Purification effect and microbial community structure characteristics of modular constructed wetlands on rural domestic sewage

Abstract Modular artificial wetlands represent an effective engineering approach for purifying domestic sewage. This study investigates the purification efficiency of modular wetlands in treating rural domestic sewage by analyzing water quality indicators and microbial community structures under different inflow methods. The results reveal a subtle relationship between hydraulic retention time and the concentrations of various physicochemical indicators in the effluent, the latter demonstrating a trend of initial decrease followed by stabilization.The static series modular constructed wetlands exhibit removal rates of 86.21% for total phosphorus (TP), 88.68% for total nitrogen (TN), 88.70% for nitrate nitrogen (NO3−-N), 96.80% for ammonium nitrogen (NH4+-N), and 97.62% for chemical oxygen demand (COD). In comparison, the circular series modular artificial wetland achieves removal rates of 86.18%, 91.56%, 89.24%, 96.73%, and 97.39% for TP, TN, NO3−-N, NH4+-N, and COD in rural domestic sewage, respectively. Analysis of the microbial community structures in these modular wetlands demonstrates that the static series exhibits higher microorganism abundance, while the cyclic series shows greater species diversity.These findings emphasize the intricate interplay between microbial communities and the purification processes within modular wetlands.