scholarly journals Virulence and plasmidic resistance determinants of Escherichia coli isolated from municipal and hospital wastewater treatment plants

2014 ◽  
Vol 13 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Vera Calhau ◽  
Catarina Mendes ◽  
Angelina Pena ◽  
Nuno Mendonça ◽  
Gabriela Jorge Da Silva
Keyword(s):  
Escherichia Coli ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Hospital Wastewater ◽  
Aminoglycoside Resistance ◽  
E Coli

Escherichia coli is simultaneously an indicator of water contamination and a human pathogen. This study aimed to characterize the virulence and resistance of E. coli from municipal and hospital wastewater treatment plants (WWTPs) in central Portugal. From a total of 193 isolates showing reduced susceptibility to cefotaxime and/or nalidixic acid, 20 E. coli with genetically distinct fingerprint profiles were selected and characterized. Resistance to antimicrobials was determined using the disc diffusion method. Extended spectrum β-lactamase and plasmid-mediated quinolone resistance genes, phylogroups, pathogenicity islands (PAIs) and virulence genes were screened by polymerase chain reaction (PCR). CTX-M producers were typed by multilocus sequence typing. Resistance to beta-lactams was associated with the presence of blaTEM,blaSHV, blaCTX-M-15 and blaCTX-M-32. Plasmid-mediated quinolone resistance was associated with qnrA, qnrS and aac(6′)-Ib-cr. Aminoglycoside resistance and multidrug-resistant phenotypes were also detected. PAI IV536, PAI IICFT073, PAI II536 and PAI ICFT073, and uropathogenic genes iutA, papAH and sfa/foc were detected. With regard to the clinical ST131 clone, it carried blaCTX-M-15, blaTEM-type, qnrS and aac(6′)-lb-cr; IncF and IncP plasmids, and virulence factors PAI IV536, PAI ICFT073, PAI IICFT073, iutA, sfa/foc and papAH were identified in the effluent of a hospital plant. WWTPs contribute to the dissemination of virulent and resistant bacteria in water ecosystems, constituting an environmental and public health risk.

scholarly journals Surveillance of antimicrobial-resistant Escherichia coli in Sheltered dogs in the Kanto Region of Japan

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Akihisa Hata ◽  
Noboru Fujitani ◽  
Fumiko Ono ◽  
Yasuhiro Yoshikawa
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Resistant Bacteria ◽  
Animal Shelters ◽  
E Coli ◽  
Chiba Prefecture ◽  
Shelter Dogs ◽  
Kanagawa Prefecture ◽  
Kanto Region

AbstractThere is a lack of an established antimicrobial resistance (AMR) surveillance system in animal welfare centers. Therefore, the AMR prevalence in shelter dogs is rarely known. Herein, we conducted a survey in animal shelters in Chiba and Kanagawa prefectures, in the Kanto Region, Japan, to ascertain the AMR status of Escherichia coli  (E. coli) prevalent in shelter dogs. E. coli was detected in the fecal samples of all 61 and 77 shelter dogs tested in Chiba and Kanagawa, respectively. The AMR was tested against 20 antibiotics. E. coli isolates derived from 16.4% and 26.0% of samples from Chiba and Kanagawa exhibited resistance to at least one antibiotic, respectively. E. coli in samples from Chiba and Kanagawa prefectures were commonly resistant to ampicillin, piperacillin, streptomycin, kanamycin, tetracycline, and nalidixic acid; that from the Kanagawa Prefecture to cefazolin, cefotaxime, aztreonam, ciprofloxacin, and levofloxacin and that from Chiba Prefecture to chloramphenicol and imipenem. Multidrug-resistant bacteria were detected in 18 dogs from both regions; β-lactamase genes (blaTEM, blaDHA-1, blaCTX-M-9 group CTX-M-14), quinolone-resistance protein genes (qnrB and qnrS), and mutations in quinolone-resistance-determining regions (gyrA and parC) were detected. These results could partially represent the AMR data in shelter dogs in the Kanto Region of Japan.

scholarly journals ESKAPE Bacteria and Extended-Spectrum-β-Lactamase-Producing Escherichia coli Isolated from Wastewater and Process Water from German Poultry Slaughterhouses

