Abstract
In this study, the abundance and sequences of the amoA gene in ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) were defined in three wastewater treatment plants using activated sludge with biological nitrogen removal in different countries: Thailand, United States of America (USA), and Japan. Quantitative real-time polymerase chain reaction (PCR) and PCR coupled with denaturing gradient gel electrophoresis were used to find the comparative abundance and identity of AOB and AOA. The conditions at the Phuket WWTP in Thailand promoted the dominance of AOA amoA genes over AOB amoA genes, while conditions at the WWTPs in Japan and USA promoted growth of AOB. Three parameters that may have contributed to the AOA dominance in Phuket were longer SRT, higher temperature, and higher pH. The Phuket WWTP is a unique system that can be used to better understand the conditions that promote AOA growth and dominance over AOB. In addition, analysis of operational data in conjunction with AOA and AOB community structure from the Phuket WWTP may elucidate advantages of AOA in meeting stricter treatment standards.
Acknowledgments
The authors thank Ms. Nimaradee Boonapatcharoen, Ms. Maneerat Khemkhao, and Ms. Chompoonut Auphimai from King Mongkut's University of Technology Thonburi (KMUTT), Ms. Areerat Kunanopparat, and Ms. Supaporn Phanwilai from Kasetsart University for supporting this research.
Funding
The authors thank the Kasetsart University Research and Development Institute (KURDI), Faculty of Engineering, Kasetsart University, Bangkok, Thailand, and Faculty of Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan, for grants that supported this research.