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Other publications in the
FWPCA Publication No. I
Industrial Waste Profile series
.W.P.- 1:
FWPCA Publication No. I.W.P.- 2:
FWPCA Publication No. I.W.P.- 3s
FWPCA Publication No. I.W.P.- 4:
FWPCA Publication No. I.W.P.- 5:
FWPCA Publication No. I.W.P.- 7:
FWPCA Publication No. I.W.P.- 8:
FWPCA Publication No. I.W.P.- 9:
FWPCA Publication No. I.W.P.-10:
Blast Furnace and
Steel Mills
Motor Vehicles and
Parts
Paper Mills
Textile Mill Products
Petroleum Refining
Leather Tanning and
Finishing
Meat Products
Dairies
Plastics Materials and
Resins
FWPCA Publication No. I.W.P.-6
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THE COST OF
CLEAN WATER
Volume III
Industrial Waste Profiles
No. 6 - Canned and Frozen Fruits and Vegetables
U. S. Department of the Interior
Federal Water Pollution Control Administration
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C., 20402 - Price $1,25
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iii
PREFACE
The Industrial Waste Profiles are part of the National Requirements and
Cost Estimate Study required by the Federal Water Pollution Control Act
as amended. The Act requires a comprehensive analysis of the require-
ment and costs of treating municipal and industrial wastes and other ef-
fluents to attain prescribed water quality standards.
The Industrial Waste Profiles were established to describe the source
and quantity of pollutants produced by each of the ten industries stud-
ied. The profiles were designed to provide industry and government
with information on the costs and alternatives involved in dealing ef-
fectively with the industrial water pollution problem. They include
descriptions of the costs and effectiveness of alternative methods of
reducing liquid wastes by changing processing methods, by intensifying
use of various treatment methods, and by increasing utilization of
wastes in by-products or water reuse in processing. They also describe
past and projected changes in processing and treatment methods.
The information provided by the profiles cannot possibly reflect the
cost or wasteload situation for a given plant. However, it is hoped
that the profiles, by providing a generalized framework for analyzing
individual plant situations, will stimulate industry's efforts to find
more efficient ways to reduce wastes than are generally practiced today.
Commissioner
Federal vTSter Pollution Control Administration
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INDUSTRIAL WASTE PROFILE
CANNED AND FROZEN FRUITS AND VEGETABLES
Prepared for F.W.P.C.A.
FWPCA Contract Number 14-12-101
June 30, 1967
Federal Water Pollution Control Administration
September 1967
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iv
SCOPE
The scope of material included in this profile report
conforms to the requirements of the United States Depart-
ment of the Interior Federal Water Pollution Control
Administration Contract Number 14-12-101. Within the
available 90 day study period, engineering and economic
data has been critically studied by means of a total
industry approach. The relationship of the product to
the alternative sub-system manufacturing processes has
been reviewed in the field and office with responsible
industry representatives. The cognizant professional
associations and industrial experts have presented their
data and viewpoint, and have reviewed our draft information.
Key plant managers have cooperated in allowing limited
spot checks of their plant subprocesses and waste sampling.
The literature has, of course, been completely reviewed.
Because of the wide diversity of plants and processes,
we have attempted to achieve a comprehensive overview of
the approximate subprocesses. We have evaluated the
total relationship of products produced, waste pollution
load, economics involved, and long term environmental
quality factors.
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INDUSTRIAL WASTE PROFILE
CANNED AND FROZEN FRUITS AND VEGETABLES
TABLE OF CONTENTS
Section Title Page
1. PREFACE iii
2. SCOPE iv
3. TABLE OF CONTENTS v-ix
4. SUMMARY 1
5. CANNED FRUITS AND VEGETABLES 7
INTRODUCTION 8
I. PROCESSES AND WASTES 10
A. Fundamental Processes 10
B. Significant Pollutants 16
C. Process Water Reuse - 1964 17
D. Subprocess Trends 19
E. Waste Control Problems 25
F. Subprocess Technologies 25
II. GROSS WASTE QUANTITIES 28
A. Daily Waste Quantities 28
B. Wasteload Production Rates 33
C. Total Wasteload 33
D. Total Wasteload Projections 33
E. Seasonal Variations 34
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VI
(Table of Contents - cont'd)
Section Title Page
III. WASTE REDUCTION PRACTICES 40
A. Processing Practices 40
B. Treatment Practices 40
1. Removal Efficiencies 40
2. Rates of Adoption 49
3. Discharge to Municipal Sewers 50
C. By-Product Utilization 51
D. Net Waste Quantities-1963 51
E. Projected Net Waste load 52
IV. COST INFORMATION 54
A. Existing Facilities Costs 54
B. Processing and Treatment Costs 54
V. LIST OF TABLES
I Canned Fruit and Vegetable Pack 9
1-1 Subprocess Trends 21
II-l Daily Waste Quantities 29
II-2 Distribution of Load from 31
Tomato Processing Waste Stream
II-3 Typical Canning Wastes 35
II-4 Canning Season - Fruits 38
II-5 Canning Season-Vegetables 39
III-l Process Pollution Reduction 41
III-2 Treatment Removal Efficiencies 42
III-3 Anaerobic Fermentation of 48
Cannery Wastes
III-4 Projected Net Wasteloads 53
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vii
(Table of Contents - cont'd)
Section Title Page
IV - 1 Costs -Small Plant, Old Technology 5$
IV - 2 Costs-Medium Plant, Old Technology 57
IV - 3 Costs-Large Plant, Old Technology 53
IV - 4 Costs-Small Plant, Prevalent 59
Technology
IV - 5 Costs-Medium Plant, Prevalent 60
Technology
IV - 6 Costs-Large Plant, Prevalent 61
Technology
IV - 7 Costs-Small Plant, New 62
Technology
IV - 8 Costs-Medium Plant, New 63
Technology
IV - 9 Costs-Large Plant, New 64
Technology
IV -10 Summary of Production and 65
Waste Treatment Costs
7. FROZEN FRUITS AND VEGETABLES 66
INTRODUCTION 67
I. PROCESSES AND WASTES 69
A. Fundamental Processes 69
B. Significant Pollutants 74
C. Process Water Reuse - 1964 74
D. Subprocess Trends 75
E. Waste Control Problems 79
F. Subprocess Technologies 79
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viii
(Table of Contents - cont'd)
Section Title Page
II. GROSS WASTE QUANTITIES 80
A. Daily Waste Quantities 80
B. Wasteload Production Rates 83
C. Total Wasteload 83
D. Total Wasteload Projections 83
E. Seasonal Variations 83
III. WASTE REDUCTION PRACTICES 84
A. Processing Practices 84
B. Treatment Practices 84
1. Removal Efficiencies 84
2. Rates of Adoption 84
3. Discharge to Municipal Sewers 84
C. By-Product Utilization 84
D. Net Waste Quantities - 1963 85
E. Projected Net Wasteload 85
IV. COST INFORMATION
A. Existing Facilities Costs 87
B. Processing and Treatment Costs 87
V. LIST OF TABLES
X Frozen Fruits and Vegetables
Pack 68
I - 1 Typical Examples of Vegetables 72
Freezing Processes
1-2 Subprocess Trends 76
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ix
(Table of Contents contd1)
Section Title Page
II - 1 Daily Waste Quantities 81
III - 1 Projected Net Wasteloads 86
IV - 1 Summary of Production and gg
Waste Treatment Costs
8. LIST OF PLATES
1. Process Flow Chart - General 89
2. Process Flow Chart - Peach Cannery 90
3. Process Flow Chart - Tomato Cannery 91
4. Process Flow Chart - Olive Cannery 92
5. Process Flow Chart - Citrus Cannery 93
6. Waste Treatment Flow Chart 94
9. SPECIFIC BIBLIOGRAPHY 95
10. APPENDICES
I. GLOSSARY 97
II. GENERAL BIBLIOGRAPHY 101
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INDUSTRIAL WASTE PROFILE SIC 2033 SIC 2037
CANNED AND FROZEN FRUITS AND VEGETABLES
SUMMARY
This industry is one of the most important to the people of the
United States because 1) its total annual retail value today
exceeds $5 billion for canned food and $3 billion for frozen
food; 2) it utilizes great quantities of water - in 1964 alone
the 'pack1 of 944 million equivalent cases of canned and frozen
fruits and vegetables required 76 billion gal of water; and 3)
the raw materials are grown almost exclusively within our
country, are processed here, and fulfill almost all of our
domestic consumption needs.
The production of canned fruits and vegetables has increased
about 35 percent in the last 15-16 years. Frozen fruit and
vegetable production increased 300 'percent during the same
period, largely due to the expanded market for frozen vegetables.
There are many reasons for this change. The most important are
public acceptance of frozen products and more efficient and
economical methods of keeping the products frozen during
transport and marketing.
It is an understatement to describe the industry as diversified.
Literally dozens of entirely different raw and partially prepared
products are processed in more than 3150 plants. Of these, about
2000 can or freeze fruits and vegetables. Each plant may produce
a variety of canned or frozen products. For the purposes of this
report production has been subdivided as follows:
1. Canned fruits and vegetables
2. Frozen fruits and vegetables
As shown in the Process Flow Chart accompanying this study, the
Initial Preparation, common to all raw products, involves pre-
cleaning, size grading, and sorting. The purpose of these
initial processes is to remove unwanted and undesirable material
from the food before it undergoes processing. Wastes from this
operation often include soil, sand, stones, insecticides, dried
plant juices, vegetation, insects, and other residues. These
impurities are generally soaked and/or spray-rinsed off the raw
product, although a limited amount of air cleaning has been used.
The amount of impurities obtained in this process depends upon
the type of harvesting (hand or machine-picked) and the degree
of cleaning in the production line. The current trends are toward
mechanically-picked raw products which contain more soil and
other foreign matter, and higher product specifications calling
for more complete cleaning. Both trends are additive and encourage
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higher wastewater volumes and pollutional loads. Size grading
is usually done with screens, belts or other separators. Sorting
is usually a hand operation and primarily affects the quantity
of solid wastes to be removed from the premises.
The following processes are included in initial preparation:
trimming, coring and pitting, cutting, peeling, inspection, and
grading. However, not all raw products are processed by each
of the steps.
While trimming is mainly a hand operation, some liquid and solid
wastes originate ffom this operation. Coring and pitting,primarily
fruits, is generally a mechanical process resulting in a solid
residue usually disposed of on land. The cutting operation emits
some liquid waste primarily from product juices and equipment
wash water. Peeling of the skin can be done by hand, steam,machines,
or chemicals. The last two methods are most common and produce a
considerable volume of wastewater and high loads of BOD. A major
percentage of the wasteload is derived from chemical peeling opera-
tions which are used by plants processing peaches, tomatoes, and
other products requiring skinning. The raw products are immersed
for certain periods of time in hot lye solutions which literally
dissolve the skin of the fruit. The lye solution is usually piped
to storage containers for reuse. The peeled raw product is rinsed
with water upon emerging from the lye bath. The waste discharged
from the lye peel rinse is highly alkaline, hot, highly mineralized,
and contains a considerable amount of dissolved organic matter. In
many canneries and frozen food plants this one waste represents the
largest single source of BOD and suspended solids. After grading
and inspection, the final step in Initial Preparation, is transporta-
tion, usually by belt conveyors or flume, to the Converted Product
Handling processes. Water fluming requires less maintenance, is
less costly to operate, and serves to protect and rinse the product
during transportation. However, if flume water is discharged with-
out extended reuse, it represents a large volume and percentage of
total wastewater. It may contain a significant amount of total
plant BOD and suspended solids.
The first eight processes, plus plant clean-up from these operations,
often contribute about 50 percent of the total plant wastewater
volume, a major portion of the plant BOD, and, except in isolated
cases, virtually all of the suspended solids.
Converted Product Handling of canned fruits and vegetables involves
some or all of the following processes: blanching, mixing and adding
syrups and brine solutions, pulping, straining, cooking in vats, can
filling, exhausting and sealing, thermo processing, can cooling, and
storage. In addition, the equipment and floors of this portion of
the cannery are usually cleaned either continuously, at the end of
each shift, or at the end of each day.
The blanching process is of major importance. The blanching opera-
tion exposes the product (mostly green vegetables) to steam or hot
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water for a short period of time. This retards the degradation
of the organic matter by its enzymes. The waste from blanching
is hot and contains a considerable amount of dissolved organic
matter. Some products which are referred to as formulated
products, are further processed by pulping, straining, and/or
cooking in vats. Syrups, spices, juices, or brine are added as
required. Then the product is generally ready for filling into
cans. Only spillages or spoiled solutions cause waste during
this step.
Little waste originates from these processes except when equip-
ment is washed. However, when the pulp is wasted as in the
production of canned fruit juices, disposal of the pulp and
strained solids becomes a solid waste problem.
Insignificant quantities of waste from the product itself arise
from can exhausting, sealing, thermoprocessing (sterilizing), and
can cooling. However, since cans are usually cooled by water,
considerable waste water is generated in this step. This water
is relatively clean and is rapidly finding reuse in flume trans-
porting, raw product rinsing, and can cooling.
The Converted Product Handling processes for frozen fruits and
vegetables are generally categorized as blanching, washing,
cooling, final preparation and inspection, packing, and freezing.
Certain products are frozen on belts prior to packing. By far
the most significant waste here is the one from the blanching
operation.
Generally, the final steps in preparing frozen fruit juices are
extraction, screening, deoiling, deaeration, pasteurization and
concentration, packing, and freezing. The extraction and
screening processes are generally mechanical; e.g., halved oranges,
lemons, or grapefruits are pressed and squeezed to remove the
juices. Tremendous quantities of solid residues and some liquid
wastes result from this operation. Deoiling is accomplished at the
same time as deaeration. Since oil is objectionable, deaeration is
required to retard decomposition and off-tastes in the juice. If
the steam used in the evacuator is condensed to avoid air pollution
problems, a liquid waste containing dissolved contaminants results.
Generally, none of the other processes in freezing produce major
amounts of liquid wastes. Freezing is either slow or rapid.
Rapid freezing is usually preferred because it permits less change
in the juice product.
Canning of juices requires several of the same processes as freezing;
these are extraction by mechanical means, screening and clarification
of certain juices, flash pasteurization, mixing of additives, and
packing. The quantity and characteristics of the wastes are
generally similar to those discussed above for freezing of concen-
trated fruit juices.
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The quantity of wastes from each operation, in terms of both
flow and organic load, is variable and primarily a function of
the fruit or vegetable being processed. Cooling water appears to
be the largest volume contributor, while lye peeling operations
are usually very high in volume and BOD. Blanching is also a
major source of the wasteload. A consistent source of liquid
waste originates in the initial preparation processes, account-
ing for about one-third of the total wastewater volume and a high
percentage of the organic load.
Water consumption and wastewater discharge statistics for the
industry reflect some interesting trends. In the five year span
from 1959 to 1964, the wastewater discharge decreased an
estimated 10 percent while production increased about 11 percent.
The reason for this is the greatly increased volume of water
recirculated and reused, especially in areas where fresh water is
relatively expensive and/or sewer charges have been imposed based
on the volume of wastewater discharged. Location of the plant is
obviously an important factor; for example, canneries located in
California reuse more water than do frozen food plants in the South-
eastern United States. It is felt that a great deal more progress
can be made in water reuse by promoting its benefits to those plants
not now utilizing modern reuse practices and by increased control
instrumentation in existing water recirculation systems. An example
of the latter problem is the practice of designing plants for maximum
raw product capacity without installation of water control instrumenta-
tion to reduce water consumption when the plant is operating at less
than full capacity.
Based on the industry growth projected by the Business and Defense
Services Administration, U.S. Department of Commerce, production
will increase at the rate of approximately 3 percent per year during
the next 10 years. If such growth occurs, it is highly probable
that the wastewater discharged must increase in spite of higher in-
plant water reuse.
Census Bureau figures, as well as some rather thorough and recent
plant surveys, indicate that the expected average volume of waste
is about 80 gal per case (equivalent to 24 No. 303 cans). This per
case volume includes wastes from processes, cooling and condensing,
boiler feed, sanitary services, and all other uses. The average
per case wasteload contains about 0.70 Ib of BOD, 0.80 Ib of SS,
and 0.75 Ib of TDS for cannery wastes.
Since most processing occurs during a 2 to 4 month summer period,
the loads projected onto the Nation's watercourses and municipal
waste treatment plants during this peak period are a heavy burden.
The majority of canneries and frozen food processing plants provide
minimal treatment prior to discharging into municipal systems,
generally virbating screens to remove solids.
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Segregation and concentration of food processing wastes, and
recycling of process fluids, can reduce total water consumed
and improve the solids removal efficiency of pretreatment works.
Pre-treatment of wastes containing chemical constituents that
are complex, or not readily bio-degradable or are odorous, highly
acidic, basic, or otherwise toxic may require special additional
costly pre-treatment facilities. Chemical-mechanical facilities
involving such processes as precipitation, flotation, scrubbers,
neutralization tanks, and other processes can be used to produce
an effluent with more acceptable bio-degradable characteristics.
The conversion of wastes into a useful resource or alternatively,
the modification of the waste producing subprocess to reduce
waste, is a generally desirable goal.
Since canning and frozen food processing wastes are largely
organic, they are compatible to combined treatment with municipal
sewage if the following conditions exist:
- the treatment plant has adequate capacity and is of the
proper design to cope with the shock organic loads likely
to occur during the relatively short canning season.
