ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
TECHNICAL APPENDIX
MUNICIPAL WASTE-SOURCE
EVALUATIONS
WATER QUALITY INVESTIGATIONS
IN THE
SOUTH PLATTE RIVER BASIN, COLORADO
1971-72
NATIONAL FIELD INVESTIGATIONS C E N TE R-D E N V E R
AND
REGION VIM DENVER. COLORADO
JUNE 1972
tXEA]
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ERRATA
Please note the following errata in this copy of the document:
Page 27, line 20, for 9,900,000/100 ml read 1,900,000/100 ml.
Page 36, line 1, insert the word "by" after the word "reflected."
Page 64, line 23, for level read capacity.
Page 65, line 19, insert the word "capacity" after the word "loading.1
Page 84, line 4, for effluent read influent.
Page 87, line 4, for 12 read 16.
Page 84, line 14, for City Manager read Director of Utilities.
Page 88, under SOD, percent removal (last column to right) insert the
numbers 45 - 86.
Page 93, line 13, for 25 read 20.
Page 122, line 4, for 19,00) read 19,000.
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ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
TECHNICAL APPENDIX
ON
MUNICIPAL WASTE-SOURCE
EVALUATIONS
WATER QUALITY INVESTIGATIONS
IN THE
SOUTH PLATTE RIVER BASIN, COLORADO
1971-72
NATIONAL FIELD INVESTIGATIONS CENTER-DENVER
AND
REGION VIII DENVER, COLORADO
JUNE 1972
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TABLE OF CONTENTS
Section Page
GLOSSARY OF TERMS ill
INTRODUCTION . 1
ARVADA WASTEWATER TREATMENT PLANT .... 3
BAKER WATER AND SANITATION DISTRICT
WASTEWATER TREATMENT PLANT .... .... 9
BOULDER WASTEWATER TREATMENT PLANTS 15
BRIGHTON WASTEWATER TREATMENT PLANT 25
BRUSH WASTEWATER TREATMENT PLANT 31
CLEAR CREEK VALLEY SANITATION DISTRICT
WASTEWATER TREATMENT PLANT .... 39
ENGLEWOOD WASTEWATER TREATMENT PLANT 45
FORT COLLINS WASTEWATER TREATMENT PLANTS 51
FORT LUPTON WASTEWATER TREATMENT PLANT 59
FORT MORGAN WASTEWATER TREATMENT PLANT 63
JULESBURG WASTEWATER TREATMENT PLANT 73
LITTLETON WASTE TREATMENT PLANT 79
LONGMONT WASTEWATER TREATMENT PLANT 87
LOVELAND WASTEWATER TREATMENT PLANT 95
LYONS WASTEWATER TREATMENT PLANT 101
SOUTH ADAMS WATER AND SANITATION DISTRICT
WASTEWATER TREATMENT PLANT 107
SOUTH LAKEWOOD SANITATION DISTRICT
WASTEWATER TREATMENT PLANT 113
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TABLE OF CONTENTS (continued)
Section Page
STERLING WASTEWATEE. TREATMENT PLANT ......... 119
WHEATRIDGE SANITATION DISTRICT
WASTEWATER TREATMENT PLANT ............. 127
ii
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GLOSSARY OF TERMS
BOD - Biochemical Oxygen Demand, 5-Day
COD - Chemical Oxygen Demand
DO - Dissolved Oxygen
MPN - Most Probable Number
NH,N - Ammonia Nitrogen
N02-N0 -N - Nitrite Nitrate Nitrogen
P - Phosphorus
PO, - Orthophosphate
SS - Suspended Solids
TOC - Total Organic Carbon
RM - river mileage (e.g. 311.1/6.7) with first number denoting dis-
tance from mouth of the South Platte River to the confluence
with a tributary stream, and second value indicating distance
upstream of mouth of the tributary stream
cfs - flow rate given in cubic feet per second
gpm - flow rate given in gallons per minute
mgd - flow rate given in million gallons per day
mg/1 - concentration given in milligrams per liter
ymhos/cm - unit of specific conductance (mho — the inverse of
the standard unit of electrical resistance, the ohra)
measured over a 1-centimeter distance, conventionally
made at 25°C
Municipal waste - combination of domestic and industrial wastewaters
discharged to waterways by governmental units, such
as cities or sanitary districts
ill
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INTRODUCTION
This appendix summarizes information concerning the municipal waste
sources investigated in the South Platte River Basin and supplements the
main report entitled, 'Water Quality Investigations in the South Platte
River Basin, Colorado, 1971-72.''
Twenty-three municipal plants were investigated in order to determine
both the adequacy of present treatment practices and the waste loads being
discharged. Included in this appendix is a report on each municipal waste-
water treatment facility evaluated, with the exception of the Metropolitan
Denver Sewage Disposal District #1 plant (Metro) and the Greeley Waste-
water Treatment Plant. These plants are discussed in separate reports
entitled, "Effects of Waste Discharges on Water Quality of the South Platte
River, Denver Metropolitan Area" and "Effects of Waste Discharges on Water
Quality of the Cache la Poudre and South Platte Rivers, Greeley Area."
The format used for presenting specific information on each municipal
plant is as follows:
A. Introduction—includes background information and contacts;
B. Waste Treatment Facilities — includes type of system, number
and sizes (where information was available) of units, and a flow diagram;
C. Discussion of Plant Evaluation and Findings—includes information
on evaluation procedure, data from chemical and bacteriolopical analyses,
visual observations, plant efficiencies, etc.:
D. Summary and Conclusions; and
E. Recommendations
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The waste treatment requirements recommended for a plant were based
on the following factors;
1« Expected low flows in the receiving stream, as determined by
an examination of available flow records;
2. Compliance with applicable water quality standards, e*g», dis-
solved oxygen criteria;
3. Pretreatment of industrial wastes to levels comparable with
that expected of domestic sewage (250 mg/1 BOD and SS) prior to dis-
charge to a municipal treatment plant; and
4. Waste load limits consistent with those being established
for industries under the Refuse Act Permit Program.
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ARVADA UASTEUATER TREATMENT PLANT
5555 UEST 56TII AVENUE
ARVADA, COLORADO
A. INTRODUCTION
The Arvada wastewater treatment plant serves about 50,000 people.
It is located on Ralston Creek (RM 311.1/6.7/0.2), a tributary of Clear
Creek [Figure 1]. The operating staff includes a superintendent, a chief
operator, and two plant operators. The plant is manned eight hours/day,
seven days/week. The budget for 1970 was $338,000 of which $76,000 was
for the collection system, $41,000 for operation of the Arvada plant,
and the remainder for services provided by the Metropolitan Denver Sewage
Disposal District No. 1 plant (Metro) to which Arvada was connected in
1967. Approximately 1.1 mgd is treated by the Arvada plant with the
remainder diverted to Metro.
Primary facilities (clarifier and digester) were originally con-
structed in 1930 using Works Progress Administration (WPA) funds. In
1953, a trickling filter and secondary clarifier were added; chlori-
nation facilities were added in 1967.
In 1964 this plant served a population of 36,000 with an average
flow of 3.5 mgd,— far in excess of the hydraulic capacity of the plant.
Approximately one-third of the flow was treated with the effluent dis-
charged to Ralston Creek. The remaining 2.4 mgd was discharged without
treatment to Clear Creek. No disinfection was provided. As a result
of the 1964 studies, it was recommended that: a) the BOD of the dis-
charge not exceed 30 mg/1 after January 1, 1967: b) disinfection be
provided; c) additional operating staff be provided (in 1964, the plant
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had one operator and one laborer); and d) laboratory analyses be
routinely performed (none were run at'the time of the 1964 survey).
The plant was evaluated by personnel of the National Field Inves-
tigations Center - Denver, August 11-14, 1971, to ascertain improve-
ments in plant operation since the South Platte River Basin Project
studies and to determine the waste loads discharged.
Richard Thomas, Arvada City Manager, and Delmar Dunlap, Chief
Operator, provided information and assistance.
B. WASTE TREATMENT FACILITIES
The Arvada plant has a hydraulic capacity of 1.2 mgd and an organic
capacity of 2,500 Ib/day (250 mg/1 BOD at 1.2 mgd). Flow into the plant
is normally maintained at approximately 1.1 mgd with all flow in
excess of this amount diverted to Metro. Principal components of the
plant are [Figure 1]:
1. Preliminary treatment — bar screen, grit chamber, and comminutor.
2. Primary treatment — clarifier (35 ft in diameter, 7 ft side
water depth (SWD)). Detention time at design flow is about
one hour.
3. Secondary treatment — one high rate trickling filter (78 ft
in diameter, 4 ft 8 in of rock). One clarifier, same size as
the primary.
4. Disinfection — chlorine contact chamber with 16 minutes de-
tention time at design flow.
5. Digestion — two-stage anaerobic designed for a solids loading
2
of 1,680 Ib/ft . The primary digester is 30 ft in diameter
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DIVERTED FLISf 10 MET80 PLANT
PRELIMINARY TREATKEMT
PRIMARY
CLAIiFIER
SLUDGE TO
ANAEROilC
AND THEN
BEOS 112
LOCATION M
TRICKLIN8
FILTER
iECIRCULATION
RALSTON
CREEK
TO PRIMARY
CLARIFIER
SECONDARY
CLA8IFIER
| SLUDGE__J_0
PRIMARY
CLARIFIER
CHLORINE
CONTACT
CHAMBER
----^SLUDGE
NOT TO SCALE
EFFLUENT TO RALSTON CREEK
Figure 1. Wastewaler Treatment Plant, Arvada
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with center depth of 24.5 ft. The secondary digester is 30 ft
in diameter with 21 ft SWD. Sludge is wasted to 12 drying
beds (eight are 25 ft by 50 ft; four are 20 ft by 40 ft).
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
An in-plant evaluation of the Arvada plant commenced on August 11,
*
1971. Three 24-hr composites were collected of the influent and the
effluent after chlorination and analyzed for BOD, TOC, and solids. The
pH, conductivity, and temperature were measured every two hours and
grab samples of the effluent were collected periodically for bacterio-
logical analyses and for measurement of chlorine residual.
Analytical data indicate that the BOD removal efficiencies ranged
from 81 to 90 percent [Table 1]. Disinfection was adequate as evidenced
by the low fecal coliform bacteria densities [Table 2].
Operation and maintenance of the Arvada plant has improved markedly
since the 1964 studies.— The plant effectively treats 1.1 mgd and most
importantly, the raw sewage discharge has been eliminated by diverting
all flows in excess of the design capacity to Metro. Additional per-
sonnel have been employed and laboratory tests (BOD and solids — settle-
able and suspended) are performed twice weekly on the influent and ef-
fluent; total solids and pH of the digested sludge are measured when
drawn; the chlorine residual of the effluent is measured daily. Moreover,
the DO of the receiving water is measured upstream and downstream from
the plant discharge twice weekly.
* Composites were made up of grab samples collected each hour and
composited on a flow weighted basis from measurements at the
headworks.
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TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
ARVADA WASTEWATER TREATMENT FACILITY
AUGUST 11-14, 1971
a/
Parameter-
Flow (mgd)
pH (S.UJ
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
TOC (mg/1)
Total Solids (mg/1)
SS (mg/1)
Settleable Solids (ml/1)
Influent
Range Average
6.2-7,8
18.5-23
520-1,100
150-230 190
78-150 105
670-720 690
90-190 147
4.0-4.5 4.3
Effluent
Range Average
1.06-1.10 1.09
6.8-7.6
19-25
575-1,200
15-44 29
28-37 31
590-620 600
40-60 50
Trace
Percent
Removal
Range
81-90
64-75
55-69
_a/ .Analyses for BOD, TOC, total solids, suspended solids, and settleable solids were performed
on composite samples.
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TABLE 2
BACTERIOLOGICAL RESULTS
ARVADA UASTEWATER TREATMENT FACILITY
Date
August 11, 1971
August 12, 1971
August 13, 1971
Time
0840
1135
1320
1030
1400
1910
0640
1510
Total
Coliform
Count/100 ml
7,300
<100
3,100
1,900
1,600
53,000
240
500
Fecal
Coliform
Count/100 ml
400
<20
16
36
38
72
26
16
Chlorine
Residual
mg/1
1.4
1.2
1.2
1.3
1.4
1.0
1.6
1.7
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8
On the basis of data collected by officials of Arvada and Metro,
there appears to be an infiltration problem in the Arvada collection
system. For example, the influent BOD of samples, collected January 1
to 7, 1971, contained an average of 266 mg/1; an average flow of 2.9 mgd
was diverted to Metro. Samples collected June 29-July 5, 1971, con-
tained 160 mg/1 BOD and the average flow diverted was 3.9 mgd.
D. SUMMARY AND CONCLUSIONS
The Arvada plant effectively treats 1.1 mgd of wastewater and dis-
charges an adequately disinfected waste to Ralston Creek. However,
this flow represents only about 25 percent of the total flow received
at the plant, thus continued operation of the plant for this small
portion does not appear justified.
E. RECOMMENDATIONS
It is recommended that the operation of the Arvada plant be dis-
continued and all wasteflow diverted to the Metro system.
F. REFERENCES
I/ Municipal Waste Report, Metropolitan Denver Area, South Platte
River Basinf U. S. Department of Health, Education, and Welfare,
Public Health Service, Division of Water Supply and Pollution
Control, South Platte River Basin Project, Denver, Colorado,
December, 1964. Appendix B.
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BAKER WATER AND SANITATION DISTRICT
WASTEWATER TREATMENT FACILITY
64TTI AVENUE AND PECOS STREET
DENVER, COLORADO
A. INTRODUCTION
The Baker treatment plant serves a population of approximately
18,000. The high-rate trickling filter process is used with the ef-
fluent being discharged into Clear Creek (RM 311.1/3.4) a tributary
of the South Platte River [Figure 1]. About one mgd of wastewater is
treated by the plant with the remainder, approximately 0.8 mgd, diverted
to the Metropolitan Denver Sewage Disposal District No. 1 plant (Metro).
The Baker plant was constructed in 1957 (design capacity 1.0 mgd) and
chlorination facilities added in 1965. Total cost of the plant was
$331,000.
The plant is staffed by a chief operator and a relief operator and
is manned eight hours/day, seven days/week. The annual operating budget
is approximately $68,000 of which $45,000 is for services provided by
Metro and $23,000 is for plant operation.
An in-plant evaluation in 1964— showed that the plant was serving
17,500 and x
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10
An in-plant evaluation was conducted August 11 through 16, 1971.
Allen Jones, District Supervisor, provided information and assistance.
B. WASTE TREATMENT FACILITIES
The principal components of this plant are as follows [Figure 1]:
1. Preliminary treatment — bar screen, grit chamber, and comminutor.
2. Primary treatment — two clarifiers (rectangular, each
47 ft x 23 ft x 10 ft).
3. Secondary treatment — one high-rate trickling filter (65 ft
in diameter, 7 ft depth), two rectangular clarifiers (same
dimensions as primary units).
4. Disinfection — chlorine contact chamber with detention time
of 15 minutes at 1 mgd.
5. Digestion — two-stage anaerobic digestion, sludge drying beds.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the influent and effluent (after chlorina-
tion) were collected using SERCO automatic samplers. Samples were com-
posited on a flow weighted basis from measurements taken at the plant
headworks. Periodic measurements were made for the pH, conductivity, and
temperature. Grab samples were also collected periodically for bacter-
iological analyses and for chlorine residual measurements. [The analyt-
ical results are given in Table 1.]
The Baker plant discharged about 600 Ib BOD and 350 Ib of SS into
Clear Creek. The BOD removal efficiency was slightly less than the 80
percent minimum required by the 'State.
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IKFLIEBT
TO PRIMAIY
CLARIFIEt
-WATE8
• — --«- SLUIJSE
CMLI1IHE
CINTACT
CNAHIEI
IIVEfiTEB FLOW TO METRO PiABT
Tl YWf»ST£iE
Ig 9l
TKEi Ti
LOCATION MAP
NOT TO SCALE
Tl CLEAi CREEK
Figure 1. Wastewaler Treat^eil Plait, Saker Water
Distritt
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TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
BAKER WATER AND SANITATION DISTRICT
WASTEWATER TREATMENT PLANT
AUGUST 11-16, 1971
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
Total Solids (mg/1)
suspended solids (mg/1)
Settleable Solids (ml/1)
TOC (mg/1)
Influent
Range Average
7.3-7.5
20-23
1,300-2,400
33(£>
1,300-2,700 1,800
140-540 290
5-32 19
270-330 298
Effluent
Range Average
0.97-1.03 1.00
7.4-7.5
20-24
1,600-1,900
70^
1,100-1,200 1,170
30-50 40
0.2-0.6 0.4
137-150 144
Percent Removal
79
78-91
47-59
a./ Analyses for BOD, TOC, total solids, SS, and settleable solids were performed on
composite samples.
b/ This is a single value.
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12
Disinfection was adequate [Table 2]; however, it would appear from
the high chlorine residuals observed that an excessive amount of chlorine
was being applied.
D. SUMMARY AND CONCLUSIONS
Waste treatment practices have improved since the 1964 studies. The
Baker plant can adequately treat 1.0 mgd of wastewater; however, it is
feasible for the entire flow to be diverted to the Metro system and for
operation of the Baker plant to be discontinued.
Chlorine, in excess of that required for adequate disinfection, was
applied during the survey. This practice is considered wasteful and,
i
at the chlorine residuals measured, could have a detrimental effect on
the receiving waters.
E. RECOMMENDATIONS
It is recommended that the operation of the Baker plant be discon-
tinued and all wasteflow be diverted to the Metro system.
F. REFERENCE
17 Municipal Waste Report, Metropolitan Denver Area, South Platte
River Basin, PR-3, U. S. Department of Health, Education, and
Welfare, Public Health Service, Division of Water Supply and
Pollution Control, South Platte River Basin Project, Denver,
Colorado, December 1965. Appendix B.
