Papers

61,005 results
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Article Tier 2

Microplastics affect the ammonia oxidation performance of aerobic granular sludge and enrich the intracellular and extracellular antibiotic resistance genes

Exposure of aerobic granular sludge to PVC, PA, PS, and PE microplastics at 10 mg/L inhibited ammonia oxidation but nitrification recovered over time; all four MP types enriched intracellular and extracellular antibiotic resistance genes and suppressed ammonia-oxidizing bacteria.

2020 Journal of Hazardous Materials 104 citations
Article Tier 2

Impact of polyethylene microplastics on the nitrogen removal and bacterial community in sequencing batch reactor at different hydraulic retention times

Researchers examined how polyethylene microplastics affect nitrogen removal performance in biological wastewater treatment at different hydraulic retention times. The study found that the presence of microplastics amplified the negative effects of shortened treatment times on nitrogen removal efficiency and altered bacterial communities and enzyme levels involved in nitrification and denitrification, offering new insights into how microplastics interfere with wastewater treatment processes.

2025 Journal of Environmental Management 7 citations
Article Tier 2

Exposure to polyamide 66 microplastic leads to effects performance and microbial community structure of aerobic granular sludge

Polyamide 66 microplastics were introduced into aerobic granular sludge bioreactors at varying concentrations, initially reducing contaminant removal efficiency but recovering to near-control levels by the end of the experiment. The study shows that while microplastics transiently disrupt biological wastewater treatment, the microbial community can adapt over time.

2019 Ecotoxicology and Environmental Safety 101 citations
Article Tier 2

Effects of microplastics accumulation on performance of membrane bioreactor for wastewater treatment

Researchers simulated the long-term accumulation of polypropylene microplastics in membrane bioreactors used for wastewater treatment. They found that while microplastic accumulation did not reduce the removal of key pollutants like COD and ammonia nitrogen, it did increase membrane fouling and alter the composition of microbial communities in the reactor. The study suggests that microplastic buildup in wastewater treatment systems may affect operational efficiency over time.

2021 Chemosphere 77 citations
Article Tier 2

Insight into effect of polyethylene microplastic on nitrogen removal in moving bed biofilm reactor: Focusing on microbial community and species interactions

Researchers studied how polyethylene microplastics affect nitrogen removal in wastewater treatment bioreactors and found that low concentrations slightly improved the process, while higher concentrations disrupted it. The microplastics changed the microbial communities responsible for breaking down nitrogen in wastewater. This matters because less effective wastewater treatment means more nitrogen pollution in waterways, and microplastics entering treatment plants could reduce their ability to clean water effectively.

2024 The Science of The Total Environment 17 citations
Article Tier 2

Effect of long-term exposure to non-biodegradable and biodegradable microplastics in continuous anoxic/aerobic bioreactors: Nitrogen removal performance, microbial communities and functional gene responses

Researchers compared the effects of biodegradable and non-biodegradable microplastics on nitrogen removal in wastewater treatment bioreactors over an extended period. They found that biodegradable polylactic acid particles were actually more harmful than conventional PET microplastics, significantly reducing the efficiency of ammonia removal by damaging beneficial bacteria. The study challenges the assumption that biodegradable plastics are always safer for wastewater treatment systems.

2024 Journal of Environmental Management 8 citations
Article Tier 2

Responses of nitrogen removal, microbial community and antibiotic resistance genes to biodegradable microplastics during biological wastewater treatment

Researchers compared the effects of three biodegradable microplastics on nitrogen removal and microbial communities in activated sludge wastewater treatment. They found that PHA and PLA at higher concentrations enhanced denitrification but also promoted antibiotic resistance genes, while PBS had minimal effects. The study suggests that the breakdown of biodegradable plastics into microplastics in wastewater systems may have complex and sometimes counterintuitive effects on treatment performance.

2025 Biochemical Engineering Journal 7 citations
Article Tier 2

Impact and microbial mechanism of continuous nanoplastics exposure on the urban wastewater treatment process

Researchers investigated the effects of continuous nanoplastic exposure on wastewater treatment over 200 days, finding that while total nitrogen removal was not significantly inhibited, nanoplastics altered microbial community composition and affected nitrification and denitrification processes.

