Qatar-based scientists are moving forward with a pilot project, which if successfully scaled-up will improve Qatar’s water security by recharging groundwater aquifers with treated waste water.
Dr Mohamed Darwish and Dr Basem Shomar of the Qatar Environment and Energy Research Institute (QEERI) have told Gulf Times that this project, which is being conducted in partnership with a delegation from Gent University in Belgium, would also improve the quality of Qatar’s groundwater by reducing salinity levels and raise the water table to make the water more accessible.
The QEERI scientists have confirmed that Qatar’s groundwater resources are currently used primarily in the agricultural sector, but salinity has increased from over extraction and sea water intrusion.
According to Dr Darwish, one third of irrigated land has been brought out of use due to increased salinity since 1990. Over use, compared to a natural rain recharge rate of less than 1% per year, has lowered the water table making extraction more difficult.
Recharging Qatar’s groundwater aquifers will also provide the country with critical water security should desalination plants be brought down due to an oil spill, for example. Qatar’s municipal water is mostly provided by desalination plants along the coastline, which provide 1.2mn cu m of water per day.
Dr Darwish told Gulf Times that given the size of the population, Qatar currently has only two days worth of groundwater stored in aquifers at normal consumption rates, which could be stretched to five days if used conservatively. According to a QEERI report on Qatar’s water issues, the country’s potable water consumption rate of 600 litres per day per capita is one of the highest in the world.
Dr Darwish explained that making waste water drinkable with advanced filtration technologies costs only a quarter of the amount spent on desalination. Desalinated water in Qatar is mostly provided by multi-stage flash systems, which have high energy needs, and the heated brackish water discharged from these plants is harmful to the environment.
According to a QEERI report, only a third of used municipal water is treated and recycled, the rest is wasted due to leakage or from buildings which have not been connected to the sewer system in the suburbs. Qatar’s current waste water recycling capacity stands at 354,000 cu m per day, and another plant with 28,700 cu m capacity has been built at the new airport site for its landscape irrigation.
Most recycled water is currently being used for irrigation and landscaping and is not directly being consumed by humans, although most of it has been sufficiently treated to be safe for drinking.
Dr Darwish said that in order to accommodate cultural sensitivities regarding the use of treated waste water, the aquifer recharge option was chosen as it provides a more sensible use for high quality water.
The plant being designed for the pilot project will produce 100,00 cu m of treated water, which will be injected 50-60m into the ground. Locations for treatment facilities and groundwater injection have yet to be determined. The filtration process will continue as the water moves through the ground and into the aquifer.
A report written by Dr Darwish explained that the recharge process through the soil will act as an “extra natural filter and can remove essentially all suspended solids, biodegradable materials, bacteria, viruses, and other microorganisms. Also, significant reductions in nitrogen, phosphorous, and heavy metal concentrations can also be achieved.”
Dr Shomar emphasised that “mother nature itself is an excellent filter for any contaminants coming from marine water, surface water, wherever.”
Dr Shomar has been involved in projects in Jordan and Palestine, where systems try to use natural filtration in treating waste water to conserve scarce resources. The system being designed and tested in Qatar has already been successfully implemented in Kuwait, and is starting to be used in the United Arab Emirates.
Dr Shomar is currently leading a complementary project that will map Qatar’s groundwater wells, and provide a comprehensive overview of the quality of the water through sample testing.
He wants to sample a minimum of 300-500 wells to create a baseline study, as part of the first ever comprehensive study of “major and minor” sources of contaminants in the country.
He also said that there was currently a shortage of published peer-reviewed data on Qatar’s water issues and resources.
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