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13
TAJLE 2
BACTERIOLOGICAL RESULTS
BAKER WATER AMD SANITATION DISTRICT
WASTEWATER TREATMENT FACILITY
Date
August 11, 1971
August 12, 1971
August 13, 1971
Time
0800
1200
1340
1050
1410
1900
0620
1525
Total
Coliform
Count/100 ml
<100
65
<100
8
830
130
50
12
F«cal
Coliform
Count/100 ml
<20
<20
<20
<2
14
<2
4
2
Chlorine
Residual
«I/1
2.4
2.3
2.1
l.f
1.8
2.4
2,7
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14
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15
BOULDER WASTEWATER TREATMENT PLANTS
BOULDER, COLORADO
A. INTRODUCTION
The City of Boulder has two wastewater treatment plants, both
located on Boulder Creek. The Pearl Street plant (RM 270.0/17.4/21.3)
is a high-rate trickling filter system designed for an average flow of
4.3 mgd. This plant was constructed in 1957 at a cost of $1,100,000.
The 75th Street plant (RM 270.0/17.4/17.8), constructed in 1968 at a
cost of $1,819,000, is also a high-rate trickling filter facility de-
signed for 5.2 mgd.
Both plants are operated continuously. The superintendent of sewer
plant operations, Robert Hall, is responsible for both plants. The
staff at the Pearl Street plant includes a supervisor, five operators,
a mechanic, and a maintenance man. The 75th Street plant staff includes
a supervisor, six operators, a mechanic, two maintenance men, and a
laboratory technician who serves both plants. The operating budget in
1971 for these two plants was more than $300,000.
In 1967,— the Pearl Street plant was seriously overloaded due to
rapid population growth (population served was 56,000) and high rates of
infiltration in older portions of the collection system with open sewer
joints. Flows as high as 7.5 mgd were reported. Effluent from the
plant was seriously degrading the waters of Boulder Creek. The 75th
Street plant was under construction at that time to relieve the overloaded
condition at the Pearl Street facility.
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16
Both plants were evaluated, August 17 through 20, 1971, by personnel
of the National Field Investigations Center - Denver. Mr. Hall provided
information and assistance during these «vslu©tions.
B. WASTE TREATMENT FACILITIES
1. Pearl Street Plant - Relatively steady flow conditions are made
possible because flow in excess of the plant capacity can be diverted to
the 75th Street plant for treatment. Principal components of the Pearl
Street plant [Figure 1] ares
a) preliminary treatment — bar screen„ grit chamber, and commin-
utor;
b) primary treatment — one clarifier (110 ft in diameter, 7 ft
deep);
c) secondary treatment — one trickling filter (175 ft in diameter,
3.5 ft deep) and one clarifier (100 ft in diameter, 9 ft deep);
d) disinfection — chlorine contact chamber with detention time
of 15 minutes at a flow of 4.2 mgd; and
e) digestion ~ two-stage anaerobic system (each digester 55 ft
in diameter by 28 ft deep). (Sludge can be treated at this plant or
transferred to the 75th Street plant,) Laboratory analyses are performed
routinely at both plants for several parameters including BOD, suspended
and settleable solids, volatile acids and pH.
2. 75th Street Plant - Principal components [Figure 2] of the 75th
Street plant are as follows:
a) preliminary treatment - bar screen, grit chamber, and commin-
utor;
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INFLIENT
T6 PRS1A8Y
CLAIIFiEi
SECIHIA1Y
ClARfflER
CNL8BIHE
CSHTACT
CHAMBER
EKESS FL6W T0 B9HLIER 7$tfe
STREET PLSKT
--*-SLSBIE T8 TW8-ST41E
ANAERIBIC eilESTO
AK8 THEN T§ glfl^S ilBS
LOCATION MAP
SLOD_SE_TJJRJ!«ASY
CLARIFIES
BOULDER
PEARL ST
PLANT
BOULDERf
CREEK
KEY
WATER
SLUD«E
NOT TO SCALE
EFFLHEHT Tl I9ILBER CREEK
Figure 1. Waslewater TrealmeHt PUal ' East Pearl Slrcel
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IKFL8E9T
/ PHIIJW \
I CUB1FIEI f
SL8ISE T8
l«E18§i£
IIIEiTEiS SS
/^ ^\
I T1ICKIH6 \
\ FILTEI /
vv
BOULDER
75TH ST
PLANT
CHLIIIINE
CINTACT
CKAMIEI
-*~- SLUDGE
NOT TO SCALE
EFFLUENT I1HLBEI CREEK
Figure 2. Wastewater TreatMfnt PUaJ.TStfe St.
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17
b) primary treatment - two clarifiers (each 80 ft in diameter, 7 ft
deep) operating in parallel;
c) secondary treatment - two trickling filters (each 155 ft in
diameter, 8 ft deep) operated in parallel and two clarifiers (each
80 ft in diameter, 8 ft deep);
d) disinfection - chlorine contact chamber with detention time of
15 minutes at design capacity; and
e) digestion - two-stage anaerobic digester system, vacuum filters,
and sludge beds.
An expansion program presently underway at this plant will increase
the capacity to 15.6 mgd (completion date, October 1972). This expansion
will provide a total wastewater treatment capacity (both plants) of
19.8 mgd. The additional facilities to be added are a primary clarifier
(140 ft in diameter, 7 ft deep), two trickling filters (200 ft in diameter,
5 ft deep) in parallel, a secondary clarifier (140 ft in diameter, 7 ft
deep), and an enlarged chlorine contact chamber which will provide 15
minutes detention time at a flow of 15.6 mgd.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hour composites of the influent and effluent (after chlorin-
ation) were collected at both plants from August 17 through 20, 1971.
The composites were made up from grab samples collected manually each half
hour from the influent and each hour from the effluent. The samples were
composited on a flow weighted basis from measurements at the headworks.
Temperature, pH, and conductivity were measured hourly at each sampling
-------
location. Grab samples were collected periodically for bacteriological
analyses and chlorine residual measurements. [The results of the chemical
and bacteriological analyses are contained in Tables 1 through 4.]
The BOD removal efficiency ranged from 45 to 77 percent at the
Boulder Pearl Street plant. During the survey, the digesters were out
of operation and sludge was being stored in the primary clarifier.
Excessive solids were carried over from the primary clarifier, adversely
affecting other plant operations. Repairs on the digesters were completed
shortly after the survey. Solids were also observed in the chlorine
contact chamber and in the final effluent. The sludge accumulations in
the chamber were subsequently removed. This plant was providing adequate
disinfection at the time of the survey.
The 75th Street plant [Table 2] removed 60 to 90 percent (average
77 percent) of the BOD. Flows exceeded the design capacity by 50 percent.
An expansion program is currently underway to double the hydraulic capacity
of the plant. The bacteriological analyses showed disinfection was
adequate during the survey except on one occasion when the chlorinator
was out of operation [Table 4].
21
A stream survey in September 1971— showed that the discharge from
the two Boulder treatment plants degraded water quality and the stream bed
environment of Boulder Creek. Violations of Sections B and D of the
Colorado Basic Standards Applicable to All Waters of the State occurred.
However, conditions were less severe during the September 1971 stream survey
O /
than those reported in 1967.—'
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TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
BOULDER PEARL STREET WASTEWATER TREATMENT FACILITY
AUGUST 17-19, 1971
a/
Parameter-
Flow (mgd)
pH (S. U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
COD (mg/1)
TOC (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Settleable Solids (ml/1)
Influent
Range Average
6.5-7.7
18.5-23.5
400-630
130-170 140
240-1,160 700
114-123 117
750-1,060 925
120-150 130
&
Effluent Percent
Range Average Removal
3.55-4.29 4.00
6.7-7.5
19,5-23.5
125-5.10
30-75 48 42-77
115-185 150 23-90
24-43 34 62-80
220-370 355
18-50 36 66-83
Trace—
a/ Analyses for BOD, COD, TOC, Total Suspended and Settleable Solids were performed on
composite samples.
b/ This is a single value.
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SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
BOULDER 75TH STREET WASTEWATER TREATMENT FACILITY'
AUGUST 17-20, 1971
a/
Parameter-
Flow (mgd)
pH (S. U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
TOG (mg/1)
COD (mg/1)
Total Solids (rag/1)
Suspended Solids (mg/1)
Settleable Solids (ml/1)
Influent
Range Average
6.5-8.0
18-22
410-800
160-190 173
84-123 105
260-520 373
400-560 497
110-130 120
0.35^
Effluent
Range____ J^era.ge__
7.73-8.03 7.84
6.3-7,6
16-21.5
525-1,000
16-75 41
21-29 25
110-230 153
370-490 433
15-35 28
a/
Trace-
Percent
Removal
60-90
75-78
54-67
64-83
a/ Analyses for BOD, TOG, COB, Total, Suspended, and Settleable Solids were performed on
composite samples.
b/ This is a single value.
-------
TABLE 3
BACTERIOLOGICAL RESULTS
BOULDER PEARL STREET WASTEWATER TREATMENT PLANT
21
Date
August 17,
August 18,
August 19,
Date
August 17,
August 18,
August 19,
Time
1971 0800
1030
1300
1971 0930
1430
1930
1971 0700
1530
BOULDER
Time
1971 0935
1035
1300
1971 0800
1430
1925
1971 0700
1530
Total
Coliform
Count/100 ml
1,300
220
320
200
180
420
340
120
TABLE 4
Fecal
Coliform
Count/100 ml
20
22
22
6
31
62
19
2
Chlorine
Residual
mg/1
1.5
1.2
1.4
1.5
1.2
1.5
2.1
1.3
BACTERIOLOGICAL RESULTS
75TH STREET WASTEWATER TREATMENT FACILITY
Total
Colif orm
Count/100 ml
3,400
820
450
>80,000
170
28,000
250
4,000
Fecal
Coliform
Count/100 ml
32
20
<2
>6,000
7
560
19
12
Chlorine
Residual
mg/1
2.5
1.9
2.0
0.0
1.6
1.6
0.7
-------
Low-flow conditions for Boulder Creek for a 20-year period, 1951-70,
were examined at a U.S.G.S. gaging station (KM 28.9); the seven-day, ten-
A
year low flow is 3.3 cfs. Tributary inflows (e.g. South Boulder Creek)
and accretions (during the non-irrigation season) increase the flow
between the gaging station and the points of discharge from the Boulder
treatment plants. If it is assumed that flow downstream from South Boulder
Creek is 25 cfs (not including the Pearl Street discharge) then, in order
to maintain a DO level of 5.0 mg/1, the plant discharges can contain no
more than 20 mg/1 BOD.
D. SUMMARY AND CONCLUSIONS
1. The BOD removal efficiencies at the two Boulder plants did not
meet the Colorado requirements for secondary treatment because of opera-
tional difficulties at the Pearl Street plant and hydraulic overloading
at the 75th Street plant. Moreover, additional treatment is required
at the two plants if the stream standards are to be met.
2. Adequate disinfection was generally provided at both plants
during the survey.
3. Infiltration in the older portions of the collection system
contribute to the hydraulic overloading of the 75th Street plant.
4. The planned expansion at the 75th Street plant should alleviate
the hydraulic-overload conditions observed during the survey.
* Low-flow conditions for the period of record occurred during the non-
irrigation season, October to May.
-------
23
E. RECOMMENDATIONS
It is recommended that:
v
1. The biochemical oxygen demand and the suspended solids in the
effluents from the Boulder plants not exceed 20 mg/1 or 3,300 Ib/day
of each (700 Ib/day from the Pearl Street plant and 2,600 Ib/day,
75th Street plant), whichever is less.
2. The infiltration into the collection system be reduced.
F. REFERENCES
7
Jl/ Status of f'hmicipal Waste Treatment in the South Platte River
Basin,, Colorado, 1964-1967, U. S. Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967 (unpublished report).
2] Water Quality Investigations in the South Platte River Basin.,
Colorado, 1971-1972, U. S. Environmental Protection Agency,
•National Field Investigations Center - Denver and Region VIII,
Denver, Colorado, April 1972.
_3/ Effects of Pollution on Aquatic Life Resources of the South
Platte River Basin in Colorado, U. S. Department of the Interior,
Federal Water Pollution Control Administration, South Platte River
Basin Project, Denver, Colorado and Technical Advisory and In-
vestigation Branch, Cincinnati, Ohio, Report PR-11, December 1967.
-------
25
BRIGHTON WASTEWATER TREATMENT PLANT
BRIGHTON. COLORADO
A. INTRODUCTION
The Brighton wastewater treatment plant, a standard-rate trickling
filter plant, serves approximately 10,000 people. The plant is manned
eight hrs/day by one operator. The effluent is discharged to the
South Platte River (RM 295.8).
An in-plant survey conducted in 1964-- indicated that the Brighton
wastewater treatment facility was providing 95 percent BOD and 84 percent
suspended solids removal. The average flow of 0.65 tngd was below plant
design and chlorination facilities were providing adequate disinfection
of the effluent.
The in-plant evaluation was conducted from September 27 through 29,
1971. C. B. Dornbusch, Director of Public Works, and Edward Finley,
Plant operator, provided information and assistance.
11. WASTE JJ^ATMENT_ FACILITIES
The plant is designed for a capacity of 1.8 ragd. The principal
components [Figure 1] of this system are:
1. Preliminary treatment — grit chamber, bar screen and comminutor:
2. Primary treatment — clarifier (65 ft in diameter, 12 ft deep);
3. Secondary treatment — trickling filter (80 ft in diameter and
6 ft deep) and clarifier (55 ft in diameter, 9 ft deep);
4. Chlorine contact chamber (58 ft by 9 ft by 5 1/2 ft) with
average detention time of 23 minutes at present flows; and
5. Two-stage anaerobic digestion system.
-------
The plant is presently under expansion, with financial assistance
from an EPA grant. The expansion will cost $861,000 and is scheduled
for completion January 1973. Included in the expansion are: a) addition
of a headworks building with automatic bar screens and grit chambers•
b) modification of existing primary clarifier to provide automatic sludge
removal; c) two additional trickling filters (each 90 ft in diameter and
6 ft deep); d) a second chlorine contact chamber; e) replacement of piping
in clarifiers and arms on existing trickling filter; and f) cleaning and
repair of existing digesters.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the influent and effluent (after chlorin-
ation) were collected using SERCO automatic samplers and composited on
a flow weighted basis from readings obtained at the headworks. Temperature,
pH, and conductivity were measured periodically. Grab samples of the efflu-
ent (after chlorination) were collected for bacteriological analyses and
measured for chlorine residual.
During the survey the following visual observations were made.
1. Groundwater from excavation for the new headworks building
was pumped into the primary clarifier, thus reducing the clarifier's
effectiveness.
2. The existing scum receptacle must be cleaned manually. As
operators are on duty only 16 hr/day, the receptacle filled at night
and allowed floating material to pass over the weirs and flow to the
trickling filter. This will be corrected after completion of the
present expansion program.
-------
INFLUENT
PIELIMINA1Y TtlATBENT
NOT TO SCALE
DRYING BESS
KEY
——- SLU06E
——— WSTEK
EFFL8EWT
SOUTH PLATTE RIVER
Figure 1. Waslewater Treatment Plant , Bri
-------
27
3. The rock medium in the existing trickling filter was too small,
allowing ponding to occur.
4. Laboratory facilities have been provided at the plant for the
performance of chemical tests of sewage quality. The numbers and types
of chemical tests performed were limited to only basic analyses (e.g.
pH, chlorine residual, and temperature). Records of plant operation
reflect flows and normal maintenance procedures. The operator should
be trained to perform necessary tests to provide efficient operation
of the plant.
The data collected during the 1971 survey [Table 1] show that the
efficiency of BOD removal ranged from 50 to 74 percent, less than the
80 percent minimum level required by the State of Colorado. There was
no detectable chlorine residual in the effluent throughout the survey.
The plant maintains a chlorine dosage rate of 20 to 25 Ib/day, the equi-
valent of approximately 2 mg/1, which is less than the Colorado State
2 /
recommendations of 15 mg/1 in a trickling filter effluent.— The State
also requires a chlorine residual level of 1 mg/1 after 15 minutes de-
tention time at peak hourly flow. The inadequacy of disinfection is re-
flected in the high fecal coliform bacterial densities detected in the
effluent [Table 2] ranging from 340,000 to 9,900,000/100 ml during
the survey.
D. CONCLUSIONS
1. The plant performance dia not conform to the minimum require-
ment of 80 percent BOD removal, as established by the State of Colorado,
and the effluent is inadequately disinfected.
-------
28
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
BRIGHTON WASTEWATER TREATMENT FACILITY
September 28-30, 1971
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity
(ymhos/cm)
liOD (mg/1)
Total Solids
(mg/1)
S1 upended Solids
(mg/1)
: (mg/1)
Total N
(mg/1)
NH3 (mg/1)
NO + NO
(mg/1)
Total P
(mg/1)
Influent
Range
7.3-7.7
15-20
1400-3250
100-230
1810-1960
160-200
100-290
21-22
13-15
0.06-0.92
8-11
Effluent
Avg RsnSe
1.2-1.4
7.1-8.1
16-20
2000-3000
156 50-60
1880 1500-1590
175 60-100
160 50-70
22 16-19
14 12-13
0.45 0.11-0.37
10 8.6-9.6
Avg
1.3
53
1550
80
55
18
12
0.23
9.1
Percent
Removal
50-74
17-19
50-65
50-75
a/ Analyses for BOD, total solids, suspended solids, TOC, total N, NH,, N00 + NO,,, and
total P were performed on composite samples.
-------
29
TABLE 2
BACTERIOLOGICAL RESULTS FOR BRIGHTON WASTEWATER TREATMENT FACILITY
Date
9/27/71
9/28/71
Time
1510
0740
1710
Total Coliform
Count/100 ml
> 800,000
> 800,000
8,900,000
Fecal Coliform
Count/100 ml
1,000,000
860,000
340,000
C12 Residual
mg/1
0.0
0.0
0.0
9/29/71 1110 8,800,000 1,900,000 0.0
-------
30
2. The Brighton wastewater treatment plant is currently being
expanded. The expanded facilities are scheduled to be in operation
in January 1973.
3. Laboratory facilities have been provided but are not used to
provide the most efficient operation of the plant.
E. RECOMMENDATIONS
It is recommended that:
1. Until the new treatment facility is placed in operation, the
chlorine dosage rate be increased to insure adequate disinfection of
the effluent.
