Report 4 of 5: Vacu-tug - Kenya

Introduction

Worldwide roughly one billion people lack access to clean water and more than 1.7 billion do not have adequate sanitation. Poor sanitation practices are a major polluter of rivers and ground water resources. Every year millions of the world’s poorest people die from preventable diseases, such as typhoid and cholera, which are caused by the lack of safe, adequate water supplies and sanitation services. Hundreds more people suffer from regular bouts of diarrhoea, parasitic worm infections and vomiting caused by contaminated water. The lack of adequate sanitation for large sections of the urban population poses a threat to public health and to the environment.

As far as sanitation and general environmental well-being are concerned, one of the most serious consequences of rapid urban expansion is the growth of squatter settlements and slum areas in run-down city centres. In most of the cities in developing countries, especially in the low-income urban settlements, the collection and disposal of human excreta is a serious problem. Establishing waterborne sewerage systems in the unplanned areas of these cities is hampered by a multitude of limitations.

Pit latrines

Pit latrines of different kinds and bucket latrines are a common sanitation facility in many parts of African and Asian cities. The pit latrine is a hand dug pit in the ground with a squatting slab on top. It is lined with stones or bricks to prevent it from collapsing and a superstructure is built around it for privacy. The life of the pit latrine varies from 4 to 15 years, after which time it has to be emptied or a new pit has to be dug.

Pit latrines can be emptied using either manual or mechanical methods. Scoops and buckets are used to remove the more fluid type of waste while thicker sludge has to be dug out by hand. Mechanical methods revolve almost entirely round the use of vacuum trucks where atmospheric pressure forces the pit contents along a hose pipe into a vacuum tank.

The Vacu-tug pit latrine exhauster

The emptying of pit latrines is a major problem faced by the urban poor in developing countries. UNCHS (Habitat) together with Manus Coffey Associates carried out a project to find an appropriate technology to empty pit latrines, which led to the development of the Vacu-tug. The Vacu-tug is a small and sturdy vehicle, measuring 1 metre wide x 1.5 metres long, capable of emptying waste from a pit latrine and transporting it to a discharge site.

• It is a service affordable by the urban poor, with the capital cost affordable by entrepreneurs who can potentially develop a micro-enterprise, recovering the operational costs from the revenue generated.

• It is capable of accessing some of the most densely populated urban areas, with narrow and bumpy lanes, where conventional systems are unable to penetrate.

• It can be constructed, operated and maintained using local materials and skills.

• The technology is capable of transporting waste to an appropriate disposal point and provides sufficient vacuum to enable pumping of dense consolidated sludge.

When connected the vacuum pump is capable of exhausting at 1,700 litres per minute. The pump can be reversed to pressurise the tank to assist the discharge into a transfer tank. The engine is mounted on a hinged plate with a rod linkage to apply tension to the belt drive. The vehicle is fitted with a motorcycle throttle and a braking system. A turntable draw bar is used for towing. The unit is equipped with 4 metres of 75mm diameter PVC hose connected to the tank with aluminum quick release couplings (Alabaster & Coffey, 1996).

Micro-enterprise for pit latrine exhaustion

The Vacu-tug was established in 1996 as a micro-enterprise with Kenya Water for Health Organization (KWAHO), operating in Kibera, the largest informal settlement in Nairobi, Kenya, with an estimated population of 750,000 in an area of 225 hectares (Wesley,1998). This was done as a joint effort together with the Nairobi City Council through the primary health care unit of the Public Health Department because their consent was required for the disposal of the sludge to municipal sewer. (Alabaster & Coffey,1996)

Only two trunk sewer lines provide sanitation in this area of Nairobi and there are no house connections to the sewer line. The main methods of excreta disposal are simple, unimproved pit latrines and a limited number of VIP latrines. It is estimated that more than one hundred people share a latrine. As a result, the "wrap and throw" method, known locally as the "flying toilet", is reported to be commonly used and is a danger to the drinking water supply.

Access to adequate latrines is a general problem in Kibera because the area is very densely populated and there is limited space to build new latrines as and when the old ones fill up. On-site sanitation options are becoming increasingly unsustainable and continued densification will increase pressure on existing latrines as evidenced by the growing predominance of the "wrap and throw".

Other than manually digging out the contents of the latrine which poses a health risk, the Vacu-tug is the only way to empty them and so has the monopoly in Kibera. When a pit latrine is almost full, the potential customer goes to the Vacu-tug office to request the services of the Vacu-tug. The customer pays in advance (the charge for removing 500 litres of waste from the pit latrines is 400 Ksh.) and leaves with an approximate idea of the time and day on which the pit latrine will be emptied. The Vacu-tug operators arrive on the specified day at the latrine and empty it. The customer hands them the receipt which the operators should return to the office. In the event that the pit is not emptied, the customer is entitled to a refund or another day is scheduled for the pit latrine to be emptied.

The working week is from Monday to Friday while Saturday is reserved for any emergency cases, such as flooding due to heavy rains etc. The Vacu-tug operators have two main functions – responsibility for emptying pit latrines using the Vacu-tug and carrying out the daily maintenance of the machine and routine repair work. They should report any problems they encounter with the machine while it is in operation to the office.

The Vacutug machine has proved to be effective in emptying the latrines. Although the Vacu-tug exhauster met the technical requirements for a latrine emptying service, the single machine operating in Kibera, cannot cope with the demand of the service which currently greatly exceeds supply and has led to some of the customers being refunded as their latrines have not been serviced.

Objectives of micro-enterprise in running vacu-tug

• To provide a service that is affordable and environmentally sustainable

• To improve the sanitation situation of the area being serviced

• Decrease the pollution and contamination of groundwater resources

• To improve general aesthetics of the surrounding area

• To reduce the impact of diseases such as cholera and typhoid and diarrhoea

• To provide employment to the urban poor.

• To serve the people

• To provide a service that is accessible and easily obtained, efficient and reliable.

This document is an output from a project funded by the UK Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of the DFID.
 

For further information, please contact:
 

Dr. Graham Alabaster, HSO Infrastructure Unit UNCHS(Habitat) P.O. Box 30030 Nairobi Kenya Tel: +254 2 623054 Fax: +254 2 623588 or 624265/6/7 E-mail: graham.alabaster@unchs.org

Intermediate Technology Development Group would like to acknowledge Dr. Graham Alabaster of UNCHS (Habitat) and Manus Coffey Associates for providing the original material on the Vacu-tug.

TVE/ Practical Action gratefully acknowledge support for the HANDS ON programmes from the UK's Department for International Development (DFID), the European Commission (EC), the UN Foundation and UNDP/The Equator Initiative in collaboration with the Government of Canada, IDRC, IUCN, BrasilConnects and the Nature Conservancy.