Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge.
Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated. Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrifying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration, it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.
Wang
Ya-yi
YY
College of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150008, China. yayiwang@163.com
Peng
Yong-zhen
YZ
Wang
Shu-ying
SY
Pan
Mian-li
ML
D001421:Bacteria, Anaerobic / Q000502:physiology; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D010758:Phosphorus / Q000302:isolation & purification* / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014865:Waste Disposal, Fluid
D009566:Nitrates; D012722:Sewage; D010758:Phosphorus; D002244:Carbon