June 2005 update. Professor George Chan (on left with Patricio Guerrero Ortiz, a local engineer assisting us) returned to New Mexico to establish a small biodigester system in the greenhouse of the Danny Sam family. The biodigester from the SCZ Picuris Pueblo 2002 test set up was used. Four large troughs were connected at successively lower levels so that gravity would move the liquid in them.
Equal parts of water and animal manure will be added to the biodigester. Anaerobic bacteria take about one month to break down the wastes into a pathogen-free slurry. This liquid flows out of the biodigester through a pipe connected to the first sedimentation trough where baffles allow the sludge to settle out and be removed. The remaining liquid flows to the second trough where finer sludge settles out and is removed. Again the remaining liquid flows to the third trough which is for oxidation and from there to a second oxidation trough. The final liquid can be used as fertilizer for crops within the greenhouse
Biogas is also produced in the biodigester as a result of the bacterial break down of the wastes. It will be captured and stored in an empty propane tank. There are many uses for biogas e.g. providing light, heat, sterilization of sludge prior to mushroom growing, or for cooking in the home.
Sludge from the sedimentation troughs can be used to grow mushrooms or in vermiculture to grow earthworms as food for chickens or other fowl.
In a larger biogas system, using ponds instead of troughs, edible algae can be harvested from the oxidation ponds for high protein food or to feed ruminants, another type of algae can produce biodiesel fuel.
Liquid nutrients in these oxidation ponds will feed phytoplankton and fish can thrive on them. Fecal matter from the fish will make the water useful for fertilizer and crop irrigation. When all these benefits are taken together, they make a positive picture of what was a disposal problem.
Professor Chan (at left in photo on the right with Gunter Pauli) moved on to Colorado where he was present for the graduation of the 3rd module of the 4th ZERI Certification Training. (See Education web page) He also presented a workshop where he established a biodigester system for the La Boca farm/ranch.
In 2002 SCZ was working with several organizations: the Border Environmental Cooperation Commission, poor communities along the US/Mexico border, pueblos (notably Picuris), and dairy farmers in southern New Mexico, on a human/animal wastewater treatment system. This system converts wastewater into "nutrients" for agriculture and fish farming activities as well as creating biogas for energy.
At present we are waiting for the USDA to determine that this system will address Picuris Pueblo's sanitation needs. This would be the first system of its kind in the United States and could become a model for low-cost sanitation treatment systems with value-added economic benefits.
For more information on Integrated Waste Management and Farming System go to the following links.
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