This paper analyses the performance of the anaerobic selector (A/O process) in a full-scale activated sludge process receiving mostly industrial sewage discharge (>60%) in Singapore. In addition to the sludge settleability, enhanced biological phosphorus removal (EBPR) was studied. The sludge volume index (SVI) reduced from 200 to 80 ml g−1 and foaming was suppressed significantly, indicating the effectiveness of the anaerobic selector in improving sludge settleability. The phosphorus removal efficiency was 66%, and 7.5 mg HAc-COD was consumed per mg PO3−4-P removed. In the anaerobic compartment, 31% of the SCOD and 73% of the acetic acid in the settled sewage were removed with PO3−4-P release of 14.1 mg PO3−4-P l −1. The linear correlation between PO3−4-P release in the anaerobic compartment and PO3−4-P uptake in the aerobic compartment indicates that there is about 0.8 mg PO3−4-P release in the anaerobic compartment per mg PO3−4-P uptake in the aerobic compartment. The fates of volatile fatty acids (VFAs) and its short chain acids (SCAs) in the process were studied and discussed.
Analysis of phosphorus removal and anaerobic selector performance in a full-scale activated sludge process in Singapore
Y.S. Cao, C.M. Ang, K.S. Raajeevan, A.K. Kiran, K.C. Lai, S.W. Ng, I. Zulkifli, Y.L. Wah; Analysis of phosphorus removal and anaerobic selector performance in a full-scale activated sludge process in Singapore. Water Sci Technol 1 October 2006; 54 (8): 237–246. doi: https://doi.org/10.2166/wst.2006.706
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