EPA 904/9/75/003
TECHNICAL ASSISTANCE PROJECT
AT THE
DANVILLE/ KENTUCKY
WASTEWATER TREATMENT PLANT
AUGUST 1975
Environmental Protection Agency
Region IV
Surveillance and Analysis Division
Athens, Georgia
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TECHNICAL ASSISTANCE PROJECT
AT THE
DANVILLE, KENTUCKY
WASTEWATER TREATMENT PLANT
AUGUST 1975
Environmental Protection Agency
Region IV
Surveillance and Analysis Division
Athens, Georgia
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TABLE OF CONTENTS
PAGE
INTRODUCTION 1
SUMMARY 1
RECOMMENDATIONS 3
TREATMENT FACILITY
TREATMENT PROCESSES 5
PRESONNEL 9
STUDY RESULTS AND OBSERVATIONS
FLOW 9
WASTE CHARACTERISTICS ADD REMOVAL EFFICIENCIES 11
HEAD WORKS ' 15
PRIMARY CLARIFIER 16
TRICKLING FILTER 16
FINAL CLARIFIER - ... 17
DIGESTER AND DRYING BEDS 18
SAFETY AND MAINTENANCE ¦ 18
LABORATORY 19
PERSONNEL " 20
APPENDICES
A. ' CHEMICAL "LABORATORY DATA 21
¦ B. STUDY METHODS 26
C. OXYGEN UPTAKE PROCEDURE ' 27
LIST. OF FICURES
FIGURE NO. 1 - WASTEWATER TREATMENT PLANT 6
FIGURE NO. 2 - FLOW AND pH 10
FIGURE NO. 3 - TREATMENT EFFICIENCY - NO. 1 UNITS . 13
FIGURE NO. 4 - TREATMENT EFFICIENCY - NO. 2 UNITS 14
LIST OF TABLES
TABLE I - DESIGN CRITERIA 7
TABLE II. - TRICKLING FILTER FLOW H
TABLE III - WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES. ... 12
TABLE IV - INSTANTANEOUS pH VARIATIONS ' 15
TABLE V - GRIT CHANNEL VELOCITIES__.__._... 15
TABLE VI - PRIMARY CLARIFIER REMOVAL EFFICIENCIES . • . . . . . . .16
TABLE VII - TRICKLING FILTER REMOVAL EFFICIENCIES 17
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INTRODUCTION
A technical assistance study of operation and maintenance problems
at the wastewater treatment plant serving DanvilJe, Kentucky was con-
ducted during August 19-22, 1975, by the U.S. Environmental Protection
Agency, Region IV. Operation and maintenance technical assistance
studies are designed to assist local wastewater treatment plant operators
in maximizing treatment efficiencies as well as assist with special
operational problems. Municipal wastewater treatment plants are selected
for technical assistance studies after consultation with state pollution
authorities. Visits are made to each prospective plant prior to the
study to determine if assistance is desired and if study efforts would bo
productive.
The specific study objectives were to:
© Optimize treatment via control testing and recommended
operation and maintenance modifications,
o Determine influent and effluent waste characteristics,
e Assist laboratory personnel with any possible laboratory
procedure problems, and
q Compare design and current loadings.
A follow-up assessment o£ plant operations and maintenance practices
will be made at a later date. This will be accomplished by utilizing
data generated by plant personnel and, if necessary, subsequent visits
to the facility will be made. The follow-up assessment will determine
if recommendations were successful in improving plant operations and if
further assistance is required.
The cooperation of the Kentucky Department for Natural Resources and
Environmental- Protection (KY-DNREP),-Division of—Water' Quality in planning-
the study is gratefully acknowledged. The technical assistance team is
especially appreciative of the cooperation and assistance received from
Danville City officials and plant personnel.
SUMMARY
The general mechanical condition and appearance of the Danville Waste-
water Treatment Plant was poor. Previous studies by the KY-DNREP
(January 1973 and May 1975) indicated that the plant was poorly operated
and maintained.
Specific operation and maintenance problems documented during this
st.udy are enumerated below:
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o The mechanically cleaned bar screen required replacement
of missing side places. In addition, the shoes on the.
mechanical cleaning device had been installed backwards.
o The flow recorder and totalizer were not operating.
e The coiuminutor on one of the two parallel grit channels
would not run for extended periods without shutting off.
