Advance Biofuels Leadership Conference, April 19-21, 2011 at the Capital Hilton, Washington, DC.

High Concentration Anaerobic Bioreactor 

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High Concentration Anaerobic Bioreactor

1. Overview of waste to energy technology application

2. Technical Basis description for the proposed approach

3. Process Requirements for Waste to Energy Technology Application

4. Feedstock for the reactor

5. Green Considerations

6. Full-Scale Implementation Approach

7. Financial Evaluation

High Water Content Organic Wastes

HCAB

Cheap / Sustainable Power

Marketable By-Product (compost)

Unique Niche:• An alternative, independent,

secure and sustainable power source.

• No Drying of Wastes• Dramatic reduction in solid

waste disposal & wastewater treatment costs.

Overview of Waste to Energy Technology Application

Overview - High Concentration Anaerobic Bioreactor Process

Technical Basis - High Concentration Anaerobic Bioreactor

Anaerobic Digestion

• Anaerobic digestion is one of the oldest forms of biological wastewater treatment.1

• The first of anaerobic digestion can be traced back to the 1850s. 1

• First U.S. application of anaerobic digestion occurred in Baltimore in 1911. 1

• The Process of Anaerobic Digestion was extensively studied from 1920 to 1935, during that time major improvements were made regarding tank design, temperature control , and appurtenant equipment. 1

• Essentially the same biological process occurs today; i.e. No specialized bacteria are need to implement the technology. 1

• While great progress has been made in the process, the same basic principles are still followed today1

Waste to Energy Technology Application

High Concentration Anaerobic Bioreactor

High Solids Anaerobic Digestion (HSAD)

• National Renewable Energy Laboratory (NREL) pioneered a thermophilic HSAD to convert biomass feed stocks into biogas in the mid-1990’s. Their work:

– Demonstrated the viability of digestion of soluble and insoluble COD from waste streams with a total solids content of up to 60 percent: however

– Ran into trouble realizing the potential of high solids digestion as their solids mixing design is torque limited (only able to run their reactors at 15% solids)

• European work on anaerobic systems for use in digestion of municipal solid waste (MSW) include four designs that have been demonstrated to effectively mix waste streams containing more than 25% solids (dry digestion)

• Four European companies include: Kompogas, Linde, Valogra, Dranco6

• These processes can be differentiated from the ARCADIS process based on material flow, mixing method, hydraulic residence time, and reactor size6 European small reactor sizes exist due to limitations in design related to mixing.

Technical Basis for Waste to Energy Technology Application

High Concentration Anaerobic Bioreactor

• The HCAB process is a unique combination of existing technologies. The main advancement is the proprietary engineering breakthrough using unique mixing and large reactor volumes, thus allowing the reactor to be operated at very high solids concentrations.

– HCAB can process 5-10 times the amount of waste of a standard anaerobic reactor (Wet Digestion)

– HCAB can produce 5-10 times the amount of methane of a standard anaerobic reactor

– The technology can be scaled beyond small reactors (100 ft. diameter), resulting in cost advantages

• The process uses naturally occurring, anaerobic bacteria - the same bacteria found in landfills, wastewater digesters ,etc., meaning no specialized bacteria needs to be developed.

• The equipment design is based on standard motor, gear drives, etc., already used by major equipment manufacturers. There is no need for the purchase of specialized spare parts.

Technical Basis for Waste to Energy Technology Application

Process Requirements - High Concentration Anaerobic Bioreactor

Bioreactor Plant Requirements

• Power: Three phase electrical power will be required to operate the reactors

– This cost (which is factored into our O&M costs) is estimated at $200,000 / year per reactor. It could be offset by the power generated by the unit.

• Water requirements: Fresh water supply is minimal and not an essential component of the process

• Waste disposal requirements: ~ 25,000 – 50,000 gallons per day of wastewater high BOD wastewater that will require pretreatment prior to discharge or direct discharge to a POTW

• Space requirement: Approximately 4 acres of land will be needed to support full-scale plant operations including storage/processing of “feed” material

• Housing / structural requirements: A building for the control system, scrubber, and solids handling system will be required (estimated to be 16,000 to 20,000 square feet)

• Access: Road access to install and operate the Plant is needed – probably want separate entry from main base for waste delivery

Waste to Energy Technology Application

High Concentration Anaerobic Bioreactor

• Personnel requirements– Wastewater treatment training and licenses will cover O&M personnel needs

– One senior operator and 3 assistant operators are required

– Personal protection equipment: Level D protection

• Climate restrictions– None

• Useful Byproducts– Methane (power)

– Compost

Process Requirements for Waste to Energy Technology Application

Feedstock Considerations - High Concentration Anaerobic Bioreactor

• Of the 254 Millions tons of municipal solid waste generated each year, food waste accounted for over 31 million tons and yard waste another 32 million tons.2

• Multiple states across the country manage recycling and compost programs for food waste and/or yard waste (green waste).

