D. multiple hearth furnace with 235 square feet (21.83
sq. m) of area. The furnace was designed to handle 1,750 Ibs/hour (794.5
kg/hour) of wet sludge at 30% T.S. Each vacuum filter is capable of pro-
ducing one ton of wet sludge with provision for conditioning with lime
(as Ca(OH)2) and FeCl3. The furnace design rating was 7.5 Lbs/SF/hour
(86.4 kg/sq m/hour) of wet sludge, although at times this was exceeded
with conventional sludges with no problem. When operating at 1,750 Ibs/
hour (794.5 kg/hour) of wet sludge, the 50 ft2 (4.65 sq m) of vacuum
filter area resulted in a filtration rate of 35 Ib/ft2/hour (170.9 kg/sq
m/hour) of wet sludge.
It should also be pointed out that there was provided an 18' 0 x 10'-6"
SWD (5.49 m 0 3.20 m SWD) gravity thickener to thicken the mixed primary
and secondary sludges. The design of the hydraulic expansion with AWT
processes was begun in 1968, and the knowledge of sludge production of
the various units of operation was uncertain. It was, therefore, decided
to provide an extra gravity thickener and not design the expanded sludge
processing facilities until such time as actual operational data on sludge
production would be generated. An arbitrary rating of 2.5 mgd (9,462.5
cu m/day) was assigned to the facility due to the limited solids facil-
ities.
SLUDGE PRODUCTION
A review of late 1973 operating conditions at the facility, as well as
chemical purchased, indicates the following chemical doses were used,
based on total plant flow.
Lime - 248 mg/1 as 90% available CaO
Alum - 110 mg/1 as A12(804)3--16 H20
As a result, the sludge production is summarized in Table 29.
120
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TABLE 29. SLUDGE PRODUCTION - ESTIMATED, JUNE 1974
Primary Sludge
WAS
CaC03
Ca5OH(P04)3
Aluminum Hydroxide and
Aluminum Phosphate
TOTAL
Ibs/mg
1,668
330
3,345
360
271
5,974
g/cu m
200.16
39.60
401.40
43.20
32.52
716.88
These quantities differ with the theoretical figures used in a June
1973 report on sludge disposal, since that report was based upon lime
dose of 420 mg/1 as Ca(OH)2, alum dose of 150 mg/1, 8 mg/1 P removed in
the primary, and 2 mg/1 removed in the tertiary. They compare with an
average sludge processed of 7,033 Ibs/mg (844 kgs/cu m) for the period
July 1973-June 1974, as shown in Table 30.
TABLE 30. SLUDGE PRODUCTION
(Includes Recycles)
Month
July '73
Aug.
Sept.
Oct.
Nov.
Dec.
Jan. '74
Feb.
March
April
May
June
Average
mgd
1.8
1.6
1.3
1.56
1.14
3.30
2.83
2.09
2.13
2.35
1.88
2.06
2.00
Plant Flow
1,000
cu m day
6.81
6.06
4.92
5.90
4.31
12.49
10.71
7.91
8.06
8.89
7.11
7.80
7.50
tons /day
5.25
7.72
5.79
6.77
4.49
4.63
5.05
4.00
7.94
7.14
8.56
10.95
6.52
Sludge
kgs/d
4,767
7,010
5,257
6,147
4,077
4,204
4,585
3,632
7,210
6,483
7,772
9,943
5,924
Processed
Ib/mg
5,833
9,650
8,908
8,679
7,877
2,806
3,560
3,820
7,440
6,080
9,100
10,640
7,033
g cu m
700
1,158
1,069
1,042
945
337
427
458
893
730
1,092
1,277
844
121
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GRAVITY THICKENING
Reviewing the gravity thickener requirements, for a 1 mg (3,785 cu m)
flow, 512 square feet (47.56 sq. m) is required on a floor loading basis.
With an average flow of 2.0 mgd (7,570 cu m/day), a minimum area of 1,024
square feet (95.13 sq. m) is required. The existing gravity thickener
is 40' 0 x 10' SWD (12.2 m 0 x 3.05 m SWD), with 1,256 square feet
(116.68 sq. m) which indicates that the thickener has enough capacity.
Limitations of the furnace, however, have led to an overloaded situation.
This has resulted in a fairly consistent operational problem, with the
finer, more difficult to dewater, solids not settling and thickening.
In the early stages of operation, prior to WAS production and alum usage,
high lime doses were fed in the primary system. Sludge production was
estimated as shown in Table 31.
TABLE 31. SLUDGE PRODUCTION, JANUARY-MARCH 1973
Primary Solids
CaC03
Ca5OH(P04)3
Lb/Day
3,400
8,800
720
12,920
Kg /Day
1,543.6
3,995.2
326.9
5,865.7
At the same time the waste primary sludge flow rate was 250 gpm (5.8
I/sec) at 4,500-5,000 mg/1 SS, or 6,432 Lb/d (2,916 kg/d). During the
time only primary sludges were being processed, the thickened sludge
averaged 8-14% TS. At the same time the vacuum filter was loaded at
11.8 Lb/ft2/hr. (57.62 kg/sq m/hr) and produced a cake of 30-40% TS.
The maximum allowable overflow rate on the gravity thickener is 800 gal/
sq. ft/day (32.64 cu m/day/sq m) or 1.009 mgd (3,851 cu m/day). Primary
sludges are wasted at 250 gal/min. (15.8 I/sec); secondary at 50-100 gal/
min. (3.16-6.31 I/sec); the aluminum waste sludge pumps at 60-1,200 gal/
min. (37.86-75.72 I/sec); scum at 90-100 gal/min. (5.68-6.31 I/sec) (4
pumps); and the thickener dilution water at 150-300 gal/min. (.9.47-18.93
I/sec). The result is a potential hydraulic load of 2,230 gal/min.
(140.71 I/sec), which would overload the facility by a factor of 3. The
operators, therefore, either operate the waste pumps at reduced rates
or stagger the pump operations. Neither of these methods of operations
is ideal. The provision of a second gravity thickener with 50' 0 (15.24
m 0) would allow for future anticipated solids loadings to 4.0 mgd
(15,140 cu m/day) and permit an additional 1,090 gpm (68.78 I/sec) over-
flow rate, if necessary.
The present operating conditions result in a thickened sludge to dewater-
ing of 7.5-8.5% TS and an overflow of 2,000-6,000 mg/1 suspended solids.
122
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In general the flows to the thickenera are now:
Volume/Day
Primary:
300 gal/min x 1,440 min/day = 432,000 Gallons
18.93 I/sec x 86,400 sec/day = 1.64 x 106 Liters
WAS:
1,001 gal/min x 3 shifts x 90 min/shift x 2 - 54,000 Gallons
6.31 I/sec x 3 x 90 x 2 x 60 sec/min - 0.204 x 106 Liters
CWS*:
900 gal/min x 4 pockets x 3 shifts x 15 min/shift 162,000 Gallons
56.8 I/sec x 4 x 3 x 15 x 60 sec/min = 0.613 Liters
Scum:
380 gal/min x 15 min/shift x 3 shifts/day = 17,000 Gallons
24 I/sec x 15 x 3 x 60 sec/min = 0.065 x 106 Liters
*CWS - Chemical (Alum) Waste Sludge
The thickener overflow usually is turbid and at best has an overflow sus-
pended solids of 2,000-6,000 mg/1. The addition of 0.5-1.0 mg/1 anionic
polymer to the thickener feed resulted in a clearer liquor.
SLUDGE DEWATERING - EXISTING VACUUM FILTERS
In order to incorporate the best available technology on the dewatering
of the various sludges, a program was entered into to compare the existing
drum type vacuum filters with a filter press and a centrifuge.
As indicated in Table 32, the average monthly sludge loadings were 237.6
tons/month of sludge dewatered to 30.1% TS and 48.4% VS.
The average wet sludge filter loadings for the first six months in 1974
were 30.9 Ibs/sq. ft/hr (150.9 kg/sq. m/hr), with an average cake concen-
tration of 24-28% TS, after conditioning with 0.3% FeCl3 and 8.7% Ca(OH)2,
Operating hours for the solids handling units are shown in Table 33.
123
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TABLE 32. SUMMARY OF SLUDGE OPERATIONS
MARCH 1973 - JUNE 1974
Month
Mar. '73
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Jan. '74
Feb.
Mar.
Apr.
May
June
TOTAL 3
AVG.
Tons/D.S.
258.6
277.5
336.3
290.6
176.8
253.9
191.3
218.5
146.7
156.0
177.5
131.0
282.3
238.5
296.4
369.3
,801.2
237.6
% T.S.
40.5
40.5
40.5
43.0
24.0
26.5
23.0
28.5
30.0
27.5
28.8
25.2
25.2
24.2
27.8
26.5
30.1
% V.S.
55.4
59.7
60.5
56.0
49.0
36.5
40.0
-
-
-
-
35.8
43.6
53.0
-
-
48.4
Lbs.
Fed-,
765
969
1,428
1,275
969
408
612
357
408
561
714
3,315
969
1,785
2,396
2,091
19,022
Lbs.
Ca(OH)?
21,000
21,490
18,890
24,340
22,140
27,920
28.820
34,680
17,015
25,315
24,175
38,420
36,800
70,500
46,560
59,910
517.975
Adusted^1)
Tons D.S.
247.4
267.4
323.5
279.0
162.8
239.2
173.8
209.8
134.7
143.6
156.6
112.1
246.2
214.1
265.4
328.6
3,504.0
219.06
# FeCl3
100 Lb DS
0.20
0.27
0.20
0.17
0.13
0.13
0.10
0.10
0.21
0.25
1.06
0.43
0.36
0.55
0.39
0.35
0.30
# Ca(OH)2
100 Lb DS
4.34
3.53
3.76
3.97
8.59
6.03(2)
10.00
4.06
9.39
8.42
12.26
16.42
14.32
10.87
11.29
12.05
8.70
(!) Adjusted for 8.7% Ca(OH>2 and 0.3% FeCl
(2) Switched to Dolimitic Limo
-------
TABLE 33, SLUDGE OPERATIONS - 1974
Hours / Operations
Month
Jan.
Feb.
March
April
May
June
Filtration
(2 units)
984
888
1,464
1,296
1,248
1,344
Multiple Hearth Incinerator
744
504
744
648
624
672
FILTER PRESSING SLUDGES
The filter press used was an Edwards and Jones unit with 12' x 12' x 1"
(0.305 m x 0.305 m x 2.54 cu) plates. The results are summarized in
Table 34. With a feed of 15% Ca(OH)2, or 15 Ib. (6.81 kg) of lime to
100 Ib. (45.4 kg) of wet sludge, the unit produced a cake of 41% solids
and a bulk density of 78 Ibs/ft3 (1,248 kg/cu m). This compares to oper-
ation at the rate of 3.25 Ibs/hr (1.48 kg/hr). The filtrate averaged
19 mg/1 suspended solids.
CENTRIFUGATION OF SLUDGES
A series of tests were run utilizing a Sharpies Super-D-Canter on various
sludges at the Hatfield AWT facility. Hercules 814.3 Poly-electrolyte
was used on all cases. The results of the tests on the primary sludges
are shown in Table 35. As indicated, when maximum recovery was : aght
the cake concentration varied from 19.6-39.2% T.S., with recoveries
ranging from 99%-96%. When maximum cake concentration was sought values
ranged from 39.2% to 28.2% T.S., with recoveries falling off to between
96-81%.
It was noted that the chemical primary sludges were much finer than normal
primary sludges. Polymer was needed to obtain a continuous solids dis-
charge at low rates. Process results did not vary significantly with
change in speed differential or pond depth.
125
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TABLE 34. FILTER PRESS TEST DATA - NOVEMBER 1973
Chemical
Addition
Ca(OH)2
%
20
15
10
5
10
15
15
10
Slurry
Concen.
%
8.0
7.6
8.0
7.6
5.5
5.0
5.3
5.0
Cycle
Time
Hours
1.0
1.0
1.0
1.75
1.75
1.3
2.0
2.5
Cake
Solids
%
47
48
41
35
40
41
41
40
Uncond .
7.6
7.5
7.6
7.1
7.5
7.0
6.9
PH :
, Cond. :
11.6
11.4
11.2
11.4
11.8
11.4
11.0
Bulk
Density
Lbs/FtJ
75
75
77
76
78
78
81
79
Cake
Thickness
Inch
1.0
1.0
1.0
1.0
1.0
1.0
1.25
1.25
cm
2.54
2.54
2.54
2.54
2.54
2.54
3.175
3.175
Lbs/Ft3 x 16 = Kg/cu
m
TABLE 35. CENTRIFUGE TESTS DECEMBER 1973
PRIMARY SLUDGE
Gallons
Per
Minute
1.0
5.3
1.2
1.2
3.3
1.2
Thickened
Sludge
% S.S.
0.49
1.07
1.05
1.05
1.12
1.05
Cent.
Cake
% T.S.
19.6
22.8
39.2
39.2
30.0
28.2
Recovery
%
99
97
96
96
81
91
Polymer
#/T
12.0
8.4
8.0
8.0
2.6
4.6
gm/kg
6.0
4.2
4.0
4.0
1.3
2.3
Machine Rated at 60 gal/min (3,786 I/sec) maximum.
Gallons/minute x .0631 =- I/sec.
#/T x 0.05 - %
126
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Possible reasons for the fine sludge characteristics are recycle of fines
from the filtrate, pressure filter backwash and thickener overflow. In
addition, the surge mixers and flash mixers could shear the natural floe
particles and yield a fine floe.
The secondary sludge was also tested. The average S.V.I, was 70, and at
no time did it exceed 100. This resulted in an easy to handle cake of
11-12% T.S., as shown in Table 36.
TABLE 36. CENTRIFUGE STUDY DECEMBER 1973
SECONDARY SLUDGE
Gallons
Per
Minute
4.6
4.5
4.1
Thickened
Sludge
% S.S.
0.74
0.74
0.74
Cent.
Cake
% T.S.
12.1
11.6
11.9
Recovery
%
100
100
99
Polymer
#/T
6.2
3.8
5.7
3.1
1.9
2.85
2.2
2.8
0.84
0.73
0.73
23.5
15.2
14.3
95
82
72
0.0
5.5
4.7
0.0
2.75
2.35
It must be pointed out, however, that the secondary system removed a large
percentage of the suspended solids which escaped the primary clarifiers.
It was assumed that much of this was caught up in the WAS, and since it
was predominantly CaC03, it served as an excellent weighting agent. The
WAS, in turn, had a polymerizing effect and aided in the secondary clar-
ification, producing a cake with better dewatering characteristics than
conventional sludges.
The tertiary alum sludge was centrifuged and the results are shown on
Table 37. The alum sludge values of 12-21% T.S. with 99-100% recovery,
or 32-35% T.S. with 60-80% recovery, is relatively high according to the
Sharpies personnel. There was a problem of obtaining a representative
sample of the alum sludge, since the wasting of the chemical sludges is
accomplished on a "batch-basis" rather than continuous. There is prob-
ably carryover from the primaries all the way through to the tertiary
system.
127
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TABLE 37. CENTRIFUGE STUDY DECEMBER 1973
TERTIARY (ALUM) SLUDGE
Gallons
Per
Minute
4.6
4.5
2.3
3.3
3.0
1.7
1.7
Liters
Per
Second
0.29
0.28
0.15
0.21
0.19
0.11
0.11
Thickened Cent
Sludge Cake
% S.S. % T.
0.7
0.7
2.4
2.4
0.2
0.2
0.2
12.1
11.6
21.3
18.2
35.2
35.0
31.8
There were two additional series of
Secondary/Tertiary and one with all
reported in Table 38 and Table 39,
TABLE 38.
CENTRIFUGE
Recovery
S. %
100
100
99
99
80
72
60
tests run, one
sludge combined
respectively.
TESTS DECEMBER
Polymer
#/T gm/kg
6.2 3.1
3.8 1.9
2.1 1.05
1.7 0.85
14.0 7.0
240.0 120.0
14.0 7.0
with combined
The results
1973
are
SECONDARY /TERTIARY
Gallons
Per
Minute
1.1
2.4
3.5
2.2
1.1
2.0
2.0
Liters
Per
Second
0.07
0.15
0.22
0.14
0.07
0.13
0.13
Thickened Cent
Sludge Cake
% S.S. % T.
2.2
2.3
2.3
2.3
2.2
2.2
2.2
19.4
10.4
10.3
10.2
19.4
13.9
13.3
Recovery
S. %
99
99
98
99
99
86
77
Polymer
Utilization
#/T g
2.4
2.9
3.6
3.0
2.4
0.6
2.7
m/kg
1.2
1.45
1.8
1.5
1.2
0.3
1.35
128
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TABLE 38 (continued). CENTRIFUGE TESTS DECEMBER 1973
SECONDARY/TERTIARY
GPM
L/Sec
% S.S.
% T.S.
Rec.
#/T
gm/kg
TABLE
1.1
0.07
2.2
10.4
98
2.4
1.2
39 . CENTRIFUGE
COMBINED
OPTIMUM
- 2.2 1.1 - 2.0
- 0.14 0.07 - 0.13
- 2.3 2.2
- 19.4 13.3 - 19.4
- 99 77 - 99
- 3.6 0.6 - 2.7
- 1.8 0.3 - 1.35
TESTING DECEMBER 1973
SLUDGES
Gallons Liters
Per Per
Minute Second
2.3 0.15
3.0 0.19
1.3 0.08
2.3 0.15
2.3 0.15
3.0 0.19
2.5 0.15
2.6 0.164
GPM
L/Sec
% S.S.
% T.S.
Rec.
#/T
gm/kg
Thickened Cent
Sludge Cake
% S.S. % T.
x 17.7
x 15.4
4.4 13.8
x 13.3
x 17.7
x 15.4
x 15.2
4.3 15.2
1.3
0.08
4
13.3
99
0.9
0.45
Polymer
Recovery Utilization
S. % #/T
100 1.5
99 0.88
99 2.7
99 2.3
100 1.5
99 0.88
98 2.3
94 2.2
OPTIMUM
- 3.0 2.3 - 3.0
- 0.19 0.15 - 0.19
.4 4.3
-17.7 15.2 - 17.7
- 100 94 - 100
- 2.7 0.9 - 2.3
- 1.35 0.45 - 1.15
0.75
0.44
1.35
1.15
0.75
0.44
1.15
1.10
129
-------
A comparison of the three dewatering devices tested at the Hatfield
facility under similar operating conditions indicated that the filter
press produced a drier cake with greater recovery of solids fed than
either the vacuum filter or the solid bowl centrifuge. The press
operates on a batch process principal, as opposed to the continuous
operation of the centrifuge and vacuum filter.