2020 ◽  
Vol 86 (8) ◽  
Author(s):  
Mykhailo Savin ◽  
Gabriele Bierbaum ◽  
Jens Andre Hammerl ◽  
Céline Heinemann ◽  
Marijo Parcina ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Wastewater Treatment ◽  
Resistance Genes ◽  
Wastewater Treatment Plants ◽  
Process Water ◽  
Resistant Bacteria ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Clinically Relevant Bacteria

ABSTRACT The wastewater of livestock slaughterhouses is considered a source of antimicrobial-resistant bacteria with clinical relevance and may thus be important for their dissemination into the environment. To get an overview of their occurrence and characteristics, we investigated process water (n = 50) from delivery and unclean areas as well as wastewater (n = 32) from the in-house wastewater treatment plants (WWTPs) of two German poultry slaughterhouses (slaughterhouses S1 and S2). The samples were screened for ESKAPE bacteria (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) and Escherichia coli. Their antimicrobial resistance phenotypes and the presence of extended-spectrum-β-lactamase (ESBL), carbapenemase, and mobilizable colistin resistance genes were determined. Selected ESKAPE bacteria were epidemiologically classified using different molecular typing techniques. At least one of the target species was detected in 87.5% (n = 28/32) of the wastewater samples and 86.0% (n = 43/50) of the process water samples. The vast majority of the recovered isolates (94.9%, n = 448/472) was represented by E. coli (39.4%), the A. calcoaceticus-A. baumannii (ACB) complex (32.4%), S. aureus (12.3%), and K. pneumoniae (10.8%), which were widely distributed in the delivery and unclean areas of the individual slaughterhouses, including their wastewater effluents. Enterobacter spp., Enterococcus spp., and P. aeruginosa were less abundant and made up 5.1% of the isolates. Phenotypic and genotypic analyses revealed that the recovered isolates exhibited diverse resistance phenotypes and β-lactamase genes. In conclusion, wastewater effluents from the investigated poultry slaughterhouses exhibited clinically relevant bacteria (E. coli, methicillin-resistant S. aureus, K. pneumoniae, and species of the ACB and Enterobacter cloacae complexes) that contribute to the dissemination of clinically relevant resistances (i.e., blaCTX-M or blaSHV and mcr-1) in the environment. IMPORTANCE Bacteria from livestock may be opportunistic pathogens and carriers of clinically relevant resistance genes, as many antimicrobials are used in both veterinary and human medicine. They may be released into the environment from wastewater treatment plants (WWTPs), which are influenced by wastewater from slaughterhouses, thereby endangering public health. Moreover, process water that accumulates during the slaughtering of poultry is an important reservoir for livestock-associated multidrug-resistant bacteria and may serve as a vector of transmission to occupationally exposed slaughterhouse employees. Mitigation solutions aimed at the reduction of the bacterial discharge into the production water circuit as well as interventions against their further transmission and dissemination need to be elaborated. Furthermore, the efficacy of in-house WWTPs needs to be questioned. Reliable data on the occurrence and diversity of clinically relevant bacteria within the slaughtering production chain and in the WWTP effluents in Germany will help to assess their impact on public and environmental health.

scholarly journals Antibiotic Resistance among Escherichia coli Isolates from Hospital Wastewater Compared to Community Wastewater

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3449
Author(s):  
Cristina-Mirabela Gaşpar ◽  
Ludovic Toma Cziszter ◽  
Cristian Florin Lăzărescu ◽  
Ioan Ţibru ◽  
Marius Pentea ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Hospital Wastewater ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli

