Mechanical biological treatment (MBT) is a combination of mechanical separation and biological treatment processes like composting or anaerobic digestion. MBT facilities in the UK produce a variety of outputs like recyclables, compost, solid recovered fuel, and digestate. However, the changing composition of waste and uncertainty around markets for MBT outputs like compost pose challenges. Flexible MBT designs are more expensive but can help address these composition risks.

1. MECHANICAL BIOLOGICAL TREATMENT
Solution or Hype?
Dr. Adam Read – Practice Director
Waste Management & Resource Efficiency, AEA
AWMA 2012
A world leading
19th – 22nd June energy and climate
change consultancy
San Antonio, Texas

2. Overview ….. In 20 minutes ….
+ Personal Welcome
+ UK Waste Situation
- Drivers, Legislation, Targets….
+ What is Mechanical Biological Treatment (MBT)?
+ The role of MBT?
+ MBT development in UK
+ MBT Composts and Digestates
+ Waste Composition changes?
+ Conclusions …
2

3. A personal welcome
+ Adam Read
- Practice Director @ AEA
- 17 years of operational expertise in waste technology appraisal,
design and procurement
- Staff of 75 plus consultants (UK and US)
- Leading MBT procurement for a number of UK authorities
- Specialise in waste infrastructure siting and community liaison
+ Role on the project
- Project Director and lead policy advisor to the Essex Waste
Partnership, North London Waste Authority & West Sussex County
+ Acknowledgements
- Andy Godley as lead author and UK leading specialist on MBT
technologies, their application and monitoring
- Chris Hoy as co-author and lead modeller 3

4. My sponsors …. www.aeat.co.uk

5. Our US sponsors
+ We are here exhibiting with ERG
- we acquired them in 2010
+ Come and see us on Booth #118
- ERG and AEA Technology Group
+ Franklin Associates (ERG division)
- extensive experience in all aspects of
solid waste management (over 30 years
of practice)
- integrated solid waste master plans
- full life cycle analyses of solid waste
- waste stream evaluations for local,
regional, state, and national agencies
5

6. The UK Waste situation
6

7. The EU Landfill Directive
+ EU Landfill Directive – mitigating landfill’s environmental
impacts
- BMW reductions required to mitigate fugitive CH4 emissions
- Pre-treatment of landfilled materials
- Landfill waste acceptance criteria (WACs)
- Landfill design, operation, completion and closure requirements
+ BMW includes commercial and industrial wastes and
municipal waste streams
+ BMW Landfill targets for the UK
- 75% of 1995 level by 2010
- 50% of 1995 level by 2013
- 35% of 1995 level by 2020
+ Significant driver for innovation in technology solutions
7

8. The Need For Change in the UK (MSW)
60
50
Millions tonnes per annum
40 Non-biodegradable
Municipal Waste
30
20 Biodegradable Municipal Waste
Requiring Diversion
10
Biodegradable Municipal
Waste Allowed to Landfill
0
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

9. Government ‘Waste’ Objective
Annual reduction in GHG emissions of 9.3 million
tonnes of CO2 equivalent per year
Equivalent to annual use of 3 million cars!
Closure of most of the 8,000 licensed facilities
Procure, design & build a suite of new treatment
facilities!!
Need to identify bankable solutions / technologies

10. The UK Recycling Agenda
+ UK Policy
- Derived from EU Directives
- Encourage Recycling and Recovery including
EfW
- Discourage Landfill
+ UK Recycling targets
- Revised Waste Framework Directive
(2008/98/EC)
- 50% by 2020
- Set nationally at 60% in Scotland, Wales and
Northern Ireland
- Currently recycling 42% (2010-11)
- Need to increase diversion
o @ curbside or @ treatment facility ? 10

11. The Energy situation in the UK
+ Commitment to CO2 Reduction
+ Commitment to Renewable Energy
+ Ageing Nuclear Capacity
+ High gas and oil prices (security risks)
+ Dwindling home production of oil and gas
+ Rising population ~20m by 2070
+ Equates to a potential Energy Crisis
- Extracting energy from waste seen to be a positive contribution!
- But EfW (capped at 20% of MSW)
- Looking at expansion of Biogas & Solid Recovered Fuel production
11

