Removal of Biological Oxygen Demand and Metal Ions in Dairy Processing Wastewater

The Shamrock Farms processing facility produces 500,000 gallons of wastewater a day with levels of biological oxygen demand, chemical oxygen demand, total suspended solids, and metal ions that exceed allowable limits. The goal of this project is to reduce these levels to meet EPA specifications. The system design uses an anaerobic membrane bioreactor to reduce biological oxygen demand, chemical oxygen demand, and total suspended solids. The bioreactor produces methane that is captured and stored for further use within the facility; cell mass sludge that is separated, dewatered and sent to a municipal digesting facility; and a permeate stream that undergoes electrodialysis to remove metal ions, producing a brine to be processed by an evaporation unit, and a permeate to be treated with ultraviolet light to eliminate remaining biologicals. Processed permeate water can then be reintroduced into the facility.