抄録
An anaerobic fluidized bed (AFB) bioreactor followed by an aerobic bioprocess enables effectively simultaneous removal of suspended solids, organic matter, phosphorus and nitrogen compounds. In the AFB bioreactor, suspended solids, colloidal matter and phosphorus were coagulated with the combined use of small amount of polymerized aluminium chloride and weakly anionic polymers to generate large sized coagulated sludge which could rapidly separate from the liquid. Especially, in the summer season with high water temperature, the pelletized sludge with high effective density can be produced. The microscopic observation showed the pelletization of sewage pollutants was caused by chemical coagulation as well as bacterial growth. Above 18°C of temperature, recycling of nitrified effluent from the aerobic bioprocess to the AFBbioreactor achieved complete denitrificationandnitrificationwitha total retention time of 4h (2h in AFB bioreactor and 2h in the aerobic bioprocess) and a recirculation rate 3 times the feed rate, resulting in above 80% of total nitrogen removal efficiency.
