New process saves poultry processor millions of gallons of water.
Water treatment is a critical
factor for the poultry processing industry. Large operations process upwards of
300,000 birds per day, and use between 3–6 gallons of water per bird. Those
gallons carry off some rather unpleasant waste materials, commonly referred to
as “FOG” (fats, oils, and greases). Not surprisingly, publicly owned treatment
works don’t want FOG in their sewers, so poultry processors like Pilgrim’s Pride
Corp., based in Pittsburgh, TX, have spent years and millions of dollars in
dealing with the waste. But today, a new twist on an old process saves water and
turns the residual sludge from a cost center to a profit generator.
Saving water and dealing with
sludge is an ongoing task for Vernon Rowe, Corporate Environmental Manager for
Pilgrim’s Pride. He’s been in the industry more than 30 years and notes that
water isn’t a simple subject these days. “I’ve seen a lot of changes regarding
water, and things are more complicated with much more sensitivity to the cost
and the environment,” says Rowe.
All the more for a high-profile
corporation; Pilgrim’s Pride bills itself as the largest chicken company in the
US, with 37 plants and the capacity to process more than 45 million birds per
week, for a total of more than 9 billion pounds of poultry per year.
No More Trucking Away the
Sludge
The cost of treating sludge was
the overriding factor at Pilgrim’s Pride’s El Dorado, AR plant, but its
sensitivity to the environment played a role, as did the policies of the
company’s largest client—Wal-Mart (more about Wal-Mart’s role later). Before
upgrading their technology, Pilgrim’s Pride used a traditional Dissolved Air
Flotation (DAF) system, plus ferric sulfate, to treat the water used in cleaning
and processing poultry. The large volume of sludge left behind had to be trucked
away and land-applied as a fertilizer. “The volume of sludge that we generated
and the cost associated with it required us to search for alternatives to reduce
both the cost and the operation,” says Rowe.
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Photos: AWPI |
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In the processing plants, Pilgrim’s Pride’s five large-scale water
reuse systems use an ozone-based technology from AWPI. |
The search led Rowe to a new
approach in water treatment, Entrapped Air Floatation (EAF), a technology
offered by GE Water & Process Technologies. According to GE, EAF is designed
for food and beverage companies that dispose of fats, oils, and grease.
Preston Nelms, GE’s regional
account manager for Pilgrim’s Pride, says GE brought EAF to market in 2002, as a
high-performance alternative to conventional DAF technology, a method that
gained acceptance throughout the 1900’s across a wide variety of industrial
applications.
Whereas DAF uses pressurized gas
to separate solids and oil from a water stream, the EAF system foregoes
pressurized air in favor of air introduced under atmospheric conditions combined
with GE’s specialized polymers. The process entraps contaminants in air bubbles
for separation from the water.
“Our technology uses low pressure
and has many other technical differences,” says Nelms. “The machine is easier to
operate, and it has lower energy costs.”
Moreover, an initial audit of the
El Dorado plant showed that EAF could eliminate the use of ferric sulfate, a
chemical common for removing contaminants from wastewater, and also recycle the
high-quality effluent produced by the system for plant maintenance.
Such improvements fit well with
Pilgrim’s Pride’s ongoing search for opportunities and technologies to take
wastewater and reuse it for non-critical operations.
“Of course, we don’t use it for
the final wash on the birds, but there are many places where the FDA [Food and
Drug Administration] allows you to use recycled water,” says Rowe. “So we’re
always looking for opportunities in that area, and we have five large-scale
water reuse systems in our processing plants that use an ozone-based technology
from a company called American Water Purification Inc.” (See sidebar.) “We’re
always evaluating our plants and looking at what we pay for water and wastewater
treatment, and the technologies that recycle water in a cost-effective matter,”
he adds.
Onsite Pilot Program
For the pilot, GE brought a
50-gallon-per-minute EAF unit inside of a medium-sized enclosed trailer,
connected it to the plant’s waste and discharge, and ran side-by-side studies
against the existing treatment system.
“This enables GE and the customer
to grab samples and take them to a lab to validate performance,” Nelms explains.
“We can do the cost calculations on sludge and chemical cost savings and the
environmental benefits such as removing the fats, oils, and greases, chemical
oxygen demand, or whatever is on their permit so they don’t get charged for
it.”
“The pilot study ran for a couple
of weeks,” adds Rowe. “This is the ideal way to actually see what will happen,
because they test the chemical dosages and show what the real results and
benefits are going to be.”
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Photo: GE Water & Process
Technologies |
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GE provided Pilgrim’s Pride with its EAF technology. |
The tests confirmed what GE and
Rowe had expected, and construction followed, but wasn’t limited to just GE’s
new equipment. Rowe and Pilgrim’s Pride’s engineers saw an additional
opportunity to save on the plant’s energy usage by rethinking the flow of
effluents into GE’s system.
