Environmental Protection Technology Series
Evaluation Of The Bio-Disc Treatment
Process For Summer Camp Application
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH- REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
U. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY . series. This series
describes research performed to develop and
demonstrate instrumentation/ equipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
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EPA-670/2-73-022
August 1973
EVALUATION OF THE BIO-DISC TREATMENT PROCESS
FOR SUMMER CAMP APPLICATION
by
William A. Sack
Stephen A» Phillips
West Virginia University
Morgantown, West Virginia 26506
Project #3-800707
Program Element 1B2043
Project Officer
Dr. Robert L» Bunch
UoS. Environmental Protection Agency
National Environmental Research Center
Cincinnati, Ohio 45268
Prepared For
OFFICE OF RESEARCH AND DEVELOPMENT"
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
For sale by the Superintendent ot Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.05
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EPA Review Notice
This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the Environ-
mental Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
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ABSTRACT
The bio-disc wastewater treatment process was evaluated during
operation for one summer at a recreational camp. The bio-disc section
consisted of four stages, each of 22 polystyrene discs 1.98 m (6.5 ft)
in diameter, and was preceeded by a septic tank that served to handle
both the primary and the biological sludge produced.
Evaluation of the plant included time required for start-up,
organic removal efficiency, response to flow variations, nutrient
removals, aesthetic impact, and required maintenance and operation
attention.
Overall organic removals reached essentially full efficiency by the
end of the first week of operation. However, removals across the
bio-disc section continued to increase somewhat till about the fifth
or sixth week of operation. Average bio-disc unit percent removals were
BOD - 84.5, COD - 71, TOG - 71, and suspended solids - 75. Average
overall plant percent removals were 87.5, 79, 75, and 97.5 respectively.
Total nitrogen removal through the plant averaged 40.3 percent.
Ammonia nitrogen removal in the disc section was only 25.2 percent.
Overall total phosphorus removal was 15 percent. Maintenance and
operational requirements for the plant were minimal requiring an average
of 1.3 hours per week during the summer.
This report was submitted in fulfillment of Project #5-800707,
under the sponsorship of the Environmental Protection Agency by the
West Virginia State University.
iii
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CONTENTS
Section
I
II
III
IV
V
VI
VII
VIII
IX
X
CONCLUSIONS
RECOMMENDATIONS
INTRODUCTION
LITERATURE REVIEW
DESCRIPTION OF THE BIO-DISC PLANT AND PROCEDURES
RESULTS AND DISCUSSION
WASTEWATER CHARACTERISTICS AND FLOW
START-UP AND OVERALL PLANT PERFORMANCE
BIO-DISC UNIT PERFORMANCE
REMOVAL OF NITROGEN AND PHOSPHORUS
TOTAL COLIFORM REMOVAL
SLUDGE ACCUMULATION
MAINTENANCE AND OPERATOR ATTENTION
AESTHETICS
ACKNOWLEDGMENTS
REFERENCES
GLOSSARY
APPENDICES
A. FLOW MEASUREMENTS
B. SUPPLEMENTAL DATA AND FIGURES
C. DISCUSSION OF CHLORINATED VALUES
Page
1
3
5
7
9
17
17
22
31
39
39
41
41
41
43
45
47
49
50
51
76
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FIGURES
No. Page
1 Schematic Diagram Camp Horseshoe Bio-Disc Plant 10
2 Bio-Disc Section Before Installation 11
3 Front End of Plant 12
4 Plant Exterior 12
5 Daily Sewage Flow 19
6 Daily Flow Pattern 20
7 Typical Hourly Flow Pattern Using Sample Day of
June 27, 1972 21
8 Daily Overall BOD Removal Efficiencies 24
9 Daily Overall COD Removal Efficiencies 25
10 Daily Overall Suspended Solids Removal Efficiencies 26
11 Comparison of Wastewater Characteristics During Two
Time Segments of Study 28
12 Comparison of Suspended Solids Values During Two
Time Segments of Study 29
13 Average Weekly Bio-Disc Unit Removal Efficiencies 32
14 Effect of Hydraulic Loading on Bio-Disc Unit BOD
Removal Efficiency 34
15 Effect of Hydraulic Loading on Bio-Disc Unit COD
Removal Efficiency 35
16 Effect of Staging on TOG Removal 37
17 Mixed Liquor Average Dissolved Oxygen Content Across
Bio-Disc Stages 38
18 Average Ammonia Reduction and Nitrification Occurring
Across Bio-Disc Unit 40
19 Comparison of Raw BOD Values Before and After First
Five Weeks of Plant Operation 64
VI
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FIGURES
(continued)
No. Page
20 Comparison of Settled BOD Values Before and After
First Five Weeks of Operation 65
21 Comparison of Effluent BOD Values Before and After
First Five Weeks of Operation 66
22 Comparison of Raw COD Values Before and After
First Six Weeks of Operation 67
23 Comparison of Settled COD Values Before and After
First Six Weeks of Operation 68
24 Comparison of Effluent COD Values Before and After
First Six Weeks of Operation 69
25 Comparison of Raw TOG Values Before and After
First Six Weeks of Operation 70
26 Comparison of Settled TOG Values Before and After
First Six Weeks of Operation 71
27 Comparison of Effluent TOG Values Before and After
First Six Weeks of Operation 72
28 Comparison of Raw Suspended Solids Values Before and
After First Six Weeks of Operation 73
29 Comparison of Settled Suspended Solids Values Before
and After First Six Weeks of Operation 74
30 Comparison of Effluent Suspended Solids Values Before
and After First Six Weeks of Operation 75
V1L
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TABLES
No. Page
1 Plant Specifications 13
2 Analyses Performed and Frequency of Analysis - 14
3 Average Wastewater Characteristics 18
4 Relation of Daily Flow Pattern to Total Flow and
Camp Activity 22
5 Comparison of Removal Efficiencies for Two Time
Periods 30
6 Daily Wastewater Characteristics 51
7 Daily Sewage Flows - 1972 62
8 Comparison of Wastewater Characteristics for Time
Periods 6/18/72 to 7/22/72 and 7/23/72 to 8/24/72 63
V11L
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SECTION I
CONCLUSIONS
1. The bio-disc wastewater treatment process (also known as the Rotating
Biological Contactor) appeared to be relatively well suited to a
summer camp application where sewage flow was low and fluctuated
considerably.
2. Start-up of this plant required a minimum amount of time. Only one
week was needed to provide adequate treatment.
3. Average bio-disc unit percent removals were BOD - 84.5, COD - 71,
TOG - 71, and suspended solids - 75. Average overall plant percent
removals were 87.5, 79, 75, and 97.5 respectively.
4. Because of the low flows encountered, the performance of the plant
was not greatly affected by either organic or hydraulic loading.
5. The effluent from the septic tank was stronger during the second half
of the summer due to incomplete anaerobic decomposition of the settled
solids. This resulted in somewhat poorer and more erratic removals
during this period.
6. Overall total nitrogen removal averaged 40.3 percent. Ammonia
nitrogen through the disc section fell from 41.3 to 30.9 mg/1 giving
25.2 percent removal. The low nitrification was probably due to the
relatively high BOD in the plant effluent of 32 mg/1. Phosphorus
removal through the plant averaged 15 percent.
7. Sludge handling problems were minimal with this plant during its three
months of operation. An annual cleaning of accumulated sludge by a
tank truck is more than adequate.
8. Maintenance requirements for this plant were quite small. This study
revealed that only 14 hours of maintenance were required during
nearly 11 weeks of continuous operation, or 1.3 hours per week.
9. The plant did not produce objectionable odors nor detract from the
natural environment of the camp.
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SECTION II
RECOMMENDATIONS
In order to make efficient use of the organic removal capacity of
the bio-disc stages, pretreatment of raw waste should be as efficient as
possible. Although use of a septic tank is well suited to a "package
plant" application, it should be capable of better organic removals than
found in this study. It is recommended that well digested sludge from a
properly functioning digester be pumped into the septic tank at the start
of each season to encourage good digestion from the outset and allow
efficient operation of the septic tank and bio-disc.
Recycle of sewage from the final clarifier during periods of low
flow should be made an automatic function in order to keep the bio-mass
in an optimum condition. At Camp Horseshoe, low flow usually occurred
on weekends when the operator was away from the camp and therefore no
recirculation was carried out.
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SECTION III
INTRODUCTION
Treatment of wastewater flows from summer recreational camps
presents a difficult problem. The volume of such flows fluctuates
considerably depending upon the activity and number of campers throughout
the summer. Other difficulties facing designers in providing wastewater
treatment processes for such an application include a frequent lack of
trained operators, preservation of the aesthetic qualities associated
with these areas, and seasonal operation.
This study was performed in order to evaluate the effectiveness of
the rotating biological disc wastewater treatment process in treating
wastes from a summer camp. The evaluation consisted of monitoring
start-up, determination of removal efficiency, microscopic observations,
recording of required maintenance, and evaluation of aesthetic accept-
ability. The bio-disc process (also called Rotating Biological Contactor
or RBC) is a secondary biological treatment scheme which utilizes a
fixed microbial slime to metabolize wastewater organics. The slime is
attached to a series of circular discs which remain approximately
one-half submerged while rotating through the wastewater. As the discs
rotate, the wastewater trickles down the face of the discs, providing
the required reaction time for aeration and metabolism of the waste.
The rotation of the discs serves to keep sloughed biological solids
and solids carried over from primary treatment in suspension until they
can be separated in a final clarifier.
The bio-disc unit studied is located at Camp Horseshoe, in Tucker
County, West Virginia. The camp is owned by the U. S. Forest Service
and rented to the Y.M.C.A. It is utilized by many different groups
with most of the campers being of school age.
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SECTION IV
LITERATURE REVIEW
Though relatively new in this country, the bio-disc process has
already been used in a number of applications. Synthetic sewage con-
sisting of dairy solids, dipotassium orthophosphate, and diammonium
orthophosphate was treated by a bio-disc unit consisting of two stages
of one hundred 0.91 m (3 ft) diameter aluminum discs per stage (1).
The two stages were separated by an intermediate settler and followed
by a final clarifier. COB removals of up to 80 percent were obtained,
depending upon hydraulic loading, organic loading, disc rpm, mixed
liquor D.O., and temperature.
