TECHNICAL ASSISTANCE PROJECT
AT THE
6AFFNEY, SOUTH CAROLINA
WASTEWATER TREATMENT PLANT
SEPTEMBER 1975
Environmental Protection Agency
Region IV
Surveillance arte? Analysis Division
Athens, Georgia
-------
TECHNICAL ASSISTANCE PROJECT
AT THE
GAFFNEY, SOUTH CAROLINA
WASTEWATER TREATMENT PLANT
September 19 75
LffesTuj Regie® IV
3 aV&e-d&a Ageaey
3Q Oy.:.7'::md Sired
vtr-
^s
Environmental Protection Agency
Region IV
Surveillance and Analysis Division
Athens, Georgia
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CONTENTS
Page
INTRODUCTION 1
SUMMARY 2
RECOMMENDATIONS 3
TREATMENT FACILITY 5
TREATMENT PROCESSES 5
PERSONNEL 5
STUDY RESULTS AND OBSERVATIONS 8
FLOW 8
WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES 8
DISSOLVED OXYGEN 10
AERATION BASIN 10
CLARIFIERS 12
RETURN SLUDGE 15
CHLORINE CONTACT CHAMBER 16
DIGESTER AND DRYING BEDS 16
EXAMINATION OF MICROSCOPIC ORGANISMS 16
OXYGEN UPTAKE RATES 17
LABORATORY 18
APPENDICES
A. CHEMICAL LABORATORY DATA 20
B. GENERAL STUDY METHODS 24
C. OXYGEN UPTAKE PROCEDURE 25
D. DECHLORINATING PROCEDURE 27
FIGURES
1. PEOPLES CREEK STP 6
2. FLOW AND pH 9
3. SETTLOMETER TEST 13
TABLES
I. DESIGN DATA 7
II. WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES 8
III. AERATION BASIN DISSOLVED OXYGEN PROFILES 11
IV. TURBIDITY OF CLARIFIER EFFLUENTS 14
V. ACTUAL AND DESIGN PARAMETERS FOR SECONDARY
CLARIFIERS 15
VI. OXYGEN UPTAKE RATES 18
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INTRODUCTION
A technical assistance study of operation and maintenance problems
at the wastewater treatment plant serving Gaffney, South Carolina was
conducted September 22-25> 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 control
authorities. Visits are made to each prospective plant prior to the study
to determine if assisuance is desired and if study efforts would be
productive.
The specific study objectives were to:
o Optimize treatment via control testing and
operation and maintenance modifications,
© Determine influent and effluent waste characteristics,
o Assist laboratory personnel with any possible
laboratory procedural problems, and
© Compare design, and current loadings,
A follow-up assessment of plant operation and maintenance practices
will be made at a later date. This will be accomplished by using data
generated by plant personnel and, if necessary, additional 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 South Carolina Department of Health and
Environmental Control is gratefully acknowledged. The technical assistance
team is especially appreciative of the cooperation and assistance received
from Gaffney Wastewater Treatment Plant personnel.
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SUMMARY
The Peoples Creek Wastewater Treatment Plant is an extended aeration
activated sludge facility designed for an average flow of 3 million
gallons per day. The treatment plant was expanded to the present
configuration in 1970. Approximately 70 percent of the flow is from
industrial sources, primarily from printing and finishing textile mills.
The population served is 5,590.
The plant is well staffed and maintained, and the laboratory facilities
are exceptionally good. The primary difficulty encountered is sludge
bulking in the secondary clarifier. This problem appears to begin on a
regular basis in August and continues through fall. During the remainder
of the year, bulking occurs at irregular and infrequent intervals.
An additional problem is insufficient sludge handling facilities.
Efficient operation of the wastewater treatment plant is impaired by the
inability to properly treat and dispose of the sludge.
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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:
o The influent flow should be split and introduced under
both the ill and //2 aerators.
© All three fixed-mount aerators should remain on at all
times. Possibly the two stand-by floating aerators should
also be brought into continuous service.
o An intensive dissolved oxygen study of the aeration basin
should be performed to determine the amount and placement of
additional aerators required to maintain at least 2 mg/l
dissolved oxygen throughout.
o The addition of chlorine or hydrogen peroxide to the
clarifier influent should improve sludge settleability.
