Coal seam gas water - dollars from dirty water ...

Australian Financial Review:

Dollars from Dirty Water

21 August 2009

Large quantities of often toxic underground water, hitherto a serious barrier to coal seam gas extraction, could become valuable in its own right with careful planning, according to water purification engineers.

Names such as Origin Energy and ConocoPhillips, Santos and Petronas, the UK's BG Group and China National Offshore Oil Corp, Arrow Energy, Shell and others are in a scramble to invest billions of dollars to extract underground methane gas from coal areas such as the Surat and Bowen Basins in Queensland or the Gunnedah Basin in NSW.

But to do this they have to extract and dispose of large amounts of often saline, sometimes quite toxic underground water.

On October 30 last year, the Queensland government barred the previous practice of simply dumping the water in large evaporation ponds, which could be the size of several football fields, It ordered coal seam gas producers to find less environmentally damaging disposal methods for the water, not to mention cleaning up the existing evaporation ponds within three years.

What is a nuisance now as toxic waste water could be converted into useable water for stock watering, irrigation, watering of forestry plantations or even town water augmentation, say water processing specialists.

The best solution would be to pipe the water to a small number of centrally located purification plants, according to water engineer Vaughan Pearce of the water planning and design division of engineers MWH. This would aggregate a steady flow of water from several individual bores over 20 to 30 years, for optimum processing of different grades of water over an economic amortisation period.

Uses could include agriculture and horticulture immediately around the processing plants, extending even to glasshouse crops.

"The blueprint should be set in the Surat Basin," Mr Pearce said. "We would have an emerging industry, be able to set the economies and refine the management."

"It would give greater certainty with environmental issues, you'd be more certain of supply and quality. The industry is on the verge of massive expansion."

On cue, Australian desalination plant proponent EES Tech has agreed to provide its thermal desalination technology to water purification group Impulse Hydro for application to coal seam gas projects, with one contract already signed. The contract provides that this plant will be available for inspection as a test site for other potential customers.

EES Tech chief executive Murray Railey said the company's JetWater thermal desalination would be added to reverse osmosis water purification systems to take the percentage of useable output water from less than 75%, from osmosis alone, up to 97 per cent from the combined application.

"This has widespread immediate application to the growing coal seam gas industry in Australia, as well as in other mines which will be required to clean their waste water before it can be discharged," he said.

EES Tech holds the rights to three environmentally sustainable technologies which could be applied in coal mining.

Impulse Hydro chief Earle Roberts said: "Because of the efficiency of the combined systems the eventual market for the units in the coal seam gas industry could exceed $50 million over the next three years."

From any individual bore, the flow of water is strongest over the first three years. Government co-ordination of individual industry projects, with waste water piped up to 50 kilometres or more to central plants, would allow varying flows from different sites to be averaged out, and lightly contaminated water segregated from toxic flows requiring more intensive processing.

One expedient to be treated with caution is simply reinjecting the water into the ground after extraction of the methane coal seam gas. In the United States, after some years of this practice, local communities are finding previously pure aquifers becoming contaminated with saline water and toxic waste products.

One possibility for the Queensland government might be to establish a centre of excellence for saline water management, MHW's Mr Pearce said.

See - AFR - Dollars from Dirty Water.