城市污水处理厂剩余污泥厌氧消化试验研究

Study on Anaerobic Digestion of Excess Activated Sludge from Municipal Wastewater Treatment Plant

以北京市某污水处理厂的剩余污泥为研究对象,对该污泥的理论产气量进行了估算,考察了投加接种污泥和未投加接种污泥条件下污泥厌氧消化的产气情况,并分析了污泥消化前、后的泥质特点。结果表明:与未接种条件相比,污泥厌氧消化前采用投加接种污泥的方式可大大促进消化反应的进行,加快污泥的产气速率,使厌氧消化周期缩短近1/4,但对污泥的总产气量影响较小;在厌氧消化正常运行条件下,污泥产气量达到总产气量的90%时所需反应时间约为16d,可将其作为污泥厌氧消化工艺较为理想的消化周期;剩余污泥的消化性能差、产气率低、试验产气量占理论产气量的比例<50%,在工程上单独的剩余污泥不宜采用厌氧消化工艺处理。

The excess activated sludge from a municipal wastewater treatment plant in Beijing was selected as the study object. The theoretic biogas production was estimated, the sludge anaerobic digestion tests were undertaken with seeding sludge and without seeding sludge respectively, meanwhile, the main contents of sludge were analyzed before and after digestion. The results indicate that in comparison to without seeding condition, adding seeding sludge before anaerobic digestion can enhance the efficiency of anaerobic digestion, promote the velocity of biogas production, and cut down 1/4 of the whole digestion cycle, but the total biogas production is hardly affected. The time when the biogas production reaches 90% of total biogas production is about 16 d in the case of well-balanced digestion, and so, 16 d can be chosen as reasonable sludge anaerobic digestion time. In addition, the ratio of test biogas production to theoretic biogas production is less than 50%, and sole excess activated sludge is not suitable to be treated with anaerobic digestion technology in engineering because of poor digestibility and very low biogas production.