AD within the Fiberight process
Peter Speller, Dhivya Puri25-01-19
How are these business models related?
Where is the value?
Apps Bolt-ons
Energy
Plastics & materials
Value added Metals & glass
Chemicals & fuels
Material Recovery Platform
Homogenous
materials
Technology
Pulping Separation RecoveryPaper / card
Rigid plastics
Metals
Flexible plastic packaging
Food waste
GlassAD
Environmental issues
Plastic waste
Circular economy
Recycling rates
• Incremental increases• Plateauing recycling rates• Something needs to change
Waste industry solution
• Increase segregation
• Increase incineration capacity
‘Solves’ waste problem
‘Recycles’ material into energy
Low materials recovery
Only ‘part’ of the solution
Recycling challenge / Fiberight solution
‘10 ‘11 ‘12 ‘13 ‘14 ‘15 ‘19 ‘25 ‘30 ‘35
80
60
40
20
Perc
enta
ge (%
)
EU Targets
55
60
65
> 80
UK recycling rates
GHG savings
• Pilot Plant (kg scale) – Southampton, UK
• Demonstration plant (15,000 tpa) – Virginia, USA
• Commercial plant (150,000 tpa) Maine, USA (2019)Scale through development platform (reduces costs)
Commerc ia l development
Commercia l p lant
https://app.frame.io/f/ab95056d-7049-4f47-a608-9e306c4e6e84
• Demonstration facility was key to understanding materials flows and for mechanical development of process
• The plant is run in campaigns – no continuous production of foodwaste laden water– Difficult/impossible to assess how continuous AD will behave– Not able to see the effects of water recycle in the system
• UK R&D base established to study continuous AD in more detail– Initial academic studies with University of Southampton– Now running pilot plant with small scale model of commercial reactor
R&D
The importance of AD
• Anaerobic digestion is used to treat the foodwaste fraction of MSW
• High Rate AD no digestate sludge produced only a liquid effluent
• Effluent recycled back into start of process
• Water based MSW separation process so high efficiency AD is key to successful operation
• Key revenue or energy stream (depending on subsidies)
Fiberight R&D pilot plant
• Established our own integrated R&D facility with 70L pilot AD reactor which is a model replica of commercial implementation
Pilot studies
• Running for 6 months with effluent recycling
• Good biogas yields, with the specific methane potential near theoretical yields
0.000.100.200.300.400.500.600.700.800.901.00
SMP
(m3
CH4/
kg
TCO
D re
mov
ed)
SMP (SCOD)
• Higher than theoretical yields achieve due to breakdown of suspended solids in system (TCOD)
Pilot studies
Positives
• No bed flotation
• No degranulation
• Not seeing inhibition due to effluent recirculation in system
• Suspended solids not negatively affecting biogas yield
Negatives
• Starting to see suspended solids build up through system due to incomplete breakdown
Pilot studies
• Flocculation studies to determine whether suspended solids could be removed without affecting sCOD yield
• Flocculant selected from a series of tests which determined most affective flocculate for use
Tests: 1) mild shaking of flocculant with washwater
2) vigorous mixing of flocculant with a larger volume of washwaterResult
Control
(No
flocculant)
100ppm
(mild
shaking)
200ppm
(mild
shaking)
300ppm
(mild
shaking)
Control
(No flocculant)
300ppm
(150 L)
(Vigorous mixing)
COD
(% of
control)
100 82 75 72 100 22Significant COD loss
Pilot studies
Other options
• Secondary CSTR for suspended solids
0
0.05
0.1
0.15
0.2
0.25
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48
CH4
(L/g
VS
fed/
day)
Time (days)
CH4 production
Relatively low biogas yields per g VS in CSTR
Also tried pre-treatment with enzymes to increase solubilisation and improve yields
Pilot studies
Other options
• Secondary CSTR for suspended solids
• Pre-treatment can help to improve biogas yields and stabilise reactor
• Also testing use of solids for VFA production (PhD @ Southampton)
0
0.05
0.1
0.15
0.2
0.25
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48
CH4
(L/g
VS
fed/
day)
Time (days)
CH4 production Enzyme pre-treatment
No pre-treatment
Pilot studies
• Optimal AD performance is vital for the efficient running of the Fiberight process • clean effluent necessary
• Pilot studies give key insights into how full scale system should run (ideally)
• R&D required to optimise performance & increase value of outputs
Fiberight [email protected]