Water Use and Impacts Due Ethanol Production in Brazil

Ethanol production from sugar cane crops uses significant amount of water in the agricultural and industrial processing phases. Most of the sugar cane plantations in Brazil rely on natural irrigation complemented by partial fertiirrigation, carried out mainly to manage water wastes, limiting their production to regions where reasonable rainfall index occurs. Sugar cane processing to ethanol uses water collected mainly from surface water flows and, in few cases, from underground natural reservoirs for many different activities and it become contaminated with organic and inorganic pollutants. The paper describes agricultural and industrial activities involved in ethanol production trying to quantify the amount of potential pollutants that are sources of water contamination and provides description of measures commonly used to mitigate such contamination and the ones used to clean waste water. Waste water quality returned to soil and to surface water flows is regulated by the government and
such regulations are properly described and discussed. Suggestions on how to improve the quality of waste water above the present level imposed by regulation are also discussed. In particular, the main source of water pollution, stillage, is examined in detail as potential source of energy and other products while its intensity of contamination is reduced.