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Management of brine disposal into inland ecosystems

Inland disposal and/or use of brine ‘waste’ from desalination plants and groundwater pumping is a significant management issue in Australia and globally. The remote location of inland desalination or dewatering plants often limits the options for beneficial use of brine. Consequently, brine disposal into naturally saline or secondary salinised waterways is frequently considered the only economically viable means of disposal. This multi-staged project aims to evaluate brine discharge using an ecosystem services perspective, and develop and test protocols and guidelines for the management of brine in inland aquatic and terrestrial ecosystems.

This project aims to develop guidelines for the management of brine discharge into inland ecosystems, appropriate in an Australian context. The project is based on three assumptions concerning its technical basis: i) that an ecological understanding of ecosystem services is essential for human development; ii) that protocols and guidelines for discharge need to be derived from these understandings; and iii) that industry in particular, and society in general, can derive benefits from the brine, or from its appropriate management, in inland ecosystems.

Recognising the full range of ecosystem services in a context like this one requires a fundamental knowledge of the chemistry, biology, geology and hydrology of saline systems. Indeed the interaction between hydrology, nutrients, turbidity and salinity needs to be understood in order to determine the ecological regime of a wetland. Conceptual models can be produced to include identifying thresholds for ecological regime shifts for phytoplankton, benthic microbial communities and submerged vegetation (for example Sim et al. (2006a; 2006b) for saline wetlands of the Wheatbelt). The models provide a predictive capacity to managers, to determine whether ecosystem services will be degraded, maintained or enhanced as a result of development.

Using an ecosystem services approach to the management of inland aquatic ecosystems conforms with processes at the national (i.e. Commonwealth of Australia Water Act 2007) and international (i.e. Ramsar (Convention on Wetlands) 2005) levels. However, these are not yet made explicit in water quality guidelines (ANZECC 2000, currently under revision) or environmental management best practice (ISO 14000). Brine discharge in inland aquatic ecosystems is mostly covered at the state level by environmental protection regulations that deal with water quality of effluent receiving environments. Where relevant, guidelines at the state level advise that dewatering discharge to nearby wetlands, rivers, drains or drainage lines is acceptable provided that (i.e. Government of Western Australia 2000): the environmental values and beneficial uses of receiving waters are not compromised, that the receiving water quality criteria can be met, that the discharge of effluent to receiving waters is consistent with the provisions of an (applicable) ecosystem protection policy. A need exists, therefore, to make explicit links between ecosystem services (benefits), protocols for their modelling and description, and matching guidelines for development in an Australian context.

Options for disposal of brine from desalination plants in inland environments include: aquifer injection (according to aquifer conditions), reinjection (if the saline water has been extracted from the aquifer in the first place), or discharge to water treatment systems or sewage system (if appropriate), discharge to open land, reuse for agriculture or landscaping, discharge into inland surface wetlands, placement in evaporation ponds, and zero liquid disposal mechanisms. An understanding of the brine characteristics, and the consequences in the receiving environment, will enable an evaluation of these options. In remote locations, in the Australian landscape, some of these management options for brine will provide for enhanced ecosystem services (or at least maintained and not degraded).

Funding agency

National Centre of Excellence in Desalination Australia (NCEDA)

Project duration

November 2011 to November 2014


Researchers

Professor Ray Froend
Professor Pierre Horwitz
Dr Bea Sommer
The University of Western Australia, Professor Neil Coles
The University of Western Australia, Dr Vera Biermann
The University of Western Australia, Assistant Professor Carlos OCampo
The University of Western Australia, Assistant Professor Chun Woo Baek

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