Patent ID: 7468137
Filing Date: 2008-12-23
Classification: C02F,Y10S

Abstract:
1. A wastewater treatment process for treating wastewater discharged during a process for producing an electrophotographic toner comprising a water-based dispersion containing a surfactant, a colorant, silica and other solid matter, the process comprising: a reaction step of adding a coagulant to the wastewater and conducting a coagulation reaction; a flock formation step of forming a flock from aggregates generated in the coagulation reaction of the reaction step; and a separation step of separating the flock and a separated liquid; wherein: the wastewater is treated using a polysilicato-iron coagulant; a quantity of the polysilicato-iron coagulant added is equivalent to a concentration within a range from about 1 mg/L to about 500 mg/L relative to the wastewater; a temperature of the wastewater during the reaction step is from about 10° C. to about 30° C.; the quantity of the surfactant in the wastewater is within a range from about 0.1 to about 4 weight percent of the weight of the wastewater; and the quantity of silica in the wastewater is within a range from about 0.1 to about 4 weight percent of the weight of the wastewater.