At Cholcharoen, a tapioca flour manufacturing plant in Chon Buri province, the plant is saving around Bt120,000 each day in fuel oil costs, a key energy source for the plant's manufacturing process, by recycling its waste water into a new energy source.

Instead of using fuel oil to produce tapioca flour, the plant has adopted a new waste-water treatment technology to use all its 24,000 cubic metres of waste water to produce biogas for the production process. The plant has successfully used biogas to totally replace the use of fuel oil.

The plant's chairman Ung Meng Chua said the plant had spent Bt40 million to build a water-treatment system to produce a source of biogas energy. With this, it can save around 40 per cent of its production costs by using the energy produced within the plant.

Built two years ago, the water treatment system at Cholcharoen was made fully operational late last year. Today it can produce 17,600 cubic metres of biogas a day and this is used to produce 200 tonnes of tapioca flour. Normally, Ung said, the plant used around 8,000 litres of fuel oil for the daily production process.

To establish the water-treatment system, the plant received financial support from the Technology Management Centre at the National Science and Technology Development Agency, and the National Energy Policy Office provided a loan at low interest. It also worked with a research team from King Mongkut University of Technology Thonburi (KMUTT) to adopt its 20-year research project in developing an advanced anaerobic waste-water treatment and biogas-production system for use in the plant.

Annop Nopharatana, an engineer of the Centre of Waste Utilisation and Management at KMUTT, who is in the research team, said that the system was developed with anaerobic fixed film reactor (AFFR) technology. As the technology is designed under a closed system, he said it offered higher efficiency in water treatment compared to open-pond type systems currently used in many plants, and more importantly, it yielded biogas.

The concept of this system is to put plastic media inside the reactor on which a consortia of bacteria attach and grow as a slime layer or bio-film. The media is fully submerged and waste water flows around it. As the waste water passes through the media-filled reactor, the attached and suspended anaerobic biomass converts both soluble and particulate organic matter in the water to biogas. He said this technique would offer the plant more convenience in operation, as it did not require complicated maintenance from specialists who supervise the system.

Biogas is regarded as an alternative energy source. It can help as a substitute for fossil fuel sources. As the gas can be produced from waste from agro-industrial production processes, NSTDA also has a plan to encourage local manufacturing plants to adopt the technology to generate their own energy source, and importantly, preserve the environment.

Since the investment in the system requires around Bt40 million to Bt50 million, the agency has worked with six commercial banks to initiate a project to provide soft loans for manufacturing plants which want to implement it. In the first phase, the project will focus on tapioca flour manufacturing plants.

Apart from Cholcharoen, during the past two years, KMUTT's waste-water treatment technology has also been implemented in the three other tapioca flour-manufacturing plants. Cholcharoen is the first complete site to show the technology's proof-of-concept.

Ung added that after all the investment, the plant hoped to break even within seven years, but more important is that it made the plant self-reliant as it can produce energy for use within the plant.

It is being predicted that each year, the country produces 2 million to 2.5 million tonnes of tapioca flour and this would require more than 70 million litres of fuel oil, costing around Bt3.5 billion to Bt4 billion a year. Ung said if manufacturing plants started to use this technology, it would dramatically help the country save costs to buy fuel oil.

Pongpen Sutharoj

The Nation