This paper focuses on a new granulation study area where a mixture of suspended anaerobic and aerobics cultures was used as seed. Mixed suspended anaerobic and aerobic cultures exposed to alternating anaerobic/microaerobic/aerobic conditions developed granulates up to 2.5 mm in size. The granules developed displayed both oxygen uptake (3.83-8.75 mg dissolved oxygen g-1 volatile suspended solids h-1) and methanogenic activities (7.5 cm3 CH4 d-1) comparable to those of aerobic and anaerobic control cultures, respectively. Oxygen doses of 60, 100 and 120% of the total chemical oxygen demand added (23, 38 and 45 cm3 ) and ethanol (among ethanol, glucose, acetic acid, and glucose+acetic acid) resulted in the largest and the most stable granules.
- Combined systems