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

Low-cost filter: using nanotechnology to kill bacteria

Stanford University is testing an inexpensive water filter, suitable for developing countries, that removes bacteria quickly and without clogging. The filter uses a piece of cotton treated with nanomaterial inks, that kills bacteria with electrical fields but uses just 20 percent of the power required by pressure-driven filters.

The Stanford filter, which is driven by gravity, has pores large enough to allow for a high flow rate–about 100,000 liters per hour. It uses electrical pulses to inactivate bacteria by poking holes in their cell walls. The research was led by Stanford materials science and engineering professors Yi Cui and Sarah Heilshorn.

To make the filter, researchers dip a piece of cotton batting in a water-based carbon-nanotube ink, let it dry, then dip it in an alcohol-based silver-nanowire ink and let it dry again. Cui and others have used similar dipping methods to make paper-nanotube battery electrodes and nanotube textiles. The long, narrow nanotubes and nanowires get enmeshed in the fibers.

Speedy sterilization: A Stanford researcher pours water through a funnel fitted with a cotton-nanotube filter that rapidly kills bacteria. The red cords supply electricity to the device, which uses electrical fields to poke holes in the bacteria. Photo: Technology Review

In preliminary tests, described online in the journal Nano Letters, the filter inactivated about 98 percent of E. coli bacteria.

In the tests, a wire, connected to an electrical power source, which could be car batteries or solar panels, is immersed in the water filter. The researchers think that the strong local electrical fields,  which are formed at the tip of the silver nanowires, piercing the cell walls. When the electricity is off, the silver (which has antimicrobial properties) prevents bacteria from fouling the surface, a common problem with filters.

There have been no definitive studies of the effects of water-borne carbon nanotubes and silver nanowires on people and lower organisms; experiments with airborne carbon nanotubes have shown that their effect on mice lungs is similar to the effect of asbestos. But early tests on thousands of gallons of water suggest that the nanomaterials are not leaching into the water. The researchers will perform further tests to determine whether the nanomaterials remain enmeshed in the filter or are dislodged into the water over time.

The next step required is to improve the filter’s efficacy and show that it can work with a broad range of water-borne pathogens, including viruses and protozoa.

Watch the related video “Making a Nano-Water Filter for the Developing World”

Source: Katherine Bourzac, Technology Review, 08 Sep 2010

Eco-home: a model for water and sanitation self-reliance in Kathmandu

A resident of Kathmandu has adopted ecological solutions to cope with the city’s persistent water shortage and power cuts.

Report of a visit to Dr. Shrestha’s Eco-home on 14 March 2010.

Dr. Roshan Raj Shrestha in his Eco-home. Photo: C. Dietvorst

Dr. Roshan Raj Shrestha built his Eco-home in November 2002. The two and a half story building is neither connected to the city water supply nor to the sewerage network. It uses several kinds of water conservation methods including rainwater harvesting, greywater recycling, ecological sanitation, Solar Water Disinfection (SODIS) and organic waste composting. Dr. Shrestha says he was able to recover the extra investment of US$ 1,000 for his water conservations systems within three years.

The Eco-home has helped Dr. Shrestha cope with Kathmandu’s severe water crisis. The public water supply can only meet half of the actual demand and the city’s Bagmati river is turning into an open sewer. The ground water level is decreasing by 2.5 metres a year due to over extraction. The mega Melamchi Water Supply Project, started in 1998 to tackle Kathmandu’s water crisis, has been plagued by delays.

Rainwater catchment terrace and tanks. Photo: C. Dietvorst

With an average annual precipitation of 1,600 mm in the Kathmandu Valley, Dr. Shrestha found that rainwater would provide with enough water for his family of five. Rainwater is collected on two roof terraces and stored in a 9,000 litre underground tank. Excess rainwater is diverted into a dug well, which acts as an intermittent tank that can store nearly 10,000 litres and also supports shallow groundwater recharge. SODIS is used to treat rainwater for drinking water, while water from the dug well is pretreated first in a biosand filter.

