The Water Cycle
Water in a Pool
An ozone generator
The use of ozone in water disinfection is to purify the water as it passes through the plant room. Ozone ruptures the bacterium cell wall and therefore kills the microbe without leaving a disinfectant residual. It also doesn't depend on diffusion into the cell wall, unlike chlorine. Ozone enhances purity so the chlorine can be available as free chlorine for the pool.
Ozone is a bluish gas, the O3 molecule is symmetrical and bent. The dihedral angle is 117 degrees, the O-O bond length is 1.28 angstroms. Ozone can appear naturally around electrical equipment: it is generated on site. An alternating current of around 12KV is passed through an air gap between a high voltage electrode and a glass dielectric. This causes about 20-30 g/m3 ozone. This does depend on the volume of gas initially used, the concentration, the voltage and frequency of the current, the temperature of the cooling water and the dew point of air.
An ozone molecule
Ozone decomposes exothermically, the heat of decomposition is around -142 KJ/mol. It does decompose slowly though at 250 degrees Celsius in the absence of catalysts or UV. The heat produced in the discharge is cooled, the overall efficiency should be about 20W/g of ozone. Ozone must mix with all water, it is relatively insoluble in warm water - the solubility is 3mg/l at 30 degrees Celsius. The generator comprises of a booster pump forcing water through an injector which draws air / ozone form the generator into the mixture. Intimate mixing of bubbles is effected, the transfer is 90%. The entrained air is removed otherwise the air would travel to the pool and cause a loss of clarity.