• image
  • image
  • image
  • image
  • image
Previous Next

Questions to the Water Sector Reform Programme Sanitation Team Nairobi Kenya

How did you hear about this document?

We got information about the book form our GIZ colleagues based at GIZ head office in Germany. Which parts of it did you find most useful? The whole book is very useful. We found chapters 3) Design of the urine diversion toilet seat, squatting pan, urinal and the toilet cubicle 4) Faeces vault design and function 5)Urine collection system design and function 6) Additional design considerations and 7) Disposal, treatment and reuse of faecal matter and urine very useful in our work since we were designing UDDTs for urban low income areas of Kenya.

If you could give any advice for a future edition, what would it be?

The Use of UDDT in Urban low income areas should be more elaborated especially with regard to best practices in sludge reuse /disposal. Knowledge and good practices applied on large scale still missing worldwide.

Should the authors have put more attention on certain issues?

The books document the UDDT very well. The use of UDDT in dense urban areas needs more attention and more successful best examples done on a large scale. This may be tailored to meet the demands for different regions since the dense urban areas vary from region to region (Africa, Asia and South America). The spatial setup varies also within a country.

Who in your opinion should read this document?

This document has very important information on UDDT. All those stakeholders involved in improving rural and urban sanitation should read it. This includes relevant government departments, NGOs, Water Services Regulatory Authority, Water Services Trust Fund, and National Environmental Authority.

Contact details of authors:

Christian Rieck: Christian. This email address is being protected from spambots. You need JavaScript enabled to view it.

Heike Hoffmann: This email address is being protected from spambots. You need JavaScript enabled to view it.

Elisabeth von Muench: This email address is being protected from spambots. You need JavaScript enabled to view it.

If you wish to apply for hard copies (small numbers can be sent free of charge), please contact: Christian Rieck at GIZ in Germany: This email address is being protected from spambots. You need JavaScript enabled to view it.

7 Questions:The authors on planning of the new publication, building and maintaining UDDTs, beneficiaries of the publication etc :

Why did you decide to write yet another document about UDDTs, and how long did it takeYou?

When we started this work, we were not planning a new publication but merely wanted to update an existing publication by GTZ (now GIZ) called “Technical Datasheet of UDDTs”, which was written in 2005.We worked on revising this document over   the course of 2009 and 2010, but realized that a major overhaul was needed. This took us another two years (2011 and 2012) to complete. The end result is a completely new document which has undergone an intensive, International review process. The names of the International reviewers are listed in the Acknowledgement section.

How much practical experience do the authors have with building and maintaining UDDTs?

Christian Rieck’s practical experience with UDDTs stems from the time he worked in Nairobi for the GTZ Water Sector Reform Program (2006 to 2010), on a project funded by the European Union and Sweden, where UDDTs were built for 10,000 users in rural areas and schools. More than 1000 double-vault UDDTs were implemented via CBOs and the Water Services Trust Fund in South Nyanza, Western Kenya and other provinces of Kenya. One of the other authors, Heike Hoffmann, has extensive experience in building UDDTs in Peru

Where about 800 have been built under her guidance in the Coastal, Andean and Amazon regions. She works for a private company called Rotarian do Brasil and the consulting company AKUT. Currently, AKUT is working within a GIZ program which is working together with Peruvian water and sanitation utilities. She is responsible for the integration of service model for “dry sanitation” into the urban sanitation management, with the aim of offering an adequate sanitation service in urban areas without sewers as well.

Historical development

The earliest documented dry toilets with urine separation were installed in multi-storey houses in Yemeni towns and were, until recently, used continuously for hundreds of years. The UDDTs with double dehydration vaults that we know today were originally designed around 1950 in the Kanagawa Prefectural Public Health Laboratory in Japan and further developed in Vietnam in the 1960s as a means of increasing the hygienic safety of excreta reused in agriculture.1

Since the 1990s, modifications of this design have been promoted in countries like Mexico, Guatemala, El Salvador, India and Sweden. Ventilation pipes in the faeces vault were gradually integrated and allowed for the installation of UDDTs inside houses. More recently, prefabricated ceramic or plastic UD squatting pans and pedestals have become available on the market, generally increasing the durability and perceived prestige associated with the system. The design was further adapted in India and West Africa to accommodate anal cleansing with water, by including a separate anal cleansing pan with a drain to divert wash water into a dedicated disposal or treatment system.


According to the Joint Monitoring Program (JMP), approximately 2.5 billion people lack access to improved sanitation facilities, with 1.1 billion still practicing open defecation (UNICEF and WHO, 2012). Knowledge and practice of critical hygiene behaviors, such as hand washing after toilet use, are also widely lacking. Consequently, the ingestion of faecal pathogens from contaminated food and water resources as well as faecal- oral transmission are a leading cause of disease and preventable death, especially in children under five years.The effects of inadequate sanitation, hygiene and resulting diarrheal disease are dramatic: in 2010, the

World Health Organization (WHO) reported that worldwide the impact of diarrheal disease on children is greater than the impacts of HIV/AIDS, tuberculosis and malaria, combined. Due to their relative affordability and simple and waterless operation, pit latrines are common in developing and transitional countries. However, pit latrines can spread faecal contamination to water resources, especially in associated with faecal sludge removal or excavation of new pits when emptying is not feasible.

Technology Review of Urine-diverting dry toilets (UDDTs)


This technology review deals with a type of toilet designed specifically for dry excreta management called the urine- diverting dry toilet (UDDT). It is a sanitation system for households and public facilities as well. The functional design elements of the UDDT are: source separation of urine and faeces; waterless operation; and ventilated vaults or containers for faeces storage and treatment. UDDTs may be constructed with two adjacent dehydration vaults or one single vault with interchangeable containers. This publication offers a complete overview of UDDT functions, design considerations, common operation and maintenance issues and generalised installation costs. Its focus is on applications in developing countries and countries in transition, although UDDTs are also applicable in developed countries.


The UDDT technology was originally promoted in connection with safe reuse of excreta. However,the primary focus of UDDT implementation has gradually shifted from that of excreta reuse to the broader objective of creating an odourless, dry and versatile toilet that is applicable across wide range of geographic and economic contexts. Many successful examples of largescale UDDT programmes, such as those found in Lima, Peru and eThekwini (Durban), South Africa, dispose of treated excreta instead of reusing it, as it is considered more practical, convenient or acceptable to the users.




Current Issue: Africa Water & Sanitation & Hygiene March-April 2017 Vol.12 No.2