Elsewhere in Asia: World Digesters
ANAEROBIC DIGESTION SYSTEMS ELSEWHERE IN ASIA AND LESS-OVERDEVELOPED AREAS
CAPTION: Bovine (cow, water buffalo, etc.) manure fuel cakes drying on convenient walls. (1975) As with coal briquets in China, adequately and sustainably substituted for
With China and India leading the way, since the early 1980s there has been much effort devoted toward popularization of smaller-scale AD possibilities throughout Asia and in most other less overdeveloped areas. In India, both the fertilizer and gas values were a co-focus from the beginning. The primary Indian design was a floating drum cover on top of a well filled with digesting materials. (“Gobar” is the term for bovine manure and the digesters are known as Gobar Gas Plants.)
During the late 70s through 90s, there was considerable interest in the solid masonry digesters along the Chinese design. Many Chinese researchers, technicians and masons provided assistance throughout the region and, through UNEP, as far afield as South America. There is now a massive amount of information on many of these efforts to be found on the web.
The majority of earlier efforts were focused on digester design, construction and operation. There was however also recognition of some of the possibilities for highly integrated and productive systems which included digesters. In China, India, Brazil, , and many other countries, such systems have been envisioned and manifested in varying degrees. (See OARS’ Systems.)
One development I found especially interesting was the “red mud” digesters in Taiwan in the late 1970s. Red mud is a toxic waste produced during the bauxite mining and purification process. There are lakes of this hard-to-dry ooze found in these mining areas. It was found that, once this material was dried, it could be added to plastic mixtures with the resulting sheets being resistant to the ultraviolet in sunlight for more than 10 years.
I offer the following images of early biogas activity in less overdeveloped regions.