A kit designed to treat household waste water for reuse could be one of the ways to tackle water scarcity in rural areas of the Middle East and North Africa, according to a Canadian organisation.
“This is a household-based technology mainly for rural areas to treat grey water that comes from the kitchen sink and bath for re-use,” said Hammou Laamrani, project coordinator at the Regional Water Demand Initiative of the International Development Research Centre (IDRC), based in Canada.
“It is a very simple, easy to manipulate, inexpensive water treatment kit which can be handled without special training and technological skills, and can be used in the context of poor and marginalised communities,” Laamrani told IRIN in Istanbul at the World Water Forum.
Grey water, also called `sullage’, is non-industrial wastewater generated from domestic processes such as dish washing, laundry and bathing. Greywater comprises 50-80 percent of residential wastewater - everything from the home, except blackwater, or sewage.
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The kit consists of two large PVC barrels about 1.2m high, each able to contain up to 200 litres of water, pipes and sand. Before reaching the barrels, the waste water goes through a separate filter where things like small bits of food are removed. The barrels are filled with sand; there is an anaerobic digestion of the organic matter when the water goes through the sand filter and becomes cleaner.
“The quality of the treated water is improved chemically and biologically; it [the filter] removes the pathogens, particularly the E. coli that could pose a health risk. It also removes parasite eggs as they cannot go through the filter because the filter is a kind of a bio-membrane that removes all those things,” Laamrani explained.
It has a socio-economic impact, it has a positive impact on the environment and it’s viable in terms of technology used,” Laamrani said.
Waste water treated by sand filter has very little nitrogen and potassium, and in terms of chemical pollution poses no risk for the soil, according to Laamrani. It is not a risk to soil because it does not have mineral components that can increase soil salinity and degradation, and it is not a risk to human beings in terms of exposure to pathogens, he said.
“It reduces the amount of water that goes into cesspits - sanitation in rural areas. So they don’t need to clean the cesspit so often - only once every three months, instead of once a week. This reduces the cost of emptying the cesspits,” he said.
|Promoting the use of an outdoor sink in Rachaya Casa, Lebanon to maximise greywater use|
“This water can also be used for productive purposes. It is used for the irrigation of saplings, particularly olive trees like we saw in Jordan… This water can also be reused in the household, like for flushing toilets,” he said.
However, it is not suitable for crops or vegetables consumed without cooking, like cucumbers and tomatoes, he said.
“The cost of the kit is $300-400, and in some cases even less depending on the price of components in any given market. If you take into account the productive use of the treated waste water and the reduced frequency of cesspit evacuation, outlay costs can be recouped in a year in places like Jordan and Lebanon,” the IDRC official said, adding that they also had projects in the occupied Palestinian territories and Yemen.
Maintenance is simple: sand in the barrels needs to be changed every 10-15 years, Laamrani said.
One of the drawbacks with the system initially was the smell: “There was no technology to remove the smell when the water was in the barrels. But it has been overcome with a new system that takes the gas out of the barrels… No longer is there a risk of attracting ants or other insects,” he said.
“We expect governments and development agencies to be engaged at this stage, but this is not yet happening,” he said, adding that there was a need for an effort to make such solutions popular. “A social marketing exercise is needed to promote it, but we cannot do that ourselves because our role is to see whether this works, and when it works we will tell people.”
Laamrani said that there was no single solution to the water problem in North Africa and the Middle East but that all options should be kept open.
|Promoting backyard irrigation using grey water in Rachaya Casa, Lebanon|
Some researchers say scaling up household water treatment is premature, and that more research is needed before it can be recommended to policy-makers.
Wolf-Peter Schmidt and Sandy Cairncross from the London School of Hygiene and Tropical Medicine said in a report published by the Environmental Science and Technology journal that the household water treatment (HWT) had been advocated as a means to substantially decrease the global burden of diarrhoea and to contribute to the Millennium Development Goals.
"To determine whether HWT should be scaled up now, we reviewed the evidence on acceptability, scalability, adverse effects, and nonhealth benefits as the main criteria to establish how much evidence is needed before scaling up. We found that the acceptability and scalability of HWT is still unclear, and that there are substantial barriers making it difficult to identify populations that would benefit most from a potential effect," the authors said.
"The nonhealth benefits of HWT are negligible. We conclude that widespread promotion of HWT is premature given the available evidence. Further acceptability studies and large blinded trials or trials with an objective health outcome are needed before HWT can be recommended to policy-makers and implementers," they added.