| 摘要 |
<p>A method to detoxify municipal sewage sludge containing heavy metals comprises the steps of mixing in a vessel (12) sewage sludge, at least one catalytic oxidant (24) such as a ferric salt, at least one regenerative oxidant through a pump (36) and an acid (16) to form a reacting slurry having a solids fraction and a liquid fraction and, after a suitable retention time, separating the solids fraction from the liquid fraction. The reacting slurry is maintained during its retention time at pH range between approximately 1.0 to 2.0 and at an oxidation reduction potential of, at least, +400 millivolts. The heavy metals originally absorbed into the solids fraction of the sewage sludge solubilize into the liquid fraction of the reacting slurry. Thereafter, the reacting slurry is discharged into a conventional solids/liquid separating device (42) so that the metal-laden liquid fraction becomes separated from the solids fraction which is now substantially barren of heavy metals. The solids fraction is neutralized to a pH prescribed by EPA regulations so that it can be safely applied to agricultural land as a detoxified fertilizer and soil conditioner.</p> |
