A Methodological Framework for Evaluating the Environmental Performance of Large-Scale Sanitation Systems in Developing Countries

It is 2014 and approximately 40% of the world population still has no access to adequate sanitary toilets. For these 2.6 billion people the problem is not only finding a safe and dignified place to defecate, but also trying to combat deadly diseases associated with the exposure to pathogens in feces left on the ground or near waterways. Improving sanitation is not only favorable to health, but also promotes dignity, economic benefits and environmental conservation. Although there have been numerous efforts to improve sanitation systems in the developing world, adoption rates and long term use are relatively low due to poor understanding of the multiple requirements for sustaining such systems such as environmental conditions and cultural habits. Quantifying and comparing the costs and benefits of these systems to the environment is one step in better informing decision makers in large-scale development projects, and thus facilitating the selection of sustainable sanitation systems. The research conducted puts forth a method to assess and hierarchically classify large-scale systems based on their environmental performance and context. The proposed method provides structured steps of environmental assessment and multiple-criteria decision analysis to compare and contextually evaluate the environmental implications of large-scale systems. A case study on specific sanitation systems in Cap-Haïtien, Haiti was reviewed to demonstrate and evaluate the framework. The study compared the use of urine-diversion toilets coupled with a collection system that diverts waste to a compost facility versus flush toilets connected to sewer systems with either endpoint to waste stabilization ponds or discharged into the environment without treatment. Overall, the results from this study show that the alternative involving diverting waste to a compost facility was preferred to the other alternatives for large-scale sanitation systems for Cap-Haïtien, Haiti; although there are specific conditions where it might not be. Various scenarios and analysis were developed to help provide some perspective into the results and conclusions of the methodology and the modeled case study.