Properties of Anaerobic Granular Sludge in a Thermophilic Expanded Granular Sludge Bed Reactor

Abstract:

This study investigates the properties of thermophilic anaerobic granular sludge in an expanded granular sludge bed for cassava ethanol wastewater treatment.Experimental results show that the average chemical oxygen demand (COD) removal efficiency and the average gas production are 86.7% and 15.1 L·d-1,respectively,with the influent organic loading rate (OLR) being maintained at 15.0 kg·m-3·d-1.Moreover,the OLR can be increased up to 24.0 kg·m-3·d-1 with the average COD removal efficiency and the average gas production being 88.5% and 33.9 L·d-1,respectively.With the increase of operation time,the granular ratio of anaerobic sludge increases and the granular sludge with diameter greater than 2.00 mm is 32%.The organic components in granular sludge are mainly C,H and N,and the inorganic components were mainly Si,P,Ca and Fe.The bacillus bacteria are predominant in the acclimation thermophilic sludge and the inner core of sludge is probably composed by the compound of calcium phosphate or calcium carbonate.

Key words:thermophilic temperature; expanded granular sludge bed reactor; cassava ethanol wastewater; granular sludge