A crucial first step in transforming problematic waste management into sustainable integrated systems is comprehensive planning and analysis of environmental and socio-economic effects. The work presented here is a Life Cycle Assessment (LCA) that addressed the environmental performance of prospective development pathways for the municipal solid waste (MSW) management system in a large urban area, i.e. Campo Grande, Brazil. The research built on data and expanded the main development pathway proposed in the municipalities integrated waste management plan, which covers a period of 20 years (2017-2037). The system progression was assessed for milestone years (5-year intervals) considering projections of future population and waste generation growth, as well as addressing the development of surrounding systems, such as energy production. Results reveal that the rather conservative planned development pathway, which is largely based on gradual increase in selective collection, could successfully counter negative environmental externalities that would otherwise materialize due to increasing waste generation. A second, more ambitious, pathway with additionally scheduled actions to treat mixed MSW and upgrade certain treatment technologies (e.g. from composting to anaerobic digestion of collected organics), was used to illustrate a potential range for significantly higher impact reduction and even positive externalities, given a zero burden approach before waste generation.