Emerging Nanomaterials: Pollution and Urban Water Treatment Challenges Jejal Reddy Bathi, Ph.D., P.E., A.M. ASCE, Civil and Chemical Engineering, University of Tennessee at Chattanooga, TN, Water Pollution Engineering Committee, Water wastewater and stormwater council, Environmental Water Resource Institute Faegheh Moazeni, Ph.D., A.M. ASCE, School of Science Engineering and Technology, Penn State Harrisburg University, PA Venkata. R Gadhamshetty, Ph.D., P.E., BCEE M. ASCE, Civil and Environmental Engineering, South Dakota School of Mines and Technology, SD, Water Pollution Engineering Committee, Water, Wastewater and Stormwater Council, Environmental Water Resource Institute Introduction Several municipalities are challenged by urban non-point source pollution due to difficulties associated with their detection and control. The Total Maximum Daily Load (TMDL) program implemented by the Environmental Protection Agency (EPA) regulates pollutant load to impaired receiving waters. Reduction of the pollutant loads requires prior knowledge of pollutant and watershed characteristics in order to design relevant engineering controls. The physical and chemical characteristics of emerging pollutants such as engineered nanomaterial (ENMs) is often unknown. Thus, it is often difficult to detect and regulate the ENMs and implement passive controls. An overarching goal of this review article is to introduce concepts of ENMs, their occurrence, fate and transport in urban waters. This article on ENMs will serve as a preliminary guidance document to watershed management groups including municipalities, state and federal regulators and engineers. The readers are encouraged to review relevant EPA documents to gain detailed insight on scientific details of ENMs (EPA 2017). ENM in Surface Waters Recent global development of nanotechnology has enabled consumer products with ENMs to be present in almost every sector of human life. The increased reach of the ENMs has also led to increased concern over environmental, health and safety which may result from them. For example, the increased concern is indicated by the increased annual funding for nanomaterial research related EHS in U.S from $35 million in 2005 to $100 million in 2016 (Nano.gov). ENMs have been reported to be present in urban environments, with potential sources including point sources such as wastewater treatment plants and manufacturing industries, urban non-point sources, or indirectly via wet deposition following release from a point source into the atmosphere. Widely used in a range of current consumer products, titanium dioxide nanoparticles (n-TiO2), silver nanoparticles (n-Ag), carbon nanotubes (CNTs), zinc oxide nanoparticles (n-ZnO), and cerium dioxide nanoparticles (n-CeO2) are the compounds most likely to occur in surface waters. The ENMs are difficult to detect and treat in urban runoff as they are present only at trace levels. To the best of our knowledge, there are no published scientific studies that quantified ENMs in urban runoff and the corresponding treatment systems.
www.asce.org/ewri • EWRI Currents • Volume 21, Number 3 • Summer 2019