Study of flocculation with PONILIT GT-2 anionic polyelectrolyte applied into a chemical wastewater treatment

摘要

This paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte in conjuction with ferric sulfate in a chemical wastewater treatment viz.wastewater from ceramics manufacturing.Synthetic wastewaters with different colloid concentrations were prepared and the coagulation-flocculation process followed by sedimentation and/or filtration was studied.Variables associated with the chemical wastewater composition,mixing time,and the coagulant and flocculant dose are considered in order to appreciate the process effciency in terms of turbidity,chemical oxygen demand (COD),and color removal.The degrees are higher for turbidity and color(>80%)removal respectively, and,satisfactory for COD(<50%).An empirical model was elaborated by a third order rotatable design 2~3 type,considering ferric sulfate dose,polyelectrolyte dose,and mixing time as independent variables, while the turbidity and color removal effciencies were chosen as optimization criteria.The empirical model was found adequate for the chemical wastewater treatment.Also,an analysis of the model was performed to find the optimal operating conditions,in order to apply this process for an effcient chemical wastewater treatment using ferric sulfate as coagulation agent and PONILIT GT-2 anionic polyelectrolyte as flocculation agent.The optimal values correspond to a ferric ions concentration of 6.093 mg/L,a polyelectrolyte dose of 0.651 mg/L,and a mixing time of 24.024 minutes for turbidity removal(95.869%),respectively,and,to a ferric ions concentration of 6.01 mg/L,a polyelectrolyte dose of 0.69 mg/L,and a mixing time of 26 minutes for color removal(98.741%).