While these tests proved significant in determining the relative per-
formance of each of the three types of mechanical dewatering devices
on the same sludge, a total cost evaluation, including both amortized
capital and operating costs, would be required before a final selection
is made.
130
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ASH ANALYSIS
The relationship between advanced wastewater treatment processes and the
sludges that they produced were often neglected in the past. In the
Hatfield Township operation, analyses were performed to determine the
characteristics of the incinerator ash, primarily to ascertain what
options were available to the Authority for final disposal, under
current Pennsylvania regulations.
The analysis of June 14, 1973 (Table 40) indicates a high % volatiles.
This is determined by weight loss, however, the weight loss was probably
due to calcination of the CaC03 and loss of C02-
The leaching analysis (Table 41) indicates a stable, inert material,
with a possibility of generating heavy metals in the leachate. This is
a significant factor in limiting the final disposal to generally State
approved sanitary landfills with adequate facilities to capture, and
treat, leachates.
TABLE 40. ASH ANALYSIS - JUNE 1973
Filter Cake Sample - Taken June 14, 1973
Moisture - 67.6%
TS - 32.4%
Analysis
Ca(OH)2
Mg(OH)2 3
CaC03 30
CaxPy 8
Inerts 11
Volatiles 43
103
131
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TABLE 41. CHEMICAL COMPOSITION OF INCINERATOR ASH FROM
HATFIELD TOWNSHIP MUNICIPAL AUTHORITY AWT FACILITY
DECEMBER 1973
Mineral
Calcium
Magnesium
Aluminum
Silicon
Baron
Copper
Iron
Lead
Phosphorus
Sodium
Tin
Titanium
Zinc
(1) Tests done by
(2) In estimating
% (1)
53.040
29.465
9.000
5.000
0.005
0.500
0.900
0.090
0.900
0.500
0.050
0.500
0.050
100.50
Lb. Mineral
Per Ton Ash
1060.8
589.3
180.0
100.0
0.1
10.0
18.0
1.8
18.0
10.0
1.0
10.0
1.0
2000.0
Lb. Material
Leached % Material
Per Ton Ash Leached (2)
256.20 13.81
1.00 0.05
1.00 0.05
1.80 0.09
1.00 0.05
0.10 0.005
-
-
-
-
0.50 0.025
-
_ _
261.60
spectrophotometer and given in relative concentrations
percentages, maximum amounts were used on all para-
meters except calcium and magnesium. On these two, a ratio of 9:5
was presupposed and the percentages arrived at analytically.
Maximum amounts were used except for Tin (Sn) which was assumed to
be partially leached out.
132
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SLUDGE INCINERATION
The existing furnace is a 10'-9" I.D. x 5 Hearth (3.28 m I.D. x 5 Hearth)
Multiple Hearth furnace rated for combusting 1,750 Ib/hour of 60% V.S.S
at 30% T.S. On this basis the furnace rate is 4.82 Ib/ft2/hour of wet
cake. Present technology generally rates furnaces at 8.0 Ib/ft2
(39.06 kgs/sq m). Attempts to exceed 2,000 Ib/hour, or 5.5 Ib/ft2/day,
reduce furnace capacity and form clinkers, or lumps of improperly com-
busted sludges.
Furnace operational temperatures vary, but are generally maintained at
300° F on #1 Hearth, 600° F on #2 Hearth, 1,600-1,700° F on #3 Hearth,
1,300-1,400° F on #4 Hearth, and 700° F on #5 Hearth. There are ade-
quate air pollution control devices to eliminate potential problems.
As indicated in Table 42, the average furnace loading has been 3.25
Ibs/ft2/hour (15.93 g/sq m/hour) of dry solids, or 12.43 Ibs/ft2/hour
(60.91 g/sq m/hour) of wet sludge.
TABLE 42. SLUDGE LOADINGS
JANUARY - JUNE 1974
WET SLUDGE
Month
Jan.
Feb.
March
April
May
June
IQ^kg /month
559.1
471.6
1,016.2
894.0
967.2
1,264.3
tons /month
616.3
519.8
1,120.2
985.5
1,066.2
1,393.6
FILTER
kg/m2/hr
112.6
114.3
149.4
148.4
167.0
202.6
LOADINGS
Ib/ft2/hr
25.1
23.4
30.6
30.4
34.2
41.5
INCINERATOR LOADINGS
kg/m2/hr
34.4
42.9
62.6
63.2
71.0
86.2
Ib/ft^/hr
7.05
8.78
12.81
12.94
14.54
17.65
AVG. 768.9 950.3 150.9 30.9 '60.1 12.30
133
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SECTION VIII
CONSTRUCTION OF WASTE TREATMENT PROJECTS
GENERAL
The construction of both the 1965 and 1970 projects were carried out in
the manner which has prevailed for decades in the United States. In the
United States, municipal construction work has always been awarded on the
basis of competitive bidding, and, in the State of Pennsylvania, has always
required that separate bidding occur for the prime contract functions of
general construction, plumbing construction, heating construction, and
electrical construction. The obvious advantage of competitive bidding
under one entire construction program, with one designated contractor, is
not currently permitted in the State of Pennsylvania under existing laws.
Turnkey construction, that is, development, design, construction, and
operation, has not been, except in very isolated instances, utilized in
municipal work in the United States. This situation, utilized quite
widely throughout other parts of the world, has, in many cases, distinct
advantages over the method employed in the United States, but resistance
is still very high to this approach, and even though the Federal regula-
tory agencies allow turnkey applications, it appears that it may be some
years before a significant movement in this direction can be achieved.
The 1970 construction project differed in many respects from the 1965
construction project in the approach as utilized by the contractors.
The 1970 construction project was far more complicated, in that the units
and processes were far more sophisticated, and also the 1970 project had
to be constructed around the existing facility and the existing facil-
ity had to be maintained, insofar as possible, at its full treatment
capability during the entire construction period. As indicated pre-
viously, the 1970 construction required the integration of the units
which were in service in 1970, primarily because of effluent requirements,
and because the previous construction had occurred only five years
earlier. Experience with this project, and other projects where remod-
elling of existing facilities has been undertaken, has led to a general
conclusion that if the value of any existing unit is even the slightest
bit questionable, it should be abandoned rather than to spend money to
integrate it into a new facility. This general conclusion has severe
limitations, but the experience at Hatfield Township would indicate it
might well have been far better to construct the 1970 project adjacent
to the existing facility, and then to abandon the existing facility upon
completion of the new plant. The problems associated with working
around existing piping and interconnecting existing units with new units,
undoubtedly raised the cost of construction considerably, and there is a
strong question whether there was really any savings in total dollars by
utilizing the existing facilities.
134
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1965 CONSTRUCTION
The 1965 construction was generally straight-forward. There were no
existing utilities on the plant site, and the contractor was free to
undertake the work without any restrictions whatsoever.
The total time of construction of the 1965 project was fifteen months,
and the work proceeded with only minor difficulties. In 1965, the avail-
ability of equipment was well established, and the time period which
elapsed from the placing of an equipment order to the delivery on site
was quite reasonable.
The general contractor, that is the contractor who did all of the build-
ing construction as well as the mechanical installations, was responsible
for coordinating all of the various trades at the project site. There
were some minor difficulties with scheduling the plumbing and heating and
electrical construction concurrently with the general construction, but
by and large, the project proceeded in good harmony. As was quite common
in the middle 1960s, the general contractor was competent in all aspects
of the construction, and did little, if any, sub-contracting to special-
ized trades.
In most respects, the 1965 construction project was typical of that era,
and caused the Hatfield Township Municipal Authority a minimum of problems.
1970 CONSTRUCTION
The contrast between the 1970 construction and that which had occurred
previously in 1965 was marked. Among other things, the trend of construc-
tion by 1970 had undergone a change in that many of the older contractors
who specialized in waste treatment projects, were no longer capable of
bidding larger sized projects, and an entirely new grouping of contractors
were entering the scene, many with little or no experience in the waste
treatment plant construction area.
Another interesting aspect of the 1970 construction, and one which was
not untypical at that time, nor at the present time, was the tendency for
contractors to act as a broker, that is, to sub-contract virtually every
specialized trade, and perform little, if any, services with their own
personnel. As in 1965, the general contractor was responsible for coor-
dination of all of the trades, but with the tendency of the general con-
tractor and the other specialized contractors to sub-contract much of
their work, the problems of coordination among the trades became, at
times, severe.
The problem of providing construction around, and connecting to, existing
facilities has been mentioned, but it provided some particularly difficult
periods during the construction of the 1970 project. Prior to the con-
struction, detailed operational procedures were developed to maintain the
operation of the existing facility, but due to the method of construction
undertaken by the contractor, it was found impossible to maintain full
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operational service at all times, and the service was interrupted on a
number of occasions, sometimes for periods as long as several days.
This caused a number of problems to occur with the State regulatory
agency, which in turn, by reason of their concern, compounded the con-
struction problems in some instances.
One of the striking factors, which became apparent during the 1970 con-
struction, was that the availability of equipment and materials was far
less than that which had occurred in prior years. Delivery times on
even minor items of equipment were considerably longer, and this situa-
tion is now at the present time, even more acute. The construction period
for the 1970 project was twenty-two and a half months, and it is currently
estimated that if the 1970 project were to be placed into the construc-
tion phase at the present time, that the time of construction would
probably extend to twenty-eight or thirty months, occasioned almost
entirely by delays in procuring equipment and materials. This, much
longer time for construction, translates to a higher cost for construc-
tion because all public bidding work in the United States must utilize
minimum wage rates as published by either the U. S. Department of Labor
or the local State Department of Labor. Normally these minimum wage
rates have yearly escalation clauses, hence, the longer a project consumes
the higher the labor costs will be at various stages throughout the project
One requirement placed upon the contractor in the 1970 project, which was
far greater than that which had been required in 1965, was the provision
for detailed and extended instruction in the operation and maintenance of
individual items of equipment. It was the contractor's responsibility
to provide technical instruction from the equipment manufacturer on the
job site, in order that the operators could become familiar with all
facets of each item of major equipment before it was placed in actual
operation.
Actual practice has indicated that this requirement is absolutely essen-
tial in advanced waste treatment construction, and further, that it would
probably be well to require a minimum of two detailed technical instruc-
tions sessions, with perhaps a six month interval.
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SECTION IX
PROJECT COSTS
GENERAL
In the estimating the cost of waste treatment, it has become quite popu-
lar to attempt to reduce, for comparative purposes, the cost of construc-
tion of specific types of treatment processes to a cost per gallon of
capacity provided. These figures, then, are often mistakenly utilized
by governmental agencies, and local authorities, in determining a
general course of action to follow, completely neglecting the individual
characteristics which should and must ultimately influence the decision
in any specific case.
If a development of a cost per gallon treated can be developed with a
full understanding of the major factors which contributed to that parti-
cular cost figure, then the value, or values, become more meaningful in
cost projections for other projects with similar overall characteristics.
The reader is cautioned, that in the data which is developed in this
chapter, the ultimate values are greatly affected by the following:
1. The three construction programs: the 1965 project, the
1970 project, and a 1975-76 project, have a construction
interval of five years, and that the value of the dollars
spent at each period of construction varies considerably.
2. The 1970 project represented a radical departure from the
then prevailing technical thoughts with respect to waste
treatment, and greatly altered the types of units required
to meet the increased effluent criteria. The 1965 con-
struction was integrated into the 1970 project by converting
these 1965 units into other uses, with the exception of the
aeration basin and the solids handling facilities. In
1975-76 construction will, however, supplement the 1970
construction rather than eliminate portions of the process
or modify them to other uses.
3. If there'had been no 1965 project, the construction of the
1970 project could have been more efficiently accomplished
in terms of dollars, inasmuch as there would have been no
need to construct around operating units.
4. In the construction of the 1970 project, it was decided
to provide extra capacity in those units not readily expan-
dable in the future so that succeeding hydraulic expansions
would not require additional units in these areas. The
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ultimate Hatfield facility, as it may exist beyond 1976,
will represent stepped or phased construction, with varying
degrees of construction in each step or phsse, and will
not represent a straight-line relationship as to cost of
the facilities provided per gallon of capacity.
5. In projecting costs for the 1975-76 construction, an
escalation factor has been included, but it is impossible
to predict with even a moderate degree of accuracy, the
conditions that will prevail at that time.
1965 COSTS
The 1965 costs were developed previously in this report and shown in
Table 1. The total 1965 treatment plant construction cost was $848,767.
This sum of money was expended to provide a rational hydraulic capacity
of 1.3 mgd, and a solids handling capability for a flow of 3.6 mgd.
The 1965 construction consisted of a secondary treatment plant, providing
primary clarification, aeration, secondary settling, and chlorination,
with sludge thickening, vacuum filtration and multiple hearth incinera-
tion of the sewage solids. There was, in addition, provided as part of
the sludge control building, office space, meeting room space, and
garage and maintenance facilities.
The unit cost of the 1965 project was $0.65/gallon of treatment plant
hydraulic capacity.
It was anticipated in 1965 that subsequent hydraulic expansions would
increase the plant capacity of 3.6 mgd, and that the subsequent hydraulic
expansion, when required, would probably necessitate the expenditure of
an additional $850,000, with the exact figure dependent upon the infla-
tionary situation which prevailed at the time of the expansion.
Assuming that this reasoning would have followed, the total cost of
expanding to a 3.6 mgd secondary treatment plant, with incineration of
the sewage solids, would have been approximately $1,700,000, or, on the
basis of capacity, $0.47/gallon of hydraulic capacity provided.
1970 COSTS
The construction cost for the 1970 project is summarized in Table 43.
The total construction costs expended for both the 1965 and the 1970
projects, at unadjusted dollars actually spent, was $4,789,197.
On the basis of dollars actually spent, unadjusted for inflation, the
Hatfield Township advanced waste treatment facility at the theoretical
design capacity of 3.6 mgd, cost $1.33/gallon of hydraulic capacity
provided. On the basis of a 5.0 mgd rational design capacity, that is
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the capacity to which the plant could ultimately be loaded and still,
theoretically, maintain a comparable effluent quality; the actual dollar
cost was $0.95/gallon of hydraulic capacity provided.
TABLE 43. HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
CONSTRUCTION COSTS - 1970 PROJECT
ADVANCED WASTE TREATMENT FACILITY
General Construction $3,538,603
Plumbing Construction 72,958
Electrical Construction 328,859
TOTAL 1970 TREATMENT PLANT CONSTRUCTION COST $3,940,420
Total 1965 and 1970 Treatment Plant
Construction Cost at Unadjusted Dollars $4,789,187
Total 1965 and 1970 Treatment Plant
Construction Cost at June 1973
Adjusted Dollars (Based on ENR Indicies) $6,028,805
3.6 mgd Theoretical Capacity
5.0 mgd Rational Capacity
On a rational design basis, and considering both the 1965 and the 1970
projects, one conclusion might be drawn, subject to the limitations
described in the previous section, that advanced waste treatment in the
size range of 3.5 mgd to 5.0 mgd capacity, costs approximately twice as
much as secondary treatment per gallon of hydraulic capacity provided.
This relates to conventional secondary treatment, as opposed to advanced
waste treatment consisting of primary chemical precipitation-complete
mix aeration-tertiary chemical precipitation followed by tertiary fil-
tration. The reader is cautioned that this very general conclusion
should not be utilized for any other process comparison, such as secondary
treatment with physical-chemical advanced waste treatment, or secondary
treatment with advanced waste treatment where the total advanced pro-
cess is concentrated in a tertiary step.
The most recent estimate for expansion of the hydraulic component and
the solids handling component at the Hatfield Township AWT facility was
made in June 1973.
As of June 1973, assuming there had been no prior construction, and the
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total facilities now present were constructed with dollars of the 1973
value, the value of the work which now exists is estimated at $6,028,805.
On the basis of a 5.0 mgd (18,925 cum/day) rational capacity, this fig-
ure translates to $1.20/gallon ($0.317/liter) of capacity provided.
Comparison of this figure, adjusted to June 1973 dollar value, as
opposed to actual dollars spent, indicates an increase of $0.30/gallon
($0.079/liter) of capacity provided, and represents the inflationary
increase between 1965, 1970 and 1973. This fact would emphasize the
extremely limited value of utilizing a cost/gallon of capacity for pro-
jecting future costs of similar type installations.
FUTURE COSTS
Estimated construction costs for the next expansion program at the Hat-
field Township AWT facility, assumed at providing a total hydraulic
capacity of 8.0 mgd (30,280 cum/day) on a two-shift operation basis per
day, or an ultimate solids handling capacity of 16.0 mgd (60,560 cum/day)
are summarized in Table 44.
The total estimated construction cost, if the program is undertaken prior
to 1976 is $5,024,500.
The total value of the 1965, 1970 and future treatment plant construction
costs, at actual dollars spent or estimated, and unadjusted, is $9,823,687,
Based upon the theoretical design capacity of 7.5 mgd (28,388 cum/day),
it is estimated that the total cost will be $1.30/gallon ($0.343/liter)
of capacity provided. On the basis of a rational design capacity for the
future expansion of 10.5 mgd (39,743 cum/day), the cost is estimated at
$0.93/gallon ($0.245/liter) capacity provided.
The figures in Table 45 compare closely to those estimates provided for
the existing facility at a 3.6 mgd (13,626 cum/day) theoretical capacity,
and a 5.0 mgd (18,925 cum/day) rational capacity, and they include the
inflationary costs anticipated to occur over the next fifteen to eighteen
months.
If there had been no 1965 and 1970 construction, but the entire project
was to be constructed within the next fifteen to eighteen months, the
total estimated cost at 1973 adjusted dollars would be $15,842,500.
This translates to a cost per gallon of rational capacity of 10.5 mgd
(39,743 cum/day) of $1.50/gallon ($0.396/liter) of capacity provided.