Residents constructing new houses in Kathmandu now get a 10% tax rebate on their building permit fee if they include a rainwater harvesting system in their design. The rebate can reach 30% in other municipalities in Nepal, says Prakash Amatya, the Executive Director of NGO Forum.

No water goes wasted in the Eco-home. Dr. Shrestha has installed a urine diversion dry toilet in his master bedroom. Urine and composted feces are used as garden fertilizer. A small reed bed treatment system is used to recycle grey water for garden watering, washing the car and for an extra flush toilet.

Solar panel. Photo: C. Dietvorst

The latest addition to the Eco-home is a 100-Watt Solar House System (SHS), installed in 2009. The solar panels provide enough energy to light the lamps in the house. Costing US$ 1,000, the system is only affordable for middle-class families, Shrestha admits, but it has proved its worth now that power cuts of up to 12 hours a day have become standard in Kathmandu.

Dr. Shrestha is proud of his model Eco-home. He is happy to give visitors and groups of students a tour. He finds that people readily accept the concept of rainwater harvesting and greywater recycling. They are not so keen about ecological sanitation though, because of the socio-cultural barriers associated with feces.

Dr. Roshan Raj Shrestha is Chief Technical Advisor, South-Asia Region for the UN-HABITAT Water for Asian Cities Programme

Sources used:

• Eco-home for sustainable living, Himalayan Times / UrbWatSan Nepal, 19 June 2009
• Eco-home for sustainable water management : a case study in Kathmandu, Nepal. Ministry of Physical Planning and Works / UN-HABITAT. October 2008 (brochure)
• Shrestha, R.R. (2007). Sustainable water management : a case study in Kathmandu. Presentation at Ecosan – Fortaleza 2007

SODIS water bottle. Photo: C. Dietvorst

Reed Bed Treatment System for greywater recycling. Photo: C. Dietvorst

Urine diversion dry toilet. Photo: C. Dietvorst

Biosand filter. Photo: C. Dietvorst

Ceramic filters: Ugandan schools get CrystalPur kits

Uganda has been selected as the only country in Africa to pilot a project that provides cheap and pure drinking water to schools and clinics in rural Uganda. Appropriate Technology (AT) Uganda, together with Enterprise Works/ VITA, with funding from the Diageo Foundation’s Giving for Good programme, has introduced CrystalPur ceramic water filters. The filters remove bacteria and parasites from contaminated water, thus preventing water-borne-diseases.

“The gadget does not need electricity or chemicals and has no effect on the taste of water,” says Michael Oketcho, the project manager. Oketcho explains that Uganda was selected because of its high usage of open surface water.

“Most rural people use water from lakes, rivers, wells, rain water and swamps, while in urban areas, 95% of the wells and springs contain faecal matter,” says Oketcho.

The gadget filters between four and six litres of water per hour. It is suitable for schools, households, hotels, health centres, camping teams, and disaster and emergency hit areas. It weighs less than 500g and can filter up to 7,000 litres of water (350 jerrycans) before the filter is replaced. For less than the cost of one bag of charcoal, CrystalPur fllters can deliver 7,000 litres of safe drinking water.

The filter has been tested and approved by the Uganda National Bureau of Standards.

Diageo Foundation has donated 3,500 units which have been distributed in over 150 primary and secondary schools in Kampala and Wakiso districts. The water filter programme started in October 2008 and will end in October 2009.

Source: Patrick Jaramogi, New Vision, 8 Sep 2009

CrystalPur filter. Diageo/EnterpriseWorks/VIA

Desalination: IBM unveils new membane technology

Scientists at IBM Research, together with collaborators from Tokyo-based Central Glass, the King Abdul Aziz City for Science and Technology (KACST) and the University of Texas, Austin have created a new membrane that filters out salts as well as potentially harmful toxins in water such as arsenic while using less energy than other forms of water purification.

