Papers

61,005 results
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Article Tier 2

The Occurrence and Risk Assessment of Microplastics: different treatment technologies for wastewater treatment plants in Oman

A study of three wastewater treatment plants in Oman — using conventional activated sludge, membrane bioreactor, and sequencing batch reactor technologies — quantified and characterized MPs at multiple treatment stages, including sludge. Membrane bioreactor technology achieved the best MP removal from effluent, but all plants concentrated MPs in sludge, highlighting an underregulated route for microplastic release back into the environment.

2023 Global NEST International Conference on Environmental Science & Technology
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

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

Distribution and removal mechanism of microplastics in urban wastewater plants systems via different processes

Researchers compared the microplastic removal efficiency of three wastewater treatment technologies and found that the anaerobic-anoxic-oxic process achieved the highest removal rate at 83.9%. Most microplastics were transferred to sludge during primary and secondary treatment stages, with dehydrated sludge containing significant concentrations. The study highlights that while wastewater treatment plants effectively intercept most microplastics, they also redistribute contamination to sludge, which may become a secondary pollution source.

2023 Environmental Pollution 65 citations
Article Tier 2

Identification and quantification of microplastics in wastewater treatment plant effluent: Investigation of the fate and biological effects

This study identified and quantified microplastics in wastewater treatment plant effluents and sludge, finding particles in all samples with fibers being the dominant type. The research contributes to understanding how much microplastic reaches surface waters via wastewater discharge and how much is captured in sludge that is subsequently applied to agricultural land.

2018 Griffith Research Online (Griffith University, Queensland, Australia) 4 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

Removal of Microplastic Pollution through Waste Water Treatment: A Review

This review examines how wastewater treatment plants reduce microplastic contamination, comparing biological and advanced treatment methods and highlighting that residual microplastics in sewage sludge applied to agricultural land remain a significant pathway for environmental release.

2022 Journal for Research in Applied Sciences and Biotechnology 7 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

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

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

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

Fate of microplastics in wastewater treatment plants and their environmental dispersion with effluent and sludge

Researchers tracked microplastics through a wastewater treatment plant and found 12 different polymer types in effluents and sludge, with smaller particles (25–104 μm) most abundant and fibres displaying lower sizes than fragments. The study demonstrates that WWTPs do not fully remove microplastics and that processed sludge marketed as soil amendment carries plastic contamination.

2019 Environmental Pollution 589 citations
Article Tier 2

Fate of Microplastic Pollution Along the Water and Sludge Lines in Municipal Wastewater Treatment Plants

Researchers evaluated microplastic abundance and distribution across three municipal wastewater treatment plants using different treatment technologies. The study found that all three plants achieved greater than 97% microplastic removal along the water treatment line, with microplastics concentrating in the sludge fraction, underscoring the important role of sludge treatment in sequestering microplastics from wastewater.

2025 Microplastics 6 citations
Article Tier 2

Microplastics in Wastewater and Environmental Aspects

This review covers the occurrence and environmental behavior of microplastics in wastewater, examining removal efficiencies across different treatment technologies and the fate of plastics that pass through or are retained in sludge. The authors assess tertiary filtration and coagulation as the most effective removal steps and highlight sludge land application as a major pathway for microplastics entering agricultural soils.

2024 JORDANIAN JOURNAL OF ENGINEERING AND CHEMICAL INDUSTRIES (JJECI)
Article Tier 2

Configuration-driven microplastic fate in full-scale sewage sludge treatment and opportunities for system-level mitigation

Researchers examined how different treatment configurations in wastewater plants shape the types and concentrations of microplastics that end up in sewage sludge — the solid byproduct that is frequently spread on agricultural land as fertilizer. Microplastic concentrations in final sludge ranged from 617 to 936 particles per gram of dry solids, with fine fragments under 100 micrometers dominating, and the specific sequence of thickening, digestion, and dewatering steps significantly influenced which polymer types were retained. Since sludge application is a major route for microplastics to enter farmland, optimizing treatment processes could meaningfully reduce environmental contamination.

2026 Journal of Environmental Management
Article Tier 2

Approaching the environmental problem of microplastics: Importance of WWTP treatments

This review examines the role of wastewater treatment plants as sources and sinks of microplastics, noting that while treatment removes significant quantities, remaining particles concentrate in sewage sludge which is then applied to agricultural land as fertilizer. The authors survey available technologies for improving microplastic removal and call for better policy to address this gap.

2020 The Science of The Total Environment 262 citations
Review Tier 2

The Effect of Wastewater Treatment Plants on Retainment of Plastic Microparticles to Enhance Water Quality—A Review

This review examined how well wastewater treatment plants remove microplastics, finding that most conventional systems achieve high removal rates but still discharge significant plastic quantities in treated effluent and sludge. Improving treatment efficiency and preventing sludge application to farmland are key strategies for reducing microplastic release.

2021 Journal of Environmental Protection 12 citations
Article Tier 2

Microplastics removal through water treatment plants: Its feasibility, efficiency, future prospects and enhancement by proper waste management

Researchers reviewed over 80 studies on water treatment plant performance and found microplastic removal ranges widely — from 16% in basic primary treatment up to near 100% with advanced membrane systems — but a major flaw is that removed microplastics concentrate in sludge, which can re-enter the environment. The review recommends optimizing coagulants and sludge treatment to prevent microplastics from simply being relocated rather than eliminated.

2021 Environmental Challenges 181 citations
Article Tier 2

Technologies for the Removal of Microplastics from Wastewater: A Short Review

This review compares wastewater treatment technologies for removing microplastics, finding that membrane bioreactors and advanced filtration systems achieve the highest removal efficiencies (>95%) but that MPs accumulating in sludge may re-enter the environment through biosolid disposal. The analysis underscores that no current treatment system completely prevents MP discharge and that sludge management is a critical but underaddressed pathway to the environment.

2023 Global NEST International Conference on Environmental Science & Technology 2 citations
Article Tier 2

Conventional and Advanced Treatment Technologies for Microplastics in Water Treatment Facilities

This review evaluated both conventional and advanced water treatment methods for removing microplastics from wastewater. Researchers found that while techniques like coagulation, filtration, and membrane bioreactors can remove most microplastics, treatment plants still release significant quantities due to the sheer volume of water processed, and microplastic-laden sludge applied to farmland creates another pathway for environmental contamination.

2024 Preprints.org 6 citations
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

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

Microplastic Pollution via Wastewater Effluent and Sewage Sludge: Special Focus on Microplastic Fibres in Compost

Researchers measured microplastic concentrations in treated wastewater effluent and sewage sludge from treatment plants, finding that despite high MP removal rates, large daily discharge volumes still release substantial quantities of MPs into the environment. Sludge applied to agricultural land was identified as a major secondary MP pollution pathway.

2025 Water Air & Soil Pollution 2 citations
Article Tier 2

Tracing the fate of microplastic in wastewater treatment plant: A multi-stage analysis of treatment units and sludge

Researchers tracked microplastics through every stage of a wastewater treatment plant and found that while treatment removes many particles from the water, most end up concentrated in the leftover sludge. Fibers and fragments were the most common shapes, made primarily of polyester and polyethylene. Since treated sludge is often spread on farmland, this creates a pathway for microplastics to enter soil and potentially the food chain.

2023 Environmental Pollution 60 citations