Département Assainissement, Eau et Déchets pour le Développement

Solid waste management is a growing global challenge, especially in developing countries such as Vietnam, where rapid urbanisation and inadequate infrastructure intensify environmental and public health risks. Landfilling is one of the most environmentally harmful waste disposal methods. However, it remains widely used in many countries because of its cost-effectiveness. Proper disposal of solid waste is a significant priority for reducing environmental pollution. Selecting suitable landfill sites requires consideration not only of physical and environmental aspects but also of economic and social factors. In Phu Yen Province, located in south central Vietnam, solid waste management faces growing challenges in solid waste management. Limited landfill infrastructure and poor operational standards are already impacting public health and the environment. Moreover, with existing landfills approaching the end of their usable lifespans, identifying new, appropriate sites has become an urgent priority. This study introduces a novel approach that integrates a geographic information system (GIS)-based multi-criteria decision analysis (MCDA) with a fuzzy analytic hierarchy process (Fuzzy AHP) to enhance landfill site suitability assessments. This study's approach enables a holistic evaluation of economic, environmental, topographical, and social factors, thereby ensuring a more comprehensive decision-making process. The findings reveal that 45 % of the study area is very highly or highly potential for landfill sites, 28 % is of medium potential, 27 % is of low or very low potential, and 25.7 % of the existing landfill locations pose significant environmental and human health risks. A spatial distribution map obtained from a comprehensive analysis incorporating economic, social, environmental, and topographical factors helped identify potential future sites for solid waste disposal in Phu Yen Province. The methodology demonstrated in this study is highly transferable and can be applied to other low- and middle-income countries that face similar waste management challenges.

Current models for understanding the spatial diffusion of innovation exhibit significant limitations when it comes to explaining how transformative innovations in sectors of the foundational economy travel between cities and countries. Transformative innovations in infrastructure sectors like water, energy, or waste management are typically not reducible to single products or technologies but rely on a set of complementary organizational, social, policy, and demand-side innovations. Their spatial diffusion thus requires nonlinear socially embedded institutionalization processes that include regulative, political, and cultural changes, extending well beyond the knowledge- and market formation dynamics emphasized in conventional diffusion models. This article develops a conceptual model that specifies the socio-technical contextualization and de-contextualization processes that take place every time an innovative infrastructure innovation travels between places. It disentangles the spatial complexities involved in the packaging of social and technical elements into coherent configurational templates that enable the spatial diffusion of transformative innovations. We apply our framework to a case study of the diffusion of circular district-scale sanitation systems (CDSS) in Europe, drawing on fifty-four expert interviews and an extensive database of secondary material. Our findings show how a template for CDSS was continuously optimized and standardized through spatially scattered experiments, pilot and demonstration projects, and high-profile lighthouse initiatives spread across Europe. Based on our findings, we elaborate a three-stage phase model for the institutionalization of configurational templates. The model provides inroads for assessing diffusion challenges in other sectors where transformative innovation is intimately coupled with socio-technical reconfiguration.

Household post-consumer flexible plastic (PCFP) consisting of films and bags is currently unattractive for recycling because of contamination. The success of recycling strategy depends on the selection of compatibilizers and fillers; however, their influence on the properties of resulting products has not been systematically reviewed. This review will analyze their impact on the mechanical properties of resulting composites and provide fundamental guidelines for the selection of compatibilizers and fillers. The addition of virgin polymer or copolymer improves the elongation at break of the composite, but it is significantly below that of original flexible plastic. Polyolefin grafted with maleic anhydride appears to be the best option for enhancing both tensile strength and modulus, achieving improvements of approximately 28.0% and 22.0%, respectively. Further enhancements can be achieved with the addition of natural fibers such as jute, corn, and piassava. For instance, jute fiber can increase tensile strength and modulus by approximately 30.6% and 160.8%, respectively. Nanomaterials also hold great potential; incorporating graphene into recycled high-density polyethylene can enhance tensile strength and modulus by approximately 56.4% and 125.0%, respectively. Clearly, composite production represents the most viable option for PCFP recycling, where the selection of compatibilizers and fillers should play a decisive role.