Removal of Nitrogen and Organic Matter in a Radial-Flow Aerobic-Anoxic Immobilized Biomass Reactor Used in the Posttreatment of Anaerobically Treated Effluent

Author： Fazolo Ajadir Foresti Eugenio Zaiat Marcelo

Publisher： Humana Press, Inc

ISSN： 0273-2289

Source： Applied Biochemistry and Biotechnology, Vol.142, Iss.1, 2007-07, pp. : 44-51

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

This work reports on the removal of organic matter and nitrogen in a radial-flow aerobic-anoxic immobilized biomass (RAIB) reactor fed with domestic sewage pretreated in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor. Polyurethane foam was used as support material for biomass attachment in both reactors. In batch experiments, a first-order kinetic model with residual concentration represented the organic matter removal rate, whereas nitrogen conversion followed a pseudo-first-order reaction in series model, with kinetic constants k ₁ (ammonium to nitrite) and k ₂ (nitrite to nitrate) of 0.25 and 6.62 h⁻¹, respectively. The RAIB reactor was operated in continuous-flow mode and changes in the airflow rate and hydraulic retention time were found to interfere in the apparent kinetic constants to the nitritation (k ₁) and nitratation (k ₂). Nitrification and denitrification were achieved in the partially aerated RAIB reactor operating with hydraulic retention times of 3.3 h and 2.7 h in the aerobic and anoxic zones, respectively. Ethanol was added in the anoxic zone of the reactor to promote denitrification. The effluent flow of the RAIB reactor presented a COD of 52 mg l⁻¹, and concentrations of 2 mg $$ {\text{N}} - {\text{NH}}^{ + }_{4} {\text{ l}}^{{ - 1}} $$ , 1.24 mg $$ {\text{N}} - {\text{NO}}^{ - }_{2} {\text{ l}}^{{ - 1}} $$ and 3.46 mg $$ {\text{N}} - {\text{NO}}^{ - }_{3} {\text{ l}}^{{ - 1}} $$ .