摘要
为明确底物成分对厌氧消化系统胞外聚合物(EPS)生成及起泡性能的影响,在批次实验中引入高碳水、高蛋白和高油脂3种厨余垃圾,检测了不同试验组EPS的产生特性(浓度、组成、结构、官能团等),及各类EPS和污泥的起泡特性参数(粘度、表面张力和相对疏水性)和起泡潜能参数(起泡趋势、泡沫稳定性、泡沫直径和液膜厚度),并分析了EPS特性与污泥特性的相关性.结果表明,底物不同的试验组产生了性质各异的EPS.底物组分越均衡越倾向于产气利用,而高碳水及对照组因碳水化合物含量过多,EPS总浓度显著高于其余实验组.碳水化合物、蛋白质和油脂分别会通过改变中间代谢产物、影响微生物产酶情况和增殖情况而改变EPS形态及组分.EPS结构方面,碳水组和对照组在高碳水化合物条件下,产生的EPS类腐殖质更多.官能团方面,高碳水底物下烷基含量减少,高蛋白底物下会产生更多亲水性含氮官能团,高油脂下羧酸含量增加,且3个试验组的EPS相对疏水性较对照组均有不同程度降低.相关性分析发现,污泥起泡能力与EPS类指标的相关性明显强于底物类别.污泥起泡趋势(FP)与松散结合型EPS(P<0.01,r=0.979)和溶解型EPS(P<0.05,r=0.678)相关性最强;EPS粘度对FP与泡沫稳定性(FS)也均具有积极作用(P<0.05),EPS表面张力增加有利于FS(P<0.05).底物对起泡的作用方面,碳水化合物可能是通过提高EPS粘度和亲水性,使污泥产生直径更大、稳定性更强的泡沫.蛋白质利用酶作用EPS表面张力下降,由此产生直径更小稳定性更差的泡沫,起泡现象得以缓解.油脂使松散结合型EPS减少(P<0.05,r=-0.649),同时分解产生的LCFA改变了紧密结合型EPS粘度(P<0.01,r=0.788)共同提高了FP.
To clarify the influence of substrates composition on the production characteristics and foaming performance of extracellular polymer(EPS)in anaerobic digestion system,three types of food waste,namely high-carbohydrate,high-protein and high-fat,were tested in batch experiments.The EPS production characteristics(concentration,composition,structure,functional groups,etc.),and parameters characterizing the foaming properties(viscosity,surface tension and relative hydrophobicity)and potential(foaming tendency,foam stability,foam diameter and liquid film thickness)of various types of EPS and sludge,were examined in different test groups.The correlation between EPS characteristics and sludge characteristics was also analyzed.The test groups with different substrates produced EPS with different properties.Specifically,the more balanced the substrate composition,the more it tended to be used for gas production,while the high carbohydrate and control groups had significantly higher total EPS concentrations than the rest experimental groups due to the excess carbohydrate content.Carbohydrates,proteins and oils influenced EPS morphology and composition by altering intermediate metabolites,affecting enzyme production and proliferation of microorganisms,respectively.In terms of EPS structure,more humic-like substances were produced under high carbohydrate conditions in the high-carbohydrate and control groups.In terms of functional groups,the alkyl group was reduced in the high-carbohydrate group,the high-protein group produced more hydrophilic nitrogenous functional groups,and the carboxylic acid content increased in the high-fat group.In addition,the relative hydrophobicity of EPS was reduced to varying degrees in all three experimental groups compared to the control group.The correlation analysis revealed that the sludge foaming capacity was significantly more correlated with EPS-related parameters than with substrate categories.Sludge foaming tendency(FP)was strongly correlated with loosely bound EPS(P<0.01,r=0.979)and so
作者
周滢月
张智
李蕾
杨屏锦
王小铭
彭绪亚
ZHOU Ying-yue;ZHANG Zhi;LI Lei;YANG Ping-jin;WANG Xiao-ming;PENG Xu-ya(Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment,Ministry of Education,Chongqing University,Chongqing 400045,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2023年第8期4046-4056,共11页
China Environmental Science
基金
国家自然科学基金资助项目(52170124)。
