Studies of Renovation of Pulp Mill Wastewater
Pilot Plant Tests for Granular Activated Carbon Adsorption of Kraft Pulp Mill Wastewater
1973 Volume 27 Issue 11 Pages 543-553
Details
1973 Volume 27 Issue 11 Pages 543-553
Lime-treated water of unbleached kraft pulp wash wastewater (lignin concentration 1226ppm, COD 2544ppm) and pretreated water of bleached kraft pulp caustic soda extract wastewater (lignin concentration 33120 ppm) treated by activated sludge, followed by lime were offered the pilot plant tests for adsorption on granular activated carbon and the possibility of renovation of these treated waters was investigated.
Adsorption isotherms of several wastewater samples including treated waters were simultaneously determined and the relationship between adsorption isotherm and the carbon usage obtained from plant tests was developed.
At a superficial velocity of 1.7m/hr and contact time of 140 min., the carbon usages of lime-treated water were 3, 530l/kg·air-dried carbon on the basis of lignin breakthrough curve and 3, 090l/kg·air-dried carbon on the basis of COD breakthrough curve.In order to examine the effect of lime treatment for wash wastewater, dilute water of wash wastewater equal to lignin concentration of lime-treated water was prepared and offered the pilot plant test in the same condition as lime-treated water.The carbon usages on the basis of lignin and COD were 310 and 3, 670l/kg·air-dried carbon respectively.
From these results, it is apparent that the adsorption of lignin on activated carbon by lime treatment increases but the adsorption of COD hardly increases.These results are consistent with the results obtained from adsorption isotherms of lime-treated water and dilute water.
Similarly, the carbon usage of pretreated water of caustic soda extract wastewater was 130l/kg·air-dried carbon on the basis of lignin breakthrough curve. This small carbon usage mainly may be ascribed to high lignin concentration of influent because at the same initial lignin concentration adsorption capacity of pretreated water of caustic soda extract wastewater is rather larger than lime-treated water of wash wastewater.
