An antimicrobial polycationic sand filter for water disinfection

2011 ◽  
Vol 63 (9) ◽  
pp. 1997-2003 ◽  
Author(s):  
Annalisa Onnis-Hayden ◽  
Bryan B. Hsu ◽  
Alexander M. Klibanov ◽  
April Z. Gu
Keyword(s):  
Treatment Plant ◽  
Antimicrobial Properties ◽  
Bacterial Count ◽  
Water Disinfection ◽  
Aqueous Sample ◽  
Secondary Effluent ◽  
E Coli ◽  
Log Reduction ◽  
Disinfection Process ◽  
Aqueous Effluent

A new sand filtration water disinfection technology is developed which relies on the antimicrobial properties of hydrophobic polycations (N-hexylated polyethylenimine) covalently attached to the sand's surface. The efficacy of the filter disinfection process was evaluated both with water spiked with E. coli and with real aqueous effluent from a wastewater treatment plant. For the former, over 7-log reduction in bacterial count was achieved. With real environmental wastewater secondary effluent samples, the E. coli concentration reduction declined to under 2 logs. This reduced inactivation efficiency compared to the model aqueous sample is likely due to the particulate or colloidal matter present that diminishes the contact between the immobilized polycation and the suspended bacteria. Preliminary sand washing methods were tested to assess potential ‘regeneration’ approaches. Potential advantages of the proposed approach over conventional disinfection in terms of eliminating harmful by-products and reducing energy consumption are discussed.

scholarly journals Influence of organic matter and carbonate on the secondary urban effluents disinfection by UV/H2O2

2018 ◽  
Author(s):  
Ana Ribeiro Neves ◽  
Renato Falcao Dantas ◽  
Jacqueline A. Malvestiti
Keyword(s):  
Organic Matter ◽  
Pure Water ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Effluent Treatment ◽  
Secondary Effluent ◽  
E Coli ◽  
Start Up ◽  
Disinfection Process

The main objective of this research was to study the influence of organic matter and carbonate on UV/H2O2 disinfection, and also to start up the UV/H2O2 reactor to conduct disinfection experiments and to analyze the amount of bacteria (total coliforms and E. coli) during the treatment. The analyzes were carried out with samples from the secondary effluent treatment plant of Faculdade de Tecnologia da Unicamp, the Águas da Serra sewage treatment plant in the city of Limeira and with pure water. The experiments consisted in the treatment of secondary effluent samples ana verify the performance to disinfect analising bacterias in four different times. The relation between the organic matter of the effluent and the disinfection process was studied making a relationship between the bactaria inactivatin and the COD of the effluent. The start up of the UV/H2O2 reactor was positive and allowed the accomplishment of disinfection experiments and later the analysis of concentration of bacteria. For samples from the Águas da Serra effluent, which presented COD of 79 mg/l, the disinfection was extremely efficient with different concentrations of peroxide and there was no indication of the presence of coliforms from the first 10 minutes of treatment.

Antimicrobial resistance of fecal indicators in disinfected wastewater

2011 ◽  
Vol 64 (12) ◽  
pp. 2352-2361 ◽  
Author(s):  
A. Luczkiewicz ◽  
K. Jankowska ◽  
R. Bray ◽  
E. Kulbat ◽  
B. Quant ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Treatment Plant ◽  
Tetracycline Resistance ◽  
Pilot Scale ◽  
Resistant Bacteria ◽  
Secondary Effluent ◽  
Fecal Indicators ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Operation Conditions

The main objective of the study was to assess the potential of three systems (UV irradiation, ozonation, and micro/ultrafiltration) operated in a pilot scale in removal of antimicrobial-resistant fecal bacteria from secondary effluent of the local wastewater treatment plant (700,000 population equivalent). The effectiveness of the processes was analysed using the removal ratio of fecal indicators (Escherichia coli and Enterococcus spp.). The susceptibility of fecal indicators to antimicrobial agents important in human therapy was examined. Resistance to nitrofurantoin and erythromycin was common among enterococci and followed by resistance to fluoroquinolones and tetracycline. Resistance to high-level aminoglycosides and glycopeptides was also observed. E. coli isolates were most frequently resistant to penicillins and tetracycline. The extended-spectrum beta-lactamase-producing E. coli was detected once, after ozonation. Substantial attention should be paid to the E. coli and enterococci resistant to three or more chemical classes of antimicrobials (MAR), which in general constituted up to 15 and 49% of the tested isolates, respectively. Although the applied methods were effective in elimination of fecal indicators (removal efficiency up to 99.99%), special attention has to be paid to the application of sufficient disinfection and operation conditions to avoid selection of antimicrobial resistant bacteria.

