Development of environmental sustainability for the biodiesel industry in Thailand

Abstract

The Thai Government has committed to promoting the production and use of biodiesel in place of petro-diesel oil, with the objective of reducing the country's dependence on imported oil. However, biodiesel production generates large amounts of waste and wastewater. This research aspires to adopt industrial ecology measures to alleviate environmental problems encountered in the biodiesel industry in Thailand. The proposed implementation options included clean technology and waste exchange measures. Five biodiesel production factories were selected to analyse material flow and balance in the production processes. The results show that 1 m³ biodiesel production generated 8 kg of spent bleaching earth, 140 kg of glycerine and 0.50 m³ of wastewater with a chemical oxygen demand (COD) content of up to 170,000 mg/L. The postulated options, on the basis of clean technology, included methanol recovery from the methyl ester and glycerine mixture, substitution of the hydroxide catalyst by methoxide, and reuse of the final washing water used in the methyl ester purification step. These options are expected to reduce raw material and water use in the production processes. The wastes or by-products generated from the biodiesel production process can be utilised as raw material for other industries. Crude glycerine, which is produced in large quantities from the trans-esterification process, can be reused or recycled by a value-added conversion for other industries. In addition, the biodiesel wastewater mostly obtained from the methyl ester washing process can be treated in an anaerobic digestion system to produce biogas for electricity generation.

Keywords:

• biodiesel
• industrial ecosystem
• clean technology
• waste exchange
• glycerine

Acknowledgements

The authors appreciate the cooperation of all study biodiesel production factories. The authors also thank the International Post-graduate Programme in Environmental Management (Hazardous Waste Management) of Chulalongkorn University, Thailand, for financial support.