Otimização da aplicação combinada de coagulante e polímero no tratamento de água destinada ao processo industrial

Abstract

With the rising demand of the consumption of water and electricity, the importance and relevance of the theme sustainability becomes elicit, which has as objective the conscious consumption of natural resources, especially water, and consequently the processes involved in its treatment for later use. It is proposed to evaluate the different dosages in the combined use of coagulant and Polymer for the removal of water turbidity for industrial purpose. The study was carried out in a non-drinkable water treatment station, situated in a Três Lagoas town – MS. At first, during the month of May 2020, the parameters of treatment process were evaluated, comparing them in sequence to the preset parameters defined by the plant manufacturer. During the month of June, some opportunities to improve the steps of coagulation and flocculation through lab-scale testing using the Jar Test were identified, optimizing the dosages of coagulants and Polymer and adding the implementation of a daily routine of process follow-up. With the obtained results after the Jar Test, it was possible to reduce applications in treatment plant from 20 to 12 mg. L-1 of aluminum sulfate and from 0,45 to 0,3 mg. L-1 of anionic polymer, emphasizing that the efficiency in removing raw water turbidity for lab tests in the previous mentioned dosages keep above 80%. After making the changes in dosages, the mechanism of coagulation applied in the process was evaluated, and it continued as charge neutralization and the bridging flocculation happened, during the whole evaluated period (February to November 2020), changes were applied aiming to meet pre-defined parameters limit for treated water, being: pH between 6 and 8, conductivity below 110 µS.cm-1 and turbidity below 1,0 NTU. The numbers obtained during the month of February to June (before adjustments) kept for were pH between 6,0 and 6,7, conductivity between 61 and 93 µS.cm-1 and turbidity between 0,2 and 0,6 NTU, while during the months of June to November, the numbers kept for pH were between 6,2 and 6,9, conductivity between 59 and 90 µS.cm-1 and turbidity between 0,1 and 0,4 NTU, maintaining themselves in both periods for the different dosages of combined coagulants and polymer within the pre-established limits. With the adequations made in dosages, after the endo f November it was possible to determine the gains with the optimization for each product, being the reduction of 44 tons of coagulants per month (35%) and 300 Kg per month of polymer (25%). Analyzing optimized consume mentioned before, it becomes evident the importance of the optimization and implementation of lab procedures and routine in daily operation, for small changes may bring extraordinary economic and environmental gain for the process.