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

• Published in: Water science and technology 2007-01, Vol.55 (7), p.203-210
• Main Authors: Nakagawa, G, Ebie, Y, Tsuneda, S, Matsumura, M, Inamori, Y
• Format: Article
• Language: English
• Subjects: Aerobiosis; Ammonia; Ammonia - metabolism; Bacteria; Biodegradation, Environmental; Colony Count, Microbial; Denitrification; DNA; Domestic wastewater; Dynamics; Effluent standards; Effluents; equipment design; equipment performance; Genes, Bacterial; households; Japan; microbial genetics; nitrites; Nitrogen; Nitrogen - isolation & purification; Nitrogen removal; Nitrosomonas - genetics; Nitrosomonas - isolation & purification; Nucleotide sequence; Oxidation; Oxidation-Reduction; PCR; polymerase chain reaction; population dynamics; Populations; Real time; Removal; Reverse Transcriptase Polymerase Chain Reaction; Systems design; Temperature; Wastewater; Wastewater treatment; Water Purification
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2007.146

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.