Biological nutrient and organic removal from meat packing wastewater with a unique sequence of suspended growth and fixed-film reactors

摘要

A unique sequence of anaerobic filter/suspended anaerobic/aerobic (AO) reactor/aerobic filternsystem was developed to alleviate the drawbacks of conventional suspended growth and fixedngrowth systems. An anaerobic filter (AF) was used to efficiently produce volatile fatty acids (VFAs)nprior to the aerobic suspended growth. A second anaerobic reactor was installed in the A/Onreturn activated sludge line to improve phosphorus uptake by potentially controlling glycogennaccumulating organisms (GAOs). One biological aerobic filter (BAF) was used for nitrificationnfollowed by an anoxic filter for denitrification and a second BAF was used for effluent polishing.nThe meat packing wastewater had a biochemical oxygen demand (BOD) of 853mg/L and totalnnitrogen (T-N) and total phosphorus (T-P) concentrations of 61.1mg/L and 5.8mg/L, respectively.nThe BOD removal efficiency was 99.0–99.7% and the suspended solids (SS) concentration innthe effluent was below 10mg/L. The T-N removal efficiency was maintained at greater than 75.0%nexcept at low C/N ratios. A high T-P removal efficiency, 74.7–83.9%, was also obtained whennthe system was operated at a hydraulic retention time of 15.7 hrs. The AF successfully producednVFAs that aided in phosphorus removal. Additionally, recycled concrete aggregate used asnattachment media in the biological filters continuously provided micronutrients and