This condition not only allowed large solids to enter
subsequent treatment units but unbalanced the flow into
the parallel grit channels.
o Due to clogging of the auxiliary bar screens, at the
entrance of each grit channel wastewater backed into
the throat of the Parshall flume and grit material was
deposited due to the reduced velocity.
o Only one grit channel is equipped with a mechanical
cleaning device. The second channel must be cleaned
manually.
o The motor operated skimmer and sludge collector on the
#1 primary clarifier was out of service. This problem
occurs frequently due to age of equipment and difficulty
in obtaining parts. Excessive scum and solids collected
and remained for days on the effluent weirs of both
primary clarifiers.
e According to a KY-DNR.EP report (May 13-14, 1975), the
recirculation of plant effluent back to TF #2 must be
discontinued when the flow from primary clarifier 02
exceeds about 600 gpm. This is done to prevent flooding
the primary clarifier and backing the flow up and out
of the overflow by-pass. In addition, the recirculation
pump tor the #2 TF is temporarily out of service.
e> Trickling filter #1 contained no zoogleal film and the
growth was sparse on TF #2. Distributor arras on both
filters were not level and many nozzles were missing
or completely plugged. Filter flies were abundant.
e Approximately one month prior to the study, the primary
digester was pumped too low and the gas seal was broken.
The digester was being slowly refilled. The recirculation
pump in the primary digester was out of order.
o Industrial wastes appear to have a significant detrimental
effect on plant operation as evidenced by the lack of
zoogleal growth on either trickling filter, BOD5/COD
ratio's, large range of pH values, and high concentrations
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of heavy metals in the plant influent and digester.
& The facility was under-staffed.
o Ceneral housekeeping was poor.
RECOMMENDATIONS
Based on observations and data collected during the study, it is
recommended that the following measures be taken to improve treatment
and plant operation:
HEADWORKS
q Mechanically cleaned bar screen shoes should be
removed and properly mounted.
o Screens on each grit channel should be cleaned
regularly to prevent water backing up into the
throat of the Parshall flume.
g The comminutor on the right grit chamber should
be repaired in order that sustained, reliable
operation is accomplished.
© The left grit chamber should be equipped with a
mechanical cleaning device and a comminutor.
© Grit and detritus collected from the grit chamber
screens should be removed and buried regularly.
PRIMARY CLARIFIER
o The motor operating the skimmer and sludge scrapper
on the #1 primary. _clar.if ier._should_b.e...repaired, or
replaced.
e> The overflow weirs on both primary clarifiers should
be cleaned daily.
TRICKLING FILTERS
g The trickling filter distributor arms should be
kept level and all nozzles cleaned.
o All nozzles on the trickling filter distributor
arms which are not operating properly should be
replaced.
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SECONPARY CLARIFIER
o A new sludge pump for the secondary clarifier should
be installed immediately.
e The apparent blockage in the pipe line between the #1
primary clarifier and trickling filter should be loca-
ted and eliminated.
MAINTENANCE AND SAFETY
g A routine housekeeping and maintenance schedule should
be initiated and maintained.
© Grass cutting and trimming should be Eiaintained completely
around all units and buildings including grit chamber and
final clarifier.
o The wooden walkway to the digester is hazardous and
should be rebuilt.
o Permanent stable steps ixito the bar screen house should
be constructed.
© Safety gratings should be placed over the top of the
Parshall flume and stilling wells.
© Discarded equipment and parts left laying around the
grounds and in the bar screen house should either be
stored or thrown away.
© Walkway and safety rails on the secondary clarifier
should be painted.
LABORATORY-
o Chemical analyses at the wastewater treatment plant
should be done according to "EPA Methods for Chemical
Analysis of Water and Wastes."
o When performing dissolved oxygen and BOD analyses,
some type of stirring mechanism should be used with
the DO probe.
o Improved temperature control on the muffle furnace is
needed.
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OTHER
o All industries discharging to the municipal sewerage system
should be investigated and their discharges characterized.
Those industrial dischargers whose wastes are found to be
incompatible with, plant operations should be required to
provide adequate pretreatment or remove their wastes from
the sewerage system.
e One or two additional personnel should be hired to operate
the plant.
o Chlorine should be applied more uniformly throughout the
clarifier instead of along a single radius.
o .Construction of a chlorine contact chamber should be con-
sidered in order to reduce chemical costs and improve
chlorine disinfection.
o Drainage from the drying beds should be recycled to the
head of the plant.
