Urine diversion
Urine diversion
Urine diversion refers to the separation of urine from feces at the point source, i.e at the toilet or outhouse. A toilet fixture used to help facilitate the separation is called a urine diversion toilet or UDT. The bowel has two separate compartments which may or may not be flushed with water. If flushed, the toilet is usually referred to as a UD toilet or UDT. If not flushed, it is a urine diversion dry toilet or UDDT. Separated feces may be composted or dried. If dried, the overall system is called a urine diversion dehydration or dessication toilet or UDDT.
Most forms of ecological sanitation are based upon urine diversion.
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.
Principle
Separate treatment of the two is justified since urine is nearly sterile and low in pathogens provided an individual is healthy.[1] This means that urine can be readily utilized as a fertilizer or discharged with less risk to community.[2]
Feces on the other hand are high in pathogens, including up to 120 viruses and should either be composted for several months, or dried and burned as a biofuel.[3] When feces are used without composting, it is called night soil. Its use in some areas has been so ingrained that entire cultures will not eat any vegetables or fruits unless they are thoroughly cooked.[4]
When composted, ash and/or sawdust are usually added to speed the process. Of the two, ash decreases microbial activity faster.[5] Dehydration and conversion into a biofuel is typically accomplished by exposure to dry air and/or solar heat.
Some toilets integrate composting or dessication as part of an entire system as in an installation located at an inn in Khuvsgul National Park in Mongolia.[6]
Other toilets focus more on removal of urine so feces can be composted at a different location as in the floating toilet.[7][8]
Whether the feces are handled on site or hauled to another location, the weight and volume of material is reduced by separating out urine. Additionally, treatment is simplified and faster.[9] Some web sources cite keeping urine within the overall compost to be beneficial by adding nitrogen, however, urine is mainly water and this increases moisture content of the compost increasing composting time till this moisture is removed.[10][11] Urine diversion is the main reason one manufacturer of composting toilets claims their product is less problematic then toilets that don't.[12]
UD Toilets (UDT), and UDD Toilets (UDDT)
There are several commercially available. Many look like a conventional sit down or squat toilet and the bowel is divided into two sections. The front section collects urine and the rear section feces. One manufacturer of a UDDT describes their product as a "UD Dry Toilet".[13] More elaborate versions feature separate flushing with water in each compartment. More basic versions are essentially an outhouse with a divider and one or two containers below. One container is typically used in floating toilets and urine immediately discharged to local waters.
Owing to limited water supplies, NASA started in May 2009 to utilize a UDD toilet to recycle urine into drinking water.[14]
Examples of UDD toilets/systems around the world
- A prime driver of this type of approach to sanitation is an organization called Women in Europe for a Common Future (WECF). The WECF and local partners have built more than 20 urine diverting dry toilet (UDDT) buildings for schools, as demonstration projects in different countries of the Eastern Europe, Caucasus and Central Asia (EECCA) region.[15]
- Georgia (country) - First indoor UDD toilet opened in school for socially vulnerable children by WECF partner RCDA The construction was financially supported by the Dutch Ministry of Foreign Affairs and UNICEF and was carried out in cooperation with Women in Europe for a Common Future (WECF)[16]
- Mindanao, Philippines - The first urine-diversion dehydration toilet of Mindanao was inaugurated in November 2005, there are already 60 units completed in this southern island of the Philippines while further 60 units are presently under construction or in the planning phase, respectively.[17]
- Cambodia - Lien Aid has assisted with the development and implementation of floating toilets that utilize UDD in a project called “River of life”[18]
- Rwanda - UDDT at a public toilet and a school near Kigali[19]
- China - in 2003 reportedly had 685,000 operating UDD toilets spread out among 17 provinces[20]
- Boating - Chris Melo, sailboat resident and nautical engineer, cites 9 reasons to convert from conventional nautical toilets that store waste in black water tanks, or immediate discharge it overboard, to a UDD composting toilet[21] Two competing manufactures for nautical use call their products Nature's Head and the Air Head Toilet.[22]
- Camping - Leave no trace is not only a philosophy but a necessity in areas where human waste left behind would not decay naturally. There are now portable UDD toilets that allow feces to be collected and packed out. Only near pathogen free urine is left behind.[23]
See also
External links
References
- ^ http://weblife.org/humanure/chapter7_2.html Web article on pathogens that in turn mainly came from book, Appropriate Technology for Water Supply and Sanitation, by Feachem et al., World Bank, 1980.