This study aimed to compare the antibiotic resistance levels of the indicator bacteria Escherichia coli in wastewater samples collected from two hospitals and two urban communities. Antimicrobial susceptibility testing was performed on 81 E. coli isolates (47 from hospitals and 34 from communities) using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) methodology. Ten antibiotics from nine different classes were chosen. The strains isolated from the community wastewater, compared to those from the hospital wastewater, were not resistant to gentamicin (p = 0.03), but they showed a significantly higher susceptibility—increased exposure to ceftazidime (p = 0.001). Multidrug resistance was observed in 85.11% of the hospital wastewater isolates and 73.53% of the community isolates (p > 0.05). The frequency of the presumed carbapenemase-producing E. coli was higher among the community isolates (76.47% compared to 68.09%) (p > 0.05), whereas the frequency of the presumed extended-spectrum beta-lactamase (ESBL)-producing E. coli was higher among the hospital isolates (21.28% compared to 5.88%) (p > 0.05). The antibiotic resistance rates were high in both the hospital and community wastewaters, with very few significant differences between them, so the community outlet might be a source of resistant bacteria that is at least as important as the well-recognised hospitals.

scholarly journals Prevalence and Mechanism of Fluoroquinolone Resistance in Escherichia coli Isolated from Swine Feces in Korea

2017 ◽  
Vol 80 (7) ◽  
pp. 1145-1151 ◽  
Author(s):  
Yoon Sung Hu ◽  
Sook Shin ◽  
Yong Ho Park ◽  
Kun Taek Park
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Resistance Mechanisms ◽  
Quinolone Resistance ◽  
Feed Additive ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Double Mutation ◽  
Fecal Samples ◽  
E Coli

ABSTRACT In this study, we investigated the prevalence and fluoroquinolone (FQ) resistance mechanisms in Escherichia coli isolated from swine fecal samples. E. coli isolates were collected from 171 (72.2%) of 237 swine fecal samples. Of these, 59 isolates (34.5%) were confirmed as FQ-resistant E. coli by the disk diffusion method. Of the FQ-resistant isolates, three major FQ resistance mechanisms were investigated. Of the 59 isolates, plasmid-mediated quinolone resistance genes were detected in 9 isolates (15.3%). Efflux pump activity was found in 56 isolates (94.9%); however, this was not correlated with the increased FQ resistance measured by determining the MIC. Point mutations in quinolone resistance–determining regions were the main cause of FQ resistance. All 59 ciprofloxacin-resistant isolates had mutations in quinolone resistance–determining regions; of these 59 isolates, all (100%) had mutations in gyrA, 58 (98.3%) had mutations in parC, 22 (37.3%) had mutations in parE, and none had mutations in gyrB. The predominant mutation type was double mutation in gyrA (Ser83Leu plus mutation in aspartic acid 87), and all FQ-resistant isolates (except one) that had mutations in parC or parE also had double mutations in gyrA. Importantly, the frequencies of multidrug-resistant and extended-spectrum β-lactamase–producing E. coli were significantly higher in the high ciprofloxacin MIC group in this study. Compared with previous studies in Korea, the prevalence of FQ resistance and plasmid-mediated quinolone resistance genes had increased considerably in swine. Although the use of FQ as a feed additive is prohibited in Korea, use for self-treatment and therapeutic purposes has been increasing, which may be responsible for the higher FQ resistance rate observed in this study. Therefore, prudent use of FQ on animal farms is warranted to reduce the evolution of FQ-resistant bacteria in the animal industry.

scholarly journals Antibiotic resistance and prevalence of class 1 and 2 integrons in Escherichia coli isolated from hospital wastewater

2018 ◽  
Vol 37 (3) ◽  
pp. 209 ◽  
Author(s):  
Reza Ranjbar ◽  
Maryam Zeynali ◽  
Nooshin Sohrabi ◽  
Asghar Ali Kamboh
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Hospital Wastewater ◽  
Isolation And Identification ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Class 1 ◽  
Hospital Wastewaters

