Fact Sheet:  Draft Sewage Sludge Risk Assessment for PFOA and PFOS: Information for Wastewater Treatment Plants 

January 2025      Fact Sheet: Draft Sewage Sludge Risk Assessment for PFOA and PFOS: Information for Wastewater Treatment Plants

This fact sheet contains information that may be useful to operators of wastewater treatment plants (WWTPs) in addressing perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) contamination in sewage sludge.

“Are there innovative technologies available to remove and destroy PFAS in sewage sludge?

“There are several emerging PFAS destruction technologies (e.g., supercritical water oxidation, plasma gasification, pyrolysis and gasification coupled with a high-temperature thermal oxidizer) for sewage sludge. Most are still in the pilot-scale stage and further research is needed to evaluate potential products of incomplete destruction and capacity limitations. 

The EPA’s 2024 Interim Guidance on the Destruction and Disposal of PFAS and Materials Containing PFAS discusses ORD’s PFAS Innovative Treatment Team (PITT)’s research on innovative technologies, and includes a technology evaluation framework for further assessing emerging technologies. Learn more about the EPA’s ORD PITT research effort on innovative PFAS technologies.”

~~~~~~~~~~~~~~~~~~~~~~~

Application of Supercritical Water Oxidation to Effectively Destroy Per- and Polyfluoroalkyl Substances in Aqueous Matrices  https://pubs.acs.org/doi/10.1021/acsestwater.2c00548

May 15, 2023.   This publication is licensed under CC-BY-NC-ND 4.0 

Abstract - Supercritical water oxidation (SCWO) is a destruction technology to treat per- and polyfluoroalkyl substance (PFAS)-impacted groundwater, investigation-derived waste, and other aqueous matrices such as landfill leachate and aqueous film-forming foam. A SCWO system, Battelle’s PFAS Annihilator^TM, was optimized with a goal of reducing all measured PFAS to non-detect levels. Laboratory-prepared and field-collected samples with inlet PFAS concentrations up to 50 ppm were consistently destroyed to less than 70 ppt for all PFAS, when running at the determined optimal operating conditions (≥600 °C and 3500 pounds per square inch). We investigated the correlation between temperature and flowrate of the system, finding that reactor temperatures ≥450 °C destroy perfluorinated carboxylic acids, but temperatures of ≥575 °C are necessary to destroy perfluorosulfonic acids. A continuous 5-log reduction in concentration of PFAS (99.999% destruction) is demonstrated for 3 h at steady-state operation. The destruction efficiency is not impacted by the addition of co-contaminants such as petroleum hydrocarbons, and volatile organic compounds. The treated effluent is largely composed of complete combustion products including carbon dioxide, water, and the corresponding anion acids; hence, the treated liquid can be released back into the environment after neutralization.

Introduction  Per- and polyfluoroalkyl substances (PFAS) are man-made fluorinated hydrocarbons used in many applications since the 1940s due to their unique physical and chemical properties including being hydrophobic and oleophobic and having a low surface tension. (1) In addition, the presence of strong carbon-fluorine bonds provides extremely high chemical and thermal stabilities. (1,2) PFAS are widely used for commercial and industrial applications, including in aqueous film-forming foam (AFFF) for fire-training and fire-fighting operations in emergency response, manufacturing facilities for surface coatings, and mist suppressants in metal-plating operations, among others. (1) Due to their extensive applicability, PFAS have been ubiquitously detected in environmental media, human serum, and biota. (3−7) The bioaccumulation of these compounds has gained global attention due to potential health risks such as a decline in thyroid levels, decreased vaccine antibody response, and organ toxicity. (8−18) This has led to some PFAS being listed as persistent organic pollutants (POPs) under the Stockholm Convention. (19)

Considering the chronic health risks associated with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), the United States Environmental Protection Agency (U.S. EPA) established a preliminary remediation goal of 70 ng/L (or parts per trillion, ppt) in December 2019 for PFOS and PFOA in groundwater that is used as a source of drinking water. (16) In May 2022, the U.S. Environmental Protection Agency (EPA) announced the addition of five new PFAS to the list of regional screening levels (RSLs). These include PFOS, PFOA, perfluornonanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA). These PFAS are in addition to perfluorobutane sulfonic acid (PFBS), which was added to the RSLs in 2014 and updated in 2021. (20) Multiple U.S. states have recently published or are proposing PFAS levels for monitoring, notification, and/or cleanup at or below 70 ppt. (21−23)

