School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
School of Intelligent Manufacturing Technology, Nanyang Vocational College, Xixia 474550, China.
Sci Total Environ. 2024 Jul 10;933:173074. doi: 10.1016/j.scitotenv.2024.173074. Epub 2024 May 9.
Rural domestic poses a significant challenge to treatment technologies due to significant fluctuations in both water quality, particularly in terms of carbon concentration, and quantity. Conventional biological technology, such as anaerobic-anoxic-oxic (AO) systems, is inefficient. In this work, a continuous pilot-scale anoxic-anaerobic-anoxic-oxic (AO) reactor with a moving bed biofilm reactor (MBBR) system was constructed and optimized to improve the treatment efficiency of rural domestic wastewater. The sludge return ratio, volume ratio of the oxic-to-anoxic zone (Voxi/Vano), step-feeding and hydraulic retention time (HRT) at low temperature were considered the main parameters for optimization. Microbial analysis was performed on both the mixed liquor and carrier of the A3O-MBBR system under initial and post-optimized conditions. The results indicated that the AO-MBBR improved the treatment efficiency of rural domestic wastewater, especially for total phosphorus (TP), which increased by 20 % compared with that of the AO-MBR. In addition, the removal efficiencies of nitrogen and phosphorus were further optimized, and the average concentrations of total nitrogen (TN) and TP in the effluent reached 2.46 and 0.364 mg/L, respectively, at a sludge reflux ratio of 100 or 150 %, Voxi/Vano =200 %, step-feeding of 0.5Q/0.5Q (anaerobic/anoxic) and HRT of 15 h at low temperature in the AO-MBBR, which met standard A of GB18918-2002, China (TN < 15 mg/L, TP < 0.5 mg/L). The average rate of attaining the standard increased by 58.63 % (post optimization). The microbial analysis showed an increase in species diversity and richness after the parameters were optimized. Moreover, compared to the microbial community structure before optimization, the post-optimization exhibited a more stable microbial structure with a significant enrichment of functional bacteria. Defluviimonas, Novosphingobium and Bifidobacterium, considered as the dominant nitrification or denitrifying bacteria, were enriched in the suspended sludge of the MBBR reactor, which the relative abundance increased by 3.11 %, 3.84 %, and 3.24 %, respectively. Further analysis of the microbial community in the carrier revealed that the abundance of Nitrospira and the denitrifying bacteria carried by the carrier were much greater than those in the suspended sludge. Consequently, the microorganism cooperation between suspended sludge and biofilm might be responsible for the improved performance of the optimized AO-MBBR.
农村生活污水水质水量波动大，尤其是碳源浓度和水量变化大，给处理技术带来很大挑战。传统生物技术如厌氧-缺氧-好氧（AO）系统效率较低。本研究构建并优化了连续中试规模的缺氧-厌氧-缺氧-好氧（AO）移动床生物膜反应器（MBBR）系统，以提高农村生活污水的处理效率。污泥回流比、好氧区与缺氧区体积比（Voxi/Vano）、分步进水和低温下的水力停留时间（HRT）被视为优化的主要参数。在初始和优化后条件下，对 A3O-MBBR 系统的混合液和载体进行了微生物分析。结果表明，AO-MBBR 提高了农村生活污水的处理效率，特别是对总磷（TP）的去除率提高了 20%，优于 AO-MBR。此外，氮磷的去除效率进一步优化，在低温下，当污泥回流比为 100%或 150%、Voxi/Vano=200%、分步进水为 0.5Q/0.5Q（厌氧/缺氧）、HRT 为 15 h 时，AO-MBBR 对总氮（TN）和 TP 的平均去除率分别达到 2.46 和 0.364mg/L，达到中国《GB18918-2002》一级 A 标准（TN<15mg/L，TP<0.5mg/L）。优化后的达标率提高了 58.63%。微生物分析表明，参数优化后物种多样性和丰富度增加。与优化前的微生物群落结构相比，优化后的微生物结构更加稳定，功能细菌得到显著富集。脱氮硫杆菌、新鞘氨醇单胞菌和双歧杆菌被认为是硝化或反硝化的优势菌，在 MBBR 反应器的悬浮污泥中得到了富集，相对丰度分别增加了 3.11%、3.84%和 3.24%。对载体中微生物群落的进一步分析表明，载体中硝化菌和反硝化菌的丰度明显大于悬浮污泥。因此，悬浮污泥和生物膜之间的微生物协同作用可能是优化后的 AO-MBBR 性能提高的原因。