2. The operator receive formal training in the operation of this
plant by schooling and by on-the-job training.
3. The biochemical oxidation demand and suspended solids in the
Brighton Treatment Plant effluent not exceed 30 mg/1 or 440 Ib/day of
each at design flow, whichever is less,
F. REFERENCES
I/ Ihmicipal Waste Report,, Metropolitan Denver Area., South Platte
River Basin, PR-3, U. S. Department of Health, Education, and
Welfare, Public Health Service, Division of Water Supply and
Pollution Control, South Platte River Basin Project, Denver,
Colorado, December 1965. Appendix B.
21 Criteria Used in the Review of Waste Water Treatment Facilities,
Colorado Department of Health, Denver, Colorado, September 1969.
-------
31
BRUSH WASTEWATER TREATMENT PLANT
BRUSH, COLORADO
A. INTRODUCTION
The Brush wastewater treatment plant serves a population of approxi-
mately 3,500 and treats wastewater (approximately 0.5 mgd) from the
Sigman Meat Company. The present plant was constructed in 1966 as a
replacement for one that was destroyed in the 1965 flood of the South
Platte River. The plant is manned eight hrs/day, five days/week by one
operator. The effluent is discharged by the municipal plant to the Platte
River at RM 185.6.
In 1967— this plant was treating 0.55 mgd (0.34 mgd contributed
by Sigman Meat Company). The chlorination facilities were not in oper-
ation at that time.
The in-plant survey was conducted from January 25 through 29, 1972.
John West, City Manager, and Jesse Law, plant supervisor, provided in-
formation and assistance.
B. WASTE TREATMENT FACILITIES
The plant is designed for a capacity of 0.9 mgd. The principal
components are [Figure 1]:
1. Preliminary treatment — manual bar screen, grit chamber,
and comminutor;
2. Primary treatment — clarifier, (50 ft in diameter and 10 ft
deep) — at 1.1 mgd the surface overflow rate was 560 gpd/ft
with a detention time of 3.2 hr;
3. Secondary treatment — two high-rate trickling filters operated
-------
32
in series (each 100 ft in diameter and 7 ft deep) , with small
rock (2 1/2 in.) being used as the trickling filter media and a
clarifier (50 ft in diameter and 10 ft deep) — at 1.1 mgd the
2
surface overflow rate was 560 gpd/ft with a detention time of
3.2 hr;
4. Disinfection — chlorine is added to the effluent from the final
clarifier with a 1,200 ft outfall line to the river providing
the detention time; and
5. Digestion — one heated digester (55 ft in diameter and 24 ft
deep) with the supernatant and digested sludge used for ferti-
lizer on non-edible crops.
C. DISCUSSION OF PLANT EVALUATION AND^ FINDINGS
Three 24-hr composites of the effluent from the Sigman Meat Company,
the combined influent to the treatment plant, and the effluent from the
plant (after chlorination) were collected using SERCO automatic samplers
on January 26, 28 and 29, 1972. Samples were composited on a flow weighted
basis from readings obtained at the headworks. Temperature, pH, and con-
ductivity, of the treatment plant influent and effluent were measured
periodically. Grab samples of the effluent were collected for bacterio-
logical analyses.
During the survey, it was noted that:
1. The arms of the first trickling filter were not rotating freely
because of the buildup of grease, from the packing company, on the bearings,
2. The weirs on the primary clarifier were not level, which caused
uneven flow distribution; and
-------
INFLUENT
LOCATION MAP
BRUSH
PLANT
1 8O S
BRUSH"!
NOT TO SCALE
C11IINEI
/ \
— { ""SIE")
"
SLUDGE SPREAi
ON FIELDS
TRICKLING
FILTER
CHLORINE
CONTACT
CHAMiER
EFFLUENT
SOUTH PLATTE RIVER
KEY
--- ,* -- SLUDGE
Figure 1. Waslewtttr Trealmenl PlaHl , Brush
-------
33
3. The chlorination equipment was not in operation because of equip-
ment malfunction. Plant officals indicated a new chlorinator is on order.
4. Routine maintenance of plant facilities was being provided.
5. Laboratory analysis are performed on the quality of the sewage
and on Sigman Meat Company effluent. BOD tests are run daily on both
the Sigman effluent and the treatment plant effluent. In addition
suspended and settleable solids measurements are made of the plant effluent.
The Sigman Meat Company processes about 2,400 hogs per day, five
days a week. Wastewaters receive primary treatment to remove grease
and solids prior to discharge into the Brush municipal sewers. During
the 1972 survey the BOD and suspended solids in the meat company wastes
ranged from 1,030-1,200 mg/1 and 664-1,780 mg/1, respectively [Table 1].
Waste loads from Sigman constitute more than 70 percent of the BOD load
and more than 50 percent of the suspended solids load to the Brush treat-
ment plant.
Removal efficiencies of BOD and SS, at the Brush plant, ranged from
83-85 and 94-98 percent, respectively [Table 2]. Although the BOD re-
moval efficiency was greater than the 80 percent minimum removal required
by the State of Colorado, the effluent BOD (average level of 140 mg/1) is
considered excessive. The high influent BOD (610-1,320 mg/1) is a result
of the waste loads from the Sigman Meat Company. To be consistent with
waste discharge limits established for industry under the Refuse Act Permit
Program, the effluent from the Brush plant should contain no greater than
30 mg/1 of BOD and SS. In order to accomplish this objective, pretreat-
ment of the Sigman wastes is necessary so as to reduce BOD levels to those
comparable with domestic sewage (250 ing/1) .
-------
34
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
SIGMAN MEAT PACKING PLANT, BRUSH, COLORADO
JANUARY 26-28, 1972
Parameter-
Flow
pH (S
Tempe
(mgd)
.U.)
rature
(°C)
Effluent
Range
0.5-0.7
6.3-6.8
9-13
Average
0.6
Conductivity (ymhos/cm) ]
BOD (mg/1) 1,030-1,200 1,140
COD (mg/1) 2,130-4,550 3,070
Total Solids (mg/1) 1,720-3,220 2,280
Suspended Solids (mg/1) 664-1,780 1,080
a./ Analyses for BOD, COD, total solids, and suspended solids were
performed on composite samples.
b_/ This is a single value.
-------
TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
BRUSH WASTEWATER TREATMENT FACILITYJANUARY 26, 28, and 29, 1972
Parameter--
Flow (mgd)
pil (S.U.)
Temperature (°C)
Conductivity (umhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Ranpe Average
6.6-7.3
14-19
850-1,100
610-1.320 860
1,620-2,180 1,810
1,200-3,320 2,256
535-1,580 1,118
Effluent
Ranpe
1.07-1.21
7.5-7.9
4.0-11.5
900-1,250
100-220
143-450
698-920
29-74
Average
1.11
140
337
773
45
Percent
Removal
83-85
74-91
41-79
94-98
a/ Analyses for COD, COD, total solids, and suspended solids were performed on composite samples.
-------
36
Disinfection was not provided as reflected bacteriological analysis
[Table 3]; this is in violation of Colorado standards.
D. SUMMARY AND CONCLUSIONS
1. Although the BOD removal efficiency at the Brush plant ranged
from 83-85 percent, the effluent BOD level was still excessive. Violations
of the Colorado Water Quality Standards occurred for inadequate disin-
fection of municipal waste effluents.
2. The waste loads discharged from the Sigman Meat Company con-
stituted more than 70 percent of the BOD and more than 50 percent of the
suspended solids loads to the Brush plant. Grease from the meat company
caused operational problems in the trickling filters by building up on
the bearings and preventing free rotation of the filter arms.
3. Operation of the plant is not adequate. Operator training is
required.
E. RECOMMENDATIONS
It is recommended that:
1. The Sigman Meat Company pretreat wastes to the degree such that
the effluent contain levels of biochemical oxygen demand and suspended
solids equivalent to that in domestic wastes (250 mg/1).
2. The effluent from the Brush plant contain no more than 30 mg/1
or 300 pounds each of biochemical oxygen demand and suspended solids,
whichever is less.
3. Disinfection be provided in accordance with state regulations
and the plant effluent contain no more than 1000 fecal coliform bac-
teria/100 ml.
-------
37
TABLE 3
BACTERIOLOGICAL RESULTS
BRUSH WASTEUATER TREATMENT FACILITY
January
January
January
Date
26, 1972
27, 1972
28, 1972
Time
1045
1145
1000
1100
1035
1200
Total
Colifomi
Count/100 ml
>8, 000, 000
>8, 000, 000
16,000,000
28,000,000
8,200,000
960,000
Fecal
Coliform
Connl:/ino ml
11,000,000
9,000,000
6,200,000
6,700,000
5,100,000
140,000
-------
38
4. The weirs in the primary clarifier be leveled to prevent uneven
flow distribution.
5. The plant operator be provided training in the operation of the
plant by attendance at an operator school and be given on-the-job
training.
F. REFERENCE
_!/ Status of Municipal Waste Treatment in the South Platte River Basin,
Colorado, 1964-67, U. S. Department of the Interior, Federal Water
Pollution Control Administration, South Platte River Basin Project,
December 1967.
-------
39
CLEAR CREEK VALLEY SANITATION DISTRICT
WASTEWATER TREATMENT PLANT
ARVADA, COLORADO
A. INTRODUCTION
The Clear Creek Valley Sanitation District plant (RM 311.1/7.0)
treats the domestic wastes from approximately 13,000 people (which
includes the Ridge Home for Retarded Children), and industrial wastes
from Sigman Meat Company and Containers Incorporated. The plant is
staffed by four operators who man the plant sixteen hours/day, seven
days/week. The primary facilities were constructed in 1952; a trick-
ling filter and secondary clarifier were added in 1960, followed by
"Rapid Floe" aeration in 1967. At that time the old clarifier was
converted to a chlorine contact chamber and new secondary clarifier
units were installed.
In 1964,— this plant was providing inadequate treatment. It was
hydraulically and organically overloaded (plant capacity of 0.85 mgd
with influent BOD of 865 mg/1 as a result of the Sigman Meat Company
wastes). Chlorination facilities were available but not in use. There
were no laboratory facilities and no plant operation records were main-
tained. The District originally considered connecting to the Metro-
politan Denver Sewage Disposal District No. 1 plant (Metro), but
subsequently decided to build additional treatment facilities instead.
Personnel from the National Field Investigations Center-Denver
conducted an in-plant evaluation from August 11-14, 1971. Orval Smith,
District Superintendent, provided assistance and information on the
Clear Creek system.
-------
40
B. WASTE TREATMENT FACILITIES
The design capacity of this plant is 2.1 mgd. Treatment facilities
[Figure 1] include;
1. Preliminary treatment — bar screen, grit chamber, and comminutor.
2. Primary treatment — one clarifier (30 ft by 90 ft by 8 ft-
Link Belt).
3. Secondary treatment —• one high-rate trickling filter (90 ft in
diameter, 7 ft deep), aeration units, two rectangular tanks of
2 mgd each (34 ft by 93 ft by 9 ft deep) , elarifier (93 ft by
37 ft by 16 1/2 ft deep).
4. Disinfection ~ chlorine contact chamber is an old secondary
clarifier (40 ft in diameter, 7 ft deep).
5. Digestion — two-stage anaerobic system (primary digester—37 ft
in diameter, 25 ft high; secondary digester, 25 ft in diameter
by 25 ft high); digested sludge is placed in drying beds.
Flow is metered by a Parshall flume and continuously recorded and
totalized.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the plant influent and effluent (after
chlorination) and the wastewater from Sigman were collected from
August 11 through 14, 1971. Temperature, pH, and conductivity measure-
ments were made every two hours and grab samples of the effluent were
collected periodically for bacteriological analyses and measurement of
chlorine residual.
* Grab samples were collected manually every hour and composited on a
flow weighted basis from flow measurements at the headworks.
-------
MAIN INFLUENT
SIGMAN INFLUENT
PRELIMINARY TREATMENT
. ^ SLIteSE TO TWO-STAGE
ANAEKIBIC DIGESTERS
AN> TtiEK T8 SBYING BEDS
RECI8CULATION TO
PRIMARY CLARIFIER
RETURN
ACTIVATED
SLUDGE TO
EXTENDED
AERATION
WASTE ACTIVATED SLUDGE
La* KB. ^Mm, ^^ m^ ^^ ^^ ^^ —"" amimm ^BB ne
TO PRIMARY CLARIFIER
EXTENDED
AERATION
SYSTEM
CLEAR
CREEK
VALLEY
PLANT
KEY
-WATER
1 CHLORINE CONTACT
CHAM1ER
NOT TO SCALE
_ — —SLUDGE
EFFLUENT TO CLEAR CREEK
Figure 1. Waste water Treatment Plant-Clear Creek Valley SasiSalion District
-------
41
The Sigman Meat Company contributed about 3,600 Ib of BOD (1,200
mg/1) and 1,750 Ib of SS (587 mg/1) to the Clear Creek plant during the
survey. This waste load has not significantly changed since the 1964
survey. Total influent waste loads averaged approximately 6,000 Ib BOD
and 3,000 Ib SS. Survey data [Table 1] show that the Clear Creek plant
was providing 93-95 percent removal of BOD. Flows averaged 2.5 mgd
during the survey — exceeding design capacity about 20 percent. Instan-
taneous flow readings ranged from 1.75 to 3.1 mgd. During daylight hours
the flow generally ranged from 2.0 to 3.1 mgd. It was during these peri-
ods that solids were observed carried over from the final clarifier into
the chlorine contact chamber. Moreover, the weirs of the final clarifier
were submerged during peak flows.
Chlorine residuals ranged from 0.5-1.4 mg/1 and, except for the
first day of the survey, disinfection was effective as evidenced by fecal
coliform bacteria densities [Table 2].
This plant is located in proximity to the Clear Creek interceptor
of the Metro system. Connection to this interceptor is a reasonable
alternative to plant expansion.
D. SUMMARY AND CONCLUSIONS
Treatment has improved markedly since the 1964 project studies.
Overall plant operation and maintenance, including the staffing and
routine laboratory analyses, are adequate. However, population growth
in the service area and increased flows during the summer months have
caused hydraulic overloading of the plant and subsequent solids
carry-over.
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
CLEAR CREEK VALLEY WASTEWATER TREATMENT FACILITY
AUGUST 11-14, 1971
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (eC)
Conductivity
(ymhos/cm)
BOD (mg/1)
TOC (mg/1)
Suspended Solids (mg/1)
Sefctleable Solids (ml/1)
Influent
Range Average
6.8-9.0
20-23
700-2,400
220-350 285
72-102 96
100-170 143
& 2
Effluent
Range Average
2.45-2.57 2.50
7.1-7.6
21-23
1,200-1,500
15-19 17
19-29 22
20-70 36
Traee-2.5 1.5
Percent Removal
93-95
69-81
59-87
a/ Analyses for BOD, TOC, suspended solids, and settleable solids were performed on
composite samples.
b_/ All values are equal.
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43
TABLE 2
BACTERIOLOGICAL RESULTS
CLEAR CREEK VALLEY WASTEWATER TREATMENT FACILITY
Date
August 11, 1971
August 12, 1971
August 13, 1971
Time
0930
1120
1300
1015
1340
0650
1450
Total
Coliform
Count/ 100 ml
24,000
290,000
6,600,000
310,000
62,000
1,100
21,000
Fecal
Coliform
Count/ 100 ml
520
32,000
57,000
420
33
6
68
Chlorine
Residual
mg/1
0.6
0.5
0.5
0.6
0.6
1.4
0.8
-------
The district could connect to the Clear Creek interceptor and divert
all flow into the Metro systems precluding the need for further plant
expansion.
E. RECOMMENDATIONS
It is recommended that:
1. The Clear Creek Valley Sanitation District discontinue operation
of the existing plant by connection to Metro when the latter facility
has adequate capacity to treat these waste loads.
2. The Sigman Meat Company pretreat wastes to the degree such that
the effluent contain levels of biochemical oxygen demand and suspended
solids comparable to that in domestic wastes (250 mg/1).
F. REFERENCE
I/ Municipal Waste Report, Metropolitan Denver Area, South Platte
River Basin, U. S. Department of Health, Education, and Welfare,
Public Health Service, Division of Water Supply and Pollution
Control, South Platte River Basin Project, Denver,, Colorado,
December 1965, Appendix B.
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45
ENGLEWOOD WASTEWATER TREATMENT PLANT
ENGLEWOOD, COLORADO
A. INTRODUCTION
The Englewood wastewater treatment plant is located on the South
Platte River (RM 325.1) and serves a population of approximately 63,000
persons. Except for chlorination, the high-rate trickling filter plant
is divided into two separate sections: the first section was constructed
in 1954; the second, in 1961. Chlorination was added in 1966. The plant
is manned continuously.
A study, conducted in 1964,— revealed that the plant was serving
a population of approximately 55,000. The BOD removal efficiency was
82 percent with approximately 715 Ib of BOD/day being discharged to the
South Platte River.
A survey, conducted by the National Field Investigations Center-
Denver (EPA) from September 20 through 25, 1971, determined only waste
loads discharged into the South Platte River. Englewood Director of
Public Works, Charles Carroll, provided information and assistance.
B. WASTE TREATMENT FACILITIES
The design capacity of the Englewood plant is 8 mgd. The two sections
of the plant are identical in configuration and size and have the follow-
ing principal components [Figure 1]:
1. Preliminary treatment — grit chamber, bar screen, and comminutor;
2. Primary treatment •— one clarifier;
3. Secondary treatment — two high-rate trickling filters in parallel
and a clarifier;
-------
46
4. Digestion — primary and secondary digester; and
5. Disinfection ~ the effluent leaving each secondary clarifier
flows to a common chlorine contact chamber.
Laboratory analyses are routinely performed in order to determine
the quality of the wastewater. Analyses include: BOD, settleable solids,
suspended solids, total solids, chlorine residual, volatile acids, pH,
and alkalinity. In addition to these data, plant operating records also
include measured values of daily flow, gas production, and grit removal.
