Ammonia removal (NH3) out of wastewater in an NH3 stripper absorber combination
Wastewater (industrial as well as municipal waste water) often contains high concentrations of ammonia. To remove the ammonia out of the wastewater, the air stripping of ammonia-laden water is a proven technology. The ammonia or NH3 is first stripped from the wastewater in the stripping tower. The equipment used for this stripping process is similar to that of the gas scrubbing technology : an NH3 stripping tower is a packed column (with internals and packing inside) similar to those used for chemical gas scrubbing. The preheated ammonia-laden water enters the stripper on top, a counterflow gas stream comes in from the bottom of the NH3 stripper. NaOH is added to obtain a correct pH value, which will allow the ammonia to be dissociated or stripped from the water. The treated water will be collected at the bottom ot the stripper; the now ammonia-laden gasses leave the striptower at the top, for futher treatment in the NH3 absorber.
In the absorber the ammonia-laden gasses are treated with sulphuric acid, to absorb the ammonia. The outcoming gasses are recirculated to save on energy costs.
The end product of this technology will be a concentrated salt solution (ca. 25% ammonia sulfate solution – often used as fertilizer). This way, the technology is entirely fitting in the cradle-to-cradle philosophy.
Ammonia (NH3) stripper absorber combination technology : advantages
- lower operating cost
- no steam required