Agriculture Business Week

Imagine a pigpen that does not emit foul odor, and a household that enjoys free cooking gas and robust crops grown without chemical fertilizer. These are among the many benefits that Felimon “Boy” O Santander of Mandug, Davao City is enjoying nowadays, thanks to biogas technology that he has adopted.

Santander is one of the Magsasaka Siyentista, a part of the Farmer Scientist Bureau under the Techno Gabay Program which is one of the banner programs of the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development of the Department of Science and Technology.

In 1997, Santander, a Political Science graduate, has ventured into his own full-time hog project after being employed at the city government for 11 years. Today, he is concentrating in providing breeding services in his community and in neighboring towns and provinces. He maintains four boars that serve as a source of quality semen for use in artificial insemination services, and few heads for fattening. He is also into piglet and sow dispersal.

He recalled that one of the problems that he encountered was the foul smell coming from his pigpens since he and his family were residing in a subdivision with approximately 1,800 households.

Through constant research and self-training, Santander has perfected and was able to establish his own version of biogas digester in his backyard using the manure from his pigpen as the main input. It measures 6 cubic meters and now supplies the cooking gas requirement of 10 nearby households, including his own.

Santander said that foul odor was no longer a problem in the subdivision since his biogas digester was put up. “It eliminated the odor problem in our pigpens in no time,” he said.

Called modified biogas digester, Santander’s own design is made of concrete material. He said that it is made of three major parts: the inlet pipe, the digester or fermentation chamber, and the gasholder with hydraulic chamber.

His modified design is maintenance free because any non-biodegradable wastes that were accidentally mixed in the input materials are automatically rejected right at the inlet chamber. He assures that there is no danger of gas explosion as the digester is equipped with hydraulic chamber that regulates the pressure inside the gasholder. “Since it is enclosed, it cannot leak or affect the water table,” he added.

Biogas digester works by microbial conversion of organic matter under anaerobic (without oxygen) condition, which produces methane gas that can be used for cooking or even generate electricity when produced in huge volume.

“It is an environment-friendly technology because it minimizes, if not solve the effects of wastes disposed in the environment,” says Santander. Aside from hog manure, other suitable materials that can be efficiently utilized by the biogas digester are the manure from cattle, horse, goat, chicken, and human excreta; rice straw, corn stalk, wheat straw and other farm wastes; and any biodegradable materials.

The digester also produces sludge which can be discarded and used as organic fertilizer for crops. In fact, Santander applies the sludge on his crops to save on fertilizer costs. By the way, he also adopts integrated farming in his 1.5-hectare integrated farm near Panabo City in Davao del Norte where he grows mainly banana and raises few livestock the natural way.

Laboratory analysis of sludge matter shows that it contains 1.09% nitrogen, 10.13% phosphoric acid, 1.44% potassium, and 9.28% moisture content (oven dry).

For a typical household (4-5 members), he recommends a 2-cubic meter (m3) size digester which would require manure from 10 head of pig or not less than 20 head of chicken to sustain its operation. He said that the cost of establishment stands at P10,000 per cubic meter and the investment can be recovered in three years.

Santander’s success in biogas technology has encouraged other raisers in his area to put up their own digester with his assistance. He already assisted in the construction of more than 100 digesters ranging from 2 m3 to 50 m3 not only in Davao City but also in Davao del Sur, Compostela Valley, Davao del Norte, Bukidnon, Capiz, and in other parts of the country.

As a Magsasaka-Siyentista. Santander has been very active in the promotion of biogas technology by conducting technology clinics and fora through the help of Southern Mindanao Agriculture and Resources Research and Development Consortium. He also founded the Mandug People’s Cooperative with his neighbors who established their own pigpens and went into biogas technology as members.

Santander’s biogas technology. which was proven suitable both in the urban and rural areas, is being recommended for adoption by agriculture and, food sectors that are challenged on using alternative energy and renewable sources, and at the same time to save on production cost.