At the time of the 1971 survey the plant was being expanded to a
capacity of 12 mgd by the addition of a contact stabilization unit. Major
repairs were in progress on the lift stations, headworks, trickling filters,
and digesters. Sludge lines were being replaced. The City of Englewood
received permission from the Colorado Water Pollution Control Commission
to divert the total flow through one section of the plant while the re-
pairs and modifications were being made.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the effluent (before chlorination) were
collected, using SERCO automatic samplers; the samples were composited
on a flow weighted basis from measurements obtained at the headworks.
Composite samples of the effluent (after chlorination) were collected
by plant personnel. Temperature, pH, and conductivity were measured
periodically. Grab samples of the effluent were collected for bacterio-
logical analyses and measured for chlorine residual. [Chemical and
bacteriological data are summarized in Tables 1 and 2.]
-------
INFLVENT
INFLUENT
PRELIMINARY TREATMENT
PRELIMINARY TREATMENT
©_
/ SECONDARY \
"I CLARIFIER I
KEY
WATER
SLUDGE
SLUBGE TO
ANAERDBIC
DIGESTER
AND THEN TO
DRYING BEDS
SLUDGE TO
ANAEROBIC^"
DIGESTER
AND THEN TO
DRYING BEDS
EFFLUENT
SOUTH PLATTE RIVER
/ SECONDARY\
1
CHLORINE CONTACT
CHAMBER
a
or
> i
?. H
LOCATION MAP
NOT TO SCALE
-J
a.
0
w
BATES ST
ENGLEWOOD
PLANT
Figure 1. Waste water Treatment Plant. En^iewood
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
ENGLEWOOD WASTEWATER TREATMENT FACILITY
SEPTEMBER 21-25, 1971
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
TOC (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
NH3 (mg/1)
K -N (mg/1)
N02-N03 (mg/1)
Total P (mg/1)
Effluent before
Range
7.1-8.9
14-18
1,050-1,800
80-90
60-200
870-900
120-150
16-18
23-26
0.03-0.96
6.6-8.0
Chlorination
Average
87
165
890
135
17
25
0.53
7.4
Effluent after
Range
8.2-8.8
7.4-8.6
15-19
1,200-1,500
60-70
50-60
870-890
9<£'
15-17
22-23
0.73-0.96
5.6-7.0
Chlorination
Average
8.6
63
53
880
16
22
0.86
6.1
-p-
a/ Analyses for BOD, TOC, total solids, and suspended solids were performed on composite samples.
b/ This is a single sample.
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48
TABLE 2
BACTERIOLOGICAL RESULTS
ENGLEWOOD WASTEWATER TREATMENT FACILITY
Date
September 21, 1971
September 22, 1971
September 23, 1971
Time
0815
1140
1430
0925
1305
2000
0625
1525
Total
Coliform
Count/100 ml
<10
310,000
19,000
160,000
>800S000
53,000
5,700
1,300
Fecal
Coliform
Count/100 ml
<10
2,200
120
1,100
6,000
200
360
<10
Chlorine
Residual
mg/1
0.2
0.0
0.9
0.2
0.3
-------
49
The average BOD and suspended solids load discharged to the river
were equivalent to 4,530 and 6,340 pounds per day, respectively. Disin-
fection was inadequate for part of the time [Table 2].
Currently being proposed is a regional treatment facility designed
21
to serve the communities of Englewood and Littleton.— Though only in
the discussion stage, the proposal calls for continued operation of the
existing Littleton plant (4.5 tngd capacity) plus re-activation of the
original Littleton facility (one mgd). Flows in excess of 5.5 mgd would
be diverted to the Englewood municipal facility. All future expansion
would be at the Englewood site.
*
Maintenance of adequate dissolved oxygen, i.e. 6.0 mg/1, at low
flow conditions requires the wastewater effluent to contain a BOD no
greater than 25 mg/1.
D. SUMMARY AND CONCLUSIONS
1. The Englewood plant was undergoing modifications and expansion
during the September, 1971, survey. Thus, adequate treatment was not
provided — the effluent BOD was more than six times that observed during
studies conducted in 1967. Disinfection was adequate a portion of the
time.
2. To meet water quality standards at low flow conditions will re-
quire that the Englewood facility produce an effluent biochemical oxygen
demand containing no greater than 25 mg/1.
* This is the State of Colorado dissolved oxygen standard for cold
water fisheries.
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50
E. RECOMMENDATIONS
It ±3 recommended that:
1. The biochemical oxygen demand and suspended solids in the Engle-
wood wastewater effluent not exceed 25 mg/1 or 2500 Ib/day of each (at
12 mgd), whichever is less.
2. The effluent contain no greater than 1000 fecal coliform
bacteria/100 ml.
F. REFERENCES
I/ Municipal Waste Report3 Metropolitan Denver Areas South Platte
River Basin 3 U. S. Department of Health, Education, and Welfare,
Public Health Service, Division of Water Supply and Pollution
Control, South Platte River Basin Project, Denver, Colorado,
December, 1965. Appendix B.
2] Littleton and Englewood Look at Joint Sewer Project 3 Littleton
Independent, 84th year, No. 45, Littleton, Colorado, Thursday,
May 25, 1972.
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51
FORT COLLINS WASTEWATER TREATMENT PLANTS
FORT COLLINS, COLORADO
A. INTRODUCTION
The City of Fort Collins operates two wastewater treatment plants.
Plant No. 1, located on the Cache la Poudre River (RM 249.0/44.1), is a
high-rate trickling filter plant designed for 4.5 mgd. The plant was
originally constructed in 1948, expanded in 1958 and again in 1961.
Chlorination was added in 1968. Plant No. 2, also located on the Cache la
Poudre River (RM 249.0/40.2), is a conventional activated sludge plant
designed for 4.8 mgd. It was constructed in 1968 with an EPA grant, at
a cost of 1.2 million dollars.
The superintendent of sewers and a laboratory technician serve both
Plants No. 1 and No. 2. The staff for each plant includes a chief oper-
ator, two operators, and two utility men. Both plants are manned con-
tinuously. The operating budget in 1971 for these two plants was $158,000.
Studies conducted in 1965 and 1966,— indicate that the BOD removal
efficiencies for Plant No. 1 varied from 65 percent to 77 percent.
Disinfection of the effluent was not provided. Additional waste treat-
ment and adequate disinfection was recommended at that time.
Both plants were evaluated by the National Field Investigations
Center-Denver from January 31 through February 2, 1972. Charles Liquin,
Director of Public Works, provided information and assistance.
B. WASTE TREATMENT FACILITIES
1. Fort Collins Plant No. 1 - The plant is designed for 4.5 mgd.
The principal components of the plant [Figure 1] are:
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52
a) preliminary treatment — bar screen, grit chamber and comminutor;
b) primary treatment — two clarifiers (each 85 ft in diameter and
10.5 ft deep) designed for a detention time of 2.4 hr at a flow
of 4.5 mgd;
c) secondary treatment — high-rate trickling filter (130 ft in
diameter and 5 ft, 9 in deep) and a rectangular clarifier (63 ft
wide, 105 ft long, and 805 ft deep) designed for a maximum flow
of 8.9 mgd;
d) disinfection — chlorine contact chamber with a detention time
of 15 minutes at 4.5 mgd; and
e) digestion — two primary and two secondary anaerobic digesters;
digested sludge is removed to drying beds.
2. Fort Collins Plant No. 2 - The plant is designed for 4.8 mgd.
The principal components of the plant [Figure 2] are:
a) preliminary treatment — bar screen, grit chamber, and comminutor;
b) primary treatment — two clarifiers (65 ft in diameter and 8 ft
deep) with detention time of 1.8 hr at design flow;
c) secondary treatment — activated sludge unit, with two aeration
tanks (each with a volume of 450,000 gal) that each have
mechanical aerators and a detention time of 4 hr at design flow,
and two clarifiers (65 ft in diameter and 8 ft deep) with deten-
tion time of 1,8 hr at design flow;
d) disinfection — chlorine contact chamber with a detention time
of 15 minutes at design flow; and
e) digestion — two-stage anaerobic digestion, digested sludge is
removed to drying beds.
-------
INFLUENT
PRELIMINARY TREATHEBT
SLII6E TS T«e-STASE
ANAESiSiC BI6ESTEIS
US TtiEH Tl
IITI99C BEBS
KEY
WATER
SLUDGE
P9I1AIY
CLAIIFICATItN
ICIAIIFICATION!
T1ICKLING
FILTEI
RECIICULAT16H TO
PRIMARY CLABIFIERS
SLUDJE_TJ I
PR'IMARY CLARIFIERS
LOCATION MAP
CNLORINE
CONTACT
CNAMIER
CACHE
LA POU
FORT
COLLINS
PLANT N0.1
EFFLUENT
CACHE LA POHIRE RIVER
NOT TO SCALE
Figure 1. Wastewaler Treatment Plant No.]' Fort Collins
-------
IHFLIEHT
PIEUIfiiHAiY TSEATiJEiT
SLUDGE TO TWO-STAGE
^ANAEROBIC DIGESTERS
ANB TNEN TO
BRYING IE8S
KEY
PRIMARY
CLA1IFIEIS
WASTE
ASTIVATEI
SLHI&E
AESATION
UNITS (2)
SECONDARY
CLARIFfEIS
SECONDA1V
CLARIFIE8S
LOCATION MAP
CACHE LA POUDRE
CHLORINE
CONTACT
CNAilEI
FORT
COLLINS
PLANT NO.2
EFFLUENT
CACNE LA POHIRE RIVER
NOT TO SCALE
Figure 2. Wastewater Treatment Plant No.2 . F@rt Caitias
-------
53
Laboratory facilities have been provided at Plant No. 2. Influent
and effluent analysis (BOD, pH, settleable solids, and suspended solids)
are run for both Plant No. 1 and Plant No. 2 in this laboratory. In
addition chlorine residuals, volatile acids, and alkalinity are also
checked periodically. Process control analysis on the activated sludge
unit, Plant No. 2, are run daily.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the influent and effluent (before chlorin-
ation) were collected at both plants during January 31 through February 2,
1972. The samples were collected using SERCO automatic samplers and com-
posited on a flow weighted basis from measurements taken at the headworks.
Temperature, pH, and conductivity were measured periodically at each
sampling location. Periodic grab samples were collected for bacteriological
analyses and chlorine residual measurements. [The results of the chemical
and bacteriological analyses are contained in Tables 1-4.]
At Plant No. 1 BOD removal efficiency ranged from 66 to 75 percent,
below the minimum required by the State of Colorado. The efficiency of
suspended solids removal ranged from 0 to 96 percent [Table 1]. Flows
varied from 2.3 to 5.2 mgd reaching a level of 15 percent above design
capacity at peak flows. The peak flows would cause solids to carry over
the clarifiers thereby reducing overall plant efficiency. Disinfection
of the effluent was not adequate as chlorine residuals varied from 0.0 to
0.5 mg/1 [Table 3].
Plant No. 2 was providing adequate treatment under State criteria.
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
FORT COLLINS WASTEWATER TREATMENT FACILITY NO. 1
JANUARY 31-FEBRUARY 2, 1972
Ln
.0
a/
Parameter
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
6.9-7.5
10-11.5
600-2,850
185-200 193
341-777 609
872-1,440 1,164
202-941 454
Effluent
Range
3.62-3.98
6.9-7.4
8-11
600-1,000
52-66
135-195
378-586
41-240
Average
3.86
59
158
495
110
Percent
Resaoval
66-75
60-79
40-68
0-96
&l Analyses for BOD, COD, total solids, and suspended solids were perforated oa composite samples.
-------
TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
FORT COLLINS WASTEWATER TREATMENT FACILITY NO. 2
JANUARY 31-FEBRUARY 2, 1972
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (^mhos/cm)
BOD (rag /I)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
7.1-9.5
10-13
500-800
200-230 218
795-955 888
609-793 717
324-376 346
Effluent
Range
3.4-4.1
6.1-6.8
8.5-9.0
580-625
35-42
71-168
315-353
21-42
Average
3.9
39
132
339
30
Percent
Removal
79-84
79-83
43-60
89-93
a/ Analyses of BOD, COD, total solids, and suspended solids were performed on composite samples,
Ul
Ol
-------
V..3LE
BACTERIOLOGICAL RESULTS
PORT COLLINS WASTEWAIER TREATMENT FACILITY NO, 1
January 31, 1972
February 1, 1972
February 2, 1972
Time
1030
1500
0930
1300
0925
1435
Total
Colif orci
Couut/100 ml
Fecal
Coliform
Count/I00 H
410?000
430,000
81,000
130 , 000
74S000
59,000
500
300
620
2,000
Chlorine
Residual
m;
0.5
0,1
0.0
0.1
0.3
BACTERIOLOGICAL RESULTS
FORT COLLINS WASTEWATER TREATMENT FACILITY NO. 2
Date
Time
Total
Colifortn
Count/100 ml
Fecal
Coliform
Count/100 ml
Chlorine
Residual
January 31, 1972
February ls 1972
February 2, 1972
1135
1525
0900
1335
0850
1415
3,200
5,000
270
<100
70
2,000
100
<100
4
<4
0.9
0.5
0.9
0.9
<1,000
-------
57
BOD removal efficiencies ranged from 79 to 84 percent (average of 82
percent). Although the chlorine residuals were less than 1 mg/1 (range
of 0.5 to 0.9 disinfection of the effluent was adequate (fecal coliform
bacteria density ranged from <4 to <1,000/100 ml).
21
A stream survey in September 1971— showed that the wastewater dis-
charged by the two Fort Collins treatment plants degraded the water quality
and stream bed environment of the Cache la Poudre River. Improved treat-
ment at these plants appears necessary.
In determining pollution control requirements the low flow conditions
were examined for the Cache la Poudre River for the period, 1961-1970. The
seven-day, ten-year low flow downstream from Fort Collins was 24 cfs before
receiving wastes from the two municipal plants. To prevent violation of
water quality standards in the river (i.e., to maintain a DO concentration
of not less than 5 mg/1) requires that the effluent from each of these
two treatment plants contain no more than 25 mg/1 (1000 Ib/day) each of
BOD and suspended solids.
D. SUMMARY AND CONCLUSIONS
1, The BOD removal efficiency at Fort Collins Plant No. 1 did not
meet the Colorado requirements for secondary treatment.
2. Disinfection of the effluent was not adequate at Plant No. 1.
3. Water quality degradation occurred downstream from the discharges
of the two plants.
4. Low flow conditions require that the BOD and suspended solids
concentrations in the effluent at each plant not exceed 25 mg/1 each or
1000 Ib/day each at design flow to prevent water quality degradation
in the Cache la Poudre River.
-------
It is recoromeiided that:
i. The treatment facilities at each plant be upgraded to provide
that the biochemical oxygen deaand and suspended solids in the effluents
not exceed 25 mg/1 or 1S000 Ib/day of each whichever is less.
2, Adequate disinfection of the Plant No. 1 effluent be provided.
F, REFERE_NCE_S
I/ Status of Municipal Waste Treatment in the South Platte Biver
Basin., Colorados 1964-87s U. S, Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967,
2j WateT Quality Investigations in the South Platte River Basin,
Colorado3 1971-72s National Field Investigations Center-Denver
and Region VIII, Denver, Colorado, April 1972.
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59
FORT LUPTON WASTEWATER TREATMENT PLANT
FORT LUPTON, COLORADO
A. INTRODUCTION
The Fort Lupton treatment plant serves a permanent population of
approximately 2,600 people and an additional 1,400 people during the
summer and fall months. Discharge from this plant is to the South
Platte River (RM 287.6). The plant is manned approximately two hours/
day by a part-time operator. Industrial wastewater from the Fort
Lupton Canning Company is also discharged to the municipal sewer during
summer months.
In 1967— a single grab sample, collected from the combined lagoon
effluent, contained 20 rng/1 of BOD and 21 mg/1 of suspended solids.
An in-plant survey was conducted during the period September 27-29,
1971. Howard McWilliams, Plant Operator, provided information and
assistance.
B. WASTE TREATMENT FACILITIES
The treatment facility [Figure 1] consists of two lagoons operated
in parallel. Each lagoon has an area of 14.5 acres and is operated at
a depth of 5 ft. The retention time is approximately 150 days at present
flow. Effluent from the canning company passes through screens prior to
being discharged into the municipal sewer.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
A grab sample of the combined effluent from each lagoon was collected
each day, September 28, 29, and 30, 1971. Temperature, pH, and conductivity
-------
60
were measured each time & sample was collected. Grab samples were also
collected for bacteriological analysis. Visual observation showed adequate
maintenance of the lagoon banks and the characteristic green water color
was indicative of a properly operating lagoon.
The survey data [Table 1] indicate that the effluent BOD ranged from
20 to 40 rag/1, (average 30 mg/1 or 8 Ib/day).
A review of the bacteriological results [Table 2] reveals that the
wastewater receives adequate disinfection under State requirements. At
present flow the lagoons provide 150 days detention time.
D. SUMMARY AND CONCLUSIONS
1. The treatment facility provides adequate treatment and disin-
fection of wastewaters under existing State requirements.
2. Wastes from the Fort Lupton Canning Company were not causing
any adverse effects upon the operation of the lagoons.
E. REFERENCE
I/ Status of Municipal Waste Treatment in the South Platte River Basin,
Colorado, 1964-196?, U. S. Department of the Interior, Federal Water
Pollution Control Administration, South Platte River Basin Project,
December 1967.
-------
_--*__* -X----f
I
*
15 ACIE
LA6I6N
-ks
*
i
EFFLIUT
15 ACRE
LA800N
r—-K
#
I
I
COLO. 52
PBiPIBS
STATIIH
F8RT UPTON
lAl
NOT Til SCALE
Figure 1. Wastewater Treataeit Plant- F«rt Lapt«a
-------
61
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
FORT LUPTON WASTEWATER TREATMENT FACILITY
SEPTEMBER 27-30, 1971
Parameter
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
TOG (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Total N (mg/1)
NH3 (mg/1)
N02 + N03 (mg/1)
Total Phosphorus (mg/1)
Effluent
Range
8.8-9.6
12.0-14.0
2,200-2,400
20-40
50-60
1,640-1,670
80-140
8.0-22
0.5-1.1
0.12-0.18
3.0-3.4
Average
0.032-7
30
53
1,660
116
12.8
0.9
1.5
3.3
a/ This is a single value.
