COMMERCIAL COAGULANTS EFFICACY ASSESSMENT FOR USE IN WATER TREATMENT SYSTEMS

Abstract

The great variety of coagulants allows for the Water Treatment Stations to seek the best cost-benefit reagent for removing turbidity of raw water. The main objectives of this paper are to study the efficacy of turbidity removal of water captured during drought periods, using Poly Aluminum Chloride (PAC) and Tanfloc-SL as coagulants, and to create a study concerning their economic viability considering expenditures with coagulation and disinfection. Their efficacy was determined through coagulation diagrams. After the coagulation, some samples were filtered and dosed with a batch of disinfectant. PAC maximum efficiency was 94% in pH 7 and dosage 28 ppm. Tanfloc-SL maximum efficiency was 92% in pH 6.95 and dosage 17 ppm. When the necessary dosages for removal of 90 % of the initial turbidity are compared, the Tanfloc-SL expenditure was 54% smaller than the PAC one. The chlorine consumption was 23.58% higher when the Tanfloc-SL was chosen as the coagulant. Replacing PAC by Tanfloc-SL, an economy of 49.61% will be achieved.

Keywords

• Diagrama de coagulação
• Jar test
• PAC
• Tanfloc-SL
• Análise econômica.