Performance of Denitrifying Phosphate Removal via Nitrite from Slaughterhouse Wastewater Treatment at Low Temperature

This study aims to investigate the effects of the organic loading rate (OLR) and the aeration rate on denitrifying phosphate removal (DPR) from slaughterhouse wastewater treated at a temperature of 11 degrees C. Three laboratory-scale intermittently aerated sequencing batch reactors (IASBRs) were set up and three OLRs and five aeration rates were employed in the study. The results indicated that efficient removals of nitrogen (N) and phosphorus (P) from DPR were achieved. Furthermore, the intermittent aeration pattern benefitted both the phosphorus-accumulating organisms (PAOs) and the denitrifying phosphorus-accumulating organisms (DPAOs) that accumulated at 11 degrees C. The ratio of P uptake in the aeration periods/P release in the non-aeration periods was in the range of 0.94-1.10 in the three stages. The relationship between the specific poly-beta-hydroxybutyrate (PHB) degradation rate (z), the specific P removal rate (x), and the specific total oxidized nitrogen(TON) reduction rate (y) can be fitted approximately as a plane (z = 1.3626x + 0.2882y - 0.6722, R-2 = 0.83).