To simplify the data presentation when the concentration of many PFAS are being reported, the PFAS are classified as PFCAs, PFSAs, and precursors/intermediates as defined in Table S1, and the raw concentration values of each measured PFAS compound are then tabulated in the Supporting Information.

Results and Discussion

Effect of Co-contaminants on PFAS Annihilation

The PFAS Annihilator has been demonstrated to greatly reduce the concentration of PFAS in laboratory-spiked samples (Figures 2, 3, 5); However, environmental samples are much more complex and can have a number of additional co-contaminants. In many of the Department of Defense (DoD) sites impacted by AFFFs due to fire-fighting or fire-training activities, it is common to find VOCs and total petroleum hydrocarbons (TPH) commingled with PFAS contamination. (64) To evaluate the practicality of applying this technology to environmental remediation, a laboratory-spiked sample was prepared consisting of PFAS, TPH (low and high concentration), and VOCs (low and high concentrations). The low-concentration spiked sample was found to contain ∼1200 ppt of total organic contaminants, and the high-concentration spiked sample was found to contain ∼7,400,000 ppt of total organic contaminants. The measurable TOC concentrations are shown in the bottom row of Figure 6, and detailed data of all analytes are provided in Table S6. The results show that the destruction of PFAS is largely unaffected by the addition of organic co-contaminants when compared to the laboratory sample that was only spiked with PFAS (Figure 6A) and that the total concentration of co-contaminants also decreases (Figure 6B,C). This proves that SCWO is effective for co-contaminant treatment along with PFAS destruction. The total PFAS concentrations and the sum of PFOA and PFOS measured in the low-concentration effluent sample (Figure 6B) and the PFAS-spiked lab sample (Figure 6A) were 15.72 and 1.23 ng/L, respectively, compared to 31.46 and 28.37 ng/L in the absence of co-contaminants. Overall, the destruction efficiency of PFCAs, PFSAs, and PFAS precursors was not affected by the presence of co-contaminants (Figure 6 and Table S6). This confirms that complexity of the feed stream does not alter the destruction efficiency of PFAS, and the results demonstrate effective destruction of co-contaminants in the PFAS-impacted IDW streams. The effluent vapor was similarly analyzed for PFAS. This analysis yielded no detectable levels of any of the 24 target PFAS, confirming that the influent compounds are being destroyed rather than escaping the system as a gas.

Figure 6

Figure 6. Measured PFCAs, PFSAs, PFAS precursors/intermediates, and co-contaminants in treatments (A) lab Sample, (B) lab sample with co-contaminants spiked at low level, (C) lab sample with co-contaminants spiked at high level, and (D) field sample. The concentrations of all PFAS compounds in the stream were less than 75 ppt after passing through the SCWO reactor.

The individually detectable co-contaminants were found to decrease to undetectable levels in both the low- and high-concentration spiked samples (Figure 6B,C), and all target organic compounds (and TOC when detected) decreased. This is an expected result as SCWO processes are not specific to breaking carbon-fluorine bonds. Carbon–carbon bonds are also expected to oxidize under the operating conditions of the PFAS Annihilator. (55)

Demonstration on an AFFF-Impacted IDW Sample

As a final proof of concept test, an AFFF-impacted IDW sample was run through the PFAS Annihilator. The field-collected sample with an initial total target PFAS concentration of 4.9 ppm was run directly through the SCWO reactor without any preprocessing, and a similar destruction efficiency of PFAS was achieved as the laboratory PFAS-spiked sample (Figure 6D). The resultant effluent total PFAS concentration was 10.2 ppt and the sum of PFOA and PFOS measured at 1.5 ppt showing six orders of magnitude reduction in PFAS (Table S6), demonstrating the PFAS Annihilator as a viable technology to destroy high concentrations of PFAS in AFFF-impacted IDW. Although there was a slight increase in the measured concentration of two VOCs from the influent to the effluent, both concentrations are below the method quantitation limit and may not be accurate. Another interesting finding was a decrease in dissolved fluoride as the field sample passed through the reactor (Table S6). This may be associated with the dramatic change in ion solubilities as water transitions from the sub to supercritical state. Methods to collect this precipitating material are underway and will allow further evaluation of this hypothesis.

