Wastewater
Reduction
and
Recycling
in
Food
Processing
Operations
State­
of­
the­
Art
Report
­­
Food
Manufacturing
Coalition
for
Innovation
and
Technology
Transfer
Statement
of
Need
Summary
The
food
processing
industry
seeks
cost­
effective
reduction
and
recycling
technologies
for
food
processing
wastewaters.
These
technologies
include
both
source
reduction
options
(
technologies
to
reduce
the
amount
of
water
used)
and
treatment
options
(
technologies
to
reduce
the
amount
or
contamination
level
of
wastewaters
requiring
discharge).

Enforcement
of
wastewater
discharge
regulations
and
escalating
sewage
surcharges
have
forced
the
food
processing
industry
to
look
for
cost­
effective
technologies
to
provide
pretreatment
or
complete
treatment
of
their
wastewaters.
Historically,
food
processors
located
within
or
adjacent
to
municipalities
have
relied
on
local
publicly
owned
treatment
works
(
POTW)
for
wastewater
treatment
and
disposal.
Increasingly,
this
option
is
becoming
less
available.
Especially
in
the
last
five
to
ten
years,
because
of
increasing
enforcement
pressure
to
comply
with
wastewater
discharge
permits
and
dwindling
federal
grants
for
constructing
new
and
upgrading
existing
treatment
works,
municipal
and
regional
sewer
authorities
are
applying
more
pressure
on
industries
to
reduce
their
organic
(
BOD
and
COD),
and
suspended
and
dissolved
solids
loading
to
the
sewers.

Background
Water
has
traditionally
been
a
key
processing
medium
in
food
processing
plants.
Water
is
used
throughout
all
steps
of
the
food
production
process,
including
food
cleaning,
sanitizing,
peeling,
cooking,
and
cooling.
Water
is
also
used
mechanically
as
a
conveyor
medium
to
transport
food
materials
throughout
the
process.
Finally,
water
is
used
to
clean
production
equipment
between
operations.
All
in
all,
food
processing
is
a
water­
intensive
operation.

Wastewater
derived
from
food
production
has
attributes
that
are
very
distinct
from
other
industrial
activities.
In
particular,
food
processing
wastewater
can
be
characterized
as
"
friendly"[
1]
in
that
it
generally
does
not
contain
conventional
toxic
chemicals
such
as
those
listed
under
EPA's
Toxic
Release
Inventory
(
with
a
few
exceptions,
such
as
phenolics
from
the
processing
of
some
plant
materials).
However,
food
processing
wastewaters
can
be
subject
to
bacterial
contamination,
which
represents
a
special
issue
for
wastewater
reuse.
More
generally,
food
processing
wastewaters
are
distinguished
by
their
generally
high
BOD
concentrations,
high
levels
of
dissolved
and/
or
suspended
solids
[
including
fats,
oils,
and
grease
(
FOG)],
nutrients
such
as
ammonia,
and
minerals
(
e.
g.,
salts).
If
separated
or
recovered,
many
of
these
constituents
have
value
in
secondary
markets.
Reclaimed
materials
have
value
through
1)
direct
in­
plant
reuse
(
e.
g.,
recovery
of
sugars
from
fruit
canning),
2)
sale
to
external
markets
(
e.
g.,
recovery
of
pasta
starch
for
animal
feed
or
for
compost),
or
3)
use
in
energy
recovery
(
e.
g.,
through
biological
or
thermochemical
gasification).

The
characteristics
and
generation
rates
of
food
wastewater
are
highly
variable,
depending
on
the
specific
types
of
food
processing
operations.
One
important
attribute
is
the
general
scale
of
the
operations,
since
food
processing
extends
from
small,
local
operations
("
the
corner
bakery")
to
large­
scale
national
or
international
producers.
This
difference
in
scale
is
relevant
not
only
in
identifying
sources
of
wastewater,
but
also
in
determining
appropriate
reduction
or
recycling
options.
In
addition
to
scale
differences,
the
types
of
food
production
processes
(
e.
g.,
fruit,
vegetable,
oils,
dairy,
meat,
fish,
etc.)
vary
widely,
with
associated
differences
in
the
specific
wastewater
contaminants.
Even
within
a
given
food
processing
plant,
the
wastewater
discharged
from
different
unit
operations­­
or
from
different
seasons­­
may
vary
with
respect
to
flow
rates
and
compositions.
These
characteristics
will
all
affect
how
readily
a
new
reduction
or
recycling
technology
can
show
a
return
on
investment
(
ROI).

In
addition
to
the
variability
in
internal
operating
conditions,
external
constraints
on
food
production
wastewater
management
also
vary
widely.
Wastewater
disposal
costs,
which
are
a
key
driver
for
reduction/
recycling
technologies,
will
vary
based
on
a
given
food
processor's
location
and
pertinent
regulatory
requirements
(
which
will
vary
by
region/
city).
Additionally,
since
byproducts
recovered
from
wastewater
streams
are
typically
of
low
bulk
density
and
marginal
economic
value,
markets
for
these
materials
often
vary
widely
regionally
and
seasonally.

As
a
result
of
these
variations
in
context
and
application,
the
determination
of
the
costeffectiveness
of
current
and
emerging
reduction
technologies
must
generally
be
made
on
a
case­
by­
case
basis.
Nonetheless,
certain
general
principles
will
apply.
First,
certain
technologies
and
operating
strategies
can
provide
an
easy
ROI
regardless
of
the
scale
of
operation.
In
addition,
certain
technologies
will
only
be
applicable
to
small
operations
(
e.
g.,
because
of
the
inherent
flexibility
of
the
production
process),
while
others
will
generally
only
apply
to
larger
operations
(
e.
g.,
because
of
high
capitalization
costs).
These
distinctions
will
be
provided
in
the
following
sections
as
relevant.

