In response to the intermittent discharge and frequent flow interruptions characteristic of rural domestic wastewater, this study evaluated the treatment performance and microbial mechanisms of basalt fiber (BF) felt as a novel biofilm carrier, with comparative analyses against traditional polyurethane (PU) carrier. Under continuous-flow conditions, both carriers showed no significant difference in the removal efficiencies of COD and NH4+-N. However, when switching to intermittent feeding mode with flow interruption, the BF reactor maintained high removal efficiencies for pollutants (COD, NH4+-N and TN removals averaged 90.5%, 89.4% and 64.5%, respectively), significantly outperforming the PU reactor (COD, NH4+-N and TN removals averaged 82.3%, 32.7% and 20.7%, respectively). High-throughput sequencing results revealed that the BF carrier significantly enriched nitrifiers (e.g., Nitrospira) and aerobic denitrifiers (e.g., Terrimonas and Bacillus) during the intermittent operation phase. Functional prediction further indicated increased abundances of functional genes associated with nitrification (amoA, hao), complete denitrification (narG, nosZ), as well as glycolysis (GAPDH) and the TCA cycle (IDH1, korA) related to NADH generation, suggesting an enhanced coupling mechanism of carbon and nitrogen metabolism in the BF system. Conversely, a significant reduction in microbial diversity and the abundance of relevant functional genes was observed on the traditional carriers. This study confirms that BF felt, serving as a biocarrier for rural domestic wastewater treatment, exhibits superior shock load resistance and nitrogen removal performance, which provides an efficient and reliable carrier option for decentralized wastewater treatment in rural areas.
Xu et al. (Mon,) studied this question.