[Performance of nitrogen and phosphorus removal from municipal wastewater of different C/N ratios using intelligent controlled systems sequencing batch biofilm reactor ( SBBR)].

ABSTRACT

The laboratory-scale experiments were conducted to treat synthetic municipal wastewater at different C/N ratios, using a developed intelligent controller sequencing batch biofilm reactor (SBBR), which formed alternative aerobic-anoxic environment. The performance of nitrogen and phosphorus removal was investigated under different conditions (T = 25 degrees C +/- 1 degrees C, V(aeration) = 150 L/h, COD = 300 mg/L, TP = 5 mg/L, TN = 30 mg/L, t(operation) = 15 d; TN = 60 mg/L, t(operation) = 20 d; TN = 90 mg/L, t(operation) = 20 d). The average removal efficiency of COD reaches 85.2%, 91.1% and 97.7%, the average removal efficiency of TP achieves 94.1%, 95.9%, 96.7% ,the average removal efficiency of NH4(+) -N reaches 95.8%, 99.2%, 80.0%, and the average removal efficiency of TN are 90.7%, 81.1%, 58.3%, respectively. With the decrease of C/N ratios, the removal efficiency of N decreases significantly, while the removal efficiency of COD and TP increase slightly. In intelligent controlled SBBR, simultaneous nitrification and denitrification and shortened simultaneous nitrification and denitrification occur, meanwhile, the denitrification of the system strengthens with the increasing of C/N ratios. After the influent finished, intelligent controlled SBBR starts to operate in aerobic-anoxic environment. The efficiency of phosphorus removal is high, moreover, the theory of phosphorus removal is different from the conventional theory of release anaerobic and uptake aerobic phosphorus.