Coagulation pretreatment for ultrafiltration of deinking effluents containing flexographic inks

Abstract

This study was carried out to determine the potential of coagulation pretreatment with organic or inorganic coagulants to improve ultrafiltration performance during processing of wash deinking effluents containing flexographic inks. Wash filtrate effluents generated from mixtures of old flexographic and offset newspapers and old magazines were pretreated with a cationic coagulant and alum before ultrafiltration. Membrane performance was assessed from permeate flux, fouling rate, and ease of membrane regeneration. Coagulation pretreatment of wash filtrate effluents with a commercial cationic coagulant or alum significantly improved ultrafiltration and reduced fouling up to a coagulant concentration of 10 mg/L. Addition of an excessive amount of a cationic coagulant had a very detrimental effect on membrane performance. Alum had a better effect on permeation rate with less fouling tendency compared to the cationic coagulant studied. The methods of analysis used to determine dissolved and colloidal substances removals were not sensitive enough to establish a correlation between substance removal and ultra-filtration performance.

Citation

Chabot, Bruno; Krishnagopalan, Gopal A.; Abubakr, Said. 1999. Coagulation pretreatment for ultrafiltration of deinking effluents containing flexographic inks. Progress in paper recycling. (Nov. 1999): Pages 46-55