Cooling systems offer an ideal environment for microbiological fouling. Take steps now to look for and treat scaling and fouling.

****!!!!****!!!!**** {Includes data table of studies of gas and liquid against specific pathogens on food} "ClO2 disinfects by oxidation through the one-electron transfer mechanism, resulting in a reduction to ClO2–...The inactivation may be reached by allowing permeability of the cell membrane by changing the configuration of lipids and protein which involve the oxidation of amino acids by the gas. The second option is due to the reaction with nucleic acid and/or protein structures... However, some research showed degradation in viral RNA, inducing genotoxicity or discontinuing replication of genome information." "At higher relative humidity, a greater reduction of pathogen population was reported. This might be explained due to the increment of the pores’ sizes in the bacteria due to swelling at high humidity, which allow penetration of the ClO2 molecule into the bacteria." "Gaseous ClO2 showed a negative impact on treated fruits and vegetables through enzymatic browning formation... is related to the deterioration of nutritional quality. However, additional treatments can be added to the gas exposure to inhibit browning..." "negative color change in spinach leaves, which occurred during storage after being exposed even to 50 ppm of gaseous ClO2. Also, treatments with higher concentrations may lead to bleaching of fruits and vegetables" "reaction rate was estimated to be... which is significantly higher than the reaction rate reported by previous researchers ... the chamber used here was stainless steel... likely increased the reaction with the walls, and created minor corrosion" "larger exposure surface area for the water in contact with the gas increased the overall decay rate" "some crevices in equipment could impact the effectiveness of the ClO2 gas treatment due to the time for gas to diffuse into the crevice" "the ClO2 gas concentration is surface area- and water volume-dependent" "Results showed an increase in the reaction rate due to water presence at different water volume and exposure surface area. After 7 days’ exposure at 3000 ppm of ClO2 gas, none of the selected plastics or elastomers showed a significance difference (p0.05) in the hardness value." "excitation wavelengths of ClO2 are near the ultraviolet and visible light... leads to dissociation into ClO + O or Cl + O2" " Further research can also be extended to determine the rate of ClO2 molecules dissolving into water, and the residuals form."

****!!!!****!!!!**** " In practice, based on a 10% chlorine excess compared with the stoichiometry and a 95% efficiency, 1.41 g of pure sodium chlorite and 0.61 g of chlorine will be required to produce 1 g of CℓO2." "obtained by oxidizing a solution of sodium chlorite using chlorine or hydrochloric acid" "Sodium chlorite solutions can be prepared from sodium chlorite powder. Water that has first been softened will need to be used to prevent calcium carbonate from precipitating."

****!!!!****!!!!**** {CDG Environmental} The present invention is for extremely pure solutions of chlorine dioxide, methods for making such solutions and to compositions and methods for storing, shipping and using such solutions. " " the vapor pressure of chlorine dioxide gas above aqueous solutions of the gas as a function of temperature and concentration" "Chlorine dioxide solutions can deteriorate in by chemical degradation into chlorine, oxygen, chlorite, chlorate, or other decomposition products.. these decomposition reactions either do not occur or occur at very slow rates in solutions made of pure water and ultra-pure chlorine dioxide." **** "salt substantially increases the rate of chlorine dioxide decomposition in solution" "rate of concentration loss through the walls of an HDPE 55 gallon drum ... is negligible compared to the concentration decay due to other factors." **!!** " *Such containers, prior to use, can be pre-treated by filling with a pre-treatment solution containing chlorine dioxide or with dilute chlorine dioxide gas prior to filling with solution. This saturates the walls with chlorine dioxide and greatly slows initial chlorine dioxide losses." *** "After an initial rapid rate of loss, the solution in PET bottles is almost as stable as that stored in glass" "There is no statistically significant difference in the stability of the solutions at different temperatures and salt concentrations for temperatures of less than about 25° C." "Chlorine dioxide solutions made by reacting sodium chlorite with chlorine in aqueous solution, which produces high concentrations of sodium chloride, are much less stable than solutions made using pure chlorine dioxide and pure water."

"We have studied the effects of chlorine dioxide fumigation on the reliability of electronic equipment using personal computers as examples of current commercial systems. Unit and subunit failure were objectively defined by standard commercial software. After the initial one-day exposures to the fumigation conditions, the systems were tested..."

This paper focuses on the connector failures due to decontamination and the associated failure mechanisms.