Birks and Hynek (2) reported on a bio-disc system used to treat
cheese processing wastes. The system consisted of a septic pre-treat-
ment and flow equalization unit, followed by a four stage bio-disc unit
with an integral clarifier. There were twenty-two 3.05 m (10 ft)
diameter molded polystyrene discs per stage. At flows of 11.37 to 18.96
cu m/day (3000 to 5000 gpd) and a COD influent of up to 3000 mg/1, 85 to
86 percent COD reduction was obtained by the unit. For BOD influents
ranging from 705 mg/1 to 1700 mg/1, removals of 95 percent or better were
achieved.
Application of the bio-disc treatment system to treatment of
municipal wastewater was studied for a year utilizing a unit consisting
of ninety-one 1.75 m (5.74 ft) diameter discs made of expanded polystyrene
beads (3). The disc section was divided into two stages and received
primary treated wastewater from a small municipal plant. The unit also
included a final clarifier. At a hydraulic loading of 61 cu m/day/lO^ sq
m (1.5 gpd/ft^) of disc area and 3.2 to 5 rpm, BOD removals of 90 percent
were attained. Under these same conditions, suspended solids removal
was 80 percent while COD removal efficiency ranged from 80 to 85 percent.
Another significant accomplishment of this unit was high ammonia and
Kjeldahl nitrogen removal, which ranged from 85 to 95 percent. High
nitrification rates were noted. Three stages of fifty 1.22 m (4 ft)
diameter plastic discs were used in conjunction with a final clarifier in
a study by Borchardt (4) treating municipal waste. During three years of
operation, BOD removals of 89 to 94 percent were consistently achieved.
The effects of various operational parameters on the bio-disc process
were studied by several workers (1,3,5). These parameters included
hydraulic loading, rotational disc speed, sludge recycle, temperature,
and staging. The conclusions reached were that organic removal efficiencies
increased with increased disc rpm, staging and temperature. It was also
found that organic removal efficiencies increased with decreased hydraulic •
loading and that sludge recycle had very little effect on the process.
These three studies also identified organisms present in the disc biomass.
The organisms found included Geotrichum candid urn and Bacillus cereus,
which because of their filamentous nature, functioned as support media;
-------
Zoogloea fillpendula, Pseudomonas denitrifleans, Aerobacter aerogenes,
Escherichia coli, and Sphaerotilus. A progression of fauna through
successive stages of the bio-disc system was also noted (5). The fauna
consisted of free swimming and stalked protozoa, rotifers, and nematodes.
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SECTION V
DESCRIPTION OF THE BIO-DISC PLANT AND PROCEDURES
The treatment plant at Camp Horseshoe is shown schematically in
Figure 1. The "package" bio-disc section and clarifier before installa-
tion are shown in Figure 2 with the clarifier and chlorine contact chamber
at the far left. Figure 3 shows the front end of the plant as installed
in the building and Figure 4 is a view of the building itself. Waste
enters the plant by gravity into a below-ground rectangular septic tank
which has a capacity of 33.73 cu m (8900 gallons). The clarified waste
then overflows into a 14.02 cu m (3700 gallon) buffer tank. Two
0.152 cu m/min (40 gpm) float-controlled pumps raise the waste from the
buffer tank to the bio-disc section of the plant which is located directly
above the septic and buffer tanks. From the buffer tank, the waste is
first pumped into a feed tank at the head end of the bio-disc unit. An
overflow line is provided to permit flows in excess of design flow to
return from the feed tank to the buffer tank. Four bucket feeders
attached to the main shaft of the disc section collect the waste from the
feed tank and feed it to the first bio-disc stage. The bucket feeders
are not shown in Figure 1 for sake of clarity but may be seen in Figures
2 and 3. When the feed tank is full or overflowing, the buckets feeders
supply a constant maximum rate of sewage to the discs of 33.73 cu m per
day (8900 gpd).
The bio-disc unit which was designed to rotate at 2 rpm, has four
stages in series with each stage separated by a bulkhead. Each stage
contains 22 molded polystyrene discs 1.98 m (6.5 ft) in diameter, 1.27
cm (0.5 inches) thick, and spaced on 2.54 cm (1.0 inch) centers. Waste
flows from stage to stage through openings in the bulkheads and then into
a final clarifier. Recycle of clarified effluent from the final clarifier
to the septic tank is possible through a valved gravity overflow line.
Sludge which has settled out is removed by a rotating scraper with hollow
connecting arms through which the sludge flows by gravity to the septic
tank. Effluent normally passes from the final clarifier to a chlorine
contact chamber for disinfection, and then is discharged from the plant.
As mentioned above, the volume of the septic tank is 33.73 cu m
(8900 gallons) and that of a buffer tank is 14.02 cu m (3700 gallons).
These volumes were based on a design flow of 33.73 cu in/day (8900 gpd) to
provide a detention time of one day in the septic tankr However, it will
be shown later that the design flow was not achieved during this project
and therefore detention times exceeded normal ranges. Table 1 summarizes
plant design specifications.
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Disc section
Feed tank
Overflow
line
ft
Chlorine
contact
chamber
Final clarifier
/
Outlet
Recycle
line
Pumps
%
o o
Buffer tank
Septic tank
w
Inlet
Figure 1. Schematic Diagram Camp Horseshoe Bio-Disc Plant
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Figure 2. Bio-Disc Section Before Installation
11
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Figure 3. Front End of Plant
Figure 4. Plant Exterior
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TABLE 1
Plant Specifications
1. Septic Tank Volume - 33.73 cu m (8900 gallons)
2. Buffer Tank Volume - 14.02 cu m (3700 gallons)
3. Feed Tank Volume - 0.61 cu m ( 160 gallons)
4. Disc Section Volume, Gross - 4.93 cu m (1300 gallons)
5. Disc Section Volume, Net* - 2.16 cu m ( 570 gallons)
6. Submerged Volume of Discs - 2.77 cu m ( 730 gallons)
7. Total Effective Disc Area - 539.80 sq m (5800 ft2)
8. Final Clarifier Volume - 4.62 cu m (1220 gallons)
9. Final Clarifier Surface Area - 5.40 sq m ( 58 ft2)
10. Disc Velocity - 2 rpm
11. Disc Diameter - 1.98 m (6.5 feet)
12. Number of Stages - 4
13. Number of Discs per Stage - 22
*As measured with no biomass growth
The entire above-ground portion of the plant is enclosed by a
garage-like structure with an exterior which conforms to the other
buildings in the camp. The structure provides weather protection for the
unit and its associated controls as well as helping maintain the aesthetic
appearance of the area. As may be noted from the above description, the
facility is truly a "package plant". All unit operations are performed
by the septic tank, buffer tank, and bio-disc unit itself. While the
bio-disc section provides secondary biological treatment and final clari-
fication, the septic and buffer tanks provide primary sedimentation,
concentration and digestion of raw and biological sludge, solids, storage,
flow equalization, and mixture and seeding of the raw waste with the
recycled bio-disc sludge.
The sewerage system at the camp serves two toilet and shower build-
ings, the camp kitchen, and the camp infirmary. There are also three
outdoor privies which receive considerable usage and thus reduce the
waste load on the plant. The sewer line from the camp area to the plant
is 366 m (1200 feet). This relatively short run prevented significant
breakup of the sewage solids while flowing to the plant.
Except for a few instances, samples were collected daily throughout
the 1972 camping season which ran from June 11 to August 25, or for a
total of 11 weeks. Sampling points were as follows:
1. Raw Sewage
2. Settled Sewage
3. Effluent
4. Chlorinated Effluent
Manhole directly above plant
15.3 m (50 feet) plant
Buffer Tank
Final Clarifier
Chlorine Contact Chamber
13
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Samples were collected four times daily for compositing at 8:00 A.M.,
1:00 P.M., 6:00 P.M., and 10:00 P.M. Grab samples were collected as
required for coliform analysis, pH, D.O., and determination of TOG
removals across the stages. All samples were manually collected except
during the initial week when raw sewage was collected using an automatic
sampling device. This procedure was abandoned when it was realized that
the sewage was not mascerated well enough for the sampler to function
without frequent blockage. It was also found that the sampler did not
always lift a representive sample of the entrapped solids to the storage
bottle.
The collected samples were stored in an on-site refrigerator. Every
other day these samples were composited with respect to flow, placed in
an ice chest, and returned to the laboratory for analysis. Transit time
to the laboratory was 90 minutes. The analyses performed and frequency of
analysis are shown in Table 2. The analyses were performed in a staggered
manner with respect to days of the week.
TABLE 2
Analyses Performed and Frequency of Analysis
Frequency
Analysis
Raw
Settled
Effluent
Chlorinated
Effluent
BOD-5
COD
TOG
Suspended Solids
Total Solids
P04-P
N02-N
N03-N
NH3-N
TKN
Total Coliform
Temperature
Dissolved Oxygen
PH
Microscopic
Observations
Flow
*2/W
* D
*4/W
4/W
* W
w
w
w
w
w
4/W
2/W
2/W
2/W
D
4/W
4/W
W
W
W
W
W
W
2/W
2/W
2/W
D
4/W
4/W
W
W
W
w
w
w
w
4/W
2/W
2/W
Bi-weekly on all stages
Recorded continuously
* D Daily
»• W - Weekly
* 2/W - Two samples per week
* 4/W - Four samples per week
2/W
D
3/W
14
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The nature of several of the analyses required that they be performed
on site. These included total coliform, temperature, dissolved oxygen,
pH, microscopic observation of biomass, and flow. All other analyses
were performed in the laboratory. Procedures utilized were in accordance
with "Standard Methods for the Examination of Water and Wastewater",
Thirteenth Edition, 1971 as shown below.
ANALYSIS
BOD-5
COD
TOG
Suspended Solids
Total Solids
P04-P
N02-N
N03-N
organic-N
NH3-N
TKN
Total Goliform
Dissolved Oxygen
METHOD
Method 219 using the azide modification for
the dissolved oxygen measurement
Method 220 - Standard dichromate reflux method
Method 138A - Tentative combustion - infrared
method
Method 224C using Gooch crucibles and glass-
fiber filter discs
Method 224A
Digestion by Method 223C-III, Ib, and
phosphorus determination by Method 223E,
stannous chloride reagent
Method 134
Method 213C
Method 135-4b
Method 135-4b with titration of ammonia in
the distillate
Found by addition of organic-N and NH^-N
values
Method 408A using the single step direct
technique with M-Endo liquid medium
Method 218F
Method 221
Daily flow was determined by a mass balance around the buffer tank.
The specific procedure used is described in Appendix A.
15
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SECTION VI
RESULTS AND DISCUSSION
The treatment facility was constructed and put into operation mid-
way through the 1971 camping season. Hence this study, which was made
during the 1972 season, covers the first full summer of plant operation.
