Simultaneous removal of nitrogen and THM precursor by developed submerged biofilm process for drinking water

Reciprocating motion submerged biofilm process (RMSBP) was developed for nitrogen, biodegradable carbon and trihalomethane(THM) precursor simultaneous removal as a pre-treatment of polluted raw water for drinking water supply. The focus of this study is to get a stable treatment water through four seasons under no pre-sedimentation systems. All experiments were done at the lake side, and raw water was introduced from the lake continually. There is no sedimentation tank in the reactors and biofilm carrier clogging dose not occur and biofilm growth is uniform through the whole reactors by reciprocating motion carrier. RMSBP was able to decrease NH₄-N, and NO₂-N and NO₃-N simultaneously under unaerated conditions. Decrease of nonpurgeable DOC and ultraviolet (UV) absorbance (1 cm path length, pH7.0, 260nm) is possible almost two to ten times more expensive than the traditional biological filtration process. Nitrification, denitrification, biodegradable carbon and THM precursor removal was stably achieved simultaneously from autumn to spring when water temperature is low.