CHEMICAL ENGINEERING TRANSACTIONS VOL. 74, 2019 A publication of The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Sauro Pierucci, Jiří Jaromír Klemeš, Laura Piazza Copyright © 2019, AIDIC Servizi S.r.l. I SBN 978-88-95608-71-6; I SSN 2283-9216 Cassava Wastewater Treatment by Coagulation/Flocculation Using Moringa oleifera Seeds Ana Paula Trevisan a *, Eduardo B. Lied b , Fábio L. Fronza b , Kauanna U. Devens a , Simone D. Gomes a a Western Parana State University, Agricultural Engineering Graduate Program, Laboratory of Biological Reactors, Rua Universitária, 2069, Jardim Universitário, 85.819-110, Cascavel, Paraná, Brazil b Federal University of Technology Parana, Department of Biological and Environmental Sciences, Avenida Brasil, 4232, Medianeira, Paraná, Brazil anapaullatrevisan@gmail.com The present study evaluated the efficiency of starch wastewater treatment through coagulation/flocculation using extracts of Moringa oleifera (M.O.) seeds as a natural coagulant. The experiments were performed following a Rotatable Central Composite Design (RCCD). The studied variables were: M.O. concentration and sodium chloride (NaCl) solution concentration. The response variables analysed were: Turbidity, Apparent Colour, COD and Cyanide Ion. The operational conditions optimized by the statistical program were: M.O. concentration of 2,484 mg L -1 and saline concentration of 0.9 mol L -1 . Under these conditions the removal estimates are 89.16 % (turbidity), 54.43 % (apparent colour), 66.39 % (COD) and 9.9 % (cyanide ion). 1. Introduction Cassava processing industries, especially those producing starch, have a high polluting potential due to the release of their effluents. Among the main characteristics of this effluent is the high organic load and the presence of cyanide ion, a constituent with high toxic potential. Farms effluents treatments had been done predominantly by systems that use biological mechanisms (Kuczman et al., 2017; Carvalho et al., 2017). However, biological treatment systems present limitations for effluents containing cyanide, as is the case of starch wastewater. Among all plant materials that have been tested over the last few years (Padilha et al., 2013; Jun and Ahmad, 2015; Wolf et al., 2015; Camacho et al., 2015; Teh and Wu, 2014; Daza et al., 2016), the extract obtained from Moringa oleifera seeds has shown itself to be one of the most effective as a primary coagulant for wastewater treatment, and it can be compared with conventional coagulants such as those derived from aluminium salts (Bongiovani et al., 2015; Amagloh & Benang, 2009; Lédo et al., 2009; Noor et al., 2018; Ndabigengesere and Narasiah,1998). There are several studies in the literature that investigate the use potentials of this seed. Prasad (2009) investigated the effects of the dosage, pH and salt concentration for Moringa oleifera seed coagulant extraction, for optimization purposes, for colour removal process of distillery effluents. Lédo et al. (2009) investigated the efficiency of two coagulants, aluminium sulphate and Moringa oleifera seeds, for turbidity removal in water samples of low turbidity. Due to certain characteristics of starch wastewater, such as high turbidity, colour and colloidal organic matter, the adoption of coagulation/flocculation techniques has become a practice that allows to obtain excellent results, as will be presented throughout the study. 2. Material and methods 2.1 Samples Physicochemical Characterization The effluent samples used in this study were collected in Zadimel Amidos, which is located in Concordia do Oeste district, in the city of Toledo, Paraná, Brazil. In order to characterize the effluent, the following DOI: 10.3303/CET1974062 Paper Received: 23 July 2018; Revised: 30 October 2018; Accepted: 22 March 2019 Please cite this article as: Trevisan A.P., Lied E., Fronza F.L., Devens K., Gomes S., 2019, Cassava Wastewater Treatment by Coagulation/flocculation Using Moringa Oleifera Seeds, Chemical Engineering Transactions, 74, 367-372 DOI:10.3303/CET1974062 367