EPA-600/2-76-082
MARCH 1976
Environmental Protection Technology Series
Do not remove. This document
should be retained in the EPA
Region 5 Library Collection.
TERTIARY TREATMENT FOR
f HOSPHOROS REMOVAL AT
ELY, MINNESOTA AWT PLANT
APRIL, 1973 THRU MARCH, 1974
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-76-082
March 1976
Yl
' TERTIARY TREATMENT FOR PHOSPHORUS REMOVAL
XJ AT ELY, MINNESOTA AWT PLANT
April, 1973 thru March, 1974
d
f
J by
3,
John W. Sheehy
Francis L. Evans, III
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
Grant No. S-802309
Project Officer
Robert M. Brice
Shagawa Lake Research Project
Environmental Research Laboratory
Corvallis, Oregon 97330
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevar.d, 12th Floor
Chicago, !L 60604-3590
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research Labora-
tory, U.S. Environmental Protection Agency, and approved for publication.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
11
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FOREWORD
The Environmental Protection Agency was created because of increasing public
and government concern about the dangers of pollution to the health and welfare
of the American people; Noxious air, foul water, and spoiled land are tragic
testimony to the deterioration of our natural environment. The complexity of
that environment and the interplay between its components require a concen-
trated and integrated attack on the problem.
Research and development is that necessary first step in problem solution and
it involves defining the problem, measuring its impact, and searching for
solutions. The Municipal Environmental Research Laboratory develops new and
improved technology and systems for the prevention, treatment, and management
of wastewater and solid and hazardous waste pollutant discharges from municipal
and community sources, for the preservation and treatment of public drinking
water supplies, and to minimize the adverse economic, social, health, and
aesthetic effects of pollution. This publication is one of the products of
that research; a most vital communications link between the researcher and
the user community.
This report shows that an effectively operated advanced wastewater treatment
facility can reliably and continuously reduce total phosphorus to a very low
concentration and in this way enhance the quality of the receiving body of
water.
Louis W. Lefke
Acting Director
Municipal Environmental Research Laboratory
111
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ABSTRACT
This report documents the first 12 months of continuous operation of the 1,5
mgd Ely tertiary wastewater treatment plant which reliably removed 99% of the
influent total phosphorus and discharged an extremely low effluent total
phosphorus concentration, averaging 0.045 mg/1, The tertiary treatment
facility, consisting of flow equalization two-stage lime clarification, dual-
media filtration and chlorination, was designed to reduce total phosphorus
concentration in the existing trickling filter plant effluent to 0.05 mg/1.
Operational costs for the tertiary plant averaged $0.24/m3 ($0,91/1000 gallons)
However, it is estimated that the facility could have been operated to achieve
an effluent phosphorus concentration of 1 mg/1 for approximately $0.13/m3
($0.50/1000 gallons),
This report includes performance data, operational data, maintenance require-
ments, and operating costs for the Ely AWT facility from April, 1973 through
March, 1974. The report presents a thorough discussion of phosphorus per-
formance data along with pertinent information on suspended solids, turbidity,
TOG, calcium and iron removal. The report also includes a discussion of
sludge treatment processes including data such as sludge volumes, vacuum
filter yields, and sludge dryness. Operating data described includes waste-
water flow, chemical dose, pH, clarifier solids volume and gravity filter
head loss. The report further describes routine maintenance and manpower
requirements, including major equipment breakdowns and repairs. Operating
costs are divided into five categories and 27 sub-categories. The five cost
categories are personnel, chemicals, utilities, laboratory and miscellaneous
supplies, and equipment operation and repair.
IV
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CONTENTS
Page
Foreword m
Abstract •
List of Figures vii
List of Tables
-LyC
Acknowledgements
JC
Sections
I Summary and Conclusions 1
II Recommendations 4
III Introduction 5
IV Process Description 10
A. Primary and Secondary Facilities
B. Tertiary Treatment Unit Processes
C. Appurtenant Equipment
D. Analytical Program and Sample Scheduling
V Process Performance iq
A. Secondary Plant
B. Tertiary Plant
1. Two-Stage Lime Clarification
2. Dual-Media Filtration
C, Summary of Tertiary Plant Performance: Plant Reliability
and Effluent Variability
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Page
VI Sludge Treatment and Disposal 47
A. Sludge Handling
B. Sludge Thickener Influent Characteristics
C. Tertiary Thickener Performance
D. Vacuum Filtration and Landfill Disposal
VII Operation and Maintenance 56
A. Personnel Organization and Tasks
B. Plant and Equipment Problems
C. Maintenance Requirements
VIII Costs of Operation and Maintenance 65
IX References 69
X Appendices
A. Treatment Plant Layout Plans and Design Criteria 70
B. Schematics of Liquid and Sludge Flows 82
C. Secondary Plant Data 89
D. Tertiary Plant Data Summary: April, 1973 thru March, 1974 92
E. Total Phosphorus Data: April, 1973 thru March, 1974 102
F. Distribution of Operation and Maintenance Costs 116
VI
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FIGURES
No. Page
3-1 Shagawa Lake Restoration Project Site 7
4-1 Flow Diagram of Ely Secondary Wastewater Treatment Plant 11
4-2 Flow Diagram of Ely Tertiary Wastewater Treatment Plant 13
5-1 Monthly Average Values of Influent Alkalinity, Lime Dose,
Clarifier pH, and Effluent Total Phosphorus for First-Stage
Lime Clarifier 20
5-2 Influence of Upper Mix Zone Solids Volume on Total Phosphorus
Removal in First-Stage Lime Clarifier 22
5-3 Monthly Average Values of Upper Mix Zone Solids Volume, Percent
Total P Removal, and Total P Concentration in Second-Stage Lime
Clarifier Effluent 23
5-4 Influence of Iron Dose on Total Phosphorus Removal in Second-
Stage Lime Clarifier 26
5-5 Influence of Tertiary Plant Flow on Total Phosphorus Removal
by First and Second-Stage Effluent 28
5-6 Monthly Average Suspended Solids in First-Stage Influent,
First-Stage Effluent, and Second-Stage Effluent 30
5-7 Monthly Average Concentrations of Suspended Solids, Turbidity,
Particulate Phosphorus and Total Phosphorus in Second-Stage
Clarifier Effluent 32
5-8 Effect of Hydraulic Loading on Total Phosphorus Removal by
Dual-Media Filtration 37
5-9 Variability of Total Phosphorus in Second-Stage Clarifier
Effluent and Filter Effluent April 1, 1973 to March 31, 1974 42
5-10 Variability of Turbidity in Second-Stage Clarifier Effluent and
Filter Effluent, April 1, 1973 to March 31, 1974 43
5-11 Variability of Suspended Solids in Second-Stage Clarifier
Effluent and Filter Effluent, April 1, 1973 to March 31, 1974 44
VII
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N£. Pag<
5-12 Monthly Values of Coefficient of Variation for Total Phos-
phorus Removal by Each Tertiary Unit Process and by Tertiary
Treatment System 45
6-1 Monthly Averages of Feed Solids Concentration, Filter Yield,
and Drum Speed for Vacuum Filtration of Lime Conditioned
Combined Biological-Chemical Sludge 54
Vlll
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TABLES
No. Page
4-1 Analytical Sampling and Analysis Schedule 18
5-1 Total TOC Removal by Tertiary Lime Clarification 33
5-2 Particulate and Soluble Phosphorus Removal by
Dual-Media Filtration 36
5-3 Gravity Filter Performance 38
5-4 Total Phosphorus Removal Summary -
April, 1973 thru March, 1974 41
6-1 Biological and Chemical Sludge Flows to Tertiary
Sludge Thickener 48
6-2 Chemical Sludge Characteristics 50
6-3 Tertiary Sludge Thickener Overflow Characteristics 52
6-4 Vacuum Filtration of Combined Biological and Chemical
Sludges 53
7-1 Manpower Requirements for Ely AWT Plant 62
8-1 Operation and Maintenance Costs for Ely Wastewater Treatment
Plant - April, 1973 thru March, 1974 66
8-2 Unit Costs of Chemicals and Power for Ely AWT Plant
Operation 67
IX
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ACKNOWLEDGEMENTS
The construction and operation of the Ely AWT Plant was supported by the U.S.
Environmental Protection Agency's Office of Research and Development for the
City of Ely, Minnesota under the administration of the Honorable J. P. Grahek,
Mayor.
The overall planning and execution was urider the general direction of Mr.
Robert M. Brice, EPA Project Officer for the Shagawa Lake Research Project.
The operation of the Ely AWT plant depended on the efforts of numerous indi-
viduals. Thanks are extended to these and especially to Glen Lindroos, City
of Ely, for providing much of the background data on the operation and main-
tenance of the existing trickling filter plant and to Robert Randall, EPA, for
supervising the chemistry laboratory where myriad analytical determininations
were required. Particular thanks are extended to the twelve EPA operating
personnel who in no small way contributed to the successful performance of
the Ely AWT plant.
Appreciation is also expressed to Dr. R. L. Bunch, Messrs. Richard Brenner,
J. M. Smith and James J. Westrick of the Municipal Environmental Research
Center in Cincinnati Ohio, who provided program guidance and assistance in
the conduct of this study.
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SECTION I
SUMMARY AND CONCLUSIONS
1. The costs required to operate the Ely Wastewater Treatment Plant from
April 1, 1973 through March 31, 1974 were $389,107.64. During this period
1.6 x 106m3 (427.7 million gallons) of wastewater were treated at a cost of
$0.24/m3 ($0.91/1000 gallons).
2. For the one-year period of operation from April 1, 1973 to March 31,
1974 the tertiary facilities at the Ely AWT plant performed as follows:
Parameter
(mg/1)
BOD
TOC
Suspended Solids
Turb.-JTU
Soluble P
Particulate P
Total P
2-Stage Lime
INF
46
Clarification Dual-Media Filtration
EFF* %
70**
23
2.
1.
4.
68
88
56**
18
7.
2.
0.
0.
0,
1
0
033
050
083
Removal INF*
61
90
91
99
97
98
19.
8.
2.
0.
0.
0.
5
7
22
038
051
089
EFF % Removal
12.
17.
1.
0.
0.
0.
0.
3
9
3
56
037
008
045
.
8
85
75
3
84
49
Removal in
Tert. Pit
_
61%
98%
98%
98.6%
99.6%
99.0%
* The difference between the clarifier effluent values and the filter influ-
ent values was due to the chemical reactions resulting from sulfuric acid and
ferric chloride additions which were made between the sampling points in the
second-stage clarifier overflow and the dual-media filters' splitter box.
** The tertiary plant influent values were greater than the secondary plant
effluent values due to high solids and phosphorus in the waste flows which
were returned to the head of the tertiary plant.
3. Tertiary plant recycle streams returned to the head of the high-rate
trickling filter secondary treatment facilities most likely improved the
performance of the secondary treatment facilities. For the one-year period
of operation from April 1, 1973 to March 31, 1974 the secondary treatment
facilities achieved the following performance.
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BOD
Suspended Solids
Total Phosphorus
Influent
(mg/1)
90
202
7.07
Effluent
(mg/1)
39
44
3.81
Reduction
57
78
46
4. The 208 m3 (55,000 gallon) wet well of the tertiary influent pump station
was used as an equalization tank. In addition to secondary effluent flow to
the influent tank consisted of six sample waste streams and clarifier over-
flows. The tertiary influent tank, together with the manually operated pump
controller, served to dampen hydraulic variations. Steady flows could be
maintained for periods of time varying from one to eight hours, resulting in
improved tertiary plant operation.
5: The first-stage lime clarifier removed an average of 93.5 percent of the
total influent phosphorus in 12 months of continuous operation The monthly
median clarifier pH values varied from 11.84 to 12.07. The performance of the
first-stage clarifier was related to the solids inventory carried in the mix-
ing zone which in turn was determined by the speed of the turbine mixer.
6. The second-stage lime clarifier operated at a pH of 9.6 +_ 0.1 and removed
an average of 72.2 percent of the second-stage influent total phosphorus.
Through two-stage clarification, total phosphorus removal averaged 98 percent.
The addition of 3-6 mg/1 iron (as Fe ) to the second-stage clarifier quali-
tatively improved coagulation/flocculation and enhanced the removal of phos-
phorus .
7. The removal of soluble phosphorus, particulate phosphorus, and total phos-
phorus through dual-media gravity filtration averaged 3 percent, 84 percent
and 49 percent, respectively. The mean filter effluent suspended solids was
less than 2 mg/1, and the mean effluent turbidity averaged 0.6 JTU. The
adjustment of the filter influent pH to 7-8 prevented, deposition of CaCO, on
the filter and the addition of 2-4 mg/1 iron (as Fe+3) minimized the disso-
lution of particulate phosphorus. Filter runs up to 24 hours and hydraulic
loadings up to 8.6 m/hr (3.5 gpm/sq ft) were achieved.
8. Sludge solids loading to the gravity thickener averaged 2780 kg/day (6130
Ibs/d^y) of combined biological-chemical sludge at an average daily flow of
109 m /day (28,760 gpd). Of the total flow 12 percent was undigested combined
raw and secondary sludge from the trickling filter plant at 7-10 percent solidsj
62 percent was first-stage lime clarifier underflow at 0.8-1.0 percent solids;
and 26 percent was second-stage lime clarifier underflow at 2.1 percent solids.'
Thickener underflow solids concentration averaged 15 percent. Sludge handling
problems encountered were(a) high solids in the thickener overflow which was
due to poor settling characteristics of the undigested combined raw and
secondary sludges and (b) odors caused by processing undigested sludge from
the secondary plant.
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9. Prior to vacuum filtration, thickener underflow was conditioned with lime
at the average rate of 33 gm/kg (66 Ibs/ton) of dry solids. At an average
loading of 47.0 kg/nr/hr (9.6 Ibs dry solids/sq ft/hr) the filter cake con-
tained greater than 30 percent solids 95 percent of the time, and averaged
35.7 percent solids for a ten month period. Conditioning sludge with lime
increased the filter yield by 81 percent from an average of 27.0 kg/m2/hr
(5.6 Ibs/sq ft/hr) to an average of 49.0 kg/m2/hr (10.0 Ibs/sq ft/hr).
10. Operation of the secondary and tertiary facilities at the 5678 m /day
(1.5 mgd) Ely AWT plant required an operating staff of 15-16 persons plus 3-4
laboratory personnel. Four shifts of two men each operated the tertiary
facilities. While the vacuum filter was in operation, the full-time attention
of one operator was required. In addition to routine maintenance, consider-
able time and money were expended for corrective maintenance of the comminutor,
secondary bioligical clarifier, second-stage lime clarifier, sludge thickener,
and sludge underflow pumps. Additional time was spent to improve safety
conditions within the plant buildings and around the grounds,
Based on the operation of the 5678 m /day (1.5 mgd) Ely AWT plant, it is esti-
mated that operation of a similarly designed 37,850 m^/day (10 mgd) plant
would require an operating staff of 18 to 20 persons plus 3-4 laboratory
personnel.
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SECTION II
RECOMMENDATIONS
1. Long term operation of the two-stage lime clarifier indicated that per-
formance of the process with respect to clarifier effluent phosphorus and
suspended solids concentrations was related to effluent turbidities. Auto-
matic turbidity measurements with continuous read-out is suggested for both
first and second-stage lime clarification process monitoring,
2. Performance of the sludge thickener was adversely affected in direct pro-
portion to the amount of undigested combined raw and secondary sludge in the
thickener. Poor settling characteristics of this sludge increased solids in
the thickener overflow and decreased underflow solids concentration. The
short-term use of a polymeric flocculant aid improved thickener performance
and is suggested for continuous use,
3. Prior to plant start-up, safety training for supervisors and operating
personnel should be provided because of the potential hazards which are
associated with complex treatment equipment and chemical us.age.
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SECTION III
INTRODUCTION
The Shagawa Lake Restoration Project in Ely, Minnesota is a field activity of
the Eutrophication and Lake Restoration Branch of EPA's Environmental Research
Laboratory, Corvallis, Oregon. The Project is being carried out in coopera-
tion with the Wastewater Research Division of EPA's Municipal Environmental
Research Center in Cincinnati Ohio which has assumed primary responsibility
for operation of the tertiary wastewater treatment plant. The objective of
the project is the demonstration of the feasibility of improving the quality
of a culturally eutrophic lake by removing phosphorus from the Ely municipal
wastewater treatment plant effluent, the primary source of nutrient supply to
that lake.
Eutrophication is the process whereby a body of water is enriched with aquatic
plant nutrients to concentrations which result in nuisance levels of biological
activity. During early stages of evolution, lakes are typically low in bio-
logical productivity and high in purity. As lakes age, biological productivity
increases first through levels that are optimal for the propagation of desir-
able game fish but eventually levels are reached which result in a lowering of
water quality to the point that a lake no longer provides adaauate habitat for
desired species. In the final stages of evolution, they often undergo periods
of low oxygen content, may possess undesirable tastes and odors, and develop
recurring nuisance algal blooms. Lakes thus may lose their aesthetic proper-
ties, may become unacceptable as a source of water supply, and may become
relatively useless for fishing, boating or swimming.
Natural eutrophication is generally a slow process requiring hundreds or thou-
sands of years for objectionable water characteristics to develop. Cultural
eutrophication, however, which is due to man's activities, proceeds much more
rapidly. A major cause of cultural eutrophication is the discharge of muni-
cipal wastes to a body of water. Such discharges greatly increase the flow of
nutrients to the body of water drastically accelerating the eutrophication
process.
Cultural eutrophication is a major environmental problem. The concern of sci-
entists and demands for remedial action have prompted investigations of tech-
niques to reduce the productivity of culturally eutrophic lakes and to restore
them to higher purity. Pilot or full-scale demonstrations have shown that
diversion of wastewater effluent around a lake, in situ chemical treatment of a
lake to precipitate nutrients, and dredging and aeration may be useful lake
restoration techniques. Another technique, nutrient removal from wastewater
entering a lake, appeared technically feasible. However, prior to initiation
of the Shagawa Lake Project, its effectiveness had not been demonstrated.
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Ely, Minnesota, which has a population of 5,000 persons, is located in north-
eastern Minnesota, about 160 km (100 miles) north of Duluth. Shagawa Lake,
shown in Figure 3-1, is located adjacent to the City of Ely. It was formed,
along with many other lakes in the region, during the retreat of the Wisconsin
Glacier approximately 10,000 years ago. The lake has a surface area about 970
hectares (2397 acres), a maximum depth of 14 meters (46 ft) and an average
depth of about 6 meters (20 ft). Burntside River, which flows out of oligo-
trophic Burntside Lake, is the major contributory, entering Shagawa Lake from
the west. Several smaller tributaries flow into the lake on the southwest and
the north. The only outlet is the Shagawa River on the eastern side of the
lake.
There are few natural sources of algal growth-promoting nutrients, and the
high productivity of Shagawa Lake has been attributed to the nutrients in the
municipal wastewater which has been discharging into the lake since prior to
1900. The City employed primary wastewater treatment until 1954 when a high-
rate trickling filter and secondary settling facilities were installed. Dur-
ing the period when secondary treatment plant effluent was being discharged
to the lake, studies have shown that about 80 percent of the phosphorus enter-
ing the lake through surface flows came from this source. About one percent
of the surface flow has been attributed to municipal wastewater and about 75
percent to Burntside River.
A number of factors influenced the selection of Shagawa Lake as the site for
demonstrating the restoration of a eutrophic lake by phosphorus removal from
a wastewater treatment plant effluent. (1) Shagawa Lake has had a history of
nuisance algal blooms. (2) The lake water quality is of particular concern
because its outflow passes through parts of the Superior National Forest, a
National Wilderness Area (Boundary Waters Canoe Area) and Canada. (3) The
eutrophic state of the lake was uncommon among the lakes in the area. (4) The
major surface flow of water into Shagawa Lake is high purity water and the
calculated hydraulic retention time in the lake is very short - about nine
months. (5) Municipal wastewater was the major source of nutrients to the
lake, there being no significant agriculture or industrial activity in the
area.
The Shagawa Lake Restoration Project was initiated on a pilot plant scale in
Ely, Minnesota in 1966. A 106 HP/day (28,000 gpd) tertiary wastewater treat-
ment plant processed effluent from the Ely municipal secondary (high-rate
trickling filter) wastewater treatment plant. Using isolated test basins
floating in the lake, the tertiary effluent was evaluated relative to algal
growth potential. Concurrently, a limnological investigation was carried out
to document the trophic state of the lake and to provide characterization for
comparison of "before" and "after" quality. Results of the study have been
published (1).
The tertiary wastewater treatment pilot plant included chemical clarification,
multi-media filtration, carbon adsorption, and ion exchange. In these early
studies, both lime and alum clarification followed by settling and filtration
reduced the total residual phosphorus concentration to less than 0.05 mg/1.
Carbon adsorption and ion exchange were not necessary in achieving the low
residual phosphorus concentrations.
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SHAGAWA LAKE
BURNTSIDE
RIVER
970 Hectares
(2397 Acres)
WASTEWATER
TREATMENT PLANT
STINKY !__w
SHAGAWA LAKE
ST. LOUIS COUNTY,
MINNESOTA
-T
'
KILOMETERS
0 0.5 1.0
SCALE
FIGURE 3-1. SHAGAWA LAKE RESTORATION PROJECT SITE.
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The use of floating basins as "receiving ponds" for the tertiary effluent
isolated segments of the lake and permitted evaluation of the pilot plant
effluent in a simulated lake environment. The basin tests demonstrated that
the tertiary treatment system substantially reduced the potential of the efflu-
ent to produce algal blooms when mixed with Shagawa Lake water or Burntside
River water.
Based upon the positive results of these pilot studies, the Environmental
Protection Agency considered a demonstration study for a tertiary wastewater
treatment system in order that full-scale restoration of Shagawa Lake could be
studied. The rate and extent of recovery of the lake would be documented and
limnological studies would continue for several years. Background data de-
scribing biological, physical, and chemical characteristics of the lake had
already been developed. These data would be used in determining the validity
of several mathematical models to be developed in an attempt to describe the
eutrophication process, and to simulate the lake water quality improvement
expected to result from tertiary phosphorus removal from secondary effluent.
In 1971, a Research and Development grant was awarded by the EPA to the City
of Ely, Minnesota to design a tertiary wastewater treatment facility. The
primary objectives of this grant were the following:
1. To develop a complete set of engineering plans and specifications for a
tertiary wastewater treatment system to remove phosphorus from secondary efflu-
ent to a residual of 0.05 mg/1 of total phosphorus or less.
2. To build into the design of the phosphorus removal facilities the capabil-
ity for upgrading the effluent quality to meet the State of Minnesota BOD and
suspended solids standards. The standards proposed by the State for Ely's
effluent discharge, which would guide the design of the proposed facilities,
were 25 mg/1 BOD5 and 30 mg/1 suspended solids.
3. To develop sound engineering estimates for construction and operating
costs for the proposed facilities. The construction cost estimates were to be
sufficiently detailed so that the cost of the phosphorus removal facilities
could be considered apart from the cost of repairs to the existing plant.
Likewise, operating costs were to be estimated separately for both the second-
ary trickling filter plant and the tertiary phosphorus removal facility.
The City of Ely engaged the architectural-engineering firm of Toltz, King,
Duvall, Anderson and Associates, Inc., St. Paul, Minnesota, to carry out the
design objectives. Plans and specifications for the AWT plant were completed
in June of 1971.
In this same year funds for construction and operation of the tertiary waste-
water treatment facility and for renovation of the existing high-rate trick-
ling filter plant were provided by two EPA grants totalling $2,572,358.
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The six primary objectives of the construction-operation grant are listed
below:
1. Construct tertiary wastewater treatment facilities which would remove phos-
phorus from the effluent of the typical high-rate trickling filter plant at
Ely, to a residual of 0.05 mg/1 of total phosphorus or less.
2. Demonstrate that the effluent from the upgraded facility could meet an
effluent BOD standard of 25 mg/1 and a suspended solids standard of 30 mg/1
as proposed by the State of Minnesota.
3. Begin construction of tertiary wastewater treatment facilities not later
than September I, 1971, and complete construction and have facilities ready
for "start'up" and "shake-down" by May 31, 1972.
4. Repair and restore the existing conventional wastewater treatment facili-
ties at Ely by July 31, 1972.
5. Provide facilities to return to the headworks of the existing conventional
treatment facilities for subsequent treatment, the maximum practicable amount
of runoff which drains into a channel known as "Stinky Ditch" from adjacent
hillsides and which for many years flowed untreated into Shagawa Lake.
6. Operate the combined wastewater treatment complex to a high degree of
efficiency with maximum practicable removal of phosphorus, BOD, and suspended
solids for a continuous period of three years commencing on or around August 1,
1972, while concurrent limnological studies are conducted on Shagawa Lake.
Completion of construction was delayed until December 1972 because of adverse
weather and labor strikes. Debugging and shakedown took about three months
and the tertiary facility was put into operation on April 1, 1973.
Because of the unpredicted delays in completion of construction and start-up,
the grant period was subsequently extended to January 31, 1976.
Although this construction-operation grant provided for construction, utility
costs, chemicals, fuel, supplies, etc., it did not provide funds for operating
personnel. Therefore, the Wastewater Research Division of the Municipal
Environmental Research Center, Cincinnati provided funding for an engineer-
superintendent, twelve plant operators, and four laboratory technicians.
The laboratory technicians are part of an analytical laboratory staff that
does all analytical work including that required for operation, for evaluation
of the plant, and for the limnological studies.
All other project personnel, laboratory supplies, administrative services, and
incidental costs not provided under the grant, or from MERL-Cincinnati were
provided by the Environmental Research Center in Corvallis, Oregon.
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SECTION IV
PROCESS DESCRIPTION
A. Primary and Secondary Facilities
The 5678 m3/day (1.5 mgd) high-rate trickling filter plant consists of a grit
chamber, trash rack, primary clarifier, trickling filter, secondary clarifier,
chlorine contact chamber, and a high-rate anaerobic sludge digester. The sec-
ondary plant is shown schematically in Figure 4-1 and the design criteria are
given in Table A-l.
The grit chamber is 10 m (32.5 ft) long x 1 m (3 ft) wide x 1.2 m (4 ft) deep.
It is equipped with a proportional weir which maintains a constant flow rate
of 0.30 m/s (1 fps) through the grit chamber. The comminutor, with 9.5 mm
(3/8 in) horizontal slots, screens and shreds large solids into smaller parti-
cles prior to further treatment. The comminutor was designed for a flow of
5678 m-Vday (1.5 mgd) with a peak capacity of 263500 m3/day (7.0 mgd).
