THE BIOGEOCHEMICAL IMPACT OF EFFLUENT FROM A POULTRY PROCESSING FACILITY ON A SMALL HEADWATER STREAM, GREENVILLE, SOUTH CAROLINA

Poultry processing produces sizable amounts of wastewater through the cleaning, washing, and disinfection processes. The effluent generated can typically have elevated levels of nutrients, including nitrogen and phosphorus, from the chicken waste as well as elevated levels of cleaning agents like chloride used in the disinfection process. The discharge of this effluent into local waterways can bring about marked changes to stream water chemistry.

This study quantifies the impacts of effluent discharge from a poultry processing facility has on the chemical composition of a small headwater stream in Greenville, South Carolina. Effluent from the plant empties into the stream via a discharge pipe and associated gully each weekday evening. Sampling sites were established 115 meters above and below the point of discharge. A pressure transducer took continuous stage measurements, and an YSI sonde took continuous conductivity readings at the downstream site. Automated ISCO water samplers were placed at both sites and collected water samples during discharge events. The samples were analyzed in the lab for pH, conductivity, and concentrations of major cations and anions, ammonium, dissolved organic carbon, and dissolved oxygen.

Although the volume of the effluent discharge is small with minimal change in the stage height relative to the upstream site, the release does produce a readily discernable effluent pulse which rapidly alters the local stream water chemistry for upwards of two hours. Following discharge events conductivity more than doubled and concentrations of ammonium (~12 mg/L), phosphate (~6 mg/L), nitrite (~1.5 mg/L), sodium (~19 mg/L), chloride (~22 mg/L), potassium (~18 mg/L), and dissolved organic carbon (~29 mg/L) increased dramatically relative to background concentrations. The effluent pulse resulted in rapid declines in dissolved oxygen, routinely changing the stream from well oxygenated (8-12 mg/L) to hypoxic (2.5 mg/L) in a half hour period. Discharge of effluent provides an episodic pulse of nutrients to the stream, which should have downstream impacts on the stream ecosystem and biogeochemical processes.