微波-Fe(Ⅱ)/S_(2)O_(8)^(2-)耦合强化污泥溶胞与定向甲烷转化

Enhancement for the rupture of waste activated sludge cells and directional methane conversion based on microwave-Fe(Ⅱ)/S_(2)O_(8)^(2-)combined pretreatment

本研究探讨了微波-Fe(Ⅱ)/S_(2)O_(8)^(2-)耦合预处理对污泥溶裂、甲烷转化以及有机物降解的影响,结果表明,单一微波预处理可促进污泥厌氧消化,而微波-Fe(Ⅱ)/S_(2)O_(8)^(2-)耦合预处理则有利于强化污泥细胞溶裂,缩短厌氧停留时间,提高有机质去除率,处理效果与微波瓦数和氧化剂投加量成正比.其中,微波辐射640 W,Fe(Ⅱ)/S_(2)O_(8)^(2-)=0.8/1.0 mmol·g^(-1)-TS为最佳预处理条件,此时污泥溶解性多糖(soluble polysaccharides,SPS)增溶量较对照组高7.5倍,厌氧产气率仅在4 d即可达到峰值,厌氧停留时间较其他预处理污泥缩短约75.7%,且SPS去除率达到98.6%.一级动力学模型模拟揭示,污泥水解速率与产甲烷性能无必然联系,基质本身的产甲烷潜力则是影响和决定其最终甲烷产量的关键制约因子.能量评估结果进一步表明,尽管耦合预处理未能获得明显的能量输出,但单位干基污泥的处理能耗节约20.1 kWh·kg^(-1),仅为原来的45%—60%.

In this study,the effect of microwave(MW)-Fe(Ⅱ)/S_(2)O_(8)^(2-)combined pretreatment on sludge cells rupture,biodegradability and subsequent methane producing potential were investigated.The results demonstrated that single microwave pretreatment could promote the anaerobic digestion of sludge,while the combined process could greatly promote the lysis of sludge cells,shorten the hydraulic retention time,and improve the removal rate of organics.The enhancement effect showed a close correlation with the applied MW power and oxidant dosage.The optimal condition was observed to be MW 640 W and Fe(Ⅱ)/S_(2)O_(8)^(2-)0.8/1.0 mmol·g^(-1)-TS.Under this condition,the solubilization degree of the sludge was 7.5-time higher than the control and the peak of methane production in subsequent anaerobic digestion was obtained after only 4 days,with 75.7%shorter start-up time than other samples.Also,the biodegradation of organic matter,especially soluble polysaccharides,reached the highest of up to 98.6%.The further analysis by fitting with the firstorder dynamic model demonstrated that the potential of methane production rather than the hydrolysis rate was necessarily related to methane production.Although a net energy output was not realized even under the optimal pretreatment conditions,the current result can save at least 20.1 kWh of specific energy consumption per kilogram dry sludge,which was only 45%-60%of traditional energy consumption.