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

到目前为止，所有实际规模的UASB工艺都采用了中温或常温条件。目前，除一个示范规模的工艺外，还没有运行中的高温UASB工艺。高温UASB工艺推广的主要原因之一可能是与中温工艺相比，颗粒形成困难或可靠性较差。为了考察新开发的高温UASB反应器的性能和剩余污泥的产甲烷活性，实验室规模的UASB反应器在高温条件下(55ﾟC)投加酒精废液运行约2年。接种中温生长颗粒污泥的UASB反应器接收碳水化合物(主要是果汁)废水。新型高温UASB反应器具有多级气固分离器，剩余颗粒污泥具有较低的SVI和良好的稳定性。由于建立了沉降良好、活性高的颗粒污泥，该反应器最终允许的体积有机负荷为100kgCOD/m~3/天，COD的去除效率约为85%-90%。剩余污泥的产甲烷活性最终达到乙酸盐2.9g COD/g VSS/d、丙酸盐0.69g COD/g VSS/d和氢气16.2g COD/g VSS/d。与其他热养组相比，丙酸补给的产甲烷活性较低，这表明丙酸酯的分解在嗜热甲烷发酵过程中主要是一个限速步骤。

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.