TREATMENT FACILITY
TREATMENT PROCESSES
A schematic diagram of the Danville Wastewater Treatment Plant (WTP)
is presented in Figure 1, and the design data are enumerated in Table I.
The original plant was constructed in 1941 and consisted of the //I primary
clarifier and trickling filter (TF), secondary digester and final clarifier.
The additional units were constructed in the expansion which was completed
in 1960.
The 1.8 mgd trickling filter plant serves approximately 13,240 persons
in Danville. . Plant personnel reported-that- industrial wastes constitute
approximately 10 percent of the total plant flow with a population equivalent
of about 5,100 (based on BOD^).
The grit chamber is divided into two parallel basins equipped with
proportional weirs designed to maintain a constant velocity through the
chambers. The right grit chamber is equipped with a comminutor and
mechanical cleaning device; the left chamber contains neither.
Flow from the gi'it chamber combines with return sludge from the final
clarifier and is split to the two primary clarifiers operated in parallel.
Hydraulic capacity of the primary clarifiers- requires 38 and 62 percent
of the incoming flow to be split to the #1 and #2 clarifiers, respectively.
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FIGURE I
WASTEWATER TREATMENT PLANT
DANVILLE, KY.
Sludge
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TABLE I
DESIGN DATA
WASTEWATER TREATMENT PLANT
DANVILLE, KENTUCKY
Grit Channels
Number 2
Width 2.0 ft.
Depth 1.25 ft.
Type Both equipped with proportional weirs;
one channel mechanically cleaned and
contains a 3/4-hp coiraninutor; second
channel manually cleaned, contains bar
screen.
Primary Clarificrs - Circular Center Feed
Unit #1
Diameter
Area
Weir length
Volume
40 ft.
1,257 sq. ft.
125 ft.
63,:000 gallons
Capacity @ 800 gpd/sq.ft.
Capacity @ 105000gpd/ft.
Capacity @ 2 hrs. detention
= 1.005 mgd
=1.25 mgd
= 0.756 mcd
Unit #2
Diameter
Area
Weir length
Vo lume
Trickling Filters
Number'
Type
Diameter
Area
Depth
Volume
Capacity @ 25 lb BOD/day/1000 cu-ft =
Distributors
Final Clarifier - Circular Center Feed
Capacity @ 800 gpd/sq.ft. = 1.57 mgd
Capacity @ 10,000 gpd/ft. = 1,57 mgd
Capacity @ 2 hrs. detention = 1.35 mgd
2
High Rate
105 ft.
8,659 sq. ft. (.199 ac.)
5.67 ft,
49,096 cu. ft.
1,225 lb BOD
Gravity feed
50 ft.
1963 sq. ft.
]57 ft.
112,900 gallons
Number
Diameter
Area
Weir length
Volume
1
55 ft.
2>375 sq. ft.
172 ft.
142,400 gallons
Capacity @ 800 gpd/sq.ft. = 1.90 mgd
Capacity @ .10,000 gpd/ft. = 1.72 mgd
Capacity @ 2 hrs. detention = 1.71 mgd
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TABLE I - Con't
Digesters
Primary (Unit //1)
Volume 33,300 cu. ft.
Temperature controlled at approximately 90°F by heat exchanger
Digester mixed by recirculating pump
Secondary (Unit //2)
Volume 17,000 cu. ft.
No temperature control or mixing
Drying Beds
Number (new beds) 3
Area (total) 14,100 sq. ft.
Number (old beds) 5
Area (total) 10,000 sq. ft.
Total Drying Area 24,100 sq. ft.
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The two trickling filters are designed as high rate filters. A
700 gpm pump for each filter recirculates final effluent back to each of
the trickling filters. Distributor arms operate by gravity under approx-
imately a 3.7-foot head.
Effluent from the trickling filters discharges to the final
clarifier for clarification and chlorination. Approximately 100 pounds/
day of liquid chlorine is discharged at various points along a single
radius jn the final clarifier. A separate chlorine contact chamber is
not provided.
Sludge is discharged to two anaerobic digesters operated in series.
