Research on Ultrasonic Stripping-A/DAT-LAT Technics for the Treatment of Azodicarbonamide Production Wastewater

Considering the high ammonia nitrogen concentration of azodicarbonamide (ADC) foaming agent wastewater, the combined process route of the ultrasonic stripping pretreatment with A/DAT-IAT shortcut nitrification-denitrification technology was studied. Simulating test showed that the removal efficiency of ammonia nitrogen in the wastewater increased with the increase of pH, the reaction temperature and stripping time. Under the condition that ultrasonic power 100 W, gas-liquid ratio for 500:1, the optimum experiment condition was set as follows: pH 11, reaction temperature for 303 K and the ultrasonic stripping time for 80 minutes. Under the optimum conditions, it was founded that the ammonia nitrogen removal efficiency of ADC foaming agent wastewater can reach to 90%. The biochemistry experiments results proclaimed that A/DAT-IAT shortcut nitrification-denitrification biological denitrification craft can be realized at low DO concentration (1.0 mg/L). The average NH₄ ⁺-N concentration in the raw wastewater was 280.1 mg/L, the average effluent NH₄ ⁺-N concentration is 12.3 mg/L, the removal efficiency is beyond 95%; If the reactive system maintains low DO concentration for a long period of time, the shortcut nitrification could carried out and nitrosation rate can peak up to more than 90%.