TREATING METHOD FOR RICE CLEANSING WASTE WATER

摘要

PURPOSE:To treat the waste water of a high concn. resulting from rice cleansing without dilution and reduce the amt. of water to be treated and the volume of a waste liq. tank to the least possible extent by a method wherein calcium chloride is added to the rice cleansing waste water having SS value not less than a specific value and substances in suspension are coagulated to be separated from the waste water. CONSTITUTION:Calcium chloride is added to the waste water having SS value of at least 1,000ppm resulting from rice cleansing and substances in suspension are then coagulated to be separated from the waste water. The rice starch mixed therein in a colloidal form is coagulated and precipitated by the action of calcium chloride and the supernatant liq. becomes transparent. Since this method can increase the rate of coagulating sedimentation and reduce the size of a stirring tank and of a settling tank and since the supernatant liq. treated with calcium chloride is much lower in SS and BOD value than the original waste water, there is no need for aq. diluent and the volume of equipment can be reduced.