Current
Technologies
A
number
of
methods
are
used
to
reduce
wastewater
discharge
amounts
and/
or
contaminant
levels.
For
the
purpose
of
clarity,
a
distinction
will
be
made
between
source
reduction
and
treatment
technologies
as
follows:
 
Source
reduction
includes
technologies
and
operations
that
reduce
the
amount
of
wastewater
generated
in
the
first
place
 
Treatment
includes
technologies
and
operations
that
treat
wastewater
to
reduce
levels
of
contamination,
either
to
facilitate
in­
plant
recycle
or
to
reduce
costs
of
treatment
(
which
are
often
indexed
to
contaminant
concentrations).

Both
of
these
strategies
are
important
to
food
processing
and
to
wastewater
reduction
strategies.

Source
Reduction
A
series
of
simple
techniques
are
currently
available
as
a
first
stage
in
minimizing
wastewater
generation.
These
techniques
represent
generally
low­
investment
options
that
are
available
to
virtually
all
food
processing
operations
regardless
of
size.
The
techniques
can
be
generally
categorized
into
two
groups:
1)
techniques
to
minimize
the
amount
of
food
(
or
other)
waste
that
becomes
water­
borne,
and
2)
techniques
to
optimize
the
use
of
water.

The
objective
of
preventing
food
or
other
waste
from
becoming
waterborne
is
to
keep
"
dry
waste
dry
and
wet
waste
wet."
Approaches
currently
being
used
include
dry
cleanup
before
floor
rinsing
and
manually
cleaning
vessels
before
rinsing
to
remove
solids
for
recovery
or
disposal.
Other
approaches
focus
on
changing
production
procedures
to
minimize
product
or
byproduct
wastage,
such
as
installing
spill
collection
trays
to
collect
solids
at
appropriate
places
in
the
production
line.
In
addition,
water­
based
conveyor
systems
can
be
replaced
by
mechanical
systems
(
augers
or
conveyors).

Optimizing
the
use
of
water
includes
techniques
such
as
modernizing
water
sprays
to
include
jets
or
nozzles,
using
high­
pressure
low­
volume
washing
systems,
and
auto
shutoff
valves
[
5].
Other
more
capital­
intensive
options
include
installing
clean­
in­
place
(
CIP)
systems.
Finally,
one
important
option
includes
improving
operations
and
maintenance
programs
to
identify
process
upsets,
problems,
or
malfunctions
early
in
the
process
so
as
to
minimize
the
amount
of
waste
produced
and
wastewater
generated.
This
process­
control
based
strategy
is
also
an
important
area
of
emerging
technology,
as
improved
sensors
and
control
algorithms
become
available.

Treatment
Because
water
is
ubiquitous
throughout
food
processing
plants,
in­
plant
treatment
of
wastewater
as
a
means
of
permitting
reuse
in
other
parts
of
the
plant
is
a
key
strategy.
A
wide
range
of
treatment
options
is
currently
being
used
to
minimize
the
amount
of
wastewater
generated,
or
to
reduce
the
concentration
of
contaminants
in
the
wastewater.

Retention/
redirection
simply
means
determining
uses
for
wastewater
other
than
discharge
to
the
POTW.
Examples
of
redirection
include
using
"
clean"
wastewater
for
initial
floor
scrubdown
or
using
nitrogen­
rich
wastewater
as
a
fertilizer
for
plant
grass
areas
[
7].
As
with
any
wastewater
reuse,
these
approaches
require
close
attention
to
regulatory
requirements.

Separation/
concentration
technologies
provide
a
means
of
separating
out
solids
or
other
materials
from
wastewaters.
Low­
technology
options
include
installing
drain
screens,
settling
basins,
berms,
or
systems
to
separate
waste
products
out
of
wastewater
before
it
is
discharged.
Other
common
technology
options
currently
in
use
include
the
following
(
information
relies
heavily
on
[
2]):

 
Centrifugation
is
useful
for
oil/
water
separation
and
for
large
particle
separation
(
solids
of
particles
sizes
ranging
from
1
to
5000
microns.
Particles
greater
than
5000
microns
(
5
mm)
may
require
pretreatment
(
grit
removal
or
grinder)
before
centrifugation.
Several
different
types
of
centrifuges
are
available,
including
basket,
solid­
bowl,
countercurrent­
flow
and
concurrent­
flow
systems.
Costs
range
from
$
60
to
$
2,000
per
million
gallons
treated.
 
 
Evaporation
is
well
suited
for
wastewaters
containing
primarily
inorganic
salts.
There
are
two
primary
types
of
evaporators:
mechanical
evaporators
and
evaporation
ponds.
Mechanical
evaporators
require
an
energy
source,
but
can
allow
for
water
recovery.
Foaming,
scaling,
and
fouling
are
typical
operational
difficulties,
which
may
require
ancillary
treatment
systems.
Technology
costs
can
vary
widely
from
$
20
(
ponds
under
minimal
regulatory
constraints)
to
over
$
10,000
(
thermomechanical
system)
per
million
gallons
treated.

