A Clear Solution for Dirty Water Turning water into wine may be among the most
venerable of miracles, but for Greg Allgood, the
real miracle has been turning dirty water into
drinkable water. He once wowed an audience in a
Malawi village, where hundreds of inhabitants along
with the country’s Minister of Health watched
him transform a sample of the only local source
of drinking water. “There were gasps of excitement
when the water turned from this horrible, muddy
dark color to crystal clear and safe,” he
recalls.
Allgood was demonstrating PUR™,
a modest-looking packet of powder that quickly
turns turbid, health-threatening water into the
kind of liquid most of us would pay to drink out
of a bottle. PUR was developed in the late 1990s
by household products giant Procter & Gamble
(P&G) and shares its name—but not its
technology—with home tap water filters sold
by that company in developed nations. Now PUR occupies
a place at the forefront of P&G’s Children’s
Safe Drinking Water Program, a philanthropic initiative
that Allgood directs.
Allgood spends about a third of his time in places
like Malawi where people have limited or no access
to treated, potable water sources. Worldwide, as
many as 2 billion people drink water extracted
from shallow wells or polluted lakes and rivers,
with nothing like the municipal treatment systems
that are taken for granted
in most of North America and Europe. In the few
developing locales where such infrastructure might
exist—and indeed, even in the richest nations
on the planet—this resource can be ruined
suddenly by a natural disaster like a hurricane,
earthquake, or tsunami, creating an immediate,
desperate, and widespread need for safe drinking
water.
The Stuff of Life
Water can be the key to keeping death and disease
at bay. Hydration is fundamental to bodily functions,
including the ability to retain nutrients. Infants,
the elderly, and immunocompromised persons are
especially vulnerable to dehydration caused by
diarrhea, which is in turn spawned by bacteria
or viruses acquired from tainted drinking water.
In African countries ravaged by HIV/AIDS, large
portions of the adult population could likewise
succumb to even limited numbers of parasites found
in relatively clean water. “While [a healthy
person] might take a couple of weeks to get over Giardia,
it could be fatal to a person that has a reduced
immune system,” says Allgood. As opposed
to dealing with these ailments once they appear,
purifying water can keep them from appearing at
all.
The CDC became interested in point-of-use treatment
when cholera exploded in Peru in 1991 and spread
rapidly throughout Latin America. A dependence
on questionable drinking water lay at the heart
of this epidemic, and the Pan American Health Organization
estimated that it would take some $200 billion
and more than a decade to install the necessary
municipal infrastructure to alleviate the problem
throughout the region. The CDC sought alternatives
to help affected populations in the meantime.
![PUR](image/inn1.jpg) |
image: Procter & Gamble |
Chlorine bleach was among the most widely available
disinfectants, although people had difficulty gauging
how much was needed to treat a given amount of
water without creating an unpleasant taste or harmful
concentrations. The agency therefore supported
development of special bottles of dilute bleach—the
bottle caps were designed to hold just the right
amount of solution to safely treat one jerry can
of water.
These efforts caught the attention of P&G,
the leading manufacturer of bleach in many of the
affected countries. But while this approach continues
to be used in many parts of the world, it does
not remove suspended material from the water, leaving
users with water that is microbe-free but can still
look dirty. So in the mid-1990s, P&G struck
a formal Cooperative Research and Development Agreement
with the CDC, focusing on how drinking water could
be even better treated at the point of use.
Floccing Toward Solutions
P&G researchers tackled the challenge with
flocculants, agents that promote molecular aggregation
and can cause colloids or loose particles in a
liquid to amass in clumps that sink to the bottom.
Combined with large-particle calcium hypochlorite—essentially,
powdered bleach—the result was PUR, a proprietary
formulation that Allgood describes as reverse-engineering
the municipal water treatment process.
Using PUR is like making a batch of powdered
soft drink mix. Each packet of powder is designed
to treat 10 liters of water. One simply tears open
the packet, pours the powder directly into the
water, and stirs. Within a matter of seconds, any
floating material will start to flocculate into
clumps that sink to the bottom. In no more than
five minutes, all of the water is clear, and after
standing for about 20 minutes, it will be completely
disinfected. If desired, the solid remnants can
be removed with the most basic of filters, such
as a simple piece of cloth.
