Mechanism research of the fly ash aerated concrete packing biological membrane surface by the operating effect of BAF

This paper focuses on the analysis of fly-ash aerated concrete particles applied into BAF. The comparative analysis of the removal rates of COD and NH₃-N during the period of start-up period demonstrates the superiority of organic removing bacteria in biological film on the packing materials surface in the initial stage of start-up. Under the condition of the operation of BAF in different gas-water ratio, hydraulic loading rate and organic load, the comparative analysis of the removal rate of COD andNH₃-N concludes that nitrobacterium becomes the main ingredient of biological film after gradually grows mature and surpasses organic removing bacteria during the period of the operation of BAF, concluding that the biological film of nitrobacterium is easily to be attached to the surface of fly-ash aerated concrete particles.