''T FA
fliihfa^ WATER POLLUTION CONTROL RESEARCH SERIES • 12O6OFAD1O/69
Aerobic Treatment
of
Fruit Processing Wastes
U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER POLLUTION CONTROL 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, develop-
ment and demonstration activities of the Federal Water Pollution Control
Administration, Department of the Interior, through inhouse research and
grants and contracts with Federal, State, and local agencies, research
institutions, and industrial organizations.
Triplicate tear-out abstract cards are placed inside the back cover to
facilitate information retrieval. Space is provided on the card for the
user's accession number and for additional keywords. The abstracts
utilize the WRSIC system.
Water Pollution Control Research Reports will be distributed to requesters
as supplies permit. Requests should be sent to the Industrial Pollution
Control Branch, Department of the Interior, Federal Water Pollution
Control Administration, Washington, D.C. 20242.
Previously issued reports on the Industrial Pollution Control Branch Program
are:
DAST-7 "Cannery Waste Treatment by Activated Sludge" Oct., 1969
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AEROBIC TREATMENT
of
FRUIT PROCESSING WASTES
A Study of Aerated Lagoon, Activated Sludge, and Activated Sludge Reaeration
in the
Treatment of Fruit Cannery Waste
Sponsored by
OFFICE of RESEARCH and DEVELOPMENT
FEDERAL WATER POLLUTION
CONTROL ADMINISTRATION
Conducted by
SNOKIST GROWERS, INC.
YAK I MA, WASHINGTON
under
FWPCA Grant No. WPRD 58-01-68
Program No. 12060 FAD
OCTOBER, 1969
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price $1.25
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FWPCA REVIEW NOTICE
This report has been reviewed by the Federal Water
Pollution Control Administration and approved for
publication. Approval does not signify that the contents
necessarily reflect the views and policies of the Federal
Water Pollution Control Administration.
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ABSTRACT
In 1966, it was determined that the Snokist Growers cannery in Yakima,
Washington, was in need of further treatment facilities for the
cannery waste before the waste could be discharged into the Yakima
River. A system of aeration was proposed and a grant sought to aid in
construction of facilities and to study the results of the treatment
facility following construction. Facility construction proceeded in
two stages with addition of an aerated lagoon in 19^7 and the addition
of additional aeration and clarification facilities in 1968 to complete
the treatment system. The treatment system performed more efficiently
than initially expected in the original design assumptions, and nearly
99$ removal of BOD and COD from the waste stream was accomplished during
a major portion of the 1968 processing season.
The treatment systems were studied over the two operating seasons, and
operated as an aerated lagoon, as an activated sludge treatment system
and as activated sludge system but including sludge reaeration. Data
was collected on biological substrate assimilation, sludge growth,
oxygen uptake and sludge settleability. Constants were obtained from
this data. Success of the treatment system is reported and the costs
of treatment computed. It is recommended that aerated lagoon treatment^
be used where 70 percent removal of BOD is desired and suspended solids
are permissible in the effluent. Activated sludge treatment is
recommended for greater than 90 percent BOD removal and where effluent
suspended solids must be minimized.
This report was submitted in fulfillment of Grant No. 12060 FAD
between the Federal Water Pollution Control Administration and
Snokist Growers of Yakima, Washington.
iii
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CONTENTS
Abstract iii
Conclusions 1
Introduction 3
Purpose 3
Scope 3
Background U
Treatment Theory 6
Cell Growth 7
Oxygen Requirements 8
Aeration 8
Nutrient Requirements 9
Sludge Settling & Suspended Solids Removal 9
Design of Facilities 9
Existing Facilities 9
Design of 1967 Improvements 10
Design of 1968 Improvements 11
Construction of Facilities 13
1968 Construction ik
Operation of Project 16
Testing 17
Flow 17
Sample Testing 17
1967-1968 Operation . . . 17
Aerated Lagoon Performance 21
1967-1968 Activated Sludge 21
Buffering Capacity & pH Control 28
Nutrient Feeding 30
Sludge Settleability 30
Shutdown and Startup 30
Conclusions Drawn at the End of the 1967-1968 Processing
Season 31
1968 Processing Season Operation 31
Flow " 32
Testing Results 32
pH UO
Nutrient Feeding UO
Sludge Settling Characteristics U2
Startup ^3
IV
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CONTENTS - Continued
Discussion U3
Waste Load 1*3
Cost of Treatment U7
Substrate Removal 50
Biological Growth 59
Oxygen Requirements 69
BOD & COD Content of Biological Sludge Ik
Nutrient Requirements 75
Effects of Nutrient Deficiency 79
Biological Solids Removal 82
Sludge Wasting & Disposal 85
Aeration Basin Temperature Prediction 85
Recommendations 89
Future Studies 89
Future Operation 89
Future Designs 90
Acknowledgement 91
Bibliography 93
Appendix A 95
Appendix B 105
Appendix C Ill
Appendix D 126
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FIGURES
Figure Page
1. Schematic Flow Diagram - 1967-1968 Processing
Season 18
2. Treatment Facilities - 1967-1968 Processing
Season 19
3. Flow - 1967-1968 Processing Season 20
k. 1967-1968 Aerated Lagoon Performance - BOD 22
5- 1967-1968 Aerated Lagoon Performance - COD 23
6. 1967-1968 Aerated Lagoon Performance - VSS 2k
7. 1967-1968 Activated Sludge Performance - BOD 25
8. 1967-1968 Activated Sludge Performance - COD 26
9. 1967-1968 Activated Sludge Performance - VSS 27
10. 1967-1968 Aerated Lagoon Performance 29
11. 1967-1968 Activated Sludge Performance - pH 29
12. Schematic Flow Diagram - 1968 Processing Season ... 33
13. Treatment Facilities - 1968 Processing Season .... 3^
lU. Flow - 1968 Processing Season 35
15. 1968 Treatment System Performance - BOD 3°
16. 1968 Treatment System Performance - COD 37
17. 1968 Treatment System Performance - VSS 38
18. 1968 Treatment System Performance - pH ^1
19. Crystal Clear Clarifier Effluent During 1968
Processing Season ^
20. COD Removal Rate vs. Concentration 51
21. COD Removal Rate vs. Concentration 52
22. COD Removal Rate vs. Concentration 53
23.- COD Removal Rate vs. Concentration 5^
2k. COD Removal Rate vs. Concentration 55
25. COD Removal Rate vs. Concentration 5^
26. COD Removal Rate vs. Concentration 57
27. COD Removal Coefficient vs. Temperature 58
28. BOD Removal Rate vs. Concentration at 20° C 60
29. Net Sludge Growth vs. COD Removal Rate 62
30. Net Sludge Growth vs. COD Removal Rate 63
31. Net Sludge Growth vs. COD Removal Rate 6k
32. Net Sludge Growth vs. COD Removal Rate 65
33. Net Sludge Growth vs. COD Removal Rate 66
3k. Net Sludge Growth vs. COD Removal Rate 67
35. Endogenous Respiration Rate vs. Temperature 68
36. Oxygen Uptake Rate vs. COD Removal Rate 71
37. Oxygen Uptake Rate vs. COD Removal Rate 72
38. Oxygen Uptake Rate vs. COD Removal Rate 73
39. BOD, COD Equivalent of VSS 7°
kQ. Nitrogen and Phosphorus Content of Biological Sludge . 7°
Ul. Nitr.ogen and Phosphorus Requirements for Treatment . . 80
te. Sludge Volume Index vs. COD Removal Rate - 1968 ... 8U
U3. Aeration Basin Temperature Relationship 88
A-l. Large Aeration Basin Showing Three of the Four 60 H.P.
Aerators, 150 H.P. Aerator, PVC Lining on Dike, and
Influent Structure 1°°
vi
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FIGURES - Continued Page
A-2. Waste Treatment System from Screening Station
Platform 101
A-3. 30 H.P. Aerators in Small Aeration Basin 101
A-U. Large Aeration Basin - Aerators Operating 102
A-5. Final Clarifier; Small Lagoon Screening Station,
Cannery Building and Sludge Pump Building in
Background 102
A-6. Sludge Recirculation Pumps and Piping in Sludge
Pump Building 103
A-T- Waste-water Laboratory Interior 10^
B-l. Typical Daily Processing Flow H°
C-l. Sludge Settling Curves 112
C-2. Sludge Settling Curves H3
C-3. Sludge Settling Curves H1*
C-U. Sludge Settling Curves H5
C-5. Sludge Settling Curves H°
C-6. Sludge Settling Curves H7
C-T. Sludge Settling Curves H8
C-8. Sludge Settling Curves H9
C-9- Sludge Settling Curves 120
C-10. Sludge Settling Curves 121
C-ll. Sludge Settling Curves 122
C-12. Sludge Settling Curves 123
C-13. Sludge Settling Curves 12^
C-lU. Sludge Settling Curves 125
D-l. YSI Standardization Curve 128
D-2. YSI Correction Curves 129
D-3. Oxygen Uptake Rate 130
D-U. Oxygen Uptake Rate 131
D-5. Oxygen Uptake Rate 132
D-6. Oxygen Uptake Rate 133
D-T. Oxygen Uptake Rate 13^
D-8. Oxygen Uptake Rate 135
vii
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TABLES
Table Page
I Facilities Existing at Start of Project 10
II 196T-1968 Aerated Lagoon Performance 21
III 1967-1968 Activated Sludge Performance 28
IV 1968 Processing Season Treatment Resulta 39
V Cost of Waste Treatment - Total System ^7
VI Estimated Costs of Separate Methods of Treatment . ^8
VII Aerator Oxygen Transfer Efficiency 7^
A-I Costs of Construction of Treatment Facilities ... 9°
A-II Manufacturers or Suppliers of Major Equipment ... 9^
A-III Cost of Operation of Treatment Facility 99
viii
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CONCLUSIONS
Conclusions from this two year study of the treatment of fruit
processing waste by aeration are as follows:
(l) Activated sludge or contact stabilization treatment of
fruit processing waste at low rates (below O.U mg COD
removed per day per mg MLVSS) will provide greater than
90 percent removal of organic load and removal of solids
from the effluent. The activated sludge process does as
adequate a job as contact stabilization and would be
recommended because of requiring less facilities and thereby
lower cost.
(2) Aerated lagoon treatment can provide greater than 70
percent BOD removal but suspended solids remain in the
effluent and are the principle source of effluent BOD and
COD. This treatment is considerably less expensive and is
recommended if the effluent quality can be tolerated.
(3) "Completely mixed" aeration basins provide effective buffering
to avoid pH fluctuation-.
(U) Final clarification for activated sludge or contact stabil-
ization is successful at low surface loading rates (below
UOO gallons per square foot per day), made necessary by the
slow-settling sludge developed, and with vacuum type sludge
removal.
(5) Nutrient addition is necessary to achieve successful treat-
ment . Nutrient savings can be made by increasing the amount
of biological sludge in the system, thus decreasing the
waste loading rate on the sludge. This allows a greater
destruction of sludge by endogenous respiration which returns
nutrient to the system and cuts down the amount necessary to
add. Activated sludge or contact stabilization treatment is
necessary to accomplish this.
(6) Surface aerators accomplished adequate mixing at 0.3 HP/1000
cubic feet and provided 2 pounds of oxygen transfer per
horsepower hour under operating conditions.
(7) PVC sheeting is a suitable basin lining material provided
adequate diligence is expended in assuring sound field welds
at all joints. It is recommended that the bottom be covered
with sufficient material to prevent it from floating even if
gas should accumulate beneath it.
C8) 'The biological sludge developed seemed to be independent of
the type of fruit processing waste and had the following
characteristics:
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(a) about 90 percent volatile
(b) settled very slowly
(c) settling improved at low COD and BOD removal rates
(d) mg COD/mg VSS =1.39
(e) mg BOD/mg VSS = 0.3 + 0.28 x BOD removal rate
(f) mg Organic N: mg Organic P: mg VSS = 0.087: 0.0l6: 1
(9) Net Sludge Growth/day = C x Substrate removed/ day - k^ x MLVSS
where c=O.U9 mg vss formed for Pear processing waste
mg COD removed
C=0.U6 mS VSS. fo™ed for Peach processing waste
mg COD removed
mg VSS formed processing waste
mg COD removed v* v
k =0.115 x 1.1U(T-20)
t
ro
mg MLVSS-day
=Endogenous respiration rate at T °C
(10 ) Substrate removal rate = f, x Substrate Concentration
=n ni7 v i -20) mg COD removed _
J-' -
t - - mg MLVSS-day-mg/1 COD
=0.068 x 1.16(T-20) mg- gP^ moved .. .
mg MLVSS-day-mg/1 BOD
= Substrate removal rate coefficient
(ll) Oxygen required/ day = a x substrate removed/ day + b x k . x MLVSS
a=0.3^ mg 0 reguired/mg COD removed
=O.U6 mg 02 req.uired/mg BOD removed
13=1.2 mg Oo required/mg VSS destroyed by endogenous
respiration
(12) Cost of treatment is estimated to be :
$O.OUl/#BOD removed for Aerated Lagoon
$0.06l/#BOD removed for Activated Sludge
$0.06T/#BOD removed for Contact Stabilization
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INTRODUCTION
PURPOSE
The purpose of this project, "Pollution Prevention by Aeration of
Fruit Processing Waste," carried out by Snokist Growers, Yakima,
Washington, was to develop a treatment system whereby 90% of the
organic content of the waste from their fruit cannery would be removed
prior to the wastes discharge into the Yakima River, a tributary of
the Columbia River. This organic matter to be measured as biochemical
oxygen demand (BOD) was to be removed according to requirements of the
State of Washington Water Pollution Control Commission which also called
for removal of suspended solids from the effluent to the river. Also,
operating data and experience was to be gained on the methods of
treatment proposed in order to evaluate them and develop criteria for
the design of other systems on similar waste streams in other locations.
The collection of data on construction methods and costs of operation
would be included in the project in order to help judge the feasibility
of the treatment.
Three methods of treatment by aeration were selected for study and
comparison: (l) Aerated Lagoon - The aeration of the waste in a
completely mixed basin without removal of sludge (suspended solids)
from the effluent and without sludge recycle. (2) Activated Sludge -
Aeration with suspended solids removal by settling and the return of
sludge to the aeration basin, sludge recycle, with the incoming waste.
(3) Contact Stabilization or Activated Sludge with sludge reaeration -
The sludge is removed from the aeration basin effluent and aerated
alone for a period of time prior to return to the aeration basin with
the incoming waste.
SCOPE
The scope of this project was to include construction of adequate
facilities for the treatment of a waste stream at Snokist Growers
cannery, and the study of the treatment methods. The facilities to
be constructed would allow concurrent testing of flow through aeration
basin or aerated lagoon facility and activated sludge or aeration with
sludge return facility during the first season of operation, and further
study of the sludge return and aeration process and additionally, sludge
return with sludge reaeration during the second season of operation.
During the second season of operations "secondary treatment" or removal
of the required amount of organic loading as required by the State of
Washington was to have been attained on the full waste stream, in
addition to the removal of suspended solids from the effluent, as is
also required by the State Water Pollution Control Commission.
Testing was to be carried out to obtain the efficiency of the waste
treatment methods and the parameters of aerobic treatment of the
waste including the biological growth characteristics, waste assimilation
characteristics, oxygen uptake requirements and other characteristics of
the waste flow which affect the treatment system operation and design.
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These other characteristics include the waste load developed "by the
process in the cannery and the solids removal problems from the
aerated waste stream. It was to be determined if efficiencies could
"be made in the addition of nutrient chemicals, nitrogen and phosphorus,
and the application of power for aeration of the treatment facility "by
changing operational parameters.
Data on dissolved oxygen, temperature, pH, and settleable solids
collected within the aeration basins, data on suspended solids,
volatile suspended solids, total and volatile total solids in the
influent and the effluent and chemical and "biochemical oxygen demand
would be gathered over the periods of operation of the facility during
the study period. Nitrogen and phosphorus analyses would be made.
Analysis of the test data would be made and presented in a final report
along with cost records to allow evaluation of the system by others
anticipating handling similar waste problems.
BACKGROUND
In 1966 during the fruit processing season, a treatment system
consisting of screening of the waste flow from the Snokist Growers
cannery, followed by an aeration basin containing two 30 horsepower
aerators was being utilized. A small rectangular clarifier was
also being used to recirculate the waste settleable solids back to
the headworks of the lagoon. Tests had been run by the Washington
State Water Pollution Control Commission and by Washington State
University which indicated that the system was achieving very poor
treatment on the waste stream from the cannery. The State requested
that Snokist Growers develop a plan whereby the waste stream entering
the Yakima River would meet the requirements of the State of Washington
which included 90% removal of the organic content of the waste and the
removal of suspended solids from the waste stream. Since the aeration
system that had been installed for the cannery was apparently not
satisfactory for the waste and its treatment, there was considerable
discussion as to the methods of attaining the State's requirements.
An analysis of the data accumulated by Snokist Growers personnel,
the State Water Pollution Control Commission and the Washington State
University indicated that the system was grossly overloaded and did
not give a true indication of what a properly designed system could
yield in the way of treatment.
It was then decided to seek a Research and Development grant from the
federal government who had shortly before that time announced a
program whereby treatment projects of a research and development
nature could be partially financed in order to develop data on systems
for the treatment of industrial wastes. A system whereby stage
construction would be made toward eventual complete treatment of the
waste was decided upon and where the following year's operation would
consist of an aerated basin without sludge settling or sludge return
would be used to treat a majority of the waste flow and where the
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existing system would "be used as an activated sludge system on a
small portion of the waste flow in order to gather testing data on
each type of system. Following one year of operation in this manner,
further facilities were to be constructed in order to allow sludge
return and suspended solids removal from the waste coming from the
aeration basin and, in addition, would allow recirculation of the
sludge removed through the small existing aeration basin for sludge
reaeration prior to its remixing with the influent waste flow in
the large aeration basin.
This construction and operating schedule was approved by the Water
Pollution Control Commission since it did not appear feasible to
install complete treatment facilities for the first season because
of equipment delivery time and, because of the many unknowns
surrounding the process, the design would be quite difficult and
would necessarily be based on many assumptions which had not been
confirmed in any operating facility to that date.
Aeration of wastes for their treatment is not a new concept but
has been tried quite extensively on pulp and paper waste streams
and somewhat in the fruit and vegetable processing industry. Results
of aeration of wastes similar to the waste stream that was experi-
enced at Snokist Growers was unknown so that parameters for the
design of a system of this type had to be largely derived from
knowledge of the basic treatment process from operations on other
types of waste and from the meager data which was available from
the studies by the State University and Pollution Control Commission.
In I960, the treatment of industrial waste in so-called aerated
lagoons (l) was being developed along with surface aerators which
alleviated the necessity of extensive piping and blower arrangements.
These surface aerators which consist of a gear motor driving an open
impeller were developed by several manufacturers and although they
are of different shapes, each manufacturer's claims are for approxi-
mately the same efficiency of oxygen transfer. These aerators allow
the aeration of open basins without fixed linings and without as
rigid compliance to basin configuration as was necessary for diffused
air aeration. Also, surface aerators tended to give the basin's
contents a more "complete mixed" nature when sufficient horsepower
was available to the basin. This completely mixed state within the
basin allowed the use of "complete mix" theory for the biological
treatment process and, in addition, allowed the entire contents of
the aeration basin to assimilate the waste flow as it enters the
basin, thereby giving an increased buffer capacity for high strength,
variable strength, and high or low pH waste streams.
The development of these surface aerators by equipment manufacturers
and their acceptance into use (as attested by the existing installation
of two 30 horsepower aerators in an aeration basin at the cannery)
was not accompanied by development of theory and parameters for use
in the actual treatment process.
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TREATMENT THEORY
The theories of biological treatment have "been published by several
authors, including Eckenfelder, Stewart and Pearson [1, 2, 3, and U].
These theories , generally based on theory derived from observation of
culture growth and reactions by bacteriologists and expanded for use
with biological waste treatment systems are generally not too far
apart and a composite theory of waste treatment process which can be
incorporated into design can readily be attained therefrom. The
attainment of a completely mixed system by the use of the aeration
methods previously described allow the use of steady state removal
of substrate (BOD and COD) by the biological mass measured as volatile
suspended solids (VSS) according to these Kinetic equations. The
Michaelis-Menton Kinetic equation has been suggested as most closely
describing substrate (COD and BOD) removal. This equation establishes
the BOD and COD removal as equal to the maximum rate of removal of
BOD or COD per unit mass of organisms times the residual BOD or COD
concentration in a solution, divided by the sum of this residual
BOD or COD and the residual BOD or COD at one-half the maximum
substrate removal rate. Equation (l) shows this relationship where
R = —— Michaelis-Menton Rate Equation (l)
S+s
R = BOD or COD removal rate mg BOD, COD/mg MLVSS-day
F = Maximum removal rate
S = BOD or COD concentration at R = 1/2 F, Michaelis Constant
s = BOD or COD concentration, substrate concentration
This equation, when R is plotted against s, the concentration,
provides a curve which starts upward from zero and gradually decreases
in slope until it is horizontal at the asymptotic line which represents
F. Since F is usually large as compared to a normally operating
treatment system where R is normally much less than one, .this equation
can be substituted by a straight line equation such as equation (2)
R-= fs Simplified Rate Equation (2)
f = BOD or COD removal coefficient i*S BOD or COD removed
mg MLVSS-day-mg/1 BOD or COD
without introducing a sizable error. This straight line which has a
slope f is valid only for low values of R. This slope f which we will
term the BOD or COD removal coefficient can be much more readily ob-
tained from operating data of treatment systems than can be the two
constants F and S which must be obtained in order to use equation (l).
The substrate BOD or COD concentration in a completely mixed system
(s) is a constant since the entire contents are completely mixed
and the effluent is also of this same concentration. TMs provides
a constant base concentration so the kinetic equations (l) and (2)
become valid only in a completely mixed system.
