热、热碱处理对污泥溶胞和溶解性有机物的影响

污泥有机物的水解是厌氧消化过程中的限速步骤,预处理可以有效地将污泥固体有机物转化为溶解态有机物,从而提高有机物降解速率和甲烷转化速率.本文研究了热、热碱处理(两种常用的预处理方法)对污泥溶胞释放溶解性有机物的组成、相对分子质量分布和结构的影响.结果表明,热、热碱处理均能大量释放溶解性有机物,相比对照组污泥,溶解性化学需氧量可分别增加21.9倍(热处理)和47.8倍(热碱处理).两种预处理会改变溶解性有机物相对分子质量分布,且含量最多的有机物相对分子质量减小.两种预处理均对污泥溶解性有机物中的主要组分(蛋白质)有水解作用,且热碱处理效果更显著.三维荧光光谱分析表明溶出的有机物中溶解性微生物副产物类物质和胡敏酸类物质难以被两种预处理进一步水解.另外,两种预处理不仅使污泥溶解性物质中出现新的有机结构,还会使原有的有机结构发生变化,甚至消失.

Effects of Heat and Heat-alkaline Treatments on Disintegration and Dissolved Organic Matter in Sludge

The hydrolysis of sludge organic matter is the rate-limiting step of anaerobic sludge digestion. Because pretreatments can effectively convert the solid organic matter into dissolved organic matter, it can improve the degradation rate and methane conversion rate of organic matter. In this study, the effects of heat and heat-alkaline treatments (two common pretreatments) on the composition, relative molecular weight distribution, and structure of dissolved organic matter in sludge were studied. The results showed that the heat and heat-alkaline treatments released a large amount of organic matter, which resulted in the SCOD increasing 21.9 times (heat treatment) and 47.8 times (heat-alkaline treatment). These pretreatments changed the molecular weight distribution of dissolved organic matter and decreased the molecular weight of the organic matter to the greatest degree. The results of three-dimensional fluorescence spectroscopy showed that both of the pretreatments can hydrolyze protein, the main component of sludge soluble organic matter, with the heat-alkaline treatment being more significant. In dissolved organic matter, the byproducts of the microorganisms and humic acids are not easily hydrolyzed further by the two pretreatments. In addition, the two pretreatments led to the appearance of new organic structures and the change and even disappearance of the original organic matter.