Anaerobic digestion (AD) holds the potential to mitigate GHGs from livestock farms by producing renewable energy and being a sustainable manure management system. Particulary, we focus on the reduction of emissions from dairy farms, which are responsible for 4% of total anthropogenic emissions.
AD converts organic material in cattle waste, into biogas (mixture of methane and carbon dioxide) and digestate (solid residue). The methane in biogas can be used for heat and/or electricity production, offsetting the use of fossil fuels. Carbon dioxide released after combustion of methane from biogas is considered to be carbon neutral as it belongs to a fast atmospheric cycle.
The digestate produced by AD can be used in farms as fertilizer. This can partly replace the use of inorganic fertilizer with high embodied energy. Additionally, the digestate emits less methane and nitrous oxide than fresh manure stored or applied on fields.
Database of methane yields for AD of dairy cattle manure
Methane yield is the most common metric utilised for reporting the performance of and AD system. It is an indicator of the amount of methane produced per mass unit of volatile solid in the untreated organic waste. Much research has quantified the methane yield of dairy cattle manure, however, a systematic and quantifiable review of the literature is needed. As a first step of this meta-analysis approach, a database of the methane yields from selected research peer-reviewed articles has been compiled.
To access the database of methane yields of dairy cattle manure, please click here. An automatic reply will be sent to you with the password to download the database here. Please select the "read-only" option when opening.
Database of GHG emission mitigation using AD
The carbon footprint of dairy farms is a life-cycle indicator that can be found widely in the academic literature. However, the combination of multiple (and sometimes contrasting) results has not been yet examined. Therefore, our research has focused in bringing together studiest to make robust evidence of the changes in emissions that a dairy farm can experience when implementing AD. We are approaching this by utilizing meta-analysis methodology.
To carry out our meta-analysis, we have created a novel database that collects the relevant information in the literature. A blog on the first version of this database can be found here. To access the database of greenhouse gas emission from dairy farms implementing anaerobic digestion, please click here. An automatic reply will be sent to you with the password to download the database. Please select the "read-only" option when opening.