scholarly journals Viability of lactic acid bacteria in different components of Ogi with anti diarrhoeagenic E. coli activities

2019 ◽  
Vol 3 (6) ◽  
pp. 206-213
Author(s):  
Roseline Eleojo Kwasi ◽  
Iyanuoluwa Gladys Aremu ◽  
Qudus Olamide Dosunmu ◽  
Funmilola A. Ayeni
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antimicrobial Properties ◽  
Culture Method ◽  
Antimicrobial Activities ◽  
Drying Methods ◽  
Bacterial Strains ◽  
E Coli ◽  
Log Reduction ◽  
Freeze Dried

Background: Ogi constitutes a rich source of lactic acid bacteria (LAB) with associated health benefits to humans through antimicrobial activities. However, the high viability of LAB in Ogi and its supernatant (Omidun) is essential. Aims: This study was carried out to assess the viability of LAB in various forms of modified and natural Ogi and the antimicrobial properties of Omidun against diarrhoeagenic E coli. Methods and Material: The viability of LAB was assessed in fermented Ogi slurry and Omidun for one month and also freeze-dried Ogi with and without added bacterial strains for two months. A further 10 days viability study of modified Omidun, refrigerated Omidun, and normal Ogi was performed. The antimicrobial effects of modified Omidun against five selected strains of diarrhoeagenic E. coli (DEC) were evaluated by the co-culture method. Results: Both drying methods significantly affected carotenoids and phenolic compounds. The Ogi slurry had viable LAB only for 10 days after which, there was a succession of fungi and yeast. Omidun showed 2 log10cfu/ml reduction of LAB count each week and the freeze-dried Ogi showed progressive reduction in viability. Refrigerated Omidun has little viable LAB, while higher viability was seen in modified Omidun (≥2 log cfu/ml) than normal Omidun. Modified Omidun intervention led to 2-4 log reduction in diarrhoeagenic E. coli strains and total inactivation of shigella-toxin producing E. coli H66D strain in co-culture. Conclusions: The consumption of Ogi should be within 10 days of milling using modified Omidun. There are practical potentials of consumption of Omidun in destroying E. coli strains implicated in diarrhea. Keywords: Ogi, Omidun, lactic acid bacteria, diarrhoeagenic Escherichia coli strains, Viability.

Inactivation of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella in Cranberry, Lemon, and Lime Juice Concentrates

2003 ◽  
Vol 66 (9) ◽  
pp. 1637-1641 ◽  
Author(s):  
MARA C. L. NOGUEIRA ◽  
OMAR A. OYARZÁBAL ◽  
DAVID E. GOMBAS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Antimicrobial Properties ◽  
Escherichia Coli O157 ◽  
Bacterial Inactivation ◽  
Lime Juice ◽  
E Coli ◽  
Log Reduction ◽  
C 32

The production of thermally concentrated fruit juices uses temperatures high enough to achieve at least a 5-log reduction of pathogenic bacteria that can occur in raw juice. However, the transportation and storage of concentrates at low temperatures prior to final packaging is a common practice in the juice industry and introduces a potential risk for postconcentration contamination with pathogenic bacteria. The present study was undertaken to evaluate the likelihood of Escherichia coli O157: H7, Listeria monocytogenes and Salmonella surviving in cranberry, lemon, and lime juice concentrates at or above temperatures commonly used for transportation or storage of these concentrates. This study demonstrates that cranberry, lemon, and lime juice concentrates possess intrinsic antimicrobial properties that will eliminate these bacterial pathogens in the event of postconcentration recontamination. Bacterial inactivation was demonstrated under all conditions; at least 5-log Salmonella inactivation was consistently demonstrated at −23°C (−10°F), at least 5-log E. coli O157:H7 inactivation was consistently demonstrated at −11°C (12°F), and at least 5-log L. monocytogenes inactivation was consistently demonstrated at 0°C (32°F).

