Skip navigation

Sydney Water Biosolids, Effluent and PFAS Chemicals

People may have recently read the media coverage concerning lack of testing for PFAS chemicals in drinking water throughout Australia. The media article has certainly attracted alot of interest regarding the health implications of PFAS. Visits to FoE's Australian PFAS Map have also peaked with around 15,000 visits during June. Friends of the Earth helped with alot of background into this article. What was not touched on in the reporting was the ongoing issue of PFAS contamination of waste water treatment plants including the PFAS contamination of hundreds of thousands of tonnes of biosolids produced across Australia.

Friends of the Earth Australia sent off a GIPA (Government Information Public Access) request to Sydney Water on May 8 2024 regarding detections of PFAS chemicals in drinking water, recycled water, biosolids and effluent. A response was sent back from Sydney Water on May 29 2024.

Our PFAS & Pesticide campaign relies on tax deductible donations. Any donations are greatly appreciated and go along way.

Since 2018, Sydney Water's PFAS testing has concentrated on biosolids and effluent. Almost no testing has been conducted for drinking water and none for recycled water. There has also been some soil testing at sites near waste water treatment plants.

Biosolids around Australia are frequently contaminated with PFAS. PFAS is bioaccumulative, with each application of biosolids adding to the cumulative PFAS burden. The long term problem regarding sewerage and PFAS was recently revealed at Adelaide's West Lakes Development where PFAS was detected in waterways, decades after sewerage waste was applied. 

The biosolids situation is so serious in some areas of the United States, that farmers are now taking legal action for having PFAS contaminated biosolids applied to their farmland. Will this scenario also occur sometime in the future, in Australia?

Under current biosolid scenarios where ~500,000 tonnes of biosolids are being applied to agricultural land in Australia each year, Friends of the Earth is opposed to any levels of PFAS (or other contaminants) being applied to productive agricultural land/soil in Australia.

For many years, biosolids have been sold throughout Australia, with little mention that they could be contaminated with PFAS.

Sydney Water Biosolids

Sydney Water produce about 180,000 wet tonnes of Biosolids per year.

According to Sydney Water "Around 73% of the biosolids produced from our water resource recovery facilities are directly applied to agricultural soils. Over 40 farms across the central west and south west of NSW use our biosolids to help improve soil, mainly in broad-acre farms. These large farms grow canola, wheat, oats, barley and pastures. The biosolids are spread and mixed into the soil before sowing the crops. The harvested parts of these crops don't come into direct contact with the soil-biosolids mixture. Some animals, such as sheep and cattle, may graze on crops and pastures grown in biosolids. There are withholding periods for farm animals fed on biosolids-treated pastures."

The other 27% of Sydney Water biosoids are mixed with green waste and used in agriculture, horticulture, mine rehabilitation and gardens and parklands within Sydney.

According to the Sydney Morning Herald August 15 2023: "For more than two decades, solids recovered from wastewater have been processed and transported to the Central Tablelands to nourish crop fields and pastures."

Sydney Water biosolids have also been used in pine plantations managed by the Forestry Corporation. Noone has ever publicly mentioned PFAS and microplastic pollution of these biosolids. About 1% of biosolids are now used in forestry.

According to the Colong Foundation for Wilderness (2006) : p26/27 "The radiata pine plantation in the centre of Newnes Plateau (Blue Mountains) requires tremendous inputs of nutrients and a large fire break to maintain the investment. Without huge fertilizer inputs the plantation would not be viable. To provide the needed nutrients, sewage sludge has been spread over the plantation at a rate of 30 tonnes a hectare, which causes significant pollution of the adjoining Newnes Plateau Shrub Swamps and downstream pristine environments within the World Heritage Area. The pine forest sits over an Aeolian dunefield of deep, permeable, acidic sand and is the last place to dump sewage sludge. Bushwalkers, canyoners, the local community and conservationists were successful in their campaign to have this practice stopped believing it would compromise pristine waters running off the Plateau..."

This recently logged pine plantation, 12km north east of Lithgow, in the Blue Mountains is about 2000 hectares in size. Were 60,000 tonnes of biosolids applied to this plantation? Has soil, groundwater or surface water draining from this plantation ever been tested for PFAS/forever chemicals? The plantation lies in the Hawkesbury River catchment. What other pine plantations managed by the Forestry Corporation have received PFAS contamination biosolids over the past 30 years and where are they located?

