Effect of Nano ZnO Photocatalyst on Some Water Parameters of Neckar River (Germany) and Animal Farm Wastewater

This study evaluated the effectiveness of a nano-ZnO photocatalyst under UV light for the rapid treatment of two distinct water sources: surface water from the Neckar River and wastewater from a pig farm, with a short exposure time of 10 minutes. The results showed that the nano-ZnO/UV system achieved a significant reduction in Total Organic Carbon (TOC) by 26% in river water, whereas UV radiation alone was ineffective. Treatment efficiency was considerably lower (8% TOC removal) in the complex pig farm wastewater, underscoring the influence of the water matrix. While the process created a strong oxidative environment, indicated by a significant increase in redox potential, it did not significantly alter inorganic nutrient levels (nitrate, nitrite, phosphate) or general physicochemical parameters (electrical conductivity (EC) and total dissolved solids (TDS)). A notable finding was the significant leaching of zinc ions, pointing to a key challenge for practical application. The research concludes that while effective for organic matter degradation in simpler waters, nano-ZnO photocatalysis at short retention times is less suitable for complex wastewaters and requires strategies to improve catalyst stability.