scholarly journals Preventing maritime transport of pathogens: the remarkable antimicrobial properties of silver-supported catalysts for ship ballast water disinfection

2017 ◽  
Vol 76 (3) ◽  
pp. 712-718 ◽  
Author(s):  
C. P. Theologides ◽  
S. P. Theofilou ◽  
A. Anayiotos ◽  
C. N. Costa
Keyword(s):  
Ballast Water ◽  
Supported Catalysts ◽  
Antimicrobial Properties ◽  
Antimicrobial Treatment ◽  
Water Disinfection ◽  
Shipping Industry ◽  
E Coli ◽  
Ionic Silver ◽  
Short Period ◽  
Ship Ballast Water

Ship ballast water (SBW) antimicrobial treatment is considered as a priority issue for the shipping industry. The present work investigates the possibility of utilizing antimicrobial catalysis as an effective method for the treatment of SBW. Taking into account the well-known antimicrobial properties of ionic silver (Ag+), five silver-supported catalysts (Ag/γ-Al2O3) with various loadings (0.05, 0.1, 0.2, 0.5, and 1 wt%) were prepared and examined for the antimicrobial treatment of SBW. The bactericidal activity of the aforementioned catalysts was investigated towards the inhibition of Escherichia coli (Gram-negative) and Escherichia faecalis (Gram-positive) bacteria. Catalytic experiments were conducted in a three-phase continuous flow stirred tank reactor, used in a semi-batch mode. It was found that using the catalyst with the lowest metal loading, the inhibition of E. coli reached 95.8% after 30 minutes of treatment of an E. coli bacterial solution, while the inhibition obtained for E. faecalis was 76.2% after 60 minutes of treatment of an E. faecalis bacterial solution. Even better results (100% inhibition after 5 min of reaction) were obtained using the catalysts with higher Ag loadings. The results of the present work indicate that the prepared monometallic catalysts exert their antimicrobial activity within a short period of time, revealing, for the first time ever, that the field of antimicrobial heterogeneous catalysis using deposited ionic silver on a solid support may prove decisive for the disinfection of SBW.

scholarly journals Critical Synergistic Concentration of Lecithin Phospholipids Improves the Antimicrobial Activity of Eugenol against Escherichia coli

2017 ◽  
Vol 83 (21) ◽  
Author(s):  
Haoshu Zhang ◽  
Edward G. Dudley ◽  
Federico Harte
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Rational Design ◽  
Microbial Population ◽  
Critical Concentration ◽  
Antimicrobial Properties ◽  
Content Type ◽  
E Coli ◽  
Log Reduction ◽  
Naturally Occurring

ABSTRACT In this study, the effect of individual lecithin phospholipids on the antimicrobial properties of eugenol against Escherichia coli C600 was investigated. We tested five major phospholipids common in soy or egg lecithin (1,2-dihexadecanoyl-sn-glycero-3-phosphocholine [DPPC], 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine [DSPC], 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine [DPPE], 1,2-dihexadecanoyl-sn-glycero-3-phosphate [sodium salt] [DPPA], and 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine [DPPS]) and one synthetic cationic phospholipid (1,2-dioctadecanoyl-sn-glycero-3-ethylphosphocholine [18:0 EPC]). Among the six phospholipids, DPPC, DSPC, DPPE, DPPA, and the cationic 18:0 EPC showed critical synergistic concentrations that significantly improved the inactivation effect of eugenol against E. coli after 30 min of exposure. At the critical synergistic concentration, an additional ca. 0.4 to 1.9 log reduction (ca. 0.66 to 2.17 log CFU/ml reduction) in the microbial population was observed compared to eugenol-only (control) treatments (ca. 0.25 log reduction). In all cases, increasing the phospholipid amount above the critical synergistic concentration (which was different for each phospholipid) resulted in antimicrobial properties similar to those seen with the eugenol-only (control) treatments. DPPS did not affect the antimicrobial properties of eugenol at the tested concentrations. The critical synergistic concentration of phospholipids was correlated with their critical micelle concentrations (CMC). IMPORTANCE Essential oils (EOs) are naturally occurring antimicrobials, with limited use in food due to their hydrophobicity and strong aroma. Lecithin is used as a natural emulsifier to stabilize EOs in aqueous systems. We previously demonstrated that, within a narrow critical-concentration window, lecithin can synergistically enhance the antimicrobial properties of eugenol. Since lecithin is a mixture of different phospholipids, we aimed to identify which phospholipids are crucial for the observed synergistic effect. This research studied the bioactivity of lecithin phospholipids, contributing to a rational design in using lecithin to effectively control foodborne pathogens in foods.