According to the Sydney Morning Herald August 15 2023: "Two 14-metre high concrete digesters have been installed at a wastewater treatment centre in Manly in a $94 million upgrade, doubling the capacity of the plant to transform sewage from one million Sydneysiders into fertiliser used to grow the state’s crops, including wheat, oats and canola.

Now Sydney Water is appealing for farms on the outskirts of the city to consider using fertiliser from human waste, called biosolids, to grow the crops that end up as products in our pantries... Six truckloads of the fertiliser head out west from North Head each week. The new digesters will boost the amount of biosolids produced per day from 40 to 70 tonnes."

Sydney Water PFAS biosolid sampling sites in 2023. The pins represent PFAS detected by Sydney Water in biosolids. The numbered pins represent the top 10 highest locations (the highest location was Richmond - although these were recorded in a holding basin at the plant) where PFAS was detected in biosolids. Where exactly are the biosolids being sent to? No mention of PFAS contamination appears to be made to buyers and users of the biosolids.

This graph shows the average level of PFAS in biosolids detected in 2023/24. It should be noted that the high levels at Richmond were from the Holding Basin at the plant. Several treatment plants where biosolids are produced were not included in monitoring in 2023. These include: Bingara Gorge, Bombo and Gerringong-Gerroa. The data also does not explain why there were zero to limited positive detections at Bingara Point, Bondi, Liverpool and North Head. What really is going on at these locations?

The 2023 data also reveals that PFAS in biosolids was dominated by the long chain PFOS.

This graph reveals that PFOS was detected in close to 100% of biosolid test regimes from Cronulla, Hornsby Heights, Malabar, Quakers Hill, Richmond Holding, Riverstone, Shellharbour, St Mary's, Wollongong, Winlamee, Walacia and Warriewood.

NEMP 3 (National Environment Management Plan)

Biosolids are discussed at length in the NEMP 3 for PFAS chemicals. The NEMP 3 have devised a complicated system where they created proposed contaminant thresholds for several relevant land uses. eg the lowest levels for biosolids are for direct contact plus milk (combined fodder and soil) to the highest being direct contact with the biosolids only.

As there are NO treatments available to remediate/remove PFASs from biosolids, it could be argued that the NEMP was produced by the Federal and State Environment ministers to continue to legally contaminate the land with PFAS. The PFAS NEMP measures will have the effect of doing long-term /permanent contamination /damage to the environment through PFAS pollution of soil, groundwater and ambient air.

They then propose three separate scenario's with a concentration of PFOS+PFHxS and PFOA that is diluted by 30 to 10 times and also a compost scenario.

According to the NEMP draft 3.0 "The ‘restricted use’ biosolids scenario in the HHERA (Human Health and Ecological Risk Assessment) assumed that biosolids are land applied and incorporated into the soil for agricultural use. The ‘unrestricted use’ biosolids scenarios assumed biosolids are applied to soil without any restrictions on the application rate."

These different scenario's are stated with the NEMP draft acknowledging p9 "dilution is not acceptable for example in soil, air, compost or other wastes or products" and p70 "Dilution of PFAS contamination is not an acceptable waste management strategy to create material suitable for reuse". NSW regulations however do not allow situations where biosolids are not mixed into the soil at a site.

Under the NEMP this apparently means that ‘where PFAS concentrations in biosolids are high enough to prohibit their beneficial re-use they must be treated or disposed of in accordance with jurisdictional requirements for PFAS contaminated wastes’. In turn this could be understood as meaning that biosolids with concentrations considered ‘high’ (between 0.0062mg/kg and 0.031mg/kg depending on the margin of safety in the restricted use category) the only options available to water authorities are landfilling or thermal treatment (gasification/pyrolysis or incineration).

MASCC refers to: Maximum Allowable Soil Contaminant Concentration.

The draft PFAS NEMP 3 maximum unrestricted use is 0.0011mg/kg (PFOS + PFHxS) and 0.005mg/kg (PFOA).

The draft PFAS NEMP 3 maximum restricted use is 0.031mg/kg (PFOS + PFHxS) and 0.13mg/kg (PFOA).

In 2023/2024 PFOS+PFHxS concentrations in biosolids detected by Sydney Water system ranged from <0.005mg/kg to 0.21mg/kg at Wallacia waste water treatment plant on November 1 2023.

In 2023/24 almost 86% of monitored treatment plants reported average PFOS+PFHxS levels above the draft NEMP unrestricted use contaminant threshold. This occurred at 19 of the 22 monitored plants.

