Denitrification of wastewater containing high nitrate and calcium concentrations

• Published in: Bioresource technology Vol. 99; no. 17; pp. 7976 - 7981
• Main Authors: Fernández-Nava, Y., Marañón, E., Soons, J., Castrillón, L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2008; [New York, NY]: Elsevier Ltd; Elsevier
• Subjects: Applied sciences; Batch Reactors; Biodegradation, Environmental; Biological and medical sciences; Calcium; Calcium - analysis; Calcium - pharmacology; Calcium Compounds - pharmacology; Denitrification; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; High nitrate wastewater; Kinetics; Nitrates - analysis; Nitrogen - metabolism; Oxides - pharmacology; Oxygen; Pollution; SBR; Stainless Steel; Volatilization; Waste Disposal, Fluid; Wastewaters; Water Purification; Water treatment and pollution; Denitrification; SBR; High nitrate wastewater; Calcium; Nitrates; Waste water
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2008.03.048

The removal of nitrate from rinse wastewater generated in the stainless steel manufacturing process by denitrification in a sequential batch reactor (SBR) was studied. Two different inocula from wastewater treatment plants were tested. The use of an inoculum previously acclimated to high nitrate concentrations led to complete denitrification in 6 h (denitrification rate: 22.8 mg NO 3 - -N / g VSS h ), using methanol as carbon source for a COD/N ratio of 4 and for a content of calcium in the wastewater of 150 mg/L. Higher calcium concentrations led to a decrease in the biomass growth rate and in the denitrification rate. The optimum COD/N ratio was found to be 3.4, achieving 98% nitrate removal in 7 h at a maximum rate of 30.4 mg NO 3 - -N / g VSS h and very low residual COD in the effluent.