By Chris Rochfort, CEO, Centre for Organic Research & Education (CORE)
Per- and polyfluoroalkyl substances (PFAS/PFOS) have emerged as a major contaminant of concern due to their toxicity, resilience to breakdown and mobility in water; but a new biofiltration solution holds promise.
Widely used around the world for decades in many household, commercial and industrial products, including firefighting foam, these ‘forever chemicals’ build up in the bodies of animals and humans over time. It is reported that 98 per cent humans have traces of PFAS/PFOS in their bloodstream, with the chemicals also found in flora and fauna globally.
In late 2017, soil and water contamination from firefighting foam containing PFAS was discovered at two air force bases in Aotearoa New Zealand. As a result, all PFAS firefighting foams were banned, effective from December 2025.
In January 2024, New Zealand’s Environmental Protection Authority banned the use of PFAS in cosmetic products effective from the end of 2026 – one of the first countries in the world to take this step.
A survey of 20 locations across New Zealand in 2024 found PFAS levels ‘below the most stringent drinking water regulations in the world’, according to The University of Auckland researchers; however, the study recommended regular water monitoring to address water quality issues and ensure public safety.
The challenge now is to rapidly find effective and affordable capture and treatment solutions that can be deployed on a global scale. Many early-stage treatment systems have high capital and operating costs, and are mainly ‘centralised’ rather than being able to be deployed at the source of the contamination.
Nature-based solutions, such as biofiltration, are now being considered due to their ability to be integrated into both built and natural environments, as well as their minimal operating and maintenance costs.1
Removal of PFAS by biological methods
Amid the search for solutions, the Centre for Organic Research & Education (CORE), a Sydney-headquartered global research public charity, embarked on a bench-scale research program to determine the efficacy and efficiency of organic‑based biofiltration systems to treat PFAS/PFOS.
Commissioning the University of Newcastle to conduct independent testing and analysis, CORE used a ‘surrogate’ biofilter formulation commonly used for rain gardens and detention systems for column testing. The biofilter contained a combination that included various grades of recycled garden organics, biochar and recycled glass, all sourced from community recycling schemes.
Prior to CORE’s research with organic-based biofilters, sand filters were commonly used for managing and treating stormwater run-off; however, over time, their inability to maintain or support vegetation, and inadequate treatment performance, paved the way for organic-based filters that achieve this while having superior reactivity and surface area for treating pollutants over a longer life span.
The results demonstrated a removal rate of up to 70 per cent for PFAS/PFOS.2 While some groups of PFAS/PFOS (refer to Table 1) performed better than others, the study provided valuable intelligence for configuring future biofilter formulations to target specific or combinations of PFAS/PFOS suites.
Customising biofilter formulations to target specific PFAS/PFOS suites also provides a competitive advantage over single-product solutions.
| PFAS/PFOS Suite | Upper removal rate | Lower removal rate |
| Perfluoroalkyl sulfonic acids | 70 per cent | 9 per cent |
| Perfluoroalkyl carboxylic acids | 58 per cent | 7 per cent |
| Fluorotelomer sulfonic acids | 13 per cent | Below reportable limit. |
Table 1: PFAS/PFOS removal rates
To field-test the above bench-scale findings on PFAS/PFOS, CORE commissioned CSTS Laboratories and Eurofins Scientific to conduct testing and analysis of an existing detention basin installation containing an organic‑based biofilter media in Wallsend, near Newcastle, New South Wales.
The installation was part of a NSW Environment Protection Authority grant to CORE to expand the use of recycled organics (food and garden organics) in stormwater treatment, and involved Newcastle City Council and the University of Newcastle.
The installation was completed during March 2020 and included sampling points (see image opposite for site drainage plan/catchment aerial view) that could be accessed to sample for PFAS/PFOS efficacy.
The installation covered an area of 400 square metres, with a filter bed depth of 800 millimetres, and the biofilter was designed to a hydraulic flow rate (Ksat) of 840 millimetres per hour. The biofilter media was supplied locally by STAR Water Solutions Pty Ltd using locally sourced components.
The biofilter formulation was initially targeting heavy metals, nutrients and some toxic compounds such as carcinogenic hydrocarbons, although PFAS/PFOS were not being considered at time of installation for an urban catchment.
The sampling occurred within days of a major storm event of 22 millimetres within the catchment. The samples were collected from a combination of inlet points and the single outlet point (see Figure 1), and were analysed by Eurofins Scientific.
Four suites of PFAS/PFOS were analysed, with a total of 54 types tested – all types tested below threshold limits in the outlet samples. Testing was also conducted on a suite of heavy metals, including zinc, iron, lead, cadnium, chromium and arsenic, with all heavy metals analytes reduced to below threshold levels in the outflow samples.
Replicate testing was conducted on all tested analytes, including PFAS/PFOS. Another observation during the field testing was the exceptional plant growth around the filter bed.
In conclusion, the following benefits can be drawn from the aforementioned two research projects that can assist in protecting communities and habitats from PFAS/PFOS chemicals:
- Biofilters containing recycled materials can assist in managing/treating PFAS/PFOS.
- Organic-based biofilters can be integrated/retrofitted into built and natural environments.
- No external energy source was required for treatment.
Results from the two research projects can lead to more targeted biofilter formulation designs for PFAS/PFOS without compromising the removal of other pollutants.
STAR Water has also partnered with Indigenous-owned business Fire and Test Australasia (FTA) to combat PFAS, providing its research-backed biofiltration technology alongside FTA’s licensed Ambiolock stabilisation and surface protection technology. Effectively, FTA’s technology can mitigate the spread of contamination, helping to prevent PFAS infiltration of surfaces, while STAR Water reduces or removes PFAS levels in existing contaminations.
Ambiolock’s current testing data has recently proven a 97.8 per cent reduction of PFAS leeching on an active North Queensland hardstand site.
STAR Water believes its technology, alongside FTA’s, could play a key role in the remediation efforts, which have so far cost taxpayers in Australia in excess of A$366 million, an amount set to increase as more damage is identified.
Amid the search for solutions to the human and environmental threat posed by PFAS/PFOS, nature-based biofiltation methods clearly have enormous potential.