The primary digester is mixed and heated by a recirculation pump and
heat exchanger. The primary fuel for the heat exchanger is digester gas.
The secondary digester is not mixed or heated and serves primarily as a
holding tank prior to discharging sludge to drying beds. Supernatant
from the //2 digester discharges back to the primary clarifier splitter
box.
PERSONNEL
The plant is staffed by one Class IV operator who works eight hours
per day (7am-4pm). Any additional help must be drawn from other sources,
primarily lift station maintenance men, two cf which have a Class III
operators certification. The city has had problems hiring and retaining
adequate staff to onprate the plant. Hired help frequently quit, leaving
the plant understaffed.
STUDY RESULTS AN]) OBSERVATIONS
A complete listing of all analytical data is presented in Appendix
A. Study methods are presented in Appendix B. Significant results and
observations made during the study are presented in the following sections.
FLOW
Raw influent flow was determined by use of the facility1 s 12-incli
Parshall flume, recorder and totalizer. The flow recorder was not oper-
ating at the beginning of the study but was calibrated and placed in
operation by the study team. A Stevens stage recorder was also installed
on the Parshall flume to check the plant's flow recorder and totalizer,
which were subsequently determined to be operating satisfactorily. Vari-
ation of wastewater flow into the plant is presented in Figure 2. The
average hourly flew varied from approximately 0.55 mgd to 2.0 mgd.
Hov/ever, instantaneous flows as high as 2.4 mgd were observed. When the
flow reached approximately 2.4 mgd, excess wastewater by-passed treatment
via a standpipe located in the splitter chamber following the grit chamber.
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FIGURE 2
FLOW AND pH
DANVILLE, KENTUCKY
M N M N ' M N
S/iSl 8/20 8/21 8/22
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Flow from each of the trickling filters was determined by measuring
flow depth in the discharge pipe from each filter and using Kutter's
formula for vitrified clay pipe. The instantaneous flow and percent of
total flow from each filter is presented in Table II.
TABLE II
Trickling Filter Flow
Date
Time
TF #1
TF if 2
(1975)
(24-hr. clock)
(mgd)
(%)
(mgd)
(%)
8/19
1030
1.58
68
0.73
32
8/20
1030
1.74
66
0.90
34
8/20
1130
1.70
61
1.1
39
8/21
1145
1.09
50
1.09
50
8/21
1430
1.09
46
1.28
54
8/22
0920
1.09
48
1.17
52
The different hydraulic capacities of the two primary clarifiers
(Table I) results in an unequal flow split to the remainder of the plant.
Theoretically, 38 percent of the raw flow into the plant is split to the
if1 clarifier and 62 percent to the #2 clarifier, resulting in unequal
hydraulic loading to the two trickling filters. This split is accomplished
by two flat gates in the splitter box located above the two clarifiers.
According to a May 13-14, 1975 report by Mr. Paul K. Wood, Principal
Sanitary Engineer with the KY-DNREP, when the flow from the if 2 clarifier
exceeds 600 gpm, recirculation to the if2 trickling filter must be dis-
continued-due to flooding of the if2. primary, clarifier.. . _A possible_cause
is blockage in the pipe line connecting the clarifier and trickling filter.
WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES
A chemical description of "the influent, effluent and percent reduction
through the plant is presented in Table III.- Figures 3 and 4 depict effi-
ciency of individual units. The results presented in Table III indicate
poor B0D5, COD and TSS removal and negligible nitrification. The BOD/COD
ratio of .32 indicates a significant quantity of industrial waste. The
concentration of metals (Pb, Zn and Cu) entering the plant is also indica-
tive of industrial wastewater discharges.
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TABLE III
Waste Characteristics and Removal Efficiencies
Parameter
BODc
COD
TSS
TKN
NH
3
NO3-NO2
Total-N
Total-P
Lead
Zinc
Copper
Temp. Range (°C)
pH range (std. units)
Turbidity (JTU)
Influent
(mg/1)
142
446
314
24
16.2
5.7
29.7
9.0
3.-45
2.63
1.19
23-24
3.0-9.0
Effluent
(rag/1)
39
212
126
19.6
13.5
6.1
25.6
3.8
1.96
.54
.72
22.0-23.5
6.7-7.3
43
% Reduction
72
52
60
18
17
N/A
14
58
43
79
39
N/A
N/A
The hourly influent pH variation during a continuous 42-hour period
is presented in Figure 2. The pH fluctuated significantly on a number
of occasions for short durations of time. Table IV presents the range
in instantaneous pH observations for the indicated time periods. The
wide range of influent pH values is also indicative of industrial waste-
water discharges.
