Attapulgite suspension filter material for biological aerated filter to remove CODMn and ammonia nitrogen in micropolluted drinking water source

An attapulgite suspended (AS) filter material was successfully prepared and used in combination with biological aerated filter (BAF) to pretreat excess organic matter and ammonia nitrogen in micropolluted water. The AS filter material was of low density and floated on the water surface, which is beneficial to optimize the hydraulic conditions. Through scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) It was found that the surface of the filter material was uneven, the pores were deep. When the hydraulic load is 4 m/h and the gas to water volume ratio is 2:1, the removal rates of permanganate index (CODMn) and ammonia nitrogen by ASBAF are up to 57.49 and 88.11%, respectively, and the effluent quality meets relevant standards. After backwashing, the pollutants removal rate will return to stable filtration after two hours. A short-term shutdown of the reactor has little effect on the processing performance of ASBAF, but a long-term shutdown will greatly affect the removal rate of CODMn. The complete organic matter degradation model can well fit the experimental effluent water quality.