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Cell Growth
It has "been observed both from the "bacteriological culture experiments
and subsequent waste treatment experiments that there is a particular
conversion rate of substrate to cell material which is a constant for
a particular waste and waste system. This constant represents the
milligrams of cellular material formed from the removal by organisms
of a milligram of BOD or COD from the waste. This constant which is
always less than one reflects that the remaining amount of energy in
the removed BOD and COD is utilized in the formation of the cells.
The constant ratio of conversion apparently holds true regardless of
removal or reaction rate and activity of the biological mass. It has
also been shown that there is a rate of destruction of cells which
occurs simultaneously with the cell growth. This destruction, termed
endogenous respiration, is apparently not affected by the reaction
rate of treatment system, but is probably affected by biological
activity, primarily linked to the temperature of the system. The net
sludge growth, therefore, can be presented as shown in equation (3)
Net Sludge Growth = c'BOD or COD removed/day-k'MLVSS (3)
c = Sludge Growth Constant-mgVSS formed/mg BOD or COD removed
k = Endogenous Respiration Rate-mgVSS destroyed/mgMLVSS-day
MLVSS = Mixed liquor volatile suspended solids
The MLVSS is assumed proportional to the active biological mass in
the system. Equation (3) can be divided by the mixed liquor volatile
suspended solids and since equation (U) is the definition of removal
rate, equation (5) can be formed.
R = BOD or COD Removed/Day (1^)
MLVSS
G = cR-k Net Sludge Growth Rate Equation (5)
G = Net Sludge Growth Rate mg VSS/mgMLVSS-day
MLVSS here refers to the total weight of volatile suspended solids in
the treatment system and the net sludge growth rate (G) consists of
cells or volatile suspended solids accumulated in the system, those
which are wasted from the system as carryover in the effluent and
those intentionally removed by wastage of settled solids, divided by
the total VSS in the system. In a steady state system the effluent
substrate would remain constant as would the MLVSS and, therefore, so
would the net sludge growth. In a non-steady state system, a portion
of the net sludge growth could be accumulated in the system or excessive
volatile suspended solids wastage could be carried on and the MLVSS
increasing or decreasing, or the substrate could vary. The reciprocal
of the Net'Sludge Growth Rate is the "Sludge Age" of the biological
solids in the system.
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Oxygen Requirements
In an aerobic "biological treatment system, oxygen is required for
energy production for conversion of the substrate to cellular matter
and also for the continual maintenance of the biological mass or
endogenous respiration. The oxygen required in a steady state
operating treatment system can "be computed by using equation (6).
Og = a- BOD or COD removed + b'k'MLVSS (6)
02 = Oxygen required
a = constant, mg02 required/mg BOD or COD removed-day
b = constant, mgOg required/mg VSS-day
By dividing equation (6) by the MLVSS we obtain equation (7)» which
can be used to evaluate the constants in the equation from operating
data.
0 /MLVSS = a-R+b-k (?)
Aeration
Surface aerator manufacturers have done considerable work on their
own impeller designs in order to achieve their optimum oxygen transfer
efficiency and in order to evaluate their particular machine's per-
formance. Most surface aerator manufacturers claim to get between
3.5 and k pounds of oxygen transferred per hour per horsepower hour
expended at "Standard conditions". These standard conditions include
clear, suspended solids and organic-free water, one atmosphere of
pressure (sea level), temperature at 20°C. and Omg/1 of dissolved
oxygen. Solids and organics in the water lowers the ability for the
water to take gaseous oxygen into solution as rapidly as clear water
does and, therefore, these figures must be reduced when being applied
to a waste treatment system. Also, the aerators are evaluated at
zero dissolved oxygen so a maximum dissolved oxygen differential
exists between the surrounding gaseous oxygen in the air being fused
into the water by the impeller's action and the water itself. In a
treatment system a certain amount of dissolved oxygen must be main-
tained in order to sustain the biological growth and not cause oxygen
deficient conditions in a portion of a system. This 1 to 2 milligrams
per liter dissolved oxygen which must be maintained decreases the
dissolved oxygen deficit, the driving force for solution of oxygen.
into the water, which also reduces the factor presented by the companies
for their aerators. These two corrections, usually referred to as
alpha and beta, must be used for design. Taking these factors into
account, an oxygen solution capacity of approximately two pounds of
oxygen per horsepower hour expended is normally expected from surface
aerators of this type during actual operation in the field.
8
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Nutrient Requirements
It has "been recommended [2] that a BOD to nitrogen to phosphorus
ratio in the influent to a "biological system be maintained at 100:5:1
in order to assure proper biological grovth conditions. This amount
of nitrogen and phosphorus is required to provide the cells with
adequate nutrients to form the cellular protein. It has "been
suggested elsewhere [9] that variation in nutrient feeding should
follow the sludge age or BOD removal rate.
Sludge Settling and Suspended Solids Removal
At the beginning of this project there was very little published
data on sludge characteristics from industrial wastes and none on
fruit processing wastes which was applicable to the conditions which
were anticipated. It had been observed, however, that sludge
growths, when obtained from carbohydrate wastes resist settling out
and resist flocculation into a thicker mass. This was a portion of
the reason for delaying the installation of full scale clarification
facilities until the second year of the project in order to allow
further study of the settling and clarification characteristics
during the first season of operation.
DESIGN OF FACILITIES
In the design of facilities for this project, three criteria were
involved.
1. To utilize the facilities already existing to the maximum
amount possible.
2. To achieve a system whereby continued high degree of
treatment would be available for the waste system in
the future at the design loadings.
3. To make the system flexible enough to gather data over
a wide range of operation for evaluation of the treat-
ment system and the three proposed types of treatment.
EXISTING FACILITIES
Facilities which had been constructed prior to 1967 were available at
the start of the project. The design for the project attempted to
incorporate these facilities as fully into the treatment system as
was possible. A screening station which consisted of two vibrating
screens with a lift station to lift waste over the screens and to an
elevation higher than the treatment facilities was available. This
screening station is adequate for the waste load and does a suitable
job of removing large solids particles from the waste stream leaving
a screened effluent with nearly the entire organic load in the
soluble state. There also existed an earth basin with sprayed-on
asphalt lining to prevent waste infiltration into the ground water,
equipped with two 30 horsepower turbine type surface aerators. A
hopper bottom rectangular clarifier accompanied this aeration basin.
-------
and a return pump to recirculate settled sludge from the "bottom of
the hopper cones to the headworks of the aeration basin.
An outfall sewer from the aeration basin location to the Yakima
River was also available and was hydraulic ally adequate to carry
the waste from the treatment site to its discharge in the Yakima
River.
TABLE I
Facilities Existing at Start of Project
1. Lift Pumps & Screening Station - Open Impeller Pumps and two
Vibrating Screens
2. Aerated Basin - Earth Dikes - Asphalt Lined
136' x 236' § Water Surface x 8' Deep - 1.5 MG Capacity
3. Aerators - 2 - 30 HP Turbine Aerators
U. Clarifier - Rectangular, Hopper Bottom - 200 gpm pump for
sludge removal - W.S. = 1070 ft.2, Depth =12', Vol. = ^7,700 gal.
5. Outfall Line to River
DESIGN OF 1967 IMPROVEMENTS
The 1967 improvements were designed to provide an aerated lagoon
facility of adequate capacity to treat the waste which was not
capable of being handled in the existing aeration basin clarifier
system. Design loading based on Snokist Growers' records and the
studies made by Washington State University and the Washington Water
Pollution CJpntrol Commission in 1966 were as follows:
1967 Design Loading
Flow 2 MGD
BOD (after screening) 20,000#/day
Both nitrogen and phosphorus were considered deficient. The existing
facility could handle only approximately 10 to 15 percent of this
waste load based on the 2#/HP hour-probable transfer capability of
oxygen by the existing 30 horsepower aerators.
The design of the aerated lagoon was based upon treatment constants
as derived from the data collected by the Pollution Control Commission
study and Washington State University in their study. This data was
derived by analysis of the two stu,dies and comparison through trial and
error analysis of these two sets of data. The following constants were
obtained for the new design:
c = 0.6 mgVSS/mg BOD removed
k = 0.05 mgVSS/mg MLVSS-day
f = 0.0022 m BOD removed
MLVSS-day-mg/1 BOD
a = 0.6 mg Og/mg BOD removed
b = 1.5 mg 02/mg VSS-day
10
-------
In a steady state operating condition of an aerated lagoon which
enjoys complete mixing, it can be seen that since
G = Net Sludge Growth,
Net Sludge Growth = VSS x Q
and
MLVSS = VSS x V
that .
G = &=i (8)
V t
where
Q = Waste Flow
V = Basin Volume
t = Hydraulic Detention Time-Days
Equation (8) is valid only for completely mixed aerated lagoons.
Equation (9) can "be derived and is an equation which is also valid
for completely mixed aerated lagoons only
r- = cR-k = cfs-k Aerated Lagoon Equation (9)
u
An aerated lagoon design was made using 1.7 MGD and 17,000#/day of
BOD (85$ of the design figures) or a BOD concentration of 1200 mg/1.
An effluent BOD of 252 mg/1 was computed for a "basin of 6 million
gallons volune.In addition to this substrate BOD, an assumed factor
of .25 x the effluent volatile suspended solids (U80 mg/l) as the
BOD load of VSS in the effluent was assumed which would give a
372 mg/1 total BOD load in the effluent or 69% predicted removal of
BOD. The constants assumed would also give a 9»900#/day oxygen
demand on the aerators in the lagoon. Based on the limitation of
2# of oxygen transferred per horsepower-hour, 206 horsepower in
aerators would be required. Since this 2#/HP-hour figure had not
been borne out in actual tests it was decided to install four 60
horsepower aerators or 2UO horsepower in aeration capacity on the
proposed 6 million gallon basin. This basin was to be 280 feet
by 280 feet surface area and 12-1/2 feet in depth with the aerators
located in the four corner quadrants. In the actual installation,
the aerators were located offset slightly toward the outside corners
of the lagoon in order to allow for the possibility of adding
additional aeration capacity in the center of the lagoon during
the next year's expansion. The horsepower of aerators selected
equaled 0.3 HP/I000 cubic feet of basin.
DESIGN OF 1968 IMPROVEMENTS
The 1967 operating season gave us considerably more data with which
to design for complete treatment of the entire waste stream. The
design loading for the treatment facility for the 1968 expansion
to what was intended to be a complete secondary treatment facility
as required by the State of Washington Water Pollution Control
Commission were as follows:
11
-------
Flov = 2.5 MGD for 16 hrs/day
BOD = 28,000#/day
COD = 35,000#/day
Treatment parameters for use in the design equations, as presented
earlier, were changed somewhat from those assumed for 196?, although
data was not sufficient to revise these figures greatly as of that
time.
c = 0.6 mg VSS/mg BOD removed
k = 0.05 mgVSS/mg MLVSS-day
f = 0.005 mg BOD removed
mgMLVSS-day-mg/1 BOD
a = O.U5 mg Og/mg BOD removed
"b = 1.5 mg 02/mg VSS-day
Oxygen transfer capability of aerators 2.0#/HP hr-
The 1968 design had to "be more complex than the 19^7; for complete
treatment as was required, it was necessary to remove the suspended
solids from the effluent. It was noted during the 1967 season that
sludge grown in the aeration "basin without sludge recycle, displayed
little, if any, propensity towards settling, whereas, the .sludge
grown in the activated sludge portion even though the clarifier
was of poor design and quite inefficient, did show settling char-
acteristics far superior to the sludge from the aerated lagoon.
After study of the settling curves from the activated sludge system,
it was decided that circular clarifier with a vacuum sludge removal
system would "be the most efficient for this purpose and that recycling
sludge to the aeration basin would be a definite necessity. This
would increase the MLVSS to a point where the removal rate of BOD
by the organisms was low enough that the sludge would maintain
acceptable settling characteristics. An overflow rate of UOO
gallons/square foot/day was selected for the design area of the
clarifier and the ability to recycle sludge at twice the influent
flow rate was deemed desirable.
It was assumed that a volatile suspended solids concentration of
1,800 mg/1 could be maintained in the aeration basin during normal
operation and using this assumed figure and the constants given
above with the design loading, it was determined that a requirement
of 396 horsepower would be necessary to supply sufficient oxygen
to the aeration basin if the entire waste stream went through the
large basin. The addition of a single 150 horsepower aerator,
the largest available, in the center of that basin along with the
k - 60 horsepower aerators installed the previous year, would
supply 390 horsepower. This was decided to be sufficient. At
steady state conditions , a sludge wasting rate of 12,800#/day of
suspended solids was anticipated from the system operating at the
loading given.
12
-------
The clarifier of circular design at an overflow rate of UOO gal/square
foot/day and 2.5 MOD design flow was required to contain 6,250 square
feet of surface area or would require a 90 foot diameter unit. An
8 foot side water depth would yield a volume of HUo,000 gallons for
detention time of k hours 15 minutes for the design flow. Two sludge
recycle pumps, both variable speed, and of 2.5 MGD or 1750 gallon
per minute (GPM) capacity would give a sludge recycle ratio of twice
the expected waste flow. This recycle ratio could be varied downward
as necessary and the two pumps could be utilized to recycle sludge
both to and from the small lagoon for reaeration prior to its reintro-
duction into the large lagoon if settling characteristics of the sludge
allowed the sludge recycle rate to be at or less than the single pump
capacity.
In order to increase the concentration of the sludge for its haul to
land disposal, a flotation sludge thickener was deemed necessary even
though no data had been developed to indicate this would be a workable
system. Several manufacturers of waste treatment equipment had flota-
tion thickeners available and it was decided that a thickener with a
maximum sludge loading of 2#/SF/hour for wasting 900# of waste sludge
per hour, a maximum overflow rate of 1.5 gal/min/SF and a minimum
dissolved air capacity of 0.3#/minute would be let out for bid and
constructed. Included was the ability to add Polymers to aid the
sludge flocculation and thickening.
CONSTRUCTION OF FACILITIES
The facilities added onto the existing treatment system at the
cannery occurred over two years. In 19&7, an additional aeration
basin lined with polyvinylchloride (PVC) sheet and equipped with
four 60 horsepower column mounted surface aerators was constructed.
Also installed was a flow metering and splitter box and necessary
piping, boxes and appurtenances to tie the new basin into the influent
and effluent system.
The surface aerators were bid upon by four manufacturers of such
equipment and included the mounting platform. The aerators are
mounted on concrete piers with galvanized rod cross bracing and
were accessible from walkways leading from the bank. The earth
dikes were constructed by earth moving equipment and compacted
with water addition. C-76 class IV concrete sewer pipe with rubber
ring joints was installed for influent and effluent piping. The
influent flow measuring and diversion box was constructed so that
the flow could be proportioned between the two aeration basins and
metered through a two foot rectangular weir.
The 0.020 inch polyvinylchloride (PVC) basin liner was selected
due to the difficulties which had been experienced with the sprayed
on asphalt liner in the original construction of the small existing
basin. The manufacturer and supplier of this liner advocated its
use without cover and laid directly on the bottom with the exception
13
-------
of around the term of the dike where an earth cover vould "be placed
to protect the liner from the sun's direct rays, which would tend to
age the material. The liner installation went smoothly and apparently
a satisfactory installation jot was done. However, following about
a month of operation of the system, tuttles "began to appear in the
liner at the water surface. Upon the advice of the manufacturer and
concurrence with the engineers of the project, the "buttles were
punctured to allow the liner to settle tack to the lagoon tottom.
Dewatering of the lagoon the following spring, (March, 1968) showed
that the liner had failed along several of the "welded" seams which
were done in the field. These failures, some of them of consideratle
length and one of which had parted at least six feet, were apparently
allowing wastewater to get underneath the liner and tecome anaerotic,
therety causing gas to carry the liner to the surface. Repair work
was instigated ty the cannery in cooperation with the original installer
of the liner. This repair work consisted of dividing the liner into
sections and its removal from the lagoon to allow shaping of the
lagoon tottom teneath the liner to slope upward to the sides of the
lagoon which would allow gas to escape, and in addition to remove
from teneath the liner the accumulated sludge layer which was nearly
an inch thick over much of the tottom prior to replacement of the
liner. The liner was replaced and covered with a six inch to one
foot layer of round rock to hold it in place and prevent further
flotation even if some gas did develop teneath the liner. Another
contrituting factor to the liner's flotation apparently was the
fluctuating ground water table in the area which, during certain
portions of the year drops well telow the lagoon tottom, whereas,
during the spring and summer, when heavy irrigation is carried on
in the Yakima Valley, the water tatle tecomes two or three feet
atove the tottom elevation. This possitly entraps air tetween the
liner and ground water. The PVC liner has given completely satis-
factory service since its reinstallation and covering. It would
te recommended on future installations .that covering of the liner
te done at the initial installation as a precautionary measure
against unknown protlems. It is also recommended that very careful
supervision and testing te maintained full time during the liner
installation to avoid the possitility of poor field "welding".
1968 CONSTRUCTION
The construction of facilities for 1968 tegan in Fetruary, 1968 with
the calling for tids on equipment to te installed during that
construction season. Placed out for tids at that time were the
150 horsepower surface aerator, including platform and steel support
legs and cross tracing; the suction clarifier mechanism for a 90
foot diameter clarifier; two variatle speed sludge pumps with
1750 gallon/minute capacity; and flotation sludge thickener.
Following the tid opening on March 1, this equipment^, was put on
order and plans and specifications were tegun for their installation.
Bids were also called and contracts let on a latoratory tuilding to
te tuilt, using a common wall with one of the cannery's warehouses,
lU
-------
and to include laboratory space for all of the tests which were to
"be run for the treatment project and connected research. The labora-
tory "building is of concrete block construction, 22 feet by 36 feet
inside dimensions, complete with cabinets, counters and equipment.
Considerable additional laboratory equipment was available from the
first season's operation and from purchases prior to this project.
Bids were called the latter part of May for construction of
auxiliary facilities and for installation of the equipment contracted
earlier in 1968. The timing was set up on this contract so as to
have the installation of equipment completed for operation during
the 1968 season. The actual delivery of the equipment and installation
was somewhat delayed so that the clarification operation and sludge
return did not get into operation until early September. An early
beginning of pear harvest and pear processing allowed more of the
season to pass by them had been anticipated. However, the majority
of the season was covered by the facility being in operation so that
"complete treatment" was experienced, and additionally, a wide range
of operating variables were covered to gain added data points for the
evaluation of this treatment of fruit processing wastes.
Appendix A contains photographs of equipment and structures utilized
in the project. Table I in Appendix A contains costs of construction
of facilities including the facilities prior to the beginning of the
project. These costs are broken down by items in order to more
readily lend the cost data to estimation for other
facilities. Appendix A, Table II contains the manufacturer's name
of major treatment equipment items utilized for this project.
With the exception of the lagoon liner, no difficulties were experi-
enced with any of the equipment items during the project's operations.
However, following the shutdown during the 1968 season of the facilities
the aerators on the large aeration basin were operated in February
to prevent odors from developing from the sludge in the system.
This system had frozen over in December following the shutdown of
the processing line and the aerators had been shut down for a period
of time prior to restarting when the ice thawed off the basin.
Shortly after restarting the aerators, one of the original 60
horsepower aerator gearmotors began sounding quite badly and was
shut down. Inspection showed that a misalignment of shafting had
occurred and several gear teeth were missing on some of the major
gears. The initial tooth breakage was because of a shaft misalign-
ment caused by the shaft slipping out of its bearing. Teeth on
other gears in the gearmotor were broken off when pieces of the
teeth from the initial broken gear flew into them. There appeared
to have been some mismanufacture of the part that slipped out of
its bearing since the bearing was supposed to have been a pressed-
on tight fit which would not slip off of the shaft. The shaft
furnished by the gear manufacturer when replacement parts were
ordered appears to be of a better design.
15
-------
The aeration control system installed in 1968 was intended to alternate
the aerators for mixing of the basin and provide the proper amount of
aeration required during low loading periods on the treatment system.
It incorporated a dissolved oxygen (DO) probe and monitor which pro-
grammed a need for additional dissolved oxygen to the aeration system
on a programming switchboard. This system functioned satisfactorily
and could alternate the aerators on a three hour cycle and call for
additional aerators to be on when the dissolved oxygen in the lagoon
dropped below a preset level. Although this idea has merit from the
standpoint of the saving of aeration power, it may be impractical to
alternate the aerators at this frequency and a longer frequency of
cycling would be advisable from a mechanical standpoint, since
repeated cycling tends to shorten the projected gear life in this
type of equipment according to manufacturer's statements. '
OPERATION OF PROJECT
The project for the study of aeration of fruit processing wastes was
extended over two seasons of operation of the Snokist Growers cannery.
The first season of operation, 1967-1968, began in August, 1967 with
the processing of pears. Peaches were processed in September and
pears were processed again in October until approximately the first
of November. Plums and tomato juice were packed concurrently with
these products. Apple processing began the first of November and
continued with several breaks in processing through May, 1968.
During this season activated sludge treatment was carried out with
aeration in the small existing lagoonj settling in the existing
rectangular hopper bottom clarifier and sludge recirculation from
the clarifier into the aeration basin. The new aeration basin was
operated as an aerated lagoon, with the effluent going directly to
the Yakima River.
The 1968 season saw utilization of the newly constructed clarifier
and return sludge system, in conjunction with the large aeration
basin to which had been installed additional aeration capacity,
as an activated sludge system throughout much of the season. The
season began once again with pears in August and continued through
peaches in September and back onto pears through November 1st.
Once again tomato juice and plums were packed concurrently with
these products. For two weeks prior to the end of the pear season,
the facility was operated as a "contact-stabilization" unit when
sludge reaeration was carried out in the small aeration basin,
prior to its return to the large basin and aeration with the screened
waste. Following the first of November, the system was once again
operated as an activated sludge system with the influent going to
the large aeration basin and sludge recycling from the clarifier
back to the basin. Apple processing which began near the first of
November continued only until approximately December 20 with a one
week break for Thanksgiving in the interim. The short apple crop
of 1968 prompted this shortened season.