I.
Filtration
is
used
primarily
to
reduce
suspended
solids
or
oils
and
grease.
Filtration
is
generally
used
as
a
pretreatment
step
or
a
final
wastewater
"
polishing"
step
before
discharge.
Several
different
types
of
filters
exist,
including
granular­
media,
cartridge,
membrane,
and
diatomaceous
earth
precoat
filters.
The
most
common
in
the
food
processing
industry
include
cylindrical
or
pleated
cartridge
filters,
belt
and
press
filters,
vacuum
filters,
hydrosieves,
and
continuous
scraped
surface
filters
[
1].
Filtration
is
generally
effective
for
particles
larger
than
about
1
micron
in
size.
Costs
can
vary
from
$
20
to
over
$
100
per
million
gallons
treated.

II.
Flotation
is
another
treatment
for
suspended
solids
or
oils
and
grease.
Flotation
generally
involves
passing
gas
bubbles
through
the
wastewater.
The
gas
adheres
to
water
contaminants
and
causes
them
to
rise
to
the
surface
into
froth
where
they
can
be
skimmed
off.
Dissolved
air
flotation
(
DAF)
and
induced
air
floatation
(
IAF)
are
the
two
principal
types
of
flotation.
Costs
can
vary
from
$
20
to
over
$
100
per
million
gallons
treated.

III.
Gravity
separation
can
occur
in
settling
ponds
or
in
specific
vessels
and
is
useful
for
materials
with
significantly
different
densities
than
water,
such
as
oils
and
grease
(
which
would
rise
to
the
surface
to
be
skimmed)
or
various
suspended
solids
(
which
would
generally
sink
to
the
bottom).
Costs
can
range
from
$
50
to
$
500
per
million
gallons
treated.
IV.
Membrane
systems
represent
a
primary
source
of
separation
for
the
food
processing
industry.
Many
different
types
of
membrane
systems
are
currently
in
use.
Because
of
the
intensive
research
currently
being
conducted
on
this
topic,
membrane
systems
will
be
addressed
in
full
under
Emerging
Technologies
below.

Conversion
of
constituents
into
more
manageable
or
valuable
forms
includes
the
fermentation
of
sugars
to
alcohol,
apple
waste
to
vinegar,
or
enzymatic
conversion
of
starch
to
fructose
[
1].
Because
conversions
are
fairly
complex
and
site­
dependent,
their
application
is
currently
limited;
however,
opportunity
for
these
types
of
conversions
may
grow
as
the
product
value
of
byproducts
becomes
more
clearly
identified.

Biotreatment
involves
the
use
of
a
biological
reactor
that
contains
a
high
specific
concentration
of
either
suspended
or
attached
growth
microorganisms
[
2].
As
wastewater
is
passed
through
the
reactor,
the
microorganisms
metabolize
organic
compounds
into
carbon
dioxide.
Both
aerobic
and
anaerobic
technologies
exist.
A
detailed
treatment
of
these
technologies
and
their
limitations
is
provided
in
the
State­
of­
the­
Art
Report
on
BOD
which
was
prepared
by
the
Food
Manufacturing
Coalition.

An
important
type
of
chemical
treatment
is
the
use
of
gaseous
chlorine
and
chlorine
derivatives
to
address
bacterial
contamination.
Because
of
safety
concerns
about
the
potential
generation
of
chlorine
by­
products,
newer
technologies
being
tested
include
ozonation
and
ultraviolet
light
treatment
(
covered
below).

Finally,
incineration
is
a
treatment
approach
that
can
be
coupled
to
other
systems
(
filtration,
flotation,
etc.)
to
provide
final
disposal
of
food
waste
byproducts
[
2].
Incineration
can
be
used
to
treat
essentially
all
forms
of
waste,
including
concentrated
wastewater,
liquid
wastes,
solid
wastes,
gases,
and
sludges.
Forms
of
incinerators
include
liquid
injection,
fluidized
bed,
and
rotary
kiln
incinerators.
Clearly,
this
approach
is
problematic,
given
the
high
cost
of
technology
deployment
(
more
than
$
1
million
per
million
gallons
treated),
as
well
as
the
heavy
regulatory
and
public
scrutiny
it
faces.
It
also
represents
a
high­
intensity
approach
to
waste
management
that
creates
potentially
problematic
secondary
waste
(
ash)
and
bypasses
the
option
to
reuse
food
waste
products.

Emerging
Technologies
Source
Reduction
Pneumatic
(
Air­
Based)
Transport
­
Water
has
historically
been
a
common
transport
medium
in
food
production.
There
exist
increasing
opportunities
for
non­
water
based
transport.
Pneumatic
transport
is
currently
used
in
facilities
ranging
from
coffee
bean
preparation
to
flour
milling
[
3].

Process
Modeling
­
A
significant
source
of
wastewater
arises
from
improperly
adjusted
process
activities
that
lead
to
product
wastage.
Process
modeling
is
a
technique
to
use
computers
to
optimize
process
conditions.
Process
modeling
will
help
fine­
tune
such
input
parameters
as
material
or
water
flow
velocity,
temperature,
and
chemical
concentration,
as
well
as
vessel
design
(
e.
g.,
input/
output
configuration)
and
overall
process
configuration.
A
major
brewery
used
this
technique
to
improve
the
product
quality
and
batch
repeatability
of
their
brewing
process
by
identifying
both
an
improved
mixing
blade
design
for
the
mash
tubs
and
a
change
in
water
application
rates,
thus
reducing
liquid
product
wastage
[
3].
Another
application
by
a
decaffeinated
coffee
manufacturer
improved
timing­­
and
thus
the
efficiency­­
of
the
caffeine
separation
process.
Process
modeling
can
also
support
optimization
of
material
flow
through
processing
tanks
(
e.
g.,
activated
charcoal)
to
avoid
areas
of
dead
flow
that
allow
bacterial
buildup
[
3].

