Chlorine Speciation and pH Effectiveness
One mechanism from Chapter 9: Microbiology.
flowchart LR A["Free chlorine residual"] --> B["HOCl, strong biocide"] A --> C["OCl-, weak biocide"] B -->|"rising pH"| C C -->|"falling pH"| B D["pH 6.5: about 90 percent HOCl"] --> E["Excellent kill"] F["pH 7.5: about 50 percent HOCl"] --> G["Good kill"] H["pH 8.5: about 8 percent HOCl"] --> I["Poor kill"]