Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters.The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nit...Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters.The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination.The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors(RAB)with different chlorine to ammonia ratios and total organic carbon(TOC)levels.The results indicated that nitrification occurred despite at a low influent concentration of ammonia,and a high concentration of nitrite nitrogen was detected in the effluent.The study illustrated that reactors 1(R1)and 3(R3),with higher TOC levels,produced more nitrite nitrogen,which was consistent with the ammonia-oxidizing bacteria(AOB)counts,and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts(R2 and R4).The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification.Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors.The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification.Bulk water with a high TOC level supported the occurrence of nitrification,and AOB development occurred at all examined chlorine to ammonia dose ratios(3:1 or 5:1).展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant No.50878164)the Key Special Program on the Science&Technology for the Pollution Control and Treatment of Water Bodies(Grant No.2008ZX07422-005)the Foundation of Key Laboratory of Yangtze River Water Environment,Ministry of Education(Tongji University),China(Grant No.YRWEY1001).
文摘Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters.The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination.The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors(RAB)with different chlorine to ammonia ratios and total organic carbon(TOC)levels.The results indicated that nitrification occurred despite at a low influent concentration of ammonia,and a high concentration of nitrite nitrogen was detected in the effluent.The study illustrated that reactors 1(R1)and 3(R3),with higher TOC levels,produced more nitrite nitrogen,which was consistent with the ammonia-oxidizing bacteria(AOB)counts,and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts(R2 and R4).The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification.Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors.The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification.Bulk water with a high TOC level supported the occurrence of nitrification,and AOB development occurred at all examined chlorine to ammonia dose ratios(3:1 or 5:1).
