The optical method of De Ley et al. (1970) for determining DNA/DNA homologies was reexamined. Several parameters such as incubation temperature, incubation time, DNA concentration and DNA fragment length were checked and the optimal conditions established. Hybridization data of several anaerobic Gram-positive cocci were compared with values obtained by the membrane filter technique. The agreeme...

Using a previously developed filter adsorption technique, the inactivation of a human rotavirus, a coxsackievirus B5, and a bovine parvovirus was monitored during sludge treatment processes. During conventional anaerobic mesophilic digestion at 35 to 36 degrees C, only minor inactivation of all three viruses occurred. The k' values measured were 0.314 log10 unit/day for rotavirus, 0.475 log10 u...