2022 Water Research 37 citations
Article Tier 2

The short and long-term effect of polystyrene nanoplastics on nitrifying sludge at high nitrite concentrations

Researchers examined polystyrene nanoplastic effects on nitrifying sludge and found that while short- and long-term exposure had little impact on nitrification performance, long-term exposure shifted the nitrite-oxidizing bacterial community from Nitrobacter to Nitrospira dominance and altered cell metabolism.

2023 Journal of Environmental Sciences 10 citations
Article Tier 2

Long-term effect of polyethylene microplastics on the bioelectrochemical nitrogen removal process

Researchers explored how polyethylene microplastics affect nitrogen removal in bioelectrochemical wastewater treatment systems over long-term exposure. The study found that microplastic exposure reduced nitrogen removal efficiency by decreasing biofilm viability, lowering extracellular polymeric substance content, and significantly shifting the microbial community structure responsible for nitrogen processing.

2023 Chemical Engineering Journal 24 citations
Article Tier 2

Microplastics accelerate nitrification, shape the microbial community, and alter antibiotic resistance during the nitrifying process

Researchers found that adding microplastics to wastewater treatment systems actually sped up nitrification (a key step in processing sewage) but also promoted the growth of antibiotic-resistant bacteria. Even biodegradable PLA plastics, often considered more environmentally friendly, significantly increased antibiotic resistance genes. This study warns that microplastics in wastewater systems could be accelerating the spread of antibiotic resistance, a major public health threat.

2024 The Science of The Total Environment 12 citations
Article Tier 2

Microplastics shaped performance, microbial ecology and community assembly in simultaneous nitrification, denitrification and phosphorus removal process

This study found that polystyrene and PVC microplastics disrupted the performance of wastewater treatment systems designed to remove nitrogen and phosphorus, reducing nitrogen removal by up to 10%. The microplastics altered microbial communities, decreased cooperation between beneficial bacteria, and blocked important biological pathways. Since wastewater treatment is a key barrier against pollution reaching drinking water, microplastic interference with these systems could indirectly increase human exposure to harmful contaminants.

2024 The Science of The Total Environment 12 citations
Article Tier 2

The effects of microplastics and nanoplastics on nitrogen removal, extracellular polymeric substances and microbial community in sequencing batch reactor

Researchers found that polystyrene nanoplastics and microplastics impaired nitrogen removal in sequencing batch reactors by reducing denitrification rates, altering extracellular polymeric substances, and shifting microbial community composition in activated sludge.

2023 Bioresource Technology 54 citations
Article Tier 2

Responses of nitrogen removal under microplastics versus nanoplastics stress in SBR: Toxicity, microbial community and functional genes

Researchers compared the effects of microplastics versus nanoplastics on nitrogen removal in sequencing batch reactors used in wastewater treatment. The study found that microplastics had no significant effect on nitrogen removal, while high concentrations of nanoplastics impaired the process by disrupting microbial communities and functional gene expression. The results suggest that nanoplastics may pose a greater threat to biological wastewater treatment performance than microplastics.

2022 Journal of Hazardous Materials 73 citations
Article Tier 2

Effects of microplastic biofilms on nutrient cycling in simulated freshwater systems

Polypropylene microplastic biofilms in freshwater microcosms accelerated nitrogen cycling processes including ammonia oxidation and denitrification, and temporarily accumulated phosphorus before releasing it as biofilms matured and broke apart. The results demonstrate that microplastic-associated biofilms actively alter nutrient dynamics in freshwater systems, with potential consequences for water quality.

2020 The Science of The Total Environment 207 citations
Article Tier 2

Microplastics provide new niches for nitrifiers to maintain nitrification performance in nitrifying bioreactors

Researchers found that microplastics provide novel niches for nitrifying bacteria in wastewater treatment systems, with MP surfaces maintaining nitrification performance even under stress conditions that suppress conventional nitrifiers, suggesting unexpected ecosystem services from plastic contamination in treatment settings.

