不同预处理方法对剩余污泥厌氧发酵产氢的影响

Effect of different pretreatment on anaerobic fermentative hydrogen production from excess sludge

为了寻求适宜的预处理方法,提高剩余污泥发酵产氢率,通过间歇式试验考察了热、酸、碱和高温好氧4种预处理方法对剩余污泥发酵产氢的影响。结果表明,4种预处理方法均能有效抑制耗氢菌活性,同时促进污泥中微生物胞内物质的释放,使可溶性糖类物质和蛋白质质量浓度增加。其中高温好氧预处理的溶胞效果最好,可溶性糖类物质和可溶性蛋白物质质量浓度均最高,分别为878 mg/L和15606 mg/L,分别为原剩余污泥的10.58倍和58.45倍。4种方法预处理后的污泥发酵均获得了氢气,其中高温好氧预处理污泥产气率最高,为10.68 m L/g TS;其次是热预处理污泥,产气率为6.58 m L/g TS;碱预处理污泥产气率为3.63 m L/g TS;酸性预处理污泥产气率最低,仅为1.41 m L/g TS。

The excess sludge is one kind of biomass which contains many organics,mainly proteins and carbohydrates. In pursuit of suitable pretreatment,four pretreatments（ heat pretreatment,acid pretreatment,alkaline pretreatment and aerobic thermophilic digestion pretreatment） were used to enhance hydrogen production from excess sludge in batch tests. The experimental results showed that the four pretreatments could all increase soluble proteins and soluble carbohydrates because pretreatments could disrupt the floc structure and even the microbial cells of excess sludge. The concentration of soluble carbohydrates（ 878 mg / L） in the aerobic thermophilic digestion pretreated sludge was10. 58 times as in raw excess sludge and the concentration of soluble proteins（ 15 606 mg / L） was 58. 45 times higher. The results of batch anaerobic fermentation tests demonstrated that all of the four pretreatments could inhibit hydrogen consuming anaerobes and enhance the hydrogen production. The hydrogen yield of the aerobic thermophilic digestion pretreated sludge was the maximal（ 10. 68 mL /g TS） and that of the heat pretreated sludge was the next（ 6. 58 mL / g TS）. The hydrogen yield of the acid pretreated sludge was minimal（ 1. 41 mL / g TS）. It was concluded that the hydrogen yield of pretreated sludge was correlative with its soluble carbohydrates and soluble proteins. No methane could be detected in the anaerobic fermentation of all the four pretreated sludge,which suggesting that these pretreatments could totally inhibit the activity of methanogens. The volatile fatty acids were produced in anaerobic fermentation of pretreated sludge,mainly acetic acid,propionic acid and butyric acid. The maximal acetic acid（ 4668. 18 mg / L）,propionic acid（ 3 360. 63 mg / L） and butyric acid（ 4 706. 35 mg / L） were achieved in anaerobic fermentation of aerobic thermophilic digestion pretreated sludge. The pH values were between 4. 7 and 5. 5 at the end of fermentation.