WASTEWATER CHARACTERISTICS AND FLOW
Average wastewater characteristics are presented in Table 3. It
may be seen that the waste stream encountered, with a raw BOD of 250 mg/1
and COD of 563 mg/1, was somewhat stronger than normal municipal wastes.
The plant sewerage system serves only rest rooms, showers, and the camp
kitchen as previously noted. This, in effect, makes it a separate
sanitary sewer system. Also, the camper's activities included frequent
use of paints and dyes which added to the waste strength. Extensive use
of organic cleansing agents by staff personnel also caused an increase
in overall waste strength. Finally, it appeared that very little ground
water infiltration entered the plant system except during very heavy rains.
Flow measurements were not obtained until the first of July, about
three weeks after the camp went into operation, since flow measuring
equipment was not available until that time. Figure 5 shows that the flow
of sewage to the treatment plant ranged from zero to 23.95 cu m/day (6320
gpd). Daily flow values are presented in Table 7 of Appendix B. The
average flow throughout the summer (less weekends) was 16.88 cu m/day
(4455 gpd). The average flow including weekends when no campers were
present was 14.63 cu m/day (3860 gpd). These values were considerably
below the design capacity of 33.73 cu in/day (8900 gpd). The minimum
flows normally occurred on Friday, Saturday, or Sunday, depending upon
when the previous week's campers had left. During the weekend of June
15 to 17, three commodes ran continuously, accounting for the absence of
the normal minimum.
Figure 6 illustrates the average daily flow pattern. The time
increments shown are those used in the sampling schedule. Table 4
relates the average flow of each time period to average daily flow and
camp activity. Figure 7 shows a typical hourly flow pattern.
During the summer, the number of people in camp varied from 95 to
221 with an average of 143. The average per capita flow of sewage when
campers were present was 0.12 cu m/cap/day (31 gpcd), with a range of
0.09 to 0.15 cu m/cap/day (25 to 39 gpcd). These flow rates were depend-
ent upon the nature and size of the particular group utilizing the camp
and, of course, do not reflect use of the privies. The average per capita
flow for the entire period (weekends included was 0.10 cu m/cap/day
(27 gpcd). Although waste strength was high, low flows offset this to
result in only 27.2 gms (0.06 Ibs) BOD per capita per day being produced.
17
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TABLE 3
Average Wastewater Characteristics
Raw
Settled
Effluent
Chlorinated
Effluent
BOD-5 (mg/1)
COD (rag/1)
TOG (mg/1)
Suspended
Solids (mg/1)
Total Solids
(mg/1)
P04-P (mg/1)
N02-N (mg/1)
N03-N (mg/1)
NH3-N (mg/1)
TKN (mg/1)
Total-N (mg/1)
Total Coliform
(per 100 ml)
Temperature (°F)
PH
Dissolved
Oxygen (mg/1)
Flow (cu m/day)
250
563
119
315
11.3
T
0.24
39.0
72.5
75.8
495 x 106
66.9
6.9
1.5
Daily Average
Daily Average
210
415
103
31
9.2
0.04
0.37
41.3
57.0
57.4
206 x
32
120
30
8
355
9.6
.96
,67
106
6.8
30.9
35.6
45.2
49 x 106
67.5
7.0
* 50
* 172
0.8
2.2 1.8
16.88 (4455 gpd) excluding weekends
14.63 (3860 gpd) including weekends
Daily values for the above parameters are contained in Tables 6 and 7
of Appendix B.
*See Appendix C for discussion of these values.
18
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30
rt
•a
CO
g
n)
60
ro
O
NOTE: Dashed lines indicate
weekend periods
n
20
3
O
10
8/24
Calendar Date (1972)
Figure 5. Daily Sewage Flow
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NJ
o
t-i
3
O
M
0)
CU
3
O
"•^^
g
r-t
0)
60
cfl
>-l
0)
1.50 -
1.25 _
1.00 -
0.75 -
0.50 -
0.25 -
8 A.M.-l P.M. 1 P.M.-6 P.M. 6 P.M.-10 P.M.
Time Periods
10 P.M.-8 A.M.
Figure 6. Daily Flow Pattern
-------
2.00
'i'
3 1.50
o
0
£ 1.00
0)
60
ctl
n sn
"h
i
i i
1
8 10 12 2
A.M.
4 6 8 10 12
P.M.
TIME
246
A.M.
Figure 7. Typical Hourly Flow Pattern Using Sample Day of June 27, 1972
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TABLE 4
Relation of Daily Flow Pattern to Total Flow and Camp Activity
Average Percent Normal Camp
Time-Period . Flow , of Average Activity
cu m/hr Dally Flow
8 A.M. - 1 P.M. 0.69 24 Morning cleanup
Breakfast
Lunch
1 P.M. - 6 P.M. 0.85 29 Dinner
Some showers
6 P.M. - 10 P.M. 0.65 17 Majority of
showers
10 P.M. - 8 A.M. 0.43 30 Minimum Activity
Note: 1 cu m/hr = 264.1 gph
Solids production was 36.3 gms (0.08 Ibs.) SS per capita per day.
These values were calculated for periods when campers were present.
Other workers have reported daily flows at similar camps with central
bath and toilet facilities and no privies to be 0.15 to 0.19 cu m/cap/day
(40 to 50 gpcd). The Camp Horseshoe per capita flow is comparable to
this range considering that flow from the privies was not measured.
Rainfall data for the Camp Horseshoe area was obtained from the U. S.
Forest Service at Elkins, West Virginia, and analyzed for correlation to
flow and sewage strength. No apparent correlation existed. Heavy rains
caused by Hurricane Agnes in June caused a hydraulic overload on the plant.
Because flow measuring equipment was not yet installed, actual flow was
not measured, but the septic and buffer tanks were surcharged for a period
of about one day. The bio-disc unit itself was not overloaded because of
its fixed feed rate. General flooding conditions and high water flowing
in a culvert between the camp area and the plant made it impossible to
collect samples during these periods of heavy rain. Therefore no data
was available to determine the effect of the rain on plant performance at
the time. No washout of the biomass occurred and samples collected after
the rains subsided did not reflect any dilution effects.
START-UP AND OVERALL PLANT PERFORMANCE
On June llth, the first regular group of campers arrived and the
plant began to discharge an effluent. This date was taken as plant start-
up since it marked the beginning of plant operation under continuous-flow
conditions. However the plant received its first sewage of the season
on May 26 with the arrival of 100 weekend campers. Two weeks later on
June 9, approximately 7.58 cu m (2000 gallons) of sewage and sludge from
a nearby National Forest Recreation Area were discharged into the camp's
22
-------
sewer system. The waste thus received during this pre-start-up period,
was continuously recirculated through the plant to begin seeding the
discs.
By the end of the second week of operation (June 25th), biological
growth had reached a thickness of 0.32 cm (1/8 inch) in some areas at the
front of the first stage and 0.16 cm (1/16 inch) at the rear of this
stage. The subsequent stages developed only a very thin coating of
growth during this time.
Organic removals during the first week were quite erratic as may be
noted in Appendix B, Table 6. During the early part of the week, the
settled BCD, COD and SS concentrations were higher than the raw. In
addition the effluent values during this period suggested negative removals
through the plant. These unusual values resulted, in part, from problems
with an automatic sampler on the raw stream as discussed in Section V.
The high effluent concentrations are thought to be primarily due to a tank
load of sewage and sludge which was slug-discharged in the plant on June
9 as noted above. As a result of these problems, the data from the first
week was not used in calculating the averages in Table 3 nor in plotting
subsequent curves.
Figures 8, 9, and 10 show overall plant removals of BOD, COD, and SS
for the entire summer season. It may be seen that after one week of
operation the percent removals of these parameters had reached 91.7,
98.5 and 92.5 respectively. The average values during the summer of BOD,
COD, and SS were 87.5, 79.0, and 97.5 percent. Thus, overall plant
removal had reached essentially average efficiency after the first full
week of continuous operation. It will be shown later however, that
removals across the disc section continued to increase up to about the
fifth or sixth week.
Inspection of Figures 8 and 9 shows that while overall BOD and COD
removals were reasonably stable during the first five to six weeks of
operation, they became erratic during the final weeks of the project.
It will be shown below that the operation of the septic tank was primarily
responsible for these erratic removal efficiencies during the latter part
of the summer. It is interesting to note from Figure 10 that SS removals
were quite consistent after about the third week of operation, remaining
well above 95 percent for the balance of the summer. Daily values of BOD,
COD, TOG, and SS are plotted in Appendix B, Figures 19 through 30 for
reference.
Influence of Septic Tank Operation on Plant Performance
The septic tank had been pumped out after the first summer's
operation and hence contained very little sludge during the initial weeks
of operation. As a result, the upper portion of the tank remained aerobic
(See*Appendix B, Table 6) and very little gas production occurred in the
early weeks. About the sixth week of plant operation, the majority of the
tank was anaerobic as indicated by the black color of the waste, a small
23
-------
100
C
V
o
M
0)
(X
o
C
0)
•H
o
•r-l
4-1
4-1
W
O
B
0)
cfl
M
0)
80
60
40
First five weeks
6/18
(1)
6/25
(2)
7/2
(3)
7/9
(4)
7/16
(5)
7/23
(6)
7/30
(7)
8/6
(8)
8/13
(9)
8/20
(10)
8/24
(ID
Calendar Date (1972)
(Week No.)
Figure 8. Daily Overall BOD Removal Efficiencies
-------
ro
Ol
0)
o
1-1
<0
ex
o
c
-------
4-1
C
0)
o
o
c
0)
•r-l
u
• r-l
w
cd
o
6
(U
Pi
100
80-
60
I
6/18
(1)
6/25
(2)
7/2
(3)
F9
(4)
7/16
(5)
7/23
(6)
7/30
(7)
8/6
(8)
8713
(9)
8/208/24
(10) (11)
Calendar Date (1972)
(Week No.)
Figure 10. Daily Overall Suspended Solids Removal Efficiencies
-------
amount of bubbling at the surface, and only traces of dissolved oxygen
in the septic tank and its effluent. However, the bubbling observed was
much less vigorous than that normally observed in a well operating
digester. Another indication of increasing anaerobic activity in the
septic tank was pH. During the first five weeks of operation, "average
weekly pH values increased slightly or remained the same, as the raw
waste passed through the septic tank. However, from the sixth to the
tenth week, "average" weekly pH fell from 0.1 to 0.5 of a unit, or
remained the same.
