Research On Optimization Of Medical Waste Recycling Network With Periodic Recycling Strategy

With the improvement of medical level, the growth of urban population as well as the improvement of the health care system, the discharge of medical waste increase substantially. Since medical waste carries with a large number of pathogenic bacteria, it will cause potential harm to the environment and human health if illegal discharged. According to the existing recycling policy, medical waste must be collected within 48 hours. If the recycling methods that medical units with large quantity of medical waste are recycled once a day and those units with small quantity are recycled once two days are adopted considering the recycling policy, recycling companies will further reduce transport cost and improve recycling efficiency. Existing medical waste recycling network don’t take period conditions into their consideration, medical waste are collected everyday no matter how different in their outputs.This article, based on recycling policy, built a network of medical waste that periodic recycling is considered. Also, the mathematical model and heuristic algorithm were constructed.This article first summarized research status of medical waste recycling, the optimization of reverse network and periodic vehicle routing problem, at home and abroad. It is concluded that, in China, the study on the reverse network optimization of medical waste is less, and the research on periodic vehicle routing problem is also rare. Then, the article emphasized on the design of network of medical waste considering periodic recycling, and structured the mathematical model to optimize the vehicle routes to reduce the total distance. Guided Local Search has the characteristics of good robustness, universality and high efficiency, so it is being used in this article. The algorithm adopted Genetic Algorithm structure instead of neighborhood to improve the search efficiency. Numerical example is used to verify the feasibility and validity of the algorithm by comparing the results with known optimal solution. Finally, the model and algorithm is applied to a realistic example of recycling of 260 medical collection transit points. When compared the results of periodical recycling strategy with the results of non-periodical recycling strategy, it is concluded that the model in this article can effectively reduce the travelling distance in the medical waste recycling.The model in this article belongs to single-type vehicle problem, while in realistic world, there will be multi-type vehicles recycling medical waste. Therefore, periodic and multi-vehicle routing problem and its application in the recycling of medical waste deserve further research.