Democritus University of Thrace, Dept. of Environmental Engineering, Xanthi, Greece.
Water Sci Technol. 2012;65(12):2251-7. doi: 10.2166/wst.2012.139.
Co-digestion of waste activated sludge (WAS) with agro-industrial organic wastewaters is a technology that is increasingly being applied in order to produce increased gas yield from the biomass. In this study, the effect of olive mill wastewater (OMW) on the performance of a cascade of two anaerobic continuous stirred tank (CSTR) reactors treating thickened WAS at mesophilic conditions was investigated. The objectives of this work were (a) to evaluate the use of OMW as a co-substrate to improve biogas production, (b) to determine the optimum hydraulic retention time that provides an optimised biodegradation rate or methane production, and (c) to study the system stability after OMW addition in sewage sludge. The biogas production rate at steady state conditions reached 0.73, 0.63, 0.56 and 0.46 l(biogas)/l(reactor)/d for hydraulic retention times (HRTs) of 12.3, 14, 16.4 and 19.7 d. The average removal of soluble chemical oxygen demand (sCOD) ranged between 64 and 72% for organic loading rates between 0.49 and 0.75 g sCOD/l/d. Reduction in the volatile suspended solids ranged between 27 and 30%. In terms of biogas selectivity, values of 0.6 l(biogas)/g tCOD removed and 1.1 l(biogas)/g TVS removed were measured.
共消化废活性污泥 (WAS) 和农业工业有机废水是一种越来越多地应用于从生物质中产生更高产气量的技术。在这项研究中，研究了橄榄油厂废水 (OMW) 对在中温条件下处理浓缩 WAS 的两个厌氧连续搅拌罐 (CSTR) 级联的性能的影响。这项工作的目的是 (a) 评估 OMW 作为共底物的使用以提高沼气产量，(b) 确定提供最佳生物降解率或甲烷产量的最佳水力停留时间，以及 (c) 研究在添加 OMW 后在污水污泥中的系统稳定性。在稳态条件下，水力停留时间为 12.3、14、16.4 和 19.7 d 时，沼气产率分别达到 0.73、0.63、0.56 和 0.46 l(沼气)/l(反应器)/d。在有机负荷率为 0.49 至 0.75 g sCOD/l/d 之间，可溶性化学需氧量 (sCOD) 的平均去除率在 64%至 72%之间。挥发性悬浮固体的减少量在 27%至 30%之间。就沼气选择性而言，测量到的沼气产率为 0.6 l(沼气)/g tCOD 去除和 1.1 l(沼气)/g TVS 去除。
