| Energy
Making a market for digestate
By Charlotte Morton, Chief Executive of the Anaerobic Digestion & Bioresources Association (ADBA).
n last month’s
issue of FMN I
discussed the
need for
policymakers to
recognise the
many non-energy benefits of
anaerobic digestion (AD), which to
date have not been linked to
financial support mechanisms.
Most people are aware that AD
plants convert agricultural wastes
and energy crops into renewable
heat and electricity and clean
transport fuel, the generation and
production of which is supported
by the Renewable Heat Incentive,
the Feed-In Tariff, and the
Renewable Transport Fuel
Obligation respectively. There is,
however, another vital co-product
of the AD process that is often
forgotten.
That co-product is digestate, a
stable, nutrient-rich substance that
can be used for a range of
products and purposes: most
usefully as a nutrient-rich
biofertiliser, but also as feedstock
for ethanol production and in low-
grade building materials such as
fibreboard.
When used as a biofertiliser on
I
farmland, digestate improves soil
health by maintaining pH and soil
fertility, increasing organic matter,
improving soil structure, and
reducing water demand, soil
20 | Farming Monthly | June 2018
degradation, and run-off. This is
important as soil damage, risk of
run-off, drainflow, run-through to
groundwater, and erosion all affect
growing conditions.
The spreading of digestate back
to farmland also helps provide the
essential crop requirements of
nitrogen, phosphorous, potassium
and trace elements. Use of
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