基于城市生活污水系统全生命周期的直接碳减排路径研究

Research on Direct Carbon Emissions Reduction Path Based on Whole Life Cycle of Municipal Domestic Sewage System

当前,对污水产生、收集、处理、尾水排放及再生利用全生命周期直接碳排放的关注较少,大多聚焦污水处理中的间接碳排放。为准确把握污水系统碳排放及碳减排的关键,促进新时期污水系统绿色低碳高质量发展,从污水处理的发展史出发,研究了污水全生命周期的碳排放及碳减排路径。结果表明:污水处理发展史是一部碳减排史,污水全生命周期过程是碳排放过程,污水产生源头(化粪池)及污水收集管网中存在更多的碳排放,控制厌氧生境CH_(4)等高温室效应气体直排空气是当前碳减排的关键。源头节水、取消或及时清掏化粪池、减少溢流、提升污水收集率、适度控制污水厂规模(5~10万m^(3)/d为宜)、保持污水高速低水位运行、优化以干化焚烧为主的污泥处置方式、强化尾水再利用等措施具有较好的碳减排效果。

The current studies about carbon emissions of municipal domestic sewage systems are mainly focused on indirect carbon emissions during treatment processes,instead of their direct carbon emissions during the whole life cycle including sewage produce,collection,treatment,discharge,and recycle use.By learning from the development history of municipal domestic sewage systems,this research has studied the crucial definition and pathways about carbon emissions and carbon emission reduction on a whole-life-cycle base,for further developments under the concept of“Green,Low carbon and High Qualities”.The results have showed that development history of municipal domestic sewage system has been equivalent to development history of its carbon emissions.The whole-life-cycle process of sewage has been equivalent to carbon emission process of sewage.It has showed there have been more carbon emissions during sewage produce(especially septic-tank)and collection more than treatment and discharge,so the key pathways for carbon emission reduce have been determined to decreasing greenhouse gas produced by anaerobic habitat treatment and their direct emissions,i.e CH _(4).It is concluded that there have been many methods having relative better effects for carbon emission reduce,such as water conservation,removing septic-tank or cleaning on a schedule,decreasing sewage overflow,increasing sewage collecting rate,reasonable scale of sewage treatment plant(5~10×10^(4) m 3/d),keeping high speed and low water level during treatment,enhancing sludge disposal methods(mainly drying incineration)and discharge reuse,etc.