Publicação
Unveiling microbial community dynamics during anaerobic bioremediation of pfas in the absence and presence of activated carbon
| Resumo: | Introduction: Per/polyfluoroalkyl substances (PFAS) known as 'forever chemicals,' are persistent pollutants entering ecosystems through natural and anthropogenic sources. Their extreme resistance to degradation, bioacummulation and severe health effects make them high-priority hazardous substances. Anaerobic digestion (AD) is promising for degrading recalcitrant pollutants in the presence of carbon materials (CM)[1–3]. The impact of PFAS towards anaerobic microbial groups and the role of activated carbon (AC) in mitigating PFAS effects, improving biodegradation, was investigated. Methodology: The effect of PFAS on the different trophic groups of an anaerobic granular consortia (AGC) was assessed through the specific methanogenic activity (SMA) by incubating the AGC with specific substrates: acetate, H2/CO2, and a mixture of volatile fatty acids (VFA), addressing acetoclastic, hydrogenotrophic, and acetogenic microorganisms, respectively. Increasing concentrations of perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), 0.1-100 mg/L, were tested. AC’s (0.1 g/L) effect on CH4 production was evaluated with 50 mg/L of each PFAS, and VFA. Also, a set of modified AC, to target PFAS, were tested. Results: At 0.1 mg/L PFAS, above typical levels found in wastewater systems[4], both PFAS vaguely inhibited SMA. In general, acetogens exhibited the greatest sensitivity, particularly in the presence of 80 mg/L PFOS, SMA inhibition of 30%. In contrast, the inhibition of acetoclastic methanogens was higher in the presence of 1-20 mg/L PFOA compared to PFOS. However, at 80 mg/L, PFOS exhibited a larger toxic character on the acetoclastic community (25%) than PFOA (15%). Notably, hydrogenotrophic methanogens were unaffected by either PFAS. Since PFAS had minimal impact on microorganisms, AD shows strong potential for treating PFAS-contaminated matrixes. To further evaluate this potential, the effect PFAS on CH4 production, was studied. Both PFAS inhibited the CH4 production, but the supplementation of AC reduced the SMA inhibitory by 81% for PFOA, and 78% for PFOS. Moreover, tailored AC (thermally treated under H2 atmosphere), further enhanced the detoxification, reducing the inhibitory effect of PFOA and PFOS on CH4 production rates by 95% and 85%, respectively. Conclusions: AGC were not severely affected by the tested PFAS up to 80 mg/L. However, acetogens were the most susceptible microorganisms to these compounds. The application of modified AC enhanced AD in the presence of PFAS, leading to improved methane production rates. These findings suggest that the use of tailored AC can mitigate PFAS toxicity and optimize biogas production in AD systems treating PFAS-contaminated matrices. |
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| Autores principais: | Silva, Ana Rita Pereira |
| Outros Autores: | Gomes, Jéssica; Duarte, Maria Salomé Lira; Pereira, Luciana |
| Assunto: | Anaerobic processes Specific methanogenic activity Activated carbon Toxicity |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | outro |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Introduction: Per/polyfluoroalkyl substances (PFAS) known as 'forever chemicals,' are persistent pollutants entering ecosystems through natural and anthropogenic sources. Their extreme resistance to degradation, bioacummulation and severe health effects make them high-priority hazardous substances. Anaerobic digestion (AD) is promising for degrading recalcitrant pollutants in the presence of carbon materials (CM)[1–3]. The impact of PFAS towards anaerobic microbial groups and the role of activated carbon (AC) in mitigating PFAS effects, improving biodegradation, was investigated. Methodology: The effect of PFAS on the different trophic groups of an anaerobic granular consortia (AGC) was assessed through the specific methanogenic activity (SMA) by incubating the AGC with specific substrates: acetate, H2/CO2, and a mixture of volatile fatty acids (VFA), addressing acetoclastic, hydrogenotrophic, and acetogenic microorganisms, respectively. Increasing concentrations of perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), 0.1-100 mg/L, were tested. AC’s (0.1 g/L) effect on CH4 production was evaluated with 50 mg/L of each PFAS, and VFA. Also, a set of modified AC, to target PFAS, were tested. Results: At 0.1 mg/L PFAS, above typical levels found in wastewater systems[4], both PFAS vaguely inhibited SMA. In general, acetogens exhibited the greatest sensitivity, particularly in the presence of 80 mg/L PFOS, SMA inhibition of 30%. In contrast, the inhibition of acetoclastic methanogens was higher in the presence of 1-20 mg/L PFOA compared to PFOS. However, at 80 mg/L, PFOS exhibited a larger toxic character on the acetoclastic community (25%) than PFOA (15%). Notably, hydrogenotrophic methanogens were unaffected by either PFAS. Since PFAS had minimal impact on microorganisms, AD shows strong potential for treating PFAS-contaminated matrixes. To further evaluate this potential, the effect PFAS on CH4 production, was studied. Both PFAS inhibited the CH4 production, but the supplementation of AC reduced the SMA inhibitory by 81% for PFOA, and 78% for PFOS. Moreover, tailored AC (thermally treated under H2 atmosphere), further enhanced the detoxification, reducing the inhibitory effect of PFOA and PFOS on CH4 production rates by 95% and 85%, respectively. Conclusions: AGC were not severely affected by the tested PFAS up to 80 mg/L. However, acetogens were the most susceptible microorganisms to these compounds. The application of modified AC enhanced AD in the presence of PFAS, leading to improved methane production rates. These findings suggest that the use of tailored AC can mitigate PFAS toxicity and optimize biogas production in AD systems treating PFAS-contaminated matrices. |
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