Pour flush Toilet
Just like a cistern flush toilet, the pour flush toilet has a water seal that prevents odours and flies from coming back up the pipe. Water is poured into the bowl to flush the toilet of excreta; approximately 2 to 3 L is usually sufficient. The quantity of water and the force of the water (pouring from a height often helps) must be sufficient to move the excreta up and over the curved water seal.
Both pedestals and squatting pans can be used in the pour flush mode. Due to demand, local manufacturers have become increasingly efficient at mass-producing affordable pour flush toilets and pans.
The water seal at the bottom of the pour flush toilet or pan should have a slope of at least 25°. Water seals should be made out of plastic or ceramic to prevent clogs and to make cleaning easier (concrete may clog more easily if it is rough or textured). The S-shape of the water seal determines how much water is needed for flushing. The optimal depth of the water seal head is approximately 2 cm to minimize the water required to flush the excreta. The trap should be approximately 7 cm in diameter.
The water seal is effective at preventing odours and it is appropriate for those who sit or squat (pedestal or slab) as well as those who cleanse with water. It is only appropriate when there is a constant supply of water available. The pour-flush toilet requires (much) less water than a traditional cistern flush toilet. However, because a smaller amount of water is used, the pour-flush toilet may clog more easily and thus, require more maintenance.
If water is available, this type of toilet is appropriate for both public and private applications. Pour-flush toilets are adequate for almost all climates.
The pour flush toilet (or squatting pan) prevents users from seeing or smelling the excreta of previous users. Thus, it is generally well accepted. Provided that the water seal is working well, there should be almost no odours and the toilet should be clean and comfortable to use.
Operation & Maintenance
Because there are no mechanical parts, pour flush toilets are quite robust and rarely require repair. Despite the fact that it is a water-based toilet, it should be cleaned regularly to maintain hygiene and prevent the buildup of stains. To reduce water requirements for flushing and to prevent clogging, it is recommended that dry cleansing materials and products used for menstrual hygiene be collected separately and not flushed down the toilet.
MARA, D. (1996): Low-cost Urban Sanitation. United Kingdom: Wiley.
ROY, A.K.; CHATTERJEE, P.K.; GUPTA, K.N.; KHARE, S.T.; RAU, B.B.; SINGH, R.S. (1984): Manual on the design, construction and maintenance of low-cost pour-flush water seal latrines in India. United Nations Development Programme (UNDP) and World Bank. URL [Accessed: 01.06.2010]. PDF
TILLEY, E.; ULRICH, L.; LUETHI, C.; REYMOND, P.; SCHERTENLEIB, R.; ZURBRUEGG, C. (2014): Compendium of Sanitation Systems and Technologies (Arabic). 2nd Revised Edition. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag). PDF
This is the Arabic version of the Compendium of Sanitation Systems and Technologies. The Compendium gives a systematic overview on different sanitation systems and technologies and describes a wide range of available low-cost sanitation technologies.
In this manual existing, innovative and new technologies and approaches for excreta disposal in emergency situations are investigated. It provides practical guidance on how to select, design, construct and maintain appropriate excreta disposal systems to reduce faecal transmission risks and protect public health in emergency situations.
WAFLER, M. ; HEEB, J.; STAUB, A.; OLT, C. (2009): Pour-flush toilets with biogas plant at DSK Training Institute. Gujarat, India - Draft. Eschborn: Sustainable Sanitation Alliance (SuSanA). URL [Accessed: 25.04.2010]. PDF
The project described aimed at avoiding manual scavenging of faecal products and at improving the sanitation situation at the Navsarjan Vocational Training Institute. Now greywater is separately treated and reused in the garden while the urine and faeces (blackwater) are directly introduced into a biogas plant. Digested sludge is dried on basic drying beds and used as compost for the garden. UDDTs were also installed. The concept was implemented and evaluated for its social and cultural acceptability, sustainable and hygienic safety.
http://www.youtube.com [Accessed: 17.10.2013]
This is a lecture By Duncan Mara on Pour Flush Toilets for use in developing countries.