Disinfection Systems & Sanitization Methods Flashcards

How does ultraviolet (UV) disinfection work in pool water treatment systems?

Answer: UV light penetrates microorganisms and disrupts their DNA, preventing reproduction

UV systems expose water to ultraviolet light at a specific wavelength (typically 254 nm) that damages microbial DNA, inactivating pathogens without adding chemicals, though a residual sanitizer is still required.

What is a key limitation of ozone (O₃) as the sole pool sanitizer?

Answer: Ozone provides no residual disinfectant in the pool water after treatment

Ozone is a powerful oxidizer that destroys contaminants in the treatment chamber, but it rapidly dissipates and provides no measurable residual disinfection in the pool water, so a secondary sanitizer like chlorine is always required.

A saltwater chlorination system (electrolytic chlorine generator) produces chlorine by which process?

Answer: Passing an electrical current through sodium chloride (salt) solution to generate hypochlorous acid

An electrolytic chlorine generator (ECG/SWG) passes electricity through a dilute salt solution across titanium electrodes, splitting NaCl into sodium hypochlorite and hypochlorous acid — effective chlorine.

What is the function of cyanuric acid (CYA) in an outdoor pool?

Answer: It acts as a chlorine stabilizer, reducing UV degradation of free chlorine by sunlight

Cyanuric acid bonds loosely with chlorine, shielding it from ultraviolet light degradation and significantly extending the effective life of free chlorine in outdoor pools.

At what cyanuric acid (CYA) level does pool health guidance generally indicate that chlorine effectiveness becomes significantly compromised, requiring dilution or draining?

Answer: Above 100 ppm

Most health guidelines and the Model Aquatic Health Code (MAHC) recommend maximum CYA levels of 100 ppm, beyond which chlorine is so tightly bound that it cannot effectively inactivate pathogens in reasonable time.

What does Oxidation-Reduction Potential (ORP), measured in millivolts (mV), indicate about pool water?

Answer: The overall sanitizing power or disinfection effectiveness of the water

ORP measures the water's ability to oxidize and destroy contaminants; a higher ORP (typically 650–750 mV) indicates greater sanitizing effectiveness regardless of the specific sanitizer used.

Which alternative sanitizer system, sometimes called a 'mineral system,' uses silver and copper ions to inhibit algae growth and reduce the chlorine demand in pools?

Answer: Copper-silver ionization system

Copper-silver ionization systems release controlled amounts of copper (algaecide) and silver (bactericide) ions into pool water, reducing overall chlorine demand while providing supplemental sanitation.