The water footprint of the sugarcane agro-industry in the Northeast region of Brazil

Abstract

The water footprint (WF) is an important indicator for water management, as it identifies the amount of water used directly and indirectly by a consumer or a product. The objective of this study is to analyze the sugarcane industry's WF in Brazil's Northeast region for the 2016/17 and 2017/18 harvest seasons. The blue, green and grey WFs of sugarcane were quantified, as well as the blue WFs of the production processes of ethanol and sugar, the main subproducts of sugarcane for both harvests. The work was carried out in an area with 18.42 hectares of sugarcane crops under sprinkler irrigation. The process of sugarcane production and use of pesticides was surveyed and meteorological data for the production period was collected. Right after, mathematical models were used to estimate the blue, green and grey WFs. The WF of the sugarcane was found to be 2,364.87 m³ t-1 and 1,043.92 m³ t-1 for the first and second harvest, respectively. The grey WF made up the largest part of this value, mostly due to use of the pesticides Diuron 800 and Imazapic. The processes of ethanol and sugar production, meanwhile, were found to have a blue WF of approximately 10 m³ t-1 and 5 m³ t-1, respectively. From these results, we can conclude that the WF is an effective indicator for monitoring water use in the production cycle of sugarcane and its subproducts, and that the use of fewer polluting pesticides would aid in reducing the WF of this cycle.