Copper Mediated Selective Removal of Nit

Current efforts to upgrade wastewater treatment plants focus on biological nitrogen and phosphorus removal, yet nitrogen removal is often hindered by the presence of nitrification inhibitors in industrial effluents. This study investigates the role of copper in counteracting the effects of these inhibitors. Using batch inhibition tests and bench-scale semi-continuous activated sludge reactors, we demonstrate that the addition of Cu(II) significantly reduces nitrification inhibition in four industrial wastewaters, with Cu(I) or particulate Cu(0) showing even greater efficacy. In contrast, conventional additives like activated carbon or zeolite were ineffective. To avoid contamination of waste-activated sludge associated with direct Cu(II) addition, we explored pretreatment processes utilizing surface-immobilized copper forms, such as particulate Cu(0) and Cu(II)-loaded chelating resins. These immobilized forms proved more effective at detoxifying industrial effluents and model inhibitor solutions compared to soluble Cu(II). X-ray photoelectron spectroscopy analysis indicates a surface complexation mechanism at play. Additionally, the immobilized copper phases can be reused in a pretreatment contact unit, providing a sustainable approach to managing nitrification inhibition in wastewater treatment systems.