Papers

61,005 results
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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

Effects of chronic exposure to different sizes and polymers of microplastics on the characteristics of activated sludge

Researchers studied how 60 days of exposure to different sizes and types of microplastics affected activated sludge at wastewater treatment plants. Millimeter-sized particles dramatically reduced sludge dewaterability by up to 47.7%, mainly through physical disruption of sludge flocs. Nano-sized particles also impaired sludge performance by inhibiting microbial activity and altering the composition of extracellular polymeric substances.

2021 The Science of The Total Environment 67 citations
Article Tier 2

Transfer of microplastics in sludge upon Fe(II)-persulfate conditioning and mechanical dewatering

Researchers investigated how Fe(II)-persulfate conditioning and mechanical dewatering of sewage sludge affect microplastic fate, finding that these processes can fragment larger plastic particles, increasing the number of smaller microplastics that may subsequently be released during sludge land application.

2022 The Science of The Total Environment 26 citations
Article Tier 2

Transport and accumulation of microplastics through wastewater treatment sludge processes

Researchers tracked microplastic concentrations through each stage of wastewater treatment sludge processing — including thickening, anaerobic digestion, and dewatering — finding that each step altered MP abundance and size distribution, with digestion fragmenting some particles into smaller pieces rather than eliminating them.

2021 Chemosphere 169 citations
Article Tier 2

Circulation of microplastics in a municipal wastewater treatment plant with multiphase activated sludge

Researchers tracked the circulation of microplastics through a municipal wastewater treatment plant, from raw wastewater through sludge processing. They found that most microplastics accumulated in sewage sludge at high concentrations, and that leachate from sludge treatment recycled microplastics back into the treatment process. The study highlights how wastewater treatment plants can inadvertently redistribute microplastics rather than fully removing them from the waste stream.

2024 Desalination and Water Treatment 10 citations
Article Tier 2

The Effects of Microplastics on Floc Formation, Nutrient Removal and Settleability in Wastewater Treatment

Researchers examined the interactions of microplastics with activated sludge in wastewater treatment plants, investigating effects on floc formation, nutrient removal efficiency, and settleability to understand how microplastic contamination may compromise treatment performance.

2024
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

Sludge drying and dewatering processes influence the abundance and characteristics of microplastics in wastewater treatment plants

Researchers evaluated how sludge drying and dewatering processes affect microplastic abundance and characteristics at two wastewater treatment plants in Morocco, collecting samples across multiple treatment stages. The study identified specific sludge processing steps that concentrate or transform microplastics, with implications for managing microplastic emissions when treated sludge is land-applied.

2023 Chemosphere 29 citations
Article Tier 2

The Effects of Microplastics on Floc Formation, Nutrient Removal and Settleability in Wastewater Treatment

Researchers investigated how microplastics affect floc formation, nutrient removal, and settleability in wastewater treatment systems, examining the mechanisms by which these ubiquitous anthropogenic pollutants entering via packaging, cosmetics, and other production sectors disrupt activated sludge processes.

2024
Article Tier 2

Microplastic Fibers Deteriorate Dewaterability of Waste Activated Sludge through Alteration of Extracellular Proteome and Extracellular Polymeric Substance Structures

Researchers investigated how microplastic fibres affect the dewaterability of waste activated sludge (WAS) and found that fibres significantly deteriorated sludge dewatering performance by altering the extracellular proteome and modifying extracellular polymeric substance (EPS) structures. The study revealed that microplastic fibre exposure changed the protein composition and biophysical properties of EPS, creating a mechanistic link between fibre contamination and impaired sludge management in wastewater treatment.

2025 Environmental Science & Technology
Article Tier 2

Effect evaluation of microplastics on activated sludge nitrification and denitrification

Researchers found that microplastics entering wastewater treatment plants interfere with the nitrification and denitrification processes carried out by activated sludge microbes, potentially reducing the effectiveness of nutrient removal in sewage treatment. This effect could undermine water quality if microplastic loads in wastewater continue to increase.

2019 The Science of The Total Environment 172 citations
Article Tier 2

Response of aerobic granular sludge under polyethylene microplastics stress: Physicochemical properties, decontamination performance, and microbial community

Researchers investigated the impact of polyethylene microplastics on aerobic granular sludge used in wastewater treatment. The study found that microplastics significantly disrupted sludge structure, settling properties, and enzyme activities related to denitrification and phosphorus removal, with increased reactive oxygen species and cell membrane damage at higher concentrations.

2022 Journal of Environmental Management 79 citations
Article Tier 2

Exploring the influence of sludge dewatering agents on Microplastic aging under hydrothermal treatment: Insights from Polylactic Acid microplastics

This study examined how industrial wastewater sludge treatment chemicals (dewatering agents) interact with hydrothermal processing to alter the physical and chemical properties of polylactic acid (PLA) microplastics in sludge. The findings matter because different treatment chemistries transform microplastic surfaces in distinct ways — affecting their porosity, reactivity, and persistence — which has implications for how microplastics behave after leaving wastewater treatment facilities.

