Inactivation of Naegleria gruberi cysts by chlorinated cyanurates

  title={Inactivation of Naegleria gruberi cysts by chlorinated cyanurates},
  author={Jan Engel and Alan J. Rubin and Otis J. Sproul},
  journal={Applied and Environmental Microbiology},
  pages={1157 - 1162}
The resistance of Naegleria gruberi cysts to chlorine in the presence of cyanuric acid was compared at pH 5 and 7. An amperometric membrane electrode was used to measure HOCl concentrations independently of the chlorinated cyanurate species, thus permitting an analysis of the role of free chlorine versus chlorinated cyanurates in cyst inactivation. In the presence of cyanuric acid, the products of the HOCl residual and the contact time required for 99% cyst inactivation were 8.5 mg . min/liter… 

The effect of cyanuric acid on the disinfection rate of Cryptosporidium parvum in 20-ppm free chlorine.

Current public health recommendations for hyperchlorination and pool remediation are insufficient for pools using cyanurate-stabilized chlorine to achieve a three log inactivation of the parasite.

Application of ozone disinfection to remove Enterococcus seriolicida, Pasteurella piscicida, and Vibrio anguillarum from seawater

Results strongly suggest that ozone treatment at more than 1.0 mg of TROs per liter for several minutes is able to disinfect seawater for mariculture efficiently.

Chlorinated cyanurates in drinking water: Measurement bias, stability, and disinfectant byproduct formation

The current research investigated measurement bias in N,N-diethyl-p-phenylenediamine (colorimetric and portable parallel analyzer), indophenol, amperometric titration, andAmperometric electrode free chlorine methods to inform practical considerations of disinfectant residual stability and regulated DBP formation.

Assessing the Impact of Cyanuric Acid on Bather’s Risk of Gastrointestinal Illness at Swimming Pools

Current regulatory codes for swimming pool disinfection separately regulate free chlorine (FC) and cyanuric acid (CYA). It is well-known that CYA affects disinfection rates by reversibly binding to

A Drinking Water Relevant Water Chemistry Model for the Free Chlorine and Cyanuric Acid System from 5 to 35 °C.

The current research used a simplified version of the full model (simple model) and estimated the unknown temperature dependence of the two remaining equilibrium constants (K7a and K9a) required for the simple model.

Chlorinated Cyanurates: Review of Water Chemistry and Associated Drinking Water Implications

  • D. Wahman
  • Chemistry
    Journal - American Water Works Association
  • 2018
This review summarizes the existing water chemistry associated with dichlor and trichlor use as a chlorine source in drinking water along with the associated implications.



Pseudomonas aeruginosa for the evaluation of swimming pool chlorination and algicides.

Concentrations of ammonia and the chlorine stabilizer, cyanuric acid, which could be expected in swimming pools decreased the rate of kill by chlorine of the potential pathogen, Pseudomonas

Factors influencing the effectiveness of swimming pool bactericides.

Techniques for culturing, harvesting, and testing bacteria to evaluate bactericidal chemicals for swimming pools are described and faster rates of kill of S. faecalis were obtained with 100 mg of cyanuric acid per liter plus 0.5 mg of chlorine per liter alone.

Resistance of pathogenic Naegleria to some common physical and chemical agents

  • S. L. Chang
  • Biology
    Applied and environmental microbiology
  • 1978
Concentration-contact time curves yielded concentration coefficient values that point to superchlorination as an effective means of destroying the cysts if free residuals are used as a guide and allowance is provided for low temperature and/or high pH waters.

Differences in destruction of cysts of pathogenic and nonpathogenic Naegleria and Acanthamoeba by chlorine

This study yields information needed for the destruction of amoebic cysts in drinking water and swimming pools and gives some explanation for the occurence of Acanthamoeba strains in these waters.

Effect of disinfectants on pathogenic free-living amoebae: in axenic conditions

The amoebicidal properties of chlorine, chlorine dioxide, ozone, and deciquam 222 were examined in axenic conditions. Naegleria spp. were found to be more sensitive to chlorine and chlorine dioxide

An evaluation of the inhibitory influence of cyanuric acid upon swimming pool disinfection.

An evaluation of the effect of cyanuric acid on the bactericidal properties of chlorine under laboratory conditions at 200 C, approximately the conditions developed by Butterfield, et al, found that at a pH of 7.0, the time required to effect a 99 per cent kill was 0.5 minutes.

Virulent Naegleria fowleri in indoor swimming pool.

Investigations did not reveal any new case of PAME in relation with the occurrence of pathogenic N. fowleri in the swimming pool and incubation temperature did not inhibit a simultaneous growth of amoebae of the genera Acanthamoeba, Flabellula, Hartmannella and Vahlkampfia in the primocultures.

Chloroisocyanurates in the treatment of swimming pool water

Chlorine Residual Measurement Cell: The HOCI Membrane Electrode

There is need for a method to measure only the effective (HOCI) fraction of free chlorine residuals, which is the next most effective chemically disinfectant form of chlorine, and at normal pHs is present in chlorine solutions.

Disinfection of amoebic cysts in water with free chlorine

L'acide hypochloreux est la forme de chlore la plus efficace pour la desinfection, pour tous les pH testes