Building toilets with less water consumption

I am a first year engineering student from South Africa. I would like to know how we can build toilets with less water consumption.

Low-flush toilets

All toilets manufactured after 1993 are called ULFT (Ultra Low Flush Toilets). They use 1.6 gallons each flush. Toilets that were manufactured in 1979 or earlier use 5 gallons per flush, and from 1980 to 1993 use 3.5 gallons per flush.
Taken from indoor tips at Water Wise, http://ag.arizona.edu/cochise/waterwise/

Low-flush toilets: research into plumbing requirements.
A nice article taken from Source Weekly, 10 Mar 2003, http://www.irc.nl/source/item.php/1383
Includes contact information and related sites.

You can also find information on water savings achieved by water-saving devices – including the low-flush toilet- at: EPA - Water - How to Conserve Water and Use It Effectively - http://www.epa.gov/OW/you/chap3.html
EPA is the US Environmental Protection Agency.
(to convert US gallons to litres use http://www.convertit.com/Go/ConvertIt/Measurement/Converter.ASP)

You may also want to consider alternative solutions, such as composting toilets.

A good introduction to ecological or environmental sanitation can be found on the sanitation connection website at http://www.sanicon.net/titles/topicintro.php3?topicId=17

The following articles provide good information on toilets using less or no water:

• Environmentally-friendly hygienic dry sanitation technology, WEDC conference paper by Farley, M. and Kilbey, S. (1999), http://www.lboro.ac.uk/wedc/papers/25/029.pdf
• Faq sheet on on-site sanitation latrines, prepared by CREPA, Burkina Faso, http://www.irc.nl/page/10371
• Practical Action (formerly The Intermediate Technology Development Group (ITDG) provides a Technical Brief on composting toilets. This is an introductory fact-sheet presenting basic practical information. http://www.itdg.org/docs/technical_information_service/compost_toilets.pdf

Finally, in your region, the following organisations are worthwhile to contact:

• CSIR in South Africa, is also active in this field. One of their publications is on Urine-diversion ecological sanitation systems in South Africa. Abstract available at: http://www.csir.co.za/plsql/ptl0002/PTL0002_PGE015_PRODUCT?PRODUCT_NO=7051119
• The Water Research Commission in Pretoria. They are publishing lots of technical publications. One of them is on composting latrines: Scott, S. ; Water Research Commission -Pretoria, ZA (1998). An evaluation of the enviro loo composting latrine in an informal settlement area in Greater Johannesburg. (WRC report; no. KV112/98). Pretoria, South Africa : Water Research Commission.
  For an online available version, see the WEDC conference paper "Evaluation of composting latrines": http://www.lboro.ac.uk/departments/cv/wedc/papers/23/groupb/banister.pdf