United States
Environmental Protection
Agency
Health Effects
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA-600/S1-84-029 Jan. 1985
&EPA Project Sumary
The Health Effect Potential of
Reusing Fruit Processing
Wastewater: The Health Effect
Potential of Reusing Treated
Fruit Processing Wastewater
Within a Cannery
Larry A. Esvelt and Herbert H. Hart
Presented in the full report are the
results of the second of two studies
conducted on the reclamation and
reuse of fruit processing Wastewater
from a fruit cannery in Yakima, WA.
This study, conducted from 1980 to
1982, focused on the presence of
potentially hazardous constituents in
wastewater reclaimed from fruit pro-
cessing and on whether these constitu-
ents pose any threat to human health.
During this 3-year health effects
potential study, biologically treated
(activated sludge) processing waste-
water was reclaimed using granular
media filtration and was disinfected by
chlorination. The reclaimed wastewater,
containing no sanitary wastes, was
then reapplied for critical uses in fruit
processing.
Constituents of concern in the waste-
water included heavy metals, pesticide
residues, polychlorinated biphenyls,
and volatile halogenated organics.
Analysis for these constituents was
completed by outside laboratories, and
all were found to be present at safe
levels. The chemical quality of the
wastewater was monitored at the
cannery by recording water tempera-
ture and obtaining turbidity readings.
The microbiological quality of the
wastewater was monitored daily by
plate tests for total coliform organisms
and total aerobic bacteria. Additional,
less frequent monitoring evaluated the
reclaimed wastewater for the presence
of yeast and mold organisms, anaerobic
bacteria, and mesophilic spores.
Project results indicate that fruit
processing wastewater that has received
good biological treatment, filtration,
and disinfection is suitable for critical
uses in a fruit cannery- The investigators
recommend that reclamation and reuse
of adequately treated processing waste-
water be approved for all high-acid food
processing plants. Data were not
available to determine whether such
water would be reusable in a low-acid
food to processing plant.
This Project Summary was developed
by EPA's Health Effects Research
Laboratory, Research Triangle Park.
NC, to announce key findings of the
research project that is fully documented
in a separate report of the same title (see
Project Report ordering information ata
back).
Introduction
The fruit and vegetable processing
industry uses about 110 billion gallons of
water annually and subsequently dis-
charges almost all of it as wastewater.
The increasing cost of suitable water and
its decreasing availability make waste-
water reclamation and reuse an inviting
alternative for supplementing primary
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water supply sources. Since the degree of
treatment already required for effluents
disposed of to surface waters (~ 28% of
all wastewater) is the highest, these
effluents are the most likely candidates
for reclamation and reuse by the fruit
processing industry.
This study was undertaken to assess
the health effects implications of the
reuse of reclaimed processing waste-
water in a fruit cannery. The project was
specifically designed to determine the
level of constituents in reclaimed water
that might be of significance to human
health if the water were used on a
continuous basis for critical processing.
The fruit cannery at which this study
took place is operated by Snokist Growers
in Yakima, WA. The cannery processes
over 2000 metric tons of fruit per year,
with pears and apples being the principal
fruits processed In 1967 the cannery
constructed an aerated lagoon treatment
facility, which it upgraded to an activated
sludge treatment system in 1968. This
system worked so we 11 between 1968 and
1973 that Snokist was awarded a U.S.
Environmental Protection Agency (EPA)
grant in 1974 to investigate the feasibility
of reclaiming wastewater treated by the
system for reuse in critical areas of fruit
processing. Effluent polishing and disin-
fection facilities were constructed in
1975 to enable the cannery to reclaim
water for reuse.
Based on the results of this first study,
Snokist investigators recommended that
a followup study of the health effects
potential of reusing treated wastewater
be conducted. Thus, the present study,
through a partial grant from EPA, was
initiated in 1980.
Procedure
Wastewater Treatment and
Reclamation Procedures
During biological treatment, nutrient-
deficient, high-carbohydrate fruit proces-
sing wastewater was screened in Snokist's
activated sludge treatment facility.