All 340* PFOS (72.8%) and 2 (0.4%) PFOA detections were above the draft contaminant threshold for PFOS+PFHxS for unrestricted biosolid listed in the PFAS NEMP 3.0 (consultation draft). These detections in 86% of treatment plants also breached the MASCC (Maximum Allowable Soil Contaminant Concentration).

*It should be noted a 0 score was given by FoE to PFAS detections in testing which was listed in Sydney Water spreadsheets as <0.002, <0.005 and <0.01mg/kg.

In 2023/24 almost 23% of monitored treatment plants reported average PFOS+PFHxS levels above the draft NEMP restricted use contaminant threshold. This occurred at 5 of the 22 monitored plants. Quakers Hill, Riverstone, Woolongong and Wallacia. Richmond detections were above the guidelines, but were sampled from a holding basin, not biosolids.

105 PFOS (22.5%) and no PFOA concentrations were above the draft contaminant threshold for PFOS+PFHxS for restricted biosolid use biosolids listed in the PFAS NEMP 3.0 (consultation draft). Does this mean that approximately 25% of Sydney Water Biosolids (40,500 tonnes) require to be landfilled or treated thermally elsewhere?

PFAS in Sydney Water Biosolids - some examples

Over 2023/24, the fourth highest PFOS content in Sydney Water biosolids were detected at Woolongong waste water treatment plant. PFOS average levels were 31 times higher than the Proposed Unrestricted Guideline Level and averaged 97.6% of the Restricted Guideline level. The restricted guideline was breached 16 times over the time period. All samples were above the unrestricted guideline and Maximum Allowable Soil Contaminant Concentration.  Does this mean that for biosolids above 0.031mg/kg the only option is use within the treatment plant, landfill, thermal treatment?

At Wallacia wastewater treatment plant the highest PFOS levels recorded were 0.21mg/kg on 1/11/23. This is 190 times higher than the proposed unrestricted guideline and 5.8 times higher than the proposed restricted guideline. All samples were above the unrestricted guideline and Maximum Allowable Soil Contaminant Concentration. What is proposed for biosolids that breach either guideline? Who is actually checking?

Riverstone wastewater treatment plant breaches to the Restricted Guideline level mainly in the first half of 2023. All samples were above the unrestricted guideline and Maximum Allowable Soil Contaminant Concentration. Again will the bulk of biosolids from Riverstone end up in landfill? Will the bulk of biosolids from Riverstone and Quakers Hills end up being exempted by the EPA?

Sydney Water Effluent

Sydney Water effluent points from waste water treatment plants. The pins represent Total PFAS in effluent detected by Sydney Water in waste water between 2018-2022. The numbered pins represent the top 10 highest locations (the highest location was Woolongong) and other locations where PFAS was detected in waste water from 2018 to 2022. Waste water entering the ocean were dominated by the highest readings. In April the Guardian reported that one of the largest emitters of PFAS are ocean sprays. How are sewerage treatment plants contributing to this total?

The highest Total PFAS levels released into the environment by Sydney Water occurred from Woolongong treatment plant in 2019/20.

New Toxicant Default Guidelines were established by ANZECC in May 2023. These guidelines were set for freshwater only, not marine waters. The new guidelines were only for PFOS. PFOS contributed ~10% of the Total PFAS effluent entering Sydney waterways. 90% of the effluent have no ecological guidelines.

ANZECC PFOS Toxic Default Guidelines
99% 95% 90% 80%
0.0091 µg/L 0.48 µg/L 2.7 µg/L 17 µg/L

This graph highlights the highest levels of PFOS detected from Sydney Water effluent from wastewater treatment plants, released into the environment as a comparison to the 99% ecological trigger level. Of the 26 plants where PFOS testing occurred 16 (61.5%) breached the 99% freshwater trigger level between 2018-22. The highest PFOS level was detected at Richmond in 2018, at 13 times higher than the 99% ecological trigger level. None breached the 95% trigger level.

Location of water treatment plants that breached 99% freshwater default trigger level for PFOS in effluent between 2018-2022. 50% of these treatment plants will release effluent into the Hawkesbury/Nepean catchment, 37.5% of the plants will release effluent into the ocean and 12.5% into the Georges River/Botany Bay. Have any of these water treatment plants been investigated for pollution of local waterways.

For more information contact Anthony Amis [email protected]

Our PFAS & Pesticide campaign relies on tax deductible donations. Any donations are greatly appreciated

Continue Reading

Read More