Coating color wastewater treatment method in coated paper manufacturing process of paper mill

摘要

PURPOSE:To treat efficiently a coating color waste water regardless of influence by its generating source and amount by mixing waste water after chlorination with bleaching sulfate pulp with an ordinary subject waste water, separating an aggregate formed at a specified pH value and then biologically treating the supernatant. CONSTITUTION:An ordinary coating color waste water 1 is mixed with waste water 2 after chlorination with bleaching sulfate pulp in a mixing tank 3, and the pH is adjusted to 1.8-4.5. The mixed liquid 4 is separated into supernatant water 6 and an aggregate 12 in a settling tank 5. The pH of the supernatant water 6 is adjusted by a pH adjusting agent 8 such as calcium hydroxide in a pH adjusting tank 7 for the purpose of being turned into a neutralized pH suitable for biological treatment, and then transferred to biological treatment process 9. Thus, treated water 10 from which COD and BOD components such as starch and polyvinyl alcohol difficult to be aggregated are efficiently removed is formed.