To gain further insight into the effect of septic tank operation on
plant efficiency a comparison was made of waste strength through the
plant for weeks 1 through 5 (June 18 to July 22) and 6 through 11 (July
23 to August 24). The data are tabulated in Appendix B, Table 8, and
plotted in Figures 11 and 12. Figure 11 reveals that the average values
of the septic tank (settled) BOD, COD, and TOG were considerably higher
during the second time period than the first. For example, settled COD
increased from an average of 249 mg/1 in the first time frame to 559 mg/1
in the second period. This was also true of the effluent values although
to a lesser extent. It may be seen that the average effluent COD
increased from 93 to 144 mg/1 from the first to the second period. Exam-
ination of Figure 11 also shows that while the raw organic strength also
increased during the second time frame, the increase was not of sufficient
magnitude to account for the large increase in the septic tank values.
Figure 12 shows that the SS values, in opposition to the above mentioned
trends, were actually lower during the second time period than the first.
The percent removal values for the septic tank and overall plant for the
two time periods, and the entire summer are presented in Table 5. The
Table further points out the dramatic change in septic tank efficiency
over the two periods and the resultant influence on overall removal. For
example, COD removal in the septic tank decreased from 49.6 to 9.1 percent
from the first to the second period. The influence on overall removal,
which decreased respectively from 91.2 to 76.5 percent was smaller, but
certainly of consequence. It should be noted that the overall organic
removals are somewhat below those reported in other bio-disc studies
(3,5,6,7). When considering septic tank operation, it must be kept in
mind that it also received excess biological solids which sloughed off of
the bio-discs. Since the film on the discs was still in the process of
forming during the early weeks, very little would have been sent to the
septic tank until the last five weeks. This undoubtedly contributed to
the higher organic strength of the waste leaving the septic -tank during the
latter portion of the study.
The high SS removal in the septic tank (90 percent) was due to two
main factors. These factors were long the detention times resulting from
the low flow (two days at average flow), and lack of vigorous bubbling
which normally occurs in anaerobic units.
27
-------
00
e
Q
O
60
6
450
300
150 _
750
500
250
150
100
50
I
I
JK1
Raw Settled Effluent
BOD Comparison
Raw Settled Effluent
COD Comparison
S
6/18/72
to
7/15/72
7/16/72
to
8/24/72
6/18/72
to
7/22/72
7/23/72
to
8/24/72
6/18/72
7/22/72
7/23/72
Raw Settled Effluent
TOG Comparison
Figure 11. Comparison of Wastewater Characteristics
During Two Time Segments of Study
28
-------
400-
300
6
•s^X
CO
O
tn
CU
CO
d
tn
200
100
6/18/72
7/22/72
7/23/72
8/24/72
Raw
Settled
Effluent
Figure 12. Comparison of Suspended Solids Values
During Two Time Segments of Study
29
-------
TABLE 5
Comparison of Removal Efficiencies for Two Time Periods
Septic Tank Removal Overall Removal
Average
6/18-7/22 7/23-8/24 During
Summer
Average
6/18-7/22 7/23-7/24 During
Summer
BCD
COD
TOC
SS
50.6
49.6
34.5
87.3
No Removal
9.1
No Removal
95
16.0
26.3
13.4
90.2
89.2
91.2
76.1
97.0
85.0
76.5
73.2
98.8
87.5
78.7
74.8
97.5
The above results point to a release of soluble organics from the
digesting sludge in the septic tank during the last five to six weeks of
operation. This release can probably best be explained by the occurrence
of incomplete anaerobic digestion in the septic tank. As discussed by
Eckenfelder and O'Connor (8), complete anaerobic digestion occurs in three
phases. These phases are the acid fermentation phase, the acid regression
phase, and the alkaline fermentation phase, also known as the methane
phase. In the acid fermentation phase, complex organics are hydrolyzed,
fermented, and biologically converted to less complex organics such as
acetic and propionic acid. Nitrogenous compounds are converted to ammonia
to some degree in this phase also. In the acid regression phase, the
volatile and organic acids, and soluble nitrogenous compounds are further
broken down to form ammonia, amines, acid carbonates, and small quantities
of carbon dioxide, nitrogen, methane, and hydrogen. This activity is
accomplished by a group of facultative and anaerobic bacteria called the
acid formers. The third, or methane phase, occurs when a highly special-
ized and sensitive group of bacteria, known as the methane formers,
continue the fermentation of the volatile and organic acids to methane,
and carbon dioxide, thus stabilizing the waste. If only the acid phases
of anaerobic digestion are taking place, and no methane formation occurs,
the resulting supernatant would be high in soluble organics such as the
above mentioned volatile and organic acids, and in ammonia.
The occurrence of incomplete anaerobic digestion was indicated by an
increase in soluble organics, as well as by the lack of continuous vig-
orous bubbling at the septic tank surface. Since the temperature of the
tank never exceeded 70°F, and the camp only lasted for 11 weeks, the rapid
growth of methane forming bacteria would not be favored. As noted earlier,
pH also fell through the septic tank during the latter .period, again point-
ing to incomplete digestion. It is recommended that 1 to 2 feet of well
digested sludge from a functioning digester be pumped into the septic tank
at the start of each season to encourage good digestion from the outset
and avoid the problems mentioned above.
30
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BIO-DISC UNIT PERFORMANCE
Figure 13 shows that the average weekly BOD and COD percent removals
through the bio-disc tended to increase with time up to about the fifth
to sixth week of operation. This result seems to correspond to biomass
development, which was essentially complete by the beginning of the fifth
week when all stages reached their maximum coverage. As noted in a
previous section, after about the fifth or sixth week, the waste fed to
the bio-disc was septic and increased in strength due to decreased
removals in the septic tank. Despite these problems, the bio-disc
provided treatment that was comparable to conventional activated sludge
systems. The average BOD of the settled and effluent waste respectively
was 210 and 32 mg/1 (see Table 3) yielding an efficiency of 85 percent.
This represents 82 percent of the total BOD removal. The unit removal of
85 percent was somewhat lower than that provided by bio-disc units treat-
ing fresh wastes which have been reported (3,5,6,7) to achieve 90 percent
removal of BOD applied. Considering COD removal, 71 percent was removed
across the bio-disc unit resulting in an average effluent value of 120
mg/1. This represents a removal of 67 percent of the total COD applied
to the plant. TOG removal through the unit was 71 percent or 82 percent
of the total TOG removed.
Since the actual average flow of 14.63 cu m/day (3860 gpd) was well
below design flow 33.73 cu m/day (8900 gpd), the bio-disc and final
clarifier had relatively high detention times of 3.5 hours and 7.6 hours
respectively. The biological solids entering the clarifier settled well
providing an average SS concentration in the plant effluent of 8 mg/1.
Overflow rate in the clarifier was extremely low at 3.12 cu m/day/sq m
(66.5 gpd/ft2).
Organic Loading
Although the strength of the waste applied to the bio-disc unit was
relatively high for a domestic waste, low flows tempered this effect to
produce low organic loadings. As will be shown later, an estimated organic
load factor (O.L.F.) for this plant was 0.08 gm BOD/day/gm MLSS. This
value is considerably below the normal range of 0.25-0.45 in which con-
ventional activated sludge plants operate. It is however, within the
normal operating range of extended aeration activated sludge plants.
A comparison to the organic loading on a unit studied by-Antonie (3)
was made by expressing organic loading as gms BOD applied to the discs
per day per square meter of disc surface area. The average loading at
the Horseshoe Plant was 6.58 gms BOD/day/sq m (1.35 Ib BOD/day/103 ft2).
The majority of loadings in Antonie's study ranged from 9.27 to 15.12 gms
BOD/day/sq m (1.9 to 3.1 Ibs BOD/day/103 ft2). These values and the O.L.F.
expressed above indicated that the Horseshoe Plant operated at relatively
low organic loadings. Because of these low loadings, the bacteria on the
discs existed in a food limiting environment. In such an environment,
removal of organics is affected only by the ability of the bacteria to
31
-------
100 -
0)
o
S-l
a)
cu
o
c
D
CO
O
a)
Legend:
O O - COD Removal
Q Q - BOD Removal
30
Start-
up
10
Time (weeks)
Figure 13. Average Weekly Bio-Disc Unit Removal Efficiencies
32
-------
metabolize the waste, if no reaction limiting conditions (such as low
temperature, D.O., or toxicity) exist. Since organic loadings were low
and no rate limiting conditions existed, the operation of the bio-disc
unit was relatively unaffected by the variation in organic loading
encountered. Thus, plots of BOD, COD, and TOG percent removal versus
organic loading expressed as gm of BOD, COD, and TOG applied per day
showed no trend and are not presented here.
Hydraulic Loading
Figure 14 shows the effect of hydraulic loading on BOD removal
efficiency. Hydraulic loading is expressed as cubic meters of sewage
applied to the discs daily per thousand square meters of disc surface
area cu m/day/lO^ sq m. Hydraulic loadings at the Camp Horseshoe Plant
were low, ranging from 4.07 to 40.7 cu m/day/10^ sq m (0.1 to 1.0
gpd/ft2). Loadings reported in other studies have ranged from 40.7 to
203.5 cu m/day/10-* sq m (1 to 5 gpd/ft2) (3,6) and 81.4 to 488.4 cu
m/day/103 sq m (2 to 12 gpd/ft2) (7).
As may be seen from Figure 14, BOD removal efficiencies across the
unit decreased as hydraulic loading increased. This relationship was
reported in other studies (3,6,7). The relationship is fairly well
defined at the high end of the loading range and poorly defined at the
low end. As with organic loadings, low hydraulic loadings have little
effect on disc performance. It should be pointed out that the entire
range encountered corresponded to the lowest range investigated by
Antonie (3). In this range, Antonie's data similarly reflected very
little effect of hydraulic loading on BOD removal. Figure 15 illus-
trates the effect of hydraulic loading on COD removal. No trend of the
data is strongly defined. Viewing the data as a band suggests that
increased hydraulic loading reduced removal efficiency of the process.
Investigation of TOG relationships revealed that hydraulic loading had
no effect on this parameter.