Date
8/20/75
8/21/75
8/21/75
8/21/75
TABLE IV
Instantaneous Influent pH Variations
Time
0800
0200-0500
1110
1415-1700
£H
5.8
4.6-7.3
5.8
7.0-9.0
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FIGURE 3
TREATMENT EFFICIENCY - NO. I UNITS
DANVILLE, KY.
\
SAMPLE LOCATIONS
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FIGURE 4
TREATMENT EFFI CI ENC Y - NO. 2 UNITS
DANVILLE, KY.
\
SAMPLE LOCATIONS
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TABLE IV (Cont.)
Instantaneous Influent pH Variations
Date Time pH
8/21/75 2200-2400 7.1-8.5
8/22/75 0600-0730 3.0-6.4
On August 20 at 8:00 am, the plant influent contained flocculent
solids (settleable solids - 24 ml/1) with a pH of 5.8. This was probably
due to batch industrial discharges.
HEAD WORKS
All wastewater entering the plant passess through a mechanically
cleaned bar screen. The screen had been dovm for repairs since August 18,
but was repaired and placed back in service on August 20. In addition, the
shoes on the mechanical cleaning device were installed backwards resulting
in screened material being pushed through the bars rather than being
removed. Proper installation of the shoes began on August 20 and when
completed should result in an immediate improvement in the bar screen
efficiency.
The ccmminutcr on the right channel of the grit chamber continually
overheated and shut off. Consequently, the comminutor blocked flow into
the right grit channel, increased flow in the other channel, and allowed
large solids to enter subsequent treatment units. An electrician tempor-
arily repaired the unit during the study. The existing comminutor should
be repaired for permanent sustained use and the remaining grit channel
also equipped with a comminutor. A new comminuter, acquired approximately
one year ago, has been laying unused since delivery. There is some
question concerning how it is to be mounted and used. The equipment
manufacturer should be contacted.
The flow through velocity in the left and .right parallel grit channels
was determined and is presented in Table V. The comminutor was located
at the entrance to the right grit channel. The difference in flow through
velocities in the two channels was significant. Recommended velocities
for grit chambers range from 0.7 to 1.4 feet per second (fps).jk/
TARLE V
Grit Channel Velocities
8/19 8/20
Right Channel (fps) .67 .94
Left Channel (fps) 2.2 2.0
1/ "Operation of Wastewater Treatment Plants," by Sacramento State
College for the U.S. Environmental Protection Agency, Technical Training
Grant No. 5TT1-WP-16-03, 1970.
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PRIMARY CLARIFIER
The motor operating the skimmer and sludge collector on the /Al
primary clarifier was, out of service. According to plant personnel,
the motor is old, worn out, and new parts are difficult to obtain.
Excessive solids collected along the overflow weirs of both primary
clarifiers clogged the v-notches and overflowed into the trickling filters.
These weirs should be cleaned daily and the weirs brushed frequently.
Primary clarifier efficiencies are depicted in Figures 3 and 4.
Clarifier overflow characteristics are based on grab samples while raw
influent characteristics are based on 24-hour composite samples. Removal
efficiencies for each primary clarifies are listed in Table VI. Typical
BOD3 and TSS removal efficiencies for primary clarifiers are 35 and 60
percent, respectively.
TABLE VI
Primary Clarifier Removal Efficiencies (%)
BODs COD TSS
Clarifier //I 32 43 71
Clarifier //2 0 42 62
The BODn; concentrations from clarifier #2 on the two days of sampling
were 78 and 213 mg/1. The latter value significantly affects the average
removal efficiencies listed in Table VI.
TRICKLING FILTER
The trickling filters are designed as high rate filters (typical
hydraulic loading range 8.7-44 mgacLi/); however, the approximate dosing
is 8 (mgad) for TF//1 and 5 mgad for TF//2. The poor mechanical condition
of the trickling filters and final clarifier inhibited optimization of
the filter operation. However, consideration should be given to instal-
ling pumps to increase filter recirculation capacity.
