Making PFA contaminated land safe again at Assembly Broadmeadows

The brief

Today, Assembly Broadmeadows is a 60-hectare mixed-use commercial, industrial and retail precinct located on Sydney Road. In 2021, prior to commencing re-zoning, sub-division and redevelopment, the developer first needed to address contaminated soil.

Thanks to its former use as a car manufacturing plant, the site contained evidence of per- and polyfluoroalkyl substances (PFAS). While beneficial in manufacturing, the environmental impact and potential health risks associated with PFAS have led to increased regulation.

Our task was to excavate, relocate & stockpile contaminated soil, implement silt controls and remove impacted vegetation while also liaising with site occupants.

Execution

After soil samples were laboratory tested and results shared with the Environmental Protection Authority of Victoria, a remedial strategy was finalised. The first phase of work focussed on a small 21,000m² footprint on the property (known as Area A).

Roughly 4,000m³ of this footprint was contaminated with PFAS and needed to be excavated, stockpiled onsite (outside Area A) for further analysis to determine re-use or disposal options. Following a temporary relocation, identified stockpiles were disposed from site to a suitably licensed waste management facility. Due to variations in the concentration of contaminants, a detailed materials tracking system was implemented to ensure oversight as to the exact location of every bucket load of soil.

To prevent any movement of stockpiled soil due to rain, we deployed a range of silt controls to manage runoff and prevent sediment from entering the waterways. The stockpiles were also covered to mitigate cross contamination due to wind.

The wider Assembly Broadmeadows site was occupied by a number of short term tenancies. Coordination with these tenants was essential to address concerns and ensure positive interactions as vehicles moved through the site. A comprehensive management plan was developed to modify operating procedures – such as reduced load sizes, agreed speed limits, allocated routes and of course, containing loads appropriately. While these measures did impact site efficiency, they were important to lessen the environmental and safety concerns for the tenants.

Lastly, existing vegetation and juvenile trees located in the contaminated soil footprint (and future build location) were removed and mulched. The tree removals required assessment and collaboration with council.

Outcome

Environmental consultant testing confirmed all contamination was removed in line with EPA requirements. The site was handed back to the client ready for the development of an industrial estate. It’s a great feeling knowing our work has removed risk to human health. The project was delivered on time and on budget. We successfully ensured no cross contamination and maintained positive relations with the existing tenants. More, Industrial Environmental secured a further two projects with the same developer to perform similar remediation as additional parcels of land were released for redevelopment.