A PROJECT to utilize waste from rice farms as biofuel has taken off the ground through a collaboration involving the Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) and three more entities.
The Rice Straw Biogas Hub (RSBH) project also involves Straw Innovations Ltd., Koolmill Systems and Aston University in the United Kingdom.
SEARCA Center Director Glenn Gregorio said this groundbreaking collaborative project aims to significantly reduce greenhouse gases (GHG) by transforming agricultural rice production residue and straw into clean energy resources such as biogas through cutting-edge technologies.
According to SEARCA, the project will help reduce 300 million–400 million tons of rice straws, or "dayami," burned every year across Asia, which is a source of GHG.
It cited a Philippine Rice Research Institute report in 2016 showing that 70 percent of rice farmers in the Philippines burned rice straws despite the environmental laws prohibiting the improper disposal of such wastes. The laws include the Solid Waste Management Act of 2000 (Republic Act 9003) and the Clean Air Act of 1999 (RA 8749).
"The RSBH project, beyond introducing advanced technological development, emphasizes understanding the farmers' viewpoints and involving them as crucial partners in the global fight against climate change," Gregorio said.
Biogas can also be an alternative to liquefied petroleum gas and other fossil-based energy sources commonly used for household cooking.
Earlier this year, the Emerging Innovation for Growth Department (EIGD) of SEARCA conducted a two-day event, "Training on Biogas Production from Agricultural Wastes," focusing on imparting the technical know-how of converting and utilizing rice straw and other agricultural wastes into useful energy.
Participated by 19 agricultural officers and lead farmers from Laguna and Nueva Ecija, the training included lectures at SEARCA's Umali Auditorium in Laguna and practical and hands-on sessions on biogas production at the Pacwood Site's biogas facility in Tunasan, Muntinlupa.
During the training, Nur Azura Binti Adam, SEARCA deputy director for programs, highlighted the economic uses of rice straw, stating that "burning dayami is burning money."
SEARCA EIGD program head Eric Reynoso also gave an overview of the RSBH initiative and introduced the center's role in analyzing the rice value chain from pre-planting to marketing and creating an enabling environment to improve rice straw management.
In his lecture, a biogas expert, Victor Luis Jr., explained that converting rice straw into renewable energy anaerobically or without oxygen is possible, citing the use of acid- and methane-forming microbes.
In an interactive discussion of how different anaerobic digesters work, Luis said that although any organic material could be a potential substrate, dried leaves such as rice straws are among the raw materials that can produce burnable biogas.
Viable digester model from Vietnam
Ngo Thí Thanh Truc, Faculty of Environment and Resource Economics deputy head in the School of Economics at Can Tho University in Vietnam, presented her team's farmer-friendly digester utilizing rice straw and water hyacinth as inputs.
She said the university's digester model, made from high-density polyethylene or HDPE and called Subprom, can potentially replace digesters made from concrete and plastic.
Truc said that Subprom requires low maintenance, has been proven more sustainable, and costs just a little more than $400, with a lifespan of up to 15 years.
She said this is unlike common digesters that need animal manure from cows or swine because Subprom digesters can run up to two months with hyacinth and rice straw as feedstocks.
"This is an impressive innovation, especially for households that own less than three swine or none," said Truc, adding that Subprom digesters are being adopted by Vietnam's Ministry of Agriculture and Development.
Along with EIGD program specialist Lichelle Dara Carlos, Luis suggested partnering with Truc's team to introduce Subprom digesters to the Philippines.
Looking at Muntinlupa's model
At Tunasan, the RSBH team and the participants from Nueva Ecija and Laguna learned more about the biogas conversion process through the waste management initiative of the city's Environmental Sanitation Center (ESC).
Engineer Vincent Alon, Muntinlupa's ESC Solid Waste Management Division head, demonstrated the city's waste segregation and management initiatives.
In essence, Muntinlupa's initiative to attain a circular economy also includes using kitchen, market, and sometimes industrial and agricultural wastes for the consumption of animals and as feedstock for its portable digester.
Specifically, feedstocks and animal manure are converted to biogas that can be used for cooking, while the digestate can be turned into compost or fertilizers for use in vegetable or horticultural gardening. Its 1-cubic meter biogas digester undergoing pilot testing was designed by the Department of Science and Technology's Industrial Technology Development Institute (DoST-ITDI).
"The digester can process 210 kilograms of the substrate into methane, fueling half an hour of cooking," said David Herrera, DoST-ITDI senior engineer.
