Desarrollo de un sistema de soporte a la decisión para optimizar la planificación y gestión de los residuos sólidos urbanos en zonas insulares, basado en dinámica de sistemas y teoría de la decisión multicriterio (Fuzzy Topsis)

Laburpena

The improvement of the municipal solid waste (MSW) management is an essential issue for the sustainability of any territory, and even more critical in tourist islands. The Balearic Islands and the Canary Islands constitute interesting case studies since they can be considered as almost closed systems. Insularity implies a triple impact from the socio-economic, political and environmental point of view. Proper MSW management requires the availability of waste storage and treatment infrastructures for its minimization, reuse, recovery and elimination, to be able to meet the goals established by the European Union in terms of achieving reuse or recycling 55% of MSW in 2025, 60% in 2030 and 65% in 2035. Besides, it is mandatory to reduce landfilling to 10% by 2035 and the organic waste generation by 30% in 2025 and 50% in 2030. Currently, both archipelagos are far from these goals. In the Balearic Islands, the recycling ratios only reached 15.81% and in the Canary Islands 11.18% in 2018. The objective of this research has been to obtain a methodology and a series of prospective tools that provide instruments to improve the planning and management of MSW in island areas. Econometric models are applied to determine the key variables that affect the generation of waste, the fuzzy TOPSIS method to find the best alternative (waste treatment) of the multi-criteria decision problem posed, reducing uncertainty since the information to be analysed is obtained from the qualitative and quantitative way. Finally, System Dynamics and Scenario Analysis are applied, since both are effective methods for studying dynamic conditions and changes in complex systems. Systems Dynamics helps us to predict the future behaviour of certain variables under different scenarios and to apply different strategies for their improvement, improving decision-making and strategic planning. The econometric models were validated using statistical tests, such as normality in the residuals, autocorrelation, multicollinearity, heteroscedasticity, Granger causality, among others, allowing to find the main “driving forces” of the generation of waste and to identify which ones had the most significant influence on the same. For the System Dynamics model validation, the verification tests of the structure, verification of the parameters and the test of extreme conditions on the parameters were used. The expected forecasts for the trend base scenario until 2035 without applying improvements to the current system, show low rates of recovery, separation, recycling and incineration; On the contrary, applying the strategies established in the projected alternative scenarios, in the short and long term, would obtain more consistent improvements, but for this, it is necessary to implement new, more sustainable management models to curb and control the generation of waste. The main conclusion of this research is that current waste management models in these study areas must be improved. The high levels of generation are the consequence of unsustainable consumption habits, a limited domestic market and an economy highly dependent on the tourism sector. The result is that generation rates increase, and waste continues to be diverted to uncontrolled landfills. In summary, the management of MSW in island areas presents a series of problems that can be analysed using the methodology and decision-support tools developed in order to improve their management.