Biomass Characteristics
Biomass development on the discs took place rapidly. The develop-
ment of the growth progressed stage by stage, with all stages being
essentially 100 percent covered by the end of the fourth week. Average
thicknesses of growth were as follows: first stage - 0.32 cm (1/8 inch);
second stage - 0.32 cm (1/8 inch); third stage - 0.16 cm (1/16 inch);
fourth stage - 0.16 cm (1/16 inch). The maximum growth observed was
0.48 cm (3/16 inch) in some areas of the front disc. The minimum growth
noted was 0.08 cm (1/32 inch) in some areas of the rear disc.
Relatively large amounts of the growth 6.45 cm2 (covering approxi-
mately one square inch) would occasionally slough off, leaving bare
spots on the discs. This was most predominant on the very first disc
of the unit. The overall appearance of the biomass ranged from a black
33
-------
c
-------
Ul
c
OJ
o
M
0)
(X
O
c
-------
stringy growth with white gelatinous patches on first and second stages,
to a greenish-brown slime on the third and fourth stages.
Following the method of Borchardt (4), the MLVSS was calculated to
be 30,000 mg/1 at the .front of the unit, and 6000 mg/1 at the rear.
Random patches of known area of biomass were scraped from the discs and
the weight of the biomass determined. Knowing the total area of discs
and the volume of liquid in the tank, the MLVSS concentration could be
readily calculated. This technique was utilized one time taking three
6.45 sq cm (1 square inch) patches of growth and using the average weight
for calculation. The biomass weight found in this way was used to
calculate the O.L.F. of 0.08 gm BOD/day/gm MLSS mentioned earlier.
The progression of fauna noted by Torpey, et. al. (5) was evident
in this plant. Both Sphaerotilus and zoogloeal bacteria were present on
all discs, the Sphaerotilus probably functioning as the support media.
Other organisms present included ciliates (Paramecium, Carachesium,
Vorticella, Tintinnidium), rotifers (Philodina, Epiphanes), and nematodes.
Generally speaking, the non-bacterial organisms present increased
across the stages, both in types and numbers. Ciliates first appeared in
the middle of the first stage, rotifers at the end of the first stage,
and nematodes at the beginning of the second stage. Overall, the pre-
dominant protozoans were the stalked ciliates. The last stage of the
bio-disc unit, particularly the final disc, had many bare spots, possibly
resulting from animal predation of the higher organisms on the bacterial
slime. Such a progression of fauna is indicative of relatively efficient
and stable biological treatment.
Staging Effects
In order to determine the effect of staging on organic removals, a
series of eight grab samples through the disc section was taken over the
last three weeks of operation. These samples were analyzed for TOG
content after 30 minutes of quiescent settling. Figure 16 illustrates the
results showing that average cumulative removals across the stages were
as follows: first stage - 28.5 percent; second stage - 42.5 percent;
third stage - 57 percent; fourth stage - 59 percent. As can be seen, the
incremental TOG removal between the third and fourth stages was quite low.
Turbulence generated by the rotation of the discs resulted in a
definite increase in the dissolved oxygen content of the mixed liquor across
the stages. This effect is illustrated in Figure 17 where dissolved
oxygen values at the end of each stage are presented. The D.O. is shown
to increase from 0.8 mg/1 in the settled feed to 2.8 mg/1 at the last
stage. The dissolved oxygen content usually fell through the final clari-
fier due to the long detention (7.6 hours) in this unit. The increasing
dissolved oxygen levels through the bio-disc served to support the
progression of fauna through the stages noted earlier. The average
dissolved oxygen content of the feed tank (stage No. 0 on Figure 17) was
36
-------
60
fl)
o
0>
a.
50
o
E
0)
OS
8
H
0)
40 -
(0
f-<
d
3
u
-------
0)
I
3
toO
C8
4 -
0.5
I
_L
1.0 1.5 2.0 2.5
Average Dissolved Oxygen Content (mg/1)
Figure 17. Mixed Liquor Average Dissolved Oxygen
Content Across Bio-Disc Stages
3.0
38
-------
close to zero during the latter half of the project reflecting the
anaerobic conditions in the septic tank, and showing that little increase
in oxygen level took place in the buffer tank.
REMOVAL OF NITROGEN AND PHOSPHORUS
Average nitrogen values through the plant are given in Table 3.
Total nitrogen decreased through the septic tank from 75.8 to 57.4 mg/1
giving a reduction of 24 percent. As expected, most of this removal was
in the organic nitrogen fraction. The ammonia fraction actually increased
slightly in the septic tank from 39.0 to 41.3 mg/1 due to anaerobic break-
down of nitrogen containing organics in the sludge. Since the concentra-
tions of nitrite and nitrate-N nitrogen were very small through the septic
tank, the TKN values were essentially the same as the total nitrogen
c oncentrat ions.
Through the disc section, total nitrogen fell from 57.4 to 45.2 mg/1
giving an overall plant reduction of 40.3 percent. Nitrification through
the bio-disc is illustrated in Figure 18. It may be seen that the average
effluent ammonia concentration was still high at 30.9 mg/1 yielding an
ammonia reduction through the bio-disc of 25.2 percent. Effluent nitrite
and nitrate values rose from fractional values to 4.0 to 5.7 mg/1
respectively. Low nitrification was probably a. result of relatively high
concentrations of carbonaceous matter through the discs. This favored
predominance of heterotrophs and limited the activity of the nitrifiers,
even through the last stage. In studies reported by Antonie (6), it was
found that with an effluent BOD concentration of 30 mg/1, only 20 percent
of the ammonia nitrogen was removed across the discs. At the Camp Horse-
shoe Plant, effluent BCD concentration was 32 mg/1 and average ammonia
nitrogen removal across the secondary unit was 25.2 percent as noted above.
TKN showed a decrease of 37.5 percent in the disc section leaving
35.6 mg/1 as the effluent with 4.7 mg/1 of this due to organic nitrogen
and the remainder consisting of ammonia nitrogen. Total phosphorus
removals varied widely during the project (Appendix B, Table 6). Raw,
settled, and effluent phosphorus averaged 11.3, 9.2, and 9.6 mg/1
respectively. Overall plant removal was therefore 15 percent. Phosphorus
in biological waste treatment plants usually ranges from 5 to 25 percent.
The low removal of phosphorus is due, in part, to phosphorus release
which occurred during anaerobic digestion of the biological sludge.
TOTAL COLIFORM REMOVAL
Average reduction in total coliforms through the plant was 90.5
percent. This is within the range of 85 to 95 percent reduction provided
by other aerobic processes such as trickling filters and activated sludge.
Disinfection with chlorine improved the reduction in total coliforms to
99+ percent, represented by an average effluent value of 0.8 per 100
ml, as shown in Table 3.
39
-------
50
40
= Applied to
unit
= Effluent
30
"S
rt
CM
20
10
NIL
Figure 18. Average Ammonia Reduction and
Nitrification Occurring Across
Bio-Disc Unit
40
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SLUDGE ACCUMULATION
An accurate measurement of sludge accumulation in the septic tank
was impossible to obtain because of its physical arrangement. It was
estimated, however, using a probing pole that the depth of sludge at the
end of the study was approximately 30.48 cm (one foot). This would make
a sludge accumulation of 440 cu m/10® cu m of sewage treated. Accumula-
tion of sludge in primary-secondary plants has been reported to be 6900
cu m/10^ cu m sewage treated (9). This latter value was at a loading of
113.5 gms suspended solids per capita per day, or three times that of the
Camp Horseshoe plant. At any rate, sludge accumulation obviously was not
a problem at this plant. Cleaning the septic tank at the end of each
summer is more than adequate to prevent the accumulation of a large volume
of sludge.
MAINTENANCE AND OPERATOR ATTENTION
As mentioned in the introduction to this report, the maintenance and
operator attention required for a sewage treatment plant of this nature
is of great concern. Since a full-time or trained operator is seldom
available, these factors must be carefully weighed when selecting the
process to be used. The Camp Horseshoe plant operated continuously for
approximately 11 weeks during this study. During this period, a total
of only fourteen hours of maintenance time was required to keep the plant
running for an average of 1.3 hours per week. Repair time consisted of
cleaning and drying contacts in the buffer tank pump float controls (three
times), and tightening the main shaft sprocket chain (one time) for a total
of six hours. The balance of operator attention consisted of preparing
the chlorine solution three times a week for a total time of 45 minutes
per week. The operator reported that start-up and shutdown procedures
required a total of five hours.
AESTHETICS
The aesthetic impact of the bio-disc process on the camp was minimal.
The enclosing of the facility in a structure conforming to the surroundings
was a significant factor contributing to this effect. The discs them-
selves were kept out of view, noise levels were kept to a minimum, and
odors were restricted to the immediate vicinity of the plant itself. A
stale sewage smell which appeared to emanate from the septic tank was
noted inside the building during the last 2 to 3 weeks of the study. No
flies or similar insects were drawn to the plant. The casual observer
would have no indication of the contents of the building.
41
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SECTION VII
ACKNOWLEDGMENTS
The authors wish to acknowledge the contributions of several persons
whose efforts were instrumental in the completion of this project.
Mr. Dale Ashby, U. S. Forest Service Engineer, provided assistance
by selecting and installing flow measuring equipment.
Appreciation is also expressed to Mrs. Virginia Meadows and Mr.
Walter Kines. As Camp Supervisor and Treatment Plant Operator respectively,
their efforts in the daily collection of samples, the providing of infor-
mation on camp activities, and general cooperation and assistance were
invaluable.
A grant from the Environmental Protection Agency provided support
for the study. The aid of Dr. R. L. Bunch, who served as Project Officer
for the grant is gratefully acknowledged.
43
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SECTION VIII
REFERENCES
1. Welch, F. M., "Preliminary Results of a New Approach in the Aerobic
Biological Treatment of Highly Concentrated Wastes," presented at
the 23rd Purdue Industrial Waste Conference, May, 1968.
2. Birks, C. W. and Hynek, R. J., "Treatment of Cheese Processing Wastes
by the Bio-Disc Process," presented at the 26th Purdue Industrial
Waste Conference, May, 1971.
3. Antonie, R. L., "Application of the Bio-Disc Process to Treatment of
Domestic Wastewater," presented at the 43rd Annual Conference of the
Water Pollution Control Federation, Boston, Massachusetts, October,
1970.
4. Canale, R. P., ed., Biological Waste Treatment, John Wiley and Sons,
Inc. (New York), 1971, p. 32.
5. Torpey, W. N., Heukelekian, H., et. al., "Rotating Disks with
Biological Growths Prepare Wastewater for Disposal or Reuse," Water
Pollution Control Federation Journal, 43, 1971, pp. 2181 - 2188.
