AnMBR对高浓度餐厨废水的处理效能

餐厨废水是一类高油、高盐、高氮等较为复杂的废水，在传统厌氧处理中面临污泥漂浮流失、有机负荷低及COD去除效果差等问题。通过构建中试规模厌氧膜生物反应器(anaerobic membrane reactor, AnMBR)处理餐厨废水，考察了3个运行阶段(污泥驯化阶段、容积负荷(volume loading rate, VLR)提升阶段和污泥停留时间(sludge retention time, SRT)缩短阶段)的厌氧消化性能、稳定性能、污泥性质和膜性能变化。结果表明，在污泥驯化阶段，低负荷(1.5 kg·(m³·d)⁻¹)污泥驯化方式能够实现AnMBR的快速启动，甲烷产率由227 mL·g⁻¹ (以COD计)迅速提升至267 mL·g⁻¹，COD去除率达到99%。在VLR提升阶段，当负荷由3.0 kg·(m³·d)⁻¹逐渐增加至12.0 kg·(m³·d)⁻¹时，甲烷产率由283 mL·g⁻¹升高并稳定至335 mL·g⁻¹左右，COD去除率达到98.5%。然而此阶段污泥浓度由13.39 g·L⁻¹迅速升高至45.59 g·L⁻¹，从而导致膜污染加剧，平均膜通量下降速率由0.53 L·(m²·h·d)⁻¹增至0.78 L·(m²·h·d)⁻¹。在SRT缩短阶段(由100 d缩短至40 d)，尽管排泥量由0.4 L·d⁻¹增加至1 L·d⁻¹，甲烷产率并没有受到明显影响，仍稳定在335 mL·g⁻¹左右，COD去除率达到98.9%。此外，缩短SRT增大了排泥量，反应器内污泥浓度由45.59 g·L⁻¹逐渐降低至45.27 g·L⁻¹，缓解了膜污染，膜通量下降速率减缓到0.42 L·(m²·h·d)⁻¹。在整个运行阶段，AnMBR对毒性物质氨氮具有良好的耐受能力，尽管体系内氨氮质量浓度高达2 600 mg·L⁻¹，VFA/ALK始终低于0.04，表明AnMBR不仅对外界环境变化有着较好的缓冲能力，而且对消化体系的内源性抑制因素也有着良好的耐受能力。综上，AnMBR在处理餐厨废水时表现了良好的处理性能和稳定性能。

Performance of an anaerobic membrane bioreactor treating high concentration kitchen wastewater

Kitchen wastewater is a kind of complex wastewater with high oil, high salt and high nitrogen. The traditional anaerobic reactors have been confronted with many problems such as sludge floating and loss, low organic load and poor COD removal efficiency during the process of treating kitchen wastewater. In this study, a pilot-scale anaerobic membrane reactor (AnMBR) was constructed to treat the kitchen wastewater, and its performance, stability, sludge properties and membrane flux were investigated at three stages: sludge cultivation, volume loading rate (VLR) increase and sludge retention time (SRT) decrease. The results showed that the domestication method of low VLR (1.5 kg·(m3·d)−1) could realize the rapid start-up of AnMBR, and the methane yield increased rapidly from 227mL·g−1(calculated by COD) to 267 mL·g−1 and the COD removal efficiency reached 99%. At the stage of VLR increasing from 3.0 kg·(m3·d)−1 to 12.0 kg·(m3·d)−1, the methane yield raised from 283 mL·g−1 to about 335 mL·g−1 and stabilize at it, the COD removal efficiency reached 98.5%. However, at this stage, the mixed liquor suspended solids (MLSS) increased rapidly from 13.39 g·L−1 to 45.59 g·L−1, which resulted in a membrane fouling aggravation with the average flux decline rate increasing from 0.53 L·(m2·h·d)−1 to 0.78 L·(m2·h·d)−1. At the stage of SRT decrease (from 100 days to 40 days), although the sludge discharge rate increased from 0.4 L·d−1 to 1 L·d−1, the methane yield was not significantly affected and still stabilized at about 335 mL·g−1, and the COD removal efficiency reached 98.9%. Furthermore, SRT decrease led to a gradual MLSS decrease in the reactor from 45.59 g·L−1 to 45.27 g·L−1, which alleviated the membrane fouling and led to the reduction of the average membrane flux decline rate to 0.42 L·(m2·h·d)−1. Besides, during the whole operation stage, AnMBR had a good tolerance to ammonia nitrogen, although the ammonia nitrogen mass concentration in the system was as high as 2 600 mg·L−1, VFA/ALK was always lower than 0.04. This indicated that AnMBR not only exhibited a good buffer ability to the changes of external environment, but also showed a good tolerance to the endogenous inhibitory factors of digestive system. In conclusion, AnMBR presented a good COD removal efficiency and digestion stability for treating kitchen wastewater.