Removal of organic matter and nitrogen from distillery wastewater by a combination of methane fermentation and denitrification/nitrification processes

摘要

The distillery wastewater of Guangdong Jiujiang Distillery, which is c haracteristic of containing high organic matters and rich total nitrogen, was tr eated by a combination of methane fermentation and denitrification/nitrification processes. 80% of COD in the raw wastewater was removed by methane fermentation at the COD volumetric loading rate of 20 kg COD/(m3·d) using the expanded gra nule sludge bed (EGSB) process. However, almost all the organic nitrogen in the raw wastewater was converted into ammonia by ammonification there. Ammonia and v olatile fatty acids (VFA) remaining in the anaerobically treated wastewater were simultaneously removed utilizing VFA as an electron donor by denitrification oc curring in the other EGSB reactor and nitrification using PEG-immobilized nitrif ying bacteria with recirculation process. An aerobic biological contact oxidizat ion reactor was designed between denitrification/nitrification reactor for furth er COD removal. With the above treatment system, 18000—28000 mg/L of COD in raw wastewater was reduced to less than 100 mg/L. Also, ammonia in the effluent of the system was not detected and the system had a high removal rate for 900—1200 mg/L of TN in the raw wastewater, only leaving 400 mg/L of nitrate nitrogen.