Avaliação de coagulante orgânica como substituição do sulfato de alumínio no tratamento de água em ETA

Abstract

To improve the quality of water existing in nature, it is necessary to carry out physical and chemical processes, making it suitable for the collective supply of the city. The coagulation process plays an important role in terms of water quality. Generally, water treatment plants use inorganic coagulants containing iron salts in their composition. and aluminum that produce waste. This waste produced by the coagulant contain a high concentration of metals, causing environmental impacts resulting from inadequate final destination. An alternative to this problem is the use of organic coagulants that are biodegradable, non-toxic and reduce the concentration of metals present in the sludge. Therefore, the purpose of this work is to apply an organic coagulant, called Tanfloc – SG, as a possibility to replace the inorganic coagulant Aluminum Sulfate in the stages of coagulation/flocculation/sedimentation in the water treatment plant, located in the municipality of Candiota-RS. The aforementioned ETA is responsible for supplying the Dario Lassance neighborhood. The parameters evaluated for raw and treated water using the Tanfloc coagulants – SG and Aluminum Sulfate were turbidity, dissolved oxygen, electrical conductivity, total dissolved solids, alkalinity, chlorides, total hardness and pH. In the results for the turbidity parameter, it was found that the most effective dosage for removal was 40 mg/L for both coagulants. There was an increase in oxygen when compared to the raw sample due to analytical errors. For electrical conductivity, there was an increase as the concentration of the Aluminum Sulfate coagulant increased, it was also observed that the conductivity did not undergo major changes when the Tanfloc – SG organic coagulant was applied. In the total dissolved solids, it was observed that the application of Aluminum Sulfate as a coagulant resulted in an increase in the parameter. Alkalinity did not suffer great changes when using the Tanfloc – SG coagulant, there was only a slight decrease in the parameter with the increase in the dosage of the inorganic aluminum sulfate coagulant. The results described for total hardness remained unchanged when compared to the total hardness value found in raw water. The pH of the water treated with the Tanfloc – SG coagulant reached a value of 6, remaining practically unchanged when compared to the initial pH. However, for Aluminum Sulfate, a decrease in the pH of the sample was noticed as the dosage increased.