State Water Resources Research Institute Program

Project ID: 2009MA178B
Title: Impact of Nanoparticles on the Activated Sludge Process: Effects on Microbial Community Structure and Function
Project Type: Research
Start Date: 4/ 1/2009
End Date: 3/31/2010
Congressional District: 5th
Focus Categories: Toxic Substances, Wastewater
Keywords: Activated sludge, carbon nanotubes, nanomaterials, emerging contaminants, molecular microbial ecology, microbial community analysis, ARISA
Principal Investigator: Rooney-Varga, Juliette ; Goyal, Deepankar
Federal Funds: $ 5,000
Non-Federal Matching Funds: $ 10,400
Abstract: Nanotechnology offers a vast array of promising new materials with unique physical, chemical, and biological properties. In particular, carbon nanotubes (CNTs) have far-reaching potential applications as components of personal care products, pharmaceuticals, electronic devices, energy storage devices, stains and coatings, and new environmental clean-up technologies. While Massachusetts is poised to be a leader in nanotechnology, relatively little is known about the potential health and environmental risks of nanomaterials. As nanomanufacturing and use of nanomaterials become widespread, CNTs and other nanomaterials will inevitably be released into wastewater streams and enter treatment plants. All publicly owned wastewater treatment facilities rely on the 'activated sludge process,' in which controlled microbial degradation of waste materials removes chemical and biological contaminants. Several pure culture studies have indicated that CNTs can exhibit strong microbial toxicity, raising the possibility that they will disrupt microbial communities responsible for biological wastewater treatment and thereby cause the release of untreated contaminants into the environment. However, to date, the impact of CNTs on activated sludge microbial communities is not known.

The graduate research project proposed here will use state-of-the-art molecular biology approaches to analyze the impact of CNTs on microbial communities in activated sludge. Specifically, the proposed research will:

1. determine which phylogenetic groups of activated sludge bacteria are adversely impacted or selectively enriched due to MWCNT exposure, and

2. develop and apply molecular approaches to effectively track the microbial eukaryotic community in activated sludge exposed to MWCNTs.

This research will rely on a multidisciplinary approach that combines environmental engineering and state-of-the-art molecular microbial ecology techniques. Through our collaboration with Dr. X.J. Zhang and coworkers, we have access to samples from activated sludge batch reactors exposed to various levels of CNTs. Automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphism (T-RFLP) will be used to generate genetic 'fingerprints' of activated sludge bacteria and microbial eukaryotes, respectively, from experimental CNT-exposed and control reactors. Sequence analysis of the SSU rRNA gene will be used to determine the identity of specific microorganisms impacted by CNT exposure. This approach will enable us to determine how specific microbial groups are impacted.

The proposed research will provide an assessment of how an emerging contaminant, CNTs, affects the activated sludge process and which specific microbial groups/functions may be vulnerable. Such insight is needed to ensure the sustainable development of nanotechnology, before nanomaterials such as CNTs are released into our environment in large quantities.

Progress/Completion Report, 2009, PDF

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