I'll
.ENVIRONMENTAL PROTECTION AGENCY
ROCKY MOUNTAIN-PRAIRIE REGION
REGION VIII
TECHNICAL ASSISTANCE
PROJECT
Evanston MWWTP Facility
Evanston Wyoming
OPERATION a
WATER
JUNE 1976
MAINTENANCE
DIVISION
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4" {
OlbL
6,1
REPORT ON THE
TECHNICAL ASSISTANCE PROJECT
AT THE
EVANSTON WASTEWATER TREATMENT PLANT
EVANSTON, WYOMING
DECEMBER 1975 - FEBRUARY 1976
George Hartmann, Project Engineer
Control Technology Branch
Water Division
Environmental Protection Agency
Region VIII
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TABLE OF CONTENTS
Page No.
I. INTRODUCTION 1
II. SUMMARY AND CONCLUSIONS 3
III. RECOMMENDATIONS 5
IV. DESCRIPTION OF PLANT 8
A. HISTORICAL 8
B. PLANT UNITS AND PROCESSES 9
V. DISCUSSION OF ASSISTANCE PROJECT 11
A. INITIAL PLANT INSPECTION 11
B. INITIAL PLANT OPERATION IMPROVEMENTS 13
C. CONTROL TESTING 15
D. OPERATOR TRAINING AND PLANT EVALUATION.... 16
APPENDIX: 0 & M INSPECTION REPORT OF
FEBRUARY 3, 1976 19
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I. INTRODUCTION
The Evanston, Wyoming municipal wastewater treatment nlant (MWWTP)
had been found to be operating without an NPDES discharge permit in
early 1974 and was issued its permit in July 1974. Subsequent
compliance monitoring visits by the State of Wyoming and the Region
VIII office indicated the facility was bypassing raw sewage and was
not exercising good operation of the facility.
The City, when it became aware of the technical assistance
program of the Region VIII EPA office, requested such assistance in
August 1975. Before assistance was given, the State of Wyoming
issued a cease and desist order to the City ordering the City to cease
bypassing the facility. The City responded that it was unable to
do so because the facility was hydraulically overloaded.
As a result of the technical assistance request, a preliminary
joint visit to the plant was made by the EPA and State of Wyoming
Department of Environmental Quality on December 2, 1975. Recommendations
were given to the City for investigating possible plant hydraulic
bottlenecks and for improving the plant operation. Continued communi-
cation and discussion with the City resulted in the elimination of
the bypass and improvements in plant operation by January 6, 1976.
Subsequently EPA and Wyoming D.E.Q. personnel returned to the
facility in early February 1976 to give additional help to the
operator and the City on improving the plant operation and maintenance
program.
1
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The purpose of this report is to document the findings of the
technical assistance project, including discussions of plant design,
operational controls and recommendations to the City for improving
plant operations.
2
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II. SUMMARY AND CONCLUSIONS
Little could be done to improve effluent quality at the time
of the on-site evaluation due to the limited time spent at the
facility. Although the effluent appeared to be of very good quality,
it was found that due to the lack of knowledge of operation and
lack of controls, that effluent quality would deteriorate durinq times
of too high aeration basin solids and too little aeration basin solids.
The operator was taught the proper methods of operation and conditions
which exist in the system. Although controls which are necessary to
fine tune the system are not available, it is felt that the"assistance
and training provided to the operator is sufficient at present for the
operator to maintain a good plant effluent unless flows become excessive.
Conversations with the plant operator and City Engineer since
February 6, 1975 indicate that the effluent quality of the plant is
still very good. A Wyoming D.E.Q. compliance monitoring sample
taken on February 22, 1976 found the plant effluent quality to be:
BOD5 - 3 mg/1
SS - 11 mg/1
F.C. - 6,200/100 ml
A continuing area of concern to the City is the problem of high
flows from infiltration during the spring and summer which could
still prove to be greater than the plant can hydraulically handle.
Because of this it may still prove necessary for the City to bypass
a portion of its flow during these high flow periods, however all
bypassed flow should be capable of at least passing through the
aeration tank before a bypass is made.
3
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The elimination of bypassing is evidence of the City's efforts
to comply with the State of Wyoming's cease and desist order. The
improvement in plant operation and maintenance are further indications
of the City's efforts to operate and maintain the present facility
in a manner that will result in an effluent that will more than
meet the NPDES permit conditions. Continued concern and support
by the City of Evanston for the wastewater collection and treatment
system operation should ensure satisfactory future wastewater treatment
plant performance.
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III. RECOMMENDATIONS
(1) The chlorinator should be repaired and used as soon as possible.
Although revisions to the federal secondary treatment standards have recently
been proposed with respect to fecal coliform limitations, the Evanston
facility must still operate and maintain its chlorination facilities.
