Effect of different process conditions on the physicochemical and antimicrobial properties of plasma-activated water

The physicochemical properties of plasma-activated water(PAW)generated under different process conditions were investigated,and their changes under different storage conditions were also studied.The results showed that increasing the processing time and power,and decreasing generated water volume,could cause an increase in the redox potential,conductivity,and temperature of PAW,and a decrease in its pH.A slower dissipation of the reactive oxygen and nitrogen species in PAW was found on storage at 4℃in a sealed conical flask than on storage at room temperature.The inactivation ability of plasma-activated lactic acid(LA)to Listeria monocytogenes(L.monocytogenes)and Pseudomonas aeruginosa(P.aeruginosa)was higher than that of PAW or LA alone under the same experimental conditions.The results of this study may provide theoretical information for the application of PAW as a potential antimicrobial agent in the future.

A comparative effect of 3 disinfectants on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria

The disinfection effect of chlorine dioxide, chlorine and their mixture on heterotrophic bacteria, iron bacteria and sulfate-reducing bacteria in circulating cooling water was studied. The results of the test indicated that high purity chlorine dioxide was the most effective biocide in the 3 disinfectants, and with a dosage of 0.5 mg/L, chlorine dioxide could obtain perfect effect. High purity chloride dioxide could have the excellent effect with the pH value of 6 to 10, and could keep it within 72 h. Chlorine and their mixture couldn’t reach the effect of chlorine dioxide.

Experimental study on disinfection effect of different dose of rapid hand disinfectant

Purpose:To investigate the appropriate antiseptic handrubbing method.Methods:Seventy-four clinical nurses were randomly divided into two groups based on the number of disinfectant presses used,with group 1 using one-press and group 2 using twopresses.Sterilizing effects as a function of presses were compared and analyzed between the two groups.Results:Prior to hand disinfection,the hand sampling region resulted in 72 colony forming units for the 74 nurses.Following disinfection,only 2 colony forming units(p<0.001)were found.The analysis of drying time effects on the disinfection rate between the two groups showed a significant difference(p?0.049).Conclusion:In an effort to reduce the incidence of nosocomial infection,the medical personnel should sufficiently dry hands following handrubbing with disinfectant in a strict accordance with the six part washing technique for antiseptic handrubbing.

Disinfection Effects and Clinical Application of Sodium Dichloroisocyanurate Powder on Bacteria

With the continuous increase of large-scale pig farms,the disinfection of pig farm environment plays an extremely important part in the control and prevention of pig farm diseases in high-density breeding environment.As an important breeding place for pig farms,the farrowing house must be performed with scientific and standardized disinfection.In this paper,different disinfection modes were used to disinfect the empty farrowing houses of pig farms,and the total plate count,Escherichia coli,Staphylococcus aureus,and fungi were used as detection indicators to comprehensively evaluate the disinfection effect of the air microorganisms and the surface of the objects in the empty house after disinfection,with the aim to provide a basis for the establishment of a scientific pig farm environmental disinfection model.

Inactivation effect of pressurized carbon dioxide on bacteriophage Qβ and ΦX174 as a novel disinfectant for water treatment

The inactivation effects of pressurized CO2 against bacteriophage Qβ and ФX 174 were investigated under the pressure of 0.3-0.9 MPa, initial concentration of 107-109 PFU/mL, and temperature of 17.8℃-27.2℃. The optimum conditions were found to be 0.7 MPa and an exposure time of 25 min. Under identical treatment conditions, a greater than 3.3-log reduction in bacteriophage Qβ was achieved by CO2, while a nearly 3.0 log reduction was observed for phage ФX174. The viricidal effects of N2O （an inactivation gas with similar characteristics to CO2）, normal acid （HC1）, and CO2 treatment with phosphate buffered saline affirmed the chemical nature of CO2 treatment. The pumping cycle, depressurization rate, and release of intracellular substances caused by CO2 were its viricidal mechanisms. The results indicate that CO2 has the potential for use as a disinfectant without forming disinfection by-products.

Occurrence and formation of disinfection by-products in the swimming pool environment： A critical review

Disinfection of water for human use is essential to protect against microbial disease;however, disinfection also leads to formation of disinfection by-products（DBPs）, some of which are of health concern. From a chemical perspective, swimming pools are a complex matrix, with continual addition of a wide range of natural and anthropogenic chemicals via filling waters, disinfectant addition, pharmaceuticals and personal care products and human body excretions. Natural organic matter, trace amounts of DBPs and chlorine or chloramines may be introduced by the filling water, which is commonly disinfected distributed drinking water. Chlorine and/or bromine is continually introduced via the addition of chemical disinfectants to the pool. Human body excretions（sweat, urine and saliva） and pharmaceuticals and personal care products（sunscreens, cosmetics, hair products and lotions） are introduced by swimmers. High addition of disinfectant leads to a high formation of DBPs from reaction of some of the chemicals with the disinfectant.Swimming pool air is also of concern as volatile DBPs partition into the air above the pool.The presence of bromine leads to the formation of a wide range of bromo-and bromo/chloro-DBPs, and Br-DBPs are more toxic than their chlorinated analogues. This is particularly important for seawater-filled pools or pools using a bromine-based disinfectant.This review summarises chemical contaminants and DBPs in swimming pool waters, as well as in the air above pools. Factors that have been found to affect DBP formation in pools are discussed. The impact of the swimming pool environment on human health is reviewed.