Total coliform and Escherichia coli in microplastic biofilms grown in wastewater and inactivation by peracetic acid

Abstract

Microplastics (MP) have been proposed as a vector for pathogenic microorganisms in the freshwater environment. The objectives of this study were (a) to compare the fecal indicator growth in biofilms on MP and material control microparticles incubated in different wastewater fractions and (b) to compare MP biofilm, natural microparticle biofilm, and planktonic cell susceptibility to disinfection by peracetic acid (PAA). Biofilms were grown on high‐density polyethylene, low‐density polyethylene, polypropylene MP, or wood chips (as a material control) and incubated in either wastewater influent or pre‐disinfection secondary effluent. Reactors were disinfected with PAA, biofilms were dislodged, and total coliform and Escherichia coli were cultivated. Fecal indicators were quantifiable in both MP and wood biofilms incubated in the wastewater influent but only on the wood biofilms incubated in secondary wastewater effluent. More total coliform grew in the wood biofilms than MP biofilms, and the biofilms grown on MP and woodchips were more resistant to disinfection than planktonic bacteria. Thus, it may be possible to refer to the disinfection literature for fecal indicators in biofilm on other particles to predict behavior on MP. Treatments that remove particles in general would help reduce the potential for fecal indicator bypass of disinfection. Practitioner points MP biofilm had lower concentrations of fecal indicators than wood biofilm Biofilm on MP was not more resistant to disinfection than wood biofilm Biofilms, regardless of substrate, were more resistant to disinfection than planktonic organisms

Occurrence of Coliforms in Microplastic Associated Biofilm in Estuarine Ecosystem

“…The findings of present study are in accordance with the findings of Zhang et al [62] explaining that season and location are the key factors determining biofilm formation. Boni et al [63] suggested the presence of coliforms in biofilms in aquatic environment. Further, salinity is a key factor responsible for biofilm formation.…”

Investigations on the co-occurrence of microplastics and other pollutants in the River Yamuna, Delhi

“…As per BIS and WHO standards, fecal coliform bacteria should be completely absent in a drinking water source. Analysis of fecal indicator bacteria (FIB) is a globally adopted parameter for microbial pollution evaluation (Boni et al 2021). High levels of fecal coliforms indicate the presence of pathogenic organisms which might have entered freshwater systems due to sewage discharges, fecal contaminations, or run-off.…”

“…(Murphy et al 2020). Such pathogenic Water Supply Vol 00 No 0, 8 biofilm based-MPs might escape the conventional disinfection process in wastewater treatment plants and increase their viability and reach in the environment (Boni et al 2021). Apart from this, it has also been reported that biofilm based-MPs could act as vectors for the transport of toxic pollutants like heavy metals in different environmental matrices and are a more attractive substrate of choice in comparison to virgin MPs (Xiang et al 2022).…”

The Dangerous Transporters: Study of Microplastic-Associated Bacteria Passing Through Municipal Wastewater Treatment

“…Few studies have evaluated the role of wastewater-derived MPs as transporters of harmful or pathogenic microbiota to the aquatic environment and how wastewater treatments, particularly disinfection, may modify the bacterial community in the plastisphere. Boni et al, 2021 andShen et al (2021) showed in their laboratory studies how MPs can act as a protective habitat for pathogenic bacteria in wastewater, allowing them to survive disinfection treatments (UV, chlorine disinfection, and disinfection by peracetic acid), which is usually effective for free-living bacteria. A recent study of MP biofilms at two different WWTPs demonstrated an increase in bacterial species richness and an abundance of taxa during the wastewater treatment processes, suggesting that WWTPs can have a significant role in modifying the plastisphere (Kelly et al, 2021).…”