Wastewater coming out from industries need to be treated by
physical and chemical methods to remove the toxic and harmful chemicals. As per
the environment regulation standards, the effluent such as urea, ammonia and
carbon dioxide can be treated by hydrolysis and desorption technique. By this technique,
the treated water reused as boiler feed water. Cooling water mixed with this
treated water to maintain water balance in process industry.
Urea and ammonia hydrolysed
in a reactor where high pressure steam is feed from the bottom and leave out from
the top of the reactor section. The nitrogen and carbon compounds dissolved in
the wastewater stripped out. High-pressure steam will carry the wastewater
chemical components to low pressure column. Water condensed at low-pressure
section and urea, ammonia and carbon dioxide removed as vapours from the top of
the low-pressure column. Treated water
contains no traces of ammonia, carbon dioxide or urea. This type of system is
preferred in ammonia and urea production industries.
Another technique follows a counter current flow system in
hydrolysis. Thermal application in hydrolysis will make ammonia and urea
removal more effective but consumes high energy. However, by use of
pervaporation technique added to thermal hydrolysis system large amount heat distributed
without loss. The condensers used in condensing the vapours of treated water,
vapours that contain the impurities avoided, and the heat duty is taken care by
the pervaporation system.
