| 摘要 |
<p>The invention provides a method for the purification of contaminated water such as leachate from a land fill site. The treatment involves the application to the water of anionic and cationic coagulents at different stages, and between the application of the coagulents precipitation agents are added to precipitate the contaminants which typically are metal ions in solution. The coagulants are polyelectrolytes which in the case of the first added coagulant cause formation of a floc and the addition of the second coagulant causes heavy deposition of contaminants. Separation follows and the separated solids are passed to a sludge thickening tank whilst the separated liquid which is of high pH is stripped of ammonia and other nitrogenous compounds. The pH is subsequently reduced to zero and subsequently the carbon dioxide is removed. The remaining liquid can either be subjected to a bio-oxidation treatment or filtered by reverse osmosis in the latter case to provide clean water which can be returned to a stream or river. The invention also provides a novel form of stripping of ammonia and carbon dioxide and a vessel for use in the same.</p> |
