| "Nonylphenol (NP) is known to be byproduct of nonylphenol ethoxylates (NPEOs) which are used as detergent for industrial use. It is important that not only NP but also NPEOs and their related substances are analyzed when behavior of NP in wastewater treatment process is surveyed. NPEOs are biodegraded to shorter ethoxylate (EO) chain NPEOs or nonylphenol carboxylates (NPECs) under aerobic condition, and then biodegraded to NP under anaerobic condition. NP is one of the suspected EDs. Moreover, shorter EO chain NPEO has higher toxicity than longer EO chain NPEO. We conducted field survey of NP and its related substances in 20 wastewater treatment plants (WWTPs). The concentrations (median) of NP and its related substances in WWTPs in fluent ranged from 0.2 nmol/l to as high as >20 nmol/l, showing NP concentration same level as those previously reported. The reduction of the long EO chain NPEOs in WWTPs was almost complete, while removal efficiency for short EO chain NPEOs was less significant than long EO chain NPEO, suggesting that the degradation rate of short EO chain NPEOs were smaller than those of long EO chain NPEO in the wastewater treatment processes." |