In all trials (PFAS spiked, PFAS and co-contaminants spiked, and field sample), PFCA, PFSA, and PFAS precursors/intermediates show a similar level of destruction regardless of the complexity of the feed (Figure 6A–D). The total summation of measured PFAS concentration in the effluent sample of each of the laboratory and field samples was ≤75 ppt (ng/L) with no individual PFAS analyte concentration remaining higher than 70 ppt for any collected effluent sample. The influent and effluent PFAS concentrations for each of the samples presented in Figure 6 are tabulated in Table S6, which highlights the similarities in the effluent PFAS concentration that are achieved by the PFAS Annihilator from disparate inlet samples, demonstrating that the complexity of the feed stream does not alter the destruction of PFCAs, PFSAs, PFAS precursors/intermediates, or organic co-contaminants.

Although no pretreatment was required for any of the tested samples and no clogging was observed in these tests, the underlying tubular reactor may be prone to clogging from samples with high concentrations of dissolved solids. The built-in pressure and flow monitors would have deviated from their steady-state operational conditions if appreciable build up were occurring. During long-term operations, processing much larger samples for weeks at a time, the potential reactor clogging could be mitigated with the use of inline devices (e.g., a supercritical salt trap (65)) or modified reactor designs (66,67) to remove salts and other compounds that precipitate out of solution at supercritical conditions.

Identification of Byproducts:  Aqueous influent, effluent, and equipment blanks, and gaseous effluents (methanol extracts of C18 cartridges and impinger) were investigated for transformation byproducts using LC-qToF/MS analysis. Greater than 99% destruction of PFOA and PFOS was achieved in the effluent; hence, no longer chain PFAS were detected in the samples analyzed.  Some unidentified short-chain byproducts were formed (Table S7 and Figure S3) and found to elute early on the total ion chromatography (TIC) chromatogram (Figure S3). These are very low-level findings relative to the targeted compounds, which were unquantifiable without analytical standards and were not consistently seen on every run. These data suggest that SCWO completely destroyed PFAS, instead of partial mineralization, which agrees with our previous data from the liquid effluents and reactor surfaces.

Environmental Implications:

The PFAS Annihilator tested here is demonstrated as a promising technology for the destruction of PFAS and other common co-contaminants typically found at AFFF-impacted fire-training sites. This research presents optimization of the reaction conditions for the complete destruction of PFAS. The oxidant type (O₂ and H₂O₂), temperature (450–625 °C), flowrate (60–190 mL/min), and time to reach steady-state conditions were studied. The best operating conditions (≥600 °C and ≤100 mL/min or 625 °C and ≤140 mL/min) using H₂O₂ as the oxidant destroyed PFAS in laboratory-spiked solutions with initial concentrations ranging from 5 to 50 ppm to below 70 ppt levels in the resultant effluent. The optimized technology was then applied to three inlet sources (PFAS spiked with and without co-contaminants and a field sample) where it successfully reduced PFAS of different chemistries, chain lengths, and precursor presence by up to 6 orders of magnitude. These preliminary data and the impact of operational changes are valuable in upscaling SCWO systems for the destruction of PFAS in contaminated sources for environmental remediation. These data suggest that the destruction of PFAS using SCWO is independent of the oxygen source used in the reactor and that higher temperatures can be used to maintain destruction efficiency while increasing throughput.

Many technologies for the treatment of PFAS-impacted IDW rely on separation techniques, which transfer PFAS from one media to another and therefore generate PFAS-concentrated secondary waste streams (e.g., sorbents and ion exchange regenerated solvent concentrate, reverse osmosis reject, nanofiltration) that require further treatment or disposal. Incineration poses several challenges such as off-site transportation, concerns on the incomplete combustion of byproducts, high-energy requirements, immediate release of combustion products into the environment, and cost of operation. (68) As no destruction methods are readily available for the long-term effective management of PFAS-impacted IDW and these secondary waste streams, SCWO provides an effective approach. SCWO is an energy-intensive process, but much of the expended energy can be recaptured through heat exchangers in a well-designed system. SCWO is also not appropriate for thick slurries (>50% solids) as they do not pump well through a reactor. The SCWO process demonstrated here is capable of directly processing a PFAS-impacted field sample, and the effluent can be released to the environment after confirmatory analysis. Further demonstration is on-going to prove pilot- and full-scale field deployments of the PFAS Annihilator at AFFF-impacted sites, landfill leachate, as well as the destruction of stockpiled AFFF concentrates.

Supporting Information  The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsestwater.2c00548.

PFAS exposure in drinking water linked to adverse birth outcomes 

PFAS exposure linked to adverse birth outcomes

