Urine diversion

Urine diversion, also called urine separation or source separation, refers to the separate collection of human urine and feces at the point of their production, i.e. at the toilet or urinal. Separation of urine from feces allows human waste to be treated separately and used as a potential resource. Applications are typically found where connection to a sewer-based sanitation system is not available or areas where water supplies are limited. Urine diversion, also called urine separation or source separation, refers to the separate collection of human urine and feces at the point of their production, i.e. at the toilet or urinal. Separation of urine from feces allows human waste to be treated separately and used as a potential resource. Applications are typically found where connection to a sewer-based sanitation system is not available or areas where water supplies are limited. To achieve urine diversion, the following technical components are used: waterless urinals, urine diversion toilets, urine piping to a urine storage tank (or to a sewer) and a reuse or treatment and disposal system for the urine. Urine diversion toilets may, or may not, mix water and feces, or some water and urine. They never mix urine and feces. A toilet used to facilitate the separation of human waste products is called a urine diversion toilet or UDT. The bowl usually has two separate receptacles which may or may not be flushed with water. If flushed, the toilet is usually referred to as a urine-diversion flush toilet or UDFT. If not flushed, it is a dry toilet with either drying or composting for the feces. If the collected feces are dried, it is called a urine-diverting dry toilet or UDDT (also called urine-diversion dehydration toilet). If the collected feces are composted, it is called a urine-diverting composting toilet. Some technologies applied as part of an ecological sanitation concept use urine diversion. There are several commercially available urine diversion toilets (UDT) and urine diversion dry toilets (UDDT). Many look like a conventional sit-down or squat toilet and the bowl is divided into two sections, with the front section collecting urine and the rear section feces. Reasons for urine diversion which are relevant for all types of UD systems: Reasons for keeping urine and feces separate in a dry toilet compared to a pit latrine can be to: Urine diversion takes advantage of the anatomy of the human body, which excretes urine and feces separately. In a UDDT, the urine is drained via a basin with a small hole near the front of the user interface, while feces fall through a larger drop-hole at the rear. This separate collection – or ‘source separation’ – does not require the user to change positions between urinating and defecating, although some care is needed to ensure the right position over the user interface. Female users may find that some urine may enter the vault during normal operation. This is typically a small amount and does not significantly affect the function of the toilet. Separate treatment of the two types of waste is justified since urine is nearly sterile and low in pathogens, provided an individual is healthy. This means that urine can be readily utilized as a fertilizer or discharged with less risk to community. Human feces, on the other hand are high in pathogens, including up to 120 viruses and need to be treated well before it can be safely used in agriculture. The main two treatment methods are composting and drying. When feces are used without composting, it is called night soil, and is very smelly.