Feasibility of supercritical COâ‚‚ treatment for controlling biofouling in the reverse osmosis process.

Physical cleaning and/or chemical cleaning have been generally used to control biofouling in the reverse osmosis (RO) process. However, conventional membrane cleaning methods to control biofouling are limited due to the generation of by-products and the potential for damage to the RO membranes. In this study, supercritical carbon dioxide (SC CO(2)) treatment, an environmentally friendly technique, was introduced to control biofouling in the RO process.

Bactericidal effect of supercritical Nâ‚‚O on Staphylococcus aureus and Escherichia coli.

The aim of this study is to investigate the bactericidal effect of supercritical nitrous oxide (SC N(2)O) on both typical Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli while varying the operating conditions including the suspending medium (nutrient broth, phosphate buffered saline, phosphate buffer, phosphate buffer containing oleic acid), pressure, temperature, mixing intensity, and working volume (the ratio of the sample volume to the reactor volume). Approximately 7 log of both S. aureus and E.

Inactivation behavior of Pseudomonas aeruginosa by supercritical Nâ‚‚O compared to supercritical COâ‚‚.

Interest is growing for a non-thermal sterilization technique in the food and pharmaceutical industries in order to ensure microbiological safety without the deterioration of product quality. In this study, supercritical nitrous oxide (SC Nâ‚‚O) treatment was carried out in a multi-batch system to examine its bactericidal effect and characteristics, which largely remains unclear. The effect of operating pressure, temperature, mixing intensity, and working volume ratio (defined as the ratio of sample volume to the reactor volume to be filled with SC fluids) on the inactivation efficiency of SC Nâ‚‚O were investigated in comparison with supercritical carbon dioxide (SC COâ‚‚) treatment.

Influence of membrane surface properties on the behavior of initial bacterial adhesion and biofilm development onto nanofiltration membranes.

In order to investigate biofouling problems, the fundamental behaviors of initial bacterial adhesion and biofilm development on four different nanofiltration (NF) membranes were evaluated using Pseudomonas aeruginosa PAO1 as a model bacterial strain. Initial cell adhesion was considerably higher on an aromatic polyamide-based NF membrane with a hydrophobic and rough surface, whereas cell aggregation on a polypiperazine-based NF membrane with a relatively hydrophilic and smooth surface was lower. Moreover, significant differences in the structural heterogeneity of the biofilms were observed among the four NF membranes.

Inactivation of Ascaris eggs in soil by microwave treatment compared to UV and ozone treatment.

This study reports on the effect of microwave radiation for inactivation of Ascaris lumbricoides eggs in 25 g of soil compared to ultraviolet irradiation and ozone expose. Microwave radiation at 700 W with 14% water content (w/w) achieved approximately 2.5 log inactivation of eggs in soil within 60s.

Inactivation of Pseudomonas aeruginosa biofilm by dense phase carbon dioxide.

Dense phase carbon dioxide (DPCD) is one of the most promising techniques available to control microorganisms as a non-thermal disinfection method. However, no study on the efficiency of biofilm disinfection using DPCD has been reported. The efficiency of DPCD in inactivating Pseudomonas aeruginosa biofilm, which is known to have high antimicrobial resistance, was thus investigated.