Survival of Escherichia coli in two sewage treatment plants using UV irradiation and chlorination for disinfection

Anastasi, E. M.; Wohlsen, T.; Stratton, Helen; Katouli, Mohammad

doi:10.1016/j.watres.2013.09.008

Cited by 80 publications

(29 citation statements)

References 28 publications

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“…coli biomass entering a WWTP is comprised of these novel, stress-resistant strains and that they persist throughout the treatment stream (i.e., even after chlorine or UV treatment). It was previously reported by Anastasi and colleagues (76) that within the raw sewage influent, only a portion of the E. coli population survives the treatment process when either UV or chlorine is used for disinfection.…”

Section: Discussionmentioning

confidence: 99%

Evidence of Naturalized Stress-Tolerant Strains of Escherichia coli in Municipal Wastewater Treatment Plants

Zhi

Banting

et al. 2016

Appl Environ Microbiol

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Escherichia coli has been proposed to have two habitats—the intestines of mammals/birds and the nonhost environment. Our goal was to assess whether certain strains of E. coli have evolved toward adaptation and survival in wastewater. Raw sewage samples from different treatment plants were subjected to chlorine stress, and ∼59% of the surviving E. coli strains were found to contain a genetic insertion element (IS30) located within the uspC-flhDC intergenic region. The positional location of the IS30 element was not observed across a library of 845 E. coli isolates collected from various animal hosts or within GenBank or whole-genome reference databases for human and animal E. coli isolates (n = 1,177). Phylogenetics clustered the IS30 element-containing wastewater E. coli isolates into a distinct clade, and biomarker analysis revealed that these wastewater isolates contained a single nucleotide polymorphism (SNP) biomarker pattern that was specific for wastewater. These isolates belonged to phylogroup A, possessed generalized stress response (RpoS) activity, and carried the locus of heat resistance, features likely relevant to nonhost environmental survival. Isolates were screened for 28 virulence genes but carried only the fimH marker. Our data suggest that wastewater contains a naturalized resident population of E. coli. We developed an endpoint PCR targeting the IS30 element within the uspC-flhDC intergenic region, and all raw sewage samples (n = 21) were positive for this marker. Conversely, the prevalence of this marker in E. coli-positive surface and groundwater samples was low (≤5%). This simple PCR assay may represent a convenient microbial source-tracking tool for identification of water samples affected by municipal wastewater.IMPORTANCE The results of this study demonstrate that some strains of E. coli appear to have evolved to become naturalized populations in the wastewater environment and possess a number of stress-related genetic elements likely important for survival in this nonhost environment. The presence of non-host-adapted strains in wastewater challenges our understanding of using E. coli as a microbial indicator of wastewater treatment performance, suggesting that the E. coli strains present in human and animal feces may be very different from those found in treated wastewater.

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Section: Discussionmentioning

confidence: 99%

Evidence of Naturalized Stress-Tolerant Strains of Escherichia coli in Municipal Wastewater Treatment Plants

Zhi

Banting

et al. 2016

Appl Environ Microbiol

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“…It also, requires special operation, and potentially forms bromate as a by-product in waters containing bromide [9,10]. Chlorine is a potent oxidant which causes the destruction of nucleic acids and cell membranes and it is an attractive option for disinfection due to its ease of handling, low capital cost and production of residual chlorine [11,12]. However, limitations in the use of chlorine include the production of off-tastes and odours, and potential formation of disinfection by-products (DBPs) such as trihalomethanes (THMs), Haloactic acids (HAAs), Haloacetylnitrile (HAN) and nitrosodimethylamine (NDMA) [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Chlorine Tolerance and Inactivation of Escherichia coli recovered from Wastewater Treatment Plants in the Eastern Cape, South Africa

2017

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Featured Application: This study examined the tolerance of Escherichia coli isolates, a fecal indicator of water contamination, to chlorine as a common water disinfectant and the effectiveness of chlorine at different concentrations in eliminating E. coli in wastewater effluent. Data obtained can be used as baseline monitoring data for future epidemiological surveillances that could further enhance the control of E. coli and some bacteria species of public health concern in wastewater treatment plants and ensure protection of public and environmental health.Abstract: This study investigated the survival of Escherichia coli (E. coli) recovered from secondary effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, in the presence of different chlorine concentrations. The bacterial survival, chlorine lethal dose and inactivation kinetics at lethal doses were examined. The bacterial isolates were identified by 16S rRNA gene sequencing. Comparison of the nucleotide sequences of 16S rRNA gene of bacteria with known taxa in the GenBank revealed the bacterial isolates to belong to Escherichia coli. At the recommended free chlorine of 0.5 mg/L, reduction of E. coli isolates (n = 20) initial bacterial concentration of 8.35-8.75 log was within a range of 3.88-6.0 log at chlorine residuals of 0.14-0.44 mg/L after 30 min. At higher doses, a marked reduction (p < 0.05) in the viability of E. coli isolates was achieved with a greater than 7.3 log inactivation of the bacterial population. Inactivation kinetics revealed a high rate of bacterial kill over time (R 2 > 0.9) at chlorine dose of 1.5 mg/L. This study indicates poor removal of bacteria at free chlorine at 0.5 mg/L and a greater efficacy of 1.5 mg/L in checking E. coli tolerance.