12. The growth of AD solutions
+ AD has historically been used in sewage treatment
+ Use of biogas is a major bonus
+ Now recognised as an option for generating ‘value’
- recognised and actively promoted
o UK Government AD Road Map & Action Plan
o ROCs incentive for electricity generation (x2)
o Renewable Heat Incentives (feed in tariffs)
+ Feedstocks
- Food waste & farm wastes
- Residual wastes (yes but poorer quality)
+ Commonly being linked with fuel preparation technologies
- Like MBT!
12

13. Revised Waste Framework Directive
+ 2008/98/EC
+ Waste Hierarchy
+ Recycling Targets – 50% by 2020
+ End of waste status – CLO from MBT not applicable
- Drives greater quality in collection & processing …. 13

14. The ‘residual waste’ debate
+ EfW v MBT – only realistic options currently out there!
+ EfW
- Incineration has bad public image and planning permission difficult
- Involves combustion of all waste with limited recovery
- Combustion is single use
- Only exploits energy content of waste
- Low cost but irreversible MBT is gaining
popularity in the UK!
+ MBT
- Greener image and planning is easier
- High recycling and exploits carbon chemical value as well as energy
- High flexibility to offer best value
- Can preserve other nutrients in CLO (N, P, S)
- High cost but more flexible 14

15. Scale of MBT application in Europe
+ MBT has provided a substantial contribution to EU waste
management practices since 1990
+ 330 major MBT facilities in EU
- mainly Spain, Italy, Germany
+ 450 major MBT facilities in EU by 2016 (expected)
+ UK
- About 20 major facilities (<50,000 tpa) are operational
- More than 20 planned or under construction
- Combined capacity ~ 4,000,000 tpa
- Selected as more politically acceptable and reduces the
need for a thermal facility by 50%
15

16. What is MBT?
16

17. MBT is ….
+ Combination of Mechanical separation and Biological
Treatment (composting and/or anaerobic digestion)
+ Processes may include multiple steps in any order and
produce a variety of outputs dependent on the MBT design
+ Possible outputs:
- Metal recyclables
- Glass recyclables
- Plastic recyclables
- Compost like output (CLO)
- Biogas energy
- Solid fuel (SRF or RDF)
- Biostabilised waste
- Residues
17

18. MBT solutions
18

19. MBT – design can hide all process types
19

20. More MBT
20

21. MBT outputs
21

22. The role of MBT?
22

23. Role of MBT
+ Landfill and Recycling Targets are being achieved through
- Composting garden waste
- Collection recyclables (e.g. plastics, glass, metals) as
source segregated or co-mingled and separated in MRF
- Promotion of food waste collections and AD
+ This leaves residual “black bag waste” ~40 - 50% of MSW
+ Simple choice
- Thermal Treatment (Energy from Waste) or MBT
+ MBT often seen as more acceptable to public
- Not a burner & reduces tonnage going to thermal
treatment
- No chimney! 23

24. MBT solutions in the UK
24

25. UK MBT Development (options)
+ MBT with Biodrying and SRF Production
- several established and in construction/procurement
+ MBT with RDF and AD
- many in procurement
+ MBT with Biostabilisation
- a few in construction and procurement
+ MBT with rapid composting and recyclate production
- a few in operation
+ MBT with AD and recyclate recovery
- one in construction
+ MBT with RDF and composting
- None
25

26. Biodrying MBT
CO2, Moisture
Biological step: Mechanical SRF (has BMW)
Short composting step: Refining
2-4 weeks. SRF and
Drying limits recyclate Metals
degradation recovery Glass/Aggregates
Residue (has BMW)
O2 Optional Re-wetting
and composting Biostabilised Residue
residue
26