(2) The infiltration/inflow problem which had been responsible
for the plant's hydraulic overload should continue to be studied to
determine the best way to alleviate this problem. If it becomes
necessary to bypass a portion of the plant flow in the spring due
to extremely high flows from infiltration/inflow, the Wyoming D.E.Q.
should be contacted immediately. As much as possible all flow'should
be pumped into the plant for treatment and then bypassed if necessary
to eliminate discharge of raw sewage.
(3) The plant staffing at the time of the assistance was barely
adequate with one man responsible for plant operation and maintenance.
The City should endeavor to have another man available to work part
time at the plant for weekends, vacation time and other periods
when the present operator is not on duty during the week, or when
he requires additional help for major repair work. It is recommended
that 8 hour, 7 day a week operation be instituted at the plant as soon
as possible.
(4) The plant aia not nave an alternate power source or emergency
alarm system for power loss or equipment breakdowns. The City should
investigate the installation of an emergency power source in the
future and should install an alarm system at the plant as soon as possible.
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(5) During the technical assistance the operator was shown
how to use various process control tests to determine how to control
the plant operation. The list of minimum necessary lab equipment
to conduct these tests was given to the City Engineer at that time.
This equipment should be acquired as soon as possible for use by
the operator.
(6) The basic plant operation and maintenance had been improved
substantially since the visit to the facility on December 2, 1975
by the EPA. However in order to keep the facility in operation and
to conduct a good preventative maintenance program, adequate tools
are required and proper record keeping should be instituted. In
addition;the plant site should be graded and seeded or sodded to
improve the plant appearance. Good site maintenance eliminates some of
the problems encountered from weeds blowing into the clarifier and aeration
basin, and from mud and ice problems encountered during the winter and spring.
(7) The present plant sludge handling facilities appeared to
be marginal. It may be necessary for the City to haul waste liquid
sludge from the plant if the existing sludge drying beds are found
to be inadequate to process all the waste sludge. Because the waste
sludge which must be put on these beds is not stabilized, there may
be some odors at the plant when sludge is put on the beds. Because
this sludge has not been stabilized, the final disposal of this
sludge should be controlled to limit public access to the sludge
disposal area. An acceptable method of final disposal is to landfill
the sludge after removal from the drying beds.
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(8) In any plant expansion or modification of the existing
clarifier, sludge withdrawal, sludge return and sludge wastinq equipment
should be carefully evaluated for modifications to improve plant
operational control.
(9) the weir on the chlorine contact tank, which was originally
a primary clarifier, was submerged. This facilitates short-circuiting
in the unit and will result in inefficient usage of chlorine. The
existing weir should be raised to eliminate this submergence if possible.
If raising the existing weir will not eliminate this submerged weir
condition, then correction of this deficiency should be accomplished by
constructing a new weir.
(10) The attached 0 & M inspection report for the facility has
some additional recommendations that pertain to plant design, operation
and maintenance areas. These should receive prompt attention and
consideration.
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IV. DESCRIPTION OF PLANT
A. HISTORICAL
Evanston, Wyoming received a federal grant in 1969 to construct
secondary treatment facilities (extended aeration) at the existing
city primary wastewater treatment plant. The upgraded facility
went on line in 1970. At the same time the City conducted an
extensive sewer line sealing program to reduce the infiltration
rate in the city sewer system. When the plant initially went into
operation, the plant effectively treated all the wastes it received.
However, by 1974 the plant flow had increased due to high infiltration
flows again and the City was bypassing a portion of its flow
directly to the Bear River.
The City received its NPDES permit in July 1974 with a
monthly effluent limitation of 80 mg/1 because of the high flows to
the plant. In August 1975 an EPA Permit Compliance Monitoring team
found the plant was still bypassing and the State of Wyoming issued
an order to the City to stop bypassing.
The City of Evanston, after learning of the Technical Assistance
program of the Region VIII EPA Office, requested assistance to
see what the City could do to eliminate the bypassing. During the
latter part of the summer of 1975 the City replaced a section of
Interceptor that was responsible for a large amount of the infiltration
flow.
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B. PLANT UNITS AND PROCESSES
The Evanston, Wyoming wastewater treatment plant is a 1.8 mgd
activated sludge plant (extended aeration). Flow enters the plant
and passes through a comminutor and then through a parshall flume.
The sewage then enters a grit removal basin and then to a wet well'. Sewage
is pumped from the wet well to the aeration basin with earthen dikes along
with the return sludge. The mixed liquor leaves the aeration basin and
flows to the secondary clarifier. The scum floats to the water sur-
face and is scraped into a scum pit by surface skimming arms. The
scum is periodically pumped from the scum pit and returned to the
aeration basin. The heavy solids settle to the bottom of the second-
ary clarifier and are scraped into a pit and pumped from the pit into
the raw sewage line and returned to the aeration basin. The effluent
overflows the clarifier weirs and flows to another clarifier which is
being used for a chlorine contact tank. Treated wastewater then flows
from the chlorine contact tank to a ditch. The water in the ditch
eventually enters the Bear River.
