Kinetic characteristic of single biological aerated filter (BAF) for domestic wastewater treatment

The kinetic models of organics and ammonia removal in a biological aerated filter (BAF) for domestic wastewater treatment were established. The kinetic constants k1 of reactor UBAF-A, UBAF-B and UBAF-C were 15214, 17422 and 16372 respectively under the operational conditions of temperature 20-225°C and HRT125h. The results showed that organic removal efficiency was affected by the filter media. The gravel media filter has a better performance than that of ceramic media, and the small size media filter has a better performance than the large one. The kinetic characteristics of ammonia removal in BAF were analyzed. The results demonstrated that the ammonia removal rate changed with the activity distribution of ammonia oxidizer in a single BAF, which was affected by stratum concentration, DO and pH value. The three parameters changed along the water flow and the nitrification rate to remove organics and ammonia changed in three different kinetic regions in the reactor dimension, that is DO, double matrices and substratum control. There were different characteristics of nitrification rate in the three kinetic regions.