WATER POLLUTION CONTROL RESEARCH SERIES 12060EZP 09/70
Cannery Waste Treatment
Kehr Activated Sludge
U.S. DEPARTMENT OF THE INTERIOR FEDERAL WATER QUALITY ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the results and
progress in the control and abatement of pollution of our Nation's
Waters. They provide a central source of information on the research,
development and demonstration activities of the Federal Water Quality
Administration, Department of the Interior, through in-house research
and grants and contracts with Federal, State, and local agencies, re-
search institutions, and industrial organizations.
Water Pollution Control Research Reports will be distributed to reques-
ters as supplies permit. Requests should be sent to the Project Reports
System, Office of Research and Development, Department of the Interior,
Federal Water Quality Administration, Washington, D.C. 20242
Previously issued reports on the Food Processing/Industrial Pollution
Control Program:
1206010/69 Current Practice in Potato Processing
Waste Treatment
12060FADIO/69 Aerobic Treatment of Fruit Processing
Wastes
1608011/69 Nutrient Removal From Cannery Wastes
By Spray Irrigation of Grassland
12060EHT07/70 Use of Fungi Bnperfecti in Waste Control
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Cannery Waste Treatment
Kehr Activated Sludge
by
Environmental Engineering Department
Central Engineering Laboratories
FMC Corporation
P. 0. Box 580
Santa Clara, California 95052
for the
FEDERAL WATER QUALITY ADMINISTRATION
U. S. DEPARTMENT OF THE INTERIOR
Grant No. 12060 EZP
September 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price 70 cents
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FWQA Review Notice
This report has been reviewed by the Federal Water
Quality Administration and approved for publication.
Approval does not signify that the contents necessarily
reflect the views and policies of the Federal Water
Quality Administration, nor does mention of trade
names or commercial products constitute endorsement
or recommendation for use.
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ABSTRACT
The Kehr Activated Sludge Process (KASP), as practiced at FMC Corpor-
ation's Central Engineering Laboratories, uses a completely mixed
aeration tank with no intentional sludge wasting. The concentration
of mixed liquor suspended solids was allowed to stabilize at some
value as a result of cellular synthesiss endogenous loss, and washout
in the effluent. The concentration of mixed liquor suspended solids
ranged from 4,000 to 129000 mg/liter. The BODc of domestic sewage
and cannery wastes varied from 200 to 2000 mg/liter.
Removals obtained were 80 percent reduction in the concentration of
total organic carbon and 90 percent reduction in the concentration
of BOD5.
The process was able to undergo a 48-hour period of no organic load-
ing with no loss of treatment efficiency when the organic load was
returned. The KASP appears to have an application for pretreatment
of industrial wastes prior to discharge to a municipal sewer. The
KASP, when used in this manner, could handle intermittent waste
discharge, produce 90 percent BOD5 removal and provide aerobic
digestion within the aeration tank.
Exclusive of any primary treatment, the cost of treating 10 mgd of.
a waste containing 250 mg/liter of BOD5 using this high solids
activated sludge process is about 7i per thousand gallons using
gravity settling and about 29tf per thousand gallons using electro-
flotation. The cost of pretreating 1 mgd of a waste containing
2,000 mg/liter BOD is about 28<£ per thousand gallons exclusive of
primary treatment.
This report was submitted in fulfillment of Grant 12060 EZP between
the Federal Water Quality Administration and the FMC Corporation.
Key Words: Cannery Pastes, industrial waste pretreatment, activated
sludge process, aerobic digestion, electroflotation.
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CONTENTS
Section Page
I Conclusions 1
II Introduction 3
III Test Facility and Equipment 5
Permanent Facility 5
Experimental Facilities 5
IV Experimental Program 11
Biological System 11
Flotation System 11
Laboratory Analyses 11
V Experimental Procedure 13
Tracer Washout Study 13
Biological System 13
Flotation System 14
VI Results 15
Tracer Washout 15
Continuous Operation of KASP 15
Artificial Shock Loading 25
Flotation System 30
Electroflotation Costs 32
VII Economic Evaluation 39
VIII Discussion 41
IX Acknowledgments 45
X References 47
XI Appendices 49
Kehr Process Operational Data 49
Electroflotation Theory 66
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FIGURES
No. Page
1 Flow DiagramPermanent and Experimental Facility 6
2 Kehr Activated Sludge Plant 7
3 Diurnal Flow Pattern 9
4 Continuous Flow Flotation Cell 10
5 Tracer Washout Curve for the Kehr Process Aeration Tank . . 16
6 Tracer Washout Curve for the Kehr Process Aeration Tank . . 17
7 TOC Data for the Kehr Process for Continuous Operation . . 19
8 Kehr Process BOD Data for Continuous Operation 20
9 Diurnal Variation of Kehr Process TOC 21
10 Diurnal Variation of Kehr Process Nitrogen 23
11 Diurnal Variation of Kehr Process Phosphate 24
12 Effluent BOD5 as a Function of Time for the Shock
Loading Study 26
13 Effluent Suspended Solids as a Function of Time for
the Shock Loading Study 27
14 Effluent TOC as a Function of Time for the Shock
Loading Study 28
15 Effluent Nutrient Concentration as a Function of Time
for the Shock Loading Study 29
16 Data for the Electroflotation of Kehr Process Mixed
Liquors 31
17 Current Density as a Function of Cell Voltage for
Different Mixed Liquor Conductivities 34
18 Current Density as a Function of Cell Voltage for
Different Electrode Spacings 35
19 Daily Power and Anode Costs for Electroflotation as
a Function of Current Density 37
A-I Correlation of BOD with TOC for Kehr Process Sewage .... 65
111
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TABLES
No. Page
1 Cumulative BOD5 and TOC Removals 18
2 Comparison of Electroflotation with Sedimentation 33
3 Summary of Costs for 10 mgd Plant 40
A-1 Kehr Process BOD and TOC Data 50
A-II Kehr Process Influent and Effluent Solids Data . . 52
A-III Kehr Process Biological Solids Data 53
A-IV Kehr Process Loading Factors 55
A-V Concentration of TOC and BOD in Filtered and
Unfiltered Samples of Kehr Sewage and Effluent . . 56
A-VI Concentration of Total Phosphate and Organic
Nitrogen in Filtered and Unfiltered Samples of
Kehr Sewage and Effluent 57
A-VII Kehr Process pH Data 58
A-VIII Data for the Electroflotation of Kehr Mixed Liquor 59
A-IX Summary Sheet for Diurnal Variation Study .... 60
A-X Kehr Process Influent and Effluent Phosphate
Concentration 61
A-XI Nitrogen Data for Kehr Process Sewage 62
A-XII Nitrogen Data for Kehr Process Effluent 63
IV
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SECTION I
CONCLUSIONS
The use of the Kehr Activated Sludge Process (KASP) for treatment
of domestic sewage and high strength cannery wastes was successfully
demonstrated. Aerobic digestion was obtained in the aeration tank
of a completely mixed activated sludge plant at aeration times from
2 to 8 hours.
This process does not remove phosphorus or significant quantities
of nitrogen since solids are not intentbnally wasted but appear in the
effluent stream. Although 90 percent 6065 removal can be obtained
for high strength wastes, the effluent would not be satisfactory
for discharge to bodies of water in many areas. Thus, a potential
application of the process is for pretreatment of high strength
industrial wastes prior to discharge to a municipal sewer system.
The KASP has the ability to withstand long periods of little or no
organic loading without a substantial loss of efficiency when loading
is resumed.
It was determined that electroflotation is technically but not economically
feasible for this application. Power costs and costs for electrode
replacement are excessive. Electroflotation may have application for
very small scale treatment systems and for thickening but cannot
compete with sedimentation for large scale systems.
From results of this study, large scale demonstration of the KASP for
pretreatment of high strength industrial wastes prior to discharge
to a municipal sewer system 1s Indicated. Because of the large
differences 1n BOD removal rate constants for various Industrial
wastes, it is considered desirable to operate a pilot plant to deter-
mine design parameters for each waste.
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SECTION II
INTRODUCTION
The activated sludge process is used for treating a variety of
industrial wastes; however, these wastes often cause problems
because of their seasonal nature and their shock loading effect
on a conventional treatment plant by way of sudden high strengths
or flows. Examples of such wastes are cannery, meat packing or
processing, dairy, paper mill, and textile plant effluents.
Adequate processing is needed to overcome such treatment
difficulties.
An adaptation of the activated sludge process that aooears to be
capable of processing high strength wastes has been studied in Europe and
uses high concentrations of mixed liquor suspended solids with little
sludge wasting. This adaptation, which was a parallel development
to extended aeration, is the Totalklaranlage developed by Professor
Dietrich Kehr of the Technishe Hochschule in Hanover, Germany (1) and
consists of an activated sludge with a concentration of mixed liquor
suspended solids of 10,000 to 14,000 mg/liter and aeration time of
6 hours. Kehr has reported high removals of 8005, nitrogen, and
phosphorus with a loading of about 94 pounds of BODs/1000 ft3 of
aeration tank. The high solids concentration of the process when
coupled with physical conditions capable of maintaining a proper
environment comprises an inherent buffering capability for high strength
waste, but at times, also causes operating difficulties in the liquid-
solids separation of the activated sludge in the final tank.
The basic objective of the investigation reported herein was to dem-
onstrate reliable performance of an adaptation of the activated sludge
process using high concentrations of mixed liquor solids. The FMC
Corporation has termed this the "Kehr Activated Sludge Process"
(KASP). This system treated both domestic sewage and cannery wastes
having BODs strengths of 200 to 2000 mg/liter. Flotation for solids
separation and densification as well as gravity sedimentation was
studied to determine processing requirements for application to
full-scale treatment plants.
This report describes the tests conducted to determine the effect-
iveness of the KASP for treating domestic sewage and cannery wastes.
It also includes the cost estimates for a 10 mgd KASP treatment plant
using either gravity sedimentation or electroflotation for solids
separation.
