Case Study: Horizon Power
Investigate the nature and extent of contamination at a site prior to redevelopment in rural Australia for Horizon Power
In 1998 ERM was commissioned to undertake an investigation and install a product recovery system at a diesel fired power station in Menzies, Western Australia (WA) after a spill had occurred. Menzies is a remote gold mining town in Western Australia whose population numbers between 70 and 100.
No longer in operation and owned by Horizon Power, a regional power corporation in WA, the former diesel site again come under investigation by ERM in 2007 associated with the
commencement of the Contaminated Sites Act, 2003. Horizon Power was also considering divestment options for the site.
ERM’s role focused on providing Horizon Power with a better understanding of the nature and extent of impacts and to assess risks with respect to the site’s proposed future land use. The assessment was also designed to provide sufficient information for the site to be accurately classified by the regulator under the Contaminated Sites Act, 2003.
ERM installed monitoring bores and addressed a Phase Separated Hydrocarbon (PSH) plume, implemented a sampling program to improve existing characterization of contamination and conducted a quantitative health risk assessment.
Benefits and Value
Through the targeted additional investigations and quantitative risk assessment process, ERM was able to distinguish risk associated with shallow soil and those associated with groundwater impacts, with the latter assessed as acceptable for the proposed land use. As a result, Horizon Power was assured that to make the site suitable for the proposed land use only soil impacts needed to be addressed, which represented a manageable scope of work by comparison with complex groundwater remediation.