Types of Research
This brief reviews the literature and empirical evidence on waste extraction and treatment in the developing world. The brief assesses the quantity and quality of research supporting key components of program theory related to the extraction of sludge from on-site sanitation facilities and pre-disposal transport. In general, we find few empirical studies that directly evaluate the assertions of the program theory. Most of the evidence in the literature that addresses the target components of program theory is based upon case studies or general observational and experiential assertions by sanitation experts. Where appropriate, we have identified evidence in the literature according to whether case studies or informal observations formed the basis of the conclusion.
The purpose of this literature review is to provide qualitative and quantitative examples of technologies, constraints and incentives for efficient waste treatment and reuse in Sub-Saharan Africa and Southeast Asia. We present relevant case studies and expert observations and experiences on the nutrient content in urine and feces, contaminants frequently found in untreated sludge and wastewater, waste treatment technologies that may be relevant for low-income countries, risks associated with waste reuse, benefits to resource recovery in agriculture. We further discuss reasons for waste treatment failures, including urbanization, observations on challenges with market-driven reuse in less developed countries, and examples of net-positive energy facilities in Europe and the United States. Much of the evidence presented in the literature relates to wastewater treatment processes or the sludge produced from wastewater treatment as opposed to untreated fecal sludge. However, examples of risks, failures, and opportunities for raw sludge treatment and reuse are discussed when available. In some cases, empirical evidence or case studies were not available for developing countries and alternatives are presented. Overall we found the empirical evidence on waste treatment and reuse in developing countries is quite thin.
Water supply and sanitation is the responsibility of sub-national state governments under the Indian Constitution. At present, the national government sets water supply and sanitation policy while states plan, design, and execute water supply schemes accordingly. Furthermore, while state governments are in charge of operation and maintenance, they may pass the responsibility to village or district levels. Given the highly decentralized provision of water and sanitation services, there is no autonomous regulatory agency for the water supply and sanitation sector in India at the state or national level. This report reviews literature on India’s urban sanitation policy. The methodology includes Google, Lexis-Nexis, and University of Washington Library searches, searches of two major Indian newspapers, and searches of websites and blogs sponsored by non-governmental organizations. Sources also include the India Sanitation Portal, a forum on sanitation in India used by governmental and nongovernmental organizations, and WASH Sanitation Updates, a sanitation news feed with considerable material on India. We find that urban sanitation policy, as embodied in the National Urban Sanitation Plan of 2008, remains focused on decentralized approaches. Our research reveals no evidence of a change in official policy, nor evidence suggesting that government sanitation programs conflict with official policy.
Limited sanitation infrastructure, poor hygienic practices, and unsafe drinking water negatively affect the health of millions of people in the developing world. Using sanitation interventions to interrupt disease pathways can significantly improve public health. Sanitation interventions primarily benefit public health by reducing the prevalence of enteric pathogenic illnesses, which cause diarrhea. Health benefits are realized and accrue to the direct recipients of sanitation interventions and also to their neighbors and others in their communities. In a report to the United Nations Development Programme (UNDP), Hutton et al. (2006) estimate that the cost-benefit ratio of sanitation interventions in all developing countries worldwide is 11.2. This literature review summarizes the risks of inadequate sanitation to public health and presents the empirical evidence on the public health benefits of complete, intermediate and multiple factor sanitation interventions. We find that complete or improved sanitary systems can offer concrete public health benefits by reducing exposure pathways to a variety of infectious diseases contained in human feces and wastewater. Substantial complementary economic gains are also predicted to accrue as a result of providing increased sanitation. In addition, community-wide sanitation interventions seem to offer the greatest promise for reducing pathogenic health risks from feces.
Without availability and access to a variety of foods, populations in the developing world are suffering from deficiencies in iron, zinc, iodine, vitamin A, and other micronutrients in addition to deficiencies in energy and protein. Supplementation and fortification programs have demonstrated effectiveness, but there is an increasing interest in potentially more sustainable solutions via agricultural interventions. The review examines the literature regarding agricultural interventions and pathways to diet diversification and whether desired nutritional outcomes are achieved. We find a strong sentiment that agricultural interventions can improve dietary diversity, and that dietary diversity can improve nutrition and related health outcomes. The programs with demonstrated ability to improve nutrition outcomes are most often cross-cutting interventions, borrowing from the agriculture, nutrition, and public health traditions. While these multi-platform programs can be costly to evaluate and difficult to implement, the evidence supports their potential to create sustainable quality-of-life improvements in target regions. The pathways by which agricultural interventions achieve impact are not fully clear, however. The greatest knowledge gaps are directly related to the lack of integration between program design and evaluation. Many evaluations are based on small sample sizes, lack control groups or baseline data, are subject to selection bias, or face other challenges to rigorous statistical analysis.