Solar photocatalytic decontamination of wastewater from the rinsing of pesticide containers

One of the sources of high-pesticide-content polluted waters is the rinsing of used pesticide spray containers and their disposal. The main characteri stics of this wastewater are its extreme toxicity, low volume and well-defi ned location. Suitable treatment is therefore required to prevent this poll ution, which is easier than cleaning up the environment afterwards. In this paper, a pre-industrial solar TiO2-photocatalytic treatment is used for th is purpose. Commercial pesticides (Lufenuron and Propamocarb) are used to d emonstrate the practical application of the treatment. The photocatalytic p ilot plant used for these tests has 6 CPC modules (collector surface 8.9 m( 2), photoreactor volume 108 L, total plant volume 247 L) connected in serie s and mounted on a platform inclined 37 degrees. The results are compared w ith phenol degradation under the same experimental conditions, and relative photonic efficiency (xi(r)) is calculated to facilitate comparison with ot her experimental devices. Total Organic Carbon (TOC) analysis is employed t o confirm the mineralization of the contaminants, Relative photonic efficie ncy related to TOC is also introduced (xi(r,TOC)). The pesticides were comp letely photodegraded, but mineralization is slow with only illuminated TiO2 . The use of an additional oxidant (peroxydisulphate) enhances the degradat ion rate by 5 (propamocarb) and 9 (lufenuron), compared to TiO2 alone.