It is suggested that if the reader desires to draw conclusions as to cost
for the type of process utilized at Hatfield Township, on the basis of
dollars/gallon capacity provided, that as an initial starting figure he
consider a value of $1.80/gallon ($0.476/liter) to $2.00/gallon ($0.528/
liter) of capacity provided. This figure, if utilized at all, should
only be in the very initial analyses of the potential costs for a facility
of this type, and should be refined in further detail as soon as suffic-
ient information is available to permit a revision.
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TABLE 44. HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
ESTIMATED CONSTRUCTION COSTS - 1973 BASE
SOLIDS HANDLING AND HYDRAULIC EXPANSION
General Construction - Hudraulic $1,878,200
General Construction - Solids Handling 2,476,300
Plumbing Construction 95,000
Electrical Construction 575,000
TOTAL ESTIMATED FUTURE CONSTRUCTION COSTS $5,024,500
Total 1965, 1970 and Future Treatment Plant
Construction Cost at Unadjusted Dollars $9,813,687
Total 1965, 1970 and Future Treatment Plant
Construction Cost at June 1973 Adjusted
Dollars (Based on ENR Indices) $15,842,500
7.5 mgd Theoretical Capacity
10.5 mgd Rational Capacity
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SECTION X
FUTURE REQUIREMENTS
GENERAL
At the present time, the Hatfield Township advanced waste treatment fac-
ility is precessing the waste flows from Hatfield Township and a portion
of a neighboring community, Montgomery Township. These two communities
are operating under an agreement established first in 1965, and modified
in 1970 with the initiation of that project. In the 1970 project,
provision was made for acceptance of waste flows from portions of other
communities which lie in the drainage area of the AWT facility.
Since the 1970 project, new regulations have been published by the Envir-
onmental Protection Agency on a Federal level, and the Pennsylvania
Department of Environmental Resources, which require regional planning
for not only wastewater treatment, but also for wastewater management.
These discussions in the Upper Neshaminy area are currently nearing their
final stages, and it appears that the Hatfield Township facility will
have to be expanded to accommodate at least two, and perhaps as many as
four, of the adjacent communities. This fact, together with the growth
patterns prevailing in both Hatfield Township and Montgomery Township,
will dictate an early expansion of existing facilities.
Even prior to this planning, however, the need for expansion of the solids
handling portion of the AWT facility has been known. In the design of the
1970 Hatfield Township advanced waste treatment project, only one addition
was made to the existing solids handling system, and that was the construc-
tion of a new sludge thickener to receive the primary waste activated and
tertiary waste sludge volumes.
At the time of the design of the 1970 project, the exact characteristics of
the future chemical sludges was now known. Parameters for this sludge con-
centration were approximated in bench scale laboratory studies, but the exact
character of these waste sludges ultimately had to be dependent upon the
actual chemical feeds and their combinations once actual operation commenced.
The new sludge thickener was designed with a 40' diameter and a 10' side
water depth (12.2 m diameter x 3 m sidewater depth), and it was estimated
that at a 3.6 mgd (13.63 cum/day) flow this unit would handle a sludge
load totalling 12,960 Ibs/day (5,891 kg/day). This estimated sludge load
was composed of 6,000 Ibs/day of primary sludge, 4,800 Ibs/day of lime
sludge, and 2,160 Ibs/day of waste activated sludge. At the time of the
design, the use of alum at 40 mg/1 was anticipated, or perhaps even a
lesser amount, for polishing purposes prior to the tertiary filtration
step, and the sludge generated from this volume of chemical use was
neglected in the total sludge volume calculation. The design of the
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thickener assumed a feed concentration of 3,500 mg/1, and a 700 gpd/ft^
overflow rate. The thickener overflow was assumed to be composed of
310 gpm of thickener flow, plus 300 gpm of dilution water.
The existing dewatering facilities consisted of two vacuum filters of a
rotary type, with plastic surfaces, each having a capacity of 450 pounds
of dry solids per hour (204.5 kg d.s./hour).
The existing sludge incinerator from the 1965 project was a multiple
hearth furnace with a rated capacity of 1,900 pounds of filtered sludge
cake per hour (863.6 kg/hour).
The existing sludge dewatering and sludge incineration facilities were,
obviously, inadequate to handle the anticipated sludge to be developed
at the design average flow of 3.6 mgd, and in 1969, the estimate was made
that the ultimate limit of these items of solids handling would be reached
at a hydraulic flow in the range of 2.5 mgd (9,462 m^/day). Due to econ-
omic limitations imposed by the local governing authorities in 1969 and
1970, it was decided to defer any additions to the solids handling system
until the operation began to approach 140 hours per week, or 20 hours per
day. This decision, in retrospect, was not completely sound because the
character of the sludge developed has resulted in nearly continuous oper-
ation at flows of 2.0 mgd or less. The present solids handling system is
the weakest portion of the total Hatfield Township AWT operation, and is
in need of immediate expansion. Initial studies have already been
developed for the expansion of these facilities.
A section plan of the one addition to the solids handling units provided
in the 1970 project, the new sludge thickener, is contained in Figure 36.
The sludge handling program, a hold-over from the original 1965 project,
consists of two 4' x 4' (1.22m x 1.22m) Drum-Type Vacuum Filters, with
chemical conditioning, and a 10' x 9" O.D. (3.28 m) Multiple Hearth
Furnace. The system operates at capacity on a 24-hour, 7 day per week
schedule. See Figure 37 for a diagram of the system. The expansion of
the facility to include advanced waste treatment deferred the expansion
of the sludge handling facilities until enough information could be gene-
rated to design an adequate system. Additional information on sludge
handling appears in later chapters.
The need for the expansion of the solids handling facilities has become
so critical that it appears, unfortunately, that a crash program must
be undertaken to find some alternate temporary means of disposal of
accumulated sludge volumes in advance of any new construction, in order
to relieve the load placed on the existing multiple hearth incinerator.
The problem appears to be most critical during the summer months when
the solids in the sludge thickener tend to initiate a condition of sep-
ticity, and thus become less easily dewatered. This reduces the solids
content of the vacuum filtered sludge, which results in the incinerator
burning larger volumes of sludge with a smaller dry solids content.
During the spring of 1973, mixed liquid sludge was removed by tank truck
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.UDGE DRAW OFF PIPE
INFLUENT PIPE
Figure 36. Sludge Thickener Tank
-------
INFLUENT
^^ EFFLUENT
FILTER V
ASH
Figure 37. Existing Sludge disposal system - 1974
-------
on a fairly constant basis, for a two and a half month period, for land
disposal. Investigations are under way to locate a source where vacuum
filtered sludge can be disposed of in a land-fill operation, which would
be far more efficient than removing the sludge by tank truck in a liquid
form.
This thickener condition also affects hydraulic performance by directing
a deteriorated overflow of greater volume to the raw waste pump station,
thus building up the inventory of sludge in the recycle process.
SOLIDS HANDLING
This obvious need for additional solids handling facilities prompted the
Hatfield Township Municipal Authority to authorize the developement of a
report on solids handling expansion, early in 1973. This report was com-
pleted and submitted to the Authority in June 1973. This report explored
in depth ten alternative programs for solids handling expansion, based
upon various combinations of treating chemical primary sludge, waste
activated sludge and tertiary chemical sludge, and considering the pos-
sibility for the various programs of recalcining the lime for reuse in
the process.
As part of the development of this solids handling report, the total
weight of dry solids generated per day per million gallons was developed
for both the conventional treatment facility, as constructed under the
1965 project, and for AWT sludges, as produced in the current operation.
The calculation of these sludge volumes is given Appendix F of this study,
and a summary of the sludge production is shown in Table 29.
The summary of sludge production, as shown in Table 29, indicates the
sludge produced on a dry weight basis. It was recommended in the report
to the Authority that the design of the solids handling expansion con-
sider not only total anticipated future sludge production, but also the
optimum number of hours per week of operation. With 75% Federal funding,
the operating costs may well be in excess of the amortized community share
of capital costs. Hence, the optimization of operating costs sometimes
becomes the dominant economic criteria in process selection.
It may be noted from Table 29 that the conventional sludge generated from
a secondary treatment facility is approximately 1/3 of that which is gen-
erated per million gallons of flow from an AWT facility utilizing the
Hatfield Township process. The reader is cautioned, in reviewing this
data, that the generation of the AWT sludges is dependent on a number of
variables, and will not be identical for each separate facility which may
utilize the Hatfield type process. For instance, the amount of calcium
carbonate and other calcium sludges generated will be dependent upon
the amount of lime necessary to achieve a pH of 9.5, which in turn, is
dependent upon the alkalinity of the raw wastewater. In a similar manner,
the generation of alum sludges is a function of the amount of alum neces-
sary to achieve proper coagulation, which in turn, is in part a function
of the pH of the secondary effluent as it enters the tertiary process.
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It may be generally said, however, that the ratio of AWT sludge to con-
ventional secondary treatment sludge will be in an approximate ratio of
3.5-4:1 for a facility utilizing primary lime precipitation, activated
sludge, and tertiary alum precipitation followed by filtration.
In any waste treatment facility where large amounts of lime are used in
either the primary or tertiary phase, consideration must be given to the
possibility of recalcination of this lime. When lime is used, calcium
carbonate and calcium hydroxyapatite are the major sludges produced.
The hydroxyapatite is fairly stable, but the calcium carbonate can be
recalcined to recover lime. It has been reported by various sources that
there is no change in the recovered lime capability for phosphorus
removal, but the make-up demand will vary considerably. It has been
reported as being as low as 13%, or as high as an average of 25% to 35%.
The classification of the sludge in order to separate CaC03 from inerts
in a classifying centrifuge, or the air classification of this material,
is a determining factor in the efficiency of the process.
A decision on recalcination of lime is essentially an economic study
considering the cost of lime, the capital costs necessary to achieve the
recalcination, the additional operating costs necessary to achieve the
recalcination, and the costs of disposing of the incinerated ash. The
latter item is one which is very often not considered in such an econ-
omic analysis, but the reuse of 65% to 85% of the lime can reduce
significantly the volume of ash generated from the incineration process,
and, if the costs associated with this final ash disposal are signifi-
cant, it can have a marked effect upon the total economic picture.
In the solids handling report, analyses of ten separate programs were
made. The recommendation to the Authority was the adoption of a program,
the flow diagram for which is contained in Figure 38. The initial recom-
mendation included incineration of primary sludges and the secondary-
tertiary sludges in dual train incinerators. It also included provision
for recalcination of the primary lime sludges, and utilization of two
stage centrification. Reference to Figure 38 will indicate that the
primary lime sludges would be proposed to be thickened in a gravity
thickener, and would then be passed through the first stage centrifuge.
The cake from the first stage centrifuge would be directed to the mul-
tiple hearth incinerator, which would be heated to a recalcining temper-
ature. The material from the incineration of the primary sludge would
be sent to a classifier, where the recovered lime would be conveyed to
the bulk lime storage silo, and the rejects from the ash classifier
would be combined with the ash from the secondary furnace and hauled to
a landfill. The centrate from the first stage centrification of the
primary sludge would be submitted to a second stage centrifuge for
dewatering, and the cake would be discharged directly to the top part of
the WAS-tertiary multiple hearth furnace.
The WAS-tertirary sludges, being much harder to dewater, would be sub-
jected to flotation or mechanical thickening, then heat treatment and
decantation, and finally centrification and incineration.
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WT-LEWT i
DISPOSAL
•C-
00
BULK
LIME
STORAGE
ASH
Figure 38 . Diagram of Recommended Sludge Disposal System - 1973
-------
This recommendation to the Authority was deemed to be the most suitable,
long-range method of providing for complete solids handling, utilizing
the most efficient process combinations for each type of sludge. The
Authority, however, deemed that recalcination of the lime could result
in operating problems, and further, felt that the utilization of heat
treatment in the secondary-tertiary sludge processing would create objec-
tionable odors and other operating problems, and they indicated their
desire to adopt a different program.
The program which the Authority finally selected is shown in flow dia-
gram form in Figure 39. This program utilizes the separate treatment of
the primary and the secondary-tertiary sludges, and eliminates the recal-
cination step, as well as the heat treatment of the secondary-tertiary
sludges. A summary of the solids handling units required for this
Program VII is contained in Table 45.
TABLE 45. SUMMARY OF SOLIDS HANDLING UNITS, PROGRAM VII
1 - Gravity Thickener 65' 0 x 10' swd (19.8 m 0 x 3 m swd)
2 - Centrifuges 10' x 12' (3 m x 3.65 m)
2 - Multiple-Hearth Furnaces 1 - 22.25' x 10 Hearth (6.8 m)
1 - 16.75' x 7 Hearth (5.1 m)
1 - Flotation Unit 25' 0 x 10' swd (7.6 m 0 x 3 m swd)
1 - Blend-Mix Unit 25' 0 x 10' swd (7.6 m 0 x 3 m swd)
The Authority decided that, in lieu of providing two separate multiple
hearth furnaces with different diameters and hearth arrangements, two
furnaces would be provided, each of identical size, and each of the larg-
est capacity required. This will be done in order that a malfunction of
one of the furnaces will permit utilization of the remaining furnace for
combined incineration of the total sludge on an emergency or interim
basis.
The solids dewatering facilities investigated were based upon a 12-hour/
day, 5 days/week operation, plus an additional 35-hour/week of start-up
and take-down time, including maintenance, for a total operation of
approximately 95-hours/week at 8.0 mgd flow. This appears to be an
optimum balance between capital costs in sizing units, and operating
costs. This would involve, at 8.0 mgd, essentially a two shift per day
operation, and the facility would have an ultimate capacity of 16.0 mgd,
with 120-hours/week of actual burning time, plus 35-hours/week of start-
up and shut-down. In Figure 40 a graph is presented indicating total
annual costs versus million gallons per day treated. This figure is
presented as a means of indicating the requirements for operation at
various flows. For instance, up to 5.2 mgd would require only one shift
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EFFLUENT
Ln
O
FLOTATION OR
MECHANICAL THICKENING
BLEND-MIX
STORAGE
c
CENTRIFUGE
1 MULTIPLE
•^1 HEARTH
FURNACE
Figure 39. Diagram of Sludge Disposal System Under Design-1974
-------
300
O
o
O
H
CO
o
PLANT FLOW - MGD
Figure 40. Annual Cost of Sludge Processing
-------
operation each day, and two shifts would be required between approximately
5.3 and 10.7 mgd.
Thus, the proposed solids handling expansion can accommodate flows in
excess of 10.0 mgd with a two shift operation, which would appear to be
the most optimum balance between capital and operating costs. With the
Federal participation of the United States at a 75% level of construc-
tion costs, the desirability of providing sufficient future capacity in
this expansion for the ultimate foreseeable development of the entire
drainage area, appears warranted. Once the solids handling capacity is
provided, hydraulic expansions can take place at a pace required by
growth in the area at a greatly reduced cost per additional capacity
provided.
HYDRAULIC EXPANSION
The future hydraulic expansion of the existing Hatfield Township advanced
waste treatment facility is subject to the finalization of the regional
wastewater treatment program now being discussed among the various com-
munities and the State government. If all of the communities tributary
to the advanced waste treatment facility are included, an expansion
program of an additional 8.5 mgd (32,172 m^/day) to a total capacity of
12.5 mgd will be required. It appears more likely, however, that the
required expansion will more nearly approximate 3.65 mgd (13,815 m3/day)
to a total hydraulic capacity of about 7.5 mgd (28,388 m3/day)-
Based upon the expansion of the facility to approximately 7.5 mgd, it is
anticipated that the total program will include the addition of the
following units.
1. Screening and grit removal ahead of the main raw sewage pumping
stations.
2. The addition of a third raw sewage pump in Pump Station No. 2.
3. Possible additional flow equalization, dependent upon the
success of removing inflow/infiltration from all of the col-
lection systems utilizing the facility.
4. Duplicate additional primary clari-flocculators.
5. Additional primary sludge pumping facilities.
6. Duplicate additional aeration tanks.
7. Duplicate additional secondary clarifiers.
8. Additional back-wash storage facilities, and back-wash pumps.
9. Additional chlorination facilities.
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In addition to these units, it is anticipated that the expansion program
would include the installation of an automated biological control system
to control the mixed liquor solids content in the aeration basins and
to control the return of activated sludge and the wasting of activated
sludge. It is also anticipated that this program would include the
addition of more sophisticated laboratory equipment, probably including
a Technicon analyzer, and the addition of an electrical consol to cen-
tralize, at the very least, a monitoring operation in a new administrative
and office building.
Consideration is being given to the possibility of refining the operation
by the utilization of more automatic controls, and possibly computers, in
an effort to reduce the labor costs and provide more precise control of
the process. This, however, appears to be a situation that will not prac-
tically occur within this next expansion program. At a recent I.A.W.P.R.
workshop, held in London in September 1974, on the very subject of auto-
mation of wastewater treatment facilities, it was evident that there are
significant problems in the total automation of a facility, occasioned
primarily by the lack of either accurate enough, or in some cases, any
sensor for a particular controlling function. The present thinking with
respect to expansion of the Hatfield Township advanced waste treatment
facility is to provide in the next expansion as much automation as is
practical.
ADDITIONAL EFFLUENT REQUIREMENTS
The current limiting effluent quality characteristics, as originally pub-
lished by the State government in 1967, require a degree of treatment in
excess of 99% efficiency. The State government has now imposed a limiting
criteria on the nitrogen component discharged into the receiving stream.
It is a maximum total nitrogen content of 8.0 mg/1.
In the planning for the next hydraulic expansion, emphasis will be placed
on the nitrogen removal with further investigation of the ability to
nitrify in the aeration basins, with the tentative thought that denitri-
fication would be accomplished by introducing a carbon source into the
influent to the tertiary pressure filter system. Work has been done in
other areas on denitrification by the addition of methanol to the flow
stream, just ahead of the filtration step, and from the data reported
thus-far, it appears that this may be a suitable means of achieving total
denitrification. The ^utilization of such a step would fit the Hatfield
flowsheet with very minor modifications.
One major factor to be reckoned with is the high cost of methanol
(CH30H) at $0.37/gallon (August 1974). Various other alternatives are
being investigated, none of which are completely satisfactory from an
economic standpoint.
