A regenerative thermal oxidizer (RTO) is an industrial process for the treatment of exhaust air. The system uses a bed of ceramic

Ceramic

A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

 material to absorb heat from the exhaust gas and use the captured heat to preheat the incoming process gas stream.

These gas streams are usually produced by processes requiring ventilation, including paint booths, printing, and paper mill

Paper mill

A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags and other ingredients using a Fourdrinier machine or other type of paper machine.- History :...

s. Municipal waste treatment facilities such as mechanical biological treatment

Mechanical biological treatment

A mechanical biological treatment system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion...

 plants are required by law in Germany to incorporate these systems. Biological alternatives to this system include biofilter

Biofilter

Biofiltration is a pollution control technique using living material to capture and biologically degrade process pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and microbiotic oxidation of contaminants in air...

s and bioscrubbers.

They are suited to applications with low VOC

Volatile organic compound

Volatile organic compounds are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and...

 concentrations but high waste stream flow rates. This is due to their high thermal energy recovery. The basic operation of an RTO consists of passing a hot gas stream over a heat sink

Heat sink

A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...

 material in one direction and recovering that heat by passing a cold gas stream through that same heat sink material in an alternate cycle. They are used to destroy air toxics and VOCs that are discharged in industrial process exhausts.
There is a handful manufacturer of air pollution control systems for industrial use in Europe.
They produce highly efficient and cost-effective systems for the removal of:

• Volatile organic compounds (VOC)
• Hazardous air pollutants (HAP)
• Carbon monoxide
  Carbon monoxide
  Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
  
   (CO)
• Nitrogen oxides (NOx)
• Organic particulate matter (PM)

These companies have been involved in the development, design and planning of waste gas purification systems for a wide-range of industries: The CMM Group, located in De Pere, Wisconsin; WK Asia-Pacific Environmental Pte Ltd,located in German Center, Singapore.

The industries they currently serve are:

• Coal Mining Industry (VAM)
• Car manufacturing
• Packaging/printing
• Brick
• Paint shop
• Chemical
• Pharmaceutical
• Electrical
• Plastics
• Food processing
• Printing
• Foundries
• Semiconductor
• Metallurgical
• Sewage sludge treatment
• Metal recycling
• Wood

Different solutions to the waste gas problems of one of the mentioned industries are available:

• Catalytic oxidisers (CO)
• Regenerative thermal oxidisers (RTO)
• Regenerative catalytic oxidisers (RCO)
• Fixed bed adsorbers
• Rotary concentrator adsorbers
• Smoothing bed