ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Comparison of anoxic granulation in USB reactors with various inocula

Katarína Galbová, Petra Pagáčová, Miloslav Drtil, and Ivana Jonatová

Department of Environmental Engineering, Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology, Slovak Technical University, Radlinského 9, Bratislava, 812 37, Slovak Republic

E-mail: katarina.galbova@stuba.sk

Received: 27 April 2009  Revised: 30 November 2009  Accepted: 4 December 2009

Abstract: Anoxic granulation process with four different inocula was monitored in a laboratory post-denitrification up-flow sludge bed (USB) reactor. Wastewater containing 20 mg L⁻¹ NO₃-N and methanol as an organic carbon source was used. Gradual increase of mass volumetric loading (B _v) and hydraulic loading (γ) resulted in spontaneous granulation of anoxic biomass both from flocculant activated sludge and from anaerobic granulated sludge. With flocculant activated sludge as the inoculum, anoxic granules sedimentation properties and maximum loadings of the USB reactor depended on the sludge volume index (SVI) of the inoculum. B _v,max achieved in the USB reactor with flocculant inoculum from a municipal wastewater treatment plant (SVI = 208 mL g⁻¹) was only 4.2 kg of COD per m³ per day and 0.7 kg of NO₃-N per m³ per day. B _v,max using flocculant inoculum from an industrial wastewater treatment plant (SVI = 170 mL g⁻¹) was 8.1 kg of COD per m³ per day and 1.35 kg of NO₃-N per m³ per day. With anaerobic granulated inoculum (SVI range 8–11 mL g⁻¹), markedly higher loadings in the USB reactor and lower SVI values of anoxic granulated biomass were achieved. Values of B _v,max were in the range of 16.1–22.4 kg of COD per m³ per day and of 2.7–3.7 kg of NO₃-N per m³ per day (depending on the inoculum and the granulation procedure). It was proved that anaerobic granulated sludge is not just an inoculum, it is also a carrier for new denitrification biomass.

Keywords: anoxic granulation - post-denitrification - USB reactor - inoculum

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0119-2

Chemical Papers 64 (2) 132–138 (2010)