– BioCycle's 2007 nationwide survey identified 42 communities and/or counties with source separated residential organics collection programs in the U.S. This is an increase of 12 from BioCycle's 2006 data (reported in the January 2007 issue). There are 17 programs in California, 1 in Michigan, 7 in Minnesota and 17 in Washington State (all in King County). 3

– California initiated Strategic Initiative 6 in 2007

• Calls for the amount of organics in municipal waste to be reduced by 50% by 2020 4

• Hillsborough County Florida Process 170,000 tons of yard waste annually at composting facilities5

– Yard and/or food waste programs and the infrastructure to collect these waste streams exist in many states including California, Washington, Arizona, Virginia, Florida, Minnesota, Ohio, Pennsylvania, Maryland, and North Carolina.

Waste to Energy Technology Application

Green Considerations - High Concentration Anaerobic Bioreactor

Air pollutants: No air pollutants are released from the process. The gas generated is captured and put to beneficial use.

Water Pollutants: No water is require for this process. In fact, a small amount of water is produced. This water can be directly used for irrigation. The water may require a small amount of treatment if directly discharged.

Hazardous Waste: No hazardous wastes are produced in connection with this process.

Energy Requirements: The small amount of energy required by the bioreactor and pumps represents about 10% of the energy produced from the same reactor.

Landfilling: The material fed to the bioreactors is waste. Any material brought to the reactor will avoid landfill applications and associated costs.

Compost: The reactor produces a highly beneficial compost that can be applied directly to land. This material has been shown to have financial value.

Full Scale Implementation - High Concentration Anaerobic Bioreactor

• Bioreactor system components / size

─ 6-ft diameter vessel with an approximate 4-ft water depth

─ Operating volume of approximately 850 gallons (114 ft3). The head space volume in the tank will be approximately 300 gallons (40 ft3).

Pilot Plant Testing

Financial Evaluation

Assumptions• 1 – 100 ft HCAB with Sulfur Treatment – 200 tons/day throughput

• Plant has a better than 95% operating Concentration (350 days of operation per year)

• Tipping fees of $32.50/ton are received for receipt of feedstock material (landfill avoidance)7. Tippage weight is 73,000 tons/year.

• Saleable compost will be generated from the process for $8/cubic yard, compost generation is 26,000 cubic yards/year.

• Gas generation will be 313,000 mmBtu/year.

• Capital cost of $6.0M

• Yearly O&M costs are $2.0M

High Concentration Anaerobic Bioreactor

Agricultural Crop

Biogas

Food Waste & Misc. Cellulosic Waste

Materials

Ag or Food Waste

High Conc. Anaerobic Bioreactor

(HCAB)

Compost

Compost Processing

Water Reuse

Nutrient / pH Adjustment

Compost

Biogas Conditioning – Sulfur Removal

Conditioned Biogas

Biogas Boiler

Cogeneration Turbine Generator

Electricity

Recycle

Hopper / Grinder

Waste to Energy Technology Application – Flow Diagram

To Natural Gas Pipeline

Steam To

Process Application

• Biogas Production and Direct Use

– $7.53/ MMBTU (without other income)

– $0.61/ MMBTU in operating profit (including income from tippage and compost)

– This compares to the current Henry Hub Spot Price for natural gas of $4.20 (February 25, 2009), and a three year weekly average of $7.52

• Electricity Production

– $0.13/KWhr (Without other income)

– $ 0.006/KWhr ( including income from tippage, compost and national and local incentives)

– This compares to a National Average for Residential power of $0.1091 kw-hr (in 2008) (source:http://www.neo.ne.gov/statshtml/115.htm and http://www.pacificpower.net/Article/Article45955.html)

• Natural Gas Quality Production

– $10.17/MMBTU (Without other income)

– $2.03/MMBTU (With income)

– This compares to the current Henry Hub Spot Price for natural gas of $4.20 (February 25, 2009), and a three year weekly average of $7.52

Financial Evaluation - High Concentration Anaerobic Bioreactor

References

1 Wastewater Engineering Treatment, Disposal, and Reuse, Metcalf and Eddy, Third Edition

2 United States Environmental Protection Agency, Office of Solid Waste, EPA530-R-08-010, Municipal Waste in the United States, 2007 Facts and Figures

3 Source Separated Residential Composting in the U.S., Biocycle, December 2007, vol 48, No.12, p27

4 http://www.ciwmb.ca.gov/BoardInfo/StrategicPlan/5 Growing Like a Weed, WasteAge, May 1, 20056 Anaerobic Digestion and Feasibility Study for the Bluestem Solid Waste Agency

and the Iowa Department of Natural Resources, R.W. Beck, June 20047 The State of Garbage in America, Biocycle, December 2008, vol 49, No 12.

Imagine the result