WATER POLLUTION CONTROL RESEARCH SERIES • 12130 EZR 05/71
Combined Treatment of Domestic
and Industrial Wastes
by Activated Sludge
ENVIRONMENTAL PROTECTION AGENCY • WATER QUALITY OFFICE
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Water Pollution Control Research Series
The Water Pollution Control Research Reports describe
the results and progress in the control and abatement of
pollution in our Nation's waters. They provide a central
source of information on the research, development, and
demonstration activities in the Water Quality Office, in the
Environmental Protection Agency, through in-house research
and grants and contracts with Federal, State, and local agencies,
research institutions, and industrial organizations.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports System,
Water Quality Office, Environmental Protection Agency,
Washington, D. C. 20242.
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Combined Treatment of Domestic
and Industrial Wastes
by Activated Sludge
by
The City of Dallas, Oregon
for the
WATER QUALITY OFFICE
ENVIRONMENTAL PROTECTION AGENCY
Grant No. 11060 EZR
Project No. 12130 EZR
MAY 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.25
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EPA REVIEW NOTICE
This report has been reviewed by the Environmental Protection Agency and approved for
publication. Approval does not signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
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ABSTRACT
The operation of a completely aerobic secondary treatment facility for treatment of
combined domestic and industrial wastewater from the City of Dallas, Oregon, was
studied for a period of 15 months. The system was designed for an average daily flow of
2.0 mgd and a BOD load of 7000 pounds per day. The results of this study indicate the
flexibility and economy of the completely aerobic system, consisting of activated sludge
with aerobic digestion, for a small community with proportionately high industrial
wastewater loads. The effluent BOD concentration averaged 8 mg/1 and the effluent total
suspended solids concentration averaged 13 mg/1 for the 15-month study period. The
biological solids yield averaged about 0.7 pounds of solids per pound of BOD removed
and the net accumulation of biological volatile solids was about 0.42 pounds of volatile
solids per pound of BOD removed. These values were obtained with a MLSS
concentration range of 700 to 3000 mg/1, an average sludge age of 19 days and an
organic loading range of 0.05 to 0.40 pounds of BOD per pound of MLSS per day. Total
capital cost of the system was about 66 percent of that for a conventional activated
sludge plant and operation and maintenance costs were only about 33 percent of those
for a conventional system.
This report was submitted in fulfillment of Grant No. 11060 EZR under the partial
sponsorship of the Water Quality Office, Environmental Protection Agency.
in
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CONTENTS
SECTION PAGE
I CONCLUSIONS 1
II RECOMMENDATIONS 3
III INTRODUCTION 5
Scope 5
Background 6
Theoretical Considerations 7
IV TREATMENT FACILITIES 11
General Description 11
Design Concept 14
Design Criteria 14
Design Factors 15
V DEMONSTRATION PROCEDURES 23
Plant Startup 23
Operation 23
Sampling Schedule and Procedures 23
Analytical Methods 26
VI WASTEWATER CHARACTERISTICS 29
General 29
Canning Season 29
Dry Weather Non-Canning Season 34
Wet Weather Non-Canning Season 34
Infiltration 35
VII TREATMENT PLANT PERFORMANCE 37
General 37
Effluent Quality and System Stability 37
Aerobic Digestion 47
Solids Deposits 51
Velocity Profiles 51
Dissolved Oxygen Profiles 57
Oxygen Uptake Rates 57
PVC Liner 57
Operational Considerations 62
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CONTENTS - CONTINUED
SECTION PAGE
VIII FINANCIAL CONSIDERATIONS 63
Construction Costs
x--3
Operation and Maintenance Costs o:>
Total Annual Costs 63
IX DISCUSSION 65
Activated Sludge System °5
Aerobic Digestion "°
Chlorine Contact 75
X ACKNOWLEDGMENTS 77
XI REFERENCES 79
Xil PUBLICATIONS 81
XIII ABBREVIATIONS 83
XIV APPENDIXES 85
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FIGURES
NO. PAGE
1 Treatment Facilities 12
2 Schematic Plan 13
3 Aeration Basin, Typical Section 18
4 Aerobic Digester, Typical Section 20
5 Chlorine Contact Channel, Typical Section 21
6 Flow and Rainfall vs. Time 31
7 Influent BOD vs. Time, Weekly Average Data 32
8 BOD Loading (Ib/day) vs. Time, Weekly Average Data 33
9 Influent and Effluent BOD vs. Time, Weekly Average
Data 38
10 Influent and Effluent TSS vs. Time, Weekly Average
Data 39
11 Influent BOD and Effluent Total and Soluble BOD vs.
Time, Canning Season 43
12 BOD Removal vs. Time, Canning Season 44
13 Influent BOD and Effluent Total and Soluble BOD vs.
Time, Dry Weather Non-Canning Season 45
14 Influent BOD and Effluent Total and Soluble BOD vs.
Time, Wet Weather Non-Canning Season 46
15 Effluent Soluble BOD vs. Aeration Time 48
16 Organic Loading vs. Time, All Data 49
17 Solids Accumulation in Aeration Basin No. 1,
October 1970 52
18 Aeration Basin Velocity Profile, Two Aerators,
Low Speed (one foot) 53
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FIGURES - CONTINUED
NO. PAGE
19 Aeration Basin Velocity Profile, Two Aerators,
Low Speed (6 feet) 54
20 Aeration Basin Velocity Profile, Two Aerators,
Low Speed (9 feet) 55
21 Aeration Basin, Velocity Profiles 56
22 Aeration Basin D. O. Profile, Two Aerators,
Low Speed (one foot) 58
23 Aeration Basin D. O. Profile, Two Aerators,
Low Speed (6 feet) 59
24 Aeration Basin D. O. Profile, Two Aerators,
Low Speed (9 feet) 60
25 Aeration Basin D. O. Profiles 61
26 Substrate Removal vs. Effluent Soluble BOD 66
27 Clarifier Hydraulic Loading vs. Effluent Suspended
Solids 69
28 Clarifier Solids Loading vs. Effluent Suspended
Solids 70
29 Horsepower - Oxygen Transfer Relationships 71
30 Composition of Waste Sludge Solids 73
vin
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TABLES
NO. PAGE
1 Treatment Plant Design Criteria 14
2 Design Factors 16
3 Detailed Operation Schedule 24
4 Sampling and Testing Schedules 25
5 Influent Characteristics 30
6 Effluent Characteristics 40
7 Influent and Effluent Characteristics, All Data 41
8 Total Annual Costs 64
IX
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SECTION I
CONCLUSIONS
Operation of a completely aerobic wastewater treatment plant, designed to provide
secondary treatment of domestic and industrial wastes from the City of Dallas, Oregon,
has been studied during the period from August, 1969 through November 1970.
The following conclusions have been reached, based on the results of the study presented
in this report:
1. Effluent quality was good throughout the study period, even during such
extreme conditions as periods of flow at maximum hydraulic capacity during
the non-canning season.
2. Cannery startup, operation and shutdown have had no significant effect on the
operation of the treatment system.
3. The system is sufficiently stable to produce a good quality effluent with
aeration times varying from 4 hours to 60 hours.
4. The system has adequate flexibility and stability to withstand shock organic
and hydraulic loads.
5. The wastewater characteristics during the first year of operation more closely
resembled domestic wastewater as opposed to industrial wastewater
characteristics.
6. Effluent BOD averaged 8 mg/1 and effluent suspended solids averaged 13 mg/1,
for the entire study period.
7. The substrate removal coefficient, k, averaged about 0.041 and was not
significantly affected by changes in the temperature range of data encountered.
8. The biological sludge yield averaged about 0.7 pounds of solids per pound of
BOD removed.
9. Net biological volatile solids accumulation was about 0.42 pounds of volatile
solids per pound of BOD removed.
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10. The biodegradable portion of the solids wasted to the digester averaged about
19 percent of the total wasted solids.
11. Aerobic digestion is an effective and economical means of waste activated
sludge stabilization.
12. The average reduction in volatile solids content through the digester was 5
percent.
13. Digested sludge has been stabilized to the extent that no objectionable odors
have evolved from the humus storage ponds.
14. A treatment system of this type can be constructed and operated at substantial
savings in cost compared to a conventional activated sludge system.
15. Total capital cost was about 66 percent of the cost for a conventional 2 mgd
activated sludge plant.
16. Operation and maintenance costs for the first year averaged $33 per million
gallons treated, or about 33 percent of those for a conventional plant treating
the same average flow.
17. Total annual treatment cost averaged $0.097 per pound of BOD removed
(amortized capital cost portion of annual cost based on BOD removal capacity
rather than actual pounds of BOD removed).
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SECTION II
RECOMMENDATIONS
Analysis of the data obtained during the demonstration period indicates several areas
where design modifications or further operational studies would be desirable.
DESIGN MODIFICATIONS—Only minor design modifications are recommended and are
as follows:
The concrete protective pads beneath the aerators should be larger to prevent bottom
scour.
Measurement of recycled sludge flow with a propeller type meter is not satisfactory
because of frequent fouling of the propeller. A magnetic flowmeter would be preferred.
FUTURE STUDIES—Organic loadings to the plant during this study were low, relative to
design capacity. Analysis of some aspects of the treatment unit performances was very
difficult to achieve because of this. Therefore, it would be desirable to reevaluate some of
these analyses at loads closer to the design capacity. The extremely low solids loading
rate and the low degradability of the solids wasted to the digester during this study
precluded an accurate analysis of digester performance under a full range of operating
conditions. Future studies of the performance of the aerobic digester would be
particularly useful.
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SECTION III
INTRODUCTION
SCOPE
A completely aerobic system designed to provide secondary treatment of combined
domestic and industrial wastes was constructed at the City of Dallas, Oregon, and was
studied during the period from September 1969 through November 1970. This project
was financed with the aid of a research, development and demonstration grant provided
by the Environmental Protection Agency (EPA), under grant number 11060 EZR.
The basic purpose of this program was to demonstrate the economics and efficiency of
the completely aerobic treatment method when applied to the treatment of combined
domestic and industrial wastes from a small municipality.
The specific objectives were to:
1. Demonstrate, in full-scale plant operation, the BOD and suspended solids
removal capabilities and stability of the completely mixed, completely aerobic
system treating combined domestic and industrial waste flows from a small
municipality.
2. Determine the influence of rapidly changing industrial waste loadings resulting
from startup and shutdown of canning operations, changes in canning product,
and brief periods of cannery inactivity during the canning season.
3. Determine the efficiency and operating characteristics of the combined
treatment system during the off-canning season.
4. Determine the effect of varying the detention time in the aeration basins,
between 12 and 48 hours, on BOD and suspended solids removal and system
stability.
5. Demonstrate the applicability of aerobic digestion to biological treatment
systems serving small municipalities.
6. Study the quantity and character of aerobically digested sludge when varying
the liquid and solids detention time in the aerobic digester between 5 and 20
days.
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7. Demonstrate the savings in both construction and operating costs of the
completely aerobic treatment method when utilizing earthen basin construction
and floating mechanical surface aeration units for mixing and supplying oxygen
to the aeration basins and aerobic digester.
8. Demonstrate the use of polyvinyl chloride (PVC) sheet lining in waste
treatment plant construction.
BACKGROUND
Many small cities are faced with the problem of providing wastewater treatment services
to local industry. Waste loads from such industries as food processors are seasonal in
nature and may constitute the major organic load on the wastewater treatment plant.
These small cities therefore require a treatment system which will withstand these shock
loads, yet is economical enough to minimize the financial burden on the community. The
completely aerobic system was evaluated on this basis.
The City of Dallas, Oregon, retained the engineering firm of Cornell, Howland, Hayes &
Merryfield to design and supervise the construction of the treatment facility and to
exercise technical supervision over the research and development program.
An EPA research and development grant (No. 11060 EZR) was accepted by the City on
21 February 1968.
The treatment system receives a combination of domestic and commercial wastes,
cannery wastes, a limited quantity of slaughterhouse wastes and an occasional flow of
phenolic glue waste from a plywood mill.
The plant was designed to meet water quality requirements established by the Oregon
State Department of Environmental Quality, which state that effluent to the receiving
stream may contain not more than 20 milligrams per liter (mg/1) each of BOD and
suspended solids. The process employed was a completely mixed activated sludge system
with aerobic digestion of the waste solids.
A complete list of definitions of the technical terms used in this report may be found in
the WPCF Glossary [ 1 ], and a list of abbreviations and symbols used is contained in
Section XIII.
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THEORETICAL CONSIDERATIONS
MICROBIOLOGY-The living organisms found in activated sludge are classified as either
plants or animals. The plants consist of bacteria and fungi and the animals are primarily
protozoa, rotifers and nematodes.
Hawkes [2] stated that bacteria are normally dominant as primary feeders on organic
wastes, with different holozoic protozoa being secondary feeders, and rotifers and
nematodes are found at the higher levels in the food chain. Fungi cannot normally
compete with bacteria, but they may predominate as primary feeders if certain conditions
exist, such as: low pH, nitrogen deficiency, or low dissolved oxygen [3].
