Pilot scale thermal treatment of pig slurry for the inactivation of animalvirus pathogens

This paper describes a pilot scale treatment plant that has been designed a nd built for the thermal inactivation in pig slurry of two viruses that inf ect pigs - African swine fever virus (ASFV) and swine vesicular disease vir us (SVDV). The plant treats pig slurry continuously at a rate of up to 100 litres/hour and functions by heating the slurry, maintaining at least 99.99 % of the slurry at the required temperature for a minimum period of 5 minut es, and then recovering the heat to raise the temperature of the incoming s lurry. Results obtained indicated that SVDV was inactivated in pig slurry t o below detectable levels with an alkaline pH (pH 7.5 to 8, as is usually t he case) at a temperature of between 50 and 55 degrees C. In acidified slur ry (pH 6.4), inactivation occurred between 55 and 60 degrees C. The differe nce in inactivation temperatures was probably due to the presence of free a mmonia in the unacidified slurry. ASFV was inactivated by operating the pla nt at a temperature of 53 degrees C at a pH of 8.