Jar tests should be used to determine chemical additions to
optimize sludge settleability and supernatant clarity.
© Various methods to upgrade the final clarifier, e.g.
settling tubes, should be investigated.
e Sludge from the chlorine contact chamber should be pumped
directly to the digester.
o Digester supernatant should be pumped back to the
aeration basin.
Based on observations during the study, the following are some
recommendations related to the laboratory:
© At least two and preferably three dilutions should be made
on the influent samples for the BOD^ test.
o Distilled water for making dilutions in the BOD^ test should
contain "Formula C" reagents as per "Standard Methods for the
Examination in Water and Wastewater," 13th Edition. Blanks of
this solution should be run daily.
e Chlorinated effluent samples should be dechlorinated before
BOD^ analysis. A simple and effective method for this is
included in Appendix D.
-3-
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e It is suggested that the Chemical Oxygen Demand (COD)
determination be included as a control test. The method
for this is also found in "Standard Methods for the
Examination of Water and Wastewater," 13th Edition.
-4-
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TREATMENT FACILITY
TREATMENT PROCESSES
A schematic diagram of the 3 mgd Peoples Creek Wastewater Treatment
Plant (WTP) is presented in Figure 1. Design data is enumerated in
Table I. The original, plant was constructed in 1953 and consisted of
clarification and a trickling filter. The facility was modified and
expanded to the present extended aeration system in 19 70. A grit
chamber constructed with the original plant is still intact but not used
due to the low grit content of the raw wastewater.
All wastewater reaches the plant by gravity and flows directly into
the aeration basin under the ?72 aerator. The aeration basin contains three'
75-hp fixed mount aerators. The //I aerator runs continuously; the #2 and
//3 aerators are controlled by a timer, on 40 minutes and off 20 minutes.
Two 45-hp floating aerators are available as stand-by units.
Flow from the aeration basin is divided in a splitter box via two
flat gates and flows to two secondary clarifiers operated in parallel.
Sludge from the chlorine contact chamber is pumped back to the splitter
box via two pumps rated at 50 gpm and 230 gpm.
Return sludge from the two clarifiers is pumped to the head of the
plant by two sludge pnnipy rated at 1,000 gps- each. A third 1,000
gpm sludge pump is available as a spare.
Approximately 100,000-120,000 gallons per day of sludge is wasted
to the digester, three days per week. During sludge wasting, no sludge
is returned to the aeration basin. The covered digester is operated as
a holding basin until the sludge can be pumped to the drying beds. The
digester is not operated as an anaerobic digester due to insufficient
capacity and lack of heating capability. Supernatant from the digester
is pumped to the //I clarifier. Filtrate from the drying beds flows directly
into Peoples Creek.
PERSONNEL
The plant is staffed by six men whose duties are split among four
wastewater treatment plants. Total weekly man-hours spent at the Peoples
Creek plant is 60. Three of the men hold a Class A, C or D operators
license.
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FIGURE 1
PEOFLE CREEK STP
GAFFNEY, SC
AAo
A2
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TABLE I
DESIGN DATA
PEOPLES CREEK WTP
GAFFNEY, SOUTH CAROLINA
FLOW MEASUREMENT
Type Parshall Flume, recorder, totalizer
Size 18-inch
AERATION BASIN
Number 1
Depth 16 ft.
Volume 400,000 cu.'ft. (2.992 MG)
Aerators 3-75 hp (fixed mount)
2-45 hp (floating)
SECONDARY CLARIFIERS
Number 2
Diameter 60 feet
Area 2,827 sq. feet
Volume 21,200 cu. feet
Depth (mean) 7.5 feel:
Weir Length 217 feet
CHLORINE CONTACT CHAMBER
Area 1,728 sq. feet
Depth (average) 9 feet
Volume 15,552 cu. ft. (.12 MG)
DIGESTER
Number 1
Volume 30,160 cu. feet
No temperature control - operated as holding basin only.
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STUDY RESULTS AND OBSERVATIONS
A complete, listing of all. analytical data and study methods is
presented in the Appendices. Significant results and observations made
during the study are presented in the following sections.
Influent flow was determined by an 18-inch Parshall flume, totalizer
and recorder. The flume and recorder were in good repair and accurate.
