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 ConfidentialDhivya.Puri@fiberight.co.uk