Colour removal from pulp and paper mill effluent using waste products

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "dejavu="" sans";mso-hansi-theme-font:minor-latin;mso-bidi-font-family:mangal;="" mso-bidi-theme-font:minor-bidi;color:#00000a;mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">In this work, different streams of effluents of the Nagaon Papar mill, a unit of The HPC Limited, have been treated with <i>in situ</i>, generated waste products to remove colour due to lignin and its derivatives. The waste products-were hypo sludge (HS) from the hypo-generation unit, alum sludge (AS) from the alum unit and waste bamboo dust, which was converted to bamboo dust carbon (BDC). The HS in doses of 0.2 and 0.4 g/L could reduce colour, BOD and COD to the extent of 82 and 94%, 46 and 91%, 36 and 67%, respectively, from the pulp mill effluent stream. The AS with a dose of 15 g/L was effective in reducing colour, BOD and COD from the extraction backwater stream by 96, 88 and 6S%, respectively. The HS treatment was found to have better impact on the combined effluent quality compared to the AS treatment. The BDC was also equally effective in colour removal from the combined effluent stream at acidic <i>p</i>H and a dose of 3.1 g/L could remove as much as 99% colour. The sorption characteristics have been worked out.</span>