Module 2 – Alternative Waste Treatment Technologies (AWT ) Dr Darren Perrin

1. Module 2 – Alternative Waste Treatment Technologies (AWT)Dr Darren Perrin

2. Module Outline • The aim / learning outcome of this module is to provide an overview on the range of technologies that are available for the treatment of mixed waste streams and a brief understanding of the factors which influence the deliverability and operation of different alternative waste treatment technologies (AWTs). • What are AWT’s and their role in a strategic framework • The impact of collection strategies on AWT feedstock • Factors influencing the deliverability of AWT • Clear strategy in procuring an AWT

3. Module 2 – AWT – the technologies Dr Darren Perrin

4. What is AWT? • What does the definition include? • Track record • Europe, America and Japan - Successful operational experience and knowledge principally within Europe, America and Japan, but examples across the globe. • Australia / New Zealand - Mixed performance, recent focus primarily on organics • What do they do ? • Mechanical Sorting / Separation / Pre-treatment • Biological Processes • Physiochemical Processes • Thermal Processes • No ‘one stop’ solution suitable for all • Lack of information makes it difficult to compare fairly

5. The role of the AWT to manage waste • 100% kerbside recycling? - At what cost? • We will always have residual (general mixed) waste • We will always have a need for landfill • Challenge is to: • Understand how much residual waste • Understand what the residual waste consists of • Design and implement appropriate technology to manage the waste in a manner which meets the local and regional strategic objectives in accordance with the waste hierarchy • Have a common understanding on what the process will and won’t do and manage expectations accordingly.

6. The Technologies • Biological Technologies: • Composting (in-vessel) • Anaerobic digestion) • Mechanical and Biological treatment (MBT) • Sort first / bio-treat second • Bio-treat first / sort second (bio drying) • Mechanical Heat Treatment (MHT) / Autoclaving • Advanced Thermal Treatment (ATT) • Gasification • Pyrolysis • Plasma gasification • Mass burn incineration (energy from waste) • Grate combustion • Fluidized bed combustion

7. AWT within the waste hierarchy AWT AWT AWT AWT

8. AWT - Not the answer, but part of an integrated solution....... Avoid AWT Minimise Recycle

9. Examples of The Technologies

10. The Waste Management System

11. Biological technologies • Aerobic Digestion - in the presence of “air” • Anaerobic Digestion- in the absence of “air” Biodrying Windrow In Vessel Composting

12. Composting • Composting is the microbial decomposition of organic material in the presence of oxygen to produce compost. There are two main types of composting: • Open windrow is most commonly used in Australia for green garden waste • In-vessel composting is common in Europe and increasingly being taken up in Australia for green garden and food waste

13. Anaerobic Digestion • Anaerobic digestion is the microbial decomposition of organic matter into biogas (approximately 60% methane and 40% carbon dioxide) and digestate (solid or liquid) in an oxygen depleted environment. • Two main types: Wet (>80% moisture) and Dry (50 to 80% moisture) • Typical waste feedstock include source segregated organics from household and commercial premises, biosolids, manure and farm slurries and purpose grown crops.

14. Mechanical Biological Treatment • Mechanical Biological Treatment is a generic term for an integration of several processes and technologies commonly found in different waste management facilities such as MRFs and biological treatment facilities. • Using mechanical and biological processes to separate / prepare mixed waste into usable fractions and / or render it more ‘stable’ for deposit into landfill. • They commonly use composting or anaerobic digestion for treatment of mixed general waste to separate / prepare this into usable fractions and / or render it more ‘stable’ for deposit into landfill.

15. Mechanical and Biological Treatment Inputs Mixed Waste Outputs Recyclables CLO RDF Issues Not an end process in its own right Outputs need a market Bio-drying process does not necessarily stabilise material Benefits Can maximise recycling Relatively proven European track record Treatment of waste with “no stack”

16. Mechanical Heat Treatment • Mechanical Heat Treatment is use of steam based thermal treatment, with or without pressure, in conjunction with mechanical processing for clinical and mixed general waste. • There are two main types of facility that use mechanical heat treatment: • Autoclaving – a batch steam processing in a metal vessel under the action of pressure • Rotary kiln - continuous heat treatment in a rotating vessel, not under pressure

17. Mechanical Heat Treatment Inputs Mixed Waste Input Outputs Clean Dry Recyclables Fibre Flock Issues Energy intensive Need output for biodegradable fraction. Benefits Relatively lower capital cost Simple technology Cleans metals and glass inputs Sanitises waste (pressure cooking) Separation of waste easier after processing

18. Advanced Thermal Treatment (ATT) • Advanced Thermal Treatment (ATT) is an umbrella term that is used to categorise waste treatment technologies that utilise thermal processes to treat mixed general waste that are different to incineration. • Primarily those that employ pyrolysis and/or gasification to process mixed general waste and also exclude full combustion thermal processes (i.e. incineration).

19. Advanced Thermal Treatment (ATT) • Gasification • Thermal and chemical conversion of carbon based material within mixed general waste into mainly gaseous outputs. Temperatures are in the range of 800-1100°C with air as the gasification agent and up to about 1500°C with oxygen. Overall gasification processes are exothermal, i.e. producing heat • Pyrolysis • The thermal degradation of organic materials within mixed general waste MSW in absence of oxygen. Temperatures are typically around 300-800°C. Overall the process is endothermic, i.e., energy is required for the pyrolysis process to proceed.

