Archaeological evidence from the Indus Valley civilization shows that flush toilets have existed since around 3000 BC, albeit in a different form. But it is obviously not suitable in areas with underdeveloped water and sewage networks.

Excrement will pollute food and water sources and cause intestinal diseases. 1.5 million children under the age of five are killed worldwide every year, which is higher than the death toll caused by AIDS and malaria.

At present, many rural areas in China do not have a domestic sewage pipe network, which leads to the use of traditional dry toilets and double urn toilets in rural areas. This not only results in poor hygiene conditions but also causes significant environmental and water pollution.

Many rural households do not have bathrooms in their main rooms, and the toilets are located in the courtyard, which makes it difficult for the elderly, children, and those with limited mobility to use the toilet. In addition, outdoor toilets are also extremely inconvenient in cold winters in northern rural areas.

Basic principles

Most human feces are organic matter, and the use of microorganisms to decompose organic matter is called "biodegradation". After the gradual decomposition of organic matter, intermediate metabolites that can enter the TCA pathway or serve as synthetic metabolic raw materials are produced, which are then converted into small molecule organic and inorganic decomposition products and microbial cells. Extracellular enzymes break down large molecules into small molecules that can be absorbed by cells. Dehydrogenation and oxidation of small molecules: producing acetyl CoA that can enter the TCA cycle. Acetyl CoA enters the TCA cycle and is oxidized into CO2 and H2O in the respiratory chain to achieve complete elimination treatment.