Chlorine dioxide is a disinfectant used worldwide. In this article, a new enzymatic method for the determination of chlorine dioxide has been developed. This rapid spectophotometric assay is able to detect from 0.2 to 4 mg/liter of chlorine dioxide. The method is based on the capacity of horseradish peroxidase to decolorize reactive yellow 17 in the presence of chlorine dioxide. The effects of ...

Persistence of Bacillus atrophaeus subsp. globigii spores on corroded iron coupons in drinking water was studied using a biofilm annular reactor. Spores were inoculated at 10(6) CFU/ml in the dechlorinated reactor bulk water. The dechlorination allowed for observation of the effects of hydraulic shear and biofilm sloughing on persistence. Approximately 50% of the spores initially adhered to the...

A flow injection analysis (FIA) method for the determination of four residual chlorine species, namely combined available chlorine (CAC), free available chlorine (FAC), total available chlorine (TAC) and chlorite (ClO2-) was developed using a flow-through triiodide-selective electrode as a detector. An important strategy of speciation studies utilized the kinetic discrimination of reactions bet...

To evaluate the performance of chlorine disinfection in drinking water plants, managers use as an indicator the concentrations of residual chlorine within the distribution system. Because of the residence time of water in storage tanks and in distribution pipelines, data that reflect residual chlorine concentrations for a given applied dose are only available after a certain time delay. Consequ...

The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. An appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction...

Actinometry has been used as the basis of a successful sensor for controlling uorine concentration in uoro-carbon plasmas commonly employed in etching. An analogous sensor would be useful for chlorine plasmas as well. One problem with actinometry in Cl2 plasmas is that excitation can occur by electron impact dissociation and by dissociative attachment, leading to potential ambiguity between the...

We report our ten-year experience of hyperchlorination, thermal shock, chlorine dioxide, monochloramine, boilers and point-of-use filters for controlling legionella contamination in a hospital hot water distribution system. Shock disinfections were associated with a return to pre-treatment contamination levels within one or two months. We found that chlorine dioxide successfully maintained leve...

The Swimming Pool Water Disinfectant Test Method of the Association of Official Analytical Chemists was used to determine the effect of the accepted level of 2 ppm of some commercial quaternary ammonium algicides on the germicidal activity of chlorine. Accurate determinations on the amounts of residual available chlorine in chlorine-quaternary mixtures could not be made by the usual chemical me...

The formation of disinfection by-products (DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide (DEET) and ibuprofen (IBP) by the ultraviolet irradiation (UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H2O2 process. The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times...

The calorific values and the chlorine contents of refuse-derived fuels were measured in the pilot combustion plant (PCP) by means of combustion experiments followed by mass and energy balancing. This plant reaches an increased precision by measuring the integrated values throughout the whole experimental period of three hours, based on a fuel capacity of 10 kg per test, allowing a more reliable...