BACKGROUND <br />Hospital wastewaters may contain antibiotic resistant bacteria such as Escherichia coli. These E. coli harbor integron genes that are responsible for antibiotic resistance. The purpose of the current study was to evaluate the frequency of class 1 and 2 integrons in environmental antibiotic resistant E. coli strains isolated from the hospital wastewaters in Tehran, Iran.<br /><br />METHODS<br />As a descriptive cross-sectional study, this research was performed from April to September 2015 on hospital wastewaters in Tehran. Bacterial isolation and identification was performed by standard biochemical and bacteriological procedures. Susceptibility testing was done by employing the disk diffusion method using different antibiotics. Total DNAs were extracted to evaluate the presence of class 1 and 2 integrons by using the polymerase chain reaction (PCR) method with specific primers. <br /><br />RESULTS<br />Fifty E. coli strains were isolated and identified from the wastewaters of 25 hospitals in Tehran. The phenotype results showed that 46 isolates (92%) were resistant to at least one antibiotic and 27 isolates (54%) were multidrug resistant. PCR showed that 35 (70%) and 20 (40%) of the isolates had class 1 and 2 integrons respectively and 14 isolates (28%) had both class 1 and class 2 integrons.<br /><br />CONCLUSION<br />This study has shown a considerable presence of class 1 and class 2 integrons in E. coli strains isolated from hospital wastewaters in Tehran. Proper antibiotics prescription and appropriate hospital wastewater treatment can prevent resistance genes in E. coli from circulating in the environment.

scholarly journals High Carriage of Plasmid-Mediated Quinolone Resistance (PMQR) Genes by Cefotaxime-Resistant Escherichia Coli Recovered from Surface-Leaking Sanitary Sewers

2021 ◽  
Author(s):  
Abimbola Olumide Adekanmbi ◽  
Olabisi C. Akinlabi ◽  
Adedolapo V. Olaposi
Keyword(s):  
Escherichia Coli ◽  
Brain Heart Infusion ◽  
Quinolone Resistance ◽  
Health Concern ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
E Coli ◽  
Specific Pcr ◽  
Sanitary Sewers ◽  
High Level

Abstract There is a rapid rise in the incident of quinolone resistant bacteria in Nigeria. Most studies in Nigeria have focused on isolates from the clinical settings, with few focusing on isolates of environmental origin. This study aimed to investigate the antibiogram and carriage of plasmid-mediated quinolone resistance (PMQR) genes by quinolone-resistant isolates obtained from a pool of cefotaxime-resistant Escherichia coli (E. coli) recovered from sewage leaking out of some broken sanitary sewers in a University community in Nigeria. Isolation of E. coli from the sewage samples was done on CHROMagar E. coli after enrichment of the samples was done in Brain Heart Infusion amended with 6µg/mL of cefotaxime. Identification of presumptive E. coli was done using molecular methods (detection of uidA gene), while susceptibility to antibiotics was carried out using disc-diffusion method. Detection of PMQR genes (qnrA, qnrB, qnrS, aac(6')-lb-cr, qepA and oqxAB) was done using primer-specific PCR. A total of 32 non-repetitive cefotaxime-resistant E. coli were obtained from the sewage, with 21 being quinolone-resistant. The quinolone-resistant isolates showed varying level of resistance to the tested antibiotics, with imipenem being the only exception with 0% resistance. The PMQR genes: aac(6')-lb-cr, qnrA, qnrB, qnrS and qepA and oqxAB were detected in 90.5%, 61.9%, 47.6%, 38.1%, 4.8% and 0% respectively of the isolates. The findings of this study showed a high level of resistance to antibiotics and carriage of PMQR genes by quinolone-resistant E. coli obtained from the leaking sanitary sewers, suggesting a potential environmental and public health concern.

scholarly journals Multidrug-resistant Escherichia coli and Salmonella spp. isolated from pigeons

2020 ◽  
Vol 13 (10) ◽  
pp. 2156-2165
Author(s):  
Shah Jungy Ibna Karim ◽  
Mahfuzul Islam ◽  
Tahmina Sikder ◽  
Rubaya Rubaya ◽  
Joyanta Halder ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nalidixic Acid ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Biochemical Tests ◽  
Salmonella Spp ◽  
Disk Diffusion Method ◽  
Significant Positive Association ◽  
E Coli

