Papers

20 results
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Article Tier 2

Preliminary prospections on the fate of microplastics during vermicomposting of sewage sludge

Researchers tracked microplastic abundance through the vermicomposting stages of sewage sludge — from fresh sludge through aged sludge, vermicompost, and earthworm castings — finding a 52% reduction in microplastic concentration from initial sludge to vermicompost when particles were classified by size, color, and polymer type using micro-Raman spectroscopy.

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

Preliminary prospections on the fate of microplastics during vermicomposting of sewage sludge

Researchers tracked microplastic abundance through the vermicomposting stages of sewage sludge — from fresh sludge through aged sludge, vermicompost, and earthworm castings — finding a 52% reduction in microplastic concentration from initial sludge to vermicompost when particles were classified by size, color, and polymer type using micro-Raman spectroscopy.

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

Vermicomposting leads to more abundant microplastics in the municipal excess sludge

Researchers found that vermicomposting of municipal excess sludge leads to increased microplastic concentrations in the treated material compared to the input sludge, raising concerns that this widely-used organic amendment technology may concentrate and spread microplastic contamination in soils.

2022 Chemosphere 23 citations
Article Tier 2

Transport and fate of microplastics in constructed wetlands: A microcosm study

This study tested microplastic removal in constructed wetlands using different particle shapes and sizes, finding 81.6% removal in surface flow systems and 100% removal in horizontal subsurface flow systems, with biofilm attachment and physical filtration as key retention mechanisms.

2021 Journal of Hazardous Materials 144 citations
Article Tier 2

Fate and removal of microplastics in unplanted lab-scale vertical flow constructed wetlands

Laboratory-scale unplanted vertical flow constructed wetlands were shown to remove microplastics from wastewater, with removal efficiency influenced by particle size, shape, and flow rate, highlighting constructed wetlands as a nature-based option for microplastic mitigation.

2021 The Science of The Total Environment 86 citations
Article Tier 2

Abundance, characteristics, and removal of microplastics in the Cihu Lake-wetland microcosm system

This study evaluated how well a multi-stage constructed wetland system could remove microplastics from wastewater treatment plant effluent, finding a total removal rate of 94.7%. Horizontal subsurface flow wetlands were particularly effective, and physical filtration through the wetland substrate was identified as the dominant removal mechanism. The findings suggest that constructed wetlands are a promising nature-based solution for reducing microplastic discharge into aquatic environments.

2023 Water Science & Technology 9 citations
Article Tier 2

Microplastics occurrence and fate in full-scale treatment wetlands

Researchers assessed microplastic occurrence and fate across full-scale treatment wetlands, finding that constructed wetlands effectively remove a significant proportion of MPs from wastewater but that removal efficiency varies with wetland design and MP characteristics.

2023 Water Research 34 citations
Article Tier 2

Occurrence, fate and removal of microplastics as heavy metal vector in natural wastewater treatment wetland system

Researchers studied microplastic contamination in a natural wastewater treatment wetland system in Eastern India, finding high concentrations in both water and sediments along with toxic heavy metals adsorbed onto the plastic particles. The study found that microplastics acted as vectors for heavy metal contamination in fish and that the treatment ponds removed approximately 53% of surface water microplastics, highlighting the need to account for microplastic pollution in natural wastewater treatment systems.

2021 Water Research 262 citations
Article Tier 2

Effect of microplastics in sludge impacts on the vermicomposting

Researchers examined how adding polyethylene microplastic particles to sludge affects vermicomposting performance. The study found that higher microplastic concentrations reduced the efficiency of organic matter removal, impaired composting quality, and caused oxidative stress and neurotoxicity in earthworms, with bacterial diversity also declining in heavily contaminated treatments.

2021 Bioresource Technology 62 citations
Article Tier 2

Enhancing domestic wastewater treatment: Integrating vermifiltration and biochar for heavy metal and microplastic reduction and by-product utilization

Researchers tested a wastewater treatment system combining earthworms and biochar — a carbon-rich material made by burning organic matter — and found it removed up to 88.6% of microplastics and nearly 100% of several heavy metals from domestic wastewater. The system also produced nutrient-rich organic matter as a byproduct, offering a low-cost, eco-friendly solution for water treatment and soil improvement.

2024 Case Studies in Chemical and Environmental Engineering 14 citations
Article Tier 2

Critical role of benthic fauna in enhancing nanoplastics removal in constructed wetland: Performance, fate and mechanism

Researchers found that adding benthic fauna such as clams and worms to constructed wetlands significantly improved the removal of nanoplastics from wastewater. The organisms enhanced microbial activity and biofilm formation, which helped trap and break down the tiny plastic particles more effectively. The study suggests that incorporating natural organisms into wetland treatment systems could be a practical strategy for addressing nanoplastic pollution.

2024 Journal of Hazardous Materials 15 citations
Article Tier 2

Effect of polystyrene micro/nanoplastics on PCBs removal in constructed wetlands planted with Myriophyllum aquaticum

In constructed wetlands planted with Myriophyllum aquaticum, polystyrene micro- and nanoplastics of varying sizes did not significantly change overall PCB removal rates but altered the dynamics of PCB fate, raising concerns about combined contaminant interactions in wetland treatment systems.

2025 Environmental Research 3 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

Effects of typical sludge treatment on microplastics in China—Characteristics, abundance and micro-morphological evidence

Different sludge treatment technologies used in China including anaerobic digestion, thermal drying, and composting were compared for their effects on microplastic characteristics and abundance, with results showing that treatment method significantly altered microplastic morphology but did not eliminate contamination. The study informs decisions about which treatment approaches best reduce microplastic transfer to soils when sludge is land-applied.

2022 The Science of The Total Environment 45 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

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

Characterization and removal of microplastics in a sewage treatment plant from urban Nagpur, India

Researchers detected microplastics in all stages of a sewage treatment plant in Nagpur, India, finding that the treatment process reduced but did not eliminate microplastics from effluent. Sludge accumulated high concentrations of microplastics, raising concerns about land application of treated sludge.

2022 Environmental Monitoring and Assessment 41 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

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

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