Abstract
Our laboratory wastewater namely medium-waste, Hg-trap-waste and ligand-waste were treated by the use of sedimentation method, Fe-powder column method and anion exchange resin method. Most of mercury in the medium-waste was adsorbed on suspended solid (SS) composed of Bacteria or Chlorella and a part of mercury was dissolved. The Hg-trap-waste contained no ligands and the ligand-waste contained Br-, I- and EDTA which complex Hg2+ strongly. By the addition of 0.05% of ferric chloride to the medium-waste, the mercury adsorbing on SS was efficiently precipitated but the dissolved mercury was not removed. Dissolved mercury in the Hg-trap-waste and medium-waste was well recovered by the Fe-powder column method. By the using of 5g of Fe powder, over 96% of dissolved mercury in 20l of these wastes was removed. When the anion exchange resin method was applied to the Hg-trap-waste and the ligand-waste, mercury in 100l of the Hg-trap-waste or in 50l of the ligand-waste was well removed with 10 ml of resin.
From above results, it is concluded that the Fe-powder column method is useful to remove dissolved mercury in laboratory wastewater containing ligands and the anion exchange resin method is effective as the secondary treatment.