Background and Aim: Pigeon rearing has been gaining popularity for recent years. They are reared remarkably very close to the house of the owner. This activity, therefore, may pose potential threats for humans as well as other animals as pigeons may carry and spread different pathogens including drug-resistant bacteria. This study was conducted to explore the prevalence of Escherichia coli and Salmonella spp. as well as their antibiogram profile along with an association analysis. Materials and Methods: Forty swab samples were collected from 20 pigeons during the study. E. coli and Salmonella spp. were isolated and identified on various types of agars, including MacConkey, Eosin methylene blue, Brilliant green, and Salmonella-Shigella agar. Biochemical tests such as the carbohydrate fermentation test, the triple sugar iron agar slant reaction, the indole test, the methyl red test, the catalase test, as well as the Voges–Proskauer test were also performed. Besides, the presence of E. coli was further confirmed by polymerase chain reaction (PCR). Moreover, antimicrobial susceptibility testing of the isolates was performed against nine antibiotics from seven classes on the Mueller-Hinton agar based on the Kirby–Bauer disk diffusion method. Results: The overall prevalence of E. coli and Salmonella spp. was 52.5 and 27.5%, respectively. The prevalence of the pathogenic E. coli was 61.90%. The antibiogram profile of 21 E. coli as well as 11 Salmonella spp. revealed that all isolates, except one, were resistant to one to six antibiotics. Around 61.90%, 71.43%, 23.81%, 61.90%, 23.81%, 19.05%, and 52.38% of E. coli showed resistance against amoxicillin, ampicillin, azithromycin, erythromycin, nalidixic acid, gentamicin, and tetracycline, respectively. Furthermore, E. coli resistance was not observed in case of ciprofloxacin and levofloxacin. Similarly, around 36.36%, 27.27%, 27.27%, 45.45%, 81.82%, 100%, and 18.18% of the Salmonella spp. showed resistance against amoxicillin, ampicillin, azithromycin, erythromycin, nalidixic acid, tetracycline, and levofloxacin, respectively. However, all Salmonella spp. (100%) were found to show sensitivity against ciprofloxacin and gentamicin. Multidrug-resistant (MDR) E. coli (23.80%) and Salmonella spp. (54.54%) were also isolated. Furthermore, both positive (odds ratio [OR] >1) and negative (OR <1) drug resistance associations, with a higher frequency of positive associations, were found in E. coli. A significant positive association was observed between ampicillin and amoxicillin (OR: 81.67, 95% confidence interval: 2.73-2447.57, p=0.01). Conclusion: Pigeon carrying MDR E. coli and Salmonella spp. may contribute to the transmission and spread of these microorganisms. Therefore, strict hygienic measures should be taken during the farming of pigeons to decrease the potential transmission of E. coli and Salmonella spp. from pigeon to humans as well as other animals. So far, this is the first report of the PCR-based identification of pathogenic E. coli from pigeons in Bangladesh.

scholarly journals In vitro activity of antimicrobial peptide CDP-B11 alone and in combination with colistin against colistin-resistant and multidrug-resistant Escherichia coli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaitlin S. Witherell ◽  
Jason Price ◽  
Ashok D. Bandaranayake ◽  
James Olson ◽  
Douglas R. Call
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptide ◽  
Membrane Integrity ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
E Coli ◽  
Minimal Media

AbstractMultidrug-resistant bacteria are a growing global concern, and with increasingly prevalent resistance to last line antibiotics such as colistin, it is imperative that alternative treatment options are identified. Herein we investigated the mechanism of action of a novel antimicrobial peptide (CDP-B11) and its effectiveness against multidrug-resistant bacteria including Escherichia coli #0346, which harbors multiple antibiotic-resistance genes, including mobilized colistin resistance gene (mcr-1). Bacterial membrane potential and membrane integrity assays, measured by flow cytometry, were used to test membrane disruption. Bacterial growth inhibition assays and time to kill assays measured the effectiveness of CDP-B11 alone and in combination with colistin against E. coli #0346 and other bacteria. Hemolysis assays were used to quantify the hemolytic effects of CDP-B11 alone and in combination with colistin. Findings show CDP-B11 disrupts the outer membrane of E. coli #0346. CDP-B11 with colistin inhibits the growth of E. coli #0346 at ≥ 10× lower colistin concentrations compared to colistin alone in Mueller–Hinton media and M9 media. Growth is significantly inhibited in other clinically relevant strains, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In rich media and minimal media, the drug combination kills bacteria at a lower colistin concentration (1.25 μg/mL) compared to colistin alone (2.5 μg/mL). In minimal media, the combination is bactericidal with killing accelerated by up to 2 h compared to colistin alone. Importantly, no significant red blood hemolysis is evident for CDP-B11 alone or in combination with colistin. The characteristics of CDP-B11 presented here indicate that it can be used as a potential monotherapy or as combination therapy with colistin for the treatment of multidrug-resistant infections, including colistin-resistant infections.

