ROLE OF FILTER MEDIA IN AN ANAEROBIC FIXED-BED REACTOR

The relationship between the filter media and the behaviour of anaerob ic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher th an those attached to the filter media. On the other hand, the number o f attached methanogenic bacteria was more than ten times as higher tha n that of suspended ones. The numbers of suspended and deposited acido genic and methanogenic and methanogenic bacteria in the reactor operat ed at an HRT of 3 hours were almost the same as those in the reactor o perated at an HRT of 48 hours. Accumulation of attached bacteria was p romoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was hig her than that in the closely packed reactor was lower than that in the closely packed reactor.