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MIT-USAID program releases evaluation of water filters

Study of water filters used in Indian homes assesses suitability, scalability, and sustainability.
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Eshita Dayani from the Indian Institute of Management-Ahmedabad and Jonars Spielberg from MIT CITE interview a local resident about his water quality and water filter usage in Ahmedabad, India.
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Caption: Eshita Dayani from the Indian Institute of Management-Ahmedabad and Jonars Spielberg from MIT CITE interview a local resident about his water quality and water filter usage in Ahmedabad, India.
Credits: Photo: Sydney Beasley

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Eshita Dayani from the Indian Institute of Management-Ahmedabad and Jonars Spielberg from MIT CITE interview a local resident about his water quality and water filter usage in Ahmedabad, India.
Eshita Dayani from the Indian Institute of Management-Ahmedabad and Jonars Spielberg from MIT CITE interview a local resident about his water quality and water filter usage in Ahmedabad, India.
Photo: Sydney Beasley

The United Nations now estimates that 90 percent of the world’s population has access to improved drinking water. But the story of access to safe drinking water is more complex, especially when it comes to the 2.7 billion people who live on less than $2 a day: In developing countries around the world, tens of millions of people rely on water filtration and purification products each year to improve their drinking water in the absence of proper infrastructure providing clean water.

Today, MIT researchers released a new report evaluating household water filters on the market in Ahmedabad, India, where these filters have become ubiquitous in households of all income levels, but aren’t properly meeting the needs of the poor.

The report, “Experimentation in Product Evaluation: Household Water Filters in Ahmedabad, India,” details the second experimental evaluation designed and implemented by the Comprehensive Initiative on Technology Evaluation (CITE), a program supported by the U.S. Agency for International Development (USAID) and led by a multidisciplinary team of faculty, staff, and students.

Launched at MIT in 2012, CITE is the first-ever program dedicated to developing methods for product evaluation in global development. CITE researchers evaluate products from three perspectives:

  • suitability, or how well a product performs its purpose;
  • scalability, or how well the product’s supply chain effectively reaches consumers; and
  • sustainability, or how well the product is used correctly, consistently, and continuously over time.

Water filters as a stopgap solution for safe water

In India, 76 million people lack access to a source of improved drinking water, putting them at risk for water-borne diseases such as diarrhea, typhoid, and cholera.

And even those with access to improved drinking water are often at risk: Water safety can be compromised by many day-to-day practices and infrastructure failings, says CITE evaluation lead Susan Murcott, a research affiliate in MIT’s Department of Urban Studies and Planning.

“We get our water 24/7. We turn on the tap and the water flows,” Murcott says. “That’s not the case in India, where households have access to piped water about five hours a day. Intermittent water supply means those households are in danger of contaminants entering the pipe when it’s turned on and off because of pressure differentials.”

Household water filters — if accessible, usable, and effective — can serve as a stopgap solution to ensure safe drinking water, especially in impoverished communities where water quality is most likely to be compromised. In Ahmedabad, where CITE conducted its research, water filters are playing this role at a significant scale. A study conducted by the government of India showed that 88 percent of people in Gujarat, the state where Ahmedabad is located, treat their own drinking water.

Opportunities for market growth and innovation

CITE studied three primary categories of water filters found in households throughout Ahmedabad — conventional particle filters, gravity non-electric filters, and reverse osmosis filters — to assess suitability, scalability, and sustainability. Ahmedabad’s water filter market is complex: CITE found more than 100 different kinds of filters on the market, and conducted nearly 400 interviews with users, retailers, manufacturers, and distributors to inform the product evaluation.

CITE found that conventional particle filters, often made from pieces of cloth or a type of mesh known as “jali,” are widely used by the poor. While these filters only cost 50 cents to $1 and are readily available, CITE’s lab tests showed all filters tested in this category to be ineffective at removing turbidity and E. coli from contaminated water.

“What was surprising is that it was so common to find the poor using these water filters,” Murcott says. “We were impressed at the awareness at all income levels of the need to treat your water. But despite their widespread use, cloth and jali mesh filters don’t work.”

According to CITE’s research, water filter products in the gravity non-electric and reverse osmosis categories are far more effective at filtering water, but most are financially out of reach for Ahmedabad’s poor. This leaves a gap in the market, where CITE’s research has identified opportunities to introduce existing solutions or to create entirely new ones.

“With the knowledge generated by this report, we can begin to think about how to address the current challenges in the water filter market,” says CITE Director Bishwapriya Sanyal, the Ford International Professor in MIT’s Department of Urban Studies and Planning. “For example, you might ask: ‘Since the poor use saris widely to filter water, could saris be  redesigned to function properly as a water filter?’ This creates the challenge of how to design a filter that’s low-cost, culturally appropriate, and also effective. Cost is central to everything. For the poor, every cent matters. To reach the poorest of the poor, this obvious fact must be taken into account in designing new technologies.”

Designing for a sustainable future

The popularity of reverse osmosis water filters among middle-income consumers has boomed in India over the past several years, as confirmed by CITE’s research in Ahmedabad. Reverse osmosis filters are more readily available to the middle class than ever before, especially with an increasing number of locally assembled, off-brand filters being sold at a lower price than branded options.

Despite the technical performance and consumer popularity of these filters, there may be cause for environmental concern: CITE’s research shows reverse osmosis filters tested in the lab waste about 70 liters of water for every 30 liters they clean.

“The negative environmental impact of household-level reverse osmosis filters was really an eye-opener for me,” Murcott says. “Larger-scale reverse osmosis systems do not produce this high of a proportion of wastewater that we see in reverse osmosis models designed for households. At the household scale, these systems waste a tremendous amount of water in a water-stressed region.”

“The CITE report comprehensively evaluates household water treatment options in Ahmedabad,” says Rob Bain, a statistics and monitoring specialist at UNICEF’s Water, Sanitation, and Hygiene program. “It clearly shows that without concerted efforts and innovation, the poorest and those in rural India will continue to drink inadequately treated water. There is promise, however, in the widespread use of cloth filters — the poor know they need to treat their water — and the local supply chains for non-branded filters which can be cheaper and just as effective.”

In the next year, the CITE program expects to publish evaluation reports on rapid diagnostic tests for malaria, post-harvest storage solutions, and water test kits, as well as conducting evaluations on solar water pumps, food aid packing, and wheelchairs.

CITE’s research is funded by USAID’s U.S. Global Development Lab. CITE is led by the Department of Urban Studies and Planning, and supported by faculty and staff from MIT’s D-Lab, Public Service Center, Sociotechnical Systems Research Center, and Center for Transportation and Logistics.

In addition to Sanyal and Murcott, co-authors on the CITE report include Daniel Frey, Jennifer Green, Jarrod Goentzel, and Jonars Spielberg. CITE conducted its research in partnership with local Indian universities including the Indian Institute of Technology, the Indian Institute of Management, TERI University, Ahmedabad University, and CEPT University.

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