Behaviour of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-nonylphenol ethoxylates (4-NP1EO, 4-NP2EO) in oxidative water treatment processes

Abstract

Endocrine disrupting chemicals (EDCs) such as natural and synthetic hormones or industrial chemicals can adversely affect the endocrine system at very low concentrations. As such substances can be present in raw water used for drinking-water production, they potentially pose a health risk to humans. In this study laboratory tests were performed to determine removal efficiencies of selected oxidative drinking water treatment processes, namely ozonation (1.4 mg/l O3) and chlorination, using sodium hypochlorite (0.5 mg/l NaClO) and chlorine dioxide (0.4-0.6 mg/l ClO2) under conditions applied in technical plants. 500-300,000 ng/l of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-nonylphenol-n-ethoxylates (NPnEO) were selected for investigations and measured by HPLC/FLD and HPLC/MS. To investigate possible oxidation by-products, adsorbable organic halogens (AOX) were determined and estrogenic activities were assessed with the help of an estrogen receptor binding assay (YES). Ozonation and chlorination with ClO2 removed both 4-NP and BPA below detection limits, corresponding with AOX and estrogenic activity. Concerning NPnEO ozonation removed NP1EO and NP2EO up to 28% and 30%, respectively, whereas ClO2 showed high removal efficiencies, eliminating >94% and 92%, respectively. NaCIO removed 4-NP and BPA below detection limits, but estrogenic activities increased and AOX could be measured. NP1EO and NP2EO were only marginally reduced corresponding to the slight decrease of estrogenic potential.

Synthetic endocrine disruptors in the environment and water remediation by advanced oxidation processes

“…Lenz et al (2004) found that in a solution containing 1.4 mg l À1 ozone, the concentration of 4-NP (C 0 ¼ 1-200 mg l À1 ) could be reduced to less than 20 ng l À1 within 5 min and the estrogenic activity to less than 95% of the original. A similar study by Kim et al (2005) showed that despite the rapid breakdown of 4-NP by 1 h ozonation, the concentration of dissolved organic carbon remained constant throughout.…”

“…They found that 99% of BPA was converted with an initial ozone concentration of 30 mM in less than 2 s. However, the level of estrogenicity increased during initial contact, declined after subsequent contact and stabilized after 60 min, signifying that the oxidation byproducts had higher estrogenic activity than BPA and some residual estrogenic response remains after treatment. Behavior of BPA in oxidative water treatment facilities was also studied by Lenz et al (2004), who reported 1.4 mg l À1 as the optimum O 3 concentration for complete BPA destruction and 5 min as the sufficient contact time for removing the endocrine activity without the formation of adsorbable organic halogens.…”

Effect of the injection of pure oxygen into a membrane bioreactor on the elimination of bisphenol A

“…Likewise, further research is needed to determine the effect of oxygen on sorption/ desorption equilibrium. Finally, this procedure has demonstrated to be environmentally friendly because it avoids the application of a tertiary oxidative treatment that usually causes secondary pollution (Lenz et al 2004). Moreover, the economical balance is positive despite the higher cost of pure oxygen because the use of oxygen also reduces sludge production, which means lower operating time and lower electricity consumption.…”

“…In this respect, several studies have focused on the application of tertiary treatments, which usually include an oxidative process. These treatments are usually effective (Lenz et al 2004;Schröder 2006) but they may result in high expenses and secondary pollution, caused by the presence of residual amounts of the oxidants or their byproducts in water.…”

Modeling of nonylphenol degradation by photo-nanocatalytic process via multivariate approach

“…Recently, removal of aqueous NPs by electrochemical [8], ozonation [8][9][10][11][12], photolysis with UV [13], Photocatalysis with UV/TiO 2 and UV/BiVO 4 [12,[14][15][16], and Sonolysis with Fe(II) and Fe(III) [17] has been reported.…”