- the cannery waste is properly pretreated to prevent slug
discharges of hot, alkaline, solids-laden wastes. Usually
this can be accomplished by a combination of adequate
screening and equalization.
In many municipalities, however, the treatment plant is inadequate
to cope with the large seasonal volumes of food processing wastes.
The resulting drop in treatment efficiency may cause serious
pollution in the receiving waters. This is especially true when
the receiving watercourse is flowing at a below average rate;
e.g., California rivers during the summer.
There have been changes in the character of modern canned and
frozen food processing plants. Whereas twenty years ago the
average plant was relatively small, handled one or two products
during a few months of the year, and was located outside the
large cities; today the average plant is large, more diversified,
handles a greater variety of raw materials, functions over a
longer period, and is being enveloped by spreading urban develop-
ment. The modern plant, which requires large quantities of water
and discharges large volumes of waste, has had a heavy impact on
its urban environment. The cities which have built up to and
around the canneries have generally inherited both the need to
supply their water and to treat their wastes. When handled
properly, these needs have been met and solved. Currently, it is
estimated that about 62 percent of the industry's waste is handled
by municipal facilities. For 1982, the percentage is projected to
be at least 74 percent. At that time the industry may attempt to
move closer to the agricultural sources.
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There is a definite trend toward increased sewer use charges
by municipalities to industries discharging large volume and/or
heavily polluted waste waters. The two paramount reasons for
this are to stimulate industry to reduce its wasteload discharge
and because this industry in common with other wet industries
has generally been paying less than its proper share of the cost
of collecting and treating its wastes.
An estimated 38 percent of the industry's wastes are disposed of
by other means than discharge to municipal sewers. In a recent
survey it was found that only one-third of these plants provide
waste treatment more extensive than screening. Oxidation ponds
and spray irrigation systems were the predominant methods of
secondary treatment. The national effort to reduce pollution
will create standards for most watercourses in the near future.
It is anticipated that the rigorous enforcement of these standards
will force most of those plants not now providing adequate treat-
ment to either connect to a municipal system or construct efficient
facilities.
Based on figures released by the Business and Defense Services
Administration, U.S. Department of Commerce, the production costs
(value added) for canning and freezing of fruits and vegetables
average approximately $1.66 per equivalent case. In-plant waste
treatment costs average approximately $0.006 per case exclusive
of sewer service charges, or 0.4 percent of production costs.
Sewer use charges average about $0.008 per case. Thus, the total
out-of-pocket cost to a typical plant may average about $0.014 or
0.9 percent of its production cost, exclusive of taxes or assess-
ments.
On a national basis it is estimated that waste treatment costs
this industry approximately 2 percent of value added in manufacture.
This 2 percent includes in-plant treatment facilities and that
portion of industry's taxes attributable to municipal pollution
reduction, exclusive of collection system services.
The canning and frozen food industries have many similarities and
common problems; however, national statistics reveal several
significant differences. The frozen food industry generates
approximately twice as much waste water volume per equivalent
unit of production as does the canning industry. The amount of
pollution load generated per equivalent unit of production however,
is approximately the same. The reasons for this difference in
volume are that the frozen food processers use larger volumes
of cooling water; they are generally located in more abundant
water areas; and a much smaller percentage of them discharge to
municipal sewers. These factors result in an absence of incentive
for the frozen food processers to introduce water conservation
techniques into their plants.
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Industrial Waste Profile
Canned Fruits and Vegetables - SIC 2033
U. S. Department of the Interior
Federal Water Pollution Control Administration
I. W.P. No. 4 - Canned Fruits and Vegetables
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8
INDUSTRIAL WASTE PROFILE STUDIES
CANNED FRUITS AND VEGETABLES
SIC 2033
INTRODUCTION
In the United States today, more than half of the
vegetable crops and nearly half of the fruit crops are being
processed, either by freezing or canning. The trend toward
processing is still increasing. Food canning plants are located
in 49 of the 50 states, Puerto Rico, and the Virgin Islands.
Nearly 2000 canneries, producing every basic type of
canned food, process over 1200 different food items, either
singly or in combination. In 1966, the retail value of the
total canning pack was more than $5 billion.
This profile is limited to a study of the canned fruit
and vegetable industry which comprises approximately 60
percent of the total production, with a production value of
approximately $3.9 billion. It excludes meat and fish, as well
as special items such as soups, baby foods, fruit pies, jams
and jellies, and pickled specialties.
Table I (*•) (2) depicts the growth of the industry
from 1950 to 1966. A case is equivalent to 24 No. 303 cans;
i.e., 24 No. 2-% cans were assumed equivalent to 1.77 cases
of No. 303 cans, etc.
Because of the diverse nature of the products and the
individuality of each processing plant, it would be impossible to
describe each of a multitude of process schemes. However, for
the purpose of this report, processes will be generalized for
broader evaluation.
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TABLE I
CANNED FRUIT AND VEGETABLE PACK
Year
1950
1954
1963
1965
1966
per
Million
wt, Ib
equiv .
cases of
#303
retail
value $
wt, Ib
equiv .
cases of
#303
retail
value $
wt, Ib
equiv .
cases of
#303
retail
value $
wt, Ib
equiv .
cases of
#303
retail
value $
Canned
Fruit
2880 3
120
N.A.
36203
151
477
42503
177
751
45203
188
N.A.
Canned
Vegetables
55103
230
N.A.
59003
246
740
7250 3
302
1134
76203
318
N.A.
Cannei
Juice
21603
90
N.A.
19203
80
261
17103
71
472
19823
83
N.A.
1. 1966 pack statistics except where the latest available information
2. Exclusive of plums was 1965
3. At 24/lb/case of #303 cans
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10
INDUSTRIAL WASTE PROFILE STUDIES
CANNED FRUITS AND VEGETABLES
SIC 2033
I. PROCESSES AND WASTES
A. Fundamental Industry Processes
Due to the diverse nature of the products handled by this
industry, a multitude of process schemes could be described. Each
cannery is probably unique in its inhouse process. However, for
the purposes of this report, processes will be generalized into the
following categories:
1. Preliminary Cleaning and Preparation
2. Canning of Fruits and Vegetables
3. Canning of Juices
Meat and fish processing are not included in this study, nor
are the canning of specialty items, jams and jellies, or pickles.
Wherever possible, important subprocesses associated with
specific fruits and vegetables will be described in detail. An
overall schematic diagram of the major processes is to be found in
Plate 1 (Process Flow Chart). Four additional simplified typical
flow charts for major segments of the food processing industry are
shown as Plate Nos. 2 to 5.
1. Preliminary Cleaning and Preparation
Raw products intended for commercial canning must be cleaned.
The procedures of cleaning vary with the nature of the food; but all
raw foods must be freed of adhering soil, dried juices, insects, and
chemical residues. This is accomplished by subjecting the raw foods
to water baths and high-pressure water sprays while being conveyed on
moving belts or passed through revolving screens. Product wash waters
may be fresh or reclaimed from an in-plant operation, but should be
of suitable quality. The wasted wash waters contain, in soluble and
suspended form, the contaminants removed from the raw product, and
juices and fragments of the product being washed.
Important factors affecting the preliminary cleaning process
are the method of harvesting, whether field washing is practiced, and
the care taken to protect the raw product from damage during trans-
portation from field to cannery. The increasing use of harvesting
machines has caused a dirtier raw product containing more debris,
leaves, vines, damaged produce, etc. than did the older, hand picking
methods. Preliminary washing of the raw product in the field greatly
reduces the pollution generated by the cannery, but unfortunately
this is not a prevalent practice.
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11
a. Pre-cleaning and inspection; These processes use both
"wet" and "dry" methods and also mechanical and hand operations.
Agitating by hand, screens, jets of air, and belt and roller systems
are examples of "dry" systems; while water (wash) spraying, flotation,
soaking, and fluming are 'Vet" methods.
Tomatoes, for example, are either discharged or dumped directly
by hand or mechanical means from the hampers or lug boxes into the
soak washer. The purpose of this operation is to loosen much of the
adhering soil and other contamination thereby reducing the load on
the spray washer. The product moves through the soak tank emerging
on a belt after 1-3 min (or more), and is washed by overhead spray.
This soak/wash operation gives large volumes of waste. Of the 4000
gal/raw ton tomatoes, 88d gal or 22 percent are used for removing the
soils and any other foreign matter on the product before further
processing. Total suspended solids may range from 180 to 1584 ppm.
Grapefruit, on the other hand, is spray washed with 2200 gph compared
with a total water use of 22,600 gph; i.e., less than 10 percent of
the water is used for washing.
Shelled peas are first cleaned. Three shaker screens are used
in the cleaner to remove pieces of pod and vine, fine dirt, and splits.
An air blast through which the peas fall takes out light extraneous
material. The peas are then put through a flotation washer where the
cold water washes away the vine juices and field dirt. Any skins,
splits, or other lightweight foreign material is removed by flotation,
while any sand or small stones and silt sink and are caught by
riffles. The peas then pass through a reel equipped with a fresh water
spray where the peas are separated from the wash water. Total sus-
pended solids in the wash water range from 270 to 400 ppm.
In addition to the cold water flotation washer, many canners
are now using a froth flotation cleaner. This cleaner operated on a
principal of difference in wettability between product and the
extraneous material. It has been found to be very efficient in
removing nightshade berries, thistle buds, weed seeds, etc. which
are less easily wet than peas so that they float out in the froth
emulsion while the product such as peas sink.
Sorting operations may select for size, maturity, weight,
quality, and/or other characteristics. With some food products
(such as peas) there is no sharp line between the sorting and pre-
liminary cleaning. Hand sorting at a "sorting table" remains the
method of choice and often combines cleaning and some preliminary
preparation.
The husking of corn by machine serves to clean, prepare for
processing, sort, and grade in one operation. The "sorting table"
may feature several belts or bins or chutes by which the product is
handled. Tomatoes use a variation of this method, including the
cutting and trimming of spoiled portions.
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12
b. Trimming. Coring. Pitting and Cutting; These operations
usually involve both mechanical and hand processing. Trimming is
usually a hand operation and frequently takes place at the sorting
table or nearby. Product portions are removed for size, weight,
quality, or processing needs.
Pears, apples, peaches, olives, cherries and apricots are
usually cored or pitted before processing. Coring and cutting of pears
and apples is a mechanical process. Peaches and apricots are cut into
halves by machinery as the pit is removed. Following the halving and
pitting operation, the fruit halves are inspected by hand. Halves from
which the pits have not been completely removed are segregated for
re-pitting.
c. Peeling; Peeling or skin removal of the product is also
an incidental form of cleaning. It can be accomplished by hand,
machine, or chemicals.
Mechanical or chemical peeling may be performed for apples,
pears, potatoes and other products. Some fruits such as potatoes,
beets, turnips, and carrots may be peeled in a cylinder whose walls
are abrasive in nature. The drum is rotated and water is introduced.
Formerly, soft fruits and vegetables, such as tomatoes, were
first scalded by steam or hot water and then peeled by hand. In most
modern plants, tomatoes, peaches, and other fruits are usually peeled
by immersion in a hot lye solution, or they may pass under a spray
or cascade of the same solution. For example, most clingstone peaches
on the Pacific Coast are lyepeeled. The peaches are dumped or conveyed
on an inclined conveyor belt into a lye peeler where the halves are
positioned cup side down and exposed to a heavy flow of 1% to 5 percent
lye solution at a temperature of about 210°F for 45 to 60 seconds.
The lye solution is recirculated to conserve caustic, lessening the
amount of lye waste. Many canners use wetting agents to facilitate the
removal of skins. The wetting agent is added directly to the lye
solution. Although the effectiveness of a wetting agent has been
somewhat controversial, it has been claimed that its use materially
reduces the amount of lye normally used. The first rinse water of
the skinned product is usually segregated to produce an effluent with
a high wasteload.
A major use of water is the rinse of chemically peeled fruits
and vegetables to remove excess peel and caustic residue. Water of
suitable quality is used for final rinse. This is reused in the initial
wash. The spent peeling solutions are strong wastes, high in organic
and inorganic content. Following removal of the peel, the fruit halves
are size graded on a shaker grader and then each size is inspected on
an inspection belt for off-color and imperfect fruit. These imperfect
units, which are unsuitable for halves or slices, are usually diverted
to pie stock or fruit cocktail.
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13
d. Product Preparation; This step is the final preparation
of the food material prior to transportation to specific secondary
operations such as canning, juicing, etc. It consists of several
independent operations. Some of the more complex operations require
considerable time, labor, and material. Post-sorting, by hand or
machine; specialized cutting such as dicing carrots and potatoes;
"finger slicing"; size grading; blending; and final inspection are
included in this category.
e. Transportation: Washed raw products are transported
to and from the various operations by means of belts, flumes, and
pumping systems. This is a major use of water. Although the fresh
water make-up must be of suitable quality, recirculation is practised
to reduce water intake. Chlorination is used to maintain certain
recycled waters in sanitary condition. Waste waters from the hydraulic
systems contain product materials in soluble and suspended forms.
f. Summary: These preliminary operations, including plant
cleanup, can use up to 50 percent or more of the total water used in
the canning industry, and they contribute the major portion of solid
wastes (screenings) associated with the overall process. Specific
values for water use, screenings, and wastes will be detailed in the
waste treatment portion of this report.
2. Canning of Fruits and Vegetables
The processes described herein are not necessarily meant to
operate in series or in the order indicated. Plate No. 1 Process
Flow Chart, shows the diversity of possible schemes.
a. Blanching: Blanching operations are designed to expose
the entire product (most green vegetables) to high temperatures for
a short period of time. The primary function of this operation is to
inactivate or retard bacterial and enzyme action which causes rapid
degeneration of quality. Although high sugar content in green peas is
a desirable quality, it makes them quite sensitive to sugar-substrate
enzymes. Other carbohydrases and proteinases create similar problems.
Secondary desirable effects of blanching include the expelling
of air and gases in the product, as well as the reduction of volume of
the product. Leaching of sugars, starches, and other soluble organic
compounds from the raw fruits or vegetables into the blanch water makes
it a very strong liquid waste when discharged.
Depending upon the product and/or availability of equipment,
blanching may be accomplished by immersion in hot water (180°-212°F),
or exposure to live steam.
b. Pulping and Straining; These operations are usually
carried out prior to cooking or, as in the baby food industry, after
heating and/or cooking.
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14
c. Cooking; Cooking and other types of heating are applied
to several types of foods. Tomato sauce, paste and catsup all require
heating (or cooking) with some salt, spice, or acid not included in
the usual processing flow.
d. Mixing and Adding; Other constituents are mixed with and
added to the main product. These additives are spices, thickening
agents, syrups, juices, water, salt, brine, etc. which will enhance
the product during heating operations.
e. Inspection and Packing; Final inspection operations
involve several sub-component operations depending upon the product.
Quantity as well as quality control procedures will cover product
examination, including batch quality/quantity control; rejection
re-routing; container portion control; total additives prior to
filling and sealing; weight control before and after container
packing; case packing control; and processing load.
Batch volume for container packing will usually determine
final additive characteristics and desired concentration. The addi-
tion to the product may be made either in the batch container or in
the container itself during packing/filling operations.
Metal cans, glass containers, 55 gal steel drums suitably
lined, and plastic-lined fiber-backed drums are used as containers.
These are commonly washed prior to use producing a waste water suitable
for reuse elsewhere in the plant.
After filling it is desirable to pass the sealed cans through
a hot water spray washer following closure to remove any adhering
product. It is important that the retorts or continuous cookers are
clean to avoid unnecessary cleaning of the cans after processing.
f. Thermo-process: Thermo-processing is the process in which
the sealed cans are exposed to high temperature for varying lengths of
time depending upon the nature of the product. The purpose of the
thermo-process is to render the product commercially sterile by killing
all bacterial spores which could spoil the product or cause illness
to the consumer. Once the containers are filled, inspected, sealed,
thermo-processed, cooled, dried and labeled, they are cased and ready
for shipping.
3. Canning of Juices
Following initial preparation, the first step in the canning
of juices is extraction. There are several methods, including the
following for citrus juices:
Rotary juice extraction - halved oranges are held in
depressions in rolls while
they are pressed by protu-
berances within lower rolls.
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15
FMC Inline extraction - oranges are pressed between
upper or lower intermeshing
multifingered extraction cups.
The Buron Machine - halved fruit is reamed
automatically.
Citro-Mat extraction - halved fruit is pressed
between rotating rolls, one
of which rotates twice as
fast as the other.
Extraction of tomato juice may be accomplished by several
different types of commercially available extractors. These include
either the screw type or paddle type extractors. Screw type extrac-
tors press tomatoes between a screw and screen. The perforations in
the screen vary but usually are about 0.02 to 0.03 inches in diameter.
Some installations are equipped with a shaker screen ahead of the
extractor where scald spots along with stems, cores, and other foreign
material can be removed.
For all juices, the extraction is followed by a screening
operation to remove pulp and seeds.
Citrus juices generally require deoiling which employs
heating to about 125°F in a heat exchanger maintained under a vacuum
of 26 in. The vapors containing the oil are condensed and run to a
decanter where the oil separates and is drawn off the top layer.
The lower layer is returned to the deoiler. About 80 percent of
the oil is removed in this process.
