CARACTERIZAÇÃO DA ÁGUA RESIDUAL DE PRODUÇÃO DE BIODIESEL PARA USO NA IRRIGAÇÃO DE CULTURA DE GIRASSOL

Abstract

Fuel can be obtained from vegetable oils, animal fats or waste products such as frying oil already used. Biofuel production consists of the transesterification reaction of an oil with a short chain alcohol, which results in the oil (Biodiesel) together with glycerine as a byproduct, which is separated by decantation. To purify the end product of this reaction, a slightly acidified water wash is performed to remove certain impurities from the oil. This water is called wastewater because it contains a high amount of polluting materials which pose a threat to public health and the environment. Thus, this waste water should not be disposed of without proper treatment. Among several ways of disposal for wastewater is reuse for irrigation, because these waters may contain nutrients essential to plant development. The objective of this work was to evaluate the indicators of water quality from biodiesel washing. The parameters for sunflower crop irrigation were evaluated because it is a crop resistant to various climates, temperatures and a higher yielding oilseed for biodiesel production. Indicators for water analysis were pH, temperature, conductivity, alkalinity and acidity, dissolved oxygen (DO), carbon dioxide (CO2), nitrates, total hardness, calcium and magnesium hardness, chlorides, turbidity, sodium (Na), potassium (K) and lithium (Li) of which dissolved oxygen, acidity, pH and conductivity. From the results obtained, for the analyzed water to be within the irrigation standards only corrections of some parameters were necessary: adjustment of pH, being possible to carry out studies with diluted proportions of this residual water; perform nitrate quantification and; reduction of the amount of lithium ion.