-------
TABLE 2
BACTERIOLOGICAL RESULTS
FORT LUPTON WASTEWATER TREATMENT FACILITY
Sept<
Date
ifflber 27, 1971
September 28, 1971
Time
1445
0815
1645
Effluent from
Total Coliform
Count/ 100 ml
2,700
190,000
>80,000
North Lagoon
Fecal Coliform
Count/100 ml
1,900
18,000
16,000
Effluent from
Total Coliform
Count/100 ml
23,000
35S000
779000
South Lagoon
Fecal Colifonm
Count/ 100 ml
3S100
5,100
33,000
September 29, 1971
1040
>80,OOQ
8,200
438000
12,000
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63
FORT MORGAN WASTEWATER TREATMENT PLANT
FORT MORGAN, COLORADO
A. INTRODUCTION
The Fort Morgan wastewater treatment plant is located on the South
Platte River (KM 195.2). The plant presently serves a population of
about 7,600 people together with wastewater (approximately 1 mgd) dis-
charged by American Beef Packers, Inc. The plant is manned eight hours/
day by one operator. The primary units were constructed in 1956 with
the addition of secondary treatment facilities in 1961.
In 1966,— the Fort Morgan plant was treating an average flow of
1.5 mgd, below the design capacity of 2.0 mgd. The BOD removal efficiency
was 87 percent. There was no provision for disinfection of the effluent.
A 1972 in-plant survey was conducted during the period, January 25
through 29. Jack Odor, city engineer; Henry Sells, Jr., plant superin-
tendent; and Cecil Osborne, consulting engineer, provided information
and assistance.
B. WASTE TREATMENT FACILITIES
The present facilities are designed for a capacity of 2.0 mgd and
a BOD loading of 4500 Ib/day. The principal components [Figure 1] of
the plant are:
1. Preliminary treatment — two grit chambers, bar screen, and two
comminutors with the grit chambers and bar screen cleaned manually;
2. Primary treatment — two clarifiers (one 45 ft in diameter and
9 ft deep and the other 60 ft in diameter and 10 ft deep) with
-------
64
a surface overflow rate (based on average flwv'v of 575 gal/ft
per day and detention time of three hours;
3. Secondary treatment — two high-rate trickling filters operated
in series (one 88 ft in diameter with 7 ft of rock media and
the other 100 ft in diameter and 6 ft of rock a^dia)3 and
clarifier (52 ft in diameter and 10 ft deep) with a surface over-
2
flow rate of 900 gpd/ft and detention £lae of 1.5 hr; and
4. Digestion — two anaerobic digesters (one 45 ft in diameter and
23 ft deep and the other 65 ft in diameter and 28 ft deep) that
are heated,
Construction of additional secondary facilities was underway with
financing provided by the City of Fort Morgan and American Beef Packers,
Inc. Because of a lack of funds the construction had been delayed.
The additional facilities [Figure 1] include:
1. Two high-rate trickling filters (each 120 ft in diameter aad
7 ft deep) to be operated in series;
2. Secondary clarifier (60 ft in diameter and 10 ft deep); and
3. Chlorination facilities including a contact chamber (20 ft by
40 ft by 8 ft) with a detention time of 23 minutes at a peak
flow of 3 mgd. (Additional detention will be provided by the
long outfall line to the South Platte River.)
Based on Colorado design criteria the new facility will increase tbe
level of organic loading by 7900 Ib of BOD/day to a total of 12,400 Ib
of BOD/day.
-------
PIELINIHAIY TIEATMENT
FORT MORGAN
PLANT j
J
FORT MORGAN
LOCATION MAP NOT TO SCALE
EFFLUENT
SUTN PLATTE RIVEi
Figure 1. Wastewater Treatment PlaBt , Fart RUrgaa
-------
65
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composite samples of the influent and effluent were col-
lected using SERCO automatic samplers on the dates, January 25, 26, and
28, 1972. All samples were composited on the basis of time. Temperature,
pH, and conductivity were measured periodically at each sampling location
and grab samples were collected for bacteriological analyses, Grab samples
of the effluent from the American Beef Packers, Inc. were also collected
daily for chemical analyses [Table 1].
The American Beef Packers, Inc. process from 1,000 to 1,400 head of
beef daily, five days per week. Process wastewater, prior to being dis-
charged to the municipal sewers, is given primary treatment. Water used
to clean stock holding pens is discharged to the municipal sewers with-
out any pretreatment. The estimated BOD load from the packing plant,
calculated on grab sample analyses, was 13,700 Ib/day. This comprises
90 percent of the total influent load (14,800 Ib) received by the Fort
Morgan plant.
The organic and hydraulic capacity of the Fort Morgan plant was ex-
ceeded during the 1972 survey. With the addition of two new trickling
filters the organic loading of the plant will be increased to approxi-
mately 12,400 Ib BOD/day. The present loading is in excess of the ex-
panded capacity.
Efficiencies of BOD and suspended solids removal [Table 2] ranged
from 63-77 percent and 72-92 percent, respectively. The high strength
waste from the packing company precludes proper operation of this muni-
cipal plant. The levels of BOD in the plant effluent, 160-220 mg/1,
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66
OF FIELD AND ANALYTICAL HSULXS
AFRICAN BEEF PACKI1S s FORT MJ1GM, COLORADO
Paraaeter—
a/ All analyses were conductad ©ia grab
BOD (tag/1) lf]
COD (ng/1) 2,1SO-68460 3.900
Total Solid* (mg/1) 7,630-53,700 31,400
Suspended Solid® (ag/1) 3,140-29,800 12,600
-------
TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
FORT MORGAN WASTEWATER TREATMENT FACILITY
JANUARY 26-29, 1972
Parameter—
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
7.5-8.2
19-22
1,400-4,000
600-790 697
1,130-3,990 2,160
3,380-4,070 3,820
340-1,570 834
Effluent
Range
2.30-2.82
7.5-7.8
10-15.5
2,400-4,000
160-220
291-439
2,860-2,950
66-129
Average
2.55
190
383
2,900
94
Percent
Removal
63-77
61-93
15-28
72-92
a/ Analyses of BOD, COD, total solids, and suspended solids are performed on composite samples,
-------
68
are excessive. The BOD and suspended solids levels should be about
30 mg/1. Additional pre-treated by the packing company (level of
250 mg/1 each of BOD and suspended solids in the effluent), expanded
facilities, and improved operation at the Fort Morgan municipal plant
are required to achieve the 30 mg/1 level.
Fecal-coliform bacteria densities ranged from 310,000-720,000/100 ml
[Table 3] because disinfection of the effluent by chlorlnation was not
being practiced.
During the survey the following observations were made:
1. Grit chambers were not operated adequately. The plant has two
grit chambers that are employed in an alternating manner, with
only one unit in service at a time. A single grit chamber is
used for one week and then the flow is diverted through the
other unit while the first is cleaned. However, because of the
large amount of grit carried by the plant influent, the grit
chamber fills rapidly allowing the incoming grit to carry over
into the primary clarifier. The grit is then pumped with the
sludge to the digestor, reducing the effective digestor capacity.
In addition, wastewater trapped within the grit filled chamber
was pumped to a manhole that discharges it to the South Flatte
River. Grit removed from the chamber is spread within the
municipal plant area.
2. No continous flow recording instruments were installed at the
municipal plant. The average daily flow was obtained by aver-
aging five staff gage readings taken from a Parshall flume.
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69
TABLE 3
BACTERIOLOGICAL RESULTS
FORT MORGAN WASTEWATER TREATMENT FACILITY
Date
January 26, 1972
January 27, 1972
January 28, 1972
Time
1215
1315
1145
1215
1045
1215
Total
Colif orm
Count/100 ml
2,700,000
1,700,000
5,300,000
9,100,000
3,000,000
3,500,000
Fecal
Coliform
Count/100 ml
720,000
550,000
310,000
640,000
380,000
580,000
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70
3. The municipal plant operators have not received any formal
training in treatment plant operation.
4. Routine maintenance and operation of the municipal facilities
were inadequate.
5. Laboratory facilities were provided for the performance of
chemical tests of wastewater quality. Analyses were being
performed to determine the quality of the influent and effluent
from American Beef Packers9 Inc. Tests performed daily include
BOD and settleable solids. Additional laboratory analyses are
required to insure efficient operation of the municipal treat-
ment facilities.,
D. SUMMARY AND CONCLUSIONS
1. The Fort Morgan wastewater treatment plant was both hydraulically
and organically overloaded. It did not meet the State of Colorado re-
quirements for secondary treatment and disinfection. Moreover, 80 per-
cent BOD removal from the wastewater load received would be inadequate.
2. American Beef Packers, Inc. provides primary treatment to their
process wastewaters; but does not give any treatment to stock pen
washings. The high strength wastes from this plant constitutes the ma-
jority (90 percent) of the waste load entering the Fort Morgan plant.
American Beef Packers, Inc. is the cause of the Fort Morgan plant's
organic overloading.
E. RECOMMENDATIONS
It is recommended that:
1. Disinfection of the effluent from the Fort Morgan wastewater
plant be implemented immediately.
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71
2. The effluent contain no more than 30 mg/1 each of suspended
solids and biochemical oxygen demand.
3. The present expansion program be completed by January 1, 1973.
4. The wastewaters from the American Beef Packers, Inc. be pre-
treated such that the biochemical oxygen demand and suspended solids
levels are comparable to domestic sewage (250 mg/1), with the total loads
of each not to exceed 2100 Ib/day.
5. The municipal plant install an adequate flow-recording device
by January 1, 1973.
6. Operation be modified to provide for better grit removal; waste-
water removed from the grit chamber be diverted to the headworks of the
plant.
7. The plant operators receive training by attendance at an operater
school and by on-the-job training.
F. REFERENCE
\J Status of Municipal Waste Treatment in the South Platte River
Basin, Colorado, 1964-67, U. S. Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967.
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72
-------
73
JULESBURG WASTEWATER TREATMENT PLANT
JULESBURG, COLORADO
A. INTRODUCTION
The Julesburg wastewater treatment plant serves approximately 1,850
people. The effluent from the standard rate trickling filter plant flows
through a polishing pond to the South Platte River (RM 86.9). The ori-
ginal wastewater treatment facility was constructed in 1958, and designed
for a capacity of 0.295 mgd; the polishing pond was added in 1968.
In 1966— the Julesburg wastewater treatment facility had major
operational problems that resulted in the discharge of raw sewage and
primary clarifier effluent to the South Platte River. Disinfection of
the effluent was not being provided.
An in-plant survey was conducted during a three-day period, October
3-5, 1971. Dean Gilliard, city clerk, provided information and assistance.
B. WASTE TREATMENT FACILITIES
The principal components of the system [Figure 1] are:
1. Preliminary treatment — bar screen, grit chamber, and comminutor;
2. Primary treatment — rectangular clarifier (12 ft by 44 ft, with
a depth of 7 ft) which has, at design flow, a detention time
2
of two hours, surface loading rate of 200 gpd/ft , and over-
flow rate of 10 gpm/ft;
3. Secondary treatment — trickling filter (72 ft in diameter and
7 ft deep) and rectangular clarifier (8 ft by 44 ft and a 7 ft
2
depth) that is designed for a surface loading rate of 838 gpd/ft ;
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74
4. Disinfection and polishing — lagoon (490 ft by 229 ft) with an
operating depth that varies from 4 to 7 ft providing a detention
time of 21 days at the greatest depth; and
5. Digestion — one anaerobic digester (40 ft in diameter by 24 ft
deep); digested sludge is placed in drying beds.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the influent and the effluent were collected
using SERCO automatic samplers. Samples were composited on a flow weighted
basis from measurements obtained at the headworks. Periodic measurements
were made of temperature, pH, and conductivity. Grab samples were also
collected periodically for bacteriological analyses.
During the survey, the following visual observations were made.
1. The grit chamber, the wet well, and the weirs on the primary and
secondary clarifiers had not been cleaned for some period.
2. The standard-rate trickling filter is not receiving sufficient
flow to rotate the arms properly. Re-circulation was not provided and
biota growth on the rock media was minimal.
3. The lagoon has not been maintained. The vegetation on the
lagoon banks should be cut to prevent insect problems.
4. The influent and effluent discharge lines are improperly placed
in the lagoon. With the present system there is a potential for short
circuiting of flow, thus reducing the effective detention time of the
lagoon.
5. The city clerk also functions as operator, but has not received
formal training in the operation of this facility. It is estimated that
-------
IHFLHEHT
PIEUMtMAiY TiEATMEMT
LOCATION MAP
JULESBURG
i---|
i_ J
JULESBURG
PLANT
NOT TO SCALE
PRIiARY
CLARIFIER l\
]
LAfilON
BY PASS TO SOUTH PLATTE IIVER
EFFL8ENT
SOUTH PLATTE RIVER
KEY
WATER •
SLIIfiE- —
Figure 1. Wastewaler Treatment Plant , Jvlesbiirg
-------
75
only ten hours per week Is devoted to operation and routine maintenance
of the plant.
6. Essentially no laboratory equipment is available at this plant.
Limited laboratory analysis are performed periodically by the Northeast
Colorado Health Department.
The 1971 survey data [Table 1] shows that the BOD removal efficiency
varied from 43 to 84 percent, with an average of 69 percent. The efficiency
was equal to or greater than 80 percent on two days of the survey. On
one of the days a lift station malfunctioned, causing a back-up of waste-
water in the sewers. After the station became operable, a surge of heavy
flow into the plant caused "scouring" in the primary and secondary
clarifiers. As noted earlier, the short circuiting in the lagoon is
possible because of relative locations of the influent and effluent lines.
The inadequacy in the present disinfection procedures is reflected
by the total and fecal coliform bacteria densities [Table 2] that ranged
from 43,000 to 830,000/100 ml and from 1,900 to 260,000/100 ml, respec-
tively . The State of Colorado requires a minimum of 30 days retention
time if polishing ponds follow mechanical plants and are used for dis-
infection. If the lagoon is operated at the maximum depth of 7 ft, the
theoretical detention time is 21 days.
D. SUMMARY AND CONCLUSIONS
1. The BOD removal efficiency was greater than 80 percent two of
the three days sampled. The removal efficiency dropped to 43 percent on
the day a lift station malfunctioned.
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
JULESBURG WASTEWATER TREATMENT FACILITY
OCTOBER 3-5, 1971
a/
Parameter-
Flow (tngd )
pH (S.U.)
Temperature (°C)
Conductivity
(ymhos/cm)
BOD (mg/1)
TOC (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Total N (mg/1)
NH „ (mg / 1 )
NO,, + NO (ng/1)
Total P (mg/1)
Influent Effluent
Range Average Range Average
0.187-0.215 0.200
7.8-8.7 7.9-8.3
11.0-21.0 10.5-15.5
1,400-2,600 1,700-1,900
140-180 155 30-80 45
200-620 360 50-60 57
1,410 1,470
690 60
18-22 20
10-20 13
0.16-0,54 0.38
8-11 9
Percent
Removal
43-84
75-90
a./ Analyses of BOD, TOC, total solids, suspended solids. Total N, NH_, N02 + NO.., and Total P were
performed on composite samples.
-------
77
TABLE 2
BACTERIOLOGICAL RESULTS
JULESBURG WASTEWATER TREATMENT FACILITY
Date
September 27, 1971
September 28, 1971
September 29, 1971
October 3, 1971
October 4, 1971
October 5, 1971
Time
0815
1220
0755
1220
0640
1030
0745
1425
0835
1440
0840
Total
Coliform
Count/100 ml
530,000
400,000
680,000
>800,000
>80,000
>80,000
550,000
43,000
830,000
>80,000
600,000
Fecal
Coliform
Count/ 100 ml
57,000
20,000
260,000
41,000
54,000
34,000
88,000
20,000
1,900
12,000
58,000
-------
2, Adequate disinfection was not provided.
3. Operation and maintenance of the plant was inadequate. Operator
training is needed.
RECOMMENDATIONS
It is recommended that:
1. Operation of the plant and sewer system be improved to provide an
effluent containing biochemical oxygen demand and suspended solids each no
more than. 30 mg/1.
2, The effluent receive adequate disinfection and contain no more
than 1000 fecal collform bacteria/100 ml at any time.
3. The plant operator be provided training in the operation and
maintenance of the plant by attendance at an operator school and be pro-
vided on-the-job taining.
4. Operation of the trickling filter be modified to include recir-
culation of effluent.
5. Maintenance practices be improved including proper care of lift
stations and clarifiers.
F. REFERENCE
17 Status of Municipal Waste Treatment in the South Platte River
Basin, Colorado., 1964-673 U. S „ Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967.
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79
LITTLETON WASTE TREATMENT PLANT
LITTLETON, COLORADO
A. INTRODUCTION
The Littleton plant, located on the South Platte River (R>1 327.6),
serves, at the present time, a population of at least 26,000 persons.
The municipal facility is currently staffed by a plant superintendent,
an assistant plant superintendent who also performs all the laboratory
analysis, and three plant operators. It is manned continuously- The
municipal plant (capacity, 4.5 mgd) was constructed in 1955 and 1959,
replacing a facility which had one mgd wastewater treatment capacity.
An evaluation of the plant, in 1964,— revealed that adequate sec-
ondary treatment was being provided, except for disinfection. Infiltration,
during the summer months, in the older portion of the collection system
caused flows to increase, by approximately one mgd, and become greater
than those in the winter months.
Chlorination facilities were installed in this plant and became
operational by July 1968.
The plant was again evaluated from September 20 through 25, 1971,
in order to determine treatment effectiveness. Gail Mullis, plant super-
intendent, provided information and assistance.
B. WASTE TREATMENT FACILITIES
The present treatment facilities [Figure 1] consist of the following:
1. Preliminary treatment — grit chamber, bar screen, and comminutor.
2. Primary treatment — clarifier (80 ft in diameter, 8 ft side
water depth (SWD)) that is designed for a detention time of two
hours at 4.5 mgd.
