This document discusses high solids anaerobic digestion as a solution for processing high solids content organic waste. It notes that many organic waste streams naturally occur at 30% solids or higher, but conventional digestion requires dilution. High solids digestion offers benefits like minimized dilution, smaller footprint, and increased feedstock flexibility. The document provides an overview of high solids digestion systems and components, and highlights several reference plants using the technology to process municipal solid waste and agricultural waste.

1. Anaerobic Digestion for High Solids Content
2013 International Biomass Conference & Expo -
The Dilution Solution: Using High Solids Anaerobic Digestion to Diversify Feedstock Options
John McDowell, Sales Engineer
www.eisenmann.com
www.eisenmann.us.com
© Eisenmann AG 2013
© Eisenmann 2013

2. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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3. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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4. Anaerobic Digestion Process
…the degradation and stabilization of organic
material generating a mixture of methane and
carbon dioxide (called Biogas) by bacteria in
an oxygen free environment.
Biogas
For electricity, heat,
vehicles, pipeline
Organic Digestion System Co-Products
Material
Soil amendments,
Food and yard waste,
nutrients, compost,
agriculture waste
livestock bedding
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5. Biogas Production
Hydrolysis Acidogenesis Acetogenesis Methanogenesis
Acidification phase Acetic acid formation Methane formation
Pre-treatment Anaerobic fermentation Output Digested
(in 4 phases) substrate
Substrate input to
anaerobic
fermentation
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6. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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7. Input Materials
Organic input substrates supplied from:
 Agriculture
 Food processing facilities
 Restaurant waste
 Yard waste and grass clippings
 Waste management facilities
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8. Municipal Solid Waste
Total MSW Generation (by Material)
250 Million Tons (Before Recycling)
 34 Million Tons of Foodwaste
 33 Million Tons of Yard Trimmings
Source: US EPA, 2010
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9. Municipal Solid Waste Recovery
Total MSW Generation (by Material)
Generated and Recovered
 Foodwaste
• 34.76 million tons generated
• 0.97 recovered
• 2.8% recovery rate
 Yard Trimmings
• 33.40 million tons generated
• 19.20 recovered
• 57.5% recovery rate
Source: US EPA, 2010
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10. Problem
Issues
 Vast number of organic substrates naturally occur around a level of 30% solids and higher
 Dilution is not desired as it increases the amount of effluent
• Recirculating effluent can concentrate inhibitors
Low Solids Digestion Technology
 Requires low solids feedstock – up to 15% total solids
 Requires dilution of feedstock to allow mixing and avoid sedimentation in large vessels
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11. Biogas Yield
Biogas Yield Varies by Feedstock
 Higher solid based feedstocks
tend to yield a higher gas rate
 Feedstock age also impacts
Biogas Yield
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12. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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13. Benefits of High Solids Digestion
 Minimized feedstock dilution and recirculation rates
 Feedstock flexibility
 Allows for smaller footprint
 Maximum gas yield
 System stability
 Seamless system integration
 Increasing close-loop systems
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14. Process Overview
High Solids Contaminate Walking Floor
Receiving Hall
Wastes Removal Container
Biogas Main Digester
Substrate Receiving
Substrate Preparation
Storage Liquid Effluent
Substrate Dosing Separator
Biogas
Composting Press Cake
Digestate
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15. High Solids Flow Schematic
Post Digester
Solids Separation
Biogas
Substrate Feed
Consumer
Substrate
Conditioning Pump Room
Main Digester
Biowaste AD System 3D-Model
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16. Substrate Conditioning - Grinding
Quick grinding of larger size, inhomogeneous substrates
 Suited for yard and landscape waste
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17. Substrate Conditioning - Screening
Loosening, sieving, transport, removal of oversize contaminants
 Suited for green bin, yard, and landscape waste
Star screen
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18. Substrate Conditioning - Chainmill
Rotating chain links depackage and macerate substrate
Avoids overshredding of packaging material for easier removal
 Suited for green bin waste streams
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19. Substrate Conditioning - Hammermill
Substrate is macerated and homogenized with hammermill
Organic material is macerated; packaging and contaminants are separated
 Suited for packaged pre- and post-consumer food waste and slaughterhouse waste
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20. Substrate Feed System - Solids
Provides buffer storage of conditioned, high solids organic waste
 Suited for stackable and bulk materials
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21. Substrate Feed System - Liquid
Receiving pit and/or tanks for liquid organic materials
Receives and provides buffer storage
 Suited for all pumpable organic material
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22. Main Digester - Steel
Continuously mixed horizontal plug-flow digester for high solids organic waste
