Regenerative thermal oxidizers and thermal/catalytic oxidizers convert pollutant-laden process exhaust streams into CO2and water, providing solutions for abating volatile organic compounds, hazardous air pollutants and/or odors. Both types of units achieve greater than 99 percent destruction/removal efficiency levels. Regenerative thermal oxidizers systems operate at 1,500oF (816oC). Thermal and catalytic designs use precious-metal catalysts for operation from 600 to 800oF (316 to 427oC), depending on the process. There are alternate operating modes in the thermal catalytic system, so a user can first operate in the catalytic mode to save on fuel, then make an online switch to thermal operation instead of replacing deactivated catalyst.