For the prediction of the elimination efficiency of micropollutants from wastewater by ozone, the ozone rate constants of the micropollutants and the kinetics of the reaction of ozone with wastewater must be known. The latter is multiphasic with k = 0.071 (mg DOC)(-1) s(-1) for the first mg/L ozone (at a DOC of 7.2 mg/L) followed by 0.011 (mg DOC)(-1) s(-1) the next 5 mg/L ozone and the k = 0.0019 (mg DOC)(-1) s(-1) for subsequent 4 mg/L ozone as determined by stopped-flow and batch-quench methods. An analysis of gel permeation and UV absorption data indicates that the wastewater DOC is largely polymeric, and at 12 mg/L the concentration of its subunits must be near 100 microM with epsilon(254 nm) approximately 3000 M(-1) cm(-1). The *OH radical yield as determined by the tertiary butanol assay is approximately 13%. From its dose dependence, it follows that new *OH-generating sites are formed during ozonation. The *OH scavenging capacity of the wastewater DOC has been determined at 3 x 10(4) (mg DOC)(-1) s(-1). The contribution of bicarbonate to the OH scavenging capacity is small in comparison, approximately 10% of DOC. Simulations indicate that at 5 mg/L ozone only the most reactive (k > 3 x 10(30 M(-1) s(-1)) micropollutants are fully eliminated but at 10 mg/L ozone the slow ozone decay starts to contribute and even the much less reactive ones (k = 300 M(-1) s(-1)) are oxidized (25% remaining).

The adsorption on powdered activated carbon (PAC) of ecotoxic or potentially ecotoxic micropollutants (ten pharmaceuticals, four X-ray contrast media, and eight industrial chemicals) present in a biologically treated municipal wastewater is studied. All but the X-ray contrast media are eliminated with high efficiency at an economically feasible PAC dosage of 10 mg/L. Based on the experimental data, the competition between the background organic matter and the micropollutant for the active sites of the adsorbent is modeled with the help of the adsorption and tracer analysis supported by the Ideal Adsorption Solution Theory. With granulated activated carbon, adsorption isotherms are determined by spiking. Based on these experimental data and modeled parameters, a lay-out of fixed-bed adsorbers may be simulated.

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