The primary clarifier has a diameter of 15.2 m (50 ft) and a sidewater depth of
2.4 (7 ft 10 in). At the design flow of 5678 m3/day (1.5 mgd) the clarifier
detention time is 2 hours, the overflow rate is 31 m/day (760 gpd/sq ft) and
the weir overflow rate is 128 m2/day (10,270 gpd/lf). The primary clarifier is
equipped with mechanical scraper arms for sludge removal. Primary clarifier
underflow, which consists of primary sludge and recirculated secondary sludge,
is conveyed to the tertiary thickener by a piston pump. Floatable material in
the primary clarifier, which includes recirculated scum from the secondary
clarifier, is collected in a scum box and discharged for further treatment and
disposal. The solids handling facilities for the secondary and tertiary treat-
ment units are described later.
After primary settling, the sewage passes through a high-rate, stone media
trickling filter that is 18 m (60 ft) in diameter and 1.8 m (6 ft) deep. The
hydraulic loading at 5678 m3/day (1.5 mgd) is 22 m/day (23 mgad) and the organic
loading is 780 kg BOD/day/1000 m3 (49 Ibs BOD/day/1000 cu ft). Although the
trickling filter was designed for recirculation, this method of operation is not
used due to hydraulic limitations of the bypass Control Box #1 which is located
between the primary clarifier and trickling filter.
The secondary clarifier is 15.2 m (50 ft) in diameter, and has a sidewater depth
of 2 m (6 ft 10 in). At a plant flow of 5678 m3/day (1.5 mgd) the clarifier
has a detention time of 1.77 hours, an overflow rate of 31 m/day (760 gpd/sq ft)
and a weir overflow rate of 128 m2/day (10,270 gpd/lf). The secondary clarifier
10
-------
Grit Bar
Chamber Screen
Bypass Bypass Bypass
_ . Control _ . ... Control c , Control
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Recirculation
Pump Station
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Supernatant! i
Secondary Sludge
Pump Station
I ISupernatc
Sludge
Digester
Wet Wellt
#3 u
Tr
J!
Sand Drying Beds
LEGEND
Wastewater Piping
—•——• Sludge Piping
Scum Piping
Sludge Tank Truck
Holding Tank Loading Area
FIGURE 4-1. FLOW DIAGRAM OF ELY SECONDARY WASTEWATER TREATMENT PLANT
-------
equipment includes a sludge rake, scum scraper arm, and scum collection box.
Secondary sludge is pumped to the primary clarifier where it is resettled
with the primary sludge.
The secondary clarifier effluent passes through the existing chlorine contact
chamber of the secondary plant. The chlorine contact chamber has been modi-
fied to include flow measuring and sampling equipment. Chlorine is not added
at any point in the chlorine chamber but instead is added subsequently in the
tertiary plant.
B . Tertiary
Tertiary treatment includes flow equalization, two-stage lime clarification,
dual media filtration and chlorination. Schematics of the tertiary facilities
are shown in Figure '4-2 and in Figures A-l and A-2. The design criteria are
listed in Table A-l, and the hydraulic schematic is shown in Figure B-l. The
influent wet well, which has a capacity of 208 m3 (55,000 gallons) receives
secondary effluent, overflows from the lime clarifiers, flow from the three
tertiary plant sample sinks, and the flow from the north side floor drains.
The wet well provides some equalization of flow. Two variable-speed centrif-
ugal pumps controlled by a manually operated pump controller, lift the waste-
water from the influent wet well to the mix zone of the first lime clarifier.
Each pump has a maximum capacity of 4.2 m3/min (1100 gpm) at a TDH of 20 m
(65 ft).
The first -stage lime clarifier is 17 m (55 ft) in diameter with a sidewater
depth of 6 m (19 ft 6 in) (Figure A- 3) . At a flow of 5678 m3/day (1.5 mgd)
the detention time is 5.3 hours and the overflow rate is 26 m/day (631 gpd/
sq ft) . The volumes of the mix zone, flocculation zone and clarification
zone are 28 m3 (7,330 gal), 92 m3 (24,300 gal) and 1,135 m3 (300,000 gal),
respectively.
Secondary effluent, slaked lime, and polymer are pumped to the mix zone of the
clarifier. Powdered carbon can also be fed at this point. A variable speed
turbine creates an upward flow through the mix zone draft tube and draws solids
into the mix zone for coagulation. A sludge scraper, two inches above the
clarifier floor, rotates slowly and moves sludge gradually to the center sump.
Effluent from the first-stage lime clarifier flows by gravity to the second-
stage lime clarifier (Figure A-4) . Carbon dioxide dissolved in water is fed
to the mix zone of the second stage to precipitate CaC03 and reduce the pH to
about 9.6. Ferric chloride, slaked lime, polymer, and powdered carbon can
also be added to the mix zone of the second -stage clarifier.
The design flow through the second-stage lime clarifier is 5678 m3/day
(1.5 mgd) plus a 757 m3/day (0.2 mgd) feed stream of recycled tertiary efflu-
ent containing dissolved carbon dioxide for pH control. The surface area is
identical to that of the first-stage lime clarifier, however, the overflow
rate is 29 m/day (715 gpd/sq ft). The second stage has a sidewater depth of
5 m (16 ft 6 in) and a detention time of 4.5 hours. The mix zone volume,
12
-------
Trickling Tertiary Influent
Filter Plant Pump Station
Filter
Backwash
H2S04
•FeCLa Dual-Media Filters
Primary/Secondary J
Sludge j
—ITank Truc_k
[Loading Area
SHAGAWA
LAKE
Filter Backwash
ualization Tank
Wet Well #3 HI h
_._.._}_,
^ Supernatant
i'eTt'WasTT' I
Lift Sta. #2
Sludge Holding j
Tank i
LEGEND
Process Flow
-Sludge Flow
, Process
Return Flow
'STINKY DITCH"
Sludge
Holding Pond
FIGURE 4-2. FLOW DIAGRAM OF ELY TERTIARY WASTEWATER TREATMENT PLANT
-------
flocculation zone volume, and clarification zone volume are 23 m3 (6,130
gallons), 77 m3 (20,400 gallons) and 954 m3 (252,000 gallons), respectively.
Each lime clarifier has a maximum hydraulic capacity of 11,356 m3/day
(3,0 mgd). The two lime clarifiers each have overflow drains and each clari-
fier can be emptied by gravity to one foot above the floor level.
Affixed to each lime clarifier is a sample sink equipped with a pH meter and
sample ports. Sample lines lead from the upper mix zone, lower mix zone,
upper flocculation and lower flocculation zones, and effluent weir to the
sample sink. A port for a variable depth sampler is also located at the
sample sink. The pH, solids volume, and sludge blanket depth can be monitored
at the sampling sinks.
The second-stage lime clarifier effluent flows by gravity to a splitter box
which splits the wastewater into four equal streams and directs the wastewater
to the gravity filters. Chlorine, sulfuric acid, and ferric chloride can be
added to the second-stage effluent ahead of the splitter box. Each of the
four gravity filters (Figure A-5) is 3.7 m (12 ft) in diameter, 4.9 m (16 ft)
high, and has a surface area of 10.5 m2 (113 Sq ft). The design hydraulic
loading is 5.6 m/hr (2.3 gpm/ft2) at 5678 m3/day (1,5 mgd) and the design max-
imum hydraulic loading to the filters is 8.6 m/hr (3.5 gpm/ft2). The filter
media consists of a 0.6 m (2 ft) layer of anthracite above a 0.3m (l ft) layer
of sand. The anthracite has an effective size of 0.8 to 0.13 mm with a uni-
formity coefficient of 1.7. The effective size of sand is 0.4 to 0.5 mm with
a uniformity coefficient of 1.4 minimum to 1.65 maximum.
The gravity filters can be backwashed automatically on the basis of either
elapsed time or head loss, or backwashing can be initiated manually. Normally
the filters are backwashed automatically every 24 hours. While one filter is
being backwashed, the other three filters remain in service, The backwash
water is held in a 26 m3 (6,930 gallon) chamber on the top of each filter
(Figure A-5). The backwash cycle includes 5 minutes of air scour at 1.5 m/min
(4.9 scfm/ft2) and a backwash rate of 0.61 m/min (15 gpm/ft:-) until the cham-
ber is empty.
The effluent from the gravity filters flows to the effluent water pump station
(Figure 4-2) and is either discharged to Shagawa Lake or is recycled through
the tertiary plant. From 15 to 25 percent of the filtered wastewater is re-
cycled through the tertiary plant as process water. The tertiary plant can
use both city water or recycled effluent for the plant processes. Normally,
recycled effluent is used for all process purposes except to mix polymer.
Process water is used for:
dissolution of CO- and Cl2
slaking CaO and as lime ejector water
bearing water to the fiber bearings of the two lime clarifiers
and the sludge thickener
14
-------
0 tertiary influent pump seal water
0 sludge pump flushing water
0 powdered carbon wetting and transport
0 vacuum filter belt wash water
0 tertiary plant cleanup
The treated wastewater not recycled passes through the parshall flume to
Shagawa Lake. The parshall flume is both a flow metering station and a sam-
pling station. The parshall flume meters and samples automatically the ter-
tiary plant effluent and any tertiary plant bypass.
The tertiary plant is designed so that the treatment units can be combined
into various treatment systems. The two-stage lime clarifiers are operated
in series with the second-stage clarifier effluent being split among the four
parallel gravity filters. The clarifiers are piped so that they may be oper-
ated in parallel. The lime clarifiers, gravity filters, and the effluent res-
ervoir can each be bypassed for maintenance and repair.
Sludges from the first and second-stage lime clarifiers and sludge from the
trickling filter plant are normally pumped to an 8 m (26 ft) diameter x 5 m
(16 ft 6 in) high picket-type gravity thickener. The sludge can also be routed
to a 757 m3 (200,000 gallon) emergency holding pond, to a tank truck loading
station, or to the vacuum filter.
Thickener underflow is pumped by a variable speed progressive cavity pump to a
1.8 m (6 ft) diameter, 2.5 m (8 ft) face belt type vacuum filter. Filter cake
is discharged via conveyor to hoppers where it can be loaded by gravity into a
dump truck for ultimate disposal in a sanitary landfill. Thickener underflow,
in an emergency, can be discharged to the 757 m3 (200,000 gallon) sludge hold-
ing pond. The thickener supernatant is pumped via lift station #1 to the head
of the secondary plant.
C. Appurtenant Equipment
The chemical feed systems include lime, ferric chloride, sulfuric acid, carbon
dioxide, chlorine, polymer, and powdered carbon. Pebble lime (CaO) is stored
in two 18 ton (metric), (20 ton) storage bins. The bins discharge directly to
duplicate paste slakers. The slaked lime is transported to the first-stage
lime clarifiers by a system of hydraulic ejectors. The lime feeder belt speed
is proportioned to the influent flow and the lime dose is set manually by means
of a timer mechanism which turns the feeder on and off. The maximum capacity
of each lime feeder is 454 kg/hr (1,000 Ibs/hr), Lime usage is determined
from reading the lime slaker totalizer daily.
Ferric chloride is stored in a 23 m (6,000 gallon) tank which supplies two
0.11 m (30 gallon) day tanks. Two flow-proportional diaphragm pumps feed
15
-------
to the second-stage lime clarifier and to the influent pipe to the
splitter box. The iron dose is set by pump stroke frequency, which is propor-
tional to the influent flow, and by manually adjusting the stroke length, A
daily average Fed3 dose is calculated by measuring the drop in the day tank
level.
Sulfuric acid is stored outside of the building housing the tertiary plant in
a 15 m3 (4,000 gallon) tank. The acid is pumped by a flow-proportional dia-
phragm pump to a point in the pipeline ahead of the splitter box.
Chlorine is purchased in 68 kg (150 Ib) cylinders. Two cylinders are used
simultaneously. A flow proportional chlorine feeder, using recycled plant
effluent, feeds chlorine to the splitter box influent pipe and to the effluent
from the gravity filters. Average daily chlorine dose is determined from
change in weight of the chlorine cylinders.
Liquid carbon dioxide, used for pH control, is stored in a 22 metric ton
(24 ton) refrigeration unit and is vaporized and dissolved in approximately
750 m3/day (0.2 mgd) of recycled plant effluent. The C02 dosage in pounds/day
is read from the gas feeder 24 times per day, and the calculated dosage is the
average of the 24 readings.
Powdered activated carbon is purchased in 20 kg (45 Ib) bags which are stored
in a room with only non-spark switches and equipment. The powdered carbon
feed system includes a hopper, a volumetric feeder, ejector system and piping
to the mix zones of both clarifiers. The powdered carbon feeder is not flow
proportional.
Dry polymer is dissolved in city water and pumped to the first-stage lime
clarifier by a pump that is not flow proportional. Initially, a commercial
polymer mixer was used but it often plugged and failed to operate. Polymer is
now added by hand and mixed with city water in a day tank. There have been no
maintenance problems using manual polymer makeup during a one year operating
period. Polymer dosage is calculated from the daily inch drop in the day tank
and the calculated concentration of polymer per inch of tank depth.
In case of power failure, a diesel-powered emergency generator ensures con-
tinued operation of the tertiary plant. Equipment connected to the emergency
generator include:
Lights in emergency generator room
One influent sewage pump
One lime slaker
Boiler, heating units
0 Air exchangers
Two effluent pumps
16
-------
0 Turbine and sludge rake for both lime clarifiers
0 Exhaust fan above gravity filter pit
One underflow pump
0 Thickener drive
0 Carbon dioxide refrigerator and compressor
0 All sump pumps
0 Service water pumps
The tertiary plant is totally housed in a 2004 m2 (21,570 sq ft) building.
Included in the building are a 130 m^ (1400 sq ft) office and analytical lab-
oratory area, work bench, showers, rest rooms, operator control room; opera-
tional panel with an annunciator tied into the equipment, three large ventila-
ting units, a boiler, emergency generator, and auxiliary equipment. Two addi-
tional storage areas were constructed because of the great need for a place to
store spare parts, laboratory chemicals, emergency heaters, etc.
D. Analytical Program and Sample Scheduling
Flow proportional wastewater samples are composited at two locations in the
secondary plant and six locations in the tertiary plant. Sample locations are
between the comminutor and primary clarifier ("Raw Sewage"), the chlorine con-
tact chamber ("Secondary Effluent"), the pipe ahead of the magnetic flow meter
for the first-stage lime clarifier, the effluent weir of the first-stage clar-
ifier ("Influent second-stage lime clarifier"), the effluent weir of the
second-stage clarifier, the splitter box for gravity filter influent, the
viewing well ("Gravity filter effluent"), and the effluent metering station
("Effluent-discharge to Shagawa Lake").
Sludge samples are taken of the combined primary-secondary sludge from the
primary clarifier underflow ("Primary-secondary sludge"), from the first-stage
lime clarifier underflow, second-stage lime clarifier underflow, and the vac-
uum filter sludge cake. A sample of the sludge thickener supernatant, which
is recycled to the head of the secondary plant, is also taken. The plant
operators obtain and composite flow-proportional samples from each location
as described. The samples are picked up each midnight and delivered to the
laboratory the next day. The analytical sampling and analysis schedule, shown
in Table 4-1, indicates the sampling frequency, compositing method, and
frequency of analytical testing.
17
-------
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SECTION V
PROCESS PERFORMANCE
A. Secondary Plant
The influent flow to the trickling filter plant includes wastewater from the
City of Ely and discharges through three package lift stations adjacent to the
plant site as shown in Figure A-l. Tertiary plant return streams flow to the
208 m3 (55,000 gallon) equalization sump of lift station #1 and are pumped to
the plant influent. Lift station #2 pumps water from a creek, "Stinky Ditch",
which contains some septic tank drainage, and also pumps the runoff from the
sludge holding pond. Lift station #3 picks up the swamp water situated east
of the trickling filter plant and discharges it to the plant influent sewage
pipe.
Influent to the trickling filter plant averages 4,163 m^/day (1.1 mgd). For
eight months of data as shown in Table C-l, Appendix C, total phosphorus aver-
aged 7.07 mg/1, SS averaged 202 mg/1, alkalinity averaged 181 mg/1 as CaCO-,
BOD averaged 90 mg/1 and the median pH was 7.9.
Eight months of trickling filter plant performance data, as shown in Tables
C-2 and C-3, Appendix C, were obtained during the first year of the project.
The trickling filter plant removed an average of 46 percent of the total phos-
phorus, 78 percent of the suspended solids, 21 percent of the alkalinity and
57 percent of the BOD. The concentrations in the trickling filter plant efflu-
ent averaged 3.81 mg/1 total P, 44 mg/1 SS, 139 mg/1 alkalinity, and 39 mg/1
BOD. The effluent median pH was 7.3.
B. Tertiary Plant
1. Two-Stage Lime Clarification
Phosphorus Removal
During normal operation the pH in the first-stage lime clarifier was raised to
11.8 or higher by the addition of slaked lime to precipitate hydroxyapatite
and magnesium hydroxide. The operating pH, lime dose required, incoming alka-
linity, and first-stage effluent total phosphorus concentration for the first
year of operation are shown in Figure 5-1. As can be seen in the figure, ther
pH varied between 11.84 and 12.03 and the lime dose varied between 266 and
344 mg/1. For this period of operation, total phosphorus in the first-stage
clarifier effluent averaged 0.298 mg/1.
19
-------
u. os
,
o
-
.6
.5
.4
.3
.2
FIGURE 5-1. MONTHLY AVERAGE VALUES OF INFLUENT ALKALINITY,
LIME DOSE, CLARIFIER pH, AND EFFLUENT TOTAL P FOR
FIRST STAGE LIME CLARIFIER.
20
-------
The second-stage lime clarifier was operated at a pH of 9.6 and was originally
designed so that C02 following dissolution could be added to the influent of
the second-stage clarifier. Shortly after start-up, the influent pipe plugged
with CaC03 and had to be taken apart and cleaned. To avoid this frequent
occurence, the situation was corrected by adding dissolved CCU directly to the
second-stage mix zone instead of to the influent pipe. Also during start-up
it was determined that the effluent from the second-stage clarifier was very
unstable and CaCOg was being precipitated on the filter media. Although de-
posited CaCOj removed soluble phosphorus to very low levels, high head losses
and short filter runs resulted. This problem was resolved after the sulfuric
acid feed system was placed in operation to reduce the second-stage effluent
pH from a range of 7.6 to 9.5 to a range of 7.5 to 7.8 thereby producing a
negative Langelier index. While this resulted in dissolution of the carbonate
deposit and prevented further precipitation, soluble phosphorus was no longer
removed by the filters.
Effect of Solids Volume on Phosphorus Removal
During the initial stages of plant operation, it was observed that the volume
of solids in the mix zone and the ratio of upper mix zone solids volume to
lower mix zone solids volume were critical in the control of the performance
of the two lime clarifiers. The solids brought into the mix zone provided
surfaces which theoretically promote the completion of chemical reactions and
improve flocculation.
Therefore, a procedure was initiated through which the solids volume in the
mix zone of the lime clarifiers was controlled by sampling and testing the
upper and lower mix zones on an hourly basis. The test involved filling a
one liter graduate and allowing 30 minutes for the sample to settle. After
30 minutes the solids level in the graduate was read and recorded in milli-
liters per liter. Through this procedure, it was determined that a satisfac-
tory upper mix zone solids volume in the first-stage lime clarifier ranged
from 140 ml/liter to 280 ml/liter. As seen in Figure 5-2, the total phos-
phorus removal was 91 percent or greater when the upper mix zone solids volume
averaged 140 ml/liter or more. When the upper mix zone solids volume de-
creased to 84 ml/liter, total phosphorus removal by the first-stage clarifier
dropped to 84 percent.
In the second-stage lime clarifier sufficient solids in the upper mix zone
also resulted in satisfactory total phosphorus reduction. As shown in Figure
5-3, when the upper mix zone solids volumes averaged less than 70 ml/liter,
total phosphorus removal ranged from 51 to 67 percent. When the upper mix
zone solids volume was greater than 140 ml/liter, total phosphorus removal
ranged from 72 percent to 84 percent, and total phosphorus concentration in
the clarifier effluent averaged 0.04 to 0.06 mg/1.
A second operational parameter used for clarifier operation was the ratio of
upper mix zone solids volume to the lower mix zone solids volume. As an oper-
ational tool it indicated whether the turbine speed was great enough to pump
21
-------
100_
95
LU
ee.
90
NJ
N)
co
O
85
O 80
I
I
I
I
I
250
0 50 100 150 200
UPPER MIX ZONE SOLIDS VOLUME, ml/liter
FIGURE 5-2. INFLUENCE OF UPPER MIX ZONE SOLIDS VOLUME ON
TOTAL PHOSPHORUS REMOVAL IN FIRST STAGE LIME
CLARIFIER.
_J
300
-------
<
o
200 i—
FIGURE 5-3. MONTHLY AVERAGE VALUES OF UPPER MIX ZONE
SOLIDS VOLUME, PERCENT TOTAL PHOSPHORUS
REMOVAL, AND TOTAL PHOSPHORUS CONCENTRATION
IN SECOND STAGE LIME CLARIFIER EFFLUENT.
23
-------
sufficient solids into the mix zone. Although the equipment supplier recom-
mended a ratio of 0.95 for both clarifiers, operating experience proved other-
wise. First-stage total phosphorus removal was satisfactory with a ratio
above 0.72, and very good removal was attained at a ratio between 0.85 and
0.90. In the second-stage clarifier, the most effective ratio was normally
between 0.75 and 0.90.
Because of the very good mixing in the second stage, the turbine speed was
rarely adjusted in this unit. Occasionally the turbine would not pump suffi-
cient solids to the upper mix zone of the second-stage presumably because the
intake to the turbine was blocked by heavy solids. This situation was cor-
rected by temporarily increasing the speed of the sludge rake and by increas-
ing sludge withdrawal.
Control of the Solids Blanket
The sludge blanket depth in the lime clarifiers refers to the depth of solids
which exist beneath the solids-liquid interface. It was necessary to con-
trol the blanket level so that it was high enough to provide solids for the
mix zone, yet low enough to prevent solids carryover to the effluent weir.
While the blanket depth was influenced by operating conditions, it was con-
trolled principally by the sludge blowdown rate. The blowdown rate was regu-
lated by the balance between sludge pumping rate and pumping interval. Ordi-
narily the pump speed was held constant while the blowdown rate was adjusted
by increasing or decreasing the duration of the on/off pumping cycle.
In the first-stage lime clarifier the characteristics of the solids blanket
depended on lime dosage, polymer addition, and flow, in addition to the sludge
blowdown rate. Lime dosage was adjusted according to pH requirements however,
a large increase in lime dosage increased solids and thus added to the blanket
depth. As a general rule, lime dosages were not increased specifically to
build the solids blanket. (Flow and polymer addition are discussed later.)
The average depth of the first-stage solids blanket was 1.8 m (6 ft), ranging
from 1.4 m (4.5 ft) to 2.7 m (9 ft).
In the second-stage clarifier, the solids blanket, a combination of heavy cal-
cium carbonate and iron precipitate, varied from less than 0.6 m (2 ft) to
1.8m (6 ft) in depth. Experience demonstrated that a blanket depth of 1.2 m
(4 ft) provided optimum percent removal of total phosphorus by the unit. The
solids blanket was held at this level during the months of September, October,
and December, 1973 and January and February, 1974 when the percent removal of
phosphorus was relatively high.
Although the clarification process could be operated either with or without a
sludge blanket, the existence of a blanket in the second stage aided solids
capture. However, it was observed that after the solids blanket had aged for
several weeks, solids capture became optimum. For example, the second-stage
clarifier was refilled October 31, 1973. By November 7, soluble phosphorus in
the second-stage effluent was 0.029 mg/1 and the particulate: phosphorus was
0.045 mg/1. During the following two weeks, the sludge blanket depth stabil-
ized at 1.2 m (4 ft) and particulate phosphorus decreased to a low of 0.017
mg/1. Only a slight increase in soluble phosphorus removal was noted. On
24
-------
another occasion when the second-stage clarifier was again refilled, support-
ing data were obtained further demonstrating that solids capture in the clari-
fier improved as the solids blanket aged.
Chemical Addition (Cationic Polymer in First Stage)
Polymer addition to the first-stage lime clarifier began in April 1973. Ini-
tially, a cationic polymer, Betz 1150, was used at a dosage level of 0.53 mg/1.
In early May, Betz 1200 was substituted for Betz 1150. Betz 1200 was more
viscous and difficult to dissolve so on May 10 polymer addition was discontin-
ued. On May 23 an attempt was made to feed Betz 1130 but it too was difficult
to dissolve and to pump. On June 1, addition of Betz 1150 to the first-stage
clarifier began again at a dosage level of 0.20 mg/1. This dose appeared
effective in controlling the solids blanket.
The addition of Betz 1150 improved process performance through better mangage-
ment of the solids inventory, and by permitting a lower blowdown rate to main-
tain the proper sludge blanket depth. When polymer addition was stopped, the
first-stage solids blanket rose rapidly. When polymer was again added, the
blanket depth decreased and stabilized near 1.8 m (6.0 ft). Other than pre-
venting solids carryover, polymer addition seemed to have no influence on
first-stage clarifier effluent quality.
Chemical Addition (Iron in Second-Stage Clarifier)
Beginning in March 1973, ferric chloride was added to the mix zone of the
second-stage lime clarifier. The dosage was 6.0 mg/1 as Fe+3.
Theoretically, some hydrolysis products of Fe+^ ion causes coagulation of
phosphorus (2). Although FeP04 is considered to be mostly soluble in neutral
and alkaline wastewater, some hydrolyzed Fe"1"^ compound presumably coagulated
the phosphorus at the second stage pH of 9.6 and thus aided in total phos-
phorus removal (3).
For a two-week period in June and July, the FeClj dosage to the second lime
clarifier was reduced significantly. The total phosphorus removal by the
second-stage clarifier as a function of ferric chloride dosage is shown in
Figure 5-4. From June 28 to July 7, when the FeClg dosage was reduced from
5.2 mg/1 to 2.2 mg/1, the total phosphorus removal deteriorated from an aver-
age of 65 percent to less than 50 percent. In addition, the solids volume in
the upper mix zone decreased along with the decrease in the iron dose.
Whether the decrease in the iron dose or the decrease in the solids volume ,
caused the reduction in total phosphorus removal is not clear.
It was concluded that a minimum iron dosage, somewhere between 3.0 and 6.0
mg/1 as Fe"1"^, was needed to ensure adequate phosphorus removal and to improve
clarification.
25
-------
80
^o
Jf70
O
ui
at
60
of.
O
50
40
30
1
V
_L
I
I
I
I
01234567
IRON DOSE, mg/l as Fe+3
FIGURE 5-4. INFLUENCE OF IRON DOSE ON TOTAL
PHOSPHORUS REMOVAL IN SECOND
STAGE LIME CLARIFIER.