Beyond the addition of a limiting nitrogen effluent criteria, there does
not appear to be on the horizon any other effluent limitation which might
be imposed short of the prohibition of any discharge at all directly to
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the surface waters. This is quite commonly referred to as "zero" dis-
charge, and there is considerable discussion being generated as to the
merits of this program. Certainly, the characteristics of the effluent
being produced currently at the Hatfield Township waste treatment facility
are more than sufficient for the utilization of this effluent for indus-
trial process purposes, for cooling towers, and, in areas where public
water supplies are not available, this water could be utilized in a
separate fire protection system.
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SECTION XI
CRITICAL EVALUATION OF HATFIELD TOWNSHIP
ADVANCED WASTE TREATMENT FACILITY
GENERAL
The Hatfield Township treatment facility has been operational for four-
teen months. The initial operation of the plant benefitted by the
existence of an Environmental Protection Agency sponsored Demonstration
Grant, which was intended to provide funds for the analysis of opera-
tions to meet certain design parameters. One of the fringe benefits of
the grant was the presence at the plant of an engineer, who was able to
aid in operation and at the same time, critique the design of the plant.
As is always the case, in addition to this critique by the engineer,
operations personnel have offered many suggestions and criticisms, which
would enhance the operational practices. These latter suggestions most
often pertain to operator ease, and operator safety, but in some cases,
provided insight into process modifications which would be beneficial.
Finally, the consulting engineer recognized a number of situations that
required, or still require, modification to acheive an optimum blend
of excellent operation, coupled with maximum operator convenience and
safety, and reasonable capital and operating costs.
PRELIMINARY TREATMENT
All flows entering the Hatfield Township facility are comminuted. The
liquid passes through moving screens, which chop up the rags and other
large solid matter to prevent clogging of the pumps. There is no grit
removal, since there was no evidence of grit prior to the design of the
expanded facility.
One for the first tasks accomplished by the general contractor in the
1970 construction project, was the elimination of plant by-passes. In
the months that followed, it became evident that there was a good deal
of infiltration into the collection system during periods of heavy rain-
fall. Flows which previously had been by-passed into the Neshaminy Creek
were allowed to enter the plant for treatment. These peak flows also
tended to scour the sewer lines and carried with them large volumes of
grit. The grit eventually settled-out on the floor of the surge storage
tanks, and periodically must be removed by plant operations personnel.
Even when the comminutors are working, fibrous material seems to extrude
itself through the comminution devices. Chopped up rags then mix with
this fiber material and reweave themselves into mats, resulting in a
maintenance problem. These mats serve as a point for solids to collect,
155
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and will periodically clog pipes and pumps. It is proposed, in the
future, to use complete initial screening to fully eliminate grit and
rags from the process flow stream.
FLOW EQUALIZATION BASINS
The tank configuration of the flow equalization basins at the Hatfield
facility are rectangular. Solids entering the vessel tend to agglomerate
in the corners. Large volumes of organic material in the solids even-
tually become putrescible and lead to process, as well as esthetic,
problems. During extremely low flow conditions, the dissolved oxygen in
the flow equalization basins drops off considerably. The mechanical
mixers utilized do not have the capability of preventing these problems.
It is proposed to resolve the problems of the flow equalization basins
by the addition of air mixing, which should not only keep the solids in
suspension, but should also eliminate problems of septicity. The units
at Hatfield, supplied with air and protected by adequate grit removal
and screening, should not experience the difficulties presently faced.
As a result of the Hatfield Township flow equalization problems, a cir-
cular flow equalization basin with three compartments, each equipped with
a floating aerator would be recommended. This method appears to be far
more satisfactory than that utilized in the Hatfield facility. Unfor-
tunately, future additional equalization basins at Hatfield will, if
required, probably necessitate expansion by construction of additional
rectangular basins, due to the space available in the area where such
construction would be required. However - adequate mixing and dissolved
oxygen would be provided.
CHEMICAL FEEDS
One of the problems, not anticipated at the Hatfield facility, was the
volume of inert material in the pebble grade lime. At least 2% of the
pebble lime is inert. As a result, for every ton of lime consumed,
there is produced at least forty pounds of gritty material. Since the
lime slakers are located in the basement of the building, this means
that periodically operators must manually haul the grit out of the base-
ment for disposal on landfill. This is a laborious task, and consumes
many man-hours of the operators' time. The slaked lime is contained in
a slurry tank and must be pumped up to the volumetric lime feeder. The
inert material creates a good deal of wear on the slurry pumps, and has
a tendency to deposit itself in the valves and in the piping. This has
led to a maintenance problem, in that periodically the slurry tank,
pumps, and lines must be cleaned of this material.
The problem of wear and tear has been solved by the use of cast iron
pump impellers, water seals on the pumps and a regular maintenance program,
In addition, an industrial elevator or electric hoist will be utilized to
bring the collected inerts to the surface.
156
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It is proposed that, in new plants, the lime feed equipment will be
located above the point of introduction. The slurry type slaking system
operates fairly well, and will operate much better with the solids prob-
lem eliminated. Ball valves will be eliminated from the lime slurry
piping system to prevent plugging up with inert material.
The alum fed into the tertiary system is dry, granular, aluminum sulfate.
It is packed in 100-pound (45.4 kg) bags, and the unexpectedly large
amounts consumed result in the operators having to carry a 1,200-1,500
pound (544.8-681 kg) daily supply of alum up a flight of stairs. This
has met with the dissatisfaction of operations personnel, and has become
a subject of grievance with the labor union. It is proposed to convert
to a liquid alum feed system. Liquid alum is less expensive on a dry-
weight basis, and the cost savings in chemicals alone are expected to
amortize the tankage and piping required in less than three years.
In the tertiary system, alum can be fed to the flash mixer, or directly
to the filter influent clear well. Polymer can be fed to the tertiary
flocculator, or also the the filter influent clear well. This arrange-
ment does not give the operations personnel the flexibility to feed
polymer and alum prior to the tertiary filters in the best possible
manner. Any floe that may form may be destroyed by its passage through
the high rpm centrifugal pumps feeding the filters. Plant personnel
are in the process of relocating these feed points downstream of the
filter influent pumps.
In a wastewater treatment facility, it sometimes becomes necessary to
feed chlorine in order to reduce septic conditions. Chlorine feed lines
should be included into the gravity thickener, the head-box of the aera-
tion tank, and to the secondary clarifiers.
AUTOMATION
The Hatfield facility was designed utilizing probe type pH sensing ele-
ments. These have proven to be a major operational problem. The pH
probes in the surge storage tanks were never installed because, period-
ically, they would be out in the air and they would be impossible to
maintain. The pH probes in the flocculation zone of the clari-floccu-
lator, which serves as the major point of control, have a tendency to
coat up with calcium carbonate scale. This scale increases the resis-
tence across the pro.be, calling for more lime to be fed. With more lime
being fed, more scale is formed, and eventually the pH of the primary
effluent increases beyond the limits of biological secondary treatment.
As a result, the pH control of lime feed has been converted to a manual
basis. At the same time, flow-through probes are being experimented
with, and the initial response is an extremely good one. Indications
are that, except for plugging of the feed line into the pH probes, the
flow-through probe requires minimal maintenance and is fairly consistent
with manual laboratory testing.
The flow through probes have been in operation for over six months, and
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they are checked at least twice per week against a standardized laboratory
pH meter. The flow-through probes correlate very well with the lab meter
(i? 0.2 pH units). There is, however, a need to clean the inlet hose of
accumulated solids to prevent plugging. This is done at least once per
day.
There are various types of flow measuring devices in use in the Hatfield
Township facility. There are magnetic flow meters which send signals to
the Red Valves. One of the problems with these meters is that it is
extremely difficult to calibrate them. Raw sewage into one pump station
is measured by a Parshall flume, and into the other station, by the use
of a flow nozzle. Both units depend upon a float-type action to sense
a level in the measuring device. During high flow rates, the flows
exceed the limits of these devices, and the net result is loss of accu-
rate flow measurement. The flow of all sludges is measured by the use
of Venturi type meters. The centers in the Venturi meters tend to plug
up with solids, and as a result, false readings are obtained. Grit
removal, and adequate screening should resolve this problem.
One of the most basic methods of monitoring a plant is that of measuring
flow. The heterogeneous nature of sewage and sewage sludges has pointed
out the problems inherent with operation of conventional flow meters.
Until such time as something as basic as flow measurement can be resolved,
additional automation of treatment facilities is questionable.
AUTOMATIC SAMPLERS
The data used in the design of the 1970 facility was based upon manually
composited grab samples. The expanded facility includes the utilization
of composite samplers throughout the plant. While there are many bene-
fits to be derived from the use of automatic, refrigerated, composite
samplers, they too result in a maintenance problem. The lack of main-
tenance of a composit sampler can result in more misleading information
than obtained from a grab sample.
Automatic samplers are to be found in the Hatfield Township facility, as
indicated in Table 46.
TABLE 46. AUTOMATIC SAMPLER LOCATIONS
Raw Wastewater Secondary Effluent
Surge Storage Tank Filtered Effluent
Primary Effluent Final Effluent
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PUMPS
The Hatfield Township facility utilizes centrifugal pumps throughout.
One of the problems, not yet investigated is the potential problem of
degradation of the sludges by shearing through the high-speed centri-
fugal machine.
The design of the Hatfield Township facility requires the use of portable
pumps for dewatering the majority of treatment vessels. Where possible,
it is recommended that all tanks be capable of draining by gravity. This
will facilitate flushing operations. The use of large gate valves with
gear reducers results in a good deal of manual effort in opening or
closing these valves. The cost of motorizing these valves was found to
be prohibitive on the initial design of the project. Plant operations
personnel are looking into the purchase of a portable electric valve
operator. Ideally, all of the valves should have been equipped with
electric operators, controllable from a central control point.
It is presently impossible to by-pass the tertiary filters. During
extremely high flow conditions, the solids carry-over from the secondary
and tertiary cycle tends to plug up the filters, resulting in continuous
back-wash and more recycle. Eventually, the plant operates on just
treating its own recycle. To eliminate this problem would require the
inclusion of a by-pass around the tertiary filters in the plant flow
scheme. A by-pass was eliminated during the construction plan review by
Federal Regulatory Agency personnel.
Where there are no prohibitions on in-plant by-passes around unit processes,
their availability should be encouraged.
PROCESS OBSERVATIONS
The benefit of flow equalization basins has been proven by the operation
at the Hatfield Township facility. The sudden surges from industrial
loads, filter back-washes within the plant itself, or heavy rain which
normally washes out the biological reactor, or upsets the chemical treat-
ment processes in the facility is relieved. The flow equalization basins
tend to dampen the effect of these surges and give the operators enough
time to compensate for any problems incurred. The actual location of
these units, upstream of the primary- helps provide steady state condi-
tion throughout the plant. The large amount of recycle within the plant
however, results in a considerable expenditure of chemical to treat the
recycled waste through the facility. In order to meet effluent standards,
however, this is a must.
The plant is equipped with two aeration tanks, 50' x 50' x 15'. These
provide 3.75-hours of total detention, enough detention for bio-oxidation,
but not enough for complete oxidation of the ammonia form nitrogen. Any
additional expansion will include enough aeration capacity for the com-
pletion of nitrification.
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The Hatfield facility utilizes pressure filters, furnished with a mixed-
media. Since the majority of the suspended solids have been removed by
clarification in the tertiary tube-type clarifiers, the necessity of
this mixed-media has not been unequivocally proven in operations to date.
The use of lime in the primary treatment vessels tends to break down the
fatty acid material and generally forms a scum of calcium sterate pre-
cipitate, which collects within the flocculation basin, which is some-
times difficult to remove without manually hosing it out. Scum is
gathered in collectors in the primary and secondary treatment vessels
and pumped to the thickener. Any scum floating on the surface of the
thickener is gathered in a collector, and pumped to the vacuum filter
and then to incineration. During periods of nitrification, a good deal
of the aeration sludge tends to float in the secondary clarifiers, and
is extremely difficult to remove except by allowing it to wash out into
the tertiary units, where it is clarified out. Provisions should be
made to pump the secondary sludge back to the head-box of the aeration
basin in order to maintain a nitrifying capability.
The Hatfield Township Municipal Authority advanced waste treatment facility
was a prototype. As such, it serves as a basis to build upon. A firm
knowledge of the problems encountered in the plant are as important as
the knowleddge of those units of operation and processes which operate
adequately. It is hoped that the data and discussions presented in this
report will enable future projects to benefit from the deficiencies
observed during the development of this project, and to benefit from the
demonstrated success of the total operation.
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SECTION XII
REFERENCES
1. Albertson, Orris E., Marketing Manager, Water Management Systems,
Dorr-Oliver, Inc., Private Communication dated January 19, 1968.
2. Bunch, Dr. R. L., Biological Treatment Research Activites, Cincin-
nati Water Research Laboratory, FWPCE-USDI, "Phosphorous Removal in
Conventional Treatment", Chicago Seminar on Phosphorous Removal,
May 1-2, 1968.
3. Dean, Dr. R. B., Chief, Ultimate Disposal Research Activities, Cin-
cinnati Water Research Laboratory, FWPCA-USDI; "Forms and Measurements
of Phosphorous", Chicago Seminar on Phosphorous Removal, May 1-2,
1968.
4. Mackenthum, et.al,JWPCF, Vol. 40, No. 2, Part 2, February '68, R73-
R81, "Nutrients and Algae in Lake Sebasticook, Maine".
5. Sawyer, Clair N., JWPCF, Vol. 40, No. 3, Part 1, May '68, 363-370,
"The Need for Nutrient Control".
6. Earth & Ettinger, JWPCF, Vol. 39, No. 8, August '67, 1362-1368,
"Mineral Controlled Phosphorous Removal in the Activated Sludge
Process", and Paper presented at Chicago Seminar on Phosphorous
Removal, May 1-2, 1968.
7. Levin & Shapiro, JWPCF, Vol. 37, No. 6, June '65, 800-821, "Metabo-
lic Uptake of Phosphorous by Waste Water Organisms".
8. Vacker, Connell & Wells, JWPCF, Vol. 39, No. 5, May '67, 750-771,
"Phosphate Removal Through Municipal Waste Water Treatment at San
Antonio, Texas".
9. Brunner, Dr. Carl A., Chemical Engineer, Project Analysis Activities,
Cincinnati Water Research Laboratory, FWPCA-USDI, "Phosphorous Re-
moval by Tertiary Treatment with Lime and Alum", Chicago Seminar on
Phosphorous, May 1-2, 1968.
10. Gulp, R. L. & Roderick, JWPCF, Vol. 38, No. 2, February '66, 147-155,
"The Lake Tahoe Water Reclamation Project".
11. Slechta & Gulp, G. L., JWPCF, Vol. 39, No. 5, May '67, 787-814, "Water
Reclamation Studies at the South Tahoe Public Utility District".
161
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12. Buzzell & Sawyer, JWPCF, Vol. 39, No. 10, Part 2, October '67,
R16-R24, "Removal of Algal Nutrients from Raw Waste Water With
Lime".
13. Albertson & Sherwood, Water Management Division, Dorr-Oliver, Inc.
"Phosphate Extraction Process", Paper released to the technical
press, September 12, 1967.
14. Cohen, J. M., Chief, Physical & Chemical Research Activities, Cin-
cinnati Water Research Laboratory, FWPCA-USLi, "Alternative Methods
of Phosphorous Removal", Chicago Seminar on Phosphorous Removal,
May 1-2, 1968.
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SECTION XIII
GENERAL BIBLIOGRAPHY
Albertson, 0. E., "Systems for Phosphate & Nitrogen Removal," Presented
at 41st Annual Conference of Water Pollution Control Association of
Pennsylvania, University Park, Pennsylvania, August 6, 1969.
American Public Health Association, American Water Works Association and
Water Pollution Control Federation. Standard Methods for the Exa-
mination of Water and Wastewater. llth Ed. New York, N.Y., American
Public Health Association, Inc. 1960.
Babbitt, H. E. and Banmann, E. R., Sewerage and Sewage Treatment. 8th Ed.
New York, N.Y., John Wiley and Sons, Inc. 1958.
Earth, E. F., et.al., "Chemical-Biological Control of Nitrogen and Phos-
Phorus in Wastewater Effluent," J. Water Pollution Control Federation,
Vol. 40, 2040. 1968.
Earth E. F. and Dean, R. B., "Nitrogen Removal from Wastewaters State-
ment of the Problem," Presented at Session Two, Advanced Waste
Treatment and Water Reuse Symposium, Adolphus Hotel, Dallas, Texas,
January 12-14, 1971.
Downing, A. L. and Hopwood, A. P., "Some Observations on the Kinetics of
Nitrifying Activated-Sludge Plants," Schweizerische Zeitschrift for
Hydrology, Vol. XXVI, Fasc. 2,271-288. 1964.
McKinney, R. E., Microbology for Sanitary Engineers. 1st Ed. New York, N.Y.,
McGraw-Hill Book Company, Inc. 1962.
Wild, Jr., J. E., Sawyer, C. N. and McMahon, Thos. C., "Factors Affecting
Nitrification Kinetics," Presented at 43rd Annual Conference of the
WPCF, Boston, Massachusetts, October 4-9, 1970.
163
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SECTION XIV
APPENDICES
Page
A. Basis of Design And Component Calculations 165
B. Method For Total Phosphorus Analysis 180
C. Industrial Surcharge Program 188
D. Analytical Data 194
E. Hatfield Township Municipal Authority Review Of
Present Design For Ability To Achieve Additional
Nitrogenous BOD Removal 218
F. Generation Of Sludges 222
164
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APPENDIX A
BASIS OF DESIGN
AND
COMPONENT CALCULATIONS
1970 AWT FACILITY
1. Basis of Design
Average 24 Hour Domestic Sewage Flow 2,850,000 GPD (10,787 M3/D)
Allowance for Industrial Flows -
Present & Future 750,000 GPD (2,839 M3/D)
Design Average Hour Flow = Q = 3,600,000 GPD (13,626 M3/D)
or 2,500 GPM (9,462 L/M)
16 Hour Rate of Flow = 1.5Q = 5,400,000 GPD (20,439 M3/D)
or 3,750 GPM (14,194 L/M)
Peak Rate of Flow = 2.0Q = 7,200,000 GPD (27,252 M3/D)
or 5,000 GPM (18,925 L/M)
Equivalent Design Population @ 90 GPC (342 L/C)
Domestic 31,700 Persons
Industrial 8,300 Persons
BOD Loading - Domestic 0.17 Lb/Capita/Day* (0.077 Kg/D/C)
Suspended Solids Loading - Domestic 0.17 Lb/Capita/Day* (0.077 Kg/D/C)
Total BOD 7,050 Lb/Day** (3,204 Kg/D)
Total Suspended Solids 7,050 Lb/Day** (3,204 Kg/D)
* Equivalent to 226 mg/1. Present BOD average 192 mg/1. Present
suspended solids average 178 mg/1.