The plant is also equipped with sludge drying beds. Sludge is
wasted to the drying beds by diverting return sludge flow from the
raw sewage line to the waste sludge line. Figure I is a schematic
flow diagram of the facility along with the sizes of the units.
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FIGURE I
TECHNICAL ASSISTANCE PROJECT
EVANSTON, WYOMING WASTEWATER TREATMENT FACILITY
Flow Diagram
December 1975 - February 1976
Legend
1
*
ro
%
CO
4
J
-~Sewage
-~-•-~Mixecl Liquor
o ^Return Sludge
"~Scum
/•/ A^Waste Activated Sludge
9 Pumps
1. Bar Screen & Comminutor
2. Parshall Flume & Flow Sensing Devi
3. Grit Removal System
4. Raw Sewage Wet Well
5. Control Building, Lab, Office and Pump
6. Aeration Basin
7. Final Clarifier
8. Chlorine Contact Tank
9. Sludge Drying Beds
10. Anaerobic Digester (Not in use)
11. Chlorine Building
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V. DISCUSSION OF ASSISTANCE PROJECT
A. INITIAL PLANT INSPECTION
On December 2, 1975 a joint EPA and State visit to the Evanston
WWTP was made to determine whether technical assistance could help the
City improve its plant operation. At that time the City was treating
approximately 80% of the flow, while the rest was being discharged
raw. The operator was unable to get all the flow through the plant
even though in December the infiltration rate was minimal due to low
groundwater conditions in December.
The plan^at the time of the inspection^had a number of major
operating problems because of past practices of inadequate operation
and maintenance. The operator at the plant had also been hired less
than a year ago and had no experience in WWTP operation. After a
careful review of the plant, the cause of the bypassing was determined
to be the inability of the transfer pipe between the aeration tank and
secondary clarifier to handle all flows through it. This flow limitation
caused the aeration basin liquid level to rise and submerge the
fixed surface mechanical aerators more than the design called for.
This resulted in the mechanical aerators automatically shutting down
because the aerator motors overheated when operating in a submerged
condition. During extremely high flows it was feared that if no bypassing
took place, the entire aeration basin would overflow the earthen basin dikes.
Other problems apparent at the time of the inspection were:
(1) The comminutor was out of service, but parts were on order.
(2) The grit chamber was full of grit which resulted in the influent
parshall flume being submerged.
(3) The wet well pumps were not cycling properly and the pumping
rate was limited to only one of the three available raw sewage pumps.
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(4) The return sludge pump was only being operated during the
eight hour 8-5 workday, and at that time was being run at 100%
recycle.
(5) The aeration basin was aerobic but the solids level appeared
extremely high and no sludge had been wasted since the new operator
had come on board in February 1975.
(6) No process control was being used to control the plant.
The only tests being run were weekly settleable solids tests by the
operator and monthly Influent and effluent permit monitortng tests by a
private laboratory.
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B. INITIAL PLANT OPERATION IMPROVEMENTS
After the inspection the City was informed that three things
should be done immediately to improve the plant operation.
(1) Run the return sludge pump continuously, but at less than
the maximum rate if possible.
(2) Fix the wet well pump cycling control system so that the
pumps could handle all the plant flow.
(3) Clean out the grit chamber and repair the corminutor
as soon as the comminutor parts were received.
The City took action and implemented recommendations #1 and #2
immediately. Recommendation #3 was accomplished by mid-January when
the comminutor parts arrived. These actions by the City were effective
in improving plant operations significantly.
A copy of the plant construction drawings were obtained and after
a hydraulic analysis of the plant piping system, it was determined
that the pipeline between the aeration tank and clarifier should
handle the flow the plant was receiving at that time.
The City was informed of this and was given the recommendation
to pump out the secondary clarifier and to check the problem line
for possible obstructions such as rocks or other foreign objects. The
City engineer, following this suggestion, determined that a valve
on this line that was buried which was believed to be open was
found instead to be partially closed. Upon opening this
valve completely it was found that the plant could now treat all
the flow and bypassing was eliminated on January 6, 1976.
The City still felt, however, that technical assistance from
the EPA and State of Wyoming D.E.Q. would be beneficial as the plant
13
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operator had not had any real training in operating the facility.
The City agreed that if assistance was given, that it would attempt
to implement any recommendations that were made by the assistance
team to improve plant operations.
The technical assistance project was then initiated on
February 2, 1976 by members of the EPA Region VIII Office in Denver
and the State operator/trainer, of the Wyoming D.E.Q.
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C. CONTROL TESTING
A series of process control tests were initiated during the
on-site federal assistance project. These control tests consisted of
dissolved oxygen tests, centrifuge tests, turbidity tests, settle-
ability tests, and sludge blanket depths. These tests were conducted
six times a day by the operator.
The dissolved oxygen meter was used to measure the oxygen concen-
tration of the mixed liquor in the aeration basins.
