Removal of toxic substances in anaerobically digested sewage sludge using advanced oxidation process

pH2の条件下での過酸化水素(H2O2)とFeイオンを用いた促進酸化法により，下水消化汚泥中のノニルフェノール(NP)と重金属類の同時除去における試薬添加量の影響について検討した. H2O2とFe(II)イオンまたはH2O2とFe(III)イオンを添加した場合での，NPの分解に対する最適な試薬添加量は，H2O2とFe(II)イオンは5g/lと0.33g/ l ，H2O2とFe(II)イオンでは2g/lと0.82g/lとなり，除去率はそれぞれ65%と48%となった.これらの条件において汚泥中のリンを損失せずに重金属を効率的に溶出除去できた.さらに，ベンゼン環の炭素を放射性同位体炭素(14C)で標識したNPを用いて，NPの無機化とベンゼン環の分解の程度について検討を行った.その結果，NPは分解されるが，ベンゼン環の分解による無機化は起こらないことが分かった.Simultaneous removal of nonylphenol (NP) and heavy metals from anaerobically digested sewage sludge using H2O2 and Fe ion at pH 2 was investigated at different amounts of the reagents added. When both H2O2 and Fe (II) ion or both H2O2 and Fe (Ill) ion were added, the optimum amounts were respectively 5 g/1 H2O2 and 0. 33 g/1 Fe(II) ion or 2 g/1 H2O2 and 0. 82 g/1 Fe (Ⅲ) ion for NP degradation, which resulted in the degradation efficiencies of 65% and 48%, respectively. Under these optimum conditions, heavy metals were effectively removed from the sludge solid, whereas phosphorus was retained. In addition, the mineralization of the benzene ring forming NP was investigated utilizing NP labeled with radiocarbon. It was found that no mineralization by degradation of the benzene ring in NP occurred in the Fenton process