Following soil and groundwater investigations in 2006-2009 (PDF 331.3KB), Orica proposed to remediate areas of the Former ChlorAlkali Plant (FCAP). A soil washing process was proposed to be used. Following successful on-site pilot-scale trials, a soil washing process was brought to the site from Canada. The Soil Washing Project ran from April to August 2011, but was unable to meet Orica’s remediation objectives.
In January 2012 the NSW Environment Protection Authority (EPA) issued a Management Order to Orica which required Orica to (among other things):
- prepare a remedial options appraisal report (including an assessment of additional technologies listed by the EPA);
- nominate an independent expert, approved by the EPA, to peer review the above report;
- identify a preferred remedial approach; and
- prepare a Remediation Action Plan.
A Remediation Options Appraisal Report (ROAR) was submitted to the EPA on 16 April 2012.
Following an extensive evaluation of the four technology options, it was concluded in the report that the preferred option is on-site containment. This would comprise an impervious cut-off wall being installed around all four sides of the principal mercury source area (installed all the way down to the bedrock), capped with a vapour and liquid-tight concrete slab.
The concrete slab would be used to relocate the existing salt stockpile, which is near the Denison Street boundary of the BIP.
The ROAR was peer reviewed by an independent expert approved by the EPA, Kendrick Jaglal, of AECOM, based in the USA.
In April 2012 Orica also submitted two Remediation Action Plans (RAPs) for the project to the EPA for approval:
- RAP for Block G (for the main contamination area) – proposed to install a concrete cap and barrier walls down to bedrock to safely contain the mercury contamination in soil; and where practical, collect and safely store liquid mercury.
- RAP for Blocks A and M – proposed to excavate smaller isolated areas of mercury contaminated soil to the extent practicable; excavated contaminated soil proposed to be treated and disposed of off-site at a licensed facility and/or placed beneath the Block G cap.
In August 2013 the EPA issued a Management Order setting out the framework, action and timeframes for the remediation work, and added conditions to the Environment Protection Licence to allow the remediation work to proceed.
See Site Audit Statements prepared by the EPA-accredited Site Auditor for this Project.