1 / 15

Anaerobic Co-digestion of Biomass for Methane Production : Recent Research Achievements

Anaerobic Co-digestion of Biomass for Methane Production : Recent Research Achievements . Wei Wu CE 521 . Introduction . Anaerobic Digestion . Anaerobic digestion (AD) Organic Matter + H 2 O + Bacteria CH 4 + CO 2 + NH 3 + H 2 S Traditionally

torin
Télécharger la présentation

Anaerobic Co-digestion of Biomass for Methane Production : Recent Research Achievements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Anaerobic Co-digestion of Biomass for Methane Production : Recent Research Achievements Wei Wu CE 521

  2. Introduction

  3. Anaerobic Digestion • Anaerobic digestion (AD) Organic Matter + H2O + Bacteria CH4 + CO2 + NH3 + H2S • Traditionally • Single substrate and single purpose • Manure was digested to produce energy • Sewage sludge should be stabilized • Industrial waste water should be pre-treated • Recently • Co-digestion of two or more substrate and multi-purpose

  4. Co-digestion • Co-digestion • Two or more substrates • Major amount of a main basic substrates (e.g. manure or sewage sludge) + Minor amount of a singe, or a variety of additional substrates • Multi-purpose process serving at the same time • Waste upgrading • Energy production • Improvement of fertilizer quality

  5. Co-digestion—Cont. • Factors impact the production of biogas • The type of waste being digested • Its concentration • Its temperature • The presence of toxic materials • The pH and alkalinity • The hydraulic retention time • The solids retention time • The ration of food to microorganism • The rate of digester loading • The rate at which toxic end products of digestion are removed

  6. Improve the C/N ratio, buffering capacity and more biodegradable substrate Benefits of Co-digestion • Improved nutrient balance and digestion performance • A nutrient ratio of TOC:N:P = 300:5:1 to achieve optimal digestion performance Manure Low C/N ratio– high ammonia High alkalinity Rich in macro/micro nutrient Crop or Crop residues High C/N ratio– high carbon content Low alkalinity Lack of macro/micro nutrient

  7. Benefits of Co-digestion • Effective utilization of digester volumes • Help to utilize the availability of free capacities • Co- digestion of energy crops and manure resulted in the doubling of the plant capacity from 500 kW to 1000 kW retaining the digester volume (Lindorfer et al., 2007) • The wide distribution of sewage treatment plants minimizes transportation costs • Equalization of particulate, floating, settling, acidifying etc. wastes, through dilution by manure

  8. Types of digester Mesophilic AD Approximately 30-35° C Retention time of 15 – 30 d Continuously stirred tank reactors (CSTRS) under mesophilic conditions Co-digestion • Thermophilic AD • Exceed 55 ° C • Retention time of 12-14 d

  9. Co-digestion • Source of organic waste streams can be co-digested with manure • Food Industry • Waste from potato, sugar beet, meat, and dairy processing • Grain Industry • Damaged grain • Paper Industry • Newspaper and recycled paper • Domestic Wastes • Livestock Wastes • Crop Residues • Corn stover and switchgrass

  10. Increased by 65 % Cow manure alone Cow manure alone Cow manure alone Manure + 30% sugar beet tops Manure + 30% grass Manure + 30% oat straw Increased by 58 % Increased by 16 % Case 1 Lehtomaki et al., 2007

  11. Case 2 • Whey co-digestion with diluted poultry manure • For an hydraulic retention time of 18 days at 35 ° C and organic loading rate of 4.9 g COD/L • Biogas production increased by 40% Gelegenis et al., 2007

  12. Case 3 • Co-digestion of solid slaughter house waste, fruit-vegetable wastes, and manure • Possibility to treat combined waste of • Manure (cattle and swine) • Solid slaughterhouse wastes (rumen, paunch content, and blood from cattle and swine) • Fruit-vegetable wastes Alvarez et al., 2007

  13. Drawbacks of Co-digestion • Increased digester effluent chemical oxygen demand (COD) • Additional pretreatment requirements • Increased mixing requirements • Wastewater treatment requirements • High utilization degree required

  14. Conclusion • Co-digestion offers several possible ecological, technological, and economical advantages • There is very limited research, specifically in the U.S., that characterizes the digestibility of a number of the waste streams • The potential economic impact of fully utilizing alternative waste streams with AD of manure seems to be great, but economic analysis must be done to quantify this information

More Related