6. Antonie, R. L., "Three-Step Biological Treatment with the Bio-Disc
Process," presented at the New York Water Pollution Control Association
Spring Meeting, June, 1972.
7. Antonie, R. L., "The Bio-Disc Process: New Technology for the Treat-
ment of Biodegradeable Industrial Wastes," Chemical Engineering
Symposium Series, Water - 1970, Volume 67, Number 107, pp. 585 - 588.
8. Eckenfelder, W. W., Jr., and O'Connor, D. J., Biological Waste
Treatment, Pergamon Press (New York), 1961, p. 248.
9. Metcalf and Eddy, Inc., Wastewater Engineering, McGraw-Hill Book
Company (New York), 1972, p. 581.
45
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SECTION IX
GLOSSARY
BOD - Biochemical Oxygen Demand (5-day)
COD - Chemical Oxygen Demand
cm - centimeter
cu m - dubic meter
D.O. - Dissolved Oxygen
gm - gram
gpcd - gallons per capita per day
gpd - gallons per day
gpm - gallons per minute
m - meter
mg/1 - milligrams per liter
MLSS - Mixed Liquor Suspended Solids
MLVSS - Mixed Liquor Volatile Suspended Solids
NH3-N - Ammonia nitrogen
NO£-N - Nitrite nitrogen
N03-N - Nitrate nitrogen
O.L.F. - Organic Load Factor
ORG-N - Organic nitrogen
PO^-P - Phosphorus (total)
rpm - revolutions per minute
sq m - square meter
SS - Suspended Solids
T - Trace
TKN - Kjeldahl nitrogen
TOG - Total Organic Carbon
47
-------
SECTION X
APPENDICES
49
-------
APPENDIX A
FLOW MEASUREMENT
Daily flow was determined by a mass balance around the buffer tank.
The net rise and fall of the liquid level in the buffer tank was measured
by a float and recorder combination manufactured by Leupold and Stevens,
Inc. The recorder pen also traversed the chart horizontally at a fixed
rate. Knowing the vertical rise and fall in the buffer tank over a given
time period provided the net liquid volume change in the tank.
Observation of the float-recorder under all conditions of flow
revealed that two distinct types of chart traces occurred. The type of
trace produced depended upon the operation of the pumps in the buffer
tank at the time, that is, continuous or intermittent. Continuous pump
operation indicated that inflow volume was large enough to keep the
unit's feed tank full and overflowing back to the buffer tank. Inter-
mittent operation indicated only enough incoming sewage to partially
fill the feed tank before the pumps shut off again, due to the drop in
the level of the buffer tank. Knowing the net volume change in the buffer
tank and mode of pump operation provided the following general mass
balance equation:
Buffer Tank
Net Volume Change = Inflow - Outflow + Return
Where: Inflow = Overflow from septic tank
(hence raw sewage inflow)
Outflow = Quantity pumped to feed tank
Return = Overflow from feed tank back to
buffer tank with feed tank full
Rearrangement of the equation permitted the inflow to be determined
under conditions of either continuous or intermittant pump operation.
The above rather unusual method of flow measurement was used to
avoid problems of weir fouling at low flows in raw sewage. It proved to
be quite reliable and was found to be accurate by checking against several
other methods of flow determination.
50
-------
APPENDIX B
SUPPLEMENTAL DATA AND FIGURES
TABLE 6. Daily Wastewater Characteristics
Week of June II, 1972 - Week #1
BOD-5 (ma/1) COD (ma/1)
Date
6/11
6/12
6/13
6/14
6/15
6/16
6/17
Date
6/11
6/13
6/15
6/17
Date
Date
Date
6/14
6/16
Date
Raw Sett. Eff.
230 322 352
222 250 125
TOG (ma/1)
Cl
Eff. Raw Sett.
231 301 792
131 220 453
430 420
194 504
229 549
460 344
344 413
SS (mg/1)
Raw Sett. Eff. Raw Sett.
N02-N (mg/1)
Raw Sett.
No data obtained this
NH3-N (mg/1)
Raw Sett. Eff.
No data obtained this
pH (mg/1)
Raw Sett. Eff.
6.6 6.9 7.4
6.8 6.7 6.8
Total
102 420
75 105
50 87
58 118
N03-N
Eff.
669
331
276
126
378
241
80
Eff.
595
55
52
32
(mg/1)
Eff. Raw Sett.
week
TKN (mg/1)
Total
Cl
Eff.
613
268
331
240
194
254
91
Total
Solids
Eff.
200
Eff.
P (mg/1)
Raw Sett. Eff. Raw Sett.
week
D.O. (mg/1)
Raw Sett. Eff.
1.0 2.0 0.5
Coliform (per 100 ml)
Temp
Raw
22
23
Raw Sett. Eff.
Eff.
(°C)
Eff.
18
19
Cl
Eff.
No data obtained this week
51
-------
TABLE 6. (cont'd)
Week of June 18, 1972 - Week #2
BOD-5 (mg/1) COD (mg/1)
Date
6/18
6/19
6/20
6/21
6/22
6/24
Date
6/19
6/21
6/22
6/24
Date
Date
Date
6/18
6/20
6/22
6/24
Date
6/20
6/22
6/24
* Data
Raw Sett. Eff.
410 180 34
253 216 45
TOG (mg/1)
Raw Sett. Eff.
100 80 36
85 60 36
50 90 28
20 17 7
N02-N (mg/1)
Raw Sett.
No data obtained this
NH3-N (mg/1)
Cl
Eff. Raw Sett.
59 530 248
24 518 338
248 113
530 ' 195
427 280
40* 136*
SS (mg/1)
Raw Sett.
292 80
520 68
370 110
30 18
NO -N
Gl
Eff. Eff.
68
180
79
48
70
107*
Total
Solids
Eff. Eff.
22
20 100
20
7
(mg/1)
Eff. Raw Sett. Eff.
week
TKN (mg/1)
Raw Sett. Eff. Raw Sett. Eff. Raw
No data obtained this
pH (mg/1)
Raw Sett. Eff.
week
D.O. (mg/1)
Raw Sett. Eff.
1.25 0.75 0.5
6.55 6.8 6.7
6.7 6.8 6.6 2.5 4.0 3.5
6.15 6.2 6.8 3.5 5.25 5.5
Total Coliform (per 100 ml)
Raw Sett
870 x 106 290 x
not used
Eff.
106 12 x 106
Total
P (mg/1)
Sett. Eff.
Temp (°C)
Raw Eff.
28 19
18 18
15 15
13 13
Cl
Eff.
0.0
0.0
14.0
52
-------
TABLE 6. (cont'd.)
Week of June 25, 1973 - Week #3
BOD-5 (mg/1) GOD (mg/1)
Date
6/26
6/27
6/28
6/29
6/30
7/1
Raw
492
231
Sett.
150
85
Cl
Eff. Eff. Raw Sett.
44 1410* 82
1060* 276
192 196
652 204
434 182
16 60 446 248
Eff.
43
73
159*
73
70
66
Cl
Eff.
30
21
Total
TOG (mg/1)
Date
6/26
6/27
6/29
6/30
7/1
Date
6/26
Date
6/26
Date
6/28
6/30
Date
6/28
6/30
*Data
Raw
175
364
136
Raw
0.01
NH
3
Raw
36.4
pH
Raw
6.5
6.9
Raw
6
720 x 10
not used
Sett.
27
115
90
N02-N (n
Sett.
SS (mg/1)
Eff. Raw Sett.
15 1170* 90
24 1980* 135
24
445 80
285 60
ig/1) N03-N
Solids
Eff.
5
7
27
27
(mg/1)
Eff. Raw Sett.
0.01 4.87 T
-N (mg/1)
TKN (mg/1)
0.04
Total
P (mg/1)
Sett. Eff. Raw Sett. Eff. Raw Sett.
12.2
(mg/1)
Sett.
7.0
6.5
6.05 75.8 15.9 8.29 10
D.O. (mg/1)
Eff. Raw Sett. Eff.
6.9 0.25 5.0 5.5
6.6 0.5 6.0 3.5
Total Coliform (per 100 ml)
Sett. Eff.
6 6
230 x 10 9 x 10
.1 4.0
Temp
Raw
17
16
Eff.
425
Eff.
9.4
Eff.
3.44
(°C)
Eff.
16
17
Cl
Eff.
0.0
0.0
53
-------
TABLE 6. (cont'd.)
Week of July 2, 1972 - Week #4
BOD-5 (mg/1) COD (mg/1)
Date
7/2
7/3
7/4
7/5
7/6
7/8
Raw
295
332
Cl
Sett. Eff. Eff.
100 16 49
113 29 37
TOG (mg/1)
Date
7/3
7/5
7/6
7/8
Date
7/5
Date
7/5
Date
7/5
7/7
Raw
112
144
106
Raw
0.01
NH3
Raw
12.1
pH
Raw
6.8
6.7
Sett. Eff. Raw
80 31 575
45 16 870
630
40 22 555
N02-N (mg/1)
Sett. Eff.
0.23 4.1
Raw Sett.
555 290
781 392
748 368
523 192
1313* 155
324 174
SS (mg/1)
Sett.
52
97
62
17
NO -N
Eff.
112
103
107
90
90
56
Eff.
20
37
32
1
(mg/1)
Raw Sett.
0.04 1
-N (mg/1) TKN (mg/1)
.19
Total
Cl
Eff.
107
219
93
Total
Solids
Eff.
365
Eff.
0.4
P (mg/1)
Sett. Eff. Raw Sett
17.6 16.7 23.4 26.4
(mg/1) D.O.
Sett. Eff. Raw
6.5 6.75
7.0 7.1 0.75
Eff. Raw
Sett.
16.7 6.42 3.85
(mg/1)
Sett. Eff.
4.5 4.5
Temp
Raw
16
16
Eff.
3.65
(°C)
Eff.
18
16
Total Coliform (per 100 ml)
Date
7/7
*Data
Raw
400 x 106
not used
Sett.
220 x 106
Eff.
180 x 106
Cl
Eff.
0.0
54
-------
TABLE 6.
Date
(cont'd.)
Week of July 9, 1972 - Week #5
BOD-5 (mg/1) COD (mg/1)
Raw
Sett. Eff.
Gl
Eff.
Raw
Sett.
Eff.
Gl
Eff.
7/9
7/14
7/15
Date
490 134 93 69
325 186 32 40 976 420 120 162
295 182 47 81 468 298 137 183
Total
TOG (mg/1) SS (mg/1) Solids
Raw
Sett.
Eff.
Raw
Sett.
