| As a new wastewater treatment technology, biological aerated filter is widely used both at home and abroad. Biological aerated filter has many advantages of high efficiency, small space requirement, low capital and operating cost, simplify management and capacity of anti impact load et al. In the removement of the organic materials, deammoniation, denitrification, dephosphorization and pre-treatment process of micro-contamination source water, biological aerated filter exits preferable foreground. This technological adapts to the current situation of capital scarcity and low level of technology in our country,s wastewater treatment projects. We should do research on its theory and technology, sum up state of the art in order to make it domestically produced and have application in practice.This paper experimental studied the removal performance of the domestic wastewater treatment with different fillers in BAFs and discussed the biofilm formation. The COD, NH3-N and turbidity removal effects among BAFs using activated carbon, mixed stuffing and rubble as stuffings were compared at the condition of different HRT, hydraulic loading, air-water ration, filling height, backwashing et al. The results show that:(1) BAF was easily to hang membrane and rapid start. The effects of biofilm culturing were less affected by types of fillers. Three fillers were chosen in experiment (activated carbon, mixed fillers, crushed filler) and the times of biofilm formation were 10d, 13d, 14d.(2) BAF had stronger capacity of resisting impact on load. When flactuating CODcr between 89.25mg/L to 313.5mg/L, the effluent quality reached 13.44-39.45 mg/L. It also had stronger nitrification performance and effluent ammonia nitrogen lower than 4 mg/L, turbidity value stability reached in 2-6NTU. All were lower than first class national standard (A).(3) The main factors to impact on removal performance were filler type, filler height, air-water ration, hydraulic loading and hydraulic retention time in BAF. When temperature reached 17-25℃, the best air-water ration of three fillers were 3:1 to 4:1. Under these conditions, the best removal performance was activated carbon, the CODcr, ammonia nitrogen removal rate reached 90.75% and 94.51%, effluent turbidity value down to 1.1NTU, but its cost was higher. Although the cost of crushed filler was very low, the removal performance of CODcr, ammonia nitrogen and turbidity was relatively low, count amount to requirements of"Integrated Wasterwater Discharge Standard". So considered from technology and economic, the best choice was mixed filers in three type fillers BAF.(4) Experiments showed that: During the stable operation period of BAF, the removal of organical compounds in water was improved by increasing the fillers height. But when filler exceeded more than 70cm high, the removal ration of organical compounds didn't improve too much. When the hydraulic loading of activated carbon and mixed fillers was between 1.5 and 3.5 (m~3/m~2.h), the ratio of remove was better and crushed filler was 1.5 to 3(m~3/m~2.h).(5) After backwashing of biological aerated filter, the treatment would be restored in a short time. By using mixed fillers as filler, the removal ration of CODcr would be restored to 84.78% in 4 hours and ammonia nitrogen to 82.96% in 3 hours.
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