NITROGEN REMOVAL IN AN ACTIVATED SLUDGE SYSTEM WITHOUT PRIMARY CLARIFICATION
Full scale tests with nitrogen removal have been performed at the Klagshamn wastewater treatment plant in Malmö, Sweden. Characterization of the wastewater and earlier tests at the plant have shown that the organic material in the primary effluent was limiting the overall nitrogen removal. The organic material in the raw wastewater measured as BOD7 was reduced with about 50 % by primary clarification. By utilizing the organic material in the raw wastewater the carbon to nitrogen ratio can be increased from 2.3 to about 4 g BOD7/g Ntot. Consequently, tests were performed in a pre-denitrification system where the primary clarifiers were taken out of operation. Simulation models were used for the test planning and for the data evaluation. The tests were monitored intensively by chemical characterization and sludge activity measurements. “Complete abstract not presented.”