Nitrifying treatment of wastewater from fertilizer production in a multiple airlift loop bioreactor

摘要

An 80 m~3 gas-liquid-solid three-phase flow multiple airlift loop bioreactor (ALR) with a low ratio of height to diameter s,in which biofilm replaced the activated sludge,was used in the nitrifying treatment of the effluent from Tengfei Chemical Fertilizer Plant,Tianjin,PR China.The influences of the ratio of bed (settled) volume to bioreactor volume V_b/V_R,superficial air velocity U_g,hydraulic residence time HRT and pH value on ammonia nitrogen reduction were investigated and discussed.The optimum operating conditions were obtained as pH value of 7.0-8.0,V_b/V_R of 0.65,U_g of 0.01 ms~(-1) and HRT of 6h were found.Under the optimum operating conditions,the effluent COD and NH_4-N were less than 50 and 10 mg 1~(-1),which was far below the primary discharge standard for chemical fertilizer industry of PR China:COD<100mgl~(-1) andNH_4-N<40mg l~(-1) (GWPB4-1999).