The centrifuge test was used to determine the solids concentration
of the mixed liquor and return sludge throughout the day.
Turbidity tests were conducted on the effluent from the final
clarifier to monitor effluent quality.
Settleability tests were conducted on the mixed liquor to monitor
and observe sludge characteristics.
Sludge blanket depth determinations were made to determine sludge
levels in the final clarifier.
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D. OPERATOR TRAINING AMD PLANT EVALUATION
During the evaluation of the facility the operator was taught
how to perform the process control tests. Limited amount of
information was given to the operator due to the length of the assist-
ance project. Very little time was allowed for in-depth interpret-
ations of the process control tests.
The operator was also taugnt now to calculate settled sludge concen-
trations from the settleometer tests and how to plot the results on
process control graphs. An acceptable operating range was also given
to the operator. Reading material concerning operation and process
control was also left with the operator. The operator was informed
of the importance of plotting the data on the graphs and observing
the changes in sludge quality and the quality of the plant effluent
in relation. Also it was recommended that the reading material be
carefully reviewed and if questions existed to contact EPA Region VIII
O&M staff for assistance.
The first day of the on-site federal assistance consisted of
evaluating plant records and getting familiar with plant equipment, per-
sonnel involved with plant operation, and establishing background information
on plant operating status.
Members of the city management were contacted and the purpose of
the EPA/state evaluation was explained. The conversations with the
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city management team appeared to be very successful. They were
interested in dealing with problems which the evaluation of the
wastewater treatment plant might reveal, and subsequently took
steps to implement recommendations made during the assistance
project.
Process control test results for the first day indicated a
lower return sludge flow was necessary. The plant was equipped
with two constant speed return sludge pumps, each rated at
450 gpm. No flow measurement devices were installed on the return
sludge line and the return sludge was discharged to the aeration
basin with the raw sewage below the surface so that no accurate
determination of the return flow was possible. The only feasible
means available for reducing the return sludge flow (RSF) rate
at the plant was to partially close the butterfly valve on the
discharge side of the pump. It was possible to reduce the RSF
rate by running a pump in an on/off mode, but this is not good
practice and is not feasible during the 16 hours when the operator
is not at the plant.
The only means available for determining the change in
return sludge flow was indirectly through observation of the
change in the return sludge concentration (RSC). The RSC sample
was obtained by taking a sample of the RSF at a sample valve
before the return sludge pump. This procedure was then recommended
and used for determining changes in RSF.
During the fourth day of the assistance it was found that
the sludge settling characteristics had improved drastically,
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although no real change had been made in operations. The ATC,
RSC and dissolved oxygen concentration remained approximately
the same throughout the project, but sludge quality had improved
drastically. The operator had taken some settling tests in a
1000 ml graduated cylinder prior to the assistance and this data
indicated that the plant was still in a start-up phase.
The operator stated that in December the return sludge pump
was turned off for three days to allow the sludge in the system
to concentrate in the final clarifier so that a concentrated
sludge could be wasted to the drying beds. This resulted in
most of the sludge being wasted from the system, leaving a very
low MLSS. It was explained to the operator that this method of
wasting a large amount of sludge at infrequent intervals often
resulted in the type of poor plant performance that the plant
had earlier experienced. The operator was instructed to waste
small amounts of sludge when necessary and to monitor the effect
of that wasting on the mixed liquor solids concentration in the
aeration tank. After determining the concentration of mixed liquor
after wasting, and the quality of sludge in the system, the operator
would then determine if additional wasting was still required.
Guidelines,to be used for determining the amount of sludge to
waste at any one time were left with the operator.
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ENVIRONMENTAL PROTECTION AGENCY
DATE OF INSPECTION
REPORT ON OPERATION AND MAINTENANCE
OF WASTEWATER TREATMENT PLANT
February 3, 1976
Porm Approved
oai/3 No. r>s-Knor.
A. GENERAL INFORMATION
1. PL AN I
(n.) NAME
Evanston MWWTP
(h.) OWNER it.) LOCATION
City of l.vanston, WY Evanston,
WY
2. TYPE OF PL ANT
Extended Aeration
3. PRO iECT NO.
C-560069
4. AVG. DESIGN FLOW
! .8
5. DESIGN POPULATION
EQUIVAL ENT
5,000
6. COLLECTION SYSTEM
7. DATE PRESENT PLANT BEGAN OPERATING
1970
8. STATE PERMIT NO.
WY-0020095
COMPINCD V SEPARATE
BO TH
9. IN THE SPACE PROVIDED BELOW. FURNISH A SIMPLIFIED FLOW DIAGRAM OR A WRITTEN DESCRIPTION OF THE PLANT UNITS IN
FLOW SEQUENCE.