If deoiling is practiced, deaeration usually occurs at the
same time. Otherwise, deaeration is a separate operation. The
juice is introduced in a thin film or finely divided particles into
a vacuum chamber. Steam used in the evacuator is usually vented
to the atmosphere; if condensed, this liquid could contain some
pollutants.
If the juice is to be concentrated, it must first be pasteur-
ized. The preferred method of pasteurization is the use of heat
exchangers, either tubular or plate type. Juice should be heated
to 185°-200°F in a few seconds to inactivate enzymes and destroy
spoilage organisms, and then immediately concentrated.
The juice is concentrated in vacuum evaporators. In a
vacuum concentration, the water is removed by boiling at moderate
temperature under appropriate vacuum. Either a series of single
effect evaporators or multiple effect evaporators may be used.
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16
During vacuum concentrating, the volatile constituents
are largely removed. For some uses, it is desirable to replace
some of these constituents. This has been attempted in the past
by either condensing the initial distillate and fractionating to recover
some of the volatile constituents which are added back to the
concentrate, or by adding terpeneless orange oil.
Tomato juice is sometimes homogenized to produce a
thicker-bodied product and to prevent settling of the solids. The
general practice is to eliminate the homogenation particularly when
"hot break" juice is being packed. When homogenizers are employed
they are operated between 1000 and 1500 Ib per sq in of pressure at
a juice temperature of about 150°F.
B. Significant Pollutants
Waste materials that originate from fruit and vegetable
canning operations are of two classes: solid materials, such as
trimmings, pits, peels, leaves, stems, and defective whole pieces
that are discarded within the plant; and waste materials such as
sugars, starches, and other carbohydrate-like compounds exuded or
leached from the raw or cooked product and carried in solution in
the wash or flume waters used in preparing and processing the
food.
The total volume of waste materials, and the nature and
concentration of suspended and soluble organic materials in the
waste streams from food canning operations, vary widely with the
type of raw product being processed and with the methods employed
in individual plants. Aside from factors beyond the direct control
of the canner, such as the quality and maturity of the fruit or
vegetable, variations In the volume and pollution-potential of the
waste streams are caused by differences in rate of raw product
in-put, the extent of hydraulic transport of raw product, the degree
of recirculation of process waters, the extent of in-plant transport
of solid wastes, the general orderliness and good housekeeping
within the plant, and the effectiveness of the final screening of
the composite waste stream.
When untreated fruit and vegetable processing wastes are
discharged to a stream or other body of water, the ability of the
stream to assimilate the waste without showing evidence of pollution
depends largely on the relationship between the volume and strength
of the waste discharged at a given time and the volume and flow rate
of the receiving water. Carbohydrate materials in the food canning
waste can initiate rapid and abundant microbial growth in the re-
ceiving water. The most common and expected pollution effect is
depletion of the oxygen supply in the stream to the extent that fish
life is killed. If oxygen is used without replenishment, anaerobic
decomposition of the waste begins with production of odors, dis-
coloration of the stream, and other nuisance conditions.
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17
Thermal pollution is a possibility if waters from a container-
cooling operation or from a product evaporation-concentration system enter
streams before the heat has been dissipated.
Air pollution due to direct emission of volatiles or air-borne
particles has not been shown to require immediate attention. Furthermore,
there is no apparent possibility that unique air pollution hazards will
result from chemical or physical conversion of water-borne waste materials,
in terms of today's emission standards.
Significant pollutants in this industry arise from the follow-
ing operations:
1. Hot Lye Peeling
2. Sorting, Slicing, Cutting, Blending, Etc.
3. Processing
4. Washing (several washes are used in most plants)
5. Exhausting of Cans
6. Cooling of Cans
7. Plant Cleanup
8. Box Washing
The combined wastes have the objectionable characteristics of high BOD,
TDS, and suspended solids. The peeling, coring and blanching operations
supply particularly concentrated wastes.
C. Process Water Reuse - 1964
The state of the art in food processing plants appears to involve
continuous recirculation of waters with limited make-up and blow-down
for a particular subprocess. For example, wash waters for most produce
can be continuously recycled within an optimum system. Final rinsing
removes the residual dirty water and this serves as make-up for the
initial scrub washing subprocess. Similarly, flume water used for the
carriage of fruits and vegetables is continuously recycled and builds
up a high organic content. Low pH and appropriate bactericides can be
used as a means to control bacterial growth. The rinse spray is used
again to make up the flume water. Blow-down of the subprocess water
system and wash-up normally follow each shift.
Cooling tower recirculation is a common method of conserving
water. The cooling tower blow-down can be used for supply water with
the various subprocesses of the packing plant. Evaporator waters may
be reused for processes, especially washing, initial washing, etc.
The improved food handling subsystems also promote general
plant sanitation and conserve water by requiring less washdown water.
For example, culls are normally segregated at sorting belts,
and partially damaged fruit of good quality is transported to subprocess
where pulping for Juice occurs.
Better food process handling throughout the nation is result-
ing in lower labor requirements, less error, less waste and
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18
significantly increased production rates per gal of process water.
For example, a modern peach cutting machine is similar in design to
earlier equipment, but operates at higher rates, with less damage
to the fruit, and better cutting efficiency, thereby reducing the
solid wasteload. In summary, it can be said that the trend of modern
food processing plants is toward increased automation resulting in
improved efficiency, increased production per unit of plant area,and
less dependency on the seasonal labor force.
The increasing costs of water, and sewer service charges
based on flow volume and pollution content, are also acting as in-
centives to optimize the conservation and reuse of water within the
food processing industry. Recent surveys of eleven California
canneries indicate that water conservation and reuse can reduce water
use per unit of product up to 40 percent.
The following is a tabulation * 'of the industry's 1963
water intake, water use and reuse, and waste discharge for canned
fruit and vegetable processing plants throughout the nation.
It should be noted this tabulation does not include plants using
less than 20 MG/yr.
Item Water Quantity in Percent of Intake
billion gal/yr Quantity
Water Intake 35 100
Process 20 57
Cooling,Condensing 10 29
Boiler Feed 5 14
Sanitary service & Other
Recirculated Water 16 46
Consumption 2 6
Discharge 33 94
Only 239 of the 1600 canneries reported in the 1963 Census
of Manufacturers. Based on other statistics from the census, It
was calculated that the industry's total water intake and waste discharge
were as follows:
Quantity in billion gal/yr
Intake Discharge
Canned Fruits and Vegetables 40 38
It should be noted that these quantities include the wastes
generated by secondary processing in plants such as those producing
jams, jellies, and preserves packaged under the classification of
Canned Fruits and Vegetables SIC 2033. However, discussion within
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19
this report excludes these secondary-type processors. An independent
survey of several representative plants shows the following relatively
high reuse of water.
Recircu- Gross Liquid
Intake lated Applied Waste
11 California canneries 4220 (5) 3400 (100) 8300 (6) 3600 (3)
5 other canneries 4500 (8) 600 (3) 5100 (6) 3600 (6)
Tomato Cannery 4200 3400 7600 3600
Peach Cannery 5400 4000 9400 4500
Figures in parentheses are the ratios of the maximum to the minimum
estimates of the volumes.
The industry as a whole estimates that in 1966 approximately
50 percent of process water was reused at least once. In many
instances waters from certain processes are reused many times.
It is felt that a great deal more progress can be made in
water reuse by promoting its benefits to those plants not now utilizing
modern reuse practices and by increased control instrumentation in
existing water recirculation systems. An example of the latter
problem is the practice of designing plants for maximum raw product
capacity without installation of water control instrumentation to
reduce water consumption when the plant is operating below full
capacity.The volume of water used per unit of production increases
significantly when a plant is operating below its maximum capacity.
D. Subprocess Trends
Table 1-1 describes the predominating subprocess mixes for
the canned and frozen fruit and vegetable industry. The industry
is divided into two segments: Canned Fruit Juices, and Canned
Fruits and Vegetables. Figures shown are percentages of that
section of the industry noted using each subprocess. The total
percentage may be less than, equal to, or more than 100 percent
because many plants do not use all of the subprocesses shown while
others use several methods to accomplish one subprocess. Some of
the subprocesses are characteristic of only one segment of the
industry. For example, clarification is a subprocess used in the
production of clear fruit Juices. Therefore, the figures shown
reflect the percentage of that portion of the industry involved in
fruit juice production. Totals for any given subprocess may
increase or decrease due to the change in size of the segment of
the industry using the given subprocess relative to the rest of the
industry.
Insight into these processes was achieved by thoroughly
reviewing available literature, interviewing key personnel within
the industry, observing operations in several representative
plants, and analyzing production quantities given in the 1967
287-029 O - (
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20
Almanac of the Canning, Freezing, and Preserving Industries.
The tables consist of three sections as follows:
A) Initial Preparation
B) Canned Fruit Juices
C) Canned Fruits and Vegetables
In general, the subprocesses listed under Initial Preparation are
used by both segments of the industry. Those listed under the
other two sections characterize only that segment.
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21
TABLE 1-1
SUBPROCESS TRENDS
Fundamental Process and
Subprocesses
SECTION A - INITIAL PREPARATION
Field Clearing
Pre-Cleaning
1. Spray Wash, Rinse
2. Detergent Wash & Rinse
3. Water Soak Only
4. Water & Rinse Bath
5. Brine
6. Flume
7. Dry Cleaning
Sorting
1. Mechanical
a. Screening (size grad-
b. Flotation ing)
2. Hand
Trimming
1. Hand
2. Silking & Husking
3. Mechanical
Coring & Pitting
1. Hand
2. Mechanical
3. Kernel Cutter
Cutting
1. Slicing
2. Dicing
3. Halving
4. Snipping
Peeling
1. Steam Scalding
2. Hot Lye
3. Abrasion
4. Mechanical Knives
Percentage of Total Plants
1950 1963 1967 1972 1982
50 60
10
10
95
40
5
5
20
15
85
35
5
10
15 10
20 25
5 5
35 35
5 10
15 15
15 10
20 10
10 30
10 5
20 15
60
20
20
85
35
5
10
10
25
5
35
10
15
10
8
35
5
12
15
25
25
75
30
5
15
8
27
5
30
60 60
5
15
20
5
5
-
5
10
15
5
5
-
5
5
10
5
10
5
10
5
5
5
10
5
10
-
5
5
10
10
35
25
70
20
5
25
5
30
5
35 35
15 15
15 15
5 5
5 2
40 50
5 4
10 4
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22
Fundamental Process and
Subprocesses
SECTION A (cont'd)
Grading & Inspection
I. Eye
2. Photo-Med. Color
Transport
1. Primary Flume (Water)
2. Conveyor Belt
3. Cart/Truck/Hand
Product Waste Disposal
1. Floor Disposal
2. In-process Bin Collection
3. Conveyors
4. Floor Gutters & Flumes
Plant Clean-up
SECTION B - CANNED FRUIT JUICES
Extraction
1 . Crush/Press
2 . Reaming
3 . Pulping
Percentage of Total Plants
1950 1963 1967 1972 1982
1. Mesh Screen
2. Centrifuge
De-Oil
1. Heating in Vac.
Pe -Aerate
Clarification
1. Gelatin & Tannin
2. Pectic Enzyme
3. Flash Heating
4. Freezing & Thawing
100
"
45
75
10
5
30
20
100
100
10
25
65
40
30
15
1
5
8
5
2
100
"
60
80
8
3
20
10
100
100
10
25
65
40
30
25
1
3
13
2
2
98
2
65
85
6
2
13
10
100
100
10
25
65
40
30
30
1
2
15
1
2
95
5
70
90
3
1
9
20
100
100
10
25
65
40
30
32
1
1
17
-
2
85
15
70
95
2
5
30
100
100
10
25
65
40
30
35
1
1
17
-
2
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23
Fundamental Process and
Subprocesses
SECTION B (cont'd)
Pasteurization
1. Pasteurization Only
2. Pasteurization & Concentra-
tion
Solid Waste Product Handling
1. Floor Disposal
2. In-process Bin Collection
3. Conveyors
4. Floor Gutters & Flumes
Plant Clean-Up
SECTION C - CANNED FRUITS AND VEGETABLES
Blanching
1. Hot Water
2. Steam
Mixing and Adding
1. Syrup, Spice and/or Juice
Addition
2. Brine
3. Pulping & Straining
Vat Cooking
Filling
1. Hand
2. Mechanical
Can Exhaust
1. Mechanical Vacuum
2. Exhaust Boxes
3. Steam Flow
4. Hot Fill
Percentage of Total Plants
1950 1963 1967 1972 1982
90
10
5
25
20
45
100
TABLE
35
5
40
60
5
25
70
30
25
80
20
40
80
20
3
15
15
65
100
:s
35
5
40
60
5
30
50
50
25
60
40
40
80
20
2
10
18
70
100
35
5
40
60
5
32
40
60
25
50
50
40
75
25
10
20
70
100
38
4
40
60
4
35
25
75
20
40
55
35
70
30
5
30
65
100
38
3
40
60
4
40
10
90
15
30
65
30
Seal & Thermo Process
100 100 100 100 100
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Fundamental Process and Percentage of Total Plants
Subprocesses 1950 1963 1967 1962 1982
SECTION C (cont'd)
Can Cooling
1. Water 95 100 100 100 100
2. Air 10 10 1 10
Solid Waste Product Handling
1. Bin Collection 10 8 6 52
2. Floor Gutters or Flumes 55 72 82 75 65
3. Conveyors 25 15 10 20 33
Plant Clean-up 100 100 100 100 100
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25
E. Waste Control Problems
The canning industry is unusual in that the product
handled is in itself extremely bio-degradable resulting in a
waste which is among the strongest in terms of BOD of all indus-
tries. It has approximately ten times the strength of domestic
sewage. Due to the necessity of rejecting spoiled and overripe
portions of food, the canning industry produces a large amount
of solid wastes.
The rinse following chemical peeling (where used) can
contribute as much as 40 percent of the plant BOD. The waste
from this process is highly alkaline and may require neutraliza-
tion prior to biological treatment. In addition, a portion of
the product is dissolved by the lye and enters the waste stream.
Raw product washing is another major source of pollution.
In this process, all of the dirt, vegetation, and pesticide
residues are removed, often with the aid of detergents which
create an additional wasteload. On the other hand, the spray
rinse after washing requires a large amount of water (15 percent
of total plant water), but the pollutant content is low.
Plant clean-up is a secondary source of pollution. Most
solid matter reaching the floor accidentally, and spilled juices
and solid matter remaining on equipment are flushed into floor
drains.
F. Subprocesses Technologies
There has been no basic change in the series of sub-
processes used in the production of canned fruits and vegetables
since 1950. Most of the changes have been refinements and
optimization of older practices. These technological improve-
ments resulting in higher production rates and better product
quality have not reduced wasteloads to any great extent. The
trend toward increased use of flumes for product transport has
reduced the quantity of rejected food waste. Furthermore,
utilization of nozzles employing high pressure and low volume
will reduce rinse water requirements. Disposal of solids
reaching the floor by sweeping and collecting, followed by
nominal wet washing, can reduce wastewater volumes, BOD, and
suspended solids. Increased use of conveyors for dry disposal
of rejects and wastes may be employed more in the future to
conserve water and reduce the liquid wasteload.
An optimum plant design with complete water conserva-
tion and a good housekeeping program can reduce wastewater
volume by more than 50 percent.
The waste production of older, prevalent, and new
technologies cannot be specifically described. However, the
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26
trend is toward greater recirculation and reduced water intake,
resulting in a decreased volume of liquid wastes containing a
higher concentration of pullutants.
The industry reports increased use of field washing and
sorting stations, thereby eliminating these steps in the cannery.
This is highly beneficial in reducing pollution generated by the
canneries and should be strongly encouraged.
Chemical peeling is used increasingly. Unfortunately,
this process generally produces greater dissolved organic and
inorganic pollution than do the alternate mechanical processes.
Mechanical abrasion or knife peeling produces largely solid
wastes which are not discharged to the sewer.
A very complete discussion of plant sizes as related to
region of the country, raw product volume, and number of products
handled is contained in the U.S. Department of Agriculture,
Economic Research Service canner survey, 1965. It reveals that
in 1963 the average output per plant amounted to 371,648 case
equivalents of size 303 cans. The regional average varied from
152,000 case equivalents in the Eastern United States to 700,000
case equivalents in the Western United States.
Based on an arbitrary plant size classification of:
Small plant - less than 210,000 cases / year
Medium plant - 210,000 to 800,000 cases / year
Large plant - over 800,000 cases / year
The percentage of plants in each classification is
estimated as follows:
Small plant - 35 percent
Medium plant - 33 percent
Large plant - 32 percent
There is a definite indication that many of the small firms
are hard pressed to compete and that the percentage of small firms
will decrease in the future as a result. Many small firms are
discouraged from making investments in new plant equipment and
thus do not participate in the cost savings of modern production
technology.
As previously stated the principal difference between old,
prevalent, and newer technology in this industry is not in the
operational sequence, but rather in the speed and efficiency of
the machinery performing the operations. New production machinery
is generally very expensive and can only be justified by adequate
production volume; it follows, therefore, that in general the larger
plants fall into the newer and prevalent technology categories and
the small plants tend toward the older technology classification.
