Solar-catalytic treatment of an industrial wastewater

We have investigated the solar-catalytic degradation of organic compounds present in a biologically pretreated effluent of the Werk Wolfsburg of the Volkswagen AG in a pilot plant with twelve double-skin sheet photoreactors (DSSR) under solar irradiation. Ti tanium dioxide was used as the photocatalyst. In typical experimental runs more than 50% of the organic pollutants initially present in the mixed water inside the pilot plant were degraded within eight to eleven hours of solar illumination. The following kinetic expression was used to analyse the solar experiments c = c(0) X exp(-k(1) X k X integral I-UV dt) with c,: initial concentration of the pollutants (determined as TOC or GOD), k(1) = A(R)/V,: ratio between the illuminated (light-harvesting) reactor area and the volume of the suspension in the system under consideration, k: kinetic parameter, and SI,, dt: total UV energy reaching the light-harvesting area of the solar reactor. While the values calculated for k, vary between 16.0 and 27.3 m(2) m(-3). those calculated for k from the TOC reduction k(roc)) and from the COD reduction (k(COD)) vary between 0.034 and 0.295 m(3) kW(-1) h(-1), and 0.017 and 0.505 mi kW(-1) h(-1), respectively.