Understanding the degradation of dissolved organic matter (DOM) is vital for optimizing DOM control. However, the microbially mediated utilization and transformation of DOM in wastewater treatment plants remain poorly characterized. Here, microbes and the fate of DOM in full-scale anaerobic-anoxic-aerobic (A/A/O) and anaerobic-aerobic (A/O) processes were characterized using high-resolution mass spectrometry and genome-resolved metagenomics. Findings show distinct molecular compositions of effluent DOM between different processes, with more lignin- and tannins-like substances in A/O while more condensed aromatics-like compounds in A/A/O. In conjunction with the comparisons between A/A/O and A/O microbiomes, the properties (e.g., biodegradability) and compositions of DOM were found highly correlated to microbes. Furthermore, co-occurrence network analysis demonstrated that bacteria in different functional guilds showed different associations to specific DOM. Module hubs representing the keystone species in each functional guild were mainly affiliated with Bacteroidota, Chloroflexota, and Actinobacteriota. They were generalists in DOM transformation and responsible for the increased humification in the effluent. In contrast, microbial connectors were dominated by Gammaproteobacteria, Myxococcota, and Acidobacteriota. They were more specialized in DOM utilization and facilitated community-wide carbon cycling. This study highlights the different roles of microbes in DOM transformation and provides a fundamental for developing optimal DOM control strategies.

Comparative analysis between full-scale A/A/O and A/O processes reveals the microbial roles in the transformation of dissolved organic matter

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.