Eff.
Eff.
7/9
7/14
7/15
Date
100
252
145
32
187
140
N0-N
19
50
45
505
360
110
37
14
8
10
3
1
335
N03-N
Raw
Sett.
Eff.
Raw
Sett.
Eff.
Date
No data obtained this week
NH3-N (mg/1) TKN (mg/1)
Total
P (mg/1)
Raw Sett. Eff. Raw Sett. Eff. Raw Sett. Eff.
No data obtained this week
pH (mg/1) P.O. (mg/1) Temp (°C)
Raw Sett. Eff. Raw Sett. Eff. Raw Eff.
No data obtained this week
Total Goliform (per 100 ml)
Date
Date
Raw
Sett.
Eff.
Gl
Eff.
No data obtained this week
55
-------
TABLE (cont'd.)
Week of July 16, 1972 - Week #6
BOD-5 (mg/1)
COD (mg/1)
Date
7/16
7/17
7/18
7/19
7/20
7/21
7/22
Raw
137
300
Gl
Sett. Eff. Eff.
192 37 45
147 46 30
TOG (mg/1)
Date
7/16
7/17
7/19
7/21
7/22
Date
7/17
Date
7/17
Date
7/16
7/18
7/20
7/22
Raw
182
1085
Raw
T
NH,
Raw
21.5
pH
Raw
7.2
7.1
6.7
7.4
Sett. Eff. Raw
50 31 2790
135
610
50 15 460
180
NO,-N (mg/1)
£
Sett. Eff.
0.02 4.3
Raw Sett.
1480* 267
1545* 281
309 280
540 309
790 268
800 250
1050 400
SS (mg/1)
Cl
Eff. Eff.
160 246
97 109
77
82
69
66
100
Total
Solids
Sett. Eff. Eff.
40 0.
9 0.
5 3
6 0.
9 2
N03-N (m
Raw Sett
0.17 0.23
-N (mg/1) TKN (mg/1)
Sett. Eff. Raw Sett
37.8 24.5 48.1 53.7
(mg/1) D.O.
Sett. Eff. Raw
6.9 7.1 2.0
6.9 7 . 05
6.95 7.1
6.95 7.0 1.5
Eff. Raw
32.0 11.3
(mg/1)
Sett. Eff.
1.0 0.5
2.5 0.25
5
4
280
75
g/D
Eff.
7.2
Total
P (mg/1)
Sett. Eff.
11.1 11.1
Temp (°C)
Raw Eff.
20 22
19.5 22
22 22
21 23
Total Coliform (per 100 ml)
Date
7/16
7/18
7/20
*Data
Raw
c.
560 x 10b
not used
Sett.
A
120 x 10°
Eff.
0.0
Cl
Eff.
0.0
0.0
0.0
56
-------
TABLE 6. (cont'd.)
Week of July 23, 1972 - Week #7
BQD-5 (mg/1) COD (mg/1)
Date
7/24
7/25
7/26
7/27
7/28
7/29
Raw
123
218
Sett.
253
183
Eff.
6
16
Cl
Eff.
10
12
Raw
562
608
262'
413
332
908
Sett.
650
475
504
400
288
490
Eff.
296
149
97
97
105
72
Cl
Eff.
189
101
Date
7/25
7/26
7/27
7/28
7/29
Raw
73
60
93
112
TOG (mg/1)
Sett.
65
78
90
62
' Eff.
23
19
19
25
Raw
230
230
160
865
SS (mg/1)
Sett.
9
6
17
8
Eff.
2.5
1.0
2.5
0.5
Total
Solids
Eff.
390
Date
N02-N
N03-N
Raw
Sett.
Eff.
Raw
Sett.
Eff
7/27
0.02
0.24
10.0
NH -N (mg/1) TKN (mg/1)
Date
7/27
Raw
57.3
Sett.
39.5
Eff.
28
Raw
73.1
Sett.
56.2
Eff.
33.76
Raw
12.6
Total
P (mg/1)
Sett.
12.6
Eff.
4.2
pH (mg/1)
P.O. (mg/1)
Temp (°C)
Date
7/24
7/26
7/28
Raw
6.9
6.4
Sett.
6.7
6.7
Eff.
6.6
7.0
Raw
2.0
0.1
Sett.
3.0
4.5
Eff.
0.5
0.1
0.5
Raw
21
22
20
Eff.
23
20
22
Total Coliform (per 100 ml)
Date
7/26
7/28
Raw
500 x 106
Sett.
230 x 106
Eff. - -
40 x 106
Cl
Eff.
0.0
0.0
57
-------
TABLE 6. (cont'd.)
Week of July 30, 1972 - Week #8
BOD-5 (mg/1)
COD (mg/1)
Date
7/30
7/31
8/1
8/2
8/3
8/4
8/5
Raw
211
148
Cl
Sett. Eff. Eff. Raw Sett.
319 485
390 465
925 449
841 445
205 57 56 359 336
228 63 70 363 383
700 436
TOG (mg/1) SS (mg/1)
Date
7/30
7/31
8/2
8/3
8/4
Date
8/1
Date
8/1
Date
7/30
8/1
8/3
Date
7/30
8/1
8/3
Raw
100
125
100
95
Raw
T
NH-
Raw
58.8
pH
Raw
6.65
6.1
7.8
Raw
6
520 x 10
Sett. Eff. Raw Sett.
117 17
125 22 150 12
195 5
88 31 180 11
122 40 185 10
NO_-N (mg/1) NO -N
/ J
Cl
Eff. Eff.
68 151
159 79
88 116
100 114
136
172
136
Total
Solids
Eff. Eff.
3.4
2
3
7.5 580
(mg/1)
Sett. Eff. Raw Sett. Eff.
0.01 3.67 0.42 0.
-N (mg/1) TKN (mg/1)
Sett. Eff. Raw Sett. Eff. Raw
41.3 33.5 139.3 60.4 40.2 12.0
(mg/1) D.O. (mg/1)
Sett. Eff. Raw Sett. Eff.
6.3 6.2 1.75 0.5 2.25
6.6 7.0 0.5 0.75 0.5
6.55 7.0 0.75
Total Coliform (per 100)
Sett. Eff.
6 6
210 x 10 90 x 10
23 6.5
Total
P (mg/D
Sett. Eff.
9.8 15
Temp (°G)
Raw Eff.
18 19
19 20
19 22
Gl
Eff.
0.0
0.0
0.0
58
-------
TABLE 6. (cont'd.)
Week of August 6, 1972 - Week #9
BOD-5 (mg/1)
COD (mg/1)
Date
8/6
8/7
8/8
8/9
8/10
8/11
8/12
Raw
244
299
Sett.
138
TOG (mg/1)
Date
8/6
8/7
8/8
8/10
8/11
8/12
Date
8/11
Date
8/11
Date
8/7
8/9
8/11
Date
8/7
8/9
8/11
Raw
217
205
115
112
Raw
T
NHo
Raw
64.3
pH
Raw
7.05
7.45
7.05
Raw
f.
540 x 10
Sett.
150
120
102
92
N02-N (n
Sett.
T
-N (mg/1)
Cl
Eff. Eff. Raw Sett.
13 11 682 546
15 21 1040 667
772 517
834 1145
656 463
1012 597
614 440
SS (mg/1)
Eff.
240
159
166
151
174
108
120
Eff. Raw Sett. Eff.
190 15 2.
34
41 465 15 6.
175 12 5.
32
30 220 11 10
ig/1) N03-N (m
Eff. Raw Sett
2.77 0.27 0.32
TKN (mg/1)
75
5
75
g/D
•
Total
Cl
Eff.
213
199
Total
Solids
Eff.
430
Eff.
0.8
P (mg/1)
Sett. Eff. Raw Sett. Eff. Raw
78.5
(mg/1)
Sett.
6.3
6.9
7.0
80 86.5 102.1 85.5 11.2
D.O. (mg/1)
Eff. Raw Sett. Eff.
7.2 0.5 1.0 1.0
7.45
7.5 2.5 1.5 1.5
Total Coliform (per 100 ml)
Sett. Eff.
fi 6
230 x 10b 100 x 10°
Sett.
10.8
Temp
Raw
20
19
21
Eff.
15.6
(°C)
Eff.
21
21
19
Gl
Eff.
0.0
0.0
0.0
59
-------
TABLE 6 (cont'd.)
Week of August 13, 1972 - Week #10
BOD-5 (mg/1) COD (mg/1)
Date
8/13
8/14
8/15
8/16
8/17
8/18
8/19
Date
8/13
8/14
8/15
8/16
8/17
8/18
Date
Date
Date
8/13
8/15
8/17
8/19
Raw Sett. Eff.
175 256 36
176 330 12
TOG (mg/1)
Raw Sett. Eff.
120 155 66
100 155 32
151 172 26
75 150 10
NOo-N (mg/1)
^
Raw Sett.
No data obtained this
NH,-N (mg/1)
Cl
Eff. Raw Sett.
814 688
513 366
60 304 688
394 328
7 361 616
779 410
685 780
SS (mg/1)
Raw Sett.
520 9
120 11
310 11
155 13
N03-N
Cl
Eff. Eff.
143
209
170 153
160 145
107
90
123
Total
Solids
Eff. Eff.
1.25
1.0
1.25
1.0 340
(mg/1)
Eff. Raw Sett. Eff.
week
TKN (mg/1)
Raw Sett. Eff. Raw Sett. Eff. Raw
No data obtained this
pH (mg/1)
Raw Sett. Eff.
6.8 7.4 7.7
7.75 7.2 7.45
6.8 6.85 6.5
week
D.O. (mg/1)
Raw Sett. Eff.
0.6 0.4 0.5
2.5 0.75 2.0
2.0 0.5 1.25
Total
P (mg/1)
Sett. Eff.
Temp (°C)
Raw Eff.
20 22
19 21
20 21
19 22
Total Coliform (per 100 ml)
Date
8/13
8/17
8/19
Raw Sett
210 x 106 180 x
Eff.
6
10 0
Cl
Eff.
0.0
2.0
0.0
60
-------
TABLE 6. (cont'd.)
Week of August 20, 1973 - Week #11
BOD-5 (mg/1) COD (mg/1)
Date
8/20
8/21
8/22
8/23
8/24
Date
8/20
8/21
8/22
8/23
8/24
Date
8/20
8/23
8/25
Date
8/20
8/23
8/24
Date
8/21
8/23
8/24
• Raw
521
316
Raw
155
157
187
200
Raw
T
T
T
NH
Raw
23.4
29.1
15.3
PH
Raw
6.75
7.05
Sett. Eff.