High-carbohydrate wastes are also reported to stimulate fungi growth.
The composition of the organic waste determines which bacterial genera will predominate
[2,3]. Protein wastes favor Alcaligenes, Flavobacterium, and Bacillus, while carbohydrate
waste favors Pseudomonas. A high population of free swimming bacteria will sustain free
swimming ciliata as the predominate protozoa; however, if the food level is lowered by a
reduction in the free swimming bacterial population, the free swimming ciliates will yield
to stalked ciliates which require less energy.
Rotifers thrive in very stable systems and are better indicators of stable conditions than
are the nematode worms.
METABOLISM— The metabolic reactions which occur within activated sludge can be
divided into three phases: (1) oxidation, (2) synthesis, and (3) endogenous respiration.
These three phase reactions can be illustrated with the following general 'equations, which
have been formulated by Weston and Eckenfelder [4] :
(1) Organic Matter Oxidation
CxHyOz + aO2 -* xCO2 + bH2O + Energy
y z
where a = x + — ---
(2) Cell Material Synthesis
CxHyOz + NH3 + dO2 + Energy -* C5H7NO2 +eCO2 + fH2O
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, , x + y z
where d = 5
4 2
e = x - 5
(3) Cell Material Oxidation
C5H7NO2 + 5O2 — «5CO2 + 2H2O + NH3 + Energy
In the presence of enzymes, produced by living microorganisms, about one-third of the
organic matter removed is oxidized to carbon dioxide and water, to provide energy for
synthesis to cell material of the other two-thirds of the organic matter removed [5]. The
cell material is also oxidized to carbon dioxide, water, etc., by endogenous respiration
(auto-oxidation).
KINETICS-Several authors [6,7,8] have formulated mathematical equations for design
and operation of complete-mix activated sludge plants. Some of these formulations are
more easily used for evaluation of full-sized plant operation than others. Eckenfelder's
basic equations [7,9] are of this nature and are presented below.
SUBSTRATE UTILIZATION -The Michaelis-Menton relationship was used to define the
microbial growth rate and steady state substrate removal in a completely mixed system,
and a simplified equation for substrate removal was developed:
sa sf sr
where Sr = BOD removed, Ibs per day
Sa = influent BOD, Ibs per day
Sf = soluble effluent BOD, Ibs per day
Se = soluble effluent BOD, mg/1
Xa = average mixed liquor volatile suspended solids, Ib
t = aeration time, days
k = removal rate coefficient (Ib BOD/day/lb MLVSS) per mg/1 BOD
The equation shows that the substrate removal is proportional to the product of the
MLVSS and the aeration time. This equation is valid only for conditions in which the
actual substrate concentration is much less than the substrate concentration at one-half
the maximum reaction rate (Michaelis Constant). A low effluent soluble BOD from a
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completely mixed system indicates a low substrate concentration since the effluent
soluble BOD is the same as the soluble BOD in the aeration basin. Therefore, the above
condition is met if the effluent soluble BOD is consistently low.
SLUDGE YIELD—Excess solids in the activated sludge system will result from the
non-biodegradable suspended solids in the influent and the biological cells synthesized in
the system during BOD removal, less the quantity of cell mass synthesized which is
broken down by endogenous respiration.
McCarty and Brodersen [10] have presented an equation which gives the net sludge
accumulation in terms of pounds of volatile biological solids produced per pound of BOD
removed, as follows:
0.53
0.65 - B
where A =
F =
E -
M =
b =
bM
net accumulation of volatile biological solids
BOD removed
suspended solids lost from system per day
total suspended solids in system
endogenous respiration constant
This equation shows that the net accumulation of solids is dependent on the rate of
synthesis of biological solids, the rate of solids degradation by endogenous respiration and
the sludge age of the system.
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SECTION IV
TREATMENT FACILITIES
GENERAL DESCRIPTION
Figure 1 is an aerial photograph of the treatment system. The photograph was taken just
prior to completion of construction.
Waste flow from the City's collection system enters the plant through a 36-inch diameter
influent sewer at the pump station (1). The raw waste is pumped through an 18-inch
pipeline to the headworks (2). The waste is shredded by the comminutor (3) and then
flows to the aeration basin splitter box (4) where it is discharged to one or both aeration
basins (5). The effluent from the aeration basin flows by gravity to the clarifier (6) where
the activated sludge is settled.
The activated sludge to be returned to the aeration basin is removed from the clarifier by
means of six suction pipes mounted on the revolving clarifier mechanism and flows by
gravity to the return sludge pump station located nearby (7). Two sludge pumps, sized to
return 25 to 100 percent of the plant dry weather design flow, lift the activated sludge
back up to the splitter box (4).
Excess, or waste, sludge is collected on the bottom of the clarifier by a revolving scraper
arm and pumped directly to the aerobic digester (8) through sludge pumps located in the
control building (9).
The effluent from the clarifier flows by gravity through the flow measurement box (10)
to the chlorine contact channel (11) and is finally discharged through the outfall (12)
into LaCreole Creek.
A sludge pump located in the control building transfers the digested sludge to one, or
both, humus storage ponds (13) where it is further stabilized and dried. The supernatant
from the humus ponds flows by gravity to the plant influent line (1).
Figure 2 is a schematic diagram of the treatment system, showing flow pattern and
locations of sampling points, flow metering, control valves and gates, and pumps.
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10
1. RAW SEWAGE PUMP STATION
2. HEADWORKS
3. COMMINUTOR
4. AERATION BASIN SPLITTER BOX
5. AERATION BASINS (2)
6. FINAL CLARIFIER
7. RETURN SLUDGE PUMP STATION
8. AEROBIC DIGESTER
9. CONTROL BUILDING
10. FLOW MEASUREMENT BOX
11. CHLORINE CONTACT CHANNEL
12. OUTFALL SEWER
13. SLUDGE LAGOONS (2)
FIGURE 1
TREATMENT FACILITIES
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HEADWORKS
c
RAW SEWAGE
INFLUENT
LEGEND
CONTINUOUS & AUTOMATIC
SAMPLING POINT
OTHER SAMPLING POINTS
CONTINUOUS FLOW METERING
CONTROL VALVE OR GATE
CONSTANT SPEED PUMP
TO PLANT
INFLUENT
EMERGENCY
DIGESTED SLUDGE OVERFLOW
AERATION
BASIN
NO 1
HUMUS POND
NO. 2
CONTROL BUILDING
PUMP ROOM
DIGESTED
SLUDGE
D
AEROBIC
DIGESTER
UNDIGESTED
SLUDGE
AERATION
BASIN
SPLITTER BOX
SLUDGE RECIRC-
ULATION PUMPS
SLUDGE
RECIRCULATION
CHLORINE CONTACT
CHAMBER
7
TREATED EFFLUENT
TO STREAM
AERATION
BASIN
NO. 2
CLARIFIER BYPASS
FIGURE 2
SCHEMATIC PLAN
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DESIGN CONCEPT
The design was based on the need to minimize the following shortcomings often
associated with conventional activated sludge designs: high construction costs; high
operating labor costs; need for highly trained operators; susceptibility to upset by shock
organic, hydraulic and toxic loads; and waste solids handling, stabilization and disposal
problems.
These shortcomings were minimized by use of the following design concepts:
Primary clarification and grit removal facilities were eliminated. Grit will settle in the
aeration basins and will be removed periodically by heavy equipment. The aeration
capacity was increased to compensate for the greater organic load to the aeration basins.
Aerobic digestion was employed in place of the higher cost conventional anaerobic
digestion.
Earthen basins, with shotcrete sideslope linings, were used in place of higher cost
reinforced concrete construction.
The complete-mix activated sludge principle, designed for a conservative range of organic
loadings and adequate hydraulic surge capacity, was employed to reduce susceptibility to
process upset. Hydraulic surge capacity was provided by the use of narrow aeration basin
outlets which provide a more uniform basin effluent flow, and allowance for a
fluctuation of about one foot in the basin water level.
The use of aerobic digestion and automatically controlled sludge pumping simplifies waste
solids handling and disposal problems.
DESIGN CRITERIA
The criteria used for final design of the City of Dallas wastewater treatment plant are
listed in Table 1.
TABLE 1
TREATMENT PLANT DESIGN CRITERIA
POPULATION
Present 5,900
Design 10,400
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FLOW (MGD)
Present Average 0.94
Design Average 2.00
Design Maximum, day 6.00
Peak Instantaneous 7.00
BOD LOAD (LB/DAY)
Canning Season 7,080
Non-Canning Season 2,080
Population Equivalent^
Canning Season 41,600
Non-Canning Season 12,200
EFFLUENT REQUIREMENTS
Maximum BOD (mg/l) 20
Maximum S.S. (mg/l) 20
Includes 5,000 Ib/day industrial BOD
2Based on 0.17 Ib BOD/capita/day
DESIGN FACTORS
The design factors used for the major unit and equipment selection are listed in Table 2.
Photographs of several of the major units are included in Appendix A. Appendix B lists
the manufacturers of the major equipment items. The major treatment units are described
below.
Each aeration basin provides a volume of 1.0 million gallons. The basins were constructed
of earth with a reinforced concrete ring wall and shotcrete lined sideslopes. A typical
section through the aeration basin is shown on Figure 3. Oxygen is supplied to each basin
by four 25-hp, two-speed, floating mechanical aerators. The maximum water depth is 12
feet. The design was based on an organic loading of 0.23 Ib BOD/lb MLVSS (26 Ib
BOD/1000 C.F.) and an aeration time of 24 hours at design BOD loading.
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TABLE 2
DESIGN FACTORS
INFLUENT PUMPS
Number 2
Type Centrifugal
Capacity 2400 gpm
Total Head 26 feet
HEADWORKS
Sewage Grinder
Number 1
Size 25-inch
AERATION BASINS
Number 2
Depth 12 feet
Volume (each) 1.0 million gallons
Hydraulic Capacity (each) 6.0 mgd
Design Organic Loadings1 0.23 Ib BOD/lb MLVSS/day
(26 Ib BOD/1000 cu. ft./day)
AERATION EQUIPMENT
Number of Aerators (each basin) 4
Type 2-speed, floating, mechanical surface type
Size 25-hp
CLARIFIER
Number 1
Diameter 60 feet
Side Water Depth 10 feet
Surface Overflow Rate2 707 gal/d/sq. ft.
Solids Loading Rate2'3 26 Ib/d/sq. ft.
Detention Time2 2.5 hours
Sludge Removal Revolving suction arm
SLUDGE RECIRCULATION
Number of Pumps 2
Type 1 single-speed
1 variable-speed
Recirculation Ratio2 0.25 to 1.0
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FLOW MEASUREMENT
Plant Flow
Recycled Sludge Flow
Waste Sludge
CHLORINATION
Type
Control
Prop, meter, clarifier discharge
Prop, meter behind pumps
Time clocks, constant pump rate
V-notch chlorinator
Plant flow
CHLORINE CONTACT
Unit
r\
Detention Timez
Outfall and chlorine contact channel
1.55 hours
SLUDGE DIGESTION
Number
Type
Volume
Detention Time4
4000 mg/l solids to digester
8000 mg/l solids to digester
Oxygen Supply and Mixing
Minimum Digested Sludge Age4
4000 mg/l solids to digester
8000 mg/l solids to digester
DIGESTED SLUDGE DISPOSAL
Method
Number
Area, each
Total
Supernatant Drainage
Operation
EFFLUENT POLISHING
Method
o
Detention Time^
1
Aerobic flow-through without thickening
480,000 gallons
5.2 days
10.4 days
30-hp floating mechanical aerator
15.2 days
20.4 days
Humus ponds
2
67,000 sq. ft.
3.1 acres
Return to plant
Dry to 3-foot depth of water
Discharge to humus pond No. 1
20 hours
1At 3500 Ib. BOD/day/basin and 2200 mg/l MLSS
^At average design flow of 2.0 mgd
3At 2200 mg/l MLSS and 1.0 recirculation ratio
4At design loading
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GRAVEL BACKFILL
NOTES: BASIN SYMMETRICAL ABOUT
CENTER LINE. CONCRETE PADS
PLACED UNDER EACH AERATOR
FIGURE 3
AERATION BASIN
TYPICAL SECTION
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The 60-foot diameter clarifier has a 10-foot sidewater depth. Recycled activated sludge is
removed by a rapid sludge withdrawal mechanism utilizing suction pipes mounted on the
scraper arms. Waste sludge is scraped to the center of the unit and removed through a
sludge hopper. The design was based on a hydraulic overflow rate of 707 gal/day/sq. ft.
and a solids loading of 26 Ib/day/sq. ft. at a mixed liquor flow of 4.0 mgd and a mixed
liquor suspended solids (MLSS) level of 2,200 mg/1.