[...] Membrane filtration is currently one of the most energy efficient techniques for removing salt and improving water quality. But, conventional membranes used today are easily damaged by chlorine, which is commonly added to water to prevent bacterial growth that can cause health problems. Now, the collaborative research team has designed a new concept in membrane materials that combines resistance to chlorine damage and high performance separation behavior in mildly basic conditions, making it suitable for arsenic removal in addition to water desalination.

[...] Because of its unique chemistry, the membrane contains ionizable hydrophobes that undergo a dramatic change when they encounter mildly basic conditions – they become substantially hydrophilic. In short, the membrane, which is made with fluorine materials, transforms from a low water transporting filter to a high water transporting state in a basic environment – what the researchers call a “water superhighway.” Fortuitously, high pH also causes arsenic to become ionic resulting in a relatively easy separation by desalination membranes. Because of these conditions and reactions, when contaminated water is forced through the membrane, the arsenic is filtered out.

See also: IBM Unveils Smart Technologies, Services to Help Combat Mounting Global Water Issues, IBM, 16 Mar 2009

Web site: IBM Advanced Water Management

Source: IBM, 16 Mar 2009

Hospital water treatment: fact sheet on system for Shechen Clinic in Kathmandu, Nepal

A system for treating groundwater for the Shechen Cliinc in Kathmandu, Nepal, was constructed with a € 28,000 microgrant from the Fondation Ensemble. The system delivers water in three different qualities for different uses, as shown in the scheme below.  Read the 2-page technical sheet “Water autonomy and quality in the Katmandu Shechen Clinic” by Roger Rousse here (Fondation Ensemble, 2009).

Fondation Ensemble

Terafil water filters: clay filters promise clean drinking water in villages in Jharkand, India

Terafil technology will not only ensure clean drinking water in villages but also turn the rural people into entrepreneurs.

Chakdoha and Chapri, two villages of Ghatshila in East Singhbhum district [of Jharkand state, India], will play host to the pilot project.

The initiative has been taken by the Rural Development Trust under the Art of Living Foundation, Bengaluru. Terafil water filters have been designed by S.K. Kuntia, the head of design and rural technology department at the Institute of Mineral and Material Technology (IMMT), Bhubaneswar, a wing of the Council of Scientific and Industrial Research (CSIR), New Delhi.

[...] The terafil would cost around Rs 350 to Rs 500. The foundation has planned to rope in the corporate sector to help donate the filters as a part of their corporate social responsibility.

The filters would encourage self-employment, too. The foundation would also arrange for resources to train the villagers and help them turn into entrepreneurs.

[...] The filters are being manufactured and would be distributed across the two villages from March 31 [2009].

Source: The Telegraph, 23 Dec 2008

The Terafil water filter is especially suited for water that is rich in sediments, suspended particles, iron and certain microorganisms, i.e. for areas where water from both surface & ground water sources like dug wells, ponds, tube wells and rivers is used for drinking water.

Terafil (red clay) filtration disc. Photo: IMMT

Terafil is a burnt red clay porous media [...] produced from mixture of red clay (silt clay), river sand and wood saw dust, without using chemicals. The dough of the mixture of these materials is sintered at high temperature in a low cost coal / wood fired furnace to make the terracotta disc porous.

Domestic Terafil filter. Photo: IMMT

About 99% of turbidity, 90-95% of micro-organisms, 80-95% of soluble iron, colours etc. are effectively removed from the raw water during filtration process through the Terafil. 100% bacteria can be removed when a pinch (0.01 gm) of bleaching powder is added to a liter of filtered water. Rate of filtration is dependent upon turbidity and pressure of raw water over the Terafil.

Terafil filters are available for both domestic use and community-level use (gravity flow and on-line pressure flow models).

Read more about the Terafil filter on the IMMT web sitehere and in an IMMT leaflet.

In 2007, IMMT had already licensed the technology for making and marketing Terafil discs to four parties in Orissa and had demonstrated the technology in several other states including Uttar Pradesh and Meghalaya. Over 50,000 water filters had been distributed. The domestic Terafil filter was used extensively in Orissa in 1999 when the state was severely hit by a cyclone.