Nitrogen and phosphorus nutrients were
then added to allow proper biological
growth, and the wastewater was con-
veyed to an aeration basin. Remaining in
the basin 3-5 days, the wastewater was
mixed with return sludge and aerated by
low-speed surface aerators to oxidize the
soluble organics. The aeration basin
aerators were operated to maintain a
dissolved oxygen concentration of 2
mg/l. The sludge recycle rate for the
activated sludge system normally aver-
aged 1.5 to 2 times the wastewater flow
rate. From the aeration basin the waste-
water flowed to a clarifier, where settling
removed suspended solids. Solids re-
moved in the clarifier (activated sludge)
were either returned to the aeration basin
or wasted.
For purposes of this study, a portion of
the treated wastewater containing no
sanitary sewage was reclaimed during
three fruit processing seasonings for
reuse within the cannery. Fruits pro-
cessed during reuse of the reclaimed
wastewater were pears, apples, peaches,
and plums.
Reclamation procedures included
granular media filtration, chlorination,
retention for chlorine contact, and
pumping to a separate water distribution
piping system inside the cannery. A pump
fed the granular media filters by pressure,
and chlorine was administered propor-
tional to flow at a ratio automatically
adjusted to meet a preset residual.
Disinfection was enhanced by injection of
the chlorine solution from the gas
chlorinator into the discharge pipe from
the filters. After a short plug-flow contact
in the pipe, the chlorinated water entered
a baffled chlorine contact chamber. The
contact chamber also acted as a storage
tank, and flow through the reclamation
system was automatically adjusted
downward from its preset flow rate to
keep the tank from overfilling. Each
pressure filter flow rate limit was 950
l/m, with the system set to throttle the
flow as the contact/storage tank reached
its top 30 cm of capacity. The chlorine
dose rate was maintained to get a 3 to 4
mg/l total residual during the 1980 and
1981 seasons and about a 5 mg/l
residual during 1982.
Reclaimed wastewater was reused for
the following critical areas in fruit
processing: direct-contact container (can)
cooling, initial fruit washing and convey-
ing, and equipment washing. In addition,
reclaimed wastewater was used for floor
and gutter flushing. No washdown of
floors or equipment with the reclaimed
water was performed in areas where
splash could reach equipment that
handled peeled fruit. Reclaimed water for
gutter flushing was obtained either from
the can cooler reuse line or directly from
the reclaimed water line from the treat-
ment area. The reuse of reclaimed waste-
water in the cannery was continuous ex-
cept in the case of reclamation system
mechanical failure. In this case, the water
was only used for waste gutter flushing.
Since this use was not of a critical nature,
it was not monitored.
All processing wastewaters, product
and equipment spray drainage, spillage,
washdown waters for equipment and
floors, waters from fruit bin dumps and all
other sources except cooler overflows
were discharged to the floor gutter
drainage system. The floor gutters
drained by gravity to a sump in the
treatment area, where the wastewater
was pumped to inclined screens and then
piped to the treatment system. Cooler
water was discharged to a separate pump
sump. From this sump a portion was
pumped to the fruit-receiving area for use
in the bin dumps and for flushing water in
the gutters. The remainder was pumped
directly to the plant outfall to the Yakima
River, bypassing the treatment system.
During day-to-day operation of the
reclamation system, decision to use the
reclaimed water was based on turbidity
criteria and criteria for chlorine residual
known to indicate compliance with
bacteriological criteria. Turbidity was
continuously, automatically monitored
with a nephelometric turbidity monitor
having an alarm set point of 15 NTU and
an automatic shutdown set point of 20
NTU. Chlorine residual was monitored at
two points, ahead of the chlorine contact
tank, and at the intake to the pump that
supplied reclaimed wastewater to the
cannery reclaimed water distribution sys-
tem. The first monitoring unit supplied a
signal to the chlorination equipment to
keep the residual within a preset range.
