Eficiência do sulfato de alumínio e cloreto férrico em ensaio de coagulação e floculação para efluentes de uma indústria de sorvetes e açaís

Abstract

This study highlighted the importance of treating industrial effluents, such as those generated by ice cream and açaí manufacturers, in order to reduce environmental impacts and ensure compliance with CONAMA Resolution No. 430. Physicochemical treatments are commonly applied either alone or in combination with other technologies in wastewater treatment plants (WWTPs) for the treatment of residual water.Accordingly, the efficiency of two inorganic coagulants—aluminum sulfate and ferric chloride—was evaluated through coagulation-flocculation tests (jar test) conducted with raw effluent samples from an açaí and ice cream industry, aiming to assess the reduction of turbidity and determine the optimal conditions for each coagulant.Since the raw effluent had an initial pH of 3.4, which is outside the ideal working range for the coagulants, a pH adjustment was performed by adding 2 mL of NaOH, raising the pH of the sample to 6.15 to improve coagulant performance during the tests. For the sample with an initial turbidity of 1050 NTU, variable concentrations of aluminum sulfate (0.050 to 0.325 g/L) were applied, while for another sample, with 2090 NTU, ferric chloride was used at concentrations ranging from 0.250 to 1.625 g/L.The results showed that the concentration of 0.325 g/L of aluminum sulfate led to a turbidity reduction of up to 81.76%, whereas the application of 0.750 g/L of ferric chloride resulted in a 74.64% reduction.