One of the ways of polymer waste management is its chemical modification. Waste polystyrene foam (EPS) and virgin polystyrene (VPS) as a reference material were converted into polymeric flocculants by chemical reactions. Poly(styrene sulphonate) acids (EPSS and VPSS) were obtained from EPS and VPS during the sulphonation process with sulphuric acid as the sulphonating agent and Ag 2 SO 4 as the catalyst. Products were precipitated in the form of sodium salt (NaEPSS, NaVPSS) in the reaction with Na 2 CO 3 . The influence of temperature and the time of reaction on the properties of the products were studied.Products with determined molecular weight and number of sulphonic group per monomer units were divided into several fractions by fractional precipitation with 0.5M aqueous NaOH as the solvent and 2-propanol as the precipitant.The products were successfully used as flocculants in the treatment of the waste water discharge model colloid system, iron (III) hydroxide, which is comparable with industrial waste and water from mining companies and galvanising plants. The application of the obtained products caused a significant decrease in turbidity of the studied solutions. It was also found that the effectiveness of the flocculation depends on the number of sulphonic groups per monomer unit and the molecular weight of the polyelectrolytes.