Municipal Solid Waste (MSW) management is an important challenge in developing countries, where the recovery of recyclable materials is often made in informal conditions by waste pickers. How to pass from a deficient waste management system to an improved one (and what does it means) and how to integrate waste pickers in the formal system are therefore crucial questions. This thesis was aimed at the enhancement of the waste management of Tandil, a city of the Buenos Aires province (Argentina), especially concerning the situation of local waste pickers. On the one hand, our approach combined a local transformation and action-research framework, the Latin American Extension, with transformational approaches used to solve societal persistent complex problems, mainly transdisciplinarity. On the other hand, we generated basic knowledge regarding the local waste management system. The thesis combines three published articles with several introductory chapters in which we justify the adopted approach and we describe the actions that supported and followed the generation of the articles’ knowledge. In the first article, we worked with Argentinian researchers and students to apply a standardized methodology of waste characterization under budget constraints to obtain the generation rate per category of waste. We identified several specificities in our results related to the high loss of mass during the picking analysis. We associated it with a typical habit of our region, i.e. the consumption of yerba mate, a supposition that needs further research. In the second article, we used the information of waste generation in combination with other primary and secondary sources with two main purposes: 1) to calculate indicators related to formal and informal waste recovery; 2) to evaluate how the system was functioning regarding the drivers of integrated sustainable waste management (ISWM). Our results showed that, as in many cities of developing countries, informal recovery is higher than formal recovery. Moreover, we analysed the inadequacy of current local recovery strategies regarding the legislation in force. With this information and through different interventions along several years, we supported the formation of the local waste pickers cooperative. In our last article, we analysed how the integration of waste pickers evolved in Tandil, regarding the local situation and some important changes occurred at the national level. Along our work, we tried to involve the local government in co-creation dynamics to co-construct a vision of the future waste management system. However, we never achieved this objective.