“We had a lot of pumps moving
water around to different places, and we eliminated most of them,” Rowe
explains. “In addition to the GE system we added new [filtration] screens and a
design that uses gravity flow. So instead of having about eight pumps moving the
water around, we narrowed it down to two pumps.”
The pumps were typically in the
range of 60 horsepower, so the reduction in electricity usage was substantial.
From Sludge to Animal
Feed
Reductions in sludge were equally
impressive—with the elimination of 286,000 gallons per year of ferric sulfate,
the amount of waste solids produced at El Dorado fell by 425,000 pounds per
week. Since the sludge wasn’t treated with ferric sulfate, it didn’t need to be
transported by truck for farmland application. According to Rowe, what once was
a costly waste solid, has become a valuable byproduct that is now processed at
Pilgrim’s Pride’s Farmerville, LA protein conversion plant. The final product is
a valuable protein source for poultry and animal feed.
Another bonus for the plant is the
reuse of roughly 30,000 gallons of water per day to wash down outdoor areas and
for non-contact cooling. Those gallons represent a significant factor.
“There are two things that drive
the chicken industry,” says Nelms. “First, they’re big water consumers, because
they generally use three to six gallons of water per day to process a bird. With
300,000 birds a day in the average plant, it’s very expensive. The second piece
is that it’s an industry with a lot of fats, oils, and greases, and that puts a
big load on the municipal water processor. Most of these facilities have to
pre-treat the water before it goes back to the municipality.”
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Photo: EAF |
The Entrapped Air Floatation system foregoes pressurized air in
favor of air introduced under atmospheric conditions combined with GE’s specialized
polymers. |
With many variables in the quality
of the wastewater in a food processing plant, Nelms stays in close contact with
the operators to help optimize the EAF performance.
The Wal-Mart Factor
Rowe looks at the relationship and
investment as a success, both economically and environmentally. Pilgrim’s Pride
maintains an ongoing water conservation awareness effort at every plant. At its
various locations, the company has implemented water reuse systems that conserve
more than 3,000,000 gallons of water daily. Such efforts fit well with the
company’s largest customer, Wal-Mart.
“They have a program that started
two years ago and an environmental sustainability policy that they handed down
to all their vendors and supply chain,” notes Rowe.
Wal-Mart’s program addresses all
aspects of sustainability, from packaging and wastewater to energy logistics,
transportation, and many other areas.
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Photo: EAF |
An initial audit of the El Dorado plant showed that EAF could
eliminate the use of ferric sulfate, and also recycle the high-quality effluent produced by the system for
plant maintenance. |
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Photo: GE Water & Process Technologies |
| GE plans to continue its efforts in the poultry industry,
expanding into other areas. |
Lessons Learned
All told, Rowe sees benefits from
the technology for similar industries, and with the experience gained from this
project. “The most important thing in using this type of process is to truly
understand the characteristics of the wastewater that’s being treated,” Rowe
says. “You need to consider the flow, the composition of the wastewater, your
treatment options, and your objectives. When you know that, you can look at the
various choices and make the most reasonable cost-effective decision.
“People think that one solution
would fit every poultry plant, but that’s not the case,” he adds. “They all have
different equipment, flow, and water chemistry, and some locations might have
more stringent treatment requirements.”
As for GE, the company honored
Pilgrim’s Pride with a 2008 ecomagination leadership award, for achieving
reductions in greenhouse gas emissions, waste solids, and water usage at the El
Dorado plant. The ecomagination award also honors the company for achieving
nearly $500,000 in annual operational savings.
With that kind of testimonial from
Pilgrim’s Pride, GE plans to continue its efforts in the poultry industry, and
expand into other areas.
“Poultry is a focus industry for
us, because they have a lot of plants, and they all use some sort of air
flotation technology,” says Nelms. “The replacement market is very large,
because a lot of these units are not stainless steel and have to be replaced
after 10 to 15 years.”
More Water Reuse
Opportunities
With Pilgrim’s Pride’s policy of
evaluating its plants and the cost of water and wastewater treatment, GE has
another role for the EAF technology, as a pretreatment for an advanced membrane
bioreactor system for water reuse. An onsite membrane bioreactor system could
ultimately provide a site, such as Pilgrim’s Pride, with the capability to fully
treat wastewater and remove organics and nutrients. Ultra filtration membranes
would then return the tertiary quality effluent for other non-potable
applications.
Such
a system has the potential to significantly reduce the discharge of any water to
the sewer. Thus, a plant like El Dorado would further improve its economics by
reusing more of the water required for its operations.