The project was initiated when it was determined that the spray irrigation system at Keystone Foods, a poultry processing plant, was severely undersized by the original design firm. The lack of available land for expansion and a citizen lawsuit against the original company prompted some innovative wastewater upgrade solutions to keep the plant and its approximately 2,000 jobs in a rural county from closing. As a result of the lawsuit settlement, it was agreed to provide wastewater polishing utilizing a 53-acre constructed wetland capable of producing tertiary wastewater. In addition, it was necessary to develop an innovative way to further polish and discharge the wastewater.
The stream available for NPDES permitting was too small and flow was intermittent, thus requiring alternative permitting and discharge strategies. McFadden Engineering was responsible for this task. Our solution was to permit the facility under the Underground Injection Control (UIC) program administered by the Alabama Department of Environmental Management (ADEM). Therefore, a 2 MGD UIC permit was obtained from ADEM (one of the largest UIC permits issued in Alabama), allowing the company to remain operational.
Tasks associated with the permit application included developing a calibrated and verified water quality model of the receiving stream utilizing the following field data:
From the data collected, a model was developed using the EPA WASP v6 water quality and flow model. Using the calibrated and verified WQ model, a waste-load allocation was developed to support discharge limits in the NPDES permit. Additional efforts by McFadden Engineering were to design the rapid infiltration beds (RIBS) for the wetland discharge and an innovative discharge header adjacent to the stream allowing the plant discharge to, in effect, provide groundwater recharge of the intermittent stream with stream quality water. Design considerations for the RIBS were sizing the system for average and peak flows, infiltration pipe design, bed material specification and connection to the stream header manifold.
In summary, this project demonstrates McFadden Engineering’s capability to design innovative and alternative solutions to major wastewater facilities and the associated permitting requirements by state and federal agencies while maintaining an environmentally-friendly facility.