The maximum capacity of the aerobic digester is 480,000 gallons. The basin is 90 feet in
diameter with a maximum water depth of 12 feet. The digester construction is similar to
that of the aeration basins, i.e., earth basin with a reinforced concrete ring wall and
shotcrete lined sideslopes. Figure 4 is a typical section through the aerobic digester.
Oxygen is supplied to the basin by a single-speed 30-hp floating mechanical aerator. The
design was based on a hydraulic detention time, at design loading, of 10.4 days with a
waste sludge solids concentration of 8000 mg/1.
Chlorine contact time is provided in a shotcrete lined channel, 450 feet in length. The
design provides a 1.55 hour contact time at average design flow. A typical section
through the chlorine contact channel is shown on Figure 5.
The control building houses the plant motor control center, automatic samplers,
laboratory, and waste sludge pumps.
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to
O
NOTES: BASIN SYMMETRICAL ABOUT
CENTER LINE. CONCRETE PAD
PLACED UNDER AERATOR
FIGURE 4
AEROBIC DIGESTER
TYPICAL SECTION
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EARTHEN-
EMBANKMENT
GRAVEL BACKFILL-
NOTE: DISCHARGE OVER CONCRETE WEIR
FIGURE 5
CHLORINE CONTACT CHANNEL
TYPICAL SECTION
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SECTION V
DEMONSTRATION PROCEDURES
PLANT STARTUP
Initial aeration basin startup was accomplished as described below.
Prior to startup, the aeration basins were partially filled with water, to test the aerator
operation. Aeration basin number 2 was seeded with 8,000 gallons of secondary sludge
from the City's old trickling filter plant, and approximately one cubic yard of barnyard
manure obtained from an adjacent farm. All four aerators were run at low speed to mix
the basin contents and increase the dissolved oxygen level. Raw wastewater flow into the
basin was begun after one day of aeration and was gradually increased to 0.75 mgd over
a period of about one week. Three days were required to fill the basin because of the
low initial flow. All biological solids produced were returned to the aeration basin until
the MLSS reached the desired level.
Acclimation of the system was monitored with daily COD determinations on both
influent and effluent flows and suspended solids analyses of the aeration basin contents.
The system was assumed to be completely acclimated after approximately four weeks of
operation when the daily COD removals leveled off above 90 percent.
Aeration basin number 1 was started after basin number 2 became acclimated. All of the
activated sludge was returned to basin number 1 for 36 hours prior to the addition of
any wastewater. The entire wastewater flow was diverted to the basin at the end of this
period.
OPERATION
The treatment system was operated continuously from August 1969, through November
1970. Table 3 is a detailed schedule of operations during the demonstration period.
SAMPLING SCHEDULE AND PROCEDURES
Samples were taken at various locations throughout the system. These sample point
locations are shown on Figure 2, and are described below. All subsequent discussion of
sample points will refer to Figure 2. Table 4 lists the sampling and testing schedules used
throughout the demonstration period.
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TABLE 3
DETAILED OPERATION SCHEDULE
DATE
AUGUST 1969
SEPTEMBER
OCTOBER
NOVEMBER
DEC. 1969
JAN. 1970
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
NOV^Z°
CANNERY111
OPERATION
I GREEN
-j-l BEANS
jt PRUNES
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BEANS
P
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AERATION
BASINS USED
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AVERAGE
PLANT FLOW (mgd)
START-UP & A
ACCLIMATION V
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AVERAGE12'
AERATION TIME (hrs.
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CM
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MLSS<3> (mg/l)
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AEROBIC DIGESTER
DETENTION TIME (days)
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DATE
AUGUST 1969
SEPTEMBER
OCTOBER
NOVEMBER
DEC. 1969
JAN. 1970
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
NOV. 1970
(1) CANNERY OPERATION BASED ON ACTUAL RECORDS FOR 1969 AND 1970 ADDITIONAL PRODUCTS MAY BE PRODUCED IN THE FUTURE.
(2) AERATION TIME WAS SET BY THE NUMBER OF AERATION BASINS IN OPERATION AND THE INFLUENT FLOW RATE.
(3) MIXED LIQUOR SUSPENDED SOLIDS.
-------
TABLE 4
SAMPLING AND TESTING SCHEDULES
(NUMBER OF TESTS PER WEEK)
CANNING SEASON (JULY 15 TO SEPT. 30)
SAMPLE POINT
A PLANT INFLUENT
B AERATION BASIN
EFFLUENT
C WASTE ACTIVATED
SLUDGE
C AEROBIC DIGESTER
E PLANT EFFLUENT
f POLISHING POND
EFFLUENT
BOD TOTAL
3
-
3
*
Q
111
^
o
a
0
0
ca
-
-
3
SUSPENDED SOLIDS
TOTAL
3
3
3
3
3
*
VOLATILE
3
3
3
3
3
il I
SETTLEABLf
5
5
-
5
a
5
5
5
5
LU
CC
TEMPERATU
10
10
10
5
DISSOLVED
OXYGEN
5
5
5
5
COLIFORM
-
-
1
, —
NITROGEN11
1
-
1
CM
w
^)
PHOSPHORO
1
-
1
ALKALINITY
3
3
3
3
CHLORINE
RESIDUAL
-
-
5
O
MICROSCOPI
EXAM
-
1
1
-
NON-CANNING SEASON (OCT. 1 TO JULY 14)
SAMPLE POINT
A PLANT INFLUENT
B AERATION BASIN
EFFLUENT
C WASTE ACTIVATED
SLUDGE
D AEROBIC DIGESTER
E PLANT EFFLUENT
F POLISHING POND
EFFLUENT
O
O
O
m
2
_
_
-
2
.
Q
II |
_I
O
to
to
Q
O
O
m
_
-
1
SUSPENDED SOLIDS
TOTAL
2
2
2
2
2
*
VOLATILE
2
2
2
2
2
_
SETTLEABLE
3
3
_
-
3
_
a
3
3
3
3
UJ
oc
TEMPERATU
5
5
5
5
DISSOLVED
OXYGEN
5
5
5
5
_
COLIFORM
Bi-
Weekly
—
_
-
Bi-
Weekly
_
^
NITROGEN (
Tri-
Weekly
—
-
Tri-
Weekly
_
CM
--J
PHOSPHOROi
Tri-
Weekly
_
-
Tri-
Weekly
ALKALINITY
2
2
2
2
I CHLORINE
RESIDUAL
_
—
-
5
0
MICROSCOPI
EXAM
1
_
1
_
(1) TOTAL KJELDAHL, AMMONIA AND NITRATE
(2) TOTAL AND ORTHOPHOSPHATE
* SAMPLING FREQUENCY AS REQUIRED
-------
PLANT INFLUENT—Automatic 24-hour composite samples, proportional to plant flow,
were obtained by pumping from the headworks, downstream of the comminutor. This
location is shown as sample point A on Figure 2. The automatic sampler, sample pumps
and storage refrigerator are located in the control building.
AERATION BASIN EFFLUENT-These samples were obtained by manually compositing
grab samples during the daily 8-hour operating period. The location is shown as sample
point B.
WASTE ACTIVATED SLUDGE-Grab samples taken at the waste sludge pump were
mixed to form a composite sample during the operating period. The location is shown as
sample point C.
AEROBIC DIGESTER—Sample point D shows the location of these samples, which were
manually mixed to form composites from grab samples taken from the digester at the
outlet box.
PLANT EFFLUENT-Automatic 24-hour composite samples, proportional to plant flow,
were obtained by pumping from the clarifier effluent line at the flow measurement box,
upstream from the point of chlorine injection. The sampler and pump are located in the
control building adjacent to those for the plant influent. This sample location is shown as
sample point E.
POLISHING POND EFFLUENT-Samples of the polishing pond effluent (sample point
F) were not taken on a regular schedule after acclimation of the system since, after this
period, the polishing pond was used only for effluent bypass while the chlorine contact
channel was cleaned. The majority of the samples were grab samples taken at the
entrance to the outfall pipe.
ANALYTICAL METHODS
All analyses, with the exception of nitrogen, phosphorous and coliform tests, were
performed in the plant laboratory. Nitrogen, phosphorous and coliform analyses were
performed at the EPA's Pacific Northwest Water Laboratory in Corvallis, Oregon.
All plant testing was done in accordance with the twelfth edition (1965) of "Standard
Methods for the Examination of Water and Wastewater" of the American Public Health
Association [11], with the following exceptions:
SUSPENDED SOLIDS-Suspended solids tests were performed using Whatman No. 541
hardened ashless filter discs instead of asbestos mats.
26-
-------
Settleable solids were measured by both the volume method and the weight method. Use
of the weight method was discontinued early in the program because of the very small
quantity of settleable solids encountered.
Nitrogen and phosphorous tests were performed in accordance with the FWPCA manual
[12].
A list of laboratory equipment used for the analytical testing is included in Appendix B.
-27
-------
SECTION VI
WASTEWATER CHARACTERISTICS
GENERAL
Influent wastewater data was separated into three different categories to obtain a more
meaningful analysis. The three categories are as follows: (1) canning season, (2) dry
weather non-canning season, and (3) wet weather non-canning season.
The canning season normally extends from about 15 July through 30 September, and the
wet weather non-canning season from 10 December through 20 March. The dry weather
non-canning season occurs in two separate periods: 1 October through 9 December, and
21 March through 14 July.
Table 5 lists average, maximum, minimum and standard deviation data for the various
parameters used to evaluate the influent wastewater characteristics. These values were
calculated from data for each category described previously. These data are discussed in
the following paragraphs.
CANNING SEASON
ALKALINITY AND pH—The influent wastewater alkalinity during the canning season
varied from 68 mg/1 to 129 mg/1 with an average value of 99 mg/1, as CaCOg. The pH
varied from 6.0 to 7.4 and averaged 7.0.
TEMPERATURE AND DISSOLVED OXYGEN (D.O.)-The temperature ranged from 14
degrees C to 22 degrees C and averaged 20 degrees C. The minimum D.O. level was 0.3
mg/1, the maximum level was 1.7 mg/1, and the average was 0.5 mg/1.
FLOW—The wastewater flow averaged about 1.0 mgd during this period and varied from
a minimum of 0.4 mgd to a maximum of 2.4 mgd. Figure 6 shows influent flow vs. time
for the demonstration period.
BIOCHEMICAL OXYGEN DEMAND (BOD)-The influent BOD averaged 166 mg/1 (1108
Ib/day) and ranged from 59 mg/1 (497 Ib/day) to 635 mg/1 (3813 Ib/day). Figure 7 shows
influent BOD in mg/1 vs. time and Figure 8 shows influent BOD in Ib/day vs. time for
the total operating period.
-29-
-------
I M F L U E N T
CANNING SEASON * * * *
TABLE 5
CHARACTERIST
FLOW (MGO)
bOD (MG/L)
BOO (LB/D)
TSS (MG/L)
TSS (LB/D)
VSS (MG/L)
VSb (LB/D)
ALK (MG/L)
PH
TtMP (OEG C)
D.O. (MG/L)
TKN (MG/L)
NH3-N (MG/LI
NO3-N (MG/L)
T-PO4 (MG/L)
O-PO4 (MG/L)
AVG.
0 . 9 B
165.8
1107.7
1 24.3
908.7
62.7
577.5
98.5
7.0
19.6
0.5
14.4
4 .9
1 .0
5.4
3.2
MAX.
2.39
635.0
3813.0
552.0
3314.6
232.0
2109.0
129.0
7.4
22.0
1 .7
35.5
11.7
9.6
7.2
5.8
MIN .
0.42
59.0
496 .a
2fl.O
233.5
14.0
113.2
68.0
6.0
14.0
0.3
1 .4
0. 1
0.0
3.9
1 .3
STD.
DEV.
0.27
1 26.7
624.6
110.3
637. 1
48.5
492.7
14.4
0.3
1 .2
0.2
1 1 .5
3.8
3.0
1 . 1
1 .4
* * * *
AVG.
1.18
95.3
880.5
94. 1
966.5
76.5
798.2
97.0
7.2
15.7
1.3
10.0
5.7
1 .6
5.2
3.6
DRY HEATHER
NON-CANNING
« * * * »ET WEATHER
NON-CANNING
MAX.
4.97
195.0
2353.8
320.0
5631.1
320.0
5261.6
132.0
7.6
21.0
6.0
22.9
10.0
7.2
7.2
6.9
MIN.
0.60
35.0
304.7
8.0
98.0
1 .0
8.9
48.0
6.6
8.0
0.3
0. 1
0.8
0. 1
1 .9
1 .6
STD.
DEV.
0.55
31.2
338. 1
62.7
942.9
63.8
972.2
18.7
0. 1
2.3
1 .0
7.4
3.2
2.8
1 .5
1 .6
AVG.
3.66
MAX.
7. 1 1
40.4 123.0
1023.9 2988.0
65.2 310.0
1891.1 13107.9
48.9 260.0
1429.6 10993.7
56.8 91.0
7. 1
1 1 .5
4.5
7.7
4.3
1 . 1
2.4
1 .4
7.5
16.0
7. 1
13.3
5.6
2.3
3.9
2.7
MIN.