~~~~~~~~~~~~~~~~~~~~~~~~

“Guidance on PFAS Exposure, Testing, and Clinical Follow-Up. Explore insights and recommendations from the National Academies”  https://nap.nationalacademies.org/resource/26156/interactive/

POTENTIAL HEALTH EFFECTS OF PFAS

Organizations such as the International Agency for Research on Cancer (IARC), the Agency for Toxic Substances and Disease Registry (ATSDR), and the EPA have linked exposure to PFAS (particularly PFOA and PFOS) to multiple cancers, thyroid dysfunction, small changes in birthweight, and high cholesterol. Most health effects or conditions found to be associated with PFAS exposure are already common in the general population and all have multiple known risk factors. This report provides an objective and authoritative review of current evidence to determine the likely association between exposure to PFAS and elevated risk of several human health effects. The report looked at studies only of the seven PFAS being monitored in the CDC’s National Report on Human Exposure to Environmental Chemicals.

~~~~~~~~~~~~~~~~~

"Emerging environmental health risks associated with the land application of biosolids"

https://ehjournal.biomedcentral.com/articles/10.1186/s12940-023-01008-4

Environmental Health volume 22, Article number: 57 (2023) Cite this article

Over 40% of the six million dry metric tons of sewage sludge, often referred to as biosolids, produced annually in the United States is land applied. Biosolids serve as a sink for emerging pollutants which can be toxic and persist in the environment, yet their fate after land application and their impacts on human health have not been well studied. These gaps in our understanding are exacerbated by the absence of systematic monitoring programs and defined standards for human health protection.

During wastewater treatment, solids are separated from liquids and are then treated physically and chemically to produce a semisolid, nutrient-rich product known as biosolids or sewage sludge. Biosolids are typically disposed of through landfilling, incineration, or are used as a soil amendment (fertilizer) as they contain high concentrations of nitrogen, phosphorous, organic carbon, and other essential elements which are beneficial for soil quality and crop production [1,2,3]. Although the benefit of recycling nutrients necessary for crop production and avoiding the use of energy-intensive synthetic fertilizers is significant, biosolids also act as a sink for emerging pollutants [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21]. Preventing harmful exposures to these emerging pollutants when land applied remains a challenge [10, 20, 22]. The debate over safely using these human waste-derived biosolids as soil amendments is ongoing [23].

The US EPA standards for determining biosolids quality are found in Title 40 of the Code of Federal Regulations, Part 503, but are limited in focus to the presence of ten inorganic metals (As, Cd, Cu, Hg, Mo, Ni, Pb, Cr, Se, and Zn), pathogens, and vector attractiveness. These standards do not currently contain regulatory standards or thresholds that pertain to the presence of synthetic organic contaminants [10]. And, while many organic compounds degrade easily and have minimal harmful effects on the environment, other more toxic organic contaminants meet the US EPA’s definition of being persistent and can accumulate in environment, causing harm to humans and wildlife when land applied [24]. In addition to the lack of standards for monitoring persistent and toxic organic contaminants in biosolids prior to land application, there are significant gaps in our understanding of fate of these pollutants once land applied and the synergistic effects of multiple organic compounds on their distribution and transport within the environment. Moreover, the lack of efficient technologies to detect and measure these organic contaminants further reduces our ability to monitor their presence in the environment and evaluate potential impacts on human health.

The volume of biosolids produced in the US is not inconsequential. The US EPA estimates that, in states where they are the permitting authority, 4.5 million dry metric tons were produced in 2021 with nearly half (43%) being land applied [25]. The remaining biosolids were landfilled, incinerated, or managed by other methods such as storage or deep well injection. The US EPA also notes that the actual amount produced could be as much as 6 million dry metric tons according to a 2018 survey conducted by the North East Biosolids and Residuals Association, because it additionally accounts for states where US EPA is not the permitting authority. The global market for biosolids was estimated at 7.5 billion USD in 2022 and is projected to reach 10.7 billion USD by 2030 [26].

This scoping review provides a landscape of the current research regarding emerging pollutants in biosolids and their fate in the environment when land applied. Potential pathways of exposure, current detection methods, and possible impacts on human health and the environment are discussed. The need for additional research on the fate of these pollutants and their synergistic effects in the environment along with the significant need for novel treatment methods and detection technologies for emerging pollutants is highlighted. The authors call critical attention to the many knowledge gaps that currently exist to guide state and Federal regulatory frameworks for human health protection when biosolids are land applied.

