Chemistry | Industrial Waste Water Recycling and Treatment in the Semiconductor Industry

The removal of dissolved ammonia from waste water in the semiconductor industry is performed by the reaction of ammonia with sulfuric acid to ammonium sulfate.

A process density measurement in combination with a measured pH value allows a real-time control of the waste water treatment process and guarantees the maintenance of the legislative limit.

Process chemicals used in the semiconductor industry are usually loaded with dissolved gases like NH₃, H₂S or NOₓ and have to be treated before released into the municipal waste water system.

For ammonia (NH₃) the waste water discharge standard has to be below a certain limit. The EPI Process for InGaN Chips pollutes waste water with ammonia to a great extent.

To avoid penalty fees, solved ammonia must be removed from the waste water. Due to the high solubility of NH₃ a removal cannot be done by using a sweep gas-vacuum combination as for CO₂ or O₂ removal. Modern water treatments work with the “Membrane Contact” technology.

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