Denitrification of high nitrate concentration wastewater using alternative carbon sources.
The use of different organic carbon sources in the denitrification of wastewater containing 2500 mg nitrates/L in a SBR was studied. Three alternative sources of carbon were tested: wastewater from a sweet factory, a residue from a soft drinks factory and a residue from a dairy plant. The first two are sugar-rich, whereas the third presents a high content in lactic acid. Maximum specific denitrification rates of between 42 and 48 mg NO(3)-N/g VSS h were obtained. The effluents were nitrate-free and very low COD concentrations were obtained in 4-6h reaction time, especially with the sugar-rich carbon sources. The values of the denitrifier net yield coefficient were higher than when using methanol (0.93-1.75 g VSS(formed)/g NO(x)-N(reduced)). The lowest value was obtained using the lactic acid-rich residue. The optimum COD/N ratios varied between 4.6 for the lactic acid-rich carbon source and 5.5-6.5 for the sugar-rich carbon sources.
Department of Chemical Engineering and Environmental Technology, University Institute of Industrial Technology of Asturias (IUTA), Higher Polytechnic School of Engineering, University of Oviedo, 33203 Gijón, Spain.
Y
Y
Fernández-Nava
E
E
Marañón
J
J
Soons
L
L
Castrillón
D001628:Beverages; D018533:Biomass; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry*; D003611:Dairy Products; D003612:Dairying; D005502:Food; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D007773:Lactates / Q000032:analysis; D008669:Metallurgy; D009566:Nitrates / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D013232:Steel; D013395:Sucrose / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D007773:Lactates; D009566:Nitrates; D014874:Water Pollutants, Chemical; D013232:Steel; D013395:Sucrose; D002244:Carbon; D010100:Oxygen