Research On Optimization Of MSW Recycling Network Design

At present, municipal solid waste (MSW) has become a chronic problem thathinder healthy developement of most cities in China. There are many problems existin our MSW recycling mode compared to other countries, such as low recyclinglevels, single treatment etc, which lead to many cities are actively exploring newMSW recycling mode. View of the similarity of national situation between Chinaand Brazil, Sai Puli recycling mode in Brazil has a high reference value. From theliterature reading, MSW recycling network design always separately consider asLocation Transportation Problem (LTP) or Vehicle Routing Problem (VRP), fewstudies consider both together, nor consider MSW resources reuse. In that context,this paper focuses on a decision problem that how to build a MSW recycling networkunder mixed collection and centralized sorting mode.This paper introduces the research background and reviews the current status ofMSW recycling practice and research at home and abroad. According to theproblems in domestic practice and research, the author puts forward the maincontents of this paper and describes the significance of this research.MSW recycling logistics and the principle, content, elements of building therecycling network are all analyzed based on clarifying the concept of MSW, and thentypical models for MSW recycling network design and MSW collection vehiclerouting are also introduced to lay the theoretical foundation for mathematicalmodeling in this paper.This paper proposes to desigin a MSW recycling network with sorting centerthat can realize MSW separation and recycling by learning from Brazilian Sai Pulirecycling mode. Due to the issue of MSW recycling network design involvesproblemes of facilities location and collection vehicle routing optimization, amathematical model for multi-echelon MSW recycling network is finally constructedthrough combining both typical mathematical models together and abstractingvarious assumptions into mathematical constraints. The main characteristics ofMSW recycling network model constructed in this paper are comprehensiveconsidering the problems of MSW separation and recovery, typical facility locationand MSW collection vehicle routing. Considering the NP-hard character of themodel, a hybrid algorithm is proposed to solve the LRP model by serial operating Tabu search and genetic algorithm in this paper. TS algorithm is used to solve VRPunder all location plan of sorting center and save the results, and GA is is used tosolve solve facility location problem. In the process of evaluate GA solutioninvolving VRP, the results of TS saved is directly called.A numerical example is utilized to test the proposed model and algorithm.Experimental results show the feasibility of the model and the excellentcharacteristics of the proposed algorithm. Then, sensitivity analysis of collection andtransportation cost, algorithm parameters are conducted. Experimental results showcollection&transportation cost greatly impact on the total cost, while algorithmparameters do not affect the total cost significantly. This implies that the proposedalgorithm is robust to changes in parameters.