The two trickling filters contained little or no zoogleal film. On
a reconnaissance to the plant on July 22, 1975, TF it 1 contained no zooglea
but TF #2 did. Plant personnel indicated that a local industrial discharge
killed the growth in the filters the week previo\is to the study. Enzymes
(Hydraulic Enzymes Bacteria Complex) were added to the influent of each
filter to aid in reestablishing zoogleal growth; growth had improved some
on TF it2 by August 22 but there was no improvement on TF ?'/l. Trickling
1/ "Sewage Treatment Plant Design," ASCE - Manuals of Engineering
Practice -.No. 36.
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Filter //I had been shui; down, until approximately l1^ weeks before the study
while waiting for a consultant to look at the ill primary clarifier.
Distribution of primary effluent onto the filters was poor. Approxi-
mately 56 and 76 percent of the nozzles on TF il 1 and TF #2, respectively,
were completely or partially plugged. Many other nozzles.were missing.
Parts were distributed on the filter bed and the filter bed wall. The
cap on the end of one distributor arm was missing. The distributor arms
on both filters were out of level.
Trickling filter removal efficiencies are depicted in Figure 3 and 4.
Removal efficiencies accomplished by each filter of primary effluent is
presented in Table VII.
TABLE VII
Trickling Filter Removal Efficiencies (%)
BOD 5
COD
TSS
TF
//I
75
63
49
TF
//2
60
36
0
All parameters measured were higher out of TF #2 than TF it 1. Settle-
able solids -results indicate sloughing from TF //2. On two or the three
days of sampling, the TSS out of TF #2 was greater than the TSS entering
the filter.
Filter flies were prevalent around the plant. Shrubbery, weeds, and
tall grass provide a natural sanctuary for filter flies. Good grounds
maintenance and cleanup practices will help to minimize fly problems.
FINAL CLARIFIER
The original diaphram sludge pump burned out approximately two
years ago and a temporarily installed centrifugal pump has proved to be
inadequate. Consequently, excessive sludge-has accumulated and compacted
causing anaerobic, conditions which were evidenced by bubbles and frequent
balls of solids floating to the clarifier surface.
The depth of the sludge blanket (DOB) below the water surface in the
final clarifier was approximately 6.5 feet at all points along the radius.
Consequently, the sludge blanket depth varied from about 1 foot at the
outer wall to 3 feet at the center. The solids concentration of the sludge
was 36 percent as determined by centrifuge (approximately 3 percent dry
weight).
Chlorination of plant effluent: was accomplished by discharging 100
pounds/day of chlorine at various points along a single radius in the
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final clarifier. A chlorine residual was observed each day of the study.
Distribution of chlorine would be more efficient if it -was applied at
various points throughout the entire clarifier instead of along a single
radius. A significant reduction in chlorine usage and chemical costs
could be achieved by constructing a separate chlorine contact basin.
Two pumps, rated at 700 gpm each, recirculate effluent back to the
high rate trickling filters. However, the recirculation pump to the #2
IF was out of service for repairs.
Figures 3 and 4 indicate an increase in BOD^, TSS and COD from the
effluent of the trickling filters to the final clarifier effluent. This
phenomenon is attributable to the. anaerobic conditions resulting in gas
production and subsequent resuspension of previously settled solids.
DIGESTER AND DRYING BEDS
During the study, the anaerobic digesters were not operating under
typical conditions. The primary digester was being refilled after being
pumped too low and breaking the gas seal. In addition, the recirculation
pump was broken which prohibited mixing and heating of the digester
contents.
The secondary digester is used solely as a holding'tank, prior to
discharging sludge to the drying beds. The plant operator stated that
sludge handling has never been a problem; the digesters have worked
properly, sludge dries quickly and drying bed area is sufficient. Filtrate
from the drying beds flows untreated to the receiving stream.
Analytical results of samples collected from the digesters are pre-
sented in Appendix A. These data are not representative of the total
digester contents since the digester was unmixed.
Lead, zinc and copper are accumulating in the digester as indicated
by analysis (Appendix A) of sample DIB obtained from_ the bottom . of__the
primary digester. Cooper and zinc are quite toxic, and depending on the
concentration of sulfides, could adversely affect digester performance.