0.87
6.0
222. 1
12.0
458.6
2.0
78.9
37.0
6.7
9.0
1 .6
0.4
3.3
0.2
0.9
0.3
STD.
D6V.
1 .76
26.2
613.4
59.8
2401.7
52.2
2022.2
12.5
0. 1
1 .7
1.9
6.5
1.1
1 .0
1 .«
1 .2
-------
SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV
CO
en
SEPT. OCT. NOV. DEC. JAN
1969
FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV.
1970
C.S. = CANNING SEASON
D.W.N.C. = DRY WEATHER NON-CANNING
W.W.N.C. = WET WEATHER NON-CANNING
FIGURE 6
FLOW AND RAINFALL VS. TIME
-------
g
to
C.S.
W.W.N.C.
D.W.N.C.
C.S.
D.W.N.C.
W.WJM.C.
OQ
SEPT. OCT. NOV. DEC. JAN.
1969
FEB. MAR. APR.
MAY JUNE JULY AUG. SEPT. OCT. NOV.
1970
FIGURE 7
INFLUENT BOD VS. TIME
WEEKLY AVERAGE DATA
-------
SEPT. ' OCT. NOV. DEC. JAN. FEB. MAR. ' APR. MAY ' JUNE JULY ' AUG. ' SEPT. ' OCT. ' NOV
1969 1970
FIGURE 8
BOD LOADING (LB./DAY) VS. TIME
WEEKLY AVERAGE DATA
-------
TOTAL AND VOLATILE SUSPENDED SOLIDS (TSS, VSS)-The average TSS was 114
mg/1 of which 63 mg/1, or 51 percent, was VSS. The range was from a low TSS value of
28 mg/1 (14 mg/1 VSS) to a high of 552 mg/1 (232 mg/1 VSS).
NUTRIENTS-The BOD:nitrogen:phosphate ratio in the influent wastewater averaged
100:8.7:3.3. The average ammonia nitrogen concentration was 4.9 mg/1, and the total
phosphate concentration averaged 5.4 mg/1.
DRY WEATHER NON-CANNING SEASON
ALKALINITY AND pH-The influent wastewater alkalinity during the dry weather
non-canning season varied from 48 mg/1 to 132 mg/1 and averaged 97 mg/1, as CaCX^.
The pH ranged from 6.8 to 7.6 and averaged 7.2.
TEMPERATURE AND D.O.-The average influent temperature during this period was 16
degrees C with a range from 8 degrees C to 21 degrees C. The D.O. level ranged from 0.3
mg/1 to 6.0 mg/1 with an average of 1.3 mg/1.
FLOW-The influent flow varied from 0.6 mgd to 5 mgd, as shown by Figure 6, and
averaged 1.2 mgd for this period.
BOD—.The average influent BOD was 95 mg/1 with a range from 35 mg/1 to 195 mg/1.
BOD to the plant, in pounds per day, averaged 880 and varied from 305 Ib/day to 2550
Ib/day. These relationships are shown on Figures 7 and 8.
TSS AND VSS-The average TSS concentration was 94 mg/1 of which 76.5 mg/1 or 81
percent was volatile.
NUTRIENTS-The average BOD:nitrogen:phosphate ratio was 100:10:5.5.
WET WEATHER NON-CANNING SEASON
ALKALINITY AND pH-The alkalinity ranged from 37 mg/1 to 91 mg/1 and averaged 57
mg/1, as CaCO3, during the wet weather non-canning season. The pH range was from 6.7
to 7.5 and the average pH was 7.1.
TEMPERATURE AND D.O.—The temperature of the influent wastewater averaged 11.5
degrees C and varied from 9 degrees C to 16 degrees C. D.O. levels ranged from 1.6 mg/1
to 7.1 mg/1 and averaged 4.5 mg/1.
34-
-------
FLOW—Referring again to Figure 6, the influent flow varied from 0.9 mgd to 7.1 mgd,
and averaged 3.7 mgd.
BOD-The average BOD during this period was 40 mg/1 (1024 Ib/day) and ranged from 6
mg/1 (222 Ib/day) to 123 mg/1 (2988 Ib/day). These relationships are also shown on
Figures 7 and 8.
TSS AND VSS-TSS averaged 65 mg/1 and varied from 12 mg/1 to 310 mg/1. VSS
averaged 49 mg/1 and varied from 2 mg/1 to 260 mg/1.
NUTRIENTS—The average BOD:nitrogen:phosphate ratio during the wet weather
non-canning season was 100:19:6.
INFILTRATION
The flow data discussed above shows a wide variation in the quantity of wastewater
received at the plant. Figure 6 shows the correlation between plant flow and rainfall data.
In general, during the wet weather, the peak flows are associated with rainy periods. This
phenomenon is primarily due to infiltration of groundwater into the sewer system. This
effect is much less prevalent in the summer and fall before the ground has become
saturated.
-35-
-------
SECTION VII
TREATMENT PLANT PERFORMANCE
GENERAL
The plant was scheduled for startup prior to the beginning of the 1969 canning season.
However, due to construction delays, startup was not accomplished until near the peak
canning period in August. Following startup, the plant was operated continuously
through November 1970, including the full 1970 canning season.
EFFLUENT QUALITY AND SYSTEM STABILITY
Influent and effluent wastewater quality parameters were monitored throughout the
operating period to provide a basis for analysis of the system stability and performance.
These data were analyzed in conjunction with other variables which affect the operation
of biological systems.
EFFLUENT QUALITY-Figure 9 is a plot of weekly average influent and effluent BOD,
in mg/1, vs. time, for the entire operating period. Figure 10 is a similar plot for influent
and effluent total suspended solids data. These figures show a consistently good effluent
quality throughout the year, regardless of the influent loading, flow, or operating
temperature encountered.
A summary of effluent data is listed in Table 6. This summary is separated into canning
season, dry weather non-canning season, and wet weather non-canning season. It includes
average, maximum, minimum and standard deviation values for all effluent data for each
period. A summary of influent and effluent average, maximum, minimum and standard
deviation data for the entire demonstration period is listed in Table 7.
During the canning season, the effluent BOD averaged 7.8 mg/1 with a maximum value of
16 mg/1. The average effluent TSS was 11.8 mg/1 and ranged from 1 mg/1 to 31 mg/1.
The average BOD and TSS values during the dry weather non-canning period were,
respectively, 8.4 mg/1 and 13.9 mg/1.
The averages during the wet weather non-canning season were 7.3 mg/1 BOD and 13.9
mg/1 TSS.
-37-
-------
MAY JUNE JULY ' AUG. SEPT. OCT. NOV
SEPT. OCT. NOV. DEC. JAN.
1969
FIGURE 9
INFLUENT AND EFFLUENT BOD VS. TIME
WEEKLY AVERAGE DATA
-------
SEPT. OCT. NOV. DEC.
1969
JAN. FEB.
MAR. APR. MAY JUNE JULY AUG.
1970
SEPT. OCT. NOV.
FIGURE 10
INFLUENT AND EFFLUENT TSS VS. TIME
WEEKLY AVERAGE DATA
-------
BOD (MG/L)
bOO (LB/D)
SOL BOD ( MGL )
TSS (MG/L)
TSS (LB/O)
VSS (MG/L)
VSS (LB/D)
ALK (MG/L)
PH
TEMP (DEC C)
D.O. (MG/L)
TKN (MG/L)
NH3-N (MG/L)
NQ3-N (MG/L)
T-P04 (MG/L)
0-P04 (MG/L)
* * * *
AVG.
7.76
66.6
2.4
11.6
109.4
7.6
73.7
62.8
7. 1
19.6
5.0
2.3
0.5
3.5
4.4
4.2
E F F
CANNING SEASON » *
MAX. MIN.
16.00 3.00
1 34.2
6.0
31.0
496. 7
25.0
326.0
93.0
7.5
22.0
8.6
10.5
5.6
16.4
6.7
6. 1
25.0
1 .0
1 .0
6.7
1 .0
6.7
27.0
6.5
16.0
3.2
0.2
0.0
0.4
1 .1
3.0
L u e N
* *
STD.
DEV.
2.93
2R.6
1 .4
7.8
95. 1
7.4
83.7
18.4
0.2
1 .4
1 .3
2.8
1.6
4.7
1.5
1 .0
T C H A
* * * *
AVG.
8.42
83.9
3.5
13.9
1 38.3
12.3
122.2
34. 1
7.0
17.5
6.0
3.3
0.8
5.9
5.3
4.3
RACTERIST
DRY HEATHER * *
NON-CANNING
MAX. MIN.
22.00 3.0O
224. 1
9.0
40.0
366.6
46.0
540.4
65.0
7.4
21.0
10.0
12. 3
5.0
10.2
7.8
6.4
23.5
1 .0
1 .0
8.7
1.0
6.6
7.2
6.6
7.2
3.5
1 .1
0.0
0.3
2.6
2.3
1 C S
* *
STD.
OEV.
4.05
51.8
2.9
9.2
99.2
10.2
112.5
1 1.6
0. 1
2.5
1. 1
3.2
1.5
3.2
1.5
1 . 1
* * * *
AVG.
7.32
211.2
2.6
13.9
451 .0
11.8
377.8
38.7
7.1
14.6
6.5
1 .1
0.2
5.1
2.1
1.8
WET HEATHER * •
NON— CANN ING
MAX. MIN.
20.00 2.00
835.6
5.0
68.0
1916.8
42.0
1607.7
66.0
7.4
16.0
8.9
1.6
0.6
7.0
3.4
3.2
23.5
1 .0
1 .0
16.9
1.0
1 1 .9
23.0
6.5
13.0
4.4
0.6
0.0
3.1
0.9
0.3
« *
STD.
DEV.
5. 16
195.9
1 .3
13.3
466.2
10. a
376.9
8.1
0. 1
o.a
1.0
0.3
0.2
1.7
1.4
1.3
-------
TABLE 7
INFLUENT AND E F
CHARACTERIST
-ALL DATA-
CHARACTERIST 1C AVERAGE MAXIMUM MINIMUM STANDARD
DEVIATION
FLOW (MGD) 1.84 7.11 0.42 1.54
BOD ( MG/L ) 103.9 635.0 6.0 88.9
BOD (LB/D) 983.5 3.813.0 222.1 517.0
SOL BOD (MGL)
TSS (MG/L) 96.6 552.0 8.0 82.7
TSS (LB/D) 1,178.5 13.107.9 98.0 1.444.0
VSS (MG/L) 65.3 320.0 1.0 57.7
VSS (LB/D) 912.? 10.993.7 8.9 1,301.3
ALK (MG/L) 85.8 132.0 37.0 24. «
PH 7.1 7.6 6.0 0.2
TEMP (DEG C) 15.7 22.0 8.0 3 .
-------
CANNERY STARTUP, OPERATION AND SHUTDOWN-Figure 11 is a plot of influent
and effluent BOD and effluent soluble BOD vs. time, during the canning season.
The plant was started up during the 1969 canning season. The peak BOD loads shown on
Figure 11 for the period from 9 September through 12 September, however, were not
attributable to waste from the cannery. During this period, a high concentration of
plywood glue waste appeared in the plant influent. There was, however, no significant
deterioration of effluent quality as a result of these peak loads.
The peak BOD load during the 1970 canning season was significantly less than for the
1969 season, even after eliminating the peaks associated with the glue waste. This can
probably be attributed to a poor crop yield in 1970. The peak period again occurred
during September with no significant loss in effluent quality.
There appeared to be no significant effect on effluent quality as a result of cannery
startup or shutdown. This could be partially due to a gradual increase and decrease in
processing by the cannery.
Figure 12 shows percentage of BOD removal during the same period of time. BOD
removal during the canning season was greater than 90 percent most of the time. The
efficiency dropped to about 88 percent following the 1969 cannery shutdown. However,
a comparison with Figure 11 shows that only a small increase in effluent BOD was
observed and the reduced efficiency was principally due to the reduction in influent BOD
concentration.
The drop in efficiency to about 86 percent BOD removal following cannery startup in
1970 was due only to a reduction of influent BOD concentration. A further comparison
with Figure 11 shows no change in effluent BOD concentration during this period.
NON-CANNING SEASON OPERATING CHARACTERISTICS-Figure 13 is a plot of
influent BOD and effluent total and soluble BOD vs. time for the dry weather
non-canning season. This plot shows a wide fluctuation in influent waste strength,
resulting mainly from large variations in flow. However, the effluent BOD concentration,
and particularly the soluble portion, maintained a uniform level throughout the period,
indicating a stable system.
