OZONE SIDE-STREAM SYSTEM DESIGN OPTIONS AND OPERATING CONSIDERATIONS

Disinfection with ozone is achieved by CT product, where “C” is residual ozone concentration and “T” is reaction time. Ozone residual is developed after ozone gas is dissolved into the water. Ozone dissolution is most often achieved by either bubble-diffuser or side-stream ozone systems.Side-stream ozone systems are different from bubble-diffuser ozone systems in many ways.Ozone addition occurs outside of the ozone contactor.Additional energy is used due to side-stream pump operation.Equipment maintenance can be completed independent of ozone contactor operation.Ozone contactor size and shape can have unique design features, such as pipeline contacting or shallow-depth basins.Side-stream ozonation is a treatment technique that is gaining in popularity at larger and larger plants. Ozone generators can now operate at elevated ozone concentration, which improves the economics for installing and operating side-stream processes. Two different side-stream arrangements are discussed in this paper. The arrangements differ with the presence or absence of a de-gas vessel. The de-gas vessel option is more expensive in terms of capital and operating cost, but might be the chosen option for particular contactor configurations. Issues and considerations for installing a de-gas vessel are discussed in this paper.