Pilot study for the potential application of a shortcut nitrification and denitrification process in landfill leachate treatment with MBR

An advanced nitrogen removal pilot study was performed in China's Xia Ping Landfill Leachate Treatment Plant to undertake shortcut nitrification and denitrification with the Membrane Bio-reactor (MBR) process. It was found that the MBR process used 25% less of the oxygen and 40% less of the external carbon sources, compared to the conventional nitrification and denitrification process. The key feature of the MBR process is that it provides an environment more favorable for ammonia oxidation bacterium (AOB) than for nitrite oxidation bacterium (NOB) through controlling loading, pH, temperature, dissolved oxygen concentration (DO), and NH₃ inhibition. Optimum operating condition was examined through continuous running of the pilot MBR, and it was found that a minimum HRT of 4.3 days and maximum ammonia loading of 0.6 kg N-NH ₄⁺ m³.d with pH 7-8.5, temperature 25-30°C, and DO at 2 mg/L is favorable to AOB. Kinetic study was conducted to identify the characteristic of the microorganisms in the system. Measured K_s and μ_A,max of MBR sludge was 19.65 mg NH₄-N/L (Temperature 25°C, pH 8.5) and 0.26 d^-1, respectively. © IWA Publishing 2006.