Interactions of CMP nanoparticles and sewage sludge

The use of nanoparticles (NPs) in semiconductor manufacturing continues to increase despite the growing concern over the potential environmental and health effects. The interaction of NPs and sewage sludge is an integral part of determining the ultimate fate of NPs released to municipal wastewater treatment plants (WWTP) as it will determine whether the bulk of the material is contained in the sludge or released in the effluent stream. Analyzing the affinity of aluminum oxide, cerium oxide, and silicon oxide NPs, which are commonly used in chemical mechanical planarization (CMP) processes, for biosolids used in municipal wastewater treatment plants provides a basis for estimating their removal efficiency. Batch studies were performed and the NPs were shown to partition to the cellular surface. It is expected that significant removal of the cerium oxide NPs will be achieved during conventional biological wastewater treatment.