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SECTION III
TEST FACILITY AND EQUIPMENT
Permanent Facility
The permanent facility at FMC's Central Engineering Laboratories (CEL)
Environmental Engineering site includes a 12" diameter inlet sewer
from an 18" diameter sanitary sewer serving part of the City of Santa
Clara. An adjustable hinged gate has been provided in the 18" line
to divert sewage into the test site. A pumping station which receives
the sewage from the 12" line is provided with two parallel open channels
in which various forms of screening and comminution are available.
Any one or all of the two channels and the 12" line may be closed off
and emptied if desired. At the present time, a standard Chicago Pump
comminutor serves one channel and & production prototype Barminutor
machine the other.
All sewage, whether directly from the sewer, screened, or comminuted,
flows into a wet well located beneath the channels and comminuting
equipment. In an adjacent dry well are two centrifugal pumps for
delivering the sewage from the wet well through a six-inch pressure
line to an elevated flow splitter located in an outdoor test area.
Valving in the dry well permits direct pumping back to the city sewer
downstream from the point from which it was withdrawn. Maximum
delivery to the elevated splitter is 750 gpm with both pumps running.
A portion of the total flow to the splitter is diverted to a settling
cone where grit and a portion of the suspended solids are removed.
The overflow from this settling tank flows to another splitter box
where it can be directed to sites throughout the test facility. A
schematic diagram illustrating the CEL facilities is shown in Figure 1.
Experimental Facilities
A schematic drawing of the activated sludge system used for the KASP
study is shown in Figure 2. The primary components of the system
consisted of an aeration tank with a liquid volume of about 120
gallons and a circular sedimentation tank four feet in diameter.
Mixed liquor was pumped from the aeration tank to the final clarifier
by a positive displacement pump driven by a variable speed motor.
The flow rate was controlled by the speed of the motor. The return
sludge was also pumped by a positive displacement pump and the flow
rate was set equal to the settled sewage flow rate by a timer controlling
the percentage of the time the pump was on. A float switch controlled
the settled sewage flow.
A diurnal flow variation was produced by a 24-hour program timer,
which controlled the power to the mixed liquor and return sludge pumps
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FIGURE 1
FLOW DIAGRAM
PERMANENT AMD EXPERIMENTAL FACILITY
KEHR Process Effluent
Excess Sewage
©
0
©
©
©
18" Santa Clara Sewer
12" Supply Sewer
Open Channels (Gates - Screens)
Barminutor Machine
Commlnutor Machine
Sewage Pumps
Flow Splitter (Elevated)
Settling Tank
Splitter Box (Elevated)
Storage
Aeration Tank
Final Tank
Electroflotation Cell
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SETTLED
SEWAGE
(Feed)
/ 3* ^
AERATION TANK
SETTLING TANK
FIGUHE g
KEHR ACTIVATED SLUDGE. PLAHT
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for each 5-minute interval during the day. Flow patterns similar to
that at the San Jose - Santa Clara Water Pollution Control Plant
were produced by controlling the number of 5-minute cycles during
each hour that the pumps were on and off. The diurnal flow patterns
used are shown in Figure 3.
Oxygen was supplied by a blower which pumped air through 4 carbor-
undum diffusers, each 3 inches in diameter and 24 inches long. The
air flow was varied from 16 CFM to 30 CFM to maintain the concentration
of dissolved oxygen in the mixed liquor greater than 2 mg/liter.
The principal equipment used to study the electroflotation of KASP
mixed liquor was the flotation cell shown in Figure 4. Within this
cell, both the gas production required for the separation and the
separation itself took place.
The cell has a central chamber where the gas and mixed liquor were
introduced and a majority of the separation occurred. The gas was
produced by 50 stainless steel electrodes 2" x 3/32" x 15-1/2" that alternated
as cathode and anode. Electrodes were placed at the bottom of the
chamber as shown in Figure 4 and current was supplied by a D.C. power
supply.
Mixed liquor from the KASP aeration tank was pumped through a cross-
shaped distributor above the electrodes by a positive displacement
pump driven by a variable speed motor. The mixed liquor solids
then contacted the rising gas bubbles which could become attached
causing the solids to rise towards the upper liquid surface where
a sludge blanket formed. This sludge blanket was periodically
swept with a vacuum head to remove the floated solids which were
returned to the aeration tank.
The liquid flow was up the center channel from the feed distributor
and then down the side channels. Those solids with attached bubbles
that were washed over into the side channels were able to float free
because of the quiescent conditions in the side channels. The
remainder of the Solids carried over were washed out in the effluent.
The electroflotation system was tested on a portion of the mixed
liquor overflow stream because of its experimental nature whereas
gravity settling was used on the main stream due to its known
reliable performance.
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120
100
f
g
u_
a
80
i r
L.J
<:
u_
to o
LJ
O.
60
.J
CANNERY FLOW
PATTERN
DOMESTIC FLOW
PATTER
FIGURE 3
DIURNAL FLOW PATTERN USED TO
SIMULATE HYDRAULIC FLOW CONDITIONS
AT SAN JOSE - SANTA CLARA
WATER POLLUTION CONTROL PLANT
40
20
II I I I I I I I I I 1 I I I I I I I I I
0600
1200 1800
HOUR OF THE DAY
M
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CONTINUOUS FLOW FLOTATION CELL
FIGURE 4
FEED
EFFLUENT
50 ELECTRODES
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SECTION IV
EXPERIMENTAL PROGRAM
The experimental program was separated into two studies. One was
the study of various aspects of the biological system and the other
was the study and evaluation of electrofloation for the separation
of mixed liquor solids to produce a clear effluent.
Biological System
The study of the biological system included two main parts: a study
of continuous operation of the KASP treating sewages of various
strengths and a study of the response to an artificially imposed shock
loading situation.
Besides these main studies, a tracer washout study to determine whether
the aeration tank was completely mixed, and a study to determine the
diurnal variation of sewage strength were conducted.
Flotation System
The study of the flotation system was conducted to determine the amount
of gas required to effect a given separation. This information could
then be coupled with information on power requirements obtained
previously (2) to develop costs for a full scale plant.
Laboratory Analyses
Analyses used in the evaluation of the KASP and related separation process
were done in accordance with "Standard Methods for the Examination of
Water and Wastewater", Twelfth Edition, and included the following:
Suspended Solids SS
Volatile Suspended Solids VSS
Total Solids TS
Total Volatile Solids TVS
Sludge Volume Index SVI
Five-Day Biological Oxygen Demand 6005
Organic Nitrogen 0-N
Ammonia Nitrogen NH3
Nitrate Nitrogen NOa
Nitrite Nitrogen N02
PH
11
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Analyses for total organic carbon (TOC) were performed using a Beckman
Carbonaceous Analyzer, Laboratory Model, and all total phosphate
analyses utilized a sulfuric acid - nitric acid wet oxidation procedure
followed by Standard Methods for orthophosphate analyses.
12
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SECTION V
EXPERIMENTAL PROCEDURE
Tracer Washout Study
To determine if the KASP aeration tank was completely mixed, a tracer
washout study was performed by first filling the aeration tank with
fresh water. Then a concentrated sodium chloride solution was pumped
into the aeration tank. The effluent was periodically sampled and
the concentration of the chloride was determined as a function of
time. The chloride concentration in the effluent from a completely
mixed tank can be expressed mathematically by the following equation:
Cc Cn
log £ ~_ c =- Dt (1)
Where: Cp = Feed concentration,
CE = Effluent concentration,
Cj = Initial concentration in the system,
D « Tank displacement per unit time, and
t = Time.
Biological System
The KASP was operated at a return sludge rate of 100 percent. This
was accomplished by adjusting the return sludge flow rate to one-half
the flow rate of mixed liquor to the final tank. Since no sludge was
intentionally wasted, the only other control required was to maintain
the flow of air in sufficient quantity to maintain the mixed liquor
dissolved oxygen about 2 mg/liter. Both the sewage and effluent were
sampled every hour during the 8:00 AM to 5:00 PM working day for an
eight-hour composite. The mixed liquor and return sludge were samples
on a grab basis.
A programmed study was conducted to determine the performance of the
high solids activated sludge system under shock loading conditions. This
was designed to simulate shocking caused by a sudden decrease followed
by a sudden increase in sewage strength. The underloading shock was
simulated by changing the feed to the aeration tank from sewage to fresh
water. After 48 hours, the feed to the aeration tank was changed
back to sewage so that an overloading shock occurred. A constant feed
was begun for one week prior to the test to insure that a steady state
condition existed at the start of the test. Grab samples were taken of
mixed liquor, return sludge, final effluent, and the sewage feed.
13
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Flotation System
To evalutate the electro-flotation of the KASP mixed liquor, the EF
cell was first filled with clear water. The power supply was then
turned on and the current between the electrodes set at the desired
value. After the central chamber was filled with a fine mist of
bubbles rising from the electrodes, the mixed liquor pump was started
and set at the desired flow rate. After at least two hydraulic
detention times, the effluent, mixed liquor, and occasionally the
return sludge were sampled. The amperage and the mixed liquor flow
were measured and recorded. After sampling, the conditions were
changed to begin a new run.
14
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SECTION VI
RESULTS
Tracer Washout
The degree of complete mixing of the aeration tank was determined by
adding a sodium chloride solution (3400 mg/liter as Cl") to the aeration
tank at a flow rate of 2.0 gpm, which resulted in a liquid detention
time of 59 minutes. Effluent samples were analyzed for chloride and
these data as well as the theoretical washout curve are plotted in
Figure 5. The observed data points follow the theoretical curve very
closely indicating that the aeration tank was completely mixed.
The data from the tracer washout also demonstrated the ability of a
completely mixed aeration tank to buffer shock loadings as compared
to a plug flow tank. The salt solution fed to the KASP aeration tank
was a hundred times as concentrated as the fresh water initially in the
tank. As the strong salt solution was added, it was immediately dispersed
throughout the aeration tank, which resulted in a gradual increase in the
salt concentration in the aeration tank. The washout data demonstrating
this buffering phenomena are shown graphically in Figure 6. In a plug
flow tank, the hundred-fold increase would not be dispersed throughout
the tank and would move through the tank as a highly concentrated core
of salt water. If a hundred-fold increase occurred in sewage strength,
this same buffering phenomena of the completely mixed aeration tank
would allow the microorganisms in the mixed liquor to react to a slowly
changing environment rather than any sudden shock that would be
experienced in a plug flow tank.
