Comment submitted by Maureen Egan, Industrial Pretreatment Specialist II, Littleton/Englewood Wastewater Treatment Plant

The EPA’s “Nanomaterial Case Study: Comparison of Multiwalled Carbon Nanotube and Decabromodiphenyl Ether Flame-Retardant Coatings Applied to Upholstery Textiles (DRAFT)” does not adequately address the potential impacts to wastewater treatment plants (WWTPs) from the introduction of multiwalled carbon nanotubes (MWCNTs). The study identifies the potential release of MWCNTs to WWTPs during the manufacturing, storage and distribution, use, and reuse/recycling/end-of-life stages (2-29). The study’s executive summary states that laboratory-based studies of MWCNTs established acute antimicrobial activity at low exposure concentrations (xxii). Many WWTPs use biological treatment extensively in their processes. MWCNTs behavior and interaction with WWTP microbiology may be influenced by: size, morphology, surface area, chemical composition; surface chemistry and reactivity; solubility and dispersion; and conductive, magnetic, and optical properties (1-19). It is essentially unknown how MWCNTs will behave in WWTPs or what their potential impacts on biological treatment processes may be. It is strongly recommended that evaluation of potential impacts to WWTPs be incorporated into the EPA’s comprehensive environmental assessment (CEA) framework during the impact assessment stage whenever the potential for the introduction of a contaminant to a WWTP during its life cycle is identified. Submitted by: Maureen Egan, Industrial Pretreatment Specialist II, Littleton/Englewood Wastewater Treatment Plant, 2900 South Platte River Drive, Englewood, CO 80110