26
-------
Effect of Flow on Performance of Lime Clarifiers
The tertiary plant influent flow averaged 4315 m3/day (1.14 mgd) for 12 months
and on a monthly average basis varied from 3104 m^/day (Q.,82 mgd) to 5678
m3/day (1,50 mgd). The minimum daily flow was 2877 m^/day (0,76 mgd) and the
maximum daily flow was 8706 m3/day (2.3 mgd). The second-stage lime clarifier
influent flow included the first stage flow plus 757 m3/day (0.2 mgd) of recir-
culated tertiary treated water used for CC>2 dissolution,
There was some indication that large variations in the flow through the first-
stage lime clarifier affected total phosphorus removals in the first-stage
clarifier. High flows caused the solids blanket in the first-stage clarifier
to rise rapidly. For example, when high flows were experienced in July, the
solids blanket rose to over 4.8 m (16 ft) allowing carryover of particulate
phosphorus. The first-stage effluent total phosphorus on July 18 was 0.83 mg/1,
which was about three times the normal monthly average. On the other hand, in
October when heavy rains again occurred, the sludge blowdown rates were in-
creased soon enough to prevent the carryover of phosphorus-laden solids. The
major difference in the operation of the first-stage lime clarifier during
these two instances of high flows was the control of the solids blanket in
order to prevent solids carryover.
Unlike the performance characteristics just described for the first-stage clar-
ifier, large increases in plant flow did not greatly influence the solids blan-
ket level in the second-stage lime clarifier nor did they greatly affect phos-
phorus removal in the second-stage clarifier. This contrast in clarifier per-
formance is shown in Figure 5-5. When the daily flow averaged about 3780 m3
(1.0 mgd) prior to October 8, total phosphorus removal was 95-96 percent in the
first stage and 85 percent in the second stage. When the plant flow increased
between October 8 and October 17, phosphorus removal in the first stage dropped
from 95-96 percent to about 90 percent while phosphorus removal in the second
stage remained fairly stable.
It should be noted that during the periods of high plant flows resulting from
rainstorms, the chemical consumption for coagulation did not increase propor-
tionately because there was a dilution of influent alkalinity.
Phosphorus Removal Summary
Two lime clarifiers operating in series removed 98.2 percent of the tertiary
plant influent total phosphorus during a 12-month period. The first stage
total phosphorus removal ranged from 84 percent to 95.5 percent. During the
same period of time, the second-stage lime clarifier reduced total phosphorus
in the effluent of the first lime clarifier by an average of 72.2 percent,
ranging from a low of 49 percent to a high of 84 percent. Variation in plant
operation, including draining of the second-stage clarifier, accounted for
occasions of poor phosphorus removals. Total phosphorus concentration in the
first-stage effluent varied from a low monthly average of 0.20 mg/1 to a high
of 0.57 mg/1 (Appendix D). The second-stage lime clarifier effluent total
phosphorus varied from a low of 0.034 mg/1 to a high of 0.171 mg/1.
27
-------
m.o 100
o^
<_J-
£< 90
i°
o[f 80
MONTHLY AVERAGE OF DATA
t-._,_»_.S __...'
70 U—L
* i i
i i i i
O 94
LU
O
^ 90
88
i i i i i i i i i i i i
•o
t 2.2
^ 2.0
O 1.8
^ 1.6
^ 1.4
2 1-2
^ 1.0
> 0.8
iii
1
10 15 20
OCTOBER, 1973
25
30
FIGURE 5-5. INFLUENCE OF TERTIARY PLANT FLOW ON TOTAL
PHOSPHORUS REMOVAL BY FIRST STAGE AND
SECOND STAGE CLARIFIERS.
28
-------
Suspended Solids Removal
The monthly average suspended solids concentrations in the tertiary plant in-
fluent, the first-stage lime clarifier effluent, and the second-stage clarifier
effluent are shown in Figure 5-6. The variability observed in the influent
solids is due to the fact that the tertiary plant influent flow included the
trickling filter plant effluent together with flow from the tertiary plant
sample sinks and floor drains. The mean monthly tertiary plant influent sus-
pended solids concentrations were as low as 36 mg/1 and as high as 122 mg/1
with a 12-month average of 70 mg/1.
Influent suspended solids increased significantly on four occasions when the
second-stage lime clarifier was drained. Draining a lime clarifier returned
the contents of the clarifier to the tertiary influent wet well. The points
shown separately in Figure 5-6 for the months of October, February and March
represent the increment added to the monthly average values by the clarifier
solids.
Although the suspended solids to the first stage varied considerably, the con-
centrations in both the first-stage and second-stage effluents were stable, as
shown in Figure 5-6. The first-stage effluent SS monthly average varied from
7 mg/1 to 16 mg/1 with a 12-month SS average of 9.6 mg/1; and the second stage
solids varied from 3.5 mg/1 to 12 mg/1 with a 12-month average of 7.1 mg/1.
Optimum clarification in the second stage was desirable from the standpoint of
both solids and phosphorus removal. Efficient solids removal was needed to
prevent high solids loading to the gravity filters which would have resulted
in shorter filter runs. Also, if particulate phosphorus was not settled out,
it would have been resolubilized between the clarifier and filter when the
second-stage effluent pH was adjusted from 9.6 to less than 8.0. This resolu-
bilized phosphorus would have escaped filtration and been discharged in the
final effluent to Shagawa Lake. During the year of operation, even in the
month of poorest clarification by the lime clarifiers, the suspended solids
concentration was 40 percent of the discharge standard (30 mg/1). This shows
that the standard could have been met without the use of a filter.
Turbidity Removals
The influent turbidities to the first-stage lime clarifier were variable
throughout the year. Minimum and maximum average monthly influent turbidities
were 10 JTU and 41 JTU, respectively. The 12-month average was 23 JTU. The
first-stage effluent turbidities were nearly constant after the initial months
of operation in April and May. The average turbidity for those two months was
6.0 JTU, and the average turbidity during the remaining 10 months was 2.0 JTU,
varying from 1.3to 2.7 JTU. Maintaining good control of the solids inventory
in the first-stage clarifier was the principal factor in lowering the turbidity
levels in the first-stage effluent.
29
-------
o>
E
O
CO
O
LU
Q
o.
«/>
3
to
120
110
100
20
• FIRST STAGE INFLUENT O
A FIRST STAGE CLARIFIER EFFLUENT
• SECOND STAGE CLARIFIER EFFLUENT
O Indicates the influence on the monthly average
SS values due to recirculation of the contents of
the second stage clarifier to the influent.
FIGURE 5-6. MONTHLY AVERAGE SUSPENDED SOLIDS IN FIRST
STAGE INFLUENT, FIRST STAGE EFFLUENT AND SECOND
STAGE EFFLUENT.
30
-------
As previously discussed, cationic polymer was useful in stabilizing the solids
blanket, which also resulted in lower first-stage effluent turbidities. Even
with flows as high as 50 percent above design flow, turbidity levels in the
first-stage effluent were consistently low except when the solids blanket was
allowed to overflow the weir.
The second-stage effluent turbidity is shown in Figure 5-7 together with the
total phosphorus and particulate phosphorus concentrations in the second-stage
effluent. The second-stage effluent turbidity for 12 months averaged 2.0 JTU
with monthly averages ranging from 0.85 JTU to 3.4 JTU. The U.S. Public
Health Service limits turbidity in public water supplies to 5.0 units (4).
Particulate phosphorus, which is the difference between the unfiltered and
filtered phosphorus, was found to be directly related to effluent turbidity.
This would suggest that the particulate phosphorus could conceivably be moni-
tored by using a turbidimeter with a continuous readout. Turbidity measure-
ments have been considered more relevant to water treatment than wastewater
treatment (5). To achieve the desired effluent total phosphorus concentration,
it was necessary to achieve a degree of clarification similar to that attained
in the treatment of potable water. Turbidity measurement, therefore, became
a valuable tool in process control. Turbidity analyses were also quicker and
easier to perform than suspended solids tests. The first year's data indicate
that turbidity measurements could be used for process control with less reli-
ance on the more time consuming suspended solids analysis.
Organic Removal
Routine analysis for total organic carbon did not begin until December 1973.
Thereafter, samples of first-stage lime clarifier influent, first-stage efflu-
ent, second-stage effluent, and tertiary plant effluent were analyzed twice
per week for TOC. Table 5-1 shows the TOC removals through the two-stage clar-
ification system. The first-stage influent averaged 46.0 mg/1 for four months.
First-stage effluent and second-stage effluent TOC averaged 23 mg/1 and 18.5
mg/1, respectively. The first-stage lime clarifier removed an average of 49
percent of the influent TOC, while the second-stage lime clarifier removed
only 9 percent of the tertiary plant influent TOC. Together, the two lime
clarifiers removed 60 percent of the tertiary plant influent TOC. Whether TOC
removal, based upon data obtained in the winter months, could be extrapolated
for the whole year is not clear. From December through March the flow was
relatively low and steady, unlike the rest of the year.
The TOC analysis schedule which was set up in December 1973 was expected to
continue through 1974. During this time the effect of powdered carbon addi-
tion to the mix zone of the second lime clarifier was to be examined.
Chemical Addition Prior to Gravity Filters
The effluent from the second-stage lime clarifier passed through the splitter
box to the gravity filters. Chemicals were injected into the wastewater in
the pipe between the second-stage clarifier and the splitter box. The chem-
icals included sulfuric acid for pH adjustment, ferric chloride for phos-
phorus removal, and chlorine for disinfection. The pipeline turbulence was
sufficient to ensure good mixing.
31
-------
I—I I I I
I I I I I
4.0
9 2.0
to
OL
D
"- 0
J—I—I—I—I I I I I I I
o>
E
o
z
LLJ
Q.
to
3
to
FIGURE 5-7. MONTHLY AVERAGE CONCENTRATIONS OF SUSPENDED
SOLIDS, TURBIDITY, PARTICULATE PHOSPHORUS AND TOTAL
PHOSPHORUS IN SECOND STAGE CLARIFIER EFFLUENT.
32
-------
TABLE 5-1 TOTAL TOC REMOVAL BY TERTIARY LIME CLARIFICATION *
PROCESS
Influent (mg/1) Effluent (rag/l) % Reduction Thru Process
Range Average Range Average Range Average
First-stage
Clarifier
Second-stage
Clarifier
Two-stage
System
33-63 46 19-30 23 38-66 49
19-30 23 14-25 18.5 9-27 19
33-63 46 14-25 18.5 43-75 60
* Based on data Dec. 1973 - Mar. 1974
-------
Sulfuric acid was added to the second-stage effluent which lowered the pH to
about 7.5 prior to filtration. At this pH, a negative Langelier Index was
achieved which prevented deposition of CaC03 on the filters. Acid addition
also decreased the pH to within the 6.5 to 8.5 range required by the State of
Minnesota, and no further pH adjustment was necessary before the treated
wastewater was discharged to Shagawa Lake.
Subsequent to initiation of pH adjustment of the filter influent, large
amounts of scale were removed from the filters. In April, the gravity filter
influent and effluent Ca+2 concentrations were 57.3 mg/1 and 65.7 mg/1,
respectively. In May the filter influent and effluent Ca+2 averaged 39.3 mg/1
and 49.7 mg/1, respectively (Appendix D). The increase in calcium through the
gravity filters was due to the dissolution of CaC03 scale that had built up on
the filters prior to April, 1973.
A^negative effect of lowering the filter influent pH with acid was the resolu-
bllization of a portion of the remaining particulate phosphorus. The extent
to which resolubilization occurred resulted in an increase of soluble phos-
phorus in the filter influent from an average of 0.023 mg/1 to an average of
0.065 mg/1. Such a concentration was unacceptable since soluble phosphorus is
unaffected by filtration and a final effluent concentration of 0.065 mg/1
exceeded the design goal of 0.050 mg/1 total phosphorus.
In order to counteract the dissolution of particulate phosphorus, an average
of 2.66 mg/1 of ferric chloride (as Fe+3) was added to the filter influent
which served to precipitate a portion of the residual soluble phosphorus.
Although dissolution was still experienced, the increase in soluble phosphorus
was smaller, and the filter influent soluble phosphorus concentration was re-
duced to 0.043 mg/1.
Chlorine for disinfection was dissolved using treated wastewater before being
fed to the filter influent stream. Adding the chlorine prior to the filters
provided contact time for disinfection in the filtered backwash storage com-
partment (Figure A-5). The detention time in the backwash compartment at a
flow of 5678 m-Yday (1.5 mgd) was 27 minutes.
Grab samples for coliform analysis were obtained from the effluent reservoir
during the 10 months of operation between June 1973 and March 1974. The grab
samples were analyzed four times each week for total coliform and once each
week for fecal coliform. In seven of the 10 months the presence of total coli-
form was not reported in any of the 100 milliliter samples. In nine out of the
10 months there were no fecal coliform bacteria reported. Out of approximately
160 grab samples collected and analyzed for total coliforms, only six were
found to have one or more total coliforms per 100 ml.
Without chlorination, coliform reappeared in the tertiary plant effluent. In
October, no chlorine was added for 3 days. During this 3-day period, total
coliforms were found in two of the three grab samples and fecal coliforms were
present in one of two grab samples. The chlorine residual of the treated
34
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wastewater was checked by the orthotolidine method every 2 hours. From April
to October 1973, the combined chlorine residual averaged 0,50 mg/1. When the
problem of a chlorine shortage evolved in the autumn of 1973, a lower dose,
resulting in a residual of 0.10 mg/1, was tried. However, because a zero re-
sidual was observed on several occasions, dosage at a slightly higher level
was resumed. Thereafter, the combined chlorine residual from November 1973
through March 1974 averaged 0,18 mg/1.
Chlorine dosages for the year averaged 3.0 mg/1. From June to October the
mean dosage was 3.6 mg/1. In November the chlorine dosage was reduced because
of the potential chlorine shortage. The mean chlorine dosage for November
through March was 2,7 mg/1.
2. Dual-Media Filtration
Phosphorus Removal by Dual-Media Gravity Filters
As seen in Table 5-2, an average of 85 percent of the influent particulate
phosphorus, which comprised 68 percent of the total influent phosphorus, was
removed by dual-media filtration. The effluent particulate phosphorus concen-
tration averaged 0.008 mg/1, or 17 percent of the total phosphorus in the
effluent.
As shown in Table 5-2, soluble phosphorus passed through the gravity filters,
with the following exceptions. In April, a period which in part preceded the
addition of H2S04 to the filter influent for pH adjustment, soluble phosphorus
was removed because of buildup of calcium on the filters. In May, therefore,
during the period when CaC03 was dissolving off the filters, soluble phosphorus
showed an increase. Upon achieving chemical equilibrium, the soluble phos-
phorus in the filter influent and effluent was essentially the same.
The effect of variation in hydraulic loading on total phosphorus removal by the
gravity filters is shown in Figure 5-8. The points on the graph represent data
from 20 days of operation in each of the three indicated months and the curve
is an approximate fit to the averaged data for each of the three operating
periods.
The trend of the data indicates that (a) a lower filter loading resulted in a
greater percentage phosphorus removal while less phosphorus removal was
achieved at high filter loadings, and (b) that during a period of operation in
which wide fluctuations in hydraulic loading were experienced (as in August),
a smaller percent phophorus removal resulted than when the filter loadings were
low and consistent (as in January).
Suspended Solids, Turbidity, Iron, and TOG Removal
The performance of the gravity filters with respect to suspended solids, tur-
bidity, iron, and total organic carbon is shown in Table 5-3. The suspended
solids concentration in the filter influent ranged from 5 to 15 mg/1, averaging
9 mg/1 for the year, and effluent suspended solids averaged less than 1.3 mg/1.
Average suspended solids removal was greater than 85 percent. It will be
recalled that the filters also removed 85 percent of particulate phosphorus.
35
-------
TABLE 5-2 PARTICULATE AND SOLUBLE PHOSPHORUS REMOVAL BY DUAL-MEDIA
FILTRATION
PARTICULATE PHOSPHORUS *
SOLUBLE PHOSPHORUS
Month
April, 1973
May
June
July
August
September
October
November
December
January, 1974
February
March
Influent
(mg/1)
0,097
0.093
0,055
0.069
0.034
0.027
0.027
0.027
0.028
0.040
0.045
0.079
Effluent
(rog/1)
0,012
0.014
0.013
0.014
0.003
0.006
0.006
0.003
0.004
0.004
0.007
0.012
Percent
Removal
88
85
76
80
91
78
78
89
86
90
84
85
Influent
'(mg/1)
0.074
0,022
0,043
0.073
0.039
0.016
0.019
0.027
0.017
0.021
0.036
0.065
EfJ-luent
(mg/1)
0,058
0,046
0.033
0.062
0.038
0.016
0.017
0.029
0.017
0.022
0.036
0.065
Percent
Removal
22
<-•>-
23
15
3
0
11
--
0
--
0
0
Average
0.052
0.008
85
0.038
0.037
* Particulate phosphorus = (total phosphorus) - (soluble phosphorus)
"* Soluble phosphorus refers to that portion of the total phosphorus which
passes through a 0.45y membrane filter.
36
-------
fe?
<
>
o
LU
tt
70f-
60
50
40
O
X
Q.
(/)
O
X
Q.
_, 30
20
10
A A A A
0
0
A Aug. '73 Data A Average Aug. Data
D Sept. '73 Data • Average Sept. Data
O Jan. '74 Data * Average Jan. Data
AT | | |
)" 1.4 U> L8
I
I
I
I
I
I
I
I
I
.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
AVERAGE DAILY HYDRAULIC LOADING, gpm/ft2
FIGURE 5-8. EFFECT OF HYDRAULIC LOADING ON TOTAL PHOSPHORUS
REMOVAL BY DUAL-MEDIA FILTRATION.
37
-------
00
Month
Average
Suspended Solids
(mg/1)
Influent Effluent
TABLE 5-3 GRAVITY FILTER PERFORMANCE
Turbidity (JTU)
Iron as Fe
(mg/1)
Influent Effluent Influent Effluent
TOG (mg/1)
Influent
April 1973
May
June
July
August
September
October
November
December
January 1974
February
March
5
15
7
8
7
7
6
7
9
9
10
14
<2 3.1
<1 5.9
<0 . 8 2.4
<;i,6 1.53
<1 1.21
<1 1.30
<1.7 1,48
<1 1.45
<1.4 1.83
<1 1.43
<1.5 2.19
<2 2.8
2.6
1.2
0.45
0,17
0.11
0.33
0.44
0.33
0.32
0.14
0.20
0.43
3.15
2.98
3.40
3,47
3,23
4,24
0,20
0.21
0.17
0.176
0,175
0.30
18.8
17,5
16,1
25,5
16.7
15.0
16.2
23.8
8.7
2.22
0.56
3.41
0.21
19.5
17.9
Percent Removal
>85%
75%
94%
8%
-------
The turbidity data indicate a yearly average removal of 75 percent, and a
yearly average effluent turbidity level of 0.56 JTU, However, it should be
recalled that during the first two months of operation the procedures for
chemical addition prior to filtration were being tested and the filtration
system had not yet attained equilibrium. Therefore, during that period tur-
bidity removal averaged only 58 percent with an average effluent turbidity ot
1 9 JTU After stable operation was achieved, turbidity removal increased to
an average of 83 percent and the effluent turbidity averaged a low 0.29 JTU.
These latter values are more representative of typical operation at the Ely
plant.
As shown in Table 5-3, the filters removed an average of 94 percent of the_
analytically determined iron from the filter influent. There is some quali-
tative indication that higher influent iron concentrations produce higher
effluent iron concentrations. In March 1974, for example, the influent iron
concentration was 25 percent greater than the mean, and the effluent iron con-
centration was 43 percent above the mean.
Based upon four months of data, as shown in Table 5-3, the gravity filters
removed negligible amounts of TOG from the wastewater. Average removal was
8 percent and, at best, was 14 percent. It would appear from the data that
TOC remaining at this point in the treatment train would be soluble and there-
fore unaffected by filtration. Potentially, additional TOC could be removed
by powdered carbon adsorption in the second-stage lime clanfier with subse-
quent removal of the powdered carbon carryover by filtration.
Filter Hydraulics
The hydraulic loading on the gravity filters varied considerably during the
one-year period of operation due to long-term seasonal variations in the waste-
water flow and also to short-term flow increases resulting from stormwater run-
off. The filters were designed for a loading of 5.6 m/hr (2.3 gpm/sq ft) at a
flow of 237 m3/hr (1.5 mgd) with a design maximum peak loading of 8.6 m/hr
(3 5 gpm/sq ft). In practice, the lowest and highest average daily hydraulic
loadings were 3.4 m/hr (1.4 gpm/sq ft) and 9.3 m/hr (3.8 gpm/sq ft), respec-
tively. The monthly mean hydraulic loadings ranged from 3.7 m/hr (1.5 gpm/sq
ft) to 6.4 m/hr (2.6 gpm/sq ft).
The permissible head loss across the filter was about 3.0 m (10 ft). The fil-
ters were backwashed automatically every 24 hours and only rarely was it nece-
sary to backwash more often. In the low-flow months the pressure loss buildup
seldom exceeded.2.1 m (7 ft) during a 24-hour filter run. In December, Janu-
ary and February, the typical head loss for a 24-hour filter run was 1.9 m
(6.2 ft), 1.6 m (5.2 ft) and 1.6 m (5.2 ft), respectively, which was well below
the 3.0 m (10 ft) allowable head loss. In the months of April to November, the
24-hour filter head loss generally varied from 2.4 m (8 ft) to 3.0 m (10 ft).
On one occasion, when the hydraulic loading reached a maximum of 9.3 m/hr
(3.8 gpm/sq ft) the 24-hour head loss buildup was above 3.0 m (10 ft).
39
-------
C. Summary of Tertiary Plant Performance: Plant Reliability and Effluent
Variability ~~ ~ ~ - — -- — -
The 12-month mean total phosphorus removed by the tertiary treatment plant was
99 percent For the year the influent total phosphorus to the tertiary plant
averaged 4.56 mg/1 and the effluent averaged 0.045 mg/1 of total phosphorus.
no ^.averaSe raonthly total Phosphorus concentrations at 7 sampling
points including raw sewage, secondary effluent, tertiary plant samples and
he daily"'!! mo thl^* ^ "" ^^^ in Appendix E Also tabulate
the daily and monthly percent removals of total phosphorus by various waste-
thro^hnMa T^f5- °fly t0tal Ph°SPhorus concentrations^ April I, 1973
first sta^e V !are/ "^ *" FigUI>e ^ The three curves represent the
totaf'nJ *V ^ influent total phosphorus, the first-stage effluent
total phosphorus, and the second-stage effluent total phosphorus
A summary of daily total phosphorus concentrations in the effluent from the
second-stage lime clarifier and the gravity filters is shown in Figure 5-9
The probability curves for total phosphorus are based upon 12 months of daily
average data obtained between April 1, 1973 and March 31, 1974. Each point
shown represents an aggregation of up to 15 daily sample data points.
The tertiary plant effluent quality for 12 months is summarized in Appendix D
and probability curves for turbidity and suspended solids concentrations in
the second-stage clarifier effluent and the filter effluent are shown in
ngures 5-10 and 5-11, respectively. The mean suspended solids concentration
in the tertiary effluent was less than 1.3 mg/1, the mean TOG concentration
was 16 mg/1, the average alkalinity (as CaC03) was 42 mg/1, and the median
effluent pH was 7.5.
The coefficient of variation (% CV) was calculated for the total phosphorus
removal by various treatment plant units. The % CV reflects the percentage
variability and is equal to the monthly standard deviation divided by the
monthly mean. Lower coefficient values indicate more consistent unit process
performance. The percent Coefficient of Variation is shown in Figure 5-12 for
the first and second-stage lime clarifiers, and the gravity filters, as well
as for all three units in series. The general interpretation attached to
40
-------
TABLE 5-4 TOTAL PHOSPHORUS REMOVAL SUMMARY - APRIL 1973 THRU MARCH 1974
First Stage Lime Clarifier Second Stage Lime Clarifier Gravity Filters
Month
April 1973
May
June
July
August
September
October
November
December
January 1974
February
March
Mean
Influent
(me/I)
\. of s
3.62
3,61
4.96
5.22
4.66
3.83
3.65
4.04
4.13
4.44
6.59
5.98
4.56
Effluent
(mg/1)
0.568
0.318
0.267
0 . 306
0.249
0.269
0.217
0.205
0.270
0.347
0.284
0.279
0.298
Percent
Removal
84.3
91.2
94.6
94.1
94.6
93.0
94.0
94.2
93.5
92.2
95.7
95.3
93.5
Effluent
(mg/D
0.171
0,115
0,097
0.137
0.070
0.046
0,034
0.056
0.046
0,060
0.060
0,105
0.083
Cumul . Percent
Removal
95.3
96.8
98.0
97.4
98.5
98.8
99.1
'98.6
98.9
98.6
99.1
98.2
98.2
Effluent
(mg/1)
0.070
0.060
0.046
0.076
0.041
0.022
0.023
0.032
0.021
0.026
0.043
0.077
0.045
Cumul Per-
cent Removal*
98.1
98.3
99.1
98.5
99.1
99.4
99.4
99.2
99.5
99.4
99.3
98.7
99.0
Percent
Remaining
1.9
1.7
0.9
1.5
0.9
0.6
0.6
0.8
0.5
0.6
0.7
1.3
1.0
Cumulative percent removal as a function of first stage clarifier influent total phosphorus
concentration
-------
0.4
0.2
o>
E
Z
O
0.1
.08
u
O
u
s -04
X
a.
«/»
O
I
a.
< .02
O
.01
0.01
I I
1 I T
I I
I
i i n i r
SECOND STAGE •
CLARIFIER EFFLUENT •
•* FILTER EFFLUENT
NOTE: EACH POINT REPRESENTS AN AGGREGATION
OF 10-15 DAILY SAMPLE DATA POINTS.
I
I
0.2
I I I
I
1
I
_L_L
98
99.9 99.99
2 5 10 20 40 50 60 80 90
PROBABILITY %, equal to or less than
FIGURE 5-9. VARIABILITY OF TOTAL PHOSPHORUS IN SECOND STAGE CLARIFIER EFFLUENT AND
FILTER EFFLUENT, APRIL 1, 1973 TO MARCH 31, 1974.
-------
10
8.0
7.0
6.0
5.0
4.0
3.0
2.0
| 1.0
2 -8
.7
.6
.4
i—
rr~i
' ' '
SECOND STAGE EFFLUENT
*•
•
FILTER EFFLUENT
NOTE -- EACH POINT REPRESENTS AN AGGREGATKJN
OF 10-25 DAILY SAMPLE DATA POINTS.
I
I I I I
0.01
0.1
1
99.9 99.99
10 20 30 40 50 60 70 80 90 95 98 99
PROBABILITY %, equal to or less than
FIGURE 5-10. VARIABILITY OF TURBIDITY IN SECOND STAGE CLARIFIER EFFLUENT AND FILTER EFFLUENT
APRIL 1,1973 TO MARCH 31, 1974.
