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Biogas Digestion by Michael Klima

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1 Biogas Digestion by Michael Klima


3 What is Biogas Digestion? Biogas Digestion is the process of taking biogas to produce electricity, heat, or hot water Biogas means a gas formed by carbon dioxide and methane from breakdown of organic materials such as manure.

4 What is a Digester? Digester is a vessel or container where the biogas process takes place. Bacteria breaks down manure or other waste products to create biogas. Products may be fed into the chamber such as manure or the container could be used to cover a place that is already giving off biogas such as a swamp or a landfill.

5 History of Biogas 1808 – Sir Humphrey Davy found that methane was present in the gases that is formed by the Anaerobic Digestion of manure 1884 – Louis Pasteur student, Ulysse Gayon, performed the anaerobic fermentation of manure and water at 35ºC and obtained 100 liters of Biogas per cubic meter of Manure. 1895 – Biogas is used to light up the streets in Exeter, England 1957 – A British Inventor, Bates, modifies his car to run on Biogas produced from pig manure. 2005 – The Biogas Support program in Nepal wins the Ashden Reward for installing over 150,000 Biogas Plants in rural areas. And a Biogas powered train starts it's service in Sweden

6 Reasons of Interest in Biogas Anaerobic Digester systems Improved Technology in systems has led to reliability Good way to manage manure given the odor and environmental concerns associated with manure Government has subsidized programs for systems Potential to sell credits to utilities and utilities continue interest in green energy

7 Biogas Process

8 Design of a Digester

9 How Digester Works Temperature must be kept between 65 degrees and 150 degrees 4 Types of bacteria breakdown the waste – Hydrolytic breaks organic material to simple sugar and amino acids – Fermentative then converts to organic acids – Acidogenic convert to carbon dioxide, acetate, and hydrogen – Methanogenic produces biogas

10 Combined Heat and Power Also known as cogeneration Using the heated water for other purposes such as heating buildings or creating additional energy


12 Sources of Biogas Wetlands Sewage Sludge Landfills Plant Material Animal Waste


14 Number of United States Operating Anaerobic Digesters by Technology

15 Complete Mix Digester – Are larger vessels that can either be above or below ground. They are used for larger amounts of manure Plug Flow Digester- Is used for ruminant animal manure and requires little maintenance. Better for smaller operations

16 fixed film digester – “a tank designed as part of a manure management system to handle manure up to 3 percent solids. The digester is temperature controlled and a media is placed inside the digester. This design allows the microbial populations to attach to the media and grow as a biofilm (fixed film), thus preventing the microbes from being removed with the effluent”

17 temperature-phased anaerobic digester (TPAD) – “two tanks designed as part of a manure management system. The digesters are heated, the first digester in the thermophilic temperature range and the second digester in the mesophilic temperature range. This will maximize biological activity for the destruction of volatile solids, methane production and odor reduction.”

18 covered lagoon digester – “an anaerobic lagoon is commonly used when manure has less than 2 percent solids. Decomposition of the manure occurs, methane is produced and effluent odor is reduced. The lagoon is covered with a gas-tight cover to capture the biogas.”

19 A landfill gas-to-energy – “consists of a series of wells drilled into the landfill. A piping system connects the wells and collects the gas. Dryers remove moisture from the gas, and filters remove impurities. The gas typically fuels an engine-generator set or gas turbine to produce electricity. The gas also can fuel a boiler to produce heat or steam. Further gas cleanup improves biogas to pipeline quality, the equivalent of natural gas. Reforming the gas to hydrogen would make possible the production of electricity using fuel cell technology.”

20 US Government Involvement

21 Regulations On March 20, 2009 revised the new source performance standards to limit when owners/operators of stationary combustion turbines using biogas had to install emission controls and/or pretreatment systems to remove sulfur compounds Biogas is recognized as an advanced biofuel under 42 U.S.C.A. § 7545

