大薸对规模化奶牛场污水的耐受性和净化效果

为考察大薸对高浓度畜禽污水净化的可行性，通过室内模拟大薸处理奶牛场污水试验，明确大薸在不同类型污水中的生长状况和生理响应，研究大薸对氮、磷和有机物等的净化效果，并通过高通量测序分析微生物群落变化，揭示微生物群落与常规污染物去除之间的关系。结果显示，大薸能够耐受的污水浓度以化学需氧量（COD_Cr）计]为0~2 000 mg·L^-1原水、0~750 mg·L^-1厌氧池和氧化塘污水。当大薸受到高浓度污水胁迫时，叶绿素含量明显减少，过氧化氢酶、过氧化物酶和超氧化物歧化酶活性明显升高。在耐受范围内，大薸对奶牛场3种污水具有良好的净化效果：0~10 d内对污染物去除较快，10~20 d内去除率上升缓慢；大薸对原水中总氮、氨氮、总磷和CODCr的去除率分别为84.7%~92.7%、90.6%~96.7%、30.0%~93.1%、67.3%~77.2%，而对厌氧池和氧化塘污水的净化效果略差。从微生物角度分析得出，奶牛场污水微生物以变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）和拟杆菌门（Bacteroidetes）为主，且大薸处理组内的微生物群落结构与无植物对照组明显不同，其中蓝藻菌门相对丰度差异最为明显。微生物群落与水体多项指标显著相关（P<0.05），说明微生物在污染物去除中起重要作用。本研究结果验证了大薸处理高浓度畜禽污水的可行性，为奶牛场污水处理提供了理论基础和技术支撑。

Tolerance and purification effects of Pistia stratiotes L. on dairy wastewater

To investigate the feasibility of livestock wastewater purification by the floating plant Pistia stratiotes L., an experimental study was conducted using P. stratiotes L. treatments of dairy wastewater to clarify the growth status and physiological responses of P. stratiotes L. in different types of wastewater and investigate the purifying effects on nitrogen, phosphorus, and organic matter. The changes in microbial communities were also analyzed using high-throughput sequencing to reveal the relationship between microbial communities and the removal of conventional pollutants. The results showed that the tolerance ranges were 0-2 000 mg·L^-1 and 0-750 mg·L^-1 for raw and anaerobic and oxidized pond wastewater, respectivelymeasured as chemical oxygen demand(COD_Cr)]. When P. stratiotes L. was subjected to high concentrations of wastewater, the chlorophyll content was markedly reduced, and the activities of three enzymes(catalase, peroxidase and superoxide dismutase) were significantly increased. Within the tolerance range, P. stratiotes L. showed good purification effects on the three wastewater types from dairy farms. Pistia stratiotes L. had a rapid purification speed in the first 10 days, which slowly inecreased within 10-20 days. After treatment with P. stratiotes L., the removal rates of total nitrogen, ammonia nitrogen, total phosphorus, and COD_Cr in raw wastewater were 84.7%-92.7%, 90.6%-96.7%, 30.0%-93.1%, and 67.3%-77.2%, respectively; however, the purification effect of P. stratiotes L. in anaerobic and oxidation ponds decreased slightly. Regarding the microbial communities, Proteobacteria, Firmicutes, and Bacteroidetes, were the main species in different dairy wastewaters. The microbial community structures in the P. stratiotes L. treatment group and non-plant control group were significantly different; in particular, the relative abundance of Cyanobacteria was distinct. The correlation between the microbial community and several indexes of wastewater was significant(P<0.05), indicating that microorganisms played an important role in the removal of pollutants. This study verified the feasibility of P. stratiotes L. in treating wastewater with high concentrations of pollutants and provides a theoretical basis and technical support for dairy farm wastewater treatment.