SAFETY AND MAINTENANCE
Problems observed relating to safety and maintenance were:
o The stairway to the second floor of the laboratory was cluttered
with miscellaneous items.
o The wooden walkway by the digester was rotten.
e Stacked concrete blocks used as steps into the bar screen house
and top of grit chamber were unstable.
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o Safety gratings were missing over the top of the Parshall flume
and stilling wells.
© Discarded equipment and parts were left laying all over the
grounds and in the building housing the bar screen and flow
meter.
e The garbage can and bucket used to collect screened material
are emptied infrequently.
o The walkway and safety rails on secondary clarifier were
rusting and in general need of paint.
e The weirs on both primary clarifiers contained significant
quantities of ]arge solid "globs", paper and other materials.
These should be inspected daily and cleaned as needed.
o Weeds were observed in both the new and old sludge drying beds.
o The effluent wells from both trickling filters contained a
large number of filter flies. Routine hosing down of these
chamber walls would help control filter flies around the plant.
o Grass and weeds around the plant were not cut. Grass cutting
and Lxiimuiug should be maintained completely around ail urrius
and buildings including grit chamber and final clarifier. In
addition to improving working conditions, this should help
control filter flies around the plant.
o Grit collected from the grit chamber was shovelled into the
weeds adjacent to the chamber. This material along with
detritus collected by the screens should be buried in the
landfill located adjacent to the plant.
LABORATORY
In order to make space and equipment available for EPA personnel,
chemical testing by the plant operator was temporarily discontinued.
Consequently, the investigators were not able to observe and make first
hand comments and suggestions concerning laboratory procedures.
A substantial temperature difference was observed between the BOD
incubator temperature indicator and the actual temperature. Placing a
thermometer in water inside the incubator should be standard practice.
The plant laboratory was equipped with a Y.S.I, dissolved oxygen
meter; however, no provisions were made for stirring the sample. It is
necessary to maintain a velocity by the probe to prevent erroneous
readings. In a BOD bottle, a magnetic mixer can be used, but this can
cause errors if not used carefully. A factory equipped probe with stir-
ring device is another possibility.
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Th e muffle furnace used- for volatile solids analysis was controlled
by a proportional timer rather than by a thermostate. This requires very
close attention and frequent adjustment. A muffle furnace with an auto-
matic thermostat control would relieve the operator for other duties.
A standard set of weights is used to check the analytical balance.
This quality control procedure is encouraging and worthy of note. The
EPA manual entitled "EPA Methods for Chemical Analysis of Water and Wastes"
(EPA 625/6-74-003) is being sent to Mr. Paul Collins, plant operator.
PERSONNEL
Consideration should be given to the proper levels of staffing at the
Danville Wastewater Treatment Plant. Staffing factors include plant site
size, relative positions of each unit to the control center, complexity of
operation, laboratory testing requirements and number of shifts. The follow-
ing man years of effort are recommended as a minimum for this plant by
categories of work.—'
Category Man Years
Management/Supervision 0.5
Laboratory 0.3
Operations of Plant 1.4
Maintenance of Plant 0.9
Other Laborers 0.4
Other Clerical 0.1
Total 3.6
Obviously, one person cannot be assigned to each individual task as
indicated in the table. The duties will have to be combined and assigned
to staff members an the plant. However, it is recommended that the labor-
atory work be emphasized. These staffing recommendations are for the plant
only. Collection system activities require additional personnel.
_1/ Estimating Staffing for Municipal Wastewater Treatment Facilities,
EPA Contract No. 68-01-0328, March 1973.
-------
APPENDIX A
CHEMICAL LABORATORY DATA
/ / / / / MA /fA /' / / / / ///// /
/ / / / /* A? A // // / / / / / U si I /
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1
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. £
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-------
Appendix A (Cont]
CHEMICAL LABORATORY DATA
DANVILLE. KY
0 St M
SAD
STATION
X ,
H
2 I
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<1 k I TIME
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-------
Appendix A (Cont)
CHEMICAL LABORATORY DATA
DANVILLE, KY
0088
0099
0114
0089
0101
0115
1
; ti l 8
19
75
1500
r / /
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-------
Appendix A. (Cont)
CHEMICAL LAEORA^ORV DATA
DANVILLE, KY
0 fi. M
SAD
STATION
1
i i 1
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75 ! 1500
! 1
7.3't 22° I
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-------
-Apper.di-x-A -(Cont-)- CHEMICAL LABORATORY DATA
-------
-26-
Appendix E
STUDY METHODS
In order to accomplish the stated objectives, the study included
extensive sampling, physical measurements and daily observations. The
plant influent and effluent streams, sample stations I and E, respectively,
were sampled for two 24-hour and one 18-hour periods with .ISCO model
1392-X automatic samplers. Aliquots of sample were pumped at hourly
intervals into individual refrigerated glass bottles which were composited
proportional to flow at the end of each sampling period.