27. MBT with RDF and AD
RDF (has raw BMW) Biogas/energy
Mechanical
step: Refining Biological step:
RDF and Anaerobic
recyclate Digestion Digestate
recovery (partially biostabilised)
Metals
Glass/Aggregates
Plastics
27

28. MBT for Bio-stabilisation
CO2, Moisture
Mechanical step: Metals
Biological step:
Extended Refining and Glass/Aggregates
composting 6-12 recyclate Plastics
weeks recovery Paper
CLO
Residue
O2
28

29. MBT for Rapid composting and recyclate
CO2, Moisture
Metals
Biological step: Mechanical
Glass/Aggregates
Rapid high rate step: Refining
and recyclate Plastics
composting 1-2
weeks recovery Paper
Partially biostabilised
CLO
Residues
O2
29

30. MBT with AD and recyclate
Biogas/energy
Biological step:
Wet Mechanical
Anaerobic Digestate
step:
Digestion (partially biostabilised)
(Paper included in AD feed
as well as food waste)
Metals
Glass/Aggregates
Plastics
30

31. MBT with RDF and Composting
RDF (has raw BMW) CO2, Moisture
Mechanical Metals
step: Refining Biological step: Glass/Aggregates
RDF and Composting CLO
recyclate 4-8 weeks.
recovery Biostabilised Residue
Metals
O2
Plastics
31

32. MBT compost and digestate
32

33. MBT compost like outputs (CLO)
+ Potential MBT outputs
- CLO has significant potential for recycling to land/land reclamation (but
an uncertain market)
- Many MBT designs could produce CLO if market was available
- Stabilised compost CLO also counted
+ Previously in UK this could contribute to recycling targets
under NI192 (recently abolished)
- New definition of recycling is coming (CLO wont count)
+ Significant tonnage of CLO produced in UK but rationale no
longer pertinent
- Could see a switch in MBT design ….
- Less CLO production and increase in MBT with AD because of the energy
agenda….
33

34. MBT compost like outputs (CLO)
+ Revised Waste Framework Directive (2008/98/EC)
- Likely that CLO will not attain “End of Waste Status” as from mixed source
o CLO then would not count towards recycling
o Recent selling point for MBT with AD of digestate recycling invalid
o What happens to digestate from existing MBT with AD facilities?
o Potential increase in source segregation of organic waste to obtain
end of waste status of digestate, e.g. food waste removal for separate
AD
- Impact on UK MBT facilities?
o Those with AD? – loss of good food waste feedstock
o Those with composting? – loss of feedstock for biostabilisation and
biodrying
- Takes the B out of MBT and MBT concept redundant
o Potential concern that significant investment in MBT infrastructure in
UK to be undermined! 34

35. The global recession
+ Has also had a significant impact on UK waste management
+ Reduced need / feedstock for residual treatment
- 5% reduction in waste arisings year on year (2008 – 2011)
- Some authorities have reported 10% reductions in some years
+ End markets for SRF are under threat
- Cement kilns are taking less waste derived feedstock
- Postponement of developments with integrated SRF & CHP
- Postponement of merchant SRF-EfW developments
- Increasing competition for SRF outlets (insufficient SRF utilising capacity)
+ Solutions:
- Procure your own SRF using facility (as in West Sussex)
- Export SRF - possible but stringent consent condition (Shanks to Germany)
- Landfill the SRF!! (seems at odds with the rationale for MBT!) 35

36. Export the SRF
+ Export Consent required from Environment Agency
+ High quality of SRF required
- must be free of hazardous contamination
- but definition of contamination is not specific
+ Any export batch may be inspected
+ High risk of adverse publicity and fines if batch rejected
+ Also subject to economic recession
+ UK currently exports 300,000 tpa
- Over 1 M tpa is licensed (Holland, Germany, Denmark etc.)
+ Recent permits for Sita to export to Rotterdam / Amsterdam
- To fill up the spare capacity in their EfW facilities
- Lose of UK resources and energy potential – seems nuts! 36

