Papers

20 results
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Article Tier 2

Microplastic Degradation during Wet Air Oxidation Treatment

This review examines wet air oxidation (WAO) — a process that uses high temperatures and pressures to break down waste — as a potential method for destroying microplastics in wastewater sludge. WAO shows promising results in degrading plastic particles that survive conventional treatment, potentially preventing them from being spread on agricultural land or released into waterways. The authors outline both the advantages of the technology and the challenges that remain before it can be widely deployed. This is a useful addition to the toolkit for managing microplastics that concentrate in sewage sludge.

2025 1 citations
Article Tier 2

Efficient Depolymerization and Low-Toxicity Leaching of Polyester Microplastics through Alkali-Hydrothermal Treatment of Sewage Sludge

Researchers developed an alkali-hydrothermal treatment method that degraded 82% of PET microplastics trapped in sewage sludge, converting them into low-toxicity dissolved organic matter. The approach works by leveraging alkalinity, metal ions, and organic matter naturally present in sludge to break down plastic through hydrolysis and radical oxidation, offering a practical strategy for reducing microplastic contamination before sludge is applied to agricultural land.

2026 Environmental Science & Technology
Article Tier 2

The interaction between sludge and microplastics during thermal hydrolysis of sludge

Researchers studied how polyethylene and PET microplastics behave during thermal hydrolysis of municipal sludge at temperatures between 120 and 180 degrees Celsius. They found a mutual promotion relationship where sludge degradation accelerated microplastic aging, while the microplastics enhanced the breakdown of organic compounds in the sludge. The study suggests that thermal hydrolysis of sludge shows promise for simultaneously treating both sludge and microplastic contamination.

2024 Journal of Hazardous Materials 10 citations
Article Tier 2

Pyrolysis behavior of sewage sludge coexisted with microplastics: Kinetics, mechanism, and product characteristics

Researchers investigated the co-pyrolysis behavior of sewage sludge mixed with polyethylene and polylactic acid microplastics. They found that the presence of microplastics improved the overall pyrolysis performance and altered the composition of the resulting bio-oil and gas products. The study suggests that understanding how microplastics in sewage sludge affect thermal treatment could help optimize waste processing at wastewater treatment plants.

2024 Journal of Environmental Management 11 citations
Article Tier 2

Changes in physicochemical and leachate characteristics of microplastics during hydrothermal treatment of sewage sludge

Researchers examined hydrothermal treatment of sewage sludge containing microplastics and found that while the process degraded polyethylene, polystyrene, and PET to varying degrees, it also generated potentially harmful leachates, highlighting trade-offs in this treatment approach.

2022 Water Research 86 citations
Article Tier 2

Microplastics in sewage sludge destined to anaerobic digestion: The potential role of thermal pretreatment

Researchers found that thermal pretreatment of sewage sludge at 120°C did not degrade conventional PET microplastics but did alter biodegradable microplastics, which also boosted methane production during anaerobic digestion, raising concerns about how different microplastic types behave in sludge treatment.

2022 Chemosphere 27 citations
Article Tier 2

Unraveling Co-Pyrolysis Mechanisms for Municipal Sludge and Microplastics: Thermodynamic, Kinetic, and Product Insights

Wastewater treatment plants produce large quantities of sewage sludge, which is often contaminated with microplastics from household and industrial sources. This study tested whether co-pyrolyzing sludge with polyethylene (HDPE) or PET plastic waste at high temperatures could improve energy recovery while processing microplastics. Adding 30% HDPE maximized the overall pyrolysis efficiency and changed the chemical reaction pathways, while PET had stronger facilitating effects at mid-range temperatures. The research suggests that co-pyrolysis could serve the dual purpose of sludge disposal and microplastic destruction, though the altered reaction kinetics and product mixtures require careful management.

2026 Processes
Article Tier 2

Microplastic Degradation through Thermal Hydrolysis in Sewage Sludge and Its Impact on the Anaerobic Process

Researchers found that thermal hydrolysis pretreatment of sewage sludge reduced microplastic concentrations from 206 particles/g to lower levels, with approximately 54% of microplastics initially in solid phase, and examined the implications for sludge management and microplastic fate.

2025 ACS ES&T Water
Article Tier 2

Fate of microplastic during pyrolysis of sewage sludge

Researchers investigated what happens to microplastics embedded in sewage sludge when sludge is treated by pyrolysis, a high-temperature thermochemical process. Pyrolysis effectively destroyed most microplastic particles, but some residual polymer-derived compounds partitioned into the pyrolysis products.

2024 Zenodo (CERN European Organization for Nuclear Research)
Article Tier 2

MicroplasticDegradation through Thermal Hydrolysisin Sewage Sludge and Its Impact on the Anaerobic Process

Researchers investigated the fate of microplastics in sewage sludge during thermal hydrolysis pretreatment and found that temperatures of 140-180°C significantly degraded microplastics while also affecting subsequent anaerobic biogas production from the treated sludge.