-------
80
3. Secondary treatment — two high-rate trickling filters (each 100
ft in diameter with one 5.5 ft and the other 5 ft depth) designed
for a hydraulic capacity of 11.9 mgd and an organic capacity
equivalent to approximately 4,600 Ib BOD/day; one clarifier
(100 ft in diameter by 8.5 ft SWD) designed for about 6.9 mgd.
4. Disinfection — chlorination in the outfall line (0.5 mile in
length), providing contact time of 15 min at 5.5 mgd.
5. Sludge digestion — two-stage anaerobic digesters; digested
sludge is removed to drying beds.
Laboratory analyses are routinely performed on both the influent
and effluent for BOD and suspended, settleable, and volatile-suspended
solids. The pH, volatile acids, and alkalinity measurements are made on
the digested sludge. Complete records are maintained of the operational
performance of this municipal waste treatment plant.
Additional treatment capacity, about one mgd, is available if the
City of Littleton were to employ the original facility, a trickling filter
plant, currently not in use.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the influent and the effluent before
chlorination were collected from September 21 through 24, 1971, using
SERCO automatic samplers. Samples of the effluent after chlorination
were collected manually by plant personnel over the same time period.
All samples were composited on a flow weighted basis. The pH, temper-
ature, and conductivity were measured periodically at all three points.
Grab samples of the effluent, at the point of discharge to the South
-------
INFLUEKT
PBELIHIHARY TIEATSIEUT
/ PIIMARY \
I CLAIIFIEI I
SLHICE TS
AHAERBBIC
1IIESTESS
AMI TiEa T0
IITIHI
LOCATION MAP
/ SECONOAIY \
A CLARIFIEI I
KEY
WATER
SLUDGE
EFFL1ENT
CHLORINE C8NTACT
TIME PRIVIIEB BY
OUTFALL LINE TO
SOUTH PLATTE HIVE*
LITTLETON
PLANT
NOT TO SCALE
Figure 1. Wastewater Treatment Plant.Littleton
-------
81
Platte River, were collected for chlorine residual measurements and for
bacteriological analyses [Table 1].
A review of the data in Table 1 shows that chlorination was adequate
as fecal coliform bacteria densities were less than 1000/100 ml except
on one occasion (2600/100 ml).
The BOD removal efficiency was determined before and after chlori-
nation [Table 2]. Prior to chlorination the efficiency ranged from
73-82 percent; after chlorination the range was 75-80 percent. The State
of Colorado requires a minimum BOD removal of 80 percent. The suspended
solids removal efficiency averaged 64 percent after chlorination. As
mentioned previously, infiltration increases flows to the plant during
the summer months (plant records indicated average flows of 3.9 mgd in
January 1971 and of 4.8 mgd in July 1971). During the 1971 survey the
hydraulic load averaged 5.2 mgd, exceeding the plant capacity.
Currently being proposed is a regional treatment plant designed to
21
serve the communities of Littleton and Englewood.— Though only in the
discussion stage, the proposal calls for the continued operation of the
existing Littleton plant (4.5 mgd capacity) plus re-activation of the
original Littleton facility (one mgd). Flows in excess of these 5.5 mgd
would be diverted to the Englewood municipal facility, which is currently
being expanded to handle a flow of 12 mgd. (All future expansions would
be carried out at the site of the Englewood municipal treatment plant.)
Maintenance of adequate dissolved oxygen concentrations in the South
*
Platte River, i.e. 6.0 mg/1, at low flow conditions requires that the
effluent contain no more than 25 mg/1 BOD (based on assumed flow rate
of 25 cfs).
* This is the State of Colorado dissolved oxygen criterion for a cold
water fishery.
-------
BACTERIOLOGICAL RESULTS
LITTLETON WASTEWATER TREATMENT PLANT
Date
September 21, 1971
September 22S 1971
September 23, 1971
Time
0800
1120
1450
0900
1245
2045
0603
1500
Total
Coliform
Count/ 100 ami
59100
52,000
15,000
38,000
17,000
100,000
170
1,900
Fecal
Coliform
Count/ 100 ml
40
90
120
230
280
2,600
10
<10
Chlorine
Residual
______jag/l
>1.0
G«9
0.9
1.2
1,1
1.0
-------
TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
LITTLETON WASTEWATER TREATMENT FACILITY
SEPTEMBER 21-25, 1971
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (^mhos/cm)
BOD (mg/1)
TOC (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Settleable Solids (ml/1)
NH3 (mg/1)
K -N (mg/1)
N02-N03 (mg/1)
Total P (mg/1)
Influent
Range Average
7.15-7.6
15-19
950-1,800
150-170 158
80-210 118
830-1,000 885
140-710 353
5^
10-13 12
17-24 20
0.30-0.60 0.42
6.4-9.6 8.0
Effluent
Before Chlorination
Range Average
7.5-8.0
17-20
1,000-1,600
30-40 33
20-60 40
590-690 650
40
9.5-12 10.5
14-16 15
0.28-0.68 0.45
6.0-7.6 6.9
Effluent , , Removal
After Chlorination— Efficiency
Range Average before Cl7
4.75-5.63 5.24
7.3-7.6
14-19
700-1,500
30-40 35 73-82
30-50 40 33-75
700-710 705
50
11-12 11.5
15-17 16
0.27-7.2 0.50
6.4-7.8 7.1
Removal
Efficiency
after Cl2
75-80
44-67
64
a/ Analyses of BOD, TOC, total solids, suspended solids, and settleable solids were performed on composite samples.
b/ This saspling was by plant personnel.
c/ This is a single sample.
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84
D. SUMMARY AND CONCLUSIONS
I. The efficiency of BOD removal was less than the present minimum
value of 80 percent, as required by the State of Colorado. The weak
strength of the effluent (158 mg/1) was attributed to infiltration flows
which continue to be a problem at this plant during the summer months.
2. Disinfection was adequate since fecal eollfora bacteria levels
were reduced to less than 1,000/100 ml, with one exception.
3. The hydraulic capacity of the municipal plant was exceeded
during the time of the survey. Flows daring the winter months of 1971
approached design capacity. Plant records Indicated that 1971 summer
flows exceeded the hydraulic capacity.
4. General plant maintenance appeared adequate. Routine laboratory
analyses are performed, with complete records being maintained at the
plant.
E. RECOMMENDATIONS
It Is recommended that:
1. The biochemcial oxygen demand and suspended solids in the dis-
charge each not exceed 25 mg/1, or 1,140 Ib/day (at 5.5 mgd), whichever
is less.
2. The effluent contain no more than 1,000 fecal coliform bacteria/
100 ml.
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85
F. REFERENCES
I/ Municipal Waste Report, Metropolitan Denver Area., South Platte
River Basin, U. S. Department of Health, Education, and Welfare,
Public Health Service. Division of Water Supply and Pollution
Control, South Platte River Basin Project, Denver, Colorado.
December, 1965, Appendix B.
2J Littleton and Englewood Look at Joint Sewer Plant, Littleton,
(Colorado) Independent, No. 45, May 25, 1972.
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86
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87
LONGMONT WASTEWATER TREATMENT PLANT
LONGMONT, COLORADO
A. INTRODUCTION
The Longmont wastewater treatment facility, which is located on the
St. Vrain Creek (RM 270.0/22,3), serves a population of 23,000 people.
The plant is manned 12 hours/day by a superintendent, three operators
and one part-time laboratory technician. From August through December,
wastewater (1.3 mgd) is also received from Longmont Turkey Processors, Inc.
In 1964— the plant, which consists of a high-rate trickling filter
designed for 4.0 mgd, was not providing adequate treatment or disinfec-
tion. Interconnections between the sanitary sewers, sub-drains and storm
sewers permitted the entry of ground water and storm water into the
sanitary sewers. Domestic sewage was being discharged into St. Vrain
Creek through a storm drain.
An in-plant survey was conducted at the Longmont wastewater treat-
ment plant from January 31 to February 3, 1972. City Manager Gerald
Trotter, and Clark Coe, plant superintendent, provided information and
assistance.
B. WASTE TREATMENT FACILITIES
The treatment facility has a design capacity of 5.24 mgd, with pumping
capacity being the limiting factor. The facility consists of a high-rate
trickling filter plant (constructed in 1960) and an activated biofilter
(ABF) plant (constructed since 1966). This ABF plant can also be operated
as a high-rate trickling filter plant [Figure 1]. At the time of the 1972
-------
88
survey, the ABF plant was operating In the trickling filter mode. The
raw influent passes through preliminary treatment facilities, consisting
of an automatic bar screen and comminutor, and divides between the two
plants (57 percent is diverted to the trickling filter plant). The
principal components of the trickling filter plant are:
1. Primary treatment —- clarifier (85 ft in diameter and 8 ft deep) ;
2. Secondary treatment — trickling filter (with 17,000 cu ft rock
media) and a clarifier (80 ft in diameter and 8 ft deep); and
3. Disinfection — chlorine is added in the final clarifier,
although not in operation during the 1972 survey.
The principal components of the ABF plant are:
1. Primary treatment — clarifier (70 ft in diameter and 7.5 ft
deep) ;
2. Secondary treatment — ABF (with 17,000 cu ft of redwood as a
filter medium) and a clarifier (95 ft in diameter and 7.7 ft
deep) ; and
3. Disinfection — chlorine is added in the filter clarifier,
although not In operation during the survey.
The sludge generated in both plants is pumped first to a degritter
and then to a thickener (designed for a capacity of 0.6 mgd). The
thickened sludge is pumped either to a two-stage digester (with a volume
of 20,000 ft /digester) or to a centrifuge. Solids are then trucked to
the city dump.
An artesian well located on the plant site, near the headworks, dis-
charges water into the outfall line. The effluent from the trickling
-------
IHFLVEMT
"I
MELIIIINAIY TtiATilBT
h
HEW PLANT
PLAIT
LOCATION MAP
/ SEC6NBARY t
\ DISESTEI
GREAT WESTERN
I SUGAR CO.
CO.LO. /
COLO.
254
LONGMONT
PLANT
CENTRIFN6E
„„„]___
LAN! BISPSSAL
EFFLUENT
ST.VRAIN CREEK
NOT TO SCALE
-SLUBSE
-WATE1
Figure I. Wastewater Treatment PU«l
-------
89
filter and AEF plants mixes with the well water, and the combined waste
flow is discharged to St. Vrain Creek.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composites of the combined influent and effluent and
two 24-hour composites of the artesian-well discharge were collected
using SERCO automatic samplers. Influent and effluent samples were com-
posited on a flow weighted basis from readings obtained at the headworks.
The artesian well flow was gaged; and composites were made of equal por-
tions of the hourly samples. Temperature, pll, and conductivity were
measured periodically at the three sampling stations. Grab samples of
the combined effluent were collected for bacteriological analysis. Chlorine
residual measurements were not made as the chlorinatlon facilities were
not in operation during the survey.
During the survey, the following observations were made:
1. Raw sludge was centrifuged and hauled, in an open dump truck,
to the city dump. On two occasions, sludge was observed being spilled,
on turns or sudden stops, The sludge was not being buried at the dump;
rather, the material was dumped in such a manner that there was a potential
for pollution of St. Vrain Creek. Fred Matter, Assistant Director of the
Water Pollution Control Division, Colorado State Department of Health, was
notified of this procedure.
2, Effluent from the primary clarifier in the trickling filter plant
flowed through a rectangular open channel located so that during peak
flow excess wastewater spilled over one side of the channel and mixed
with the artesian well water. This condition was observed each time the
-------
90
influent flow rate exceeded 5.5 mgd (approximate pumping capacity).
3. The ABF plant was being operated as a high-rate trickling filter
at the time of the survey. This mode of operation was necessary because
of inadequate sludge recycle pumping capacity.
4. Laboratory facilities were provided for the performance of
chemical tests of sewage quality. Tests performed include BOD, suspended
solids, settleable solids, chlorine residual, pE, volatile acid, and
alkalinity. These tests are run daily, five days per week.
5. Adequate routine maintenance was being provided.
The survey data [Table 1] indicate that the overall BOD removal
A
efficiency ranged from 45 to 86 percent and averaged 63 percent. This
was in violation of State requirements (i.e., a minimum of 80 percent BOD
removal). The average BOD was 57 mg/1 after dilution by well water
(1,770 Ib BOD/day are discharged to St. Vrain Creek). At the point of
discharge the effluent was essentially the entire flow of the creek
(RM 22.3 to RM 22.0) as the flow in St. Vrain Creek was diverted just
upstream by the Great Western Sugar Company.
Chlorination facilities were not in operation during the survey
because of equipment malfunction (i.e., chlorinator froze). Densities
of fecal coliform bacteria ranged from 470S000 to 1,200,000/100 ml
[Table 2].
A stream survey, conducted in September 1971, revealed that the
discharge from the Longmont plant caused water quality degradation in
* The overall BOD efficiency was calculated by subtracting the load
contributed by the artesian well water.
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
LONGMONT WASTEWATER TREATMENT FACILITY
JANUARY 31-FEBRUARY 2, 1972
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent Combined Effluent^/
Range
2.75-3.17
7.0-7.8
8.0-11.0
825-1,400
172-218
324-834
811-1,080
154-372
Average Range Average
2.95 3.40-4.10 3.72
7.1-7.3
4.5-10.0
1,000-2,000
188 20-78 57
576 143-371 261
925 781-1,540 1,050
229 36-104 65
Artesian Well Water
Range
0.60-0.94
7.0-7.3
4.0-8.5
1,150-1,800
2.4-5.6
35-44
1,190-1,360
1-9
Average
0.783
3.5
39
1,280
6
Percent?/
Removal
42-48
0-31
13-83
a/ Analyses of BOD, COD, total solids, and suspended solids were performed on composite samples.
b/ Combined effluent includes the effluents from the trickling filter and ABF plant and the artesian well water.
~c/ Removal efficiencies were calculated by subtracting the load contributed by the artesian well water from the
combined effluent.
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92
TABLE 2
BACTERIOLOGICAL RESULTS
LONGMONT WASTEWATER TREATMENT FACILITY
Total Fecal
Coliform Colifona
Date Time Count/100 ml Count/100 ml
January 31, 1972 1015 7,900,000 1,100,000
1330 8,000,000 1,200,000
February 1, 1972 1000 11,000,000 830,000
1300 10,000,000 870,000
February 2, 1972 0920 8,300,000 470,000
1115 6,600,000 780,000
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93
St. Vrain Creek (e.g. increased fecal caliform bacteria levels; bottom
deposits). A subsequent stream survey, in December 1971, showed that
the discharges from the Longmont plant and from the Great Western Sugar
Company mill were detrimental to the receiving water. Dissolved oxygen
values were less than 4 mg/1 at all times and fell below 3 mg/1 50 percent
of the time. Fecal coliform bacteria densities increased; Sphaerotilus}
a filamentous bacterium, covered the stream bottom; and organic solids
formed large sludge beds in the creek. The intensity of the pollution
was sufficient to eliminate virtually all intolerant benthos (mayflies
and caddisflies) and to greatly reduce the numbers of tolerant sludge-
worms and bloodworms.
In order to eliminate the above conditions, the Longmont municipal
treatment plant discharge must contain no more than 25 mg/1 each of bio-
chemical oxygen demand and suspended solids. Requirements for the Great
Western mill are discussed in the report, "Technical Appendix on Indus-
2/
trial Waste-Source Evaluations."—
D. SUMMARY AND CONCLUSIONS
1. The Longmont wastewater treatment facilities were not providing
adequate treatment. Average efficiency of BOD removal was less than
the 80 percent level required by the State.
2. Disinfection of the effluent was not being provided owing to
equipment malfunction.
3. The ABF plant was operating as a high-rate trickling filter
because of operational problems with the filter.
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94
4. The effluent from the facility was essentially the entire flow
in St. Vrain Creek because of an upstream diversion.
5. The design capacity of the facility is limited by pumping ca-
pacity. At peak flows, primary clarifier effluent overflows into the
outfall line.
E. RECOMMENDATIONS
It is recommended that:
1. The biochemical oxygen demand and suspended solids in the ef-
fluent not exceed 20 mg/1 or 850 Ib/day of each, whichever is less.
2. Disinfection of the effluent be provided at all times.
3. Pumping capacity of the plant be increased to prevent primary
treated sewage from overflowing the channel into the outfall line to
St. Vrain Creek.
F. REFERENCES
_!/ Status of Municipal Waste Treatment in the South Platte River
Basin., Colorado, 1964-67, U. S. Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967.
2J Technical Appendix on Industrial Waste-Souroe Evaluations,
Water Quality Investigations in the South Platte River Basin,
Colorado, 1971-72, Environmental Protection Agency, National
Field Investigations Center-Denver and Region VIII, Denver,
Colorado, June. 1972.
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95
LOVELAND WASTEWATER TREATMENT PLANT
LOVELAND, COLORADO
A. INTRODUCTION
The Loveland wastewater treatment facility, located on the Big
Thompson River (RM 260.4/24.5), serves an estimated 17,000 persons,
plus Hewlett-Packard electronic plant with an undetermined amount of
industrial wastes. The plant is manned eight hours/day, five days/
week by two operators and, during the summertime, by one parttime
helper. The capitol cost of the plant in 1962 was $600,000; in 1971
the operation budget was $685700.
This plant was evaluated in March 1966 and January 1967 as part
of the South Platte River Basin Project studies.— At that time, the
average daily flow was 1.8 mgd or approximately 130 gallons per capita.
Adequate disinfection was not provided. The BOD and suspended solids
removal efficiencies ranged from 76 to 83 percent and 73 to 87 percent,
respectively.
Personnel of the National Field Investigations Center-Denver con-
ducted an in-plant survey from January 31 to February 3, 1972, in order
to determine the effectiveness of waste treatment practices and the
waste loads discharged to the Big Thompson River. Mr. Dallemand,
Director of Public Works, was contacted for assistance and information.