See Attached Sketch
10. IDENTIFY RECEIVING WATERS
Bear River
It, IDENTIFY PERTINENT STREAM STANDARDS AND/OR USES OF THE RECEIVING WATERS
Class I stream (game fishery)
12. GIVE THE EFFLUENT STANDARDS AND/OR REQUIREMENTS FOR STATE OPERATING PERMIT
By July 1, 1977 30 mg/1 BOD5&SS, 200/100 ml fecal coliform, 0.1 mg/1 total chlorine
residual.
B. CURRENT PLANT LOADING
1. ANNUAL AVG DAILY FLOW RATE (mfid)
0.87
2. PLAK FLOW RATE (m|Sc0
3. POPULATION SERVED
5,400
DRY wr.ATHER
WET WEATHER
1.19
-
4. AN N U A1. AVG BOLij OF RAW SEWAGE (mfi/l)
147.5
5. ANNUAL AVG SUSPENDED SOLID OF RAW SEWAGE (m$/t)
138
6. PRINCIPAL TYPES OF INDUSTRIAL WASTE DISCHARGED TO
MUNICIPAL SYSTEM
None
7. POPULATION EQUIVALENT (HOD) OF INDUSTRIAL WASTES
N. A.
8. POPULATION EQUIVALENT (SS) OF INDUSTRIAL WASTES
9. VOLUME OF INDUSTRIAL WASTES (mfiit)
10. INFILTRATION PROBLEMS
Yes. Ongoing 201 study is determining amount and source of infiltration.
EPA Form 7500-5 (4-72) REPLACES FORM FWPCA-12 WHICH IS OBSOLETE.
19
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I'onn Ajifimrcd
0A1 li No. 158-R0035
C PLANT PERFORMANCE
1.
LABORATORv ANALYSIS (Total Plant)
(0) REPORTING PERIOD
FROM (Month, year)
October 1975*
TO (Month, year)
January 1975
MONTHLY ITEMS
(b)
ACTUAL PLANT
PERFORMANC E
DATA
(c)
PLANT
DESIGN
DATA
(d)
NPDES
PERMIT
REQUIREMENTS
PLANT
ACHIEVES
DESIGN
EFFICIENCY
(f)
PL AS
COMPL
WITH PE
REQUIRE
fc
T
1 ES
RMIT
MENTS
(e)
Y ES
NO
YES
NO
(1)
F LOW (mad)
(monthl y average)
0.87
(Since bypassi
ng stopped
1
(2)
PEAK FLOW (mgd)
(maximum day)
1/6/76.)
(3)
SETT L E AB LE SOLIDS
(monthly overage)
IN FLUENT (ml/ 1)
EFFLUENT (ml/ 1)
?. REMOVAL
(4)
SUSPENDED SOLIDS
(monthly average)
INFLUENT (mg/1)
133
EFFLUENT (mg/1)
16
REMOVAL
88
85
X*
(5)
BODg (monthly average)
INFLUENT (mg/ 1)
138
EFFLUENT^ mg/ 1) .
15
80/120
X *
% R EMOVAL
88
85
X*
(6)
DISSOLVED OXYGEN
(monf/i/v average)
EFFLUENT (mg/ I)
(7)
CHLORINE RESIDUAL
(monthly average)
EFFLUENT (mg/ 1)
0.25**
(8)
COLIFOHM (per 100 ml)
(juonf/i/) average)
TO r AL
6330
rt.CAL
2300
(9)
pll RANGE. EFFLUENT
MINIMUM
7.2
6.0
X
MAXIMUM
7.4
9.0
X
(10)
TOTAL PHOSPHORUS r.isP
(muiif/Wy average)
INFLUENT (mg/ 1)
)
EFFLUENT (mg/ I)
r, REMOVAL
(11)
TOTAL NITROGEN (as N)
(monthly average)
INFLUENT (mg/1)
EFFLUENT (mg/1)
REMO V AL
2. plant records *Effluent data does not include raw sewage bypass that was in effect
**P1ant not chlorinating since 11/75. ^ 1—1 „ until 1/6/7
ARC mAnT hlv operating r ecort>s filed with STATE AGENCY' [_X| VES 1 I NO
)
EPA Fom, 7500-5 (R«v. 1-74) PACE 2
REPLArFS P A r, r. PJA 7 «'1 wi'irn 13 o n s o i r. r P
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Form Apptn\ <>d
OMB No. 158*R0035
3. DOES PLANT HAVE ALTERNATE ELECTRIC POWER SOURCE'
[37JOUAL FEF.D ['J GENERATOR [)(]NONE
4. ADEQUATE ALARM SYSTEM FOR POWER OR EQUIPMENT
FAILURES? QvES CXl NO
5. EQUIPMENT PROGRAM
ADE QU AT E
INADEQUATE
6. IS PLANT EFFLUENT
BEING CHLORINATED'
nv es n°
7, DOES SEWAGE BY-PASS
PLANT IN WETWEATHER'
|"29 YES | | NO
(a.) ROUTINE MAINTr.NANCE SCHEDULES
X
(h.) nr.coRDS of maintenance.REPAirs a replcwt
X
(C.) SPARC PARTS INVENTORY
X
8. DOES SEWAGE BY.PASS
PLANT IN DRY
WEATHER'
~
cxi ves n n°
9. AGENCIES NOTIFIED OF EACH BYPASS
Wyoming Dept. of Env. Quality
10. BYPASS FREQUENCY
(Monthly)
1 1. AVG DURATION OF
BYPASS (lirs)
24
12. REASON FOR BYPASSING
See Item G-?
