剩余污泥含水率对中温固态厌氧消化的影响

Effect of Moisture Content on Mesophilic Solid-state Anaerobic Digestion of Excess Sludge

污泥厌氧消化是污泥资源化利用的重要途径，但传统的液态厌氧消化会产生大量处理成本较高的沼液，固态厌氧消化则能克服这个缺点。以脱水后的剩余污泥为原料，并用秸秆调节碳氮比，研究了中温（35℃）条件下含水率（65％～85％）对固态厌氧消化的影响。结果表明，消化初期产生高浓度的挥发性脂肪酸（VFA），并导致初期pH值迅速下降至5．5～6．2，VFA浓度和含水率呈正相关。含水率越高，反应启动越快，反应周期越短。当含水率为70％～80％时，VS的降解率达到56．0％-58．3％，甲烷产率为452．9～459．5mL／g。因此，对于污泥的中温固态厌氧消化，适宜的含水率为70％～80％。

Anaerobic digestion is an important way for the reutilization of excess sludge, but the treatment cost of the effluent from traditional liquid-state anaerobic digestion is very high. Solid-state anaerobic digestion can overcome the disadvantage. The effect of moisture content of 65 % to 85 % on mesophilie solid-state anaerobic digestion （35℃ ） of excess sludge was investigated by using rice straw to adjust the C/N ratio of the substrate. The results showed that high concentration of volatile fatty acids （VFA） was produced at the early stage of anaerobic digestion, which resulted in rapid decline of pH to 5.5 - 6.2. The concentration of VFA and moisture content were positively correlated. The higher the moisture content was, the faster the startup of the reactor was, and the shorter the reaction time was. When the moisture content was between 70% and 80% , the degradation rate of VS reached 56.0% to 58.3% and the methane yield was about 452.9 to 459.5 mL/g. Therefore, the optimum moisture content for the mesophilic solid-state anaerobic digestion of excess sludge was between 70% and 80%.