Influent raw waste and return sludge flow rates during the study
period are presented in Figure 2. The average daily influent flow for
the study period was 2.33 mgd; mean hourly flows varied from 1.4 mgd
to a maximum of 3.5 mgd, which occurred during a rain. The annual
average daily flow is 1.83 mgd.
Approximately 70 percent of the influent wastewater flow is from
industrial sources, many of which operate 24- hours per day. Consequently,
flow during a 24-hour period does not vary significantly.
Return sludge flow (RSF) from the final clarifiers to the head of the
plant is varied according to the mixed liquor suspended solids (MLSS)
concentration in the aeration basin. The RSF was fairly constant during
the study period at approximately 2.4 mgd. Return sludge flow is con-
trolled by a butterfly valve and magnetic flow meter.
WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES
A chemical description of the average influent, effluent and percent
reduction through the plant during the study period is presented in Table II.
FLOW
TABLE II
WASTE CHARACTERISTICS AND REMOVAL EFFICIENCIES
PARAMETER
INFLUENT
(mg/1)
EFFLUENT
(mg/1)
% REDUCTION
bod5
COD
TSS
TVSS
278
761
137
77
36
177
93
71
87
77
32
8
35
58
85
TKN-N
nh3~n
Kin _wn -n
TOTAL-N
9.43
9.27
6.2
. 16
6.13
3.84
0.92
2.29
3.2
.14
.23
3.8
16
0
54
Cu
Zn
.13
.50
-8-
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FIGURE 2
FLOW AND pH
GAFFNEY. SC
Total raw
waste flow.
Return sludge
flow.
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When bulking was not occurring, turbidity of the final clarifier
effluent ranged from 8-19 standard turbidity units (STU). However,
during bulking, turbidity ranged from 90-600 STU. BOD and solids reduc-
tion were significantly affected by the washout of solids from the
clarifiers. Effluent TSS and TVSS concentrations indicate the volatile
nature of the bulking sludge. The influent BOD/COD ratio of 0.36 shows
the influence of industrial wastes. Nitrogen analyses indicate excellent
nitrification occurring through the treatment facility. The metals
chromium, cadmium, and lead were not found in significant quantities.
Hourly influent pH variations during a continuous 48-hour period
are presented in Figure 2. The pH did not vary significantly and does
not present any problems at the. plant.
DISSOLVED OXYGEN
A profile of dissolved oxygen (DO) concentrations at various locations
in the aeration basin is presented in Table III. During two days of
observations, the DO ranged from 0.4 to 1.2 mg/1 when all three aerators
were on. The highest DO concentrations were measured approximately 20
feet from the basin influent; the influent wastewater had a DO concentra-
tion of 3.4 mg/1.
When two aerators were off, DO•concentrations of zero or near zero
were measured. At station A-8, a DO concentration of 0.8 mg/1 was measured
while the //2 aerator was on, but dropped to 0.1 mg/1 30 seconds after
shutting the #2 aerator off.
As indicated in Table III, dissolved oxygen levels were generally low
in the aeration basin. According to "Process Design Manual for Upgrading
Existing Wastewater Treatment Plants", US-EPA, Technology Transfer, October
1974, low DO levels have been found to be the major cause of sludge bulk-
ing. The EPA design manual recommends a DO concentration in aeration
basins of 2-4 mg/1.
These observations indicate that all three fixed-mounted aerators should
run continuously and possibly the two floating aerators should be brought
into service. A more intensive DO study of the aeration basin will be
necessary to determine the amount of aeration required to maintain an
acceptable DO concentration.
AERATION BASIN
Grab samples were taken at the point of discharge from the aeration
basin to the clarifiers (Station A3). Settlometer, suspended solids,
volatile suspended solids and percent total solids by centrifuge tests
were run on each sample.
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TEMP.
