Tuesday, November 6, 2007 - 11:00 AM
230-5
Water Quality Improvements of CAFO Wastewater after Advanced Treatment and Its Reuse Potential.
Matias Vanotti and Ariel Szogi. USDA-ARS, 2611 W. Lucas St., Florence, SC 29501
We conducted a study to determine the water quality improvements by an alternative on-farm waste treatment technology operating at full-scale during a 2-yr evaluation period. In addition, we evaluated water quality changes in the converted lagoon that were compared with an adjacent traditional lagoon with similar production management. The on-farm treatment system greatly increased the efficiency of liquid-solid separation by polymer injection to increase solids flocculation. Nitrogen management to reduce NH3 emissions was accomplished using nitrification/denitrification. Subsequent alkaline treatment of the wastewater in a P removal unit precipitated P and produced a disinfected liquid effluent. The on-farm system removed 98% of the suspended solids, 100% of the BOD, 98% of the ammonia, 95% of the total phosphorus (TP), 99% of the copper and 51% of the salinity. These high treatment efficiencies were obtained consistently under cold and warm weather conditions with varying strength of the liquid manure (COD = 2,000 to 45,000 mg L-1, TKN = 370 to 3,100 mg L-1, TP = 70 to 1,310 mg L-1) from typical livestock growth cycles. As the treatment system cleansed the raw liquid manure and replaced the anaerobic lagoon liquid with clean water, it transformed the anaerobic lagoon into a treated water aerobic pond. By the second year, the following reductions in water constituents were realized: 73% of suspended solids, 77% of the BOD, 92% of the ammonia, 38% of the TP, 37% of the zinc, 39% of the copper, and 55% of the salinity. These reductions showed an additional environmental benefit obtained when advanced treatment technology is retrofitted to a swine operation with an existing anaerobic lagoon; that is, the clean up of the lagoon liquid without additional cost to the farmer. These findings overall showed that cleaner alternative technologies can have significant positive impacts on the environment and the livestock industry.