Construction and demolition waste (CDW) accounts for 30% to 40% of the total amount of waste in China. CDW is usually randomly dumped or disposed in landfills and the average recycling rate of CDW in China is only about 5%. Considering there is big challenge in adoption of circular economy in CDW industry in China while related research is still limited, we conduct the CDW management analysis through 3R principle. Existing policies and management situations were investigated and analyzed based on the reduction, reuse and recycle principles. Results reveal that primary barriers of reducing CDW in China include lack of building design standard for reducing CDW, low cost for CDW disposal and inappropriate urban planning. Barriers to reuse CDW include lack of guidance for effective CDW collection and sorting, lack of knowledge and standard for reused CDW, and an underdeveloped market for reused CDW. As for recycling of CDW, key challenges are identified as ineffective management system, immature recycling technology, underdeveloped market for recycled CDW products and immature recycling market operation. Proposals to improve the current situation based on 3R principle are also proposed, including designing effective circular economy model, reinforcing the source control of CDW, adopting innovative technologies and market

Purpose The study objectives are twofold: (i) combining the life cycle sustainability assessment (LCSA) framework and the multicriteria decision-making (MCDM) methodology for sustainability assessment and (ii) determining the most sustainable scenario for bioethanol production in China according to the preferences of the decision-makers/stakeholders. Methods Life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (SLCA) are combined to collect the corresponding criteria data on environmental, economic, and social aspects, respectively. The study develops a novel SLCA method for quantifying the social criteria. The decision-makers/stakeholders can use linguistic terms to assess these criteria, and fuzzy theory is used to transform the linguistic variables into real numbers. Once the sustainability assessment criteria are determined, the study develops an MCDM method that combines the analytic hierarchy process (AHP) and the VIKOR method to prioritize the alternatives. The AHP is used to determine the criteria weights that are a prerequisite when using VIKOR; the VIKOR method is then used to determine the sustainability sequence of the scenarios. Results and discussion The study's proposed method investigates an illustrative case about three alternative bioethanol production scenarios (wheat-based, corn-based, and cassavabased): The prior sequence (based on the sustainability performances) in descending order is cassava-based, cornbased, and wheat-based. The proposed methodology results allow Chinese decision-makers/stakeholders to select the most sustainable scenario among many alternatives. The proposed methodology is generic, meaning that further alternatives can be studied and the most sustainable option can be ultimately determined.Conclusions The main study contribution is to test the combination of an MCDM methodology and LCSA for sustainability decision-making by studying three alternative pathways for bioethanol production in China. The proposed method feasibly enables the decision-makers/stakeholders to find the most sustainable scenario to achieve their objectives among various alternatives.

No abstract

A deep learning approach coupling the Tree-LSTM network and back-propagation neural network for predicting the octanol–water partition coefficient.