Energy Programs, RAES Scheme, during a recent scheduled field trip to Oak Valley and its power station it was reported by the RAES team and including contractor comments on surface staining of the ground with in proximity of the power house compound. The significant staining of the ground currently represents environmental and WHS issues.
On closer investigation it was found the original design to have a significant water ingress issue, predominately due to the bunding area around the Diesel Bulk Storage Tank. Directly below the oil stain ground is the waste arrestor tank and soakage pit, the waste arrestor tank is designed to collect waste oil washed of generators and floors by the power station operator during and after servicing/maintenance. The soakage pit is connected to the waste arrestor tank and is designed for water over flow, leaving the contaminated oil in the waste arrestor tank as designed.
However, the current bunded area around the Diesel Bulk Fuel Storage Tank comprising of concrete floor and walls is connected directly to the waste arrestor. On heavy rains the water collected in the bunded area far out ways the amount of water able to be held in the waste arrestor tank and soakage pit. This is the majority cause of the heavy contamination of the ground and effectiveness of the waste arrestor tank and soakage pit due to the significant over flow.
Following the concerns of contamination to the surface, Greencap was commissioned to conduct a Limited Soil Investigation at the power station. The objective of the investigation was to assess the nature and extent of hydrocarbon contamination of soils in this area. The investigation was conducted on 11 and 12 September 2018 under the supervision of an experienced Greencap environmental field scientist
Greencap’s report recommends that when new infrastructure is installed, remedial works are carried out to remove the soils with the most significant impacts. Impacted soils should be removed from the site and disposed of at a licensed facility. It is noted that Greencap has not undertaken formal classification of the soils, but based on the current data set, they would likely be classified as high-level contaminated soils and may require treatment prior to disposal
RAES will require a project management solution to plan and execute the removal of contaminated soil and required infrastructure to ensure there is not a repeat of contamination in the Oak Valley Power Station compound, by:
Reviewing the Greencap report
Remove the contaminated soil to a place licensed in receiving hi-level contaminated soil
Replace the trade waste arrestor tank
Replace the soakage pit
Install a lean too/veranda (overhead protection from the weather elements) over the grated bunded area
Decommission existing drainage services and the Diesel Bulk Storage Tank bunded area, and
Install a new Double Bunded Diesel Bulk Storage Tank
Install a new diesel pump set and reticulation system, and
- Provide a detailed end of project report.