加挂填料种植狐尾藻提升A/O工艺处理猪场沼液的效果

为提升A/O工艺对猪场沼液中污染物的去除效果，实现高效率且低成本的运行模式，通过对A/O工艺加挂弹性填料种植狐尾藻来优化工艺。结果表明：当进水COD、TN和${{rm{NH}}_{rm{4}}^{rm{ + }}}$-N分别为441~948、401~1 579和369~1 594 mg·L−1时，改良A/O工艺系统出水COD、TN和${{rm{NH}}_{rm{4}}^{rm{ + }}}$-N去除率分别为42.5%~97.4%、36.9%~88.3%和94.2%~99.4%，均优于A/O工艺的去除效果且具有显著提升。综合考虑对污染物的去除效果以及企业运行成本，在水力停留时间为10 d时，改良A/O工艺出水水质达到最优，出水COD平均去除率可达75.3%，对${{rm{NH}}_{rm{4}}^{rm{ + }}}$-N平均去除率为96.2%~99.5%，TN的出水质量浓度为70~296 mg·L−1。此外，可结合多级改良A/O工艺和组合工艺进一步优化出水水质。除微生物同化作用以及硝化反硝化途径外，系统中含氮类物质还可通过狐尾藻植物去除。改良A/O工艺中狐尾藻植物能够大量生长，含水量为88.8%~89.0%，TP和TN质量分数分别为3.4~5.2 g·kg−1和51.4~53.8 g·kg−1，TN质量分数要远高于普通富营养化水体栽培的狐尾藻，这说明狐尾藻在改良A/O工艺中能够更好的吸收污染水体中的含氮物质。以上结果可为改良A/O工艺对猪场沼液的优化处理提供参考。

Treatment effect of piggery biogas slurry by improved A/O process with adding packing and planting myriophylla

In order to improve the removal efficiency of pollutants from piggery biogas slurry by traditional A/O system and realize the operation mode of high efficiency and low cost, the process was optimized by adding elastic packing to A/O system and planting myriophylla. The results showed that when the influent COD, TN and ${rm{NH}}_{rm{4}}^{rm{ + }}$-N were 441~948, 401~1 597 and 369~1 594 mg·L−1, the removal rates of COD, TN and ${rm{NH}}_{rm{4}}^{rm{ + }}$-N were 42.5%~97.4%, 36.9%~88.3% and 94.2%~99.4% respectively, which were better than those of A/O system and had a significant improvement. In addition, the effluent quality can be further optimized by combining multi-stage improved A/O system and combined system. Considering the removal efficiency of pollutants and the operation cost of the enterprise, the HRT of 10 d was most suitable for the actual operation of the improved A/O system, the average removal rate of COD in the effluent was 75.3%, the average removal rate of ${rm{NH}}_{rm{4}}^{rm{ + }}$-N was 96.2%~99.5%, and the effluent concentration of TN was 70~296 mg·L−1. In addition to microbial assimilation and nitrification and denitrification, nitrogen-containing substances in the system could also be removed by myriophylla. In the improved A/O system, myriophylla could grow in large quantities with water content of 88.8%~89.0%, TP and TN contents of 3.4~5.2 g·kg−1 and 51.4~53.8 g·kg−1, respectively, and the concentration of TN was much higher than that of myriophylla in eutrophic water, which showed that myriophylla in the improved A/O system had better absorption performance toward nitrogen in the polluted water. The above results provide a reference for the optimization of piggery biogas slurry treatment by improved A/O system.