Otimização no transporte e disposição final dos resíduos urbanos: uma proposta de readequação no plano estadual de resíduos sólidos do RN

Abstract

The New Legal Framework for Basic Sanitation (Law Nº 14.026/2020) in Brazil defined new deadlines for the eradication of open-air dumps as an alternative of final disposal of solid waste. In the state of Rio Grande do Norte (RN) many municipalities still use openair dumps for final disposal of solid waste, due to the high cost of implementing sanitary landfills. Aiming to solve this problem, public consortiums emerged as a way of meeting legal requirements regarding the final disposal of solid waste by the municipalities. The consortiums are formed by a group of municipalities, one of which is destined to receive the landfill, and then transshipment stations are distributed among the municipalities as a way of facilitating the transport and temporary storage of solid waste generated by all the municipalities in the consortium. That said, this research aims to propose, for three subregions in Rio Grande do Norte, a better allocation of transshipment stations. The method developed consists of the mathematical modeling of the problem as a Facility Location Problem and the use of combinatorial optimization techniques, Integer Linear Programming, more precisely, for its solution. The solutions obtained by the model present an average total cost for all sub-regions that is approximately 6,7% lower when compared to the solutions initially proposed by the State Secretariat for the Environment and Water Resources (SEMARH) of RN, through the State Plan for Integrated Solid Waste Management, enabling thus significant cost savings in the process of final disposal of solid waste by the municipalities. The efficiency of the proposed model is proven in all sub-regions, with emphasis on Vale do Assú sub-region, where it enabled a 52.8% reduction in investment costs, with the installation of just 5 ETTs, while the plan suggested the installation of 13. The proposed solutions contribute to rapid implementation of state plans by the public initiative, as they have high quality in terms of costs, in addition to making it possible to accelerate the decision-making process regarding the installation of transshipment stations.