Influent BOD and effluent total and soluble BOD data are plotted on Figure 14 for the
wet weather non-canning season. The influent BOD fluctuated widely as during the dry
weather period. Again, this is due principally to the wide variation in flow rate. Effluent
total BOD varied to a greater extent than during the dry weather period. However,
42
-------
-1^
OJ
EFFLUENT
SOLUBLE
1970
FIGURE 11
INFLUENT BOD AND EFFLUENT TOTAL AND SOLUBLE BOD VS. TIME
CANNING SEASON
(19 JULY 1969 - 27 SEPT 1969, 24 JULY 1970 - 28 SEPT. 1970)
-------
s
s
,8
UJ
o:
Q
O
GO
SEPT.
1969
A \
"OCT. N \ JULY
AUG.
1970
SEPT.
FIGURE 12
BOD REMOVAL VS. TIME - CANNING SEASON
(19 JULY 1969 - 27 SEPT. 1969, 24 JULY 1970 - 28 SEPT. 1970)
-------
OCT.
NOV.
DEC. MAR.
APRIL
MAY
JUNE
JULY
OCT.
1969
1970
NOV.
FIGURE 13
INFLUENT BOD AND EFFLUENT TOTAL AND SOLUBLE BOD
VS. TIME - ORY WEATHER NON-CANNING SEASON
(6 OCT.. 1960 - 7 DEC, 1969, 23 MARCH, 1970- 19 JULY 1970, 5 OCT. 1970 - 8 NOV. 1970)
-------
o
oS
GO
DEC.
1969
JAN.
FEB.
MAR.
\\
NOV.
1970
FIGURE 14
INFLUENT BOD AND EFFLUENT TOTAL AND SOLUBLE BOD
VS. TIME - WET WEATHER NON-CANNING SEASON
(8 DEC. 1969 - 22 MARCH 1970. 9 NOV. 1970 - 31 NOV. 1970)
-------
effluent soluble BOD was uniform throughout the period, indicating that the variation in
effluent quality was mainly due to solids carryover. However, these fluctuations were
relatively minor since the effluent total BOD concentration was well below the effluent
requirement nearly all the time.
EFFECT OF VARYING DETENTION TIME-Figure 15 is a plot of effluent soluble BOD
vs. aeration basin detention time. A significant conclusion is difficult to reach from
studying this figure. All data fall within a range of values so small that the difference
between the maximum and minimum values is nearly insignificant. The data appear to be
quite scattered. However, the scatter occurs over a very small range of soluble BOD
values.
From this figure it appears that there is no significant influence on BOD removal
efficiency from varying the detention time, at least in the range of loadings encountered
in this study.
ORGANIC LOADING—Figure 16 is a plot of organic loading vs. time for the full
operating period. In general, the load varied between 0.05 and 0.15 Ib BOD per Ib MLSS
per day, with peak rates as high as 0.4 Ib BOD per Ib MLSS per day. The SVI averaged
77 for the entire period. The average sludge age for the demonstration period was 19.5
days.
AEROBIC DIGESTION
GENERAL—The aerobic digester was operated continuously throughout the
demonstration period. Pumping times' to and from the digester were recorded along with
the respective solids concentrations. Several other parameters such as pH, D.O.,
temperature, and alkalinity were monitored to provide a basis for determination of the
digester performance.
DIGESTER PERFORMANCE-Solids loading to the digester was much lower than
originally anticipated. The average loading rate over the entire period of operation was
about 10 Ib V.S./day/lOOO cu. ft.
Digester performance was evaluated on the basis of the following two parameters: (1)
reduction in volatile solids content, and (2) net volatile solids destruction. Both
parameters were calculated from average values of the data for the entire demonstration
period.
-47-
-------
a
o
m
LU
_l
CO
+ +
ID
_J
LL.'
U_
LU
* * *»
•H- «•••• +M- <*•«•<*>
•»• * <*> «• *** •*> <*>
I
10
—I—
20
?0 40 50
RERRTION TIME (HOURS)
so
70
FIGURE 15
EFFLUENT SOLUBLE BOD
VS. AERATION TIME
-------
W.W.N.C.
SEPT
OCT. NOV.
1969
DEC. " JAN. " FEB. " MAR. ' APR
MAY JUNE ' JULY ' AUG. ' SEPT. ' OCT. ' NOV. '
1970
FIGURE 16
ORGANIC LOADING VS. TIME
ALL DATA
-------
Reduction in volatile solids content was calculated by the following formula:
R: Dv
VS Reduction (%) = 1 - — ^ x -i x 100
Di RV
where Rj = fraction of inert solids in raw sludge
Dj = fraction of inert solids in digested sludge
Dy = volatile fraction of digested sludge
RY = volatile fraction of raw sludge
Net reduction of volatile solids was based on the ratio of total pounds of volatile solids
removed from the digester to total pounds of volatile solids applied corrected for change
in volatile solids concentration in the digester and quantity of volatile solids applied to
fill the digester initially.
The average reduction (in percentage of total) of volatile solids content for the
demonstration period was 5 percent. The net volatile solids destruction for the same
period (calculated in pounds) was about 34 percent. The average digester detention time
was 69 days. The basin temperature averaged about 12 degrees C and the pH averaged
5.1 with an average alkalinity of 17 mg/1.
QUANTITY AND CHARACTER OF DIGESTED SLUDGE-The quantity of sludge
wasted to the humus ponds was calculated from the data recorded for pumping time and
solids concentration of the digested sludge. The total quantity of digested sludge wasted
to the humus ponds during the demonstration period was about 265,000 pounds (dry
solids basis), or an average of 670 Ib/day. The average volatile solids content of this
sludge was about 63 percent.
The relative drying character of the digested sludge was observed during the early summer
of 1970, when the supernatant was drained from the sludge in one of the humus ponds.
Some odor was present for a short period of time when the sludge was exposed to the
air. However, the odor, much like that of a barnyard although less intense, was not
objectionable and disappeared with the formation of a crust on the sludge layer.
The wet sludge, which had a maximum depth of about 1.5 feet, required a period of
about 3 months to dry completely. The maximum depth of sludge in the pond after
drying was about 6 inches. The sludge formed individual clumps upon drying, as shown
by a photograph of the dried sludge included in Appendix A. The relatively long period
required for complete drying of the sludge was primarily due to inability to drain out the
water which was trapped underneath the sludge blanket.
-50-
-------
The length of time before removal of the solids from the humus storage pond will be
required was estimated to be a minimum of three years, based on the quantity of solids
accumulated in one humus storage pond during the study period.
SOLIDS DEPOSITS
Aeration basin number 1 was drained after about 14 months of operation, to determine
the quantity of solids which had accumulated in the basin. Prior to dewatering the basin,
the biological solids were washed out by recycling water from the polishing pond back
through the plant, without returning activated sludge to the aeration basin. Pumping was
begun after reducing the MLSS level as low as possible. All four aerators were run while
pumping, to keep the residual MLSS in suspension.
A visual observation of the condition of the basin bottom was made. Figure 17 is a
sketch of aeration basin number 1, showing the condition of the bottom, after 14
months operation. Appendix A contains photographs of the basin, showing bottom scour
and solids deposits.
Bottom scour was evident around the concrete target pads beneath the aerators. The
maximum depth of scour was about 15 inches.
Solids deposition was generally light. The greatest accumulation occurred adjacent to the
aerator location in the northeast corner of the basin. The maximum depth of solids in
this location was about 1.5 feet. The solids consisted mainly of non-degradable plastic
materials and appeared to contain a relatively small amount of grit. The overall quantity
of solids deposited was relatively insignificant. Removal of solids from the basin should
not be required for a period of at least five years, based on these observations.
VELOCITY PROFILES
Velocity measurements were made in Aeration Basin No. 1 under different operating
conditions. Typical examples of velocity profiles are shown in Figures 18, 19 and 20,
(plans at different depths) and Figure 21 (section) for one set of operating conditions.
Velocity profiles for other operating conditions are included in Appendix C. The numbers
shown on the aerators indicate the operating horsepower of each unit.
Measurements were made from a boat using a Gurley No. 622 propeller-type current
meter. These data provide an evaluation of the mixing characteristics in the basin at
different power levels and provides an indication of possible low velocity areas where
solids settling might occur.
51
-------
LEGEND
SOLIDS
SCOUR
FIGURE 17
SOLIDS ACCUMULATION IN AERATION
BASIN NO. 1 - OCTOBER 1970
S"1
-------
DEPTH OF READINGS: 1 FOOT
C
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE 18
AERATION BASIN VELOCITY PROFILE
TWO AERATORS - LOW SPEED
-53
-------
DEPTH OF READINGS: 6 FEET
c
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE 19
AERATION BASIN VELOCITY PROFILE
TWO AERATORS - LOW SPEED
- 54
-------
A
DEPTH OF READINGS: 9 FEET
C
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE 20
AERATION BASIN VELOCITY PROFILE
TWO AERATORS - LOW SPEED
-55
-------
SECTION A - 2 AERATORS, LOW SPEED
SECTION B - 4 AERATORS, LOW SPEED
FIGURE 21
AERATION BASIN
VELOCITY PROFILES
-------
Analysis of the profiles for the minimum operating conditions (two aerators low speed)
shows bottom velocities in the range of 0.4 to 0.5 fps, found by Eckenfelder [7] to be a
minimum for uniform suspension of solids.
DISSOLVED OXYGEN PROFILES
Dissolved oxygen (D.O.) measurements were taken at different depths in aeration basin
number 1 under different operating conditions. The D.O. readings were taken from a
boat using a YSI meter and field probe. Figures 22, 23 and 24 show D.O. profiles at
different depths in the basin and Figure 25 is a D.O. profile section through the basin.
These figures show a higher D.O. concentration toward the south side of the basin.
Ammeter readings indicated a greater current draw and thus a higher horsepower output
from the aerators on that side of the basin. This difference is indicated by the operating
horsepower shown on each aerator. This resulted in a greater transfer of oxygen to the
mixed liquor and, therefore, higher D.O. readings.
OXYGEN UPTAKE RATES
Several oxygen uptake measurements were taken on grab samples of aeration basin and
aerobic digester mixed liquors. The tests were conducted by the following procedure: A
two-liter bottle was filled with the sample, a YSI D.O. probe was inserted and the top of
the bottle was sealed. D.O. readings were taken at regular intervals until the oxygen was
depleted. The sample was mixed continuously during the test by a magnetic stirrer with
teflon stirring bar.
The oxygen uptake data was plotted as dissolved oxygen used vs. time. These figures are
included in Appendix C.
The aeration basin oxygen uptake rates varied from 0.155 to 1.03 mg ©2 per day per mg
MLVSS at a temperature range of 17.5 to 19 degrees C. The aerobic digester oxygen
uptake rate averaged about 0.012 mg 02 per day per mg MLVSS. No detailed analysis of
the system oxygen requirements was made because not enough data were available to
establish a relationship between oxygen uptake and BOD removals.
PVC LINER
The original demonstration plan involved the use of PVC (polyvinyl chloride) sheet liner
in the aeration basins and aerobic digester. The City subsequently elected to use shotcrete
liners in these units instead of PVC, at an additional cost of about $0.25 per square foot.
However, since one of the grant objectives was to evaluate the use of PVC as a lining
-57-
-------
DEPTH OF READINGS: I-FOOT
C
ROTATION OF AERATORS
IN OPERATION
D.O. IN MG/L
FIGURE 22
AERATION BASIN D.O. PROFILE
TWO AERATORS - LOW SPEED
-58
-------
DEPTH OF READINGS: 6 FEET
ROTATION OF AERATORS
IN OPERATION
D.O. IN MG/L
FIGURE 23
AERATION BASIN D.O. PROFILE
TWO AERATORS - LOW SPEED
-59-
-------
DEPTH OF READINGS: 9 FEET
( .ROTATION OF AERATORS
^IN OPERATION
D.O. IN MG/L
FIGURE 24
AERATION BASIN D.O. PROFILE
TWO AERATORS - LOW SPEED
-60-
-------
n
SECTION C - 2 AERATORS, LOW SPEED
n
SECTION D - 4 AERATORS, LOW SPEED
FIGURE 25
AERATION BASIN
D.O. PROFILES
-------
material, several PVC strips were placed in the aeration basin, to be removed and tested
at periodic intervals. The first specimens were removed after one year of submergence,
and the following tests were performed: Grabes Tear Test (ASTM D1000-4) and tensile
and elongation tests (ASTM D882). The tests were performed by the General Engineering
Department of Oregon State University.
The tests showed no detrimental effect on the physical properties of the PVC material.
The complete test results are included in Appendix E.
OPERATIONAL CONSIDERATIONS
Relatively few operating problems were encountered. Those affecting plant operation
were mechanical problems involving equipment. These are described in the following
paragraphs.
AERATION EQUIPMENT-Shortly after plant startup, a bearing failure occurred in one
of the mechanical aerator gearmotors. This necessitated startup of the other aeration
basin. Subsequent operation resulted in similar failures in four of the eight remaining
aerators. The cause of this problem was isolated as a failure to lubricate these bearings
during assembly of the units at the factory.
