Quantitative analyses of the composition and abundance of ammonia-oxidizing archaea and ammonia-oxidizing bacteria in eight full-scale biological wastewater treatment plants

This study investigated the diversity and abundance of AOA and AOB amoA genes in eight full-scale wastewater treatment plants (WWTPs). Although the process principles and system operations of the eight WWTPs were different, quantitative real-time PCR measurements showed that AOB amoA genes outnumbered AOA amoA genes with the ratio varying from 2.56 to 2.41 × 103, and ammonia may be partially oxidized by AOA. Phylogenetic analyses based on cloning and sequencing showed that Nitrososphaera cluster was the most dominant AOA species and might be distributed worldwide, and Nitrosopumilis cluster was few. Statistical analysis indicated that there might be versatile AOA ecotypes and some AOA might be not obligate autotrophic. The Nitrosomonas europaea cluster and Nitrosomonas oligotropha cluster were the two most dominant AOB species, and AOB species showed higher diversity than AOA species.