Why isn’t full remediation occurring on-site?
Advances in technology and remediation methods over the last ten years enable the site to be managed in a less intrusive manner than originally anticipated.
A variety of methods have been considered for this site. The chosen methods were selected due to their effectiveness in removing contaminants, while minimising impact on the surrounding area.
Why has this taken so long?
We are currently in the final stage of clean-up on site.
Since the fire in 2001, a number of phases of investigation of soil and groundwater have been undertaken to assess the level of the contamination. Permeable Reactive Barriers (PRBs) were installed in 2010 to halt the flow of any contaminants in groundwater towards the Helena River. This final step in Q2 2018 involves treating the contamination at its source.
How do the Permeable Reactive Barriers (PRBs) work?
PRBs are a sequenced system of physical underground barriers that treat groundwater by making use of its natural flow.
As the groundwater flows through the PRBs, the chemical contaminants pass through two layers – one containing sawdust to breakdown the nitrates; and one containing zero valent iron to treat the chlorinated solvents. The treated groundwater then continues its natural flow, no longer at risk of contaminating Helena River or the surrounding environment.
Because the PRBs break down contaminants, rather than simply filtering them, the system provides a much better solution for the environment and the long term future of the site.
Are the Permeable Reactive Barriers (PRBs) working?
The site has been closely monitored over the five years since the PRBs were installed and concentrations of contaminants have been significantly reduced. No contaminants have been detected in the Helena River.
The PRB has been proven successful in breaking down the contaminants and monitoring will continue to ensure its ongoing success.
What is involved in the onsite clean-up of the former Waste Control facility?
The site of the former Waste Control facility currently has a concrete slab covering the majority of the lot. The first phase of this clean-up will involve removing this concrete and the existing services. This is scheduled to commence in Q2 2018.
Soil testing (up to a depth of two metres) will then take place and where contaminated soil is identified it will be excavated and removed to an appropriate landfill for disposal.
While this approach will be minimally invasive, dust and air quality monitoring will be in place throughout the process.
What is involved in the offsite clean-up near Stanley Street?
The ‘offsite’ groundwater contamination near Stanley Street was discovered during testing following the 2001 fire, however is believed to be unrelated to the incident.
Remediation of this area involves the injection of a mixture of emulsified vegetable oil and specifically designed bacteria that will break down the contaminants and effectively remove them from the soil.
I live/work nearby, is there any risk to my health?
This method of remediation has been specifically selected because of its minimal impact on the surrounding area.
Will there be any disruption to local businesses during this stage of work?
We aim to minimise disruption to local businesses wherever possible. If any disturbance is likely to occur, affected businesses will be notified prior to the start of works.
When will the land be ready for industrial uses?
The former Waste Control Site requires reclassification by the DWER prior to it being ready for industrial use. This is anticipated to take 12-18 months.