DATE TIME 'STATION °C
9/231/ 1:30 PM A-3 23
A-4 23
A-5 23
A-2 23
A-l 23
A-6 23
9/24^ 2:30 PM
9/24
3:00 PM
5
3:00 PM
3:00 PM
A-7
A-8
A-8
A-S
A-7
1.0
0.6
0.4
1.0
1.2
0.6
0.0
0.1
0.8^
0.1—7
0.0^
TABLE III
AERATION BASIN
DISSOLVED OXYGEN PROFILES
CAFFNEY, SC
—2
0.9
0.5
0.4
1.1
0.6
0.0
0.0
~3~
0.9
0.5
0.3
0.9
0.0
0.0
0.8
0.6
0.4
1.0
0.5
0.0
0.0
DEPTH (FT.)
0.5
0.4
0.8
0.0
0.0
6
0.8
0.5
0.4
1.0
0.5
0.0
0.0
0.5
0.8
0.8
0.5
1.0
0.4
9 10 n 12 1;
0.8
0.5 0.4 0.4 0.4 0.:
0.7
0.4
0.7
0.4
1/ - All three aerators on.
2] ~ Aerators //2 and if3 off.
3/ - Aerator //2 on.
4/ - Thirty seconds after aerator //2 shut off.
5/ - Aerator if 3 off.
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The average MLSS and mixed liquor volatile suspended solids (MLVSS)
during the study period were 3036 and 2340 mg/1, respectively. The
percent solids as determined by centrifuge ranged from 5.0 to 5.5 percent.
Settlometer test .results are presented in Figure 3 and Appendix A.
These data indicate the poor settling characteristics of the mixed liquor.
The volume of settled mixed liquor sludge was 62 percent after 60 minutes
of settling and the resulting supernatant was relatively clear. The aver-
age sludge volume index (SVI) for the study period was 260, also indicative
of a poor settling activated sludge.
A possible explanation of the different settling rates exhibited by
the top two curves in Figure 3 is the lower solids concentration of the
wastewater flowing over the weirs. Additional settlometer tests were
run on the bulking sludge passing over the secondary clarifier weirs and
on the same bulking sludge after the addition of chlorine. These data
are also presented in Figure 3 and reveal that the addition of chlorine
markedly improves settling. This indicates that the addition of chlorine
or hydrogen peroxide may control the sludge bulking. Jar tests could
be utilized to determine chemical additions to optimize sludge settleability
and supernatant clarity.
Sludge age calculations using a MLSS concentration of 3036 mg/1, an
influent TSS of 137 mg/1 and an average flow rate of 2.33 mgd indicated
a sludge age of 29 days. This sludge age is reasonable for an extended
aeration activated sludge system.
The food to micro-organism ratio (F/M) was calculated to be .09 and
.25 on a BOD and COD basis, respectively. These values were within the
recommended range for extended aeration systems.
The geometry and influent location in the aeration basin does not
lend itself to complete mixing and short-circuiting may be taking place.
A more efficient method of introducing influent wastewater to the aera-
tion basin would be to split the influent flow and introduce it under
both the //I and #2 aerators.
CLARIFIERS
Throughout the study period, either one or both clarifiers were
bulking, beginning about mid-morning. Usually one clarifier would begin
bulking followed by the. other a short time later. Results of samples
analyzed for turbidity are presented in Table IV.
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FICURE 3
SETTLOMETER TEST
R f-1 Aeration basin mixed liquor
(?) Q Bulking sludge after chlorination
— Bulking sludge over clarifier weir
Settling Time (Minutes)
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TABLE IV
TURBIDITY OF CLARIFIER EFFLUENTS
Date
Turbidity (STU)
Station
(1975)
Time
Initial
30-min. Settling
E-l
9/22
1530
96
13
E-l
9/23
0945
12
8
E-l
9/23
1435
250
50
E-l
9/24
0830
13
12
E-l
9/24
1315
400
70
E-l
9/25
0845
11
10
E-l
9/25
1330
180
—
E-2
9/22
1530
19
21
E-2
9/23
0945
15
12
E-2
9/23
1435
8
7
E-2
9/24
0830
17
17
E-2
9/24
1315
90
60
E-2
9/25
0845
11
10
E-2
9/25
1330
COO
—
Clarifier effluents were characterized by a turbidity of 90-600 STU while
bulking. When bulking was not occurring the turbidity range was 8-19 STU,
which is still a little high for a well operating secondary clarifier.
Turbidity data after 30 minutes additional settling indicate that
increased clarifier capacity would improve the effluent.