“The large particle size makes [the powder]
slowly dissolve, so in essence it acts like a time-released
formula of chlorine disinfectant,” Allgood
says. “That’s important, because this
product is meant to treat a huge range of waters,
from clear to extremely contaminated. ”
Even seasoned observers, including the scientists
who initially refined and tested PUR, agree that
its action is nothing less than dramatic.
“It was extremely impressive, and the most
impressive thing about it was its simplicity,” notes
John Perry, a microbiologist at Freeman Hospital
in Newcastle upon Tyne, United Kingdom. He and
his colleagues spent two years working closely
with P&G, putting PUR through its paces in
the laboratory.
“We would take a bucket of clean water
and contaminate it with all sorts of things—lots
of different types of bacteria, but also viruses,
protozoan cysts, and they’d also put a lot
of soil in it to mimic the kind of conditions that
you get in the field,” Perry says. “We
did a very detailed analysis of what came out at
the end of the process, and all of these bacteria,
viruses, and cysts had magically disappeared. ”
These results were recounted in a paper coauthored
by Perry that appeared in the June 2003 issue of
the Journal of Water and Health. Other investigators
have also published findings from applications
of PUR in various settings, ranging from ongoing
rural development activities in Kenya and Guatemala
to crises like that in Haiti following Tropical
Storm Jeanne in September 2004. Just a few months
after Jeanne struck, various aid agencies purchased
13 million packets of PUR and transported them
to parts of Sri Lanka, Indonesia, and the Maldives
when they were struck by the great tsunami of December
2004.
One Option of Many
In addition to its humanitarian value in disaster
relief, the product is also being marketed as a
household commodity in many other parts of the
world where large portions of the population lack
reliable water treatment. The pricing of such a
good varies widely from one market to another,
based on what the local market will be thought
to bear. Sally Cowal, a senior vice president with
the Washington, DC–based nonprofit firm Population
Services International (PSI), oversees the complex
dynamics of advertising and selling PUR in different
countries.
“Because we’re in social marketing,
we have a great belief that if you pay for something,
you’re much more likely to use it than if
it’s handed to you,” she says. Of PSI’s
alliance with P&G, she says, “We’re
learning a lot from one another. They don’t
know particularly well how to reach the bottom
of the pyramid in the countries we work in; that’s
what we know really well. But they know things
about brands and brand management and sophisticated
marketing and sales techniques that we [can] learn
from them. ”
Neither of these organizations present PUR as
a single, definitive answer to water treatment
under any and all circumstances. Eric Mintz, chief
of the Diarrheal Diseases Epidemiology Section
of the CDC’s Foodborne and Diarrheal Diseases
Branch, points out that dilute bleach, membrane
filters, and solar (ultraviolet) disinfection each
have their appropriate niche.
![Drinking](image/inn2.jpg) |
Learning the value
of health. Greg Allgood (left),
developer of the PUR powder, watches
as a Haitian schoolchild samples
purified water as part of a school
outreach program of P&G. The
company will invest more than $1
million over the next two years
in providing safe drinking water
in Haiti’s schools and clinics.
image: Ciesla/PSI |
“We think those all have a place, and they
all have advantages and disadvantages,” Mintz
says. “Allowing people to choose from different
options is also good.” He notes that using
PUR can be somewhat more expensive and cumbersome
than other methods. For example, although the 13¢ needed
to buy a packet of PUR in the Dominican Republic
sounds cheap, this may be much more on a per-liter
basis than a family would pay for the CDC’s
dilute bleach treatment. Plus, the PUR system requires
more components—two containers, a stirrer,
a filter—than most other systems. The optimal
option, Mintz adds, is undoubtedly the kind of
built infrastructure found in the developed world.
But Steve Luby, who heads up the CDC’s
work in Bangladesh, observes that much of the developing
world has waited four or five decades for permanent
water treatment systems to arrive. He argues that
too many lives are at risk for measures such as
PUR to be ignored.
“The numbers [of people at risk] are just
huge, and if we wait to build infrastructure we’ll
lose a generation,” he says. “We can
do something good here, and it also gets people
understanding the importance of water and the importance
of clean water, and the need to actually
invest in making water clean. We view this as a
step toward community empowerment, toward central
infrastructure solutions.”
|