Process
Sensors
and
Control
­
Related
to
process
modeling,
process
sensors
and
control
represent
computer
systems
and
other
in­
process
sensors
to
identify
and
control
the
production
process
in
real­
time.
Process
sensors
and
controls
are
common
and
well
developed
in
the
chemical
manufacturing
industry.
Emerging
techniques
such
as
Artificial
Neural
Network
(
ANN),
model­
predictive
and
fuzzy­
logic­
based
control
all
promise
improved
control
of
washing,
blanching,
cooling,
and
cooking
operations
that
can
result
in
reduced
wastewater
loads
and
higher
yields.
Along
with
new
optimization
techniques
such
as
genetic
algorithms,
these
concepts
could
be
extended
to
improving
the
scheduling
of
sequential
batch
operations,
food
production
vessel
cleaning,
rinse
water
control,
and
similar
applications
to
reduce
water
demand.

Low
or
No­
Water
Cooking
and
Processing
­
Continuation
of
industry
trends
towards
lower
water
use
(
such
as
steam
blanching
and
microwave
drying)
can
be
expected
to
continue
as
the
technology
improves
and
the
cost
and
regulatory
drivers
for
reduced
water
consumption
increase.
Many
of
the
emerging
technologies
are
being
explored
under
the
aegis
of
the
EPRI
Food
Technology
Center
and
include
such
concepts
as
high
hydrostatic
pressure
or
electric
field
processing.
The
underlying
concept
in
all
of
these
technologies
is
to
find
non­
thermal
means
of
destroying
microorganisms
that
present
food
deterioration
or
safety
concerns.
In
applications
such
as
blanching
or
pasteurization,
these
technologies
present
an
opportunity
to
eliminate
the
use
of
steam
and/
or
hot
water,
resulting
in
reduced
wastewater
production.
Other
specialized
technologies
being
developed
include
the
use
of
ohmic
(
electrical)
thawing
of
frozen
foods
to
replace
water
bath
immersion
and
direct
electrical
or
plasma
pasteurization
of
meats
and
poultry.

Integrated
WaterReuse
­
Although
integrated
water
reuse
does
not
rely
on
a
specific
technology,
interest
and
experience
in
total
integration
of
water
demands
in
manufacturing
through
heat
recovery,
"
cascading"
of
wastewater
streams,
and
byproduct
recovery
from
concentrated
streams
are
growing.
Emerging
techniques
such
as
the
extension
of
"
pinch"
design
technology
(
an
energy
integration
strategy
that
has
proven
very
successful
in
the
chemical
and
refining
industry)
to
wastewater
reuse
hold
some
promise
for
identifying
integration
opportunities.
However,
successful
application
of
this
design
approach
depends
in
large
degree
on
the
improvement
of
key
reduction
and
treatment
technologies,
especially
disinfection
(
UV,
ozone,
plasma)
and
separations
methods.
Treatment
Membrane
Applications
­
As
mentioned
above,
membrane
systems
represent
a
primary
source
of
separation
for
the
food
processing
industry.
In
addition,
they
represent
one
of
the
most
active
areas
of
current
research
and
emerging
technologies.
The
following
discussion
relies
heavily
on
[
2],
[
9],
and
[
11].

Membrane
processes
employ
a
semipermeable
membrane
and
osmotic
or
other
pressure
differential
to
force
materials
(
water
or
contaminants)
across
the
membrane.
The
most
common
configuration
in
food
processing
application
is
designed
to
have
water
pass
through
a
membrane
as
permeate,
with
dissolved
solids
or
other
constituents
captured
as
retentate.
Membrane
materials
are
typically
organic
polymers,
although
new
types
of
inorganic
polymer,
ceramic,
and
metallic
membranes
are
currently
being
investigated
and
deployed.

Membranes
are
commonly
used
by
a
number
of
process
industries,
including
chemicals,
food,
pulp
and
paper,
and
power
generation.
Within
the
food
industry,
membrane
technologies
have
been
in
use
for
at
least
15
years
for
such
applications
as
concentrating
whey
in
the
dairy
industry,
clarifying
juices
and
other
beverages,
and
reclaiming
sugars
from
fruit
processing.
New
materials
and
technologies
are
continuing
to
expand
the
range
of
economic
applications
into
other
areas
of
food
water
treatment
and
product
recovery.

The
basic
membrane
systems
commercially
available
include
microfiltration,
ultrafiltration
(
UF),
and
reverse
osmosis
(
RO),
each
of
which
treats
a
different
range
of
particle
sizes.
Specifically,
microfiltration
generally
addresses
the
largest
constituents
­
that
is,
from
0.05
­
2
microns;
ultrafiltration,
middle­
range
constituents
from
0.005
­
0.1
microns;
and
reverse
osmosis,
smaller
constituents
in
the
Angstrom
range
(
e.
g.,
molecular
weight
above
200).
In
practice,
this
means
that
microfiltration
of
food
processing
wastewater
can
separate
microbes;
UF
separates
microbes
and
suspended
solids;
while
RO
can
separate
microbes,
suspended
solids,
and
dissolved
solids.
RO
is
notable
in
that
when
coupled
with
ozonation
or
other
sterilization,
it
is
capable
of
generating
drinking
quality
water.
Newer
technologies
include
nanofiltration
(
also
known
as
ultraosmosis),
which
generally
covers
a
range
of
particles
between
UF
and
RO.

