Africa wide WASH technology review published

The WASHTech project has published a literature review [1] focusing on 14 technologies used in Africa in the water, sanitation and hygiene (WASH) sector.

Descriptions for each technology include a selection of interesting case studies, and an explanation as to whether the technology meets technical, financial, social and institutional success criteria.
Only two technologies met all four success criteria: hand dug wells and the India Mark II pump, and the latter only with the caveat that there was a functional maintenance system.

The least successful technology was the Playpump. Pending further research, jerry cans and the gulper were only found to meet one success criteria (technical success). Except for bio-additives to pit latrines and Playpumps, all other technologies were technically successful. The other success criteria were met by roughly half of the technologies.

Core issues that WASHTech plans to take up further include the appeal of inappropriate technologies like Playpumps and Lifestraws to naive donors, and ways to get government approval for low-cost, locally managed technologies like rope pumps, biosand filters, constructed rainwater harvesting jars, water jetting and tippy taps.

[1] Parker, A. et al., 2011. Africa wide water, sanitation and hygiene technology review. (WASHTech Deliverable 2.1). The Hague: WASHTech c/o IRC International Water and Sanitation Centre and Cranfield: Cranfield University. 93 p. : 1 box, 9 fig., 1 tab. Includes references.
Available at: 
http://wp.me/a1szDW-1o

The aim of the WASHTech project (2011-2013) is to introduce a robust Technology Assessment Framework (TAF), with local partners in Burkina Faso, Ghana and Uganda, that will assess the potential of new innovative WASH technologies. WASHTech is co-funded under the 7th Framework Programme of the European Commission’s Africa research programme. To learn more go to washtechafrica.wordpress.com

Guatemala: construction guides for rural WASH facilities

Five Cabin Latrine, Aqua Para La Salud (Guatemala). Photo: Global Water

NGO Global Water provides instructions for building rural water, sanitation, and hygiene-related facilities that were developed by its partner in Guatemala, Agua Para La Salud (Water for Health). The facilities include:

• Ferro-Cement Water Storage Tank
• Hand Washing Stations (Lavamanos)
• Complete Spring Catchment System
• Five Cabin Latrine
• Gray Water Seepage Pits

View the designs at www.globalwater.org/how-to-build.html

Constructing low-cost water tanks with ferrocement

When I say ‘water tank’, what image is conjured up in your mind? Is it one of those large black plastic tanks which you see so frequently in developing countries, usually perched on top of a small tower or on a roof? Millions of those are used around the world, so that image would be very appropriate. When I say ‘water tank’, however, I think of something else entirely. I think of ferrocement: the best, strongest, durable, cheapest, and most versatile construction material I know. And I think of the water tanks I have built myself, using it.

The term ‘ferrocement’ refers to cement reinforced with some sort of steel, be it thin wire, wire mesh or thicker reinforcement bars. Cement is great in withstanding pressure, but not very good in withstanding tension forces. For steel wire it’s exactly the reverse. A combination of the two yields an excellent construction material, which does not rust, rot or blow down in storms. Ferrocement is different from ordinary reinforced cement in that a lot more steel is used, along with a strong cement mixture. This leads to lightweight structures which can have almost any shape.

A shelter at an orphanage in Rwanda, made with ferrocement and bamboo. Photo ferrocement.com.

Boats, houses, statues
The ferrocement technique dates back to the times of Greek fresco making and the sculptural wire-and-plaster techniques of the times of Leonardo da Vinci, adapted to modern materials. Boats have been built with ferrocement, tanks (the military type), houses, statues, etc. With ferrocement, it is easy to construct earthquake resistant houses cheaply. Seeing the devastation in Haiti, it is a sad fact that this fireproof and earthquake-safe technique is so seldom used in modern construction.

Water tanks
Back to water tanks. Say, you need a 2 m² ferrocement water tank for your rainwater harvesting system. The classical technique is to start with building a cage of steel reinforcement bars, covered with chicken wire mesh. An alternative is to start with an inner form of metal sheets, which is later removed. Or, for smaller tanks, a sack filled with sand is used. Once this structure is established, a cement mixture is applied. As ferrocement is much stronger than masonry, the thickness of the walls is in the range of 10-30mm. During curing (at least 10 days, although 30 is better) the cement is kept wet and wrapped in plastic sheet. Fill’r up, and enjoy.

A ferrocement tank under construction in Guinea-Bissau. Photo: Paul Akkerman.

Your tank will be a lot cheaper than a plastic tank, have a lifetime of at least 25 years, and is easy to repair in case of cracks. The technology is extremely simple to implement, and semi-skilled construction workers can learn it with ease. Such tanks have been used on a wide scale in Asia and in some African countries, and there is huge scope for increased use for rainwater harvesting systems.

Tanks take time
Are there any disadvantages? Well, they take quite some time to build, so they are too expensive for commercial application in the western world. But this is a great advantage for small-scale enterprises in developing countries, who can employ low-cost labour. Highly motivated ferrocement entrepreneurs around the world create aqueducts, water and septic tanks, drainage systems, large flower pots for hotels and parks, shade roofs, and small houses. The more the better, I say.