Continuous Operation of KASP
The KASP, as operated at CEL, had no solids removed from the system as
a waste sludge stream. Therefore, the KASP could only remove carbonaceous
matter and nutrients from the liquid waste by converting them to a gaseous
form. Carbon, nitrogen, and phosphorus were the materials measured in
this study and the removal of each of these by the KASP is presented in
the following results.
The KASP was operated continuously for 28 days during the fall of 1967 and
for 12 days during the fall of 1968. Because the canneries did not
usually pack on weekends, the sewage during the canning season was
characterized by high concentrations of BODs from Monday to Friday and
low BODs domestic waste on the weekend. After the canning season, the
sewage, which primarily consisted of domestic waste, had a fairly
constant concentration of BODs throughout the week.
Data showing the performance of the KASP stabilizing organic waste are
15
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o
g
o
LU
UJ
a:
1.0
.9
.8
.7
.6
.5
.4
.3
.2
.1
,09
,08
FIGURE 5
TRACER WASHOUT CURVE FOR THE
KEHR PROCESS AERATION TANK
X ^
^Theoretical
\^> Washout
30 60 90
TIME OF WASHOUT IN MINUTES
120
150
Cp * Feed Concentration
CE « Effluent Concentration
CT * Initial Concentration in Tank Before Test
16
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3,500
3,000
t.
IV
O>
2,500
2,000
o
ii
o
u.
O
1,500
O
§
1 ,000
500
FEED CHLORIDE CONCENTRATION
WASHOl
CURVE
TRACER WASHOUT CURVE
FOR THE KEHR PROCESS
AERATION TANK
AIR FLOW - 20 CFM
LIQUID DETENTION TIME - 59 MIN
60 90
TIME OF WASHOUT IN MINUTES
17
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shown in Figures 7 and 8. Figure 7 shows the TOC data while Figure
8 shows the data for BODs. On weekdays during the canning season,
the KASP treated cannery wastes with concentrations of BOD5 ranging
up to 1550 mg/liter and achieved over 90 percent 8005 removal and
80 percent TOC removal. However, on the weekends the sewage
strength decreased while the concentration in the effluent of both
8005 and TOC remained at about the same level as during the week.
This caused a reduction in the percent removals of both TOC and BOD5
during the weekends. The most illustrative example of this phenomena
was Sunday, September 8, 1968, where the percent removal of 6005
dropped to 28.4 and the percent removal of TOC dropped to -48.4.
This nearly constant effluent quality was due in part to the inverse
of the washout phenomena shown in Figure 6. Another factor that
probably contributed to the nearly constant effluent quality is
that the BODc in the effluent is affected by the efficiency of the
solids separation system which is somewhat independent of the influent
BOD.
During the period when the KASP treated domestic sewage, the influent
and effluent qualities were fairly constant yielding constant per-
cent removals of carbonaceous materials measured as either BOD5 or
TOC. Because of the consistent sewage quality, the only shocking
of the KASP came from the diurnal flow variation programmed into the
system. During one 24-hour period, the biological system was sampled
every hour. Four-hour composites of the feed and effluent were made
up and analyzed for TOC. The results of this test are shown in Figure
9. These data show that the KASP produced a very consistent effluent
by damping out the variation in loading due to flow in a manner similar
to that observed for the organic shocking during the canning season.
Based upon the 8-hour composite samples, the BODs and TOC removals
for each aeration period tested were calculated. The percent removals
were calculated by summing the total amounts of BOD5 and TOC in both
the feed and effluent for each aeration period rather than on a daily
basis. These percent removals are presented in Table 1 along with the
number of days of operation at each aeration period. Detailed test
data are in the appendix.
TABLE 1
CUMULATIVE BOD5 AND TOC REMOVALS
Aeration Cumulative 8005 Cumulative TOC Period of
Period Removal (%) Removal (%) Operation
8 hours 88.9 80.2 11 days
6 hours 84.4 77.2 7 days
4 hours 85.7 77.1 9 days
2 hours 95.3 87.4 11 days
AVERAGE 88.5 80.4
18
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TOC DATA FOR THE KEHR PROCESS
FOR CONTINUOUS OPERATION
~ 800 -
S 600 -
I i i I i
I 1 i i I i i i i I
1 5
September
30
October
10
15
20
* Aeration Time
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KEHR PROCESS BOD DATA
FOR CONTINUOUS OPERATION
August September
* Aeration Time
0 5
October
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300
250
3 200
o
o
150
£
100
50
FIGURE) 9
DIURNAL VARIATION OF
XEHR PROCESS TOC
Effluent
8 N 4
DATE 10/10 and 10/11/68
10/10 fILSS = 11,580
rtVSS = 9,560
8 M 4
HOUR OF THE DAY
8
10/11 MLSS
MVSS
13,230
10,900
2 HOUR AERATION TIME
21
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The operation of the KASP was such that the changes 1n aeration
period coincided with changes in sewage strength and character
resulting from seasonal fluctuations in cannery operation. For
this reason as well as the short period of operation at each aeration
period, the results at different aeration periods cannot be com-
pared directly. However, removals of about 80 and 90 percent for
TOC and BOD5, respectively, do give some indication of the treatment
efficiency of the KASP.
When designing a particular activated sludge treatment plant, one
of the most important design parameters is the loading rate. Three
different loading parameters were calculated from the data for the
operation of the KASP and are given in Table A-4 in the appendix.
The three are: the volumetric loading measured as the pounds of
BODs per day per thousand cubic feet of aeration tank, and two forms
of the organic loading measured as the pounds of BODs per day per
pound of mixed liquor suspended solids, and as the pounds of BODs
per day per pound of mixed liquor volatile suspended solids.
The various loading parameters were not constant due to the lack of
steady state conditions. For the KASP with no intentional sludge
wasting, the observed average loading, excluding weekends, were 200
pounds of BODs per day per thousand cubic feet of aeration tank
capacity, 0.473 pounds of BODs Pe>" day per pound of mixed liquor
volatile suspended solids, and 0.418 pounds of BODs Per day per
pound of mixed liquor suspended solids. For the purpose of this
report, the average volumetric loading was used as the design parameter
for scale up. It should be noted that the mixed liquor suspended
solids were high in volatile matter. They were 85 to 90 percent
volatile matter which is higher than the 75 percent found for many
wastes.
Data on the influent and effluent phosphate and nitrogen are shown
in Tables A-X to A-XII in the appendix.Because the system was sampled
only during the eight-hour working day, balances around the system
could not be made due to diurnal variations in flow and waste strength.
Another factor that would affect balances is the short period of time
the system was operated at each loading condition. It is possible
that the system was not stabilized before loading conditions were
changed.
For operation of the activated sludge process without sludge wasting,
there is no mechanism for phosphorus removal. Some removal of
nitrogen could occur by release of nitrogen gas to the atmosphere.
A complete balance for nitrogen would not be possible without analyzing
the composition of all gases.
A 28-hour sampling program was conducted on the KASP effluent and
sewage in an attempt to provide more complete phosphate and nitrogen
balances around the KASP. Grab samples of sewage and effluent were
taken every hour and made up into four-hour composites. The results
are shown in Figures 10 and 11.
22
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45
40
35
8
CC
o
o
»»
1
8
30
25
20
15
10
DIURNAL VARIATION OF
KEHR PROCESS NITROGEN
MLSS 9,200 ?-15,090
tlVSS 6,860^11,205
2 HOUR AERATION TIME
HOUR OF THE DAY
23
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60
FIGURE 11"
T
DIURNAL VARIATION OF KEHR
PROCESS PHOSPHATE
50
40
o
30
o
o
20
OATE 3/11/68-^3/15/63
MLSS 9,200 ^?- 15,090
MLVSS 6,860^-11,205
2 HOUR AERATION TIME
10
8
8 M 4
HOUR OF THE DAY
8
24
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For both nitrogen and phosphate, the difference between the concentration
in the sewage and that in the effluent decreased through the first
24 hours. Then during the first 4 hours of the second day this
difference increased again. At no time was it possible to complete
a nutrient balance. The apparent removals of nitrogen and phosphate
must be explained by the factors discussed above.
Artificial Shock Loading
To better study the effect of shock loading conditions on the KASP, an
artificial shock loading was imposed on the system. For 48 hours
fresh water was fed to the system and then sewage (BOD5 of 230 and 180
mg/liter) was fed for the following 48 hours. The aeration time was 2
hours. The response of the biological system to the artificial shock
loading as measured by the effluent concentrations of BODs, TOC, and
suspended solids is shown in Figures 12 through 14. During the water
feed, there was a washout of the various constituents from the aeration
tank. The concentrations decreased rapidly and then appeared to level
off. Therefore, due to the washout phenomena, the fresh water feed
improved the effluent quality over that prior to the study.
The concentration of BODs ln tne filtered effluent dropped to nearly
zero (Figure 12) indicating that little biodegradable substrate was
present in solution. Because no food for the bio-mass was present in
solution, the production of new cellular mass was reduced causing cell
death and lysing to predominate over synthesis. The concentrations
of TOC, BODs, and suspended solids in the effluent after they leveled
off probably corresponded to loss in the effluent due to cell lysing.
After the sewage was turned back on, a rapid and immediate increase
was observed in the effluent concentrations of both the BODs and TOC.
This rapid increase was followed by a leveling off of the TOC and
filtered BOD5. The filtered BODs and TOC reached a level nearly the
same as that before the initiation of the water feed while the level
of unfiltered TOC was less than before the water feed. The concentration
of unfiltered BODs decreased after the initial rapid increase. The
sewage feed produced little change in the concentration of suspended
solids.
It is interesting to note that the KASP was able to go without any
organic loading for 48 hours with no apparent loss of treatment
efficiency when the organic load was returned. The KASP seems to be
able to adequately handle wastes of periodic discharge.
