Industrial Waste Water Recycling and Treatment in the Semiconductor Industry

Relevant for the Semiconductor Industry

Solved gases in waste water

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

For ammonia the waste water discharge standard has to be below a certain limit.
To avoid penalty fees solved ammonia must be taken out of the waste water. Because of 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 via the Membrane Contact technology.

2NH3 + H2SO4 = (NH4)2SO4

The Membrane Contact technology for NH3 removal works by adding a sulphuric acid. The low pH value in combination of sulphate ions in the waste water react immediately with the ammonia (equation above). So the ammonium is taken out of the waste water by a good efficiency. Adding chemicals won't pollute the waste water additionally.


Process density sensor L-Dens 7400 Version Tantalum

Tantalum is used because of its resistance to ammonium, ammonium sulphate and especially sulphuric acid. The highly accurate density sensors can be used in a wide range of applications. They continuously monitor the product quality of liquids online during production. A pH meter is used for additional control.


  • Quick visibility if still enough ammonia can be taken out of the waste water
  • Avoidance of human and sampling mistakes

Learn more about the L-Dens 7000 Density Sensors Series


Do you have any questions?

Contact Anton Paar directly: process[at]


Specifications L-Dens 7400 Version Tantalum:

Measuring range: 3000 kg/m3
Process temp. range: -40 to +125 °C
Ambient temp. range: -40 to +65 °C
Process pressure: max. 50 bar
Typical repeatability: ±0.02 kg/m3

Other relevant instruments

  • Pico 3000 (RC)