How to Add Ozone to Treat VOCs
Every application we address seems to have its own peculiarities. So, this section is basic in concept. If we consider ozone as a form of combustion, the concept is better understood. Ozone does not eliminate the VOC threat. It modifies that gas to what we expect to be a less volatile or harmful form. Because of the reactive nature of ozone, we do not want to inject ozone into the workplace. It is best applied in the exhaust air system allowing the opportunity for ozone to mix with the gases prior to exhaust into the outside air.
Treating gases with VOCs does not preclude the need to filter particulates as part of the pre-treatment by ozone. In fact, ozone is likely most effective in the last stage of exhaust air treatment. Ozone is a rapid paced application that quickly reacts with the air exhausts.
Ozone should not be part of the exhaust process in a direct line application. It should be an injection process with a fan-driven fitting that flows into the exhaust air. Protect the ozone production equipment from dirty air, high humidity, and provide an area for routine maintenance. To prevent backup of the ozone gas, the system should use a forced air process with a fan to push ozonated air into the exhaust connection. The connection should be engineered so that exhaust air does not back up into the work areas if the ozone fan system is not engaged.
We find that it is difficult to be precise in estimating the amount of ozone injected into the exhaust. Fortunately, excess ozone from the exhaust is not a concern since it quickly reverts to normal O2. But, if using a basic CFM (cubic feet per minute) of air flow, start with 500 mg/hr of ozone for each 1000 CFM. This is by no means a scientific measure, but rather a starting point. The test of effectiveness is the measurement of the VOC levels in the final exhaust. Tune the system by an effectiveness measurement by adding or reducing ozone to achieve the desired VOC levels.