Brine wastewater pretreatment using clay minerals and organoclays as flocculants

Use of conventional pretreatment for pickle industry brine wastewater (BWW) is not efficient due to its low pH, high salt content and high concentrations of suspended and organic matter. The goal of this work was to inspect different clay minerals and berberine-based organoclays as possible flocculants to reduce BWW turbidity, total and volatile suspended solids (TSS and VSS, respectively) and chemical oxygen demand (COD). Preliminary flocculation tests showed Volclay KWK (VO) and Pangel C150 (C150) to be the best candidates for a two-step sedimentation test, with the highest TSS, VSS, COD and turbidity reductions. Adsorption isotherms showed that VO and C150 adsorb different amounts of berberine, and therefore a common reference line for organoclay preparation was based on their point of zero charge. Two-step sedimentation tests showed that combining VO-berberine and VO (organoclay and raw clay, respectively) better reduces the inspected parameters than two steps with VO, whereas the opposite held true for C150-berberine and C150. Out of all treatments, two steps using C150 showed the best TSS, COD and turbidity reduction. C150 appears to be an excellent candidate for a future multistage flocculation and sedimentation processes for BWW treatment.