16
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'TESTING
Testing procedures for "both 1967-1968 and 1968 processing season
operations were standardized to the greatest extent possible.
Individual data tests were performed as follows.
Flow
Flow was measured as the water passing over a two-foot rectangular
weir with end contractions and the water level going over this weir
was recorded and the flow computed therefrom. During the 1968
processing season, the water level recorder also had a continuous
flow totalizer and read-out so the daily flow from the charts could
"be checked. When the flow was split "between the large and small
"basins, it was done with the use of a divider plate which split
the flow over the rectangular weir. The position of this divider
plate was recorded and the flow to the two "basins computed from
the plate's position and the flow over the weir.
Sample Testing
Laboratory testing of samples collected was done according to
Standard Methods [5 ] for most tests with some exceptions. Appendix
B contains the method of testing for all laboratory tests used
during the study.
1967-19.68 OPERATION
During the 1967-1968 processing season, two methods of treatment of
fruit processing waste by aeration were carried out. The first of
these methods was the so-called aerated lagoon, or aeration without
sludge removal or sludge recycle. The other was aeration with
sludge removal from the aerated waste by settling and sludge
recycle to the aeration basin or the so-called activated sludge
treatment system. Figure 1 shows the schematic flow diagram of
the waste treatment systems as they were operated in 1967-1968.
As it can be seen from Figure 1, the flow following screening on
the vibrating screens was split at the metering box and a portion
sent to the aeration basin of the activated sludge system and the
remainder to' the aerated lagoon. Approximately 18$ of the flow
was diverted to the small lagoon, the activated sludge system,
from approximately August 31 through October k. After October k,
approximately 15$ of the flow was diverted to the small lagoon
for activated sludge treatment until November 1 when the activated
sludge system ceased to receive flow and the entire flow was
diverted to the aerated lagoon. During all of these periods, all
of the flow that did not go to the activated sludge system was
treated in 'the aerated lagoon.
Figure 2 is an aerial photograph of the waste treatment system as
it operated in 1967- Figure 3 shows the flow to each of the two
treatment systems during the 1967-1968 processing season. It also
17
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SCREENED
WASTE
METERING a FLOW
DISTRIBUTION BOX
TO RIVER
1
ACTIVATED
SLUDGE
AERATION
BASIN
CLARIFIER
AERATED
LAGOON
WASTE FLOW
RETURN SLUDGE FLOW - ACTIVATED SLUDGE
FIG. I. - SCHEMATIC FLOW DIAGRAM
1967-1968 PROCESSING SEASON
18
-------
FIG. 2.—TREATMENT FACILITIES 1967-1968 PROCESSING SEASON
AERATED LAGOON, FOREGROUND; ACTIVATED SLUDGE AERATION BASIN,
CENTER WITH RECTANGULAR CLARIFIER BETWEEN BASINS; SCREENING
STATION, METERING AND DIVISION BOX BEYOND SMALL LAGOON; CANNERY
BUILDINGS, TOP.
19
-------
ro
o
2.0-
1.5-
i L0~
o
_i
u.
0.5-
PEAR PEACH
PROC.
PROC.
PEAR
PROCESSING
APPLE
PROCESSING
FLOW TO ACTIVATED SLUDGE BASIN
FLOW TO AERATED LAGOON
20
MBER
fill
10 20
OCTOBER
10 20
NOVEMBER
\
I
10 20
DECEMBER
tc.
UJ
en
o
a:
UJ
o
_i
u.
10 20
JANUARY
1967
I I
10 20
FEBRUARY
1968
10 20
MARCH
FIG. 3. — FLOW - 1967-1968 PROCESSING
SEASON
-------
shows portions of the season during which processing of different
products occurred. Tomato juice packing and plum processing also
occurred during the peach and pear processing portions of the season
tut on an inconsistent "basis.
Aerated Lagoon Performance
Figures U, 5» and 6 show the performance of the aerated lagoon
system in BOD and COD removal and the quality of the effluent
from the aerated lagoon. The data used in plotting these figures
and determining these averages was published in an earlier data
release [6]. Table II contains the average performance of the
aerated lagoon
TABLE II
1967-1968 Aerated Lagoon Performance
Suspended Solids-mg/1 COD-mg/1 BOD-mg/1
Period Influent Effluent Influent Effluent Influent Effluent
Pear Processing 375 77<3 3050 10UO 20UO 370
Peach Processing lU6 830 2150 570 1810 3^0
Apple Processing
(Nov.-Dec.) 62 5^0 1520 760 1230 190
Apple Processing
(Jan.-Feb.) h9 U70 1UOO 620 950 110
Average Lagoon Detention
Time - Days COD Removal-$ BQD Removal-^
Pear Processing 6 66 82
Peach Processing k - 8 73 8l
Apple Processing 12 50 85
(Nov.-Dec.)
Apple Processing lU 56 88
(Jan.-Feb.)
The COD removal efficiency during peach processing is not too reliable
due to a small amount of data and possible discrepancies. The effluent
volatile suspended solids had higher COD than BOD values resulting in
lower COD removal efficiencies.
1967-1968 Activated Sludge
Figures 7» 8» and 9 show the operating performance of the activated
sludge system during the 1967-1968 season. The activated sludge system
was operated during peach and pear processing and then its operation
was terminated until approximately March when the aerated lagoon was
taken out' of service and the entire waste flow from apple processing
put into the small lagoon and an activated sludge system re-established
with the use of the rectangular clarifier and sludge return pumping.
As can "be seen from Figure 7> the BOD removal with activated sludge,
or aeration and return of the sludge to the aeration "basin, was
considerably better than that for the aerated lagoon. It can be seen,
21
-------
4000-
PEAR
APPLE
APPLE
PROC.
PROCESS
PROCESS
3000-
o>
E
l»2000-
o*
6
CD
1000-
o
PROCESS
• = INFLUENT B.O. D.
o= EFFLUENT B.O.D.
— AVERAGE
CONCENTRATION
SEPTEMBER
OCTOBER
NOVEMBER DEC.
JAN.
FEBRUARY
FIG. 4. - 1967-1968 AERATED LAGOON PERFORMANCE-B.O.D.
22
-------
PEACH
PEAR
1
APPLE
APPLE
PROCi
3000-
o>
E
I 2000H
ci
6
o
1000-
PROCESS
PROCESS
PROCESS
• = INFLUENT C.O.D.
o = EFFLUENT C.O.D.
— AVERAGE
CONCENTRATION
-.
0 •
I -|~ |
SEPTEMBER
OCTOBER
i i | i
NOVEMBER DEC.
i | i I
JAN. FEBRUARY
FIG. 5. — 1967-1968 AERATED LAGOON PERFORMANCE-C.O.D.
23
-------
4000-
.PEACH,
PROC.
3000-
o>
E
I
CO
CO
2000-
1000-
o°o °0
PEAR
PROCESS
APPLE
PROCESS
APPLE
PROCESS
o = EFFLUENT VSS
AND MLVSS
— AVERAGE
CONCENTRATION
i i
I T— |W I
SEPTEMBER OCTOBER
i | ' • 4 '
NOVEMBER DEC. JAN.
| 1 1
FEBRUARY
FIG. 6. - 1967-1968 AERATED LAGOON PERFORMANCE- VSS
-------
4000-
3000-
CT
e
i 2000^
ci
d
CD
1000-
PEACH
PEAR
APPLE PROCESS
•= INFLUENT B.O.D.
o = EFFLUENT B. 0. D.
—•AVERAGE
CONCENTRATION
SEPT.
OCTOBER
MARCH
APRIL
i I
MAY
FIG. 7.— 1967-1968 ACTIVATED SLUDGE PERFORMANCE-B. 0. D.
-------
4000-
3000-
o>
E
I 2000-
d
6
d
1000-
PROCESS
PEACH
PEAR
PROCESS
o o
I I
I APPLE PROCESS
SEPT.
1 OCTOBER
• = INFLUENT C.O.D.
o= EFFLUENT C.O.D.
— AVERAGE
CONCENTRATION
MARCH
i r
APRIL
MAY
FIG, 8. — 1967-1968 ACTIVATED SLUDGE PERFORMANCE-C.O.D.
26
-------
4000-
3000-
o>
E
2000-
co
CO
1000-
PEACH
PEAR
APPLE PROCESS
o =
= M LV SS
EFFLUENT VSS
AVERAGE
CONCENTRATION
o
•
08-
00
f-
I I
APRIL
SEPT. OCTOBER MARCH APRIL MAY
FIG. 9.— 1967-1968 ACTIVATED SLUDGE PERFORMANCE- VSS
27
-------
however, that the concentration of BOD in the effluent and as can
"be seen from Figure 8, the concentration of COD in the effluent was
quite erratic, which was due to the erratic sludge removal "by the
clarifier. As the solids in the system "built up and the COD and
BOD loading on the solids decreased, a better effluent resulted.
However, it can be seen from Figure 9 that up until near the end of
the pear processing season, the solids in the clarifier
effluent somewhat followed the amount of solids in the aeration
system and then near the end of pear processing, some sort of upset
conditions resulted in a high carryover in solids into the effluent
from the clarifier. During the apple processing season, that portion
of processing in March showed a relatively good performance by the
system, but the processing during April and May did not develop a
sludge characteristic which readily separated the sludge from the
water in the clarifier and a great deal of sludge carryover was
experienced. A nutrient deficiency may have occurred during that
time. Table III shows a summary of the activated sludge performance.
TABLE III
1967-1968 Activated Sludge Performance
Suspended Solids-mg/1 COD-mg/1 BOD-mg/1
Period Influent Effluent Influent Effluent Influent Effluent
Pear Processing 375 375 3050 U90 20UO 250
Peach Processing lU6 370 2150 700 1810 360
Apple Processing kj U70 1830 570 1390 130
(Mar. -Apr. -May)
COD Removal-^ BOD Removal-^
Pear Processing 8U 88
Peach Processing 67 80
Apple Processing 69 91
(Mar.-Apr.-May)
Here again the COD removal efficiency during peach processing should
not be taken too seriously due to lack of sufficient and possibly
reliable data. The differences in BOD and COD removal can here again
be explained by the difference between the volatile suspended solids
effect in the BOD and COD tests.
Buffering Capacity and pH Control
The buffering capacity of each of the two aeration systems operated
during the 1967-1968 processing season was sufficient that no pH
control was necessary by external means. One of the difficulties with
the system which existed during the 1966-67 season was that during
pear processing the small lagoon which was in use turned quite acid
and required large amounts of lime addition to keep the pH in a suitable
range between 6 and 8. Figures 10 and 11 show that during the 1967-1968
season, both the aerated lagoon and the activated sludge system main-
tained a pH in the aeration basin consistently near 7, regardless of
28
-------
ro
vo
I
CL
12,0-j
10.0-
8.0-
PEAR
PROCESSING
o
.• '
PEACH
PROC.
/**
Q. tf> ^P '
O
PEAR
PROCESSING
>
b •
* •
APPLE
PROCESSING
• INFLUENT-pH
o AERATION BASIN-pH
*** *».
i
APPLE
PROCESSING
-
* •-
o m « + •
^^o5*^ 6<5 ^o ocSbo^P1
o
20
AUG.
FIG. 10. -
i? n
10.0-
8.0-
R n~
10 20 | 10 20 1 10 20
SEPTEMBER OCTOBER NOVEMBER
10 20 | 10 20
DECEMBER JANUARY
- 1967-1968 AERATED LAGOON PERFORMANCE -
PEAR ^
PROCESSIN(
0
20
AUG.
«
^PEAChL
i PROC.
•*.**
,.v
PEAR
PROCESSING
*&%&***>
10 20 I 10 20
SEPTEMBER OCTOBER
•
10 20 |
FEBRUARY
pH
APPLE
PROCESSING
10 20 10 20
MARCH APRIL
fe °0 °o
-
>
10 20
MAY
FIG. II. — 1967-1968 ACTIVATED SLUDGE PERFORMANCE -
H
-------
the influent pH. As it can "be seen, during the pear processing and
apple processing, the waste entering this system was near neutral
"but no acid conditions developed. During peach processing when lye
peeling of the peaches is practiced, the aeration systems "buffered
the pH to practically the same levels as was experienced during other
operational phases of the project.
Nutrient Feeding
Nutrient addition was continued throughout the processing season.
A commercial fertilizer was fed in liquid form and consisted of a
mixture 9-28-0 and 18-0-0. The nutrient feeding was such that the
total nitrogen as N and phosphorus as P in the waste stream to the
treatment systems in relation to the COD were as follows:
Product im/100#COD #P/100#COD
Peaches 3.U O.U8
Pears 3.0 0.3k
Apples lj.,2 O.UT
Sludge Settleability
The settleability of the "biological sludge developed in "both the
aerated lagoon and the activated sludge system was not very good
according to domestic waste treatment standards. However, upon
studying the "biological sludge settleability curves as presented
in Appendix C, it can "be seen that the settleatility definitely
improved with recycling of the sludge from the clarifier to the
aeration "basin as was practiced in the activated sludge system.
Also the settleability of "biological sludge improved with lower
loading imposed "by the apple processing in the aerated lagoon
facility. The indication would "be, therefore, that sludge settle-
ability improves with, (l-) sludge recycling and, (2) increased
sludge detention time, or sludge age in the aeration system. Each
of these results in a lower BOD and COD on the solids. It can "be
seen from the sludge settleability curves that the deterioration
in the effluent quality in the latter part of October from the
activated sludge system can be linked to the deterioration in
sludge into the effluent. The dissolved oxygen in the lagoons
was adequate during this period of time and no change in waste
characteristics being fed to the lagoon was observed. The nutrient
feeding was not noticeably altered during this period of time
although a cumulative deficit of nutrient quantity during pear
processing may have occurred.
Shutdown and Startup
As it has been indicated, there were several periods during the
operating season when the cannery was not operating. This caused
a complete cessation of waste feeding Ijo the treatment system.
During the down time the aerators were kept in operation so the
basins would not go anaerobic. Upon resumption of processing and
30
-------
reintroduction of waste load to the treatment facilities, there did
not appear to be any ill effects upon either waste treatment system
and there didn't appear-to IDC any decrease in efficiency of treatment.
During the down periods, the solids within the aeration "basins
continued to decompose via endogenous respiration. On weekends when
no processing occurred in the activated sludge system, the sludge
settleability improved so that improved treatment efficiency was
experienced during the first part of the following week. This was
due principally to the lowering of the effective BOD and COD loading.
The longer periods of no waste feeding followed "by reintroduction
of the waste at the breaks for Thanksgiving and Christmas didn't
appear to affect the aerated lagoon as solids remained in the system
and "became immediately active. A lengthy shutdown was experienced
in the activated sludge system during April when the sludge settle-
ability appeared to deteriorate "but no explanation is readily available,
Initial startup in either system was done with the "basin full of clean
water and aeration "begun immediately* The dilution prevented high
strength discharge until the "biological systems had "been established
satisfactorily.
Conclusions Drawn at the End of the 1967-1968 Processing Season
Conclusions at the end of the 1967-1968 processing season were:
1. The waste was definitely treatable "by these aerobic
processes and that a high degree of conversion of soluble
organics in the waste to-"biological sludge was obtainable,
2. The biological sludge could be separated and recycled
probably much more efficiently with a properly designed
sludge removal system,
3. The design constants assumed at the beginning of the
project for design of the expanded aeration system did
not contain too great an error in any of the assumptions,
U. Nutrient feeding was definitely necessary and possibly
had some effect on the sludge settleability,
5. The systems had a.dequate pH buffering capacity to level
out any effects of fluctuating pH in the influent and,
additionally, prevent .the formation of acid conditions
in the aeration system. This resulted from the adequate
dilution and complete mixing.
1968 PROCESSING SEASON OPERATION
The 1968 processing season saw the installation of a new clarifier
and sludge return facility. The installation of this equipment,
however, did not become complete until in September which meant
that nearly a month of processing had occurred prior to placement
31
-------
of this equipment into service. During this portion of the season,
the large "basin vas operated as an aerated lagoon. Following the
placement into service of the clarifier and sludge recycle facilities
on September 12, the flow pattern was as schematically portrayed on
Figure 12 and the system acted as an activated sludge system with
aeration and sludge recirculation. During the period from October
16 through November 3, the return biological solids were recirculated
through the small aeration basin prior to their re-entrance into the
large aeration basin. This was the sludge reaeration phase of the
treatment study. Following the end of pear processing on November 3
and apple processing's inception which continued through December 20
when the 1968 processing season study ended, the system was once
again operated as an aeration with simple sludge recycle system.
Figure 13 shows an aerial photograph of the system as it was operated
during the 1968 season. At the time of this photograph, sludge
recycle through the small basin was not taking place, and, therefore,
the mixed liquor suspended solids in the large basin was at a higher
level than that in the small aeration basin.
Flow
The flow to the treatment system being studied during 1968 processing
season is shown on Figure lU. On several days during the operating
season a portion of the flow was bypassed and is not included on
this flow chart. This occurred primarily at the very start of the
season in middle and late August, during the first few days of peach
processing, just prior to the placement into operation of the clarifier
and sludge pumps and again at the beginning of the pear processing
season which followed peach processing. These bypass periods occurred
due to the necessity of lower flow going into the system during the
construction operations but did not materially effect the study as
it was being carried out since the bypass portion of the flow was
eliminated from the calculations and testing results.
Testing Results
The performance of the treatment system during the entire season of
operation is shown on Figures 15, 16, and IT with regard to BOD and
COD removal, and volatile suspended solids in the basin and in the
effluent. The BOD removal through the treatment system is shown on
Figure 15 with an average line also shown with the data. As it can
be seen, during the. aerated lagoon portion of the treatment during
pear processing, approximately the same removal of BOD and COD was
experienced as the previous year. During peach processing, the
sludge recirculation phase was Just beginning to cause MLVSS buildup
and the BOD and COD removal improved during the entire peach pro-
cessing area as a result of increased removal of volatile suspended
solids from the effluent as the sludge settleabilrfy improved.
Activated sludge treatment of pear processing waste saw excellent
BOD and COD removals almost 99$ of the time. The apparent increase
in screened waste strength during pear processing following the peach
processing is primarily a result of lowering of the process flow as
32
-------
SCREENED
WASTE
METERING S FLOW
DISTRIBUTION BOX
TO RIVER
SLUDGE
RE AERATION
BASI N
CLARIFIER
AERATION
BASIN
WASTE FLOW
RETURN SLUDGE FLOW - ACTIVATED SLUDGE
RETURN SLUDGE FLOW - ACTIVATED SLUDGE - WITH
SLUDGE REAERATION
FIG. 12. -
SCHEMATIC FLOW DIAGRAM
1968 PROCESSING SEASON
33
-------
FIG. 13. — TREATMENT FACILITIES 1968 PROCESSING SEASON
AERATION BASIN, RIGHT FOREGROUND; CLARIFIER AND SLUDGE PUMP
BUILDING, CENTER BETWEEN LAGOONS; SMALL LAGOON USED FOR
SLUDGE REAERATION PORTION OF SEASON; SCREENING STATION
AND METERING BOX BEYOND SMALL LAGOON; CANNERY BUILDINGS
UPPER LEFT; LABORATORY IS SMALL BUILDING BETWEEN MAIN
CANNERY BUILDINGS AND WAREHOUSE.
-------
2.5-
2.0-
§ 1.5-
S
i
$
o
u_
0.5-
0-
PEAR PEACH
PROCESSING
L|
1
r
I
1
PROC.
V
1 i
in ?n
If
•L
f.
r
1
[
1
PEAR APPLE
PROCESSING
n.
r
in ?n
11 |
r|J
1
rd
U
I
PROCESSING
A
H
L
A
fill Jf
r I
in ?n in ?n in 9n
AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER
>968
FIG. 14. - FLOW -1968 PROCESSING SEASON
35
-------
4000-
3000-
o>
E
I
o
6
CD
,2000-
1000-
PEAR IPEACH
PEAR
PROCESS pROCESq PROCESS
AERATED ACTIVATED SL. RE-
LAGOON
SLUDGE
AERATION
T
APPLE
PROCESS
ACTIVATED
SLUDGE
• = INFLUENT B.O.D.
0= EFFLUENT B.O.D.
"~ AVERAGE
CONCENTRATION
•T
\
AUGUST SEPTEMBER OCTOBER
NOVEMBER
DECEMBER
F|6 |5> __ |968 TREATMENT SYSTEM PERFORMANCE-B.O.D.
36
-------
4000-
3000-
E
i
Q
6
d
. 2000-
1000-
T
_ PEAR
PROCESS
AERATED
PEAR
ESS PROCESS
ACTIVATED SL. RE-
LAGOON
AERATION
SLUDGE
• = INFLUENT C.O.D.
o= EFFLUENT CO.D.
^ AVERAGE
CONCENTRATION
APPLE
PROCESS
ACTIVATED
AUGUST SEPTEMBER
OCTOBER NOVEMBER DECEMBER
FIG. 16. — 1968 TREATMENT SYSTEM PERFORMANCE-C.O.D.
