Affiliations: College of Municipal and Environmental Engineering,
Harbin Institute of Technology, Harbin 150008, China | College of Environment and Energy Engineering, Beijing
University of Technology, Beijing 100022, China | Hangzhou Huadong Gene-Technology Institute, Hangzhou
Abstract: 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.