Grantee Research Project Results
Multidisciplinary Approach to Understanding the Fate and Transport of Natural and Engineered Nanoparticles in Wastewater Treatment SystemsEPA Grant Number: FP917495
Title: Multidisciplinary Approach to Understanding the Fate and Transport of Natural and Engineered Nanoparticles in Wastewater Treatment Systems
Investigators: Ray, Jessica Renee
Institution: Washington University
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: August 28, 2012 through August 27, 2015
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2012)
Research Category: Academic Fellowships , Fellowship - Environmental Engineering
There have been reports of an increasing number of nanoparticles in wastewater streams from industrial, natural or engineered sources. Wastewater treatment plants often use biofilm, a naturally occurring microbial film, for removing organic materials in influent streams; however, it still is unclear how nanoparticles affect such biofilm properties as its microbial activity, and its physical and chemical structure. This research project will seek to gain a holistic understanding of the role of nanoparticle structure and stability on the fate and transport of contaminants in the presence of biofilm, by investigating interactions of model natural and engineered nanoparticles, contaminants and natural organic matter with biofilm. The results will help to predict and control adverse consequences of the rising number of nanoparticles in wastewater streams.Approach:
The first phase of this research will involve synthesizing and characterizing the nanoparticles. Hematite iron oxide and cerium oxide nanoparticles were chosen to model natural and engineered nanoparticles potentially found in wastewater streams. Bare and organic-coated nanoparticles will be used in the project, as often nanoparticles exist in nature accompanied by a surface coating for stabilization. The second phase will investigate the interactions of the nanoparticles with organic and inorganic contaminants in the presence of different substrates (including biofilm) using a diverse array of instrumentation for in situ analysis. The final phase involves creating a porous media channel to elucidate the transport of the nanoparticles in simulated wastewater streams and other aqueous systems.Expected Results:
A better understanding of the behavior of nanoparticles and contaminants in wastewater treatment systems will enable the design of more efficient and effective biofilm reactors that are more equipped to respond to the increasing number of nanoparticles in influent streams. The diverse and advanced nanoparticle methods used will help to determine whether nanoparticles and/or biofilm transformations during and after reaction will introduce more contaminants into effluent water, remove nanoparticles from the system, or result in an overall enhanced removal of contaminants. The results from this research project and research techniques can be used to design a reactive transport model that accurately accounts for nanoparticle-contaminant-biofilm interactions, including the degree of transverse and longitudinal mixing and aggregation. The proposed reaction system will be extremely advantageous in perceiving the physical and chemical evolution of environmental and engineered nanoparticles and biofilm in wastewater treatment systems.
Potential to Further Environmental/Human Health Protection
It is well documented that nanoparticles often exhibit different structures and reactivities compared with their bulk counterparts, which often includes a higher degree of toxicity. Nanoparticles are being generated at higher rates either as byproducts of industrial processes, as intentionally manufactured products for specific purposes, or as precipitates from natural aqueous processes. This has been shown to result in increased nanoparticle amounts in water and wastewater treatment systems. If biofilm is found to be ineffective in sequestering organic contaminants because of interactions with the increasing number of nanoparticles, the toxicity of the effluent stream could be significantly enhanced, posing a threat to human health and the environment. The findings from this research project will better inform the public about the degree of uptake and removal of nanoparticles and contaminants by wastewater treatment systems.Supplemental Keywords:
nanoparticles, wastewater, biofilms