Physical observations during clarifier bulking revealed strong
currents at various points along the effluent weirs, excessive turbulence
and "boiling" of solids along the outer baffle following the sludge scraper,
and turbulence around the effluent pipe located approximately 18 inches
below the water surface.
Settlometer results (Figure 3) on samples collected from the clarifier
effluents, when bulking was occurring, show an increase in settleability
as compaired to samples collected from the aeration basin mixed liquor.
The solids wasted over the weir during bulking are the young, actively
growing organisms which should be retained in the system. The sludge
being returned is the heavy, less active sludge.
The depth of sludge in the clarifier during the study was always
less than one foot. Sludge floe was dispersed throughout the depth and
was observed to be moving quite rapidly in a horizontal plane.
The theoretical and recommended hydraulic loading, solids loading,
and weir overflow rates for final clarifiers following extended aeration
wastewater treatment are presented in Table V. The average daily flow
to the two clarifiers was determined as the average daily flow into the
plant (2.33 mgd) plus the sludge flow from the chlorine contact chamber
(0.4 mgd).
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TABLE V
ACTUAL AND DESIGN PARAMETERS FOR SECONDARY CLARIFIERS
Actual
Recommended
Hydraulic Loading (gpd/sq ft)
Average
Peak
480
690
200-400^ J600-/
8001/
Solids Loading (lbs/day/sq ft)
Average
Peak
Weir Rate (gpd/lin ft)
Detention Time (hrs)
21
5,530
l.fr
20-30—/
501/
3/
<15,000^'
;2 .0-2.5—^
_1 / "Process Design Manual for Suspended Solids Removal", US-EPA Technology
Transfer, January 1975.
2J "Standards for Sewage Works" , Upper Mississippi River Board of State
Sanitary Engineers, Revised Edition, 1971.
_3/ "Sewage Treatment Plant Design" American Society of Civil Engineers ,
Manual of Engineering Practice -No. 36, 1959.
_4/ Calculated based on flow rates during the study.
Table V indicates that the final clarifier average hydraulic
loading is at the high end of the recommended rates and well within
the recommended solids loading and weir overflow rates, according
to the referenced design criteria. Observed currents and turbulence
suggests that an excessive volume of liquid flowing through the
clarifiers and/or poor entrance hydraulics is adversely affecting
settleability of a sludge which already has poor settling character-
istics. Clarifier upgrading techniques, such as settling tubes to in-
crease the clarifier capacities, should be investigated.
Sludge is pumped from the chlorine contact chamber back to the
clarifiers during the period when bulking is occurring and increases
the stress on the clarifiers.
RETURN SLUDGE
Sludge from each of the two secondary clarifiers is pumped back to
the head of the plant by two, 1,000 gpm sludge pumps. The rate of return
-15-
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sludge flow is controlled by a butterfly valve and magnetic flow meter.
Return sludge flow was maintained at approximately 2.4 mgd and the
average percent solids in the sludge from each clarifier was approximately
equal (12% by centrifuge). The TSS concentration of the sludge varied
from 5,850 to 10,225 mg/1,
CHLORINE CONTACT CHAMBER
The chlorine contact chamber is a converted secondary clarifier
equipped with sludge removal capabilities. The approximate theoretical
detention time at design flow (3 mgd) is one hour.
Sludge is removed from the chlorine contact chamber by two sludge
pumps, rated at 50 and 2 30 gpm, and pumped to the splitter box to the
two clarifiers. The average percent solids determined by centrifuge
of the sludge was 32 percent (approximately 3 percent by dry weight).
This sludge is more concentrated than that in the secondary clarifiers
and should be pumped directly to the digester rather than to the clarifiers.
DIGP-1STER AND DRYING BEDS
The covered digester is used only as a holding basin prior to dis-
charging to the sludge drying beds.- Insufficient capacity and lack of
heating capability prohibit the use of the digesters for sludge condition-
ing. The digester (holding basin) does not satisfactorily thicken and
condition the sludge. Consequently, a thin sludge is discharged to thp
drying beds; 14 percent by centrifuge or approximately 1% by dry weight.
Sludge is held in the digester as long as possible, usually 4 to 5
weeks, before discharging to the drying beds. Insufficient bed capacity
necessitates sludge being discharged over drying sludge.
