Avaliação do processo de coagulação/floculação para tratamento de água potável de manancial superficial

Abstract

Water is an essential resource for life in earth, and its consumption is one of the main human needs, and for that, it must have a good quality. In order to have a good quality water supply, regulations establish drinking standards, expressed through minimum parameters that must be complied by the companies that produce drinking water. In order to meet these standards, especially in waters abstracted from surface sources, the application of a suitable and properly optimized treatment process is necessary. Within this context, this work aimed to optimize the operational parameters of the conventional treatment process for treatment of water of the Clarimundo River, located in the municipality of Cerro Largo, State of Rio Grande do Sul. In a Jar Test bench system, the parameters pH, coagulant dosage and sedimentation time were investigated in the reduction of color and turbidity, for the coagulants aluminum sulphate and ferric chloride. The best operation condition of the process were pH 7.3, coagulant dosage 6.67 mg L-1 and sedimentation time 60 min for the coagulant aluminum sulphate and pH 7.1, coagulant dosage 4.59 mg L-1 and sedimentation time 60 min for the coagulant ferric chloride. Under these conditions, significant removals of the investigated parameters were obtained, wherein the final values attained of color and turbidity using aluminum sulphate comply drinking standards stablished by the Brazilian regulation.