37
-------
4000
3000-
o>
E
2000-
co
CO
1000-
PEAR PEACH
PROCESS
AERATED
PROCESS
ACTIVATED
PROCESS
ACTIVATED SL RE-
• = MLVSS
o= EFFLUENT VSS
AVERAGE
CONCENTRATION
AUGUST SEPTEMBER OCTOBER
NOVEMBER DECEMBER
FIG. 17. - 1968 TREATMENT SYSTEM PERFORMANCE-VSS
-------
can "be seen from Figure lU during that time, so that the actual
pounds of BOD load to the system did not fluctuate greatly. During
apple processing the removal of BOD and COD through the treatment
system remained excellent even though the influent waste load was
considerably lower. The sludge reaeration during pear processing
did not show a great increase in efficiency above that of the regular
activated sludge or aeration with simple sludge recycle, however, it
is difficult to note changes in effiency during periods when removal
efficiencies are as high as was experienced. The superiority of a
well designed clarification system can be seen by the comparison of
activated sludge results with the previous year. During peach processing
and when the sludge recirculation to the aeration basin was operating,
the sludge improved in settleability characteristics, due to the lower
BOD and COD loading per unit weight of sludge and ultimately little
solids carryover was experienced to raise the COD or BOD. Table IV
contains a summary of treatment results.
TABLE IV
1968 Processing Season Treatment Results
Suspended Solids-mg/1 COD-mg/1 BOD-mg/1
Influent Effluent Influent Effluent Influent Effluent
Pear Processing 290 6UO 2870 1050 2080 U60
(Aug.-Sept. 7)
Aerated Lagoon
Peach Processing 110 520 1510 710 860 115
(Sept.9-Sept.lU)
Aerated Lagoon &
Activated Sludge
St artup
Peach Processing 110 66 1510 120 860 20
(Sept.l6-Sept.2l)
Activated Sludge
Pear Processing 290 15 2290 55 1600 9
(Sept.23-0ct.l6)
Activated Sludge
Pear Processing 290 6 2910 23 2150 U
(Oct.l7-Nov.3)
Activated Sludge
with Sludge Re-
aeration
Apple Processing 55 H 1500 28 1190 5
(Nov.5-Dec.)
Activated Sludge
COD Removal-^ BOD Removal-^
Pear Processing - Aerated Lagoon 63 78
Peach Processing - Aerated Lagoon 53 86
and Activated Sludge
Peach Processing - Activated Sludge 92 97+
Pear Processing - Activated Sludge 97+ 99+
Pear Processing - Activated Sludge 99 99+
and Sludge Reaeration
Apple Processing - Activated Sludge 98+ 99+
39
-------
Figure IT shows the volatile suspended solids concentration of the
effluent from the treatment system and in the aeration basin separately
where they were different. As it can he seen, the volatile suspended
solids concentration in the effluent increased during the aerated
lagoon method of treatment of the waste during pear processing and
began to drop off slightly as peach processing started and prior
to the inception of sludge recycling. Following the "beginning of
sludge removal and recycling with the clarifier and recycle pumps ,
the concentration of volatile suspended solids in the effluent decreased
rapidly and in approximately a week began to level off with a very small
amount of volatile suspended solids in the effluent. The mixed liquor
volatile suspended solids concentration increased steadily following
the beginning of sludge recycling due to little sludge wasting until
the beginning of sludge reaeration, at which time a lower concentration
of solids was carried in the aeration basin and although the total
weight of solids in the system remained the same this lower concen-
tration persisted until the beginning of apple processing, at which
time the solids level began to decline due to the lower feed rate of
organic material. Intentional wasting of solids in small amounts was
done only once or twice during the season. There was a small continuous
wastage at one. bypass gate during activated sludge treatment. A
larger leak was present in the sludge reaeration basin during contact
stabliHzation treatment. Both of these leaks were measured and the
sludge wastage computed for use in later computations. The results
of laboratory testing during the 1968 processing season are contained
in a data release covering that season ['?]•
The pH of the treatment system as operated in the 1968 processing
season exhibited much the same characteristics as were seen during
the 1967-1968 season. The aeration system displayed the ability to
buffer the pH of the contents within a very narrow range and the
range which is considered acceptable for biological treatment
regardless of the incoming waste pH although no acid wastes were
discharged to the system. During peach processing the lye peel
practice resulted in highly alkaline waste being introduced to
the aeration basin which had no adverse effect on the aeration
basin contents. Figure 18 shows the pH of the influent and of
the aeration basin during the 1968 processing season.
Nutrient Feeding
During the 1968 processing season, the nutrient feeding schedule
was changed somewhat from that practiced during the 1967-1968
season. Nitrogen and phosphorus in the form of 9-28-0 were fed
to the system to provide the amount of phosphorus required. The
additional nitrogen required was fed in the form of 29-1-0-0 which
contained predominately NH- nitrogen and a smaller proportion of
NOo nitrogen than the 50$ of each contained in the 18-0-0 fed during
the previous season.
-------
14.0-
12.0-
10.0-
x
Q.
8.0-
6.0-
i
PEAR
PROCESSING
AERATED
LAGOON
•
A**V
o
1 1
10 20
PEACH
F
4
%
£°°
3ROC.
A
to**
**
^019*
i
PEAR
PROCES
CTIVATED
SLUDGE .
ff$M
i i
10 20
•
••
^OBD^
*
SING
SL. RE-
AERATION
f %*
APPLE
PROCESSING
ACTIVATED
SLU
DGE
• = INFLUENT pH
o = AERATION BASIN pH
•
?b(ftcC3<<«"i
^1 fr Jfp
-
-
10 20
AUGUST
SEPTEMBER OCTOBER
NOVEMBER DECEMBER
FIG. 18. — 1968 TREATMENT SYSTEM
PERFORMANCE - pH
-------
The nutrient fed during this season was such that the nitrogen and
phosphorus in the influent to the treatment system vere in relation
to the COD as shown following:
Date Product #N/100#COD #F/100#COD
Aug. 19-31 Pears U.2O.U9
Sept. 3-7 Pears 3-9 0.80
Aug. 9-20 Peaches 5.3 1.13
Sept.21-Nov.2 Pears 3.6 0.73
Nov. 5-20 Apples 2.1 O.U7
The reason for the reduction in nutrient feed ratio during apple
processing from what had been previously practiced was the amount.
of residual nutrient in the treatment system as compared to the
influent organic load in the apple processing waste and the nutrient
being released from the existing biological sludge as it was broken
down by endogenous respiration.
Sludge Settling Characteristics
The settling curves gathered during the 1968 processing season .are
contained in Appendix C following those gathered during the 1967-
1968 processing season. As can be seen from these settling curves,
the sludge from the aerated lagoon treatment settled rather well
initially and then decreased slightly in settleability prior to the
inception of sludge recycling. It must be noted here however, that
considerable suspended solids remaiied in the supernatant in the
form of "deflocculated" sludge during this period. Following the
beginning of sludge recycling, the settling curves did not indicate
very good settling characteristics although the settled suspended
solids were increasing steadily following the beginning of sludge
recycling. The settling characteristics of the sludge became
somewhat better as the amount of biological solids in the system
increased and the COD loading on the system therefore decreased.
In addition, the supernatant began to contain less and less
deflocculated sludge as the MLSS concentration increased. By the
time of the sludge reaeration phase of treatment, the settleability
became quite acceptable as compared to previously, and the super-
natant contained nearly no suspended solids although the rate of
settling still did not nearly equal that normally experienced in
a domestic activated sludge system where it is expected to get
nearly complete settling within the period of approximately an hour
and little settling following that. The sludge settling character-
istics during December more nearly followed that which would be
expected from a domestic treatment activated sludge except for not
achieving the degree of compaction normally observed there. The
supernatant continued to contain nearly no suspended solids. The
loading rate of COD on the volatile suspended solids during this
time was quite low however.
-------
The clarity of the effluent from the clarifier vas very good during
the late pear processing season as can be seen on Figure 19 and
continued throughout the rest of the 1968 season.
Startup
Startup of the activated sludge system from an aerated lagoon
resulted in several days of operation when considerable solids
were lost over the clarifier weir because of poor settleability.
The startup of the aerated lagoon system resulted in an effluent
BOD and COD which started out at approximately the dilution values.
The BOD decreased while the COD increased with the development of
active organisms. Future startups will probably combine these two
characteristics and it may take two weeks of operation before
establishment of optimum treatment at the beginning of each
processing season. Short duration shutdowns when the sludge mass
can be retained in an active state should not result in effluent
deterioration. This was observed during the Thanksgiving shutdown.
DISCUSSION
WASTE LOAD
The cannery on which this study was run processes fruit grown in
the Yakima Valley area into canned product. During each season,
the cannery processed pears and peaches during separate seasons and
concurrently canned tomato juice and purple plums. Following the
end of the pear processing season, approximately the first of
November- apples were processed into applesauce, apple slices and
apple rings on through the winter months. The 1968 season saw a
reduced apple crop in the local area and on approximately the
20th of December the apple processing season ended. Although some
apples came out of storage later during the winter, their quantity
was not sufficient for the study to continue and the study was
ended in December, 1968.
During the study, raw waste flows from the process were recorded
and tested for BOD and COD content following screening over 20 mesh
vibrating screens. Production figures were available from the
cannery during the processing season and unit waste load contri-
butions have been computed therefrom. The capacity of the cannery
for both pear and peach processing is approximately 250 tons of raw-
product per two shift day. Approximately 150 tons of tomatoes can
be processed during a two shift day concurrently but this figure is
seldom reached due to the availability of raw product, and the
processing day is adjusted according to the raw product available.
Approximately 50 tons of plums can be processed concurrently with
the peaches and pears on a two shift basis. The cannery's capacity
for apple processing depends on the products produced but is generally
approximately 100 tons per two shift day.
-------
FIG. 19. - CRYSTAL CLEAR CLARIFIER EFFLUENT
DURING 1968 PROCESSING SEASON.
-------
The unit waste loads contributed during the processing seasons have
been computed and averaged. The unit waste flows during process and
the standard deviations in the flow have been determined to be
approximately as follows:
Flow - gal/ton Standard Deviation
Product Raw Product gal/ton Raw Product
Pears
Peaches
Purple Plums
Tomato Juice
Apples
5800
7500
7000
3200
8200
The chemical oxygen demand (COD)
processed were as follows:
Product
Pears
Peaches
Purple Plums
COD - #/Ton
Raw Product
105
98
95
800
1000
1000
500
2600
contribution of the products
Standard Deviation
#/Ton Raw Product
13
15
15
Tomato Juice Negligible Compared to concurrent
products being run
Apples 71 18
-------
The "biochemical oxygen demand (BOD) contribution during the waste study
period was as follows:
BOD - #/Ton Standard Deviation
Product Raw Product #/Ton Raw Product
Pears 78 10
Peaches 66 10
Purple Plums 6k 10
Tomato Juice Negligible Compared to other
products being processed
Apples 53 lU
The ratio of BOD concentration in the raw screened waste compared
to the COD in the raw screened waste varied somewhat between products,
On the 1967-1968 processing samples, the BOD's were run on canned
preserved samples in many instances. The correlation between BOD
and COD on the fresh samples from these canned samples was not
different from the correlation between BOD and COD, both taken on
the raw samples for other times during that season and during the
1968 season. The correlation was greater than 80$ on the "t" series
between the two sets of data. The BOD to COD ratios in the raw waste
among the separate products during this study were as follows:
Standard
Product BOD over COD Deviations
Pears 0.7U 0.09
Peaches 0.67 0.10
Apples 0.75 0.07
The quantities of nutrient in the raw waste are insufficient for
biological treatment according to standards generally accepted.
The amount of nitrogen and phosphorus in the raw waste stream
varied slightly between products processed. The nitrogen and
phosphorus are computed as a ratio to the BOD and COD concentration
in the waste stream to be more meaningful. Prior to any nutrient
addition, the nitrogen and phosphorus in the raw waste following
screening were as follows:
H N_ P_ P
Product BOD COD BOD COD
*
Pears 0.006 O.OOU 0.0012 0.0009
Peaches 0.011 0.007 0.0027 0.0016
Apples 0.0023 0.0017 0.0010 0.0008
-------
COST OF TREATMENT
Cost of treatment consists of the cost of the construction of
facilities and the annual cost of operation and maintenance.
A breakdown of each of these costs as experienced to date on the
project are included in Appendix A, Tables A-l, and A-3. Table V
contains a summarization of these costs included in the appendix
and, in addition, breaks down the construction cost of facilities
into an annual charge based on amortization over 20 years , assuming
that money for construction was borrowed at 1% interest. An average
of $UO,000 for the annual cost of operation and maintenance was taken
and a $5,000/year cost of major improvements and equipment replace-
ment and repair was assumed to add to the $51,300/year annual
amortization charge for construction. This makes a total annual
charge of $96,300 per year for the treatment facility.
During.the 196? season, approximately 2,077,000 pounds of COD were
in the screened waste going to the waste treatment system. During
the same season, approximately 1,523,000 pounds of BOD were in the
screened waste. The 1968 processing season saw approximately
1,997,000 pounds of COD and 1,U6U,000 pounds of BOD in the screened
waste going to the treatment system. Based on an average of
2,000,000 pounds of COD and 1,500,000 pounds of BOD per operating
season, the cost of treatment of the waste is approximately U.8<£
per pound of COD and 6.U^ per pound of BOD discharged to the waste
treatment facility. Based on the treatment cost per pound of COD
the treatment cost per ton of raw product for pears, peaches,
purple plums, and apples is also shown on Table V.
TABLE V
COST OF WASTE TREATMENT - TOTAL SYSTEM
Total Cost of Construction $5^3,158
Amortization Factor 20 years % 1% Interest 0.09^
Annual Cost of Construction 51,300
Annual Cost of Operation & Maintenance H0,000
Approximate Annual Major Improvement 5 ,000
or Equipment Replacement & Repair
Annual Cost of Waste Treatment $ 96,300
Annual Waste Load COD = 2 x 106 #
BOD = 1.5 x 106#
Approximate Cost of Treatment $O.OU8/#COD Added
0.06U/#BOD Added
Pears ' $5-00/Ton Raw Product
Peaches U.70/Ton Raw Product
Purple Plums U.50/Ton Raw Product
Apples 3.HO/Ton Raw Product
1*7
-------
Since aerated lagoon treatment provides only TO to 80 percent reduction
in BOD and leaves a high suspended solids load in the effluent, whereas
activated sludge treatment with or without sludge reaeration provides
nearly "complete biological or secondary treatment", it would seem
advisable to compare the alternatives more thoroughly.
Taking the costs as presented in Appendix A and choosing only those
applicable as a "basis for estimating, a cost figure can be gotten for
each of the three- methods of treatment employed. Table VI contains
estimates of treatment costs for the waste load for each of the three
treatment methods separately. The construction costs include an
increase of 10 percent above what was experienced at Snokist in an
attempt to offset inflation and engineering design and construction
services at a rate of 12 percent. No nutrient savings are considered
between treatment methods but a saving in both power cost and operation
and supervision costs are considered for the aerated lagoon operation
over the other two.
TABLE VI
ESTIMATED COSTS OF SEPARATE METHODS OF TREATMENT
Construction Costs
Annual Cost of Construction
(20 years % 1% Interest)
Power Cost
Nutrient Chemicals
Operation and Supervision
Maintenance, Labor & Materials
Laboratory Supplies
Major Repairs & Improvements
Annual Cost of Treatment
Assumed % COD Removal
Aerated Lagoon
$205,000
19,^00
7,000
10,500
6,000
1,500
1,500
3,000
$ U8,900
COD
Costs
Assumed
2xlOD#CODx$ Rem.
BOD Removal
Costs
B-.
$ 0.035/
#COD Rem.
80%
$ 0
#BOD Rem.
Activated Sludge
Without Sludge With Sludge
Reaeration Reaeration
,000
,UOO
10,000
10,500
12,500
2,000
2,500
5,000
$ 86,900
90$
$ O.OU8/
#COD Rem.
95$
$ 0.061/'
#BOD Rem.
$557,000
52,600
10 ,000
10,500
12,500
2,000
2,500
5,000
$ 95,100
$ 0.053/
#COD Rem.
$ 0.067/
#BOD Rem.
As can be seen, the aerated lagoon provides a considerable cost saving
over the nearly complete biological treatment offered by the activated
sludge or activated sludge with sludge reaeration. Of course, the
aerated lagoon treatment is probably not adequate to permit release
of the waste into the environment but would lower the load considerably
on a municipal treatment plant if the cannery discharged to a municipal
-------
sewage system. It could make lagooning in facultative lagoons
following the aerated lagoon feasible in more remote locations
with adequate land availability. The aerated lagoon effluent
contains suspended solids in excessive amounts as compared to
domestic waste and this would have to "be taken into consideration.
An additional cost factor is not included in Table VI for either
of the complete secondary treatment schemes. This is the cost of
waste sludge disposal, since this project did not adequately evaluate
costs along this line. The thickening by equipment included in this
project will probably be good to only 3 to U percent solids on a dry
weight basis. Their further dewatering and subsequent disposal or
disposal in this relatively wet state needs further investigation.
A comparison can be made between costs estimated here and those
estimated in a recent publication of the California Water Resources
Control Board concerning cannery waste treatment [8]. In that
publication cost estimates were made for treatment of a waste much
weaker than those experienced in this study but by adjusting flows
the cost estimates should be comparable. For aerated lagoon treat-
ment the California publication has estimates for an 8 MGD flow with
a COD of U50 mg/1. This would be equivalent to l.UU MGD at 2500
mg/1 or roughly what was experienced on this project. They indicate
(p. 15U) that roughly 5 days detention time is required to achieve
80 percent BOD removal but taking this detention time at higher
concentration and less flow would decrease the capital cost of
construction to approximately what they have computed for 1.2 days
detention time. The annual 0 & M costs for 80 percent removal would
not change.
Capital Cost $222,600
20 Years at 1% 21,000
Annual 0 & M Costs 68,130
Total Annual Costs $ 89,130
As can be seen, it is primarily in the annual 0 & M estimate where
the cost estimated differs with that estimated from this project
(see Table VI).
The estimate for activated sludge treatment made by the California
Water Resources Control Board Report can be taken nearly directly
for the 8 MGD flow at U50 mg/1 COD since flow has less impact on the
capital expenditure. However, the figures for 89.5$ BOD removal
efficiency will be used for comparison.
Capital Cost $550,000
20 Years at 1% 51,900
Annual 0 & M Costs 58,UOO
Total Annual Costs $110,300
-------
The figure derived is slightly higher in each capit 1 cost and 0 & M
than the costs estimated from the experiences of this project (see
Table VI).
SUBSTRATE REMOVAL
Substrate, or soluble COD and BOD, removal from the waste stream
was presented in theory earlier and equations (l) and (2) set up
to describe the function. Equation (2)
R = f s (2)
is the most easily evaluated equation since it involves a straight
line relationship with the origin at the axis when R and s are
plotted. Considerable data was collected on substrate removal rate
and remaining substrate concentration during the course of this
study. Considerably more data on COD removal rate and soluble
COD remaining was collected than was data on BOD removal rate
and BOD remaining. Figures 20 through 26 show the COD removal
rate versus the soluble COD remaining in the effluent. Since
each of the aeration systems used was considered a completely
mixed system, the soluble COD in the effluent was the COD in the
aeration basin upon which the organisms had to react. These figures
are divided up according to product being processed and the temper-
ature of the aeration basin during the period which data was collected.
As can be seen, the slopes of the lines drawn through the axis of the
plot and through the data at the median data point varies between
the plots. It can be observed that the slopes of these lines vary
approximately according to the temperature of the aeration basin
with the exception of the pear processing activated sludge with
sludge reaeration or contact stabilization as shown on Figure 23.
This contact stabilization system would not be expected to follow
the same reaction kinetics in this respect as the completely mixed
systems without sludge reaeration prior to reintroduction into the
aeration system, since the entire biological mass does not have the
same substrate level from which to continuously work. The entire
VSS in the system was used to compute the COD removal rates. All
of the data on Figure 20 was collected during aerated lagoon operation.
Data on Figure 2k was collected during aerated lagoon and activated
sludge treatment of the waste. Figures 21, 22, 25, and 26 contain
data from activated sludge operation.
Figure 27 contains a plot of the slope as plotted on the previous
figures 20 through 26 versus the temperature in the aeration basin
in degrees centigrade. . As can be seen, a straight line plot can be
obtained when the COD removal coefficient is plotted on semilogarlthmic
scale. From Figure 27 equation (10) which is a form of the Arrhenius
equation [2j can be derived which establishes the COD removal rate
for this fruit processing waste in a completely mixed aeration system.
This formula ignores differences between products being processed.
fm = 0.017 x 1.16(T-20) (10)
50
-------
PEAR PROCESSING
TEMPERATURE=I7- I 8°C.
MEAN TEMP.= 17.7° C.
60
80
100 120
C. 0. D. - mg / I
140
160
180
200
FIG. 20. — C.QD. REMOVAL RATE VS CONCENTRATION
-------
ro
Q
I
01 0.4-
E
Q
C)
o 0.3-
o>
E
I
UJ
0.2-
0.1-
q
O
o"
10
o
o
0.0076
o
o
i
20
i
30
i
40
r
50
PEAR PROCESSING
TEMPERATURE =I3°-I6°C.
MEAN TEMR = 14.6° C.
60
C. 0. D. - m g / I
FIG. 21. - C.O.D. REMOVAL RATE VS CONCENTRATION
-------
V/l
U)
I
CO
CO
o»
^ 0.4-
ci
q
d
o» _ _
E 0.3-
UJ
2 0.2-
cc
d
c>
d
0.1-
10
0.006
\
20
30
i
40
i
50
o
PEAR PROCESSING
TEMPERATURE= lO^IZ
MEAN TEMP = 11.1° C.
60
C. 0. D. - mg / I
FIG. 22. - C.O.D. REMOVAL RATE VS CONCENTRATION
-------
V/l
-1=-
O
i
w
(O
0.4-
o
O
o
Ul
I-
<£
(C
0.3-
0.2-
Ul
a:
0.1-
r
10
0.0103
20
i
30
40
PEAR PROCESSING -
ACTIVATED SLUDGE WITH
SLUDGE REAERATION
TEMPERATURE= 8.5°-ll°C.
MEAN TEMP. = I0.2°C.
