剩余污泥中温和高温厌氧水解酸化产VFAs性能研究

Study on VFAs production performance of anaerobic hydrolytic acidification of excess sludge at mesophilic and thermophilic condition

通过对比中温(35℃)和高温(50℃)厌氧产酸过程中挥发性有机酸(VFAs)含量与成分的变化,研究温度对剩余污泥的颗粒粒径、颗粒有机物降解情况、可溶性化学需氧量(SCOD)及挥发性有机酸(VFAs)的影响。结果表明,高温厌氧发酵可以显著促进污泥絮体解离,污泥分解率可达41.10%,微生物反应机率增加,反应效率提高。中温发酵和高温发酵过程中颗粒性有机物的水解过程均遵循一级反应动力学,且高温水解速率常数显著高于中温水解速率常数。中温水解液中未知溶解性有机物积累量高,转化慢,可能是中温发酵产酸效果低于高温条件的原因之一。高温发酵获得的VFAs约为中温VFAs产量的2倍,其中有机酸异戊酸和异丁酸的比例较高,二者约占VFAs的50%;中温发酵过程VFAs的组分单一,主要为乙酸。水解液中氨氮的增加量与颗粒型蛋白质的分解量存在强相关关系,高温发酵下的氨氮转化因子显著高于中温发酵的氨氮转化因子。

The effects of temperature on sludge particle size,degradation of organic matter,soluble chemical oxygen demand(SCOD)and volatile organic acids(VFAs)of excess sludge were investigated by comparing content and composition of VFAs during anaerobic acidification at mesophilic(35℃)and thermophilic(50℃).The results showed that thermophilic anaerobic acidification could significantly promote sludge particle dissociation.Sludge decomposition rate could reach 41.10%.Microbial reaction probability increased and reaction efficiency improved.The hydrolysis process of particulate organic matter in both mesophilic and thermophilic acidification followed first-order reaction kinetics,and the thermophilic hydrolysis rate constant was significantly higher than that of mesophilic hydrolysis.The high accumulation and slow conversion of unknown dissolved organic matter in mesophilic hydrolysate may be one of the reasons for the lower acidification effect of mesophilic fermentation.The VFAs obtained from thermophilic fermentation were about twice the yield of mesophilic fermentation,with a high proportion of isovaleric acids and isobutyric acid,both of which accounted for about 50%of the VFAs.The composition of VFAs during mesophilic fermentation was single,mainly acetic acid.The increase of ammonia nitrogen in the hydrolysate was strongly correlated with the decomposition amount of granular proteins.The ammonia nitrogen conversion factor under thermophilic fermentation was significantly higher than that of mesophilic fermentation.