RECYCLED SLUDGE PUMP STATION-A delay in delivery of these pumps resulted in
use of a temporary pumping facility. Very little control of the sludge recirculation rate
was possible for a period of several weeks.
WASTE SLUDGE PUMPS-A problem with the waste sludge pump motors was
encountered which limited control of the sludge wasting rate. The problem, which
involved motor overheating and shutdown, was corrected by replacing the motors on
both pumps. The sludge wasting rate was affected for an 8-month period.
Another problem developed which affected sludge wasting rate. A leak in the pump
suction line allowed air to enter the pump, thus reducing the pump capacity. This
condition affected operation for a period of about 2 months. The sludge pump automatic
time clock failed to operate properly on several occasions, resulting in a rapid reduction
in MLSS concentration in the aeration basin.
AUTOMATIC SAMPLERS—A mechanical problem with the automatic sampler timing
device required manual sampling of the influent and effluent flows during the first 4
months of operation. The sample quality suffered somewhat as a result of this problem
even though the samples were manually mixed to form composites during the operating
shift.
-62-
-------
SECTION VIII
FINANCIAL CONSIDERATIONS
CONSTRUCTION COSTS
The total capital cost for construction of the treatment facility, including engineering and
land costs, was $605,470. A detailed cost breakdown is included in Appendix D.
Comparison of this total with a total cost of $913,000 for a conventional activated
sludge plant, obtained from Smith's curves [13] and updated to 1968, indicates a
substantial saving in capital costs.
OPERATION AND MAINTENANCE COSTS
The total operation and maintenance costs for the first year of operation were $32,700.
Operation and maintenance costs for the plant, after deducting costs attributable only to
the demonstration program, were $22,200 and represent the normal yearly cost for
running the plant. The added costs due to the demonstration program were attributed to
additional sampling and testing requirements, supervision and data analysis. A detailed
breakdown of operation and maintenance costs is included in Appendix D.
Michel [14] reported annual operation and maintenance costs, for activated sludge plants
treating an average daily flow of 1.0 mgd, ranging from about $21,000 to $70,000 with
an average cost of about $37,000 per year (costs updated to 1970). The operation and
maintenance cost of $22,200 for the Dallas plant was about 60 percent of the average.
Smith [13] reported average operation and maintenance costs, for activated sludge plants
treating an average daily flow of 1.0 mgd, of about $100 per million gallons treated
(costs updated to 1970). Operation and maintenance costs at the Dallas plant averaged
$33 per million gallons treated or about 33 percent of Smith's figure.
TOTAL ANNUAL COSTS
Table 7 lists total annual costs of the treatment system for the first year of operation.
Total annual costs include: 1) annual capital amortization costs (6 percent interest, 20
years), 2) annual operation and maintenance costs, and 3) equipment replacement and
depreciation costs (5 percent of equipment capital cost).
-63-
-------
TABLE 8
TOTAL ANNUAL COSTS
Item Annual Cost
Capital Cost $605,470
Amortized Capital Cost (6%-20 years) 52,800
Annual Operation and Maintenance Cost 22,200
Estimated Equipment Replacement
and Depreciation 6,800
TOTAL ANNUAL COST $81,800
On the basis of this total annual cost, and the total pounds of BOD removed during the
year, cost of treatment was calculated as $0.258 per pound of BOD removed.
This unit cost appears to be higher than would normally be expected. However, the plant
has been operated far below the BOD loading capacity and high infiltration into the
collection system results in a very dilute waste during wet weather periods. Therefore, the
cost per unit of BOD is increased because of the required operation of units not related
to BOD removal.
A more realistic approach would be to calculate unit cost for the amortized capital cost
portion of the annual cost, based on available BOD loading capacity rather than on BOD
removal. The unit cost, calculated on this basis, was $0.097 per pound of BOD removed,
and included $0.026 per pound of BOD based on debt service and depreciation and
$0.071 per pound of BOD removed based on operation and maintenance costs.
-64-
-------
SECTION IX
DISCUSSION
ACTIVATED SLUDGE SYSTEM
MICROBIOLOGY— The system was operated at a relatively long sludge age, which tends
to favor the higher forms of organisms. Periodic microscopic examinations revealed the
presence of a wide range of organisms, ranging from bacteria through rotifers, during
different periods throughout the demonstration program.
The system appeared to operate most efficiently when a moderately large population of
rotifers and a large population of stalked ciliates were present in the activated sludge. The
moderate rotifer population indicated that the system was very stable, as discussed in
Section III.
Very few filamentous organisms were observed, although some nitrification occurred in
the aeration basins throughout the period. However, the alkalinity of the wastewater was
sufficient to buffer the system, thus minimizing the conditions favorable to filamentous
growth.
The predominant protozoa identified in the activated sludge during the periods of most
efficient operation were the stalked ciliates Vorticella campanula and Vorticella
microstoma.
SUBSTRATE REMOVAL-Substrate utilization in the activated sludge system, as
previously discussed in Section III, is described by the following equation:
kS =
6
The substrate removal rate, k, is equal to the slope of the first order curve passing
through the origin, on a plot of total pounds of BOD removed per day per pound of
MLVSS vs. mg/1 of effluent soluble BOD. Figure 26 is a plot of substrate removal vs.
effluent soluble BOD for all data obtained during the demonstration period.
The field data plotted on Figure 26 show considerable scatter, as may be expected. For
this reason, the curve from the origin was drawn through the mean coordinates of the
data points.
-65-
-------
(/D
ZD
C/3
EFFLUENT SOLUBLE
FIGURE 26
SUBSTRATE REMOVAL VS. EFFLUENT SOLUBLE BOD
-------
This figure includes data for a relatively wide range of temperatures (9 degrees C 24
degrees C). Three separate curves were plotted initially, for data of three different
temperature ranges. Substrate removal rate coefficients obtained from these plots,
however, showed no reasonable variation with temperature as described in the literature
[15, 16, 17]. Therefore, it was concluded that, within the range of operation
experienced, the substrate removal coefficient is not affected significantly by
temperature.
The average substrate removal coefficient, k, calculated from the data plotted on Figure
26, was 0.041. This value agrees closely with the data for domestic wastewater presented
by Eckenfeldef [15], but is somewhat higher than the coefficients obtained for potato
processing wastewater [17] and fruit processing wastewater [16]. This indicates that the
composition of the wastewater influent to the treatment plant at Dallas is predominantly
domestic in nature.
CANNERY STARTUP, OPERATION AND SHUTDOWN-The discussion of the nature of
the influent wastewater presented in the previous paragraph is reflected by the lack of
effect on plant operation of cannery startup and shutdown.
The peak BOD loads to the system occur during the canning season. However, no
significant change in effluent quality has resulted from these peaks. The gradual increase
and decrease of processing load at the cannery tends to reduce the shock load effect of
cannery startup and shutdown.
The distance from the cannery to the treatment plant may have some effect on the
strength of the canning waste. It is likely that a significant BOD reduction occurs in the
sewer between the cannery and the treatment plant since the canning waste is highly
soluble and the detention time is relatively long.
The canning waste is also substantially diluted by the domestic wastewater and by
infiltration into the system, resulting in a lower BOD concentration at the treatment
plant.
EFFLUENT QUALITY-The effluent quality data presented in Section VII give an
indication of the flexibility and stability of the system. The effluent quality was
consistently good during a wide range of operating conditions. The wide variation in flow
through the plant resulted in a large fluctuation of aeration time. During the wet weather
flows, aeration times were as low as 3.4 hours.
The organic loading rate, in general, varied between 0.05 and 0.15 Ib BOD per Ib MLSS
per day. This range of loading rates is somewhat lower than the values generally
-67-
-------
considered desirable for efficient operation of activated sludge systems. However, a check
of the effluent BOD values plotted on Figure 9 shows that an effluent of extremely good
quality was maintained at these low loadings. The organic loading was particularly low
during the wet weather non-canning season due to the low influent BOD. Some control
of the organic loading was accomplished by reducing the MLSS level. However, a
minimum MLSS level of 700 mg/1 was maintained to provide a resistance to shock loads
from glue waste discharges and to minimize washout of solids during peak flow periods.
Aeration basin temperatures varied from 9 degrees C to 24 degrees C. The low
temperature periods generally coincided with periods of low organic loadings and short
aeration times, resulting in conditions highly unfavorable for biological treatment.
However, the stability of the system prevented the occurrence of a poor-quality effluent.
CLARIFIER OPERATION-Figure 27 is a plot of clarifier hydraulic loading vs. effluent
suspended solids. Clarifier overflow rates varied from about 200 gallons per day per
square foot to as high as 2500 gallons per day per square foot during wet weather
periods. The scatter of the data on this plot shows that there is very little correlation
between clarifier efficiency and hydraulic loading rate. However, efficiency of the clarifier
was good at all ranges of loading, indicating a reasonably stable activated sludge system.
Clarifier solids loadings were plotted vs. effluent suspended solids on Figure 28. These
loadings ranged from a low of about 4 pounds per day per square foot to as much as 50
pounds per day per square foot. Analysis of this figure yields the same conclusions as
discussed in the preceding paragraph for hydraulic loading.
OXYGEN TRANSFER—Each aerator is capable of transferring to water, at standard
conditions, a minimum of 1180 pounds of oxygen per day at high speed and at least 50
percent of that amount on low speed.
Figure 29 is a plot of operating horsepower vs. oxygen transfer capacity. Listed on this
curve are the points of operation possible to achieve with the aeration equipment
available. This indicates the wide range of flexibility of the system.
AEROBIC DIGESTION
VOLATILE SOLIDS REDUCTION-The average reduction (in percentage) of volatile
solids content of the waste sludge was about 5 percent. The long sludge age (19 days
average) in the activated sludge system contributed to this low percentage of volatile
reduction as indicated by Loehr [18]. Another factor affecting the reduction in volatile
content was the relatively low average VSS content of the waste sludge (63 percent).
-68-
-------
U-g
10
CJ
a
l/D
a:g
or
a
o
o .
-------
o
CO
CD
_J
a
«
oo
Q
o
LU
a:
NOTE: CURVE FIT BY METHOD
OF LEAST SQUARES
12 18 *4 30
EFFLUENT 5- S- IM&/L)
FIGURE 28
42
CLARIFIER SOLIDS LOADING VS.
EFFLUENT SUSPENDED SOLIDS
-------
100 T
80 .
3H, 1L
A 3H
* (2H. 2L)
60 .
QC
LLJ
O
Q.
LU
C/J
OC
O
I
40 -
"2H
(1H.2L)
3L
(1L.1H)
,AlH,3L
(2H, 1L)
20 •
MIN. OPERATING HP
FOR MIXING
NOTE: L = LOW SPEED
H = HIGH SPEED
600
12,000
1,800 2,400 3,000
OXYGEN TRANSFERRED (LBS./DAY)
3,600
4,200
4,800
FIGURE 29
HORSEPOWER - OXYGEN TRANSFER RELATIONSHIPS
-------
An analysis of the sludge wasted to the digester was made, using information obtained
from the literature and concepts discussed by Loehr [18]. Figure 30 shows the calculated
composition of the waste sludge solids. The solids lost from the system per day consisted
of an average of 950 pounds pumped to the digester and 220 pounds in the effluent, for
a total of 1170 pounds per day.
A large portion of the influent TSS is carried through the system as residual,
nondegradable, solids. These residual solids consisted of all the inert solids plus that
portion of the volatile solids which were nondegradable.
The nondegradable influent volatile solids were assumed to constitute 40 percent of the
influent VSS, as suggested by Eckenfelder [15].
The remainder of the solids wasted to the digester (387 Ib/day) were biological solids.
The biological solids were also broken down into three classifications: inert,
nondegradable volatile, and degradable volatile. The fraction of each type depends on two
important operating parameters: sludge age and temperature. Analysis of data presented
by Eckenfelder [20] and McKinney [3] indicates that, at 15.7 degrees C and a sludge
age of 19.5 days, biological solids will be about 77 percent volatile. Determination of the
degradable and nondegradable portions of the biological volatile solids was based on data
presented by McCarty and Brodersen [10]. The biological volatile solids were estimated
to be about 60 percent degradable at a temperature of 15.7 degrees C and assuming a
19.5 day sludge age.
This analysis shows that there is a maximum percentage of the total waste solids that are
degradable for a particular set of operating conditions. For the average operating
conditions encountered during this study, the maximum degradable portion of the waste
solids was calculated to be about 19 percent.
This low percentage of degradable solids is partially due to the relatively high proportion
of influent suspended solids to waste activated sludge solids in the sludge wasted to the
digester. The long sludge age of the system is also partially responsible for this condition,
since the biological solids are already highly degraded before being wasted to the digester.
The items discussed in the preceding paragraphs serve to explain the low percentage of
reduction in volatile content through the digester. The reduction in volatile content
should increase in the future, as digester biological solids loading increases and the sludge
age decreases.
DETENTION TIME—The minimum digester detention time occurring during the
demonstration period was about 35 days. A plot of VSS content of the digested sludge
vs. digester detention time showed highly scattered data with no reasonable trends.