The shock loading also had an effect, shown graphically in Figure 15,
on the concentration of nitrogen and phosphate in the effluent. During
the fresh water feed, the concentrations of both decreased rapidly to
a fairly steady state value probably corresponding to the rate of cell
lysing. Upon the initiation of the sewage feed, the concentrations of
both increased rapidly but the concentration of nitrogen soon leveled
off well below the concentration prior to the water feed.
25
-------
c
0)
U-i
U-<
w
01
H
a
o
I
in
UH
o
H
2
g
o
20
EFFLUENT BODg AS A
FUNCTION OF TIME FOR THE
SHOCK LOADING STUDY
DATE 3/11/68-^
MLSS 9,200
MLVSS 6,860
2 HOUR AERATION TIME
15,090
11,205
Unfiltered
Sample
Fresh Water Feed
Sewage Feed
Filtered
Sample
15
10
16
32
U8
80
96
Time in Hours From Initiation of the Study
26
-------
4>
4->
H
M
J3
C
H
3
8
I
FIGURE 13
EFFLUENT SUSPENDED SOLIDS
AS A FUNCTION OF TIME FOR
THE SHOCK LOADING STUDY
DATE 3/11/68 > 3/15/68
HLSS 9 »EOO-^15,090
flVSS 6,860
2 HOUR AERATION TIME
Suspended
Solids
Volatile
Suspended
Solids
Fresh Water Feed
Sewage Feed
16
32
80
96
Time in Hours From Initiation of Stud}
27
-------
60
c
H
o
o
ri
M
2
+j
c
<§
50
~ UO
C
3
u
«
£
30
20
10
FIGURE 14
EFFLUENT TOC AS A
FUNCTION OF TIME FOR THE
SHOCK LOADING STUDY
JATE 3/11/68 * 3/15/68
MLSS 9,200 » 15,090
MLVSS 6,860 » 11,205
2 HOUR AERATION TIME
Fresh Water Feed
16 32
Time in Hours From Initiation of the Study
80
96
28
-------
70
H
H
H
S
S5
B
c
0)
u
I
60
50
30
20
10
EFFLDENT NUTRIENT CONCENTRATION
AS A FUNCTION OF TIME FOR
THE SHOCK LOADING STUDY
Total
Phosphate
3/11/68* 3/15/68
ilSS 9,200 * 15,090
MLVSS 6.860* 11.205
2 HOUR AERATION TIME
Sewage Feed
16 31 U8 6U
Time in Hours From Initiation of the Study
29
80
96
-------
Flotation System
The electroflotation cell was operated from May 31, 1968,to August 6,
1968>on mixed liquors ranging in suspended solids concentrations
from 2,120 to 10,080 mg/liter. Sewages processed by the KASP
during the initial portion of the study were of domestic origin and
during the latter half were primarily cannery waste. The principle
effort was devoted to removal of suspended solids, no attempt was
made to maximize the concentration of solids in the thickened sludge.
The results show, Figure 16, the relationship of the amount of gas
generated per gram of solids to the ratio of influent to effluent
suspended solids.
The plots show that the mathematical model presented in the Appendix
is approximately obeyed. Two curves are shown in this figure. The
upper curve is for mixed liquors that had high sludge volume indexes
and were easy to float while the other curve is for sludges with a low
SVI that were difficult to float.
The mixed liquors that yielded the lower curve were primarily from
cannery waste and appeared to have a small floe size. This meant
more floe particles would be required to make up the same sludge
mass than would be required for larger size particles therefore
more bubble-floe attachments would be required. These extra attachments
require more gas per gram ot solids and therefore, make the sludge
harder to float.
To obtain data for cost estimates for the electroflotation of KASP
mixed liquors, these data were extrapolated to performance corresponding
approximately to gravity sedimentation. Secondary gravity clarification
of KASP mixed liquor containing about 10,000 mg/liter of suspended
solids produced an effluent containing about 20 mg/liter of suspended
solids on domestic sewage and with cannery wastes, the effluent
suspended solids were about 100 mg/liter. Extrapolating the two curves
to the corresponding ratio of influent to effluent solids, the gas
requirements are about 28 cc of gas per gram of solids for either waste.
Although the concentration of the floated solids was not studied, the
floated solids appeared to increase in concentration upon standing.
In one particular case, no sludge was removed from the flotation cell
for 5 hours allowing the sludge blanket to compact and drain. Under
these conditions, the sludge blanket attained a concentration of total
solids of 11 percent. However, in most cases the concentration of
total solids in the return sludge was about 3 percent compared to about 2
percent for gravity sedimentation. Electroflotation provided a denser
sludge so the volume of recycled sludge would be less.
While the EF cell was operating, gravity settling was being used to
handle a majority of the KASP mixed liquor. This provided for a more
30
-------
FIGURE 16
DATA FOR THE ELECTROFLOTATION OF
KEHR PROCESS MIXED LIQUORS
400
300
0200
o
|
w 100
£ 80
c
3
Ul
o
c
0)
60
40
30
o 10
10
A
o
A
x
4-
o
10 15 20
cc OF GAS PRODUCED PER GRAM OF SOLIDS
SVI - 234 - 292
SVI « 50 - 153
31
-------
stable operation of the KASP aeration tank in case of power failures
or other process upsets. Also, parallel operation allowed a comparison
of gravity settling with electroflotation of the same mixed liquor at
similar hydraulic loadings. Table 2 shows the data from parallel
performance.
Electroflotation Costs
Electroflotation has two major costs which must be considered when
evaluating its use for secondary solids separation. These costs are
the operating costs such as power and labor and the capital costs
for such things as tankage and electrodes. The labor and tankage
costs are similar to those for gravity settling and will be discussed
in the section on economic evaluation. However, the power and electrode
costs are unique to electroflotation and will be discussed here.
The power consumed in electroflotation is used primarily to generate
gas bubbles by electrolysis of water. Each coulomb of current passed
between the electrodes generated 0.174 cc of gas. The volume of gas
required per gram of solids to achieve a given separation can be found
experimentally as shown in Figure 16. This information can then be
used to calculate the current required to effect the desired separation.
Since the power is equal to the product of the voltage and the current,
power requirements for electroflotation depend upon the voltage required
to overcome the resistance of the electroflotation cell. This resistance
is the sum of the resistance of the external circuit and the resistance
of the water between the electrodes. The voltage across the external
circuit is relatively constant from cell to cell whereas the voltage
between the electrodes is governed by solution conductivity, electrode
spacing, and the current density or electrode area.
Increasing the current density in the cell increases the cell resistance
and therefore is used as a design parameter. The effects of the mixed
liquor conductivity and the electrode spacing on the relationship
between current density and cell voltage are presented in Figures 17
and 18. Both figures show that electrolysis of water with a lead dioxide
stainless steel electrode system is initiated between 2.8 and 3.0 volts.
Beyond 3 volts, the current density increases linearily with voltage.
The first figure shows that as the conductivity increases, the voltage
required to produce a given current density decreases. Therefore, the
higher the conductivity of the mixed liquor, the lower the power consumption
at a given current density. The second figure shows that as the electrode
spacing decreases, the voltage required to produce a given current
density also decreases. Therefore, the minimum possible electrode spacing
and the highest possible conductivity would require the minimum voltage.
32
-------
TABLE 2
COfPARISON OF ELECTROFLOTATIOII '.IITH SEDIMENTATIOH
Mixed Liquor
Suspended Solids
(tng/liter)
3480
3230
34GO
3955
3785
3360
6470
4675
SVI
258
285
265
234
244
247
147
Electroflotation
Hydraulic Loadino
gal/day-ft2
250
250
250
214
230
800
510
250
gas/solids ratio
cc/n
21.0
19.4
15.4
17.6
17.1
11.6
5.6
15.8
Eff. SS*
20
36
40
26
30
68
574
47
Sedinentaticn
Eff. SS*
20
27
39
17
1'J
19
29
29
Hydraulic Loading
oal/day-ft2
303
298
303
303
298
303
308
322
CO
* Effluent Suspended Solids in mg/liter
-------
30
FIGURE 17
Current Density as a Function of Cell Voltage
-for Different Mixed Liquor Conductivities
25
20
&
15
10
Lead Dioxide Anode
Stainless Steel Cathode
Electrode Spacing 0.225 Inches
5 10 15
Measured Voltage Between Electrodes (Volts)
34
-------
FIGURE 18
Current Density as a Function of Cell
Voltage for Different Electrode Spacing*
Lead Dioxide Anode
Stainless Steel Cathode
Conductivity » 960 pmhos/cm
5 10 15
Measured Voltage Between Electrodes
35
-------
The data presented In Figures 17 and 18 can be expressed mathematically
as:
ID = K a (v-3)
Sn
Where:
ID = Current density in amperes/ft2
K = Constant
g = Conductivity in y mhos/cm
V = Voltage in volts
S = Electrode spacing in inches
n = Constant - 0.9
For this report 0.225 inches was considered the minimum reasonable spacing
because a lesser spacing would lead to undue clogging due to solids from
the mixed liquor and deposits, mainly calcium carbonate, that form on
the cathodes.
For a given liquor to be separated, the voltage and therefore the power
cost will decrease as the current denisty is decreased. However, the
electrode area required will increase as the current density is decreased
thus increasing the electrode costs. Hence, there must be an optimum
current density that will balance the cost of generating the gas bubbles
with the capital cost of the electrodes.
If the operating labor, the tankage cost, and the external circuit power
requirements are assumed to depend only upon the solids loading, then
only the electrode costs and the intra-electrode power costs are a function
of the current density. Both the daily electrode cost based upon $7.00
per square foot for a 10 mgd plant and a life of 1000 days and the daily
power cost, based upon 1000 amperes, are plotted as a function of current
density in Figure 19. This figure also shows the sum of these two costs.
The optimum current density is about 8 amps/square foot yielding a cost
of $2.50 per day for 1000 amperes. However, the daily cost from 6 to 10
amperes per square foot is less than $2.60 for 1000 amperes showing the
total costs to be fairly insensitive to current density near the optimum.
