基于生命周期的惰性建筑垃圾再生技术选择与集成管理系统评价模型

As the vast majority of construction & demolition waste (CDW), the inert CDW like concrete, bricks, mortar, tiles and ceramics will be sent to C&D landfills. Its continuously increasing quantity has placed great burden on the finite landfill space and environment. The most effective way to reduce the waste problem is agreed in recycling the debris. At present, the recycling of inert CDW shows obvious externalities, therefore traditional economic analysis will be unable to provide comprehensive decision basis for improving the recycling of inert CDW. There is a need for systematic approach to investigate the efficiency of recycling inert CDW to achieve the integration between economic and environmental effects. This study will present a life cycle-based framework to determine the optimal inert CDW waste recycling alternative. In addition, the framework will also be used to make a comprehensive evaluation of approaches to inert CDW management in Xining City. The framework consists of an environmental life cycle costing (ELCC) and a financial life cycle costing (FLCC) using the same unit of account under the same system boundaries. The ELCC is thus here represented as the external cost estimates based on an application of the impact pathway approach, enhanced by earlier experience from extensive Life Cycle Assessment (LCA), and the willingness-to-pay approach as a supplementary for those impacts without actual measurable market. The FLCC involves all costs for fulfilling the functional unit(s) other than when those environmental effects have an economic impact on the system studied to make sure that no double counting takes place. A mass flow model will be used to account for all of the incoming and outgoing mass for each process in inert recycling systems as well as an inert CDW management system, then the material flow data can incorporate with the FLCC and ELCC data associated with each management activity to provide an economic analysis for proposed CDW management scenarios with different degree of recycling options. This study will ascertain the relationship between the evaluation results and the grade of original technical performance of inert CDW, which is useful for evaluating the range of application of each recycling solution. We will reveal the inherent laws to which the recycling rate varies with inert CDW management options. The objective is that the life cycle-based method can act as a decision-support tool for policies innovation to improve the recycling activities of inert CDW.

作为建筑垃圾废物流的核心成分，惰性建筑垃圾通常采用填埋方式处置，导致土地占用、环境影响等问题。再生利用是解决这些问题的有效方式。但现阶段，惰性建筑垃圾的再生利用过程具有显著的外部性，致使传统的经济分析无法为改进惰性建筑垃圾的再生利用提供明确的决策依据。我们拟构建生命周期评价（LCA）与生命周期成本分析（LCC）集成的系统分析模型，采用影响路径法和支付意愿法，将环境影响转换成环境成本，LCC则用于分析系统边界内的经济成本。我们将该模型用于比较惰性建筑垃圾再生技术和分析西宁市惰性建筑垃圾管理，拟阐明再生技术方案评价结果与惰性建筑垃圾本身技术性能间的关系，揭示再生利用率与惰性建筑垃圾管理系统评价结果间的关系，为合理选择惰性建筑垃圾再生技术、改进惰性建筑垃圾管理决策和政策制定提供依据。

作为建筑垃圾废物流的核心组分，由混凝土、砂浆、砖瓦、陶瓷、玻璃等构成的化学活性低、无害、存在明显外部性导致回收市场缺乏的惰性废弃材料，其资源利用是缓解建筑垃圾问题的重中之重。项目实地调查了西宁市及周边建筑垃圾再生方法和工艺，并采用文献分析方法，详细调查了目前国内外惰性建筑垃圾的再生方法和途径，绘制了惰性建筑垃圾再生路径图，确定了纳入惰性建筑垃圾再生技术选择与集成管理系统构建所需分析的方法和工艺；利用地理信息系统（Geographic Information System，GIS）软件、谷歌影像，以及现场实地调查数据，采用自下而上的方法，详细测算了西宁市主城区（城东、城中、城西和城北四区）1968年- 2017年施工、拆除废弃物的产生量与组成，预测了西宁市2018年- 2067年施工、拆除废弃物的产生量与组成，并就建筑寿命对惰性建筑废弃物产生量的影响进行了敏感性分析，得到了西宁市惰性建筑废弃物的时空演变情况；采用基于活动（过程）的方法，将LCA与LCC设置在统一的系统范围内，通过收集各活动（过程）的资源和能源消耗、环境排放和直接活动成本，按照活动归集建立物理单位和直接成本清单数据库，分别从环境影响的中点类型和终点类型，量化分析框架中影响类型的环境成本，核算惰性建筑垃圾生命周期综合成本；分别核算了废弃混凝土、墙体材料和未分类收集惰性废弃物（混合物）三种废弃材料不同再生技术的综合成本，提出了一种成本-性能再生技术评判模型，计算了三种废弃材料不同再生技术的成本-性能系数，分析了三种废弃材料不同再生技术的成本-性能变化规律，确定了当前三种废弃材料适宜的再生技术方案；利用材料流分析模型，构建了西宁市惰性建筑垃圾集成管理系统，核算了系统内惰性建筑垃圾产生、运输、各种再生途径、最终填埋处置的质量流和经济流，就西宁市惰性建筑垃圾现状、不同再生率进行了情景分析，核算了现状系统综合成本，模拟分析了不同再生率管理系统综合成本，提出了建筑垃圾管理的政策建议。