37. The Essex Waste Partnership
+ Residual Waste Treatment for ~380,000 tpa
+ Preferred technology MBT – No Waste Incineration Policy!
+ Objectives:-
- Meet BMW diversion targets & minimise total waste landfilled
- Maximise recovery of recyclables
- Exploit SRF if markets become available (none currently)
+ MBT biostabilisation system that can switch to produce SRF
- Maximise decomposition of biodegradable waste (LOI & biogas reduction)
- Maximises moisture loss
- Maximises and flexible recyclables – metals, plastics, aggregates, CLO
- Flexible to switch operation to produce SRF if markets available
+ Acceptable redundancy of equipment in different operational
modes….. A significant investment but retains flexibility! 37

38. Essex County @ procurement
+ Predicted contract value of £2.5 billion over 25 years (PFI)
+ Demonstrating savings of £300m (compared to do nothing)
+ Carbon benefits of 2.4 million tonnes of CO2 saved
+ In built switching capability believed to cost an additional
£80 million
+ Real costs will be known in July 2012 @ preferred bidder
38

39. What might it look like?
39

40. Waste Composition Changes?
40

41. Waste Composition Changes
+ Residual waste composition is variable and will change!
- Changes in waste generation (efficient use of products)
o less waste
- Changes in consumer products & packaging
o changing type, size, density etc.
- Changes in source segregation
o removal of materials from feedstock (food)
+ MBT flexibility comes at a cost!
- High level of waste composition detail needed for MBT design
o content and type of components such as plastic film dense plastic, PVC
plastic, food waste, metals – to set targets and design equipment
- High flexibility to meet all composition change risk
o complex and costly plant
- Low flexibility to meet all composition change risk
o simpler plant, lower cost, but at risk of being made redundant 41

42. Composition risks
+ MBT plant failure?
- Examples known where waste composition has fallen outside MBT
design parameters before the plant has become operational
o From design & contract award to operations can take 3 or 4 years
- Build in redundancy of equipment to accommodate changes in waste
composition or retrofit equipment to keep pace with changes in waste
composition!
o Expensive
+ EfW plant failure?
- Waste composition is less important
o Only concern is calorific value
- Less susceptible to residual waste composition changes
- Lower risk for investors & decision-makers ….
42

43. MBT Procurement & composition risk
+ Lengthy discussion on waste composition impacts
- Balance of cost vs. flexibility
- Need good data @ outset
- Need to model impacts of changes and the flexibility of proposed
solutions
+ Transfer waste composition risk to technology provider
- Must treat waste provided effectively whatever its composition
- Comes @ a cost
+ Control of feedstock quality for residual waste stream
- Facility must deal effectively with residual waste whatever its
composition
43

44. Conclusions
44

45. Conclusions
+ MBT often selected as more acceptable to public (and
politicians) than EfW
+ MBT is playing a significant and growing contribution to UK
waste management
+ Various designs of MBT exist with increasing emphasis on
MBT with AD (fits UK Renewable Agenda)
+ MBT derived composts and digestates do not qualify as
recycling – undermining some of the earlier plans!
+ MBT is sensitive to changes in waste composition
+ MBT flexibility comes at a cost – but needs to be addressed
@ outset
+ Potential that many UK plants will prove costly to remain
functional to keep pace with future waste situation 45

46. Lessons for the US
+ Switching technologies needs careful
analysis
+ Solving 1 priority may create problems
elsewhere in the system
+ Look @ joining up the agendas (energy,
resources, waste etc.)
+ Don’t choose MBT to boost recycling or
deliver quality composts!
+ Fuel preparation is a valid role for MBT
prior to EfW, Cement Kilns, Advanced
Thermal Solutions
+ Learn from the UK’s experiences ….
46

48. Thank you!
48

49. Come and see us …. Booth #118
Adam Read Shelly Schneider
Practice Director - AEA Franklin Associates (ERG)
Waste Management & Resource Waste Management & Resource
Efficiency Efficiency
cell: 0044 7968 707 239 tel: 913-800-8276
email: adam.read@aeat.co.uk email: Shelly.Schneider@erg.com
web: www.aeat.co.uk web: www.aeat.co.uk