Avaliação da sustentabilidade do reuso da água dos condensadores barométricos com recurso às torres de resfriamento (estudo de caso: Tongaat Hulett: Açucareira de Moçambique, SA–Mafambisse)

Abstract

This work is the result of a professional internship at the company Tongaat Hulett: Açucareira de Moçambique, SA, an industrial unit in the food sector dedicated to sugar production in Mafambisse, in the district of Dondo, Sofala province. There is a significant consumption of water in the operation of the unit for the various operational needs of the equipment, and this water is finally discharged into the Púnguè River at a high temperature, with environmental consequences. It was in this context that the need arose to study the sustainability of available water resources, and the subject was proposed, the aim of which is to assess the impact of reusing effluent from barometric condensers with the installation of cooling towers to save fresh water consumption and reduce its discharge into the receiving environment. The methodology used in this work consists of a literature review, exploratory research, a case study and practical trials, culminating in this report. The water was characterized in terms of its physical and chemical parameters and also quantified. It was found to comply with the quality parameters for operations, with the exception of TSS and temperature. The study also found that the water discharged into the river is 10 °C above the legal limit, at a flow rate of around 1350 m3/h from the barometric condensers, resulting in serious environmental repercussions, making it imperative to make adjustments to its properties before discharging it into the receiving environment. In addition, it was found that the implementation of cooling towers is a solution for integrating the processes, the project of which would require an investment of approximately MZN 17,000,000.00, which can be amortized over 12 years, providing notable benefits in terms of reducing industrial abstraction and discharges, as well as energy savings of around 835 kW.