Modular design
Insulated with an internal heating system
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23. Main Digester - Concrete
Continuously mixed horizontal plug-flow digester for high solids organic waste
Modular design
Precast or cast in place construction
Insulated with an internal heating system
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24. Horizontal agitator
Continuously mixes and homogenize substrate
Designed to continuously mix substrates with high total solids content
Optimizes proper gas release
External bearings, low RPM
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25. Digestate Handling
Hose pumps and heavy duty piston pumps used to remove and convey digestate from
main digester vessel
Suction pumps with less wear parts and easy maintenance
 Suited for digestate with lumpiness and high viscosity
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26. Solids Separation
Screw press separators remove non-digestible solids
 Press cake – 30-35% total solids
 Press water – 8-20% total solids
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27. Post digester
Covered vessel for residual gas production
Provides liquid effluent storage and biogas storage
Size varies depending on storage requirements
Submersible mixers
Double membrane gas storage
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28. Biogas Consumer - Combined Heat & Power (CHP)
Specially designed internal combustion engine powers generator for electricity production
Electricity can be used on-site or fed into utility or micro grid
Thermal energy used to heat digestion process, industrial processes or district heating
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29. Biogas Consumer - Upgrading
Upgrading can be achieved through highly selective membrane technology
Removal of Carbon Dioxide to produce concentrated methane gas
Fed into utility pipeline system (RNG)
Utilization as vehicle fuel (CNG)
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30. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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31. Municipal Biogas Plant
Built: Capacity: 12,000 t/yr
Digester size: 212,000 gallons
2010
Location: Biogas flow: 88 CFM
Installed electrical capacity: 330 kW
Switzerland
Substrate:
manure, post consumer foodwaste
from green bin collection, yard waste,
food manufacturing residue
Main and post digester Biogas piping
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32. Biogas Plant with Pushfloor Delivery
Built: Capacity: 20,000 t/yr
2012 Digester size: 2 x 212,000 gallons
Location: Biogas flow: 153 CFM
Sweden Biogas upgraded to CNG, used to fuel public
Substrate: transportation vehicles
post consumer foodwaste from
green bin collection, yardwaste
3D Rendering Double concrete main digester with pushfloor substrate delivery system
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33. Steel Biogas Plant
Built: Capacity: 12,000 tons/year
Digester size: 2 x 86,000 gallons
2010 Biogas flow: approx. 165-176 CFM
Location: Installed electrical capacity: 620 kW
Italy
Substrate:
slurry, chicken manure,
diverse types of silage,
olive press cake, waste animal feed
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34. Urban Biogas Plant
Built: 2013 – under construction
Location: USA - Chicago Capacity: 5,000 tons/year (phase 1)
Substrate: spent brewers grain,
food waste Digester size: 86,000 gallons
Biogas flow: approx. 42 CFM
Installed electrical capacity: 105 kW at 30%
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35. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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36. Leading International Supplier
 Environmental technology
 General finishing
 Material handling & conveyor systems
 Process and high-temperature technology
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37. Offerings
 Green, sustainable engineering
 Top quality and reliability
 Modular and custom solutions
 Detailed system and process solutions
 Dedicated industrial service team
 Worldwide reference installations
 Global services
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38. Facts and Figures
 Established 1951; Stuttgart, Germany
 12 locations worldwide
 US location since late 70‘s; Crystal Lake, IL
 3,600 employees
 More than 90 Biogas facilities
Founding
Member
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39. Eisenmann Biogas
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40. Agenda
1 Anaerobic Digestion
2 High Solids Feedstock
3 High Solids Digestion
4 Reference Plants
5 About Eisenmann
6 Conclusions and Questions
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41. Conclusions
 Organic waste makes up more than 27% of all municipal solid waste generated
 Organic waste is supplied from various sources
 Most organic substrates naturally occur around 30% total solids
 High solids digestion offers many advantages including minimum dilution, smaller
footprint, and feedstock flexibility
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42. Questions
Green Engineering
Sustainability is in Our System
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43. New Website
Introducing Eisenmann’s New Website
www.eisenmann.us.com/biomass13
Available for download:
 Today’s presentation
 CNG to Fuel your Fleet
(white paper)
 Sustainability in an Urban Environment
(white paper)
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44. Contact
John McDowell
Sales Engineer
Phone: (815) 477-5335
E-Mail: john.mcdowell@eisenmann.com
150 East Dartmoor Dr. Crystal Lake, IL 60014
www.eisenmann.us.com
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Eisenmann Corporation Eisenmann Corporation @EISENMANNUSA
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