A superfiltration manufacturer has a membrane technology that can clean challenging protein processing wastewater. What’s prevented the use of this technology is the absence of an upstream filter to pull the solids out first and keep the membrane alive. In an 8-week pilot at a poultry harvesting plant, VelRay X did the upstream job, and the full system returned 97% of the plant's wastewater for reuse.
 

 

What protein processing plants pay for today

 

A poultry plant runs on water, and most of its effluent leaves carrying solids, fats, oils and grease (FOG). That water hits the budget in four places:

 

• Water that can’t be reused. Intake for production is high and expensive. Every gallon that goes to drain is a gallon that must be bought again, and that also affects a sustainability target that gets harder to hit.

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• Surcharges. Effluent limits keep tightening, and municipalities bill for every point of BOD, TSS and FOG over the line.

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• DAF system. Requires polymers and coagulants on order. Concentrate must be shipped out on a truck. Upsets stop production without warning, and a crew must clear them by hand.

 

• Skimmings worth less every year. DAF chemicals cut what renderers will pay for them, and forever-chemical rules limit where they can be land-applied.

 

Why membranes have stayed out of protein processing

 

Membrane technology can create the effluent quality protein plants need. The problem is they don’t last. In protein wastewater, conventional membranes foul past the point of recovery; FOG-laden water requires more cleanings, more chemicals, early replacement, and more downtime. Most can't tolerate FOG at all.

 

ZwitterCo, a global leader in membrane solutions, built a superfiltration system that can handle protein wastewater. That left one challenge: suspended solids still had to come out before the water reached the membranes, and no tradition upstream solution could do that in water this greasy.

 

The plant: doubling the flow, with no room to build

 

ZwitterCo’s customer, a poultry harvesting facility, was expanding. Wastewater flow was about to double, to 750,000 gallons per day.

 

Its treatment train ran feather and meat screens, a secondary screen and an air-only DAF. That setup was already costing money: DAF effluent drew surcharges, system upsets caused unplanned production downtime, and the DAF ran on purchased chemicals whose concentrate had to be hauled off.

 

Building a second treatment train using standard equipment (equalization tank and a DAF) would require the construction of a new building to house it. That meant the same problems at twice the volume.

 

The pilot

 

ZwitterCo ran a VelRay X system through an 8-week onsite pilot on five separate waste streams: primary screen effluent, meat screen effluent, DAF effluent, the inside-outside bird washer and the dip tank. The system treated all five.

 

VelRay X took the place of the air-only DAF, between the secondary screen and the superfiltration skid. It removed suspended solids from water that carried high levels of FOG, which is exactly the feed it was built to handle.

 

Results

 

On total plant wastewater, the pilot system recovered 97% of the water for reuse at an operating cost under one cent per gallon. TSS fell 98% and FOG dropped below detection.