The second chlorine residual monitor
contained alarm setpoints to be actuated
if the chlorine residual dropped below a
preset minimum.
Automatic monitoring equipment was
calibrated daily in the early morning.
Additional checks were made in the
afternoon and, if needed, the calibration
was adjusted. Most analyses were
performed according to EPA recom-
mended methods.
The project manager oversaw the
operation of the reclamation system
during the day shift. He initiated reclama-
tion and reuse at the start of each day's
processing and terminated reuse when
quality criteria were not being met.
During other shifts, any alarm condition
was handled by the process supervisor by
terminating reuse until the following day
shift, when the project manager could
rectify the problem.
To estimate the comparative can
rejection rate due to failures after cooling
in reclaimed water versus the regular
well water supply, comparable can
coolers were operated in parallel on pear
processing lines during the 1981 season
and on pear and peach processing lines
during the 1982 season. Cans were
coded for future identification. The rate of
failure of cans cooled in the two types of
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water during the two seasons was
determined by retaining all cans rejected
during labeling from the coolers and
comparing them after variable storage
periods.
Testing and Analysis of
Reclaimed Water
All routine testing of wastewater
parameters and all bacteriological analy-
ses were performed at the Snokist
Growers cannery wastewater laboratory.
Temperatures and total suspended solids
values for both well water and reclaimed
water used in the cannery were recorded
over the entire processing seasons.
Reclaimed wastewater was monitored
daily for total coliform organisms and
other aerobic bacteria by plate testing.
Less frequently, plate tests were per-
formed to monitor the presence of yeast
and mold, anaerobic organisms, and
spore-forming organisms that can sur-
vive high stress and grow under aerobic
or anaerobic conditions.
Criteria for use of reclaimed water in
critical processing areas were set as
follows: coliform bacteria (monthly mean
<1 /100 ml); total plate count for aerobic
bacteria (average of <500/ml and
maximum of 1000/ml); turbidity (< 20
NTU); and total suspended solids (<30
mg/l).
Testing for heavy metals was per-
formed by the National Food Processors
Association, Western Research Labora-
tory, Berkeley, CA, during the 1980 and
1981 seasons. Samples were shipped to
the laboratory by air after preservation
with acid. A portion of the samples was
spiked for quality control.
Testing for pesticides and polychlori-
nated biphenyls was performed by Battelle
Pacific Northwest Laboratories, Richland,
WA. Samples of well water, cannery
effluent, clarifier effluent, and reclaimed
wastewater were collected in brown
glass bottles and shipped on ice to
Battelle. Four samples of the well water,
five samples each of the cannery and
clarifier effluents, and seven samples of
the reclaimed wastewater were tested
during the 1980-81 processing season.
In addition, four well water and clarifier
effluent samples, five cannery effluent
samples, and 12 reclaimed wastewater
samples were tested during the 1981-82
season. Analysis of all samples was by
gas chromatography/mass spectrometry
using EPA Method 625 with internal
standards.
During the 1980-81 processing season,
Battelle Pacific Northwest Laboratories
analyzed 15 (12 reclaimed wastewater, 1
well water, 1 cannery effluent, and 1
clarifier effluent) samples for volatile
organic compounds. The samples were
analyzed by EPA Method 624 for "Purge-
ables." The U.S. Department of Agricul-
ture Western Regional Laboratory, Albany,
CA, was scheduled to test for halogenated
organics (volatile and nonvolatile) during
the 1980-81 processing season, but a
laboratory fire prevented completion of
this task.
Results and Discussion
Reclamation System
Performance
Performance of the reclamation system
was monitored each pear, peach, and
apple season from September-December,
and occasionally into the winter portion
of the apple processing season. (Reclama-
tion was initiated on September 10
during the 1980 and 1981 processing
seasons and on August 31 during the
1982 season.) Reclamation and reuse of
wastewater terminated on February 18,
1982, during apple processing season,
and collection of data for this project
concluded on November 8, 1982, at the
end of pear canning season.