13. CAN BYPASS SEWAGE BE
CHLORINATED? ~ y ES [X] NO
14. DO SEWER OVERFLOWS OCCUR
UPSTREAM OF PLANT?
~ YES
CXI NO
15. ANY ODOR COMPLAINTS BEYOND PLANT PROPERTY? (If yes, explain)
Yes. In summer, but less this past year than in previous
years.
16. OBSERVED APPEARANCE OF EFFLUENT, RECEIVING STREAM OR DRAINAGE WAY
Effluent was only slightly turbid. Where effluent entered the receiving dtich it was
clean. However 200 feet below this point until main flow of Bear River was reached
sludge banks 6-12" deep were found. See attached photos.
17. IS A CONSULTING ENGINEER RETAINED OR AVAILABLE FOR CONSULTATION ON OPERATING AND MAINTENANCE PROBLEMS'
[XYF.S [~| NO (7/ yes, check one of the loll owing) QX) CONTINUING PASES \ ~) REQUEST OASES
16. DO OPERATORS AND OTHER PERSONNEL ROUTINELY ATTEND SHORT
COURSES, SCHOOL OR OTHER TRAINING' ()£] YES [~] NO
(n.) H yc s, cilo course sponsor, and dale of Inst course.
Wyoming Operators School - October 1975
(b.) If no, tire there ony courses nvnilablc In this orcn5
(c.) Is there .in established procedure for training new operHtors3
Not yet.
19. IS LAB TESTJNG ADEQUATE FOR THE CONTROL
REQUIRED FOR THIS SIZE AND TYPE OF PLANT
AND USES OF RECEIVING WATERS'
~ YES Q5 NO (tf No, explain)
No process control
6-2.
See item
20. EXPLAIN MAIN DIFFICULTY EXPERIENCED WITH INDUSTRIAL WASTES
N.A.
21. PERMANENT RECORD FILE
(n.) PLANT OPERATION AND MAINTENANCE MANUAL' [ ] YES [X) NO (b.) AS BUILT PLANS AND SPECIFICATIONS' [0$ YES ~ NO
(c.) M AN U F AC TU R ERS OP E R ATION & MAINTENANCE SPECIFICATIONS7 Q Y ES [_X] NO Id.) FLOW CHARTS' ~ YES Q NO
22. ESTIMATED WEEKLY MAN-HOURS FOR LAB WORK INCLUDING MAINTENANCE OF RECORDS AND PREPARATION OF REPORTS
7
23. ANNUAL BUDGET FOR MAINTAINING AND OPERATING PLANT
SALARIES ft WAGES ELECTRICITY CHEMICALS MAINTENANCE STAFFING ft TRAINING OTHER
9,000
9,000
nx
300
2,600
7,260
15:000
46.160
24. STABILIZATION PONDS
(a.) WEEDS CUT AND VEGETATION GBOWTH IN PONDS REMOVED'
~ YES ~ NO
(b.) BANKS AND DIKES MAINTAINED? (Erosion, etc.)
~ YES ~ NO
(c.) ANY REPORTS OF GROUND WATER CONTAMINATION FROM POND' (It yen, give details) ~ YES ~ NO
(d.) SEEPAGE REPORTED
~ yes nN°
(e.) ADEQUATE DEPTH CONTROL7
~ yes ~ NO
(f.) EFFLUENT RELEASE IS
~ CONTINUOUS ~INTERMITTENT ~seasonal
epa Form7500-5 (4-72) page 3 *Bypassing stopped 1/6/76
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bortn Appmvcu
OMB No. 158-R0035
D. LABORATORY CONTROL
CODING INSTRUCTION
Enter test codes opposite appropriate items If any of the below tests are used to monitor industrial wastes, place an "X" in
addition to the test code.
1 - 7 or more per week 3 - 1, 2 or 3 per week 5 - 2 or 3 per month 7 - Quarterly 9 - Annually
2*4, 5 or 6 per week 4 - as required 6-1 per month 8 - Semi-Annually
ITEM
(».)
RAW
(t>.)