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“…[6][7][8] Consequently, a number of physicochemical disinfection processes have been studied as alternatives to chlorination. [6][7][8] Consequently, a number of physicochemical disinfection processes have been studied as alternatives to chlorination.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of novel, cationic electrospun microfibrous membranes as adsorbents in bacteria removal

et al. 2015

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Electrospun microfibrous membranes comprised of poly(methyl methacrylate)-poly((2diethylaminoethyl) methacrylate) random copolymers (PMMA-co-PDEAEMA) of various chemical compositions blended together with a commercially available PMMA have been fabricated with diameters between 4.0-6.4 µm and further evaluated as adsorbents for bacteria removal from aqueous media. The morphology and thermal stability of the membranes were determined by scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA), respectively. Tensile tests were also performed in order to investigate their mechanical properties. Membrane evaluation as adsorbents against two gram-negative bacteria namely Pseudomonas aeruginosa and Advenella species revealed that the membranes containing the highest percentage of the cationic moieties (DEAEMA) exhibited the highest adsorption efficiency. The bacteria removal by the microfibrous membranes was studied by UV-vis spectrophotometry upon measuring the optical density (OD) of the microorganisms. The highest recorded bacteria removal percentages after 8 hr were approximately 70% and 45%, for the Pseudomonas aeruginosa and Advenella species respectively, whereas in both cases complete (100%) bacteria removal was observed after 24 hr of membrane immersion in bacteria-containing aqueous solutions. The experimental adsorption isotherms for P. aeruginosa and Advenella sp. were well-fitted with the Langmuir isotherm model indicating a monolayer adsorption process. SEM was also used to confirm the adhesion of the bacteria onto the electrospun microfibers. Most importantly, these materials exhibited great performance on the removal of microorganisms from urban wastewater as determined via the standard plating technique prepared by agar. Methyl methacrylate (MMA, Fluka, ≥ 99%), poly(methyl methacrylate) (PMMA) (Mw ∼ 350 000, Sigma-Aldrich), n-hexane (Scharlau, 96%), tetrahydrofuran (THF, Scharlau, extra pure) and ethyl acetate (EA, Scharlau, GC grade, 99.8%) were used without further purification. 2-(diethylaminoethyl) methacrylate (DEAEMA, Sigma-Aldrich, 99%) was passed through a basic alumina column prior to the polymerizations and used without further purification. The radical initiator 2,2'-azobis(2-methylpropionitrile) (AIBN, Sigma-Aldrich, 95%) was recrystallized twice from ethanol. Deuterated chloroform (CDCl 3 , Merck), glutaraldehyde (Sigma-aldrich, 25% in water), calcium chloride dihydrate (CaCl 2 .2H 2 O, Scharlau, Reagent grade), ammonium sulfate ((NH 4 ) 2 SO 4 , Scharlau, reagent grade), sucrose (Himedia), potassium phosphate dibasic (K 2 HPO 4 , Sigma-aldrich, ≥98%), magnesium chloride (MgCl 2 , Sigma, ≥98%) and sodium chloride (NaCl, Himedia) were used as received by the manufacturer. The selected gram-negative microorganisms Pseudomonas aeruginosa LVD-10 and Advenella species LVX-4 were provided by the Applied Microbiology Laboratory culture collection of the Cyprus University of Technology. They were previously isolated and deposited in GenBank with accession number KF728673.1 for P. ...

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Survival of Escherichia coli in two sewage treatment plants using UV irradiation and chlorination for disinfection

Cited by 80 publications

References 28 publications

Evidence of Naturalized Stress-Tolerant Strains of Escherichia coli in Municipal Wastewater Treatment Plants

Evidence of Naturalized Stress-Tolerant Strains of Escherichia coli in Municipal Wastewater Treatment Plants

Chlorine Tolerance and Inactivation of Escherichia coli recovered from Wastewater Treatment Plants in the Eastern Cape, South Africa

Evaluation of novel, cationic electrospun microfibrous membranes as adsorbents in bacteria removal

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