| 摘要 |
PURPOSE:To provide safe discharge water and effectively utilize the separated matter as a heat source by separating oil and solid components in waste water, evaporation-treating it with air and steam to remove scum, and efficiently separating and removing heavy metals, cyanides, and the like. CONSTITUTION:After oil and solid components in thermal cracking waste water of city solid waste are removed, it is contacted with counterflow of air and steam and the evaporated components are condensed and scum is removed. After the evaporation treatment water is adjusted in pH to about 10, a high polymeric flocculant and a ferrate are added for flocculation and separation of heavy metals and reducing substances. The separated water is adjusted in pH to about 10-12, added with an axidant, subjected to a primary oxidation at an oxidation potential of at least 300 mV, and subjected to a secondary oxidation at pH of about 8-9 and at an oxidation potential at least 650 mV for dissociation and removal of cyanides. The water is then added with a high polymeric flocculant for flocculation and removal of heavy metals and reducing substances, neutralized, subjected to sand filtration and activated carbon treatment, and discharged. The sludge obtained by enrichment and dehydration of the matter separated on each step is effectively utilized as a heat source for a heating medium for thermal cracking. |