Contact: S. Khuntia, Head, Design & Rural Technology, Institute of Minerals and Materials Technology, P.O. RRL, Bhubaneswar – 751013, India.  Tel (off) : 0674 2581635-39, Fax: 0674 2581637, 2581160. Email: khuntias [at] gmail.com, skhuntia [at] immt.res.in

Source: CSIR news, Oct 2007

Kanchan Arsenic Filter: verification update

Field testing of the Kanchan Arsenic Filter (KAF), a biosand filter modified to remove arsenic from contaminated raw water, is generating encouraging results in Cambodia and Bangladesh.

The KAF was found to be highly effective in Phase 1 testing, with average arsenic removals in the 95 to 97 per cent range. All of the 10 test filters consistently reduced levels from an average of 637ppb to less than 50ppb, which is the Cambodian standard for arsenic in drinking water.

Performance of the filters was consistent over the 30-week testing span, which produced 8,400 litres of filtered water.

Phase 2 testing, now underway, involves installing the filters in more challenging locations to determine if their arsenic removal capacity can be exhausted.

The tests will also examine hardness and pH levels, water usage patterns and include a social assessment.

Related news: Arsenic removal: field testing the Kanchan Arsenic Filter in Cambodia, Source Weekly, 22 Mar 2008

See also:

• MIT TechTV video “Arsenic Poisoning and the Kanchan Arsenic Filter”  here
• Centre for Affordable Water and Sanitation Technology (CAWST): Adapting the Biosand Filter for Arsenic Removal (10 Apr 2008)

Source: CAWST Newsletter [not yet online, but should become available here], Winter 2008

Arsenic removal: four years of development and field-testing of IHE arsenic removal family filter in rural Bangladesh

Petrusevski, B. … [et al.] (2008). Four years of development and field-testing of IHE arsenic removal family filter in rural Bangladesh. Water science and  technology : vol. 58, no. 1 ; p. 53-58. doi:10.2166/wst.2008.335

Abstract

UNESCO-IHE has been developing an arsenic removal family filter with a capacity of 100 L/day based on arsenic adsorption onto iron oxide coated sand, a by-product of iron removal plants. The longer term and field conditions performance of the third generation of eleven family filters prototypes were tested in rural Bangladesh for 30 months. All filters achieved initially highly effective arsenic removal irrespective of arsenic concentration and groundwater composition. Arsenic level in filtrate reached 10 mug/l after 50 days of operation at one testing site and after 18 months of continuous operation at other 3 testing sites. Arsenic level at other 7 sites remained below the WHO guideline value till the end of study. Positive correlation was found between arsenic removal capacity of the filter and iron concentration in groundwater. In addition to arsenic, iron present in groundwater at all testing sites was also removed highly effectively. Manganese removal with IHE family filter was effective only when treating groundwater with low ammonia. A simple polishing sand filter, after IHE family filter, resulted in consistent and effective removal of manganese. IHE family filters were easy to operate and were well accepted by the local population.

Contact: Dr. Branislav Petrusevski, UNESCO-IHE Institute for Water Education, Delft, The Netherlands, b.petrusevski [at] unesco-ihe.org

Ron Rivera, Potter Devoted to Clean Water, Dies at 60

Ron Rivera / Potters without Borders

Ron Rivera liked to call his ceramic water filters “weapons of biological mass destruction.” For 25 years he traveled to poor villages throughout Latin America, Africa and Asia teaching local potters to make what appears to be a big terra-cotta flower pot but is in fact an ingenious device for purifying water. In 1998 he joined Potters for Peace and became where he became Coordinator of Filter and International Projects.

[...]

Mr. Rivera died on Sept. 3 in Managua, Nicaragua, after contracting falciparum malaria, the most dangerous form, while setting up a water-filter factory in Nigeria, said Kathy McBride, his wife. He was 60.

Read more: William Grimes, New York Times, 14 Sep 2008

Potters for Peace and Potters without Borders have set up memorial pages here and here.

See a presentation video on ceramic filters by Mr. Rivera’s below.