Treatability of waste plastic recycling industry wastewater

In this study, sulfonation was applied to waste polystyrene (PS) and sulfonated PS flocculant (FSPS) was synthesized. The treatability of washing wastewaters of different types of plastics and the effectiveness of synthesized FSPS in this treatment was investigated. The effectiveness of synthesized FSPS in physicochemical treatment of waste plastics (High Density Polyethylene-HDPE, Low Density Polyethylene-LDPE, Polyethylene Terephthalate-PET, Polypropylene-PP, PS and mixed) washing wastewaters was revealed. Alum and FeCl3 coagulants and FSPS and polyelectrolyte (PEL) flocculants were studied. Flocculant dosage and pH were optimized. Washing wastewater composition and optimal treatment conditions vary with type of plastic. Optimum pH and coagulant was determined as 13 and FeCl3 for HDPE washing wastewater while it was 9 and alum for others. Optimum FSPS dosage varies between 5-20 mg/L. Under optimized conditions 94-98% turbidity, 70-92% COD, 86-99% SS and 50-89% oil-grease removal could be achieved.This study indicated that the synthesized flocculant can be used efficiently in wastewater treatment. The study suggested a new solution incorporating recycled plastic product in wastewater treatment. This alternative solution will also contribute solid waste management, through minimization of waste generation by recycling.