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27
It is estimated that the percentage of plants falling into
each classification is as follows:
Percent In Each Technology Classification
Plant Size Older Prevalent Newer
Small 40 50 10
Medium 20 50 30
Large 10 40 50
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28
II. GROSS WASTE QUANTITIES
A. Daily Waste Quantities
Data describing individual waste streams from each
process in a fictitious average food processing plant are reported
in Table II-l. The wasteloads noted are those prior to any
screening or other treatment. The loading per case is based on
equivalent cases of 24 - No. 303 cans for vegetables and 24 -
No. 2 1/2 cans for fruit. Results of a recent survey ' 'of a
tomato cannery in California are included as Table II-2 to
provide a further example of representative plant conditions.
The total waste quantities and wastewater volumes, both
ranges and averages, are included in Table II-l. However,
although the total quantity of waste generated in a canning
operation is an important parameter for determining gross pollu-
tional discharge, treatment methods and effects require an
intimate knowledge of wastes associated with each process within
the cannery.
The distribution of water used in the various processes
in a typical cannery is summarized below. This tabulation was
based on the operation of many different plants. Individual
plants will vary widely, of course.
Operation Gross Water Application %
Range Average
Raw Product Preparation 25-55 34
(including peeling)
Syrup and Brine 2-10 6
Steam and Sterilization 10-20 14
Cooling 6-60 35
Clean-up 5-25 8
Other 1-6 3
Additional study is certainly required to determine the
effect of changes in plant operations upon the wasteload generated.
This would involve the thorough evaluation of the alternates
available and the economic factors involved.
-------
29
TABLE II-1 DAILY WASTE QUANTITIES
Subprocesses
of Preva-
lent
Technology
Wasteload, Lb/Day for Average Size Plant
Producing 10.000 Cases/Day
Wastewater
Volume (mgd)
Washing
Belt Conveyor
Sorting, Pit-
ting, Slic-
ing, Etc.
Blanching and/
or Peeling
Exhausting of
Cans
Processing
Cooling of Cans
Plant Cleanup
Box Washing
TOTAL
AVERAGE
BOD
500 - 3
30 -
50 -
1,500 - 4
0 -
50 -
50 -
320 - 1
100 -
2,600 - 10
7,000
,000
100
600
,000
150
600
600
,200
250
,500
SS
500
100
150
1,000
0
50
50
300
150
2,300
8
- 4,000
200
700
- 4,000
150
450
300
- 1,500
400
- 11,700
,000
TDS
300
30
100
2,000
0
40
300
230
200
3,200
7
- 1,500
100
500
- 4,000
200
- 1,200
- 1,000
- 1,000
500
- 10,000
,500
.080
.010
.010
.060
0
.010
.060
.060
.020
.310
0
- .250
- .050
- .075
- .250
- .025
- .050
- .300
- .200
- .050
- 1.250
.750
Normal canning season and period of major waste discharge averages
3 months per year.
Pluming volumes and wasteloads are included with their associated
subprocesses.
1.
2.
3. Average waste at about 0.5 mgd.
-------
30
TABLE II-1 DAILY WASTE QUANTITIES
Subprocesses
of Newer
Technology
Wasteload, Lb/Day for Average Size Plant
Producing 10.000 Cases/Day
Wastewater
Volume (mgd)
High Pressure -
Low Volume
Wash sprays
following
Mechanical
Harvesting
Belt Conveyor
Mechanical Sort-
ing, Trimming,
Pitting, etc.
Blanching and/ 1
or Peeling
Exhausting of
Cans
Processing
Cooling of
Cans
Plant Cleanup
Box Washing
TOTAL 2
AVERAGE
BOD
500 - 3
20 -
50 -
,500 - 4
0 -
50 -
50 -
180 - 1
50 -
,400 - 10
6,500
,000
100
600
,000
100
500
600
,000
200
,100
ss
200
20
100
900
0
40
40
200
100
2,100
7
- 5,000
200
700
- 4,000
100
500
800
- 1,200
400
- 12,900
,500
TDS
300
30
80
2,000
0
40
200
150
200
3,000
6
- 1,500
60
- 400
- 4,000
140
- 200
- 1,300
- 800
- 500
- 8,900
,700
.060 -
.010 -
0 -
.060 -
0 -
.010 -
.040 -
.050 -
.020 -
.250 - 1
.650
.200
.030
.060
.250
.020
.050
.240
.100
.050
.000
-------
31
TABLE II - 2
DISTRIBUTION OF LOAD FROM TOMATO
PROCESSING WASTE STREAM
Proportion of Total Plant Load(%)
Product Cleaning Flow BOD SS
Wastewater from tomato lug box
dump tank and flume. 9.6 6.0 7.4
Wastewater from first spray rinse
on draper belt after tomato dump tank. 7.0 3.5 4.4
Wastewater from second and third spray
rinses following tomato dump tank 11.8 1.8 2.8
Subtotal 28.4 11.3 14.6
Lye Peeling and Rinse
Wastewater from flume transporting
tomatoes from sorting area to
lye peelers (lye drippings from
lye peeler elevator boot were
included in this waste). 0.9 - 2.5
Wastewater from overflow flume
following lye peeling (1st rinse). 4.3 12.2 18.2
Wastewater from elevator boot under
the tomato skin removal sleeves and
sprays (2nd rinse). 7.8 26.7 19.4
Wastewater from rinse and skin removal
flumes following skin removal
sleeves (3rd rinse). 12.2 5.2 5.5
Wastewater from flumes transporting
tomatoes from peeling area to
canning belts 17.2 10.4 4.9
Subtotal 42.4 54.5 50.5
Sorting and Can Packing
Wastewater from sorting and belts -
west half 1.9 0.6 0.5
Wastewater from sorting and belts -
east half 2.2 0.3 0.5
Subtotal 4.1 0.9 1.0
-------
32
Can Cooling
Wastewater from cooling hot
(processed) cans
Proportion of Total Plant Loan(%)
Flow BOD SS
15.5
3.0 3.4
Subtotal
15.5
3.0 3.4
TOTAL
90.4 69.7 69.5
-------
BOD
HbT
0.7
0.65
SS
0.8
0.75
TDS
HbT
0.75
0.67
Volume
(gal)
75
65
33
B. Wasteload Production Rates
Table 11*3 illustrates the varying wasteloads generated
by different fruits and vegetables. The variety of processes
employed by different canneries results in the ranges of waste-
loads .
A summary of average waste loads produced per case of
food processed follows:
Prevalent
Newer
C. Total Wasteload
The following estimates for total wasteload generated in
1963 were derived by using the average wasteload and volume
figures given in Section II A under "Prevalent Technology" and
assuming the subprocess mix as given in Section I D.
BOD SS TDS Volume
(million Ib) (million Ib) (million Ib) (billion gal)
370 425 395 36
D. Gross Wasteload Projection
The following wasteload projections are based on the
values provided by the FWPCA and on the trend for most prevalent
subprocesses. It is assumed that water requirements and waste
production per unit production will be reduced as greater recir-
culation and improved methods and equipment are adopted in the
future.
Year 1968 1969 1970 1971 1972 1977
BOD, million Ib 435 445 455 460 465 490
SS, million Ib 500 510 520 525 535 565
TDS, million Ib 465 475 485 490 495 525
Vol., billion gal 39 40 40.5 41 41.5 44
-------
34
E. Seasonal Variation
Canning plants are characterized by seasonal variations
with many operating only 2 or 3 months each year.(5) Most plants
process more than one type of product and may be confronted with
overlapping seasons during which production schedules are
increased. Certain products can be prepared immediately after
picking and stored for further processing throughout the year,
thus reducing peaks of both production and waste discharges.
-------
35
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-------
37
Tables II-4 and II-5 are summaries of the seasons
for canning and freezing the most common fruits and vegetables.
Major changes in these variations are not expected because these
seasons depend on weather conditions. However, a trend toward
preparatory processing and storage, with final processing being
spread over the remainder of the year, could develop for certain
products.
-------
38
TABLE II - 4
CANNING SEASON - FRUITS
NUMBER OF OPENING AND LENGTH OF SEASON, MO.
FRUIT
Apples
Apricots
Black
Blue
Cran
w Goose
M
ttJ
f6
w Logan
Rasp
Straw
Cherries
Figs
Grapes
Grapefruit
Lemons
Olives
Oranges
Peaches
Pears
Pineapple
Plums
Prunes
STATES PROCESSING
16
6
10
5
3
4
2
6
8
11
4
6
4
1
1
2
18
10
2
5
6
CLOSING MONTHS
Aug.
June
June
June
Sept.
May
June
July
April
May
May
Aug.
Nov.
All
Oct.
July
June
July
Jan.
July
All
- Jan.
- Sept.
- Oct.
- Oct.
- Jan.
- Aug.
- Aug.
- Aug.
- Oct.
- Aug.
- Nov.
- Nov.
- May
Year
- Feb.
- June
- Sept.
- Jan.
- Nov.
- Nov.
Year
RANGE
2-4
0.5-2
0.5-2
1-2
1
1-2
1.5
0.5-1
1-6
1-2
1.5-3
1-2
5-8
12
4
4.5-6
0.5-2
1-4
1-4
1-2
1-12
AVERAGE
4
1
1
1
1
1
1.5
1
1
1
2
1.5
6
12
4
5
1
2
2
1.5
1
-------
39
TABLE II - 5
CANNING SEASON - VEGETABLES
NUMBER OF
OPENING AND LENGTH OF SEASON, MO.
VEGETABLE
Pickles
Pimentos
Pumpkin
Rhubarb
Spinach
Sprouts
Squash
Succotash
Sweet Potato
Tomatoes
Artichokes
Asparagus
Lima Beans
Snap Beans
Beets
Corn
Carrots
Kraut
Okra
Peas
STATES PROCESSING
7
6
16
5
15
0
10
6
12
30
1
13
13
31
14
20
7
12
8
20
CLOSING MONTHS
All
Aug. -
Sept.-
May -
Feb. -
Oct. -
Aug. -
July -
Mar. -
Feb. -
Apr. -
July -
May -
June -
June -
Sept.-
All
May -
Apr. -
Year
Dec.
Nov.
June
Dec.
Nov.
Oct.
Feb.
Dec.
May
Oct.
Oct.
Oct.
May
Oct.
May
Year
Sept.
Oct.
RANGE
12
1.5-3
1-2
0.5-1
0.5-4
0.5-2
0.5-2
2-7
1.5-6
3
2-3
1-4
1-4
1-6
1-2
1-6
12
2-4
1-2
AVERAGE
12
2
1.5
1
2.5
1.5
1.5
4
2
3
2
2
2
3
1
2
12
3
2
-------
40
III. WASTE REDUCTION PRACTICES
A. Processing Practices
Table III-l is a list of alternative subprocesses for
each fundamental process where waste reductions can be, or have
been.achieved through process changes. The waste reduction
efficiencies are based on the subprocesses typical of older
technology levels. Only the subprocesses contributing the major
wasteloads and those providing significant reductions have been
listed.
B. Treatment Prac t ices
The treatment of cannery wastes can be divided into two
categories: (1) partial or complete treatment by the industry,
and (2) municipal treatment. Most canneries discharge into
municipal sewers with minimal preliminary treatment - usually
only vibrating screens to remove part of the suspended solids.
In a recent survey of 113 canneries, 68 percent screened their
wastes which were subsequently discharged to the municipal
sewer system, while only 13 percent used their own treatment
plants; 2 percent had no treatment; and 17 percent either were
no longer in operation or supplied no information. Of the 14
plants providing their own treatment, 3 used screens only; 6
used oxidation ponds after screening; 2, spray irrigation after
screening; 1, screening plus neutralization; 1, screening, sedi-
mentation, and ridge and furrow irrigation; and 1, screening,
sedimentation, neutralization,and nutrient addition followed by
aeration.
Segregation of high strength low volume waste streams
is one economically feasible approach to in-plant waste treatment.
A strong waste representing only 2-5 percent of the total plant
flow but containing 70-75 percent of the total organic load is
normally much more economical to treat efficiently than a large
volume of waste relatively low in BOD, SS, and TDS.
Numerous treatment schemes have been employed by the
industry and by municipalities; however, due to the seasonal and
complex nature of the cannery operation, reliable performance and
cost data are difficult to obtain. This study will consider
industrial treatment of both liquid and solid waste. Reference
is made to Plate 6 for an overall treatment and disposal
schematic (Waste Treatment Flow Chart). Table III-2 lists
approximate removal efficiencies.
1. Removal Efficiencies
Each unit operation and process is evaluated separately.
Wherever possible, applicable performance data is reported.
Overall treatment efficiencies for combination operations and
processes can be determined from individual performance data.
-------
41
TABLE III-l PROCESS POLLUTION REDUCTION
Waste Reduction Efficiency (%)
Fundamental Processes
and Subprocesses
Pre-Cleaning
In- Plant Wash/Rinse
Field Pre-Cleaning
Spray Washing
Recirculation
Sorting
Dry
Wet (Flotation)
Peeling
Mechanical
Hot Lye
Steam Scalding
Transport
Water (Flume)
Mechanical
Water w/Recirculation
Blanching
Steam
Hot Water
Can Cooling
Water
Water w/Recirculation
Product Waste Disposal
Floor Disposal
Bin Collection
Conveyors
Flumes & Floor Gutters
Wasteload
0
50 - 80
0
0
0-20
0
0
10 - 40
5-10
0
15 - 20
0
0-10
0
0
0
0
50 - 90
50 - 90
0
Water
Volume
0
50 - 60
25
50 - 80
40 - 60
0
0
10 - 30
5-10
0
90 - 100
50
30 - 60
0
0
75
0
50 - 90
50 - 90
0
-------
42
TABLE III-2
TREATMENT REMOVAL EFFICIENCY
Method
Screening
20-40 Mesh
Wet Oxidation
Sedimentation
Flotation
Chemical Precipitation
Chemical Oxidation
Activated Sludge
Trickling Filtration
Anaerobic Fermentation
Lagoon ing
Spray Irrigation
Sand Filtration
POLLUTION
Flow to
Surface
Water
0
-
0
0
0
-
0
0
0
0-50
50-100
50-100
REDUCTION
BOD to
Surface
Water
0-10
-
10-30
10-30
39-89
-
59-97
36-99
40-95
83-99
100
15-85
(7.)
SS
to Surface
Water
56-80
-
50-80
50-80
70-90
-
90-95
85-90
-
50-99
100
100
-------
43
a. Liquid Wastes: Table III-2 summarizes the efficiencies
of various treatment methods employed in 1963.
1) Screening: Screening is almost universally the
first treatment step employed in the canning industry. The operation
is usually carried out with stationary, rotary, or vibrating screens
having a 20-40 mesh size.
Gyrating, circular screens have been used to a limited
extent; meaningful statistical data is not yet available, but the
3-way vibration allows the use of finer screen cloths and removal of
more suspended matter.
Following is a summary of the performance of several
screens used in canneries.
Screen Type Mesh
Rotary 6-10
Vibrating 20-40
Vibrating
Rotary
Revolving
Vibrating
50
28
40
40
Loading
3.5 gal/
sq ft/min
32-70 gal/
sq ft/min
8000-12,000
gal/hr
200 gal/
sq ft/hr
975 gal/
sq ft/hr
Waste
Removal
Efficiency
pea
400-600 Ib
red beet, 56% SS
tomato 79.77, SS
pea
0.8 cu ft/
1000 gal
135 Ib/
sq ft/hr
Ref.
(8)
(8)
(9)
(10)
(ID
(12)
In a few instances other means of mechanical solids
separation have been tried, such as microstrainers and centrifuges.
Theoretically, these devices would achieve higher removal efficiencies,
and their wider use appears worthy of research investigation.
2) Grease Removal: Negligible quantities of grease are
normally present in cannery operations.
3) Sedimentation/Flotation: These two operations are
employed (usually separately) to remove solids which are either
readily settleable or floatable. Little definitive information is
available on the efficiency of either process although peach and
tomato wastes have been treated by flotation (*>) with loadings of
7000 gal/sq ft subjected to 8-10 in of mercury vacuum, yielding
suspended solids removals of 50-80 percent.
-------
44
4) Chemical Coagulation and Precipitation:
Chemical agents such as lime and iron salts have been used to
precipitate cannery wastes but are not widely utilized due to
variation in efficiency and high chemical costs. The following
tabulation shows results with several wastes and indicates
suspended solids removals up to 90 percent and BOD removals up
to 75 percent. Other studies(•"••*' indicate BOD removal as high
as 89 percent.
CHEMICAL TREATMENT OF CANNERY WASTES
Chemicals Reduction Efficiency
Waste Lime Alum
SS BOD
Tomato 8.3 86.5 39.0
4.0 1.0 ... ... 50.0
Red Beets 9.0 ... 90.0 43.0
10.0 ... 4.0 ... 59.0
10.0 ... 48.0
Corn 9.10 ... 9-12 ... 60.0
6.0 ... 3.25 ... 50-75
Carrots 5.0 ... 1.0 ... 75.0
8.0 ... 75.0
Peas 7.5 ... 3.25 ... 50-75
Wax Beans 6.0 2.5 ... 50-75
5) Chemical Oxidation: Relatively little has been
reported in the way of successful chemical oxidation. Generally,
the amount of chlorine required to oxidize the waste is excessive,
and BOD reduction data is presently unavailable.
6) Biological Treatment: Most cannery wastes contain
a fairly high percentage of dissolved and colloidal organic solids.
This should lead to successful application of biological processes
to cannery waste treatment; however, due to the cost factor, the
highly seasonal nature of the canning operation, and the lack of
many specific nutrients in the wastes, successful high rate bio-
logical stabilization has been rare. However, as shown in Table
III-3, lagooning has been successfuly employed.