PRIMARY
EFFLUENT
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OW« No. ISIS'KUO.13
F. GUIDE - VISUAL OBSERVATION - UNIT PROCESS
RATING CODES. S Satisfactory; U - Unsatisfactory; M - Marginal; IN In Operation; OUT - Out of Operation
CONDITION Of* APPEARANCE
RATING
COMMEN TS
G NO UN PS
M
Needs soddinq or seedinq.
nun. nines
S
J
poTAiiLr. wa rr.n supply phot
S
tr
SAT LTV FEATURES
M
z
UJ
DYP ASSES
M
Automatic when flow exceeds Dlant capacity.
o
STO RM WATER OVERFLOWS
-
MAINTENANCE OF COLLCCTION SYSTEMS
M
PUMP STATION
M
Bubbler control for pumps r.onnprtpd to DumD
VENTILATION
S
suction..
cc
<
OAR SCREEN
S
z
DISPOSAL OF SCREENINGS
M
Stored in drvina beds.
ll
COMMINU TOR
S
I
G 1*1 T CHAMBEI1
S
DISPOSAL OF GRIT
M
Stored in dryinq beds.
SCI TLING TANKS
>
SCUM R EMO V AL
cc
<
SLUDGE R CMOV AL
s
£
E F FLU EN T
a
DiGcsrcns
U
No sludge digestion facilities.
TEMPERATURE AND p H
j
GAS PRODUC TION
<
to
HEATING CQIJIPMENT
a.
i/)
RLUDCL PUMPS
o
DRYING DEDS
S
o
V ACUUM FIL TF.R
3
INC INTRA TION
t/i
DISPOSAL OI-" SLUDGE
M
Stored on site.
FLOWMETER AND RECORDER
S
o:
UJ
i
RECORDS
M
Record keeping being institutpd now.
LAO CONTROLS
M
Process control and rpquirpH lah oqnipmpnt h^i ng
0
instituted now.
£ 9
Aeration Basins
M
Singlp «;pppd ^prA+ors limit P.fl control
* •
t J
Secondary Clarifier
1 1
cs I
i !
fjo rpturn <;lnHgp flow mptpr, no wastf sludge flow
V- M
measurino device. Sludge collpct.ion hopppr limits
is
return sludqe flow control. Need handrails..
o «
u 11
UJ d
in
F, F F 1 UTNT
CHLORINATORS
u
Parts just receivpd for r.hlorinat.nr.
z
EFFECTIVE DOSAGE
u
Fecal col i form and r.hlorinp rpqirlnal rtata rpiP^ti onfl
* a
O
CON T AC T TIME
since chlorinator has bppn out. of <;prvirp
X
u
CONTACT TANK
M
Weirs submerged rpsnlt.ing in chopf rirrniting
EPA Form 7500-5 (4-72) PAGE 5
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UMH \n,
| _ _ C, NOTATIONS BY LVALUATOR
1. OPCHAflON AND MAINTENANCE PROBLEMS/DEFICIENCIES
CHECK r/\CH OF THE FOLLOWING IT CMS IN TERMS OF THEIR ESTIMATED ADVERSE AFFECT ON THE PERFORMANCE OF THE PLANT.
ITEM
MAJOR
Ml NO R
worn:
ITEM
MAJOR
MINOR
NONE
ST AF F COMPLEMENT
X
OVERLOADS Uypv.)
PERSGMMEL TRAINING
X
HVDR AULIC
X
OPERATING BUDGET
X
PERIODIC
X
LABORATORY CONTROL
X
CONTINUOUS
INSTRUMENTATION
X
ORGANIC
X
INDUSTPt AL WASTE
X
F ER IODIC
PLANT OBSOLESENCE
X
CONTINUOUS
EQUIPMENT FAILURE:
OVERLOAD C AUSE(S)"
TREATMENT PROCESSES
X
INFILTRATION
X
SLUDGE HANDLING
Y
COMBINED SEWERS
AND PROCESSING
INDUSTRIAL GROWTH
EQUIPMENT MAINTENANCE
X
RAPID POPULATION GROWTH
X
SPARE PARTS INVENTORY
X
INCREASED SERVICE AREA
POWER FAILURE
X
OTHER:
OTH ER
2. DC SC RISE BRIEFLY THE MAJOR PROBLEMS INDICATED ABOVE f include f of tow-up notions needed see Instructions)
See Attached Comments
3. PURPOSE OF INSPECTION
4. GENERAL RATING
n GRANT COMPLIANCE FOLLOW-UP
\X] PERMIT COMPLIANCE Q] OTHER:
ACCEPTABLE
CONDITIONAL ACCEPTANCE
UNACCEPTABLE
X
EVALUATION PERFORMED BY
TITLE
ORGANIZATION
DATE
George Hartmann
Leon Malloy
Chief, 0&M Section
Engineering Technician
EPA
EPA
2/3-5/76
2/3-5/76
Pat Gamroth
State Trainer
Wyoming D.E.Q.
