HIGH-TEMPERATURE AMMONIA STRIPPING AND RECOVERY FROM PROCESS LIQUID WASTES

The feasibility of a process for ammonia removal and recovery from hig h temperature waste waters is assessed. NH3 is stripped away in a pack ed column by means of air which is continuously looped to a further ab sorption unit. Here ammonia is dissolved in an acid solution which is sent to a crystalliser for (NH4)(2)SO4 production (a fertiliser). The performance of the process was studied at varying the temperature leve l, the flow rate to be treated, the ammonia inlet and outlet concentra tions, and the packing type used in the stripping and absorption colum ns. The unit treatment cost appears to be competitive compared to alte rnative technologies, especially for high ammonia inlet concentrations and operating temperatures. Moreover, no escape of ammonia to the atm osphere is assured, contrary to simple stripping units.