Common
configurations
of
membrane
systems
include
plate­
and­
frame,
spiral
wound,
tubular,
and
hollow
fiber
modules.
The
plate­
and­
frame
is
a
flat
sheet
membrane,
with
alternating
layers
of
membrane
and
spacer/
permeate
carrier
plating
that
creates
a
sandwich
effect.
It
is
one
of
the
simplest
(
and
cheapest)
configurations
used.
The
spiral
wound
design
is
an
extension
of
plate­
and­
frame
that
basically
wraps
the
membrane
sandwich
around
a
collection
pipe
into
which
the
permeate
is
directed.
This
design
provides
higher
membrane
packing
density
than
the
plate­
and­
frame,
but
also
increases
the
opportunity
for
clogging.
Tubular
modules
are
designed
following
the
structure
of
heat
exchangers,
with
a
series
of
hollow,
thin­
walled
membrane
tubes
used
to
carry
the
feed
stream.
By
increasing
the
size
of
the
tubes
(
up
to
2
cm),
one
can
treat
water
with
higher
levels
of
suspended
solids
or
with
more
viscosity;
however,
such
systems
require
higher
pumping
energy
and
represent
greater
capital
and
operating
costs.
Finally,
hollow
fiber
modules
consist
of
tiny,
hollow,
hair­
like
membrane
fibers
bundled
together
inside
a
pressurized
vessel.
As
the
feed
stream
enters
the
space
surrounding
the
fibers,
permeate
passes
through
into
the
center
of
the
fibers
and
is
carried
away.
Hollow
fiber
modules
allow
high
packing
density
and
require
lower
pressure
drops,
leading
to
systems
with
both
lower
capital
and
operating
costs.
However,
these
modules
are
delicate
and
highly
susceptible
to
fouling.

Fouling
is
a
major
issue
for
membrane
systems
[
1].
Fouling
results
from
material
buildup
that
blocks
fluid
flow
across
the
membrane.
Reverse
osmosis
is
particularly
susceptible
to
blockage.
Temperature,
solute­
solute,
and
solute­
membrane
interactions
all
affect
the
fouling
process.
One
common
means
of
addressing
fouling
is
to
provide
high
cross
flow
velocities
to
reduce
the
thickness
of
the
build­
up,
and
to
control
pressure
and
permeate
recovery.

Newer
designs
for
membrane
systems
include
centrifugal
and
vibrational
systems,
both
of
which
are
designed
to
limit
buildup
of
solids
along
membrane
surfaces.
Other
specialized
types
of
membrane
separation
processes
include
pervaporation,
which
is
the
separation
of
more
volatile
compounds
out
of
a
liquid
into
a
gas,
and
electrodialysis,
which
involves
the
separation
of
ions
from
a
solution
across
an
electrically
charged
membrane.
These
are
currently
less
common
in
food
applications.

Membrane
configurations
often
include
multiple
membrane
or
other
systems.
For
example,
Zenon
Environmental
Inc.
has
developed
a
membrane
biological
reactor
that
combines
an
ultrafiltration
process
with
a
biological
reactor.
This
system
maintains
a
high
biomass
concentration
while
continuously
removing
the
clarified
permeate
with
zero
BOD
[
1].
Among
other
advantages,
this
approach
significantly
minimizes
the
space
requirements
of
biological
systems
for
holding
tanks
and
sludge
handling.

Membrane
systems
can
show
several
advantages
over
other
conventional
separation
treatments
(
evaporation
and
distillation),
including
lower
energy
use,
smaller
space
requirements,
better
control
of
microbes
and
organic
matter
in
the
process
effluent,
and
improved
product
quality.
In
addition,
unlike
vaporization
and
freeze
concentration,
membrane
separation
does
not
require
temperature
and
phase
changes
of
the
selected
components
[
10].

Ongoing
research
in
membrane
separation
techniques
involves
exploration
of
new
membrane
materials
and
of
new
module
design
configurations
to
address
issues
of
fouling
and
treatment
of
difficult
waste
streams
(
high
suspended
solids
or
viscous
waste
streams).
Of
particular
interest
to
the
food
industry
are
1)
the
cost­
effective
separation
of
waters
with
high
dissolved
and
suspended
solids,
and
2)
the
treatment
of
microbes.
Microbial
treatment
is
particularly
noteworthy
as
food
safety
issues
limit
many
types
of
wastewater
minimization
opportunities.
In
addition
to
these
issues,
much
attention
in
membrane
separation
for
the
food
industry
is
being
given
to
demonstration
efforts
that
provide
bench­
and
pilot­
scale
testing
of
membrane
configurations
for
specific
food
processing
applications.
A
major
membrane
demonstration
effort­­
the
mobile
Membrane
Test
and
Demonstration
Unit
(
MTDU)­­
has
been
in
operation
primarily
on
the
west
coast
since
1992
[
10].
This
trailer
has
recently
been
supplemented
by
MTDU2,
a
second
trailer
designed
to
operate
on
the
east
coast.
These
mobile
trailer
units
include
a
variety
of
membrane
materials
and
configurations
to
provide
wide­
ranging
test
conditions.
The
objective
of
this
effort
is
to
demonstrate
the
application
of
membrane
separation
technology
in
various
food
plants
as
a
effective
method
to
reduce
effluent
contaminants,
conserve
water
and
energy,
and
recover
byproducts.
The
project
is
conducted
by
the
California
Institute
of
Food
and
Agricultural
Research,
under
the
sponsorship
of
the
Electric
Power
Research
Institute
(
EPRI)
and
several
other
sponsors,
including
various
utilities,
the
U.
S.
Department
of
Energy
(
through
Pacific
Northwest
National
Laboratory),
the
California
League
of
Food
Processors,
the
National
Food
Processors
Association,
and
others.
The
MTDU
trailer
has
traveled
to
18
sites
in
10
states
as
of
January
1996
and
has
completed
membrane
studies
of
processing
plants
including
fruit,
dairy,
pasta,
fermentation
products,
soft
drinks,
confectionery,
and
seafood.

