The high degree treatment of unbleached kraft pulp washing wastewater has been studied for renovation of pulp wastewater.
The sequential treatment of unbleached kraft pulp washing wastewater by pilot plant was carried out in the period of 45 days for establishment of renovation technique. This process consisted of activated sludge, lime and activated carbon adsorption treatments.
The activated carbon adsorption treatment was attempted for the water pretreated by activated sludge and lime. The fixed-bed activated carbon adsorption column system consisted of six columns. Each column was 2 m in length and 15 cm in diameter and each column was filled with the granular activated carbon of 830 mesh. The flow rate was 601/hr.
The results of pilot plant test are as follows :
Raw wastewater quality was COD
ca. 400 ppm, lignin
ca. 280 ppm and color
ca. 2400 (platinum units). Combination of activated sludge treatment and lime treatment resulted in
ca. 90% removal of COD,
ca. 85% removal of lignin and
ca. 90% removal of color.
The activated carbon adsorption treatment resulted in colorless, extremely low COD water suitable for reuse and the adsorptive efficiency of each activated carbon adsorption column was estimated.
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