Simple-Tech Solutions for Sustainable Waste Management

This thesis originated from a desire to explore the issue of solid waste, the appropriate management of which continues to represent a privilege for the few, in order to investigate alternative cost-effective solutions aimed at promoting access of the population worldwide to sustainable waste management systems. The work had a particular focus on landfilling from a holistic point of view, investigating environmental, technical and economical sustainable solutions in terms of landfill management and emissions control. The thesis work was developed over a three-year period in four steps. In the first step, activities focused on the study and gaining a better understanding of the need for a global approach to waste management, with the application of identical concepts and knowledge throughout the world and envisaging appropriate and sustainable technical solutions, not only in environmental terms but also in economic (they should be low cost) and technical terms (they should easy to construct, operate and maintain). Further to carrying out literature reviews and taking part in a series of International Conferences where waste management in DCs was discussed in detail, a field stage abroad, on the Ivory Coast, proved of fundamental importance for the development of this first step. In the second step, the sustainability of landfills was studied and analyzed by considering the tools which could be implemented to control long-term emissions in the case of Municipal Solid Waste (MSW) landfilling. Research activities were focused on the comprehensive study of bioreactor landfills, comparing (using literature data) lab scale applications of different types of bioreactors, and evaluating the advantages and disadvantages. Having conducted a qualitative analysis of the main types of bioreactor landfills, landfill sustainability was quantified using a first order kinetic model for the COD and ammonia removal processes. Amongst the different sustainable landfill alternatives, semi-aerobic landfill represented a viable option meeting environmental, technical and economical sustainability requirements. During the third step of the thesis work, semi-aerobic landfills were studied in detail in order to identify innovative solutions to optimise the design and management of the system under different situations. The fourth step of research activities was inspired by a need to identify cost-effective solutions to solve the key issue in landfilling sustainability: leachate treatment. An innovative alternative potential solution based on exploiting the versatility and voracity of Black soldier fly (BSF) larvae was investigated. The adaptability of larvae to leachate, the treatment performance and the quality of the biomass rich in fats and proteins were initially assessed. Additionally, the potential of proteins and fats to be conveniently converted into commercial resources, such as animal feed and biodiesel was evaluated. During this fourth step, for three months at the beginning of the 2019, a research stage was specifically organised at the KUET University, Bangladesh to investigate the potential of mangroves for use in the phytotreatment of landfill leachate, exploiting the high resistance to salinity of these plants. A preliminary study has been carried out using as a comparison other tropical plant species such as Canna indica.