2023 Environmental Research 7 citations
Article Tier 2

Deciphering the inhibition mechanisms of microplastics on the full-stage sludge anaerobic digestion via enrichment to anaerobic microbes and toxicity of released compounds

This study found that microplastics in sewage sludge significantly interfere with the waste treatment process by reducing the activity of key microorganisms needed to break down waste. More than half of the negative effect came from toxic chemicals released when microplastic particles rub against sludge, and the disrupted treatment also increased the risk of spreading antibiotic-resistant bacteria.

2024 Journal of Hazardous Materials 21 citations
Article Tier 2

Effects of chemical pretreatments on microplastic extraction in sewage sludge and their physicochemical characteristics

This study evaluated different chemical pretreatment methods for extracting microplastics from sewage sludge, finding that some treatments can alter the physical and chemical properties of plastic particles in ways that affect identification. Choosing the right extraction method is important for accurately characterizing microplastic contamination in biosolids.

2019 Water Research 166 citations
Article Tier 2

Effects of microplastics on the properties of different types of sewage sludge and strategies to overcome the inhibition: A review

This review examined how microplastics trapped in sewage sludge during wastewater treatment affect sludge properties, microbial communities, and treatment efficiency, while discussing strategies to overcome microplastic-induced inhibition of sludge processing.

2023 The Science of The Total Environment 44 citations
Article Tier 2

Revealing the Mechanisms of Polyethylene Microplastics Affecting Anaerobic Digestion of Waste Activated Sludge

Researchers studied how polyethylene microplastics affect the anaerobic digestion of sewage sludge, a common wastewater treatment process. They found that higher concentrations of microplastics significantly reduced methane production by disrupting microbial communities and enzyme activities essential for digestion. The study reveals that microplastic contamination in wastewater systems can undermine the efficiency of sludge treatment and biogas generation.

2019 Environmental Science & Technology 351 citations
Article Tier 2

Microplastics in Sewage Sludge: Effects of Treatment

This study examined the effects of various sewage sludge treatment processes on microplastic content, finding that treatment methods differ substantially in their ability to reduce microplastic concentrations before sludge is disposed of or land-applied.

2016 Environmental Science & Technology 1019 citations
Article Tier 2

Effects of microplastics on substance transformation, sludge characteristics, toxicological effect, and microbial communities in different biochemical sludge systems: A review

This review synthesizes evidence that microplastics impair the biological and physical processes in wastewater treatment sludge systems, inhibiting nutrient removal, disrupting microbial communities, and degrading sludge structure—with smaller particles and higher concentrations causing greater damage. Because sludge is widely applied to agricultural land, any microplastic-driven impairment of treatment efficiency also increases the risk of plastic particles and associated pollutants reaching soils and food crops.

2023 Critical Reviews in Environmental Science and Technology 10 citations
Article Tier 2

Mechanisms underlying the detrimental impact of micro(nano)plastics on the stability of aerobic granular sludge: Interactions between micro(nano)plastics and extracellular polymeric substances

Researchers found that both micro- and nanoplastics at realistic concentrations harmed the performance of aerobic granular sludge, a technology used for wastewater treatment, by reducing its ability to remove nitrogen. The plastic particles interacted with the sticky substances that hold the sludge granules together, weakening their structural integrity. The study reveals a specific mechanism by which plastic pollution can undermine wastewater treatment systems that communities rely on for clean water.

2024 Journal of Hazardous Materials 31 citations
Article Tier 2

Molecular properties and biotoxicity of dissolved organic matter leached from microplastic (MP-DOM) during typical hydrothermal treatment of sewage sludge

Researchers investigated the dissolved organic matter that leaches from microplastics during sewage sludge treatment processes like thermal hydrolysis. Different plastic types released chemically distinct compounds, some of which showed toxicity to aquatic organisms. The findings highlight that microplastics are not just physical pollutants but also release harmful chemical byproducts during waste treatment.

2023 The Science of The Total Environment 30 citations
Article Tier 2

Amplifiers of environmental risk of microplastics in sewage sludge: Thermal drying treatment

Researchers found that thermal drying of sewage sludge increased microplastic abundance by approximately 10-fold compared to undried sludge, with enhanced fragmentation into smaller particles. This finding identifies thermal drying as a treatment process that amplifies rather than reduces the environmental risk of microplastics in sludge.

2023 The Science of The Total Environment 15 citations
Article Tier 2

Behavior and flow of microplastics during sludge treatment in Japan

Sampling of two Osaka wastewater treatment plants found microplastics at every stage of the sludge treatment process, with 13 polymer types identified; concentration increased through dewatering, but the total MP load in final biosolids was lower than in raw sludge.

2024 The Science of The Total Environment 8 citations
Article Tier 2

Impact of Polyethylene Terephthalate Microplastics on Aerobic Granular Sludge Structure and EPS Composition in Wastewater Treatment

Researchers investigated how PET microplastics affect the structure and function of aerobic granular sludge used in wastewater treatment. Higher microplastic concentrations led to changes in granule size, altered the composition of extracellular polymeric substances, and shifted microbial community structure. The findings suggest that microplastic contamination in wastewater could compromise the stability and efficiency of biological treatment processes.

2025 Water 6 citations