Method and apparatus for hydrogen production from organic wastes and manure
A method for hydrogen production from biodegradable feedstocks in which a feedstock having at least one biodegradable solid is introduced into a first stage anaerobic bioreactor operating at thermophilic conditions to form a liquid effluent which includes fatty acids. The liquid effluent is transferred through a plurality of hollow semipermeable fibers disposed in a second stage anaerobic bioreactor having a light transmitting wall, which hollow semipermeable fibers have an outer surface coated with a biofilm of photosynthetic bacteria, which photosynthetic bacteria, using the nutrients in the hollow fibers and the incoming light, generates hydrogen.
1. A method for hydrogen production from biodegradable feedstocks comprising the steps of:
introducing a feedstock comprising at least one biodegradable solid into a first stage anaerobic bioreactor operating at thermophilic conditions, forming a liquid effluent;
transferring said liquid effluent through a plurality of hollow semipermeable fibers disposed in a second stage anaerobic bioreactor having a light transmitting wall through which light is transmitted, said hollow semipermeable fibers having an outer surface coated with a biofilm comprising photosynthetic bacteria, forming hydrogen gas; and
exhausting said hydrogen gas from said second stage anaerobic bioreactor.
2. A method in accordance with claim 1 , wherein said first stage anaerobic bioreactor is operated with substantially zero-headspace.
3. A method in accordance with claim 1 , wherein said first stage anaerobic bioreactor is operated at a temperature in a range of about 45° C. to about 65° C.
4. A method in accordance with claim 1 , wherein said liquid effluent comprises at least one fatty acid.
5. A method in accordance with claim 1 , wherein at least a portion of said liquid effluent in said hollow semipermeable fibers is recycled to said first stage anaerobic bioreactor.
6. A method in accordance with claim 1 , wherein said first stage anaerobic bioreactor and said second stage anaerobic bioreactor are constantly stirred tank reactors.
7. A method in accordance with claim 1 , wherein said biodegradable solids comprise a material selected from the group consisting of manure, food processing wastes, energy crops and mixtures thereof.
8. A method in accordance with claim 1 , wherein said photosynthetic bacteria comprise at least one of an axenic culture and a mixed culture.
9. A method in accordance with claim 1 , wherein said first stage anaerobic bioreactor is an acidogenic bioreactor.
10. A method in accordance with claim 1 , wherein a portion of said liquid effluent in said hollow semipermeable fibers is dewatered, resulting in formation of biosolids.
11. A method in accordance with claim 1 , wherein said first stage anaerobic bioreactor generates biosolids.
12. A system for producing hydrogen comprising:
a first stage anaerobic bioreactor vessel having a feedstock inlet and a liquid effluent outlet;
a second stage anaerobic bioreactor vessel having a light transmitting outer wall, a liquid effluent inlet in fluid communication with said liquid effluent outlet and a hydrogen gas outlet;
a plurality of hollow semipermeable fibers disposed in said second stage bioreactor vessel adapted to receive liquid effluent from said liquid effluent inlet; and
at least one photosynthetic bacteria disposed in said second stage anaerobic bioreactor and external to said plurality of hollow semipermeable fibers.
13. A system in accordance with claim 12 , wherein said first stage anaerobic bioreactor is operable at substantially zero-headspace.
14. A system in accordance with claim 12 further comprising recycle means for recycling a portion of liquid effluent disposed in said second stage anaerobic bioreactor into said first stage anaerobic bioreactor.
15. A system in accordance with claim 12 , wherein said at least one photosynthetic bacteria is an axenic culture.
16. A system in accordance with claim 12 , wherein said at least one photosynthetic bacteria is a mixed culture.
17. A system in accordance with claim 12 , wherein said first stage anaerobic bioreactor and said second stage anaerobic bioreactor are constantly stirred tank reactors.