Remediating A Wastewater Lagoon To Become An Ecological and Community Asset (#19)
FELICITY HEWETT
1
- Water Technology, Eastwood, SOUTH AUSTRALIA, Australia
- The Swamp Road sewage treatment lagoons servicing the town of Strathalbyn were constructed in 1981 and were partially superimposed over an existing, natural wetland. Swamp Road treatment lagoons ceased operations in 2018 when a new facility became operational. Alexandrina Council has a responsibility to restore the site to its pre-development state and to protect environmental values. This prompted an investigation of options, with a key focus on remediation of the treatment lagoons, restoration of the natural wetland and
- An assessment of the existing (and future) land use and potential contaminants was undertaken with a focus on:
- Understanding the ecological values of the property and the eco-hydrological history of the site.
- Undertaking a Tier 1 qualitative risk assessment.
- Understanding the hydrological behaviour of the site and how the remnant natural wetland interacts with its catchment.
- Three staged remediation strategies were developed for the decommissioning of the site. For each strategy, an estimate of earth works, concept design and associated cost-benefit analysis was formulated.
- The project has highlighted the importance of understanding the eco-hydrological history of the site to help inform rehabilitation design. Additionally, the assessment, provided the opportunity to identify potential sources of contamination (current site use) that may impact on the suitability of the site for re-development or warrant further investigations. By understanding the predevelopment hydrological conditions and the potential state of the rehabilitated wetland, new hydrological regimes have been considered to rehabilitate the contaminated land for the benefit of the environment and the community.
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