Ozonation of a secondary effluent both for fresh water protection and re-use

2006 ◽  
Vol 1 (2) ◽  
Author(s):  
M. Antonelli ◽  
V. Mezzanotte ◽  
C. Nurizzo
Keyword(s):  
Contact Time ◽  
Pilot Scale ◽  
Secondary Effluent ◽  
Water Protection ◽  
Faecal Coliforms ◽  
Colour Removal ◽  
E Coli ◽  
Log Reduction ◽  
Ionic Compounds ◽  
Higher Doses

49 trials were carried out at pilot scale to evaluate ozonation for polishing a nitrified and filtered effluent discharged in a brook, lying in a recreational protected area whose low and irregular flow provides a negligible dilution. Four ozone doses (3, 5, 7.5 and 10 mg O3/L) were tested and contact time was set at 10 minutes for each of the three contact columns. In most cases, at 3 mg O3/L, residual ozone concentration was below detection limit after 10 minutes contact time. For faecal coliforms and E. coli, log reduction increased from 3 mg O3/L to higher ozone doses, among which no appreciable difference was observed. No improvement in disinfection efficiency was seen for contact times over 10 minutes. Complete disinfection was obtained only in few cases, but final counts complying with the limits for discharge were always met. COD removal was low, while colour removal was significant and clearly increasing from 3 mg O3/L to higher doses. The removal of surfactants slightly increased with increasing dose for non ionic compounds, but not for anionic ones. Data confirmed that slight increases in ozone dose involve the release of bacterial organic matter which partially counterbalance the removal of COD.

scholarly journals Bactericidal activity of Ag nanoparticle-impregnated fibreglass for water disinfection

2009 ◽  
Vol 7 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Gordon Nangmenyi ◽  
Wei Xao ◽  
Sharifeh Mehrabi ◽  
Eric Mintz ◽  
James Economy
Keyword(s):  
Silver Nanoparticles ◽  
Silver Content ◽  
Immersion Test ◽  
Water Disinfection ◽  
X Ray Diffraction ◽  
Thermal Regeneration ◽  
X Ray ◽  
E Coli ◽  
Log Reduction ◽  
Activated Carbon Fibres

A new bactericidal system composed of fibreglass impregnated with silver (Ag) nanoparticles was developed and tested. Silver content, particle size and distribution were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The antibacterial effectiveness was evaluated against Escherichia coli (E. coli, ATCC 29055). The minimum inhibitory loading was determined to be less than 1.8 wt% of silver nanoparticles per gram of fibreglass. In a 1 h immersion test, using a 0.1 mg fibreglass mat ml−1, with 2.9 wt% loading of silver nanoparticles completely disinfected 100 ml of 106 CFU ml−1 of E. coli, dramatically outperforming activated carbon fibres impregnated with silver. Inactivation rate studies of 0.05 mg fibreglass mat ml−1 (Ag 1.8 wt%) with 1012 CFU E. coli displayed a 7 log reduction in 5 minutes. The activation and reuse of fibreglass (Ag 4.3 wt%) maintained its full effectiveness after two cycles of use and thermal regeneration at 350°C.