36
-------
$6.00
$5.00
$4.00
$3.00
5S
0
to
o
$2.00
$1.00
Daily Power and Anode Costs
For Electroflotation as a
Function of Current Density
1000 Amperes Current
$0.01 per KWH
$7.00 per ft.2 of Anode
0.225 1n. Electrode Spac Ing
1000 w mhos/cm Conductiyity
Plant* 10 mod
8 12 16
CURRENT DENSITY (Anpere/ft.2)
37
-------
SECTION VII
ECONOMIC EVALUATION
The final evaluation of any sewage treatment process is whether
the cost of that particular process is competitive with other forms
of treatment. For this reason, cost estimates for a 10 mgd treatment
plant using the KASP were prepared for both electroflotation and
gravity settling. These cost estimates are exclusive of primary
treatment because the cost of primary treatment varies considerably
for different industrial wastes.
Most of the unit costs used were those presented by Smith (4). The
main design parameters used were 200 pounds of BOD per day per thousand
cubic feet of aeration tank, 40 pounds of mixed liquor solids per day
per square foot of final tank and an oxygen transfer efficiency of 15 percent
at zero dissolved oxygen. Also, it was assumed that the above volumetric
loading would produce a concentration of mixed liquor suspended solids
of 10,000 mg per liter.
Table 3 shows a breakdown of capital, operating, and total annual costs for
gravity sedimentation and flotation. A comparison shows that gravity
settling requires a higher capital outlay than does treatment by electro-
flotation. It should be noted that the expense of the electrodes is
treated not as a capital cost but, because of their short life, as an
operating expense.
Electroflotation was assumed to have the same operating and maintenance
costs as gravity settling for aeration, sludge collection, pumping, etc.
However, electroflotation has the additional costs for power and electrodes.
The added cost for these is $2,430 per day or about 20tf per thousand
gallons. This corresponds to a cost of $4.40 per ton of floated solids
comparing favorably to the $6 to $15 per ton of floated solids that has
been reported (5) for air flotation.
As can be seen in Table 3, the operating costs using electroflotation
are about three and a half times larger than those using gravity settling
and are excessive. The operating cost for the KASP using gravity settling
and treating a sewage containing 250 mg/liter of BOD is about 7t per
thousand gallons compared to 29tf for electrofloatation. It should be noted
that because of the mode of operation for the KASP, these costs include
the handling of waste activated sludge.
39
-------
TABLE 3
SUMMARY OF COSTS FOR 10 M6D PLANT
CAPITAL COST * ($ x 103)
BOD BOD BOD BOD
250 mg/1 500 mg/1 750 mg/1 1000 mg/1
Gravity Sedlmenta- 2,474 2,875 3,274 3,679
tlon
Electroflotatlon 1,901 2,302 2,702 3,106
OPERATING COST $/1000 GALLON **
BOD BOD BOD BOD
250 mg/1 500 mg/1 750 mg/1 1000 mg/1
Gravity Sedlmenta- 2.2 3.2 4.2 5.1
tlon
Electroflotatlon 25.7 26.6 27.6 28.6
TOTAL ANNUAL COST tf/1000 Gallon ***
BOD BOD BOD BOD
250 mg/1 500 mg/1 750 mg/1 1000 mg/1
Gravity Sedimenta-
tion 6.7 8.4 10.0 11.5
Electroflotatlon 29.1 30.8 32.4 34.0
* Costs are for 1967
** Based on Itf/KWH
*** Based on 4-1/2% Interest and 25-year Hfe
40
-------
SECTION vrn
DISCUSSION
The operation of the KASP biological system using gravity settling was very
effective in BOD5 and solids removal and performed with no major difficulties
Once the air and liquid flows were set, the system required no attention
except for sampling and mechanical maintenance. The biological system
performed well throughout its operation except for the period of July 9th
through July llth, 1968 when the pH of the sewage ranged from 9.2 to 11.2.
This high pH waste raised the pH of the mixed liquor to 9.7, which
apparently killed most of the mixed liquor bio-mass because little or
no active microbiological life was observed by microscopic examination.
The electroflotation system also performed well but was susceptible to power
failures. On those occasions when a power failure occurred, gas was no longer
generated at the electrodes and the flotation cell would fill with mixed
liquor solids. When the power was returned to the electrodes, the sludge
around the electrodes seemed to be so dense that these solids would not float.
To resume operation, these settled solids had to be drained from the bottom
of the flotation cell. Because of this apparent susceptibility to power
failures, as well as the higher operational cost, electroflotation seems
to be better suited to sludge concentration or some other use where such failure
does not directly affect effluent quality.
The operation of the KASP showed that aerobic digestion could be obtained
in the aeration tank of a completely mixed activated sludge plant at aeration
times from 2 to 8 hours. This was done by having no Intentional wasting
of sludge and operating such that the concentration of mixed liquor solids
stabilized at about 10,000 mg/Hter. The KASP produced about a 90 percent
reduction in BOD5 but the KASP does have features that can limit Us
application.
One limitation is the low removal of TOC. Organic carbon is present in the
raw waste in two forms, non-biodegradable carbon and biodegradable carbon.
Non-biodegradable caron is unaffected by microbiological activity and
therefore would not be removed by the KASP or any other activated sludge
process. This portion of the organic waste will pass through unchanged
and therefore limit the amount of carbon that can be removed from the
influent waste. In the KASP, most of the biodegradable carbon, measured
as BOD5, was readily converted to a settleable activated sludge mass
and carbon dioxide allowing high removals of BOD5. However, a portion
of the settleablesludge mass cannot be biodegraded. Therefore, it cannot
be oxidized and removed as carbon dioxide. In conventional activated
sludge treatment, some of this non-biodegradable sludge is removed as
waste activated sludge. The KASP differed from conventional activated sludge
treatment in that no solids were Intentionally wasted from the system.
Therefore, the non-biodegradable sludge mass formed by the KASP must
either remain in the aeration tank or be washed out as organic carbon
in the effluent. McKinney (6) Indicates that for complete oxidation
systems, approximately 10 to 13 percent of the biodegradable organic matter
being treated will appear in the effluent as inert sol Ids. For the
operation of the KASP, the removal of organic carbon was usually about
41
-------
80 to 85 percent. The effluent from the KASP was high in turbidity and
color and did not have the sparkling appearance that is observed in the
effluent from a well run activated sludge plant that wastes activated
sludge. The increase in color and turbidity over a conventional activated
sludge plant is probably due to the added carbon carried into the effluent.
Because no waste activated sludge stream is removed from the KASP, no
inorganic nutrients are removed with the waste sludge. However, in a
conventional activated sludge plant inorganic nutrients are removed
with waste activated sludge. Therefore, BOD removal is the only area
where the KASP can equal the performance of an activated sludge plant
that wastes sludge.
One logical extension of the KASP is increasing the volumetric BODs loading
and thereby increasing the substrate level and correspondingly the
concentration of mixed liquor solids. The increased loading results
in a smaller aeration tank and reduced costs. However, the BODs
loading can only be increased if there is sufficient aeration capacity
to supply the increased oxygen demand that the increased loading would
require. Therefore, the BOD loading and the steady state concentration
of solids in the mixed liquor are limited by the aeration capacity.
For this study, 10,000 mg/liter was thought to be a good compromise.
The KASP provides a lower removal of TOC, nitrogen, and phosphorus
than can be achieved from a conventional activated sludge plant that
wastes sludge, but the KASP offers other advantages. The KASP was found
to be able to produce a high degree of treatment of sewage following 48
hours with no organic loading.
One possible use of the KASP that will profit from its advantages and
not be hindered by its disadvantages is the treatment of high strength
industrial wastes prior to their discharge into a municipal sewer.
The municipal treatment plant would benefit from the reduction in BODs.
Some of the advantages of the KASP that the industry could benefit from
are given below.
The KASP provides simple operation requiring no waste sludge handling
facilities. The KASP has the ability to withstand long periods of no
organic loading for industries that do not work over weekends or do not
have 24-hour a day production.
One last advantage of using the KASP for waste treatment at an industrial
plant prior to discharge of the waste into a municipal sewer is that the
cost of treatment could possibly be less than that given in this report
since some forms of treatment such as preliminary treatment and
chlorination could be eliminated because of the duplication of services
at the municipal treatment plant.
The KASP appears to be a suitable form of waste treatment where about 90
percent removal of BOD5 1s desired and where little removal of either
phosphorus or nitrogen, as well as only an 80 percent removal of organic
carbon, 1s acceptable. For a waste containing 250 mg/liter of 6005, the
KASP using gravity settling can meet these requirements at an estimated
42
-------
cost of 7
-------
SECTION IX
ACKNOWLEDGMENT
The continuing attention, Interest, and technical review and guidance
of this work by Mr. Charles L. Swanson, as FWQA Project Officer,
1s gratefully acknowledged.
Contributing Personnel Included Warren G. Palmer, M. Floyd Hobbs, James
M. Rowe, Sllvestre W. Sierra, and Frank F. Sako.
Appreciation 1s expressed also to Dr. H. S. Smith for his Interest 1n
the project.
45
-------
SECTION X
REFERENCES
1. Kehr, Dietrich, "Aerobic Sludge Stabilization in Sewage Treatment
Plants," Third International Conference on Water Pollution
Research, Section 11, Paper No. 8, Conference Center, Messegelande
Theresienhohe, Munich, Germany.
2. Palmer, Warren, "Separation of Sewage Solids by Flotation," Internal
FMC Corporation, Report, August 25, 1967.
3. Smith, H. S., and Paulson, Wayne L., "Homogeneous Activated Sludge,"
Civil Engineering "36, 56, May, 1966.
4. Smith, Robert, "Cost of Conventional and Advance Treatment of Wastewater,
"Journal Water Pollution Control Federation" 40_, 1546, September, 1968.
5. Burd, R. S., "A Study of Sludge Handling and Disposal," U. S. Department
of the Interior, FWPCA - Publication No. WP-20-4.
6. McKinney, Ross E., "Microbiology for Sanitary Engineers, "McGraw-Hill
Book Company, Inc., New York, 1962.
7. Vrablik, Edward R., "Fundamental Principles of Dissolved-Air Flotation
of Industrial Wastes, "Proceedings of the Fourteenth Industrial Waste
Conference, Purdue University Engineering Extension Series, No. 104,
1959.