Dissolved oxygen was determined daily at all stations using a YSI
model 51A dissolved oxygen meter.
A Stevens Model F stage recorder was installed on the influent stream
to check accuracy of the installed plant flow meter and totalizer. Also
on August 20, a recording pH meter was installed on the plant influent
to record pH variations throughout the subsequent sampling periods.
Depth of the sludge blanket in the final clarifier was determined
using an optical viewer system.
Instantaneous flows were determined daily on the influent waste stream
at the Parshall flume. Also, trickling filter flows in the discharge
pipes were determined daily using Kutter's formula for vitrified clay pipe.
Imhoff cones and the centrifuge were used daily to determine solids
being discharged from each treatment unit.
Physical observations were made of the operation of individual units
daily.
The mention of trade names or commercial products in this report does
not constitue endorsement or recommendation for use by the Environmental
Protection Agency.
-------
APPENDIX C
o
Oxygen Uptake Procedure
Apparatus
1. Electronic DO analyzer and battle probe
2. Magnetic stirrer
3. Standard BOD bottles (3 or more)
4. Three vide mouth sampling containers (approx. 1 liter each)
5. DO titration assembly for instrument calibration
6. Graduated cylinder (250 ml)
7. Adapter for connecting two BOD bottles
Procedure
1. Collect samples of return sludge, aerator influent and
final clarificr overflow. Aerate the return sludge sample
promptly.
2. Mix the return sludge and measure that quantity for
addition to a 300 nil BOD bottle that corresponds to '.lie
return sludge proportion of the plant aerator, i.e., "->r
a 40% return sludge percentage in the plant the ar/.M. l
added to the test ;'OD bottle is:
- I?£ "80 ml
i.0 + .4 1.4
3. Carefully add final clarificr- overflow to /ill. the BOD
bottle and to dilute the return sludge to the plant aerator
mixed liquor solids concentration.
4. Connect the filled bottle and an empty ROD bottle with the
ROD bottle adapter. Invert the combination and . shake
vigorously while transferring the contents. Rc-invert and
shake again while returning the sample to the original test
bottle. The sample should now be well mixed and have a high
D.O.
5. Insert a magnetic stirrer bar and the previously calibrated
DO probe. Place on a magnetic stirrer and adjust agitation
to maintain a good solids suspension.
6. Read sample temperature and DO at test time t=0. Read and
record ¦ the DO again at 1 minute intervals until, at least 3
consistent readings for the change in DO per minute are
obtained (A DO/min). Check the f inal sample temperature.
This approximates sludge activity in terms of oxygen use
after stabilization of the sludge during aeration (unfed
sludge activity).
-27-
-------
Appendix C (C-ont)
7. Repeat steps 2 through 6 on a replicate sample of return
sludge that has been diluted with aerator influent (fed
mixture) rather than final effluent. This A DO/minute
series reflects sludge activity after mixing with the new
feed. The test results indicate the degree of sludge
stabilization and the effects of the influent waste upon
that sludge.
The load factor (LF), a derived figure, is helpful in evaluating
sludge activity. It is calculated by dividing the DO/min of fed
sludge by the DO/min of the unfed return sludge. The load . ratio
reflects the conditions at the beginning and end of aeration.
Generally, a large load factor means abundant, acceptable feed under
favorable conditions. A small LF ineans dilute feed, sick sludge,
poorly acceptable feed, incipient toxicity, or .unfavorable
conditions. A negative LR indicates that something in the wastewater
shocked or poisoned the "bugs."
(3) Taken from "Dissolved Oxygen Testing Procedure," F. J. Ludzack
and script for slide tape XT-43 (Dissolved Oxygen 'Analysis
Activated Sludge Control Testing) prepared by F. J. Ludzack. NEl'C,
Cincinnati.
-28-
------- |