Bioreactor consisting of pressurized aeration and dissolved air flotation for domestic wastewater treatment

• Published in: Separation and purification technology 2014-12, Vol.138, p.186-190
• Main Authors: Zhang, Qidian, Liu, Shujie, Yang, Chunping, Chen, Fuming, Lu, Songlin
• Format: Article
• Language: English
• Subjects: Aeration; Bioreactor; Bioreactors; Dissolution; Dissolved air flotation; Domestic; Flotation; Nitrification; Nitrogen removal; Optimization; Pressurized aeration; Purification; Wastewater treatment
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2014.10.024

•A reactor including pressurized aeration and dissolved air flotation is developed.•The reactor has the advantages of both the processes.•The effects of various parameters on removal performance are examined.•The bioreactor is effective for domestic wastewater treatment. In this study, the effects of air pressure, dissolved oxygen (DO) concentration and carbon–nitrogen (C/N) ratio on the treatment efficiency of a pilot-scale bioreactor consisted of pressurized aeration and dissolved air flotation (PA–DAF) were evaluated for domestic wastewater treatment. Results show that SS removal increased with an increased air pressure in the range of 0.10–0.50MPa, and COD removal peaked at 86% for 0.40MPa. At DO concentrations ranging from 0.5 to 5.5mg/L, NH4+–N removal increased to up to 99% as DO concentration was increased, while a peak for TN removal was observed due to nitrification and denitrification. NH4+–N removal decreased while the C/N ratio was increased from 3 to 12, and a peak TN in removal was also observed. The optimal NH4+–N and TN removal efficiency achieved were 99% and 78% when the DO concentration was 2.5mg/L and 3.5mg/L, respectively. The NH4+–N removal efficiency was close to 100% at a C/N ratio of 3, and the maximal TN removal efficiency was 80% at a C/N ratio of 5. These results demonstrated the effectiveness of the bioreactor for domestic wastewater treatment.