47
-------
SECTION XI
APPENDICES
Kehr Process Operational Data
49
-------
TABLE A-I
KEHR PROCESS BOD AMD TOC DATA
Date
8/29/68
8/30/68
8/31/68*
9/1/68**
9/2/68***
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68*
9/8/68**
9/9/68
9/22/67
9/23/67*
9/24/67**
9/25/67
9/26/67
9/27/67
9/28/67
9/29/67
9/30/67*
10/1/67**
10/2/67
10/3/67
10/4/67
10/5/67
Aeration
Period
8 hours
n
H
N
H
N
II
6 hours
n
n
n
n
n
H
4 hours
it
it
n
n
it
ii
Sewage
TOC (mg/1)
764
820
580
190
114
718
825
882
840
560
78
690
483
160
81
470
477
509
316
329
161
88
210
280
200
225
Effluent
TOC (mg/1)
121
127
80
120
113
76
129
130
141
145
115
103
82
63
73
82
82
70
118
90
58
39
73
18
43
19
% TOC
Removal
84.2
84.5
86.2
36.8
0.7
89.4
84.4
85.3
83.2
74.2
(-48.4)
85.1
83.0
60.6
9.8
82.5
82.8
86.0
62.6
72.6
63.9
55.6
65.2
93.5
78.5
91.3
Sewage
BOD.; (mg/1)
1233
1545
1113
327
181
1224
1248
1380
1191
888
146
1098
855
345
144
552
801
1038
558
540
177
136
425
330
297
Effluent
BODq (mq/1)
121
94
85
182
97
58
81
100
156
140
104
67
_.
.-
««
107
141
134
66
30
3
37
17
% BOD5
Removal
90.2
93.9
92.3
44.5
56.2
95.2
93.5
91.7
86.7
84.2
28.4
93.9
..
.-
--
89.7
74.7
75.2
62.7
78.0
99.3
88.8
94.3
in
**
Saturday
Sunday
Labor Day
-------
TABLE A-I (Continued)
KEHR PROCESS BOD AND TOC DATA
Date
10/6/67
10/7/67*
10/8/67**
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67*
10/15/67**
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Period
4 hours
n
M
n
2 hours
H
II
II
II
II
II
II
II
II
Sewage
TOC (mq/1)
246
165
75
180
207
117
142
160
132
108
230
118
127
162
Effluent
TOC (mg/1)
61
42
24
28
27
16
18
18
16
17
26
21
18
12
% TOC
Removal
75.2
74.5
68.5
84.4
86.7
86.2
87.4
88.6
87.8
84.3
88.9
82.0
86.1
92.6
Sewage
BOD5 (mg/1)
333
179
110
127
301
197
223
224
201
166
387
208
209
206
Effluent
BOD5 (mg/1)
45
40
15
18
12
10
13
9
8
5
24
10
7
11
% BOD5
Removal
86.5
77.7
86.4
86.1
96.0
94.7
89.9
95.9
95.9
97.3
93.8
95.1
96.5
94.5
* Saturday
** Sunday
-------
TABLE A-11
KEHR PROCESS INFLUENT
AND EFFLUENT SOLIDS DATA
Date
8/29/68
8/30/68
8/31/68*
9/1/68**
9/2/68***
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68*
9/8/68**
9/9/68
9/22/68
9/23/68*
9/24/68**
9/25/68
9/26/68
9/27/68
9/28/68
9/29/68
9/30/68*
10/1/68**
10/2/68
10/3/68
10/4/68
10/5/68
10/6/68
10/7/68*
10/8/68**
10/9/68
10/10/68
10/11/68
10/12/68
10/13/68
10/14/68*
10/15/68**
10/16/68
10/17/68
10/18/68
10/19/68
Aeration
Pe ri od
8 hours
ii
H
n
n
n
n
n
n
n
n
n
6 hours
n
n
M
n
n
ii
4 hours
n
n
n
n
n
n
n
n
n
n
2 hours
n
n
H
n
n
n
n
n
n
SEWA
SS
(mg/1 )
266
230
234
234
170
206
292
384
320
136
80
218
216
114
103
83
252
262
154
106
124
82
132
116
150
153
125
105
no
169
138
143
153
126
135
147
174
109
118
187
GE
VSS
(mg/1 )
218
169
194
196
125
172
249
316
269
116
63
160
157
98
85
71
200
236
128
101
100
66
124
95
120
110
88
75
99
125
108
98
103
75
103
121
129
78
80
138
EFFL
SS
(mfl/1)
90
88
51
66
143
132
166
144
212
210
192
136
76
38
24
45
48
54
72
70
40
25
58
17
37
19
52
27
18
27
27
21
30
15
12
13
23
24
12
10
ENT
VSS
(mq/1 )
82
82
51
57
115
94
151
124
184
194
162
118
74
35
20
37
39
50
64
51
31
23
44
13
36
18
43
22
17
24
24
18
25
12
9
11
21
20
11
7
* Saturday
% Removal
of SS
66.2
61.7
78.2
71.8
15.9
35.9
43.2
62.5
33.8
(-54.4)
(-140.0)
37.6
64.8
66.7
76.7
45.8
81.0
79.4
53.2
33.6
67.7
69.5
56.1
****
85.3
75.3
87.6
58.4
74.3
83.6
84.0
80.4
85.3
wv w
80.4
WW 4 T^
88.1
91.1
r t 1
91.2
86.8
78.0
89.8
94.6
** Sunday SS . Suspended Sol Ids
*** Labor Day VSS Volatile Suspended Solids
52
-------
TABLE A-III
KEHR PROCESS BIOLOGICAL SOLIDS DATA
Date
8/29/68
8/30/68
8/31/68**
9/1/68***
9/2/68****
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68**
9/8/68***
9/9/68
9/22/67
9/23/67**
9/24/67***
9/25/67
9/26/67
* w «"/ ^"
9/27/67
9/28/67
9/29/67
9/30/67**
10/1/67***
10/2/67
w / / ^
10/3/67
10/4/67
Aeration
Period
8 hours
n
ii
n
n
n
ii
n
H
n
n
H
6 hours
n
n
n
n
n
n
n
n
n
n
n
ii
MIXED LIQUOR SOLIDS DATA RETURN SLUDGE SOLIDS DATA
SS*
12,190
10,930
7,360
7,090
5,750
7,380
7,200
6,030
6,070
5,080
4,400
6,220
11,770
11,300
4,540
8.590
10,360
5,520
5,810
7,300
4,950
4,940
6,814
6,150
8,110
VSS*
11,150
9,720
6,660
6,440
4,380
6,660
6,450
5,390
5,440
4,580
3,980
5,580
«»M
10,640
4,105
7.800
9,395
5,000
5,290
6,620
4,765
4,430
6,115
5,495
7,245
SVI
882
91
133
140
174
135
138
165
164
196
226
160
85
88
116
97
174
165
136
198
198
145
159
123
SS*
26,600
9,840
22,880
23,350
9,530
11 ,750
7,760
6.340
9,740
11,175
4,630
17,520
__
6,990
5,170
18,140
27,970
--
5,310
5,990
10,920
9,300
13,860
VSS*
23,940
8,740
20,630
21,690
8,600
10,470
6,980
5.690
8,750
9,875
4,180
15,670
__
6,570
4,675
16,595
25,110
M
4,080
5,340
9,845
8,270
12,510
TS
__
--
--
--
--
-
1.372%
0.7775%
«
--
0.837%
--
1.127%
0.5848%
0.604%
--
0.881%
* *
TVS
__
«
--
~~
1.256%
0.7162%
--
0.713%
--
1.004%
0.510%
0.520%
0.768%
, , ::, ._
en
CO
* Values are given in mg/liter
** Saturday
*** Sunday
**** Labor Day
-------
TABLE A-III (Continued)
KEHR PROCESS BIOLOGICAL SOLIDS DATA
Date
10/5/67
10/6/67
10/7/67**
10/8/67***
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67**
10/15/67***
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Period
4 hours
H
it
H
H
2 hours
H
H
H
H
H
H
H
H
H
MIXED LIQUOR SOLIDS DATA RETURN SLUDGE SOLIDS DATA
SS*
7,860
4,280
9,120
6,875
6,040
9,310
5,315
9,545
8,610
9,275
9,765
7,595
8,115
3,830
8,850
VSS*
6,340
3,800
8,185
6,040
5,270
8,100
4,675
8,350
7,425
8,005
8,385
6,490
6,930
3,225
7,505
SVI
126
225
109
144
163
107
183
105
115
107
102
130
121
227
112
SS*
8,760
7,540
9,760
11,740
12,070
17,905
10,230
22,830
18,160
30,900
34,420
14,755
18,835
19,860
33,580
VSS*
7,860
6,705
8,680
10,420
10,555
15,925
8,990
20,095
15,890
28,600
32,050
12,685
16,260
17,120
30,710
TS
0.8937%
0.9975%
~
--
TVS
0.7680%
0.8814%
--
tn
Values are given mg/liter
Saturday
*** Sunday
**
-------
TABLE A-IV
KEHR PROCESS LOADING FACTORS
Date
8/29/68
8/30/68
8/31/68*
9/1/68**
9/2/68***
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68*
9/8/68**
9/9/68
9/22/67
9/23/67*
9/24/67**
9/25/67
9/26/67
9/27/67
9/28/67
9/29/67
9/30/67*
10/1/67**
10/2/67
10/3/67
10/4/67
10/5/67
10/6/67
10/7/67*
10/8/67**
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67*
10/15/67**
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Period
8 hours
ii
H
H
H
H
H
n
H
n
H
n
6 hours
n
n
n
H
n
n
4 hours
n
n
n
n
n
n
n
n
n
n
2 hours
n
n
n
n
M
n
n
M
n
#BOD
^S-Day
.303
.424
.460
.138
.094
.498
.520
.686
.588
.524
.099
.530
.290
.122
.127
.257
.309
.752
.384
.444
.214
.165
-
.414
.244
.227
.467
.118
.096
.126
.387
.445
.280
.312
.260
.204
.611
.308
.655
.278
#BOD
MSS-Dav
.332
.477
.509
.152
.130
.556
.580
.768
.656
.582
.110
.590
.321
.129
.140
.283
.340
.830
.422
.489
.223
.184
_
.464
.273
.281
.526
.131
.109
.144
.446
.505
.320
.361
.301
.236
.716
.360
.778
.329
IBOD
10Jft -Day
230
289
211
61
34
229
233
258
223
166
27
205
214
86
36
138
200
260
140
202
66
51
159
124
111
125
67
41
476
226
148
167
168
151
124
290
156
157
155
**
***
Mote
Saturday
Sunday
Labor Day
: Pounds of BOD are #BOD5 fed per day.
are for the aeration tank only.