"sanitizing regimes on... stainless steel, wood, and rubber conveyor material." "Of the range of chlorine dioxide concentrations and contact time regimes evaluated for all surfaces, the most effective concentration/time regime applied was 100 ppm for 10 min. Reductions ranged from 0 to 4.5 log CFU/coupon. ***Chlorine dioxide was least effective when applied to wood.***"

****!!!!****!!!!**** "New compositions and methods are disclosed for decontaminating surfaces and enclosures that avoid problems such as salt deposits, corrosion and condensation that accompany the use of known methods. The process involves the use of chlorine dioxide solutions prepared by passing dilute chlorine gas over solid granular sodium chlorite to produce chlorine dioxide gas which is then collected in solution." "...mixing the gas with a carrier gas to produce a gas stream containing chlorine dioxide and disinfecting an enclosure. The gas can be produced by releasing chlorine dioxide gas from an aqueous chlorine dioxide solution containing less than 10% by weight of any of hydrochloric acid, hypochlorite ion, hypochlorous acid, or sodium chloride or it can be produced directly for use, as described above. When solutions are used it is preferred that they contain no more than 5%, or more preferably 2.5%, [etc] of... contaminants." "[Anthrax treatment:] As chlorine dioxide gas is stripped out of solution in this method, micro-droplets of solution became entrained in the resulting gas stream and were carried into the building. These droplets deposited a corrosive mixture of water and contaminants throughout the building space causing severe corrosion and other damage. Even where there was no corrosion, salt deposits had to be removed after decontamination was complete. In addition, the solution became hot as it was produced and when pumped into the stripper column (material transfer device) and contacted with air heated by the blowers, the gas stream was warm and humid. This resulted in severe condensation within the building when the warm, humid air contacted cooler air and cooler surfaces in the building. Large mechanical cooling units were used to partially dehumidify the air but a method was never found to control humidity and chlorine dioxide gas concentration simultaneously."

**** {Tested at 1 ppm and ph of 7 for 8 wks} "four different kinds of water pipes, two based on plastics, namely random polypropylene (PPR) and polyethylene of raised temperature (PERT/aluminum multilayer), and two made of metals, i.e., copper and galvanized steel, were put in a semi-closed system where ClO2 was dosed continuously. The semi-closed system allowed for the simulation of real ClO2 concentrations in common water distribution systems and to simulate the presence of pipes made with different materials from the source of water to the tap. Results show that ClO2 has a deep effect on all the materials tested (plastics and metals) and that severe damage occurs due to its strong oxidizing power in terms of surface chemical modification of metals and progressive cracking of plastics. These phenomena could in turn become an issue for the health and safety of drinking water due to progressive leakage of degraded products in the water."

****!!!!****!!!! {Materials suitable for Chlorine Dioxide containers} "Construction should be of dark or opaque/UV-blocking (preferred) oxidation-resistant plastic or glass. Some materials recommended include: -High Density Polyethylene (HDPE)- Polypropylene (PP)- Polyethylene Terephthalate (PET) (PETE)- Polyvinyl Chloride (PVC)- Polycarbonate (PC)- Glass (UV-blocking preferred)- Gasket materials; silicone, viton or EPDM" "DECORATIVE AND ORNAMENTAL FOUNTAINS 5 ppm residual chlorine dioxide level. Circulate water in normal operation of the system.... Repeat daily until desired results are achieved." "Selective Micro® Chlorine Dioxide Test Strips"

Previous studies showed that temperature and total organic carbon in drinking water would cause chlorine dioxide (ClO(2)) loss in a water distribution system and affect the efficiency of ClO(2) for Legionella control. However, among the various causes of ClO(2) loss in a drinking water distribution …

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{ Fumigation against Bacillus anthracis} "Results from the 750 ppmv ClO2 fumigation suggest that 750 ppmv was more damaging to Category 4 materials than the 3000 ppmv ClO2 fumigation. Although both fumigation concentrations resulted in severe physical damage to the computers by promoting rusting and corrosion, only the computers exposed to 750 ppmv ClO2 experienced unrecoverable failures. It is not readily understood why the lower concentration (same RH) fumigation was more damaging; however, the same sample size and difference in computer batches cannot be ruled out as confounding parameters." "fumigation with ClO2 produced large amounts of dust inside the computers... an acrid smell (attributed to hydrogen chloride)... Vacuuming of the visible dust not only served to remove the majority of this probable health hazard and prevent the dust from being spread... also may have assisted in keeping all computers almost fully operational after an entire calendar year. "

"The corrosion scale will cause much more significant ClO2 loss in corroded iron pipes of the distribution system than the total organic carbon t... The application of ClO2 in the water distribution system using cast-iron pipes is not recommended unless measures to prevent corrosion are fully implemented . Although ClO2 loss caused by corrosion scale was much slower in the copper pipe ..., it may still be necessary to prevent the corrosion and unnecessary loss of disinfectant"