title: Use of real-time PCR to examine the relationship between ammonia oxidizing bacterial populations and nitrogen removal efficiency in a small decentralized treatment system 'Johkasou'.
abstract: The aim of this study was to examine the relationship between ammonia oxidizing bacterial populations and biological nitrogen removal in a small on-site domestic wastewater treatment system "Johkasou". The population dynamics of ammonia oxidizing bacteria (AOB) in six full-scale advanced Johkasous was surveyed using real-time PCR assay over a period of one year. These Johkasous were selected to compare the AOB populations in different treatment performance. When the effluent NH4-N concentration was higher than 2 mg L(-1), it was difficult to meet the effluent standard of advanced Johkasous (T-N 10 mg L(-1)). In contrast, the nitrogen removal efficiency was hardly affected by nitrite oxidation and denitrification in these systems. In other words, ammonia oxidation was a rate-limiting step. Furthermore, we focused on the relationship between NH4-N loading per AOB cell and nitrogen removal. Real time PCR monitoring results demonstrated that it is important to regulate NH4-N loading per AOB cell below 210 pg cell(-1) day(-1) to meet the effluent standard of advanced Johkasou. It is considered that NH4-N loading per AOB cell is a useful parameter for determining suitable nitrogen loading and small decentralized system design.
authors.affiliation: Graduate school of Life and environmental science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan. nakagawa.gou@nies.go.jp
authors.forename: G
authors.initials: G
authors.lastname: Nakagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Ebie
authors.forename: S
authors.initials: S
authors.lastname: Tsuneda
authors.forename: M
authors.initials: M
authors.lastname: Matsumura
authors.forename: Y
authors.initials: Y
authors.lastname: Inamori
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism*; D001673:Biodegradation, Environmental; D015169:Colony Count, Microbial; D005798:Genes, Bacterial; D007564:Japan; D009584:Nitrogen / Q000302:isolation & purification*; D009606:Nitrosomonas / Q000235:genetics* / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D018508:Water Purification
chemical_list: D000641:Ammonia; D009584:Nitrogen