Thermophilic High Speed Treatment of Wastewater by a Novel Anaerobic UASB Reactor

迄今为止，所有实际规模的UASB工艺都采用了中温或室温条件。目前，除了一个示范规模的工艺外，还没有运行中的嗜热UASB工艺。与中温工艺相比，高温UASB工艺的颗粒形成困难或不稳定是阻碍其推广应用的主要原因之一，为了考察新型高温UASB反应器的运行性能和滞留污泥的产甲烷活性，实验室规模的UASB反应器通过在嗜热条件（55 ℃）下进料醇类废弃物运行约2年。采用中温生长的颗粒污泥接种于UASB反应器，该反应器具有多级气固分离器，颗粒污泥的SVI低，稳定性好。由于建立了良好的沉降性，高活性的颗粒污泥，反应器最终允许100 kgCOD/m3/天的体积有机负荷，COD去除率约为85- 90%。剩余污泥的产甲烷活性分别为乙酸2.9gCOD/gVSS/d、丙酸0.69gCOD/gVSS/d和氢气16.2gCOD/gVSS/d。丙酸盐进料的产甲烷活性的低值相比，其他嗜热菌群，表明丙酸盐的分解主要是在嗜热甲烷发酵过程中的限速步骤。

All practical-scale UASB processes constructed so far have adopted either mesophilic or ambient temperature conditions. There is at present no thermophilic UASB process in operation, except one demonstration-scale process. One of the main causes hindering the dissemination of thermophilic UASB process may be the difficulty or less reliability of granule formation, compared with mesophilic processes.In order to investigate the performance of new developed thermophilic UASB reactor and the behavior of methanogenic activities of the retained sludge, the laboratory-scale UASB reactor was operated approximately 2 years by feeding with an alcohol distilllery wast under thermophilic conditions (55ﾟC). The reactor was inoculated with mesophilically-grows granulated sludge harvested from an UASB reactor receiving a carbohydrate (mainly juice) waste water.The novel thermophilic UASB reactor having a multistage of gas solid separator resulted in a low SVI and good stability of retained granulated sludge. As a result of establishment of well-settleable, high-activity granuled sludge, the reactor allowed ultimately a volumetric organic loading of 100kgCOD/m3/day, with a COD removal efficiency of around 85-90%. Methanogenic activities of the retained sludge reached finally up to 2.9g COD/g VSS/d for acetate, 0.69g COD/g VSS/d for propionate, and 16.2g COD/g VSS/d for hydrogen. Low values of the propionate-fed methanogenic activity compared to other thermotrophic groups, indicate that the propinate breakdown is mostly subject to be a rate-limiting step in thermophilic methane fermentation process.