~~~~~~~~~~~~~~~~~~~

Epidemiology Evidence for Health Effects of 150 per- and Polyfluoroalkyl Substances: A Systematic Evidence Map

https://ehp.niehs.nih.gov/doi/full/10.1289/EHP11185

Environmental Health Perspectives, Volume 130, Issue 9,  CID: 096003,   https://doi.org/10.1289/EHP1118

~~~~~~~~~~~~~~~~~~~~~~~~~~~

Wastewater-derived organic contaminants in fresh produce: Dietary exposure and human health concerns

https://doi.org/10.1016/j.watres.2022.118986

However, for the extreme exposure scenario, the anticonvulsant agents lamotrigine and carbamazepine, and the carbamazepine metabolite epoxide-carbamazepine exhibited the highest exposure levels of 29,100, 27,200, and 19,500 ng/person (70 kg) per day, respectively. These exposure levels exceeded the TTC of lamotrigine and the metabolite epoxide-carbamazepine, and the ADI of carbamazepine, resulting in hazard quotients of 2.8, 1.1, and 1.9, respectively. According to the extreme estimated scenario, consumption of produce irrigated with reclaimed wastewater (leafy vegetables in particular) may pose a threat to human health. Minimizing irrigation of leafy vegetables using reclaimed wastewater and/or improving the quality of the reclaimed wastewater using an advanced treatment would significantly reduce human dietary exposure to CECs.

~~~~~~~~~~~~~~~~~~~~~~

“Involuntary human exposure to carbamazepine: A cross-sectional study of correlates across the lifespan and dietary spectrum  10.1016/j.envint.2020.105951”

Though little is known about how the health of people drinking reclaimed water are affected we know that human exposure to contaminants can occur through ingestion of reclaimed wastewater-irrigated produce.  It has now been documented that individuals who consumed reclaimed wastewater-irrigated produce excreted carbamazepine and its metabolites in their urine, while subjects who consumed fresh water-irrigated produce excreted undetectable or significantly lower levels of carbamazepine. 

ABSTRACT    Treated wastewater (TWW) is increasingly used for agricultural irrigation, especially in arid and semi-arid regions. Carbamazepine is among the most frequently detected pharmaceuticals in TWW. Moreover, its uptake and accumulation have been demonstrated in crops irrigated with TWW. A previous controlled trial found that urine concentrations of carbamazepine were higher in healthy volunteers consuming TWW-irrigated produce as compared to freshwater-irrigated produce. The aim of the current study was to assess whether carbamazepine is quantifiable in urine of Israelis consuming their usual diets and whether concentrations vary according to age, personal characteristics and diet. In this cross-sectional study, we recruited 245 volunteers, including a reference group of omnivorous healthy adults aged 18–66; pregnant women; children aged 3–6 years; adults aged > 75 years; and vegetarians/vegans. Participants provided spot urine samples and reported 24-hour and “usual” dietary consumption. Urinary carbamazepine levels were compared according to group, personal characteristics, health behaviors, and reported diet. In adults, higher carbamazepine concentrations were significantly associated (p < 0.05) with self-defined vegetarianism, usual consumption of dairy products and at least five vegetables/day, and no meat or fish consumption in the past 24-hours. This study demonstrates that people living in a water-scarce region with widespread TWW irrigation, are unknowingly exposed to carbamazepine. Individuals adhering to recommended guidelines for daily fresh produce consumption may be at higher risk of exposure to TWW-derived contaminants of emerging concern.