scholarly journals Phenotypic Antimicrobial Susceptibility of Escherichia coli from Raw Meats, Ready-to-Eat Meats, and Their Related Samples in One Health Context

2021 ◽  
Vol 9 (2) ◽  
pp. 326
Author(s):  
Frederick Adzitey ◽  
Nurul Huda ◽  
Amir Husni Mohd Shariff
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Resistance Index ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Disk Diffusion Method ◽  
E Coli ◽  
The Usa ◽  
Raw Meats

Meat is an important food source that can provide a significant amount of protein for human development. The occurrence of bacteria that are resistant to antimicrobials in meat poses a public health risk. This study evaluated the occurrence and antimicrobial resistance of E. coli (Escherichia coli) isolated from raw meats, ready-to-eat (RTE) meats and their related samples in Ghana. E. coli was isolated using the USA-FDA Bacteriological Analytical Manual and phenotypic antimicrobial susceptibility test was performed by the disk diffusion method. Of the 200 examined meats and their related samples, 38% were positive for E. coli. Notably, E. coli was highest in raw beef (80%) and lowest in RTE pork (0%). The 45 E. coli isolates were resistant ≥ 50% to amoxicillin, trimethoprim and tetracycline. They were susceptible to azithromycin (87.1%), chloramphenicol (81.3%), imipenem (74.8%), gentamicin (72.0%) and ciprofloxacin (69.5%). A relatively high intermediate resistance of 33.0% was observed for ceftriaxone. E. coli from raw meats, RTE meats, hands of meat sellers and working tools showed some differences and similarities in their phenotypic antimicrobial resistance patterns. Half (51.1%) of the E. coli isolates exhibited multidrug resistance. The E. coli isolates showed twenty-two different resistant patterns, with a multiple antibiotic resistance index of 0.0 to 0.7. The resistant pattern amoxicillin (A, n = 6 isolates) and amoxicillin-trimethoprim (A-TM, n = 6 isolates) were the most common. This study documents that raw meats, RTE meats and their related samples in Ghana are potential sources of antimicrobial-resistant E. coli and pose a risk for the transfer of resistant bacteria to the food chain, environment and humans.

Removal improvement of bacteria (Escherichia coli and enterococci) in maturation ponds using baffles

2012 ◽  
Vol 65 (4) ◽  
pp. 589-595 ◽  
Author(s):  
A. Ouali ◽  
H. Jupsin ◽  
J. L. Vasel ◽  
L. Marouani ◽  
A. Ghrabi
Keyword(s):  
Escherichia Coli ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
E Coli ◽  
Conventional Activated Sludge ◽  
In Series ◽  
Hydrodynamic Study ◽  
Rhodamine Wt ◽  
Engineering Intervention

Korba wastewater treatment plant is a conventional activated sludge followed by three maturation ponds (MP1, MP2, MP3) in series acting as a tertiary treatment. The first study of wastewater treatment plants showed that the effluent concentration of Escherichia coli and enterococci at the outlet of the (MP3) varies between 103 and 104CFU/100 ml. After the hydrodynamic study conducted by Rhodamine WT which showed short-circuiting in the MP1, two baffles were introduced in the first maturation pond (MP1) to improve the hydrodynamic and the sanitary performances. The second hydraulic study showed that the dispersion number ‘d’ was reduced from 1.45 to 0.43 by this engineering intervention and the Peclet number was raised from 0.69 to 2.32. The hydraulic retention time was increased by 14 h. Because of well-designed baffles, the removal efficiency of E. coli and enterococci was raised between 0.2 and 0.7 log units for the first maturation pond.

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