50
C 0. D. - m g / I
FIG. 23. - C.O.D. REMOVAL RATE VS CONCENTRATION
-------
V/I
VJ1
0.8-
0.7-
0.6-1
>-
<
CO
CO
0>
E
v.
cj 0.5H
o
d
o> 0.4-
E
Id
h-
UJ
0.3-
0.2-
0.1-
o 0
0
o
20
40
0.0109 ©
0
0
PEACH PROCESSING
TEMPERATURE = 14-I8°C.
MEAN TEMP. = 16° C.
60
80
100
C. 0. D. - mg/l
120
FIG. 24. — C.O.D. REMOVAL RATE VS CONCENTRATION
-------
O\
<
Q
CO
CO
Q
C>
d
o»
E
i
tu
0.1-
0.05-
o
6
o
o
o
o
10
0.0026
APPLE PROCESSING
TEMPERATURE= 6°-8.5°C.
MEAN TEMP. = 7.0° C.
i
20
30
C. 0. D. - mg / I
FIG. 25.- C.O.D. REMOVAL RATE VS CONCENTRATION
-------
V/l
—1
O
i
0)
O)
o
O
o
o>
E
i
Ul
0.1-
O
a
q
6
0.05-
o
0
APPLE PROCESSING
TEMPERATURE=2°-5° C.
MEAN TEMP. 3.7° C.
J 0.0015
20
C. 0. D. - m g / I
i
30
FIG. 26. — C.O. D. REMOVAL RATE VS CONCENTRATION
-------
o
d
o>
Q
I
0.02-
co 0.01-
o> 0.008-
E
o
E
I
Ul
o
iZ
u.
UJ
o
o
2
O
2
UJ
O
O
d
i
0.006-
0.005-
0.004-
0.003-
0.002-
QOOI
fT s 0.017 x 1.16
T-20
I
5
LOG" 0.064= 1.16
© PEAR PROCESSING
Q PEACH PROCESSING
a APPLE PROCESSING
© PEAR PROCESSING-
ACTIVATED SLUDGE WITH
SLUDGE REAERATION
10 15
20
TEMERATURE - °C.
FIG. 27. -G.QD. REMOVAL COEFFICIENT VS TEMPERATURE
-------
fT = COD Removal Coefficient at T° C
T = Temperature °C
If there can be assumed a consistent ratio of influent BOD to COD
and a consistent ratio of effluent soluble (or substrate) BOD to
COD, then the removal coefficient for BOD would follow a temperature
dependence curve of the same slope as the COD removal coefficient.
Therefore
f = f x 1 16(T-20)
JBODT BOD2Q x -1--10
where
fBOD = BOD removal coefficient at temperature T° C
fBOD = BOD removal coefficient at 20° C
311(1 XT-20)
"D — .p a . .p TT^* '
\BOD BOD ^20
R = BOD removal rate = mS Bfgp?BBOT8d
BOD mg MLVSS-day
it follows that
fBOD2Q S = RBOD 1'1~
By taking what BOD data is available and adjusting it according to
this equation and plotting (Figure 28), a value for fgQD can te
obtained. This results in 20
fBOD = 0.068 x 1.16(T-20)
T
The curve on Figure 28 was plotted through the median value not
considering the points resulting from pear processing activated
sludge with sludge reaeration.
BIOLOGICAL GROWTH
As it was pointed out earlier and according to the equations (3)
and (5), the sludge growth is directly proportional to the BOD or
COD removed and the net sludge growth is the sum of the sludge growth
and the endogenous respiration which is a negative number. The
constants in the sludge growth equation can be determined by plotting
the net sludge growth in milligrams of volatile suspended solids
produced per milligram mixed liquor volatile suspended solids/day
versus the BOD or COD removal rate in milligrams of BOD or COD per
milligram of MLVSS-day. During the project considerably more data
was collected on COD removal rates due to the excessive length of
time taken to run BOD tests than was BOD data. As it was pointed
59
-------
UJ
oc
Q
6
DO
1.0-
CO
(/)
Ot
E
t-
I
o
CM
a\
o
<0
0.5-
0
o
CD
i
10
0.068 x 1.16
(T-20)
mo B.O.D. REM
ing M.L.V.S.S. - DAY-mg/l
PEARS-AERATED LAGOON
© PEARS-ACTIVATED SLUDGE
O PEARS-ACT. SL. W/SLUDGE REAERATION
HJh PEACHES-AER. LAGOON 8 ACT. SLUDI3E
A APPLES-ACTIVATED SLUDGE
I
20
SUBSTRATE B.O.D. - mg / I
FIG. 28 - B.O.D. REMOVAL RATE VS CONCENTRATION AT 20° C.
-------
out earlier, the "biological growth, or sludge growth, was measured
as volatile suspended solids during the project.
The net sludge growth was plotted versus the COD removal rate
according to the product "being processed. It was noted that a
wide range existed in some of these plots so each of these was
plotted once again according to temperature of the aeration "basin
during the operation. This separation according to temperature
yielded plots which had a constant slope for a given product "being
processed, but which had different intercepts on the axis, thereby
giving a different endogenous respiration rate constant. The slope
of the curve is the sludge growth constant. Figures 29 through 3U
contain the plots of net sludge growth versus COD removal rate and
are divided according to product "being processed and the temperature
in the aeration basin. As can be seen, Figures 29, 30, and 31 s
which all resulted from pear processing, contain the same slope to
the plot but different intercepts on the net sludge growth axis.
Figure 32 was plotted utilizing the same slope since the product
being processed was the same in order to determine the intercept
for that method of processing and temperature. The COD removal
rate for Figure 32 was computed using total VSS in the system.
Figure 33 for peach processing obtained a slightly different slope
and intercept than was experienced on the pear processing figures
while Figure 3h obtained a slope for apple processing which was
quite different from that for either pears or peaches. Although
purple plums were run during the peach and pear processing season,
their volume was so small in comparison to the peach or pear volume,
the constants here are assumed to be for the major product processed
at the time. On Figure 3^ a further breakdown of data according to
temperature did not separate the lines sufficiently to make it
worthwhile.
In equation (5) the slope of the curve from these plots is c_, sludge
growth constant and the intercept is k_, the endogenous respiration
rate.
G = c R - k (5)
The endogenous respiration rates established from the net sludge
growth versus COD removal rate plots were plotted versus temperature
in degrees centigrade on Figure 35- The endogenous respiration rate
when plotted on a semilogarithmic scale versus the temperature on
arithmetic scale shows a straight line relationship according to
temperature and once again follows a form of the Arrhenius equation
[2], This relationship, equation 11
k^ = 0.115 x l.ll*(T-20) (11)
km = Endogenous Respiration Rate at Temperature T-°C
gives endogenous respiration rate for the volatile suspended solids
measurement of biological solids grown on the fruit processing waste
61
-------
to
>_
a
(O
0.6H
0.5-
S 0.4 H
0.3-
o
©o
o
o
^T 0.49
PEAR PROCESSING
TEMPERATURE = 16°-19° C.
MEAN TEMP = I7.5°C.
o 1968 AERATED LAGOON
Q 1967 ACTIVATED SLUDGE
i
1.2
i
1.4
0.2 0.4 0.6 0.8 1.0
C.O.D. REMOVAL RATE - mg C.QD. / mg MLVSS - DAY
FIG. 29.-NET SLUDGE GROWTH VS C.O.D. REMOVAL RATE
-------
ON
U)
0.6H
>-
<
o
i
co 0.5-
co
o>
E 0.4-
co
co
o>
E
0.3-
0.49
PEAR PROCESSING
TEMPERATURE = I3°-I6°C.
MEAN TEMP. = 14.2° C.
o1968 ACTIVATED SLUDGE
GJ 1967 ACTIVATED SLUDGE
& 1967 AERATED LAGOON
0.4 0.6 0.8 1.0 1.2 1.4 1.6
C.O.D. REMOVAL RATE - mg C.O.D. / mg MLVSS- DAY
.8
FIG. 30.-NET SLUDGE GROWTH VS QO.D REMOVAL RATE
-------
ON
O
I
(0
CO
>
o»
E
i
X
o
QC
0.4-
0.3-
0.2-
0.49
PEAR PROCESSING
TEMPERATURE = \0*-12.5C C.
MEAN TEMP. =10.8°C.
o 1968 ACTIVATED SLUDGE
0 1967 ACTIVATED SLUDGE
& 1967 AERATED LAGOON
i i i
0.2 0.4 0.6
C.O.D. REMOVAL RATE -
0.8 1.0
mg C.O.D. /mg MLVSS- DAY
FIG. 31.- NET SLUDGE GROWTH VS C.O.D. REMOVAL RATE
-------
V/1
CO
CO
o>
E
x.
CO
CO
i
I
o
IU
C9
O
0.2-
0.1-
0.49
PEAR PROCESSING
TEMPERATURE = 8.5°-11.5° C.
MEAN TEMP. = IO.I°C.
© 1968 ACTIVATED SLUDGE WITH
SLUDGE REAERATION
0.2 0.3 0.4
C.O.D. REMOVAL RATE - mg C.O.D./mg MLVSS-DAY
FIG. 32.-NET SLUDGE GROWTH VS C, 0, D. REMOVAL RATE
-------
>-
<
o
CO
CO
0.5-
o» 0.4
E
CO
CO
o> 0.3-
2 0.2-
CO
UJ
o
0.1-
CO
I-
Ul
o o
O
o
o
0.46
PEACH PROCESSING
TEMPERATURE = 13° - 18° C.
MEAN TEMP. = 15.7° C.
© 1968 ACTIVATED SLUDGE
0.065 ^T
0.2 0.4 0.6 0.8 1,0 1.2 1.4
C.O.D. REMOVAL RATE - mg C.O.D./mg MLVSS - DAY
1.6
FIG. 33.-NET SLUDGE GROWTH VS C.O.D. REMOVAL RATE
-------
CO
CO
0>
E
S 0.2-
I
h-
£
O
cr
UJ
o
o
3
_i
CO
0.1-
o
o
0
W0
O G> O
O
^0.57
APPLE PROCESSING
TEMPERATURE = 2°-IO°C.
MEAN TEMP. = 6.1° C.
o 1967 AERATED LAGOON
i
0.2
0.3
0.4
0.5
C.O. D. REMOVAL RATE - mg C.O.D. / mg MLVSS - DAY
FIG. 34. -NET SLUDGE GROWTH VS C.O.D. REMOVAL RATE
-------
0.2CH
o
I
CO
CO
>
o>
E
o.io-l
0.09-
0.08-
o, 0.07-
E
i 0.06-
u
< 0.05-
O 0.04-
Q.
CO
LJ
OC.
CO
O
UJ
CD
O
Q
z
LU
I
0.03-J
0.02-^
kT = 0.115 x i.14
T-20
o
0
0.115 y
LOG"' 0.057 = 1.14
10 15
TEMPERATURE- °C.
20
FIG. 35.-ENDOGENOUS RESPIRATION RATE VS TEMPERATURE
68
-------
at the temperature at which the aeration "basin is operated. The
relationship shows that the endogenous respiration rate increases
with higher temperature through the temperature range recorded during
the study. It also shows that the endogenous respiration rate of
the sludge was apparently independent of product processed.
The sludge growth constants which are given on the individual charts
in milligrams VSS/mg COD removed can be converted to sludge growth
constants in mgVSS/mg BOD removed by using the BOD over COD ratio
for the particular product being processed. A summarization is as
follows:
c c
Sludge Growth Constant Sludge Growth Constant
Product Being Processed mgVSS/mgCOD Removed mgVSS/mgBOD Removed
Pears O.U9 0.66
Peaches O.U6 0.69
Apples 0.57 0.76
The endogenous respiration rate (k) would not change between BOD
and COD consideration since it acts on the volatile suspended solids.
OXYGEN REQUIREMENTS
The oxygen requirements for an aerated system depend upon the amount
of organic matter removed from the waste stream and on the amount of
volatile suspended solids in the aeration system as was described by
equations (6) and (7).
02 = a'BOD or COD removed + Vk'MLVSS (6)
02/MLVSS = a'R+b'k (7)
The two constants a_ and .b can be determined by plotting the oxygen
uptake rate by the aerobic system versus the BOD or COD removal
rate. This plot yields a straight line curve through the data with
the slope of the line being a and the intercept on the oxygen uptake
rate axis being b_'.k. b_ would be determined by dividing ]o'k by the
endogenous respiration rate (k) at the particular temperature at
which the set of oxygen uptake rate data was gathered.
As is explained in Appendix D, the oxygen uptake rate studies made
with dissolved oxygen probe and meter were not necessarily at the
temperature at which the aeration system was being operated at the
time since the samples following their collection warmed up prior
to running the oxygen utilization curve and also warmed up during
the running of the test. Temperatures were taken during the tests,
however, and the temperature gained during the test calibrated so
that the temperature of reaction in the vessel used for the oxygen
uptake rate test was known. The majority of the tests run were at
approximately l6° C. , but some tests necessarily had to be run lower
or above that and some results from 12° C. and 20° C. were collected.
On some of the tests which lasted a long period of time, tangential
plots of the curve at more than one temperature were possible. These
69
-------
plots of individual tests are shown in Appendix D. The oxygen
uptake rate versus COD removal rate for the days on vhich the
uptake rate was run are plotted on Figures 36, 37, and 38. For
the plotting of the curve through the data points, it was assumed
that the slope of the curve would be constant on each of the plots
and that only the intercept would change with temperature. As it
appears from the data points plotted, this appears to be a valid
assumption. From these figures, it can be seen that
a = 0.S^mgOgrequired/mgCOD removed
By utilizing the approximate average BOD over COD ratio of the
raw wastes of 0.7^, it can be seen that a^ also has the value
a = 0.U6mgOp required/mgBOD removed
By taking the intercept of the plot from these three figures and
k_ as determined from Figure 3^ for the applicable temperature,
average
b = 1.2mg02 required/mgVSS
Using the constants already established and knowing the mixed liquor
volatile solids in the aeration system and the aeration basin temper-
ature, the oxygen transfer efficiency of the surface aerators used in
this treatment facility can be computed. Table VII shows computations
for aeration efficiency for different days through the two processing
seasons as calculated using these constants and formulas. These days
were not selected at random but were selected to show what the probable
maximum aerator oxygen transfer would be during the operation season.
It is shown from this table that the aerators can probably be relied
upon to produce an aeration efficiency of 2# of oxygen transfer/HP
hour expended for design. It would also be apparent, though, that
the larger units would have as good an efficiency as smaller units
if not, perhaps, slightly better. From the results available, not
very much in excess of 2# oxygen transfer/HP hour expended could be
relied upon. This means that the combined alpha and beta correction
factors for the aerators would be 0.57 for an aerator rated at 3.5
pounds of oxygen transfer per horsepower hour of standard conditions.
70
-------
CO
s
o>
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CM
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o>
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0.3J
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*
<
t
5
CD
>-
X
O
0.2-
O
'00.052 ma Qg£f\9 VSS-DAY
134 mg 02/mg C.O.D. REMOVED
0 O.I 0.2 0.3 0.4 0.5 0.6
C.O.D. REMOVAL RATE- mg C.O.D. / mg VS S -DAY (AT 12° C.)
FIG. 36.- OXYGEN UPTAKE RATE VS C.O.D. REMOVAL RATE
-------
Q
I
tn
OA-\
(M
o
i
ui
I-
<
o:
yj
a.
UJ
O
>
X
o
0.2-
0.1-
o
o
0.079 mg O^/mgVSS-DAY
o
I
O.I
r
0.2
i
0.3
.34 mg 02/mg C.O.D.
REMOVED
0.4 0.5 0.6 0.7
C.O.D. REMOVAL RATE-mg C.O.D/mg VSS - DAY (ATI6°C.)
FIG.37. - OXYGEN UPTAKE RATE VS C. 0. D. REMOVAL RATE
-------
U)
Q
I
CO
CO
o>
E
CM
O
o>
E
UJ
cc
UJ
OA-
0.3-
0.2-
O.H
HI
X
O
0.114 ma Oz /maVSS-DAY
0.34
mg 02/mg C.O.D.
REMOVED
O.I 0.2 0.3 0.4 0.5 0.6
C.O.D. REMOVAL RATE - mg C.O.D./mg VSS - DAY (AT20°C.)
FIG. 38. - OXYGEN UPTAKE RATE VS G.O.D. REMOVAL RATE
-------
TABLE VII
AERATOR OXYGEN TRANSFER EFFICIENCY
Aeration Basin #CL HP of #0p
Treatment DO Temp Transferred Aerators per HP
Date System mg/1 °C (Calculated) In Use Hour
10/1U/6? Activated i.U iU.5 2,080 60 l.UU
Sludge
10/1U/67 Aerated 1.3 lU.O 10,150 2UO 1.76
Lagoon
10/18/67 Activated O.U 12.1 2,020 60 l.UO
Sludge
10/18/67 Aerated O.U 12.0 10,7^0 2l*0 1.87
Lagoon
9/28/68 Activated 1.9 16.5 17,870 390 1.91
Sludge
10/5/68 Activated 1.8 lU.O l8,U60 390 1.97
Sludge
10/16/68 Activated 2.0 12.0 19,010 390 2.0U
Sludge
10/2U/68 A.S. w/ 2.9 12.8 19,700 U50 1.82
Sludge
Reaeration
10/26/68 A.S. w/ 2.U 12.5 20,H80 U50 1.90
Sludge
Reaeration
BOD AND COD CONTENT OF BIOLOGICAL SLUDGE
The BOD and COD equivalent of the "biological sludge in an aerated
system is important in the design and operation of the system since
a certain amount of the biological solids are going to escape into
the effluent. The amount of biological solids •which escape depends
on the design and operation of the facility and the efficiency of
the individual treatment units, including the aeration system and
the clarification system. As it was noted during both seasons of
operation, the effluent quality for both BOD and COD depended very
greatly upon the amount of biological sludge, measured as volatile
suspended solids, escaping in the effluent.
-------
Figure 39 shows the mgCOD/mgVSS versus the COD removal rate and the
mgBOD/mgVSS versus the BOD removal rate for the processing seasons
studied. As it can "be seen from Figure 39, the ratio of COD to VSS
does not change regardless of the removal rate of substrate "by the
biological solids in the system. However, the BOD of biological
solids changes with the BOD removal rate and increases as the removal
rate becomes greater. These relationships are as follows:
mgCOD/mgVSS =1.39
mgBOD/mgVSS = 0.3 + 0.28 x BOD removal rate
The reason for the BOD over VSS ratio being a function probably lies
in the fact that the solids accumulate unoxidized material for which
they utilize oxygen to synthesize new cells and that more of this
material accumulates when the organisms are working at a higher rate
and removing a higher amount of substrate per organism weight. The
chemical oxygen demand, however, remains constant regardless of the
loading rate since this unoxidized material converts to cellular
material still having the same chemical oxygen demand but which has a
lower biochemical oxygen demand.
In determining the efficiency of a system in the design these ratios
of COD and BOD to VSS must be taken into consideration in order to
assure the compliance with standards which may be imposed upon a
treatment system. The efficiency of the removal of a system will
depend largely upon the efficiency of the removal of these volatile
suspended solids or biological sludge from the effluent assuming
that aeration and nutrients and other factors are sufficient for
the proper treatment of the waste.
It can now be seen why the BOD removal efficiency improved while
the COD removal efficiency deteriorated in the aerated lagoon while
going from pear processing to apple processing waste. It is recalled
that an increase in detention time in the lagoon resulted, but also
that the treatment of apple processing waste occurred during much
colder weather. The lower temperatures slowed the rate of endogenous
respiration (Figure 37)s thereby allowing a higher MLVSS to be carried
in relation to the inflowing waste. The longer detention time allowed
a lower loading on these solids, thereby reducing their BOD exertion.
Since the BOD content of the solids was reduced more than enough to
offset the concentration increase due to temperature, a greater BOD
overall removal efficiency was realized while COD content of VSS
remained the same, so COD overall removal efficiency deteriorated.
NUTRIENT REQUIREMENTS
It was attempted to monitor the performance of the system in relation
to the nitrogen and phosphorus feeding rates and/or content of the
biological solids during this study. The 1967-1968 season data,
however, did not show very much correlation in any way, principally
because of the data collected. The data collected during that season
on nutrient content of the biological sludge was principally preserved
75
-------
CO
CO
o»
E
o
c>
o
Ol
E
1.5-
1.3-
1.2-
.cS>«So^
©
00 00
00 Q _
(9 0_
00 ©
x
1.39 mg CO.D./mg VSS
03
00
0
0
CO
CO
0.6-
0.5-
o>
E 0.4-
§ °-;
03
o> 0.2-
E
0 o,
0
0
© 0
mg B.O.D./mg VSS = 0.3 + 0.28^ B.O.D. REMOVAL RATE
i
O.I
0.2
0 O.I 0.2 0.3
B.O.D., C.O.D., REMOVAL RATE
0.4
0.6
0.8
0.5 0.6 0.7 0.8 0.9 1.0
mg B.O.D. /mg MLVSS-DAY, mg C.O.D./mg MLVSS - DAY
FIG. 39. - B.O.D.. GO.DL EOUIVAI FNT OF \/QQ
-------
samples, mostly canned. As it was stated elsewhere, these canned
samples gave unreliable data as to the form of the nitrogen and
phosphorus in the sample and it could not be determined which portion
was organic and which portion was not organic in the biological sludge
samples. The 1968 operating season data was much more reliable from
a sampling and analysis standpoint, but it was still very difficult
to determine any particular trends in treatment characteristics
related to the feed rate or content of these nutrient elements.
The results of the analysis on the biological sludge during the 1968
processing season are presented on Figure UO and plotted against the
COD removal rate at the time of the sampling. Preliminary inspection
of the data points as plotted would indicate that there would be some
trend where the nitrogen and phosphorus content in the volatile solids
measurement of the biological sludge vary as the COD removal rate.
