MUSCAT, Oman, Jan. 11, 2012 -- The treatment of controversial hydraulic fracturing by-products in wastewater facilities has received a torrent of recent criticism, but could a reed bed process treating oil waste in the Middle East be one answer?
At the end of last week a former employee of the New York State Department of Environmental Conservation (DEC) reportedly warned that hydraulic fracturing - known as fracking - could contaminate New York’s drinking water supply.
A letter from Paul Hetzler in a US newspaper said that “hydraulic fracturing as it’s practised today will contaminate our aquifers”.
In December US environmental campaigner Robert F. Kennedy Jr. warned about treatment facilities taking radioactive contaminated wastewater from fracking processes in the Marcellus Shale region, US (see Water & Wastewater International (WWi) story).
Shortly afterwards the British Geological Survey started a project to estimate methane in groundwater levels before shale gas exploration gets fully underway in the UK, with Cuadrilla Resources already operating three sites in Lancashire.
Meanwhile in Oman, the world’s largest commercial reed bed treatment plant is being expanded for oil-polluted water at the Nimr oil field, which was previously generating 250,000 m3 of contaminated water daily.
The 235 hectare site is now treating 20% of this water with an aim to double this amount by the end of 2012. The plant layout includes a pipeline which enters the water treatment plant system and then an oil and water separator.
Water is then distributed over a polishing wetland facility, before being channelled through four wetland terraces on a gravity feed of over 2.3 million m2 area.
According to the Bauer Group – the firm behind the technology – since the project’s initiation over 53,000 barrels of oil have been recovered from the produced water stream.
Reed bed applications are not new – they can be traced back to the 1970s – but they are growing in popularity worldwide for the treatment of wastewater. With Oman's large scale site proving that oil wastewater can be processed and generate a valuable product, it raises the question of whether reed beds would be suitable to treat fracking wastewater.
Dr Roman Breuer, member of the management board, environment division, Bauer Group, told WWi: “I agree that fracking water should not be treated in common wastewater treatment plants as the water characteristic is most of the time completely different from domestic or any industrial wastewater.
“However, any wastewater can be treated. On the question of whether our application could treat fracking water, the answer is yes, but it depends. There are two main issues which on a case-to-case situation rules out the suitability of our application: high salt concentrations in the fracking water and the unpredictable flow patterns during fracking operations.
“Our applications are limited to low and medium salt concentrations and are designed to treat a constant wastewater flow over a long time period. In fracking the flow patterns are shorter and have a peak flow early in the operations, which favours mobile and modular treatment systems.”
Elsewhere, in Hungary a firm called Orgnanica has implemented inner-city wastewater treatment plants using reed bed technology (see WWi story). Using vegetation, bacterial biomass forms on plant roots, which act at a natural biofilm carrier-media.
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