METHOD OF NITROGEN AND PHOSPHORUS CONTENT REDUCTION DURING WASTE WATERS TREATMENT

摘要

The solution concerns a method of reducing contents of nitrogen and phosphorus in wastewater treatment. The sludge water is after anaerobic stabilizing of crude sludge alkalized by calcium to pH value of 10.5 to 12.4. The sludge is separated from it by sedimentation. Then the sludge water is pre-heated and introduced in rectification, where the content of ammoniac is reduced. The sludge water with reduced contents of ammoniac transfers heat to the sludge water introduced in rectification and returns into the aerobic treatment stage. The condensation heat from rectification is used for heating up sludge in anaerobic stabilization. The product from rectification is ammonia liquor, which gets into contact with biogas in absorber. This results in achieving the concentrated solution of technical ammonium carbonate, utilizable as a nitrogen fertilizer.