Consideration of the data, however, precludes us from making any final
conclusions as to this possibility, since all of the data points pro-
gressed during the season timewise from right to left on this chart.
The points for high COD removal rates were collected during the initial
part of the season and for the Blower COD removal rates at the latter
part of the season and it is difficult to state positively that there
was sufficient nutrient in the inflowing waste to not deprive the
organisms partially during the initial part of the season. Actually,
there was no measurable soluble nitrogen in the effluent when the
lowest four N/VSS points were collected and no measurable ortho
phosphate when the two lowest P/VSS points were collected. Further
study would appear to be desirable on this particular aspect of
biological waste treatment and it is probable that any trends found
here would not be characteristic of fruit processing waste biological
treatment but would be characteristic of aerobic biological treatment
of other wastes as well. It can only be concluded that with sufficient
nutrients available as confirmed by residual nutrients being present
in the clarified waste stream from the biological treatment system,
that the approximate average nutrient contents of the biological
sludge for this study were as follows:
Organic P/mgVSS = 0.0l6mg
Organic N/mgVSS = O.OSTmg
These figures were not seen to go higher due to excess availability
of nutrients as more soluble nutrients (both N and P) were available
for the points at COD removal rates below 0.1. Since there is a constant
amount of biological sludge growth per weight of BOD or COD removed,
it is evident that there must be a certain amount of nitrogen and
phosphorus in relationship to this BOD or COD in order to sustain
proper growth of the organisms forming. However, at the same time,
there is nitrogen and phosphorus being released from the breakdown
of biological sludge by endogenous respiration. It has been stated
[9] that there is not a complete release of these nutrients by
endogenous respiration since there is a certain amount of the bid-
logical sludge which is relatively inert and does not break down
by endogenous respiration. A figure of 2Q% was suggested for this
amount [9l- Using the proportions of nitrogen and phosphorus in
the volatile suspended solids formed, COD and BOD removal and the
TT
-------
CO
CO
CO
>
o»
E
.1 I-
.10-
.09H
o»
O -08-
o>
6 .07-
.06-
to
C7>
.05-
,04-
X)3H
? .02^
o
? .01-
a&r~o~
600
o
o
0.087mq Pro N/maVSS
0.016 mg Org P/mgVSS
0.1 0.2
0.3 0.4 0.5 0.6
C. 0. D. REMOVAL RATE
0.7 0.8 0.9
FI6. 40.-NITROGEN AND PHOSPHORUS CONTENT OF BIOLOGICAL SLUDGE
-------
assumption that 2Q% of the nitrogen and phosphorus is non-returnable
to the system by endogenous respiration, the following formulas can
be derived for the nitrogen and phosphorus required for BOD and COD
removal.
N/COD Removed = 0.087cCOI)-0.80 x 0.087k/COD Removal Rate
N/BOD Removed = 0.087cBOE)-0.80 x 0.087k/BOD Removal Rate
P/COD Removed = 0.0l6c -0.80 x O.Ol6k/COD Removal Rate
COD
P/BOD Removed = 0.0l6c -0.80 x O.Ol6k/BOD Removal Rate
BOD
where
I m OQ \
k = 0.115 x 1.1V ~ ', T = Aeration Basin Temperature
Using these formulas, the curves on Figure Ul were plotted using
the sludge growth rate for pears and the endogenous respiration
rate at the various temperatures for which the curves were plotted.
As can be seen from the curves, there is a minimum amount of nitrogen
and phosphorus required even though the net sludge growth rate would
be theoretically zero at the point which these curves intercept the
minimum N/COD and minimum P/COD lines. This is because at a steady
state of operation, a zero net sludge growth rate cannot be practi-
cally attained and equations (3) and (5) would not be valid. Figure
hi. also shows that the point at which zero net sludge growth is
theoretically reached depends upon the temperature, due to the
dependence upon temperature of the endogenous respiration rate.
It can be seen from Figure hi that at removal rates in excess of
approximately 0.5 there is little saving in nutrient requirements
below what is required for conversion of the substrate directly
into biological solids with no endogenous respiration taken into
account. At below approximately 0.5mgCOD/mgMLVSS-day removal,
there is considerable saving, depending upon temperature, of
nutrients according to these theoretically derived curves.
Effects of Nutrient Deficiency
It is difficult to correlate the action of the treatment system diiring
these processing seasons to nutrient content or nutrient addition,
but it is possible that some of the observed portions of the processing
season when poor sludge settling and separation characteristics
occurred were due to deficiencies. The data collected was not
sufficiently frequent or accurate during the 1967-1968 processing
season to determine if this was the case. During the 1968 processing
season, it is possible that there was a slight deficiency in the
beginning of the season since during the early season the residual
ammonia nitrogen and phosphate in the clarified waste was at or
near zero. However, later in the season when the slowest settling
conditions occurred in the tests, the ammonia and/or nitrate nitrogen
79
-------
co
o
.05-
.04-
Q
O
d
on
E
o>
E
.03-
.02-^
-ON
MIN. N/C.QD. = .009
MIN. P/C.O.D. =.0016
T
2.0
T
T
0.5 1.0 1,5 2.0 2.5 3.0
C.O.D. REMOVAL RATE - mg C.QD./mg MLVSS-DAY
3.5
FIG. 41, — NITROGEN 8 PHOSPHORUS REQUIREMENTS FOR TREATMENT
-------
contents in the residual waste following clarification were well
above 1 mg/1 and the phosphate content was also well above 1 mg/1
which would indicate that the organisms had sufficient nutrient
available to take up all that they required.
During May of 1969» the cannery had a short run on apples which
had come out of storage and during this run the small aeration
"basin was operated as an aerated lagoon but with no nutrient
addition to try to evaluate the effect on treatment characteristics
when nutrient was totally deficient. After operating the system
for about two weeks without nutrients, a two day sampling program
was undertaken. The nutrients in the raw waste had a ratio of
nitrogen and phosphorus to COD of only N/COD = O.lU/100 and P/COD
= 0.06/100 and no measurable amount of either N or P remained in
the effluent. The organic sludge, or what was measured as organic
sludge developed in the system measured as VSS, contained only
O.OUmg N/mg VSS and 0.0052mg P/mg VSS.
The BOD and COD removal rate was effected severely and differed
greatly from what would have been expected from the data accumu-
lated earlier with respect to the residual soluble BOD and COD
available for uptake. The COD removal rate experienced was
approximately 0.76mg COD removed/mgMLVSS-day. From this removal
rate, a soluble COD concentration at the temperature of the lagoon
(19° C.) computed from the curve presented earlier would have
been 52mg/l. In the actual effluent the soluble COD over the
two days of operation averaged UlO mg/1. The BOD expected from
the removal rates experienced would have been only lU mg/1 but
the actual BOD in the effluent following filtration was 220 mg/1.
The net volatile suspended solids growth for the two days was 0.32
mgVSS/mgMLVSS. The calculated growth from the amount of COD removed
was 0.33mgVSS-/mgMLVSS for a very good correlation. The solids
accumulated in the basin were very dispersed and did not tend to
flocculate at all. No settlement of the solids occurred even
following setting overnight.
It can be concluded from the experiment that a serious lack of
nutrients effects flocculating and settling characteristics of
the suspended solids adversely and also adversely effects the
COD or BOD removal rate and makes the constants developed for
that expression invalid. Further study could be carried out as
to the extent of these effects and at what points nutrient
deficiency effects actually begin to be demonstrated and the
rate of progression of these effects with additional amounts
of deficiency. Until further data is accumulated along these
lines, it must be assumed that deficiency in nutrients below
the approximate lines developed for Figure Ul would adversely
effect the treatment efficiency and settling efficiency of an
aerobic system.
81
-------
BIOLOGICAL SOLIDS REMOVAL
The data gathered during study of fruit processing waste treatment
by aeration has indicated the "biological solids grown on the fruit
processing waste do not settle as rapidly as those from domestic
waste treatment systems. However, during the latter part of 1968,
the "biological solids settled out quite well to leave a very clear
effluent with a very low suspended solids in the effluent. A
relatively high sludge recirculation ratio of approximately 1:1 when
taken as to the influent waste flow or greater, was maintained and
this recirculation ratio seemed to quite adequately remove all of
the solids from the clarifier and a very low proportion passed over
the clarifier weirs into the effluent. It appears that the settle-
ability and separation characteristics of the "biological solids
improve with a lower BOD or COD removal rate in the system. It
also may be postulated that the settleability and separation
characteristics of the biological solids deteriorates with inade-
quate nutrient feed to the system.
The Sludge Volume Index (SVI) is a measure of sludge settleability
often used by sewage treatment plant operators in domestic sewage
treatment plants as a measure of the settleability and compaction
characteristics of activated sludge. The SVI is the settleable
solids in milliliters per liter times 1,000 divided by the suspended
solids in milligrams per liter and its units are milliliters per
gram as shown in equation (12)
SVI = Settleable Solids x 1000 ml/g (12)
Suspended Solids
The sludge volume index is normally determined on the settleable
solids after settling for one-half hour in a 1000 milliliter
graduated cylinder and divided by the suspended solids of the
sample. It can be used to determine the approximate concentration
of returned sludge which can be obtained which is computed as
follows [ 10 ]:
», • a. -i ^ j. j.. 1.2 x 1,000,000 „„/,
Maximum return sludge concentration = - = — * - mg/1
This is an equation used often in domestic sewage treatment plants
with standard scraper mechanism clarifiers where the sludge is
withdrawn at a center sludge well and swept into the sludge well
by scraper mechanism. By using a suction type clarifier probably
a factor greater than the 1.2 may be used. To make the equation
dimensionally true, no factor would be used at all, but the factor,
the 1.2 in the equation given, takes into account the compaction
and the thickening of the sludge due to the water depth in the
clarifier tank, the additional detention time in the clarifier
over and above what was available in the settling test, the hydraulic
overflow rate of the clarifier, and the action of the clarifier
mechanism in settling the sludge and compacting it. The sludge
settling tests were run for one hour during this study and 15 minutes
82
-------
prior to the reading at one hour the graduated cylinder in which
the test was being run was rotated by hand with care being taken
not to disturb the sludge blanket. The sludge settling curves for
the sludge are presented in Appendix C with the sludge being allowed
to settle greater than one hour to establish the curves.
During the 1968 operating season when clarification was practiced
with the suction sludge removal clarifier and with the clarifier
operating, the sludge being recycled was tested for concentration.
The factor in the returned sludge concentration equation which
would have been necessary during this entire period of time to
predict the sludge concentration being recirculated from the sludge
volume index as computed with one hour settling time was consistently
greater than 1.2. Nearly 50$ of the days in this period of time
the sludge concentration experienced would have required a factor
of 1.5 or greater to have been predicted. No attempt was made to
have maximized this factor but on the maximum day the factor would
have been 2.33- During this period, the overflow rate on the
clarifier was less than UOO gallons/square foot/day. It is felt
that the clarifier design including the vacuum sludge removal and
low overflow rate combined to aid in increasing the return sludge
concentration. A factor of 2.0 could probably be maintained on
this waste treatment system with this clarifier on a consistent
basis, provided that adequate dissolved oxygen and adequate nutrients
are present in the system for the biological growth. It is probable
that the characteristic settling curve which is quite slow for
sludge developed on this waste as shown on the curves in Appendix C
has a large part to do with this high compaction factor since the
activated sludge from a domestic waste treatment plant compacts
almost to its maximum amount within the first 1/2 hour with little
compaction taking place thereafter while the biological sludge
from the fruit processing waste in this system tended to continue
to compact and settle even up to 6 hours or more. The volatile
suspended solids averaged about 90 percent of the total suspended
solids in the biological sludge which may have accounted partially
for its slow settling rate. The sludge volume index during the
1968 season is plotted on Figure k2 versus the COD removal rate.
There is somewhat of a trend to this data in that the SVI slopes
upward from approximately 200 to UOO at COD removal rates from 0
to about 0.2 mg COD/mg VSS/day, then appears to sharply turn upward,
peak, and come back down and at approximately 0.6 and begin to
level off again at around 200. For all points obtained at removal
rates greater than 0.6, the MLVSS was less than 1000 mg/1. Also
considerable suspended solids (deflocculated sludge) remained in the
supernatant. Pipes [11] observed "deflocculated"sludge in similar
instances. It was in this same region of operation that inadequate
nutrients were available, which probably compounded the problem.
This curve is similar to curves that have been plotted by others
[ 3 ] and [12 ] for sludge volume index versus removal rate curves.
However, this curve starts much higher and peaks much higher than
the curve reported by Stewart [ 12'] where for domestic waste, the
curve begins at well under 100 and peaks at less than UOO then
returns to well under 100 again when the removal rate reaches
-------
1600-
1400-
' 1200-
x
UJ
o
z
- 1000-
ui
o
>
UJ
CO
o
CO
800-1
600-
400-
200-
oo
o
o
>
8P
o
o
o
o
o
o
O o
o
o
o
o
0 0.2 O.4 O.6 0.8 I.O 1.2
C.O. D. REMOVAL RATE - m g C.O. D./mg VSS - DAY
1.4
FIG. 42. — SLUDGE VOLUME INDEX VS GQD REMOVAL RATE-1968
8U
-------
approximately 3. Once again, the indication is that the biological
sludge grown in this system on fruit processing wasts has a much
slower settling rate than that for domestic waste and continues to
settle well beyond a period of which the settleable solids is read
in the sludge volume index computed. This makes the settleable
solids test and sludge volume index much different in a 'fruit
processing waste treatment system than in a domestic waste activated
sludge system, and the interpretation and use of the data must be
different also.
Sludge Wasting and Disposal
Sludge wasting is necessary from aerobic biological treatment systems
such as this in order to maintain a workable system. This sludge is
partially wasted over the clarifier weirs in the form of effluent
volatile suspended solids. The efficiency of this system largely
revolves around the amount of this sludge that is going out into the
effluent. In order to prevent excessive sludge from going out into
the effluent, sludge must be wasted from the system by other means.
The Snokist Growers waste treatment system had designed into it
sludge wasting with the use of a flotation thickener for the acti-
vated sludge. Difficulties in materials delivery and installation
and the short processing season did not allow the thickener to be
placed into operation during the 1968 season with the exception of
a short startup trial period. This startup trial indicated that
the particular system that was furnished had a deficiency in air
solution capacity and this has, hopefully, been rectified since
that time. It was found that the sludge was possible to thicken
although a maximum concentration of sludge cake obtained was only
about 2.5$ during the short period of operation. Further experience
will have to be gained before this can be established as a workable
system of sludge disposal. Of course, the workability of this
system will depend on the economics and the ability of the system
to eliminate as much water as possible from the sludge to be dis-
posed of. Thickened sludge disposal from Snokist Growers system
is anticipated to be used for fertilizer or land disposal. The
more concentrated the sludge can be made, the more economical will
be the disposal costs since the fertilizer value lies in the solids
only and not in the carriage water which must be included.
AERATION BASIN TEMPERATURE PREDICTION
In order to design a system for waste treatment using the enclosed
theory and the constants obtained, it will be necessary to estimate
the operating temperature of the aeration system. A rational approach
to estimating a temperature under operating conditions would take into
account the heat present in the incoming waste as well as the heat
being lost to the environment or gained from it. If the aeration
basin contents is assumed as the reference temperature then the heat
being added by the incoming waste flow will be:
85
-------
H. = h. Q(T - T )
i i i w
H. = Heat in the influent to the basin
Q = Flow - MOD
T. = Temperature of waste into basin - °C.
TW = Temperature of basin contents - °C.
h = Constant
i
The heat being lost to the atmosphere can be represented by:
H. = Heat lost to the atmosphere
a
6 2
A = Surface area of aeration basin - 10 ft.
T = Temperature of atmosphere - °C.
h = Constant
cL
Since the temperature of the effluent is the same as that of the
aeration basin contents, no relative heat is lost therein. If we
consider the heat loss to the ground and the heat contribution of
the aerators and biochemical reactions as negligible, then to
maintain an equilibrium influent heat and atmospheric heat loss
must balance. The amount of aeration in operation on the lagoon
would affect the constant h . This effect has been ignored here
since the data collected on this project contains so much scatter.
TJ —. TT
Hi ~ Ha
h,- Q (T* - T.-) = hn A(TW - T )
,L J_ W CL " Of
'Ofr \ *T "™ "^J * ~~ ^^ » -"IJ O_ * " »—•" J /
where
h = a = constant
Eckenfelder [13 ] evaluated this constant as approximately twelve.
Equation (13) can be plotted'to solve for the constant with data
collected. This was done with weekly average temperatures of the
influent waste stream and aeration basins studied. The weekly
average waste flow was used for the plot and a weekly average of
daily average temperature at the Yakima airport as collected by
the U. S. Weather Bureau D.U] [15]. The daily average temperature
as published is not the average of hourly readings but the average
of the high and low for the day. Figure ^3 contains this data
86
-------
with h_ evaluated drawing the line through the origin and the median
data point:
h = 2.5
As it can "be seen, the data is quite erratic. The influence of
the factors taken as negligible is unknown. Contributing to variance
are the air temperatures at the airport, six miles away and merely
the average of daily highs and lows. Residual heat in the basin at
atmospheric temperature changes, and temperatures taken only on
grab samples a few times a day would affect data as would the number
of aerators in operation.
To estimate the temperature of a facility under design, the flow
and its approximate temperature must be estimated and a proposed
aeration basin surface area chosen. History of atmospheric tempera-
tures for the locality can be found in published material.
Equation (13) can be solved for T the aeration basin temperature to
yield equation (lU).
T = QT. + h ATa (ll|)
w Q + h A
This equation can be used with h_ as found above or an assumed h_
to estimate the temperature in a proposed system.
87
-------
13
12
II
10
9
8
7
6
5
4
3
2
I
0-
o -
o o
I I
-2 -I
2.5
8
I I I
0123
A (Tw -Ta
I I I I I
45678
FIG. 43. — AERATION BASIN TEMPERATURE RELATIONSHIP
-------
RECOMMENDATIONS
Future Studies
It is recommended that several areas surrounding the treatment of
fruit processing waste would be desirable candidates for future
studies. Further definition of the mixing and dissolved oxygen
transfer efficiency and capabilities of the surface aerators would
be desirable, in addition to studies as to whether or not the
particular style of surface aerator affected these efficiencies.
It would be beneficial, to know the cause and effect relationships
which affect the settleability and compact ability of the biological
sludge developed on fruit processing waste. One special problem
which needs to be evaluated here is the effect of nutrient content
of the waste and of the biological sludge on the settling character-
istics , in addition to the nutrient content effect on efficiency of
treatment.
One final area of study which would be desirable is that of bio-
logical sludge removal and disposal. The removal aspect has been
provided for in the form of a flotation sludge thickener, but this
facility has not been tried or proven to date. The final disposal
beyond thickening is a source of concern since it is not known when
costs might be necessary for this disposal even if it can be
established that the nutrient value of the sludge is of some value
to an agricultural cropping operation.
Future Operation
The operation of the waste treatment facility at Snokist Growers
in future seasons is recommended to follow roughly that which was
followed during the 1968 season except that recirculation of sludge
would begin immediately. The activated sludge operation would
continue until the solids concentration reached a figure where
clarification or sludge return facilities approached the possibility of
failure to handle the load or aeration capability approached the
possibility of being exceeded. At this time, (MLVSS will approximate
2,500 mg/l) the sludge would begin recirculation through the small
basin where sludge reaeration would take place. Sludge wasting
would begin shortly after that and continue until the end of pear
processing at a rate necessary to maintain equilibrium (estimated
maximum rate of 9,000 pounds dry solids per day). After apple
processing begins the system will once again operate as an acti-
vated sludge system utilizing the large lagoon and clarifier with
only a portion of the aerators in operation. Dissolved oxygen
would be kept at 1 mg/l or above. It will be necessary to feed
nutrients to the system. The rate will depend on the waste load
and amount of sludge in the system and can be estimated from
relationships developed herein. It can be checked by the amount
of soluble ammonia and/or nitrate nitrogen and ortho phosphate
89
-------
soluble in the effluent. It would "be necessary to have gre.ater
than 1 mg/1 of either, as N or P, but some residual would be
necessary to assure a properly operating system. The feed rate
would be adjusted according to the residuals found.
The system can be expected to produce a few days of poor effluent
quality at the beginning of each season when only TO percent COD
removal efficiency is experienced and considerable solids will be
lost in the effluent. Improvement should take place so that
within two weeks 90 percent removal should be obtained. This will
be greatly improved upon if some biological solids exist in the
system prior to full scale production.
Future Designs
If this system were redesigned, the sludge reaeration capability
would be eliminated as too costly an item relative to its benefits.
Its inclusion here is directly attributed to the previous existence
of the small aerated lagoon. The aeration system, large PVC lined
aeration basin, final clarifier and sludge return facilities,
would be included in a redesigned facility. Also, a method of
waste sludge dewatering for disposal would be included. Further
evaluation of the flotation thickening needs to be carried out as
does investigation of alternative methods.
90
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ACKNOWLEDGEMENT
As with any study, the accomplishment of this project would not
have been possible without the aid and assistance of many persons.
First of all, the Board of Directors of Snokist Growers must be
acknowledged for their foresight and recognition of the need for
this type of project in sponsoring the application for grant funds
and backing the project from its inception to conclusion. Mr. Frank
Coleman and Mr. Jule Graff, general manager of Snokist Growers and
project director, respectively, were instrumental in the inception
of the project and keeping it functioning and on schedule throughout
its course. Mr. Bill Carter and Mr. Mel Christenson, who are in
charge of operations at the cannery are to be thanked for their
diligence and consideration during the months of study during which
at many times their operations were inconvenienced slightly and
their help sought in procuring aid in construction and modification
problems. Mr. Bill Boot who is in charge of product quality control
for Snokist Growers, assisted through his cooperation and coordination
of the quality control section's efforts in order to allow the waste
water research to continue unhindered.