"Longitudinal study on the multifactorial public health risks associated with sewage reclamation

."https://www.nature.com/articles/s41545-024-00365-y

 Abstract – This year-long research analyzed emerging risks in influent, effluent wastewaters and biosolids from six wastewater treatment plants in Spain’s Valencian Region. Specifically, it focused on human enteric and respiratory viruses, bacterial and viral faecal contamination indicators, extended-spectrum beta-lactamases-producing Escherichia coli, and antibiotic-resistance genes. Additionally, particles and microplastics in biosolid and wastewater samples were assessed. Human enteric viruses were prevalent in influent wastewater, with limited post-treatment reduction. Wastewater treatment effectively eliminated respiratory viruses, except for low levels of SARS-CoV-2 in effluent and biosolid samples, suggesting minimal public health risk. Antibiotic resistance genes and microplastics were persistently found in effluent and biosolids, thus indicating treatment inefficiencies and potential environmental dissemination. This multifaced research sheds light on diverse contaminants present after water reclamation, emphasizing the interconnectedness of human, animal, and environmental health in wastewater management. It underscores the need for a One Health approach to address the United Nations Sustainable Development Goals.

~~~~~~~~~~~~~~~~~~~~~~~~

"From Toilet to Tap: Risks of Direct Potable Reuse”. https://www.foodandwaterwatch.org/wp-content/uploads/2023/03/FSW_2303_ToilettoTapWaterReuse.pdf

~~~~~~~~~~~~~~~~~~~~~~~~~

“Direct potable reuse and birth defects prevalence in Texas: An augmented synthetic control method analysis of data from a population-based birth defects registry”.  March 2024. Environmental Epidemiology 8(2):e300         DOI:10.1097/EE9.0000000000000300

Abstract -   Direct potable reuse (DPR) involves adding purified wastewater that has not passed through an environmental buffer into a water distribution system. DPR may help address water shortages and is approved or is under consideration as a source of drinking water for several water-stressed population centers in the United States, however, there are no studies of health outcomes in populations who receive DPR drinking water. Our objective was to determine whether the introduction of DPR for certain public water systems in Texas was associated with changes in birth defect prevalence.

Results - There were nonstatistically significant increases in prevalence of all birth defects collectively (average treatment effect in the treated = 53.6) and congenital heart disease (average treatment effect in the treated = 287.3) since June 2013. The estimated prevalence of neural tube defects was unchanged.

~~~~~~~~~~~~~~~~~

 “Chemicals/materials of emerging concern in farmlands: sources, crop uptake and potential human health risks.  https://pubmed.ncbi.nlm.nih.gov/36444949/

The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg^-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg^-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. 

~~~~~~~~~~~~~~~~~~~~~~

 Emerging environmental health risks associated with the land application of biosolids: a scoping review”. (2023)

https://ehjournal.biomedcentral.com/articles/10.1186/s12940-023-01008-4

" Current research indicates that persistent organic compounds, or emerging pollutants, found in pharmaceuticals and personal care products, microplastics, and per- and polyfluoroalkyl substances (PFAS) have the potential to contaminate ground and surface water, and the uptake of these substances from soil amended by the land application of biosolids can result in contamination of food sources. Advanced technologies to remove these contaminants from wastewater treatment plant influent, effluent, and biosolids destined for land application along with tools to detect and quantify emerging pollutants are critical for human health protection. Vasilachi et al. further indicated that if emerging pollutants are in mixtures, the toxic effects can be cumulative and generate synergistic or antagonistic interactions, leading to the so-called “cocktail effect”, so that the difficulty of risk analysis increases."

~~~~~~~~~~~~~~~~~~

"Land Application of Treated Sewage Sludge: Community Health and Environmental Justice. Environmental Health Perspectives. " Lowman A, et al. 2013. https://doi.org/10.1289/ehp.1205470

~~~~~~~~~~~~~~~~~~

"Application of WWTP Biosolids and Resulting Perfluorinated Compound Contamination of Surface and Well Water in Decatur, Alabama, USA.” Lindstrom A., et al. 2011.    Environmental Science & Technology, 45(19):8015-21, P-1,3.