Performance
experience
with
membrane
technology
has
shown
important
cost
savings.
EPRI
reports
of
16
MTDU
case
studies
[
12
and
13]
shows
that
several
applications
were
cost­
effective.
In
some
cases­­
including
the
treatment
of
raisin
washwater,
peach
processing
water,
and
peach
pitter
water­­
the
net
cost
savings
were
driven
by
byproduct
recovery.
For
example,
a
Dole
Raisin
Plant
experienced
a
capital
cost
of
$
250,000
and
annual
operating
costs
of
$
82,000
for
a
membrane
treatment
system;
however,
annual
benefits
due
to
recovery
of
sugar
concentrate
were
estimated
at
$
528,710
[
12].
In
other
cases,
the
cost­
effectiveness
of
the
treatment
was
based
on
reduced
disposal
costs,
such
as
the
reduction
in
BOD
charges
at
a
vegetable
processing
plant
through
treatment
of
carrot
peeler
wash
water
[
12].
This
type
of
cost
is,
of
course,
highly
site­
dependent.
In
a
few
other
cases,
indirect
benefits
made
the
difference
in
the
treatment
of
the
costeffectiveness
For
example,
even
though
direct
benefits
of
membrane
technology
at
the
Hunt­
Wesson
tomato
processing
plant
did
not
exceed
costs,
the
improved
effluent
treatment
levels
enabled
the
plant
to
extend
its
period
of
operation.
In
this
case,
increased
production
outweighed
the
additional
treatment
expenses
by
a
wide
margin
[
12].

As
another
example
outside
of
the
EPRI
program,
a
combination
UF/
RO
system
implemented
at
a
Kraft
plant
to
treat
bakery
wastewater
showed
net
annual
savings
of
$
600,000
[
1].
Savings
included
reduction
in
BOD
surcharge,
wastewater
discharge
volume
charge,
sludge
volume,
and
labor.
Costs
include
the
annual
O&
M
costs
of
the
system
($
600,000
for
a
125
gpm
system).
This
system
is
expected
to
show
a
full
payback
of
design
and
installation
costs
in
less
than
3
years.

Other
Separation
Techniques
­
Other
separation
techniques
that
facilitate
recovery
of
suspended
solids
from
wastewater
streams
are
being
developed.
Two
examples
are
acoustic
separation
and
electro­
osmotic
dewatering.
These
technologies
use
an
applied
acoustic,
electrical,
or
combined
field
to
enhance
the
rate
and
efficiency
of
separation.
They
are
typically
targeted
towards
suspended
solids
and
can
reduce
wastewater
generation
by
making
it
more
economically
viable
to
recover
solids
from
high
solids
streams.
The
U.
S.
Department
of
Energy,
Office
of
Industrial
Technology
is
currently
sponsoring
a
project
in
this
area:
the
Improved
Electroacoustic
Dewatering
Belt
Press
for
Food.

High
Energy
Systems
­
Over
the
past
several
years,
research
interest
in
high­
energy
approaches
to
wastewater
treatment
has
increased.
The
term
"
high
energy"
refers
to
the
fact
that
these
technologies
(
such
as
Corona
discharge
and
plasma
reactors)
use
highly
excited,
or
energetic
fields,
to
treat
the
waste.
These
technologies
are
largely
being
explored
for
their
potential
in
destroying
pathogens
and
reducing
BOD
loading
in
high
BOD
wastewater
streams.
They
are
not
generally
applicable
to
high
ionic
strength
(
salt
and
brine
solution)
streams,
which
remain
as
a
critical
challenge
to
wastewater
reuse.

The
EPRI
Food
Technology
Center
is
currently
proposing
a
research
partnership
to
develop
a
silent
electric
discharge
(
SED)
reactor
for
improving
the
safety
and
efficiency
of
recycling
processing
water
[
15].
The
criteria
for
success
will
be
improved
BOD
and
COD
removal
with
less
cost
than
conventional
ozone
generators.

Sterilization
­
Ozonation
and
ultraviolet
light
treatment
are
being
tested
as
methods
to
provide
sterilization
and
reduce
bacterial
counts,
permitting
closed­
loop
recycling
of
rinse
and
chiller
waters.
Ozonation
works
in
a
manner
similar
to
chlorine
disinfection
(
in
both
technologies,
a
reactive
gas
is
introduced
to
the
wastewater
stream
to
chemically
disinfect
the
stream),
but
avoids
the
concern
of
introducing
chlorinated
organic
compounds
to
the
wastewater
stream.
Ultraviolet
disinfection
can
be
used
especially
in
low­
concentration
wastewater
streams
(
or
high­
concentration
streams
with
high
clarity)
to
permit
reuse
of
the
water.
It
is
of
particular
interest
in
applications
such
as
chiller
water
recycling,
where
pathogenic
contamination
is
the
primary
obstacle
to
recycling
of
the
water
stream.
These
technologies
are
closely
related
to
other
"
high
tech"
field­
enhanced
techniques
described
under
the
emerging
source
reduction
category.

