Removal of Starch Glue from Wastewater by Coupling Coagulation and Electroflotation Processes

Resumo

The aim of the current study is to optimize the treatment of wastewater rich in starch glue issued from the card board industry by coupling coagulation and electroflotation processes. The treatment consists of maximizing the removal rate of suspended solids contained in wastewater. This study includes both batch and continuous modes. In batch mode, a model water solution was used in order to evaluate the influence of pH, current density, and coagulant concentration, which were selected as operating parameters to be optimized. The methodology of experimental research, with an orthogonal central composite plan, was approved. In order to approach the process to the industrial scale and to improve the suspended solids removal rate, a continuous mode was also studied. The purification efficiency consisting in the elimination of suspended solids exceeded 95%. Physicochemical characterization of the effluent was performed before and after the treatment in batch and continuous modes to improve the efficiency of this process. This characterization included pH, conductivity, salinity, chemical oxygen demand, biochemical oxygen demand, and suspended solids.