Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

Tao Jiang^1,2, Junguo He¹, Xiaonan Yang¹ ,Jianzheng Li¹

(1.School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;2.School of Energy and Civil Engineering, Harbin University of Commerce, Harbin 150028, China)



Abstract:

To elucidate the phosphorus removal and metabolism under various COD/P ratio, a sludge highly enriched in PAOs was used to investigate the impacts of COD/P in batch tests under different carbon supply conditions. Acetate, propionate and a mixture of acetate and propionate at a ratio of 3∶1 (COD basis) was used as carbon sources with the COD/P of 0,5，10 and 5.0 gCOD/gP, respectively. The minimum COD/P ratios for complete P removal were found to be 8.24 gCOD/gP for acetate, 11.40 gCOD/gP for propionate and 9.10 gCOD/gP for the 3∶1 mixture of acetate and propionate. Converted to a mass basis, all three cases had a very similar ratio of 7.7 gVFA/gP, which represented a useful guide for operation of EBPR plants to identify possible shortages inVFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD/P ratios suggested that,PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase, the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake, and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

Key words:  enhanced biological phosphorus removal  COD/P ratio  acetate  glycogen

DOI：10.11916/j.issn.1005-9113.2015.04.012

Clc Number:X703. 1

Fund: