Coal seam gas water
To produce coal seam gas (CSG), wells are drilled into underground coal seams, bringing water (CSG water) from the seams to the surface. This process reduces pressure in the seams which allows CSG to be released. The quality of CSG water quality varies greatly, however it is generally rich in salts and other minerals.
The amount of CSG water produced over the life of a project is known as the ’water production profile’. This profile is linked to: the volume of water in the coal seams; the permeability of the coal seam; and, the rate and volume of gas production. The largest volumes of CSG water are primarily recovered in the early stages of CSG production, decreasing exponentially over time.
The volume of CSG water produced at each well and across a CSG project will change over time. Because of this, the management of CSG water is likely to require a number of approaches or solutions working together.
These management solutions may vary through the life of the operation, and will often differ between geographical areas. This is because of the differing geological characteristics of the coal seams, the proximity of the extraction site to available beneficial uses, the qualities and characteristics of the surrounding environment, and the quality of the CSG water.
It is important that CSG operators are strategic and proactive in their management of CSG water so that impacts on the environment are avoided and managed, and to ensure the water is used in a way that reflects its value as a resource. Wherever possible, CSG water should be used and managed in a way that is of benefit to the community, and reduces impacts on the environment.
- CSG Water Management Policy
- Approving the beneficial use of CSG water
- CSG water BUA approval requirements
- CSG Water Irrigation
- Other CSG Water Uses
- Approving the disposal of CSG water
- Salt and brine
- Regulated structures including dams
- Evaporation dams
The role of the Coal Seam Gas Water Management Policy 2012—ESR/2016/2381 (formerly EM738) is to:
- clearly state the government’s position on the management and use of CSG water
- guide CSG operators in managing CSG water under their environmental authority (EA)
- ensure community understanding about the government’s preferred approach to managing CSG water.
The objective of the policy is to encourage the beneficial use of CSG water in a way that protects the environment and maximises its productive use as a valuable resource.
The objective of the policy is to be achieved by managing CSG water in accordance with the following two priorities:
Priority 1—CSG water is used for a purpose that is beneficial to one or more of the following: the environment, existing or new water users, and existing or new water-dependent industries.
Priority 2—After feasible beneficial use options have been considered, treating and disposing of CSG water in a way that firstly avoids, and then minimises and mitigates impacts on environmental values.
Consistent with a commitment in the policy, the Environmental Protection Regulation 2008 (EP Regulation) was amended so that better quality CSG water is exempt from the definition of regulated waste. This change applies where groundwater has:
- a pH between 6 -10.5; and
- an electrical conductivity of less than 15,000 μS/cm.
This amendment means that additional tracking, transport and disposal requirements only apply to strongly saline CSG water, and brine concentrates. Importantly, this results in a reduction in regulatory burden for the majority of CSG water.
Untreated CSG water that does not meet the water quality standards or treated CSG water that is not of a suitable quality, will remain a regulated waste.
CSG operators must hold an EA under the Environmental Protection Act 1994 (EP Act) before any work can take place on tenure. An EA applies to the tenure holder and is for the tenure on which the activity is being carried out.
As part of an EA application under the EP Act, CSG operators must demonstrate how their water will be managed in accordance with the policy. CSG operators are also required to submit an annual evaluation of how effective and appropriate management of CSG water has been. This annual evaluation is carried out in consideration of the measurable criteria. Read more about measurable criteria for the management of CSG water.
Under the EP Act, waste is defined as including anything that is left over, or an unwanted by-product, from an industrial, commercial, or domestic activity. There are a range of regulatory requirements that are placed on the management of waste.
As CSG water is a left over and unwanted by-product, it is initially regarded as a waste. However, under the Waste Reduction and Recycling Act 2011 (Waste Act) a waste can be approved for use as a resource if it is considered to have a beneficial use other than disposal. If a waste is approved as a resource, it is no longer considered a waste for the purposes of the EP Act. This means there is no need for assessment or consideration around how the waste is to be managed under the EA.
Under a beneficial use approval (BUA), the resource can be provided to third parties, and has no restrictions on whether the CSG water can be used on or off-tenure. This is because a BUA is not restricted in application to the holder of the CSG operator or to the tenure on which the activity is being carried out.
Where a general BUA is in place for the proposed use of the water, the CSG operator has no application or assessment requirements, and can simply operate in accordance with the conditions in the general BUA.
This approval path is the preferred option for complying with the objective of the policy.
There are two types of approvals of a resource for beneficial use—general and specific. A general BUA has clear standards which, if complied with, do not require individual assessment by the department. Anyone can operate under this type of BUA provided they comply with the conditions of the BUA.
A specific BUA requires an individual assessment and only applies following approval by the department. Applications for a specific BUA will be assessed in accordance with chapter 8 of the Waste Act.
The department has developed the following general BUAs for CSG water:
- General Beneficial Use Approval—Irrigation of Associated Water (including coal seam gas water)
- General Beneficial Use Approval—Associated Water (including coal seam gas water)
The department has detailed the standards expected for the irrigation of CSG water in General Beneficial Use Approval – Irrigation of Associated Water (including coal seam gas water). These standards are designed to ensure that irrigation of CSG water carries no greater risk than what is acceptable for any other irrigation scheme.
