Anoxic Granulation in USB Reactor with Anaerobic Granulated Sludge as an Inoculum

Environmental Security, 2011, Part 4, 295-302, DOI: 10.1007/978-94-007-0280-6_28
Katarina Galbova, Ivana Jonatova, Lenka Babjakova and Miloslav Drtil

Abstract

Anaerobic granulated biomass from high-rate anaerobic IC reactor was tested as a possible inoculum for anoxic granulation in post-denitrification USB reactor. The aim of the experiment was cultivate anoxic granules and to remove nitrates from wastewater after activated sludge process and secondary clarifier (20 mg l-1 NO3-N; with external organic carbon methanol; COD methanol: NO3-N = 6). Adaptation of anaerobic biomass to anoxic conditions and methanol lasted from 7 to 25 days. Anoxic granules with diameter of 3–5 mm and with excellent settling properties were cultivated by the anoxic granulation process. Maximum loadings of the USB reactor up to 22.4 kg COD m-3 d-1 and 3.2m3 m-2 h-1 proved exceptional properties of this kind of biomass. Compact structure and clear difference between core and cover of the granules, with dominant filamentous bacteria Sphaerotilus natans on the surface of the granules were detected by microscopic observation of the granules.

Keywords  inoculum for anoxic granulation - granular sludge - post-denitrification in USB reactor - microscopic observation