- ^ http://www.ncbi.nlm.nih.gov/pubmed/18578152 Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa, Lead author: Mnkeni PN, April 2008
- ^ http://ecosanservices.org/pdf/UDD-ToiletsTraining%20material.pdf UDD-Toilets and urine management
- ^ http://weblife.org/humanure/chapter7_2.html Web article on pathogens that in turn mainly came from book, Appropriate Technology for Water Supply and Sanitation, by Feachem et al., World Bank, 1980.
- ^ http://www.ncbi.nlm.nih.gov/pubmed/19303763 Comparing microbial die-off in separately collected faeces with ash and sawdust additives, Author Niwagaba C et al, 2009
- ^ http://www.khovsgolinn.com/Khuvsgul%20Inn%20Ecosan%20Pilot.pdf Khuvsgul Inn, Ecosan pilot-project, Khatgal Mongolia
- ^ http://washtech.wordpress.com/tag/urine-diverting-toilets/ Floating toilets for floating villages on Cambodia’s Tonle Sap lake
- ^ http://www.adb.org/Water/Photos/CAM/floating-toilets/Default.asp Sample Designs: Floating UDD Toilets, Asian Development Bank Website
- ^ http://www.cdc.gov/haiticholera/sanitation.htm CDC Document Potential sanitation solutions for emergency response, February, 2011
- ^ http://www.sswm.info/category/implementation-tools/water-use/hardware/toilet-systems/composting-toilets Composting toilets, by Dorothee Spuhler
- ^ http://mooseville.weebly.com/7/post/2011/07/composting-is-easy.html Composting is easy, by Daisy Gerber, July 2011
- ^ http://ecovita.net/news/ How to fix a leaking (other brand) composting toilet, by July 2009
- ^ http://www.eqc.kyoto-u.ac.jp/ud-toilet/top_en.html UD Dry Toilets
- ^ http://www.nasa.gov/home/hqnews/2009/may/HQ_09-096_Recycled_Water_Go.html NASA Gives Space Station Crew 'Go' to Drink Recycled Water, May 2009
- ^ http://sanitationupdates.wordpress.com/tag/urine-diverting-toilets/ Sustainable and safe school sanitation brochure, 2009
- ^ http://www.wecf.eu/english/articles/2010/06/rcda-schooltoilet.php First Indoor UDD Toilet Georgia opened in school for socially vulnerable children by WECF partner RCDA
- ^ http://puvep.xu.edu.ph/snews/ecological_sanitation/uddt_mindanao/ UDDT Update Mindanao: 60 Units Already Completed
- ^ http://washasia.wordpress.com/category/regions/east-asia/cambodia/ UDD and floating toilets in Cambodia
- ^ Rwanda - UDDT at a public toilet and a school near Kigali http://www.flickriver.com/photos/gtzecosan/sets/72157627175799611/
- ^ http://www.iwc-berlin.de/medienpool/iwc_m77_61000000012/iwc_20071011140736_1_840856.pdf Water and Sanitation related Activities, German Gesellschaft für Technische Zusammenarbeit(GTZ)
- ^ http://ecovita.net/news/wp-content/uploads/2009/07/NaturesheadOnBoat2.pdf
- ^ http://forum.woodenboat.com/showthread.php?114077-Nature-s-Head-vs.-Air-Head-Toilet Wooden Boat Forum
- ^ http://www.flickr.com/photos/gtzecosan/2921708370/ Photo of Foldable camping UDD toilet by Separett (Sweden)