There are two approval paths for this option: standard water quality conditions, and variation to standard water quality conditions. If the standard water quality conditions cannot be met, an independent suitably qualified person (SQP) can be used to certify that varied water quality criteria can be used.
To assist an independent SQP in fulfilling their obligations under the General Beneficial Use Approval – Irrigation of Associated Water (including coal seam gas water), a quick guide has been developed. The quick guide provides a checklist of considerations to ensure that the SQP has appropriately considered the proposed irrigation scheme providing certification to the department.
A Statement of Reasons for each condition in the General Beneficial Use Approval – Irrigation of Associated Water (including coal seam gas water) explains why conditions were determined to be necessary.
In the General Beneficial Use Approval—Associated Water (including coal seam gas water), the department has detailed the standards expected for a range of other beneficial uses of CSG water. These uses include: aquaculture, coal washing, dust suppression, construction activities, landscaping and revegetation, research and development, stock and domestic activities. These standards are designed to ensure that CSG water is appropriately conditioned for the purpose authorised.
A Statement of Reasons for each condition in the General Beneficial Use Approval—Associated Water (including coal seam gas water) explains why conditions were determined to be necessary.
An EA may authorise the use of CSG water. However, the CSG water remains a waste and requires consideration and assessment against the standard criteria and regulatory requirements in the EP Act, and EP Regulation.
As an EA applies to the holder of the tenure on which an activity is being carried out, it cannot approve the use of CSG water off-tenure or to a third party unless the department is satisfied that the water poses no environmental risks and is fit for all purposes when leaving the tenure or being supplied to a third party.
This is because the act of supplying CSG water off-tenure or to a third party is a waste disposal activity under the EA. As the CSG operator is responsible for meeting EA conditions, these conditions cannot apply off tenure or restrict or apply to a third-party. Therefore the CSG water must meet a high-quality standard, be fit for any purpose and pose no environmental risks in order to be authorised under the EA as waste disposal.
If a CSG operator wishes to use CSG water on tenure, the EA cannot approve this disposal of waste unless the department is satisfied that any potential environmental risks identified are appropriately avoided, minimised and mitigated. This will require the CSG operator to submit an application (along with a corresponding application fee) for the department to assess in accordance with waste management considerations under the EP Act. In this circumstance, a strict conditioning framework including water quality standards, operational standards and disposal methods will be applied to the EA.
While waste disposal of CSG water in this context may provide a benefit to existing or new users both on or off-tenure, it is not the preferred approval path for the beneficial use of CSG water.
Importantly however, to streamline the assessment process under an EA, the two existing general BUAs for associated water (which includes CSG water) included consideration of the relevant standard criteria and regulatory requirements in the EP Act and EP Regulation respectively. Accordingly, a CSG operator who wishes to use CSG water on tenure may streamline the process by complying with conditions that are consistent with those in the general BUAs.
Permit and Licence Management
Ph: 1300 130 372 (Option 4)
Fax: (07) 3330 5875
The treatment of CSG water using desalination technologies results in brine and, ultimately, salt residues that must be appropriately managed. The concentration and composition of salts depends on the characteristics of the CSG water and the treatment process.
The salinity of CSG water is typically measured as the concentration of total dissolved solids (TDS) with values ranging from 200 to more than 10,000 milligrams per litre.
By comparison, good quality drinking water has TDS value of less than 500 milligrams per litre. The TDS of sea water is between 36,000 and 38,000 milligrams per litre. Brine is defined as saline water with a total dissolved solid concentration greater than 40,000 milligrams per litre.
The Coal Seam Gas Water Management Policy 2012—ESR/2016/2381 (formerly EM738) requires that saline waste is managed in accordance with the following two priorities:
Priority 1—Brine or salt residues are treated to create useable products wherever feasible.
Priority 2—After assessing the feasibility of treating the brine or solid salt residues to create useable and saleable products, disposing of the brine and salt residues in accordance with strict standards that protect the environment.
The requirements for assessing the potential hazards of dams or levees (referred to as regulated structures) associated with planned CSG activities are outlined in the manual and guideline below:
- Manual for assessing consequence categories and hydraulic performance of structures—ESR/2016/1933 (formerly EM635)
- Structures which are dams or levees constructed as part of environmentally relevant activities—ESR/2016/1934 (formerly EM634)
CSG companies applying for an EA must demonstrate via certification from a Registered Professional Engineer of Queensland that the design and construction of their regulated structure meets the hazard assessment requirements.
The guideline also contains a range of ‘model’ conditions that provides performance requirements set by the department including the requirement for CSG operators to maintain a regulated dam register. Obtain a template for the regulated dam register—ESR/2016/2506.
This risk management approach requires the resource industry to actively manage regulated structures throughout their life.
In all but exceptional circumstances, evaporation dams have been banned for CSG water, and existing dams will be either converted to other uses or decommissioned.
Once a dam is no longer being used for CSG operations it must be rehabilitated or modified for a different use (like a farm dam, if the landholder agrees).
Decommissioning and rehabilitation standards require contaminated water and underlying soil to be appropriately remediated.
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