B. WASTE TREATMENT FACILITIES
This plant is designed for an average flow of 3.0 mgd with a capacity
for 6.0 mgd at peak flow. Minimum flows are about 1.8 mgd. The principal
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96
components of the plant [Figure 1] are:
1. Preliminary treatment — bar screen, grit chamber, and comminutor;
2. Primary treatment — two clarifiers (78 ft. in diameter and
7.75 ft side water depth (SWD); two-hour detention time at an
2
overflow rate of 800 gal/ft /day;
3. Secondary treatment -- two high-rate trickling filters (each
98 ft in diameter, 6 ft 3 in depth) designed for a BOD loading
of 75 lb/1,000 ft3 and a hydraulic loading of 22 million
gal/acre/day; one clarifier (rectangular with dimensions 41 ft
by 92 ft by 9 ft SWD), detention time of two hours at an over-
flow rate of 800 gal/ft2/day;
4. Disinfection •— chlorine added to secondary clarifier; and
5. Digestion ~ two-stage anaerobic digester (primary digester
3
35 ft in diameter, 20 ft SWD, unit loading 0.2 Ib/ft , gas
recirculation); secondary digester same size as primary (no
gas recirculation). Digested sludge is removed to drying beds
designed for 1.25 ft2/capita (14 beds each 20 ft by 75 ft).
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Influent and effluent sampling (three 24-hr composites) was conducted
using SERCO automatic samplers during the period January 31 through
February 2, 1972. Samples were composited on a flow weighted basis from
readings taken at the headworks. Periodic measurements were made of
temperature, pH, and conductivity„ Grab samples of the effluent were
also collected periodically for bacteriological analyses and for chlorine
residual measurements.
-------
INFLUENT
TfiilTMEMT
1
/ FRIHARY \
I CLARIFIER 7"
V^y
UiiSE Tl TWI-STASE
ANAERiSIC IICESTEIS
THEN Tl IRYIN£
BEIS (U)
LOCATION MAP
LOVELAND
PLANT
/ SEC8ND»IY\
CLARIFIER
WITH
IHLOR1NATIOIL
EFFLUENT
IIS THSiPSBN RIVER
KEY
WATER
NOT TO SCALE
Figure 1. Wastewater Treatmeat Plant . L«veia««i
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97
A review of the survey data [Table 1] shows that the BOD removal
efficiency ranged from 59 to 71 percent which is in violation of State
requirements. However, the plant was not hydraulically or organically
overloaded.
Chlorine residual values [Table 2] ranged from 0.3 to 0.8 mg/1 less
than the minimum required by the State of Colorado (i.e., 1 mg/1 after
15 minutes detention). The fecal coliform bacteria densities ranged from
<100 to 22,000/100 ml.
21
Stream surveys in September and December 1971— revealed that the
discharge from the Loveland wastewater treatment plant degraded the water
quality and the stream bed environment of the Big Thompson River.
Inorder to maintain water quality in the Big Thompson River during
low flow conditions (assumed to be 25 cfs) , the effluent must contain
no more than 25 mg/1 each of BOD and suspended solids.
Laboratory facilities have been provided at the Loveland wastewater
treatment plant for the performance of chemical tests of sewage quality.
Chlorine residual;, BOD, pH, suspended solids, volatile acids and alkalinity
are analyzed weekly. Records are maintained on all analysis that are
performed.
D. SUMMARY AND CONCLUSIONS
1. The BOD removal efficiency did not meet the Colorado require-
ments for secondary treatment because of plant operational problems.
2. Adequate disinfection of the effluent was not being provided.
3. The discharge from this plant results in water quality degrada-
tion of the Big Thompson River.
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
LOVELAND WASTEWATER TREATMENT FACILITY
JANUARY 31-FEBRUARY 3, 1972
Parameter-
Flow (mgd )
pH (S.U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
6.8-9.75
8-11.5
800-1,100
148-210 174
512-921 680
839-1,050 933
232-318 260
Effluent
Range Average
2.62-2.83 2.73
6.9-8.1
6.0-10.0
950-1,100
60-66 62
245-301 264
671-692 679
46-64 53
Percent
Removal
59-71
50-73
20-36
79-80
a./ Analyses of BOD, COD, total solids, and suspended solids are performed on composite samples.
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99
TABLE 2
BACTERIOLOGICAL RESULTS
LOVELAND WASTEWATER TREATMENT FACILITY
Date
January 31, 1972
February 1, 1972
February 2, 1972
Time
0810
1415
1220
1450
1225
1505
Total
Colif orm
Count./ 100 ml
<100
2,300,000
>80,000
>80,000
150,000
630,000
Fecal
Colif orm
Count/100 ml
<100
22,000
21,000
20,000
400
6,600
Chlorine
Residual
mg/1
0.8
0.8
0.4
0.6
0.3
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100
E. RECOMMENDATIONS
It Is recommended that:
1. The biochemical oxygen demand and suspended solids in the plant
effluent each not exceed 25 mg/1 or 650 Ib/day (based on present design),
whichever is less, inorder to prevent degradation in water quality of the
Big Thompson River.
2. Disinfection of the plant effluent be accomplished in accordance
with the Colorado requirements.
F. REFERENCES
I/ Municipal Waste Report, Metropolitan Denver Area, South Platte
River Basin, PR-3, U. S. Department of Health, Education, and
Welfare, Public Health Service, Division of Water Supply and
Pollution Control, South Platte River Basin Project, Denver,
Colorado, December 1965. Appendix B.
2/ Water Quality Investigations in the South Platte River Basin,
Colorado, 1971-72, National Field Investigations Center-Denver
and Region VIII, Denver, Colorado,, April 1972.
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101
LYONS WASTEWATER TREATMENT PLANT
LYONS, COLORADO
A. INTRODUCTION
The Lyons treatment plant serves a population of approximately
1,000 people and is staffed by one part-time operator. Constructed
in 1957, the original plant consisted of a clarigester. An aerated
lagoon was added in 1969.
I/
An in-plant evaluation in 1964— showed that 65,000 gpd received
inadequate treatment in this primary plant. Additional treatment facil-
ities, including disinfection and improved operation, were recommended.
An in-plant survey was conducted during the period September 27-29,
1971. William Bracketts Plant Operator, provided information and
assistance,
B- WASTE TREATMENT FACILITIES
The principal components of the system [Figure 1] are:
1. Pri^rT'/ treatment — clarigester (24 ft in diameter and 18 ft
deep)r
2o Secondary treatment — aerated lagoon (surface area of approxi-
mately one acre) employing one 3-hp mechanical aerator;
3. Disinfection — chlorine contact chamber (7 ft in diameter
and 11 ft deep) with a detention time of 90 minutes, at
present flow of 0.05 mgd. (There was not any information
available regarding design capacity.); and
4, Sludge disposal — from clarigester to aerated lagoon.
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102
C. DISCUSSION OF PLANT EVALUATION AMD FINDINGS
Grab samples of the effluent (before and after chlorination) were
collected daily on September 28 and September 29, 1971. Bacteria
counts and chlorine residuals were determined on the samples collected
after chlorination. Temperature, pH, and conductivity were measured each
time a sample was collected.
The chlorination facilities were inoperative on September 27 and 28,
1971, due to failure of an electrical pump. The pump was replaced, and
chlorination initiated September 29. Disinfection was adequate on this
date [Table 1].
The survey data [Table 2] show that the effluent - from the Lyons
wastewater treatment facility contained 20 mg/1 of BOD, a loading of eight
pounds per day to the St. Vrain Creek. The ten-year, seven-day low flow
for St. Vrain Creek is 0.8 cfs. At this plant contribution, the BOD of
the stream would increase about 2 mg/1 at low flow.
D. SUMMARY AND CONCLUSIONS
1. Loadings of BOD and suspended solids from the Lyons plant are
minimal and will not cause any adverse effect upon St. Vrain Creek.
2. Chlorination facilities were out of service because of pump
failure two of the three days of the survey.
E. RECOMMENDATIONS
It is recommended that the necessary auxilary equipment be Installed
to preclude shutdown of the chlorination facilities.
-------
IHFIUEIT
KEY
EFFLIENT
ST.tl»H CIEEK
LOCATION MAP
YONS
ST VRAIN
CREEK
HWY 7
NOT TO SCALE
WATER
Figure 1. Wastewaler TrealBeit Plait . Ly»as
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103
TABLE 1
BACTERIOLOGICAL RESULTS
LYONS WASTEWATER TREATMENT FACILITY
Date
September 27, 1971
September 28, 1971
September 29, 1971-'
Time
1230
0915
1500
0900
1305
Total
Coliform
Count/100 ml
490,000
500,000
>80,000
>8,000
>8,000
Fecal
Coliform
Count/100 ml
13,000
55,000
18,000
870
730
C12
Residual
mg/1
0.0
0.0
0.0
1.7
1.3
a/ The effluent was being chlorinated on this date.
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104
TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
LYONS WASTEWATER TEEATMENT FACILITY
SEPTEMBER 27-29, 1971
Parameter
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
TOG (mg/1)
Total N (mg/1)
N02 + N03 (mg/1)
Total P (mg/1)
Effluent
Range
0.05^
6.8-7.6
14-16
200-250
200-1,850
50-80
30-40
7.8-8.0
0.17-0.16
3.4-3.6
Average
7.2
15
225
20a/
1,030
65
35
7.9
if
0.16
3.5
a/ All values are the same.
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105
F. REFERENCE
\J Status of Municipal Waste Treatment in the South Platte River Basin,
Colorado, 1964-67, U. S. Department of the Interior, Federal Water
Pollution Control Administration, South Platte River Basin Project,
December 1967.
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106
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107
SOUTH ADAMS WATER AND SANITATION DISTRICT
WASTEWATER TREATMENT PLANT
9699 McKAY AVENUE
DERBY, COLORADO
A. INTRODUCTION
The South Adams Water and Sanitation District plant, located on the
South Platte River (RM 306.7), serves approximately 19,500 people. The
plant, staffed with a chief operator (Class A) and two plant operators
(Class B), is manned 14 hours/day, seven days/week. Original construc-
tion of the plant was carried out in 1957; there have been no major re-
visions since then.
This plant was evaluated during the South Platte River Basin Project
studies.— At that time it served 16,000 people and was providing ade-
quate treatment (91 percent BOD removal)- Laboratory tests included pH
and residual chlorine on a daily basis; and on a weekly one, suspended
solids and volatile acids. Records of flow, gas production, and digested
sludge were prepared daily by the chief operator. Additional tests such
as the BOD of influent and effluent were recommended.
Between January 31 and February 4, 1972, an in-plant survey was con-
ducted by personnel of the National Field Investigations Center-Denver
to ascertain waste treatment practices and waste loads discharged.
Ray Duggans, Chief Operator, provided assistance and information.
B. WASTE TREATMENT FACILITIES
The plant is designed for a capacity of 2.5 mgd. Principal com-
ponents [Figure 1] of the system are as follows:
-------
108
1. Preliminary treatment — grit chamber, bar screen, and comminutor;
2. Primary treatment — clarifier (100 ft in diameter and 7 ft side
water depth (SWD));
3. Secondary treatment — one high-rate trickling filter (140 ft
in diameter, 6 ft rock depth), one clarifier (100 ft in diameter,
7 ft SWD);
4. Disinfection — chlorine contact chamber (baffled) , detention
time of 15 minutes at 2.5 mgd; and
5. Digestion — two-stage (primary digester, 45 ft in diameter by
37.5 ft, secondary digester, same size as primary unit), digested
sludge is placed in drying beds (five at 175 ft by 45 ft each).
Plant operators provide adequate routine maintenance. Laboratory
facilities have been provided for the performance of chemical tests of
sewage quality. The tests performed are limited to basic analyses (e.g.,,
pH, chlorine residual, suspended solids, volatile acid). Records of plant
operation reflect flow, gas production and digested sludge quality.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
A three-day sampling program commenced on January 31, 1972. Samples
(three 24-hr composites) were collected of the influent and the effluent
(before chlorination) using SERCO automatic samplers, which collect a
sample portion each hour. These samples were then composited on a flow
weighted basis from readings at the headworks,, The samples were analyzed
for BOD, COD, and solids [Table 1]. Temperature, pH, and conductivity
were measured at all sampling locations. Periodic grab samples were
-------
IMFLHENT
FiELiiiNAiY TtEATMEKT
Tt PRIMART
CLARIFIER
CHLSRINE
C8BTACT
CHANBER
SLHIE Tl T«I-STA«E
AHAERIIIC IICfSTEIS
All TNEN Tl IRTIilt IEIS
UBDSJJO
PRIMARY
CLARIFIER
KEY
*-SLUD6E
EFFL9EMT
SO. PLATTE RIVER
Figure
1. Waslewater Treatment Plant . South Adams Saiiltti«B District
-------
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
SOUTH ADAMS WASTEWATER TREATMENT FACILITY
JANUARY 31-FEBRUARY 3, 1972
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
7.0-7.7
8-12
1,300-3,200
200-241 223
450-789 579
1,190-1,620 1,380
89-400 236
Effluent
Range
1.8-1.9
7.3-7.7
6-13
1,500-2,000
50-70
205-274
1,110-1,190
48-298
Percent
Average Removal
1.8
62 71-75
239 47-65
1,160 0-27
145 0-78
a) Analyses of BOD, COD, total solids, and suspended solids were performed on composite samples,
-------
10
collected for bacteriological analyses and measurements of chlorine re-
sidual [Table 2].
The BOD and suspended solids waste loads entering the plant at the
time of this survey were slightly less than those observed during the
1964 survey. The BOD removal efficiency ranged from 71-75 percent, sig-
nificantly less than that observed in 1964. Solids removal was also poor.
High solids carry-over was noted from the final clarifier during the survey
Disinfection was very effective as evidenced by the low bacterial
densities [Table 2]; however, the high chlorine residuals observed indi-
cate an excessive amount of chlorine was used. Residuals as high as 4.0
mg/1 were measured.
D. SUMMARY AND CONCLUSIONS
Although the South Adams plant was not hydraulically or organically
overloaded, it did not provide adequate BOD and suspended solids removal.
The low removal efficiencies were attributed to the high carry-over of
suspended solids in the effluent.
Disinfection was very effective but an excessive amount of chlorine
was applied during the survey. Detrimental effects can occur in the
receiving stream at the high residuals observed.
E. RECOMMENDATIONS
It is recommended that:
1. The effluent from this plant contain not greater than 30 mg/1
each of biochemical oxygen demand and suspended solids or the total load
discharged daily not exceed 650 pounds of each at present design flow.
-------
Ill
TABLE 2
BACTERIOLOGICAL RESULTS
SOUTH ADAMS WASTEWATER TREATMENT FACILITY
Date
January 31, 1972
February 1, 1972
February 2, 1972
Time
0735
0900
1420
0920
1345
0800
0900
Total
Coliform
Count/100 ml
20
4,000
<4
<4
30
100
Fecal
Coliform
Count/100 ml
30
4
<4
8
Chlorine
Residual
mg/1
1.5
0.5
4.0
2.0
3.0
1.2
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112
2. The chlorine application rate be controlled to produce a residual
of 1,0 mg/1 after 15 minutes detention at peak hourly flow and at no time
shall the fecal coliform bacterial density exceed 1,000/100 ml,
F. REFERENCE
I/ Municipal Waste Report, Metropolitan Denver Area., South Platte River
Basins U, S. Department of Health, Education, and Welfare, Public
Health Service, Division of Water Supply and Pollution Control,
South Platte River Basin Project, Denver, Colorado, December 1965,
Appendix B.
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113
SOUTH LAKEWOOD SANITATION DISTRICT
WASTEWATER TREATMENT PLANT
700 DEPEW
LAKEWOOD, COLORADO
A. INTRODUCTION
The South Lakewood Sanitation District Wastewater Treatment Plant
serves a population of approximately 15,000. The contact stabilization
process is used, with the effluent being discharged to the South Platte
River (RM 318.9).
The plant is staffed by the district superintendent and one opera-
tor and is manned eight hours/day, seven days/week. The annual operating
budget is $48,000.
A survey in 1964— indicated that the plant served 6,500 persons
and was staffed with one operator. The investigation concluded that the
plant was not providing adequate treatment and that laboratory control
was not maintained to provide efficient daily operation of the facility.
A 1971 in-plant survey was conducted from August 17 through 20.
John Kruz, district superintendent, provided assistance and information.
B. WASTEWATER TREATMENT FACILITIES
The plant [Figure 1] is designed for a capacity of 1.2 mgd and an
organic loading of 4,880 pounds BOD per day. Principal components of
the system are:
1. Preliminary treatment — bar screen and grit chamber;
2. Secondary treatment — contact stabilization system (one
contact tank and two stabilization or reaeration tanks) , five
-------
14
clarifiers (four rectangular, approximately 60 ft x 20 ft x 9 ft
and one circular, 50 ft in diameter) and a polishing pond;
3. Disinfection — chlorine added to polishing pond influent and
effluent with the two-mile-long outflow line to the South Platte
River providing contact time, and
4. Sludge handling — aerobic digestion, with sludge disposal to land.
An EPA grant offer has been made and a contract awarded for expansion
of the plant from a design capacity of 1.2 to 1.8 mgd. This expansion in-
cludes a sixth clarifier, a new grit chamber, and sludge handling equipment.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hour composites of the influent and effluent (after chlor-
ination) were collected using SERCO automatic samplers. The effluent
samples were collected at a manhole located approximately 50 yd from the
South Platte River. Samples were composited on a flow weighted basis
from measurements taken at the headworks. Periodic measurements were
made for pH, temperature, and conductivity. Grab samples were also col-
lected of the effluent (after chlorination) for bacteriological analyses
and for chlorine residual measurements.
A review of the survey data [Table 1] revealed that the South Lakewood
plant was discharging to the South Platte River, a waste load of 483 pounds
of BOD and 890 pounds of suspended solids. The BOD removal efficiency
was less than the 80 percent minimum required by the State. The flow
averaged 1.8 mgd. The expanded treatment facilities are designed for this
flow which does not allow for any future increase in flow.
-------
IKFLBEMT
CONTACT
STAIILIZATIIM
TASK
CTIVATEI
CHLORIME.
