Contaminated Site Projects
BACKGROUND
EnviroScience Solutions was commissioned to restore a parcel of land, and monitor for any residual impact to the waterway, that had been contaminated by a 20,000-litre caustic soda tank near the Wallerawang Sewage Treatment Plant in the Central West of NSW.
Mark of EnviroScience said, “the site was a former landfill and is currently being developed as a major access route by Transport for NSW. The works involved were highly specialised and demonstrate EnviroScience’s skills and capability.”
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SOLUTION
EnviroScience Solutions worked with the client to undertake a comprehensive investigation of the site, with approximately 12,000 litres of caustic soda migrating from the tank bund along an unnamed, largely dry, watercourse.
Remediation options were then appraised, with a remediation action plan drawn up to undertake the remedial works and validation reporting to restore the parcel of land. Daily monitoring of the creek also took place throughout the project.
The remediation works comprised the excavation and off-site removal of impacted soils and vegetation to an appropriately licenced landfill. The lateral and vertical extent of the excavation was then determined by the collection of soil samples every five metres along the length of the watercourse and field testing for pH, on both sides and at the base of the excavation. The waste soil (1,379 tonnes, approximately 800 m3) was classified by EnviroScience and removed offsite to an appropriately licenced landfill. The remediation excavation was backfilled with virgin excavated natural material taken from stockpiled quarried material.
CONCLUSION
The pH field screening and the validation laboratory results demonstrated that the remediation excavation has been conducted successfully. Water monitoring of the nearby Pipers Flat Creek also indicated there had been no off-site impact.
This was reported to the NSW EPA, with the project and subsequent reporting reviewed, and in part, authored by EnviroScience Solutions’ Certificated Environmental Practitioner: Site Contamination Specialist.
