ISSN: 0366-6352 (print version) ISSN: 1336-9075 (electronic version) Springer's Journal No. 11696

Granulation of activated sludge in a laboratory upflow sludge blanket reactor

Petra Pagáčová, Miloslav Drtil, and Katarína Galbová

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

E-mail: petra.pagacova@stuba.sk

Received: 31 March 2008  Revised: 24 June 2008  Accepted: 2 July 2008

Abstract: The creation of anoxic granulated biomass has been monitored in a laboratory USB (Upflow Sludge Blanket) reactor with the volume of 3.6 L. The objective of this research was to verify the possibilities of post-denitrification of residual NO₃-N concentrations in treated wastewater (denitrification of 10-20 mg L⁻¹ NO₃-N) and to determine the maximum hydraulic and mass loading of the granulated biomass reactor. G-phase from biodiesel production and methanol were both tested as external organic denitrification substrates. The ratio of the organic substrate COD to NO₃-N was 6. Only methanol was proven as a suitable organic substrate for this kind of reactor. However, the biomass adaptation to the substrate took over a week. The cultivation of anoxic granulated biomass was reached at hydraulic loading of over 0.35 m h⁻¹. The size of granules was smaller when compared with results found and described in literary reports (granules up to 1 mm); however, settling properties were excellent and denitrification was deemed suitable for the USB reactor. Sludge volume indexes of granules ranged from 35-50 mL g⁻¹ and settling rates reached 11 m h⁻¹. Maximum hydraulic and mass loadings in the USB reactor were 0.95 m3 m⁻² h⁻¹ and 6.6 kg m⁻³ d⁻¹. At higher loading levels, a wash-out of the biomass occurred.

Keywords: denitrification - anoxic granulation - granulated biomass - USB reactor

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0092-1

Chemical Papers 63 (2) 125–130 (2009)