Abstract
The removal of nonylphenol (NP) and heavy metals in anaerobically digested sewage sludge was investigated using potassium ferrate as an oxidizer. NP in the aqueous sample was removed with ferrate ion under the weakly acidic conditions more effectively than strongly acidic conditions. The amount of iron required to remove NP was much lower compared to the Fenton process using ferrous ion and hydrogen peroxide. In the sludge sample, almost same amount of iron as the Fenton process was required for NP removal even under the neutral pH condition. The greatest NP removal was achieved at an initial pH of 3.5. As, Cd, Cu and Zn in the sludge were also removed by acidifying the sludge even after the addition of potassium ferrate. These findings suggest that NP and heavy metals could be removed from the sludge by the two-step process composed of oxidation with K2FeO4 and acidification.