"Forever Chemicals and Risks to Farms"(2022)  https://www.dtnpf.com/agriculture/web/ag/livestock/article/2022/05/06/michigan-farm-cautionary-tale-pfas

~~~~~~~~~~~~~~~~~

"Sewage sludge in agriculture - the effects of selected chemical pollutants and emerging genetic resistance determinants on the quality of soil and crops - a review"  (2021)  https://www.sciencedirect.com/science/article/pii/S0147651321001810?via%3Dihub 

~~~~~~~~~~~~~~~~~

"Sludge in the Garden". (2021)  https://www.sierraclub.org/sludge-garden-toxic-pfas-home-fertilizers-made-sewage-sludge

~~~~~~~~~~~~~~~~~

"How microplastics are making their way into our farmland"  https://phys.org/news/2023-08-microplastics-farmland.html’

“What Goes Down the Drain May End Up On Your Plate — Your Right to Know” (2019) by Darlene Schanfald, Ph.D. https://www.sierraclub.org/sites/www.sierraclub.org/files/sce/north-olympic-group/Sewage%20Sludge%20DS%20-%20Neja%20Mag%20Sort%20Booklet%20-%2010-11-19%20new%20small.pdf

~~~~~~~~~~~~~~~~~~~

"Sewage sludge in agriculture - the effects of selected chemical pollutants and emerging genetic resistance determinants on the quality of soil and crops - a review"  (2021)  https://www.sciencedirect.com/science/article/pii/S0147651321001810?via%3Dihub '

~~~~~~~~~~~~~~~~~~~

"Role of wastewater treatment plant in environmental cycling of poly- and perfluoroalkyl substances". Hamid, H., & Li, L. (2016) Ecocycles, 2(2), 43-53

PFAS have been found in almost all biosolids tested. Harmful algae blooms have been associated with land applications of biosolids.

What to do with existing biosolids is a major question. This paper describes treatments that are being studied:

Review - "Current understanding on the transformation and fate of per- and polyfluoroalkyl substances before, during, and after thermal treatment of biosolids." https://doi.org/10.1016/j.cej.2024.152537

This review consolidates the current knowledge on PFAS transformation, destruction, and final fate before, during, and after thermal treatment of biosolids, covering lab, pilot scale, and industrial studies. It is suggested that PFAS degradation mechanisms during thermal treatment of biosolids may differ from the established pathways for pure PFAS salts, given that biosolids have a complex organic and inorganic matrix and typically have low PFAS concentrations. Among all thermal treatment techniques, pyrolysis has received extensive investigations at different scales of operation. However, for all techniques, treatment temperatures and residence time need to be sufficiently optimised for designing realistic large-scale thermal systems relevant to biosolids’ compositional peculiarities for PFAS destruction.

1.27 MB

​"Microbial and thermal treatment techniques for degradation of PFAS in biosolids: A focus on degradation mechanisms and pathways". https://doi.org/10.1016/j.jhazmat.2023.131212.   Journal of Hazardous Materials.   Volume 452, 15 June 2023, 131212.  Kumar et al

"High-temperature technology survey and comparison among incineration, pyrolysis, and gasification systems for water resource recovery facilities." Winchell, L. J., et al. (2022a). " Water Environment Research 94(4): e10715.  https://onlinelibrary.wiley.com/doi/full/10.1002/wer.10715

"Per‐ and polyfluoroalkyl substances thermal destruction at water resource recovery facilities: A state of the science review.

Per‐ and polyfluoroalkyl substances thermal destruction at water resource recovery facilities: A state of the science review - PMC (nih.gov)

Temperature is only one of the three primary parameters when assessing destruction capacity in combustion systems, the other two being residence time and turbulence. A well‐functioning SSI will submit PFAS to greater residence times and mixing (or turbulence) than the laboratory‐scale research performed to date, further promoting PFAS destruction. If PFAS parent compounds are recalcitrant or PICs are formed, they will be subjected to air pollution control equipment, which will likely capture an additional fraction of PFAS compounds. Consequently, a critical near‐term need exists to evaluate the fate of PFAS through full‐scale SSIs to understand the fate of the PFAS in the wastewater solids and identify PICs in stack emissions and air pollution control residual streams.

"Feasibility of alternative sewage sludge treatment methods from a lifecycle assessment (LCA) perspective Life Cycle Assessment of Sewage Sludge treatments." 2019.  https://www.sciencedirect.com/science/article/pii/S0959652619343653