外加铁对城市污泥厌氧消化产甲烷的作用

EFFECT OF ADDED IRON ON ANAEROBIC DIGESTION PROCESS OF MUNICIPAL SLUDGE IN METHANE PRODUCTION

为提高城市污泥厌氧消化产甲烷效率,除适量添加餐厨垃圾以提高有机质外,还在污泥中加入了机械加工企业产生的废铁屑,中温(39±1)℃下厌氧消化30 d,同时与加入等量纯铁粉对比,考察废铁屑和纯铁粉的产甲烷效率。结果表明:废铁屑组和纯铁粉组的累积产甲烷量分别达到340.33,336.52 m L/g,分别比不外加任何铁元素的空白组提高了54%、52%;上述两组在厌氧消化第10天产生的挥发性有机酸达到最大,分别为11051,10800 mg/L,比空白组高出16%、12%。消化第1天,废铁屑组和纯铁粉组的H_(2)组分比空白组提高了24%、12%;到第25天时,两组的CH_(4)组分分别比空白组提高了35%、30%。表明废铁屑中多孔的Fe OOH导致微生物絮体松散,使得废铁屑厌氧消化的产甲烷效果优于铁粉。

To improve the efficiency of methane production by anaerobic digestion process of municipal sludge,rusted scrap iron produced by mechanical processing plant was added to the sludge mixing with some kitchen waste to increase organic matters composition,and same amount of pure iron powder was added as the control group.The methane production effect of rusted scrap iron and pure iron powder was compared,after anaerobic digestion at medium temperature(39±1)℃for 30 days.The results showed that the cumulative methane production in the rusted scrap iron group and the iron powder group reached 340.33 m L/g and 336.52 m L/g,respectively,which increased by 54% and 52% compared with the blank group;the volatile organic acids produced by the above two groups on the tenth day of anaerobic digestion were 11051 mg/L and10800 mg/L,respectively,which were 16% and 12% higher than that of the blank group;as to the proportion of daily gas production components,on the first day,the proportion of H_(2) for rusted scrap iron group and pure iron powder group were increased by 24% and 12%,compared with that of the blank group;on the 25 th day,the proportion of CH_(4) for rusted scrap iron group and pure iron powder group were 35% and 30% higher than that of blank group.The porous Fe OOH in the rusted scrap iron led to a loose structure for microbial flocs,which resulted in a significant methanogenic effect of anaerobic digestion process than that of pure iron powder.