-72-
-------
INERT
RESIDUAL
INFLUENT
SOLIDS
VOLATILE
NONDEGRADABLE
BIOLOGICAL
SOLIDS
DEGRADABLE
VOLATILE
NONDEGRADABLE
\
INERT
i
*£.<$>.•$
;*', *'.^V
TOTAL SOLIDS WASTED/DAY (AVG.)
260 LBS./DAY
303 LBS./DAY
179 LBS./DAY
118 LBS./DAY
90 LBS./DAY
950 LBS./DAY
FIGURE 30
COMPOSITION OF WASTE SLUDGE SOLIDS
73-
-------
Lawton and Norman [19] have shown that very little volatile solids reduction occurs at
detention times greater than about 15 days. Since the minimum detention time recorded
during this study period was 35 days, all the data lay in the range of low activity. Thus,
the data scatter is a result of variations in testing rather than differences in VSS
reduction.
SLUDGE YIELD-The following equation, giving the net accumulation of volatile
biological solids per pound of BOD removed, was presented in Section III:
A
T ' °'65 - i + E
bM
In this equation, the constant, 0.65, represents the sludge yield coefficient, a, for
domestic sewage and the constant, 0.53, is the yield coefficient based on synthesis of
degradable biological solids only. The term E/M is equal to the reciprocal of the sludge
age, Ts.
The net accumulation of volatile biological solids per pound of BOD removed was
calculated from field data as 0.425 Ib VSS per Ib BOD removed. The equation was
modified as follows, to enable the determination of the sludge yield coefficient, a, for
this system:
The constant 0.65 was replaced by the constant a.
The constant 0.53 was replaced by the constant 0.6a, which represents
the degradable fraction of the volatile bioligical solids as established
previously in this Section.
The term E/M was replaced by l/Tg.
These modifications resulted in the following expression for a:
A/F
" 06
a = 1
This equation yields an "a" value of 0.70 for a sludge age of 19.5 days and a "b" equal
to 0.1, which is in relatively close agreement with McCarty and Brodersen's a value of
0.65 for domestic sewage.
-74-
-------
CHLORINE CONTACT
The effluent total coliform count averaged about 41 per 100 ml with a maximum of 230
and a minimum of 2. A chlorine residual of about 1.0 ppm was maintained in the
effluent nearly all the time.
Studies were conducted, using Rhodamine B dye and a fluorometer, to determine the
actual detention time in the chlorine contact channel. These tests indicated that the
actual detention time was about 83 percent of the theoretical detention time, based on
the time of peak dye concentration. The efficiency could likely be increased substantially
by the addition of an inlet baffling system. However, the coliform data has been well
within the required standards, indicating that the channel has provided effective contact
time.
-75
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SECTION X
ACKNOWLEDGMENTS
This project was supported in part by Environmental Protection Agency Research and
Development Grant No. 11060 EZR. Appreciation is expressed to the administration and
staff of the City of Dallas, Oregon, the EPA Pacific Northwest Water Laboratory
personnel, and Cornell, Rowland, Hayes & Merryfield staff members for their cooperation
and assistance during this study.
77-
-------
SECTION XI
REFERENCES
1. "Glossary: Water and Wastewater Control Engineering," APHA, ASCE,
AWWA, WPCF, (1969).
2. Hawkes, H.A., Ecology of Waste Water Treatment, Pergamon Press, New York,
N.Y. (1963).
3. McKinney, R.E., Microbiology for Sanitary Engineers, McGraw-Hill Book Co.,
New York, N.Y. (1962).
4. Weston, R.F., and Eckenfelder, W.W., "Application of Biological Treatment to
Industrial Wastes, I. Kinetics and Equilibria of Oxidative Treatment." Sewage
and Industrial Wastes, 27, 802 (1955).
5. McKinney, R.E., "Biological Design of Waste Treatment Plants." Presented at
Kansas City Section of ASCE Seminar, Kansas City, Mo. (1961).
6. McKinney, R.E., "Mathematics of Complete Mixing Activated Sludge." Jour.
San. Engr. Div., Proc. Amer. Soc. Civil Engr., 88, SA3, 87 (May 1962).
7. Eckenfelder, W.W., "Comparative Biological Waste Treatment Design." Jour.
San. Engr. Div., Proc. Amer. Soc. Civil Engr., 93, SA6, 157 (December 1967).
8. Lawrence, A.W., and McCarty, P.L., "Unified Basis for Biological Treatment
Design and Operation." Jour. San. Engr. Div., Proc. Amer. Soc. Civil Engr., 96,
SA3, 757 (June 1970).
9. Eckenfelder, W.W., "A Theory of Activated Sludge Design for Sewage."
Proceedings of Seminar at the University of Michigan, 72 (February 1966).
10. McCarty, P.L., and Brodersen, C.F., "A Theory of Extended Aeration
Activated Sludge.", Jour. Water Poll. Control Fed., 34, 1095 (1962).
11. Standard Methods For the Examination of Water and Wastewater, APHA,
AWWA, WPCF, New York, N.Y. (1965).
79-
-------
12. FWPCA Methods For Chemical Analysis of Water and Wastes. Federal Water
Pollution Control Federation (1969).
13. Smith, R., "Cost of Conventional and Advanced Treatment of Wastewater."
Jour. Water Poll. Control Fed., 40, 1546 (1968).
14. Michel, R.L., "Costs and Manpower For Municipal Wastewater Treatment Plant
Operation and Maintenance, 1965-68," Jour. Water Poll. Control Fed., 42,
1883 (1970).
15. Eckenfelder, W.W., "Volume 1 - Manual of Treatment Processes."
Environmental Science Services Corp. (1968).
16. Snokist Growers, Inc., "Aerobic Treatment of Fruit Processing Wastes." Report
No. DAST-8, U.S. Dept. of Interior, Fed. Water Quality Admin. (1969).
17. French, The R.T. Company, "Aerobic Secondary Treatment of Potato
Processing Wastes." Environmental Protection Agency, Water Quality Office
~ (1971).
18. Loehr, R.C., "Aerobic Digestion: Factors Affecting Design." Water and
Sewage Works, R170 (1969).
19. Lawton, G.W., and Norman, J.D., "Aerobic Sludge Digestion Studies." Jour.
Water Poll. Control Fed., 36, 495 (1964).
20. Eckenfelder, W.W., and Ford, D.L., "Laboratory and Design Procedures For
Wastewater Treatment Processes." The Center For Research in Water Resources
at the University of Texas at Austin; Austin, Texas (1968).
80
-------
SECTION XII
PUBLICATIONS
Graham, J.L. and Filbert, J.W., "Combined Treatment of Domestic and Industrial Wastes
By Activated Sludge." Proceedings, First National Symposium on Food Processing Wastes,
Sponsored By: FWQA Pacific Northwest Water Laboratory; USDA Western Regional
Research Laboratory; National Canners Association; and Northwest Food Processors
Association, Portland, Oregon (1970).
Graham, J.L. and Filbert, J.W., "An Unconventional Approach," The American City,
October 1970.
-81 -
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SECTION XIII
ABBREVIATIONS
mg/1 Milligrams per liter
BOD Biochemical Oxygen demand
MLSS Mixed liquor suspended solids
MLVSS Mixed liquor volatile suspended solids
mgd Million gallons per day
TSS Total suspended solids
VSS Volatile suspended solids
SVI Sludge volume index
D.O. Dissolved oxygen
O2 Oxygen
Ts Sludge age
-83-
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SECTION XIV
APPENDIXES
NO. PAGE
A Photographs 87
B Process and Laboratory Equipment 95
C Velocity and Dissolved Oxygen Data 99
D Costs 115
E Results of PVC Tests 119
-85
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APPENDIX A
PHOTOGRAPHS
-87-
-------
00
OC
FIGURE A-1
CLARIFIER & CONTROL BUILDING
-------
FIGURE A-2
AERATION BASINS
-------
FIGURE A-3
AEROBIC DIGESTER
-------
FIGURE A-4
-------
FIGURE A-5
SOLIDS DEPOSITS - AERATION BASIN NO. 1, N. SIDE
FIGURE A-6
SOLIDS DEPOSITS AND SCOUR-AERATION BASIN NO. 1
-92-
-------
FIGURE A-7
DRIED HUMUS (2'x3' AREA)
FIGURE A-8
AERATION BASIN NO. 1
-93-
-------
APPENDIX B
PROCESS AND LABORATORY EQUIPMENT
-95-
-------
PROCESS EQUIPMENT
EQUIPMENT
Comminutor
Sludge Recirculation Pumps
Raw Waste Pumps
Aerators
Clarifier
Chlorination Equipment
Flowmeters
Flowrecorder
Sampler
Waste Sludge Pumps
Sample Pumps
Chlorinator Water Supply
Nonpotable Water Pumps
Air Compressor
MODEL
25A
6FNJD-15
6FNC-15
Model 25
Model 30
RSR Type
V-800 Chlorinator
Propeller Type
260-B
T4A3B
FS-22
PACO 1070-1
PACO 1270-5
MANUFACTURER
Worthington Corp.
Eimco Corp.
Dorr-Oliver, Inc.
Wallace & Tiernan
Hersey-Sparling Meter Co.
Gorman-Rupp Co.
Robbins and Meyers
Moyno Pump Division
Pacific Pumping Co.
Bell & Gossett Products
-96-
-------
LABORATORY EQUIPMENT
EQUIPMENT
Furnace
Drying Oven
Magnetic Stirrer
pH Meter
Demineralizer
D. 0. Meter
Balance
TYPE
Thermolyne Type 1400
Precision Scientific
VW & R Magnistir
Photovolt
Barnstead Bantam
YSI Model 54
Voland & Sons
Model 220D
RANGE
0-1400°C
0-140°C
0- 10gal/hr.
0 - 20 ppm
0 - 200 g
-97
-------
APPENDIX C
VELOCITY AND DISSOLVED OXYGEN DATA
-99-
-------
DEPTH OF READINGS 1 FOOT
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE C-1
AERATION BASIN VELOCITY PROFILE
FOUR AERATORS - LOW SPEED
I 00-
-------
DEPTH OF READINGS: 6 FEET
c
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE C-2
AERATION BASIN VELOCITY PROFILE
FOUR AERATORS - LOW SPEED
101
-------
DEPTH OF READINGS: 9 FEET
c
ROTATION OF AERATORS
IN OPERATION
VELOCITIES IN FEET PER SECOND
FIGURE C-3
AERATION BASIN VELOCITY PROFILE
FOUR AERATORS - LOW SPEED
- 102
-------
DEPTH OF READINGS: 1 FOOT
c
ROTATION OF AERATORS
IN OPERATION
D.O. IN MG/L
FIGURE C-4
AERATION BASIN D.O. PROFILE
FOUR AERATORS - LOW SPEED
-I 03-
-------
DEPTH OF READINGS: 6 FEET
c
ROTATION OF AERATORS
IN OPERATION
D.O. IN MG/L
FIGURE C-5
AERATION BASIN D.O. PROFILE
FOUR AERATORS - LOW SPEED
-104-
-------
DEPTH OF READINGS: 9 FEET
r>
ROTATION OF AERATORS
IN OPERATION
D.O. IN MG/L
FIGURE C-6
AERATION BASIN D.O. PROFILE
FOUR AERATORS - LOW SPEED
105
-------
6-
Q
01
CO
X
o
Q
LU
uj 2.
Q
do
dt
5.6mg/l/HR.
D.O. UPTAKE = 0.013 mg Oj/mg VSS/d
DATE:
TIME:
TEMP.:
20
OCT. 16, 1970
10:00 A.M.
40 60
TIME (MINUTES)
TSS = 15,000 mg/l
VSS = 10,000
80
100
FIGURE C-7
DISSOLVED OXYGEN DATA
DIGESTER
- 106 -
-------
6-
4-
D
LU
to
=>
X
o
Q
LU
uj 2-
Q
do
dt~
= 4.5 mg/l/HR.
D.O. UPTAKE 0.011 mg 02/mg VSS/d
DATE:
TIME:
TEMP.:
20
OCT. 16, 1970
1:15 P.M.
40 60
TIME (MINUTES)
TSS = 15,000 mg/l
VSS = 10,000 mg/l
80
100
FIGURE C-8
DISSOLVED OXYGEN DATA
DIGESTER
!07
-------
Q
LU
in
LU
13 4-
X
o
_
8
H; 2-
D
do
-r- = 7.5 mg/l/HR.
dt
D.O. UPTAKE 1.03 mg 02/mg VSS/d
20
40 60
TIME (MINUTES)
80
100
DATE:
TIME:
TEMP:
OCT. 14, 1970
11:30 AM
TSS
VSS
630 mg/l
175 mg/l
FIGURE C-9
OXYGEN UPTAKE DATA
AERATION BASIN
- 108-
-------
O
LU
C/3
=>
X
o
Q
6-
4-
2 -
do
—— = 5.5 mg/l/HR.