During the period from September 10
through the end of the pear processing
season of 1980-81, reclaimed wastewater
was suitable for use on 32 of 42 days.
During the apple processing portion of
this season, the reclaimed wastewater
was suitable for use on 79 of 89
processing days. Unsuitability during the
pear season resulted almost exclusively
from mechanical failures in the treatment
system clarifier, and unsuitability during
the apple season resulted from high
turbidity.
A number of system breakdowns,
including a malfunctioning air compressor
and a broken pipe, greatly decreased the
number of days on which the reclaimed
water could be used during the 1981-82
pear processing season. The reclamation
system produced water of suitable quality
on only 34 out of a possible 59 days. Of 46
days during apple processing season,
reclaimed water was suitable for use on
only 17 days. Thus, during this season,
reclaimed water was available only 49%
of the time.
On one processing day during apple
season, water of high turbidity was
inadvertently piped to the cooler for
applesauce gallon cans. All this product
was held for 30 days until it was
determined that no container contamina-
tion had occurred. In addition, on several
days when the turbidity was within the
criteria range, the total suspended solids
were above their criteria limit of 30 mg/l.
In spite of this, the total bacterial aerobic
plate count remained below 1000/ml,
and no incidence of can failures was ex-
perienced.
All but two container coolers, an
increase over the previous season, used
reclaimed wastewater when it was of
suitable quality during the 1980-81
season. Equipment was installed so that
water overflowing the coolers could be
recycled for use in the fruit dump and
initial wash area and for gutter flushing.
Equipment was also installed to permit
bypassing waste cooling water around
the treatment system to the river outfall.
This modification which reduced the total
wastewater flow to the treatment system,
resulted in the percentage of wastewater
reclaimed not being directly comparable
to that of the 1980-81 season. The
combination of additional coolers using
reclaimed water, and a portion of the
cooler overflow being pumped directly to
the river outfall, resulted in the percentage
of total wastewater flow being higher
than in 1980, even though the poorer
water quality resulted in a lower percen-
tage of days when the water could be
reused.
Reclaimed wastewater during the
1982 fall processing season was suitable
for all 53 processing days. During this
season an improvement was made in the
capability for bypassing waste cooling
water to the plant outfall. This improve-
ment resulted in a lower flow of total
wastewater to the treatment system,
which, along with a slight increase in the
reclaimed wastewater flow, made the
percentage of processing flow reclaimed
higher than in 1980 or 1981.
The 1982 season illustrates the poten-
tial for reclamation and reuse of process-
ing wastewater. Even during this season,
however, a slight nutrient deficiency
occurred for a short time just preceding,
and probably accounting for, those days
when suspended solids were slightly
higher than the project objective.
Chemical and Microbiological
Quality of Reclaimed Water
The chemical quality of the reclaimed
water and of the well water supply was
tested at the Snokist cannery. Substantial
differences were observed between the
chemical quality of the well water supply
and the reclaimed wastewater. Primarily,
the reclaimed water had a much higher
dissolved salt content. The pH values of
the reclaimed water were lower, even
though the alkalinity averages were
about the same, and the reclaimed
wastewater had lower hardness and
calcium content.
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Reclaimed water temperature decreasd
as the processing season progressed.
Because of these lower temperatures,
after about October 1, the reclaimed
water offered an advantage over well
water for cooling cans.
Total suspended solids (TSS) content of
the clarifier effluent, the filter effluent,
and the reclaimed wastewater (i.e., filter
effluent after chlorination and retention
for contact) varied considerably during
the project. The reclaimed water quality
was better during the 1980 and 1982
seasons than during the 1981 season.
