Canadian Consulting Engineer

Low-tech water technologies are best in chronic emergencies, say experts

March 28, 2011
By Canadian Consulting Engineer

Americana 2011, held in Montreal on March 22-24, provided a relatively rare opportunity for francophones and anglophones involved in the environmental sectors to compare notes.

Americana 2011, held in Montreal on March 22-24, provided a relatively rare opportunity for francophones and anglophones involved in the environmental sectors to compare notes.

The environmental conference attracted 8,000 participants from 50 countries to the Palais des Congres in the downtown. Consulting engineering firms were well represented, with Golder and AMEC acting as key sponsors. Firms such as Genivar, Dillon, BPR and TetraTech also had people making presentations, taking their place along with government bureaucrats, municipal engineers, and product developers.

One session that stood out from the crowd was on March 22 about dealing with disasters. With the triple disaster in Japan under way, and other literally earth shattering events such as the Haiti earthquake and Asian tsunami still being dealt with, the question of how to provide immediate water and wastewater infrastructure to people suffering under such dire circumstances struck a chord.

The first presenter for “Water Supply and Sanitation in Natural and Manmade Disasters” was Caetano Dorea, P.Eng., a young academic from Laval University who has worked for Oxfam and spent time in Aceh after the 2009 tsunami. With just one colleague, Dorea is starting a program at Laval University to evaluate and develop water and sanitation technologies for developing countries.

Dorea started by pointing out that the “main enemy after a catastrophe, the one that results in most deaths, is diarrheal illnesses. These of course are caused by pathogens that easily transferred from fecal matter due to the dire lack of basic sanitation and clean water in the refugee camps. He showed an aerial photo of one of these camps, which showed just a mass of blue and white dots spread over the landscape. The dots were tents and tarpaulins representing homes for 150,000 people, densely packed, with no water or sanitation infrastructure to speak of.

In these scenarios most analyses show that the priority should be to deliver a larger quantity of “good” quality water, than labouring to provide a smaller stream of “excellent” quality from a high-unit, said Dorea. Units such as reverse osmosis or ozone chambers, for example, aren’t the immediate answer: “If it looks complicated, it probably is complicated, and it will be expensive,” he said.

Whether high or low tech, there are many solutions for providing clean drinking water in emergencies. However, efforts to provide technologies for clean sanitation are “lagging far behind,” said Dorea.  “We’re looking for the holy grail in terms of sanitation technology.” He pointed out that whatever the solutions, training is essential both for users and operators. In some places people have never used toilets, for example.

For supplying drinking water in disasters there are three stages of response, Correa said. In the first “survival” stage relief agencies try to provide up to 5 litres per person a day. In the second stage of the emergency they try to ramp up that number in order to provide water for washing clothes, basic hygiene and for feeding the livestock that people often bring with them to the camps.

In the third “post-emergency” stage the agencies start to reconstruct the infrastructure that was there before the disaster and also look for new sustainable supplies. Even at this rebuilding stage Dorea favours simpler systems that can be operated by non-engineers. He showed a classic photograph of a conventional concrete water treatment plant in India that stood as a ruin in the landscape. The local people were given two days of training in how to operate the plant, Dorea said, and “that was the only two days it ever operated.” Such well intentioned schemes are wasting millions of dollars, he said.

Simple “point of use” technologies that Dorea has seen work effectively in emergencies are mobile modular “batch” units. He showed an example of a corrugated circular steel tank lined in rubber. It requires simply applying a coagulant, letting it settle, then decanting water off the top into large flat “bladder” tanks where it is disinfected.

Another continuous flow solution he showed is Oxfam’s “Upflow Clarifier Kit.” This is a tank with an inverted cone inside that “works on the basis of a floc blanket clarifier.” Wrapped several times around the tank are yellow hoses to provide the water with disinfection contact time. The unit can produce 10 cubic metres of water per hour, he said. It was used in Aceh after the Indian Ocean tsunami.

Another presenter at this session was Rahul Singh, a paramedic and founder of GlobalMedic, a disaster relief agency based in Toronto. Singh has won many humanitarian awards and was listed as one of Time magazine’s most influential people in 2010.

Singh agreed with Dorea that there is no single magic bullet to providing clean water in disasters, and said they consequently use a “bag of tricks.” The cheapest and quickest solutions are disinfection tablets and sachets. Sachets are particularly effective in war zones, he said, as when handed out with a bucket and piece of cheesecloth or a tee-shirt can be used to purify 10 litres of water a day. The drawback is that the powder is toxic if eaten.

In Haiti GlobalMedic sent youngsters out on bikes carrying small mobile water treatment units. The youths went out to street corners carrying  “Trekker” units that provide 3.8  litres (1 gallon) of water per minute. This was enough for up to 1,000 people a day, Singh said. The units run off a car or motorcycle battery and include a sediment filter, a carbon filter and an ultra-violet light. They cost around $1,000.

GlobalMedic also took large treatment units to Haiti and set them up in the places where people would congregate at night for safety, such as church yards and schools. But they because of safety concerns they couldn’t operate them 24 hours, said Singh. At night marauding bands of “young angry men” who had escaped from prison during the earthquake were on the loose, armed with guns, Singh explained.

During the question and answer period, Singh echoed Dorea in saying that the simpler, cruder technologies are perhaps the most effective for now. Singh said they’re proposing simple ceramic filter units for households, for example. “The solution we’re proposing is the opposite of what we think of in terms of technologies.”


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