城市有机垃圾发酵工艺研究

THE STADIES ON THE FERMENTATION TECHNOLOGY OF THE MUNICIPAL ORGANIC REFUSE

用先好氧后厌氧发酵、两步发酵和高固体浓度发酵三种方法对城市有机垃圾厌氧产甲烷进行了研究。结果表明:前者具有启动快,产气量高,处理周期短等优点。而直接采用厌氧发酵,由于挥发酸大量积累,启动困难,产气量少。采用两步法发酵可显著提高挥发酸和甲烷产量,还能提高城市固体废物的生物降解率。Ts在20％～50％以下时高固体浓度发酵能正常产甲烷,最终pH和挥发酸均正常。在此范围内随着Ts的增大甲烷产量逐渐减少。Ts浓度在50％时产甲烷量大大下降。

Production of methane from the municipal organic refuse using aerobic-anaerobic fermentation, two-phase fermentation and high solid concentration fermentation is studied. The results atlained are as follows:The aerobic-anaerobic fermentation of municipal organic refuse can speed up the start process, shorten the cycle and raise the production rate of methane gas. Due to the au-amulation of volatile fatty acid (VFA) in the direct anaerobic fermentation, the start of the process is very difficult, and the production rate of methane gas is very low.The two-phase fermentation of municipal organic refuse increases VFA concentration, methane production, and municipal solid waste biological degradation obviouslly.(n the anaerobic fermentation of high concentration organic refuse, when the total solid (Ts) concentration is below 20-50%, the production of methane is normal, and the final pH and VFA are normal, too. The yield of the produced methane reduces gradually with the increase of Ts concentration but the yield of the produced methane reduces significantly, when the Ts concentration reaches 50%.