EFFECT OF TEMPERATURE, PH AND VEGETATION ON THE REMOVAL OF ZINC FROM MINE WATER IN AEROBIC WETLAND MESOCOSM

抄録

 This study investgeted the effect of temperature, pH and vegetation on removal efficiency of zinc from mine water in aerobic constracted wetland mesocosm. During two month operation, the removal efficiency of zinc was sharply decreased from 92% to 52% in unvegetated wetland mesocosm and from 95% to 39% in vegetated, respectively. However, by maintaining neutral pH condition using limestone, pH in the unvegetated wetland gradually increased which followed by high zinc removal, revealing a good correlation of zinc removal with pH. It was obvious that zinc removal in vegetated wetland was lower than that in unvegetated. Despite presence of limestone, the removal of zinc decreased when temperature decreased. Adsorption experiments in batch and continuous system proved the effect of temparure and pH on zinc removal observed in aerobic wetland mesocosm. The result of speciation of zinc by sequential extraction suggested that zinc removed in aerobic wetland mesocosm was mainly consisted of exchangeable form. It was considered that because oxygen supplied from roots caused pH decline, the fraction of exchangeable form in vegetated wetland as well as amont of zinc removed was lowed compared with unvegetated wetland.