Papers

61,005 results
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Article Tier 2

Recent Developments in the Application of Ultrasonication in Pre-Treatment of Municipal Sewage Sludge

Not relevant to microplastics — this paper reviews ultrasonication as a pre-treatment method for municipal sewage sludge to improve anaerobic digestion efficiency, with no focus on plastic contamination.

2023 Journal of Ecological Engineering 8 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
Review Tier 2

Microplastics in Sewage Sludge: A review

This review examines the presence and fate of microplastics in sewage sludge from municipal wastewater treatment plants, a topic that has received less attention than microplastics in the water treatment line. The study highlights that agricultural application of sewage sludge is a primary source of microplastic contamination in soils, and provides a comprehensive overview of detection methods, concentrations, and the environmental implications of sludge-borne microplastics.

2023 Environmental Science and Pollution Research 64 citations
Article Tier 2

Microplastic retention in small and medium municipal wastewater treatment plants and the role of the disinfection

Researchers measured how effectively small and medium wastewater treatment plants removed microplastics at each treatment stage, including disinfection. Treatment plants removed over 95% of incoming microplastics, but the disinfection step (UV or chlorination) had minimal effect on particle removal. The bulk of microplastics that do pass through treatment are concentrated in sludge, which when spread on farmland returns microplastics to agricultural soils.

2021 Environmental Science and Pollution Research 23 citations
Article Tier 2

Degradation of common polymers in sewage sludge purification process developed for microplastic analysis

Researchers developed a three-step sewage sludge purification method and tested its effects on seven common plastic types. Most polymers survived largely intact, supporting the method's use for microplastic analysis, though some materials showed minor surface changes.

2020 Environmental Pollution 26 citations
Article Tier 2

Microplastic removal and management strategies for wastewater treatment plants

This review examines how well different wastewater treatment technologies remove microplastics and what management strategies can improve performance. While conventional treatment plants can remove a large percentage of microplastics from water, the particles often end up concentrated in sewage sludge that gets applied to farmland. The study highlights the need for advanced treatment options and better management of biosolids to prevent microplastics from simply being transferred from water to soil.

2023 Chemosphere 133 citations
Article Tier 2

Fate of microplastics in sewage sludge and in agricultural soils

Researchers reviewed how microplastics accumulate in sewage sludge at wastewater treatment plants and then spread into agricultural soils when that sludge is applied as fertilizer, finding that sludge treatment processes can alter microplastic size and shape but do not eliminate them. The review calls for standardized methods to study how different sludge treatments affect microplastic properties and their downstream risks to soil health.

2023 TrAC Trends in Analytical Chemistry 52 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

Effects of mesophilic and thermophilic anaerobic digestion of sewage sludge on different polymers: Perspectives on the potential of the treatment to degrade microplastics

Researchers tested whether mesophilic and thermophilic anaerobic digestion of sewage sludge could degrade common microplastic polymers. While they observed some surface changes and degradation signs in certain plastics, the process could not comprehensively break down any of the eight polymer types tested. The study concludes that anaerobic digestion of sewage sludge, under the conditions tested, is not an effective method for eliminating microplastics before sludge is applied to soil.

2023 The Science of The Total Environment 31 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

Sampling, pre-treatment, and identification methods of microplastics in sewage sludge and their effects in agricultural soils: a review

This review examines methods for sampling, pre-treating, and identifying microplastics in sewage sludge, which accumulates microplastics removed during wastewater treatment. Researchers found that standardized protocols for sludge analysis are still lacking, making it difficult to compare results across studies. The study also highlights that when microplastic-laden sludge is applied to agricultural soils, it may introduce persistent plastic contamination into terrestrial ecosystems.

2021 Environmental Monitoring and Assessment 65 citations
Article Tier 2

Microplastics in sewage sludge: Distribution, toxicity, identification methods, and engineered technologies

This review examines how microplastics accumulate in sewage sludge from wastewater treatment plants, which then becomes a major pathway for spreading these particles into the environment. Researchers found that sludge can contain extremely high concentrations of microplastics, ranging from thousands to hundreds of thousands of particles per kilogram. The study evaluates current detection methods and emerging technologies for removing microplastics from sludge before it is applied to agricultural land or disposed of.

2022 Chemosphere 106 citations
Article Tier 2

Fate of microplastics during conventional and hydrothermal treatments of sewage sludge: a short review

This review examines the fate of microplastics during conventional and hydrothermal treatment of sewage sludge, noting that approximately 90% of microplastics entering wastewater treatment plants are retained in sludge. Researchers found that while conventional disposal routes concentrate microplastics in sludge destined for land application, hydrothermal treatments offer potential pathways to degrade or transform microplastics, though the efficiency and byproducts of these processes require further investigation.

2025 IOP Conference Series Earth and Environmental Science
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

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

Aging and mitigation of microplastics during sewage sludge treatments: An overview

Researchers reviewed how microplastics change and break down during sewage sludge treatment processes such as composting, anaerobic digestion, and thermal treatment. They found that while some treatment methods can reduce microplastic levels, others may actually fragment particles into smaller, potentially more harmful sizes. The study highlights the importance of optimizing sludge treatment to prevent microplastics from reaching agricultural soils when sludge is applied as fertilizer.

2024 The Science of The Total Environment 24 citations
Article Tier 2

Contemporary Drift in Emerging Micro(nano)plastics Removal and Upcycling Technologies from Municipal Wastewater Sludge: Strategic Innovations and Prospects

This review evaluates both conventional and advanced methods for removing microplastics from sewage sludge before it is applied to farmland as fertilizer. Current treatment processes like anaerobic digestion and composting reduce but do not eliminate microplastics, and some methods can actually fragment larger plastics into more numerous smaller pieces. The authors identify emerging technologies and upcycling strategies that could better address this pathway of microplastic contamination in agricultural soils.

2023 Current Pollution Reports 36 citations
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

Impact of preozonation on biogas potential of PVC microplastics-containing waste sludge

Researchers evaluated the impact of preozonation on anaerobic digestion of wastewater sludge contaminated with PVC microplastics, measuring biogas and methane yields to determine whether ozone pretreatment could overcome the inhibitory effect that insoluble PVC particles exert on sludge-degrading microorganisms.

2022 Global NEST Journal 3 citations
Article Tier 2

UV Light Causes Structural Changes in Microplastics Exposed in Bio-Solids

Researchers tested whether UV light could weaken microplastics found in sewage sludge before they enter the environment. UV exposure combined with heat caused structural breakdown in polypropylene, polyethylene, and PET plastics, especially when treated in bio-solid (sewage sludge) mixtures. This approach could help microplastics degrade faster once released into the environment, potentially reducing how long they persist in soil and water.

2023 Polymers 35 citations
Article Tier 2

A method for the characterisation of microplastics in sludge

Researchers developed a method for detecting and characterizing microplastics in sewage sludge, which concentrates the majority of microplastics removed during wastewater treatment. This method is important because sludge is widely spread on agricultural land, making it a key pathway for microplastics entering soils.

2019 MethodsX 23 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