Pounds of solids and volumes
55
-------
TABLE A-V
CONCENTRATION OF TOC AND BOD5 IN
FILTERED* AND UNFILTERED SAMPLES
OF KEHR SEWAGE AND EFFLUENT
SEWAGE
Date
9/1/68
9/4/68
9/5/68
9/6/68
9/7/68
9/8/68
9/9/68
Filtered* TOC
(mq/liter)
134
730
865
665
500
54
590
Unfiltered TOC
(mq/liter)
190
825
882
840
560
78
690
Filtered* BODr
(mg/ liter) 3
270
1131
1152
1122
759
97
948
Unfiltered BOD,
(mq/liter) b
327
1248
1380
1191
888
146
1098
EFFLUENT
9/1/68
9/4/68
9/5/68
9/6/68
9/7/68
9/8/68
9/9/68
96
48
80
65
70
38
44
120
129
130
141
145
115
103
160
51
96
88
119
45
49
1.82
81
100
156
140
104
67
* Samples filtered through Whatman GFC Glass Filter Paper.
-------
TABLE A-VI
CONCENTRATION OF TOTAL PHOSPHATE AND ORGANIC
NITROGEN IN FILTERED* AND UNFILTERED SAMPLES
OF KEHR SEWAGE AND EFFLUENT
SEWAGE
Date
8/28/68
8/29/68
9/4/68
9/8/68
Filtered* P04
Img/ liter)
25.8
23.7
56.2
Unfiltered P04
(mq/liter)
54.0
--
31.1
58.9
Filtered*
Organic Nitrogan
(mg/ liter)
11.4
10.8
13.0
Unfiltered
Organic Nitrooen
(mq/liter)
21.5
18.6
19.5
--
EFFLUENT
8/29/68
9/4/68
9/8/68
--
22.0
21.8
--
26.1
29.7
2.1
2,3
--
9.0
10.5
* Samples filtered through Whatman GFC Glass Filter Paper
57
-------
TABLE A-VII
KEHR PROCESS pH DATA
Date
8/29/68
8/30/68
8/31/68
9/1/68
9/2/68
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68
9/8/68
9/9/68
Time
AM
PM
AM
PM
AM
AM
AM
PM
AM
PM
AM
PM
AM
PM
AM
PM
AM
AM
AM
PM
pH of The
Sewage
9.00
8.50
8.73
8.40
8.28
7.10
7.82
7.32
9.35
9.25
8.67
9.63
9.12
9.09
9.31
8.89
8.00
7.40
9.02
9.02
pH of The
Mixed Liquor
7.09
7.30
7.69
7.50
7.58
7.00
7.71
7.20
7.70
7.52
7.50
8.00
7.60
pH of The
Effluent
7.11
7.03
7.30
7.22
7.27
6.90
7.02
7.10
7.23
7.21
7.20
7.11
6.78
7.03
7.30
6.88
6.70
7.15
7.12
7.02
58
-------
TABLE A-VI11
DATA FOR THE CLECTKOFLCTATIGIi OF KEiiR MIXED LI^UCR
Run [Jo.
1
2
3
4
5
r
o
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
MLSS
3,555
3,535
3,435
3,425
3,170
3,375
3,480
3,230
3,463
3,955
3,785
3,360
6,470
4,675
3,310
3,210
2,120
4,300
3,020
8,250
5,450
5,400
5.193
10,080
8,370
6,480
7,320
SVI
241
241
247
251
281
292
258
285
265
234
244
247
147
195
___
30
88
51
112
123
132
148
118
100
___
153
134
Electrode Current
(ams)
10
10
3.5
4.7
n
O
5.4
10
8.6
7.3
O
O
8
10
10
10
7.4
10
10
3.8
10.5
10.5
10
9.4
10.5
9. '3
9.9
9.3
10.2
i'ixed Li-'iuor now
1/nin
1.43
1.54
1.44
1 . 43
1.43
1.33
1.43
1.43
1.43
1.20
1.23
4.50
2.36
1.41
1.41
1.23
3.53
2.00
1.73
1.21
0.95
0.96
1.52
0.38
1.13
3.84
1.76
Ratio of :iLSS
Tr Effluent SS
13C
233
111
75
17,1
173
172
36
113
150
121
49
11
100
61
32
16
3
20
33
33
57
24
44
o
LI
43
11
cc of Gas F reduced
;ier <"ran of .'IL52 *
ZJ.G
U.2
17. C
J.7
10 01
u. o
T> o
1 tJ . i->
21.3
19.4
15.4
17.6
17.1
11.6
5.6
15.8
14.0
25.5
14.0
13.7
23.4
11.0
20.1
18.7
13.3
11.7
10.9
17.3
8.2
en
Based upon 10.43 cc/rn'n for 1 anpere.
-------
TABLE A-IX
SUMMARY SHEET FOR DIURNAL VARIATION STUDY
Date Time
8-22-67 12-4 AM
" 4- 8 AM
11 8-12 AM
" 12-4 PM
" 4-8 PM
" 8-12 PM
8-23-67 12-4 AM
" 4-8 AM
" 8-12 AM
" 12-4 PM
" 4-8 PM
" 8-12 PM
8-24-67 12-4 AM
11 4-8 AM
11 8-12 AM
" 12-4 PM
" 4-8 PM
" 8-12 PM
SS
260
104
60
148
144
268
280
84
200
138
140
218
318
171
70
206
248
470
vss
236
94
60
130
119
236
246
68
75
102
114
178
274
56
58
172
208
417
COD
2540
1260
1090
1845
2270
2235
2130
914
1121
1495
1470
1840
2040
812
1062
1493
1866
2098
BOD
1899
969
1104
1152
1119
1359
1572
675
750
843
822
1083
1119
435
603
912
1143
1548
PO^
19.8
15.0
17.4
29.5
25.6
21.5
16.6
10.0
18.0
27.0
23.1
22.7
26.4
20.2
19.7
26.7
28.6
33.3
NO,*
3.90
3.53
3.70
1.25
1.00
1.05
1.45
1.20
1.35
1.45
1.05
1.05
1.00
1.25
1.55
1.70
1.15
1.15
N0?*
- 0
- 0
0
0
. o
.0058
0
.026
- 0
0
0
0
0
.0060
0
.0072
' 0
.0012
0
NHo*
5.53
1.60
9.84
6.99
5.97
6.99
2.91
3.61
9.26
5.10
4.08
9.09
3.09
1.92
4.37
7.43
6.26
16.31
0 - N
23.15
12.38
15.75
17.06
15.58
19.80
18.23
7.57
12.23
13.31
14.04
16.44
20.61
10. J9
12.81
13.98
16.60
37.27
TOC
908
508
421
632
568.4
725.9
727.2
319.5
393
521
510
627
674
276
343
542
585
769
NOTE: All Values are in mg/liter.
* Values given as mg/liter of N
-------
TABLE A-X
KEHR PROCESS INFLUENT AND
EFFLUENT PHOSPHATE CONCENTRATIONS
Date
8/29/68
8/30/68
8/31/68**
9/1/68***
9/2/68****
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68**
9/8/68***
9/9/68
9/22/67
9/23/67**
9/24/67***
9/25/67
9/26/67
9/27/67
9/28/67
9/29/67
9/30/67**
10/1/67***
10/2/67
10/3/67
10/4/67
10/5/67
10/6/67
10/7/67**
10/8/67***
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67**
10/15/67***
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Perl od
8 hours
H
H
ii
it
H
H
H
H
H
H
II
6 hours
H
H
H
II
II
II
4 hours
M
n
H
n
n
n
n
n
n
n
2 hours
n
M
n
n
n
n
n
H
II
Total Concentration of Phosphate in mg/liter*
Sewage
19.2
58.0
41.8
50.7
44.4
31.1
32.0
26.0
20.5
58.9
41.1
28.6
35.8
26.6
24.8
20.6
23.4
42.4
50.0
57.2
23.8
54.2
51.2
30.2
33.4
40.4
77.6
22.6
38.0
28.6
23.4
29.4
27.4
28.6
29.2
29.2
28.6
28.8
27.2
Effluent
14.2
18.5
18.5
23.0
36.4
35.3
26.1
19.9
27.0
17.5
29.7
24.4
14.2
11.6
21.8
23.8
17.6
18.4
28.6
32.6
29.4
26.4
51.4
10.8
36.6
21.6
25.2
32.6
31.0
30.6
25.6
23.6
22.4
30.2
27.2
26.2
29,4
25.2
28.8
23.8
* As P04
** Saturday
*** Sunday
**** Labor Day
61
-------
TABLE A-XI
NITROGEN DATA FOR KEHR PROCESS SEWAGE
Date
8/29/68
8/30/68
8/31/68**
9/1/68***
9/2/68****
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68**
9/8/68***
9/9/68
9/22/67
9/23/67**
9/24/67***
9/25/67
9/26/67
9/27/67
9/28/67
9/29/67
9/30/67**
10/1/67***
10/2/67
10/3/67
10/4/67
10/5/67
10/6/67
10/7/67**
10/8/67***
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67**
10/15/67***
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Pe rl od
8 hours
M
H
it
ii
H
ii
ii
M
ii
ii
it
6 hours
ii
ii
H
ii
H
n
4 hours
n
M
n
n
n
n
H
II
II
II
2 hours
n
n
n
n
H
n
n
n
n
Nth*
6.65
4.60
5.36
5.65
28.00
9.30
7.57
6.41
6.70
6.99
6.99
8.30
7.0
9.3
29.9
14.1
8.6
6.9
10.0
12.0
24.4
27.5
18.1
14.6
15.6
16.0
17.2
23.0
32.2
34.4
21.9
20.3
20.6
15.6
24.0
108.2
21.6
15/3
14.3
19.7
Orqanic-N*
18.60
16.80
15.10
10.90
15.10
20.70
19.50
--
21.30
13.10
6.41
17.80
13.1
12.1
11.1
13.6
16.6
16.2
10.1
10.1
10.8
10.2
8.9
11.1
7.5
9.8
11.3
10.0
10.7
9.1
11.3
10.3
13.0
3.8
10.3
9.6
6.4
11.1
10.5
11.1
NO?*
M M
mm
--
--
--
«,
..