Reclaimed water quality corresponded
closely to TSS concentrations in the
biological effluent. In 1980, turbidity was
<20 NTU 92% of the time and TSS was
<30 mg/l 97% of the time (with 20 NTU
and 30 mg/l being the criteria set as ac-
ceptable at the beginning of the study). In
1982, turbidity values met these criteria
100% of the time and TSS met them 83%
of the time. In contrast, in 1981, the
turbidity criteria were met only 73% of the
time, and the TSS criteria were met only
68% of the time. This difference in water
quality most likely resulted from the many
mechanical breakdowns and nutrient-
feed deficiencies during the 1981 season,
which made the biological solids moredif-
ficult to remove.
The microbiological quality of the water
was also tested on location at the
cannery. The disinfection system was
very effective in reducing the total and
fecal coliform organism counts to within
preestablished criteria limits (monthly
mean 1/100 ml). Coliform organisms
were consistently reduced by 30 to 50%
by the filter system. Concentrations of
total aerobic bacteria in the clarifier
effluent were similar for 1980 and 1982,
with 1981 concentrations being higher.
Reduction through the filters was about
30 to 50%, similar to the reduction for
coliform organisms. In 1980, the total
plate count (TPC) for aerobic bacteria was
less than 500/ml 97.5% of the time; in
1982, it was 100%. It was 96.5% in 1981.
TPC remained below the 1000/ml maxi-
mum criteria limit at all times for all three
years. These data show that when the
turbidity and chlorine residual remained
within proper ranges, the TPC was
consistently within the preset criteria.
The filters reduced the yeast and mold
organism count by 30 to 50%. The
disinfection system appeared to be
effective at killing these organisms,
although no criteria were available to
indicate desirable levels. Organisms that
grew on anaerobic agar under anaerobic
conditions were enumerated during the
1981 and 1982 seasons. Results from
1981 indicated that the TPC for anaerobic
organisms in the clarifier and filter
effluents was one-fifth to one-tenth the
values for aerobic TPC. The effect of
disinfection was about the same as for
aerobic TPC. There were no criteria for
anaerobic TPC. Anaerobes could be
significant in cooling water, where these
organisms may enter the container, and
especially where a low-acid environment
inside the container would allow the
organisms to grow. Some organisms that
would grow in an anaerobic environment
could produce toxins inside low-acid food
containers.
Tests were run during the 1981
processing season for organisms that
formed spores resistant to boiling for 3
minutes After boiling, the samples were
tested for both aerobic TPC and anaerobic
TPC with incubation at mesophilic
temperatures. Because of the low numbers
of these organisms, the infrequency of
the testing, and the inexperience of the
technicians, it is difficult to draw any
significant conclusions from the data
obtained. However, the disinfection
system did seem to reduce their concentra-
tions.
Heavy metals tested for in the well
water, untreated cannery effluent, and
reclaimed wastewater included arsenic,
barium, cadmium, chromium, lead, mercury,
aluminum, copper, iron, manganese, tin,
and zinc. Only one value for any of the
heavy metals (chromium) exceeded the
primary drinking water standard values.
The second highest chromium value
recorded was well within the standards,
indicating that the high value was
transient in nature or a product of
sampling or analytical mishap.
Battelle reported that none of the target
pesticides or herbicides were detected in
any of the well water, cannery effluent,
clarifier effluent, or reclaimed wastewater
samples tested. Detection limits varied
but were appropriate to the MCLs for
pesticides with drinking water limitations
and were normally 10 fjg/\ or less for all
others. During 1981, Battelle also
analyzed 15 samples (12 reclaimed
water, 1 well water, 1 cannery effluent,
and 1 clarifier effluent) for volatile
organic compounds. The only volatile
halogenated organic compound confirmed
to be present was chloroform. This
compound was present either at or well
below the MCL for trihalomethanes,
including chloroform. Many literature
sources have indicated that chloroform is
generated as a byproduct of water
chlorination. The amount of chloroform m
the reclaimed water did seem to correlate
to the amount of free chlorine residual,
although the limited amount of data
precluded eliminating other potential
constituents to which it could be correlated.
Because reclaimed water is not likely to
be used for filling containers or to be
otherwise incorporated into processed
food, the presence of chloroform at these
low concentrations does not appear to be
detrimental.
