Evaluation of Impact of Nanoparticle Pollutants on Water Reclamation
Year Released: 2013
Funding Partner: Bureau of Reclamation, South Bay Water Recycling (CA)
Total Investment: $127,466.57 (Cash: $94,992, In-Kind: $32,474.57)
Principal Investigators: Rajagopalan Ganesh, Ph.D., Kennedy/Jenks Consultants, and Diego Rosso, Ph.D., University of California Irvine
In the very near future, the water reclamation industry will have to address an entirely new family of pollutants, manufactured nanomaterials. Manufactured nanomaterials are extremely small in size (1–100 nm in at least one dimension), are potentially highly reactive, and are often manipulated at the molecular level to generate “new” types of compounds. In recent years, more than 1,000 everyday products containing nanomaterials have been introduced into the market.
Goals and Objectives
The project obtains preliminary information on the fate and impact of manufactured nanomaterials in three key water reclamation unit processes (biological treatment, media filtration, and disinfection).
Bench-scale studies were performed to evaluate the following:
- Do nanomaterials behave differently than conventional (dissolved/ionic) constituents in water reclamation processes?
- What is the impact of size of nanomaterials on water reclamation?
- Do different nanomaterials behave similarly in these treatment processes?
This report is organized into ten chapters. Chapter 1 provides a background of the issue and study objectives. Chapter 2 presents a brief summary of current state of knowledge. Chapter 3 discusses the approach and methods used in this study. Chapters 4 through 9 present and discuss the results of this study. Chapter 4 presents data on characterization of various nanomaterials used. Chapter 5 presents results from studies on removal of nanomaterials. Chapter 6 provides data from microbial growth and respiration studies. Chapter 7 presents data on gross operational parameters in bioreactors in the presence of nanomaterials. Chapters 8 and 9 present data from media filtration and chlorine demand evaluation studies. Finally, Chapter 10 provides a summary of the results and recommendations for the next steps.
Findings and Conclusions
The data indicated that, the metaloxide nanomaterials used in this study were removed more effectively than ionic salts from the wastewater. SEM analyses of removed solids showed distinctly different structural characteristics between nanomaterials and their ionic salts, indicating that mechanisms of their removal are different in the wastewater. Toxicity study data indicated that inhibition to respiration and growth of coliform and ammonia oxidizing bacteria were lower in the presence of nanomaterials than their ionic counterparts. This is likely due to higher removal of nanomaterials than ionic salts. Column tests performed to evaluate the transport of nanomaterials in media filter indicated that nanomaterials tend to aggregate and deposit more than ionic salts. Ionic zinc breakthrough occurred early and the peaks were higher than nanomaterials. The differences in the breakthrough patterns were more pronounced for larger media (0.45 mm) than for smaller media (0.175 mm). Finally, evaluation of chlorine demand in ionic zinc and nano zinc oxides indicated no significant differences.