Noxious weed seed deactivation by thermophilic anaerobic digestion, and the effects on fungal growth

Published in: Engineering Innovations for Global Sustainability: Proceedings of the 14th Latin American and Caribbean Conference for Engineering and Technology
Date of Conference: July 20-22, 2016
Location of Conference: San Jose, Costa Rica
Authors: Patrick J. O’Dell
César M Moreira
Pratap Pullammanappillil
Refereed Paper: #355

Abstract:

There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic digestion to treat sugar beet scrap materials has been proven as an effective alternative to landfilling. Byproducts of the anaerobic digestion process are liquid effluent and volume-reduced sludge. It is proposed that liquid effluent and sludge can be placed on arable lands. In order to return these byproducts, noxious weed seeds that may enter the digestion process must be eradicated in the process. This study was undertaken to determine if five species of noxious weeds seeds would be destroyed by anaerobic digestion. Small batch anaerobic digesters were made to study its effect on five weed species. The digestion lasted for 10 days and was performed at 55 ºC. Five additional samples were used to determine the effects of warm water on the seeds. In addition, five dry containers with dry seeds were incubated to determine the effects of dry heat. Results showed that both anaerobic digestion leachate and warm water caused seed destruction for the all seeds compared to dry heat treatment or no treatment. A secondary observation showed that fungal growth was inhibited by anaerobic digestion.