20. ATT – how it works

21. Advanced Thermal Treatment Outputs Gas (Syngas) Oil and tar Ash and Metals Inputs Prefers single / pre-treated waste streams Issues A variety of operational risks due to history Differentiation from incineration “true” gasification and “staged” gasification Not all systems have energy efficiency benefits over incineration High capital cost Benefits Produces renewable energy in the form of syngas Reduces waste volume, destroys BMW Potential benefits of small scale or integrated facilities Smaller scale than mass burn (niche applications) Potential for smaller Air Pollution Control equipment

22. Incineration • Incineration involves combustion of mixed general, clinical and hazardous waste with sufficient quantities of air in temperatures often in excess of 850°C. The main types are: • Fixed grate • Moving grate • Fluidised bed • Rotary kiln

23. Inputs Mixed or Single Waste Input Incineration • Outputs • Heat used to produce electricity (and/or a local user) • Bottom ash can be recycled (20 – 30%) • Metals for recycling (3 -5 %) • Air pollution control residues (4 - 7%) Issues Poor public perception Potentially large land takeCapital intensive Commercially viable approx. 100k tpa + Benefits Proven technology with long track record Reduces waste volumes Established markets for outputs

24. Levels of Air in Combustion Processes

25. Module 2 – AWT – the Challenges Dr Darren Perrin

26. Challenges • Perceptions • Meeting expectations and risk transfer • Assessing commercial deliverability • Affordability

27. Meeting expectations and risk transfer What goes in .... must come out! – poor quality input leads to poor quality output

28. Exercise – AWT Issues

29. What is MIXED Residual (GENERAL) Waste ? • Different composition • Different materials which can be recycled / composted • Materials which can’t be recycled or composted • Energy Value • Gross Calorific Value (GCV) • Moisture Content • Net Calorific Value (NCV) • Ash generation potential • Proportion of Biomass

30. The conundrum – Competition for Material ? Waste Material Waste Collection Schemes Alternative Waste Treatment Technology

31. Exercise • Naughts and Crosses

32. The conundrum – Different Authorities Waste Collection Schemes Alternative Waste Treatment Technology Waste Collection Schemes Waste Collection Schemes Waste Collection Schemes

33. The conundrum – Different Schemes Waste Collection Schemes Scheme Design Materials Targeted Contamination Presentation Separation Efficiency Area Characteristics Composition Waste Generated Demographics

34. The Challenge....... ? ? ? ? Alternative Waste Treatment Technology ? ? ? ?

35. Waste Composition

36. Waste Composition Can vary

37. Refuse Organic Material Flows Available Recycling Self Haul

38. Organic General Waste System interaction Recycling Sort and Transfer AWT MHT MRF Bulking ATT MBT Biological Treatment EFW AD IVC Windrow Power Landfill Product

39. 8.1% Newspapers 7.9% Glass bottles and Jars 3.4% Drink and Food Cans Organic Refuse Bring Sites Recycling

40. Collection Systems Changes • Change number of households offered a service • Change number of households who use the service • Change how often they use the service • Change what materials are targeted • Change how effectively the material is captured i.e. placed in the correct container

41. Refuse Recycling Wk 1 = 2 / 5 = 40% Set Out Rate Wk 2 = 2 / 5 = 40% Set Out Rate Wk 3 = 3 / 5 = 60% Set Out Rate = 4 / 5 = 80% Participation Rate

42. Recognition, Capture and DIVERSION RATE 10 10 10 10 = Total = Total 10 30 20 0% Recognition Rate 50% Recognition Rate 0% Recognition Rate 25% Capture Rate 17% Diversion Rate 50% Recognition Rate 10 10 5 5 10 5 5 15 15 5 5

43. There is material remaining in the General Waste container

44. Waste Feedstock Exercise (In groups) • Assumption: No kerbside recyclables collection system in place, 200,000 tpa of household general waste generated; • Question: If ‘you’ introduced a kerbside recycling scheme in your council area, approximately how many tonnes of residual waste would you have left to treat in an mixed waste AWT facility?

45. Not All Materials are targeted

46. Sensitivity of Targeted Materials Waste Generation 100,000 tonnes Material Available (Composition 5%) 5,000 tonnes Coverage (90%) 4,500 tonnes X Participation (70%) 3,150 tonnes X 1,890 tonnes Recognition (60%)

47. Waste Feedstock Exercise (In groups) • Assumption: No kerbside recyclables collection system in place, 200,000 tpa of household general waste generated; • Question: - If ‘you’ introduced a kerbside recycling scheme in your council area, approximately how many tonnes of residual waste would you have left to treat in an mixed waste AWT facility? • Now • Assume • 50,000 available in composition • Coverage of 90% • Participation 70% • Recognition 60% Change recognition ? Change participation ?

48. Module 2 – AWT – the Purchase Dr Darren Perrin

49. Process in Obtaining an AWT Define What Your Strategic Priorities Are Obtain Pre-Procurement Information Develop Procurement Strategy Develop Evaluation Criteria Develop Weightings Validate Weighting and Evaluation Criteria Commence Procurement Process

50. Defining Strategic purpose of AWT • Reduce the mass and volume of waste? • Produce an end product: • Quality Compost ? • Recyclables ? • High end value recyclables ? • Pre-treat the waste to produce a feedstock for another process? • RDF ? • SRF ? • Generate and export power or heat? • Electricity? • Heat / Steam ? • Biogas ? • Synagas ? • Stabilise the waste prior to disposal to landfill? • Maximise the life of landfill assets?