An
ozone
demonstration
project
is
currently
being
sponsored
by
EPRI
and
conducted
by
scientists
at
the
University
of
Arkansas
with
engineers
from
American
Water
Purification,
Inc.
[
14].
The
first
phase
of
this
demonstration
project
includes
a
Mobile
Ozone
Treatment
Laboratory
(
MOTL);
phase
II
will
extend
the
demonstration
to
include
membrane
testing.
This
project
is
focused
on
the
poultry
industry,
with
the
intent
of
addressing
the
rising
concern
over
food
safety
and
quality
and
regulatory
compliance
in
poultry
processing
plants.
The
MOTL
will
conduct
on­
site
tests
of
ozonation
of
poultry
chiller
water.

Conversion
­
Research
is
being
conducted
on
new
methods
for
converting
food
byproducts
to
more
valuable
products.
Argonne
National
Laboratory
is
investigating
the
opportunity
for
large­
scale
production
of
lactic
acid
and
its
derivatives
from
carbohydrate
wastes
[
8].
The
conversion
train
for
this
process
includes
fermentation,
primary
and
secondary
purification,
and
various
polymerization
technologies.
Traditionally,
lactic
acid
is
purified
by
adding
sulfuric
acid
to
the
fermentation
broth
that
contains
calcium
lactate.
This
step
generates
large
volumes
of
calcium
sulfate
salt
waste.
By
contrast,
the
Argonne
primary
purification
process
uses
advanced
desalting
and
water­
splitting
electrodialysis
technologies
that
purify
the
lactic
acid
without
generating
a
salt
waste
stream.
In
addition
the
Argonne
process
includes
the
use
of
a
different
chemical
pathway
to
facilitate
high­
volume
manufacture
of
several
different
lactic
derivatives.

Fuel
Conversion
­
Though
interest
in
fuel
recovery
from
wastewater
streams
is
not
as
intense
as
it
once
was,
research
and
development
continues
on
the
development
of
efficient,
robust
systems
for
recovery
of
energy
value
from
high­
concentration
wastewater
streams.
Both
biological
(
anaerobic
digestion)
and
thermochemical
(
catalytic
reduction)
technologies
exist,
as
well
as
hybrid
systems
which
combine
both
technologies.
In
general,
the
applicability
of
these
systems
is
limited
to
relatively
high
concentration
(>
2
weight
%
organic)
streams
with
high
BOD
loadings,
and
relatively
low
inorganic
(
brine
or
salt)
concentration.

Next
Steps
for
Technology
Implementation
This
report
has
identified
a
wide
range
of
emerging
technologies
and
techniques
for
reducing
and
recycling
wastewater
in
the
food
processing
industry.
To
date,
the
food
industry
has
been
a
part
of
this
technology
development
process
through
several
joint
initiatives
to
pool
resources
and
sponsor
development
and
demonstration
projects
[
see
particularly
references
9
through
14].
Many
of
these
initiatives
are
collaborations
among
committed
allies,
including
EPRI
and
the
utility
industry,
the
Department
of
Energy
(
through
the
Office
of
Industrial
Technology
and
other
offices),
as
well
as
many
statelevel
Waste
Minimization
Programs.

While
a
significant
amount
of
progress
has
been
accomplished
to
date,
further
opportunities
for
collaboration
in
technology
development
remain.
This
collaboration
can
be
shaped
in
a
number
of
ways.
The
following
list
represents
one
perspective­­
a
complementary
set
of
activities
that
span
the
range
from
basic
research
to
information
exchange.

I.
Pre­
competitive
Research
­
The
food
processing
industry
should
pursue
opportunities
to
work
jointly
on
research
topics
that
are
still
at
the
pre­
competitive
stage;
that
is,
the
stage
where
expected
results
would
not
be
proprietary.
One
example
is
in
the
area
of
advance
fuzzy
logic
control
for
water­
intensive
processes.
Based
on
the
experience
in
the
chemical
industry,
there
is
good
reason
to
believe
that
fuzzy
logic
control
could
lead
to
significant
process
improvements
for
the
food
processing
industry.
However,
basic
research
questions
remain.
Because
this
type
of
research
area
is
likely
to
be
outside
the
scope
of
any
individual
food
processor,
a
collaborative
effort
is
needed
to
ensure
progress.

II.
Demonstration
Project
­
The
food
processing
industry
should
continue
to
sponsor
demonstration
projects
in
wastewater
reduction
and
recycling,
particularly
in
the
area
of
membrane
technology.
The
MTDU
program­­
in
which
the
National
Food
Processors
Association
and
Pacific
Northwest
National
Laboratory
have
already
been
participating­­
has
shown
some
significant
progress
in
testing
and
demonstrating
various
membrane
systems
for
wastewater
management.
One
significant
area
of
application
that
remains
to
be
adequately
demonstrated
is
the
membrane
treatment
of
meat
and
poultry
wastewaters.
In
particular,
a
significant
challenge
is
to
provide
membrane
treatment
that
allows
water
reuse
while
completely
addressing
issues
of
bacterial
contamination.
The
food
industry
should
leverage
experience
gained
under
previous
MTDU
tests
by
creating
a
new
initiative
to
demonstrate
the
value
of
membrane
technology
in
providing
safe,
clean,
and
cheap
water
management
for
the
meat
and
poultry
industry.

III.
Management
of
Regulatory
and/
or
Public
Perception
Issues
­
Successful
technology
deployment
depends
on
adequately
resolving
regulatory
and
public
perception
issues;
the
best
technology
will
fail
if
its
sponsors
do
not
attend
to
these
issues.
Accordingly,
the
food
processing
industry
should
initiate
a
collaborative
issues
management
program.
Such
a
program
would
be
designed
to
proactively
address
issues
in
regulatory
and
public
perception
related
to
new
wastewater
reduction
and
recycling
technologies.
For
example,
the
program
could
work
to
ensure
that
regulations
are
developed
that
allow
chiller
water
recycling
while
still
fully
protecting
public
health.