CHLORINE _
KEY
-WATER
SLUDGE
EFFLUENT TO
SOUTH PLATTE 8
ItSESTEi
LOCATION MAP
OUTF
ALL LINE
IILES
SO. LAKE WOOD
PLANT
NOT TO SCALE
Figure
Waslewater Treatment Plant , South Lakewood Sani
' Ls I r
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TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
SOUTH LAKEWOOD WASTEWATER TREATMENT FACILITY
AUGUST 17-20, 1971
Parameter^
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
TOG (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
6.4-8.4
18-22
850-950
100-110 103
81-161 122
640-820 717
90-150 113
Effluent
Range
1.7-1.8
6.7-8.6
17-22
900-1,000
13-60
21-34
540-660
40-90
Average
1.8
33
26
600
60
Percent
Removal
45-87
74-81
5-27
0-67
a/ Analyses of BOD, TOG, total solids, and suspended solids were performed on composite samples,
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116
Chlorine residuals in the effluent varied from 0.05 to greater than
1.0 mg/1 [Table 2], Disinfection was generally adequate as evidenced by
the fecal coliform bacteria densities. It would appear, however, that
most of the time, an excessive amount of chlorine was being applied.
D. SUMMARY AND CONCLUSIONS
The South Lakewood plant did not provide adequate treatment of
wastewater, (i.e., less than 80 percent BOD removal) as required by the
State of Colorado. The plant is presently under expansion to a design
capacity of 1.8 mgd; this flow value was observed at the time of the
survey.
E. RECOMMENDATIONS
It is recommended that:
1. The operation of this plant be discontinued and all wastewater
be diverted to the Metropolitan Denver Sewage Disposal system.
2. In the interim, treatment practices provide an effluent that
contains no more than 30 mg/1 each of biochemical oxygen demand and
suspended solids, or 450 Ib/day, whichever is less.
F. REFERENCE
I/ Municipal Waste Report., Metropolitan Denver Area, South Platte
River Basin, PR-3, U. S. Department of Health, Education, and
Welfare, Public Health Service, Division of Water Supply and
Pollution Control, South Platte River Basin Project, Denver,
Colorado, December 1965. Appendix B.
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117
TABLE 2
BACTERIOLOGICAL RESULTS
SOUTH LAKEWOOD WASTEWATER TREATMENT FACILITY
Date
August 17, 1971
August 18, 1971
August 19, 1971
Time
0920
1220
1410
1400
1940
0810
1105
1545
Total
Coliform
Count/ 100 ml
1,200
56
340,000
>80,000
180
30
1,600
7,900
Fecal
Coliform
Count/100 ml
<4
<4
48,000
>6,000
29
<4
440
700
Chlorine
Residual
mg/1
>1.0
>1.0
<1.0
0.05
>1.0
1.0
0.60
>1.0
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119
STIRLING WASTEWATER TREATMENT PLANT
STERLING, COLORADO
A. INTRODUCTION
The Sterling wastewater treatment facility is located on the South
Platte River (KM 148.6). This high-rate trickling filter plant, con-
structed in 1961 and expanded in 1966, presently serves a population of
approximately 11,000 people. The plant is manned eight hours/day six
days/week by three operators and a superintendent. Wastewater (0.49 mgd)
from the Sterling Beef racking Company is also treated by this muni-
cipal plant.
A survey, conducted in 1966,— showed that a) more than 80 percent of
the BOD loading was from the Sterling Beef Packing Company; b) the plant
was organically overloaded; c) the BOD removal efficiency was less than
80 percent; and d) disinfection of the effluent was not being provided.
As a result, pre-treatment of packing house wastes was recommended.
A recent lo-plai.t survey has been conducted (January 26 through 29,
1972). At th.'..s Lime Richard Getz, plant superintendent, provided infor-
mation and assistance.
B. WASTE TREATMENT FACILITIES
The plant is designed for a flow of 2.4 mgd and an influent BOD
loading of approximately 6,000 Ib/day. The principal components [Figure 1]
of this system are:
1. Preliminary treatment -- bar screen, grit chamber, and comminutor;
2. Primary treatment — two clarifiers (each 60 ft in diameter and
7 ft deep);
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120
3. Secondary treatment -- two trickling filters, with diameters of
105 ft and 75 ft, respectively (both are 7 ft deep), and two
clarifiers (one 55 ft in diameter and 7 ft deep and one 50 ft
in diameter and 13.5 ft deep);
4. Disinfection — chlorine contact chamber (36 ft by 12 ft by
4 ft); and
5. Digestion — two-stage anaerobic digestion system (each digester
is 45 ft in diameter and 28 ft deep) , with digested sludge re-
moved to drying beds.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
Three 24-hr composite samples of the influent and effluent (before
chlorination) were collected using SERCO automatic samplers and composited
on a flow weighted basis from readings obtained at the headworks. A grab
sample of the wastewater discharge from the Sterling Beef Packing Company
was collected daily in order to provide an estimate of the total load from
that waste source. Temperature, pH, and conductivity were measured
periodically at all three sampling positions. Grab samples of the muni-
cipal plant effluent (after chlorination) were collected periodically for
bacteriological analyses and measured for chlorine residual.
The Sterling Beef Company provides primary treatment of wastewater
(a clarifier — 45 ft in diameter by 9 ft deep) prior to discharge into the
Sterling wastewater treatment plant. Grease and solids removed by the
clarifier are processed by the Company. Grab samples of the packing
house effluent showed that the BOD ranged from 910-1800 mg/1 [Table 1].
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HAIR IHFLUEHT
STERLING COLO BEEF
PACKING CO. EFFLUENT
x ^ ,'
\ /
91SESTEI jHI DIGESTER
SLUDfiE
NOT TO SCALE
EFFiyENT
SOUTH PLATTE RIVER
Figure 1. Wastewaler Treatraesi!
si , SlerSing
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121
TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
STERLING PACKING PLANT, STERLING, COLORADO
JANUARY 26-28, 1972
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (ymhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Effluent
Range
0.27-0.76
7.0-8.0
29.5-40
1,700-2,200
910-1,800
2,630-2,860
2,840-4,040
250-1,610
Average
0.49
1,270
2,750
3,550
870
a/ Only grab samples were collected once daily.
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122
The high Influent BOD [800-970 mg/1 as shown in Table 2] at the Sterling
municipal treatment plant indicates that the packing plant contributed
the major portion of the organic load.
The organic load (19,00) Ibs/day BOD) at the municipal facility was
three times the design capacity. Removal efficiencies ranged from 40-82
and 57-95 percent for BOD and suspended solids, respectively. The levels
of BOD and suspended solids in the effluent were excessive.
To achieve satisfactory treatment at the municipal plant (i.e. 30 mg/1
BOD and suspended solids) the packing plant will need to pretreat its wastes
to levels comparable to domestic sewage (250 mg/1).
Disinfection of the effluent was inadequate. Fecal—coliform bac-
teria densities ranged from 63,000 to 3,000,000/100 ml [Table 3]. The
chlorine dosage rate of 50 Ib/day (3 mg/1) was not adequate and far below
the level recommended by Colorado for adequate disinfection, i.e. 15 mg/1
21
for trickling filter effluents.— At average flow, the detention time
in the contact basin was only nine minutes. The State requires a chlorine
residual of 1 mg/1 after 15 minutes contact time at peak hourly flows.
Laboratory facilities have been provided for the performance of
chemical tests of sewage quality. Tests (BOD and settleable solids) are
performed daily on the plant influent and effluent and on the Sterling
Beef Packing Company effluent. The chlorine residual in the plant
effluent is also determined. Additional laboratory analyses should be
made to insure efficient operation of the plant.
Routine maintenance at this plant is inadequate (e.g. weirs on
clarifiers should be cleaned weekly; bar screens should be kept clean).
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TABLE 2
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
STERLING WASTEWATER TREATMENT FACILITY
JANUARY 25-29, 1972
a/
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity (pmhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Influent
Range Average
7.4-7.8
10-20
1,950-2,200
800-970 903
1,360-3,070 1,980
4,110-6,460 5,650
1,200-3,400 2,230
Effluent
Range
2.29-2.74
7.3-7.7
9.0-16,5
2,000-3,500
175-480
458-788
2,520-3,270
112-512
Average
2,53
288
577
2,830
269
Percent
Removal
40-82
42-84
34-61
57-95
a./ Analyses of BOD, COD, total solids, and suspended solids were performed on composite samples.
ho
to
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124
TABLE 3
BACTERIOLOGICAL RESULTS
STERLING WASTEWATER TREATMENT FACILITY
Date
January 26, 1972
January 27, 1972
January 28, 1972
Time
0750
0855
0800
0900
0720
0925
Total
Coliform
Count/100 ml
1,500,000
2,700,000
1,600,000
820,000
870,000
710,000
Fecal
Coliform
Count/ 100 ml
95,000
280,000
67,000
72,000
3,000,000
63,000
Chlorine
Residual
mg/1
0.0
0.0
0.0
0.0
0.1
0.0
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125
D. SUMMARY AND CONCLUSIONS
1. Sterling wastewater treatment plant did not provide adequate BOD
removal because of the gross organic overload.
2. The Sterling Beef Packing Company contributes the major portion
of the waste load to the Sterling plant.
3. Disinfection of the effluent was inadequate; the chlorine dosage
rate and contact time were less than those recommended by the State of
Colorado.
4. Laboratory analyses performed are not adequate (i.e. digestor
operation).
E. RECOMMENDATIONS
It is recommended that:
1. The chlorine dosage rate be increased to insure adequate dis-
infection of the effluent (i.e. 1 mg/1 after 15 minutes detention); and
the contact chamber be enlarged to provide a minimum of 15 minutes deten-
tion at peak hourly flow.
2. The Sterling Beef Packing Company provide pretreatment of wastes
to such a degree that the wastewater discharged to the Sterling municipal
treatment plant does not exceed the strength of normal domestic sewage
(250 mg/1 each of biochemical oxygen demand and suspended solids).
3. The Sterling wastewater treatment plant be expanded so as to
produce an effluent that contains no more than 30 mg/1 or 600 Ib/day
each of biochemcial oxygen demand and suspended solids at design flow,
whichever is less.
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126
4. Plant operators be provided training in the operation of the
plant by attendance at an operator school and be provided on-the-job
training.
F. REFERENCES
17 Status of Municipal Waste Treatment in the South Platte River
Basin, Colorado, 1964-67, U. S. Department of the Interior,
Federal Water Pollution Control Administration, South Platte
River Basin Project, December 1967.
2J Criteria Used in the Review of Waste Water Treatment Facilities,
Colorado Department of Health, Denver, Colorado, September 1969.
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127
WHEATRIDGE SANITATION DISTRICT
WASTEWATER TREATMENT PLANT
WHEAT RIDGE, COLORADO
A. INTRODUCTION
The Wheatridge Sanitation District treatment facility is located
on Clear Creek (RM 311.1/7.7). The facility serves approximately 28,000
people and is staffed by a district superintendent, a plant foreman,
three operators, and a secretary. The plant, constructed in 1949, is
manned eight hours/day, five days/week, with periodic maintenance checks
conducted twice daily on weekends. In 1958, additional trickling filters
and secondary clarifiers were built. Total capital cost was $571,000.
Annual operating costs during 1970 were approximately $107,000.
An evaluation of this plant was made during the South Platte River
Basin studies.— The plant did not provide adequate waste treatment at
that time, disinfection was inadequate, and the plant was understaffed.
From February 2 through 5, 1972, an in-plant survey was conducted
to ascertain the waste loads discharged and the efficiency of the plant.
E. H. Snodgrass , District Superintendent, provided information and
assistance during this study.
B. WASTE TREATMENT FACILITIES
The plant has a hydraulic design capacity of 1.8 mgd. Since the
time of the South Platte River Basin Project studies the district has
connected to the Metropolitan Denver Sewage Disposal District (Metro)
plant; as a result, flow in excess of the design flow-capacity can be
diverted to Metro.
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128
Present treatment facilities [Figure 1] consist of the following:
1. Preliminary treatment — two bar screens (not used), two grit
chambers, and two comminutors, operating in parallel;
2. Primary treatment — three clarifiers (each 42 ft in diameter and
4 ft side wall depth (SWD));
3. Secondary treatment — three standard-rate trickling filters
(each 100 ft in diameter and 7 1/2 ft in depth), one clarifier
72 ft in diameter, 4 ft SWD;
4. Disinfection — chlorine contact chamber; and
5. Sludge digestion — two primary digestion tanks, one secondary
tank, and sludge drying beds.
C. DISCUSSION OF PLANT EVALUATION AND FINDINGS
In-plant sampling was conducted February 2 through 5, 1972. Three
24-hr composite samples, collected from both the two influent lines and the
effluent, were analyzed for BOD, COD, and solids all before chlorination.
Composites were made up from grab samples collected manually each hour
and proportioned on the basis of flow measurements (Parshall flume) at
the headworks. The pH, temperature, and conductivity were measured at
sampling locations. In addition, samples of the effluent after chlori-
nation were analyzed for chlorine residuals and for bacteria densities.
The influent BOD load averaged 6,000 Ib/day, or about 15 percent
above the influent waste load observed during the 1964 survey (5,300
2/ i
Ib/day).- Using a trickling-filter loading rate of 25 lb/1,000 ft
the plant has reached its organic loading capacity. The plant discharged
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EAST INFLUENT
WEST INFLUENT
IIRECTEI FLIW T8
#1 PLANT
PRELIMINARY TREATMENT
PRELIMINARY TREATMENT
SLV9IE Tl
TWI-STAIE
AlAERSBiC
liiEITER
PRIMARY
CLARIFIER
PRIMARY
\ CLARIFIER
TRICKLING
FILTERS
TRICKLING
FILTERS
TRICKLING
FfLTEIS
RECIRCIHATliN TO PRIMARY CLARIFIE8S
LOCATION MAP
SLUDGE TO EAST INFLUENT
SECONDARY
CLARIFIER
CHLORINE
CONTACT
CHAMBER
RM3O5.5
7.5
WHEATRIDGE
PLANT
-^SLUDGE
EFFLUENT T8
CLE*RCIEEK NOT TO SCALE
''gure 1. Wastewater Treatment Plant, Wheatridge SaiitatioH District
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129
to Clear Creek a daily average BOD load of 2,420 pounds and a suspended
solids load of 1,540 pounds [Table 1], Removal efficiencies for these
two parameters ranged from 41 to 70 and 28 to 76 percent, respectively,
Disinfection was- inadequate, as evidenced by the bacterial counts [Table 2],
Plant officials reported that approximately 50 pounds of chlorine were used
daily. The recommended dosage rate for chlorination of trickling filter
21
plant effluent is 15 mg/1,— which would require, at design flow rates,
addition of about 225 pounds of chlorine daily.
The existing flow meter at the plant did not measure the total flow
but only that portion that moved through the east side of ;;he plant. The
total flow, measured during the 1972 survey, was found to be 2,15 mgd, or
approximately 20 percent in excess of the design capacity. Plant offi-
cials reported that, except for brief periods (about 10 minutes) in the
morning and evening; no flow is diverted to Metro.
Plant operation and maintenance was considered to be poor and is
carried out in a sporadic manner at best. None of the operators hold
higher than a Class D certificate, which is the first step in the
Voluntary Program of the Colorado Committee for Certification of Water
and Sewage Works operators.
Do SUMMARY AND CONCLUSIONS
The Wheatridge Sanitation District plant did not provide adequate
secondary treatment or disinfection. The plant was hydraulically over-
loaded by about 20 percent. The flow in excess of plant capacity (1.8 mgd)
was not diverted to Metro although plant officials are permitted to do
this. The plant has apparently reached its organic loading capacity.
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TABLE 1
SUMMARY OF FIELD MEASUREMENTS AND ANALYTICAL RESULTS
WHEATRIDGE WASTEWATER TREATMENT PLANT
FEBRUARY 2-5, 1972
Parameter-
Flow (mgd)
pH (S.U.)
Temperature (°C)
Conductivity
(pmhos/cm)
BOD (mg/1)
COD (mg/1)
Total Solids
(mg/1)
Suspended Solids
(mg/1)
East Influent
Range Avg
1.76-1.85 1.82
7.4-8.3
9-13
750-1,700
200-540 322
420-845 610
598-1,200 847
114-228 167
West Influent
Range Avg
0.30-0.36 0.33
7.3-8.3
9.5-14.0
750-1 , 100
280-493 368
570-809 665
813-980 872
178-224 199
Total Influent Effluent
Range Avg Range Avg
2.09-2.21 2.15 2.09-2.21 2.15
6,8-7.5
8.0-12.5
800-1,400
118-162 135
245-386 303
601-622 611
2,240-4,190 3,080 54-116 87
Percent
Removal
41-70
42-56
5-48
28-76
aj Analyses on BOD, COD, total solids, and suspended solids were performed on composite samples.
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131
TABLE 2
BACTERIOLOGICAL RESULTS
WHEATRIDGE WASTEWATER TREATMENT FACILITY
Date
February 2, 1972
February 3, 1972
February 4, 1972
Time
1530
0900
1230
1410
0905
1400
Total
Coliform
Count/ 100 ml
16,000
>80,000
59,000
60
2,700,000
800,000
Fecal
Coliform
Count/100 ml
50
>6,000
92
4
88,000
>60,000
Chlorine
Residual
mg/1
0.2
0.2
0.4
0.0
0.0
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132
Plant operation was poor. Additional operator training is required.
The entire flow of this plant could be diverted into the Metro system.
This approach would be more suitable than the continued operation of the
present facilities.
E. RECOMMENDATIONS
It is recommended that:
1. Operation of the Wheatridge Sanitation District treatment plant
be discontinued and all flow be diverted to the Metro system when the
additional capacity is available.
2. In the interim, all flows in excess of 1.8 mgd be diverted to
Metro, and disinfection practices at the Wheatridge plant be improved so
that the density of fecal coliform bacteria in the effluent at no time
exceed 1,000/100 ml.
F. REFERENCES
I/ Municipal Waste Report, Metropolitan Denver Area, South Platte
River Basin, U. S. Department of Health, Education, and Welfare,
Public Health Service, Division of Water Supply and Pollution
Control, South Platte River Basin Project, Denver, Colorado,
December 1965, Appendix B.
2J Criteria Used in the Review of Waste Water Treatment Facilities,
Colorado Department of Health, September 1969.
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