Study on Affecting Factors of Zeolite Biological Aerated Filter (ZBAF) in Micro-polluted Raw Water Treatment

The removal of CODMn, NH4+-N from micro-polluted raw water were investigated by zeolite biological aerated filter process. Several selected test factors such as media height ofBAF£¬hydraulic retention time(HRT)£¬the air/water ratio and concentration of NH4+-N in raw water were studied in the article. The test Results showed that the removal rate of pollutants from the micro-polluted raw water would improve with the increase of media height at the hydraulic retention time of 30min and the air/water ratio of 1:1. CODMn¡¢UV254¡¢turbidity were removed mostly at the foremost height of440mm, and NH4+-N was removed mostly at the height of220~440mm. The average removal rates of CODMn were36.81%, 33.17% and 26.29% respectively at the hydraulic retention time of 15min, 30min and 60min respectively, air/water ratio of 1:1. When the hydraulic retention time is30min, 28.24% of CODMn and 90.57% of NH4+-N were removed at the air/water ratio of 0.5:1, and 31.20% of CODMn and 93.22% of NH4+-N were removed at the air/water ratio of1:1. When the air/water ratio was 2:1, the average removal rates of CODMn and NH4+-N were hardly improved. The appropriate hydraulic retention time and air/water ratio of ZBAF to treat micro-polluted raw Water were 30min and 1:1respectively.