Problem No. 34: Reuse of off-spec waste

The waste water treatment section in a urea plant processes the water containing NH₃-CO₂ and urea from the vacuum system in the evaporation section. It delivers an almost NH₃-CO₂-urea-free purified process condensate that is suitable for reuse outside the urea plant. This process condensate can be discharged with a content of 1 ppm of urea and 1 ppm of ammonia. With such negligible values of pollutants, three targets are simultaneously realised which contribute to reducing the cost of urea: specific consumption of ammonia is decreased, environmental pollution is reduced and the possibility to reuse the process water is guaranteed for several technical purposes.