-------
100
80
60
40
20
o>
E
10
Z °
LU
u
O 4
Q
O
a
Ul
Q
Z
UJ
| 1.0
to
.8
.6
.4
.2
.1
C T
T~I i i i i i i j i i—r
CLARIFIER EFFLUENT •
FILTER EFFLUENT
NOTE: EACH POINT REPRESENTS AN
AGGREGATION OF 15-40 DAILY
SAMPLE DATA POINTS.
0.01 0.1
1 I L
J L
_L
J L
1
-L
2 5 10 20 30 50 70 80 90 99 99.9 99.99
PROBABILITY %, equal to or less than
FIGURE 5-11. VARIABILITY OF SUSPENDED SOLIDS IN SECOND STAGE CLARIFIER
EFFLUENT AND FILTER EFFLUENT, APRIL 1, 1973 TO MARCH 31, 1974.
44
-------
COEFFICIENT OF VARIATION (% C.V.) = "^^iT Xl°°
50
SECOND STAGE CLARIFIES
10
5
04
co a
£<
o
<•
«
TERTIARY TREATMENT PLANT
* *
c
3
_x
3
a
0)
U
0
o
Z
«•» n- c -Q
* K! o v
Q £ -> "•
FIGURE 5.-12. MONTHLY VALUES OF COEFFICIENT OF VARIATION FOR
TOTAL PHOSPHORUS REMOVAL BY EACH TERTIARY UNIT
PROCESS AND BY TERTIARY TREATMENT SYSTEM.
45
-------
% CV values is as follows;
20 Highly consistent
20-39 Fairly consistent
40-59 Inconsistent
60 and above Highly variable to unpredictable
The performance of the first-stage lime clarifier was highly consistent in
each month. The second-stage total phosphorus removal was highly consistent
to fairly consistent except for July and March. The performance of all three
units in series was highly consistent. The performance was particularly smooth
in the last seven months due largely to improved process control.
46
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SECTION VI
SLUDGE TREATMENT AND DISPOSAL
A. Sludge Handling
Biological sludge from the secondary clarifier was recirculated to the head of
the secondary plant and resettled with raw sludge in the primary sedimentation
basin. During the initial months of study, the combined primary/secondary
sludge was pumped to the digester, and then to the tertiary thickener. At
average sludge flows, detention time in the 225 m3 (59,500 gal) thickener was
50 hours. In an emergency the sludge could be pumped to one of two 284 m3
(75,000 gallon) sludge holding tanks (Figures 4-1 and 4-2, and A-l.) In June
1973 the digester failed and the combined primary/secondary sludge was re-
routed directly to the tertiary thickener. Within the next few months piping
modifications were made which permitted the piston pump to replace the centrif-
ugal sludge pump. Through these changes, the volume of combined primary/sec-
ondary sludge could be calculated from the pumping rate by knowing the length
of the piston stroke, strokes per minute, and pumping duration.
Chemical sludge from the two lime clarifiers normally was pumped to the ter-
tiary thickener by two, variable speed, progressive cavity pumps (Figures 4-2
and A-6), Alternatively, the chemical sludge could also be pumped directly to
the vacuum filter, to the sludge holding pond, or to the tank truck loading
area.
The tertiary thickener supernatant was returned to the head of the trickling
filter plant via the filter backwash equalization tank and lift station #1
(Figure 4-2). Normally, the sludge thickener underflow was conditioned with
lime and pumped to the vacuum filter. However, the thickener underflow could
also be discharged to a tank truck without vacuum filtering or to the sludge
holding pond (Figures 4-2 and A-6). After vacuum filtration, the sludge cake
was conveyed to a truck for ultimate disposal. The vacuum filter filtrate,
belt wash water, and vat rinse water were returned to the filter backwash
equalization tank and pumped by lift station #1 to the head of the trickling
filter plant.
B. Sludge Thickener Influent Characteristics
An average of 13 m /day (3360 gpd) of combined primary-secondary sludge was
pumped to the thickener from November 1973 (when the piston pump was in-
stalled) through March 1974 (Table 6-1).
47
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TABLE 6-1 BIOLOGICAL AND CHEMICAL SLUDGE FLOWS TO TERTIARY SLUDGE
THICKENER
April 1973
May
June
July
August +
September +
October +
November
December
January 1974 +
February +
March +
Monthly
Average
Combined
Primary/Secondary
Sludge
(gallons/month)
*
*
*
*
*
*
*
101,000
104,000
104,000
94,000
104,000
Volume
(gallons/month)
348,000
588,000
623,000
1,043,000
916,000
777,000
827,000
664,000
1,012,000
1,019,000
718,000
737,000
Chemical
Sludge
Percent from Percent from
1st Stage 2nd Stage
Clarifier Clarifier
77
81
79
51
69
74
23
19
21
49
31
26
101,000
773,000
70
Sludge volume not directly quantified
Daily average sludge flow to thickener:
Primary sludge - 3,360 gpd
Chemical sludge - 1st stage clarifier 17,900 gpd
Chemical sludge - 2nd stag clarifier 7,500 gpd
30
48
-------
The volume of chemical sludge pumped from the tertiary clarifiers averaged
96 m3/day (25,400 gpd). This amounted to 2.2 percent of the average daily
wastewater flow. As seen in Table 6-1, sludge withdrawal from the lime clari-
fiers varied from month to month. It ranged from 44 m3/day (11,600 gpd)
during plant startup to 127 m3/day (33,600 gpd), About 70 percent of the total
chemical sludge volume came from the first-stage clarifier; the remainder from
the second stage. The percentages derived are based on the hours of pumping
and are not adjusted for the pumping speed which was usually, but not always,
the same for both underflow pumps.
The total sludge flow to the thickener (Table 6-1) averaged 109 m3/day
(28,760 gpd) of which 13 m3/day (3360 gpd) represented combined primary/sec-
ondary sludge, 68 m3/day (17,900 gpd) was from the first-stage lime clarifier
and 28 m3/day (7500 gpd) was from the second-stage clarifier.
Operating experience demonstrated that variations in the volume of primary/sec-
ondary sludge had a much greater effect on thickener performance than varia-
tions in the amounts of chemical sludge. The. combined primary/secondary sludge
discharged to the thickener averaged 7 to 10 percent solids.
The monthly mean solids concentrations of the chemical sludge ranged from 0.8
to 1.1 percent in the first-stage underflow and from 0.3 to 3.5 percent in the
second stage as shown in Table 6-2. From 35 to 51 percent of the chemical
sludge was calcium as Ca+2. In the first stage the calcium concentration was
4 to 5 g/1 and in the second stage 11 to 18 g/1. The iron (Fe+3) concentra-
tion in the second-stage underflow was 1 to 2 g/1 or about 10 times the iron
concentration in the first-stage underflow. Total phosphorus concentration
averaged 0.17 to 0.27 g/1 in the first-stage underflow and about 20 percent of
that in the second-stage underflow.
From a quantitative standpoint, the chemical sludge data in Table 6-2 should be
used cautiously since manually-composited sludge samples are only semi-repre-
sentative of actual chemical sludge. But from a qualitative standpoint, some
observations can be made. The second-stage underflow SS were relatively dense
in February and March which was probably due to the heavy calcium carbonate
sludge. On the other hand, low solids concentrations, as occurred in January,
may have resulted from "coning." "Coning" occurs when sludge withdrawal, nor-
mally on a periodic pumping basis of 5 minutes per hour, creates a draw-down
profile in the sludge blanket through which clarified wastewater is also drawn
into the suction line of the underflow pump. "Coning" was eliminated by tem-
porarily speeding up the sludge rake and continuously withdrawing sludge for
about 30 minutes.
C. Tertiary Thickener Performance
The thickener supernatant was sampled and analyzed for suspended solids, pH,
calcium, and total phosphorus. These analyses describe the degree of clarifi-
cation provided by the thickener and also point out the composition of a large
portion of wastewater that was returned to the head of the trickling filter
49
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TABLE 6-2
CHEMICAL SLUDGE CHARACTERISTICS* (mg/1)
1974
January
February
March
First Stage Underflow
Total P SS Ca++
260 8,330
177 9,660 4,940
268 10,900 3,870
Iron**
79
99
156
Second Stage Underflow
January
February
March
Total P SS Ta++
59 3,150
65 35,570 18,240
45 24,730 11,040
Iron**
269
1,580
1,750
* Results based on three samples per week except for iron
** Samples analyzed for iron once per week
50
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plant. The monthly averages for the four parameters are shown in Table 6-3.
The thickener overflow was typically very high in solids, the S^month mean
being 14,8 g/1 with a range of O.ll'g/1 to 28.8 g/1. The high solids concen-
tration led to plugging of the overflow weir, which in turn led to short-cir-
cuiting. Withdrawal of sludge for vacuum filtration temporarily improved the
quality of the thickener overflow, but as soon as sludge withdrawal and vac-
uum filtering stopped, the overflow again increased in solids concentration.
Operating experience demonstrated that without the primary/secondary sludge
from the primary clarifier the thickener overflow was relatively low in solids,
and the chemical sludge settled rapidly in the thickener. This was observed
on several occasions when the combined sludge from the primary clarifier was
not pumped to the thickener and a well-clarified thickener overflow was pro-
duced within a few days. Jar tests also illustrated the relatively poor set-
tling character of the undigested primary/secondary sludge. The addition of a
polymer, Betz DK-522, to the undigested primary/secondary sludge appeared- to
improve settling in the thickener.' However, Betz DK-522 was available for
only a brief time because of inadequate supplies.
In practice, the thickener was operated to maximize the underflow solids con-
centration while avoiding septic conditions in the thickened sludge.
D. Vacuum Filtration and Landfill Disposal
The solids concentration in the underflow was greatest during the first hour of
pumping the underflow to the vacuum filter and varied between 15 percent and
36 percent. As the sludge continued to be withdrawn for the duration of vac-
uum filter operation, the underflow solids concentration decreased. When the
underflow concentration had decreased to 5 percent to 8 percent, the vacuum
filter was shut down.
The vacuum filter was operated to produce a sludge cake of at least 30 percent
dry solids without using excess amounts of lime for conditioning. An operating
procedure was established whereby the filter operation began at the same time
of day, 6 days each week, and remained in operation until the filter cake
solids had decreased to 32 percent. Through this mode of operation, the filter
cake dry solids averaged 35.7 percent for the reporting period.
The vacuum filter performance for the first year of operation is shown in
Table 6-4. The yield averaged 49 kg/m2/hr CIO Ibs/sq,ft/hr) and the sludge
production averaged 690 kg/hr (0.72 tons/hr) on a dry weight basis with lime
addition. The minimum average yield was 27 kg/m2/hr (5.6 Ibs/sq.ft/hr) when
lime conditioning was not employed. The maximum yield with lime addition was
79 kg/m2/hr (16.2 Ibs/sq.ft/hr). Figure 6-1 shows that the filter yield varied
directly with the feed solids level except for the month of July. This apparent
inconsistency was a result of increased chemical sludge production resulting in
high initial thickener underflow concentration for the first hour of vacuum
filter operation. This led to the production of very thick filter cake (1 to
1 1/2 inches compared to normal cake thickness of 3/8 inch) for the first hour
of vacuum filter operation, thus increasing the average filter yield. In April
and May the combined primary/secondary sludge was digested prior to combining
51
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TABLE 6-3 TERTIARY SLUDGE THICKENER OVERFLOW CHARACTERISTICS
Month
August 1973
September
October
November
December
January 1974
February
March
Average *
Average +
Total Phosphorus
(mg/1)
404
1.88
117
392
489
407
414
318
318
363
Suspended Solids
(mg/1)
28.8
.106
8.9
20.3
19.1
10.2
17.4
13.7
14.8
16.9
Calcium
(mg/1)
842
103
374
802
882
598
926
1,570
762
856
pH
9.76
9.62
11.00
9.66
9.45
9.51
9.31
9.20
9.69
9.70
* Average of data from August 1973 through March 1974
+ Average does not include data of September 1973.
52
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TABLE 6-4 VACUUM FILTRATION OF COMBINED PRIMARY/SECONDARY AND CHEMICAL SLUDGES
APRIL 1973 THRU MARCH 1974
Parameter
Yield - Ibs dry solids/sq ft/hr
Drum Speed - min/rev
Operating Time - hrs
Feed Solids - percent
Cake Solids - percent
Wet Product - tons/hr
Dry Product - tons/hr
Total Wet Yield- tons
(including lime)
Total Dry Yield- tons
(including lime)
Lime Dose- Ibs/ton dry solids
Lime Usage - Ibs
April
1973
5.6
5.29
116.5
15.0
31.9
1.32
0.42
151
49.2
0
0
May
8.4
5.60
71.0
16.0
39.0
1.55
0.64
108
43.5
41
1775
June July October November December January
1974
10.4 14.1 16.2 12.04 11.7 8.33
3.95 2.19 2.76 2.49 2.69 3.81
99.5 149.0 110.0 116.0 102.4 137.1
16.4 13.2 17.8 18.0 16.6 13.3
39.2 38.0 39.1 36.9 35.5 33.0
1.98 2.71 3.10 2.42 2.45 1.67
0.78 1.06 1.32 0.90 0.88 0.56
226 399 333 286 246 224
87.4 155.0 133.0 105.8 87.5 72.7
95 61 34 49 57 76
8275 9510 4000 4300 4950 6800
February March 10-Month
Average +
7.1 6.56 10.04
3.85 3.70 3.60
88.9 85.3 1076.3 *
14.0 11.6 15.2
31.1 33.7 35.7
1.71 1.33 2.02
0.53 0.49 0.76
149 114 2180 *
46.6 39.7 820 *
72 62 61
2825 2350 44,785 *
* Ten-month total
-------
E
O 4
UJ
Ul
CL
1/1 2
5
o
s °
* 15
£>
Q 10
I I
18
fe?
crT 16
a
O 14
12
10
0
KEY: \
7 (•) No lime conditioner used.
1 1 1 1 1 1 1 1 1 1 |
-Is
o« < *
0 S-
"- S
FIGURE 6-1. MONTHLY AVERAGES OF FEED SOLIDS CONCENTRATION,
FILTER YIELD, AND DRUM SPEED FOR VACUUM FILTRATION OF
LIME CONDITIONED COMBINED BIOLOGICAL-CHEMICAL SLUDGE.
54
-------
with the chemical sludge for thickening and vacuum filtration. In June 1973
the sludge digester broke down and has not been in operation since that time.
Consequently, the combined primary/secondary biological sludge is not being
digested prior to thickening and vacuum filtration.
As previously stated, the -filter was operated to produce a sludge cake of at
least 30 percent dry solids. This was to meet a State requirement of a mini-
mum cake solids concentration of 30 percent necessary for the disposal of this
sludge to landfill. The filter operation produced a sludge cake of 35 percent
solids or better. For 10 months, the cake mean dry solids content averaged
35.7 percent (Table 6-4), ranging from 31.1 percent to 39.2 percent. During
April 1973, when no lime conditioning agent was added, the cake solids aver-
aged 31.9 percent.
An average of 74.4 metric tons (82 tons) of sludge (dry weight) was vacuum
filtered each month. The total production for the year was approximately 893
metric tons (984 tons) of sludge including 24 metric tons (26 tons) of lime.
Production ranged from 36 metric tons (40 tons) to 141 metric tons (155 tons)
per month. Increased sludge production in the summer months resulted from
increased wastewater flows and increased chemical dosages. For example, lime
dosage (CaO) to the first-stage lime clarifier was only 282 mg/1 in February
(43 metric tons sludge produced) but was 340 mg/1 in July (141 metric tons
sludge produced).
Table 6-4 also shows that for 10 months, the total wet sludge production was
1978 metric tons (2,180 tons). From April 1, 1973 to March 31, 1974 disposal
of this sludge required 350 trips to the sanitary landfill. Using 6.8 metric
tons (7.5 tons) as a typical truckload, 20 trips were made to the landfill in
February compared with 53 trips in July.
During the 12-month operating period from April 1, 1973 to March 31, 1974, the
vacuum filter produced 893 metric tons (984 tons) of dry solids including 24
metric tons (26 tons) of hydrated lime. The average filter yield was 49 kg/m2/hr
(10.0 Ibs/sq ft/hr). The filter sludge cake was typically 35 percent dry sol-
ids. The dry solids content was at least 30 percent in greater than 95 percent
of the truck loads. A higher rate of sludge withdrawal from the primary clari-
fier should improve vacuum filtration by eliminating septic sludge. The vacuum
filter operation is considered to have been satisfactory; however, the clarity
of the thickener supernatant was•considered marginal.
55
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SECTION VII
OPERATION AND MAINTENANCE
A. Personnel Organization and Tasks
The tertiary plant personnel consisted of 13 people. There was a plant engineer,
an operator supervisor, a plant foreman, a maintenance and boiler operator, and
nine tertiary plant operators. Three additional employees operated the trick-
ling filter plant and performed in-plant and up-stream maintenance and repairs.
The tertiary plant maintenance and repair work was performed by the maintenance
person, plant foreman, and City of Ely chief operator. Sample preparation and
collection was the responsibility of the plant foreman or one; operator-helper.
Safety was the responsibility of project safety officer, plant foreman, and
plant engineer. Operator supervision, pay records, purchasing, clerical, and
some maintenance were the duties of operator supervisor. Staff meetings, pro-
cess control, overall supervision, written summaries, and quarterly and annual
reports were the responsibility of the plant engineer.
Day-to-day operation of the tertiary plant was the duty of the EPA operators
and operator-helpers. Two operators were on hand 24 hours per day, seven days
per week in the tertiary plant. Each shift included one trained operator and
one operator-helper.
The duties of the shift operators were operating the tertiary' plant, operating
the vacuum filter, and other assigned tasks. Once each hour an operator col-
lected and composited samples at five locations and recorded totalizer readings,
wet well levels, chemical feed rates, pH meter readings, and solid blanket
levels. The clarifier mix zone percent solids test was set up on the half-hour
and read on the hour. Chlorine residuals were determined every two hours.
Every four hours the temperature, gravity filter pressure loss, and effluent
clarity were recorded, and the thickener overflow was sampled. The operators
adjusted wastewater flow rates, chemical feed rates, recirculation flow, and
sludge withdrawal rates as needed. Operators inspected lime slakers for exces-
sive lime buildup.
Almost all mechanical and electrical systems were tied into the main control
panel. When a piece of equipment failed, a light and an annunciator alerted the
operator. The operator was expected to perform minor repairs as needed. If
repairs could not be made by the operator, the plant staff was notified.
56
-------
The operators kept a log of all readings and recordings, but significant devel-
opments were written in a separate log book. The written log book included any
change in chemical dosages, equipment breakdowns or repairs, and unusual obser-
vations.
The vacuum filter, while in operation, required full time attention of one
operator. This operator prepared the lime for conditioning and started the
vacuum filter. While the filter was operating, samples of the influent and the
dry cake were collected for solids analysis. The operator saw to it that the
lime additon was correct, that the sludge depth in the vat was maintained, that
the filter cloth was straight, that the sludge cake formed was dry, and that
the sludge cake did not stick to the cloth. The operator emptied the sludge
into the truck for ultimate disposal at the sanitary landfill.
Additional duties performed by the operators included cleaning the bar screen
and checking the trickling filter plant when the City of Ely operators were off
duty. Operators inspected the three lift stations and pumps in the vicinity of
the tertiary plant. In addition, each operator shift was assigned a cleaning
and maintenance schedule.
B. Plant and Equipment Problems
Major Equipment Breakdowns
The major equipment problems experienced during the first year of operation of
the Ely plant included the second-stage lime clarifier, the sludge thickener,
the boiler, and the secondary clarifier. A description of each failure and the
corrective action taken is given below.
Second-Stage Lime Clarifier - Both the first and second-stage lime
clarifiers are equipped with a double shaft driver for the impeller and sludge
rake as shown in Figure A-4. A water-lubricated fiber bearing separates the
impeller shaft from the shaft of the sludge rake.
In October 1973 the fiber bearing developed an unusual noise. Upon investi-
gating the cause, it was determined that a pipe which supplied lubricating
water to the fiber bearing had failed because of inadequate support. When the
water pipe was repaired, additional pipe supports were used. However, damage
to the fiber bearing had resulted, and within five months it was necessary to
replace the bearing because of excessive wear.
On another occasion a high-pitched noise developed in the second-stage clari-
fier. Upon investigation, it was determined that two grease fittings located
near the top of the sludge scraper main shaft had not been properly serviced.
The result was that the main-shaft bearings were not being lubricated. Once
the grease fittings were installed, proper lubrication was applied to the
bearings and the high-pitched noise was no longer heard.
57
-------
In March 1974 vibrations developed in the second-stage lime clarifier. The
vibrations became severe enough to take the clarifier out of operation and to
drain it for inspection. Upon inspection, it was found that the mid-joint
fiber bearing was loose and that the sludge agitator paddle had twisted 90
degrees. With the assistance of a millwright a new fiber bearing was installed
and a new sludge agitator paddle was constructed to replace the one which was
damaged.
Tertiary Sludge Thickener - On two occasions repairs were required on
the tertiary sludge thickener. On one occasion unusual noises suddenly devel-
oped in the thickener. Before the thickener could be inspected, the shaft of
the hydraulic jack snapped. This jack was used to adjust the operating depth
of the sludge rake. Extensive repairs to the jack were completed at the fac-
tory and new parts including a new fiber bearing and larger washer, roller
bearing and pin were installed. It was also necessary to machine a large cyl-
inder and the shaft of the rake mechanism since both these parts had been
scored.
Before two months elapsed, noises from the thickener were again heard. When
the thickener was drained and inspected the noises were found to be caused by
the bearing assembly which was binding on the thickener bridge. The resulting
damage, which was a slight scoring of the inside surface of the cylinder sur-
rounding the bearing assembly, was minimal. Adjustments were made to prevent the
bearing assembly from binding on the bridge and no further difficulties were
experienced.
Boiler - The boiler used to heat the tertiary building was equipped
with an automatic low-water cut-off switch which shuts off the boiler when
water service to the boiler is interrupted. In November 1973 the automatic cut-
off failed to function which allowed a "dry-firing" of the boiler. The exces-
sive heat which resulted from insufficient water warped 52 of the heat exchanger
tubes. Because it was wintertime, emergency repairs were made immediately. In
the following March all the damaged boiler tubes were replaced,
Secondary Clarifier - In the biological treatment plant, the scum rake
in the secondary clarifier fell off its track which caused damage to the scum
rake and bull gear. When repairs were being made, cracks in the clarifier floor
were found. The cracked protion of the clarifier floor was repaired, the scum
rake repaired, and a new bull gear was installed.
Comminutor and motor - The communitor which had been added to the head
of the secondary plant when the tertiary plant was constructed was repaired at
a cost of almost $2,000. After only two years of operation it became necessary
to replace all the cutting teeth and shear bars. The comminutor motor also
burned out and had to be replaced. While the unit was out of operation for re-
pair, a rag problem developed which resulted in repeated plugging of the thick-
ener underflow pumps. This problem was temporarily circumvented by removing rag
debris by three bar screens located in series in the grit chamber of the second-
ary plant.
58
-------
Sludge pumps - The Moyno pumps, which removed thickened sludge from
the tertiary thickener, regularly became plugged with rags. This problem was
aggravated when the comminutor was out of service. The rag problem increased
the wearing rate of the stators. The stators on all four sludge pumps were
excessively worn within 1 1/2 years of operation and the installation of new
stators was required.
Polymer Mixer - For three months a polymer; Betz 1150, was mixed auto-
matical ly~with~a~liiechahical mixer. The mixer required excessive cleaning and
maintenance because the dry polymer feed opening, which was installed in the
mixer, regularly became plugged by wetted polymer particles. After using the
mixer for three months, the practice was discontinued. Thereafter, the
polymer was periodically batch-mixed in a day tank, which resulted in an effi-
cient, low-maintenance, operation.
Miscellaneous repairs - The minor repairs required included the
following:
(1) The carbon dioxide primary regulator leaked and had to be tightened with
new bolts.
(2) The wear plate on the vacuum filter had to be replaced frequently.
(3) Factory repair of the chlorine detector and the torque overload control
on the first-stage lime clarifier sludge scraper was required.
Design Considerations
Hindsight demonstrates that many changes and additions could have been designed
into the tertiary wastewater plant to improve plant operation and reliability
of equipment. During the first one and one-half years of operation, a number
of process modifications and safety improvements were made. Among them are the
following:
(1) C02 feed pipe - During the first months of operation the wastewater influ-
ent pipe to the second-stage lime clarifier became completely plugged with
calcium carbonate. To correct the situation, the CO 2 line, which had been
feeding into the influent pipe, was moved so that CO- could be fed directly to
the mix zone of the second stage. This eliminated tne buildup of CaC03 in the
pipe between the first and second-stage lime clarifiers.
(2) Boiler - Two smaller boilers should have been provided instead of one
large boiler for heating the Ely plant. The winter temperature in Ely, Minne-
sota can reach -40°C (~40°F) or lower, and a boiler failure in such weather
could cause extensive damage to the tertiary plant. Recognizing this risk,
turbine heaters and electric heaters were purchased in October 1973 for emer-
gency heating. On November 15 the boiler failed in moderate subfreezing wea-
ther, but the emergency heaters provided sufficient heat. Had the temperature
been extreme, the turbine and electric heaters would probably have been inade-
quate. In such a situation and with a two boiler arrangement, one boiler could
prevent the tertiary plant from freezing if the other boiler had failed.
59
-------
(3) Vacuum filter lime conditioning agent - No provisions ?iad been made in the
original design for feeding a sludge conditioning agent to the vacuum filter.
When it was determined lime conditioning was necessary, a day tank, pump,
mixer, and related equipment were installed in the vacuum filter room as an
interim lime-feeding system. For the permanent system the lime slaker dis-
charge piping was modified to allow slaked lime to be pumped to the day tank
in the vacuum filter room.
(4) Ventilation in the VF room - No exhaust fan had been included in the de-
sign of the filter room. A large stand-up fan, exhausting to the main plant,
was added and provided very good ventilation.
(5) Glass piping - Glass piping which was used to feed sulfuric acid and fer-
ric chloride proved to be both unreliable and dangerous. Occasionally a length
of glass pipe would break and fall to the ground, or a glass valve would break
off while being turned. Maintenance personnel could not work near the glass
piping for fear of breaking it. As a result, sulfuric acid piping was replaced
with CPVC piping and ferric chloride lines were replaced with CPVC tubing.
(6) Storage - Two new storage areas were developed. (a) A metal shed was
constructed to store spare parts, tubing, piping, tanks, welders, fittings, etc.
(b) The carbon storage room was divided to create a storage area for laboratory
chemicals in one section and powdered carbon in the other.
