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.
Advantages of the ammonia (NH3) stripper absorber
combination technology
-
lower operating cost
-
no steam required
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