D.O. UPTAKE = 0.155 mg02/mg VSS/d
DATE:
TIME:
TEMP.:
20
OCT. 15, 1970
9:30 A.M.
40 60
TIME (MINUTES)
TSS = 1360 mg/l
VSS 850 mg/l
80
100
FIGURE C-10
DISSOLVED OXYGEN DATA
AERATION BASIN
109-
-------
6-
4-
Q
LU
to
z
LU
d
X
o
Q
LU
O
C/J
OT 2-
Q
— 6.55 mg/l/HR.
at
D.O. UPTAKE 0.16mg02/mg VSS/d
20
40
I
60
80
100
TIME (MINUTES)
DATE:
TIME:
TEMP.
OCT. 15, 1970
11:00 A.M.
TSS 1240 mg/l
VSS 990
FIGURE C-11
DISSOLVED OXYGEN DATA
AERATION BASIN
MO-
-------
6-
4_
Q
LJJ
CO
X
o
Q
LLJ
O
to
55 2.
Q
do
dt - 6.70 mg/l/HR.
D.O. UPTAKE 0.28 mg 02/mg VSS/d
DATE:
TIME:
20
OCT. 15, 1970
1:45 P.M.
40 60
TIME (MINUTES)
TSS 850 mg/l
VSS = 570 mg/l
80
100
TEMP.: 17.5 C
FIGURE C-12
DISSOLVED OXYGEN DATA
AERATION BASIN
-------
6-
Q
01
in
01
13 4-
X
o
Q
LLJ
o
!>•
--= 5.69 mg/l/HR.
dt
D.O. UPTAKE 0.21 mg Oj/mg VSS/d
20
40 60
TIME (MINUTES)
100
DATE:
TIME:
TEMP:
OCT. 14, 1970
4:00 P.M.
19°C
TSS
VSS
= 860 mg/l
660 mg/l
FIGURE C-13
DISSOLVED OXYGEN DATA
AERATION BASIN
-------
8-1
_J 6-
Q
LLJ
4-
X
o
Q
I.
do
= 6.45 mg/l/HR.
dt
D.O. UPTAKE = 0.76 mg 02/mg VSS/d
20
40 60
TIME (MINUTES)
80
100
DATE:
TIME:
TEMP.:
OCT. 14, 1970
1:30 P.M.
TSS 680 mg/l
VSS= 205 mg/l
FIGURE C-14
OXYGEN UPTAKE DATA
AERATION BASIN
H3-
-------
APPENDIX D
COSTS
- 115
-------
TABLE D-1
CITY OF DALLAS, OREGON
WATER POLLUTION CONTROL PLANT
CONSTRUCTION COSTS
ITEM TOTAL COST
Temporary Facilities $ 12,000
Bond and Insurance 8,000
Move-In and Site Preparation 20,000
Cleanup and Finish Grading 2,000
Earthwork 7,000
Headworks 4,000
Aeration Basin Splitter Box 3,500
Aeration Basins 83,000
Clarifier and Sludge Recirculation Pump Station 40,600
Aerobic Digester 19,600
Flow Measurement Box 600
Chlorine Contact Channel 12,500
Humus Ponds 8,000
Control Building 23,000
Maintenance and Storage Building 1,500
A.C. Road and Parking 7,250
Gravel Road and Parking 2,000
Concrete Walks and Curbs 1,800
Fencing 7,000
Painting 6,000
Outside Piping and Plumbing 30,500
Sewage Shredder 10,000
Aeration Equipment 81,000
Clarifier Mechanism 17,500
Sludge Recirculation Pumps 9,500
Self Priming Sludge Pumps 2,150
Flow Measurement Equipment 4,000
Chlorination Equipment 6,100
Miscellaneous Pumps and Sampler 2,000
Hoisting Equipment 2,500
Laboratory Equipment and Furnishings 3,000
Electrical 21,000
Raw Sewage Pump Station 73,000
116
-------
TABLE D-1 - Continued
ITEM TOTAL COST
Plans and Specifications $ 31,480
Test Borings 400
Supervision and Inspection of Construction 20,910
Administrative, Legal and Fiscal Costs 1,080
Land 20,000
TOTAL $605,470
117-
-------
TABLE D-2
DEMONSTRATION, OPERATION AND
MAINTENANCE COSTS
OPERATION AND DEMONSTRATION
ITEM MAINTENANCE COSTS COSTS
Labor $11,460.87
Electrical Power 6,395.72
Chemicals 2,153.39
Maintenance 956.99
Miscellaneous (Supplies, etc.) 1,225.26
Post Construction Studies
and Reports $ 8,319.91
Legal and Fiscal Costs 506.45
Administrative Costs 1,679.19
TOTALS $22,192.23 $10,505.55
Total Cost First Year Demonstration $32,697.78
-------
APPENDIX E
RESULTS OF PVC TESTS
-119-
-------
OREGON STATE UNIVERSITY CORVALUS. OREGON
SCHOOL OF ENGINEERING Reply to: DEPARTMENT OF
GENERAL ENGINEERING
December 8, 1970
Mr. Robert Burm, Staff Engineer
National Waste Treatment Research Program
Pacific Northwest Water Laboratory
200 S.W. 35th St.
Corvallis, Oregon 97330
Dear Mr. Burm:
Following are my interpretations of the test results on the PVC
liner. I have assumed that the used material (A) was the same as the
20 mi 1 new material (B) initially.
There is evidently some loss in material over the one year use
as a sewage pond liner. The chemical action, however, is apparently
not detrimental to the properties. All measured properties show an
increase in resistance to load: approximotely 10% increase in tensile
strength and secant modulus and about 20% increase in tear resistance.
The percent elongation at break shows about a 20% increase, also. The
Change in all these factors can be conveniently expressed as a signi-
ficant increase in toughness .
The one other significant result is related to the standard
deviations. The standard deviations of both the new samples are
essentially the same while those of the used sample are approximately
50% to 200?o larger than those of the new samples. As could have been
foreseen, this indicates that the effect of the chemical environment
Is quite variable even though the trend in change is as indicated in
the previous paragraph.
One would expect to approach optimum use time after which the
properties as measured in these tests would begin to decrease and at
some later time come back to the original values and thence decrease
further. The determination of the regression time to original values
is important as it may be anywhere from relatively short to quite long.
Ultimately, the material may fail as a result of extreme thinning (with
the occurance of holes) before decreased strength values leading to
fai 1 ure occur .
If you should require any further assistance, please feel free to
cal 1 upon me .
Yours truly,
David A. Bucy
Associate Prof.
120-
-------
.// ^H I
CORVALLIS. OREGON 97331 gj
December 1, 1970
OREGON STATE UNIVERSITY
DEPARTMENT OF
METALLURGICAL ENGINEERING
Mr. Robert Burm, Staff Engineer
National Waste Treatment Research Program
Pacific Northwest Water Laboratory
200 S.W. 35th St.
Corvallis, Oregon 97330
Dear Mr. Burm:
Enclosed are the results of the tests you requested on the three samples of
plastic liner. Also included is a detailed procedure followed during testing.
As discussed by telephone on October 20, 1970, the results of these tests are
mutually comparable and should be comparable to further tests conducted
following the outlined procedure. The tear test results are not necessarily
comparable to tests conducted following ASTM D1004 because of the lack of a
.-!t*a for cutting the samples. Other than the lack of a die, the tests were
conducted following ASTM D882 and ASTM D100*».
If you should require any further assistance, please feel free to call upon me.
Yours truly,
David A. Bucy
Associate Professor
DAB:jaw
- 121 -
-------
SUMMARY OF TESTS
Gage Length (Tensile)
Nominal Width, in.
Nominal Thickness, in.
Break Factor, Ib/in.
S
Tensile Strength, psl .
S
% Elongation at Break
S
Secant Modulus of Elasticity,
AL = 3 in., psi
Tear Load, Ib
S
A
5
1
0.0195
40.5
2.2
2090
no
238
31
1760
55
7.88
0.7**
B
5
1
0.0209
40.2
1.1
1920
48
195
9-7
1600
38
6.51
0.41
C
5
0.5
0.0299
64.5
1.4
2170
43
304
10
1290
35
9.15
0.66
A - used 20 mi 1 PVC
B - new 20 mi 1 PVC
C - new 30 mi 1 PVC
-------
PLASTIC SHEETING TEST REPORT
FOR: Mr. Robert Burn, Pacific Northwest Water Laboratory
BY: David A. Bucy, P.E., State of Oregon^Department of
Metallurgical Engineering, Oregon State University
Procedures for Testing Plastic Sheeting
Tensile Properties Test
ASTM D882 (copy appended) was followed. Report
proper includes all pertinent information.
Tear Resistance Test
ASTM D100A (.copy appended) was followed except for
the die described under paragraph 3-(e). Samples
were cut through a mimeographed copy of the shape
attached to the material using a razor blade.
Particular attention was paid to the 90° notch to
ensure no over cut occurred.
123-
-------
TENSILE PROPERTIES OF THIN PLASTIC SHEETING
1. Material
Three lots of material were supplied by Robert Burm, Pacific Northwest
Water Laboratory and will be designated A,B, and C as follows:
A. Used plastic liner. Apparently, from cutting, density, and burn
test, it is polyvinyl chloride (PVC). Assumed to be isotropic in
plane of sheet." Six strips approximately 3 inches by 20 inches.
B. New sheet approximately 13 inches by 32 inches. Marked "20 mil
thickness, PVC" by R. Burm. Thought to be identical with A but
unused. Cutting, density, and burn test results same as A (PVC).
C. New sheet approximately 17 inches by 29 inches. Thicker than A
and B. Cutting, density, and burn test results same as A and B
(PVC). Assumed to be isotropic in plane of sheet."
2. Preparation of Test Specimens
Test specimens were cut with a razor blade moved along a straight edge
guide. Specimen edges were inspected microscopically to detect nicks
or tears.
3. Specimen Dimensions (Nominal)
Material Thickness Width. Length
A 0.0195 in. 1.0 in. 7.0 tn.
B 0.0209 in. 1.0 in. . 7.0 in.
C 0.0299 in. £3 in/1^ 7.0 in.
* All sample pieces are too small to identify original roll transverse
and longitudinal directions.
124-
-------
Tensile Properties of Thin Plastic Sheeting Cont.
Page Two
A. Number of specimens
Six specimens of each material were tested.
5. Strain rate - 0.1 in./in./min. was used in order to meet requirement for
Modulus of Elasticity measurement.
6, Initial grip separation - 5 inches.
7. Crosshead soeed - 0.5 in./min.
9. Gr?p s - rubber faced approximately 1 inch x 1 inch square as supplied by
Instron.
TO. Test method - A
11. Conditioning
Temperature - 70°F
Relative Humidity -
12. Anomalous behavior - Tear in one specimen,
125-
-------
Accession Number
Subject Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Dallas, Oregon, City of
Title
Combined Treatment of Domestic and Industrial Wastes
By Activated Sludqe
10
Authors)
Dallas, Oregon,
City of
16
Project Designation
Grant ftp. -~.L213ffiBZR (11060 EZR)
21
Note
22
Citation
Descriptors (Starred First)
*Waste treatment, *Aerobic treatment, Industrial wastes,
Activated Sludae, Domestic Wastes
25
Identifiers (Starred First)
*Food processing wastes, Aerobic digestion, Treatment costs.
27
Abstract
The operation of a completely aerobic secondary treatment facility for treatment of combined domestic and industrial wastevvater
from the City of Dallas, Oregon, was studied for a period of 15 months. The system was designed for an average daily flow of 2.0
mgd and a BOD load of 7000 pounds per day. The results of this study indicate the flexibility and economy of the completely
aerobic system, consisting of activated sludge with aerobic digestion, for a small community with proportionately high industrial
wastewater loads. The effluent BOD concentration averaged 8 mg/1 and the effluent total suspended solids concentration averaged 13
mg/1 for the 15-month study period. The biological solids yield averaged about 0.7 pounds of solids per pound of BOD removed and
the net accumulation of biological volatile solids was about 0.42 pounds of volatile solids per pound of BOD removed. These values
were obtained with a MLSS concentration range of 700 to 3000 mg/1, an average sludge age of 19 days and an organic loading range
of 0.05 to 0.40 pounds of BOD per pound of MLSS per day. Total capital cost of the system was about 66 percent of that for a
conventional activated sludge plant and operation and maintenance costs were only about 33 percent of those for a conventional
system.
This report was submitted in fulfillment of Grant No. 11060 EZR under the partial sponsorship of the Water Quality Office,
Environmental Protection Agency.
Abstractor
John L. Graham
Institution
Cornell, Rowland, riayes & Merryfield, Corvallis, Ore
WR:102 (REV. JULY <969)
WRSI C
SEND TO: WATER RESOURCES SCIENTIFIC INFORMATION C EN
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
* CPO: 1563-359-33?
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