(7) Water hammer - In general, tertiary plant effluent was used for the
757 m-Vday (200,000 gpd) process water required in the tertiary plant. City
water was used for process water only one percent of the time. On those occa-
sions, however, a water hammer was created that damaged hot water heaters in
the vicinity of the Ely plant. A pressure relief valve was put ahead of the
break tank to protect against the water hammer. The relief valve ended further
damage to the hot water heaters, although fluctuations in water pressure con-
tinued when the city supply was used for tertiary process water.
(8) Additional modifications were made or were suggested to improve operation
of the Ely plant. (a) The plant effluent totalizer range was increased from
11,356 m3/day (3.0 mgd) to 18,925 m3/day (5.0 mgd) in order to record flows
that bypass the tertiary plant. (b) A wet well level indicator was installed
in the operator control room. (c) Controls to activate the sludge hopper
doors were repositioned to improve plant safety and maintenance. (d) Individ-
ual underflow metering devices for each lime clarifier are recommended to re-
place the combined underflow totalizer. (e) Chemical feed pumps should be con-
nected to the emergency power source. (f) The capacity of each of the two
effluent recycle pumps should be greater, since one pump was inadequate about
half the time. (g) The probe for the high-level alarm on the CaO bins was too
short to provide sufficient warning when filling the CaO bins. The probe has
been lengthened. (h) Tertiary plant effluent water is now used for all non-
potable purposes except polymer makeup. This has resulted in a considerable
savings in costs.
Despite these design and equipment difficulties, the processes and equipment
performed well enough to meet the design effluent total phosphorus requirements.
60
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C. Maintenance Requirements
Routine maintenance duties were performed by the City of Ely operators, EPA
operators, and EPA day shift personnel. The City of Ely operators shoveled
snow in the winter, cut the grass in the summer, and kept the wastewater plant
grounds orderly. The city operators cleaned the bar screen and grit chamber,
cleaned the trickling filter distributors and moving parts, inspected and re-
paired the secondary plant pumps, and lubricated all secondary plant pumps and
mechanical equipment. The city operators assisted the EPA personnel with the
tertiary plant maintenance, thereby familiarizing themselves with the tertiary
plant equipment.
Maintenance of the trickling filter plant and the tertiary plant was the re-
sponsibility of the day shift personnel. Each week the plant engineer compiled
a list of maintenance problems. The operator supervisor, the foreman, the
maintenance man, and the City of Ely chief operator saw to it that required
maintenance was performed. The routine maintenance duties included cleaning
out plugged sludge pumps; lubricating equipment; ordering spare parts; repair-
ing or cleaning hoses, pipes, tanks, fittings, valves, stand pipes, and rota-
meters; and performing some custodial duties. The day shift personnel oper-
ated a welder, torch, grinder, compressor and other equipment needed in making
repairs. The vacuum filter required maintenance which included lubrication,
sewing and glueing replacement filter cloths, replacing filter springs, chang-
ing the wear plate, removing lime scale from the filter grids and drum, and
repainting the drum. The filter cloth was changed three times in the initial
five months; however, the most recent filter cloths lasted six and seven months,
respectively.
The shift operators contended with high maintenance items as the lime slakers,
chemical feed pumps, and underflow pumps. The operators cleaned around the
slaker paddle shaft and weigh belt, and checked the lime paste consistency
every four hours. The lime feed piping, particularly the valves and the ejec-
tors, became plugged or coated with lime and had to be disassembled and cleaned.
The operators replaced valves, gaskets, diaphragms, etc. in the chemical feed
pumps as the parts wore out. Operators unplugged the thickener underflow pumps
that regularly bound with rags or heavy sludge. The chemical sludge underflow
pumps on occasion required both unplugging and replacement of shear pins.
Preventive maintenance performed by the operators involved inspecting the pack-
age lift stations, lubricating some equipment, checking and sometimes bleeding
the influent pumps and effluent recycle pumps, inspecting the powdered carbon
unit, testing for chlorine leaks, observing the temperature of the chlorine
room and the emergency generator room, and checking the boiler.
The custodial duties of the operators were mopping halls and floors, hosing
down the floors in the main process area, the chemical rooms, the dry wells,
and the gravity filter pit, cleaning the vacuum filter room and equipment,
cleaning the truck room, and general housekeeping.
The distribution of operation and maintenance duties is shown in Table 7-1.
61
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K)
TABLE 7-1 MANPOWER REQUIREMENTS FOR ELY AWT PLANT
MAN -YEARS/ YEAR
Unit Process Admins.
Grit Chamber and Comminutor
Secondary Treatment **
First-stage lime clarifier
Second-stage lime clarifier
Gravity filters
Other process equipment
Lime storage and feeding
Ferric chloride, sulfuric acid, polymer
Carbon dioxide, chlorine
Underflow pumps
Sludge Thickener
Vacuum filter
Sludge disposal
Tertiary Building Systems
Emergency Generator
Plant Grounds
Sample collection and preparation
Laboratory analysis .60
Administration 1 . 20
Process control and data analysis .60
Reports .40
Operation
.29
.25
.77
.78
.09
1.00
.18
.40
.47
.08
.06
1.15
.29
Prev.
Maint.
.02
.11
.06
.06
.05
,20
.25
.15
.14
.02
.03
,06
.02
.35
.08
.04
.15
Corr.
Maint .
.04
.54
.02
.11
.06
.20
.22
.05
.04
.90
,11
.09
,04
.15
.02
.20
.14
.15
Sampling
§ Analysis Custodial Total
.35
.90
.85
.95
.20
1.40
.65
.60
.65
1.00
.20
1.30
.35
1.15 1.65
.10
.30 .50
.92 1.10
2,80 3.70
1.20
.60
.40
Totals
2.80
5.81
1.79
3.08
3.72
1.45
*
**
1 man-year = 2080 hours
primary settler, trickling filter, and secondary settler
18.6
-------
Maintenance - Electrical, Boiler, and Instruments
The duties of the designated maintenance man involved electrical work, instru-
mentation, heating, air-conditioning, and ventilation. Besides routine duties,
the maintenance man installed electrical conduit and did some welding. The
maintenance man was assisted by other personnel as needed.
Electrical work included checking and greasing motors in both the trickling
filter plant and tertiary plant, along with maintaining motor controllers, the
diesel emergency generator, and the gravity filter backwash cycle and valve
sequence.
Any instrumentation such as calibrating pH meters, the flow proportional sys-
tem, and flow meters was the responsibility of the maintenance man.
During the heating season the boiler was regularly inspected for C02, smoke
and draft. Every two weeks low and high water cut-offs were tested. Filters
to the air exchangers, the boiler air supply, and the air-conditioning system
were changed as needed. Steam traps were inspected and cleaned every other
season. The maintenance man was expected to perform his duties without spe-
cific supervision.
Safety
The purpose of the safety program at the tertiary wastewater plant was to
create safety awareness, maintain a safe work area, provide safety training,
and seek participation by all personnel in safety discussions and in detection
of hazards.
A safety committee, including the tertiary plant foreman, was established and
acted to bring all work areas, including the tertiary plant building, up to at
least OSHA standards. As part of directing the safety program, the safety
committee inspected work areas for hazards, put up posters concerning safety,
organized first aid courses, encouraged good housekeeping to prevent accidents,
and made recommendations to eliminate hazards in the working environment.
In order to reduce safety hazards in the tertiary plant, the following actions
were taken. An access platform was constructed around the vacuum filter,
safety showers and eye washes were installed in the laboratory and next to the
sulfuric acid pump; glass piping for sulfuric acid and ferric chloride was re-
placed with CPVC piping; alarms for evacuation were mounted at five locations
in the tertiary plant building; defective guards on machinery were replaced or
repaired; steel mesh and non-slip tape were attached to slippery surfaces; and
a railing was constructed around a drywell manhole as a substitute for a warn-
ing chain. Life jackets, safety lines, and harnesses were purchased for work-
ing above clarifiers. Rubber suits and an acid resistant hood were obtained
for handling sulfuric acid. Hard hats and ear plugs were also purchased. The
wearing of hard hats was required for anyone in the process area of the ter-
tiary plant.
63
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The safety committee as a group Inspected the tertiary plant periodically;
however, one safety committee member checked for hazards in the plant each
week. The weekly inspection included checking fire extinguishers, safety
showers, and the self-contained breathing apparatus. On one inspection dead
flies were discovered blocking the air-flow to the mask of the self-contained
breathing apparatus. The plant was also inspected for safety deficiencies by
three safety experts from an insurance company.
Safety skills and awareness of personnel have been enhanced by various train-
ing courses and lectures. Two members of the safety committee attended one-
week courses in safety. Six of the plant personnel have received first aid
training at a 14-hour course sponsored by the Red Cross. Plant personnel par-
ticipated in a seminar on chlorine safety. Listening to tapes on safety,
safety meetings, evacuation drills and the distribution of memos and pamphlets
on safety were also part of the safety program.
64
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SECTION VIII
COSTS OF OPERATION AND MAINTENANCE
The costs required to operate the plant from April 1, 1973 through March 31,
1974 totaled $389,107.64. During this period 1.6 x 10& m3 (427.7 million
gallons) of wastewater were treated at a cost of $0.24/m3 ($0.91/1000 gallons).
The 12-months1 operating costs and the percentages for 27 categories are shown
in Table 8-1. The unit chemical costs and power costs are shown in Table 8-2.
The relative costs for personnel, chemicals, utilities, miscellaneous, and
equipment operation and repair are shown in Figure F-l. The five principal
cost categories are subdivided in Figures F-2 through F-6. The operational
cost breakdowns which are shown in Appendix F are based on the cost information
in Table 8-1.
Figure F-l points out that more than 60 percent of the operational costs were
for operating personnel. This reflects the need for a skilled staff. Chemical
costs, including shipping, amounted to 15 percent of total operational costs
or $58,000 per year. The cost of shipping in chemicals was high because of the
distance from chemical suppliers. Chemical usage, which was confined almost
entirely to the tertiary operation, was greater in the summer months while util-
ity costs, particularly fuel oil costs, were highest in the winter months.
Utility costs were 9.7 percent of total operational costs (Figure F-4). Miscel-
laneous supplies represented 5.8 percent of total costs (Figure F-5), and the
cost to operate and repair plant and equipment was 8.3 percent (Figure F-6).
Personnel costs are apportioned in Figure F-2. Operator salaries amounted to
about one-half of personnel costs and provided for two operators in the terti-
ary plant 24 hours per day, seven days per week. Two operators were required
at all times to ensure high performance of the wastewater treatment process and
for their own safety. Laboratory personnel performed a very large number of
analyses during the 12-month period of tertiary plant operation. The wastewater
stream was sampled daily at eight locations and the underflow streams were sam-
pled several times per week. The wastewater samples were tested for more than
a dozen parameters; some daily, some three times a week, and some weekly. Main-
tenance tasks were performed by the foreman, supervisor, and operators as well
as the maintenance-boiler man and assistant. The maintenance-boiler assistant,
along with the foreman, collected and prepared samples for the laboratory.
Figure F-3 indicates that 87 percent of the cost of chemicals was expended for
lime, carbon dioxide, and ferric chloride. The category., "Other Chemicals/'
included chiefly the cost of powdered carbon. During five months of operation
65
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TABLE 8-1
OPERATION AND MAINTENANCE COSTS FOR ELY WASTEWATER TREATMENT PLANT
APRIL 1973 THRU MARCH 1974
Category
Personnel (December 1974 waee
Operators
Maintenance S, Boiler
Foreman, Supervisor
Engineer
Laboratory
Accounting
Subtotal
Chemicals
CaO
Cl2
C02+Rental
FeCl3
H2S04
Poly
Other chemicals
Subtotal
Utilities
Electricity
Water
Heating-fuel oil, propane
Telephone
Subtotal
Supplies
Laboratory
Sampling
Custodial
Grease § oil
Subtotal
Equipment Operation £ Repair
Replacement S, spare parts
Misc. repair § maintenance
Equip, repairs £ maintenance
New Equipment - Structures
Safety Equipment
Sludge Truck 0£M
Subtotal
TOTAL COSTS
12 -month
Costs
rates)
116,215.34
30,608.67
30,291.81
14,696.00
45,000.00
1,678.00
238,489.82
15,406.04
1,655.25
18,606.51
16,459.39
2,815.89
1,931.96
1,195.03
58,070.07
20,088.54
440.47
15,653.77
1,553.50
37,736.28
20,450.00
1,743.92
232.76
145.58
22,572.26
16,497.36
7,777.67
3,702.29
2,517.68
906.44
837.77
32,239.21
389,107.64
Percent of
Category
48.7
12.8
12.7
6.2
18.9
.7
100.0
26.5-
2.9
32.1
28.3
4.8
3.3
2.1
100.0
53.2
1.2
41.5
4.1
100.0
90.6
7.7
1.0
.7
100.0
51.2
24.1
11.5
7.8
2.8
2.6
100.0
Percent Unit
of Total
-------
TABLE 8-2 UNIT COSTS OF CHEMICALS AND POWER FOR ELY AWT PLANT OPERATION
Chemical Costs
Lime: Low - $25.25 per ton
High - $32.77 per ton
Freight - included
Ferric chloride: Low - $80.00 per ton
High - $90.00 per ton
Freight - $40.08 per ton
Sulfuric acid: Low - $45.15 per ton
High - $50.90 per ton
Freight - included
Carbon dioxide: Low - $65.00 per ton
High - $75.00 per ton
Freight - included
Polymer (Betz 1150): Low - $2.38 per Ib.
High - $3.32 per Ib.
Freight - included
Power Costs
Electricity: Low - 2.05<^/kWh
High - 2.06<£/kWh
#2 fuel oil: Low - 23.6^/gal
High - 29.95*/gal
Propane: Low - 25.9
-------
ferric chloride was shipped in drums rather than by tank truck, which signif-
clTiy^nnnnaSed ^ C°St °£ ferriC chloride" The carbon dioxide costs in-
cluded $3,000 per year rental of a C02 refrigerator-storage unit.
The cost of water as shown in Figure F-4 was kept very low by utilizing ter-
water Pl3nt efflU6nt f°r &11 tertiary P^nt processes except polymer make-up
In Figure F-5, laboratory expenses, excluding laboratory personnel costs
accounted for almost all miscellaneous costs. Laboratory expenses were large
because considerable analytical work was necessary for research and quality
control in the tertiary plant.
Equipment replacement and spare parts totaled 51 percent of the total main-
tenance costs as shown in Figure F-6. A large spare parts inventory was
obtained to allow repairs to be made promptly and prevent downtime caused by
a slow delivery and/or shortage of parts. Some equipment required periodic
replacement of parts such as the underflow pumps and chemical feed pumps The
plant staff minimized repair and maintenance costs by making the repairs them-
selves. Repair costs were increased due to extensive repairs needed in the
20-year-old trickling filter plant. New equipment purchases included emergency
heaters, a storage shed, and a pump with a motor to route slaked lime to the
vacuum filter room.
68
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SECTION IX
REFERENCES
1. "Shagawa Lake Project: Lake Restoration by Nutrient Removal from Waste-
water Effluent," Environmental Protection Agency, Report No. EPA R3-73-
026, January, 1973.
2 Fair, G.M., Geyer, J.C., and Okun, D.A., Water Purification and Waste-
water Treatment and Disposal, John Wiley § Sons, Inc., 1968, pg. 30-11.
3. IBID, pg. 29-22.
4. Sawyer, C.N., and McCarty, P.L., Chemistry for Sanitary Engineers, McGraw-
Hill, Inc., 1967, pg. 292.
5. IBID, pg. 297.
69
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APPENDICES
APPENDIX A
TREATMENT PLANT LAYOUT PLANS AND DESIGN CRITERIA
70
-------
INFLUENT WET
WELL
INFLUENT PUMPS _j
CHLORINE
CONTACT
CHAMBER
SLUDGE DIGESTER
^ -X
TRICKLING
EFFLUENT i
METERING STATION
SLUDGE HOLDING POND |
Laboratory! ?_o>
II In U
, PRIMARY
11 CLARIFIER
kludge Thickener
Filter Backwash Equalization Tank j
(°) PACKAGE Lin
STA. NO. 1 i
SLUDGE
HOLDING
POND
DRAIN
Filter Backwash
SLUDGE
HOLDING
TANK
LIFT STA. NO. 2
=40 feet
STINKY DITCH
LEGEND
PROCESS
BYPASS
Flow Intercepting
Structure
COMMINUTER
PACKAGE LIFT
STATION NO. 3
•• *- Influent Sewer
^-—Syphon
Plant Influent
APPENDIX A, FIGURE A-1. WASTEWATER TREATMENT PLANT LAYOUT PLAN
-------
14" Reactivates
14" Overflow to Influent Wet Well No. 1 Bypass Magnetic Flow Meter
14" Overflow to
Influent Wet Well
^INFLUENT PUMPING STATION
EFFLUENT RESERVOIR
24" Effluent to Metering
& Sampling Station s/,~2~
• i 'i'
24" Tertiary Bypass _{., fl
14" Effluent Reservoir >
M '
14" Gravity Filter Bypass
8" Effluent Reservoir Drain-f,
16" Reactiva
No. 2 Bypass
16" Reactivator
No. 2 Effluent
Flow Splitter Box
Gravity Filter Units
1 1
.INFLUENT MANHOLE
'condary Effluent
|jJ«-24" Tertiary Bypass
APPENDIX A; FIGURE A-2. TERTIARY PLANT LAYOUT PLAN SHOWING WASTEWATER PIPING
-------
VARIABLE SPEED
SLUDGE SCRAPER DRIVE
COLLECTOR FLUME
TREATED WATER \
OUTLET
VARIABLE SPEED
RECIRCULATOR DRIVE
DRAFT TUBE
IPOLYMER FJJD
SLOW MIXING AND
FLOC FORMATION
SCRAPER ARMS
SLUDGE COLLECTOR PIT
6" SLUDGE DRAWOFF
»AiviMr WASTEWATER
RAPID MIXING INFLUENT
AND RECIRCULATION 'pNpFELUENT
IMPELLER
SLUDGE AGITATOR PADDLE
3" CLEANOUT
APPENDIX A, FIGURE A-3. FIRST STAGE LIME CLARIFIER
73
-------
VARIABLE SPEED
SLUDGE SCRAPER DRIVE
COLLECTOR FLUME
TREATED WATER
OUTLET
VARIABLE SPEED
RECIRCULATOR DRIVE
DISSOLVED C02 FEIED]
SLOW MIXING AND
FLOC FORMATION
SCRAPER ARMS
SLUDGE COLLECTOR PIT
6" SLUDGE DRAWOFF
RAPID MIXING WASTEWATER
AND RECIRCULATION INFLUENT
IMPELLER P'PE
SLUDGE AGITATOR PADDLE
3" CLEANOUT
APPENDIX A, FIGURE A-4. SECOND STAGE LIME CLARIFIER
74
-------
BACKWASH
COMPARTMENT
GRAVITY FILTER
EFFLUENT
FILTER
COMPARTMENT
24" THICK ANTHRACIH
BACKWASH
PIPE
GRAVITY FILTER
INFLUENT
FROM FLOW
SPLITTER BOX
VALVE U
VALVE A
VALVE C
APPENDIX A, FIGURE A-5. GRAVITY FILTER UNIT
75
-------
6" Sludge'to Sludge
Holding Pond
4" Sludge Pump
Discharge
6" Underflow
Pump Discharge
4" Sludge to Truck
Loading jj I
•4" Vacuum Vent fH ™l/s.
-Vacuum Filter | fj /
Sludge to Vacuum FilterA
U * •'
Sludge Conveyor
• W
•Sludge Hopper ( «
with Hydraulic Gatesfe—
<; -»•• Sludge \ 4" Filtrate to Backwash
I Thickener \JEqualization Tank
I Overflow 4" Filtrate tn Clurlno TkirLo^ar
\ -~ "-
4" Digested Sludge
to Sludge Thickener
APPENDIX A, FIGURE A-6. TERTIARY PLANT PLAN SHOWING SLUDGE PIPING
-------
APPENDIX A
Table A-l
DESIGN CRITERIA
1. Grit Chambers (2)
Velocity Control
Length
Width
Depth
2. Comminuter
Design Flow
Peak Flow
3. Primary Clarifier
Diameter
Sidewall Depth
Volume
Detention Time
@ 1893 m3/day (0.5 mgd)
§ 3785 m3/day (1.0 mgd)
@ 5678 m3/day (1.5 mgd)
Overflow Rate
@ 1893 m3/day (0.5 mgd)
@ 3785 m3/day (1.0 mgd)
@ 5678 m3/day (1.5 mgd)
Weir Length
Weir Overflow Rate @ 5678 m3/day
(1.5 mgd)
4. Trickling Filter
Diameter
Rock Depth
No. of Distributor Arms
Surface Area
Hydraulic Loading @ 5678 m3/day
(1.5 mgd)
5. Secondary Clarifier
Diameter
Sidewall Depth
Volume
Detention Time
§ 1893 m3/day (0.5 mgd)
@ 3785 m3/day (1.0 mgd)
@ 5678 m3/day (1.5 mgd)
Proportional Weir
10 m (32'-6")
0.9 m (3'-0")
1.2 m (4'-0")
5678 m3/day (1.5 mgd)
28,387 m3/day (7.5 mgd)
15.2 m (50')
2.4 m (7'-10")
473 m3 (16,700 cf)
6 hrs.
3 hrs.
2 hrs.
10 m/day (255 gpd/sq ft)
21 m/day (510 gpd/sq ft)
31 m/day (765 gpd/sq ft)
44.5 m (146')
128 m2/day (10,270 gpd/lf)
18.3 m (60')
1.8 m (61)
4
263 m2 (2830 sq ft)
21.6 m/day (530 gpd/sq ft)
15.2 m (50'-0")
2.1 m (6'-10")
417 m3 (14,700 cf)
5.3 hrs.
2.65 hrs.
1.77 hrs.
77
-------
Overflow Rate
§ 1893 m3/day (0,5 mgd) 10,4 m/day (255 gpd/sq ft)
8 3785 m3/day (1.0 mgd) 20.8 m/day (510 gpd/sq ft)
§ 5678 nrVday (1,5 ragd) 31,2 m/day (765 gpd/sq ft)
Weir Length 44 <8 m (U7 .)
Weir Overflow Rate 8 5678 m3/day 128 m2/day (10,270 gpd/lf)
(1.5 mgd)
6. Chlorine Contact Chamber
Length 12.8 m (42')
Width 4.8 m (16')
DePth 1.5 m (5')
Volume 95.12 m3 (3360 cf)
Detention Time
§ 1893 m3/day (0.5 mgd) 72 min.
§ 3785 m3/day (1.0 mgd) 36 min.
6 5678 m3/day (1.5 mgd) 24 min.
7. Solids Contact Unit No. 1 (Graver Reactivator No. 1)
Diameter 16.76 m (55')
Sidewall Depth 5.94 m (19'-6")
Volume
Mixing Zone 27.74 m3 (980 cf)
Flocculation Zone 92.0 m3 (3250 cf)
Clarifier Zone 1135.2 m3 (40,100 cf)
Detention Time
@ 5678 m3/day (1.5 mgd)
(Design Flow) 5.3 hrs.
8 11,355 m3/day (3.0 mgd)
(Hydraulic Design Flow) 2.65 hrs.
8. Solids Contact Unit No. 2 (Graver Reactivator No. 2)
Diameter 16>76 m (551)
Sidewall Depth 5 03 m (16,_6n)
Volume
Mixing Zone 23.21 m3 (820 cf)
Flocculation Zone 77>28 m3 (273Q c£)
Clarifier Zone 952.63 m3 (33,,650 cf)
Detention Time
§ 5678 m3/day (1.5 mgd)
(Design Flow) 4.45 hrs.
@ 11,355 m3/day (3.0 mgd) 2.23 hrs.
). Automatic Gravity Filters (Graver Mono-Scour Filters)
Number 4
Diameter 3.7 m (12.)
Unit Height 4.9 m (16t)
Filter Media Depths
Anthracite 0.61 m (24")
Sand 0.30 m (12")
Surface Area 10.5 m2 (113 sq ft)
78
-------
10.
11.
12.
Design Flow
Max, Peak Flow
Average Backwash Flow
Backwash Air Compressor
e 0,031 Pa (4.5 psi)
Motor (.1800 rpm)
Backwash Chamber Volume
Sludge Digester
Diameter
Sidewall Depth
Volume
Heat Exchange
Gas Compressor @0.055 Pa (8.0 psi)
Sludge Thickener (Graver Rota-Rake)
Diameter
Sidewall Depth
Volume
Design Flow
Detention Time §0-0037 m3/s (60 gpm)
Vacuum Filter
Diameter
Face Width
Surface Area
Drum Speed
Vacuum Pump @ 0.508
Motor (1750 rpm)
Filtrate Pump @ 11
Motor (1150 rpm)
0.0164 m3/s (260 gpm) per filter
0.00156 m/s (2.3 gpm/sq ft)
0.0249 m3/s (396 gpm) per filter
0.0023 m/s (3,5 gpm/sq ft)
0.11 m3/s (1690 gpm)
0,0101 m/s (15 gpm/sq ft)
0.26 m3/s (550 cfm)
15 hp
26.3 m3 (930 cf)
7.3 m (24')
4.51 m (15')
205.2 m3 (7250 cf)
300,000 BTU hr.
73.6 m3/hr (2600 cfh)
7.9 m (26')
5.029 m fl6'-6")
225.34 m3 (7960 cf)
0.0037 m3/s
16.5 hrs.
(60 gpm)
m (20")Hg
,58 m (38' TDH)
13.
Pumps No. HP.
Sewage
Recirculation 2 7.5
Influent 2 30.0
Effluent Water 2 15.0
Tert. Serv. Water 2 20.0
Sec, Serv. Water 1 1,5
Lift Sta. No, 1 2 10
Lift Sta. No. 2 25
Lift Sta, No. 3 23
Sludge
Primary (PD2) 1 2
Secondary 1 2
Digested 1 2
Recirculation (HE3) 1
Underflow 2 7.5
Transfer 2 7.5
1.8 m (61)
2.4 m (8')
13.93 m2 (150 sq ft)
0.14 to 0.94 rpm
0.2595 m3/s (550 cfm)
30 hp
0.0075 m3/s (120 gpm)
3 hp
RPM TDH ft. Design Flow (gpm)
1150
1150
3500
1750
1150
1150
1150
48.6
1150
1150
37
65
170
120
55
40
30
23
37
37
25
500
1100
150
300
200
100
100
85
50
50
150
Var. Speed (84-420)
Var. Speed (84-420)
TDH
- Total Dynamic Head 2Positive Displacement 3Heat Exchanger
79
-------
C. Sump Pumps
Influent
Drywell
Effluent
Drywell
Underflow
Drywell
Lift Sta. No,
Lift Sta. No.
