US poultry processor delivers on TMDL wastewater permit

Koch Foods, spurred byNPDES Total Maximum Daily Limits, won Clean Water Award by removing phosphorusfrom poultry wastewater.

View of processing plant from the primary sequencing batch reactor (SBR) operated in conjunction with the new DAF chemistries to provide phosphorus removal with additional pH control.
View of processing plant from the primary sequencing batch reactor (SBR) operated in conjunction with the new DAF chemistries to provide phosphorus removal with additional pH control. 

U.S. poultry processor Koch Foods faced challenging new wastewater discharge permit limits from the Environmental Protection Agency (EPA) at the broiler chicken processing facility in Gadsden, Alabama, but was spurred on to win the coveted Clean Water Award from U.S. Poultry & Egg Association (USPOULTRY) in 2014.

After earning a Clean Water Award honorable mention for direct-discharge poultry processors in 2013, managers at Koch’s broiler chicken processing facility in Gadsden faced a new challenge in meeting a tough new Total Maximum Daily Load (TMDL) phosphorus limit for the Coosa River, which is designated an "impaired stream" by EPA.

New poultry wastewater discharge limits from EPA for Coosa River

Koch Foods managers at the chicken processing facility had to come up with a plan in 2014 to meet new TMDLs of phosphorus under the National Pollution Discharge Elimination System (NPDES).
Permitted facilities undergo a renewal every five years. Those permitted limits have typically gotten tougher, particularly as streams impaired for a variety of contaminants found in SIC2015 facility effluents grow. Concurrently, TMDLs are being defined for those impaired streams.

In 2014, the Koch Foods Gadsden facility found itself in just that situation – an NPDES direct discharge facility that treats a high-strength wastewater from processing 410,000 broiler chickens per day faced a new TMDL phosphorus limit for the Coosa River. Phosphorus is one of the more challenging discharge limits to meet for any facility, whether industrial or publicly owned treatment works (POTW). In light of these challenges, the Gadsden facility environmental staff and management did something unusual . . . they won the 2014 USPOULTRY Clean Water Award outright.

Award-winning wastewater treatment processes

Koch Foods’ award-winning wastewater treatment process at the Gadsden poultry processing facility has evolved over the years since the broiler producer purchased the facility from Tyson Foods in 2007. The wastewater treatment system consisted of a dissolved air flotation (DAF) with anaerobic, storage and wasting lagoons, including basins for equalization and aeration. It was initially upgraded by covering the 10-million-gallon anaerobic lagoon in 2008. That was followed by replacing the aerobic basin with a new 3-million-gallon sequencing batch reactor and flow equalization basin that discharged water through ultraviolet light disinfection.
Koch Foods environmental staff knew the permit changes were pending during the 2013 Clean Water Award competition and had decided on a second DAF with chemical treatment after the sequencing batch reactor and flow equalization basin.

Jeff Seymore, Koch Foods environmental manager, noted that the Alabama Department of Environmental Management “based us on 1 million gallons per day with 8.34 pounds per day [of total phosphorus (TP) discharged]. It wasn’t on if your flows changed or if it was 1.6 million gallons and a major. We got a 1.0 mg/L average and a 1.5 max at 1.6 million gallons in the permit reclassification. And we are a major discharger."

Multiple treatments for poultry wastewater discharge

Even with that settled, it was no easy feat to meet the new permit that added the new low phosphorus TMDL for eight months and a more achievable previous limit for the remaining four months. The Koch Foods team's original strategy for DAF treatment with alum after the final flow equalization basin with seven days holding only achieved 3-4mgTP/L. They next tried a base feed of alum further upstream to an anaerobic lagoon but the results were inconsistent.

What worked was base feeding sodium aluminate into the sequencing batch reactor from a bulk tank, followed by the DAF with alum treatment and polymers. That combination has also allowed Seymore and his staff to eliminate the need for a pH control device. The months of effort have identified the adequate loading amounts needed to achieve a target phosphorus concentration in the final flow equalization basin.

The Koch Foods wastewater management team monitors the phosphorus concentrations leaving the plant and entering the flow equalization basin where Michael Dean, wastewater operations supervisor notes, “We keep it at 10mg/L but if it gets to 12 or 13 you are really pushing it.” The staff worked with the DAF manufacturer and decided on an alum mixing scheme more reminiscent of water treatment than poultry processing, e.g. flash mixing and flocculation tank, not flocculation tubes, yielding what appears to be the optimum reaction time sequence.

Additional DAF polished poultry wastewater discharge

Koch Foods runs the additional DAF system year round, albeit with less chemistry during the non-TMDL permitted months. Initially, the decision was made to simplify operations, ensure equipment continuously ran, and minimize potential upsets caused by unforeseen flow variations.

Seymore adds, “It has actually polished our water and made our water even better. In the flow equalization basin, we will have some algae at times. Putting the DAF in as a tertiary treatment and to primarily meet the phosphorus limits has improved out water quality.” Table 1 shows the improvements from the added DAF and operational treatment strategy.

Koch Foods addressing long-term sustainability

So while the phosphorus limit challenges are under control, the staff is addressing the long-term environmental sustainability of the facility. Water conservation and reuse efforts have yielded roughly 500,000 gallons per day returned to exterior locations. Currently, an active partnership with a manufacturer of an innovative, energy-efficient lagoon mixing and aeration system uses existing surface impoundments that are no longer part of the active treatment system to digest the biosolids.

All of the facility’s stormwater is captured and diverted to the old impaired flow equalization basin where the biosolids digestion studies are being conducted. The old waste lagoon holds DAF solids with long-term holding capacity. Since Koch Foods has operated the Gadsden facility, solids were removed only during the upgrade of the anaerobic lagoon. A portion of the anaerobic lagoon biogas is blended with purchased natural gas and burned in boilers. The facility is looking at not only equipment that would burn all of the biogas, but also convert it into biomethane that could be put back into the pipeline. Opportunities are also being considered for using biogas with its vehicular fleet.

Seymore notes that Koch Foods has other upgrades and new system installations under way at other facilities, using biological treatment approaches unlike those used in Gadsden. But regarding the Gadsden facility, Seymore happily notes, “We have worked with what our previous investments and designed it to be an advanced waste treatment system. And now with the DAF on the end of it, we have had no problems.”

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