** Future Industrial flows anticipated to have BOD and suspended solids
loadings equivalent to 0.20 Lb/Equiv. Capita/Day (0.091 Kg/D/C)
2. Plant Components
A. Comminutors
(1) Number of Units - Two (One Existing)
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(2) Type, Size and Capacity
Oscillating type, 15" size, 0.30 mgd to 3.5 mgd
capacity.
(3) Auxiliary Screen - None
Second comminutor to be located in existing hand-
cleaned bar screen location.
B. Flash Mixing - Primary
(1) Number of Units - Two
(2) Main Dimensions
Mixer No. 1 (Bottom Feed) - 5'-0" x 5'-0" x 7'-8" SWD
Mixer No. 2 (Bottom Feed) - 9'-0" x 9'-0" x H'-4" SWD
(3) Capacity
Mixer No. 1 - 191.8 CF = 1,438 Gallons
Mixer No. 2 - 917.7 CF = 6,883 Gallons
(4) Detention
Mixer No. 1 - @ Q = 2^500 GPM* = °'58 Minutes
/: Q Q O pa "I
Mixer No. 2 - @ 0.5 Q = 1*250 GPM* = 5'5 Mlnutes
NOTE: Lime added to 50% recirculated sludge in Mixer No.
2, then mixed with raw sewage in Mixer No. 1.
C. Clarifier - Flocculators
(1) Number of Units - Two
(2) Main Dimensions
Each: 60'-0" Diameter x 10?-0" SWD
(3) Capacity of Units
2 x 2,825 SF x 10 Ft. = 56,500 Cu. Ft. = 423,750
Gallons
166
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(4) Detention Period at Q
423.750 Gal.
—
2 500 GPM ".5 Minutes = 2.82 Hours
(5) Surface Settling Rate at Q
2,600,000 GPP
5,650 SF = 637 Gal/SF/Day
(6) Effluent Weir Overflow Rate at Q
(7) Flocculation
(a) Main Dimensions
Each: 31 '-0" Diameter x 6 '-9" SWD
(b) Capacity of Units
2 x 755 SF x 6.75 Ft. = 10,192 Cu. Ft. = 76,440
Gallons
(c) Detention
76,440 Gal.
2,500 GPM = 30'6 Minutes
(8) Sludge Recirculation
50% Maximum, 1,250 GPM
D. Aeration Tanks
(1) Number of Units - Two (One Existing)
(2) Main Dimensions
Each: 50'-0" x 50'-0" x 15'-0" SWD
(3) Capacity of Units
2 x 50' x 50' x 15' = 75,000 Cu. Ft. = 562.500 Gal.
= 4.69 (106) Lb.
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(4) Detention Period at Average Flow (Not Including Return
Sludge)
562,500 Gal.
2 500 GPM = ^-* Minutes = 3.75 Hours
(5) Loading of Tanks
BOD to Aerators: - 7,050 Lb. x 0.40 = 2,820 Lb/Day
MLSS: - 2,820 Lb/Day
0.35 Lb. BOD/Lb. MLSS ~ b'050 Lb> MLSS
MLSS Concentration: - 8,050 Lb. MLSS ,_,.
4^69 (106) Lb. Vol. = 1716
(6) Type of Aeration Facilities
(a) Classification
Combination Aerators, providing mechanical mixing
and surface transfer of oxygen as well as sparged
air diffusion.
(b) Number of Units - Two (One Each Tank)
(c) Capacity Required
0.80 Lb. 02/Lb. BOD x 2,820 Lb. BOD = 2,260 Lb/Day 02
=94.2 Lb/Hour 02
Provide Total 02 Required in Each Basin
Assume 2 Lb. 02 Transfer per HP Hour
HP Required, Each Basin = 94.2 Lb/Hour =
2 Lb/Hr/HP
47.1 HP Use 50 HP Each Basin
E. Secondary Clarifiers
(1) Number of Units - Two
(2) Main Dimensions
Each: 55'-0" Diameter x 12'-0" SWD
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(3) Capacity of Units
2 x 2,376 SF x 12 Ft. = 57,024 Cu. Ft. = 427,680 Gal.
(4) Detention Period at Q (Not Including Return Sludge)
427,680 Gal.
2 500 GPM - = 171'1 Minutes =2.85 Hours
(5) Surface Settling Rate at Q
3,600,000 GPP _,_„ , ,
\ 7'52 SF - = 758 Gal/SF/Day
(6) Effluent Weir Overflow Rate
3.600,000 GPP , ,
2 x ^ LF - = 10,405 Gal/LF/Pay
F. Flash Mixing - Tertiary
(1) Number of Units - Two
(2) Main Dimensions
Each: 9 '-6" x 8'-0" x 9 '-6" SWD
(3) Capacity of Units
Each: 722 Cu. Ft. = 5,415 Gallons
(4) Detention - Each
* '
1250 GPM = 4'33 Minutes @ 1/2 Q Each
2^00 GPM' =2. 17 Minutes @Q Each
*
G. Flocculation
(1) Number of Units - Two
(2) Main Dimensions
Each: 26'-0" x 12'-0" x 12'-0" SWD
(3) Capacity of Units
Each: 3,744 Cu. Ft. = 28,080 Gallons
169
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(4) Detention - Each
= 22'5 Minutes @ 1/2 Q Each
H. Tube Settling - Tertiary
(1) Number of Units - Two
(2) Main Dimensions
Each: 67'-0" x 16'-0" x 10'-6" SWD
(3) Capacity of Units
Each: 11,256 Cu. Ft. = 84,420 Gallons
(4) Detention - Each
' = 67'5 Minutes @ 1/2 Q Each
' " 33.8 Minutes @ Q Each
(5) Surface Settling Rate @ Q
Tube - Module Design - Angle tube - settling modules,
2" Square, inclined at 60° to the horizontal, 24" long.
Tube Overflow Rate: -1.9 GPM/Ft.
Equivalent Tube - Settling Overflow Rate - 240 Gal/SF/Day
(6) Effluent Weir Overflow Rate
I. Mixed-Media Filters - Tertiary
(1) Number of Units - Three
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(2) Type
Pressure Filters, Mixed-Media
(3) Main Dimensions
Each: 28'-0" L x lO'-O" Diameter
(4) Filter Area
Each: 287 Sq. Ft.
(5) Filter Rate - Each
833 GPM
287 Sq. Ft. = 2'9 GPM/Scl- Ft- @ 1/3 Q
. Ft. @3/4Q
Maximum Filter Rate: -7.5 GOM/Sq. Ft.
Maximum Flow/Filter = 2,200 GPM =9.5 MGD*
*Gross, Not including down time for backwash.
(6) Backwash Flow Rate
14.6 GPM/Sq. Ft.
(7) Surface Wash Flow Rate
0.7 GPM/Sq. Ft.
J. Chlorine Contact Tanks
(1) Number of Units - Four (All Existing)
(2) Main Dimensions
Existing C12 Tanks - 2 @ 20 '-0" long x 13 '-0" wide
x 6'-6" SWD
Existing Sec. Clarifiers - 2 @ 28 '-0" diameter x 5 '-6'
SWD
171
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(3) Capacity of Units
Existing C12 Tanks = 2,800 CF = 21,000 Gal.
Existing Sec. Clarifiers = 6.776 CF = 50,820 Gal.
9,576 CF = 71,820 Gal.
(4) Contact Time @ Maximum Pumping Rate
71.820 Gal. ,, . „. .
5,000 GPM = l^Minutes
K. Chlorination
(1) Number of Units - Two
(2) Capacity
Each: 100 Lb/Day, Total 200 Lb/Day
(3) Capacity Required
6 mg/1 @ Q Ave. = 6 mg/1 x 8.34 Lb/MG/mg/1 x 3.6 MGD =
180 Lb/Day
NOTE: Upon completion of Phase II, dosage required
should be 4-5 mg/1 at Q Ave.
L. Sludge Thickener
(1) Number of Units - One (Abandon existing unit)
(2) Main Dimensions
40'-0" diameter x 10T0" SWD
(3) Capacity of Unit
1,260 SF x 10 Ft. = 12,600 CF = 94,500 Gallons
(4) Estimated Sludge Volume
Primary - 7.050 Lb. SS/Day x 0.85 Removal = 6,000 Lb/D
Lime - 6,000 Lb/Day x 0.80 Recovery = 4,800 Lb/D
WAS - 160 mg/1 BOD 3.6(10)6Gal 8.34 Lb
106 Lbx Day x Gal
0.45 Lb PS
X Lb BOD = 2.160 Lb/D
Total Sludge Volume 12,960 Lb/D
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(5) Thickener Flow
Feed Concentration = 3,500 mg/1
Total Solids = 12,960 Lb/Day
12,960 Lb/D . ,-.
3 500 (10b) = 3'7 (1° ) Lb> Liquid/Day = 445,000
Gal/Day = 310 GPM
(6) Overflow
@ 700 GPD/Ft.2 Overflow Rate, Inflow =
700 GPD/Ft.2 x 1,260 SF = 882,500 GPD = 610 GPM
Provide 300 GPM Dilution Water
M. Sludge Dewatering
(1) Classification - Vacuum Filters
(2) Number of Units - Two (Existing)
(3) Main Dimensions
Each: 4'-0" diameter x 4'-0" long
(4) Capacity
50 Sq. Ft., Total 100 Sq. Ft.
(5) Filtering Rate
4.5 Lb. DS/SF/Hour, Total = 450 Lb. DS/Hour
(6) Hours Operation/Week
From E. above - Total Lb. DS = 12,960 Lb/Day
12,960 Lb/Day x 7 D/Wk. = 90,720 Lb. DS/Wk.
90,720 Lb. DS/Wk. on, , „ ,T7 .
. c!. T,—=^TTS = 201.6 Hours/Week
450 Lb. DS/Hour
NOTE: At such time as solids loading approaches 140
Hrs./Wk. operation, an additional vacuum filter
will be installed.
173
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N, Sludge Incineration
(1) Number of Units - One (Existing)
(2) Type - Multiple Hearth Furnace
(3) Main Dimensions
10'-9" diameter x 17'-6" high
(4) Capacity
1,500 Lb. Filtered Sludge Cake/Hour @ 45% Volatile
Content
(5) Hours Operation/Week
From E. above - Total Lb. DS = 12,960 Lb/Day = 90,720
Lb/Week
@ Filtered Cake Moisture Content of 75%, amount of
Sludge Lb. Cake/Week
Cake/Week = 90.?20^Lb/Wk = 362,880 Lb. Cake/Week
362,880 Lb. Cake/Week = 241.9 Hours/Week
1,500 Lb. Cake/Hour
NOTE: At such time as furnace operations approaches 140
hours/week, provision will be made to increase
furnace capacity. Present furnace operations ap-
proximately 24 Hours/Week.
0. Pumping
(1) Raw Sewage Pumps
(a) Number - Two
(b) Type
Vertical, extended, open-shaft, dry-pit, non-clog,
constant speed.
(c) Capacity, Each - 3,500 GPM @ 51.75' TDH
(2) Activated Sludge Return Pumps
(a) Number - Three
174
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(b) Type
Horizontal, ball-bearing, non-clog, variable
speed.
(c) Capacities
Pump No. 1 - 625 to 2,500 GPM @ 31.3' TDK
Pump No. 2 - 625 to 2,500 GPM @ 31.3' TDH
Pump No. 3-0 to 625 GPM @ 32.3' TDH
(3) Waste Activated Sludge Pumps
(a) Number - Two
(b) Type
Horizontal, ballbearing, non-clog, variable
speed.
(c) Capacity, Each - 50 to 100 GPM @ 30.8' TDH
(4) Waste Primary Sludge Pumps
(a) Number - Two
(b) Type
Horizontal ball-bearing, non-clog, variable
speed.
(c) Capacity, Each - 160 to 320 GPM @ 42' TDH
(5) Primary Sludge Recirculation Pumps
(a) Number - Two
(b) Type
Horizontal ball-bearing, non-clog, variable
speed.
(c) Capacity, Each - 625 to 1,250 GPM @ 22' TDH
(6) Filter Influent Pumps (Secondary Clarifier Effluent Pumps)
(a) Number - Three
175
-------
(b) Type
Horizontal ball-bearing, non-clog, variable
speed.
(c) Capacity, Each - 1,100 to 2,200 GPM @ 49.4' TDH
(7) Dilution Water Pumps
(a) Number - Two
(b) Type
Horizontal ball-bearing, non-clog, variable
speed.
(c) Capacity, Each 150 to 300 GPM @ 43.4' TDH
(8) Scum Pumps
(a) Number - Four
(b) Type
Vertical, extended, open-shaft, dry pit, non-
clog, constant speed.
(c) Capacities
Pump Nos. 1 and 2 - 100 GPD @ 61.6' TDH
Pump Nos. 3 and 4-90 GPM @ 84' TDH
(9) Tertiary Sludge Pumps
(a) Number - Two
(b) Type
Horizontal ball-bearing, non-clog, variable
speed.
(c) Capacity, Each - 600 to 1,200 GPM @ 69.5' TDH
P. Chemical Feed Equipment - Primary
(1) Number of Units - One
(2) Type - Dry
176
-------
(3) Feed Rate - 350 Lb/Hour
(4) Dosage Rate of Lime - 200 mg/1
Q. Chemical Feed Equipment - Tertiary
(1) Number of Units - One
(2) Type - Dry
(3) Feed Rate - 350 Lb/Day
(4) Dosage Rate of Alum - 40 mg/1
R. Surge Storage Tank Capacity Determination
Daily Raw Sewage Flow: 3.60 MGD Ave. 24 Hr. Flow
0.73 MGD Infiltration
4.32 MGD Total Raw Sewage
18,000 GPH
3,000 GPM
1% Daily Flow: 43,200 Gallons
Daily Filter Flow: 2,500 GPM Ave. 24 Hr. Flow
1,250 GPM Recirculation Flow
3,750 GPM Total Flow
225,000 GPM
5.40 MGD
Filter Capacity:
28.0' long x 10.0' = 280 SF x 5 GPM/SF =
1,400 GPM Filter Rate Per Filter
3 Filters x 1,400 GPM = 4,200 GPM Rate = 252,000 GPH
6.05 MGD
Backwash Rate:
15 GPM/SF Filter x 280 SF = 4,200 GPM
177
-------
Backwash Time:
8 Minutes x 4,200 GPM = 33,600 Gallons
Backwash Volume Only: = 33,600 Gallons
Surface Wash Rate:
0.71 GPM/SF Filter x 280 SF = 200 GPM
Surface Wash Time:
4 Minutes x 200 GPM = 800 Gallons
Surface Wash Volume Only: = 800 Gallons
Backwash Volume: 33,600 Gallons
Surface Wash Volume: 800 Gallons
Total Backwash per Filter 34,400 Gallons
Filter Plant Flow: 252,000 GPM*
Filter Plant Flow During Backwash 240,800 GPM**
* 3 Filters Operating - Full Capacity
** 2 Filters on Plus 1 On For 52 Minutes
178
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DETERMINATION OF SURGE STORAGE REQUIRED
Time
6- 7 A.M.
7- 8
8- 9
9-10
10-11
11-12 Noon
12- 1 P.M.
1- 2
2- 3
3- 4
4- 5
5- 6
6- 7
7- 8
8- 9
9-10
10-11
11-12 Midnight
12- 1 A.M.
1- 2
2- 3
3- 4
4- 5
5- 6
Per Cent
Flow
Factor
3.0
3.0
4.0
4.5
6.5
6.5
6.5
6.5
4.5
4.5
4.5
4.5
5.0
5.0
5.0
5.5
5.0
5.0
1.5
1.5
1.5
1.5
2.5
2.5
Raw
Sewage
Gallons
129,
129,
172,
194,
280,
280,
280,
280,
194,
194,
194,
194,
216,
216,
216,
237,
216,
216,
64,
64,
64,
64,
108,
108,
600
600
800
400
800
800
800
800
400
400
400
000
000
000
000
600
000
000
800
800
800
800
000
000
B/W Return
Gallons
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
+ 34
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
,400
-
Total
Flow
Gallons
164
129
207
194
315
280
315
280
228
194
228
194
250
216
250
237
250
216
99
64
99
64
142
108
,000
,600
,200
,400
,200
,800
,200
,800
,800
,400
,800
,400
,400
,000
,400
,600
,400
,000
,200
,800
,200
,800
,400
,000
Filter
Capacity
Gallons
240,000**
252,000*
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
240,800
252,000
Accumulation
Surge
Storage
Gallons
- 76,800
- 122,400
- 33,600
- 57,600
+ 74,400
+ 28,800
+ 74,400
+ 28,800
- 12,000
- 57,600
- 12,000
- 57,600
+ 9,600
- 36,000
+ 9,600
- 14,400
+ 9,600
- 36,000
- 141,600
- 187,200
- 141,600
- 187,200
- 98,400
- 144,000
Total
Build-Up
Surge
Storage
Gallons
74
103
177
206
194
136
124
67
76
40
50
35
45
9
0
0
0
0
,400
,200
,600
,400***
,400
,800
,800
,200
,800
,800
,400
,000
,600
,600
0
0
0
0
0
0
* 3 Filters Operating - Full Capacity
** 2 Filters on Plus 1 on For 52 Minutes
*** Surge Storage Required
-------
APPENDIX B
METHOD FOR TOTAL PHOSPHORUS ANALYSIS
Phosphorus, Total and Total Soluable
The sanitary significance of the various phosphorus compounds has
been discussed in Section III. Since the permit for the Hatfield plant
specifies an effluent phosphorus limit, the sewage must be analyzed
routinely for phosphorus content.
The procedure which follows is for nitric acid-sulfuric acid sam-
ple digestion, followed by the stannous chloride method of phosphorus
determination. This method is suitable for work on domestic wastewater.
Alternate procedures can be found in "Standard Methods" and "FWPCA
Methods".
