This study aims to assess water footprint of ethanol production from molasses in Kanchanaburi and Suphanburi Provinces of Thailand, based on the water footprint concept methodology.

The water footprint of ethanol from molasses can be calculated into three parts: sugar cane, molasses, and ethanol production. The green, blue, and grey water footprints of ethanol production from molasses in the Kanchanaburi Province are 849.7, 209.6, and 45.0 (m3/ton), respectively, whereas those of ethanol in the Suphanburi Province are 708.3, 102.9, and 64.8 (m3/ton), respectively. Study results depend on several factors such as climate, soil, and planting date. These are related and effective to the size of water footprint. Especially, if schedule of planting and harvest date are different, which causes the volume of rainfall to be different; these affect the size of water footprints. A limitation of calculation of grey water footprint from crop process has been based on a consideration rate of nitrogen only. Both provinces in the study area have their respective amount of the grey water footprint of molasses, and ethanol production is zero. The wastewater in molasses and ethanol production have a very high temperature and BOD, whereas the grey water footprint in this study is zero because the wastewater may be stored in pond, or it may be reused in area of factory and does not have a direct discharge into the water system. However, there is a risk for soil and ground water pollution.