--
mm
--
__
«
__
--
__
--
._
mm
mm
mm
mm
.01
.01
Trace
__
Trace
Trace
__
Trace
..
__
--
N(h*
1.35
0.88
1.10
0.72
0.38
0.50
0.28
2.36
1.54
1.55
1.15
0.95
1.00
_-
..
0.98
0.96
0.82
0.54
0.85
0.18
0.08
mm
__
__
__
mm
mm
mm
0.16
..
0.19
0.78
0.13
__
1.36
0.92
0.92
0.92
Total N*
26.60
22.28
21.56
17.27
43.48
30.50
27.35
_-
29.54
21.64
13.09
27.05
21.10
21.40
41.00
26.68
28.68
23.92
20.64
22.95
35.38
37.78
27.00
25.70
23.10
25.80
28.50
33.00
42.90
43.51
33.37
30.60
33.79
20.18
34.43
117.80
33.62
27.32
25.72
31.72
* Values given are in mg/liter as Nitrogen
** Saturday
*** Sunday
**** Labor Day
62
-------
TABLE A-XII
NITROGEN DATA FOR KEHR PROCESS EFFLUENT
Date
8/29/68
8/30/68
8/31/68**
9/1/68***
9/2/68****
9/3/68
9/4/68
9/5/68
9/6/68
9/7/68**
9/8/68***
9/9/68
9/22/67
9/23/67**
9/24/67***
9/25/67
9/26/67
9/27/67
9/28/67
9/29/67
9/30/67**
10/1/67***
10/2/67
10/3/67
10/4/67
10/5/67
10/6/67
Aeration
Period
8 hours
M
ii
n
it
n
n
n
ii
n
n
n
6 hours
ii
ti
n
n
ii
ii
4 hours
n
n
n
n
ii
n
n
NH3*
^
--
_-
--
--
_-
--
»
0.5
1.2
2.3
9.8
4.8
2.8
3.1
2.0
1.2
11.7
15.7
7.0
4.4
10.3
11.6
Organic-N*
9.04
7.05
10.00
5.45
12.20
8.40
10.50
--
11.07
10.77
9.61
8.90
7.2
5.4
4.3
4.0
5.2
5.2
5.9
6.4
4.2
3.5
5.2
2.3
4.2
2.0
5.4
N02*
__
__
__
__
_-
--
__
__
__
.-
--
_-
-.
--
__
_.
.-
_ _
Trace
Trace
Trace
Trace
Trace
N03*
0.20
0.18
0.10
0.10
0.10
0.06
0.35
0.60
0.29
__
0.31
0.29
--
--
0.18
0.36
0.22
0.40
_-
0.22
._
--
--
--
»
Total N*
9.24
7.23
10.10
5.55
12.30
8.46
10.85
__
11.36
10.77
9.91
9.69
8.40
5.40
6.60
13.98
10.36
8.22
9.40
8.40
5.62
15.20
20.90
9.30
8.60
12.30
17.00
01
CJ
**
***
****
Values given are in mg/liter as Nitrogen
Saturday
Sunday
Labor Day
-------
TABLE A-XII (Continued)
NITROGEN DATA FOR KEHR PROCESS EFFLUENT
Date
10/7/67**
10/8/67***
10/9/67
10/10/67
10/11/67
10/12/67
10/13/67
10/14/67**
10/15/67***
10/16/67
10/17/67
10/18/67
10/19/67
Aeration
Peri od
4 hours
it
H
2 hours
H
II
II
II
II
II
II
II
II
NH:*
6.5
23.7
27.0
16.8
15.0
16.8
16.3
14.5
26.8
23.8
10.1
13.4
13.7
Oraanic-N*
3.2
2.7
3.2
11.8
3.3
3.3
2.3
2.4
2.0
3.2
3.5
2.0
1.7
NO^
Trace
Trace
0.01
«»
Trace
Trace
Trace
_
«
__
_»
--
N00*
_
«»
__
»M
0.12
..
«_
0.06
0.07
0.06
Total N*
9.70
26.40
30.21
28.60
18.30
20.22
18.60
16.90
28.80
27.06
13.60
15.47
15.46
* Values given are in mg-/liter as Nitrogen
** Saturday
*** Sunday
-------
FIGURE A-l
CORRELATION OF THE BODs
WITH THE TOC FOR
KEHR PROCESS SEWAGE
2000
1800
1600
1400
1200 ..
g 1000
2D
Sc
o
in
o
300 -.
C 600
ex:
UJ
o
400
200
0
e
e
« e
o
000
eo
200 400 600 800 1000
CONCENTRATION OF TOTAL ORGANIC CARBON (mg/liter)
65
-------
Electroflotatlon Theory
Flotation is a unit operation for separating two phases by introducing
gas bubbles which adhere to one phase causing a decrease in the apparent
density of that phase such that it will rise. Several methods which
have been used for introducing the gas are summarized by Virablik (7).
The gas used in electroflotation consists of hydrogen and oxygen produced
by the electrolysis of water.
The chemical reactions occurring at the electrodes to produce these gases
are shown below:
Anode Reaction:
2H20 -» 4H+ + 02t + 4e~
Cathode Reaction:
4e~ + 4H20 + 2H2t + 40H'
Total Reaction:
2H20 -» 2H2t + 02 +
From these reactions, it can be seen that for each 4 electrons of current
passed between the electrodes, one molecule of oxygen and two molecules of
hydrogen are formed. Or in more convenient terms, 0.174 cc of gas,
measured at standard temperature and pressure, are produced by each coulomb
of current.
Electrolysis of water produces small gas bubbles with diameters of the
order of 100 microns that are formed at the electrodes and rise as fine
mist.
Electroflotation has been considered for the separation of the biological
floe from mixed liquor because bubbles from the electrodes, when contacted
with mixed liquor, attach themselves to the individual floe particles
causing the floe to rise. The upward velocity of the floe and attached
bubbles is much higher than the settling velocity of the floe particles
alone. This allows a more rapid separation than with sedimentation and
can also yield a higher concentration of solids in the thickened stream
than with sedimentation.
The concentration of suspended solids in the effluent tends to decrease
as more of the mixed liquor solids are floated. How well the mixed
liquor solids are floated depends upon the number of bubble-solid
attachments that take place. As either the concentration of floes or
the concentration of gas bubbles are increased, the probability of attach-
ment also increases. This can be expressed mathematically, assuming that
66
-------
each increment of gas per gram of sol Ids creates a change in sol Ids
concentration proportional to the concentration of solids which the
gas contacts:
Then:
Where:
Integrating:
Where:
dC = kCdX (1)
C Concentration of solids below the sludge blanket
X = Volume of gas per unit mass of sludge
k = Constant
In Ci = kXf
(2)
C-j = The solids concentration in the feed
C2 = The solids concentration in the effluent
X^ = The total gas produced per gram of solids
To determine whether performance of electroflotation is described by this
model, the logarithm of the ratio of feed to effluent suspended solids
should be plotted as a function of the gas production per gram of solids.
If a straight line results then this model can be used to describe the
performance of the electroflotation cell.
67
-------
1
Accession Number
w
5
Q Subjei-t Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
FMC Corporation/Central Engineering Laboratories
P. 0. Box 580
Santa Clara, California 95052
Tl"e
Cannery Waste Treatment-Kehr Activated Sludge
10
Authors)
Robert A. Fisher
16
21
Project Designation
12060 EZP
Note
22
Citation
23
Descriptors (Starred First)
Cannery Wastes
Industrial Waste Treatment
Motivated Sludge Process
Aerobic Digestion
ELectroflotation
25
Identifiers (Starred First)
27
Abstract: The Kehr Activated Sludge Process (KASP), as practiced at FMU uorporation1 s
-Central Engineering Laboratories, uses a completely mixed aeration tank with no inten-
tional sludge wasting. The concentration of mixed liquor suspended solids was allowed to
stabilize at some value as a result of cellular synthesis, endogenous loss, and washout in
the effluent. The concentration of mixed liquor suspended solids ranged from 4,000 to 12,000
mg/liter. The BOD5 of domestic sewage and cannery wastes varied from 200 to 2000 mg/liter.
Removals obtained were 80 percent reduction in the concentration of total organic carbon and
a 90 percent reduction in the concentration of BOD*. The process was able to undergo a 40-
hour period of no organic loading with no loss of treatment efficiency when the organic load
was returned. The KASP appears to have an application for the pretreatment of industrial
wastes prior to discharge to a municipal sewer. The KASP, when use.d in this manner, could
handle intermittent waste discharge, produce 90 percent BODj removal and provide aerobic
digestion within the aeration tank. Exclusive of any primary treatment, the cost of treating
10 mgd of a waste containing 250 mg/liter of BODj using this high solids activated sludge
process is about 7$ per thousand gallons using gravity settling and about 29$ per thousand
gallons using electroflotation. The cost of pretreating 1 mgd of a waste containing 2,000
mg/liter BOD is about 28$ per thousand gallons exclusive of primary treatment. The report
was submitted in fulfillment of Grant 12060 EZP between th« Federal Water Quality Admin-
istration and the FMC Corporation.
Abstractor
Robert A. Fisher
Mf"Corporation/Central Engineering Laboratories
WR:!02 (REV. JULY '9691
WR3IC
SEND. WITH COPY Of DOCUMENT
TOl WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.f. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 10240
* U. S. GOVERNMENT PRINTING OFFICE : 1871 O - 412-973
------- |