2025 Environmental Research
Article Tier 2

Effects of exposure to polyether sulfone microplastic on the nitrifying process and microbial community structure in aerobic granular sludge

Scientists added polyether sulfone microplastics to aerobic granular sludge bioreactors at different concentrations and found only minor effects on ammonia removal but an increase in total nitrogen removal efficiency of 5.6%, along with shifts in nitrifying microbial community structure.

2020 Bioresource Technology 110 citations
Article Tier 2

Influence of nanoplastic type on the short-cut nitrification-denitrification in a sequencing batch reactor: Elucidating the metabolic relationship of nitrogen, extracellular polymeric substances, and oxidative stress

Researchers compared the effects of biodegradable (PBAT) and non-biodegradable (polyethylene) nanoplastics on nitrogen-removing bacteria in a wastewater reactor, finding that both types disrupted nitrogen metabolism, extracellular polymer production, and oxidative stress pathways, with non-biodegradable polyethylene causing more severe inhibition of the treatment process.

2026 Journal of Hazardous Materials
Article Tier 2

Response of wastewater treatment performance and bacterial community to original and aged polyvinyl chloride microplastics in sequencing batch reactors

This study found that PVC microplastics, both fresh and aged, severely harmed wastewater treatment processes by reducing the removal of harmful chemicals like ammonia and organic pollutants. The microplastics shifted the bacterial communities in the treatment system, reducing helpful nitrogen-removing bacteria while promoting other types. This means microplastic contamination of wastewater plants could lead to poorer water treatment quality, allowing more pollutants to reach rivers and drinking water sources.

2025 Bioresource Technology 8 citations
Article Tier 2

Analysis of the Partial Nitrification Process Affected by Polyvinylchloride Microplastics in Treating High-Ammonia Anaerobic Digestates

Researchers found that PVC microplastics at high concentrations inhibited the partial nitrification process used to treat ammonia-rich wastewater from anaerobic digesters. The findings indicate that microplastics accumulating in wastewater treatment systems can interfere with biological nitrogen removal.

2020 ACS Omega 29 citations
Article Tier 2

Insights into N2O turnovers under polyethylene terephthalate microplastics stress in mainstream biological nitrogen removal process

Long-term exposure of biological nitrogen removal (BNR) wastewater systems to polyethylene terephthalate microplastics at concentrations up to 500 micrograms per liter altered nitrous oxide (N2O) production and reduction during denitrification over 100-plus days of treatment. The findings suggest MPs in municipal wastewater could inadvertently increase greenhouse gas emissions from wastewater treatment plants.

2022 Water Research 56 citations
Article Tier 2

Deciphering anammox response characteristics and potential mechanisms to polyethylene terephthalate microplastic exposure

This study tested how PET microplastics affect the bacteria used in wastewater treatment for removing nitrogen pollutants. Long-term exposure to high concentrations of PET microplastics reduced the nitrogen removal efficiency by nearly 29%, though the system partially recovered over three months. The findings matter because compromised wastewater treatment means more pollutants could end up in waterways that supply drinking water.

2024 Journal of Hazardous Materials 11 citations
Article Tier 2

Microplastics perturb nitrogen removal, microbial community and metabolism mechanism in biofilm system

Researchers found that polystyrene and PET microplastics reduced total nitrogen removal by 7-16% in biofilm wastewater treatment systems by causing cell damage, altering microbial community structure, and suppressing key genes involved in denitrification and nitrogen conversion.

2023 Journal of Hazardous Materials 57 citations
Article Tier 2

Unveiling the plastisphere in anammox process: Physicochemical evolution of microplastics and microbial succession dynamics

Researchers tracked how polyethylene terephthalate microplastics change physically and chemically over 30 days in an anaerobic wastewater treatment system. They found that while the microplastics had minimal impact on nitrogen removal efficiency, they developed distinct microbial communities on their surfaces that evolved over time. The study provides new insights into how microplastics interact with beneficial microbes in wastewater treatment processes.

2025 Journal of Hazardous Materials 3 citations