"The two viability methods produced significantly different results (P 0.05). Products of disinfectant concentration" "excystation is not an adequate viability assay." "Purified oocysts originating from three different suppliers were evaluated and showed marked differences with respect to their resistance to inactivation when using chlorine dioxide" "Finally, the study compared the relationship between easily measured indicators, including Bacillus subtilis (aerobic) spores and Clostridium sporogenes (anaerobic) spores, and C. parvum oocysts. The bacterial spores were found to be more sensitive to chlorine dioxide"

***!!!!** {Includes chlorine dioxide concentration levels that oxidize various medicines} "The formation of undesirable by-products can be controlled by minimizing the dose of ClO2 and applying post-treatment using, for example, ferrous iron (Fe2+) or sulfite (SO3 2-), which reduces ClO2 and chlorite residuals to chloride [22,23]. The removal of ClO2 and chlorite residuals allows higher levels of ClO2 to be used for treatment providing effective micropollutant removal. " "Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended nitrogen removal (low COD) and one without (high COD). "

****!!!!****!!!**"Unlike chlorine, ClO2 will react to form mainly inorganic disinfection by products, the predominant species being chlorite. Chlorite will subsequently reduce to form harmless chloride. The speed of this reaction depends upon a number of factors, however within saltwater conditions this can be as low as 5 minutes." "Poorly designed or tuned chlorine dioxide generation equipment can lead to the production of chlorate" "Modern generation systems such as those produced by Scotmas are able to monitor the downstream residual DBP and adjust the dose rate to ensure that environmental limits are not breached. In special cases, downstream reactions can be used to remove excess chlorite residual from the water stream." "It is important to note that the disinfection by products of chlorine dioxide are easily managed with the correct experience and advice, and do not present nearly the same scale of problem as found with other biocides with a higher oxidation potential. Unlike ozone (O3), chlorine dioxide does not oxidise bromide (Br-) ions into bromate ions (BrO3-) which have been identified as carcinogenic. Additionally, chlorine dioxide does not produce large amounts of aldehydes, ketones, or other disinfection by products that originate from the ozonisation of organic substances."

****!!!!**** "Chlorine dioxide chemistry works by selective oxidation, targeting the biocide where it is needed most." "Generally Chlorine Dioxide (ClO2) rapidly oxidises phenol type compounds, secondary and tertiary amines, organic sulphides and certain hydrocarbon polycyclic aromatics such as benzopyrene, anthracene and benzoathracene. In general, Chlorine Dioxide will not react on double carbon bonds, aromatic cores, quinionic and carboxylic structures as well as primary amines and urea. Commercial applications have shown that Chlorine Dioxide can effectively oxidise many compounds considered to be waste and water pollutants. The table below lists a selection of pollutants found in various industries from our files, and demonstrates the wide range of possible applications for Chlorine Dioxide... Aldehydes... Amines and Mercaptans" "Chlorine Dioxide, however reacts with THM precursors primarily by oxidation to make them non-reactive or unavailable for THM production."

"Our KyroCAPS represent an innovative and patented capsule system that does not affect the smell, taste or pH value of the water."

****!!!!**** "the reaction between the ferrous ion and chlorite is very fast (5–15 s) over a range of pH 6.5–8.0; in this condition a ferrous ion dose of 3.31 mg Fe/mg ClO2 completely reduced chlorite to chloride, producing minimal residual soluble iron. For pH higher than 8.0–8.5, chlorite removal is lower due to the natural transformation of the ferrou ions to ferric hydroxide. Within these pH values, chlorite can be removed completely with ferrous ion concentrations higher than the stoichiometric value. Moreover, the application of ferrous salts for chlorite removal during the coagulation process enhances the performance of the coagulation and flocculation treatment"

{Includes chart of critical levels for pathogens in water} "Shock treatment is recommended twice a year and usually requires a concentration of 20-50ppm chlorine dioxide be maintained for 12 hours, and then the irrigation system thoroughly rinsed before irrigation begins again, due to risk of phytotoxic effects with high concentrations. After shock treatment, a continuous treatment of 0.25ppm residual chlorine dioxide is usually sufficient to prevent regrowth of biofilm. " "The optimum chlorine dioxide range to treat biofilms and common plant pathogens is 0.25 to 3.3 ppm"

