| Title |
The Improvement of Thickening and Dewaterability of Alum Sludge by Pretreatment Processes |
| Authors |
권동민(Dong Min Kwon), 이병헌(Byung Hun Lee), 박은정(Eun Jung Park) |
| Abstract |
In the water treatment plant, chemical treatment process is increasingly used for reducing such impurities as suspended solids and organic materials. Many water treatment plants has been adapted chemical treatment process using alum as a primary coagulant. The use of alum is producing a waste commonly called alum sludge. Alum sludge is a bulky gelatinous substance composed of aluminium hydroxides, inorganic particles such as clay or sand, colloids, microorganisms, etc. It has relatively low solid content that is difficult to thicken and dewater. This study attempted to investigate the effect of thickening and dewatering of alum sludge in Duk-san water treatment plant through pretreatment using sulfuric acid, lime and polyacrylamide. The main results obtained in this study are summarized as follows: In case of alum sludge pretreated by sulfuric acid, the effect of thickening increased with proportion to concentration of aluminium extracted, while the dewaterability was mainly affected by the extraction ratio of aluminium and TOC concentration. Alum sludge pretreated by lime enhanced both thickening and dewaterability. It appeared that extracted aluminium and organics were adsorbed to non-dissolved lime and removed by co-precipitation. The thickening velocity and dewaterability increased by dosing polyacrylamide but the final effect of thickening was not appeared. |