355 38
494 40
TOG (mg/1)
Sett. Eff.
187 63
155 44
172 54
130 37
N02-N (mg/1)
Sett.
T
T
0.01
-N (mg/1)
Cl
Eff.
5
20
Raw
175
180
170
155
Eff.
4.25'
2.7
5.65
Raw Sett.
1475* 836
589 621
1219 490
1016* 677
387 1225
SS (ma/1)
Eff.
175
191
143
177
129
Sett. Eff.
15 2.
15 3.
15 1.
15 1.
N03-N (m
Raw Sett
0.27 0.41
0.9 0.34
0.67 0.37
TKN (mg/1)
24
25
25
25
g/D
•
Total
Cl
Eff.
139
145
Total
Solids
Eff.
310
Eff.
11.6
0.24
4.4
P (mg/1)
Sett. Eff. Raw Sett. Eff. Raw
55.6 7.95 47
64.5 44.9 73
67 29.9 63
(mg/1)
Sett. Eff.
7.1 7.4
7.0 7.2
.5 74.7
.4 84.4
.3 83.9
D.O
Raw
1.5
1.25
Total Coliform
Date
8/21
8/25
*Data
Raw
140 x 10
not used
Sett
6 90 x
.
106
7.95 17
54.6 15
35.5 13
. (mg/1)
Sett. Eff.
0.5 2.25
0.5 1.75
(per 100 ml)
Eff.
10 x 106
Sett.
15
10.
11.
Temp
Raw
19
20
20
Eff.
15.5
5 13.2
2 14.8
(°C)
Eff.
19
21.5
22
Cl
Eff.
2.0
0.0
61
-------
TABLE 7
Daily Sewage Flows - 1972
Date Day of Week Flow (cu m)
7/01
7/02
7/03
7/06
7/07
7/08
7/12
7/13
7/14
7/15
7/16
7/17
7/18
7/19
7/20
7/21
7/22
7/23
7/24
7/25
7/26
7/27
7/28
7/29
7/30
Saturday
Sunday
Monday
Thursday
Friday
Saturday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Fr iday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
16.86
12.26
12.97
15.51
5.54
9.67
10.20
14.75
16.28
17.29
17.85
23.26
17.17
20.69
19.87
19.68
9.77
5.96
18.86
22.48
17.00
17.07
18.19
8.58
13.66
Date Day of Week Flow (cu m)
7/31
8/01
8/02
8/03
8/04
8/05
8/06
8/07
8/08
8/09
8/10
8/11
8/12
8/13
8/14
8/15
8/16
8/17
8/18
8/19
8/20
8/21
8/22
8/23
8/24
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Wednesday
Thur sday
18.09
20.40
22.08
17.02
13.89
8.62
12.23
21.53
18.31
23.93
12.37
22.91
7.02
zero
4.03
16.10
16.26
16.00
7.68
4.12
9.63
14.68
14.60
17.29
10.63
Note: 1 cu m = 264.1 gallons
62
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TABLE 8
Comparison of Wastewater Characteristics for
Time Periods 6/18/72 to 7/22/72 and
7/23/72 to 8/24/72
6/18/72 to 7/22/72
BOD
COD
TOG
SS
Raw (mg/1)
305.8
494.4
113.2
393.8
Settled (mg/1)
151.5
249.1
73.5
49.8
Effluent (mg/1)
32.8
92.7
26.6
12.4
7/23/72 to 8/24/72
BOD
COD
TOG
SS
Raw (mg/1)
213.3
615.0
122.7
251.5
Settled (mg/1)
252.8
559.5
124.3
11.8
Effluent (mg/1)
31.8
144.0
33.2
2.8
NOTE: BOD time periods are 6/18/72 - 7/15/72 and 7/16/72
8/24/72
63
-------
5001-
§
PQ
400
300
200
100
6/18
7/16
6/25
7/2
7/30
7/9
Legend: Q— — O " 6/18 to 7/15
O — Q - 7/16 to 8/24
7/15
7/23 7/30 8/6
Calendar Date (1972
8/13
8/20
8/27
Figure 19. Comparison of Raw BOD Values Before and After
First Five Weeks of Plant Operation
-------
500-
400
Ul
§
•o
(U
•W
4-1
(1)
300
200
100
Legend: o——O- 6/18 to 7/15
O o- 7/16 to 8/24
6/18
6/25
7/2
7/9
7/15
7/16
7/23 7/30 8/6
Calendar Date (1972)
8/13
8/20
8/27
Figure 20. Comparison of Settled BOD Values Before and
After First Five Weeks of Operation
-------
§
0)
W
70 -
60
50
40
30
20
10
6/18 to 7/15
7/16 to 8/24
7/16
7/23
8/20
8/27
Calendar Date (1972)
Figure 21. Comparison of Effluent BOD Values Before and
After First Five Weeks of Operation
-------
1100
1000
800
600
§
§ 400
200
0
6/18
Legend: Q——O - 6/18 to 7/22
O o- 7/23 to 8/24
7/2
7/23
7/9
f
7/16
7/22
'/30 8/6 8/13
Calendar Date (1972)
8/20
8/27
Figure 22. Comparison of Raw COD Values Before and
After First Six Weeks of Operation
-------
1100
1000
800
600
CO
4J
4J
0)
400
200
8/13
Calendar Date (1972)
7/16
8/20
- 6/18/ to 7/22
—Q - 7/23 to 8/24
1(22
8727
Figure 23. Comparison of Settled COD Values Before and
After First Six Weeks of Operation
-------
a
o>
3
w
250
200
150
100
50
Legend: O——O - 6/18 to 7/22
O O - 7/23 to 8/24
6/18
6/25
7/2
7/9
7/16
7/22
7/23
7/30 8/6 8/13
Calendar Date (1972)
8/20
J/27
Figure 24. Comparison of Effluent COD Values Before and
After Six Weeks of Operation
-------
400
300
200 .
o
o
H
Pi
100
6/18
Legend: O—O- 6/18 to 7/22
O O- 7/23 to 8/24
6/24
7/2
-h-
7/9
7/16
7/22
7/23
7/30 8/6 8/13
Calendar Date (1972)
8/20
8/27
Figure 25. Comparison of Raw TOG Values Before and
After First Six Weeks of Operation
-------
200
Legend: O—O- 6/18 to 7/22
X___X- 7/23 to 8/24
150
100
4J
4-1
-------
80
60
Legend: Q O - 6/18 to 7/22
o - 7/23 to 8/24
ro
8
H
c
-------
O
C/3
0)
T3
c
s.
M
3
OJ
1000 -
800-
600-
400-
200-
Legend: O O- 6/18 to 7/22
O O- 7/23 5o 8/24
7/23
7/30
8/6 8/13
Calendar Date (1972)
8/20
8/27
Figure'28. Comparison of Raw Suspended Solids Values Before and
1 After First Six Weeks of Operation
-------
CO
T3
•rH
,-(
O
CO
-o
0)
•a
c
-------
O
CO
0)
•a
-------
APPENDIX C
DISCUSSION OF CHLORINATED VALUES
The average values of BOD and COD in the final effluent were
32 mg/1 and 120 mg/1 respectively, while the BOD and COD of the
chlorinated effluent were 50 mg/1 and 172 mg/1. The higher average
chlorinated effluent values were not anticipated since the chlorine is
expected to oxidize a small fraction of the wastewater organics. Although
the average strength of the chlorinated waste was higher, examination
of Appendix B, Table 6 will show that in many cases the reverse was true
for individual samples.
The higher average COD's could have been caused by chloride inter-
ference if not enough HgS04 was added to eliminate this problem. However,
since the average total solids concentration of the effluent was only
355 mg/1, the waste obviously did not have an unusually high chloride
concentration, and the 0.4 gm of HgSO^ recommended by Standard Methods
should have been more than adequate. In addition, chloride interference
could not have caused the higher BOD values.
It was observed during the project that a scum layer of oil and
grease formed in the chlorine contact chamber at times. When this was
noticed, sample takers were instructed to sample below this layer.
However, it is now believed that organics concentration in this layer
are responsible for the erroneously high values of BOD and COD in the
chlorinated effluent.
76
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1. Report No.
3. Accession No.
w
4. Title
EVALUATION OF THE BIO-DISC TREATMENT PROCESS FOR SUMMER
CAMP APPLICATION
7. Author(s)
Sack, William A. and Phillips, Stephen A.
9. Organization
Civil Engineering Department
West Virginia University
Morgantown, W. Va. 26506
12. Sponsoring Organization
IS. Supplementary Notes
Environmental Protection Agency report number,
EPA-670/2-73-022, August 1973.
5. Report Date
6.
8. Performing Organization
Report No.
10. Project No.
S-800707
/. Contract/Grant No.
13. Type of Report and
Period Covered
16. Abstract
The bio-disc wastewater treatment process was evaluated during operation for one
summer at a recreational camp. The bio-disc section consisted of four stages, each
of 22 polystyrene discs 1.98 m (6.5 ft) in diameter, and was preceeded by a septic
tank that served to handle both the primary and the biological sludge produced.
Evaluation of the plant included time required for start-up, organic removal
efficiency, response to flow variations, nutrient removals, aesthetic impact, and
required maintenance and operation attention.
Overall organic removals reached essentially full efficiency by the end of the
first week of operation. However, removals across the bio-disc section continued to
increase somewhat till about the fifth or sixth week of operation. Average bio-disc
unit percent removals were BOD - 84.5, COD - 71, TOG - 71, and suspended solids - 75.
Average overall plant percent removals were 87.5, 79, 75, and 97.5 respectively.
Total nitrogen removal through the plant averaged 40.3 percent. Ammonia nitrogen
removal in the disc section was only 25.2 percent. Overall total phosphorus removal
was 15 percent. Maintenance and operational requirements for the plant were minimal
requiring an average of 1.3 hours per week during the summer.
17a. Descriptors
*Wastewater Treatment, *Biological Treatment, Nutrient Removal
176. Identifiers
*Bio-disc Process, *Rotating Biological Contractor, *Tauchtropkorper
17c. COWRR Field & Croup
18. Availability
19. Security Class.
(Report)
20. Security Class.
(Page)
21.
No. of
Pages
Send To:
22. Price
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
Abstractor William A. Sack
[ institution West Virginia University, MorgantTJwn, W. V«
WRSIC 102 (REV. JUNE 1971)
GPO 913.281
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