To estimate the comparative can
rejection rate due to failures after cooling
in reclaimed water versus well water,
comparable coolers were operated in
parallel on pear processing lines during
the 1981 and 1982 processing seasons.
There was no apparent difference between
the failure rate among cans cooled using
reclaimed water and that of those cooled
with the well water supply for either year.
All the 1981 season undamaged rejects
were a result of inadequate lid depression,
an evidence of low vacuum. No abnormal
numbers of rejects were noted during the
1982 season. In addition, there did not
appear to be any significant difference in
cooling water bacterial counts during the
two seasons between the coolers receiv-
ing reclaimed water and those receiving
well water. The reclaimed water coolers
generally had a slightly higher chlorine
residual as a result of the chlorine
residual in the reclaimed water feed.
Based on the bacteriological quality of
water in the coolers, spoilage rates of
containers cooled by waters from the two
sources would not be expected to differ.
Conclusions and
Recommendations
The reclaimed wastewater was used in
processing high-acid (fruit) products
preserved by heat treatment for storage
in hermetically sealed containers. Since
high-acid products inherently inhibit the
growth of many microorganisms, caution
should be exercised in applying these
conclusions to any other class of food.
Based on the results of this study,
processing wastewater given good biologi-
cal treatment, filtration, and disinfection
with chlorine appears suitable for reuse
in critical areas of fruit processing.
Continuous monitoring of turbidity and
chlorine residual with an appropriate
alarm system was sufficient to protect
against using the reclaimed water when
quality criteria were not met. The quality
of the product in containers cooled in
reclaimed wastewater was not adversely
affected in this study, and the failure rate
of containers cooled in the reclaimed
wastewater was not increased in compar-
ison to containers cooled in the cannery
well water supply. Testing for potentially
hazardous constituents such as heavy
4
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metals, pesticides, and volatile organics
in the reclaimed water showed that none
of these were present m unsafe levels. In
addition, both the chemical and microbio-
logical quality of the water could be
consistently maintained throughout the
processing season when the treatment
system did not experience mechanical
failure.
The investigators recommend that the
use of reclaimed water be regulated
under the same criteria applied to any
other processing plant water supply.
Criteria guidelines should include good
biological treatment and maintenance of
low values for turbidity (not to exceed 20
NTU) and total suspended solids (a
maximum concentration of 40 mg/l). In
addition, the reclaimed wastewater
should be disinfected to comply with
drinking water regulations for total
conforms and to reduce the total aerobic
bacteriological plate count to 100/ml.
The total plate count should not exceed
1000/ml, and reclaimed wastewater
should be tested periodically for heavy
metal toxicants, as well as pesticides and
volatile organics.
Wastewater for reclamation must not
receive sanitary sewage discharges and
should contain a measurable chlorine
residual at the point of use. Continuous
online monitors of chlorine residual and
turbidity should be included in any
wastewater reclamation facility to alert
processing plant personnel of water
quality deterioration.
The use of reclaimed wastewater in
low-acid food processing plants needs to
be studied. Also, additional information is
needed regarding disinfection for anaero-
bic organisms and spores. Since the full
scope of nonvolatile and volatile halo-
genated organics testing originally
anticipated during this study was not
accomplished because of a laboratory
fire, it is also recommended that this
objective be completed when possible.
Larry A. Esvelt is with Esvelt Environmental Engineering, Spokane, WA 99206
and Herbert H. Hart is with Snokist Growers Cannery, Yak/ma, WA 98901.
David A. Brashear is the EPA Project Officer (see below).
The complete report, entitled "The Health Effect Potential of Reusing Fruit
Processing Wastewater: The Health Effect Potential of Reusing Treated Fruit
Processing Wastewater Within a Cannery,"(Order No. PB 85-137 115; Cost:
$13.00, subject to change) wilt be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
. S. GOVERNMENT PRINTING OFFICE:1985/559-I ] 1/10766
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
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