Prepared for Water, Sanitation and Health. Written by Dr. Rosalind Stanwell Smith and reviewed by the Water and SanitationProgramme, World Bank and the Water, Sanitation and Health Unit (WSH), World Health Organization (WHO)WHO/WSH/WWD/TA.8© 2001–2003, 2002 WHOSanitation: Controlling problems at sourceIntroductionWherever humans gather, their waste also accumulates. Progress in sanitation and improved hygiene has greatly improved health, butmany people still have no adequate means of disposing of their waste. This is a growing nuisance for heavily populated areas, carryingthe risk of infectious disease, particularly to vulnerable groups such as the very young, the elderly and people suffering from diseasesthat lower their resistance. Poorly controlled waste also means daily exposure to an unpleasant environment. The build up of faecalcontamination in rivers and other waters is not just a human risk: other species are affected, threatening the ecological balance of theenvironment.The discharge of untreated wastewater and excreta into the environment affects human health by several routes:By polluting drinking waterEntry into the food chain, for example via fruits, vegetables or fish and shellfishBathing, recreational and other contact with contaminated watersBy providing breeding sites for flies and insects that spread diseasesPoor nutrition from loss of important fish protein sources due to environmental pollutionUsed carefully, wastewater and excreta are valuable resources and increasingly important for agriculture and aquaculture, particularlyin countries with insufficient water resources. Climate change, threatening water supplies in both water rich and water poor countries,has raised the issues of wastewater use worldwide. This fact sheet focuses on:People and waste: the size of the problem1.Wastewater and excreta: hazards or resources? including diseases linked to waste2.How sanitation prevents disease3.Sanitation Options4.Using human waste, overcoming barriers5.People and waste: The size of the problemWorldwide 2.4 billion people do not have access to basic sanitation: they lack safe means of disposal of excreta and waste waterDespite continued efforts to promote sanitation 40% of the world's population is still without basic sanitation. This number does nottell the whole story, sanitation coverage is often much lower in rural areas than in urban areas. For example, in Africa 84% of urbanbut only 45% of rural residents have access to basic sanitation. The numbers are similar in Asia where 78% of urban and 31% of ruralresidents have access to basic sanitation (WHO, 2000). In many cases, improving sanitation can be as simple as installing awell-designed ventilated improved pit latrine (VIP) or composting latrine. However, in other cases, improving sanitation will be morechallenging, particularly in rapidly growing urban slums. Moreover, while building improved sanitation facilities is a crucial healthintervention, the full health benefits will not be realized without proper use and maintenance of the facilities and good personal anddomestic hygiene (Carr and Strauss, 2001).Sanitation facilities interrupt the transmission of faecal-oral disease at its most important source by preventing human faecalcontamination of water and soil. Poor waste disposal practices are responsible for a significant proportion of the world's infectiousdisease burden. Diseases due to poor water supply, sanitation, and personal and domestic hygiene cause 4.0% of all deaths and 5.7% ofall disability or ill health in the world. This burden is not distributed equally; waterborne illnesses predominantly affect the poor andthe young. However, when basic water, sanitation, and hygiene interventions are applied, waterborne illnesses can be effectivelyreduced. Low cost interventions such as composting latrines can be used to reduce the transmission of many diseases.Municipal sewage is a mixture of human excreta and household wastewater that is transported via pipes to a treatment or disposalWHO | Sanitation: Controlling problems at source http://www.who.int/water_sanitation_health/sanitproblems/en/print.html1 of 10 2/10/2009 7:37 AMpoint. In many areas, municipal sewage is often mixed with industrial waste. Sewerage systems are common in industrialised countriesand often occur in urban areas of less-industrialised countries. In some regions very little wastewater receives treatment before it isdischarged into the environment. In Africa, virtually no wastewater receives treatment before it is discharged. In other regions, rates oftreatment are not much better, for example, in the Latin America and Caribbean Region only 14% of wastewater is treated, while inAsia approximately 35% of wastewater is treated before it is disposed of in the environment (WHO 2000b). Problems in wastedisposal are not confined to less-industrialised countries. Industrialized countries also need to improve their sewage, excreta, andsludge management practices. In North America 10% and in Europe 34% of wastewater is not treated before it is discharged into theenvironment (WHO, 2000b). In the United States of America, the number of detected waterborne disease outbreaks and the number ofaffected individuals per outbreak has increased since 1940 (Hunter, 1997). Similarly, water quality monitoring of major Europeanrivers indicates that average coliform levels - the organism present in human, animal and bird excreta - have been steadily increasing fordecades (Meybeck et al. 1990).Currently, water-borne sanitation systems typically use 50 to 100 litres of water to remove 1-1.5 litres of human excreta per person perday (Jönsson, 1997; Van der Ryn, 1995). Moreover, most of this water is used to remove urine (urine makes up 90% of the volume ofexcreta) which poses little threat to human health (Esrey, 2000). In this type of system, a small amount of faeces then contaminates alarge amount of water and nutrients that could be useful locally are washed away into other areas (or removed at great expense in atreatment system) where they concentrate. High levels of nutrients cause environmental damage and exacerbate the growth ofpotentially toxin-producing algae. Clearly, sustainable sanitation alternatives are needed.Toilets and latrines: a basic right and an essential way of controlling sanitation problems at sourceIn examining the larger issues of waste disposal, we should not forget the role played by the humble latrine. Far more people
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