中美典型污泥处理处置工程能耗和碳排放比较分析

COMPARATIVE ANALYSIS ON ENERGY AND CARBON EMISSION OF TYPICAL SLUDGE TREATMENT PROJECTS IN CHINA AND THE UNITED STATES

中美两国污水处理规模大、碳排放基数高,污泥的处理与处置是污水处理厂碳排放的重要组成部分,合理的污泥管理策略是未来污水厂碳减排的关键。实地调研了中美6个大型典型污水处理厂的污泥处理设施和污泥处置路径,分析了中美两国不同典型的污泥处理处置工艺能量回收和碳排放的表现特征。结果表明:在不考虑碳补偿的情况下,中美6个污水处理厂中,华东A(中温厌氧消化+脱水+填埋/土地利用)、华东B(脱水+填埋/焚烧)、华东C(脱水+焚烧)、Hyperion(高温厌氧消化+脱水+农用)、OCSD(中温厌氧消化+脱水+农用)和Blue plains(热水解+中温厌氧消化+脱水+农用)的污泥处理处置路线的碳足迹分别为1410,1881,1914,471,402,405 kgCO_(2)/t DS。考虑能源回收和资源化利用产生的碳补偿效果,中美6厂污泥处理处置的净碳排放分别为984,1681,1941,-183,-240,-315 kgCO_(2)/t DS。中美6个污水厂碳补偿率分别为30.2%、10.6%、0%、138.9%、159.7%和177.9%。污泥厌氧消化和产物土地资源化利用是碳减排的关键,提升污泥有机质含量能够强化碳补偿效应,该研究结果可为我国污水处理厂低碳转型、污泥处理处置的无害化、减量化和低碳化提供参考。

China and the United States have large wastewater treatment and high carbon emission scale. The carbon emission from sludge treatment and disposal is an important part of the total carbon emission of sewage treatment plants. A reasonable sludge management strategy is the key to future carbon emission reduction of sewage treatment plants. In this paper, the sludge treatment facilities and paths of six typical wastewater treatment plants in China and the United States were investigated on-site, and the performance characteristics of energy recovery and carbon emission of different typical sludge treatment processes in China and the United States were analyzed. The results showed that, without considering carbon offset, among the six wastewater treatment plants in China and the US, the carbon emission of East China A(mesophilic anaerobic digestion+dewatering+landfill/land use), East China B(dewatering+landfill/incineration), East China C(dewatering+incineration), Hyperion(thermophilic anaerobic digestion+dewatering+agricultural end-use), OCSD(mesophilic anaerobic digestion+dewatering+agriculture end-use) and Blue plains(thermo hydrolysis+mesophilic anaerobic digestion+dewatering+agricultural end-use) were 1410, 1881, 1914, 471, 402, 405 kg CO_(2)/t DS, respectively. Considering the carbon offset effect caused by energy recovery and resource utilization, the net carbon emission from sludge treatment and disposal in the six WWTPs were 984, 1681, 1941,-183,-240,-315 kg CO_(2)/t DS, respectively. The carbon emission offset efficiency of six WWTPs in China and the United States was 30.2%, 10.6%, 0%, 138.9%, 159.7% and 177.9%, respectively. Sludge anaerobic digestion and land utilization of its product were the keys to carbon emission reduction, and increasing the organic matter content of sludge could enhance the carbon offset effect. The research results could provide basis and reference for the low-carbon transformation of WWTPs in China and the harmless, reduced and low-carbon treatment of sludge.