Large quantities of fresh water are used intensively in the washing, cutting, peeling and disinfection of fruits and vegetables, resulting in high solids loading of the wash-water. Review of the literature shows that ...Large quantities of fresh water are used intensively in the washing, cutting, peeling and disinfection of fruits and vegetables, resulting in high solids loading of the wash-water. Review of the literature shows that there is limited information available on how to treat this wash-water on-site. Accordingly, an investigative program was established by sampling wash-water from two industrial partners processing root vegetables to determine the best available approach. Bench scale technologies tested for solids removal were dissolved air flotation （DAF） and centrifuge, followed by ultraviolet （UV） disinfection to evaluate the potential for water reuse. The results showed that DAF and centrifuge were able to remove solids at an efficiency greater than 95%. The DAF process was also able to remove higher levels of dissolved matter and nutrients in comparison to the centrifuge. The DAF process was also able to produce waters with higher transmittance, which leads to improved filtration and UV disinfection for water reuse. Membrane filtration feasibility testing showed that high quality waters can be produced as low as 2 NTU and 4 NTU, following pretreatment with DAF and centrifuge, respectively. However, filtration was unable to remove E. coll. Collimated beam results show that UV disinfection is needed to allow for water reuse.展开更多
Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present pr...Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.展开更多
This work aimed to study the inactivate kinetics of Staphylococcus aureus （S. aureus） in artificial seawater by ultraviolet radi- ation, establish relationships between model parameters and growth phases, and explai...This work aimed to study the inactivate kinetics of Staphylococcus aureus （S. aureus） in artificial seawater by ultraviolet radi- ation, establish relationships between model parameters and growth phases, and explain the mechanization of UV disinfection by molecular biological detection. Investigations were carried out for the validation of Chick-Watson, Collins-Selleck, Horn and Biphasic models when S. aureus was in stationary phase （t=14 h）. The results showed that the Biphasic kinetic model＇s R2 turned out to be the highest one （R2=0.9892） and RMSE was less than 0.5 （RMSE =0.2699）. The Biphasic kinetic model was better fit for ultraviolet disinfection than the other three models under the circumstance of this experiment and chosen to fit the ultraviolet disinfection curves for microorganisms at three growth phases. The sensitivity of microorganisms under ultraviolet radiation was in the following order： in exponential phase 〉 in stationary phase 〉 in lag phase by comparing the indexes of the Biphasic model （kl and x）. Besides, agarose gel electrophoresis was used in order to directly assess the damage to DNA of mi- croorganisms that were exposed to the different dose of UV irradiation. The results revealed that DNA damage caused by UV radiation was an important reason for the microorganism inactivation and as the UV dose increased, there was greater damage caused in DNA.展开更多
文摘Large quantities of fresh water are used intensively in the washing, cutting, peeling and disinfection of fruits and vegetables, resulting in high solids loading of the wash-water. Review of the literature shows that there is limited information available on how to treat this wash-water on-site. Accordingly, an investigative program was established by sampling wash-water from two industrial partners processing root vegetables to determine the best available approach. Bench scale technologies tested for solids removal were dissolved air flotation （DAF） and centrifuge, followed by ultraviolet （UV） disinfection to evaluate the potential for water reuse. The results showed that DAF and centrifuge were able to remove solids at an efficiency greater than 95%. The DAF process was also able to remove higher levels of dissolved matter and nutrients in comparison to the centrifuge. The DAF process was also able to produce waters with higher transmittance, which leads to improved filtration and UV disinfection for water reuse. Membrane filtration feasibility testing showed that high quality waters can be produced as low as 2 NTU and 4 NTU, following pretreatment with DAF and centrifuge, respectively. However, filtration was unable to remove E. coll. Collimated beam results show that UV disinfection is needed to allow for water reuse.
文摘Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.
基金supported by the National Natural Science Foundation of China(Grant Nos.51179037&51209053)
文摘This work aimed to study the inactivate kinetics of Staphylococcus aureus （S. aureus） in artificial seawater by ultraviolet radi- ation, establish relationships between model parameters and growth phases, and explain the mechanization of UV disinfection by molecular biological detection. Investigations were carried out for the validation of Chick-Watson, Collins-Selleck, Horn and Biphasic models when S. aureus was in stationary phase （t=14 h）. The results showed that the Biphasic kinetic model＇s R2 turned out to be the highest one （R2=0.9892） and RMSE was less than 0.5 （RMSE =0.2699）. The Biphasic kinetic model was better fit for ultraviolet disinfection than the other three models under the circumstance of this experiment and chosen to fit the ultraviolet disinfection curves for microorganisms at three growth phases. The sensitivity of microorganisms under ultraviolet radiation was in the following order： in exponential phase 〉 in stationary phase 〉 in lag phase by comparing the indexes of the Biphasic model （kl and x）. Besides, agarose gel electrophoresis was used in order to directly assess the damage to DNA of mi- croorganisms that were exposed to the different dose of UV irradiation. The results revealed that DNA damage caused by UV radiation was an important reason for the microorganism inactivation and as the UV dose increased, there was greater damage caused in DNA.
