Research

2005-present

 Elimination and Microbial Impact of Selected Pharmaceutically Active Compounds(PhACs) in Wastewater Treatment Plants(WWTPs)

PI: Dr. Gunsch

Many PhACs can undergo hydrolysis in the environment and become active again or simply accumulate  leading to adverse human and environmental health effects.  The extent and magnitude of the risks posed by the presence of PhACs is not yet known due to a lack of research data.  However, there are many concerns that PhACs may threaten the physiological and reproductive processes of micro and macro aquatic organisms and that they may have adverse human health effects.  In addition, there is also the potential that disease causing microbes may develop resistance to PhACs, ultimately leading to an increase risk of human diseases.  To date, in our research with PhACs, we have focused at studying the microbial inhibition resulting from their presence in WWTPs.

2007-present

Pilot Scale Investigation of Integrated Fixed Film Activated Sludge (IFAS): The South Durham IFAS Pilot Research Facility

PI: Dr. Schuler, Dr. Gunsch
 

IFAS is a promising technology with great potential to improve the performance of biological wastewater treatment plants by adding media to conventional, suspended growth (activated sludge) systems to provide surfaces for microbial attachment. This attached microbial growth provides increased rates of waste degradation and removal, and is thought to be particularly well suited for increasing rates of ammonia conversion to nitrate (nitrification). Because of its simplicity and low space requirements, IFAS may be ideal for increasing the capacity of existing systems without building additional reactors. We have built a pilot wastewater treatment system to investigate fundamental and practical aspects of IFAS process. We are now focusing on identification and characterization of biofilm microorganisms using molecular methods.              

2007

Biocidal Effect of Fullerene Nanoparticles in Aqueous solution and Attached to Microfiltration Membranes

PI: Dr. Wiesner, Dr. Gunsch
 

Studies have reported the potentially harmful environmental impacts of fullerene (C₆₀). However, some beneficial uses of fullerene may be discovered through an interesting new avenue of research to incorporate them into microfiltration (MF) membranes widely used for water and wastewater treatment. It is expected that this paper can provide deep insights into the functions of colloidal aggregated forms of fullerene (nC₆₀) in the bacterial affinity for attachment to MF membranes and potential toxicity to bacteria. As a result, it was found that surface charge and hydrophobicity of the MF membranes played important roles in attachment of Escherichia coli K12 to the membranes and that the amount of nC₆₀ was a key factor for inhibition of bacterial activity. This suggests that nC₆₀ within or upon an MF membrane could mitigate membrane biofouling by decreasing attachment of biomass. This should prolong filtration time by reducing the number of times that the membrane must be completely cleaned. It was also found that nC₆₀ in aqueous solution first inhibits the metabolic activity of bacteria causing their death and decrease of their total number.            

2007

Inhibitory Effects of Selected Brominated Flame Retardant on Microorganisms Originated from Wastewater Treatment Plants

PI: Dr. Stapleton, Dr. Gunsch
 

Polybrominated diethyl ether (PBDEs) brominated flame retardants are extremely stable and tend to accumulate in wastewater treatment biosolids. It may ultimately leadi to an increase risk of wildlife and human. We were looking for the toxicological response initiated by PBDEs in microorganisms from WWTPs.            

2006-2007

Antisense DNA as a novel gene silencing method

PI: Dr. Gunsch
 

We are developing tools to utilize antisense DNA for pathogen propagation.  Pathogens could be inactivated by silencing essential metabolic functions which would eventually lead to the death of these microorganisms without the use of toxic chemicals.  This approach to removing pathogens would be appealing because no toxic by-products would remain.            

2003-2005

Organic Matter and Nitrogen Removal in Aeration Membrane Bioreactors (MBRs).

PI: Dr. Huang        

1.      Wang, S., Holzem, R.M., and Gunsch, C.K., “Effects of Pharmaceutically Active Compounds on a Mixed Microbial Community Originating from a Municipal Wastewater Treatment Plant.” Environ. Sci. Technol. 2008; 42(4): 1091-1095.

2.      Chae, S.-R., Wang, S., Hendren, Z., Wiesner, M. and Gunsch, C.K., “Bactericidal Effects of Fullerene C60 Nanoparticles on Microfiltration Membrane Surfaces and in Aqueous Suspension.” Environ. Sci. Technol. 2008 revised and resubmit.

3.      Wang, S., C. Wang, P. Liang, and X. Huang, “Study on Carbon and Nitrogen Removal by Membrane Aeration Bioreactor.” China Water and Wastewater. 2007. 23(9):40-43 (Chinese).

4.      Wang, S., C. Wang, and X. Huang, “Membrane aerated bioreactor for wastewater treatment.” Techniques and Equipment for Environmental Pollution Control. 2006. 7(6): 131-137. (Chinese).

1.    Wang, S. and C.K. Gunsch, "Effects of Pharmaceutically Active Compounds on a Mixed Microbial Community under Different Organic Loadings". Accepted for presentation at the 108th General Meeting of the American Society for Microbiology, Boston, Massachusetts (June 1-5, 2008).

2.    Wang, S. and C.K. Gunsch, "Antisense DNA: A Novel Gene Silencing Method".  Accepted for presentation at the Association of Environmental Engineering and Science Professors Meeting, Blacksburg, Virginia (July 28-August 1, 2007).

3.    Wang, S. and C.K. Gunsch, "Impact of Antisense Target DNA Length on Gene Silencing in Pseudomonas putida F1".  Accepted for presentation at the 107th General Meeting of the American Society for Microbiology, Toronto, Canada (May 21-26, 2007).

4.    Wang, S. and C.K. Gunsch, "Inhibitory Effect of Four Pharmaceutical Compounds on Microbial Growth".  Accepted for presentation at the 106th General Meeting of the American Society for Microbiology, Orlando, Florida (May 21-25, 2006).