Lift Sta. No.
No,
RPM TDH ft, Design Flow (gpm)
2
1
1
1
1
1/3
1/3
1/3
14. Chemical Feed Systems
A. Chlorine
Storage Units
Tertiary Chlorinator
Rotameter-Tertiary
Adjustable Range
@ 5678 m3/day (1.5 mgd)
Secondary Chlorinator
Rotameter-Secondary
Adjustable Range
@ 5678 m3/day (1.5 mgd)
B. Carbon Dioxide
Storage Unit (Cardox Rental)
Feeder
Rotameter
Adjustable Range
@ 5678 m3/day (1.5 mgd)
C. Lime
Storage (2 bins)
Gravimetric Slakers (2)
Capacity (Max. Each)
Accuracy
Range (Each)
@ 5678 m3/day (1.5 mgd)
Ejector Pumps (2) 36.57 m (120'
Motor (3450 rpm)
D. Powdered Activated Carbon
Storage Hopper
Volumetric Feeder
Range
@ 0.0657 m3/s (1.5 mgd)
Slurry Feed Pump @ 39.0 m (128'
Motor (3500 rpm)
Dust Collector
Motor
1725
1725
1725
46
46
46
18
14
14
50
50
50
21
34
34
68.02 kg (150 Ibs)
181.4 kg/day (400 Ibs/day)
90.7 kg/day (200 Ibs/day)
20 to 1
16 mg/1 to 0.8 mg/1
45.35 kg/day (100 Ibs/day)
20 to 1
8 mg/1 to 0.4 mg/1
21.8 metric tons (24 tons)
2721 kg/day (6000 Ibs/day)
2040.75 kg/day (4500 Ibs/day)
20 to 1
360 mg/1 to 18 mg/1
50.95 m3 (1800 cf)
453.5 kg/hr (1,000 Ibs/hr)
- n
0 to 453.5 kg/hr (0 to 1000 Ibs/hr)
0 to 1920 mg/1
TDH) 0.0378 m3/s (60 gpm)
5 hp
2.123 m3 (75 cf)
0.2095 m3/hr (7.4 cf/hr)
34 kg/hr (75 Ibs/hr)
20 to 1
144 mg/1 to 7.2 mg/1
TDH) 0.00144 m3/s (23 gpm)
5 hp
0.2359 nrVs (500 cfm)
3/4 hp
80
-------
E. Miscellaneous Chemicals
Acid Storage [66° Baume1)
Polymer Storage
Dry Storage (Portable Chemix)
Batch Size (Chemix)
Alum Room Day Tank
Alum Storage 22.6 m
Metering Pumps (4) 0.861 Pa (125 psi)
§ 0.0657 m3/s (1.5 mgd)
Motor (DC)
15. Plant Flow Meters
Trickling Filter -
Recirculation - Propeller
Chlorine Tank Effluent -
Rectangular Weir
Tertiary Plant Influent -
25.4 cm (10")Magnetic Meter
Underflow Sludge Flow Rate
7.62 cm (3") Magnetic Meter
Plant Effluent
Parshall Flume
228.6 mm (9") Throat
16. Emergency Generator
KW Rating @ 0.8 Power Factor
Engine Type 6 cylinder in line diesel
Engine Speed
Brake Horsepower Available
Fuel Consumption (100% load)
17. Boiler
Horsepower
Steam Production
Fuel Consumption (150,000 BTU/gal)
18. Fuel Oil System
Storage (Buried)
Generator
Boiler (2)
Boiler Fuel Oil Pumps (2)
Type
16,655.8 £ (4400 gal)
0.2547 m3 (9 cf)
94.61 £ (25 gal)
208.2 I (55 gal)
(800 cf) 22712.4 I (6000 gal)
5 to 79 I (1.3 to 20.8 gal)
0.87 mg/1 to 13.87 mg/1
1/4 hp
0.0126 to 0.1373 m3/s
(200 to 2180 gpm)
0.00067 to 0.01008 m3/s
(11 to 160 gpm)
0.0316 to 0.0945 m3/s
(500 - 1500 gpm)
200 kw
4 cycle
1800 rpm
311 hp
0.0617 m3/hr (16.3 gph)
200 hp
0.8687 kg/s (6900 Ibs/hr)
0.211 m3/hr (55.8 gph)
2119.83 I (560 gal)
30283.29 H (8,000 gal) each
Gear
81
-------
APPENDIX B
SCHEMATICS OF LIQUID AND SLUDGE FLOWS
82
-------
STP=City Secondary Wastewater
Treatment Plant
IF = lnfluent Tank
M = Flow Meter
CUi =#] Contact Unit
CU2=#2 Contact Unit
ST = Sludge Thickener
SVF = Sludge Vacuum Filter
ET = Equalization Tank
SB = Splitter Box
F = Gravity Filter
VW = Viewing Well
PF = Parshall Flume
SD = Stinky Ditch
SHP = Sludge Pond
SW = Swamp East Side of Plant
APPENDIX B, FIGURE B-l.
-------
Activated Corbon
Ba, Feed Hopp
j Gate Valve =^= Process Piping ^^ ^ I
* Ball Valve -4-i-f Process Bypass Piping, -----*- --'-_—a A. f
* Plug Valve Sludge Piping i '* f^^^~V LJ"ie Storage and Qt
-2£;± — ^tllo^Pipt9 MlLl_J'N.dH,p.B JLjh .
I Pres,ure Regulating Valve P 8 V/ V/ Chlorine n n _T Vaream.l.r 4 Carbon Dioxide Feeo
< Pressure Relief Valve T Y f Service Water Cylinders S Scale Jl| , Vent I Distribution Panels (,Vent.-Hea,
Tsrr:-1- oJ|[-5~^^ ch,or~!:i|54^p/ NSsJiJvL^
C"bo" _Jt Dust Collectors T f ^Jt ^"f-l'-t ^f!-^ ^ >_C"_", ~ "^.V-i __<_ Tff CO 2 Stom^eand
N Water Pump, ^ | ^Elector. | r<_^r.Sefvite Wo,,rS.,o,ess Water ' It 1 ? f f| H Corbon Dioxide Feed System
"ftBolometer -ifH; Lime Storage and Feed System ' "" S1°ro9e Tan I 1 L I 11 ' Sulluric Acid
.ssembly -\ \ _ ^ [' *j" ) Chemical fjj f Vhem ."«e"te"rin5>ump'«, *"'"[*"["?( T °?" " " " *" Storage Tank, „
Service
Water
Chlorine Cylinder
--
condary Chlorine Feed Syst
fChbrinato, Service Wa^erpj /
'-- > •, T L)Bl-J
I
CO
Chrfm'Lrs f™ "^ B""«i C°"''°' T"*li™ »""»' C°""°' S~>"d"» c'S' ™°^ MTtTw™"'"1
Chambers Screen cbrifier Box No , Fl|ler Box No j Oll,aa ^ ^ 3 chomb(,r "ln9 %e
~1 t I I t It i{s
Chemical Metering Pump
Polymer Feed Systerr
Chlorine Secondary Effluent
i.rvice WaterJ^, ^, ^..J,
I—li.»^.|tLj I
1 r-"?=r--fr'-?-r*
Backwash / package Lift
Digested Sludge to Sludge Thickener r~">— >— >-- >j r- -*
* "* "*
Sludge Gas to
Slud'ge'GoTSediment « D.ip Trap P'™<"V "j
d9e
^•f-T^-Tn-T- > —
ic. Watery ,Fj ^J i f Station
C i *- Cl«inoii) + To Drain
Thickened Sludge Pump Station Loodina Ar
APPENDIX B FIGURE B-2. WASTEWATER TREATMENT PLANT FLOW SCHEMATIC
-------
APPENDIX B
Water Budget Equation
' Q! + QB - (Q3 + Q8} - (Q5 + Q9 + Q12 + <*16 + V ' (Q14 + Q17 + V ~
CQ4 + Q7 + Qn) - (Q23 + Q24 - Q27 + Q31)
= Discharge to Lake - Metered and Recorded
QT = Influent to Tertiary Treatment Process - Metered and Recorded
QD = AWT Plant By-Pass - Not Metered
D
Q, + Q0 = 27,707 GPD Sludge Withdrawal from CU, + CIL (6-73 thru 3-74 average
JO 1 Z
nearly constant}
Q5 + Q9 + Q12 + Q16 + Q21 = 18'°39 Constant
Q-. + Qn_ + Q.0 = 24,376 GPD Constant
14 1/ 4o
Q + Q + Q = CU, + CU2 + SB Overflows rarely occur
Q23 + Q24 + Q2y + Q31 = 200 GPD Constant
= QT + QD - 27,707 - 18,039 - 24,376 + 200
1 B
= Qj + QB - 70,000
Q = Flow from City Collection System - Not Metered
Q = Secondary Effluent - Metered and Recorded
O
Q = Influent to Tertiary Treatment Process - Metered and Recorded
= Discharge to Shagawa Lake - Metered and Recorded
QD = AWT Plant By-Pass - Not Metered
B
QT = Influent to AWT Plant
Q = Pumped from Influent Tank to CU.
Q = Sample Flow (TCJ
Q = Sludge Withdrawal from O^
85
-------
Q4 = Overflow from CU
Q = Sample Flow (TCJ
b 2.
Q6 = Effluent from CU , Influent to CU
Q? = Overflow from CU2
Qg = Sludge Withdrawal from CU-
Q9 = Sample Flow (TS^
Q1Q = Effluent from CU2, Influent to SB
Qn = Overflow from SB
Q12 = Sample Flow (TS2)
Q13 = Effluent from SB, Influent to F
Q14 = Filter Backwash Water
Q15 = Effluent from F, Influent to VW
Q16 = Sample Flow (TVW)
0-_ = General Use Flow (like washing down floors)
Qlg = Special Use Flow (slaking lime, C02 feed, etc.)
Qig = Effluent from VW
Q2Q = Influent to PF
Q2 = Sample Flow (TP)
Q22 = Chemical Feed Prior to SB
^23 = Sulfuric Acid Feed
Q24 = Ferric Chloride Feed
Q25 = Chlorine Feed, Part of Q
Q26 = Water § Chemical Feed to CU
Q = Ferric Chloride Feed
86
-------
Q = Fiber Bearing Water
Q?q = Carbon Dioxide Feed
Q = Water § Chemical Feed to CU
Q = Pol/electrolyte (Uses City Service Water)
Q = Fiber Bearing Water
O ^
Q _ = Lime Feed
Q = Wastewater (Not Secondary) Influent to IF
O^
Q _ = Internal Plant Sewer - Showers, Toilets, etc.
oo
Q,fi = Seepage into Equalization Tank
Q__ = North Side Floor Drains
Q_0 = South Side Floor Drains
JO
^39 = Qll + <*14 + Q38 + ^36 + ^35
Q Q = Sludge Vacuum Filter Belt Wash Water
Q41 = Sludge Vacuum Filter Filtrate
Q42 = Sludge Thickener Overflow
Q43=Q40+Q41 +Q42
Q = Equalization Tank Contents Pumped to City Plant
Q = Stinky Ditch
Q._ = Drainage from Sludge Holding Pond
0.0 = Sludge Vacuum Filter Belt Wash Water
4o
^49 = <*14
Q50 = Sludge from Thickener (Use only when Sludge Vacuum Filter is down.)
Q = Solids to Sanitary Land Fill
87
-------
Q „ = Sludge from Thickener to Vacuum Filter
Q53 - Primary Sludge from City Plant to Sludge Thickener
Q 4 = Swamp, East Side of Plant (Receives Septic Tank Effluent)
88
-------
APPENDIX C
SECONDARY PLANT DATA
Month
Table C-l Primary Influent (mg/1)
Total Suspended Alkalinity
Phosphorus Solids as CaC03 B.O.D.
pH
July 1973
August
September
October
November
December
January 1974
February
March
7.08
4.47
4.14
4.05
11.01
9.09
9.00
7.72
276
297
74
68
357
177
203
162
181
187
137
148
235
204
186
172
136
66
60
39
80
113
120
109
7.54
8.18
7.36
7.66
8.24
8.25
8.12
7.89
Average
7.07
202
181
90
7.90
89
-------
Table C-2 Secondary Effluent (mg/1)
Total Suspended Alkalinity
Month Phosphorus Solids as CaC03 B.O.D. pH
July 1973 4.39 79 142 68
August 3.16 75 149 23.5 7.43
September 3.36 16 143 23.9 7.22
October 2.93 23 136 18.1 7.26
November 2.96 30 133 40 7.43
December — __
January 1974 4.33 58 142 7.44
February 4.78 33 135 46 7.30
March 4.57 42 130 56 7.22
Average 3.81 44 139 39 7.33
90
-------
Table C-3 Removal Through Trickling Filter Plant (%)
Month
July 1973
August
September
October
November
December
January 1974
February
March
Total
Phosphorus
46,0%
34
20
27
68
--
51
48
41
Suspended
Solids
72.0%
75
78
66
92
--
67
84
74
Alkalinity
as CaC03
22.0%
20
-7
8
43
--
30
27
24
B.O.D.
50,0%
64
60
53
50
--
--
62
49
Average 45.6% 76% 21% 55%
91
-------
APPENDIX D
YEARLY DATA SUMMARY - PLANT OPERATION AND PERFORMANCE *
Influent to Tertiary Plant
Parameters
Total Phosphorus Unfiltered
Total Phosphorus Filtered
Suspended Solids
Turbidity (JTU)
TOG
TIC
Calcium
Magnesium
Alk as CaC03
Iron
1973
April
3.62
2.42
37.0
25.0
29.9
39.8
6.3
144.0
May
3.61
2.30
46.0
31.4
28.5
47.8
8.62
153.0
June
4.96
3.34
60.1
16.7
40.4
53.9
8.3
154.0
July
5.22
2.74
105.0
30.3
39.8
56.8
7.2
156.0
August
4.66
2.30
100.0
22.8
35.8
53.4
7.5
161.0
September
3.83
1.93
71.0
25.0
47.4
6.7
159.0
All units mg/1 unless otherwise noted.
-------
Influent to Tertiary Plant (Continued)
Parameters
Total Phosphorus Unfiltered
Total Phosphorus Filtered
Suspended Solids
Turbidity (JTU)
TOG
TIC
Calcium
Magnesium
Alk as CaCOs
Iron
October
3.61
1.79
63.0
16.9
54.0
6.86
148.0
5.30
November
4.04
2.74
44.0
10.3
45.0
6.8
143.0
2.31
December
4.13
2.96
36.0
10.67
33.4
30.0
6.1
134.0
1974
January
4.44
3.03
41.0
11.4
34.7
27.2
34.7
5.6
137.0
1.93
February
6.59
3.49
122.0
34.51
62.87
35.63
27.0
5.4
147.0
3.12
March
5.98
3.10
110.0
41.47
53.25
27.93
5.65
138.0
3.84
Yearly
Average
4.56
2.68
70.3
23.0
39.9
31.4
43.2
6.75
148.0
3.3
(0
-------
First-Stage Lime Clarifier - Operation and Performance Data
Parameters
Flow (MGD)
Overflow rate (gpd/sq ft)
Lime (CaO)
Polymer (Betz 1150)
PH
Upper Mix Zone Solids Vol.
fml/1)
Lower Mix Zone Solids Vol.
fml/1)
Blanket (ft)
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Magnesium
Iron
Alk as CaCOs
1973
April
1.164
490
283.0
0.53
12.07
84.0
249.0
4.7
0.568
0.108
14.0
6.0
-
-
122.0
-
-
-
May
1.356
571.0
266.0
0.33
11.96
249.0
388.0
6.8
0.318
0.122
12.0
6.1
-
-
109.0
0.49
-
-
June
1.107
466.0
287.0
0.19
11.87
280.0
351.0
7.6
0.267
0.148
9.8
2.67
-
~
105.2 !
-
-
~ i
July
1.302
548.0
340.0
0.24
11.90
236.0
299.0
9.1
0.306
0.123
9.5
2.11
-
-
154.0
-
-
_
August
1.50
631.0
342.0
0.21
11.88
199.0
275.0
6.5
0.249
0.107
16.0
1.86
19.7
-
149.0
0.12
-
,_
September
1.33
560.0
343.0
0.20
11.90
147.0
191.0
4.9
0.269
0.093
8.0
1.89
_
-
153.0
0.14
-
^_
-------
First-Stage Lime Clarifier - Operation and Performance Data (Continued)
Parameters
Flow (MGD)
Overflow rate (gpd/sq ft)
Lime (CaO)
Polymer (Betz 1150)
pH
Upper Mix Zone Solids Vol.
(ml/1)
Lower Mix Zone Solids Vol.
(ml/1)
Blanket (ft)
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Magnesium
Iron
Alk as CaCO^
October
1.38
581.0
296.0
0.19
11.84
185.0
236
5.4
0.217
0.089
8.3
1.82
-
-
140
0.23
0.12
-
November
1.046
440.0
301.0
0.17
11.90
220.0
259
5.3
0.205
0.085
8.5
1.41
-
-
115
.1.2.7....
0.071
-
December
0.92
387.0
281.0
0.21
11.91
188.0
215
5.0
0.27
0.091
6.5
1.27
20.8
-
101
0.95
0.105
-
1974
January
0.85
358
274.0
0.19
11.95
134.0
151
4.6
0.347
0.094
7.0
1.53
19.3
3.72
94.2
0.6
0.92
-
February
0.82
345
282.0
0.21
12.03
253.0
283
5.5
0.284
0.127
7.0
2.41
21.57
4.31
98.6
0,2
0.089
1
March
0.88
371
271.0
0.23
12.03
289.0
332
6.22
0.279
0.126
9.0
2.17
29.46
-
101.05
0.25
0.119
-
Yearly
Average
1.14
479
297.0
0.24
11.94
205
269
6.0
0.298
0.109
9.6
2.60
22.2
4.01
120
0.47
0.099
-
-------
Second-Stage Lime Clarifier - Operation and Performance Data
VD
Parameters j
I April May
Flow (MGD) 1.164 ! 1.356
Recirculation (MGD) i 0.183 i 0.208
Overflow rate (gpd/sq ft)
C02 118 95
FeCl3 as Fe 5.60 6.07
PH 9.60 9.56
Solids Vol. (ml/1) UMZ 95 45
Solids Vol. (ml/1) LMZ | 106 i 5.5
Blanket (ft) 6 1.9
Total P - Unfiltered ~^ 0.171 ~*~ 0.110
_ _ . j ! i
Total P - Filtered 0.074 0.060
.. . . . i.. .
Suspended Solids 5 \ 6
Turbidity (JTU) 3.1 1 3.2
1UL 20.5 j 15.4
TIC - i _
Calcium 57.3 j 47.7
Iron - i
Alk as CaCO^ 89.4 j 74.2
i
June j
1.107 |
0.196 i
i
82 ;
5.57 :
9.56 !
40 |
46
2.9
0.097
0.024
8
2.53 ;
-
-
25.4
-
68,9
July
1.302
0.199
125
4.50
9.66
61
74
2.8 |
0.137 i
0.047 '
12 ;
2.40 i
i
:
40.9
-
72.7
j
August
1.50
0.199
131
5.79
9.64
31
41
2.8
0.070
0.020
11
T.88~"
-
-
46.6
-
55.8
!
i
! September
i 1.33
| 0.198
; 122
I 6.56
! 9.61
! 140
i 162
! 3.8
1 0.046
! 0.019
| 5
T "6" .'si
i
-
! 26.4
1 47.8
-------
Second-Stage Lime Clarifier - Operation and Performance Data (Continued)
Parameters
Flow (MGD)
Recirculation (MGD)
Overflow Rate (gpd/sq ft)
C02
FeCl3 as Fe
PH
Solids Vol. (ml/1) UMZ
Solids Vol. (ml/1) LMZ
Blanket (ft)
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Iron
Alk as CaCOs
October
1.38
0.174
108
5.87
9.60
146
173
4.0
0.034
0.018
6
0.94
! ~
27.8
-
i —
November
1.05
0.159
98
6.07
9.60
140
160
3.4
0.056
0.031
7 '
1.63
-
-
23.1
0.44
. .
-
December
0.92
0.166
79
5.79
9.59
180
194
4.3
0.046
0.024
4
1.28
19.0
7.04
27.4
0.43
_ —
-
1974
January
0.85
0.164
81
5.88
9.55
148
160
3.9
0.060
0.031
3.5
0.99
14.6
10.0
34.7
0.544
| •- "
-
February
0.82
0.160
82
7.13
9.62
160
177
4.0
0.060
0.027
7
1.38
15.7
12.68
36.0
0.590
—
-
March
0.88
0.166
80
7.19
9.65
99
113
3.3
0.105
0.017
11
3.38
24.58
-
36.7
0.717
-
Yearly
Average
1.14
0.181
556
100
6.0
9.60
107
122
3.6
0.083
0.033
7.1
1.96
18.3
9.9
35.8
0.544
68
-------
Hravity Filter Influent Data
00
Parameters
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Magnesium
Alk as CaC03
Iron
Total Solids
Temperature (°C)
FeCl3 as Fe+3 (dosage)1
Cl2 (dosage)
1973
April
0.171
0.074
5
3.1
-
-
57.3
0.&5
-
-
303
-
0
1.92
1 !
May | June
0.115 ' 0.098
0.022 j 0.043
15 j 7
5.9 ! 2.4
1
i
39.3 i 28.0
0.59 ;
57.0 i 40.0
I
224 i
! 13.0
2.38 i 2.12
3.08 I 2.98
July
0.142
0.073
8
1.53
_
-
36.6
-
43.4
-
15.1
2.20
3.80
August
0.073
0.039
7
1.21
_
_
42.8
-
40.4
-
15.4
2.24
4.84
September
0.043
0.016
7
1.30
.
27.0
-
24.0
-
16.2
2.42
3.65
(1) Starting May 10, 1973
-------
Gravity Filter Influent Data (Continued)
Parameters
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Magnesium
Alk as CaCO?
O
Iron
Total Solids
Temperature °C
FeCl3 as Fe+3 (dosage)
C12 (dosage)
October
0.046
0.019
6
1.48
-
-
38.0
-
20.5
3.15
239
14.8
2.32
2.79
November
0.054
0.027
7
1.45
-
-
25.0
-
22.8
2.98
176
11.7
2.88
2.85
December
0.045
0.017
8.7
1.83
18.8
5.9
29.7
-
33.5
3.40
154
9.6
3.23
2.62
1974
January
0.061
0.021
9
1.43
17.5
9.1
36.2
-
49.9
3.47
205
8.82
3.24
2.34
February
0.081
0.036
10
2.19
16.08
10.37
41.09
-
42.7
3.23
274
8.66
3.41
2.40
March
0.144
0.065
14
2.8
25.53
-
52.5
-
44.8
4.24
-
7.68
5.51
3.17
Yearly
Average
0.089
0.038
8.6
2.22
19.5
8.5
37.8
0.62
38.1
2.25
225
12.10
2.66
3.04
-------
Tertiary Plant Effluent Data
Parameters
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOG
TIC
Calcium
Magnesium
Alk as CaC03
Iron
BOD
Total Coliform (No./lOO ml)
Fecal Coliform (No./lOO ml)
r\ r*
u . w .
Residual Chlorine
PH
1973
April
0.070
0.058
2
2.6
19.9
-
65.7
0.58
90.4
-
-
-
-
_
0.46
7.67
May
0.060
0.046
1
1.2
18.4
-
49.7
0.57
59.6
_
-
-
_
_
0.52
7.55
June
0.046
0.033
0.76
0.45
16.0
_
28.7
0.3
38.7
_
23.8
0
0
9.1
0.55
7.42
July
0.076
0.062
1.6
0.17
12.1
_
36.6
0.2
42.2
_
10.3
0
0
9.3
0.45
7.53
August
0.041
0.038
1
0.11
8.9
_
37.6
0.3
32.4
_
-
0
0
9.3
0.41
7.50
September
0.022
0.016
1
0.33
.
27.4
0.11
23.9
_
0
0
8.9
0.51
7.51
o
o
-------
Tertiary Plant Effluent Data (Continued)
Parameters
Total P - Unfiltered
Total P - Filtered
Suspended Solids
Turbidity (JTU)
TOC
TIC
Calcium
Magnesium
Alk as CaC03
Iron
BOD
Total Coliform (No./ 100 ml)
Fecal Coliform (No./lOO ml)
D.O.
Residual Chlorine
PH
October
0.023
0.017
1.7
0.44
-
-
40.4
0.15
22.3
0.20
-
0.6
0.16
9.25
0.51
7.45
November
0.032
0.029
1.0
0.33
-
-
24.8
1.27
22.1
1
0.21
-
0
0
10.04
0.25
7.53
December
0.021
0.017
1.4
0.32
16.7
5.88
27.4
0.43
33.7
0.17
-
0.1
0
10.3
0.17
7.54
1974
January
0.026
0.022
1.0
0.14
15.0
-
36.3
0.56
49.9
0.176
3.78
0.3
0
10.6
0.14
7.50
i
February
0.043
0.036
1.5
0.20
16.2
9.98
41.53
0.3
42.7
0.175
11.27
0
0
10.83
0.16
7.40
March
0.077
0.065
2
0.43
23.75
-
53.51
0.28
44.8
o . 3 do"1
-
0
0
11.4
r~ 0.18
7.47
Yearly
Average
0.045
.037
1.3
0.56
16.3
7.9
39.1
.42
41.9
0.21
12.3
0.10
0.02
9.9
0.36
7.50
-------
APPENDIX E
TOTAL PHOSPHORUS DATA: APRIL, 1973 THRU MARCH, 1974
102
-------
O)
E
Of
O
I
o.
O
X
<
o
TERTIARY PLANT
INFLUENT TOTAL P
(FIRST STAGE INFLUENT)
FIRST STAGE EFFLUENT
TOTAL P
SECOND STAGE
EFFLUENT TOTAL P
' I I I I I I I
5 15 25 5 15 25 5 15 25
AUG. SEPT. OCT.
5 15 25 5 15 25
JUNE JULY
5 15 25 5 15 25
APR. MAY
APPENDIX E, FIGURE E-l. DAILY TOTAL P CONCENTRATION FROM APRIL 1, 1973 TO MARCH 31, 1974 (mg/l).
-------
Table E-l
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
April
1973
1
2
3
4
5
6
7
8
9
10
11
!2
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
V
SEC.
EFFL.
4.74
3,20
3.79
6.26
4.18
4.35
4.24
4 71
3.99
3.61
4.45
4.56
4.09
3.57
3.67
4.09
4.40
4.03
3 81
—3,17
4.06
5.11
4.188
0.6323
15.1
1st STAGE
CLAR.
INF.
3.42
3.89
* HQ
3.57
V4Q
2.92
3.31
3.07
4.43
3.73
3.78
4.04
\ <;?
