Slightly Acidic Electrolyzed Water to Remove Methylobacterium mesophilicum, Rhodotorula mucilaginosa and Cladosporium cladosporioides in Households (original) (raw)
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Electrochemical Removal of Microorganisms in Drinking Water
It is known that silver, even in small concentrations (hundred parts of milligrams per liter), has the ability to destroy microorganisms, i.e. it has strong bactericidal abilities. Cleansing vast amount of water using bactericidal ability of silver is usually performed in electrochemical way. The advantages of electrochemical disinfection process like: (a) environmental compatibility, (b) versatility to kill a wide variety of microorganisms under mild conditions, (c) no need for adding chemical medicines and (d) the benefits of in-situ generation greatly lower problems and dangers of usage gas chlorine in water disinfection, which is greatest during transport and storing of this disinfectant. Appliances for electrochemical disinfection of drinking water eliminate these faults of conventional disinfection methods. Medical researches show that excess of chlorine in water reacts with organic matter, leading to mutations and cancer formation in digestion organs and bladder. This paper represents research of succesful microbiological disinfection of natural water that contains Acinetobacter, Pseudomonas aeruginisa, Sulfate-reducing clostridium, Streptococcus (F), Aeromonas, Citrobacter (F), Esherichia coli, Enterobacter (F) and Bacillus by water-disinfection appliance. This appliance can be used in water systems like water sorces, traps, reservoires, pools etc. (certificate of Clinical Center of Serbia).
Electrolytic Method for Deactivation of Microbial Pathogens in Surface Water for Domestic Use
Electrochemical or electrolytic disinfection is one of the emerging technologies for treating drinking water and wastewater. This method gained much attention, especially because of its practical feasibility as there is no need for addition of chemicals or generation of toxic byproducts. In addition to this, the operational cost is also low. This work is thus aimed at studying the deactivation of waterborne pathogens from lake water by electrolytic disinfection. The electrolytic disinfection unit (EDU) was designed and examined for efficiency of deactivation of microbial pathogens in raw lake water. The batch scale experiments were performed to investigate the effect of aluminum electrodes with direct current (D.C.) supply on the inactivation efficiency of index microorganisms and pathogens namely Total coliforms, Faecal coliforms, E. coli and Faecal streptococci and pathogens, namely Salmonella spp. and Shigella spp. The optimum current intensity (Ampere (A)) and contact time for 80 to 95 % inactivation of pathogen indicators and pathogens were observed to be (1A 90 minutes) and (2A 90 minutes).
PeerJ, 2020
Bacterial inactivation is a crucial aspect of sanitation and hygiene. The effectiveness of slightly acidic electrolyzed water (SAEW) for reduction or removal of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus epidermidis was evaluated. The bactericidal activity of SAEW and sodium hypochlorite (NaOCl) against E. coli and P. aeruginosa were compared through in vitro experiments. The effectiveness of SAEW spray was tested against S. epidermidis. Results showed that SAEW had a more powerful bactericidal activity than NaOCl at the same available chlorine concentrations. For E. coli, SAEW decreased the bacterial counts from 8.4 log10 CFU/mL to less than 3.9 log10 CFU/mL; NaOCl with the same available chlorine of 0.5 mg/L, caused a decrease from 8.4 log10 CFU/mL to 7.1 log10 CFU/mL. For P. aeruginosa, SAEW caused bacterial counts to decrease from 8.5 log10 CFU/mL to less than 4.1 log10 CFU/mL against 8.5 log10 CFU/mL to 6.2 log10 CFU/mL for NaOCl with the same available chlorin...
Water Science & Technology: Water Supply, 2014
Drinking water disinfection techniques without the dosage of chemicals are regarded as more advantageous in terms of costs and practical use. Here we investigated the efficacy of electrochemical disinfection for inactivation of Bacillus subtilis sporesa model microorganism of highly resistant pathogens. The effect of electrochemical disinfection with Ti n O 2nÀ1 ceramic electrodes which generate active chlorine from chloride in situ, was compared to the traditional chlorination in which active chlorine was produced from addition of sodium hypochlorite. Research was performed on a batch scale with a synthetic buffered drinking water containing 35.5 mg/l of chloride ions. Spore viability was analysed with both cultivation and cell potential for dividing (direct viable count method). The results showed that at similar residual disinfectant concentrations x contact time (CT value), electrochemical disinfection was over three times more effective in neutralizing both cultivable B. subtilis spores and those with cell potential for dividing than traditional chlorination. As in chlorination, electrochemical disinfection was shown to be water-pH dependent and the lowest CT value of 112 mg/l min À1 (2-log removal) was obtained at pH 6. The lowest efficiency for both techniques was observed at pH 8. In conclusion, electrochemical disinfection is a viable in situ method even at low levels of chlorides in drinking water and appears to be more effective than simple chlorination with the addition of the active chlorine species when highly resistant microbial forms are analysed, however, to apply the technology on a large scale additional studies on potential formation of disinfection by-products must be performed.
