Treatability of water-based printing ink wastewater using electric arc furnace dust

Abstract

Water-based inks have been used widely in all of flexographic printing and successfully help reducing volatile organic compound (VOC) emission and hazardous waste from printing industry. However, water-based inks generate a new concern as their wastewater is highly colored by the pigment even at the low level concentration. In addition, resins-binders and some additives composed in inks cause contamination with organic materials. The traditional methods for color and organic substances (referred as COD) removals from various wastewaters mostly comprise of physic-chemical method, adsorption and advanced chemical oxidation processes. In this context. The experimental study focusses the treatability of effluents generated from a water-based ink industry by using electric arc furnace (EAF) dust. The adsorption by EAF dust is expected to be the principle mechanism of treatment. The optimum condition, therefore, was investigated by variations of EAF dust dosages in the range of 0 to 50 g/l, pH of 5 to 8, and mixing times of 5 to 30 min. The results showed that pH played a significant role in both color and COD removals. Under acidic condition the addition of EAF dust and increase of mixing time did not enhance the treatabilly. In the experiment at pH5.2 the removal efficiencies of color, COD and SS were as high as 99% 87 and 98%, respectively without EAF dust adddition In case of neutral pH level (the pH range of wastewar itself). The increase of EAF dust dosages room 0 to 50g/1 significantly affected the treatability while the effect of mixing times was little. The maximum removal efficiencies of color, COD, and SS were 99%, 88% and 97%, respectively, when using EAF dust dosage of 40g/l with mixing time of 5 min