3.63
\ ^Q
3.34
3.64
3.70
3.46
3. 49
3.14
2.80
3.20
4.02
5.25
3.81
3 6J1
4.07
2.83
4.54
3.622
0.5149
14.2
1st STAGE
CLAR.
EFFL.
0.582
0.439
n c;^
0.729
n.s.vi
0.540
n.Qfl3
0.902
0.943
0.717
0.674
0.641
0 68.8
0.514
0.488
0.586
0.627
0.579
0.629
0.935
0.665
0.494
0.454
0.280
0.331
0.259
0.295
0.413
0.371
0.294
0.5682
0.1938
34.1
2nd STAGE
CLAR.
EFFL.
0.122
0.111
n 177
0,155
n.?.?4
0.249
°-26Z
0.238
0.205
0.232
0.191
0,190
n ?ns
0.21.7
0.184
0.159
0.201
0.197
0.208
0.179
0.186
0.169
0.138
0.126
0.101
0.100
n inn
0.101
0.143
o.n:
0.1713
0.0494
28.9
D.M.
FILTER
EFFL.
0.030
0.022
n n?s
0.032
n.nsn
0.026
0.032
0.035
0.024
0.039
0.078
0.072
n n?Q
0.091
0.073
0.080
0.100
0.101
0.107
0.091
0.105
0.101
0.101
0.089
0.078
0.079
n n?s
0 078
0.114
0.094
0.0695
0.0305
43.9
EFFL.
TO LAKE
0.032
n.nss
0.038
n.n*q
0.0.35
0 . 036
0.035
0.039
0.043
0.065
0.074
n n?^
0.077
0.070
0.080
0.096
0.104
0.102
0.085
0.114
0.090
0.083
0.079
0.073
0.068
n n^t;
n nvs
0.100
0.094
0.0690
0.0251
6.4
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
83.0
88.7
8^.1
79.6
84.6
81.5
72.7
70.6
78.7
80.8
80.2
84.1
sns
85.8
85.6
82.5
82.8
84.4
81.8
73.2
78.8
82.4
85.8
93.0
93.7
93.2
ai a
SQ Q
86.9
93.5
83.84
5 . 988
7.14
2nd STAG
LIME
CLAR.
79.0'
74.7
7fiT ^
78.7
58.4
53.9
7Q-4
73.6
78.3
67.6
71.7
70.4
fiq.8
57.8
62.3
72.9
67.9
66.0
66.9
80.9
72.0
65.8
69.6
55.0
69.5
61.4
f.f. ^
7^L ^
61.5
62.2
68.54
7.201
10.5
DUAL-
MEDIA
FILTER
75.4
80.2
78 n
79.4
86.6
89.6
80.0
§5.3
88.3
83.2
59.2
62.1
6? n
58.1
60.3
49.7
50.2
48.7
48.6
49.2
43.5
40.2
26.8
29.4
22.8
21.0
oo n
77 R
20.3
15.3
54.61
24.24
44.4
TERTIARY
PLANT
99.1
99.4
qq ?
99.1
99.1
99.1
99.0
98.9
99.5
99.0
97.9
98 2
Q7 R
97.5
97 g
97.6
97.3
97 3
96.9
97.4
96.7
96.4
97.4
98.0
98.6
98.2
OT Q
qs 1
96.0
97.9
98.07
0.9340
0.952
SEC. PLUS
TERT.
PLANT
EPA-280 (Cin)
(12-75)
-------
Table E-l ("continued")
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
May
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
V
SEC.
EFFL.
4 74
3.70
34^
_2 29
7 45
2.77
2.22
2 81
3 m
7 99
3 ^8
^ ^2
3 55
4.04
4 68
3 30
3.74
2.78
7 qi
3.32
3.43
4 74
3 q4
3 60
3.384
0 7069
20.9
1st STAGE
CLAR.
!NF.
4.74
3.64
3 70
3.49
3 3q
7.88
3 70
7 63
2.91
2.85
3 42
7 95
3 78
3 49
3 30
353
3 85
3.52
4.04
3 66
5 76
4.63
.3.. 37
4 81
3.06
3.28
.3.. 3 5
4 17
4 qq
4 1 1
3 7°
3.655
0 6635
18.2
1st STAGE
CLAR.
EFFL.
0.307
0.280
n 5^0
0.557
n 572
0.500
0.295
0 384
0.352
0.208
0 230
0 760
0 777
0 2c;2
0 307
0 276
o 798
0.288
o 298
0.274
0 781
0.298
0.301
0 346
0.367
0.277
o.2oq
0 21Q
0.253
0.25.3
n 3Qq
0.3178
0.9650
.30.4
2nd STAGE
CLAR.
EFFL.
0.129
0.094
0 102
0.175
n 14D
0.147
0.101
0 1 oq
0.105
0.080
0 093
0 108
0 114
0 114
0 143
0 130
0 1 70
0.112
0.122
0.115
0111
0.125
0.130
0 162
0.152
0.125
0.094
n n«o
0.086
0.091
n ins
0.1151
0.0207
18.0
D.M.
FILTER
EFFL.
0.108
0.072
0.053
0.058
n 076
0.079
0.053
0 046
0.073
0.053
0 051
0 051
O.053
n n5i
n 065
n 064
0 050
0.061
0.065
0.068
0.058
0.065
0.064
0.086
0.073
0.065
0.047
0 036
O.033
0.0.39
n 047
0.0601
0.0154
25.6
EFFL.
TO LAKE
0.103
0.059
0.049
0 . 048
0 067
0.196
0 091
0.089
0.059
0.062
0 059
0.049
o 049
0 053
0 043
0 . 043
0.051
0.057
0.051
0.048
0.048
0.052
0.070
0.057
0.058
0.050
0 040
0 . 0.38
0 . 0.36
o 044
n.0605
0.0298
49.2
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
93.5
97.3
85.7
84 0
8^ 1
87 6
90.8
85 4
87.9
92.7
9.3.3
91 .7
91 .6
97 8
90 8
97 7
97.3
91.8
92.6
92.5
94.7
93.6
91.1
92.8
88.0
91.6
93.8
94 7
95.0
9.3.8
91 8
90.97
3.457
3.8
2nd STAGE
LIME
CLAR.
58.0
66.4
80.8
77.6
75 5
70 6
65.8
71 6
70.2
61.5
59.6
58.5
58.8
54 8
52.6
57 9
59.7
61.1
59.1
58.0
60.5
58.1
56.8
53.2
58.6
54.9
55.0
63 5
66.0
64.0
65 0
62.22
7.319
11.76
DUAL-
MEDIA
FILTER
16.3
73 4
48.0
53.6
45 7
46 3
47.5
57 8
30.5
33.8
45.2
52.8
5.3.5
55 3
54.5
50 8
58.3
45.5
46.7
40.9
47.7
48.0
50.8
46.9
52.0
48.0
50.0
55 . 0
61.6
57.1
56 . 5
47.74
9.998
20.9
TERTIARY
PLANT
97.7
98 0
85.7
98 3
Q7 8
97 3
98.3
98 3
97.5
98.1
98.5
98.3
98.4
98 5
98.0
98.7
98.7
98.3
98.4
98.1
98.9
98.6
98.1
98.2
97.6
98.0
98.6
99.1
99.3
99.1
98.8
9?.89
2.310
2.4
SEC. PLUS
TERT.
PLANT
O
tn
EPA-280 (Cin)
(12-75)
-------
o
ON
Tabl
DATE
June
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
•»T
28
29
30
MEAN
STDDE
%CV
e E-l f continued! TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
V
SEC.
EFFL.
4 78
3.64
5 IS
4 53
4.532
n 6^94
iM
1st STAGE
CLAR.
INF.
4.10
4 63
4.10
•; 33
4.71
4.29
4.57
A 4R
6.714
4.65
5.72
s 69
4.93
4.50
4 7Q
4.5?
3 7n
5.65
5.fifi
5 32
A 89
4 49
5.11
4 QQ
4 97
4 20
r- r\ y
n -111
6.08
5.17
5.06
4.955
0,6401
12.92
1st STAGE
CLAR.
EFFL.
0.331
0.996
0.341
0.269
0.273
0.280
0.260
n 7*9
0,285
0.260
0.288
n 999
0.278
0.269
n 963
0.306
0.22Q
0.237
0 . 245
0 2°1
n 749
n 979
0.238
JL_224_
n 75Q
n 278
f\ r\ TV
11. ^.T.T
n 238
0.249.
n 963
_Q.2669
n n796
11.10
2nd STAGE
CLAR.
EFFL.
0.109
0.125
0.127
0.122
n 136
0.133
0.114
n DQ7
n r>Q4
n n«Q
0.086
n in7
0.118
0.094
o.nsq
0.109
0.083
0.083
0.100
n nan
n 089
0.084
0.093
0 . 083
n nsq
n ns4
u. u/»
n n7*
0.082
n nQ4
0.0982
0.0176
17.9
D.M,
FILTER
EFFL.
0.044
0.048
0.048
O.OS9
n nss
0.060
0.050
n .05.^
n n4fi
n n^o
0.043
0.048
0.050
0.048
0.046
0.050
0.043
0.033
0.050
n n3<;
0.044
0.039
0.060
0.062
0.053
n.fUR
U.UJ3
n n49
0.037
n n38
0.0464
0.0075
16.2
EFFL.
TO LAKE
0.041
0.041
0.037
0.049
n n^3
0.052
0.052
n n47
n n3s
n n3<;
0.040
0.043
0.053
0.042
0.028
0.045
0.032
0.053
0.050
n n4n
0.040
0.043
0.047
0.063
0.05.3
O.n47
U. UH-3
n n3Q
0.036
0.037
0.044
0.0076
17.4
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
91.9
93.6
91.7
95.0
94 9
93.5
94.3
94.1
95.5
94 4
95.0
94.7
94.4
94.0
94.5
93.2
93.8
95.8
95.7
94 ^
94.9
95.1
95.3
95.5
94.8
93.5
| 96.1
96.1
95.3
94.8
94.51
1.065
1.13
2nd STAGE
LIME
CLAR.
67.1
57.8
62.8
54.6
50.2
52.5
56.2
63.0
67.0
65.8
70.1
64.2
57.6
65.1
66.2
64.4
63.8
65.0
59.2
72.5
64.3
62.2
60.9
62.9
65.6
69.8
f f i
UU . J.
69.3
66.1
64.3
63.22
5.20
8.23
DUAL-
MEDIA
FILTER
59.6
61.6
62.2
68.0
57.4
54.9
56.1
45.4
51 .1
56.2
50.0
55.1
57.6
48.9
48.3
54.1
48.2
60.2
50.0
56.3
50.6
53.6
35.5
25.3
40.4
42.9
i- r\ f
^\J . U
42.5
54.9
59.6
51.90
'8.65
16.66
TERTIARY
PLANT
98.9
99.0
98.8
99.3
98.8
98.6
98.9
98.8
99.3
99.2
99.2
99.2
99.0
98.9
99.0
98.9
98.8
99.4
99.1
99.3
99.1
99.1
98.8
98.8
98.9
98.9
r\r\ *r
yy . j
99.3
99.3
99 2
99.04
0.2125
0.21
SEC. PLUS
TERT.
PLANT
, *
EPA-280 (Cm)
(t2-75)
-------
Table E-l (continued)
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
July
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
5.93
7 63
11.5
5.53
11.0
5.11
3.82
6 16
7.085
V 2.785
39.3
SEC.
EFFL.
5 66
4.14
4.83
5 18
4.40
5 . 35
3.27
7 7Q
4.390
1.139
25.9
1st STAGE
CLAR.
INF.
4,54
5.87
5 80
5.60
5.29
3. 60
8.37
4.40
6.66
5 48
5.93
2.08
/I /|5
4 43
6.40
7 83
5.42
4 83
4.79
4 61
6.65
6.40
4.82
4.43
5.07
^ 66
4.00
7 1Q
6 69
3.74
7 81
5.221
1.408
26.97
1st STAGE
CLAR.
EFFL.
0,765
0.319
n ^2^
0.255
0.229
0 229
0.291
n 777
0.288
n ^07
0.295
0 . 256
0 345
0715
0.229
n ?7n
0.447
0 878
0.463
0 767
0.255
0.216
0.235
0.525
0.317
o ^71
0.274
n i T\
0 180
0.195
n 201
0.3059
0.1337
43.7
2nd STAGE
CLAR.
EFFL.
0, 177
0.120
0.105
0.102
0.103
0 124
0.149
0 147
0.337
0 V*
0.289
0.219
0 119
0 1 51
0.1.31
0 1 37
0.166
0 1QQ
0.176
0118
0.078
0.065
0.101
0.142
0.252
0 1 ?q
0.090
0 nc;4
0 044
0.042
0 047
0.1420
0.076K
53.6
D.M,
FILTER
EFFL.
0.044
0.05.3
0.057
0.053
0.051
0 Ofi5
0.093
0 075
0 1.38
o 104
0.118
0.118
0 097
o 105
O.OQ1
0 083
0.127
0 1 37
0.104
0 06q
0.044
0.043
0.063
0.089
0.100
o 074
0.053
o o^q
0 021
0.025
0,074
0.0757
0.0333
44.0
EFFL.
TO LAKE
0.043
0.044
0.057
0.032
0.051
0 065
0.093
0 075
0 138
o 104
0.123
0.118
0 0Q7
0105
0.091
0 08^
0. 127
0 1 ^7
0.104
0 06q
0.044
0.043
0.063
0.089
0.100
0 660
0.114
n 0^6
o 025
0.024
0,074
0.1125
0.1958
174.0
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
94.2
94.6
90.9
95.4
95.7
q^ 6
96.5
95 0
95.7
Q4 S
95.0
87.7
Q9 7
q5 i
96 4
Q6 6
91 .8
87 q
90.3
q4 7
96.2
96.6
95.1
88.1
93.7
8q q
93.2
q7 6
qy \
94.8
97.8
93.66
3.227
3.44
2nd STAGE
LIME
CLAR.
54.0
67 . 4
80.0
60.0
55.0
45 q
48.8
33 8
17 0
6 q
2.0
14.4
56 8
79 8
42.8
m 1
62.9
76 0
62.0
^ s
69.4
69.9
57.0
72.9
20.5
65 7
67.2
68 8
7^ f>
78.5
79.1
51.41
25.59
49.78
DUAL-
MEDIA
FILTER
63.9
55.8.
45.7
48.0
50.5
47 6
37.6
49 0
5q 0
67 8
59.2
46. 1
34 9
30 5
30 . 5
37 1
23.5
33 7
40.9
41 q
43.6
33.8
37.6
37.3
60.3
4? 6
41.1
35 2
57 ^
40.5
42.9
44.19
10.59
23.96
TERTIARY
PLANT
99.0
qq 1
99.0
99.0
99.0
q« 2
98.9
q8 ^
q? q
q» i
98.0
Q4..3
97.8
q? 6
98.6
qs q
97.7
97 .3
97.8
q8 5
99.3
99.3
98.7
98.0
98.0
98 0
98.7
99 5
qq 7
99.3
qq.i
98.41
0.9896
1.01
SEC. PLUS
TERT.
PLANT
98.9
98.6
99.0
97.7
98.8
98.3
97.4
98.8
98.44
0.593
0.60
EPA-280 (Cin)
(12-75)
-------
Table E-l fcontinuedl
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Aug.
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
IX
^ w
27
28
29
30
31
MEAN
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
4 HO
4 c;6
2 Q4
1.20
q.74
4.96
3.89
4.47
STDDEV 7 633^
%CV 1 58.91
SEC.
EFFL.
2 7^
3 in
3.31
3 Q2
3.17
.3.16
3.70
3,07
3.1575
0.775.3
8 7?
1st STAGE
CLAR.
!NF.
^ ^2
4.18
6 Ql
4.99
c; 33
3.50
4 4^
9 qi
7 74
3 14
2 6q
3,99
4 71
3 %
3.91
q 07
5.30
7,98
5 71
6.23
4.02
4 87
4.97
4.85
3 . QQ
5 11
5,51
5 . 75
5, IS
3.82
4,658
1.37.3 i
9Q 48
1st STAGE
CLAR.
EFFL.
n 211
0.214
0 211
0.241
0 24-0
n,7n<;
0.493
i no
(1,168
0 154
0.190
n 163
0,158
0 21^
0 471
0.191
n 184
n 713
0.190
n 187
0.216
0.208
0.186
0.205
0.705
n , ? 1 5
0 240
0.242
0.249
0 738
0.209
0.2488
0.1576
63 34
2nd STAGE
CLAR.
EFFL.
n 047
0.066
0 048
0.053
n 104
n.iin
0.115
n ]8Q
n. 178
0 110
0.093
n n78
0.1.37
n 083
n n67
0.044
n n.50
n o<;7
0.046
n 040
0.046
0.045
n 043
0.048
n.05i
u. iio.^
n Q^(f
0.060
0.051
n 047
0.046
0.0726
0.0393
^4 16
D.M.
FILTER
EFFL.
n 074
0.029
o 02°!
0.031
0 068
0.076
0.093
0 OQ6
0.068
0 0^8
0.054
0 068
0.048
0 O^R
n 044
0.030
0.029
0 07Q
0.024
0 074
0.025
0.026
0 073
0.030
0.032
u . ii.-ju
o 0^4
0.035
0.029
0.021
0 09/1
0.0415
0.0213
51.25
EFFL.
TO LAKE
0 02^
0.027
0 028
0.0.37
o 074
0.080
0.135
0.6^7
0.777
0 06Q
0.066
0 060
0.057
o ns<^
o 049
0.025
0.031
0 037
0.024
0 07Q
0.033
0.027
0.07.3
0.029
0.032
u. u.iz.
0 036
0.036
0.027
0.028
0 048
0.0699
0.1157
165.41
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
Q6 2
94.9
Q6 Q
95.2
qc; q
94.1
88.9
65 6
97.5
qc; i
99.5
93 9
96.0
qq 4
88 1
95.1
98.0
96.0
93.6
96 7
96.5
94.8
96.1
95.9
95.8
r\ A *-•
i«+. 0
qc; 3
95.6
95.7
95.4
Q4 5
93.14
7.117
8.285
2nd STAGE
LIME
CLAR.
77 7
69.2
77 2
78.0
56 7
46.3
76.7
81 .1
6.0
78 6
51.0
52.1
13.3
61 4
85 8
77.0
72.8
75.6
75.8
78 6
78.7
78.4
76.9
76.6
75.1
77. 2
76 7
75.2
79.5
80.2
78 0
67.14
21.119
31.46
DUAL-
MEDIA
FILTER
48 q
56.1
3q 6
41.5
34 6
30.9
19.1
49 2
61 .8
47 3
41.9
12.8
65.0
33.7
34 3
31.8
42.0
44.2
47.8
40 0
45.6
42.2
46.5
37.5
37.2
*7 ri o
00. 0
39 3
41.7
43.1
55.3
47 »
41.85
10.63
25.40
TERTIARY
PLANT
99 6
99.3
qq 6
99.4
98 7
97.8
97.9
96.7
97.0
98 7
98.0
97.5
98.8
98.8
98.9
99.2
99.7
99.4
99.2
99.6
99.6
99.3
99.5
99.4
99.3
r\r\ 'i
yy . £
99 3
99.4
99.5
99.6
qq,4
98.93
0.8149
0.8237
SEC. PLUS
TERT.
PLANT
98 3
98.3
98 1
99.7
99.4
99.5
98.88
0.722
0.730
o
00
EPA-280 (Cin)
(12-75)
-------
o
Tab e E-l f continued} TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Sept
1973
I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
MEAN
STD DEI
%CV
RAW
WASTE
3.85
.3.6,3
4.43
3. fin
3 71
3.73
5 71
4,18
4.40
5.50
3 96
3.71
3.85
5.60
4 in
3 16
4.35
3.60
4.143
/0.68027
16.42
TOTAL PHOSPHORUS GONTRATION - mg/l
SEC.
EFFL.
3.02
4.20
7.63
2.83
3.14
2.73
4,18
3.1?
3.32
3.32
7 80
3.n.3
3.13
4.n2
3 03
7.20
1.41
3.359
1.1827
3.5.2
1st STAGE
CLAR.
INF.
2.71
2.08
2 . 35
3.05
2.1Q
2.87
3.01
3.21
4.35
3.79
4. on
1 10
4,83
3.67
4.45
3.84
5.11
4,43
5.66
5.17
3 75
3.05
3.32
3 92
3.46
4 85
4.38
6.76
4.35
3.74
3.8347
1.0603
27.65
1st STAGE
CLAR.
EFFL.
n 7nq
0.134
0.166
0.205
n.247
0.306
0.467
n.4no
0.280
o.soi
n 37i
n 738
n 3QQ
0.341
0.288
0.262
n 76Q
n pss
0.269
0.307
n.33n
0.27.3
0.254
0.259
0 753
n ?3n
0 22°
0.217
0.230
n 2^6
0.2694
0.0655
24.31
2nd STAGE
CLAR.
EFFL.
0.038
0.027
0.023
0.062
n.033
0.043
0.083
0.111
0.057
0 045
n n47
0 034
n n35
0.0.39
n.n.37
0.034
n 033
n n3«
0.037
0.042
0.054
0.047
n 04n
0.037
n.04i
n 035
0 035
0.035
0.040
n n35
0.0431
0.01708
39.63
D.M.
FILTER
EFFL.
n.n77
0.016
0.014
0.036
0 018
0.022
0.03.3
0.056
0.023
0.093
0.020
0 017
n n2l
n.019
0.017
0.016
n ni4
n nio
0.017
0.022
0 037
0.025
0.025
0.019
n 07n
n,ni7
0 018
0.019
0.020
n nio
0.0220
0.00827
37.59
EFFL.
TO LAKE
0 . 554
0.382
0.109
0.070
0.078
n.n66
n.nsn
0.0.36
0.025
O.n?9
0.076
n n20
n n?n
0.021
0 .021
0.018
O.OIQ
n 077
0.022
0.028
0.031
0.024
0.024
0.025
0.024
n n?n
0 nlQ
0.020
0.020
n mo
0.0614
0.1148
186.97 II
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
97 79
93.56
92.94
93.28
88 Q5
89 34
84.48
87.54
93.56
98.81
91 .98
97 . 54
93,6n
90.71
9.3.. 5.3
93.18
94 74
Q3 5n
95.25
94.06
89 85
91.05
92.35
9.3.39
I 92.69
[ 95 76
04 77
96.79
94.71
04 40
92.77
2.782
2.999
2nd STAGE
LIME
CLAR.
SI 87
79.85
86.14
69.76
86 36
85 95
82 23
72 25
79.64
8.5 . 05
86.97
85 71
88 67
88.56
8715
87.02
87 73
86 81
86.24
86.32
8.3 . 64
82 78
84.25
85.71
83 79
84 7R
84 72
83 87
82.61
83 01
83.98
4.210
5.013
DUAL-
MEDIA
FILTER
47 in
40.74
39.13
41.94
45 45
48.84
60.24
49 . 54
59.65
48 89
52 38
50 . QQ_
40 00
51 28
54.05
52.94
57 58
50 on
54.05
47.62
40.74
46.81
37.50
48.65
51 22
.51 .43
4g 57
45.71
50.00
45 71
48.76
5.662
11.61
TERTIARY
PLANT
QQ 1Q
99.23
99.40
98 82
99 1 8
99 23
98.90
98 26
99 47
99 . 39
99. 5n
99.47
Q9.56
99 48
99.62
99.58
99.7.3
9Q 57
99.70
99.57
99.02
, 99.18
99.25
99.52
99.42
99 65
gq cq
99.72
99 54
J)9 49
99.07
1.759
1.776
SEC. PLUS
TERT
PLANT
99.4
99. i
qq 5
99.5
99 5
99.6
99. 7
qq c;
99.6
99 6
99.2
i 99.5
99.4
99 7
99.5
99 5
99.6
99 4
99 48
0.159
0.160
EPA-280 (Cin)
(12-75)
-------
Tahi* F.I OnntiTiiiPcn TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Oct.
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
•>A
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
^ ^4
4 82
A qq
4.31
A 3q
5 14
3 86
5 IT
1 7fl
1 Q7
2.49
1 28
3 06
3 25
^ 64
2 72
3 00
•z of.
2 q6
3.18
3.24
5.28
4.86
5 46
13 2
3,73
3 61
4.050
V 9 230
cc DA
SEC.
EFFL.
3 74
3 88
3 07
3.61
3 38
3. 7.3
2 68
3.22
1 68
1.46
1 .26
1 9^
2.14 -
1 C7
2. 18
2 4q
•7/17
2 =;n
2.86
5.27
3.31
2 63
2 72
2.77
•Z -7/1
.3.16
3.81
3 78
2.6n
3 29
2.9.31
0,8448
2» §2
1st STAGE
CLAR.
INF.
5,10
5.25
4 on
5.06
1 7^
4.68
4 4<;
5.25
3.17
2 2Q
2.49
1 .90
2 08
2.45
3 42
.3.10
4 OQ
-7 88
3 ^4
3 22
2.65
3.46
2.93
3 !"*•
.3 . .32
A T7
3.91
3 81
4 ^
3.78
3.46
3.614
0 9489
2« 7£>
1st STAGE
CLAR.
EFFL.
n , 234
0.241
n 222
0.219
n IP?
0 . 5.30
0,1 q>;
n iq3
n 2Q6
0,224
0.211
0.202
0 188
0.218
0 222
0.179
n 17=;
0 207
n 181
0.174
0.177
0.190
n 1Q3
n 185
0.220
n i 77
0.234
n 195
0 1QQ
0.211
0.246
0.2171
n. 06.37
9Q ^4
2nd STAGE
CLAR.
EFFL.
n n^4
0.038
n 0^4
0.032
0 028
0.027
n.n.3n
n.028
n 07i
n 04^
0.034
0 . 0.3.3
0 028
0.029
0.0.32
0.029
n n^o
0 028
0 031
0.029
0.028
0.029
0.029
0 028
0.031
n n*i
0.036
0.0.39
0 187
0.202
0.1.32
0.0464
0.4411
Qt; 06
D.M.
FILTER
EFFL.
0 01Q
0.024
0,021
0.018
0,014
0.014
0 01 R
0.014
0.052
0 031
0.024
0.023
0 01Q
0.017
0.018
0.020
0 01Q
0 016
0 016
0.018
0.016
0.016
0.017
0 01Q
0.017
n m «
0.017
0.021
0.036
0.069
0.047
0.0227
0.012.3-
c;4 40
EFFL.
