中试厌氧膜生物反应器处理养猪废水

猪场养殖废水是一类有机污染物浓度高、悬浮物多、性质复杂的废水，在传统厌氧处理中存在消化污泥流失及处理效率低等问题。本研究采用中试规模外部浸没式厌氧膜生物反应器处理猪场实际废水，设计处理水量为1 m³·d⁻¹，在HRT分别为8、5、3 d的3个阶段连续运行4个多月，考察了厌氧膜生物反应器的沼气产量、运行稳定性、污染物去除效果及膜组件运行性能和清洗效果。结果表明，系统运行期间ORP在−486~−545 mV；随着HRT缩短，有机负荷由0.5~1.88 kg·(m³·d)⁻¹升高到5 kg·(m³·d)⁻¹，沼气产量逐渐增大，产率为0.38~0.45 m³·kg⁻¹。在整个运行过程中，VFA/ALK始终小于0.1，系统运行稳定。对TCOD、溶解性COD、氨氮、TN、TP去除率分别达到74%~86%、48%~68%、7%~12.8%、4.6%~16.7%、5%，其中溶解性COD去除率占总COD去除率的55%左右。系统运行期间初始膜通量设定为5 L·(m²·h)⁻¹，在HRT=8 d时，清洗周期为20 d，随后不断缩短，当HRT为3 d时，清洗周期仅为10 d。通过水冲洗与化学清洗相结合的方式可有效缓解膜污染，进而恢复膜通量。以上研究结果可以为厌氧膜生物反应器处理猪场养殖废水工程应用提供参考。

Performance of a pilot anaerobic membrane bioreactor treating swine wastewater

Swine wastewater is a kind of wastewater with high concentration of organic pollutants, suspended solids and complex properties. Traditional anaerobic treatment has some problems such as loss of digested sludge, low efficiency and so on. In this study, a pilot-scale external submerged anaerobic membrane bioreactor was used to treat the actual wastewater from a pig farm. The designed water treatment capacity was 1 m3·d−1. In three stages of HRT=8 d, 5 d, and 3 d, the bioreactor was operated continuously for more than 4 months. The biogas production of anaerobic membrane bioreactor, operation stability, pollutant removal efficiency, as well as membrane module operation performance and cleaning efficiency were investigated. The results showed that the ORP was between −486 mV and −545 mV during the system operation. With the shortening of HRT, the organic load increased from 0.5~1.88 kg·(m3·d)−1 to 5 kg·(m3·d)−1, and the biogas production increased gradually, the yield was between 0.38 to 0.45 m3 kg−1. The VFA/ALK was always less than 0.1 during the whole process, the system maintained a stable running. The removal efficiencies of TCOD, SCOD, NH3-N, TN, and TP were 74%~86%, 48%~68%, 7%~12.8%, 4.6%~16.7%, and 5%, respectively. The removal efficiency of SCOD accounted for about 55% of TCOD. During the system operation, the initial membrane flux was set to 5L·(m2·h)−1. At HRT of 8 d, the cleaning period was 20 d, and then it was reduced continuously. At HRT of 3 d, the cleaning period was only 10 d. The combination of water washing and chemical cleaning could effectively alleviate membrane fouling and restore membrane flux. The above research results can provide a reference for the engineering application of anaerobic membrane bioreactor to treat swine wastewater.