1. Scope and Application
1.1 The following procudure can be utilized to determine the total
phosphorus and total filterable (soluble) phosphorus content
in domestic wastes, industrial wastes and natural waters.
1.2 The procedure can be used to measure phosphorus in the range
of 0.01 to 6 mg P/l. An extraction procedure is used to de-
termine low range phosphorus concentrations. For values above
6 mg P/l, the vanadomolybdic acid method, found in "Standard
Methods" must be used.
2. Summary of Method
2.1 Poly and organic forms of phosphorus are converted to ortho-
phosphate by digesting the sample with nitric and sulfuric
180
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acids. The orthophosphate then reacts with ammonium molyb-
date under acid conditions to form a complex compound known
as ammonium phosphomolybdate.
o
P04~J + 12(NH4)2 Mo04 + 24H+ } (NH4)3P04 • 12Mo03 + 21 NH4+ + 12H20
Stannous chloride is then added as a reducing agent. It
reacts with the ammonium phosphomolybdate to form a blue
colored compound known as molybdenum blue. The formula for
molybedenum blue is not known. The blue color resulting
from this reaction is proportional to the amount of ammonium
phosphomolybdate present. The stannous chloride does not
react with any excess ammonium molybdate.
The intensity of the blue color is measured using a
spectrophotometer. Phosphorus concentration can then be de-
termined from this data.
3. Sampling and Preservation
3.1 If the sample cannot be analyzed immediately, the portion
intended for the total soluable phosphorus determination should
be filtered before being stored. The samples should not be
stored in plastic bottles because there is the possibility
that phosphorus compounds can be adsorbed onto the walls of
the plastic containers.
4. Interferences
4.1 Gross positive errors can come from using glassware cleaned
with phosphate detergents.
181
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5. Apparatus
5.1 Hot plate
5.2 Spectrophotometer with curvettes
If the analyst is not familiar with the limitations and idio-
syncrasies of his spectrophotometer, he should refer to pages
9 - 12 of "Standard Methods" and to the manufacturers instruct-
tions.
5.3 Acid - cleaned glassware
All glassware should be cleaned with hot dilute HC1 and rinsed
several times with distilled water. The glassware should be
reserved solely for phosphorus determinations and after each
use, it should be washed and filled with distilled water until
needed. If this procedure is used, the acid treatment is
only required occasionally. Phosphate detergents should never
be used on glassware used for phosphorus determination.
Preliminary Measures:
A. Filtration
a.l Separation of filterable (soluble) phosphorus from non-
filterable (particulate) phosphorus is made using a .45
membrane filter. This procedure is purely an analytical
technique which is convenient and easily reproduceable.
It is not a true separation of soluble and suspended
phosphorus compounds.
a.2 The filters must be washed before use because they can
182
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contain significant amounts of phosphorus. They can
be washed by either soaking filters (50 per 20 ml water)
in distilled water for 24 hours or soaking filters (50
per 20 ml water) in distilled water for one (1) hour,
changing water and soaking filters an additional three
(3) hours.
Preparation of Calibration Chart
b.l Reagents
Stock Solution
Dissolve 0.4393 g of pre-dried KH^PO^ in distilled water
and dilute to 1 liter 1 ml = 0.1 mg P.
Standard Solution A
Dilute 100 ml of stock solution to 1 liter. 1 ml = 0.01
mg P.
Standard Solution B
Dilute 100 ml of Standard Solution A to 1 liter 1 ml =
0.001 mg P.
b.2 Prepare a series of standards by diluting suitable volumes
of Standard Solution A and B to 100 ml with distilled water.
The following dilutions are suggested.
ml of S. Sol B Cone, mg P/l
0.0 0.00
2.0 0.02
5.0 0.05
10.0 0.10
183
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ml of S. Sol A Cone, mg P/l
2.0 0.20
5.0 0.50
8.0 0.80
10.0 1-00
20.0 2.00
30.0 3.00
Carry the standard solutions through the digestion and
the stannous chloride stages.
Allow color to develope over 10 minutes but less than
12 minutes, then measure the color photometrically at
690 mu. Plot a calibration curve on rectangular graph
paper. The calibration curve may deviate from a straight
line at the upper range.
C. Digestion
c.l The analyst will have to have a rough idea of the
amount of phosphorus to expect at the various sampling
locations in order to be able to select an appropriate
sample size. If 100 ml of sample will contain more
than 0.2 mg of phosphorus, an aliquot will have to be
used. The following table can be used to determine
sample size.
Sample Size Phosphorus Concentration
100 ml 2 mg/1 P or less
50 ml 4 mg/1 P
184
-------
Sample Size Phosphorus Concentration
25 ml 8 mg/1 P
10 ml 20 mg/1 P
5 ml 40 mg/1 P
2.5 ml 80 mg/1 P
c.2 Procedure
An appropriately sized sample, 1 ml conc.I^SO^ and 5 ml
concentrated HNO-j are added to a flask.
Digest the sample to a volume of 1 ml, then continue
digesting until the solution becomes colorless.
Cool and add approximately 20 ml distilled water, 1
drop phenolphthalein indicator and as much IN NaOH as
necessary to produce a faint pink color. Transfer
the solution to a 100 ml volumetric flask, filtering
with washed filters if the sample contains particulate
matter, If the sample had to be filtered, wash the
filter with distilled water and add these washings to
the volumetric flask. Adjust the sample volume to 100
ml and proceed with the colorimetric determination.
Phosphorus Determination
6. Reagents
6.1 Phenolphthalein Indicator Solution
6.2 Strong Acid Solution
Slowly add 300 ml concentrated HSO^ to 600 ml distilled water.
185
-------
Cool and add 4 ml concentrated HNOo and dilute to 1 liter.
6.3 Ammonium Molybdate Reagent I
Dissolve 25 g (NH^),Mo024 • 4 H20 in 175 ml distilled water.
cautiously add 280 ml concentrated H2SO^ to 400 ml distilled
water. Cool, add the molybdate solution and dilute to 1 liter.
6.4 Stannous Chloride Reagent I
Dissolve 2.5 of SnCl2 • 2 H20 in 100 ml glycerol. Heat in
a water bath and stir until all the crystals are dissolved.
This reagent is realitively stable. If any turbidity developes
when the reagent is added to the sample, the quality of the
stannous chloride is questionable.
7. Procedure
7.1 If the sample is pink from the phenophthalein addition in
the digestion stage, add strong acid solution dropwise until
the sample turns colorless.
7.2 Add 4 ml molydbate reagent I and 0.5 ml stannous chloride
reagent I and mix well. Color development is dependant on
the temperature of the solution, therefore all samples,
reagents, and standards should be within 2° C. of each
other and be between 20° C. and 30° C.
7.3 After 10 minutes, but before 12 minutes, measure the color
using a spectrophotometer set at 690 mu. Use calibration
chart to determine phosphorus determination by direct readout
from absorbance data. Use a distilled water blank and run
186
-------
at least one standard to check the calibration curve. A
blank on the reagents should also be run.
8. Extraction
At phosphorus concentrations below 0.1 mg P/l an extraction pro-
cedure can be used for increased sensitivity and more accurate
results. This procedure can be found in "Standard Methods."
The following table of conversion factors can be used to compare the
various forms of phosphorus.
To Convert X to P To Convert P to X
Multiply by: X Multiply by:
1.000 P 1.00
.451 P205 3.29
.327 P04 3.06
.316 H3P04 3-16
.256 A1P04 3.90
.200 Ca3 (P04)2 5.00
.181 Ca5OH (P04)3 5.51
187
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APPENDIX C
INDUSTRIAL SURCHARGE PROGRAM
The Hatfield Authority has instituted a
program whereby industry must pay a
"fair share" for any extra operating costs
imposed upon the facility above environ-
mental waste. A portion of the permit
application has been included herein.
188
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HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
APPLICATION FOR INITIAL INDUSTRIAL WASTE DISCHARGE PERMIT
I/WE, the undersigned, hereby make application to the Hatfield Township
Municipal Authority for an initial permit to discharge industrial waste
to the Hatfield Township sewerage system, in accordance with section 7,
Ordinance No. 114, of the Township of Hatfield, Montgomery County, Penn-
sylvania.
I/WE understand that the Authority has imposed regulations and require-
ments for the discharge of industrial waste to the Hatfield Township
sewerage system, as permitted under said Section 7, Ordinance 114, and
that the following general regulations and requirements apply:
A. All industrial waste flows shall be metered by a separate
sewage meter,- which meter shall be satisfactory to the Autho-
rity, and shall provide for a separate remote recording de-
vice at an accessible location which shall have a totalizer,
and a 30-day recording chart.
B. The meter described in A. above shall be installed and fully
operable within 90-days after receipt of the Initial Industrial
Waste Discharge Permit. All costs incident to the furnishing,
installation, initial calibration, and maintenance on a contin-
uing basis of said meter is and shall be my/our responsibility,
and the I/we will provide to the Authority or its designated
representative within 15-days of receipt of the Initial Indus-
trial Waste Discharge Permit full details on the proposed meter
installation, and that such installation will commence only
upon the written authorization of the Authority, which shall
not be more than 10-days after receipt by the Authority of the
details of the proposed meter installation.
C. The meter installation shall be such that samples of the in-
dustrial waste flow shall be readily obtainable at the meter
location, &nd I/we understand that the Authority will collect
samples three times yearly for the analysis of the waste flow,
one of which shall be analyzed by an independent certified
laboratory, and two of which will be analyzed at the Hatfield
Township Advanced Waste Treatment Facility laboratory. I/we
further understand and agree that a charge for these industrial
waste flow sample analyzation will be $ , and that a
check for $ is attached to this application.
D. I/we understand that the Authority may at any time request that
the meter be calibrated, and that the cost of such calibration
189
-------
shall be mine/ours if the meter is found to be out of calibra-
tion, or shall be the Authority's if the meter is found to be
correct .
E. The charge for metered industrial waste flow shall be at a single
rate per 1000 gallons, regardless of volume, which rate is cur-
rently $ _ per 1000 gallons.
F. There shall be a surcharge for industrial waste flow which shall
be computed as follows:
F = 1 + R (S + B + P + N + A) + C
Where F = Facter to multiply the basic metered industrial pro-
cess charge for a surcharge for strengths in excess of
normal domestic sewage strengths.
R = 0.5 = Ratio of the estimated cost of treatment for
quality, and the total sewerage cost.
S = Strength factor for total suspended solids computed at
e _ n An -Sl ~ 20° mg/1 ^
S ~ °-4° ( 200 mg/1 )
Where S^ is the industrial total suspended solids in
mg/1.
B =
= Strength factor for BOD^ computed at
B = 0.30 (Bl ~ 20°
200 mg/1
Where B^ is the industrial BOD^ in mg/1 .
P = Strength factor for Phosphorus, computed at
P = 0.15 fpl ~ 8 mg/1)
8 mg/1
Where Pj is the industrial P in mg/1 .
N - Strength factor for Nitrogen, computed at
N = o.lO (Nl ~ 25 mg/1)
25 mg/1 !
Where N-^ is the sum of the industrial NH3, NO3 and
NO 2 in mg/1 .
190
-------
A = Strength factor for Acid/Alkali, computed at
A = 0.02 (7.0 - Ajj when A2 •<. 7.0
A = 0.02 (A1 - 7.0) when A >>7.0
Where A^ is the industrial pH.
C = Strength factor for Chlorine Demand, computed at
C = 0.03 x 8.33 Pc (CD - 5 mg/1)
Where PC = Cost of Chlorine per Pound
CD = Industrial Chlorine Demand in mg/1.
G. I/we understand the because the Hatfield Township Advanced
Waste Treatment Facility will not realize any benefit if my/
our industrial process flow has any strength factor with a
negative value, that any such negative strength factor value
shall be considered as being zero.
H. The term of the Initial Industrial Waste Discharge Permit is
one (1) year from the date of issue.
I. An application for a Renewed Industrial Waste Discharge Per-
mit shall be filed thirty (30) days prior to the expiration
date of the Initial Industrial Waste Discharge Permit.
J. I/we understand that the Initial Industrial Waste Discharge
Permit will contain Special Conditions for the discharge of
my/our industrial waste.
K. I/we understand that items prohibited from discharge to the
sewage collection system as defined in Section 6 of Ordinance
114f and the limitations of items a. through n. of Section 7
of Ordinance 114 of the Township of Hatfield will be strictly
enforced.
L. I/we understand the should I/we be in violation of the pro-
hibitions of Section 6 of Ordinance 114, the limitations of
Section 7 of Ordinance 114, or limitations imposed under Spec-
ial Conditions as indicated in K. above, my/our Initial Indus-
trial Waste Discharge Permit will be revoked and I/we must
cease discharge to the Hatfield Township Sewage Collection
System, and that I/we will be responsible for all costs in-
curred by the Hatfield Township Municipal Authority for damage
or repair to the Sewage Collection System and the Advanced
Waste Treatment Facilityf and for all costs incurred to re-
191
-------
establish the correct operating conditions at the Advanced
Waste Treatment Facility, by virtue of my/our failure to
conform to the limitations and prohibitions.
M. I/we understand that if my/our waste flow consists only of
sanitary sewage flows, and that I/we have no industrial pro-
cess flow, items A. through G., and item J. above shall not
apply, and that my/our sewage rate shall be established in
accordance with Section 3, Ordinance 114 of the Township of
Hatfield.
I/WE hereby declare that the following information furnished is true
and accurate:
1. Number of permanent employees_
2. Number of permanent employees working full-time on premises
3. Average number of hours per day spend on premises by employees
not working full-time on premises .
4. Do you provide showers for your employees? .
5. Indicate length of operating day .
How many days per week? .
How many shifts per week?
Number of employees per shift_
6. Do you meter your water consumption?
If so, attach water consumption data for preceeding 4 quarters.
If not, estimate water consumption, and industrial waste flow
7. Describe your operation and the nature of your industrial pro-
cess waste:
192
-------
8. Attach an analysis of your waste from an independent certified
laboratory indicating Total Suspended Solids, BOD5, Phosphorus
as P, Ammonia Nitrogen, Nitrate Nitrogen, Nitrite Nitrogen, pH,
and Chlorine Demand. Include also any items which may, by vir-
tue of your process conceivably have an effect upon the opera-
tion of the Advanced Waste Treatment Facility, such as, color,
heavy metals, oil, grease, and toxic materials.
9. Refer to paragraphs a. through n. Section 7, Ordinance 114 at-
tached. Indicate if your waste is within the limits prescribed.
If not, indicate variances from conditions set forth in Ordinance
114.
10. Remarks:
DATE:
(Name of Sole Proprietorship/Partnership
/Corporation)
BY:
(Signature)
(Title)
(Address of Organization)
Submit Application with supporting data in duplicate to:
Director of Operations
Hatfield Township Municipal Authority
Advance Lane, Colmar, Pennsylvania 18915
193
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APPENDIX D
ANALYTICAL DATA
The following pages summarize analytical data for the period April 1973-
March 1974.
1. The location of each sample point is as follows:
Raw - Sample is taken from wet well of Pump Station #1 and Wet
Well of Pump Station No. 2. Combined raw is mixed sample based
upon flows from Montgomeryville and Hatfield.
Surge - Effluent sample is taken just prior to flash mixer.
Primary - Sample is taken from overflow trough of Clariflocculator.
Secondary - Sample from overflow trough.
Tertiary - Sample is obtained from effluent chamber of tertiary
tube clarifiers.
Filter - Sample point is on filtered water effluent line.
Final - Samples are taken after chlorination, just prior to discharge
to stream.
Upstream - Grab Samples are taken at least 100 feet upstream of plant
outfall on West Branch of the Neshaminy Creek.
Downstream - Grab samples are taken approximately 150 feet downstream
of plant outfall along the Neshaminy Creek.
2. All values are reported as average values for the test period, except
pH values, which are median values.
3. A testing schedule for laboratory sampling is contained in Table D-l.
4. Data for the period April 1974 through December 1974 is included,
although it is beyond, and not a part of, the test period.
5. With respect particularly to upstream and downstream COD, at many
times of the year, the only flow upstream is the effluent from the
Lansdale Sewage Treatment Plant, which operates as a secondary treat-
ment plant sometimes, but mostly as a primary treatment plant. There-
fore, although the values appear rather varied, they were reported as
entered.
194
-------
TABLE D-l. GRANT PERIOD LABORATORY TESTING SCHEDULE
COD
MWF
MWF
MWF
MWF
MWF
MWF
MWF MWF
MWF
MWF
P-Total
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
MWF
MWF
P-Ortho
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
M-F
MWF
MWF
P-Total
Soluble
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
P-Soluble
Ortho
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
T-R
NH3-N
M-F
M-F
M-F
M-F
TKN
M-F
M-F
M-F
M-F
N02-N
M-F
M-F
M-F
M-F
NOs-
M-F
M-F
M-F
M-F
T.S.S.
M-F
M-F
M-F M-F
M-F
M-F iM-F ] M-F
M-F
M-F
M-F
M-F
T.S.
R
R
V.S.S.
M-F
M-F
M-F
M-F
M-F
M-F M-F
M-F
M-F
M-F
M-F
M-F
V.S.
R
Fecal
Col iform
M = Monday, T = Tuesday, W =« Wednesday, R = Thursday, F = Friday
-------
APRIL 1973 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
195.
76.
36.
48.
0.
0.
84.
6.
5.
3.
85.
71
379.
35.
99.
Surge
0
8
2
2
06
08
4
9
1
24
0
0
9
6
574.
115.
68.
11.
0.
0.
79.
7.
9.
4.
1447.
65.
805.
29
_
4
7
1
5
18
24
6
5
0
57
0
5
0
Prim.
316.2
74.5
40.0
48.4
0.14
0.02
88.4
8.7
3.7
1.6
112.0
56.8
490.0
15.7
_
Sec.
175.7
34.6
-
24.4
0.11
0.06
-
8.7
2.4
1.81
101.0
54.8
465.0
24.7
_
Tert.
_
14.9
-
33.1
0.06
0.09
-
7.8
1.2
1.1
16.0
-
363.0
17.4
_
Filt.
67.8
7.7
-
-
0.08
0.18
-
7.9
1.2
0.4
5.0
64.5
430.0
13.7
_
Final Upstream
78.
2.
27.
52.
0.
0.
79.
7.
0.
0.
7.
62.
535.
16.
115.
