Removal of Heavy Metals Using Aluminum Salts for Phosphorus Removal

摘要

The use of aluminum salts to remove phosphorus is common practice. It has been shown that aluminum salts are also capable of removing heavy metals, but the dosages were much greater than normally applied for phosphorus removal. This study investigates the removal of heavy metals in treatment plants which utilize aluminum salts for phosphorus removal. By choosing POTW's which practice phosphorus removal during the summer only and sampling before and after the discontinuation of aluminum salt addition, the effect of aluminum salt precipitation on heavy metal removal was determined. The results show that copper, chromium, and to some extent, lead removal was enhanced by aluminum salt addition. For chromium, it appears that sodium aluminate addition improved removal but alum addition has no effect. The results confirm that phosphorus removal is enhanced greatly by the precipitant addition. Of the other metals evaluated, aluminum salt addition appeared to have no significant effect on cadmium and antimony removal, nor did it affect TOC removal.