2/3-5/76
INFORMATION FURNISHED BY
TITLE
ORGANIZATION
DATE
Dutch Riebenacht
Operator
Ci ty of Evanston
2/3-5/76
John Proffit
Consulting Engineer
Unitah Engineer
2/3-5/76
EPA Form 7 5 00-5 (R«». 1-74) PAGE 6 PE^HCrs PAijr A 7?> V. I'lfn I S rnr-Ol.r.TE
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TECHNICAL ASSISTANCE PROJECT
EVANSTON, WYOMING WASTEWATER TREATMENT FACILITY
Flow Diagram
December 1975 - February 1976
-» 1 H
-J
Legend
»Sewage
ixed Liquor
^Return Sludge
~ • —~Scum
-rr -^Waste Activated STudge
9 Pumps
> 4
JIT
5
10
a*Y
\J
)
1. Bar Screen & Comminutor
2. Parshall Flume & Flow Sensing Devil
3. Grit Removal System
4. Raw Sewage Wet Well
5. Control Building, Lab, Office and Pump Room
6. Aeration Basin
7. Final Clarifier
8. Chlorine Contact Tank
9. Sludge Drying Beds
10. Anaerobic Digester (Not in use)
11. Chlorine Building
~
1.
i
-r
t
Y
9
v
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Attached photos referred to on page 3, item C-16, are attached to
the City's copy of this report only.
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Item G-2: Evanston, Wyoming
An O&M inspection was performed at the Evanston Municipal Wastewater
Treatment Plant in conjunction with the Technical Assistance that was
given at that time. Attached is a copy of the technical assistance
project report which describes the plant history, assistance given during
the project and recommendations made to improve plant operations.
Major deficiencies found in plant operation and maintenance are
listed below. The listing is not by priority, but the deficiencies
relating to permit violations should be corrected immediately where possible.
(1) The plant chlorinator is broken and needs to be repaired as
soon as possible. Although federal secondary treatment standards have
recently been modified with respect to fecal coliform limitations, the
Evanston facility should still operate its chlorination facilities.
(2) The infiltration/inflow problem which has been responsible for
the plant's hydraulic overload should continue to be studied to determine
the best way to alleviate this problem. If it becomes necessary to bypass
a portion of the plant flow this spring due to extremely high infiltration/
inflow flows, the Wyoming D.E.Q. should be contacted immediately. As
much as possible all flow should be pumped into the plant if possible and then
bypassed to eliminate discharge of raw sewage.
(3) The plant staffing at the present time is barely adequate with
one man responsible for plant operations and maintenance. The City should
endeavor to have another man available to work part time at the plant
for weekends, vacation time and other periods when the present operator
is not on duty during the week or when he requires additional help for
major repair work. It is recommended that 8 hour, 7 day a week operation
be instituted at the plant as soon as, possible.
(4) The present plant does not have an alternate power source or
emergency alarm system when power is lost. The City should investigate
the installation of an emergency power source in the future and should
install an alarm system at the plant as soon as possible.
(5) At the time of the inspection and during the technical assistance
the operator was shown how to use various process control tests to
determine how to control the plant operation. The list of minimum
necessary lab equipment to conduct these tests was given to the City
Engineer at that time. This equipment should be acquired as soon as
possible for use by the operator.
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(6) The basic plant operation and maintenance has been improved
substantially since the visit to the facility on December 2, 1975 by the
EPA. However in order to keep the facility in operation and to conduct
a good preventative maintenance program, adequate tools are required
and proper record keeping should be instituted. In addition the plant
site should be -graded and seeded or sodded to improve the plant appearance.
Good site maintenance eliminates some of the problems encountered from
blowing weeds and mud during the winter and spring months of the year.
(7) The present plant sludge handling facilities appear to be
marginal. It may be necessary for the City to haul waste liquid sludge
from the plant if the existing sludge dryihg beds are found to be
inadequate to process all the waste sludge. Because the waste sludge
which must be put on these beds is not stabilized there may be some
odors at the plant when sludge is put on the beds. Because this sludge
has not been stabilized, the final disposal of this sludge should be
controlled to limit public access to the sludge disposal area. An
acceptable method of final disposal at the present time is to landfill
the sludge after removal from the drying beds. The City should ensure
that the plant facility plan now underway addresses the sludge disposal
problem as landfilling unstabilized sludge is not an acceptable
practice for sludge disposal of federally funded MWWTP's.
(8) In any plant expansion or modification the existing clarifier
sludge withdrawal, sludge return and sludge wasting equipment should
be carefully evaluated for improvements to improve plant operational
control.
The cooperation of the plant operator, city engineer and city
administration officials who have been involved with the EPA in the
Technical Assistance Project have in large part been responsible for
the noticeable improvement in plant operations since the December 2, 1975
visit by the Wyoming D.E.Q. and EPA. It is hoped that through
continued effort the Evanston facility will be producing an excellent
effluent and the present sludge banks in the Bear River below the plant
will no longer be present after the spring runoff. The EPA and State
of Wyoming are both ready to work with the City to help further the
City's efforts in this area.
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