IV.
Information
Exchange
­
To
support
the
above
substantive
areas
for
collaboration,
efforts
to
create
greater
information
flow
across
the
industry
would
also
be
useful.
The
food
processing
industry
should
establish
an
industry
forum
to
review
and
compare
best
practices
in
wastewater
reduction.
This
forum
might
include
a
national
database
on
experiences
with
new
technologies
and
techniques
of
wastewater
reduction,
an
information
clearinghouse
or
networking
service,
and/
or
periodic
national
conferences
or
workshops.

Much
change
is
in
store
for
the
food
processing
industry
over
the
next
decade,
as
production
processes
become
more
automated
and
computerized
and
more
oriented
towards
integrated
systems.
At
the
same
time,
the
expectations
of
customers,
government
regulators,
and
the
public
for
both
environmental
performance
and
product
quality
are
likely
to
increase.
An
active
effort
to
develop
and
deploy
emerging
wastewater
reduction
technologies­­
technologies
that
reduce
wastewater
loads,
save
energy,
and
insure
public
health­­
should
serve
the
industry
well
in
responding
to
these
changing
conditions.

REFERENCES
1.
Nini,
D.,
and
P
Gimenez­
Mitsotakis,
"
Creative
Solutions
for
Bakery
Waste
Effluent,"
American
Institute
of
Chemical
Engineers,
Symposium
Series,
No.
300,
Vol.
90:
95­
105.

2.
Byers,
W.,
et
al.,
How
to
Implement
Industrial
Water
Reuse:
A
Systematic
Approach,
Center
for
Waste
Reduction
Technologies,
American
Institute
of
Chemical
Engineers,
New
York,
NY,
1995.

3.
Airflow
Sciences
Corporation,
"
Applications
for
Process
Industries,"
1
Watling
Drive,
Sketchley
Business
Park,
Hinckley,
Leics,
LE10
3EY,
Great
Britain
4.
Hayes,
C.,
"
Fish
Processing
Case
Study:
Reduction
of
Biological
Oxygen
Demand,"
Pollution
Prevention
Report,
Illinois
Hazardous
Waste
Research
and
Information
Center,
Chicago,
IL,
1996.

5.
Carawan,
R.
E.,
"
Liquid
Assets
for
Your
Bakery,"
Water
Quality
and
Waste
Management
Division,
North
Carolina
Cooperative
Extension
Service,
Publication
Number
CD­
41,
1996.

6.
"
Using
Food
Processing
By­
Products
for
Animal
Feed,"
Water
Quality
and
Waste
Management
Division,
North
Carolina
Cooperative
Extension
Service,
Publication
Number
(
unknown),
1996.

7.
"
CASE
STUDY:
Eagle
Snacks,
Inc.,"
SIC
2000
Case
Studies,
North
Carolina,
1995.

8.
Tsai,
S­
P.,
"
Food­
Processing
Waste
Converted
to
Valuable
Chemical
Products,"
Argonne
National
Laboratory
Web
Site,
http://
www.
es.
anl.
gov/
htmls/
food.
process.
html.

9.
"
Membrane
Processes,"
TechCommentary,
EPRI
Process
Industry
Coordination
Office,
1
(
2),
1988.

10.
Moore,
T.,
"
A
Separable
Feast:
Membrane
Applications
in
Food
Processing,"
EPRI
Journal,
September,
1994:
17­
23.

11.
Merlo,
C.
A.,
W.
W.
Rose,
and
N.
L.
Ewing,
"
Membrane
Filtration
Handbook/
Selection
Guide:
A
Guide
on
Membrane
Filtration
Technology
for
the
Food
Processing
Industry,"
National
Food
Processors
Association,
Dublin,
CA,
August,
1993.

12.
Mannapperuma,
J.
D.,
et
al.,
"
Membrane
Applications
in
Food
Processing,
Volume
1:
Fruit
and
Vegetable
Processing
Industry,"
EPRI
Process
Industries
Offices,
Food
and
Agriculture
Office,
PIO
Report
CR­
105377­
V1,
July,
1995.

13.
Mannapperuma,
J.
D.,
et
al.,
"
Membrane
Applications
in
Food
Processing,
Volume
2:
Algin
Fiber,
Pasta,
Dairy,
Fruit,
and
Wine
Processing
Industries,"
EPRI
Food
Technology
Center,
FTC
Report
CR­
105377­
V2,
September,
1995.

14.
"
Improving
Poultry
Industry
Competitiveness:
A
Collaborative
Project,"
EPRI
Food
Technology
Center
Target
Summary,
CR­
105173R2,
Food,
September
1996.

15.
"
Comparison
Studies
Between
Conventional
Corona
Discharge
&
Plasma
(
SED)
Reactors
for
Treatment
of
Food
Processing
Waste
Water
Project,"
EPRI
Food
Technology
Center
Target
Summary,
CR­
105173R2,
Food,
September
1996.

March
1997
For
additional
information,
contact:

R.
J.
Philips
&
Associates,
Inc.
Systems
Manager,
Food
Manufacturing
Coalition
P.
O.
Box
741
Great
Falls,
Virginia
22066
(
703)
406­
0072
(
phone)
(
703)
406­
0114
(
fax)
E­
mail:
rphil1140@
aol.
com
