This study presents the shortcut nitrification in a membrane aerated bioreactor (MABR) treating high strength nitrogen waste stream. The utilization of MABR has advantages of bidirectional control of oxygen (O2) and substrate, highly energy efficient O2 transfer capacity and reduced stripping of noxious gases (NH3, NO2, and N2O). The MABR system was continuously operated for over 2 years during which the membrane bioreactor treated anaerobic digester effluent. The digested effluent has an average carbon and organic nitrogen concentrations of ~450 mg-C/L and 900 mg-N/L, respectively. The MABR processed a variety of nitrite oxidizing inhibition factors and their impacts on nitrite built-up. These parameters include pH, free ammonia (FA), free nitrous acid (FNA), dissolved oxygen, gas flowrate, and mean cell residence time. Over the 2 years of operation, the MABR was able to reduce the organic carbon by 60-80% and transformed 40-75 % of total nitrogen to NOx, over a range of retention times (2 to 4.5 days. The ratio of NO2- to NOX in the effluent varied from (~0 to 90%) across various reactor operational conditions. At shorter retention times, nitrite oxidation was reduced compared to longer retention times and led to nitrite built-up. At the test point with the highest nitrite accumulation rate, FNA and FA concentrations were ~2 mg-N/l and 0.5 mg-N/l respectively. Overall, the test points presenting the lower pH values and higher retention time led to the lowest nitritation performance in the MABR system.
This presentation is available to AMTA Members only.
Speaker
- Maryam Salehi
Company
- Texas Tech University
Event
- AMTA/AWWA Membrane Technology Conference, West Palm Beach, FL
Session
- AMTA/AWWA Membrane Technology Conference
Date
- 07/20/21
Media
Keywords
- Nitritation, MABR, Wastewater
Reference
- 9710-DP2671