Evaluation of Sludge Treatments for Pathogen Reduction
The recycling to agricultural land is an important outlet for sewage sludge and other sludges but it must be controlled in order as to obtain agricultural benefit from the sludge whilst protecting human and animal health and the environment at large. Current practices in Europe are based on the requirements of the 1986 Directive on the use of sewage sludge in agriculture (86/278/EEC). Since that time new technologies have become available for sludge treatment, more pathogens associated with the food chain have been identified and the concerns of the public relating to acceptable risk have changed. This report identifies for a number of different types of sludges those pathogens that may present a risk to human, animal or plant health. It considers the factors in sludge treatment processes, particularly the newer processes, that influence lethal effects on pathogens, and makes recommendations for the parameters to be applied to these processes to produce treated sludges that present minimum risk.