Aplicação de coagulante, de origem vegetal, como alternativa no tratamento de efluentes em uma indústria de saneantes

Abstract

The use of coagulant based on aluminum sulfate, together with the flocculant, is an input often used in wastewater treatment, however, as a byproduct, it originates the chemical sludge, containing aluminum salts, which carry with them, a polluting character to the environment. Therefore, the purpose of this study is to evaluate the performance of the tannin-based coagulant, which are biodegradable phenolic molecules extracted from the bark of the Black wattle plant, and apply it to an effluent from a sanitizing industry, through tests in Jar Test. The two initial treatments were performed in the same proportion, both for aluminum sulfate and for the vegetable coagulant, at a dosage of 10 g/L, and finally, in the last treatment, it was decided to reduce the concentration of the vegetable coagulant to 2.5 g/L. In view of the results, the vegetal coagulant at 2.5 g/L reduced physical-chemical parameters with percentages of 60.42 % of turbidity, 70.96 % of phosphorus and 97.95 % of anionic surfactants. Besides having completely eliminated animal and vegetable oils and grease and total suspended solids and, additionally, generating an aluminum-free sludge. The choice of this coagulant does not require pH adjustment in the effluent, it acts both in the coagulation and flocculation process, and it is not necessary to use additional products such as flocculants and alkalinizers, besides presenting better performance in smaller dosages, when compared to aluminum sulfate. Therefore, there is viability in opting for the vegetal coagulant, due to its physical-chemical results, its biodegradable composition and for not requiring high investments or changes in existing projects. [resumo fornecido pelo autor]