Chemical and Biochemical Engineering, University of Western Ontario, Canada; Water Pollution Research Department, National Research Center, 33 El Bohoth St., P.O.12622, Dokki, Giza, Egypt.
Chemical and Biochemical Engineering, University of Western Ontario, Canada.
Water Res. 2022 Jul 15;220:118719. doi: 10.1016/j.watres.2022.118719. Epub 2022 Jun 7.
This study assessed the feasibility of a novel vacuum-enhanced anaerobic digestion technology, referred to as IntensiCarb (IC), under mild vacuum pressure (110 mbar), compared to a control (conventional fermenter), and evaluated the impact of the vacuum on the activities of various microbial groups. Both fermenters (test and control) were operated with mixed (50% v/v) municipal sludge at solids concentrations of 2-2.5%, pH of 7.8-8.1, 40-45 °C, a theoretical solids retention time (SRT) of 3 days with different hydraulic retention times (HRT). The intensification factor (IF) of the IC, defined as SRT/HRT, was controlled at 1.3 and 2.0. Simultaneous thickening and fermentation intensification were achieved. Compared with the control, the IC, despite the shorter HRTs, achieved 29.5 to 90.2% increase in the VFA yield (79 to 116 mg ΔVFA/ g VSS vs 61 mg ΔVFA/ g VSS), and 16.2% to 56.4% increase (280 to 377 mg ΔsCOD/ g VSS vs 241 mg ΔsCOD/ g VSS), in the hydrolysis yield. Fermentate from the IC exhibited comparable specific denitrification rates to acetate. Further, the solids-free condensate contained low nutrient concentrations, and thus was far superior to a typical centrates from dewatering as a carbon source. No adverse effects of vacuum on the activity of fermentative bacteria and methanogens were observed. This study demonstrated that the IC can be deployed as an intensification technology for both fermentation and anaerobic digestion of biosolids with the additional significant advantage, i.e. elimination of sidestream ammonia treatment requirements.
本研究评估了一种新型的真空增强厌氧消化技术（称为 IntensiCarb，简称 IC）在轻度真空压力（110 毫巴）下的可行性，与对照（传统发酵罐）相比，并评估了真空对各种微生物群活性的影响。两个发酵罐（测试和对照）都以混合（50% v/v）城市污泥为原料，固体浓度为 2-2.5%，pH 值为 7.8-8.1，40-45°C，理论固体停留时间（SRT）为 3 天，水力停留时间（HRT）不同。IC 的强化因子（IF）定义为 SRT/HRT，控制在 1.3 和 2.0。实现了同时浓缩和发酵强化。与对照相比，尽管 IC 的 HRT 较短，但 VFA 产率提高了 29.5%至 90.2%（79 至 116 mg ΔVFA/g VSS 比 61 mg ΔVFA/g VSS），水解产率提高了 16.2%至 56.4%（280 至 377 mg ΔsCOD/g VSS 比 241 mg ΔsCOD/g VSS）。IC 发酵液的比特异反硝化速率与乙酸相当。此外，无固形物的冷凝物含有较低的营养浓度，因此远优于典型的脱水浓缩物作为碳源。真空对发酵细菌和产甲烷菌活性没有不利影响。本研究表明，IC 可作为生物固体发酵和厌氧消化的强化技术，具有额外的显著优势，即消除了侧流氨处理的要求。
