Is nitrification the only cause of microbiologically induced chloramine decay?. (1st January 2016)

• Record Type: Journal Article
• Authors: Sawade, Emma; Monis, Paul; Cook, David; Drikas, Mary
• Is Part Of: Water research. Volume 88(2016)
• Page Start: 904
• Page End: 911
• Publication Date: 2016-01-01
• Subjects: Ammonia -- Ammonia oxidising bacteria (AOB) -- Chloramine decay -- Microbial decay factor -- Flow cytometry -- Nitrification; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2015.11.016
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Ammonia degradation was investigated in three batch reactors with differing initial concentrations of bacteria present in the same filtered water source based on pre-treatment filtration techniques. The potential for the bacterial community to degrade the ammonia present was determined in the absence of monochloramine, simulating a distribution system where a loss of disinfectant residual has occurred. Nitrification was observed in only one of the three batch reactors, whereas rapid microbiologically induced chloramine decay was present in two reactors. Results suggest that the microbial decay factor is not a valid tool for indication of nitrification, but may be used as an indicator of the occurrence of rapid monochloramine decay. Intact bacterial cell numbers did not to correlate with changes in ammonia, nitrite or nitrate concentrations and hence did not correlate with the nitrification observed. Neither use of the microbial decay factor or monitoring of ammonia oxidising prokaryotes provided an early indication for the occurrence of nitrification. Hence, monitoring of ammonia and nitrite would still be the most suitable tool for indicating nitrification. Highlights: Bacteria present in WTP filtered water can cause rapid monochloramine decay. Microbial decay factor is not a suitable tool for indication of nitrification. Intact bacterial cell numbers do not correlate to nitrification. Monitoring ammonia and nitrite provides the best indication of nitrification.