A Coordinated Framework for the Optimization of Municipal Solid Waste Management

The lack of collection and processing infrastructure for waste management in developing countries is an overwhelming concern. Moreover, the growing generation of waste makes this problem even more complex. Specifically, in Mexico, the waste generation per day is approximately 0.13 MT. Landfill space is becoming increasingly constrained in some large urban centers where there are no other processing technologies, thus the use of open dump systems might be needed. The Mexican environmental protection agency (SEMARNAT) has reported that in 2012 from all the waste generated in Mexico, 72% was disposed of at sanitary landfills and regulated sites, while 23 % was disposed of at open dumps and the rest 5% was recycled. Considering these issues, we propose to optimize municipal solid waste management systems using a coordinated framework. The framework accommodates distinct stakeholders involved in the system, such as suppliers of waste, consumers of waste and derived products, and providers of transportation and processing services. The proposed optimization formulation seeks to maximize the collective profit and to balance supply and demand for waste and derived products. To achieve this, in the proposed framework, the stakeholders submit bids to a market coordinator that solves the optimization problem to find the allocations and clearing prices that guarantee that no stakeholder loses money. The framework also allows the monetization of environmental impacts, such as open dump disposal. Therefore, a taxation scheme to account for this environmental impact is evaluated. To illustrate the applicability of the presented approach, a municipal solid waste (MSW) system in Mexico was analyzed as a case study. Results show how taxation incentivizes the provision of services for all stakeholders. Furthermore, the minimum tax required to avoid diverting waste to open dump systems was identified.