Able advice on direction of the research and goals toward which to
aim the project were offered by many on the outside. Mr. Donald
Proctor of Washington State University, Mr. Walter Mercer of National
Canners Association, Mr. Jerry Harper of the Washington Water Pollution
Control Commission, and Mr. James Boydston and Mr. Kenneth Dostal of
the Pacific Northwest Laboratory of the Federal Water Pollution
Control Administration are all to be thanked for their assistance
and suggestions during the course of this project.
All of the results of testing from the project which are presented
in this report and in earlier data releases are a result of the
laboratory operation which was overseen and directed by Mr. Herbert
H. Hart of Snokist Growers. Mr. Hart also acted as chief operator
of the treatment facilities and the day-to-day operation of the
facilities was his responsibility. He was assisted in his laboratory
work by Nina Wright and Jeanne Holdridge during the 1968 processing
season and by Irma Rosseau and Harold Ayers during the 1967-1968
season. Assistance in sample collection was gained from Donald
Brown, Donald Steveson, Vernon Henderson, and Robert Calhoun during
the course of the study.
The principals and staff of Gray & Osborne were all helpful in their
suggestions and aid in working on various phases of the project. Mr.
John Poston was of considerable help in the design and construction
phases of the project facilities. Mr. Lyle Rayburn did considerable
work during the design and acted as the resident inspector during
construction and subsequent to the data collection, accumulated data
and drafted most of the figures present in the report. Elaine Hews
and Mary Buchanan have been very understanding and diligent in their
attempts to decipher the many complicated terms and expressions
presented in data reports, monthly reports, and the final report
for the project, and their placement into context.
91
-------
Many other unnamed persons provided services and assistance during
the course of the project who are too numerous to name here. Each
of them provided an essential service during the study of this
problem.
92
-------
BIBLIOGRAPHY
[1] O'Connor, D. J. & W. W. Eckenfelder, Jr., "Treatment of Organic
Wastes in Aerated Lagoons" JWPCF 32, U, 365, April, I960
[2] Eckenf elder, W. W., Jr. & D. J. O'Connor, Biological Waste
Treatment, Pergammon Press , 1961
[3] Stewart, Mervin J. & Harvey F. Ludwig, "Theory of the MAS
Waste-Water Treatment Process" Water & Sevage Works, Fe"b.
Mar. 1962
[U ] Pearson, Erman A., "Kinetics of Biological Treatment" paper
presented at Special Lecture Series on Advances in Water
Quality Improvement, University of Texas, April, 1966
[5 1 Standard Methods for the Examination of Water & Wastevater,
12th Edition, American Public Health Association, Inc-. , New
York, N. Y. 10019
[6] "Data Report for the First Year of Operation of WPRD 58-01-68",
Gray & Osborne, Consulting Engineers and Snokist Growers, Yakima,
Washington, October, 1968
iTl "Data Report for the Second Year of Operation of WPRD 58-01-68",
Gray & Osborne, Consulting Engineers and Snokist Growers, Yakima,
Washington, May, 1969
[8 ] Cannery Waste Treatment, Utilization & Disposal, prepared for
California Water Resources Control Board by Water Resources
Engineers, Inc., June, 1967
[9] Eckenfelder, W. W. , Jr., "Theory of Biological Treatment of
Trade Wastes" JWPCF, 39_, 2 (1967)
[10 ] Sewage Treatment Plant Design, Prepared by a joint committee
of the American Society of Civil Engineers and the Water
Pollution Control Federation, 1959 p.ll8
[id Pipes, Wesley 0., "Ecology of Sphaerotilis in Activated Sludge",
Third Annual Report, Department of Civil Engineering, Northwestern
University, Evanston, Illinois, December, 1967
[12] Stewart, Mervin J. , "Activated Sludge Process Variations, The
Complete Spectrum" Water & Sewage Works, Reference No. 196U
[13] Eckenfelder, W. W., Jr., "Design and Performance of Aerated
Lagoons for Pulp and Paper Waste Treatment" Proc. l6th Purdue
Ind. Waste Conf.
[lU ] Climatalogical Data, Washington, U. S. Department of Commerce,
Environmental Data Service Br., Environmental Science Services
Administration, 1967
P-5 ] Ibid. , 1968
93
-------
APPENDIX
-------
APPENDIX A
CONSTRUCTION & OPERATION
Appendix A contains tables summarizing the construction and operation
costs of the Snokist Growers treatment facility and a list of major
equipment used and manufacturers of the equipment items. Also in
this section on Figures A-l through A-T are pictures of the treatment
facilities.
Figure A-l shows the large aeration basin in the summer of 1968 during
construction activities when the center aerator (150 HP) was being
installed. The 0.020" PVC liner can be seen on the dike slopes although
the liner and its rock cover on the bottom are covered "by water. Figure
A-2 shows a more complete view of the treatment facility while Figures
A-3 and A-U show the aerators in operation on the small and large
lagoons, respectively. The clarifier in Figure A-5 accomplishes final
removal of suspended solids from the effluent. The mechanism in the
clarifier contains vacuum sludge removal manifolds which rapidly pick
up the settled solids. The solids are then returned to the aeration
basin via the sludge return pumps shows in Figure A-6. Sample testing
for the study and for control of the waste treatment system is done in
the laboratory pictured in Figure A-T.
95
-------
TABLE A-l
COSTS OF CONSTRUCTION OF TREATMENT FACILITIES
I. CONSTRUCTION PRIOR TO BEGINNING OF R & D PROJECT
A. Original Construction - 196U
1. Small Lagoon Construction -
236' x 136' x 8' Deep
2. Asphalt Lagoon Lining - Blown in
Place
3. Two 30 HP Surface Aerators
U. Aerator Supports , Walkways and
Installation
5- Aerator Electrical
6. Lagoon Piping
7. Outfall to Yakima River -
1685' of 18" and 15" Concrete Pipe
8. Fencing - 1170' Chain Link
9. Miscellaneous
10. Engineering
B. Rectangular Settling Tank - 1966
$13,801.21
U,606.11
16,681.60
7,720.26
3,5^1.68
3.3.81.UU
13,393.27
2,153.32
2,295-66
7,357.77
1. Steel Tank - Complete with accessories-
Installed
TOTAL
II. CONSTRUCTION FOR AND DURING R & D PROJECT
A. Aerated Lagoon - 1967
1. Lagoon Construction -
277' x 280' x 12.5' Deep $15,200.93
2. PVC Lagoon Liner - Installed
with Rock Cover* 3^,229-6U
3. Lagoon Influent and Effluent
Structures and Aerator Footing 12,8^5.60
k. Four 60 HP Surface Aerators Ul,760.71
5. Aerator Installation 3,93^.2U
6. Aerator Walkways 11,027.08
7. Aerator Electrical 3,633-91
8. Lagoon Piping 10,3^2.10
9. Fence - 15^0' Chain Link 5,159-00
10. Miscellaneous 2.530.06
$7^,932.32
2U,830.26
$99,762.58
$lUo,66U.i6
* Including Snokist's Costs Incurred for 1968 Repair and Reconstruction.
96
-------
TABLE A-l - Continued
B. Clarification and Sludge Return, Added
Aeration, Thickener - 1968
1. Sludge Return Pipe and Aerator/
Walkway Footings
2. Variable Speed Sludge Return
Pumps - Two - 1T50 GPM
3. 150 HP Surface Aerator
U. Suction Clarifier Mechanism -
90' Diameter
5. Flotation Sludge Thickener
Equipment
6. Pump Building - 2U' x 30'
7. Clarifier Structure - 90' Diameter
x 9' SWD and Mechanism Installation
8. Aerator Installation and
Aerator Walkway
9. Thickener Appurtenances and
Installation
10. Piping and Flow Control Structures
11. Influent and Sludge Flow Meters
12. Thickened Sludge Pump and Piping
13. Electrical and Controls
C.
Laboratory
1. Building - 36'
2.
x 22' with Heating,
Plumbing, Electrical
Cabinets, Counters and Flume Hood
D. Engineering
1. Preliminary Planning
2. Plans and Specifications
3. Construction Services
E. Laboratory Equipment
1. Drying Oven
2. Muffle Furnace
3. Analytical Balance
U. Dissolved Oxygen Meter
5. BOD Incubator
6. Kjeldahl
T. Distillation Apparatus
8. pH Meter
9. Colorimeter-Spectrophotometer
10. Miscellaneous Equipment and Glassware
TOTAL - 1967-1968 CONSTRUCTION
TOTAL COST OF TREATMENT FACILITY
$ 5,258.50
6,888.00
23,950.00
21,U60.00
28,590.00
6,200.00
58,200.00
5,020.00
15,800.00
22 ,069. HO
2,800.00
7,850.00
lU,800.00 $218,885.90
$19,175-00
9,667.0^
$ 6,95^-81
25,313.5U
13,139.36
$
28,8U2.0U
U5,U07.71
291.55
801*. 65
1*70.25
5^8.62
1,722.16
571*. 75
67U.03
1*12.78
3,856.21*
$UU3S395.29
$5^3,157.87
97
-------
TABLE A-II
MANUFACTURERS OR SUPPLIERS OF MAJOR EQUIPMENT*
EXISTING FACILITIES
1. Vibrating Screens - 2 each
2. Surface Aerators - 2-30 HP
3. Lift Pumps and Sludge Return Pump
196T CONSTRUCTION
1. Aeration Basin PVC Lining .020 In.
2. Surface Aerators - h-60 HP
3. Flow Meter and Recorder
1968 CONSTRUCTION
1. Surface Aerator - 1-150 HP
2. Clarifier Mechanism - 90 feet
Diameter Suction Type
3. Sludge Return Pumps - 2-1750 GPM
U. Sludge Pump Variable Speed Drives
5. Sludge Flow Meters - Propeller Type
6. Flotation Sludge Thickener
7. Thickened Sludge Pump
8. Laboratory Equipment
9. Dissolved Oxygen Monitor
Link Belt Company
Infilco
Wemco
Staff Industries
Eimco Corporation
Leupold & Stevens
Eimco Corporation
Eimco Corporation
Chicago Pump Company
Furnas
Rockwell
Eimco Corporation
Moyno Pump Division
RoTsbins & Meyers
Van Waters & Rogers
Weston & Stack
LABORATORY EQUIPMENT*
1. Analytical Balance
2. Dissolved Oxygen Meter
3. B. 0. D. Incubator
U. Kjeldahl Unit
5. Distillation Apparatus
6. pH Meter
7. Colorimeter Spectrophotometer
Mettier
Yellow Springs
Instrument
Fisher
Lab con co
Corning
Fisher
Bausch & Lomb
*Note: Trade names are for information only and do not
constitute an endorsement of the equipment "by
the FWPCA nor the author.
98
-------
TABLE A-III
COST OF OPERATION OF TREATMENT FACILITY
1967-1968 OPERATING SEASON
1. Electrical Pover $ 6,370
2. Nutrient Chemicals 10,530
3. Supervision & Operation 10,868
U. Maintenance Labor 1,332
5. Maintenance Materials 630
6. Laboratory Technicians 55250
7. Laboratory Chemicals and Equipment 2,750 $37»730
1968 OPERATING SEASON
1. Electrical Power $ 9,OUO
2. Nutrient Chemicals 10,7^2
3. Supervision and Operation 11,730
U. Maintenance Labor 1,262
5. Maintenance Materials 630
6. Laboratory Technicians U,700
7- Laboratory Chemicals and Equipment 2,280 $UO,38U
99
-------
I
H
o
o
p,G A_L LARGE AERATION BASIN SHOWING THREE OF THE FOUR
60H.P AERATORS, 150 H.P. AERATOR, RV.C. LINING ON DIKE, AND INFLUENT STRUCTURE.
-------
'.-•^•c
FIG. A-2.—WASTE TREATMENT SYSTEM FROM SCREENING
STATION PLATFORM.
FIG. A-3. — 30 H.P AERATORS IN SMALL AERATION BASIN.
101
-------
FIG. A-4. — LARGE AERATION BASIN - AERATORS OPERATING
o
ro
FIG. A-5. — FINAL CLARIFIER; SMALL LAGOON, SCREENING STATION,
CANNERY BUILDINGS AND SLUDGE PUMP BUILDING IN BACKGROUND.
-------
H
O
bo
FIG. A-6. —
SLUDGE RECIRCULATION PUMPS
SLUDGE PUMP BUILDING.
AND PIPING IN
-------
FIG. A-7. — WASTE WATER
LABORATORY
INTERIOR
-------
APPENDIX B
SAMPLING AND TESTING
Sampling during each of the two processing seasons over vhich the
project extended vas done by hand. Composite samples vere taken
during the processing day on the screened influent to the treatment
systems, on the effluent from the aeration basin, and on the effluent
from the clarifier and on the return sludge from the clarifier when
the clarifier was in operation. Grab samples were taken periodically
of the aeration basin contents for settling tests and suspended and
volatile suspended solids tests.
The flow from the cannery was metered over a two foot rectangular
weir and integrated with the use of a water level recorder which
recorded the water height falling over the weir crest. The flow
when split between the two aeration basins was done by a divider
plate being positioned in front of the weir which split the flow
between the influents to the two aeration systems. Changes in
this divider plate position were recorded in order to get an
accurate record of the flow disposition. During the second year
of operation when a totalizer was added to the water level recorder,
the totalizer was read daily in addition to the flow chart being
integrated manually.
Sample Compositing, Storage and Preservation
The hand taken samples were composited on approximately an equal
basis throughout the operating day since on any particular operating
day the flow did not vary greatly from the cannery and was considered
to be even enough to allow this method of compositing. Samples were
not taken during the washup period which usually occurred between
midnight and seven a.m. in the morning. It vas determined, through
successive trial calculations that the total daily load of BOD and
COD in the waste from the cannery could be determined by using the
concentrations found from testing of the composite samples collected
during the processing day and over a flow total which included the
flow during processing itself and for an additional two hours per
day. This two hours included time between shifts and down time
during shifts. As an example, if two shifts were run per day
beginning at 7 a.m. and extending until midnight during which
sixteen hours of actual processing occurred, the flow to be used
for computation of waste load would extend from 7 a.m. to 1 a.m.
the following day, or 18 hours as opposed to the 16 hours of actual
processing. Figure B-l shows typical daily flow records.
During the 1967-1968 processing season, a temporary laboratory was
necessary in order to accomplish the testing program since the new
laboratory was not yet constructed. Since the facilities were
limited in this temporary laboratory, it was attempted to preserve
samples for later testing by placing the samples in No. 2-1/2 or
No. 303 cans and running them through the same process as produce
cans where lids were placed on them and the cans were sterilized.
105
-------
It was anticipated that such tests as BOB, COD, nitrogen, phosphorus
and total volatile solids could be performed on these canned samples.
The test for total volatile solids and nutrients was apparently valid
from these samples although it appeared that the BOD and COD values
could have changed somewhat due to the preservation, especially in
samples containing suspended solids. In addition, it was only the
total nitrogen and phosphorus tests which were valid since the
organic nitrogen and organic phosphorus was partially "broken down
into ammonia nitrogen and phosphates due to the canning process
which involved a high heat for sterilization. This caused diffi-
culty in allocating nitrogen and phosphorus values to the "biological
solids in the sample. As a result of this experience, it is recommended
that in future studies this method of sample preservation not "be
utilized with the exception of perhaps on the raw waste where nutrient
values and total solids might be concerned. The BOD values obtained
from the preserved samples along with data from fresh samples were
used in plotting Figures U and T« It was not necessary to use COD
data from the preserved samples since adequate analyses were run on
fresh samples.
During the second season of operation, due to some difficulties
with apparatus for a short time, some samples were frozen for
preservation for later testing. Only three sets of samples were
handled in this manner and on these sets of samples only nutrient
values were obtained from the testing with the exception of one
sample set where BOD's were necessary. An additional set of samples
upon which analysis had been done on fresh samples were also frozen
to act as a pilot. The BOD as determined from the frozen sample
was not the same as the BOD's found on the original sample and *
consequently the frozen sample BOD's were not considered usable.
This is especially true of the biological effluent from the treat-
ment system where the BOD contributed to by the volatile suspended
solids was increased. There did not appear to be any alteration
of nutrient values or of shift in the forms of nitrogen or phosphorus
due to the preservation by freezing.
PJL
The pH was measured electrometically, standardized to 25° C.
utilizing B. glass electrode on fresh grab samples from the treat-
ment systems [B-l ]. The pH as recorded for the influent was an
average of 2 or 3 grab samples during the processing day.
Settie able Solids
Settleable solids were measured using 1,000 milliliter graduated
cylinders or, in the case of clarified effluents, one liter settling
cones. Readings for settleable solids were taken in one hour and to
produce the settling curves at one hour intervals thereafter.
106
-------
Suspended and Volatile Suspended Solids
Suspended and volatile suspended solids analyses were run "by filtering
the sample through a grade GFC glass-fiber filter which was designed
to retain particles in a semi-colloidal range. This glass filter
paper was pre-washed in a diluted acid solution and in distilled
water, fired in the muffle furnace and tared prior to filtering the
sample with the use of a vacuum filtration apparatus. The filter
was then dried and weighed for a total suspended solids determination.
The filter and residue following firing in a muffle furnace at 550° C.
was cooled and weighed again to determine the fixed solids and the
volatile solids by difference. This method is as described by
D. Jenkins [B-2].
Total Solids and Total Volatile Solids
Total solids were determined "by drying a sample in a tared drying
dish and reweighing. The total volatile solids were determined "by
the difference "between the dry solids reading and the weight following
ignition at 600° C. in a muffle furnace [B-l].
Chemical Oxygen Demand (COD)
The COD determination was done by the method described in Standard
Methods [B-l] using potassium dichromate as an oxidizing agent. One
modification was made in the procedure as described by Standard
Methods, that being that 10.0 ml of sample or less was used and
20.0 ml of standard potassium dichromate solution was used to reduce
the amount of dilution of the samples.
Biochemical Oxygen Demand (BOD)
The BOP determinations were performed according to Standard Methods
[B-l ]. The waste treatment system effluent was used for seed for
the raw waste and when it was available,on preserved samples.
Seeding was done on other preserved samples by using the effluent
from the Yakima City Sewage Treatment Plant for seed material.
Pissolved Oxygen
The dissolved oxygen was measured with the use of a dissolved oxygen
probe and analyzer calibrated in air prior to use. Temperatures in
the lagoon were also taken with this analyzer and a thermistor probe.
(Appendix P contains a further discussion of this meter).
Ammonia Nitrogen
Ammonia nitrogen was determined by distillation and titration of
the distillant with H^SO^ as outlined in the 12th Edition of
Standard Methods [B-l].
107
-------
Organic Nitrogen
The .organic nitrogen determination was made according to Standard
Methods [B-l ] using the Kjeldahl method. The samples which were
earlier distilled for ammonia determination were digested in acid
solution and then the ammonia nitrogen was distilled off and
determination was made for ammonia nitrogen on the distillate.
Nitrate Nitrogen
Nitrate nitrogen was determined Spectrophotometrically using
Brucine as outlined by Krawczyk [B-3 ] and Jenkins and Medsker
Orthophosphate
Orthophosphate was determined in accordance with Standard Methods
12th edition [B-l]. The Stannous chloride method was used util-
izing extraction into Benzene-isobutanol.
Total Phosphate
Total phosphate was determined according to Standard Methods [B-l ]
which utilized "boiling the sample in acid solution and subsequent
analysis for Orthophosphate.
Total Phosphorus
Total phosphorus which includes ortho and total phosphate in
addition to organically "bound phosphorus was determined utilizing
a method used at the Sanitary Engineering Research Laboratory of
the University of California in Berkeley [B-5]« This determination
consists of alkaline ashing of the sample at 800° C. followed "by
determination of the phosphorus utilizing strong acid molibdate
reagent, heating on a steam table to attain reaction. Color
development is done using Aminonaphtholsulfonic acid or Stannous
chloride reducing agent . Color reading is then done on a
Spectrophotometer and comparison made with a standardization
curve .
Oxygen Uptake Rate
The method for determining oxygen uptake rate is presented in
Appendix D.
Supernatant and Settled Sludge Samples
Testing was done on a portion of the aeration basin samples and
effluent samples on the basis of the supernatant and settled
sludge from the samples. This supernatant and settled sludge
was obtained by taking a composite sample or grab sample from
the station and allowing to set overnight in a refrigerator.
108
-------
Supernatant is drawn off the top of the sample the following day
and the sludge from the "bottom was tested as a settled sludge
sample. The intermediate portion where the sludge and supernatant
were partially mixed was discarded. Testing of these samples was
done in order to determine the nutrient content of the biological
solids and the remaining dissolved constituents in the waste.
REFERENCES
[B-l ] Standard Methods for the Examination of Water and Wastewater,
12th Edition, American Public Health Association, Inc. , New
York, N.Y. 10019
[B-2 ] Jenkins, D. , "An Improved Volatile Solids Determination,"
Water and Waste Treatment Journal (London) August/September,
1962
[B-^3 ] KrawczykjD. F. , "Phosphorus and Nitrogen Analysis for
Wastewater Treatment Plant Control", Pacific Northwest
Water Laboratory, Corvallis, Oregon February 7» 1968
[B-lt ] Jenkins, D. and L. L. Medsker, "Brucine Method for
Determination of Nitrate in Ocean, Estuarine and Fresh
Water", Analytical Chemistry, 36_, 610 (196U)
[B-5 ] Menar, A. B., Private Communication, January 9-. 1968
109
-------
3.0-1
2.0-
I .0-
PEAR PROCESSING
9 12 PM 369 12AM 3
OCTOBER 10, 1968 -TOTAL FLOW = 1.96 M.6.D.
