温度降低对UMSR处理高氨氮低碳氮比养猪废水效能的影响

针对干清粪养猪废水高氨氮低碳氮比的特点，前期研发了升流式微氧活性污泥反应器（UMSR），在23℃条件下可实现碳氮的高效同步去除。为降低处理成本，在HRT 8 h和出水回流比45：1的条件下，对UMSR在20℃、17℃和15℃下的COD、NH₄⁺-N和TN去除效果进行了考察。结果表明，当温度阶段性地从20℃降低为15℃时，UMSR对养猪废水COD的去除率变化不大，均可保持在60%以上，但NH₄⁺-N和TN去除率分别从98.9%和79.8%左右大幅下降到了61.8%和39.7%左右。在17℃条件下，UMSR对COD、NH₄⁺-N和TN的去除率分别平均为62.4%、80.7%和71.2%，出水浓度分别为71、55.5和80.7 mg·L^-1左右，完全满足《畜禽养殖业污染物排放标准》（GB 18596-2001）的要求。在15～20℃范围内，温度的降低并没有显著改变UMSR系统的脱氮机制，仍然保持着以anammox为主要脱氮途径的特征。

Effect of lower temperature on performance of upflow microaerobic sludge reactor treating manure-free piggery wastewater with high NH4+-N and low COD/TN ratio

An upflow microaerobic sludge reactor (UMSR) has previously been constructed to treat manure-free piggery wastewater with high NH₄⁺-N and low COD/TN ratio, and illustrated a well synchronous removal of COD, NH₄⁺-N and TN at 23℃ with a hydraulic retention time (HRT) 8.0 h and an effluent reflux ratio 45:1. To decrease the cost of wastewater treatment, effect of lower temperature on the performance of the UMSR was investigated in the present study. With the same HRT and effluent reflux ratio, the temperature in the UMSR was decreased from 20℃ to 17℃ and then to 15℃ stage by stage. The results showed that the drop of temperature had no observable effect on COD removal in the UMSR, which remained above 60% throughout the operation. However, the lower temperature showed a remarkable effect on nitrogen removal. When the USBR got steady in performance at 20℃, the NH₄⁺-N and TN removal reached 98.9% and 79.8%, respectively. Since the temperature dropped to 15℃, NH₄⁺-N and TN removal in the USBR was decreased to 61.8% and 39.7%, respectively. At 17℃, the COD, NH₄⁺-N and TN removal averaged 62.4%, 80.7% and 71.2%. The effluent COD, NH₄⁺-N and TN of 71, 55.5 and 80.7 mg·L^-1, respectively, well met the Discharge Standard of Pollutants for Livestock and Poultry Breeding (GB 18596—2001). It was found that complete nitrification-denitrification, shortcut nitrification-denitrification and anaerobic ammonium oxidation (ANAMMOX) coexisted in the UMSR. Among the denitrification processes, ANAMMOX was the most important approach for NH₄⁺-N and TN removal, and had not been changed by the dropped temperature.