Application of biofertiliser to pasture – Risk management for disease exposure

[Y2M8 MorVet Ltd report]

Introduction:  The use of biowaste as feedstock for anaerobic digesters produces energy and biofertiliser, while reducing global warming. This system is used widely around the world, and the Bioenergy Association is promoting its increased use in New Zealand. However animal and human pathogens are typically present in the feedstock. Hazards to animal and human health from these pathogens are identified, and the effect of procedures specified in the Bioenergy Association “Guidelines for the production of digestate biofertiliser for application to land” (2025) and alternative procedures are described, including the evidence to support the conclusions.

If the entire amount of either feedstock or preferably biodigestate is heated to at least 700C for one hour or more, then risk attached to all organisms of concern other than spore-forming Gram positive bacteria will be effectively controlled, while the risk attached to spore-forming Gram positive bacteria can be effectively managed.

This report has been commissioned to provide advice on the nature of any hazards involved in the process, and the adequacy of risk management strategies used in biofertiliser application.

Useful links and reports

• Characterisation of NZ digestate for contamination risk and safe use