Environmental Engineering Reference
In-Depth Information
13
Land application of digestate
ANNA CROLLA andCHRIS KINSLEY,
University of Guelph, Canada and
ELIZABETH PATTEY,
Agriculture and Agri-Food Canada (AAFC), Canada
DOI: 10.1533/9780857097415.2.302
Abstract: The anaerobic digestion process involves the breakdown of
organic matter to produce biogas, a mixture of CH
4
and CO
2
gases.
During this process, nutrients are transformed, volatile fatty acids are
consumed and pathogens reduced, leading to potential environmental
and agronomic benefits associated with the land application of digestate.
An extensive examination of the effects of land application of digestate
on NH
3
and N
2
O emissions, odour emissions, crop yield and migration
of NO
3
-N and bacteria to drainage tiles is presented. Experimental field
data collected by the authors supporting these environmental and
agronomic impacts are referenced throughout the chapter.
Key words: digestate, land application, GHG emissions, odours,
ammonia volatilization, nitrate leaching, pathogen migration.
13.1
Introduction
The potential of producing electricity and generating an additional financial
stream has driven a growing interest in the adoption of on-farm anaerobic
digesters. However, the environmental benefits associated with manure
anaerobic digestion, which include reduced greenhouse gas (GHG)
emissions, reduced odours, improved fertilizer nutrients and reduced
pathogens, can also help advance the uptake of farm digester technologies.
The anaerobic digestion process involves the breakdown of biodegradable
organic matter by a microbial population to produce a mixture of CH
4
and
CO
2
gases. This biogas can subsequently be used to produce both electricity
and heat. The capture and combustion of methane reduces its emission to
Search WWH ::
Custom Search