摘要
基于2022年11座城镇中小规模污水厂全年数据,从污水处理全过程角度系统分析了 3种典型工艺(AAO、MSBR和氧化沟)的碳排放,并采用偏最小二乘法结构方程模型(PLS-SEM)研究了不同进水特征(TP、TN、BOD5、COD、进水量和碳氮比)对碳排放的影响作用.结果表明,间接碳排放占中小规模污水厂总碳排放的主导地位(69.5％),电耗碳排放是最大的来源(43.1％);MSBR工艺的评价碳排放强度[(0.363±0.007)kg·m-3]低于 AAO工艺[(0.439±0.099)kg·m-3]和氧化沟工艺[(0.396±0.025)kg·m-3],具有更优的低碳运行水平.中小规模污水厂各部分碳排放强度占比依次为:生物处理(58.7％)＞污泥脱水+除臭(17.9％)＞深度处理(17.3％)＞预处理(6.1％).其中生物处理部分分别占3种工艺的51.5％、53.9％和73.1％.另外,进水COD质量浓度和碳氮比分别对直接碳排放(N2O和CH4)有显著正向影响(路径系数为0.584和0.5)和显著负向影响(路径系数为-0.416);进水TN、BOD5和TP质量浓度分别对间接碳排放(电耗)和间接碳排放(物耗)有显著正向影响(路径系数分别为0.078、0.537和0.5).中小规模污水厂碳削减可从碳排放强度减量、低碳运行水平优化和政府调控加强管理这3个方面进行.
Abstract
The carbon emissions of three typical processes(AAO,MSBR,and oxidation ditch)were systematically analyzed from the perspective of the whole wastewater treatment process based on the annual data of eleven urban small and medium-scale WWTPs in the year 2022,and the effects of different influent characteristics(TP,TN,BOD5,COD,influent volume,and COD/TN)on the carbon emissions were studied by using the partial least squares structural equation modeling(PLS-SEM)method.The results showed that indirect carbon emissions dominated the total carbon emissions of small and medium-scale WWTPs(69.5％),and carbon emissions from electricity consumption were the largest source(43.1％);the evaluated carbon emission intensity of the MSBR process[(0.363±0.007)kg·m-3]was lower than that of the AAO process[(0.439±0.099)kg·m-3]and oxidation ditch process[(0.396±0.025)kg·m-3],which had a superior level of low-carbon operation.The carbon intensity of the various components of small and medium-scale WWTPs was as follows:biological treatment(58.7％)＞sludge dewatering+deodorisation(17.9％)＞deep treatment(17.3％)＞pre-treatment(6.1％);the biological part accounted for 51.5％,53.9％,and 73.1％of the total carbon intensity of the three processes,respectively.In addition,the influent COD concentration and COD/TN had significantly positive(path coefficients of 0.584 and 0.5)and negative(path coefficient of-0.416)impacts on the direct carbon emissions(N2O and CH4,respectively),and the influent concentrations of TN,BOD5,and TP had significantly positive effects on the indirect carbon emissions(electricity consumption)and indirect carbon emissions(material consumption),with path coefficients of 0.078,0.537,and 0.5,respectively.Carbon reduction in small and medium-scale WWTPs can be carried out by reducing carbon intensity,decreasing carbon operation levels,and strengthening government management.
维普
万方数据