Digester supernatant is discharged directly to the //I clarifier and
places an additional strain on this treatment unit. The supernatant should
be pumped back to the aeration basin for treatment and to reduce the
impact on the clarifier.
EXAMINATION OF MICROSCOPIC ORGANISMS
Microscopic examinations of mixed liquor solids from the aeration
basin, return sludge from the clarifiers, return sludge from the chlorine
contact basin, and solids washed over the weir during bulking, all showed
a fairly heavy growth of filamentous bacteria and fungi. The solids
appeared light brown and fluffy, indicating a young or unstable activated
sludge. Dispersed throughout the solid particles were a few red, green
and yellow macrofibers.
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Microscopic life in the mixed liquor solids arid bulking solids con-
sisted of green algal cells, dinoflagellates, nematodes, larvae, sarcodina
and free swimming ciliates. The rotifer and stalked ciliate population
were in concentrations indicative of conditions rendering a good stable
effluent.
Return sludge from the chlorine contact basin showed no active
vsicro or macroscopic life forms. The protozoan organisms present
were encysted due to the toxic effect of the chlorine. The filamentous
bacteria cells showed little or no damage to the filament structure;
however, some active long slender rod shaped bacteria cells were present
within the liquid phase which could be attributed to filamentous breakdown.
Return sludge from the clarifier showed a light brown, fluffy sludge
of very thin consistency. Filamentous bacteriawere the predominant type
present. Protozoans were in large numbers and of many different types;
there were free swimming ciliates, flagellates, nematodes, stalked ciliates,
and amoebas. The consistency of the sludge did not allow the particles
to clump together and the edges showed no growth or growth characteristic,
which indicates a somewhat unstable sludge.
A measure of the activity of these organisms was observed using the
oxygen uptake analysis.
OXYGEN UPTAKE RATES
Sludge activity was determined utilizing the differences in oxygen
uptake rates of the sludge before and after introduction of the raw waste.
The ratio of these two variables or "load ratio" is calculated as
follows:
, j ., A DO/min of fed sludge
Load ratio = 7 5——
A DO/mm of unfed sludge
Table VI is a listing of the oxygen uptake rates and calculated load
ratios for each day of observation. The oxygen uptake procedure is
presented in Appendix C.
Oxygen uptake values for both fed and unfed analyses were low which
reflect the low solids content of the return sludge. The reverse can
be seen with the chlorinated sludge from the chlorine contact basin.
Solid content was high and the oxygen uptake value was high. This could
possibly be attributed to an initial chemical oxygen demand or septicity
of the chlorine contact chamber sludge. As shown in Table VI, the plant
was operating at a load range of 1.5 to 3.6. Normally extended aeration
plants operate best with a load factor of less than 2.
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TABLE VI
OXYGEN UPTAKE RATES
Date
Time
%RS
A.verage O-pUptake
ppm/min ppm/min
URSl/ FRSI/
Load Ratio
FRS/URS
9/23/75 1130
9/23/75 1530
9/23/75 1600
9/24/75 1030
9/24/75 1430
9/25/75 0900
9/25/75 1230
9/25/75 1230
50
50
50
47
45
46
43
43
0.26
0 .^21
0.-14
0.16
0.15
0.2
0.2
0.8
0.4
0.45
0.8
0.4
0.4
0.5
0.47
0.49
2.00
2.25
1.54
1.90
3.57 ,
o n,hf
1/ URS - Unfed Return Sludge using clarifier effluent
2/ FRS - Fed return sludge using raw influent
3/ Measurements determined using chlorine contact basin sludge
4J Oxygen uptake rate for return sludge in clarifier #1 only while
bulking
5/ Oxygen uptake rate for return sludge in clarifier //2 only while
bulking
LABORATORY
The general condition of the laboratory and laboratory equipment was
excellent. This can be attributed to a conscientious attitude of the
operators.
The BOD5 of the influent is variable, consequently more than one
dilution per sample should be made. This would help insure oxygen deple-
tion within the 40 to 70 percent range recommended by the procedure.
Distilled water used for making dilutions in the BOD5 test should
contain "Formula C" reagents as per "Standard Methods for the Examination
of Water and Wastewater", 13th Edition. These reagents make available
essential nutrients for the bacteria.
