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."