Experimental trickling filters have been found to have
removal efficiencies of over 90 percent™) for cannery wastes.
It was necessary, however, to reduce the loadings to achieve this
high efficiency. Normal loadings for standard rate trickling
filters are 0.22 to 0.38 Ib BOD/cu yd/day, whereas the above
experiments used 0.04 Ib BOD/cu yd/day. Other experiments(10/
with trickling filters using higher loading rates (3.28 Ib BOD/
cu yd/day) achieved a removal efficiency of 42 percent as compared
to 60-80 percent normally expected from first-stage, high-rate
-------
45
filters using municipal sewage. These experiments indicate that
the use of trickling filters with cannery waste is not partic-
ularly effective.
Activated Sludge application has been limited to
pilot scale studies. Reported efficiencies^) range up to 97
percent; however, in most cases the operation was hampered by
necessarily low BOD loadings, nitrogen and phosphorous deficiencies,
and extended aeration periods.
Anaerobic fermentation has a fair amount of applica-
tion within anaerobic lagoons. A summary of the processes is
found in Table III-2'17). It is seen that detention periods range
from 4-6 hours to 37 days, with 10 days being a reasonable value.
Loadings vary between 0.0096 Ib BOD cu ft/day to 0.43 Ib BOD/cu ft/
day, while BOD removal efficiencies range between 40-95 percent.
Aerobic lagoons have been employed in those areas
where land was available at low cost and intermittent odors were not
a restricting problem. Most aerobic lagoon data is concerned more
with odor control than BOD removal. Aerobic lagoons have been
found to operate efficiently when low loading rates and long
detention periods (+ 100 days) were coupled with sodium nitrate
control(18). Reported efficiencies have been as high as 83-99
percent <19> W>
SODIUM NITRATE APPLICATION RATES FOR ODOR CONTROL
NaNOo Application
Type ot Waste per 1000 No. 2 Cases (Ib)
Beans, green or wax 20
Beans, lima 60
Beets 200
Carrots 200
Corn 200
Peas, early 200
Peas, late 150
Tomatoes 200
7) Sand Filtration: Sand filtration has seen . _.
application as a oolishing step following chemical precipitation^
and sedimentation^^2). Loading rates ranged from 69 gal/acre/min
with an associated BOD removal of 85 percent to 87,000 gal/acre/min
resulting in a BOD removal of 15 percent. In all cases, filter
clogging was a major problem.
8. Irrigation: Cannery wastes can also be disposed
of by spray irrigation. Suitable land acreage nearby is required.
It is a satisfactory method that usually can be employed if waste
is non-toxic to the vegetation. Its use is primarily limited by
the capacity of the spray field to absorb the wastewater. High
BOD reductions may be expected as the waste is biologically
decomposed within the soil. Some spray irrigation performances
are tabulated on the following page.
-------
46
SPRAY IRRIGATION PERFORMANCE
Pump
rate
Product (gpm)
Tomatoes 1000
550
Corn 350
Asparagus
and beans 253
Tomatoes,
corn, and
lima beans 430
Lima beans 430
Cherries 215
Total
Area
Sprayed
(acres)
5.63
6.4
2.28
0.9
9.18
6.64
2.24
Rate of
Applica-
tion
(gpm/acre )
178
86
153.5
282
43.8
65
06.5
Average
Application
(in/day)
2.96
0.70
3.35
3.5
0.375
0.375
3.61
Average Loading
(Ib BOD/ (Ib SS/
acre/day)
413
155
864
22.5
40.5
65
807
364
139
500
356
14.7
46
654
Use of ridge-and-furrow irrigation or absorption beds
is limited to soils of relatively high water-absorbing capacity.
Permanent pasture grasses are apparently able to handle a heavier
organic load than alfalfa. Crop cover will provide as much as
85-90 percent more soil absorption. One type of crop recommended'
consists of the following mixture:
Mammoth Clover -
Ladino-Alsac mixture -
Alta-fescue -
Redtop -
Orchard Grass -
19
25
25
19
12
This mixture is sown at a rate of 16 Ib per acre to produce as dense
a cover crop as possible at the time of wastewater application.
b. Solid Wastes Disposal: In most plants the solid
wastes are a liability to the canner. In urban areas the canner
must pay on a weight or volume basis to have the wastes removed
from the plant. In some operations almost half the raw tonnage
received at the cannery must eventually be handled as solid waste.
Because of the lack of economic and technical information concerning
by-product potential, the canner or hauler normally disposes of the
wastes by the least expensive method available. Often, however,
thought and ingenuity has lessened the costs of solid waste disposal
and created economical methods of using these wastes, as in the
preparation of charcoal briquets from fruit pits.
1) Landfill: The most widely used approach for
disposal of solid wastes is by landfill. To maintain a sanitary
environment, it is essential that strict control be enforced to
ensure against ground water pollution, fly breeding,and odor
nuisances.
-------
47
Of paramount importance is the requirement that an earthen cover
be placed over the solid waste within 24 hours. Costs, including
hauling, range from $1 to $3 per cu yd of waste. A second method
of land disposal involves spreading the waste material in a thin
layer over the land surface. It must then be worked into the soil
to prevent odor production and fly breeding. Use of this method
has been curtailed by the decreasing availability ot low cost land.
2) Composting: With proper preparation of screen-
ings and cuttings, including grinding, pH control and nutrient
additives, it is possible to compost cannery solid wastes efficiently.
Studies'23) (24)^n(j£cate that a mixture of two parts of fruit wastes
to one part absorbing material, and a moisture content of 65-70
percent, will yield a satisfactory end product.
3) Pressing and Drying: Pressing and drying of
citrus wastes have resulted in by-product recovery of citrus feed
and citrus syrup. The feed is used for animals, while the syrup
is used in cordials, brandies, and fortified wines.
4) Incineration: In a few instances, comparatively
dry waste solids have been incinerated. Although no actual data is
available on this application of incineration, municipal wastes
have been incinerated when the solids content exceeded 35 percent.
Partial pre-drying of solids by use of stack gases has been
considered to reduce the calculated ignition. Ignition usually
takes place at a temperature of 1400°F. Incineration would reduce
BOD by close to 100 percent. However, air pollution is a major
obstacle to large scale incineration of solid cannery wastes.
5) Wet Oxidation: Combustion via wet oxidation or
pressure burning has been used on industrial wastes as well as
municipal wastes. BOD removal efficiencies can approach 99 percent.
Acceptance of this process has been limited by the high costs.
6) Animal Feed: Disposal of wet waste solids by
feeding to animals has been widely practiced in some areas of the
country. However, there are many important objections: opposition
from residents near the intended site of operation; prohibitive
hauling costs; lack of balanced nutrients in fruit wastes; and
the seasonal nature of cannery operations. Tomato wastes have been
especially useful as animal feed, namely chicken and dog food,
7) City Sewers: From the canner's standpoint,
the most convenient method of solid waste disposal would be to
discharge to a sewage treatment plant. The obvious disadvantage
is the increased loading during the three-month canning season.
Appropriate increases would be required in the treatment works.
-------
48
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-------
2. Rates of Adoption
Since 1950, canning of fruits and vegetables has increased
at the relatively uniform rate of 2-1/4 percent per year.
Predictions made in 1957 based on the expansion of California
agriculture indicate an increase of at least 90 percent by the
year 2020. Since a large percentage of canned products originates
in California, this estimate should be fairly accurate for the
industry as a whole. This predicted expansion anticipates an
annual growth of approximately 1-1/2 percent per year. In 1967,
the Business and Defense Services Administration, U.S. Department
of Commerce, prepared projections of the expansion of this
industry. These indicate that there will be a relatively uniform
growth rate of about 4 percent per year for the next 10 years.
It is anticipated that the rate of adoption of pollution
reduction techniques will continue at a rate at least equalling
the industry growth rate and possibly exceeding it. The national
effort to reduce pollution will create standards for most water-
courses in the near future. The rigorous enforcement of these
standards will force most of those plants not now providing
adequate treatment to either connect to a municipal system or
construct efficient facilities.
Industry will continue to improve techniques of water reuse
and production line modification, and changeover will reflect
the increasing cost of labor, equipment process water, and waste-
water disposal and treatment. Emphasis will be on dry, semi-dry,
and re-cycled wet processes to the greatest extent possible.
Economic factors, however, largely dictate the adoption of
in-plant waste reduction techniques. Each plant management makes
decisions based upon its own unique situation, and generally it
requires a positive benefit in cost savings or community re-
lations to justify in-plant changes effecting waste reduction.
In past and present practice, the majority ot canneries
have discharged wastes to municipal sewers. Service charges
more often than not were based on hydraulic discharge, and pre-
treatment consisted only of screening. However, as water quality
standards increase and municipal treatment costs go up, there
will be greater incentive to shift to industrial treatment
utilizing methods specific to the industry's needs. Thus, new
canneries will be built to include as part of the normal
operation, waste conservation, treatment, and reclamation
facilities.
It is possible to list past treatment processes chrono-
logically, but such a survey is misleading because it does not
reflect changes in the state-of-the-art or increased sophistica-
tion. Instead, the survey would show that practical limitations
-------
50
rather than operational efficiency often dictated the choice
of treatment. Facilities were constructed which cost little
to build and less to operate. So long as the effluents were
acceptable to the community nothing further was required. However,
industry leaders recognize the need to upgrade environmental
quality,and various waste management systems are being evaluated
to develop cost and efficiency parameters.
While automation may lead to a greater emphasis on high
rate chemical and biological processes, this is not necessarily
the future trend. However, one may assume that modern research
and technology will be applied to all operations. Research,
development, and demonstration programs are most important to
prove the new technology needed for improved food process waste
management.
3. Discharge to Municipal Sewerage Systems
The quantity of wastes discharged from canneries to municipal
sewerage systems has been increasing in terms of both volume and
percentage. This trend is expected to continue for several
reasons: establishment and/or relocation of plants in developed
industrialized areas where municipal sewerage systems are avail-
able; urban growth encircling canneries with subsequent expansion
of municipal sewer systems; and increased pressure by regulatory
agencies regarding stream pollution. These assumptions are
reflected in the following estimate of the percentage of wastes
discharged to municipal sewers.
Year 1950 1963 1967 1972 1977 1982
Wastes Dis-
charged to 50 60 62 65 69 74
Sewers (7.)
Although cannery wastes are amenable to combined treatment
with municipal sewage, several problems are encountered in this
practice. First, most canneries operate seasonally as noted in
Section II E. The sudden and burdensome pollutant load on a
municipal treatment plant often reduces the efficiency of that
plant. Second, certain cannery processes, such as lye peeling
or blanching, produce a slug of hot and/or alkaline waste
sufficient to upset physical, chemical, and biological processes
at the municipal plant.
These difficulties may be reduced by ambitious water reuse;
proper pretreatment, such as adequate screening and equalization;
and efficient use of water in plant clean-ups. Proper sewer
service charges to discourage flagrant discharge of wastes may
improve combined treatment. In certain instances the charges are
based on peak instantaneous flow rates and maximum wasteload
as well as total volume discharged.
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51
C. By-Product Utilization
In the food processing industry, wastes are largely organic
and of a highly bio-degradable nature. However, in a few
instances, solid wastes have been sold in adjacent agricultural
communities. In particular, tomatoes have been pressed and de-
hydrated for use as hog or cattle feed. Pea vines, corn husks,
and corn cobs have also had limited sales. Citrus peel wastes
may be pressed for molasses which can be processed, dried ,and
sold as cattle feed. It has been reported that installation of
flash evaporators to produce the molasses has significantly
reduced the wasteload discharged. Certain types of pits and nut
shells are being converted to charcoal.
Due to the low value of these by-products, the primary
benefit to the cannery at this time is the avoidance of the cost
of hauling wastes to a landfill. As the cost of solid waste
disposal increases, it is anticipated that new by-products will
be developed,but projecting these by-products in terms ot waste-
loads and volumes would be conjecture.
D. Net Waste Quantities (1963)
The gross waste discharged in 1963 has previously been
estimated in Section II A 4 as 370 million Ib of BOD, 425
million Ib of SS and 395 million Ib of TDS. In 1963 it was
estimated that 60 percent of the cannery plant waste was dis-
charged to a municipal system and treated by municipal sewage
treatment facilities. Most of the waste discharged to a municipal
system was pretreated by in-plant screens or some other means of
gross solids separation prior to discharge.
Of that waste which is not discharged into municipal sewers,
it is estimated that virtually all is treated by some form of
gross solids separation prior to discharge; however, only one-
third is subjected to complete secondary treatment. This one-
third represents approximately 13 percent of the total waste
discharged.
Average pollution reduction efficiency for municipal plants
in 1963 is estimated as follows: BOD 75 percent, SS 85 percent,
and TDS 14 percent. These removal efficiencies include the pre-
treatment given at the food plant prior to discharge into the
sewer.
Average pollution reduction for industry owned and operated
secondary treatment facilities in 1963 is estimated as follows:
BOD - 80 percent, SS - 90 percent, and TDS - 30 percent. The
reason behind the higher reduction for industry operated plants
is the wide prevalence of spray irrigation and evaporation/perco-
lation ponds which essentially keep 100 percent of the organic
waste out of the nation's watercourses.
-------
52
Estimated net wastes reaching watercourses in 1963 are
noted in Table III-4.
E. Projected Net Wasteload
The net waste quantities are estimated in Table III-4.
These quantities were calculated based on the gross wasteload
generated by the canneries before any treatment within the
plant, the projected reduction efficiencies within the canneries
and municipal treatment facilities, and the projected percentage
of wastes discharged to municipal treatment works.
-------
53
1968
1969
1970
1971
1972
1977
TABLE III-4
PROJECTED NET WASTELOADS
Gross produced
by plants Removal
Waste (million Ib) (%)
BOD 370 57
SS 425 63
TDS 395 12
BOD 435 64
SS 500 73
TDS 465 19
BOD 445 65
SS 510 74
TDS 475 19
BOD 455 66
SS 520 75
TDS 485 19
BOD 460 67
SS 525 76
TDS 490 19
BOD 465 68
SS 535 77
TDS 495 19
BOD 490 73
SS 565 82
TDS 525 21
Net quantity
reaching
watercourses
(million Ib)
160
160
350
155
135
375
155
135
385
155
130
390
150
125
395
150
125
400
130
100
415
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54
IV. COST INFORMATION
A. Existing Facilities Costs
It is estimated that in 1966 virtually all of the
nation's canneries operated and maintained at least some form
of gross solids separation facility, such as screens, to pre-
treat the waste prior to discharge. An estimated 13 percent
of the plants provided further secondary type treatment such
as spray irrigation, percolation/evaporation ponds, etc. It
is estimated that the 1966 replacement value of these industry
owned and operated waste treatment facilities was about $18
million, and that the operating and maintenance costs were in
the order of $3 million. These estimates exclude the costs of
in-plant water conservation, reuse, and reclamation.
It must be noted that the above values are for industry
owned and operated waste effluent facilities only. It is
estimated that in 1960 approximately 62 percent of the waste was
discharged into and treated by municipal systems. Since industry
pays taxes and surcharges to support these facilities, the true
industry cost exceeds the foregoing amounts. The replacement
value of that portion of municipal treatment facilities construc-
tion attributable to this industry's waste is estimated to be
$60 million. On the same basis, the annual operating and main-
tenance cost is estimated at $10 million.
The total 1966 waste reduction costs (exclusive of
sewage collection system, costs such as municipal sewers) are
estimated to be:
Facilities replacement value - $78 million
Operation and maintenance cost - $13 million
B. Processing and Treatment Costs
This portion of the survey analyzes costs involved in
subprocesses and end of the line treatment. Tables IV-1 through
IV-9 break down costs for various sizes of plants and levels of
technology. Because of the wide ranges in the information feed:-
back from the industry, cost ranges have been used in the tables.
Table IV-10 gives estimated cost data on the entire industry and
relates cost of waste treatment to cost of production. We
believe this latter table gives a much more accurate picture of
the present industry cost situation than do the tables preceding
it.
New machinery for subprocesses is purchased by the industry
primarily on the basis ot increasing production efficiency and
product quality. The pollution load produced by the subprocess
has been a secondary consideration. However, canners and frozen
food processors are gradually becoming more aware of the problems
and costs associated with water use and wasteload discharge.
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55
The end of the line waste treatment may have little
relationship to the technology ot the process that created the
waste or the size of the plant; i.e., an older technology plant
may have an efficient waste treatment facility, and a modern,
efficient plant may have no waste treatment facility at all.
With few exceptions, the end of the line treatment is selected
primarily on the basis of requirements imposed by regulatory
agencies responsible for the watercourses being affected.
The following estimated costs are for plants incor-
porating pure states of technology; i.e., completely old,
completely prevalent, completely advanced. Few such plants
exist. Most are mixtures of varied subprocess technologies
since they have been modernized in stages over a relatively
long period of time.
The following definitions are necessary for proper
interpretation of the tables.
Ola technology - that technology new in 1950
Prevalent technology - that technology new in 1963
Newer technology - that technology new in 1967
Small plant - processing 2,000 cases per day
Medium plant - processing 10,000 cases per day
Large plant - processing 30,000 cases per day
Capital cost - equivalent 1966 cost
Annual operating and maintenance expenditures -
equivalent 1966 cost
Economic life - the length of time the machine or
structure can be expected to compete with advancing
technology, essentially the length of time before
economic obsolescence. This will vary greatly de-
pending upon the nature of the produce, dynamics
of industry growth, region, etc.
