Papers

61,006 results
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Article Tier 2

Analysis of the potential role of microplastics as transporters of microorganisms in activated sludge

Researchers investigated whether microplastic microbeads present in wastewater can support microbial biofilm formation and facilitate the spread of microorganisms in activated sludge treatment systems. Microplastics from multiple polymer types readily hosted biofilm development, with bacterial communities differing between plastic types, suggesting microplastics can serve as microbial vectors in wastewater treatment.

2025 Desalination and Water Treatment 2 citations
Article Tier 2

Occurrence of Microplastics in Waste Sludge of Wastewater Treatment Plants: Comparison between Membrane Bioreactor (MBR) and Conventional Activated Sludge (CAS) Technologies

Microplastics were compared in sludge from wastewater treatment plants using conventional activated sludge and membrane bioreactor technologies, finding that both produced sludge with significant plastic contamination and that the MBR system showed somewhat different microplastic profiles. The results indicate that sludge disposal is a key route by which microplastics captured in treatment plants are transferred to agricultural land.

2022 Membranes 63 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

Abundance of Microplastics in Wastewater Treatment Sludge

This review found that wastewater treatment plants trap a substantial proportion of incoming microplastics into sludge, with abundance varying widely by region based on population density, urbanization, and treatment technology, raising concerns about the land application of microplastic-laden biosolids.

2022 Journal of Human Earth and Future 39 citations
Article Tier 2

[Microplastics in wastewater treatment: current status and future trends].

This review summarizes current research on microplastic occurrence, removal, and fate in wastewater treatment plants, noting that while plants capture most microplastics in activated sludge, significant numbers still escape into effluent. The sludge itself then becomes a major pathway for microplastics to enter agricultural soils when applied as fertilizer. Future treatment improvements and sludge management policies are needed to reduce these release pathways.

2022 PubMed 4 citations
Article Tier 2

Current progress of continuous-flow aerobic granular sludge: A critical review.

This review examines the development of continuous-flow aerobic granular sludge technology for wastewater treatment, which offers advantages over conventional systems in terms of compactness and energy efficiency. While focused on wastewater engineering, such systems are relevant to microplastic removal since wastewater treatment plants are a major pathway for microplastics entering the environment.

2023 The Science of the total environment
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

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

Variation in microplastic concentration, characteristics and distribution in sewage sludge & biosolids around the world

Researchers systematically reviewed 65 studies on microplastics in sewage sludge and biosolids from wastewater treatment plants around the world. They found that while treatment processes remove 57% to 99% of microplastics from wastewater, the removed particles concentrate in sludge that is often applied to agricultural land. The review highlights that land application of biosolids may be a significant, underappreciated pathway for microplastic pollution in soils.

2023 The Science of The Total Environment 95 citations
Article Tier 2

Variation in microplastic concentration, characteristics and distribution in sewage sludge & biosolids around the world

This review synthesizes global data on microplastic concentrations, characteristics, and distribution in sewage sludge and biosolids, drawing on studies showing wastewater treatment works remove 57-99% of incoming microplastics, concentrating them in sludge byproducts. The review highlights the significance of this concentration pathway and what happens to these microplastics when sludge is applied to land or otherwise managed.

2025 Figshare
Article Tier 2

Microplastics in Sewage Sludge: Worldwide Presence in Biosolids, Environmental Impact, Identification Methods and Possible Routes of Degradation, Including the Hydrothermal Carbonization Process

This review examines the worldwide presence of microplastics in sewage sludge and biosolids, along with their environmental impact when applied to agricultural land. Researchers found that wastewater treatment plants capture roughly 90% of incoming microplastics in sludge, but land application of biosolids then redistributes these particles into soils, highlighting the need for better degradation methods.

2024 Energies 15 citations
Article Tier 2

Microplastics in Sewage Sludge: A Known but Underrated Pathway in Wastewater Treatment Plants

This review finds that wastewater treatment plants effectively transfer microplastics from effluent into sewage sludge, creating a significant but underrated pathway for MP contamination when sludge is applied to agricultural soils.

2021 Sustainability 46 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

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

Occurrence, effect, and fate of residual microplastics in anaerobic digestion of waste activated sludge: A state-of-the-art review

This review assessed the occurrence, behavior, and fate of microplastics in anaerobic digestion of waste activated sludge, finding that MPs survive digestion largely intact but can affect methane production and microbial community composition, and that digestate land application remains a major pathway for releasing sludge-retained MPs to soil.

2021 Bioresource Technology 100 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

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

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

A review of methods for mitigating microplastic contamination in biosolids from wastewater treatment plants before agricultural soil application

This review examines methods for reducing microplastic contamination in biosolids from wastewater treatment plants before they are applied to agricultural soils. Researchers assessed physical, physicochemical, and biological approaches and found that each has inherent limitations, from inconsistent microbial degradation efficiency to filter design constraints. The study suggests that combining multiple methods at different intervention points within the treatment process offers the most promising path toward effective microplastic mitigation.

2024 The Science of The Total Environment 13 citations
Article Tier 2

Remediation and Management of Sewage Sludge

This review covers technologies for treating and managing municipal sewage sludge, including anaerobic digestion, composting, and thermal methods. Sewage sludge is one of the main pathways through which microplastics in wastewater become concentrated and then spread to agricultural land when sludge is used as fertilizer.

2023 Sustainable development 1 citations
Article Tier 2

Activated sludge in municipal wastewater treatment plant serves as a potentially source of microplastics: Source apportionment based on APCS-MLR and PMF receptor models

Researchers investigating a combined-sewer wastewater treatment plant found that activated sludge — the microbial biomass used to treat sewage — is a concentrated reservoir of microplastics, with small fragments dominating, and used source apportionment modeling to trace their origins. This matters because the disposal of microplastic-laden sewage sludge onto agricultural land is a major pathway for plastics entering soils.

2026 Journal of Hazardous Materials
Article Tier 2

Sewage sludge as a source of microplastics in the environment: A review of occurrence and fate during sludge treatment

This review assessed how wastewater treatment plants concentrate microplastics from influent into sludge, estimating that sewage sludge applied to agricultural land represents a major secondary pathway for MPs entering terrestrial ecosystems, with estimated releases of millions to billions of particles per hectare.

2021 Journal of Environmental Management 139 citations
Article Tier 2

Efficient removal of microplastic particles from wastewater through formation of heteroagglomerates during the activated sludge process

Microplastic particles were efficiently removed from wastewater using a novel treatment process, demonstrating high removal rates across different plastic sizes and polymer types. The technology contributes to the toolkit for preventing microplastic discharge from wastewater treatment plants into receiving waters.

2025 Journal of Hazardous Materials 1 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