IEA publishes guide to using digestate as fertilizer., UK. 15 October 2010.

A guide highlighting the opportunities and challenges of using digestate
from AD plants as fertiliser has been published today (October 15) by the
International Energy Agency (IEA).

The document is designed to raise awareness amongst prospective digestate
producers and policy makers of the benefits of the technology, which it
says is experiencing 'renewed interest' across the world.

In particular, it points to the environmental benefit of using AD
'biofertiliser' in place of inorganic fertilisers made from fossil-fuels.

During anaerobic digestion, organic matter breaks down in the absence of
oxygen to produce biogas and digestate. The biogas, which consists largely
of methane (50-80%) and carbon dioxide (20-50%), can be used to generate
renewable energy while digestate can be used as a biofertiliser.

Sources of AD feedstock vary from municipal solid waste to sewage sludge
but it is estimated that over two billion tonnes of feedstock is
potentially available in the EU.

Looking in detail at the use of digestate as fertiliser, the report looks
at issues such as feedstock, nutrient management in digestate and
fertiliser management plans, impacts on the environment and controls and

The study concludes: "Biogas plants provide a fully sustainable and
integrated system for resource and environmental management that offer
governments a multipurpose technology option for fulfilling a cluster of
policy needs. For example, biogas can be used to displace fossil fuels
otherwise used for heating, electricity and transport. In addition,
digestate is an easy to use biofertiliser that can be used to replace
fossil fuels that otherwise would be used for fertiliser manufacture and
its transport around the world."

The full report, "Utilisation of digestate from biogas plants as
biofertiliser", can be found at:

Dr. Ann C. Wilkie                          Tel: (352)392-8699
Soil and Water Science Department          Fax: (352)392-7008
University of Florida-IFAS
P.O. Box 110960                         E-mail: [log in to unmask]
Gainesville, FL 32611-0960
Campus location: Environmental Microbiology Laboratory (Bldg. 246).
BioEnergy and Sustainable Technology Society