****!!!!****"If you buy a 2% CLO2 product (Oxine), you are actually getting a 3.35% Sodium Chlorite in that jug or drum. It is essentially a 1.67 multiplier from the percentage of CLO2 that product claims." "Sodium Chlorite is widely used as a sanitizer and can be effective at inhibiting bacteria. It is important to know that chlorite solutions can carry anti-microbial claims listed as static or stasis by the EPA. That means chlorite solutions can inhibit or prevent bacteria growth of present organisms" [without necessarily destroying them] "we have found the liquid inorganic acids like LpH 100 work best and allow for less acid to be used with higher conversion to CLO2." "Contact time with your acid or ‘activator’ and pH of the working solution your acid is creating. Those two dynamics will determine how much Chlorine Dioxide you actually generate." "When using 5% stabilized CLO2 products like Pro Oxine after you achieve proper activation you will convert about 25% to 30% of that solution to CLO2. 70 to 75% of that solution will remain chlorite and be a part of your TOTAL working solution. The remaining sodium chlorite is important and will play a critical role in how well your product works over time." "Bio-Cide’s AANE [Automatic Activation Non Electric] system... to deliver product without ever having to mix products but allows for proper contact time and pH in your working solution to generate FREE CLO2 in your water system. The system is very easy to set up and can be used with any pump system you already have" "So you can essentially have 1.8 ppm TOTAL and .8 ppm FREE under the potable water claim approved by the EPA." " you never have to turn off your system to run other supportive care products or water soluble antibiotics. Since CLO2 is a ‘selective’ oxidizer it doesn’t seem to negatively affect these other products"

****** "The most common method of generating ClO2 is through the reaction of chlorine gas with a solution of sodium chlorite. Theoretically, 1 lb of chlorine gas is required for each 2.6 lb of sodium chlorite. However, an excess of chlorine is often used to lower the pH to the required minimum of 3.5 and to drive the reaction to completion. Sodium hypochlorite can be used in place of the gaseous chlorine to generate chlorine dioxide. This process requires the addition of sulfuric or hydrochloric acid for pH control. Other methods used for chlorine dioxide generation include:..." "Complex organic molecules and ammonia are traditional chlorine-demand materials that do not react with chlorine dioxide. " "The chemical behavior and oxidation characteristics of aqueous chlorine dioxide are not well understood because of the difficulty in differentiating aqueous chlorine-containing species." "Chlorine dioxide consumed in water treatment reactions reverts to chlorite ions (ClO2-), chlorate ions (ClO3- ), and chloride ions (Cl -)." "As a gas, chlorine dioxide is more irritating and toxic than chlorine. Chlorine dioxide in air is detectable by odor at 14-17 ppm, irritating at 45 ppm, fatal in 44 min at 150 ppm, and rapidly fatal at 350 ppm. Concentrations greater than 14% in air can sustain a decomposition wave set off by an electric spark. The most common precursor for on-site generation of chlorine dioxide is also a hazardous material: liquid sodium chlorite. If allowed to dry, this powerful oxidizing agent forms a powdered residue that can ignite or explode if contacted by oxidizable materials. The hazardous nature of chlorine dioxide vapor and its precursor, and the volatility of aqueous solutions of chlorine dioxide, require caution in the design and operation of solution and feeding equipment."

****!!!!****** {Includes equations for predicting impact of variables in determining quantity of byproducts} "At 20oC, pH 7, 70-80% of chlorine dioxideinjected was converted to chlorite and 0-10% of that was transformed into chlorate within 120 min with 2.91 mg/Lof DOC. The amount of chlorite formed also increased when pH and temperature increased. As DOC content increased,the residual chlorine dioxide decreased but the amount of chlorite and chlorate were increased. These experimentsrevealed that chlorate was a dominant by-product under UV irradiation."

***** 2020 "Chlorine dioxide (ClO2) has emerged as a promising alternative to free chlorine for water disinfection and/or pre-oxidation due to its reduced yields of chlorinated disinfection byproducts...""ClO2− serves as a radical generator, a light competitor and a radical/ozone scavenger. ClO2− reduces the concentrations of radicals and ozone in the UV/chlorine process. UV photolysis of ClO2− only generates HO• under drinking water relevant conditions. ClO3− is mainly generated from oxidation of ClO2− by HO• in the UV/chlorine process."

