污泥预调理方式影响下市政污泥“深度脱水-干化-焚烧”碳排放

Carbon emissions of municipal sludge"deep dehydration-drying-incineration"processes under different sludge preconditioning methods

基于污泥深度脱水中试示范,根据联合国政府间气候变化专门委员会(IPCC)提供的方法,对比新型污泥生物裂解绿色预调理技术和常规化学药剂(铁盐+石灰)预调理方式下的污泥“深度脱水-干化-焚烧”处理处置工艺碳排放特性.结果表明,污泥经过两种方法预调理后,板框压滤污泥含水率均能降至60%以下,但压滤泥饼干质含量和干基热值差异明显.经生物裂解后的污泥干质含量比投加铁盐+石灰的污泥减少23.0%;同时,其污泥干基热值较投加化学预调理后的高32.1%.通过碳排放量计算,处理每立方米含水率为98%的污泥,基于生物裂解的污泥“深度脱水-干化-焚烧”处理处置工艺总碳排放为15.8kg CO_(2)eq/m^(3)RS,比基于化学预调理工艺的总碳排放量(27.1kg CO_(2)eq/m^(3)RS)低41.7%.

This study developed pilot-scale"deep dehydration-drying-incineration"processes for sludge treatment and disposal with two different preconditioning approaches,i.e.,novel sludge biolysis and the conventional chemical agent(iron salt+lime).Then,the carbon emission characteristics of these approaches were analysed and compared according to methods by Intergovernmental Panel on Climate Change(IPCC).The results showed that the moisture contents of dewatered sludge with the plate and frame filter press were both less than 60%no matter which preconditioning method was applied.However,the dry matter contents and the dry basis calorific values of the filter pressed sludges were significantly different.Specifically,the biolysed sludge showed 23.0%lower dry matter content and 32.1%higher dry basis calorific value as compared with that treated with chemical preconditioning.Based on one cubic meter of raw sludge(RS)with 98%water content,and the total carbon emissions of the sludge"deep dehydration-drying-incineration"process for sludge treatment and disposal with biolysis as pretreatment was 15.8kg CO_(2)eq/m^(3) RS,which was 41.7%lower than that with the chemical preconditioning process(27.1kg CO_(2)eq/m^(3) RS).