Preliminary Research on Removal of Organic Substances Contained in Wastewater from Plastic Lenses Production

More than 80 percent of all eyeglasses worn today have plastic lenses. Plastic lenses made of polycarbonate discs are created through the process of machining which requires the use of a coolant. During the production process, the rotating disc and blade are poured with a mixture of water and synthetic coolant to remove the resulting chips and cool the blade and discs. The ensuing wastewater contains chips, water and coolant. The chips are separated by filtration and the water and coolant are returned to the machine tool. Due to the low particle weight some of the plastic dust flotates easily and creates foam. If there is too much foamed dust, a skimmer is added. In order to avoid machine damage and product quality deterioration, the mixture in circulation is changed every 24 hours. This mixture is wastewater with a high COD value of 11 200 - 20800 mg/L, a turbidity of 260-870 NTU, and a colour of about 200 mg/L. For their treatment, a coagulation process using mainly aluminum coagulants and advanced oxidation processes (AOPs) used of Fenton reagents were applied.