Ozone disinfection

Starting in the spring of 2006, new ozone systems will be in place at Penitencia and Santa Teresa water treatment plants. Ozone is a powerful disinfectant, minimizes harmful disinfection byproducts and removes unpleasant odors and tastes.

The first step in ozone disinfection is to generate ozone gas. Liquid oxygen is transported to the plant and stored for use. It is then vaporized into oxygen gas. When electric currents are applied to a flow of oxygen gas, some oxygen molecules (O2) are split and bond to other oxygen molecules to form ozone molecules (O3).

Next, water that has finished the flocculation process is piped into the ozone contactor basins. Ozone is bubbled up through the water. Water typically will spend 15

Ozone generation

minutes in this system, traveling up and down a series of columns to maximize the contact with the ozone gas.

The newly ozone treated water then moves on through the pipes to the next step, filtration.

Meanwhile, the ozone that was used in the process is converted back into harmless oxygen and released into the atmosphere.