Turn waste into energy
Green rice fields, lush tomato beds, firmly rolled cabbage or lush green water spinach beds at the Vietnam National University of Agriculture are telling a special story about the journey of turning waste into resources. The nutritional source for these crops can start from things that seem to be only discardable: leftover food, organic waste or livestock waste.
Waste is put into the methane fermentation system. Biogas generated during the process of microorganisms breaking down organic matter can be used to generate electricity or heat. The remaining organic matter after fermentation can continue to be used as fertilizer, bringing nutrients back to the soil.
At the Vietnam National University of Agriculture, organic products after treatment from the CT-1000 system have been tested on four crops including rice, tomatoes, cabbage and water spinach. A cycle from waste to energy, then back to soil and crops is being tested right in actual conditions in Vietnam.
This is one of the results of a cooperation project between Vietnam National University of Agriculture, Japan International Cooperation Agency (JICA) and the Joint Venture of Toyo Fujiko Co., Ltd., Toyo Energy Solution Co., Ltd.
The project was implemented from May 2022 to December 2026 to test methane fermentation technology for organic waste in Vietnam.
Assoc. Prof. Dr. Vu Ngoc Huyen - Deputy Director of Vietnam National University of Agriculture - said that the project is being implemented in the context of Vietnam promoting green transformation, towards the goal of net zero emissions by 2050.
Within the framework of the project, the BMP bio-methane gas generation potential assessment system and the CT-1000 continuous fermentation testing system were put into use at the Vietnam National University of Agriculture. The parties assessed the methane gas generation capacity of four groups of raw materials including chicken manure, pig manure, leftover food and organic waste.
Notably, the CT-1000 system has been operated with a treatment capacity of 30kg of waste per day. Organic products after treatment from this system are tested on rice, tomatoes, cabbage and water spinach, creating a practical basis for assessing the ability to use as fertilizer in agricultural production.
Methane fermentation is a technology that uses microorganisms to break down organic matter in oxygen-free conditions, creating biogas. This gas can be used as fuel for boilers or generators, providing heat and electricity.
This technology has been applied in many countries, especially in Europe. In Japan, there are currently about 300 facilities operating under the methane fermentation model.
Ms. Nishimura Emiko - Deputy Chief Representative of JICA Office in Vietnam - said that methane fermentation technology can convert waste into biogas to create energy, while creating products for agricultural production.
Within the framework of the project, JICA also supports training lecturers of the Vietnam National University of Agriculture in Japan in technology, facility management, maintenance and operation. Small-scale BMP equipment and demonstration systems after being transferred can continue to serve research, training and technology dissemination.
Renewable energy sources are exploited on the spot
The evaluation results show that the ability to create methane and recover energy varies depending on the type of waste. According to Mr. Kazuya Matsunaga - Head of Technical Department, project technical department, Toyo Energy Solution Co., Ltd. - leftover food has the highest methane generation capacity among the four types of raw materials evaluated. Organic waste also has high energy recovery potential.
Meanwhile, pig manure, if treated separately, creates a lower amount of methane, so it can be mixed with other materials to increase efficiency. With a simulated power generation efficiency of 35% and a heat recovery efficiency of 50%, treating one ton of food waste can generate about 318kWh of electricity and recover 454kWh of heat.
With the same volume of raw materials, the estimated electricity output from pig manure is 64kWh, chicken manure 276kWh and organic waste 212kWh.
The above figures are the estimated results of the potential for energy recovery from each type of raw material, showing that organic waste is not only a problem to be addressed but can also become a renewable energy source exploited on the spot.
However, one of the current difficulties is that the regulations and licensing mechanisms suitable for methane fermentation technology in Vietnam have not been fully developed.
While Europe and Japan have relatively complete legal systems for this field, Vietnam needs to continue to improve institutions and legal corridors from central to local levels to create conditions for technology to be popularized and applied.
