Survival of seeds from perennial biomass species during commercial‐scale anaerobic digestion |
| |
| Authors: | K A Baute D E Robinson L L Van Eerd M Edson P H Sikkema B H Gilroyed |
| |
| Affiliation: | 1. School of Environmental Sciences, University of Guelph Ridgetown Campus, Ridgetown, Ontario, Canada;2. Department of Plant Agriculture, University of Guelph Ridgetown Campus, Ridgetown, Ontario, Canada |
| |
| Abstract: | Tall perennial grass species can be utilised as bioenergy feedstocks, but some are considered invasive species. Using biomass from such species as feedstocks for anaerobic digestion (AD) may introduce the risk of disseminating viable seeds onto agricultural lands during digestate application. To evaluate this risk, we investigated the survival rates of perennial grass seeds obtained from biomass species during AD. After removal from the digester, seeds were germinated and stained with tetrazolium chloride to determine viability. During three experimental runs, batches of 100 seeds from four species were exposed to 0, 2, 6, 12, 24, 48, 72 and 168 h of mesophilic (38°C) AD within a commercial‐scale digester. Seed viability of Phalaris arundinacea, Phragmites australis, Panicum virgatum and Solanum lycopersicum was reduced by 95% (LT95) after 29, 52, 98 and 105 h of AD respectively. Commercial digesters that utilise perennial grasses as a feedstock typically have retention times ranging from 240 to 1480 h, which greatly exceeds the LT95 values found in this study. Anaerobic digestion resulted in the rapid death of seeds in all species tested, suggesting unwanted dissemination of perennial grass species via digestate application to agricultural land is unlikely. |
| |
| Keywords: | biogas
Panicum virgatum
Phalaris arundinacea
Phragmites australis
seed viability |
|
|