3 29.3
9 3.9
2
6
05 0.13
06 0.38
8
9 7.1
7 1.6
3 1.60
0 13.0
2 41.4
0
5
0
Downstream
10.2
4.0
-
-
0.10
0.26
-
7.5
1.5
1.1
19.0
39.0
-
-
_
*Median Value
-------
MAY 1973 DATA
May 1 - May 14, 1973
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
252.9
93.1
7.*2
37.8
0.9
0.2
45.0
7.1
6.5
6.0
89.1
43.0
583.5
32.0
122.3
Surge
558.5
139.6
10.8
47.8
0.21
0.12
58.6
7.8
22.3
9.0
653.7
60.0
1071.5
27.2
181.4
Prim.
178.9
60.7
6.4
59.9
0.31
0.16
66.3
8.8
2.3
1.9
46.7
36.4
611.5
14.2
172.8
Sec.
13.8
19.4
-
-
1.74
0.28
-
7.7
2.2
1.8
18.3
46.9
628.0
14.3
134.6
Tert.
72.8
5.2
-
-
1.20
0.19
-
7.6
0.6
0.3
5.0
50.0
607.5
11.3
117.0
Filt.
59.9
6.1
-
-
1.28
0.26
-
7.2
0.4
0.3
6.5
25.0
590.5
11.2
110.0
Final
51.7
1.3
7.2
97.4
0.8
0.3
-
7.0
0.7
0.3
52.1
68.0
609.0
13.0
103.9
Upstream Downstream
-
4.6
-
-
0.23
0.69
-
7.0
2.0
1.1
33.3
57.7
-
-
63.4
-
1.7
-
-
1.05
0.34
-
7.2
1.1
0.3
54.3
61.5
-
-
95.4
^Median Value
-------
00
MAY 1973 DATA
May 15 - May 30, 1973
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
346.4
109.3
4.2
34.0
0.09
0.15
38.2
7.0
9.9
8.7
123.8
48.9
501.5
21.6
_
Surge
600.5
124.0
8.5
59.4
0.14
0.04
67.9
7.8
34.4
10.9
6336.3
48.2
2061.5
19.7
_
Prim.
149.98
60.3
4.2
72.2
1.0
0.3
76.4
8.8
3.9
2.6
110.8
51.3
594.0
37.5
—
Sec.
89.9
27.3
8.5
67.9
2.5
0.5
76.4
7.7
3.7
2.5
32.1
42.4
568.5
17.8
—
Tert.
-
10.5
-
-
2.5
1.5
-
7.6
0.8
0.5
7.2
54.9
552.0
22.5
-
Flit.
51.5
14.8
-
-
4.1
1.0
-
7.1
0.6
0.6
6.6
90.0
562.5
8.6
-
Final
29.5
4.9
12.7
29.7
3.5
0.2
42.4
6.9
0.8
0.5
13.3
76.1
515.0
10.5
-
Upstream Downstream
-
4.5
-
-
0.3
0.8
-
7.0
3.2
1.1
25.8
71.2
-
-
-
-
4.7
-
-
1.4
0.4
-
7.1
2.3
0.3
12.0
60.0
-
-
-
*Median Value
-------
JUNE 1973 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
336.
104.
2.
38.
0.
0.
41.
7.
8.
5.
116.
83.
695.
37.
157.
1
7
8
5
5
2
3
4
1
9
0
7
0
3
8
Surge
-
146.2
-
-
0.8
0.1
-
7.8
21.5
28.0
-
35.9
-
35.3
466.9
Prime.
781.8
124.9
-
-
1.9
0.4
-
8.5
3.9
5.9
-
48.4
1019.0
38.8
253.5
Sec.
269.9
25.0
-
-
2.2
1.4
-
7.6
4.9
2.5
118.0
52.1
840.0
30.2
161.9
Tert.
244.8
9.2
-
-
2.0
1.4
-
7.5
1.1
0.5
18.6
58.3
673.0
26.7
120.8
Filt.
289.2
9.1
-
-
2.4
1.7
-
7.0
0.6
0.5
9.4
82.0
699.0
27.9
113.9
Final
223.4
4.3
1.4
18.1
2.4
1.5
19.5
7.1
0.5
0.4
11.7
74.0
715.0
28.0
124.0
Upstream Downstream
270.7
5.4
-
-
0.3
0.4
-
-
3.4
1.3
31.0
58.9
352.0
26.4
69.2
494.
5.
-
-
1.
0.
-
-
3.
1.
34.
65.
518.
24.
83.
5
6
2
5
7
6
5
5
0
2
4
*Median Value
-------
JULY 1973 DATA
Parameter
COD
BOD 5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
601.2
111.0
10.3
60.7
0.1
0.7
71.0
7.1
7.9
6.4
232.0
87.1
1252.0
43.3
_
Surge
445.4
124.8
-
-
0.2
0.2
-
6.7
21.5
26.6
1058.0
49.7
-
35.9
_
Prim.
220.7
66.0
-
-
0.2
0.1
-
8.1
3.1
2.2
105.4
69.2
810.0
27.0
_
Sec.
264.1
8.5
-
-
1.9
1.8
-
6.9
3.2
1.9
77.0
64.7
835.0
24.5
_
Tert.
234.1
2.3
-
-
2.5
0.9
-
6.1
0.3
0.0
17.5
59.5
775.0
26.5
_
Flit.
_
10.9
-
-
2.1
1.1
-
6.1
1.2
0.0
12.3
71.9
789.0
21.2
15.9
Final
280.7
6.5
1.6
30.7
1.9
0.9
32.3
5.9
0.6
0.0
13.9
57.4
850.0
23.5
130.0
Upstream
-
11
-
-
1
0
-
-
3
2
35
36
514
27
_
.0
.1
.2
.5
.2
.5
.7
.0
.5
Downstream
-
9.
-
-
1.
0.
-
-
2.
2.
35.
55.
600.
23.
_
5
2
3
0
2
8
4
0
5
*Median Value
-------
AUGUST 1973 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
720
65
3
-
0
0
11
7
6
6
116
82
938
38
240
.8
.0
..5
.09
.0
.2
.7
.1
.0
.8
.4
.0
.8
.6
Surge
444.6
78.4
-
-
0.09
0.0
-
7.6
19.6
9.1
688.2
48.8
2866.0
40.4
221.5
Prim.
441.7
59.3
-
28.7
0.15
0.0
-
8.3
2.1
2.1
68.5
77.1
2494.0
15.0
253.5
Sec.
226.4
8.5
-
24.7
0.90
0.7
-
8.1
1.7
0.8
32.9
66.1
495.0
40.5
122.1
Tert.
434.5
2.3
-
-
0.77
0.5
-
7.2
0.3
0.1
9.9
69.9
960.0
32.7
130.3
Filt.
374.0
2.4
-
-
0.64
0.8
-
7.1
0.4
0.3
8.1
54.0
880.0
35.9
97.3
Final
338.8
2.6
2.1
0.5
0.50
1.0
2.4
6.8
0.2
0.5
8.1
61.5
806.0
36.2
101.7
Upstream
336.
3.
-
-
0.
0.
-
-
2.
2.
13.
-
534.
-
167.
5
4
43
2
2
4
8
0
4
Downstream
309.8
2.6
-
-
0.60
0.3
-
-
1.6
1.6
10.0
-
679.0
-
121.1
^Median Value
-------
SEPTEMBER 1973 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
324.0
94.6
-
-
0.1
0.3
-
8.1
12.9
6.0
372.5
82.2
542.5
17.8
196.4
Surge
368.8
120.9
-
0.47
0.0
1.0
-
8.0
21.8
9.1
1579.3
65.8
953.5
26.3
154.5
Prim.
276.1
66.1
-
0.31
0.3
0.6
-
8.4
5.0
2.1
-
70.9
804.5
14.0
136.0
Sec.
222.7
14.1
-
-
0.1
0.7
-
8.1
6.2
0.9
204.5
79.3
841.0
18.6
101.9
Tert.
232.6
17.0
-
-
1.4
0.7
-
7.2
0.5
2.4
-
62.8
825.0
35.9
121.2
Filt.
198.7
9.7
-
0.23
1.3
1.1
-
7.4
2.9
0.9
12.8
66.2
744.0
11.7
84.2
Final
197.8
5.8
-
-
1.3
0.6
-
6.7
-
-
4.7
78.4
856.0
11.7
132.6
Upstream
179
13
-
-
0
0
-
-
5
2
4
62
930
65
112
.7
.6
.3
.3
.3
.4
.1
.5
.0
.4
.9
Downstream
160.
10.
-
-
4.
0.
-
-
3.
1.
2.
57.
854.
11.
134.
1
4
9
3
6
6
7
4
0
2
2
*Median Value
-------
OCTOBER 1973 DATA
Parameter
COD
BOD 5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
407.
51.
-
50.
0.
0.
-
8.
6.
5.
246.
67.
1139.
16.
166.
8
3
7
2
2
1
9
3
3
4
0
6
8
Surge
299.4
54.6
-
47.0
0.1
0.2
-
8.3
8.0
5.8
671.0
61.6
1490.0
21.7
195.3
Prim.
187.8
43.0
-
33.8
0.5
0.6
-
9.3
4.8
3.2
93.2
61.5
918.0
19.0
214.0
Sec.
137.6
11.2
-
14.1
0.4
1.7
-
7.9
1.7
0.6
50.5
55.5
860.0
39.4
192.3
Tert.
310.3
5.2
-
4.4
0.6
1.2
-
7.1
0.9
0.3
12.2
39.2
973.0
27.9
165.0
Filt.
118.4
4.3
-
4.4
0.3
1.3
-
7.3
0.8
0.9
10.0
53.3
958.0
22.0
160.5
Final
109.6
2.0
-
5.6
0.3
1.2
-
7.1
0.2
0.3
16.4
43.5
891.0
22.0
205.3
Upstream Downstream
138.7
6.0
-
5.6
1.1
1.1
-
-
4.7
1.8
15.2
54.9
319.0
20.7
165.6
96
3
-
5
1
1
-
-
4
4
19
61
550
13
136
.9
.3
.4
.2
.2
.6
.4
.2
.8
.0
.5
.3
^Median Value
-------
NOVEMBER 1973 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
M TKN
o
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
223.
72.
-
54.
0.
3.
8.
3.
3.
342.
54.
1630.
48.
162.
8
2
9
08
0
4
9
24
0
5
0
0
8
Surge
297.8
72.2
-
-
0.07
3.0
8.7
4.11
3.20
685.1
56.9
1344.0
36.0
241.7
Prim.
219.0
52.5
-
35.6
0.10
1.08
9.3
3.9
2.0
50.7
41.3
712.0
17.0
172.6
Sec.
160.5
7.7
-
17.1
0.11
23.2
9.1
0.8
0.68
49.9
63.8
931.0
22.0
111.9
Tert.
195.6
5.5
-
6.2
0.09
24.3
7.2
0.4
0.40
12.9
48.3
847.0
14.0
119.8
Filt.
116.6
4.0
-
5.0
0.09
19.9
7.6
0.4
0.38
7.0
49.1
809.0
24.0
152.8
Final
97.6
3.1
-
4.0
0.05
12.8
7.3
0.3
0.32
4.9
46.6
800.0
24.0
181.9
Upstream
138
7
-
4
0
29
7
1
0
12
47
652
15
167
.4
.3
.8
.13
.4
.8
.0
.77
.2
.8
.0
.0
.0
Downstream
132.0
5.0
-
5.1
0.12
31.5
7.9
0.8
0.70
12.5
40.5
654.0
35.0
142.8
*Median Value
-------
DECEMBER 1973 DATA
t-o
O
Ln
Parameter
COD
BOD 5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
256.7
109.0
15.0
*
31.0
0.6
46.0
8.0
7.2
7.5
269.0
64.0
1392.0
17.0
193.8
Surge
395.
134.
_
60.
0.
-
7.
7.
7.
1409.
64.
5493.
46.
238.
4
0
0
9
9
0
1
0
0
0
0
8
Prim.
241.1
118.0
13.0
31.0
0.1
44.0
8.4
2.9
3.4
156.0
59.0
1283.0
31.0
146.6
Sec.
140.0
92.0
_
30.0
0.6
-
8.3
1.1
1.3
25.0
71.0
841.0
13.0
115.9
Tert.
173.
22.
_
5.
0.
-
7.
0.
0.
15.
61.
894.
12.
97.
1
0
8
0
3
3
1
0
0
0
0
5
Filt.
183.0
19.0
_
5.7
0.1
-
7.5
0.2
0.1
50.0
55.0
866.0
12.0
151.3
Final
143.0
16.0
0.7
1.7
0.1
2.4
7.7
0.1
0.1
11.0
55.0
735.0
12.0
132.1
Upstream Downs
178.
15.
_
—
0.
-
-
1.
2.
14.
41.
513.
12.
120.
4
0
0
9
3
0
0
0
0
9
198.1
21.0
__
-
0.0
-
-
1.8
2.2
61.0
44.0
671.0
10.0
104.4
*Median Value
-------
JANUARY 1974 DATA
o
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
IS
TVS7,
Alk.
Raw Surge Prim. Sec.
_ _ _ _
81.1 64.6 59.6 51.4
_ _ _ _
44.1 -
_ _
0.05
_ _ _
7.4 7.4 8.3 7.4
2.9 4.5 2.8 3.4
2.3 - - -
58.6 149.0 56.3 60.2
76.1 69.7 68,9 58.7
_ _ _
- - - -
_ _
Tert. Filt. Final Upstream
_
24.1 9.9 3.0 5.8
- - - -
- 1.2 -
_
- - - -
- - - -
7.2 7.3 7.1 7.5
0.6 - 0.5 0.7
0.01
24.7 5.0 8.4 9.9
63.3 52.0 68.1 77.6
- - - -
- - - -
_
Downstream
-
5.3
-
-
-
-
-
7.4
0.8
-
14.1
62.8
-
-
_
*Median Value
-------
r-o
a
FEBRUARY 1974 DATA
Parameter Raw Surge Prim. Sec. Tert. Filt. Final
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
99.7
82.0
-
8.
4.
0.
235.
70.
676.
28.
-
1
2
47
2
1
2
2
112.
-
8.
6.
2.
1791.
54.
2931.
87.
-
6
4
1
20
0
6
0
7
100.5
-
9.1
2.6
1.40
-
63.1
-
59.6
_
25.4
-
7.9
1.5
0.45
96.9
64.0
857.3
21.2
_
17.4
-
7.7
0.8
0.35
23.3
49.9
795.3
11.7
_
13.1
7.6
-
7.7
0.7
0.25
7.2
63.4
739.0
11.5
_
3.
10.
-
7
0
0
11
54
-
11
— ^~
8 9.7
1
-
.7 8.2
.7 0.5
.13 0.35
.1 22.9
.9 50.6
—
.0
8.2
_
8.1
0.7
0.25
19.3
40.9
_
_
^Median Value
-------
MARCH 1974 DATA
Parameter
COD
BOD 5
Org-N
NH3-N
N02-N
N03-N
o TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
*Median Value
Raw
432.0
73.7
-
89.3
0.06
0.01
121.3
8.0
8.6
4.2
215.3
73.2
632.9
24.2
_
Surge
408.
90.
-
-
0.
0.
-
8.
8.
4.
263.
64.
1255.
39.
_
0
4
06
01
2
5
7
8
2
0
0
Prim.
441.6
61.4
-
65.2
0.07
0.02
94.0
9.3
6.5
4.3
175.6
63.7
684.1
21.6
340.0
Sec.
327.4
14.2
25.2
66.1
0.02
0.01
91.3
8.1
2.3
1.9
46.9
66.5
565.9
23.1
100.0
Tert.
239.1
10.2
-
-
0.06
0.04
-
7.8
1.1
0.8
17.6
57.4
660.1
21.7
_
Filt.
345.6
8.1
-
-
0.06
0.04
-
7.6
1.1
0.9
7.4
61.7
602.1
18.3
_
Final
181.3
5.1
40.7
12.7
0.10
0.02
14.6
7.5
0.7
0.7
7.0
50.3
702.7
15.0
180.0
Upstream
374.
10.
-
-
0.
0.
-
7.
1.
1.
101.
48.
-
-
_
4
9
07
05
7
3
4
9
6
Downstream
345.
6.
-
-
0.
0.
-
7.
1.
1.
12.
55.
-
-
_
6
5
07
05
7
6
6
6
4
-------
APRIL 1974 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
*Median Value
Raw
136.0
110.9
3»9
111.9
0.11
0.02
115.8
7.8
4.8
4.0
137.4
59.9
431.0
15.5
129.6
Surg
140
114
-
-
-
-
-
7
5
4
2626
70
1245
39
-
e
.4
.6
.4
.1
.0
.0
.0
.0
.0
Prim.
140.
95.
17.
103.
0.
0.
121.
8.
3.
3.
110.
51.
908.
34.
198.
4
8
9
8
11
02
7
2
8
3
5
3
0
9
0
Sec.
129.6
19.0
41.4
80.4
0.29
0.13
121.9
7.5
1.5
3.1
35.6
60.9
551.0
13.3
156.8
Tert.
162.5
12.8
-
-
-
-
-
7.4
1.0
0.8
9.7
49.8
549.0
15.5
123.3
Filt.
-
11.
-
-
-
-
-
7.
0.
0.
7.
45.
534.
17.
122.
6
4
9
7
0
7
0
4
8
Final Upstream
166
2
4
17
0
0
21
7
0
0
6
42
559
17
116
.5
.4 16.3
.0
.0
.14
.04
.1
.4
.7 1.5
.6 1.6
.3 6.3
.4 49.2
.0
.4
.1
Downstream
_
9.4
-
-
-
-
-
-
1.6
1.9
12.8
49.3
-
-
_
-------
MAY 1974 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
136
102
6
31
0
0
58
7
5
4
148
59
730
19
249
.3
.7
.4
.3
.23
.04
.0
.5
.4
.8
.9
.7
.0
.9
.3
Surg
145
123
-
-
-
-
-
7
5
4
-
85
1245
55
138
e
.7
.1
.8
.3
.7
.8
.0
.0
.9
Prim.
145.7
90.9
6.9
36.3
0.23
0.03
43.2
8.9
4.1
3.5
179.0
66.8
733.0
17.6
406.2
Sec.