22 Financial Incentives Since 2003 USDA has awarded 37 million to anaerobic digestion systems

23 EPA AGSTAR Study of Two farms ParameterWith anaerobic digestion OdorSubstantial reduction Greenhouse gas emissionsMethane—substantial reduction (3.03 tons per cow-yr on a carbon dioxide equivalent basis) Nitrous oxide—No evidence of emissions with or without anaerobic digestion Ammonia emissionsNo significant reduction Potential water quality impactsOxygen demand—substantial reduction (8.4 lb per cow-day) Pathogens—substantial reduction (Fecal coliforms: ~99.9%) (M. avium paratuberculosis: ~99%) Nutrient enrichment—no reduction Economic impact Significant increase in net farm income ($82 per cow-yr)

24 Benefits and Concerns

25 Benefits of Biogas Digester Systems Odor Reduction by using raw manure If Ammonia, a by-product of process, is captured can be used to help plant growth by injecting it into the ground Reduction of Electricity for Farms Carbon Dioxide generated from biogas digester systems creates less greenhouse gas then methane gas used in initial process

26 Biogas Digester System Concerns Releases Nitrogen and ammonia into the atmosphere both of which hazardous Can release Hydrogen Sulfide a very toxic gas Methane released can create explosive atmosphere Should raw materials get into water supply can contaminate the water Transportation is of a concern because methane is explosive although new technology may allow it to be stored in powder form

27 Current U.S. Examples Central Vermont of 158,000 customers 4,000 have agreed to pay a small premium to use biogas energy Panda Ethanol Plant in Texas Columbia Boulevard Wastewater Treatment Plant in Portland, Oregon produces 1.5 million kilowatts of energy per year

28 Other Countries use of Biogas Nepal Africa Ecuador Sweden

29 Nepal Since 2003 Nepal has built 94,425 small biogas plants for individual use One plant costs approximately $593 USD (2009 estimate) Nepal has subsidized half the cost for farmers willing to build these biogas plants Nepal has targeted farmers with at least one cattle and owns a small piece of land

30 Benefits from Nepal's Prospective Saves from deforestation because main source of Nepal’s farmers power is wood burning Has created 13,000 jobs since 2003 for those who build these small plants Reduces air pollution because biogas burns cleaner then wood Improves women and girls lives because the plants reduce overall work by about 3 hours then collecting and cooking with fire wood leaving more time for education

31 Africa Biogas distributors cost about $50 per family Currently Nigeria is working on a biogas project that will provide gas to 5,400 people and cost $300k

32 Ecuador Biogas Sewage Project A large education complex called Santa Maria del Fiat did not have proper sewage system and would simply dump waste in open spaces. This contaminated underground water sources and created sever odors The project built a biogas digester that processed both human and animal waste

33 Ecuador Biogas Sewage Project Continued The school also built a water reclamation system During school year the 500 students waste is used to produce over 40% of the school’s gas electricity. Power is also produced in the summer from local farmer’s animal and vegetable waste The school sells the fertilizer by product and uses the fertilizer in the schools own orchid

34 Sweden Biogas Train Train runs on entrails of slaughtered cows Costs 20% more to run on methane then diesel right now Sweden is 10 times ahead of its European counter parts for binding goals the European Commission as setup for use of bio-products by the end of the year 2010 Sweden also has 65 fleet of biogas buses

35 Conclusions Biomass counts for only 4% of United States yearly energy use Biogas works best on small scale operations Has technology improves we will be able to use methane gas more efficiently Good way to put human and animal waste to good use

36 Notes-Citations Slide 3- Slide 4- Slide 5- Slide 6- Slide 7- /biogas%20principle.html Slide 8- Slide 9- Slide 10- Slide 11- Slide 12- Various sources see Slide 13-No need for citation

37 Notes-Citations Continued Slide 14- Slide 15- Slide 16- Slide 17- Slide 18- Slide 19 - Landfill_Gas Slide 20- No Citation needed Slide-21- SO2 EMISSION LIMIT FOR UNITS BURNING BIOGAS ADDED TO NSPS FOR STATIONARY COMBUSTION TURBINES (19 NO. 4 Air Pollution Consultant 2.13) Slide 22- Slide 23-

38 Notes-Citations Continued Slide 24-No citation needed Slide 25- Slide 26- Slide 27- 24farmers.html Slide 28-No need for a citation Slide 29- Slide 30- Slide 31 – Borders and Environment by Andrew P. Morriss and E. Roger Meiners 39 Envtl. L. 141) Slide 32- Slide 33- Slide 34- Slide 35- k.cfm

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