Influence of operational parameters on nitrogen removal efficiency and microbial communities in a full-scale activated sludge process

• Published in: Water research (Oxford) Vol. 45; no. 17; pp. 5785 - 5795
• Main Authors: Kim, Young Mo, Cho, Hyun Uk, Lee, Dae Sung, Park, Donghee, Park, Jong Moon
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2011; Elsevier
• Subjects: Activated sludge; Activated sludge process; ammonia; Ammonia - metabolism; Applied sciences; Bacteria; Bacteria - genetics; Bacteria - metabolism; Biodegradation, Environmental; Biological Oxygen Demand Analysis; biomass; Carbon - analysis; Communities; community structure; Denitrification - genetics; Denitrifying bacteria; Exact sciences and technology; Genes; Industrial Waste - analysis; microbial communities; Microorganisms; nitrates; Nitrification; Nitrification - genetics; Nitrifying bacteria; Nitrites - metabolism; Nitrobacter; nitrogen; Nitrogen - isolation & purification; nitrogen content; Nitrogen removal; Nitrosomonas; Nitrosomonas europaea; Nitrosomonas nitrosa; Nitrospira; Operational parameter; Oxidation-Reduction; phenol; Pollution; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Populations; qPCR; quantitative polymerase chain reaction; recycling; Sewage - microbiology; Tanks; Waste Disposal, Fluid; wastewater; Water Purification - methods; Water treatment and pollution; Nitrogen removal; Activated sludge; Denitrifying bacteria; qPCR; Nitrifying bacteria; Operational parameter; Nitrites; Nitrogen compounds; Nitrates; Biomass; Retention time; Biological purification; Bacteria; Recycling; Microbial community; Organic compounds; Nitrogen; Real time system; Operating conditions; Polymerase chain reaction; Ammonia; Industrial waste water; Nitrification; Phenols; Poison; Waste water purification
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2011.08.063

To improve the efficiency of total nitrogen (TN) removal, solid retention time (SRT) and internal recycling ratio controls were selected as operating parameters in a full-scale activated sludge process treating high strength industrial wastewater. Increased biomass concentration via SRT control enhanced TN removal. Also, decreasing the internal recycling ratio restored the nitrification process, which had been inhibited by phenol shock loading. Therefore, physiological alteration of the bacterial populations by application of specific operational strategies may stabilize the activated sludge process. Additionally, two dominant ammonia oxidizing bacteria (AOB) populations, Nitrosomonas europaea and Nitrosomonas nitrosa, were observed in all samples with no change in the community composition of AOB. In a nitrification tank, it was observed that the Nitrobacter populations consistently exceeded those of the Nitrospira within the nitrite oxidizing bacteria (NOB) community. Through using quantitative real-time PCR (qPCR), nirS, the nitrite reducing functional gene, was observed to predominate in the activated sludge of an anoxic tank, whereas there was the least amount of the narG gene, the nitrate reducing functional gene. ► SRT and internal recycling ratio were controlled to improve TN removal efficiency in a full-scale process. ► Increased biomass concentration via SRT control enhanced TN removal. ► Decreasing the internal recycling ratio restored nitrifier's activity which had been inhibited by phenol. ► Application of specific operational strategies could change the physiological state of the bacterial populations. ► Proper operational strategies should be tailored to accommodate specific circumstances.