Pure Engineering: UC Engineers Seeking Water Solutions for Poor

by Gordy Slack

Compared to developing a human/machine neural interface, say, getting a human being to Mars, or mitigating a global climate crisis, some of the twenty-first-century's most pressing engineering problems seem simple. How, for instance, to provide families living in Indian slums—or villagers in rural communities—with safe, clean sources of drinking water. Two UC projects are attempting to do just that.

 

Although the technologies employed must be straightforward, the problems themselves are anything but simple, says Ashok Gadgil, Senior Staff Scientist in the Environmental Energy Technologies Division of Lawrence Berkeley National Laboratory. Not only must the systems be safe, absolutely reliable, and very inexpensive, if they are not culturally appropriate, no one will employ them, Gadgil says. "They can end up doing more harm than good."

 

Kara Nelson, Assistant Professor of Environmental Engineering at UC Berkeley concurs. Getting clean water to families in the slums of Mumbai is "partly an engineering problem, but it is also an education problem."

 

"Most of the slum's very poor residents lack formal education and do not understand germ theory of disease transmission," says Erin Inglish. "They do not necessarily know how important it is to wash their hands carefully with soap after using the toilet and before putting their hands into the family's water source."

 

Inglish is a senior engineering student and the co-director of the Haath Mein Sehat (Health in Your Hands) Project, a student-based effort to aid Behrampada, a slum community of 175,000 people in Mumbai, on India's west coast. Since 2004, Berkeley students have been working with a group of local women from Behrampada in a two-pronged effort to reduce the transmission of water-borne diseases.

 

The first prong, the engineering component, is to design a reliable on-site filtration system that could be purchased by residents for ten dollars or less. The second aspect of the project is creating a sustainable educational system, run by local university students, that will teach the people of Behrampada hygiene and sanitation practices that will help keep their water clean.

 

Water is delivered into the slum by the Mumbai municipal water agency. There are spigots throughout the neighborhood where families draw water in large containers and carry it home. "Ironically, it is some of the cleanest water in Asia," says Inglish. "But old pipes carry it through storm drains and open sewers in the slum's narrow alleyways. By the time it gets to the spigots where the residents draw it, it is contaminated by E. coli, coliforms, and other pathogens," says Inglish.

 

Because there is only water pressure in the pipes for a few hours a day in these neighborhoods, any breaks or small holes in the pipe will let sewage and other contaminants into the system. "We know the pipes leak because when the pressure is on, we can see water spurting out of cracks and small holes. When the water pressure is low enough, it can create a vacuum in the pipes that will draw sewage right in," says Inglish.

 

Contamination also occurs when the water is put into dirty containers. It gets further contaminated by residents once it is in their homes, Inglish says.

 

Behrampada is densely developed (175,000 people live in one square kilometer) with makeshift five-story dwellings placed so close together that no vehicles can pass and no direct light can penetrate. Fixing the plumbing itself in these conditions is far beyond the reach of the of the student group, says Nelson. "For both political and engineering reasons, the plumbing situation in Mumbai is not going to change anytime soon. So the students decided early on to focus on making a point-of-use filtration system."

 

Elsewhere in India, in remote rural areas, the problems of clean water are just as pressing, but of a slightly different nature. It is here that the Ashuk Gadgil's engineering expertise is making a difference.

 

The water sources themselves are usually untreated and host various contaminants. So he has devised an inexpensive, UV-based water processing plant that can be purchased and operated affordably by villages. The garage-sized system includes a number of innovations that make it longer lasting, safer, and less expensive to buy and operate than other available UV systems, says Gadgil. The UV unit itself, which neutralizes pathogens, is suspended above the water, for instance, so that the quartz sleeve that houses it does not get fouled with algae or potassium and calcium carbonate.

 

Gadgil's system is also engineered to a 300-percent margin of safety. "It is failsafe," he says. "The system shuts down at the intake if the power goes off or there is a voltage sag or the lamp is not replaced properly. All the water already in the plant remains safe to drink," he says.

 

Providing clean water through a village-based micro-utility not only helps villagers steer clear of the pathogens in contaminated water; it also helps alleviate the health and environmental costs of boiling water in homes to purify it.

 

"There is already a fuel shortage in many rural areas and women already spend a lot of time collecting fire wood," Gadgil says. "Boiling uses three times as much fuel as cooking, and smoke from fires also causes lung cancer and cardiovascular diseases. So it is much better to purify water in other ways."

 

A private, Irvine, CA-based firm, Waterhealth International, has licensed Gadgil's design from UC, and in partnership with one of India's biggest banks, helps village councils set up affordable financing to purchase the micro-utilities. Waterhealth set up two of the garage-sized treatment centers in India in 2005; it set up fifty of them in 2006; and by the end of this year it will have totaled 200. Waterhealth is also starting programs using Gadgil's design in the Philippines and Ghana as well.

 

The Haath Mein Sehat project's treatment unit is still in prototype phase. The latest model is a two-compartment plastic unit. Water is poured into the upper section along with chlorine or some other virus- and bacteria-killing purifier. After chemical decontamination, the water passes through a filter to remove parasites as it enters the lower section where the clean water is stored until use. The lower unit is fitted with a spigot.

 

The student engineers are experimenting with different kinds of filters and materials for decontamination. Right now they are experimenting with carbon block filters with a very small pore size and halogenated resin beads that could go right into the filter units to chemically treat the water.

 

"The resin beads would not require the users to add anything extra to the water, a step that is often overlooked for financial or other reasons," says Mike Fisher, an environmental engineering graduate student and the project's technical coordinator.

 

All experimentation is undertaken with a sharp eye on cost. "Effective commercially available systems cost about 30 dollars," says Fisher. "That is about three times too much for most of the families we are working with to afford. We are trying to get the cost down below ten dollars without compromising effectiveness."

 

Gadgil, Inglish, Fisher, and Nelson agree that such real-world engineering projects can be frustrating.

 

"You have to look far beyond the engineering boundary conditions of a problem," says Gadgil. "You need a much deeper understanding of the social and human complexity of the whole situation to make it work."

 

Difficult and evasive as solutions may be, the engineers agree that the work is extremely gratifying, paying off in the ultimate reward: life.

 

"It is very satisfying to know," says Gadgil, "that more than half-a-million people are already getting safe, affordable drinking water through Waterhealth's UV systems every day."