Comparação de coagulantes utilizados no tratamento de efluentes de uma indústria de café solúvel por meio da avaliação do ciclo de vida simplificada

Abstract

The coffee produced in Brazil represents one-third of the world output, generating effluent with high concentration of organic material and it can cause significant environmental impacts, if released into water bodies without proper treatment. The sewage treatment plants are using coagulating agents which promote clumping of particles in suspension or dissolved, making them larger, and facilitating its removal by filtration and decantation. These coagulants can have inorganic or organic origin which are chosen by industries depending on the technical performance of them. However, seeking to provide support to decision-making processes on the choice of coagulants from the environmental point of view, this paper consists of two stages. The first one presents the survey of the state of the art on the application of Life Cycle Assessment (LCA) in industrial effluents treatment processes, particularly in soluble coffee industry. Thus, a systematic literature review (SLR) was conducted, allowing the collection and evaluation of available studies based on the subject through a sequence of predetermined steps. The results indicate that the tool is effective in decision-making, but in Brazil the studies on the subject are scarce. The second stage promotes the identification of environmental aspects and potential impacts of coagulants, Ferric Chloride and Tannin, in each stage of their life cycle, making use of the Simplified Life Cycle Assessment methodology (SLCA). The development of SLCA was based on the choice of a semi-quantitative method, DfE Matrix, where the obtained result in a survey carried out for each analyzed product is calculated in an array with a maximum score of 125 points. Tannin was the suitable alternative with efficiency of 84% against 68.8% from Ferric Chloride. Regarding the most stunning life cycle stage, the pre-manufacturing was emphasized to both coagulants. As for the environmental aspect more relevant, to the Ferric Chloride was liquid waste, while to the Tannin was the energy consumption.