INTEGRATING NANOSCALE ZERO-VALENT IRON AND TITANIUM DIOXIDE FOR NUTRIENT REMOVAL IN STORMWATER SYSTEMS

Nutrients, such as nitrate, nitrite, and phosphorus, are common contaminants in many aquatic systems in the United States. Ammonia and nitrate are both regulated by the drinking water standards in the US primarily because excess levels of nitrate might cause methemoglobinemia. Phosphorus might become sources of the eutrophication problems associated with toxic algae in the freshwater bodies. Toxic algal blooms can cause severe acute and chronic public health problems. Chemical reduction of nitrate by using zero-valent iron started as early as 1964, and considerable research reports relating to this technology to nanomaterial were extensively reported in 1990s making the use of nanoscale zero-valent iron (NZVI) particles for nitrate removal become one of the most popular technologies in this field. The purpose of the present study was to examine the potential of integrating green sorption media, such as sawdust, limestone, tire crumb, and sand/silt, with two types of nanoparticles, including NZVI and Titanium Dioxide (TiO₂), for nitrate removal in an engineering process. The study consists of running packed bed column tests followed by the addition of NZVI and TiO₂ to improve nitrate and phosphorus removal efficiency. Preliminary results in this paper show that the potential and advanced study may support the creation of design criteria of stormwater and groundwater treatment systems for water reuse in the future.