Environ. Sci. Technol. 2009, 43, 6757–6763
Titanium Nanomaterial Removal and Release from Wastewater Treatment Plants M . A . K I S E R , † P . W E S T E R H O F F , * ,† T. BENN,† Y. WANG,† ´ R E Z - R I V E R A , * ,‡ A N D J. PE K. HRISTOVSKI† Department of Civil, Environmental, and Sustainable Engineering, Arizona State University, Tempe, Arizona 85287-5306, and Science and Technology Department, Universidad Metropolitana (UMET), San Juan, Puerto Rico, 00926
Received April 10, 2009. Revised manuscript received June 10, 2009. Accepted June 11, 2009.
Titanium (Ti) occurs naturally in soils and as highly purified titanium dioxide (TiO2) in many commercial products that have been used for decades. We report for the first time the occurrence, characterization, and removal of nano- and largersized Ti at wastewater treatment plants (WWTPs). At one WWTP studied in detail, raw sewage contained 100 to nearly 3000 µg Ti/L. Ti larger than 0.7 µm accounted for the majority of the Ti in raw sewage, and this fraction was well removed by WWTP processes. Ti concentrations in effluents from this and several other WWTPs ranged from