2025 Figshare
Article Tier 2

The Potential of Ozonation to Reduce Impact of Waste Sludge-Entrapped Microplastics to Biogas Production

Wastewater treatment plants concentrate microplastics from sewage into the resulting sludge, and this study tested whether ozonation could reduce the harm those microplastics cause during anaerobic digestion used to produce biogas. The findings showed that PET and polypropylene microplastics alter methane yields from sludge digestion in concentration-dependent ways, and that ozone pretreatment partially mitigates the inhibition caused by polypropylene — though the interactions are complex and require further optimization before widespread use.

2024 Ozone Science and Engineering 3 citations
Article Tier 2

Fate of microplastic during pyrolysis of sewage sludge

Researchers examined how pyrolysis as a sewage sludge treatment method affects the fate of embedded microplastics, finding that thermal treatment largely destroys plastic particles. However, some polymer-derived volatile compounds transferred to pyrolysis gases and oils, suggesting that microplastic destruction does not eliminate all associated chemical risks.

2024 Zenodo (CERN European Organization for Nuclear Research)
Article Tier 2

Elucidating degradation properties, microbial community, and mechanism of microplastics in sewage sludge under different terminal electron acceptors conditions

Researchers found that the type of terminal electron acceptor significantly controls the degradation rates and pathways of polylactic acid, polyvinyl chloride, and polyhydroxyalkanoate microplastics in sewage sludge, with aerobic conditions promoting faster degradation than anaerobic alternatives.

2021 Bioresource Technology 32 citations
Article Tier 2

Microplastics Removal from Municipal Wastewater Through Oxide-Biological Processes. Phase 1: Preliminary Fragmentation of Microplastics from Wastewater and Aerobic Pre-conditioning of Wastewater with Activated Sludge

Researchers tested a combined treatment approach for removing microplastics from municipal wastewater, involving mechanical fragmentation followed by biological treatment with activated sludge. The preliminary results suggest that oxidative pre-treatment can reduce microplastic particle size, potentially making them more amenable to biological breakdown in wastewater systems.

2023 E3S Web of Conferences 1 citations
Article Tier 2

Microplastics Mitigation in Sewage Sludge through Pyrolysis: The Role of Pyrolysis Temperature

The effect of pyrolysis on reducing microplastic content in sewage sludge was investigated in a lab-scale study evaluating multiple pyrolysis temperature conditions. Pyrolysis effectively degraded microplastic particles in sludge, with higher temperatures achieving greater microplastic reduction, positioning pyrolysis as a viable treatment for managing microplastic-laden organic waste.

2020 Environmental Science & Technology Letters 151 citations
Article Tier 2

Wet oxidation technology can significantly reduce both microplastics and nanoplastics

Researchers evaluated wet oxidation technology at an industrial scale for its ability to reduce micro- and nanoplastic contamination in organic waste processing. The study found that wet oxidation decreased the total mass concentration of microplastics and nanoplastics by 94.8% to 98.6%, completely removing fibers and certain polymer types while still enabling recovery of organic resources.

2024 Water Research 12 citations
Article Tier 2

Medium-Low Temperature Conditions Induce the Formation of Environmentally Persistent Free Radicals in Microplastics with Conjugated Aromatic-Ring Structures during Sewage Sludge Pyrolysis

Researchers found that incomplete pyrolysis of sewage sludge at medium-low temperatures left residual microplastics containing high levels of environmentally persistent free radicals, particularly from polystyrene and other aromatic-ring plastics. Increasing pyrolysis temperature reduced microplastic residues but required tradeoffs with other sludge treatment objectives.

2022 Environmental Science & Technology 49 citations
Article Tier 2

Microplastic Degradation in Sewage Sludge by Hydrothermal Carbonization: Efficiency and Mechanisms

Researchers evaluated hydrothermal carbonization as a method for degrading microplastics in sewage sludge. The study found that treatment at 260 degrees Celsius achieved a 79% reduction in microplastic concentrations, and investigated the decomposition mechanisms for different polymer types. The findings suggest that hydrothermal carbonization could be an effective approach for removing microplastics from sewage sludge before environmental disposal.

2022 Chemosphere 74 citations
Article Tier 2

Fate, characteristics, and potential threat of microplastics in sludge under various dewatering treatments

Researchers compared four different sludge dewatering treatments used at wastewater plants and examined how each process affected the microplastics trapped in the sludge. They found that advanced oxidation treatments altered the surface properties of the microplastics and increased their ability to absorb heavy metals. The findings raise concerns that certain sludge treatment methods could make microplastics more environmentally hazardous when the treated sludge is disposed of or reused.

2025 Journal of Environmental Management 3 citations
Article Tier 2

Microplastics degradation through hydrothermal liquefaction of wastewater treatment sludge

Researchers tested whether hydrothermal liquefaction (HTL) — a high-temperature, high-pressure process that converts sewage sludge into bio-crude oil — could also destroy microplastics in the sludge, finding it reduced microplastic numbers by 76% and mass by 97%, with no microplastics detected in the bio-crude product. This suggests HTL could serve a dual purpose: producing renewable fuel while significantly reducing microplastic pollution from the sludge that would otherwise be spread on farmland.

2022 Journal of Cleaner Production 90 citations