ELIMINATION OF SUSPENDED MATERIALS IN CONTAMINATED EFFLUENTS FROM CARDBOARD RECYCLING PLANTS

摘要

The wastewater, from a paper plant whose raw material is recycled cardboard, was treated with different types of polyelectrolytes as coagulation-flocculation agents, to reduce contamination levels as measured by the parameters turbidity, suspended solids (SS) and chemical oxygen demand (COD). Different anionic polyelectroloytes were tested, including polyacrylamide in emulsion and potassium acrylate silicate ester, as well as different cationic polyelectrolites such as combinations of cationic polyacrylamide of various molecular weights with quaternary ammonium compounds in various ratios; polyacrylamides in emulsion; and quaternary ammonium compounds, including the EPI chlorhydrin diemthlamine. The investigation was carried out following a compete factorial experimental design with three variables at two levels (2~3). The polyelectrolyte concentration was the most important variable in the process for eliminating suspended particles. Therefore the results obtained with each coagulation-flocculation agent were evaluated in terms of the polyelectrolyte concentration parameter.