| The effects of influent nitrate concentration and its adding modes on denitrifying phosphorus removal in a wastewater with low carbon(COD=200 mg/L) using a sequencing batch moving bed biofilm reactor(SBMBBR) operated under anaerobic-anoxic conditions was investigated. After the domestication, the percentage of denitrifying phosphorus removing bacteria(DPB) in all phosphorus removing bacteria(PB) increased from 15.7% to 71.3%, indicating that DPB was enriched. Concentration of the influent nitrate had a significant effect on the treatment. At the influent nitrate concentration of 30 mg/L, i.e., C/N=6.7∶1, COD, PO3-4-P and NO-3-N removal increased to 97.8%, 82.0% and 81.2%, respectively, showing an efficient treatment under this low carbon. When the influent nitrate was less or more(20 and 40 mg/L), phosphorous uptake observed was insufficient in the anoxic stage, and poly-R-hydroxybutyrate(PHB) increased from 2.2 mg/g MLSS in the initial anaerobic stage to 5.1 mg/g MLSS and 3.5 mg/g MLSS, respectively, affecting phosphorous release in the next period. Adding nitrate in one time, two times or continuous mode had little effect on the denitrifying phosphorus removal, but affected the removal rate in the initial anoxic stage. |