Mark Westra is editor of Akvopedia.

Links:

• Other blogs in this series
• EMAS movies on (1) classical ferrocement tanks, (2) inner-form tanks , and (3) small tanks
• Wikipedia article on Ferrocement
• Making a large ferrocement tank
• Ferrocement boats
• Ferrocement.com: a bit rough, but a wealth of information
• Flying Concrete – lightweight concrete structures

Clean water – it’s right above your head

Rain falls unto roofs and then runs off. And then? You could catch it and drink it. Any suitable roof surface—tiles, metal sheets, plastics, but not grass or palm leaf—can be used to intercept the flow of rainwater and provide a household with high-quality drinking water. Rainwater harvesting systems have been used since antiquity, and examples abound in all the great civilizations throughout history.

The groundwater level may be too deep, groundwater may be contaminated with minerals and chemicals such as arsenic or salt, surface water may be contaminated with faeces or chemicals. Rainwater falls on your own roof, and is almost always of excellent quality. It enables people to manage their own water supply and provides the luxury of “water without walking”, relieving the burden of water carrying, particularly for women and children. This convenience is available at every house on which rain falls, whether on a mountain top or an island in a salt sea. It is a truly great idea.

A women using her water storage tank in Guinnee-Bissau. Photo Paul Akkerman.

Storage tanks
Once you catch the water from the roof (or other hard surfaces), you have to store it somewhere. Ferro-cement tanks, made with a layer of cement with steel-wire reinforcement, are usually the best and cheapest option, and can be made locally. When a tank is below ground, it is called a cistern. No idea why, really.

Roof rainwater is usually of good quality and does not require treatment before consumption. The most important thing to ensure water quality is a good lid, keeping out light and insects, and a filter, keeping out all kinds of dirt.

The cheapest tank of all is to use the ground beneath your feet. This is called groundwater recharge, and is simply accomplished by letting rainwater infiltrate in the ground, instead of letting it escape and flow away. When you need it, you pump it up.

As small or large as you want
A rainwater harvesting system might be a 500 cubic meter underground storage tank, serving a whole community. Or it might be just a bucket, standing underneath a roof without a gutter. Each 20 litre container of clean water might save a kilometers long walk to the nearest source of clean water, and as fetching water on cold, wet and slippery days is particularly unpleasant, even this small yield is highly valued. In Uganda and Sri Lanka, rainwater is traditionally collected from trees, using banana leaves or stems as temporary gutters.

It is a technology which is extremely flexible and adaptable to a wide variety of settings, it is used in the richest and poorest societies on the planet, and in the wettest and driest regions of the world. Let’s build more gutters!

Author: Mark Tiele Westra, Editor Akvopedia.

Links:

• Other blogs in the series “Akvo solution of the week”
• For more low-cost water and sanitation solutions, visit Akvopedia, part of akvo.org
• Indian movie by CSE (www.cseindia.org) promoting use of rainwater harvesting
• Akvopedia article on rainwater harvesting
• Wikipedia article on rainwater harvesting
• Download the book “Roofwater Harvesting: A Handbook for Practitioners” from the IRC website
• Rainwaterharvesting.org, Indian website on rainwater harvesting

Chlorination: new urban clean water system for Haitian poor gets award by former President Clinton

The first chlorination system designed for cities in poor countries is now operating in Port-au-Prince, Haiti, announced Andrew Weiss of the Washington, D.C.-based NGO International Action at the Clinton Global Initiative (CGI) meeting in New York last week. “It’s a great success,” said Weiss.

“Installed on 150 public water tanks in Haiti’s capital city, our chlorination system in supplying 400,000 residents with clean, safe water. This is the first time Haitians have had access to clean water for cooking and drinking,” commented Weiss, a board member of the group which installed the chlorinators.

Andrew Weiss received a certificate of recognition for International Action from former President Bill Clinton at the CGI meeting on September 25, 2009.

Plumbers, Joanes Bastin and Emillio Bastien, hold up a pair of chlorine tablet feeders. Photo: International Action

Weiss described the clean water system as a two-foot tube holding 20 tablets of chlorine through which water passes into a neighborhood water tank. Simple test kits allow the local operator to measure how much chlorine is dissolved and to regulate the flow.

“This is a neighborhood system,” said Andrew Weiss, “simple enough to be run by local groups and sophisticated enough to clean the water for 10,000 users. A twice-larger version of the chlorinator can make water safe for 50,000 people. We have several of the larger chlorinators operating in Port-au-Prince and more than 100 of the smaller ones.”

“International Action hopes to distribute this clean water system to cities in Asia, Africa and Latin America,” said Weiss. “Currently, no one else has a system to treat urban neighborhood water tanks in poor countries, and our system is designed for this purpose.

“The tablet chlorinators will become a major breakthrough technology in public health,” predicted Weiss. “Waterborne diseases – cholera, typhoid, hepatitis, and chronic diarrhea – are the major cause of infant and child mortality today. Our chlorine kills these disease germs in water,” he stated.

Website: www.HaitiWater.org

Video showing how the International Action chlorinator works

Source: International Action, PRNewswire / Pacific Business News, 02 Oct 2009