Domestic wastewater treatment using biological aerated filtration system with modified zeolite as biofilm support

Modified zeolite and natural clinoptilolite were applied to treat domestic wastewater in two two-stage up-flow biological aerated filters (BAF) to compare their abilities to act as biofilm supports. The results showed that the two-stage BAF with modified zeolite brought a relative superiority to natural clinoptilolite two-stage BAF in terms of chemical oxygen demand and ammonia nitrogen removal under the conditions of temperature 20-26 degrees C and dissolved oxygen above 4.00 mg l(-1). In addition, the detection of the amount of heterobacteria and nitrobacteria of two two-stage BAFs also showed that modified zeolite medium was more suitable to the attached growth of nitrobacteria, which is helpful to the improvement of nitrification performance in two-stage BAF with modified zeolite.