1. #adrdforum @adbioresources
COLIN KEYSE
PROJECT MANAGER OF ORGANIC CONVERSIONS, CWM HARRY
IFBB – WIDENING THE RANGE OF
FEEDSTOCK TO IMPROVE THE
OPERATING VIABILITY OF
ANAEROBIC DIGESTER
INSTALLATIONS

2. What else can we put in it?
IFBB - widening the
range of feedstock to
improve the
operating viability of
Anaerobic Digester
installations

3. Getting the max out of your feedstock
• Conventional thinking about
improving AD efficiency has been
about sequential process step
improvements.
• Pre-treatment to optimise availability
of convertible substances: maceration,
pressure or ultrasonic cell disruption,
autoclaving etc.
• Optimisation of biological and
engineered digestion conditions
• Post-treatment of digestate to
minimise costs and odour problems.

4. Monetising other outputs has been of secondary
importance so far
• Since RHI, some interest has arisen in
utilising surplus heat from the CHP –
but location and planning issues still
trump the proximity of a heat client.
• Digestate disposal has been a
problem to be alleviated – despite
several WRAP-funded trials. The lack
of a ready market and inconsistency
of ‘product’ has discouraged major
investment in this area to date.
• Largest potential market is to replace
artificial NPK fertilizers – but
digestate products have not yet
persuaded conservative farming
market of benefits.

5. Adding a parallel process
• If you don’t want to add
a different feedstock to
the AD process, could a
dual-stream design be
beneficial?
• Could the addition of
different feedstock
generate additional
products and revenue
giving an overall net
gain?

6. The IFBB process – what it does
• Can utilise ‘marginal
biomass’ where accessible
energy content is less than
optimal
• Silaging phase allows for a
biostatic feedstock buffer .
• Pre-separation of
cellulosic solids creates an
additional revenue stream
and simplifies digestate
post-treatment.

7. Grass silage already used in on-farm AD
• Bank Farm trials with
Montgomeryshire Wildlife Trust
and Powys CC 2006
• AILE/CG22 Brittany trials June
2013
• Net energy yield = 2.6x that
used to harvest and transport.
• Similar results using roadside
verge cuttings taken around
mid-late June
• What if, for environmental or
operational reasons, vegetation
cannot be harvested until later ?

8. What is the effect of ‘Mashing’?
0.0 0.2 0.4 0.6 0.8 1.0
Chlorine
Calcium
Magnesium
Potassium
Sulphur
Dry matter
Mass flow into the press cake
Mass flow into the press fluid
Nitrogen

9. Adding IFBB alongside FWAD
• Utilises wider range of material
that can be pre-processed and
stored ready for use.
• Mash and pressing stage extracts
available sugars and starches into
liquor
• Liquor can be added to food
waste / energy crops instead of
just water in main digester
• Fibrous material separated prior
to digestion - can utilise waste
heat from CHP to dry it.
• ‘Press Cake’ can be blended with
woodchip to create storable
biomass briquette worth £100-
£200 /T depending on local
market

10. What additional capital costs are there?
• Vegetation harvesting and ensiling –
can use agricultural machinery – can
be hired-in
• Feedstock storage – could be offsite -
rented
• Mash stage – tanks, heat exchangers,
agitaters etc.
• Screw press dewaterer (£35-250k)
• Press cake drying stage – high temp-
short duration/ambient temp (solar) –
long duration
• Briquetting press and briquette
storage.

11. Energy Balance shows use for surplus heat from
FWAD CHP

12. Cwm Harry at Moelyci –
Farm Scale stand-alone IFBB pilot
• Moelyci – 390 acre traditional Welsh Hill
farm .
• 600-1000T pa DM feedstock available.
• Plenty of room for solar assisted presscake
drying
• On-site Biomass boiler and heat main for
buildings
• Integration with parallel technologies
planned ( e.g. Micro IVC with heat
recovery and solar collectors)
• Pilot supply-chain co-operative planned.
• Integrated exemplar site to show it can be
done
• Increase range of feedstocks that can be
used
• Diversify and grow income streams from
the activity
• More efficient utilisation of heat, water
and nutrients – on-site if possible
• Make smaller, more localised plants
affordable , adaptable and viable
• Keep revenue capture within local
economy
• Provide a replicable business model for
communities and clusters of small farms
and SME’s

13. For further information on:
• Cwm Harry Land Trust
• COMBINE Interreg IVb project and partners
• PROGRASS – the European network
• IFBB – the process and it’s development
• Socio-economic challenge for upland rural
Wales
• colink@cwmharry.org.uk 01686 626234
• www.cwmharry.org.uk

14. Diolch yn Fawr iawn
Thank you very much