Human waste

Human waste, also known as human excreta, is a waste type usually used to refer to byproducts of digestion, such as feces and urine. There are many different ways in which human waste can be collected, treated and disposed or reused, depending on the sanitation system that is in place, e.g. starting with the type of toilet that is being used. The situation differs vastly across the world, with many people in developing countries having to resort to open defecation for lack of other options where the human waste is deposited in the environment, while others can use flush toilets where the human waste is mixed with water, transported and treated in sewage treatment plants. Children's excreta can be disposed of in diapers in municipal solid waste but on a worldwide scale it is also often dumped into the environment, leading to public health risks.

Terminology
The term "human waste" is used in the general media to mean several things, such as sewage, sewage sludge, blackwater - in fact anything that may contain some human feces. In the stricter sense of the term, human waste is in fact human excreta, i.e. urine and feces, with or without water being mixed in. For example, dry toilets collect human waste without the addition of water.

Health hazard
Human waste is considered a biowaste as it is a good vector for both viral and bacterial diseases. It can be a serious health hazard if it gets into sources of drinking water. The World Health Organisation (WHO) reports that nearly 2.2 million people die annually from diseases caused by contaminated water. A major accomplishment of human civilization has been the reduction of disease transmission via human waste through the practice of hygiene and sanitation, which can employ a variety of different technologies.

Methods of processing
Methods of processing depend on the type of human waste. If it is sewage, then sewage treatment can be used to treat it. If it is sewage sludge, then it may undergo sewage sludge treatment. If it is fecal matter from dry toilets, it may undergo composting.

The amount of water mixed with human waste can be reduced by the use of waterless urinals and composting toilets and by recycling greywater. The most common method of human waste treatment in rural areas where municipal sewage systems are unavailable is the use of septic tank systems. In remote rural places without sewage or septic systems, small populations allow for the continued use of honey buckets and sewage lagoons (see anaerobic lagoon) without the threat of disease presented by places with denser populations. Honey buckets are used by rural villages in Alaska where, due to permafrost, conventional waste treatment systems cannot be utilized.

Uses
Human waste in the form of wastewater (sewage) is used to irrigate and fertilize fields in many parts of the developing world where fresh water is unavailable. Sri Lanka's International Water Management Institute (IWMI) published a report which suggests that there is great potential for wastewater agriculture to produce more food for consumers in urban areas, as long as there is sufficient education about the dangers of eating such food uncooked.

Human waste that has been treated by a hot composting process can safely be used to improve the soil for food crops.