When analyzing a chlorinated sample for BOD, the plant personnel are
currently allowing the sample to sit for a period of time for dechlorination,
A more efficient and quicker method for aechlorinating a sample is listed
in Appendix D.
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Currently the plant personnel are not running the chemical oxygen
demand (COD) determination as a control test. This analysis would be a
helpful addition to routine analyses as it gives valuable information
when assessing organic loading on the plant. The COD test measures a
portion of the waste that may not be reflected hy the BOD5 analysis and
the data is obtained in a relatively short period of time (three to four
hours as compared to five days for BOD^).
Laboratory personnel expressed a desire for methods of nitrogen
analysis. Enclosed with this report is a copy of "Methods for Chemical
Analysis of Water and Wastes", 1974, published by the Environmental
Protection Agency. This manual contains methods for the analysis of
ammonia nitrogen, total Kjeldahl nitrogen, and nitrate-nitrite nitrogen.
-19-
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APPENDIX A
'CHEMICAL LABORATORY DATA
PEOPLES'CREEK STP
-------
APPENDIX A (Cont)
CHEMICAL LABORATORY DATA
PEOPLES CREI'.K STP
-------
APPENDIX A (Cont)
CHEMICAL LABORATORY DATA
PEOPLES CREEK STP
GAFFNEY. SC
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SAD j
# j STATION
MONTH I
DAY
YEAR
TIME
0179 | S-3 j 9
23
75
j i 1 j
1620 | 30 |23,23317,43^
1
1 1 '
1 ! 1
J i i
1 i
0196 S-3
9
24
75
1315 I 33
22, 66^6 . 90(] !
j |
1 i
j
i 1 1
t i
j J
I
i
i
1
0167 j RS j 9
23
75
0945
ii !
: i
! i
i 1
1 1
0176 j RS | 9
23
75 ! 1430
13
1
\
I
i
1
i
!
| 1
1 ! i
0182 ; RS | 9 {24
75
i
0830 |11.5!
i
!
; j
i i
i
i i 1 i
J ! ! :
0197 | RS
9 |24
75
I 1
1315 ! 12 !
I
[
i
i
_ III .
i
1
0204 : RS
9
i
25 175
i 1
0835 i 12 i
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j 1
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! 0171 [ D
9
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Mil
1 1
1 i i
-------
APPENDIX A (Cont)
CHEMICAL LABORATORY DATA
PEOPLES CREEK STP
GAFFNEY. 3C
1
0164 j
A-5
9
23
1
75 j 0910
i95
90
86
81
i
77
74
70
65
60
5.5
' i
1
3,140 ,2,400
0172 |
A-5
I 9
23
75
1430
*
i 95
!
«
89
84
80
76
70
65
60
46
Sat o\}ernig
not rise 30
it did
*
|
5.5 !3,040
2,320
;
;
0185 !
A-5
1 9
24
75
0830
| 98
91
87
83
79 ! 73
68
64
48
5.5.
! j
2,900 2,260 i
'
i
0190 :
A-5
1
! ^
24
75
1315
1
i 96
94
90
87
84
80
75
70
6S
4Q
I 5.0
3,040 12,340
0207 '
A-5
1
1 9
25
7 5
0847
i
i 97
94
90
85
80
77
70
64
60
47
i
i 5.0
1 1
3,060 |2,380 1
I
i ! ! 1 1 ! 1
i i i i ! i !
' 1
i
1
1
0165
S-l
9
23
75
0945
5
e
1
! !
i 1 1
! ! !
! 1
11
1
6,375 14,775
0174 :
S-l
9
23
75
i i
1430 | !
I
1
i i
i
17 lo, 225I7 ,750
0183 !
S-l
9
24
75
0830
5
r
1
1
u
¦
7,150 15,375
0194 !
S-l
9
24
75
1315
1
i
1
:
!
|
! 12
I
7,525 j5,700
1
!
0202 i
S-l
9
24
75
1
0835 |
i
!
i
1
1
! 11
6,450 j4,925 j
1
1
I
I __
i
1
!
|
0166 !
S-2
9
23
75
!
0945 |
" ""
j
11
6,875
5,200
0175 |
S-2
9
23
7.
