Abstract

FERRARA DE GINER, Griselda  and  RAMIREZ, Armando. Influence of C/N ratio on the removal of nitrogen by using a combined system of sequencial batch reactors. Rev. Fac. Ing. UCV [online]. 2010, vol.25, n.4, pp.41-51. ISSN 0798-4065.

This work permitted to evaluate the influence of C/N ratio in a biological treatment system, integrated by two sequential batch reactors, RCSB and RCS. The RCSB permitted the nitrification of the synthetic residual liquid of weak composition and then the denitrification process took place in the RCS under three different conditions of volumetric fraction (α₁=0,50; α₂=0,20; α₃=0,00) used in order to balance the organic carbon content. The system was operated by 6 hours cycles to complete the nitrification (RCSB) and the denitrification (RCS) process. The C/N ratio in the liquid feeding the RCS was 18,7; 6,99 and 7,24 mg COD/mg NOx-N for the three α₁, α₂ and α₃ conditions. The nitrate formation in the RCSB was 91%, 95% and 95% for α₁, α₂ and α₃ respectively. The removal of the nitrate in the RCS reached 99%, 77% and 76% for α₁ α₂ and α₃ respectively, indicating a better denitrification process when organic carbon is supplied to the system. The nitrate concentration in the effluent of the RCS were 0,06; 3,6 and 3,9 mg/l for α₁ α₂ and α₃ respectively, which are much lower than the legal requirements in Venezuela.

Keywords : Bioreactors; Nitrification-denitrification; aerobic-anoxic biological process; sequential batch reactors; wastewater treatment.