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56
TABLE IV-1 COSTS - SMALL PLANT (2000 cases/day)
OLD TECHNOLOGY (1950)
Item
Capital Annual Operating & Economic
Costs Maintenance Expenditures Life
($1000)
Subprocesses
Washing
Sorting , Slicing , etc .
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
10
10
10
10
30
10
50
130
- 20
- 20
- 30
- 30
- 60
- 20
-
- 80
- 260
($1000)
10
70
15
5
70
5
15
10
200
- 20
- 100
- 20
- 10
- 100
- 10
- 20
- 25
- 305
(Years)
7
7
7
7
7
7
-
10
End of Line
Treatment
Screening 1-5 0.3 - 0.8 10
Sedimentation 2-6 0.4-1 10
Flotation 3-8 0.5 - 1.3 10
Chemical Precipitation 3-9 1.3-5 10
Activated Sludge 11-30 1.8-5 10
Trickling Filters 9-20 1.3-3 10
Lagoons 1-3 0.1 - 0.3 10
Spray Irrigation 1-6 0.5-1.3 10
Solid Waste Disposal - 0.4 - 2.5
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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57
TABLE IV-2 COSTS - MEDIUM PLANT (10,000 cases/day)
OLD TECHNOLOGY (1950)
Item
Capital Annual Operating & Economic
Costs Maintenance Expenditures Life
($1000)
Subprocesses
Washing
Sorting .Slicing , etc .
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
50
50
60
40
150
40
300
690
- 70
- 100
- 120
- 80
- 250
- 80
-
- 400
-1100
($1000)
40
300
50
10
250
10
30
70
760
- 80
- 350
- 70
- 20
- 350
- 20
- 40
- 150
-1080
(Years)
6
6
6
6
6
6
6
13
End of Line
Treatment
Screening 4-20 1-2 10
Sedimentation 9-25 1.5-4 10
Flotation 11-30 2-5 10
Chemical Precipitation 11-35 5-20 10
Activated Sludge 45 - 120 7 - 20 10
Trickling Filters 35-80 5-12 10
Lagoons 3-10 0.5-1 10
Spray Irrigation 5-25 2-5 10
Solid Waste Disposal - 1.5-10
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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58
TABLE IV-3 COSTS - LARGE PLANT (30,000 cases/day)
OLD TECHNOLOGY (1950)
Capital
Item Costs
($1000)
Annual Operating & Economic
Maintenance Expenditures Life
($1000) (Years)
Subprocesses
Washing
Sorting,Slicing,etc.
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
End of Line
Treatment
Screening
Sedimentation
Flotation
Chemical Precipitation
Activated Sludge
Trickling Filters
Lagoons
Spray Irrigation
Solid Waste Disposal
Special Notes:
75
150
150
100
300
100
- 170
- 250
- 350
- 200
- 500
- 200
650 -1300
1525 -2970
100
600
110
30
550
30
100
200
- 200
- 800
- 160
- 50
- 650
- 50
- 150
- 400
5
5
5
5
5
5
15
1720 -2460
8.4
19
23
23
95
74
6.3
10.5
- 42
- 53
- 63
- 74
- 252
- 168
- 21
- 53
2
3,
4.
- 4.2
.2- 8.4
.2-10.5
10.5-42
15 -42
10.5-25
1-2
4.2-10.5
3.2-21
10
10
10
10
10
10
10
10
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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59
TABLE IV-4 COSTS-SMALL PLANT (2000 equivalent
cases/day) , PREVALENT TECHNOLOGY (1963)
Item
Capital
Costs
($1000)
Annual Operating &
Maintenance Expenditures
($1000)
Economic
Life
(Years)
Subprocesses
Washing
Sorting,Slicing,etc.
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
End of Line
Treatment
Screening
Sed imentation
Flotation
Chemical Precipitation
Activated Sludge
Trickling Filters
Lagoons
Spray Irrigation
Solid Waste Disposal
Special Notes:
10
10
15
15
35
15
80
180
25
25
35
35
70
30
100
320
10
65
15
5
65
5
15
10
190
20
90
20
10
90
10
20
20
- 280
6
6
6
6
6
6
12
0.8
1.7
2
2
8.5
6.6
0.6
1
- 3.8
- 4.7
- 5,7
- 6.6
- 23
- 15
- 2
- 4.7
0.2
0.3
0.4
1
1.3
1
0.1
9.4
0.3
0.4
0.8
1
3.8
3.8
2.3
0.2
1
2
10
10
10
10
10
10
10
10
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment cos.ts achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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60
TABLE IV-5 COSTS - MEDIUM PLANT (10,000 cases/day),
PREVALENT TECHNOLOGY (1963)
Capital
Item Costs
($1000)
Annual Operating & Economic
Maintenance Expenditures Life
($1000) (Years)
Subprocesses
Washing 60 90 40-80 5
Sorting,Slicing,etc. 60 - 120 275 - 325 5
Blanching and/or 80 - 160 40-60 5
Peeling
Exhausting of Cans 50 - 100 10-20 5
Processing 200 - 300 225 - 325 5
Cooling of Cans 60 - 120 10-20 5
Plant Clean-up - 30-40
Rest of Plant 475 - 575 70 - 150 10
Total
700 - 1020
End of Line
Treatment
Screening 3.2-16 0.8-1.6 10
Sedimentation 7.2- 20 1.2-3.2 10
Flotation 8.8-24 1.6-4 10
Chemical Precipitation 8.8-28 4-16 10
Activated Sludge 36-96 5.6-16 10
Trickling Filters 28-64 4-9.6 10
Lagoons 2.4 - 8 0.4 - 0.8 10
Spray Irrigation 4-20 1.6-4 10
Solid Waste Disposal - 1.2-8
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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61
TABLE IV-6 COSTS - MEDIUM PLANT (10,000 cases/day),
NEW TECHNOLOGY (1967)
Item
Capital
Costs
($1000)
Annual Operating &
Maintenance Expenditures
($1000)
Economic
Life
(Years)
Subprocesses
Washing
Sorting,Slicing,etc.
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
End of Line
Treatment
Screening
Sedimentation
Flotation
Chemical Precipitation
Activated Sludge
Trickling Filters
Lagoons
Spray Irrigation
Solid Waste Disposal
Special Notes:
100
190
190
130
400
130
220
320
450
260
650
260
1000 - 2000
2140 - 4360
100
500
110
30
550
30
100
200
200
700
160
50
650
50
150
400
4
4
4
4
4
4
15
1620 - 2360
8 -
19 -
23
23 -
95 -
74
6.3 -
10.5 -
42
53
63
74
252
168
21
53
.2
3.2
4.2
10.5
15
10.5
1
4.2
3.2
4.2
8.4
10.5
42
42
25
2
10.5
21
10
10
10
10
10
10
10
10
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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62
TABLE IV-7 COSTS - SMALL PLANT (2000 cases/day),
NEW TECHNOLOGY (1967)
Item
Capital
Costs
($1000)
Annual Operating & Economic
Maintenance Expenditures Life
($1000) (Years)
20
25
20
15
40
15
100
235
- 35
- 40
- 30
- 35
- 60
- 30
- 150
- 380
10
60
15
5
65
5
15
15
190
- 20
- 85
- 20
- 10
- 90
- 10
- 20
- 25
- 280
5
5
5
5
5
5
15
Subprocesses
Washing
Sorting,Slicing,etc.
Blanching and/or
Peeling
Exhausting of Cans
Processing
Cooling of Cans
Plant Clean-up
Rest of Plant
Total
End of Line
Treatment
Screening
Sedimentation
Flotation
Chemical Precipitation
Activated Sludge
Trickling Filters
Lagoons
Spray Irrigation
Solid Waste Disposal
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
0.6 -
1.3 -
1.6 -
1.6 -
7
5
0.4 -
0.7 -
3
4
5
5
18
12
1.5
4
0.2
0.2
0.3
0.8
1
1
0.1
0.2
0.2
- 0.3
- 0.6
- 0.8
- 3
- 3
- 2
- 0.2
- 1.5
- 1.5
10
10
10
10
10
10
10
10
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63
TABLE IV-8 COSTS - MEDIUM PLANT (10,000 cases/day),
NEW TECHNOLOGY (1967)
Item
Capital
Costs
($1000)
Annual Operating & Economic
Maintenance Expenditures Life
($1000) (Years)
Subprocesses
Washing 60-90 40-80 5
Sorting,Slicing,etc, IQO - 200 250 - 300 5
Blanching and/or 90 - 180 40-60 5
Peeling
Exhausting of Cans 50 - 100 10-20 5
Processing 220 - 320 210 - 290 5
Cooling of Cans 60 - 120 10-20 5
Plant Clean-up - 30-40
Rest of Plant 575 - 700 60 - 140 15
Total
1155 -1710
650 - 950
End of Line
Treatment
Screening 2.7-13 0.7-1.3 10
Sedimentation 6-17 1-2.7 10
Flotation 7.4 - 20 1.3 - 3.4 10
Chemical Precipitation 7.4-24 3.4 -13 15
Activated Sludge 30 - 81 4.7 -13 10
Trickling Filters 23-54 3.4-8 10
Lagoons 2-7 0.3-0.7 10
Spray Irrigation 3.4 - 17 1.3 - 3.4 10
Solid Waste Disposal - 1-6.7
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a-plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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64
TABLE IV-9 COSTS - LARGE PLANT (30,000 cases/day),
NEW TECHNOLOGY (1967)
Item
Capital Annual Operating & Economic
Costs Maintenance Expenditures Life
($1000)
($1000)
(Years)
75
400
110
30
500
30
90
200
1435
- 150
- 700
- 160
- 50
- 620
- 50
- 140
- 400
- 2270
4
4
4
4
4
4
Subprocesses
Washing 120 - 240
Sorting,Slicing,etc. 300 - 500
Blanching and/or 200 - 400
Peeling
Exhausting of Cans 140 - 270
Processing 400 - 700
Cooling of Cans 130 - 260
Plant Clean-up
Rest of Plant 1300 - 2800
Total 2S90 - 5170
End of Line
Treatment
Screening 6.3 - 32 1.6 - 3.2 10
Sedimentation 14-40 2.4-6.4 10
Flotation 17-48 3.2-8 10
Chemical Precipitation 17-55 8 - 32 10
Activated Sludge 71 - 190 11-32 10
Trickling Filters 55 - 127 8-19 10
Lagoons 4.7 - 16 0.8 - 1.6 10
Spray Irrigation 8-40 3.2-8 10
Solid Waste Disposal - 2.4 - 16
Special Notes:
1. All costs are equivalent 1966 costs. (To determine actual costs for
an earlier year, an appropriate conversion factor may be used).
2. Percentage of pollution reduction achieved by a particular end of the
line treatment process is simplified and assumed to be the same in
compared years. For example, it is assumed that the screening
process in 1950 would achieve the same efficiency of pollution
reduction as screening in 1963 and 1967.
3. The end of the line treatment does not include any sewer collection
system costs. It is assumed that the waste treatment facility is
located adjacent to the industrial waste source.
These assumptions were considered necessary to comply with the contract
while permitting comparison of waste treatment costs achieved first,
by lesser waste volume and strength generated by a plant per unit of
product and second, by increased efficiency in certain end of the line
waste treatment processes.
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65
TABLE IV-10
SUMMARY OF PRODUCTION AND WASTE TREATMENT COSTS
CANNED FRUITS AND VEGETABLES
Item
Total production
*
Total value added in manufacture
Average unit value added in manufacture
Estimated replacement value of waste
reduction facilities
**
Annual amortized cost of facilities at
77. and 10 yr life **
Estimated annual waste reduction
operating and maintenance cost **
Average industry cost of waste treatment
per unit of production
Total waste reduction costs as percent
of total production cost
Quantity
589 million equivalent cases
$1,030 million
$1.75 / equivalent case
$78 million
$11.5 million
$13 million
$0.041 / equivalent case
2.35 percent
* From the Business and Defense Services Administration,
U.S. Department of Commerce, 1967.
** Estimated replacement value, estimated amortization, and estimated
annual operating costs include an estimate of the cost of
municipal treatment facilities attributable to this industry's
wastes.
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66
Industrial Waste Profile
Frozen Fruits and Vegetables - SIC 2037
U. S. Department of the Interior
Federal Water Pollution Control Administration
I.W.P. No. 4 - Frozen Fruits and Vegetables
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67
INDUSTRIAL WASTE PROFILE STUDIES
SIC NO. 2037. FROZEN FRUIT AND VEGETABLE INDUSTRY
INTRODUCTION
There are approximately 1150 frozen food processing plants
in the United States. They produce almost all of the basic
frozen food items, both individually and in combinations. The
1966 food pack'2) included 664 million Ib of fruits and berries?,
77 million gal of juice concentrates (excluding lemon juice and
lemonade), and 3459 million Ib of vegetables. The 1966 retail
value of this pack approaches $3 billion^) .
For many years information concerning the frozen food industry
has been limited primarily to incidental data contained in the
canning industry literature. Because the cannery industry is
larger, older, and better organized than the frozen food industry,
the latter has received little comprehensive study. An effort
should be made to rectify this situation because of the unique
problems and rapid growth rate o± the frozen food industry.
Table I depicts this growth from 1950 to 1966 in terms of Ib
of product processed, number of cases packed, and retail value
of the finished product. To facilitate comparison, frozen food
product quantities have been converted to their equivalent in
terms of canned food cases containing 24 No. 303 cans.
Labor saving specialty foods, mixes, TV dinners and pre-cooked
decorative frozen foods are becoming increasingly popular for house-
hold and commercial consumption. Very little data is available
regarding pollution from these segments of the industry.
* Approximately 650 of these plants process fruits and
vegetables.
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68
TABLE I
FROZEN FOOD AND VEGETABLE PACK
Year
1950
1954
1963
19651
1966
Per
Million
wt, Ib
equiv. cases
of #303
retail
value $
wt, Ib
equiv.
cases of
#303
retail
value $
wt, Ib
equiv .
cases of
#303
retail
value $
wt, Ib
equiv .
cases of
#303
retail
value $
Frozen
Vegetables
587
372
N.A.
975
612
172
2322
145
396
3459
2162
N.A.
Frozen
Fruit
472
292
N.A.
523
332
260
620
39
436
664
422
N.A.
Frozen3
Juices
907
38
N.A.
2440
102
_ 4
18105
76
4
26205
97
N.A.
1. 1966 pack statistics except where the latest available
information was 1965.
2. At 0.0625 cases of #303 cans/lb (16 Ib/case based on 1.5
conversion factor from frozen weight to canned weight.
3. Reconstituted and based on a weight of 8.5 Ib/gal; exclusive
of berry purees.
4. Included in frozen fruit.
5. Exclusive of lemon and lemonade concentrate.
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69
INDUSTRIAL WASTE PROFILE STUDIES
FROZEN FRUITS AND VEGETABLES
SIC 2037
I. PROCESSES AND WASTES
A. Fundamental Industry Processes
Due to the diverse nature of products handled by this
industry, coupled with the 1150 plants producing a variety of
frozen foods, a multitude of process schemes could be described.
Each frozen food processing plant is probably unique in its in-
house process. However, for the purposes ot this report,
processes will be generalized into the following categories:
1. Preliminary Cleaning and Preparation
2. Freezing of Juices
3. Processing of Frozen Fruits
4. Processing of Frozen Vegetables
Meat and fish processing are not included in this study,
nor is the freezing of prepared foods and soups.
1. Preliminary Cleaning and Preparation
The preliminary cleaning and preparation required for raw
fruits and vegetables to be frozen is essentially the same as
that described for canning (Section I A 1, pages 10 - 13).
Howftver, these preliminary operations plus plant cleaning can use
up to 90 percent of the process water (exclusive of freezing system
water) used by the frozen food plant, and they normally contribute
the major portion of the pollution associated with the overall
process.
2. Juices - Frozen
In general, the methods employed in the preparation of
fruit juices for freezing differ little from those used in the
manufacture of fruit juices for flash pasteurization (see Section
I A3, pages 14 - 16).
The principal exception is that the juice is always
concentrated, and most of the water removed from the raw product
is discharged to waste. Since the vacuum evaporators are not 100
percent efficient, this waste has a fairly high organic pollution
loading.
3. Freezing of Fruits; In the freezing of fruits and
vegetables, the preliminary processes are very similar to those
of canning. The wastes produced are also quite similar. The
flavor and color of many varieties of fruit can be well preserved
by freezing, but a change in texture always occurs. A pronounced
characteristic flavor, attractive color, and good texture should
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70
be retained after defrosting. Most frequently, it is the texture
change which makes a variety unsuitable. Since soil and climate
affect fruits' characteristics for freezing, the area of the
United States in which it is grown will also affect its suit-
ability.
Quick Freezing Methods for fruits in the United States
began about 1929 on a commercial scale. Early methods used
immersion of the product in brine, or freezing of one side ot
the product only. Neither was satisfactory for frozen fruits.
In 1929, a Birdseye belt freezer was installed in the Ray-Maling
plant at Billsboro, Oregon. This process eliminated the danger
of spoilage due to bacteria, yeasts, and molds during freezing
of fruit and also resulted in a somewhat improved texture. On
the other hand, the quick freezing of a fruit packed in syrup
or with sugar immediately after packaging did not allow the sugar
to penetrate sufficiently into the fruit. For this reason, pro-
cessors have found it beneficial to hold fruits packed with sugar
or syrup at a temperature just above freezing for 1 - 2 hr prior
to quick freezing.
