Cabot Institute blog

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Monday, 14 March 2016

The Nikki Project: Designing a rainwater harvesting system for an African health centre

Last summer three Engineers Without Borders (EWB) members conducted a six week recce on water supply in Nikki, Benin, last summer. After building contacts with local engineers, schools and hospitals, sourcing handwritten archived data, and finding many interesting answers to our questions, we are now working hard on designs for a rainwater harvesting system and planning this summer’s work. This blog is about our project, why it’s important and how we’re going about it.
Main high street in Nikki, northern Benin.
The Nikki Project aims to address water supply problems in the small district of Nikki, Benin. A big layer of granite near to the ground surface means there is only a seasonal water table. This means the Benin government’s method of borehole water supply, which works for the rest of the country, does not work here. Citizens are given a few hours of water supply per day (at the best of times). This water is cut until 2 am and rarely lasts past 5 am; certainly not ideal for schools and hospitals that need water for treatment during the day. Instead, citizens turn to private boreholes, wells and at the worst times, an untreated lake outside the city.
Map showing Benin at the bottom of the image.
Engineers Without Borders Bristol are partnered with a Spanish charity, OAN International, who identified this problem two years ago and asked EWB Bristol to help tackle Nikki’s water supply issues. Last summer our aim was to build a partnership with a local service, who we trusted to maintain the system in our absence and who we thought would be a good working partner to trial our designs.

Back in the UK about 25 of us meet every week to work on this project. Our main task this year has been the design of a rainwater harvesting system for a small health clinic. This clinic was established by two male nurses, funded from the money they earned working for the Benin national health service. They run the clinic by working 12 hours shifts each, with dedication and fantastic vision. Like all health services in Benin the centre charges for their services, but unlike the hospitals makes no profit from the sale of medicines. The hygiene measures taken were extraordinary for Benin; to paraphrase a Spanish medic volunteer, this was 'the first time [he] has seen a Benin child being told to wash their hands’. The clinic deals, amongst other things, with malaria and pregnancy: the two biggest causes of death in the area.
The health clinic that EWB are working with to provide a rainharvesting water supply.
The EWB Bristol team surveying the health centre site in Benin.
Our rainwater harvesting solution will consist of a large 90,000 litre storage tank, a water treatment system, and a small water tower to gravity feed the water into existing taps in the clinic. The tank will collect water during the rainy season and store it safely until the dry period when no water is available from the government supply.

This type of system has become very successful and widespread elsewhere in Sub-Saharan Africa, and if successful this type of system could be expanded to suit more clinics or schools in the region. We chose to work with this health centre because of the nurses’ incredible dedication to their cause; before we had finished explaining the concept, they had already started discussing how they would start saving up for it. While contributing to the materials is certainly something we are discussing as the cost of materials and labour is not high in Benin, a sense of ownership is key to the system being maintained properly and thus being a success.
An example of pipes not properly attached and fallen down in the wind leading to an abandoned RWH tank. This tank was built 2005. The current staff have no recollection of it ever functioning.
We are still exploring design options for our rainwater harvesting system:
  • Should the pump be manual or electric (practical in everyday or with a higher risk/cost of replacement)?
  • Should the water be chlorinated in the tank or after the tank or both? Is it worth the money if it will be chlorinated again anyway?
  • Would someone prefer a monthly job or a daily job in maintaining the water treatment system? If we use a Bernoulli chlorinator will it make chemical concentrations easier or more difficult to control? Possibly easier if they understand and potentially disastrous if they do not?
  • What construction materials are best? This needs to be considered with respect to practicality, local skill availability, durability and what is culturally accepted.
We are affiliated by Engineers Without Borders UK who are there for advice, provide pre-departure training for volunteers and offer insurance while out there. We have gratefully received £2,000 from the university Alumni Foundation and £11,000 from the Queen’s School of Engineering to support the project and the lab testing we’re planning before the trip this summer. We will be blogging and updating our website as the project progresses.

For more information about this project, photos, travel reports and journal entries can be found on our website: beninwater.my-free.website.

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This blog is written by Daniela Rossade, a 2nd year mechanical engineering student at the University of Bristol and is running this project as part of Engineers Without Borders Bristol.
Daniela Rossade

EWB Bristol is always looking for advice and people who have experience with rainwater harvesting and international development to learn from. We also value feedback on our ideas. If you are interested your help would be gratefully appreciated.  Please contact Daniela at ds14678@my.bristol.ac.uk.


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