Nitrifying and Denitrifying Microbial Communities in Centralized and Decentralized Biological Nitrogen Removing Wastewater Treatment Systems

• Main Authors: Sara K. Wigginton, Elizabeth Q. Brannon, Patrick J. Kearns, Brittany V. Lancellotti, Alissa Cox, Serena Moseman-Valtierra, George W. Loomis, Jose A. Amador
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Water
• Subjects: wastewater; wastewater treatment plant; onsite wastewater treatment system; biological nitrogen removal
• Online Access: https://www.mdpi.com/2073-4441/12/6/1688

Biological nitrogen removal (BNR) in centralized and decentralized wastewater treatment systems is assumed to be driven by the same microbial processes and to have communities with a similar composition and structure. There is, however, little information to support these assumptions, which may impact the effectiveness of decentralized systems. We used high-throughput sequencing to compare the structure and composition of the nitrifying and denitrifying bacterial communities of nine onsite wastewater treatment systems (OWTS) and one wastewater treatment plant (WTP) by targeting the genes coding for ammonia monooxygenase (<i>amoA</i>) and nitrous oxide reductase (<i>nosZ</i>). The <i>amoA</i> diversity was similar between the WTP and OWTS, but <i>nosZ</i> diversity was generally higher for the WTP. Beta diversity analyses showed the WTP and OWTS promoted distinct <i>amoA</i> and <i>nosZ</i> communities, although there is a core group of N-transforming bacteria common across scales of BNR treatment. Our results suggest that advanced N-removal OWTS have microbial communities that are sufficiently distinct from those of WTP with BNR, which may warrant different management approaches.