CSG Water Model

The problem/issue

Coal seam gas extraction produces quantities of water from deep coal seams which typically contains between 2000 – 3000ppm of various salts, metals and carbonates.

Without treatment disposal options for the very high volumes of water are limited (and generally, incompatible with environmental responsibilities).

A typical coal seam gas operation may product up to 200ML/day of water.

PolyGenomX

Coal seam gas water is most commonly contaminated with high burdens of both Salt (NaCl2) and Sodium Bicrbonate (NaHCO3).

Specially adapted PolyGenomX  reed and tree varieties have been established to absorb significant quantities of both salts, breaking down them down into Sodium, Chlorine, Carbon (fixed as sugars within the plant), and Oxygen.

Using especially designed wetlands densely planted with halophytic reeds for the capture and conversion of sediment, suspended solids, heavy metals and other contaminants, and their uptake by these specially bred plants has been well researched and proven effective, efficient and sustainable.

However, while reeds provide an almost immediate solution to salt uptake and water usage, and while they are capable of yielding a harvest of salt-rich, high protein cattle fodder, their absorption capacity by area is as nothing compared  to the performance capabilities of specially adapted polygenomic trees.

These trees have the ability to accumulate salts in the hard tissue areas, and dispose of it permanently. When the timber is harvested and eventually rots or is burned, its sodium is readily oxidised and presents no on-going problems.

A Wetlands Model

In this model, wetlands are used as the initial desalination and water uptake medium until such time as the forest component has gained sufficient biomass to take over those roles.

The wetlands consist of a series of biological filters, ponds and floodplains which then lead to an irrigated plantation forestry area.

Each wetland area of approximately 26Ha is projected to use 5.5-6.5ML/day and capture and convert 5,000 – 5,800tonnes of salts per year at year 5.

The wetlands take two years to establish fully at which point their water consumption is expected to increase with age to year 10. A series of biological filters (biofilms) contain aggregate to support halophytic plants, and to attract salt ions from the coal seam gas water.

Plants in all zones of the wetland accumulate salts and can be harvested for a range of applications including animal fodder and fertiliser.

The wetlands support new ecosystems and biodiversity on site and integrate with surrounding ecosystems and environment.  Species selection can include local plants which can be subjected to PolyGenomX and reintroduced to the site for long term/permanent site remediation.

Costings

Four wetland systems as described are likely to cost in the vicinity of $10m over two years.  This includes an allowance for formative earthworks estimated at $0.5m/system) and site-specific species development and primary research costs of approximately $1.5m.

At Year 5, four such wetlands would be utilising 26.4ML/day of coal seam gas water.

The ongoing maintenance costs of such a system have been estimated at $200,000 per annum per system which is not only very cost effective compared to alternative methods of water treatment and utilisation, and salt and brine disposal, but can be expected to be offset by a range of incomes including carbon credits, fodder sales and timber and/or biomass  royalties.

Bottom Line

PolyGenomX technology in the form of specifically-bred plants and trees, and intelligent land and water use, can provide a natural, sustainable bioremediation system that meets all of the challenges generated by coal seam gas water, while delivering a sustainable and community-acceptable solution.

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