1430
r
t
1 1
i
!
i
i
10
5,850 !4,450
0184 j
S-2
9 1
24
»
0830
!
12
6,975
5,375
0195 !
S-2
9
24
75
1 i
1315 ! j
t
12
7,650
I 1
5,775 | |
0203 |
S-2
9
25
»
0835
i
i
13
7', 675
5,900
^ L
Lo >
I
-------
Appendix B
GENERAL 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 E3, respectively,
were sampled for three 24-hour periods with ISCO model 1392-X automatic
samplers. Aliquots of sample were pumped at hourly intervals into indi-
vidual refrigerated glass bottles which were composited proportional to
flow at the end of each sampling period.
Dissolved oxygen was determined at all stations using a YSI model
51A dissolved oxygen meter.
Sludge activity was determined by the oxygen uptake procedure
presented in Appendix C. The rate of oxygen uptake for fed and unfed
sludge was determined and a load factor was calculated. The load factor
reflects the conditions at the beginning and end of aeration and is
helpful in assessing sludge activity and plant operation.
A series of standard operational control tests were run twice
daily; once in the morning and once in the afternoon for three days.
The control tests consisted of:
e sludge settleability as determined by the scttloineter test;
e percent solids by centrifuge determined on the mixed liquor
and return sludge;
o TSS and VSS analysis on aerator, and return sludge;
© depth of clarifier sludge blanket;
o turbidity of the effluent from both final clarifiers.
Physical observations of individual unit processes and flow meter
readings were recorded daily.
-24-
-------
APPENDIX C
OXYGEN UPTAKE PROCEDURE3
A. Apparatus
1. Electronic DO analyzer and bottle probe
2. Magnetic stirrer
3. Standard BOD bottles (3 or more)
4. Three wide 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
B. Procedure
1. Collect samples of return sludge, aerator influent and final
clarifier overflow. Aerate the return sludge sample promptly
2. Mix the return sludge and measure that quantity for addition
to a 300 ml BOD bottle that "corresponds to the return sludge
proportion of the plant aerator, i.e. fo,r a &0% return sludge
percentage in the plant the amount added to the test BOD
bottle is:
300 X .4 = 120 = 86 nil.
1.0 + .4 1.4
3. Carefully add final clarifier overflow to fill 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 BOD bottle with the
BOD bottle adapter. Invert the combination and shake vigorously
while transferring the contents. Re-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 (ADO/mln). Check the final sample temperature.
This approximates sludge activity in terms of oxygen use
after stabilisation of the sludge during aeration (unfed
sludge activity).
-25-
-------
APPEND[X C (Cont)
7. Repeat steps 2 through 6 on a replicate sample of return
sli;Jge that has been di]uLed with aerator influent (fed
mixture) racher 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 effect 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
factor means abundant, acceptable feed under favorable conditions. A
snail LF means dilute 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, NER.C, Cincinnati.
-26-
-------
APrENDIX D
DECHLORINATING PROCEDURE
Samples for BODc; determinations can be dechlorinated by the addition
of Sodium Thiosulfate solution. All reagents are the same as in the
Winkler dissolved oxygen test.
1. To 200 mis of sample, suspected to contain chlorine, add
approximately 1 gram of Potassium Iodide (KI) crystals and swirl
to dissolve.
2. Add 1.0 mis of concentrated sulfuric acid and mix thoroughly.
3. Add approx. 1 ml of starch indicator. If a blue color is present
upon the addition of the starch then chlorine is present in the
sample.
4. Titrate the blue mixture with sodium thiosulfate solution. The
endpoint is reached when the blue color dissipates. Record the
volume of thiosulfate solution used. This volume is the amount
of thiosulfate solution necessary to dechlorinate 200 mis of
sample. Do not use this portion for analysis.
5. Take an additional volume of sample and add only the thiosulfate
solution prope1"tion?.J. to the amount found necessary to dechlorinate
the 200 mis. Example. if 2 mis of the thiosulfate were required
for the 200 ml sample, then 400 mis of sample would require k mis
of thiosulfate solution; 800 mis would take 8 mis; 1000 mis would
take 10 mis, etc.
If is suggested that 500 to 1000 mis of sample be dechlorinated.
-27-
------- |