Abstract: Coal ash was used as the main material to produce the ceramsite filter medium of biological aerated filter. It was used as bio-film carrier of biological reactor to treat municipal domestic sewage. During the reactor operation, the average removal rate of COD and nitride ammonium were 85.31% and 66.95% respectively. At a HRT of 1.25h and an air/water ratio of 4.0, the removal rate of COD was the highest, reaching 95.02%; and at a HRT of 1.5h, an air/water ratio of 2.0 and a pH of 8~9, the removal rate of nitride ammonium was the highest, reaching 79.02%. After 12 h backwashing, the removal rates of both COD and nitride ammonium returned to normal.

Key words: Coal-ash, Filter medium, Biological reactor, COD, Nitride ammonium