Water Footprint as an Emerging Environmental Tool for Assessing Sustainable Water Use of the Bioethanol Distillery at Metahara Sugarcane Farm, Oromiya Region, Ethiopia

Abstract

In Ethiopia, sugarcane estate farms and bioethanol distilleries are being expanded at an alarming rate to provide alternative sustainable energy as renewable, affordable, and low carbon footprint bioenergy for the transportation sector. The promotion of bioethanol production is definitely poised to cause high competition for water resources. Thus, the aim of this study was to investigate the water footprint (WF) of sugarcane molasses-based bioethanol production of the Metahara sugarcane farm. Ten years of meteorological data (2007–2016) were collected from the Metahara weather stations and processed through the CROPWAT 8 model using the Penman-Monteith method. Sugarcane coefficient (K c ) was taken from FAO data; and sugarcane growing seasons, fertilizer application rates, sugarcane yield, and factory data were obtained from the Metahara factories. Reference evapotranspiration varied from 4.73 to 7.98 mm/day whereas effective rainfall (R eff) values ranged from 256.4 to 743.6 mm/growing season of sugarcane (16 months). The estimated sugarcane water requirement (SWR) ranged from 2544.1 to 4833.3 mm/growing season. The ANOVA test (p > 0.05) for R eff showed statistically insignificant differences in means but the test for SWR (p < 0.05) revealed a statistically significant differences in means. The average sugarcane WF was 217.69 m3/t whereas the bioethanol WF was 3106.7 L/L. Hence, the WF of bioethanol production in the Metahara distillery is higher than the global average, indicating pressure on local water resources. Therefore, the results of this study may help policy makers to develop appropriate water resource management for the extensively growing sugar and bioethanol industries in Ethiopia.