Evaluation of innovative decentralized sanitation technologies in Ghana

Abstract

It is estimated that 2.5 billion people lack access to improved sanitation, and 90% of wastewater in developing countries is discharged into the environment without any treatment. However, the construction of sewerage systems and centralized wastewater treatment plants is neither an affordable nor appropriate solution for many areas. Therefore, an emphasis has arisen on decentralized sanitation technologies that treat waste on-site and recover resources that can be used to generate economic gains. Using a case study method and an evaluation matrix, this thesis evaluates the efficacy and scalability of several such innovative sanitation technologies. The decentralized technologies evaluated include the Clean Team Toilet, Microbial Fuel Cell Latrine, Biofil Toilet, Microflush Toilet, and the more traditional pour-flush toilet. Two semi-centralized technologies, the IMWI Fortifer pellets and Ashesi University's small-scale wastewater treatment system with anaerobic digestion, were studied as well. Case studies of these technologies were conducted in January 2014 in Ghana and involved surveys of users and interviews of service providers and their competition where possible. The evaluations were completed using this information and were guided by criteria on sanitation outcomes, business management, and technology categories. We conclude that the Biofil Toilet is the current gold standard for decentralized sanitation, although it is costly. The locally sourced Microflush Toilet is recommended for middle- and low-income families and small aid projects, for it functions similarly to the Biofil Toilet but is approximately one-fifth the cost. For large projects in densely populated areas, the Clean Team Toilet is recommended if a reuse for waste and safe disposal of biocide can be established. Other technologies require further development before they can be recommended for implementation and use.