First Full-Scale Activated Sludge Retrofit Using a Spirally-Wound MABR: Results and Model Evaluation

Start-up of the first full-scale, spirally-wound membrane aerated biofilm reactor (MABR) installation began in July 2019. The hybrid process is operated with both biofilm and suspended sludge to treat domestic wastewater. Retrofit of the MABR modules into the activated sludge anoxic zone, combined with a low dissolved oxygen (DO) control strategy in the aerobic zone, achieved increased treatment capacity and improved energy efficiency. The MABR nitrification rate (NR) ranged from 1.3 to 5.5 g/m2/day (10th -90th percentile), with the average being 3.1 g/m2/d. Rates of SND in the MABR zone were high as little nitrate accumulated in the MABR zone. Overall, the MABR zone contributed to 22% of the total ammonia removal and 27% of the total TIN removal experienced across the MABR train.