"Microbes
can biodegrade or transform just about any chemical ...
Figuring out ... environmental conditions is the
challenge."
Virginia Tech Resources
Love,
an assistant professor since 1994 in the Environmental Engineering and
Science (ENES) program, defines the field of environmental biotechnology
as the integration of environmental engineering, microbiology, and molecular
biology. Although wastewater engineering has been her primary focus as
a graduate student and faculty member, her Ph.D. program in environmental
systems engineering at Clemson University had a strong microbiology focus,
Love says.
Her goal of establishing an interdisciplinary approach to wastewater engineering led the National Science Foundation (NSF) to award her a four-year Faculty Early Career Development grant in 1995. The research component of her grant focuses on developing strategies for studying biological treatment processes and improving designs to optimize the removal of industrial toxins from wastewater by integrating engineering, microbiology, and molecular biology principles.
Today, Love has laboratories in Virginia Techís Fralin Biotechnology Center and in ENES. Her research colleagues include Ann Stevens, assistant professor of biology, and Jane Duncan, a microbiology post-doctoral research associate. In addition to teaching civil and environmental engineering (CEE) courses, Love provides an environmental engineering perspective in microbiology courses in biology, and in biotechnology courses.
Why does Love believe this marriage of engineering and biology is so important to advances in wastewater engineering?
Industries dispose of their wastewater -- which often contains chemical compounds that resist biodegradation -- either by treating the wastewater on site and discharging it to a nearby stream or municipal treatment plant, or by discharging untreated effluent directly to a municipal treatment plant.
Chemical industry wastewater usually must be treated with a combination of physical/chemical and biological treatment processes, Love notes. For example, it is difficult to control the biodegradation of high concentrations of ammonium, which often occur in the wastewaters of the food, pharmaceutical, and chemical process industries. High concentrations of ammonium are removed by increasing the pH to convert ammonium into ammonia -- the gaseous form ? and then physically stripping the gas from the water using a stripping tower. Biodegradation is then employed to transform the residual ammonia into nontoxic elements.
As
a critical component in the treatment of industrial wastewater, biodegradation
offers notable advantages. "Letting microbes break down pollutants is almost
always less expensive than traditional physical/chemical treatment methods,"
Love explains. "Also, microbes can biodegrade or transform just about any
chemical, given the right environmental conditions. Figuring out what those
environmental conditions are is the challenge."
Successful biodegradation of many recalcitrant and toxic (xenobiotic) compounds requires use of both oxygen (aerobic) and oxygen-free (anaerobic) environments, Love says. Additionally, many industrial wastewaters contain more than one xenobiotic compound. Consequently, a consortium of participating microorganisms is often the best strategy for treating industrial wastewaters. Optimizing the effectiveness of such a diverse and complex system is a challenge, and requires an understanding of how the key microbial groups perform under all treatment conditions. "Wastewater engineers need to understand microbiology and molecular biology -- what goes on inside microbes -- to develop advances in this field," she says.
As part of her NSF project, Love is testing the ability of microbes in municipal biological sludge to biodegrade xenobiotic compounds. The microbes are being tested in bioreactors, which enable Love to control a range of conditions, such as alternating aerobic and anaerobic conditions, temperature, wastewater-flow rates, and the time microorganisms spend in the bioreactor. Love and her graduate students track the reactions of different populations of microbes to these changing conditions. Their observations provide clues about how biological wastewater treatment systems can be managed to maximize the breakdown of chemical pollutants.
At the same time, Love, Stevens, and Duncan are developing a biosensor protocol for use by the wastewater treatment industry. The biosensor project, sponsored by the NSF, industry, and the Virginia Tech research support program, is aimed at solving a major problem in wastewater treatment.
With current wastewater treatment systems, engineers can measure pH, temperature, and other factors that indicate the health of microorganisms that are consuming pollutants in wastewater. In some cases, these monitoring tools indicate if a "toxic shock" of xenobiotic chemicals has entered the bioreactor, or how well the microbes are performing after a shock has occurred. However, this standard approach offers little comfort because it does not indicate what caused the toxic shock, and allows a lot of room for surprises. Also, it is not uncommon for an industry to release a toxic shock to a municipal treatment plant without telling anyone downstream what is about to hit them.
The concept behind the biosensor is to directly monitor microbial activity under any environmental conditions (aerobic or anaerobic) and offer vital information on the nature of the toxicity "in seconds," Love says. This will tell wastewater engineers how much stress -- that is, exposure to toxins -- the microbes are experiencing.
"Being stressed doesnít mean that the microbes arenít biodegrading the toxins, however," Love notes. So, in addition to creating a biosensor that can provide a direct measurement of microbial activity, the researchers are using the biosensor to determine which chemical compounds and levels of those compounds stress wastewater treatment microbes to the point where treatment performance is affected.
Love is also working with John Little and John Novak of the CEE faculty on a pilot plant treatment study in Radford, Va., sponsored by Degremont North American Research and Development (DENARD, Inc.) of Richmond, Va. Using wastewater from the Radford municipal plant, they are testing a new domestic wastewater treatment technology. This is the first grant that DENARD, whose parent company is based in France, has awarded to a U.S. university for wastewater research.
"There will always be wastewater," Love remarks, "so I guess Iíll always have a research niche." But, aside from keeping busy as a researcher, she has an ultimate and ideal goal. "Thereís still a huge gap between those who design and operate manufacturing facilities and those who understand how to purify polluted waters generated by manufacturing processes," she says. "I want to play a part in helping the chemical industry integrate appropriate wastewater treatment and recycling technologies into the manufacturing mindset."