169.0
18.1
23.7
27.2
0.43
0.20
50.8
7.6
1.6
3.0
29.5
59.9
743.0
18.2
331.4
Tert.
206.0
7.3
-
-
-
-
-
7.3
1.1
0.8
6.2
54.3
710.0
19.9
135.6
Filt.
-
5.8
-
-
-
-
-
7.3
1.2
0.7
4.3
49.8
696.0
15.9
129.8
Final Upstream
220.
4.
3.
7.
0.
0.
10.
7.
0.
0.
3.
54.
710.
15.
123.
4
6 12.4
2
7
43
19
9
3
9 1.3
5 0.9
2 3.2
0 62.5
0
9
9
Downstream
—
11.1
-
-
-
-
-
-
1.3
1.0
12.9
50.9
-
-
_
*Median Value
-------
JUNE 1974 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
388.8
138.1
7.3
96.3
0.12
0.02
103.5
7.4
4.8
4.8
128.8
66.2
958.0
23.9
291.3
Surge
429.8
137.6
-
-
0.02
0.00
-
7.6
4.8
4.6
3938.0
75.6
1520.0
35.1
390.0
Prim.
429.8
96.8
10.2
72.4
0.18
0.03
82.6
8.3
4.1
3.5
179.0
66.8
733.0
17.6
406.2
Sec.
430.4
18.0
25.9
49.4
1.37
0.18
75.3
6.9
1.6
1.2
17.2
69.4
1006.0
24.1
—
Tert.
340.0
8.4
-
-
0.04
0.02
-
6.7
0.7
1.0
4.4
58.8
792.0
23.9
_
Filt.
-
4.7
-
-
-
0.20
-
7.1
0.9
0.8
2.6
68.5
784.0
23.9
-
Final
435.0
2.3
3.4
2.1
0.63
0.07
5.7
6.7
0.8
0.7
1.8
60.2
771.0
23.9
-
Upstream
—
14.1
-
-
0.04
-
-
-
1.6
1.6
1.8
59.7
300.0
34.3
-
Downstream
_
14.4
-
-
0.04
-
-
-
1.6
1.6
38.8
51.9
446.0
28.9
-
^Median Value
-------
JULY 1974 DATA
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
384.0
144
8
80
0
0
88
7
6.
6.
168.
87.
864.
10.
205.
.7
.0
.0
.15
.02
.0
.5
.8
,7
,6
2
0
1
0
Surge
364.0
137.6
-
-
0.02
0.00
-
7.6
4.8
4.6
3938.0
75.6
1520.0
35.1
390.0
Prim.
337.0
102.2
14.3
64.0
0.30
0.04
78.0
7.8
6.1
5.9
30.9
76.0
765.0
18.8
218.0
Sec.
386.0
14.1
19.3
55.0
0.69
0.21
79.0
7.2
6.4
2.2
16.0
58.7
823.0
13.7
222.0
Tert.
335.0
2.8
-
-
0.59
0.11
-
6.8
1.5
1.5
6.6
54.8
813.0
10.1
183.0
Filt.
_
2.7
-
—
0.45
0.07
-
7.1
1.1
1.5
4.9
40.1
781.0
11.0
171.0
Final
368.0
2.1
2.8
6.0
0.39
0.06
5.7
6.7
0.8
0.7
1.8
60.2
771.0
23.9
_
Upstream
1.3
_
0.35
0.01
_
_
1.3
1.1
2.6
54.9
_
_
D OWD s I-T e> a m
2.
0.
0.
1.
1.
21.
54.
5
38
01
4
2
5
3
^Median Value
-------
AUGUST 1974 DATA
ho
M
LO
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
_
138.7
2.6
•
24.8
0.30
0.02
25.0
7.7
9.6
9.8
-
75.1
149.5
12.5
355.0
Surge
_
138.
-
-
0.
0.
-
7.
9.
9.
2253.
76.
-
-
_
3
28
04
8
5
8
0
7
Prim.
_
131.4
2.4
20.1
0.37
0.06
-
8.1
8.9
9.1
44.3
64.7
928.0
22.8
350.0
Sec.
100.4
18.6
8.2
15.8
1.05
0.20
-
7.1
2.4
2.3
24.9
67.1
937.0
17.4
90.0
Tert.
152.0
8.1
-
-
0.80
0.21
-
6.9
1.4
1.5
4.7
55.5
906.0
10.5
80.0
Filt.
—
6.2
-
—
0.60
0.12
-
6.7
1.2
1.2
2.1
55.0
833.0
50.8
40.0
Final
151.
5.
1.
2.
0.
0.
2.
6.
1.
1.
1.
55.
788.
50.
_
5
6
4
6
70
11
5
1
2
1
9
7
0
8
Upstream
_
6.9
_
-
0.48
0.03
-
-
1.6
1.3
2.1
66.3
-
-
_
Downstream
_
6
_
-
0
0
-
-
1
1
11
69
-
-
_
.7
.48
.03
.7
.5
.0
.3
*Median Value
-------
SEPTEMBER 1974 DATA
Downstream
6.3
Parameter
COD
BOD5
Org-N
NHs-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
Raw
578.6
145.4
2.7
22.1
-
0.03
24.8
7.9
7.3
6.5
-
-
-
37.3
_
Surge
624.0
162.2
-
-
0.11
0.03
-
7.3
8.6
7.6
1975.0
62.5
4338.0
46.4
_
Prim.
587.0
131.0
2.0
16.8
0.09
0.03
18.8
8.2
6.7
5.8
33.8
60.4
699.5
41.3
286.0
Sec.
303.2
23.4
5.6
13.8
0.77
0.36
18.1
7.4
2.3
1.8
30.8
66.7
676,0
22.8
280.0
Tert.
224.0
9.8
-
-
0.49
0.19
-
7.2
1.4
1.3
4.2
58.9
388.0
37.3
239.5
Filt.
-
7.1
-
-
0.70
0.11
-
7.2
0.94
1.15
3.4
53.6
800.0
36.6
229.0
Final
-
6.5
1.3
0.5
0.26
0.11
1.5
7.3
1.14
0.91
2.8
52.4
344.0
36.6
218.5
Upstrej
-
5.9
-
-
-
0.08
-
-
1.70
-
2.77
57.3
-
14.9
_
0.08
1.75
43.1
565.0
*Median Value
-------
OCTOBER 1974 DATA
Parameter Raw Surge Prim. Sec. Tert. Filt. Final Upstream Downs t ream
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
_ _
140.2 147.7
2.6
25.4
-
-
28.0
7.8 7.7
5.8 5.6
-
87.0 78.9
-
-
-
_ _
______
120.5 20.4 5.5 5.4 3.8 5.2
______
19.2 17.1 10.0 - 0.83
______
______
22.8 21.5 11.0 - 1.5
8.8 7.4 7.0 7.0 7.0 7.1
4.3 1.6 1.6 1.0 0.69 0.3
______
63.4 - 8.4 4.0 2.87 5.3
______
------
______
_
_
3.0
-
-
-
-
-
7.0
1.42
-
9.2
-
-
-
_
*Median Value
-------
NOVEMBER 1974 DATA
Upstream Downstream
Parameter
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
vss%
TS
TVS%
Alk.
Raw
128.
99.
3.
18.
0.
0.
21.
-
7.
-
107.
-
954.
50.
-
Surge
0
8
7
9
15 0.13
02 0.03
9
-
0 7.5
-
1 4339.0
-
0
9
-
Prim.
432.0
-
0.12
0.03
-
-
6.5
-
79.7
-
862.0
73.8
_
Sec.
464.0
-
0.72
0.13
-
-
1.1
-
24.5
-
809.0
66.7
_
Tert.
48.0
-
0.56
0.27
-
-
1.05
-
8.2
-
820.0
79.9
_
Filt.
-
-
0.32
0.22
-
-
1.15
-
3.5
-
799.0
66.1
_
Final
16.0
4.6
0.6
1.09
1.93
0.28
1.6
-
0.85
-
4.2
-
802.0
58.4
_
1.6 1.6
4.0 6.0
*Median Value
-------
DECEMBER 1974 DATA
Parameter Raw .Surge Pritn^ Sec. Tert. Filt. Final Upstream Downstream
COD
BOD5
Org-N
NH3-N
N02-N
N03-N
TKN
pH*
P Total
P St
SS
VSS%
TS
TVS%
Alk.
^Median Value
Raw
150.7
67.5
4.4
11.0
O.*14
0.02
15.4
7.1
6.8
56.5
77.9
117.5
78.2
186.7
Surge
112.0
123.8
-
-
0.07
0.11
-
7.0
7.0
547.9
58.7
1844.0
65.2
195.0
Prim.
181.3
87.8
2.9
8.8
0.8
0.02
11.7
6.3
6.3
95.1
63.4
556.0
74.4
238.3
Sec.
241.3
39.3
2.9
5.1
0.41
0.06
8.0
4.4
3.1
45.6
71.1
353.0
62.8
243.3
Tert.
315.6
11.9
-
-
0.52
0.03
-
4.4
1.0
11.7
73.5
306.5
46.8
188.3
Filt.
-
8.1
-
-
-
0.03
-
1.3
0.7
10.3
69.0
530.0
79.4
174.4
Final
345.6
1.3
1.3
4.0
0.50
0.12
5.3
0.65
0.60
3.5
63.8
331.5
81.3
164.0
-------
APPENDIX E
HATFIELD TOWNSHIP MUNICIPAL AUTHORITY
REVIEW PRESENT DESIGN FOR ABILITY TO ACHIEVE
ADDITIONAL NITROGENOUS BOD REMOVAL
DESIGN BASIS
Q - 3.6 mgd 13.626 x 1Q3 cu m/day
BOD5 = 7050 Lb/Day (235 mg/1) 3200.7 Kg/Day
SS - 7050 Lb/Day (235 mg/1) 3200.7 Kg/Day
NHs-N = 900 Lb/Day (30 mg/1) 408.6 Kg/Day
LOAD TO AERATION SYSTEM
BOD Removal Across Primary Treatment Units With Lime Addition
Estimated To Be 60%
.'. BOD5 To Aeration
0.4 (3201) - 1280 Kg
0.40 (7050) =• 2820 Lb. BOD5/Day
NH3'N To Aeration Estimated to be 67% of Influent NH3'N
(See: Systems for Phosphate and Nitrogen Removal, by O.E. Albertson,
presented at the 41st Annual Conference of Water Pollution Control
Association of Pennsylvania, University Park, Pennsylvania,
August 6, 1969)
0.67 (409 = 274 kg
0.67 (900) - Lb. NH3-N/Day
Aeration Tanks - Two (2) 15.2 m sq x 4.6 m
50' sq x 15' SWD
(1060 cu m each)
Detention Time @ QM71T
A.V ili
2120 cum =
13.6 cum/day/24 hr
218
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Aeration System Has Been Sized to Provide:
2052 kg 02/Day @
which is equivalent to:
3564 kg 02/Day @
*V I
B -
T =«
DO -
Elev -
t. ,
B -
T =-
DO =-
Elev -
0.8
0.95
25° C
2 mg/1
300'
1.0
1.0
20° C
Zero
Sea Level
Calculate Nitrification Completed at Winter Wastewater Temperature
if 10.75° C (~51° F) (After Downing)
BOD Loading Rate @ 4000 mg/1 MLSS
4000 r Vcr
-^p x 0.56(106) x 8.34 - MLSS x 0.454 -g =« 8489 kg MLSS
- 0.151 * BOB/kg MLSS
Assume Use of 0.95 kg 02/kg BOD Applied (@ 10.75° C) For
Metabolism (Into The Mixed Liquor)
For Nitrification Use 46 kg 02/kg NI^'N Applied (Into Mixed Liquor)
.'. Total 02 Required
BOD5 - 0.93 (1280) = 1190 kg 02/Day
NH3'N » 4.6 (274) = 1260 kg 0?/Day
£, = 2450 kg 02/Day
Into The Mixed Liquor
which is equivalent to:
4022 kg 02/Day @ ^ = 1.0
B = 0.95
T = 20° C
DO = Zero
Elev = Sea Level
219
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Apparent 02 Deficit
4022
-3564
458 kg 02/Day @ Standard Conditions
Or 279 kg 02/Day @ Design Conditions (10.75° C)
1260
- 279
981 kg 02/Day Available For Nitrification
981
1260
78% Nitrification
Calculate Nitrification Completed at Summer Wastewater Temperature
of 20° C (~77° F) (After Sawyer)
Use 0.175 gm NH3 Nitrified/Day per gm MLVSS
274 kg NHyN ,,
0.175 kg NH3-N/kg MLVSS = 1566 kg
Assume MLVSS - 0.75 MLSS
1566
MLSS
0.75
2088 kg MLSS
BOD Loading Rate
-|||| » 0.614 kg BOD/kg MLSS
Use 0.77 kg 02/kg BOD Applied For Metabolism (Into Mixed Liquor)
.'. Total 02 Required - BOD5 - 0.77 (1280) - 985.8 kg 02/Day
NH3-N - 4.6 (274) =« 1260.0 kg 02/Day
2245.8 kg 02/Day
Into The Mixed Liquor
which is equivalent to:
220
-------
3895 kg 02/Day @ * - 1.0
B = 0.95
T =•= 20° C
DO =« Zero
Elev =* Sea Level
Apparent 02
4022
-3895
127 kg 02/Day @ Standard Conditions
Or 72.2 kg 02/Day @ Design Conditions (25° C)
1260
- 72
1188 kg 02/Day Available for Nitrification
1188
1260
94.2% Nitrification
221
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APPENDIX F
GENERATION OF SLUDGES
A. CONVENTIONAL TREATMENT
Given:
Primary Efficiency
250 mg/1 x 8.34 x 1.0 x 0.6 =
Flow =
BOD5 =
TSS =
0.5 #WAS/#BOD5
60% TSS Removal
40% BOD5 Removal
1 mgd
200 mg/1
250 mg/1
200 mg/1 x 8.34 x 1.0 x 0.60 x 0.5 //WAS =
#BOD5
1,251 Lb/Day Primary
500 Lb/Day WAS
1,751 D.S./mg Flow
B. GENERATION OF SLUDGES FROM THE HATFIELD AWT FACILITY
Assumptions:
Primary Efficiency:
Flow= 1 mgd
BOD5 = 200 mg/1
TSS = 250 mg/1
P Total 10 mg/1
0.5 #WAS/#BOD5
420 mg/1 Ca(OH)2 to achieve pH 9.5
150 mg/1 Alum
80% TSS Removal
80% P Removal
60% BODs Removal
250 mg/1 x 8.34 x 1 mgd x 0.8 = 1668 Ib/day
222
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Chemical Sludges:
420 mg/1 Ca(OH)2 x 8.34 x 1.0 mgd = 3503 Ib/mg
3503 Ib/mg x 0.54 Ib. Ca++/Lb. Ca(OH)2 = 1892 Ib/mg Ca-H- fed
P Removed = 8 mg/1
8 mg/1 x 5.4 Lb. Ca5OH(P04)3/Lb. P x 8.34 x 1 mg = 360 Ib/mg
Ca5OH(P04)3
360 Ib/mg x 0.398 ' a = 133 Ib. Ca-H- consumed/mg
Lb . CaxPy
1892-133 = 1759 Ib/mg x 2.5 = 4400 Ib/mg CaC03
Secondary Treatment :
200 mg/1 BODr x 0.4 x 0.5 ' x 8.34 = 330 Ib/day WAS
D Lb . BOD5
Tertiary Treatment:
Alum Fed: 150 mg/1 x 8.34 x 1.0 mgd = 1251 Ib/day
1251 Lb. A12S04 • 16 HoO x 54 Lb. A1+3 - .= 101.3 Lb. A1+3 Fed
z Lb. A12 (S04)3 -14 H2°
P Removed =2.0 mg/1
2.0 mg/1 Px x 8.34 x 1.0 mgd - 16.7 Ib/mg
16.7 Ib/mg x 0.87 Lb. Al/Lb.P = 14.5 Lb. Al+3 Consumed
101.3-14.5 = 86.8 Lb. Al+3/mg x 78/27 = 250 Ib/mg as A1(OH)3
14.5 Lb. Al+3 x 188/27 = 101 Ib/mg A1(P04) • 2H20
Sludge Summary:
*
Primary Sludge 1,668 Ib/day
CaC03 4,400
Ca5OH(P04)3 360
WAS 330
A1(OH)3 plus Al P04 351
7,109 Ib/day D.S./mg flow
223
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-75-030
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
HATFIELD TOWNSHIP, PENNSYLVANIA, ADVANCED WASTE
TREATMENT PLANT
September 1975 (Issuing Date)^
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Tracy W. Greenland and Fred R. Gaines
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Hatfield Township Municipal Authority, Advance Lane,
Colmar, Pennsylvania 18915
Through subcontract with
Tracy Engineers, Inc., Camp Hill, Pennsylvania 17011
10. PROGRAM ELEMENT NO.
1BB043 (ROAP 21-ASO;Task 046~)
11. CONTRACT/GRANT NO.
11060 FRQ
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final 1970-1974
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The Hatfield Township, Pennsylvania, Water Pollution Control Plant was designed to
encompass primary chemical treatment, secondary combined activated sludge and nitri-
fication facilities, tertiary chemical tube clarification and mixed media filtration.
The operation of the facility demonstrated that the use of flow equalization facili-
ties improves plant operations by reducing and standardizing chemical concentrations.
Phosphorus is removed efficiently in a combined primary-tertiary phase with operations
personnel having the flexibility to optimize each process. Lime feed control by pH
is easily accomplished, although recirculation of primary sludges is not always
necessary. Tube clarifiers and mixed media filters combine to produce a highly pol-
ished effluent. Nitrification was observed to some extent in this modified facility,
however, it was extremely difficult to control.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Waste water*, Activated sludge process,
Nitrification, Filtration*, Phosphorus
Phosphorus control,
Effluent standards,
Lime coagulation, Alum
precipitation, Tertiary
treatment*, Flow equali-
zation
13B
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS
Unclassified
TIM Report}
20. SECURITY CLASS (Thispage)
Unclassified
21. NO. OF PAGES
236
22. PRICE
EPA Form 2220-1 (9-73)
224
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INSTRUCTIONS
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EPA Form 2220-1 (9-73) (Reverse) £USGPO: 1975 — 657-695/5303 Region 5-1
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