title: Influence of operational parameters on nitrogen removal efficiency and microbial communities in a full-scale activated sludge process.
abstract: 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.
authors.affiliation: Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Young Mo
authors.initials: YM
authors.lastname: Kim
authors.forename: Hyun Uk
authors.initials: HU
authors.lastname: Cho
authors.forename: Dae Sung
authors.initials: DS
authors.lastname: Lee
authors.forename: Donghee
authors.initials: D
authors.lastname: Park
authors.forename: Jong Moon
authors.initials: JM
authors.lastname: Park
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D002244:Carbon / Q000032:analysis; D058440:Denitrification / Q000235:genetics; D007220:Industrial Waste / Q000032:analysis; D058465:Nitrification / Q000235:genetics; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000379:methods*
chemical_list: D007220:Industrial Waste; D009573:Nitrites; D012722:Sewage; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen