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(456) Nonylphenolic compounds in urban wastewaters: occurence and fate of nonionic surfactants and their metabolites. Giger, Walter1, Wettstein, Felix1, Hoang Thi, Minh Hang1, 2, 1 2 ABSTRACT- In Switzerland nonionic surfactants of the nonylphenol polyethoxylate type (NPnEO) are not used any-more in laundry detergents and in household surface cleaners. However, estimated 500 tons of NPnEO are applied annually for industrial and institutional purposes. This paper reports on investigations in urban wastewater treatment plants, which receive substantial inputs from different types of industrial wastewaters. Among the industrial processes of interest are (i) manufacturing of industrial solvents, (ii) paper production (including recycling) and (iii) textile finishing. Analytical methods based on liquid chromato-graphy combined with fluorometric detection allowed the quantitative determination of NPnEO surfactants and their lipophilic metabolites nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO). In addition, the carboxylated metabolites nonylphenoxy acetic acid (NP1EC) and nonylphenoxy ethoxy acetic acid ( NP2EC) were determined by GC/MS techniques. This study revealed extraordinary maximum concentrations of 3.9 mg NPnEO per liter in a primary sewage effluent. In secondary effluents NP, NP1EO and NP2EO maximized at 18, 20 and 67 Key words: nonylphenol polyethoxylates, degradation products, sewage treatment plant, aquatic environment |
g/L, respectively. These results are compared to concentrations found in treatment plants without special inputs (Ahel et al. Croatica Chemica Acta, 73 (1) 209-227, 2000 and Water Science Technology, 42 (7/8) 15-22, 2000). It will be discussed whether NPnEO loads in the only mechanically treated wastewater correlate with the levels of metabolites in the biologically treated effluents or whether the operating performance of each plant has a more crucial impact. The relative contributions of the various metabolites NP, NP1EO, NP2EO, NP1EC and NP2EC in the effluents will be discussed. Furthermore, concentrations of NP and NP1EO in digested sewage sludges are considered as possible indicators of high NPnEO inputs.