The device was developed during the 2001-2006 period by officials and researchers of the Department of Agriculture-Bureau of Soils and Water Management (DA-BSWM).
The BSWM team was composed of Director Rogelio N. Concepcion, Gina Nilo, Alan Anida, Carlos Serrano, Leonora de Leon, and Victorcito Babiera.
The innovative biogas generator was among the commerciable technologies presented at the 18th DA-Bureau of Agricultural Research National Research Symposium (NRS) conducted by BAR last Oct. 4-5 at its Research and Development Management Information Center (RDMIC) on Visayas Avenue in Diliman, Quezon City.
Conceived as an alternative source of fuel or energy for homes and farms in the countryside, Portagas uses biosolids and rice straw, in contrast to the existing fixed-structure generator, which primarily uses hog manure.
The concept was based from an earlier study on the use of digested rice straw as composed for soil fertility enhancement, wherein the by-products were methane gas (CH4), carbon dioxide (CO2), and hydrogen sulfide.
Results of the five-year BSWM study indicated that 100 kilograms of rice straw fed into the generator produced 25 cubic meters of biogas (63-64 percent CH4) equivalent to one cylinder liquefied petroleum gas (LPG) of 11 kg, which in turn is the approximate fuel requirement for 2-2.5 months of a typical Filipino family.
"Another interesting result," the BSWM research team said, "is that the nitrogen content of the compost that was produced increased from 0.6 percent in fresh rice straw to 1.5 percent, equivalent to two bags of organic fertilizer."
Another by-product is 750 liters of liquid fertilizer produced.
"Series of trials were made to improve the performance of the biogas generator and quality of the by-product," BSWM reported. – Rudy A. Fernandez