Inactivation of E. coli, Legionella, and Pseudomonas in Tap Water Using Electrochemical Disinfection
Disinfection of hot water systems is critical in reducing the incidence of disease outbreaks caused by pathogenic bacteria. Electrochemical disinfection (ED) has been identified as an economical, low-maintenance, and chemical-free alternative in the fight against waterborne pathogenic microorganisms. It also provides the residual disinfection needed to inactivate the planktonic bacteria released by the biofilm. The work presented here includes fundamental small-scale laboratory optimization experiments in a flask where platinum-coated electrodes were immersed in 3.5 L of tap water contaminated with Escherichia coli (NCT10418) with an initial population density between 3 × 10 5 and 1.6 × 10 5 colony forming units=mL (CFU=mL) or Legionella pneumophila serogroup 1 (NCTC12821) ranging from 180 to 244 CFU=mL. Voltage, electrode area, interelectrode distance, spiking time, volume of contaminated water, and mixer speed were varied to determine the optimal geometrical and operational requirements needed to kill bacteria. Experimental results indicate ED to be an effective control method, with a >4-log inactivation of E. coli and a >5-log inactivation of Legionella in 10 and 45 min, respectively, at a current density of ≈4 mA=cm 2. The findings of the flask experiments were translated into real-world conditions by evaluating the long-term performance of an optimized ED prototype device installed in the hot water recirculation system of a small-size healthcare center building. The results showed that ED is effective at minimizing pathogen contamination of the hot water distribution system from initial values, with total bacteria levels and Pseudomonas species being reduced in all of the samples over a 15-month period following activation of the ED device.
Journal of Environmental Engineering, 2016
Disinfection of hot water systems is critical in reducing the incidence of disease outbreaks caused by pathogenic bacteria. Electrochemical disinfection (ED) has been identified as an economical, low-maintenance, and chemical-free alternative in the fight against waterborne pathogenic microorganisms. It also provides the residual disinfection needed to inactivate the planktonic bacteria released by the biofilm. The work presented here includes fundamental small-scale laboratory optimization experiments in a flask where platinum-coated electrodes were immersed in 3.5 L of tap water contaminated with Escherichia coli (NCT10418) with an initial population density between 3 × 10 5 and 1.6 × 10 5 colony forming units=mL (CFU=mL) or Legionella pneumophila serogroup 1 (NCTC12821) ranging from 180 to 244 CFU=mL. Voltage, electrode area, interelectrode distance, spiking time, volume of contaminated water, and mixer speed were varied to determine the optimal geometrical and operational requirements needed to kill bacteria. Experimental results indicate ED to be an effective control method, with a >4-log inactivation of E. coli and a >5-log inactivation of Legionella in 10 and 45 min, respectively, at a current density of ≈4 mA=cm 2. The findings of the flask experiments were translated into real-world conditions by evaluating the long-term performance of an optimized ED prototype device installed in the hot water recirculation system of a small-size healthcare center building. The results showed that ED is effective at minimizing pathogen contamination of the hot water distribution system from initial values, with total bacteria levels and Pseudomonas species being reduced in all of the samples over a 15-month period following activation of the ED device.
Drinking Water Disinfection with Electrolysis
Latvian Journal of Chemistry, 2012
Nowadays electrochemical disinfection has gained an increasing attention as an alternative to conventional drinking water disinfection, since it is regarded as environmentally friendly, amendable to automation, inexpensive, easily operated and is known to inactivate a wide variety of microorganisms from bacteria to viruses and algae. We found that along with increasing the number of electrodes in our equipment from 2 to 24, the resistance of chlorine-generating electrolytic cell and specific work of electric current decreased. During the electrolysis the amount of generated Cl 2 increased along with the increase of chloride ion concentration in the solution and the intensity of electric current. The technological process parameters (flow rate, current intensity) have been established to obtain a predetermined amount of generated chlorine during the electrolysis process. A comparison of flow and circulating (3 times) regimes for electrolysis of tap water with chloride ion concentration below 10 mg/L showed that circulation is necessary to generate active chlorine (above 1 mg/L).
Food Microbiology
The efficacy of an electrochemical treatment in water disinfection, using boron-doped diamond electrodes, was studied and its suitability for the fresh-cut produce industry analyzed. Tap water (TW), and tap water supplemented with NaCl (NaClW) containing different levels of organic matter (Chemical Oxygen Demand (COD) around 60, 300, 550 AE 50 and 750 AE 50 mg/L) obtained from lettuce, were inoculated with a cocktail of Escherichia coli O157:H7 at 10 5 cfu/mL. Changes in levels of E. coli O157:H7, free, combined and total chlorine, pH, oxidationereduction potential, COD and temperature were monitored during the treatments. In NaClW, free chlorine was produced more rapidly than in TW and, as a consequence, reductions of 5 log units of E. coli O157:H7 were achieved faster (0.17, 4, 15 and 24 min for water with 60, 300, 500 and 750 mg/L of COD, respectively) than in TW alone (0.9, 25, 60 min and 90 min for water with 60, 300, 600 and 800 mg/L of COD, respectively). Nonetheless, the equipment showed potential for water disinfection and organic matter reduction even without adding NaCl. Additionally, different mathematical models were assessed to account for microbial inactivation curves obtained from the electrochemical treatments.