Although the untreated fruits in many instances are
greatly changed by freezing and thawing, comminuted fruits such
as pulped fruit and fruit juices may be preserved by freezing
for considerable periods of time without marked change either in
flavor or color. Pulping a fruit or converting it into juice
greatly reduces the exposure of the product to air, and thus
largely eliminates oxidation during freezing, storage, and thawing.
A similar effect may be obtained by freezing fruits under plain
sugar syrup or under syrup made by dissolving sugar in juice.
5. Freezing of Vegetables; Until 1928 it was believed
that freezing ruined vegetables since accidentally frozen vege-
tables spoiled almost immediately after thawing, and were un-
palatable when cooked. However, in 1929, both Joslyn and Cruess
concluded independently that it was necessary to blanch vegetables
before freezing. They recommended blanching with steam in pre-
ference to hot water. Blanching stops the enzymatic degradation
of vegetables which occurs after harvesting because of respiration,
reduces total bacteria count, and markedly retards the rate of
loss of vitamins A, Bj_, and C during storage.
Water blanching is often carried out in boiling water;
sometimes water as cool as 180°F is used. Hot sugar and acid
solutions have been recommended for blanching certain products
but are not commonly used. Steam is ordinarily used at atmospheric
pressure. The inactivation of the enzymes catalase and peroxidase
is the prime objective in blanching. In general, there is a
critical temperature range for each vegetable at which color,
flavor, and texture is most benefited by heating. The size of the
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71
vegetable is also a factor in determining the temperature and
length of time of blanching. For example, corn on the cob
requires a longer inactivation period than peas.
The general procedures recommended by Joslyn and Cruess
in 1929, before the advent of commercial freezing of vegetables,
were still used after 1957. The only difference is that after
1957 the blanched vegetables were packed in cartons without
covering with brine as suggested by Joslyn and Cruess. Vege-
tables are almost invariably prepared for cooking before being
frozen to preserve their crispness and valuable juices.
Most vegetables deteriorate very rapidly after harvest,
especially if allowed to stand in a warm place. Therefore, they
are normally prepared for freezing, or chilled at 40°F or lower,
immediately.
Furthermore, since warm vegetables lose flavor, vitamins,
and color very rapidly, they are normally cooled in very cold
running water directly after scalding.
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72
TABLE 1-1
TYPICAL EXAMPLES OF VEGETABLE FREEZING PROCESSES
Product
Processes
Artichokes
Asparagus
Baby Lima Beans
Beets (small)
Beets (large)
Broccoli
Corn (cut)
Blanched 7 rain in boiling 0.7 percent
citric acid
Cooled in water
Drained
Packed in moisture-proof packages
Stored in freezing chamber at -40°F for 4 hr
Steam blanched in a steam chamber about
30 ft long for about 3^ to 5 min
Cooled by water sprays
Packed in moisture-proof carton
Packed in either a multiple freezer or
on racks in a cold air blast at -20°F
Blanched in water at 212°F for 2% min
Cooled by a stream of cold water
Washed to remove brine
Packed in cartons
Frozen in an air blast at -10° to -15°F
Stored at 0°F
Steam blanched for 2% min in boiling water
Cooled in running water
Peeled in a mechanical peeler
Washed
Drained
Quick Frozen
Frozen after cooking
Steam blanched 3-5 min
Cooled in sprays or by immersion in water
in an endless chain
Packed in cartons
Frozen in air blast freezer on coils or on
plates
Steam blanched at atmospheric pressure
2-4 min
Cleaned and cooled by water to remove bits
of silk, husk, tiny particles of corn
Packed
Frozen in multiple freezer or trays placed
on racks
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73
TYPICAL EXAMPLES OF VEGETABLE FREEZING PROCESSES (Cont'd)
Product Processes
Peas Conventional hot water (most popular) or
steam (atmospheric blanching for 50-60
sec between 185°F and 205°F)
Some recirculation of hot water is practiced
Cooled in water flumes
Washed to remove salt
Packaged
TYPICAL EXAMPLES OF FRUIT FREEZING PROCESSES
Peaches Anti-oxidant fortified syrup added
after peeling and cooling
Packed in cartons
Held at a temperature just above
freezing for 1 or 2 hours to allow
syrup to penetrate fruit
Quick frozen
Strawberries Sugar syrup or dry sugar added
Packed in cartons or bags
Quick frozen
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74
B. Significant Pollutants
Significant pollutants in this industry arise from the
following operations:
1. Initial Preparation
2. Blanching
3. Hot Lye Peeling
4. Sorting, Slicing, Cutting, Blending, etc.
5. Processing
6. Washing (several washes are used in most plants)
7. Plant Clean-up
The combined wastes have the objectionable characteristics of high
BOD, IDS, and suspended solids. The initial preparation, blanching,
and peeling operations supply particularly concentrated wastes.
The effect of these pollutants on the receiving water is
similar to that of cannery wastes as described in Section I B,
pp. 16-17. However, the frozen food industry generally produces
a more dilute waste since the same amount of pollution is contained
in about twice the volume. In those cases where the waste is
discharged directly into the receiving stream, the initial dilution
would be of benefit.
C. Process Water Reuse - 1964
(3)
The following is a tabulationv of the 1963 water intake,
water use and reuse, and waste discharge for frozen fruit and
vegetable processing plants throughout the nation. It should be
noted this tabulation does not include plants using less than
20 MG/yr.
Water Quantity in Percentage of
Item billion gal/yr Intake Quantity
Water Intake 34 100
Process 15 44
Cooling, Con- 16 47
dens ing
Boiler Feed, 3 9
Sanitary Ser-
vice, & Other
Recirculated Water 15 44
Consumption 1 3
Discharge 33 97
Only 99 of the frozen food processing plants reported in the
1963 Census of Manufacturers. Based on other statistics from the
census, it was calculated that the industry's total water intake
and waste discharge were as follows:
Quantity in billion gal/yr
Intake Discharge
Frozen fruits and Vegetables 3b 35
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75
Comparing these water use statistics with those of the
canning industry shows that the frozen food industry uses almost
twice as much water per unit of production and that much of this
additional water is used in the cooling and condensing equipment.
In addition, less water is consumed in process, and a higher
percentage of the intake water is eventually discharged.
The industry estimates that in 1966 approximately 50 percent
of process water was reused at least once. In many instances
water from certain processes was reused many times.
D. Subprocess Trends
Table 1-2 describes the predominating subprocess mixes
for the frozen fruit and vegetable industry. Many plants do not
use all of the subprocesses shown and others use several methods
to accomplish one subprocess. Some of the subprocesses are
characteristic of only one segment of the industry. Totals for
any given subprocess may increase or decrease due to the change
in size of the segment of the industry using the given subprocess
relative to the rest of the industry.
These processes were studied by thoroughly reviewing
available literature, interviewing key personnel within the
industry, observing operations in several representative plants,
and analyzing production quantities given in the 1962,Almanac
of the Canning, Freezing, and Preserving Industries.
The tables consist of three sections as follows:
A) Initial Preparation
B) Frozen Fruits and Vegetables
C) Frozen Fruit Juices
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76
TABLE 1-2 SUBPROCESS TRENDS
Fundamental Process and
Subprocesses
SECTION A - INITIAL PREPARATION
Pre-Cleaning
1. Spray Wash, Rinse
2. Detergent Wash & Rinse
3. Water Soak Only
4. Water & Rinse Bath
5. Brine
6. Flume
7. Dry Cleaning
Sorting
1. Mechanical
a. Screening (size grading)
Percentage of Total Plants
1950 1963 1967 1972 1982
2.
b.
Hand
Flotation
Trimming
1. Hand
2. Silking & Husking
3. Mechanical
Coring & Pitting
1. Hand
2. Mechanical
3. Kernel Cutter
Cutting
1. Slicing
2. Dicing
3. Halving
4. Snipping
Peeling
1. Steam Scalding
2. Hot Lye
3. Abrasion
4. Mechanical Knives
10
10
95
35
5
15
10
20
5
25
25
15
20
10
10
5
20
15
85
30
5
15
5
25
5
25
25
15
20
5
15
5
70
5
0
5
5
10
5
20
20
85
25
5
20
5
25
5
25
25
15
20
5
15
5
70
10
0
0
5
10
5
25
25
75
20
5
25
3
27
5
25
25
15
20
5
15
5
35
25
70
15
5
30
2
28
5
25
25
15
20
5
15
5
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77
Fundamental Process and
Subprocesses
SECTION A (cont'd)
Grading & Inspection
1. Eye
2. Photo-Med. Color
Transport
1. Primary Flume (Water)
2. Conveyer Belt
3. Cart/Truck/Hand
Product Waste Disposal
1. Floor Disposal
2. In-process Bin Collection
3. Conveyors
4. Floor Gutters & Flumes
Plant Clean-up
Percentage of Total Plants
1950 1963 1967 1972 1982
100
"
45
75
10
10
30
20
100
100
60
80
8
5
20
10
100
98
2
65
85
6
2
13
10
100
95
5
70
90
3
1
9
20
100
85
15
70
95
2
5
30
100
100 100 100 100 100
SECTION B- FROZEN FRUITS & VEGETABLES
Blanching
1. Steam
2. Hot Water
3. Brine in Vac./Press.
Cooling
1. Running Rinse
2. Spray Rinse
Solid Waste Handling
1. Floor Disposal
2. In-process Bin Collection
3. Conveyors
4. Floor Gutters & Flumes
40 35
55 55
5 10
50
50
50
50
35
55
10
45
55
40 45
50 40
10 5
40
60
30
70
5
5
10
80
3
3
14
80
1
1
18
80
-
-
25
75
-
-
30
70
Plant Clean-up
100 100 100 100 100
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78
Fundamental Process and
Subprocesses
SECTION C - FROZEN FRUIT JUICES
Extraction
1. Crush/Press
2. Reaming
3. Pulping
Screening
1. Mesh Screen
2. Centrifuge
De-Oil
1. Heating in Vac.
De-Aerate
Clarification
1. Gelatin & Tannin
2. Pectic Enzyme
3. Flash Heating
4. Freezing & Thawing
Pasteurization
1. Pasteurization Only
2. Pasteurization & Concentration
Solid Waste Handling
1. Floor Disposal
2. In-process Bin Collection
3. Conveyors
4. Floor Gutters & Flumes
Percentage of Total Plants
1950 1963 1967 1972 1982
10
25
65
3
2
7
1
5
8
5
2
90
10
10
25
20
45
10
25
65
3
2
12
1
3
13
2
2
80
20
5
15
15
65
10
25
65
3
2
15
1
2
15
1
2
80
20
2
10
18
70
10
25
65
3
2
16
1
1
17
-
2
75
25
10
20
70
10
25
65
3
2
18
1
1
17
-
2
70
30
5
30
65
Plant Clean-up
100 100 100 100 100
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79
E. Waste Control Problems
The waste control problems in the frozen food industry are
similar to those in the canning industry (see Section I E p. 25).
F. Subprocess Technologies
The discussion of subprocess technologies found under canning
(see Section I Fpage 25) is also applicable to the frozen food
industry. The principal difference is the freezing step which does
not produce significant pollution.
There is an excellent discussion of relative plant sizes
found in "Organization and Competition in the Fruit and Vegetable
Industry", Technical Study No. 4, National Commission on Food
Marketing, June 1966. It reveals that the average plant output
in 1963 was 9.5 million pounds. It also shows that the Southeast
and Pacific regions have predominantly large plants; the Northeast,
small plants; and the Midwest, medium size plants. An arbitrary
classification of frozen food plant sizes is:
Small plant - annual output less than 8.5 million Ibs
Medium plant - annual output of 8.5 to 25 million Ibs
Large plant - annual output of over 25 million Ibs
The estimated percentage of plants falling into each classification
is:
Small - 50 percent, Medium - 25 percent, Large - 25 percent
The frozen food industry has experienced such phenomenal growth
in the last 15 years that any attempt to relate plant size to
technology level would be meaningless. It can safely be said that the
great majority of the plants would be classified as prevelant or
new in technology level.
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80
II. GROSS WASTE QUANTITIES
A. Daily Waste Quantities
Data describing individual waste streams from each
process in a fictitious average frozen food processing plant
are reported in Table II-l. It will be noted that the pollution
generated is slightly less than for an equivalent cannery
except for volume which is considerably higher.
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81
TABLE II-1 DAILY WASTE QUANTITIES
Subprocesses
of Preva-
lent
Technology
Wasteload, Lb/Day for Average Size Plant Wastewater
Producing 8.25 Tons/Day Volume (mgd)
Washing
Belt Conveyor
Sorting, Pit-
ting, Slic-
ing, etc.
Blanching and/
or Peeling
Plant Cleanup
TOTAL 2
AVERAGE
BOD
500 - 3
30 -
50 -
1500 - 4
320 - 1
,400 - 8
6,200
,000
100
600
,000
,200
,900
SS
500- 4
100-
150-
1,000- 4
300- 1
2,050- 10
6,200
,000
200
700
,000
,500
,400
TDS
300 - 1
30 -
100 -
2,000 - 4
230 - 1
2,660 - 7
5,000
,500
100
500
,000
,000
,100
.150
.020
.020
.150
.060
.400
1
- .500
- .100
- .150
-1.15
- .200
-2.10
,250
NOTES:
1. Normal season and period of major waste discharge averages
3 months per year.
2. Pluming volumes and wasteloads are included with their
associated subprocesses.
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82
TABLE II-1 DAILY WASTE QUANTITIES
Subprocesses
of Newer
Technology
Wasteload, Lb/Day for Average Size Plant
Producing 8.25 Tons/Day
Wastewater
Volume Ogd)
High Pressure-
Low Volume
Wash sprays
following
Mechanical
Harvesting
Belt Conveyor
Mechanical Sort-
ing, Trimming
Pitting, etc.
Blanching and/ 1
or Peeling
Plant Cleanup
TOTAL 2
AVERAGE
BOD
500 - 3,000
20 - 100
50 600
,500 - 4,000
180 - 1,000
,250 - 8,700
5,500
SS
200 - 5,000
20 - 200
100 - 700
900 - 4,000
200 - 1,200
1,920 -11,100
6,000
TDS
300 - 1,500
30 - 60
80 - 400
2,000 - 4,000
150 - 800
2,560 - 6,760
4,700
.130
.015
.010
.150
.050
.355
1
- .400
- .075
- .125
-1.00
- .100
1,700
,025
-------
BOD
(Ib)
0.62
0.55
SS
(Ib)
0.62
0.60
TDS
(Ib)
0.50
0.47
Volume
(gal)
125
102
83
B. Wasteload Production Rates
Table II-3 illustrates the varying wasteloads generated
by different fruits and vegetables. The variety of processes
employed by different plants results in the ranges of waste-
loads.
The following is a summary of average waste loads produced per
equivalent case processed.
Prevalent
Newer
C. Total Wasteload
The following estimates for total wasteload generated in
1963 were derived by using the average wasteload and volume figures
given in Section II A under "Prevalent Technology" and assuming the
subprocess mix as given in Section I D.
BOD S£ TDS Volume
(million Ib) (million Ib) (million Ib) (billion gal)
290 325 315 35
D. Gross Wasteload Projection
The following wasteload projections are based on the
values provided by the FWPCA and on the trend for most
prevalent subprocesses. It is assumed that water requirements and
waste production will be reduced as greater recirculation and
improved methods and equipment are adopted in the future.
Year 1968 1969 1970 1971 1972 1977
BOD million Ib 350 355 360 370 380 415
SS million Ib 390 400 410 420 425 470
TDS million Ib 380 385 395 495 415 455
Vol. billion gal 48 49 50 51 52 56
E. Seasonal Variation
See Section II E under canning.
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84
III. WASTE REDUCTION PRACTICES
A. Processing Practices
The discussion under canning (see Section III A, p. 40)
is also applicable to frozen food processing. Because frozen
food plants nationwide are generally in areas of cheaper water
supply and generally not connected to municipal sewers, there
has not been as much incentive to modify in-plant processes to
reduce pollution generated. Extensive study is required to
determine where and how process modifications can be made.
B. Treatment Practices
See discussion under canning (Section III B, p.40).
A higher percentage of frozen food plants have constructed their
own lagoons or spray irrigation disposal facilities because a
much lower percentage have access to municipal sewers.
1. Discharge to Municipal Sewerage Systems
The quantity of wastes discharged from the frozen
food industry to municipal sewerage systems has been increasing
in terms of both volume and percentage. This trend is expected
to continue for several reasons: establishment and/or relocation
of plants in developed industrialized areas where municipal
sewerage systems are available; urban growth encircling frozen
food processing plants with subsequent expansion of municipal
sewer systems; and increased pressure by regulatory agencies
regarding stream pollution. These assumptions are reflected in
the following estimate of the percentage of wastes discharged
to municipal sewers .
Year 1950 1963 1967 1972 1977 1982
Wastes Dis- 20 25 26 30 35 40
charged to
Sewers (%)
C. By-Product Utilization
In the food processing industry, wastes are largely
organic and of a highly bio-degradable nature. However, in a
few instances, solid wastes have been sold in adjacent agricul-
tural communities. Pea vines, corn husks, and corn cobs have
had limited sales for hog or cattle feed. Citrus peel wastes
may be pressed for molasses which can be processed, dried,and
sold as cattle feed. It has been reported that installation of
flash evaporators to produce the molasses has significantly
reduced the wasteload discharged.
