5.7.1 Mixed oxidant gases system
This is a relatively new system of disinfection. It involves electrolysis of high-purity NaCl brine to produce a mixture of chlorine dioxide, ozone and hypochlorite. This mixture is separated within the electrochemical cell by a membrane, or by exploiting density difference, and is then metered into the water requiring disinfection. The mixed oxidant gases are generated on demand and this is a great safety advantage, compared with having storage tanks of chlorine on site. The source for the disinfectant (high-purity NaC1) is relatively inexpensive and the mixed oxidants are more effective than chlorine alone in disinfection. Importantly, the mixed oxidant gases yield substantially lower levels of disinfection by-products than chlorine gas or hypochlorites.
The disadvantage of the mixed oxidant gases system (sometimes called MOGGOD – mixed oxidant gases generated on demand) is that it requires extensive skilled maintenance of the electrochemical and dosing systems.