1.1 Background

Human waste excreta can be defined as waste products of the human digestive system and the human metabolism, namely feces and urine. It is a vector for both viral and bacterial diseases and can be a serious health hazard if it gets into sources of drinking water. As part of a sanitation system that is in place, human waste is collected, transported, treated and disposed of or reused by one method or another, depending on the type of toilet being used, ability by the users to pay for services and other factors. The disposal systems in place differ vastly across the world, with many people in developing countries having to resort to open defecation where human waste is deposited in the environment, for lack of other options. People in developed countries tend to use flush toilets where the human waste is mixed with water and transported to sewage treatment plants. Children’s excreta can be disposed of in diapers and mixed with municipal solid waste. Diapers are also sometimes dumped directly into the environment, leading to public health risks.


Human excreta and the lack of adequate personal and domestic hygiene have been implicated in the transmission of many infectious diseases including cholera, typhoid, hepatitis, polio, cryptosporidiosis, ascariasis, and schistosomiasis. The World Health Organization (WHO) estimates that 2.2 million people die annually from diarrheal diseases and that 10% of the population of the developing world are severely infected with intestinal worms related to improper waste and excreta management (Murray and Lopez 1996; WHO 2000a). Excreta and wastewater generally contain high concentrations of excreted pathogens, especially in countries where diarrheal diseases and intestinal parasites are particularly prevalent. Therefore, for maximum health protection, it is important to treat and contain human excreta as close to the source as possible before it gets introduced into the environment. Human excreta-transmitted diseases predominantly affect children and the poor. Most of the deaths due to diarrhea occur in children and in developing countries (WHO 1999). Proper excreta disposal and minimum levels of personal and domestic hygiene are essential for protecting public health. Safe excreta disposal and handling act as the primary barrier for preventing excreted pathogens from entering the environment. Once pathogens have been introduced into the environment they can be transmitted via either the mouth (e.g. through drinking contaminated water or eating contaminated vegetables/food) or the skin (as in the case of the hookworms and schistosomes), although in many cases adequate personal and domestic hygiene can reduce such transmission.

Safe disposal of excreta can be accomplished in many ways, some requiring water, others requiring little or none. Regardless of method, the safe disposal of human fecaes is one of the principal ways of breaking the fecal–oral disease transmission cycle. Sanitation is therefore a critical barrier to disease transmission. The method of waste excreta disposal in communities is an important determinant of health status. In Nigeria, the major methods include; pit latrine, water closet, VIP latrine and open defecation.