渗滤液处理过程碳排放核算及减碳路径探索

Carbon Emission Accounting and Carbon Reduction Path Exploration in the Process of Leachate Treatment

随着生活垃圾处理量逐年上升,垃圾渗滤液作为一种生活垃圾处理过程中产生的高有机负荷、高氨氮废水,处理过程能够产生大量碳排放。基于此,本研究采用排放因子法,构建了适合垃圾渗滤液处理过程碳排放的核算方法体系,以充实生活垃圾处理领域对渗滤液处理过程碳核算的研究,并为类似工程提供借鉴。该方法体系核算了渗滤液处理过程中CH_(4)和N_(2)O的直接排放以及由药耗和电耗带来的间接CO_(2)排放。基于该体系,本研究选择了8个典型渗滤液处理工程,核算并分析了3种渗滤液(焚烧渗滤液、低龄填埋渗滤液和老龄填埋渗滤液)处理过程产生的碳排放结构特征。核算结果表明:①垃圾焚烧渗滤液和低龄填埋渗滤液的碳排放特征相似,相比老龄填埋渗滤液,碳排放强度更高;焚烧渗滤液和低龄填埋渗滤液碳排放以直接排放为主,CH_(4)和N_(2)O直接排放占比高达80%;老龄填埋渗滤液碳排放以间接排放为主,电耗造成的间接排放占比达到37%。②垃圾渗滤液处理去除单位COD、TN造成的碳排放量与市政污水相近,其中渗滤液去除单位TN产生的碳排放量略高于市政污水,因此需要提高相关处理系统的碳排放效率。③相关性分析显示,吨水碳排放量与直接排放占比、单位TN碳排放强度、进水COD浓度、进水TN浓度等均呈显著正相关。研究显示,垃圾渗滤液的碳排放特征与市政污水相比存在差异,CH_(4)回收、提高能效和使用新型膜材料是渗滤液处理减排的可行路径,本核算结果可为其他垃圾渗滤液处理碳核算提供参考。

With the increasing amount of domestic waste treated year by year,leachate,a high organic load and high ammonia nitrogen wastewater produced during the domestic waste treatment process,can generate a large amount of carbon emissions during its treatment.However,there is currently a lack of an adapted method for accounting carbon emissions from leachate treatment.Based on this,this study adopts the emission factor method to construct an accounting method system suitable for carbon emissions from the leachate treatment process,in order to fill the gap in the field of domestic waste treatment.The results show that:(1)The carbon emission characteristics of waste incineration leachate and fresh landfill leachate are similar,and the carbon emission intensity is higher than that of aged landfill leachate.Carbon emissions from incineration leachate and fresh landfill leachate are mainly direct emissions,with CH_(4) and N_(2)O accounting for up to 80%of direct emissions.The carbon emissions from aged landfill leachate are mainly indirect emissions,with indirect emissions caused by electricity consumption accounting for 37%.(2)The carbon emissions caused by the removal of COD and TN per ton from leachate treatment are similar to those of municipal sewage treatment plants.Among them,the carbon emissions generated by the removal of TN per ton from leachate are slightly higher than those of municipal sewage,and it is necessary to improve the carbon emission efficiency of relevant treatment systems.(3)Correlation analysis shows that there is a significant positive correlation between carbon emissions per ton of treated water and several variables,including the proportion of direct emissions,carbon emission intensity per unit TN,influent COD,influent TN,and treatment process.The study indicates that the carbon emission characteristics of leachate from waste differ from those of municipal sewage.Methane recovery,improving energy efficiency,and utilizing new membrane materials are feasible pathways for reducing carbon emissions in leachate treatment.These accounting results provide a valuable reference for carbon accounting in other leachate treatment processes.