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85
Due to the low value of these by-products, the primary
benefit to the plant at this time is the avoidance of the cost
of hauling wastes to a landfill. As the cost of solid waste
disposal increases, it is anticipated that new by-products will
be developed, but projecting these by-products in terms of
wasteloads and volumes would be conjecture.
D. Net Waste Quantities (1963)
The gross waste discharged in 1963 has previously been
estimated in Section II A 4 as 290 million Ib of BOD, 325
million Ib of SS and 315 million Ib of TDS. In 1963 it was
estimated that 25 percent of the frozen food plant waste was
discharged to a municipal system and treated by municipal sewage
treatment facilities. Most of the waste discharged to municipal
systems was pretreated by in-plant screens or some other means
of gross solids separation prior to discharge.
Of that waste which is not discharged into municipal sewers,
it is estimated that virtually all is treated by some form of
gross solids separation prior to discharge; however, only one-
third is subjected to complete secondary treatment. This one-
third represents approximately 25 percent of the total waste
discharged.
Average pollution reduction efficiency for municipal plants
in 1963 is estimated as follows: BOD 75 percent, SS 85 percent,
and TDS 14 percent. These removal efficiencies include the pre-
treatment given at the food plant prior to discharge into the
sewer.
Average pollution reduction for industry owned and operated
secondary treatment facilities in 1963 is estimated as follows:
BOD - 80 percent, SS - 90 percent, and TDS - 30 percent. The
reason behind the higher reduction for industry operated plants
is the wide prevalence of spray irrigation and evaporation/
percolation ponds which essentially keep 100 percent ot the
organic waste out of the nation's watercourses.
B. Projected Net Wasteload
The net waste quantities are estimated in Table II1-1.
These quantities were calculated based on the gross wasteload genera-
ted by the plants before any treatment within the plant, the
projected reduction efficiencies within the plants, and municipal
treatment facilities, and the projected percentage of waste dis-
charged to municipal treatment works.
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86
TABLE III-l
PROJECTED NET WASTELOADS
1968
1969
1970
1971
1972
1977
Waste
BOD
SS
TDS
BOD
SS
TDS
BOD
SS
TDS
BOD
SS
TDS
BOD
SS
TDS
BOD
SS
TDS
BOD
SS
TDS
Gross produced
by plants
_ (million Ib)
290
325
315
350
390
380
355
400
385
360
410
395
370
420
405
380
425
415
415
470
455
Removal
39
44
11
42
47
13
43
48
13
44
49
14
46
51
14
47
52
15
55
61
17
Net quantity
reaching
watercourses
(million Ib)
177
182
280
206
207
331
202
208
335
202
209
340
200
206
348
200
204
353
137
183
378
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87
IV. COST INFORMATION
A. Existing Facilities Costs
It is estimated that in 1966 about half of the nation's
frozen food processing plants operated and maintained at least
some form of gross solids separation facility, such as screens,
to pre-treat the waste prior to discharge. An estimated 25
percent of the plants provided further secondary type treatment
such as spray irrigation, percolation/evaporation ponds, etc.
It is estimated that the 1966 replacement value of industry
owned and operated waste treatment facilities was about $5 million,
and that the operating and maintenance costs were in the order
of $1 million. These estimates exclude the costs of in-plant
water conservation, reuse,and reclamation.
It must be noted that the above values are for industry
owned and operated waste effluent facilities only. It is
estimated that in 1960 approximately 24 percent of the waste
was discharged into and treated by municipal systems. Since
industry pays taxes and surcharges to support these facilities,
the true industry cost exceeds the foregoing amounts. The re-
placement value of that portion of municipal treatment facilities
construction attributable to this industry's waste is estimated
to be $20 million. On the same basis, the annual operating and
maintenance cost is estimated at $4 million.
The total 1966 waste reduction costs (exclusive of sewage
collection system costs such as municipal sewers) are estimated
to be:
Facilities replacement value - $25 million
Operation and Maintenance cost - $5 million
B. Processing and Treatment Costs
It is estimated that processing and treatment costs within
the frozen food industry lie within the ranges shown for the
canning industry in Section IV B pp. 54-65. It has been found
that the processing costs in the frozen food industry are very
close to those in the canning industry per equivalent unit of
production.
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88
TABLE IV-1
SUMMARY OF PRODUCTION AND WASTE TREATMENT COSTS
Frozen Fruits and Vegetables
Item
Total production
Total value added in manufacture*
Average unit value added in manufacture
Estimated replacement value of waste
reduction facilities **
Annual amortized cost of facilities at
7% and 10 yr life **
Estimated annual waste reduction
operating and maintenance cost **
Average industry cost of waste treatment
per unit of production
Total waste reduction costs as percent
of total production cost
Quantity
6.75 billion Ib
$538 million
$0.08/ Ib
$25 million
$3.5 million
$5 million
$0.001/lb
1.5 percent
* From the Business and Defense Services Administration,
U.S. Department of Commerce, 1967.
** Estimated replacement value, estimated amortization, and estimated
annual operating costs include an estimate of the cost of
municipal treatment facilities attributable to this industry's
wastes.
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-------
95
SPECIFIC BIBLIOGRAPHY
1. Almanac of the Canning, Freezing and Preserving Industries,
Compiled and Published by Edward S. Judge and Son,
79 Bond Street, Westminister,Md., 21157 (1967).
2. Frozen Food Pack Statistics. 1960, National Association of
Frozen Food Packers, Wash. D. C., 1967.
3. "Water Use in Manufacturing", U. S. Census of Manufacturing,
1964.
4. Water Resources Engineers, Inc. "Evaluation of the Technical
and Economic Feasibility of In-Plant Separation and/or
Treatment of Cannery Waste Flows", March 1966,
Prepared for the California Water Quality Control Board.
5. "The Canning Industry", National Canners Association
Publication (1963).
6. Anon., "Fruit Processing Industry-An Industrial Waste Guide",
U. S. Department of Health, Education and Welfare,
Public Health Service Pub. 952, Washington, D. C. (1962).
7. Burbank, N. C. Jr. and T. S. Kumagai, "A Study of a
Pineapple Cannery Waste ". Proceedings of the 20th
Purdue Industrial Waste Conference. 118, 365 (1966).
8. Sanborn, N. H., "Treatment of Vegetable Cannery Wastes",
Industrial and Engineering Chemistry. 34, 911
(August 1942); Sewage and Industrial Wastes, 14, 6,1366
(November 1942); 15^ 1, 155 (January 1943).
9. Anon., "Vibrating Screen Solves Pollution Problem",
Canner, 118, 24,23 (1954).
10. Eldridge, E. F., "The Treatment of Red Beet, Tomato, and
Squash Cannery Wastes", Bulletin 83, Michigan State
College Engineering Experiment Station, p. 15, (1939)
Sewage and Industrial Wastes, 10, 5, 914 (September 1938);
iwage
. 4,
11, 4, 712 (July 1939)
11. Kimberly, A. E., "Status of Pea-Canning Waste Treatment",
Water Works and Sewerage, 3, 553 (1931).
12. Hert, 0. H., "Tomato Canning Plant Wastes", Food Packer,
28, 10, 40 (October 1947).
13. Anon., "Experiments on Treatment of Cannery Waste", Sewage
Works Journal. 11, 339 (1939 Public Works. 70, 10 (1939).
14. Dickinson, D., "Performance of Recirculating Plant for
Purification in Biological Filters", Sewage and
Industrial Wastes. 21, 7, 757 (July 1949).
-------
96
15. "Trickling Filter Treatment of Liquid Fruit Canning Waste".
Washington, D. C. National Canners Association, 1967.
16. Water Resource Engineers, Inc. , "In-Plant Treatment of
Cannery Waste-A Guide for Cannery Waste Treatment,
Utilization and Disposal" (1967).
17. Agardy, F. J. and R. G. Spicher, "Anaerobic Treatment of
Cannery Wastes - A Bench Scale Study", C. W. P. C. A.
Meeting (1967).
18. Rudolfs, W., Industrial Waste Treatment, Reinhold 1953.
19. Jones, F. 0., "A Storage Lagoon for Wastes from Canning
Company Plants", Public Works, 75, 4, 21 (1944).
20. Davis, N. E. , "Control of Canning Waste Oxidation Ponds",
Public Works, 90, 8, 133 (1959), Water Pollution
Abstracts, 33, 102 (1960).
21. Bldridge, B. F., "Symposium on Industrial Wastes--
Canning Industry", Industrial and Engineering
Chemistry, 39, 5, 619 (May 1947).
22. Siebert, C. L. and C. Allison, "Some Rights and Wrongs
of Cannery Waste Treatment", Water and Sewage
Works, 95, 227 (June 1948). "*"*~"
23. Mercer, W. A., et al, "Aerobic Composing of Vegetable
and Fruit Wastes", Compost Science, 3,3,9 (Autumn 1963).
24. Rose, W. W., et al. "Composting Fruit and Vegetable Refuse",
Compost Science. 6, 2,13 (1965).
-------
97
APPENDIX I.
GLOSSARY
Definitions
Activated Sludge - a process for treating liquid waste by
aeration and recirculation of biologically active
sludge.
Aeration - the act of supplying with oxygen.
Aerobic - living or active in the presence of oxygen.
Anaerboic - living or active in the absence of oxygen.
Bio-degradation - reduction to a lower form by means of
living organisms.
Carbohydrase - an enzyme which hydrolyzes carbohydrates.
Blanch - to whiten by removing the skin, as by scalding.
Blow-down - process water removed from a recirculating system.
Brine - a strong activity solution of common salt, NaCl.
Catalase - an enzyme that catalyzes the decomposition of
hydrogen peroxide into water and oxygen.
Causticizing - treating with a corrosive chemical capable of
eating or destroying.
Countercurrent - flow of wash water in opposition to flow of
product so that the product encounters increasingly
cleaner water.
Coagulation - the change from a liquid to a thickened,
curd-like state.
Cull - an article rejected for inferiority or worthlessness.
Effluent - polluted water discharged from a process.
Enzyme - any of a class of complex organic substances that
accelerate specific transformations of material, as
the digestion of foods.
Equalization - the process of combining two or more
dissimilar wastes to produce a uniform composite.
-------
98
Fermentation - the catalytic decomposition of a complex
compound into simpler ones.
Glutamate - a salt or ester of glutamac acid (C5HgN04).
Lagooning - a. liquid waste treatment process of holding the
waste in shallow ponds for a period of several hours
to allow absorption of oxygen.
Leach - to subject to the action of percolating water or
other liquid in order to separate soluble components.
Lime - a caustic white solid, CaO, which forms slaked
lime, CO(OH)2 when combined with water.
Lye - any strong alkaline solution, especially potassium
carbonate.
Make-up - water used to supplement process water due to
system losses.
Neutralize - to adjust the pH of a solution to seven
(neutral) by the addition of an acid or a base.
Pectic acid - any of various water insoluble substances
formed by hydrolyzing the methyl ester groups of pectins.
Pectin - any of certain water-soluble substances in plant
tissues, yielding jelly which is the basis of fruit
jellies.
Peroxidase - an enzyme that catalyzes the oxidation of
various substances by peroxides.
Potable - drinkable.
Precipitate - to cause to separate from solution or
suspension.
Process - a series of actions or operations definitely
conducting to an end; continuous operation or treatment,
especially as in manufacture.
Proteinase - an enzyme which hydrolyzes proteins.
Raw Ton - one ton of unprocessed material.
Screening - separation of solid material from liquid waste
by passing the waste through screens.
Sedimentation - the act or process of settling matter to the
bottom of a liquid.
-------
99
Sludge - the precipitated solid matter produced by water and
sewage treatment process.
Subprocess - an alternate method of conducting a process.
Trickling Filtration - a liquid waste treatment process
involving trickling the waste through a bed of stone or
other inert material.
-------
100
Conversion Factors
Can Sizes
1 No. 10 can equals 7 No. 303 (1 Ib) cans
1 No. 10 can equals 5 No. 2 (1 Ib 4 oz) cans
1 No. 10 can equals 4 No. 2 1/2 (1 Ib 13 oz) cans
1 No. 10 can equals 2 No. 3 cylinder (46-50 oz) cans
A standard case consists of 24 - No. 303 cans at 1 Ib each, a
total of 24 Ib.
1 Ib of frozen fruits or vegetables is equivalent to
approximately 1.50 Ib of canned fruits or vegetables.
-------
101
APPENDIX II
GENERAL BIBLIOGRAPHY
Anon., "Canned Food Pack Statistics". Washington, D. C., National
Canners Association, 1966.
Anon., "Canners Director". Washington, D. C., National Canners
Association, 1965-66 Ed.
Anon., "The Canning Industry". Washington, D. C., National Canners
Association Publication, 1963.
Anon., "Conversion Factors and Weights and Measures for Agricultural
Commodities and Their Products". Bulletin 362, Washington,
D.C., U.S. Department of Agriculture, 1965.
Anon., "Frozen Food Pack Statistics 1966". Washington, D. C.,
National Association of Frozen Food Packers.
Anon., "How to Handle High BOD Fruit-Processing Wastes". Wastes Eng.,
34, 128 (1963).
Anon., "Information Letter". Washington, D. C., National Canners
Association, No. 2034, p. 235 (August 28, 1965).
Anon., "Physical and Chemical Characterization of the Freshwater
Intake, Separate In-Plant Waste Streams, and Composite Waste
Flow Originating in a Cannery Processing Peaches and Tomatoes".
Washington, D. C., National Canners Association.
Anon., "Spray Irrigation System Prevents Treat or Stop Operating
Order". Wastes Eng., 33, 3, 139 (Mar. 1962).
Anon., "Tests Performed in Conjunction with Canners Research Project".
Report from City of Stockton Main Water Pollution Control
Laboratory (Oct. 1964).
Anon., "Vibrating Screen Solves Pollution Problem". Canner, 118, 24,
23 (1954).
Anon., "When to Treat-or Not to Treat-Industrial Wastes with Sewage".
Wastes Eng.. 34, 22 (1963).
Anon., "1966 Canners Statistical Handbook". Division of Statistics
and Economics, Washington, D. C. 20036, National Canners
Association.
Bell, J. W., "Spray Irrigation and Research of Canning Plant Wastes".
Canadian Food Ind.. 32, 9, 31 (1961); Water Poll. Aba.. 35, 132
(1962).
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102
Besselievre, E. B./'Industrial Waste Treatment", McGraw-Hill, (1952).
Bo Iton, P., "Disposal of Canning Plant Wastes by Irrigation". Proc.
3rd Ind. Waste Conf.. Purdue Univ., Ext. Ser. 6A, 272 (1947).
Bonem, F. L., "Solve Seasonal Waste Disposal Problem". Food Proc.,
23, 2, 34 (Feb. 1962).
Bradakis, H. L., "A Joint Municipal - Industry Spray Irrigation
Project". Ind. Water and Wastes. 6, 4, 117 (July-Aug. 1961).
Burbank, N. C., Jr. and T. S. Kumagai, "A Study of a Pineapple Cannery
Waste". Proc. 20th Purdue Ind. Waste Conf.. 118, 365 (1966).
Burch, J. E., Lipinsky, E. S., and Litchfield, J. H., "Technical and
Economic Factors in the Utilization of Waste Products". Food
Tech.. 17, 1266 (1963).
California Water Pollution Control Board, "A Survey of Direct
Utilization of Waste Waters". Publ. No. 12. Sacramento, Calif.
(1955).
Canham, R. A., "Some Problems Encountered in Spray Irrigation of
Canning Plant Waste". Proc. Tenth Ind. Waste Conf.. Purdue
Univ., Ext. Ser. 89, 120 (1955).
Cessna, J. 0., "Modesto's Pollution Explosion". Water Works and
Wastes Eng.. 1, 2, 50 (1964).
Czirfusz, M., "Food Industrial Waste Water Purification by Hydro-
cyclone". Chetn. Abs. 58, 2264 (1963).
Dickson, G., "A Multipond Flow-Through Lagoon System for Treatment
of Cannery Wastes". Proc. 12th Pacific Northwest Ind. Waste
Conf., Univ. of Washington (1965).
Dougherty, M. H., "Activated Sludge Treatment of Citrus Wastes".
Journal of the Water Pollution Control Federation, 36, 1, 72
(Jan. 1964).
Dunstan, G. H., and Smith, L. L., "Experimental Operation of Industrial
Waste Stabilization Ponds". Public Works 91, 4, 93 (1960).
Eckenfelder, W. W., Jr., Lawler, J. P., and Walsh, J. T., "Study of
Fruit and Vegetable Processing Waste Disposal Methods in the
Eastern Region". Progress and Final Reports, U. S. Department
of Agriculture (Mar. 1957 and Sept. 1958).
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103
Eldridge, E. F., "The Treatment of Red Beet, Tomato, and Squash
Cannery Wastes". Bulletin 83, Michigan State College Engineer-
ing Experiment Station, p. 15, (1939) Sewage and Industrial
Wastes, 10, 5, 914 ^September 1938); 11, 4, 712 (July 1939).
Evans, R., "Industrial Wastes and Water Supplies". Jour. Amer.
Water Works Assn.. 57, 625 (1965).
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U S COVERNMLNT PRINTING OFFICL lQh8 O - 287-02!)
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