TO LAKE
0 022
0.027
n 024
0.020
0 017
0.015
0 017
0.112
0 790
0.851
1.20
0.632
0 "4
0.049
0.060
0.028
n o?4
0 023
0.02.3
0.022
0.019
0.019
0.018
0 018
0.019
n m s
0.019
0.027
n n^4
0.049
0.06.3
0.1488
0.2972
199 7.3
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
95.4
95.4
QH 5
95.7
Q4 8
88.7
Qi; 6
96.3
90.7
Q0.2
91.5
89.4
91.0
91.1
9.3.5
94.2
0=; 7
«2 8
94. 9
94.6
93.3
94.5
9.3.4
Q4 1
93.4
Q"; s
94.0
94.9
qq 4
94.4
92.9
93.65
2 . 054
2. 19.3
2nd STAGE
LIME
CLAR.
85 . 5
84.2
84 7
85.4
85 . 5
94.9
84.6
85.5
76.0
80.8
83.9
83.7
85 1
86.7
85.6
8.3.8
82 Q
«A t;
82.9
83.3
84.2
84.7
85.0
84.9
85.9
82 5
84.6
80.0
6.0
4.3
46.3
78.06
20.826
26.68
DUAL-
MEDIA
FILTER
44.1
36.8
38 2
43.8
qo o
48.1
50.0
50.0
26.8
27.9
29.4
30.3
32 1
41.4
43.8
31.0
36.7
49 q
48.4
37.9
42.9
44.8
41.4
32.1
45.2
41 .9
52.8
46.2
80.7
65.8
64.4
43.48
11,637
26.76
TERTIARY
PLANT
99.6
99.5
qq 6
99.6
99 6
99.7
qq 7
99.7
98.4
98.6
99.0
98.8
qq 1
99.3
99.5
99.4
99 . 5
qq 4
99.5
99.4
99.4
99.5
99.4
99.4
99.5
99.6
99.6
99.4
99.2
98.2
98.6
99.31
0.3964
0.3992
SEC. PLUS
TERT.
PLANT
99.7
99.5
qq 6
99.6
9q.7
99.7
qq.6
99.7
—
98.4
99.0
98.2
99 4
99.5
99.3
99.3
qq.4
qq <;
99.5
99.4
99.5
99.7
99.7
99.6
99.7
98.2
98.7
99.35
0.462
0.465
EPA-280 (Cin)
(12-75)
-------
Table E-l (continued)
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Nov.
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
3.85
4 30
3 . 54
5 fiQ
11.1
16 5
26.0
13.7
4.18
8.06
6.37
6.84
10.0
5.97
71 7
10 7
?T n
5.86
15.1
Q Ofi
4 S1^
21 .9
Q 96
is. n
11 010
v 6 6949
fiO 807
SEC.
EFFL.
2.39
7 97
3.67
3.48
4.04
2 °>4
2.91
2.67
3.35
4,]8
1.98
3.17
7 04
2 34
7 33
2.964
n 6879
33,209
1st STAGE
CLAR.
INF.
3.22
3 64
3 . 95
3 86
4.49
3 8fi
3.88
3.91
3.77
4.14
3.88
4.56
3 qi
4.13
4.76
4.97
4.75
4.85
4.57
3 Q2
3 fin
.3.28
3.9.3
4 06
3 31
4.31
3.86
3.74
3.71
4.45
4.042 •
n.71.31
5.274
1st STAGE
CLAR.
EFFL.
0.207
0 71 8
0.207
n.189
0.206
n 777
0.190
0.252
0.194
0.176
n.705
0.188
n 18fi
0.187
0.199
0.197
n 177
0.191
n 173
0 1^3
n 749
n.24i
0.235
n 777
0 iq4
0.197
0.222
0.199
0.215
0.209
0.2048
n.n208
10.171
2nd STAGE
CLAR.
EFFL.
0.082
n 077
0.075
o 077
0.066
n 073
0.076
0.102
0.071
0.071
0 . 075
n.064
n n.54
0.047
0.045
0.046
n 045
0.045
n.n.39
n 040
0.038
0.039
0.036
0.044
n.0.38
0.034
0.033
0.037
0.036
0.037
0.0544
0.0185
34.062
D.M.
FILTER
EFFL.
0.049
0 049
0.058
0 057
0.044
0 057
0.055
0.057
0.047
0.040
0.040
0.035
0.074
0.025
0.024
0.021
0.077
0.022
0.021
0.023
0.020
0.021
0.020
0.024
0.020
0.019
0.018
0.021
0.019
0.018
0.0322
0.0145
45.104
EFFL.
TO LAKE
0.039
0 044
0.047
0.046
0.045
0 055
0.050
0.058
0.047
0.041
0.041
0.0.3.3
0.027
0.024
0.024
0.022
0.024
0.023
0.028
0.024
0.021
0.021
0.022
0.025
0.021
0.023
0.019
0.023
0.022
0.020
0.0320
0.01212
37.942
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
93.6
94 0
94.8
95.1
95.4
94 1
95.1
93.6
94.8
95.7
94.7
95.9
95.2
95.5
95.8
96.0
96.3
96.1
•96.2
95.1
9.3.1
92.6
94.0
94.5
94.1
95.4
94.2
94.7
94.2
95.3
94.837
0.94522
0.99668
2nd STAGE
LIME
CLAR.
60.4
67 0
63.8
61.9
68.0
67 8
60.0
59.5
63.4
59.7
63.4
66.0
71.0
74.9
77.4
76.6
74.6
76.4
77.4
79.3
84.7
83.8
84.7
80.2
80.4
82.7
85.1
81.4
83.3
82.3
73.237
8.9600
12.234
DUAL-
MEDIA
FILTER
40.2
31 9
22.7
27.8
33.3
21 9
27.6
44.1
33.8
43.7
46.7
45.3
55.6
46.8
46.7
54.3
51.1
51.1
46.1
42.5
47.4
46.1
44.4
45.4
47.4
44.1
45.4
43.2
47.2
51.3
42.50
8.8158
0 . 20743
TERTIARY
PLANT
98.5
98 6
98.5
98.6
99.0
98 5
98.6
98.5
98.8
99.0
99.0
99.2
99.4
99.4
99.5
99.6
99.5
99.5
99.5
99.4
99.4
99.4
99.5
99.4
99.4
99.6
99.5
99.4
99.5
99.6
99.163
0.4097
0.4132
SEC. PLUS
TERT.
PLANT
98.7
98 9
98.4
99.1
99.6
99 7
99.8
99.6
99.4
99.7
99.6
99.7
99.8
99.6
99.9
99.8
99.9
99.6
99.9
99.7
99.6
99.9
99.8
99.9
99.57
0.3991
o.4ob|
EPA-280 (Cin)
(12-75)
-------
Table E-l (continued)
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Dec.
1973
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
V
SEC.
EFFL.
1st STAGE
CLAR.
INF.
4.21
3.88
4.42
4.13
.3.06
•* 70
3 88
•* QI
3.60
4,11
4.42
3.12
3.88
416
4.04
•^ Q7
4 38
4.18
4.00
4 ?Q
5.10
4.67
4 1^
4.47
3.23
* ?n
4.71
4 ?Q
4.63
4 76
4 81
4.125
0.23373
5.6662
1st STAGE
CLAR.
EFFL.
0.226
0.705
0.222
0 740
0.717
0 2?o
0 240
n 7^
0.747
o 2«8
0.248
0.7.38
0 744
0, 768
0.374
o wi
0 288
0.783
0.320
0.356
0 . 363
0.310
0 271
0.241
0.217
0 777
0.305
0 787
0.292
0 2^1
0 ^21
0.27039
0.04222
15.614
2nd STAGE
CLAR.
EFFL.
0.037
0.037
0.036
0 040
0.035
0 O^q
0 038
0 0^7
n.nsq
0 03q
0.041
0 . 0.37
0 039
o 047
0.045
o 045
0.044
0.044
0.042
0.047
0.050
0.048
o 040
0.042
0.040
n OAA
0.069
0 07^
0.065
0 051;
0 040
0.0449
0.00940
20.935
D.M.
FILTER
EFFL.
0.018
0,018
0.016
0 Oiq
0.013
n 020
0 018
n ni 6
0.01Q
o OIQ
0.019
0 015
O.OIQ
0 O1 8
0 070
0 021
0.018
0 OIQ
0.019
0.021
0.020
0.022
Q 020
0.020
0.020
n 074
0.038
0 04^
0.031
n 024
n n7i
0.0209
0.0061
29.244
EFFL.
TO LAKE
0.019
o OIQ
0.019
0 070
0 01 1
o 01°
0 018
o 018
0 0]Q
o 017
0.019
0.01Q
0 01Q
o OIQ
0,071
0 070
0.019
0 071
0.021
0.022
0.077
0.022
0 n2n
0.020
0.021
O O74
0.040
0 0^7
0.029
o 02^
p 02^
0.0214
0.00544
25 470
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
94.6
Q4 7
95.0
Q4 7
Q2 Q
04 Q
Q3 8
Q4 0
Q1? ^
93 0
94.4
Q7 4
Q3-7
Q1* 6
97 0
Q2 4
qV4
q^ 2
92.0
91.7
92. Q
93.4
Q? R
94.6
93.3
Q7 c;
93.5
Q3 ^
9.3.7
q* Q
03 ^
93.426
0.82622
0 88436
2nd STAGE
LIME
CLAR.
8.3.6
81 Q
83.8
8^ 1
8^ Q
82 3
84.2
84 t
S1^ Q
86 5
83 . 5
84 4
84 0
a? q
86 1
8^ 1
84 7
84 4
86.9
86.8
86.2
84 5
81 Q
82.6
81.6
«/i i
77.4
74 6
77.7
81 r 1
84 7
83.306
2.7227
3 2683
DUAL-
MEDIA
FILTER
51 .3
51 ^
55.6
52 5
62 Q
48 7
52.6
c;6 8
51 ^
51 3
53 7
5Q 5
51 3
61 7
55 6
c;^ ^
59 1
56 8
54.8
55.3
60.0
54 2
c;q 2
52.4
50.0
45.4
44.9
41 1
52.3
56.4
57 1
53.819
418624
9 0347
TERTIARY
PLANT
99.6
QQ 5
qq 6
QQ 5
QQ 6
99 5
99.5
qq 6
QQ 5
QQ 5
qq 6
qq <;
qq 5
qq 6
qq 5
qq c;
qq 6
qq c;
99.5
99.5
99 6
99 5
qq i;
99.6
99.4
QQ A
9Q.2
qq 0
99 . 3
99.5
QQ 6
99.493
0.12893
0 12959
SEC. PLUS
TERT.
PLANT
EPA-280 (Cin)
(12-75)
-------
Table E-l (continued)
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Jan.
1974
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
Q qy
19,3
16.4
5 R1*
5.68
5.22
5.00
q QR
7 04
12.6
10.4
6.09
10.7
R 7q
7.41
9.094
V 4.266
46.914
SEC.
EFFL.
•j; QJ
4.63
3.73
4 ??
6 nq
4.14
5,68
3.81
3.97
3.56
4.330
0.9062
20.928
1st STAGE
CLAR.
INF.
3.82
4.18
4 61
4.14
4 ?4
3 R4
4.39
A f.n
T, qq
4 43
4 06
/] -78
4.6*
4 qa
4 03
4 43
3.71
4 ^7
5.10
1 <;q
4.61
3. 88
3.88
3.96
4.18
5.54
3.97
5 in
6.41
5.68
5.32
4.4355
0.6407
14.444
1st STAGE
CLAR.
EFFL.
0.321
0 . 349
n ^60
0.404
n 471
0 . 364
0.407
n *oq
n •?«!
0 4^4
0 334
0 °99
0.30?
0,303
0 33?
n 3?i
0.307
n 777
0.31.3
n ^iq
0.37.3
0.432
0.463
0.428
0.366
0.306
0.288
0 ?q4
0.284
0.312
0.302
0,3473
0.05158
14.852
2nd STAGE
CLAR.
EFFL.
0.052
0.049
n oqo
0.051
0.059
0.060
0.059
n 06q
n 06q
n 06q
0 065
0 05°
0.052
0.047
0.056
n.n55
0.044
0.0.35
0.045
n nm
0.059
0.071
0.080
0.074
0.065
0.058
0.063
0.075
0.087
0.090
0.079
0,0608
0.0130
21.334
D.M.
FILTER
EFFL.
0.021
0.019
0 01Q
0.023
0.029
0.046
0.022
0 073
0.074
0,073
0 024
0 019
0.021
0.018
0.074
0.074
0.021
0.014
0.019
0 070
0.023
0.029
0.029
0.025
0.021
0.023
0.026
0.038
0.048
0.048
0.045
0,0261
0.009K
3b. Ibb
EFFL.
TO LAKE
0.021
0.002
0 07?
0.028
0.037
0.075
0.023
0:074
o.o??;
0.074
0,074
0.022
0.072
0.020
0.025
0.025
0.019
0.022
0.021
0.07.3
0.027
0.031
0.029
0.024
0.024
0.021
0.023
0.040
0.046
O.Q46
0.043
0,0261
0.00875
33.5by
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
91.6
91.6
92 2
90.2
90.1
90.5
90.7
91 .3
90.4
90.9
qi 8
93.0
93.5
93.4
91.8
92 7
91.7
93.6
93.9
91 .1
91.9
88.9
88.1
89.2
91.2
94.5
92.7
94.2
95.6
94.5
94.3
91.97
1,804
1.Q61
2nd STAGE
LIME
CLAR.
83.8
86.0
86.1
87.4
86.0
83.5
85.5
83.7
81 .9
82.9
80. 5
82.6
82.8
84.5
83.1
82.9
85.7
87.4
85.6
84.0
84.2
83.6
82.7
82.7
82.2
81.0
78.1
74.5
69.4
71.1
73.8
82.232
4,453
5 4151
DUAL-
MEDIA
FILTER
59.6
61.2
62.0
54.9
50.8
23.3
62.7
64.6
65.2
66.7
6.3.1
63.5
59.6
61.7
57.1
56.4
52.3
60.0
57.8
60.8
61.0
59.2
63.8
66.2
67.7
60.3
58.7
49.3
44.8
46.7
43.0
57.548
8.973
15.592
TERTIARY
PLANT
99.4
99.5
99.6
99.4
99.3
98.8
99.5
99.5
99.4
99.5
99.4
99.6
99.5
99.6
99.4
99.5
99.4
99.7
99.6
99.4
99.5
99.2
99.2
99.4
99.5
99.6
99.3
99.2
99.2
99.2
99.2
99,403
0.18K
0.182'
SEC. PLUS
TERT.
PLANT
99.5
99.9
99.9
99.6
99.8
99.6
99.6
99.6
99.6
99.8
yy.b1
99.7
99.8
99.6
99.4
99,68
0,147
0.148
EPA-280 (Cin»
(12-75)
-------
Table E-l (continued)
TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Feb.
1974
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
TOTAL PHOSPHORUS CONTRATION - mg/l
RAW
WASTE
9.83
9.32
8.01
9.79
6.12
8.37
7.22
7.15
9.28
8. 99
7.80
10.10
fi.QS
4.61
11.9
12.9
in.o
7.87
10.7
8.45
9.60
5.50
10.2
11.3
11.7
13.6
5.73
9.0007
V2.2475
24.970
SEC.
EFFL.
3.50
4.40
4.03
4.96
4.02
4.17
4.99
4.70
4.40
4.43
4.70
4.21
4.18
4.04
5.03
4.46
4.04
5.64
6.76
5.03
5.12
5.10
8.48
5.79
4.70
4.57
3.59
4.7793
1.0136
21.209
1st STAGE
CLAR.
INF.
3.61
4.40
4.45
5.54
9.54
6.51
5.86
6.34
5.82
5.86
7.42
6.79
7.44
5 . 53
8.09
6.34
5.82
8.06
6.16
9.38
7.65
5.29
5 . 50
7.24
6.11
7.48
6.80
9.61
6.5943
1.4908
22.608
1st STAGE
CLAR.
EFFL.
0.269
0.259
0.252
0.278
0.273
0.259
0.229
0.245
0.220
0.241
0.249
0.253
0.247
0.276
0.267
0.273
0.288
0.283
0.328
0.488
0.350
0.307
0.295
0.270
0.303
0.306
0.321
0.317
0.2838
0.0506
17.830
2nd STAGE
CLAR.
EFFL.
0.062
0.052
0.052
0.050
0.238
0.128
0.044
0.044
0.045
0.044
0.044
0.048
0.047
0.046
0.045
0.052
0.055
0.052
0.057
0.101
0.078
0.064
0.062
0 . 059
0.064
0.185
0.255
0.193
0.0809
0.0608
75.152
D.M.
FILTER
EFFL.
0.033
0.027
0.024
0.025
0.094
0.071
0.029
0.028
0.026
0.023
0.023
0.025
0.025
0.025
0.028
0.028
0.030
0.029
0.030
0.055
0.051
0.041
0.035
0.033
0.038
0.066
0.127
0.122
0.0425
0.0286
67.337
EFFL.
TO LAKE
0.030
0.026
0.025
0.042
0.090
0.070
0.030
0.029
0.025
0.027
0.025
0.027
0.027
0:027
0.027
0.029
0.030
0.029
0.039
0.053
0.043
0.039
0.037
0 . 036
0.039
0.088
0.127
0.088
0.0430
0.0258
59.903
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
92.5
94.1
94.3
95.0
97.1
96.0
96.1
96.1
96.2
95.9
96.6
96 . 3
96.7
95.0
96.7
95.7
95.0
96.5
94.7
94.8
95.4
94.2
94.6
96.3
95.0
95.9
95.3
96.7
95.525
1.041
1.0896
2nd STAGE
LIME
CLAR.
77.0
79.9
79.4
82.0
12.8
50.6
80.8
82.0
79.5
81.7
82.3
81.0
81.0
83.3
83.1
80.9
80.9
81.6
82.6
79.3
77.7
79.1
79.0
78.1
78,9
39.5
20.6
39.1
71.918
19.687
27.375
DUAL-
MEDIA
FILTER
46.8
48.1
53.8
50.0
60.5
44.5
34.1
36.4
42.2
47.7
47.7
47.9
46.8
45.6
37.8
46.1
45.4
44.2
47.4
45.5
34.6
35.9
43.5
44.1
40.6
64.3
50.2
36.8
45.304
6.9932
15.436
TERTIARY
PLANT
99.1
99.4
99.5
99.5
99.0
98.9
99.5
99.6
99.6
99.6
99.7
99.6
QQ.7
99.5
99.6
99.6
99.5
99.6
99.5
99.4
99.3
99.2
99.4
99.5
99.4
yy.i
98.1
98.7
99.361
0.34996
0.35221
SEC. PLUS
TERT.
PLANT
99.7
99.7
99.7
99.0
98.8
99.7
99.6
99.6
99.8
99.7
99.7
QQ 8
99.6
99.4
99.8
99.8
99.7
99.6
99.5
99.4
99.6
99.4
99.7
99.7
yy.4
99.1
97.9
99.50
0.405
0,407
EPA-280 (Cin)
(12-75)
-------
Table E-l (continued) TOTAL PHOSPHORUS DATA FOR 24-HOUR COMPOSITE SAMPLES
DATE
Mar.
1974
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
MEAN
STDDE
%CV
RAW
WASTE
5.12
5,78
5.30
6.08
5.79
4.93
5 . 25
s.ns
4.54
4.47
6.65
7. 06
11.4
8.82
5,54
6,65
6.99
7.29
7.51
8.02
7.81
11.7
10.6
14.5
7.Q2
n Q
9.46
8.81
9.70
8.69
9 = 85
7.7161
" 2.5075
32-497
TOTAL PHOSPHORUS CONTRATION - mg/l
SEC.
EFFL.
4.02
4.42
4.10
5.17
4.54
3,99
4.75
4.82
3.46
3.99
4.90
4.14
4.43
4.99
4.47
5,39
4.40
4.85
4.71
4.40
4.53
4.49
4o70
3.59
5.47
fi.fi*
4.68
5.2Q
3.93
4.00
4,31
4.5664
0.62198
.3,621
1st STAGE
CLAR.
INF.
8,19
6.55
6.58
6.48
5.62
9.60
4.74
7.92
4.99
4.11
7.15
8.12
9.78
5.15
5.01
5.12
5.03
4.70
5.98
4,76
7.12
5,48
6.23
4.07
4.34
7.20
5.26
5.11
4, fin
5_^
5.17
5 . 9835
1.5200
25.404
1st STAGE
CLAR.
EFFL.
0.247
0.345
0.217
0.224
0.319
0.373
0.209
0.220
0.260
0.267
0.290
0.319
0.249
0.263
0.370
0.271
0. 285
0.307
0.270
0,259
0.280
0,265
0.269
0.263
Oo270
0.355
0.278
0.321
0.256
0.252
0.267
0.2787
0,04230
15.176
2nd STAGE
CLAR.
EFFL.
0.161
0.140
0.134
0.114
0.301
0.335
0.105
0.107
0.121
0.129
0.133
0.134
0.130
0,105
0.133
0.122
oaoo
0.086
0.084
0.082
0.072
0.069
0.069
0.129
0.263
0.308
0.272
0.146
0.132
0.131
0.124
0.1442
0,07215
50,026
D.M.
FILTER
EFFL.
0.095
0.089
0.091
0.078
0.109
0.160
0.057
0.069
0.083
0.088
0.080
0.090
0.087
0,070
0.051
0.062
0.048
0.040
0.040
0.043
0.037
0.034
0.035
0.060
0.105
0.129
0.106
0.107
0.109
0.067
0.082
0.0774
0.03002
38.760
EFFL.
TO LAKE
0.065
0.065
0.065
0.053
0.076
0.082
0.052
0.053
0.058
0.074
0.069
0.086
0.063
0.070
0.070
0.061
0.049
0.041
0.040
0.041
0.040
0.038
0.047
0.076
0.089
0.091
0.099
0.055
0.049
0.044
0.063
0.0621
0.01663
26.798
REMOVAL THRU INDICATED PROCESS - PERCENT
1st STAGE
LIME
CLAR.
97.0
94.7
96.7
96.5
94.3
96.1
95.6
97.2
94.8
93.5
95.9
96.1
97.4
94.9
92.6
94.7
94.3
93.5
95.5
94.6
96.1
95.2
95.7
93.5
93.8
95.1
94.7
93.7
94.4
95.3
94,8
95.103
1.1915
1 2528
2nd STAGE
LIME
CLAR.
34.8
59.4
38 2
4Q.]
5.6
10.2
49.8
51.4
53.5
51.7
54.1
58.0
47.8
60.1
64.0
55.0
64.9
72.0
68.9
68.3
74.3
74.0
74.3
51.0
2.6
13.2
2.2
54.5
48.4
48.0
53.6
48.803
21.196
43.431
DUAL-
MEDIA
FILTER
41.0
36.4
32.1
31 .6
63.8
52 2
45.7
35.5
31.4
31.8
39.8
32.8
33.1
33.3
61.6
49.2
52.0
53.5
52,4
47.6
48.6
50.7
49.3
53.5
60.1
58.1
61.0
26.7
17.4
48.8
33.9
44.029
11:858
26.932
TERTIARY
PLANT
98.8
98.6
98.6
98.8
98.1
98.3
98.8
99.1
98.3
97.9
98.9
98.9
99.1
98.6
99.0
98.8
99.0
99.1
99.3
99.1
99.5
99.4
99.4
98.5
97.6
98.2
98.0
97.9
97.6
98.7
98.4
98.655
0.52079
052789
SEC. PLUS
TERT.
PLANT
98.1
98.5
98 ,3
98 7
98.1
96.8
98.9
98.6
98.2
98.0
98.8
98.7
99.2
99.2
99.1
99.1
99.3
99.5
99.5
99.5
99.5
99.7
99.7
99.6
98.7
98.9
98.9
98.8
98.9
99.2
99.2
98.88
0.620
0.627
EPA-280 (Cin)
(12-75)
-------
APPENDIX F
DISTRIBUTION OF OPERATION AND MAINTENANCE COSTS
116
-------
CHEMICALS
UTILITIES
EQUIPMENT-
PERSONNEL
SUPPLIES
FIGURE F-l. DISTRIBUTION OF OPERATION AND MAINTENANCE COSTS
-------
00
MAINTENANCE
AND BOILER
OPERATOR
FOREMAN §
SUPERVISOR
ACCOUNTANT
ENGINEER
LABORATORY
AND LABORATORY -
SUPERVISOR
OPERATORS
FIGURE F-2. DISTRIBUTION OF PERSONNEL COSTS
-------
CARBON DIOXIDE
OTHER
CHEMICALS
CHLORINE
SULFURIC ACID
POLYMER
LIME
FERRIC CHLORIDE
FIGURE F-3. DISTRIBUTION OF CHEMICAL COSTS
-------
ELECTRICITY
WATER
TELEPHONE
HEATING FUEL OIL
AND PROPANE
FIGURE F-4. DISTRIBUTION OF UTILITY COSTS
-------
GREASE § OIL
CUSTODIAL
SAMPLING
LABORATORY
FIGURE F-5. DISTRIBUTION OF MISCELLANEOUS COSTS
-------
MISC. REPAIR AND MAINTENANCE
ts)
tSJ
EQUIPMENT
REPAIR AND"
MAINTENANCE
SAFETY
EQUIPMENT
SLUDGE TRUCK
OPERATION
NEW EQUIPMENT
AND STRUCTURES
EQUIPMENT REPLACEMENT
AND SPARE PARTS
FIGURE F-6. DISTRIBUTION OF EQUIPMENT OPERATION AND REPAIR COSTS
-------
TECHNICAL REPORT DATA
fflease read /axructions on the reverse before completing)
|4. TITLE AND SUBTITLE
TERTIARY TREATMENT FOR PHOSPHORUS REMOVAL AT
ELY, MINNESOTA AWT PLANT, April, 1973 thru March, 1974
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
March 1976
. PERFORMING ORGANIZATION CODE
John W. Sheehy and Francis L. Evans, III
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
1 BB033
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above
1. ODWCDBBOT/GRANT NO.
S-802309
3. TYPE OF REPORT AND PERIOD COVERED
"nterim 4/1/73 - 3/31/74
4. SPONSORING AGENCY CODE
iPA - ORD
15. SUPPLEMENTARY NOTES
IMS report discusses the design, the construction and the first year's operation of
the 1.5 mgd tertiary treatment plant located in Ely, Minnesota The tertiary treat
""*0 dU" the ">"«" '-"on fro "
h
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Sewage Treatment
Sludge Disposal
Phosphorus
Chemical Removal
Operating Costs
(Sewage Treatment)
13. DISTRIBUTION STATEMENT
Release to Public
EPA Form 2220-1 (9-73)
b.lDENTIFIERS/OPEN ENDED TERMS
Shagawa Lake (Minnesota)
Lime-Clarification
Dual-media Filtration
Tertiary Wastewater
Operation and Maintenance
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS {Thispage)
Unclassified
c. COS AT I Field/Group
13B
21. NO. OF PAGES
133
22. PRICE
U.S. GOVERNMENT PRINTING OFFICE: 1976-657-695/5371 Region No. 5-11
------- |