铁路桥梁建设泥浆废水处理-机制砂生产组合工艺碳排放核算及综合评估

Carbon Emission Accounting and Comprehensive Evaluation for Combination Process of Slurry Wastewater and Mechanized Sand Production in Railway Bridge Construction

桥梁建设过程中产生的泥浆废水由于高悬浮物(SS)和高pH值较难处理达标,钻孔桩基产生的钻渣可用来生产砂石骨料,但需要大量的水资源。本研究设计了8种近零排放泥浆废水处理与砂石骨料生产组合工艺,基于生命周期理论,构建组合工艺碳排放核算模型和综合评估方法。案例分析结果表明:化学混凝-pH值调节-棒磨机制砂生产组合工艺生命周期碳排放量最大,为2 974.29 tCO_(2e),机械分离-立轴式冲击破碎机制砂生产组合工艺碳排放量最小,约为1 038.75 tCO_(2e)。应用熵权-优劣解距离法(熵权-TOPSIS法)综合评估8种组合工艺,发现机械分离-pH值调节-棒磨机制砂生产组合工艺与最优工艺贴近度最高。该研究结果支持铁路桥梁建造泥浆废水处理和钻渣综合利用组合工艺设计。

The slurry wastewater generated during bridge construction is difficult to treat and meet the standards due to its high suspended solids(SS)and high pH value.The drilling slag generated by drilling pile foundations can be used to produce aggregates,but this process requires a large amount of water.In this investigation,8 near zero discharge combination processes of mud wastewater treatment and aggregate production were designed.Based on the life cycle theory,carbon emission accounting model for the combined process has been constructed,and a comprehensive evaluation method has been established.The case analysis results show that the combined process of chemical coagulation-pH adjustment-rod grinding mechanism sand production has the highest carbon emissions during its lifecycle,approximately 2974.29 tCO_(2e),while the combined process of mechanical separation-vertical axis impact crushing mechanism sand production has the lowest carbon emissions,about 1038.75 tCO_(2e).Entropy weight-Technique for order preference by similarity to ideal solution(Entropy weight-TOPSIS)comprehensive evaluation method was applied to evaluate 8 combination processes,and it was found that mechanical separation-pH regulation-rod grinding mechanism sand production combination process has the highest degree of closeness to the optimal process.The research results will support the design of a combined process for mud wastewater treatment and comprehensive utilization of drilling slag in railway bridge construction.