OMEGA-ALPHA RECYCLING SYSTEMS’ EFFORTS – DRACO I
I returned from my Peace Corps-Nepal adventure in late 1976 and began an intensive investigation of what I could find happening in the field of anaerobic digestion. This included extensive national and international correspondence, visits to active sites around the country, and study of the information gathered. Finally tiring of traveling to see what others were doing and telling folk what was being done and what could be done, I moved to central West Virginia in late 1978 with the idea of actually doing something. Some friends had moved there while I was in Nepal and were maintaining a goat-raising homestead at about the level I wished to apply the anaerobic digestion process.
In colder months, they cooked and heated with a wood stove and in warmer months they cooked outside to keep the house cooler. They had no electricity. They had a large organic garden onto which every spring they spread the year’s accumulation of bedding, urine and manure from the goat houses.
I had come to focus far more on the biological aspects of AD rather than the technological. I had also come to realize that small digesters could not be justified through gas production alone. Therefore, to be worth the effort of construction and operation, a digester had to be tightly integrated with other biological and technological systems surrounding it.
I had come across Vaclav Smil’s ~1976 article in, of all places, Bulletin of the Atomic Scientists, discussing biogas efforts in China with a drawing of one of the early fixed-cover designs. I was quite taken with having digestion and gas storage in one solid masonry tank . I felt that the temporary storage of digester supernatant above the gas-holding lid offered great potential for growth of water plants for animal feed and supplemental digester feed. I also saw the long digester wall as ideal for the back wall of a solar greenhouse.
So the idea was to build a system in which the greenhouse, digester and pond would interact symbiotically. The masonry digester was to be built into an east-west running hillside with a greenhouse on the south side. The digester would be operated in an “extended batch” mode. It would be loaded primarily in early spring with supplemental chicken residues and kitchen scraps added through fall. Some liquid fertilizer would be available throughout the growing season and the digester would be emptied in early winter. The common wall of the greenhouse and the digester offered much mutually beneficial heat transfer and storage. The tall thermosiphon (used gas equipment) drew hot air from the greenhouse through the base of the digester so as to passively gain more heat for the process. The pond on top seemed to offer possibilities for a wide range of production.
The system performed much as expected during the three years of operation before the owners moved – having sold the land to an uninterested out-of-state hunter. Gas production began within 1-2 weeks of loading and continued into early winter providing fuel for cooking and lighting. The liquid fertilizer produced excellent results and never burned any plants. Undigested solids were pitch-forked out by hand, spread on the garden, and planted in the next summer. Unfortunately, while the pond was seeded with water hyacinth, duckweeds, a water lily, and others plants, none of these were able to get established and the greatest growth was a thick blanket of algae – which was simply thrown into the digester for more gas.
I described and documented this effort at length for a 1983 alternative energy conference.
The following photos may give a better idea of what was attempted and done. All photos are from 1979-81. Next>