| 摘要 |
<p>By adding an iron salt, the sedimentation property, the concentration property, and the filtration property of sludge in an activated-sludge mixed liquor in a biological treatment tank are effectively improved and treated water of high quality is efficiently provided. When an iron salt such as ferrous chloride, ferric chloride, or polyferric sulfate is added to organic wastewater and the organic wastewater is biologically treated, the iron salt is added to the organic wastewater and mixing is conducted; and the water mixture is mixed with activated sludge and biologically treated. By mixing organic wastewater and an iron salt at a pH close to an optimum pH for ferric hydroxide in advance, the turbidity of the treated water due to the formation of iron oxide or ferrous carbonate is suppressed.</p> |
