Optimization Model Development For Recyclable Municipal Solid Waste Collection Network And Emperial Study

With fast urbanization and the improvement of people’s living standards,the volume of municipal solid waste produced is increasing rapidly,which greatly impedes the sustainable development of cities.Promoting the recycling and reuse of municipal solid waste is one of the most important way to respond this challenge,and the establishment of municipal solid waste recycling network is the key to improve the management level of municipal solid waste.Under such circumstances,this study aims to develop an optimization model for urban recyclable waste collection network to simulate the optimal number,location and scale of recycling stations and regional recycling centers(RRCs).Shanghai,a mega city that is leading China’s garbage sorting and the "combined network" system will be further selected as the case area,so that policy suggestions for promoting the construction of urban recyclable waste collecting system of Shanghai can be proposed.The amount and spatial distribution of municipal solid waste and recyclable wastes was predicted first in this study.Then the location optimization model was further established by adopting the P-中值method to determine the optimal number,scale and location of regional recycling center.Two optimization objective was considered,namely,achieveing the lowest total cost and the lowest CO2 emission.The results show that the amount of municipal solid waste in Shanghai will reach 9.92 million tons in2020.From the perspective of spatial distribution,urban areas had higher municipal solid waste intensity compared with rural areas due to their higher population density and consumption level.Therefore,the optimized RRCs were almost located around urban areas.The optimized number,scale and location of regional recycling centers were selected from 22 candidate RRCs based on Shanghai’s local development plans.If the target is to achieve the lowest cost,the optimal number of regional recycling centers is 12,and the corresponding total cost is about 120 million yuan/year.If minimum CO2emission is taken as the optimization objective,the optimal number of regional recycling centers should be 9,and the corresponding total annual carbon emission should be 9404 tons/year.In addition,when unit transportation cost and unit scale cost change,the optimal result will also change.For example,the number of optimal RRCs will increase with the increase of unit transportation cost or the decrease of marginal unit scale cost.Finally,some policy implications on the construction of renewable resources collection and transportation system in Shanghai were puts forward,and limitations of this model were discussed.