Effect of COD/N ratio on simultaneous removal of nutrients and COD from synthetic high strength waste water under anoxic conditions

Abstract

Simultaneous removal of nitrate, PO4 and COD from synthetic wastewater containing high substrate and low COD/N ratio, under anoxic conditions has been attempted in the current study. Maximum removal of nitrate (98%), PO4 (96%) and COD (93%) was achieved at a COD/N ratio of 1.62. PO4 removal rate ranged between 77.6, 88.7, 90.5, 95.9, 93.1 and 93.2% at a COD/N ratio of 0.36, 0.97, 1.36, 1.62, 4.06 and 6.37 respectively. Thus PO4 removal rate was more or less impervious to varying concentration of nitrate and carbon load in the system. pH measurements during the course of reaction, gave new insights into the denitrification and PO4 uptake processes. Statistical analysis (ANOVA) further determined a significant variance between removal of PO4, nitrate and COD with respect to time of reaction as well as in different experimental set up.