Advanced Treatment of Municipal Wastewater Effluent by Coagulation/Sedimentation and Chlorine Dioxide Disinfection

2011 ◽  
Vol 71-78 ◽  
pp. 2792-2796
Author(s):  
Li Hua Cheng ◽  
Ai Hua He ◽  
Xue Jun Bi ◽  
Qi Wang
Keyword(s):  
Chlorine Dioxide ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Tertiary Treatment ◽  
Combination Process ◽  
E Coli ◽  
Chlorine Dioxide Disinfection ◽  
Selection Of

Due to increasing water scarcity, reclamation and reuse of the secondary effluent of wastewater treatment plant are widely concerned in many countries. Before reuse, the residual contaminant in the secondary effluent should be further removed to guarantee safe reuse. Coagulation/sedimentation and subsequent chlorine dioxide(ClO2) disinfection was adopted for tertiary treatment of secondary effluent. Selection of coagulant and optimization of tertiary treatment parameters were performed in this study. The results showed that coagulation could remove turbidity and total phosphours(TP) effectively. Polyaluminium chloride(PAC) was the most suitable coagulant. The optimal coagulation condition was as follows: PAC dosage of 10mg/L(measured as Al3+), reaction time of 20 min, settling time of 40 min, in this case, the average removal rate of turbidity, color, UV254, TP and TOC could reach to 58.2%, 22.8%, 18.2%, 60.6% and 22.2%, respectively. ClO2could inactive bacteria andE. colieffectively. ClO2could further remove UV254, color and TOC. In case of ClO2dosage of 5mg/L, the sterilization efficiency could reach 100%, and the removal rate of UV254, color and TOC was higher than 25%, 70% and 25%, respectively. In the optimal condition, the removal efficiency of residual contaminant by the combination process was as follows: UV254of 45.9%, color of 76.5%, TOC of 66.7%, turbidity of 61.9% and TP of 96.3%.

scholarly journals Disinfection of Male Luer Style Connectors for Prevention of Catheter Related Bloodstream Infections Using an Isopropyl Alcohol Dispensing Cap

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
James P. Kennedy ◽  
Richard A. Lasher ◽  
Donald Solomon ◽  
Robert W. Hitchcock
Keyword(s):  
Isopropyl Alcohol ◽  
Bacterial Colonization ◽  
Reaction Force ◽  
Bloodstream Infections ◽  
Bacterial Count ◽  
Positive Control ◽  
Test Apparatus ◽  
Two Phase ◽  
E Coli ◽  
Log Reduction

Bacterial colonization of needleless injection sites (NISs) frequently results in catheter related bloodstream infections (CRBSIs). Hospitals have instituted protocols aimed at disinfecting NIS prior to access. Furthermore, several manufactures have developed devices that facilitate disinfection of NIS. Despite these steps, the incidence of CRBSI is still alarmingly high. Currently, there is no protocol or device intended to disinfect male luer connectors such as those found on IV tubing that are commonly coupled and decoupled from the NISs. Since these IV tubing connectors directly contact the NIS (which have been repeatedly shown to have varying levels of bacterial colonization), it is highly likely that they, too, will have varying levels of contamination. In order for disinfection of the NIS to be effective, the IV tubing connector must also be disinfected. Our design goal was to develop a device that could be used to disinfect a male luer style connector without allowing antiseptic into the inner lumen of the male luer. We designed a three component system that utilizes a silicone sealing cone to seal the male luer, a reservoir foam that holds 70% isopropyl alcohol (IPA), and a reaction force foam that increases the seal pressure of the sealing cone while the reservoir foam is compressed delivering the IPA to the outside surface of the male luer post. Sealing cone geometry was optimized using a custom built seal pressure test apparatus. Reservoir and reaction force foam functional parameters were assessed using an Instron test apparatus. A two phase compression stroke was designed into the device to allow for sealing and dispensing of IPA. An IPA transfer test was used to assess the transfer of disinfectant from the reservoir foam to a liquid filled male luer connector (modeling an IV tubing connector). No disinfectant was found to be transferred from the device to the inner lumen of the IV tubing connector model (n=30). To test the efficacy of the device on reducing bacterial count on the male luer, a disinfection study was performed using the optimized device. Male luers were immersed in bacterial suspensions of S. aureus, S. epidermis, P. aerginosa, and E. coli. A 4 log reduction compared with a positive control was found in each sample treated with our disinfection cap (n=120). In conclusion, we developed a device that effectively delivers an antiseptic to a male luer style connector without leaking any antiseptic to the inner lumen of the luer post

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