***** 2020 "Chlorine dioxide (ClO2) has emerged as a promising alternative to free chlorine for water disinfection and/or pre-oxidation due to its reduced yields of chlorinated disinfection byproducts. ClO2 decomposes to form chlorite (ClO2-), which influences the following advanced oxidation processes (AOPs) for micropollutant abatement in drinking water. This study aims at investigating the effects of ClO2- on the concentrations of reactive species (e.g., radicals and ozone) and on the formation of chlorate in the UV/chlorine AOP. Results showed that the concentration of ClO· in the UV/chlorine process remarkably decreased by 98.20-100.00% in the presence of ClO2- at concentration of 0.1-1.0 mg·L-1 as NaClO2. The concentrations of HO· and ozone decreased by 42.71-65.42% and by 22.02-64.31%, respectively, while the concentration of Cl· was less affected (i.e., 31.00-36.21% reduction). The overall concentrations of the reactive species were differentially impacted by ClO2-'s multiple roles in the process. UV photolysis of ClO2- generated HO· but not Cl·, ClO· or ozone under the drinking water relevant conditions. ClO2- also competed with chlorine for UV photons but this effect was minor (< 1.0%). The radicals/ozone scavenging by ClO2- outcompeted the above two to lead to the overall decreasing concentrations of the reactive species, in consistency with the kinetic model predicted trends. ClO2- reacted with radicals and ozone to form chlorate (ClO3-) but not perchlorate (ClO4-). HO· played a dominant role in ClO3- formation."

***!!!!*** {Includes table of pathogen effectiveness levels} "Chlorite is the major inorganic by-product of the reaction of chlorine dioxide in water. Usually, the amount of chlorite formed will be 40-60% of the amount of chlorine dioxide which has reacted. " "Chlorine dioxide systems: acid chlorite and electrochemical generators "Typical chlorite yield for an acid-chlorite generator varies between 65-68%. Overall conversion efficiency is much lower than this as much of the acid remains unreacted." "Chlorine Dioxide ClO2 will inactivate pathogenic micro-organisms at the same rate between pH 5 and 9. This makes it ideal for disinfection of potable water and process water where the pH is up around 8.0." "ClO2 is approximately 5 times more soluble than chlorine and 50 times more soluble than ozone." "Chlorine Dioxide Reaction with Inorganic Compounds--Ammonia Nitrogen... Iron... Manganese..." "Sulfur Compounds... Cyanide..." "Oil and Gas... frac water"

"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"

****{Summary of specific characteristics***a 35 mg/L chlorine dioxide solution stored in a high-density Polyethylene Terephthalate (PETE) container for 45 days resulted in a 3% loss.. In contrast, the same study stored chlorine dioxide in a clear glass container for 31 days which resulted in a 12% gain, possibly due to continuing formation of chlorine dioxide from chlorite. Another study showed a 6.2% overall gain in chlorine dioxide concentration after 252 days of storage in a PETE container... Chlorite and chlorate show no disinfection capabilities and may cause adverse health effects in children... CTs required for a 2-log virus inactivation were 13 – 20 times higher at a pH of approximately 6 compared to a pH of 9 and 10... two to three-fold increase in inactivation rates per 10° C water temperature increase... bentonite appeared to offer protection or shield the viruses from chlorine dioxide... disinfection capability decreases in more turbid waters since microorganisms are protected by solid particles in water, protected by aggregation or clumping, and protected by loss of chlorine dioxide residual from oxidation of organic matter... Chlorine dioxide should easily achieve a 6-log *bacteria* inactivation at low temperatures and low pHs if chlorine dioxide is used for disinfection of more resistant viruses and cysts." "Colder water temperatures require higher CT values. Use a two-fold increase in CT for every 10° C decrease. Use longer contact time instead of higher dosages to achieve higher CT values. "

*****"[Note: Some statements about corrosion, reaction with phenols, Cl also released during some specific reactions, etc may have some inaccuracies] Like ozone and chlorine, chlorine dioxide is an oxidizing biocide and not a metabolic toxin. This means that chlorine dioxide kills microorganisms by disruption of the transport of nutrients across the cell wall, not by disruption of a metabolic process." "Unlike chlorine, Chlorine dioxide is effective at pH between 4 and 10. No dumping and filling with fresh water required;" "Chlorine dioxide can be used as a spray. All parts therefore, can easily be reached;" In scrubbers: "In scrubbers, Usually, a very low chlorine dioxide residual, around 0.2-ppm, is sufficient to ensure odour control." {includes effects on specific foods when rinsed}