6
3.O-
2.0-
*
O
O
3S
0-
-jJ ^^" ^~ ^^L^-,
PEACH PROCESSING
i i r i i i i i
| 9 12PM 369 12AM 3 6
_ SEPTEMBER 10, 1968 - TOTAL FLOW* 2.33 M.6.0.
3:
o
_j
3.0^
2.0-
1.0-
APPLE PROCESSING
i
3
i
6
9 12PM 369 I2A« 3
NOVEMBER 13, 1968 -TOTAL FLOW = 0.49 M.6.D.
TIME OF DAY
i
6
FIG. B-l — TYPICAL DAILY PROCESSING FLOW
no
-------
APPENDIX C
This appendix contains the sludge settling curves as plotted from
data taken during the two operating seasons of this project. These
settling curves are the result of hourly readings of the top of the
sludge layer in 1,000 milliliter graduated cylinders following the
placement of the aeration "basin contents into the cylinder. Fifteen
minutes prior to each reading, the cylinder was rotated back and
forth approximately 120 degrees "by hand with care "being taken not
to disturb the contents of the cylinder enough to resuspend portions
of the solids which were or had been settled out. The reason for
this action was to dislodge any particles which may have been clinging
to the cylinder walls and to give a small amount of motion to the
liquid in an effort to get the floe particles to compact more fully.
The dates when the samples were taken and the curves observed are
given on each individual plot. During the 1967-1968 season when
two treatment systems were in operation, the data points are identi-
fied on the figures. Figures C-l through C-8 contain curves from
data collected during the 1967-1968 processing season. Figures C-9
through C-lU represent data accumulated during the 1968 processing
season.
Ill
-------
1000-
SS.= 1490
ui 7
gS
3§
CO <
_l
o
UJ O
£UJ
< I-
> <
i- tr
o uj
< <
500-
S. S.= 883
9- 20-67
UJ
\ \ i r
2468
i.S. = !640
02468
1000-
S.S.= I940
500-
9-22-67
\ i i
246
1000-
500-
S.S.= 470
S.S.= I860
9-29-67
S.S.= 780
r
8
8
SETTLING TIME - HOURS
FIG. C-l. — SLUDGE SETTLING CURVES
.112
-------
1000
S.S.- 830
• o
1000-
E
I
QC.
Ul
500-
Ul
CD
O
S.S.= 1430
10-20-67
02468
1000-
500-
S.S.=
1000-
500-
10- 18-67
i i i f
2468
S.S.= 875
10-23-67
I T \ \
2468
CO
u.
o
X
CD
Ul
X
1000-
500-
£S.= 830
S.S.M430
10- 25-67
I
2
I
4
i
6
8
1000-
500-
S.S.= 540
S.S.= I205
10 - 27-67
SETTLING
0 2
TIME- HOURS
\
4
8
FIG. C-2.— SLUDGE SETTLING CURVES
113
-------
1000-
Sz
1 {*)
to <
_j 500-
0
UJ
< £
o ui -.
< < u
fc^O^O^O^O^JL0 IOOOH
^~^*qc^S
S.S.- 1480
500-
II - 1-67
,
^>-0-0-^>-o_o
S.S.= 715
11-3-67
i i i i
00 02468 02468
IOOO-<
E
i
500-
oc
UJ
$
_j
^-o— 0—0-0— o-o— o IOOO-<
S.S.= 730
500-
II - 8 - 6 7
1 1 1 1 °
-O-O-O-O-^x^
S.S. = 650
11-10 -67
i i i i
02468 02468
Ul
o
-3
_i 1000-
to
u.
0
x 500-
o
Ul
X
0-
•
1
^-o-^-o-p-^^^^ 1000^
S.S. = 485
SOO-
N-IS - 67
— — .-.. ,i n
1 1 i i u
^-°— o-o-o-^
S.S. = 475
1 1 - 17-67
1 1 1 1
02468 02468
SETTLING
FIG. C-3. —. SLU DGE
TIME - HOURS
SETTLING CURVES
-------
1000-
500-
S.S.= 5I5
- 29-67
i I I r^
2468
1000-
500-
S. S.= 390
12- 1-67
I
2
468
1000-^
i
o:
500-
S.S.= 560
12-6- 67
i 1
2 4
6 8
CO
1000-
500-\
UJ
S.S.= 525
12- 13-67
0 2
I
4
I
6
I
8
1000-
500-
S.S.= 560
12-8-67
02468
1000-
500-
S.S.- 500
2-15- 67
I
4
0 2
SETTLING TIME - HOURS
I
6
8
PI Q c-4.—S LU DG E SETTLING CURVES
115
-------
1000-
500-
S.S.= 490
12 - 20-67
I I i I
2468
1000-
500-
S.S.= 460
1-5-68
r i \ \
02468
Ml 1 v>^ V '
_J
m 500-
o
0
i
CO
o
•**— *s^,^ i^^^^ •
S.S.= 5O5^>o
500-
1 - 10 - 68
r»
^<,
S.S. = 520 ^
1-12-68
n i i i i i i i i
02468 02468
u_
0
^^ l^/^/V '
X
o
Ul
I
500-
0-
C
L_O__O__C.^ IOOO-<
S.S.= 530
500-
1-17-68
. -JJ«ift— ». ^- ^\
1 i i i °
) 2 4 6 8 <
-o-°-o-o-o
S.S. = 580
1 - 19-68
I ii I
D 2 4 6 8
SETTLING TIME- HOURS
FIG. C-5. — SLU D6E SETTLING CURVES
116
-------
1 ^ W
500-
0-
(
S.S. = 51 0
500-
1-24-68
r\
i l i i °
) 2 4 6 8 C
S.S. = 500
1-26-68
i i i i
) 2 4 6 8
E
.
(r IOOO-(
UJ
>
<
_j
u 500-
o
0
3
I
mm*
to
0-
u. (
H-o-^x IOOO-<
^^^V
S.S. = 490 ^~°
500-
1-31-68
. ,,,.,ii.. O
1 1 l I L
) 2 4 6 8 <
^^^-o^
S.S. = 490
2-2-68
l I 1 l
D 2 4 6 8
o
,_ 1000^
X
e>
iij
X
500-
0-
C
KIOOO^
S.S. = 480
500-
2-7-68
• 0
1 1 l 1
) 2 4 6 8 C
k
\
\
b
\ S.S. = 400
A.
V^
2-9 -68
l i l i
) 2 4 6 8
SETTLING TIME- HOURS
FIG. C-6. — SLU DG E SETTLING CURVES
117
-------
1000-
UJ z
g?
o o
_» e>
to <
_i
o
UJ Q
I- UJ
< I-
> <
I- *
o u
< <
• o
500-
S.S. = 435
2-16-68
02468
1000-
500-
2-21 - 68
I
2
T
4
~
6
~
8
E
i
or
UJ
UJ
o
Q
3
_J
CO
1000-
500-
S.S.= 400
2-23-68
T
2
I
4
I
6
I
8
1000
500-
8
o
UJ
1000
500-
1000
500-
SETTLING TIME - HOURS
FIG. C-7. — SLUDGE SETTLING CURVES
118
-------
1000-
1000
S.S. = 740
S.S. = 775
500-
500-
5-1-68
5-3-68
~
4
~
8
I
2
I
4
8
o:
UJ
UJ
o
o
CO
u.
o
U
I
1000-
500-
S.S. = 865
1000
500-
5-7-68
i I r
246
8
1000^
500-
1000
500-
S.S. = 635
5-10-68
\
2
I
4
8
SETTLING TIME -
FIG. C-8. — SLUDGE SETTLING CURVES
119
-------
1000
500-
1000
500-
2 4
8
oc
UJ
UJ
o
z>
_1
(O
1000
500-
1000
500-
8
1000
o
UJ
i
500-
1000
500-
8
SETTLING TIME -
FIG. C-9.— S LU D6E SETTLING CURVES
120
-------
1000
500-
1000 H
500-
s.s. = sso
9- 13-68
I T I I
2468
a:
UJ
LU
o
o
CO
1000
500-
9-18-68
2 4 6 8
lOOO
500-
S.S.= 1120
9-20-68
I I I r
02468
H 1000
500-
S.S.-I550
9-25-68
I I I T
02468
1000-
500-
S.S. - 1790
9-27-68
02468
SETTLING TIME - HOURS
FIG.C-IO. — SLUDGE SETTLING CURVES
121
-------
1000-
500-
S.S.-I920
9- 30- 68
ill r
2468
IOOO-<
500-
S.S. = 2240
10- 2-68
i
2
I
6
8
- 1000-
o:
UJ
Ul
Q
CO
U.
o
I-
X
UJ
500-
S.S.= 2610
10-4-68
I I I
2 4 6
1000-
500-
S.S. 2970
10- 9^ 68
0 2
I
6
I
8
I
8
1000-
500^
S.S.= 2750
10- 7-68
02468
1000-
500-
S.S. = 3260
10-11-68
I
2
468 024
SETTLING TIME - HOU RS
X
6
FIG. C-ll. —SLUDGE SETTLING CURVES
i
8
122
-------
1000-
500-
S. S.= 3380
10-14-68
I
2
I
4
I
6
8
1000-
500-
S.S.= 3540
10- 16-68
Till
2468
E
I
UJ
<
_!
UJ
0
_J
CO
1000-
500-
S.S. = 27IO
10-18-68
I
4
6
i
8
100
500-
1000
I-
x
o
UJ
I
500-
1000
500-
8 0
SETTLING TIME - HOURS
FIG. C-12. — SLUDGE SETTLING CURVES
123
-------
1000
500-
1000
500-
8
8
oc
UJ
uj
o
Q
Z3
_l
CO
u.
O
I-
X
O
UJ
1000
500-
1000
500-
S.S.= 2790
8
1000
500-
S.S. = 2750
1-6-68
i
2
I
4
\
6
1000-
500-
S.S. - 2400
11-13-68
8 02
SETTLING TIME -HOURS
\
4
6
I
8
8
FIG. C-13. — SLUDGE
SETTLING CURVES
12U
-------
1000
500-
1000
8
500-
E
I
OC
UJ
1000
U)
&
o
3
_l
(f)
u.
o
I-
I
—
UJ
I
500-
1000
1000
500-
500-
1000
500-
8 0
SETTLIN G TIME - HOURS
FIG. C-14.- SLU DG E
SETTL ING
CURVES
125
-------
APPENDIX D
OXYGEN UPTAKE STUDIES
Studies of the oxygen uptake rate of the biological sludge mass
were run during "both seasons of operation. The testing was run
on grab samples taken from the aeration mixed liquor with the
use of dissolved oxygen probe and meter. This dissolved oxygen
probe and meter made by YSI did not have proper temperature
compensation so correction curves were plotted for the meter
itself. The standardization point of the meter was recorded
at the time of making the uptake rate studies so the correction
curves could be used to correct the individual readings during
each test. Figure D-l shows the standardization curve as rec-
ommended by the meter manufacturer for standardizing the meter
in air according to the water temperature to be tested. , This
curve is compensated to the altitude at which the tests were run
in Yakima. Figure D-2 shows the correction curves as plotted by
the study personnel from water of known dissolved oxygen content.
The meter readings were corrected to DO in mg/1 by finding the
standardization reading in air on the lower axis of Figure D-2
going up to the line representing the temperature of the sample
at the time of the-reading, thence over to the YSI reading over
DO in mg/1 and dividing the YSI reading by that figure, found
on the vertical axis of the correction curves. All of the DO
uptake curves were corrected with the use of this chart.
The actual testing was run by taking the sample and placing it
in a 2,000 milliliter Erlenmeyer flask, lowering the probe into
the flask, sealing the top of the flask with a rubber stopper
and placing the flask on a magnetic stirrer for agitation. Each
of these samples was aerated vigorously for 30 seconds to one
minute prior to placing in the flask in order to assure an ample
supply of dissolved oxygen for the organisms in order to estab-
lish a curve. It was found that because of the heat emitted by
the magnetic stirrer that the samples gained in temperature at
approximately a constant rate during the uptake test. The average
rate of temperature gain was 6.3° C. per hour and the rate slacked
off when the temperature got above approximately 18° C. Normally
the temperature was read at the beginning and at the end of the
test which made assignment of temperatures to the individual
readings relatively easy and which made the correction of the
readings relatively easy with the use of Figure D-2. The tempera-
ture at which the DO probe and meter were standardized prior to
the test was recorded in each instance. Figures D-3 through D-5
contained the DO uptake rate curves run during the 1967-1968
processing season. There were no curves run after October 31»t
1967 since the dissolved oxygen probe became unworkable at that
time and had to be repaired prior to usability. Figures D-6
through D-8 contain the oxygen uptake rate curves ran during
the 1968 season.
126
-------
As it can be seen, with the gain in temperature the oxygen uptake
rate increased so it was attempted to plot the slope tangent to
the point at which curve passed through a particular temperature.
As it can be seen, this caused more than one temperature and
separate DO uptake rates to be recorded. The rate on the figures
is the slope of the tangent line divided by the volatile suspended
solids.
127
-------
-------
1.8-
1.6-
1.4-
o>
E
i
6
Q
1.2-
1.0-
z
Q
<
UJ
QL
_ 0.8-
co
0.6-
0.4-
READINGS/ D.O. VS
STANDARDIZATION READINGS
IN AIR AT VARIOUS WATER
TEMPERATURES
25° C.
I
9.0
YSI
10.0
STANDARDIZATION
I
1.0
IN
20° C.
5°C.
I 0°C.
5° C.
12.0
AIR TO
13.0
- m g / I
FIG. D-2. - YSI CORRECTION CURVES
129
-------
H
U)
O
o>
E
LU
X
o
o
ID
O
(O
to
5-
4-
3-
2H
V
°v
\
ACTIVATED SLUDGE
OCT. 3,1967
O.I30mg 02/mgVSS-DAY
AT 16° C.
w
\
•
X
10 20 30 40 50 60 70
8
AERATED LAGOON
OCT. 3, 1967
AVERAGE = 0.274mg02/mg
VSS-DAY AT 16° C.
10 20 30 40 50 60
5-
\
<
4-
3-
2-
0.250mg 02/mgVSS-DAY
AT 16° C.
\
o.
\
\
\
\
\
AERATED LAGOON
OCT. 9, 1967
\
\ 0.275 mgOjj/mgVSS- DAY
\Q AT 20° C.
\>
10 20 30^ 40 50 60~
0.166 mg 02/mg VSS- DAY
AT 16° C.
ACTIVATED SLUDGE
OCT. 9, 1967
0.185 mg 02 /mg VSS- DAY
v AT 20° C.
10
20 30 40 50
FIG. D-3.
TIME - MINUTES
OXYGEN UPTA K E RATE
-------
U)
H
>
5-
°* /i
e 4-
z 3-
UJ
o
X
0 1-
0-
o (
^CL 0.142 mg O^/mg VSS-DAY
°X0 AT 20° C.
^\ ACTIVATED SLUDGE
°0v OCT. 10, 1967
^^3
. AERATED LAGOON ^o.
So* OCT. 10, 1 967 °NV
^^bv 0.263 mg 02/mgVSS-DAY ^Q
°VAT 20° C. xa
«n_ OL
nQ^ ^^
D 5 10 15 20 25 30 35 40
ID
•> _ 1
o
co 6-
co
5 4-
2-
o.
k
>NQX^0. 199'mg 02/mg VSS-DAY
Xgx^ AT I6°C.
°xVX\v AERATED LAGOON
^xT^o^ OCT- I4i l967
0. 24 8 m g 02/m g VS S^X
DAY AT 20° C. °N^
10 20 30 40 50 60
FIG. D-4.
8-
_
0.195 mg Og/mg VSS-DAY
AT 20° C.
X
ACTIVATED SLUDGE
OCT. 14, 1967
°N^
O.I3lmg(VmgVSS:o\ °\
DAY AT I6°C.
10 20 30 40 50
0.103 mg 02/mg VSS- DAY
AT I6°C.
ACTIVATED SLUDGE
OCT. 18, 1967
DAY AT 20° C.
10 20 30 40 50
TIME - MINUTES
OXYGEN U PTAKE RATE
-------
ro
"w
^%
E
z
Ul
o
X
0
o
UJ
o
o
£V 0.292 mg 02/mgVSS-DAY
1
6-
4-
2-
0-
r^k. U^.
xo^cx AT 16° C.
Ov X
°NoXo>. AERATED LAGOON
V^°v OCT- I8» l967
X °\
0.339 mg Og/mgVSS^n ^s
DAY AT 20 ° C. ^S
0 10 20 30 40 50
8-
<
6-
(
4-
2-
0-
, 0.205mg 02/mgVSS-DAY
^o^ AT 16° C.
\^ \0 AERATED LAGOON
\0 OCT. 28, 1968
\. °
^X. °x.
^o^ ^o
0.221 mg 02/mgVSS9\
DAY AT 20 °C. S,
0 10 20 30 40 50
'.I.
TIME -
8'
6-<
4-
2-
0-
^0 0.105 mg 02/mgVSS-DAY
^b^0 AT I6°C.
»V» ^"^o
0>N^ ^°-o^
^^0^ ^^0^
^o.
^^
°^n
°\
0.131 mg 02/mgVSS- °*>
DAY AT 20 °C.
0 10 20 30 40
«
6-
4-
2-
0-
^
ACTIVATED SLUDGE
OCT. 28, 1967
v»
50 60
1 0.066 mg02/mgVSS-DAY
\°-*o^ AT I2°C.
ov °^°-^o ACTIVATED SLUDGE
^5V °^o OCT- 3|i l967
x ^***o ^ O.I33mg 02/mgVSJ
^x^.
\0
o
\
AERATED LAGOON °V
OCT. 31,1967 MV
0.249mg 02/mgVSS-DAYX
AT 16° C.
i i 1 1
0 10 20 30 40
MINUTES
>PAY AT 16° c.
°\
O>VOL
^V-^
^s.
Ill
50 60 70
Fl 6. D- 5.
OXYGEN U PTA K E RATE
-------
12-
N
8-
V.
o> 6-
E
i
4-
z
u
o 2-
X
o
0-
H (
U> v
10-
QV 0.214 mg 02/mg VSS-DAY 8'
\ AT 20 °C.
^\ 6
o ACTIVATED SLUDGE
>> SEPT. 19, 1968
\Q 4
^v
X
°\
\
°\ 0-
o
o
o^ 0.177 mg 02/mg VSS-DAY
°v AT 1 6 ° C.
\. ACTIVATED SLUDGE
X SEPT. 28, 1968
o
\
\
o
\
Q.
) 10 20 30 40 50 ' 60 "° I0 20 3'° 4'°N 5'0
(jO
o 8-
UJ S
!j 6~
o
C/) 4_
(O
° 2-
n-
<
ko95 mg 02 /mg VSS-DAY
AT 16° C. 6-
X
\ACTIVATED SLUDGE 4-
OCT. 5, 1968
\> 2-
o»
^s» o
i
\ 0.139 mg 02/mg VSS-DAY
\r 12° c.
ACTIVATED SLUDGE
°v OCT. 16, 1968
\
\
\
0 10 20 30 40 50 0 10 20 " 30 40 50
TIME - MINUTES
FIG. D-6. — OXYGEN UPTAKE RATE
-------
H
U)
10-
8-
—
^ 6-
o>
E
4-
z
o 2-
x o-
\ AERATION BASIN
\ 0.164 mg 02/mgVSS-DAY
\ AT I6°C.
\
\
\ CONTACT STABILIZATION
v AERATION BASIN
\ 0.141 mg 02/mg VSS-DAY
^ °v AT 16° C.
°\ \ CONTACT STABILIZATION
o. \ OCT. 26, 1968
\ \ OVERALL RATE
\\ = 0.129 mg 02/mgVSS-DAY
o \
V-\— RE AERATION BASIN
o °vp.092mg02/mgVSS-DAY
\ \ AT 16° C.
O Ov
1 1 ^. I ^V 1 1
0 10 20 '30" 40 50
10-
<
8-
-
4-
2-
0-
N,Q 0.068 mg 02 /mgVSS -DAY
NX. AT 12° C.
°*v
^v»
^NO
Xo ACTIVATED SLUDGE
>o NOV. 8, 1968
o
°\
°\
0.109 mg 02/mgVSS-DAY o
AT 16° C. \L
c^
6 10 20 30 40 50 60 ^70
1 N U T E S
Fl
G. D-7.
OXYGEN
UPTAKE RATE
-------
U)
VJ1
10-
8-
6-
i 4-
z
Ul
o 2-
o
UJ
o
(O
0.057mg02/mgVSS-DAY
AT I2°C.
ACTIVATED SLUDGE ^o
NOV. 13, 1968
0.104 mg 02/mgVSS-DAY
AT 16° C.
0
,4
12
8-
6-
0.072mg 02/mgVSS-DAY
ACTIVATED SLUDGE
DEC. 6, 1968
AT I2°C.
4-
2-
10 20 30 40 50 60 70 \
I02mg 02/mgVSS-DAY
AT 20° C.
0 0.065mg02/mgVSS-DAY
AT 16° C.
ACTIVATED SLUDGE
NOV. 22, 1968
10 20 30 40 50 60 70
20-
16-
12-
8
02/mgVSS- 6_
AT 16° C.
0.063
02/mgVSS-DAY
AT I2°C.
ACTIVATED SLUDGE
DEC. 20, 1968
.080mg02/mgVSS-
AT 16° C.
0.12 mg 02/ mgVSS-DAY
AT 20 °C.
0 20 40 60 80 100 120 140 o 20 40 60 80 100 120
TIME - MINUTES
FIG. D- 8. OXYGEN UPTAKE RATE
-------
As the Nation's principal conservation agency, the Department of the
Interior has basic responsibilities for water, fish, wildlife, mineral, land,
park, and recreational resources. Indian and Territorial affairs are other
major concerns of America's "Department of Natural Resources."
The Department works to assure the wisest choice in managing all our
resources so each will make its full contribution to a better United
States-now and in the future.
DAST-8
------- |