固定床厌氧反应器处理高浓度糖蜜废水

为开发高效处理高浓度有机废水的厌氧沼气发酵技术，以活性炭纤维作为生物膜载体，在实验室规模上对固定床厌氧反应器处理高浓度糖蜜废水的运行性能进行了研究。初始进水COD为5 000 mg/L，水力停留时间（HRT）保持在2 d左右。在进水COD为47 000 mg/L以内时，相应的有机容积负荷（OLR，COD含量）达到21.38 kg/(m3×d)，COD去除率保持在86%以上，沼气容积产气率为9.51 L /(L×d)，甲烷容积产气率为6.46 L /(L×d)；当OLR进一步从21.38 kg/(m3×d) 逐步升高到35.13、39.06、44.88 kg/(m3×d) 时，COD去除率从86.48%分别降低到74.40%，67.02% 和63.50%，相应的沼气容积产气率为13.71，13.98和11.44 L/(L×d)，甲烷容积产气率为8.84，8.67和5.89 L/(L×d)。进水的pH值通常在3.5～5.6之间，OLR低于35.13 kg/(m3×d) 时，无需对pH值进行中和调节，出水的pH值自然维持在6.8～7.6的良好状态，超出此范围，则需加碱对进水的pH值作适当调节。最终进水COD高达78 600 mg/L，相应的OLR为44.88 kg/(m3×d)。在165 d的运行过程中污泥形成量小，没有发生堵塞现象，固定床厌氧反应器表现出高效的处理酸性高浓度有机废水和较强的抗负荷冲击的能力。

Treatment of high strength molasses wastewater with anaerobic fixed-bed reactor

To exploit an efficient technology to treat high strength wastewater by biogas fermentation, a laboratory-scale experiment were carried out to assess the performance of an anaerobic fixed-bed reactor (AFBR) packed with active carbon fibre as biofilm carrier for treating an acidic and high strength molasses wastewater. The continuous operation of the system was started using an initial chemical oxygen demand (COD) concentration of 5 000 mg/L at a hydraulic retention time (HRT) around two days. When the reactor was fed with COD under 47 000 mg/L, the relevant organic loading rate (OLR) was equivalent to 21.38 kg/(m3×d), the COD removal efficiency was above 86%, biogas and methane productivities of unit volume of 9.51 and 6.46 L/(L×d) were achieved respectively at that level. COD removal efficiency decreased respectively from 86.48% to 74.40%, 67.02% and 63.50% when OLR were increased from 21.38 to 35.13, 39.06 and 44.88 kg/(m3×d), and the relevant biogas productivities of unit volume were 13.71, 13.98 and 11.44 L/(L×d), and the methane productivities of unit volume were 8.84, 8.67 and 5.89 L/(L×d), respectively. Influent pH value of the AFBR was usually ranged between 3.5-5.6 without any pretreatment. Effluent pH value was ranged spontaneously on a feasible condition of 6.8-7.6 after methane fermentation. When the pH value was beyond the range of 6.8-7.6, the alkalinity was required to maintain the pH value at a suitable range. With the experiment progressing, a high strength influent COD of 78 600 mg/L was achieved, which was equivalent to an OLR of 44.88 kg/(m3×d). The anaerobic fixed-bed reactor presented an efficient treatment of acidic and high strength organic wastewater, and a strong anti-impact load capacity. The sludge production was so low that the reactor did not wall up in the process of 165-day operation. Therefore, it can save managing and economic cost.