Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Five-Story Biowall of Plants Serves as a Living Laboratory for Air Quality Research

05.10.2011
Just beyond the DNA-like helical staircase in Drexel University’s new Papadakis Integrated Sciences Building, the atrium’s great showpiece is a vertical wall of living plants, 20 feet wide, rising five stories (75 feet) in height – the largest such wall in North America and the only one at a U.S. university.

But the biowall is not just for show. It is an active living filter that removes volatile organic compounds (VOCs) from the air. Scientists and students at Drexel are studying the biowall and the plant and microbe communities responsible for its air filtration properties to get a better understanding of how it works.

Dr. Michael Waring, an assistant professor in the College of Engineering who specializes in indoor environmental engineering, will focus on the chemical and physical aspects of the living wall, while two biology faculty members from the College of Arts and Sciences, Dr. Jacob Russell and Dr. Shivanthi Anandan will focus on the wall’s biological functions.

About the Biowall
Biowalls such as the one at Drexel have been shown to reduce overall concentrations of VOCs, such as benzene, toluene, methyl-ethyl ketone, and formaldehyde, in the indoor air. Biowalls save energy by making it possible to recirculate a larger proportion of cleaner, conditioned air through the building, while bringing in less outdoor air that would require heating or cooling to match indoor conditions.

Drexel’s biowall consists of over 12 different varieties of tropical plants that grow in the absence of soil. The plant roots are embedded between two layers of woven, porous material similar to that of a kitchen scrubbing pad. Water trickles down the wall between these layers, providing plant roots with nutrients and hydration. The water is also key to filtering the air: Fans running behind the wall continuously pull contaminated indoor air through the biowall’s porous materials. As a result, VOCs naturally dissolve into the water and become available to bacteria and fungi on the plants’ roots. These microbes then consume and break down the VOCs into benign products, primarily carbon dioxide and water. As the microbes remove VOCs from the water, more VOCs can be absorbed from the circulating air, and the cycle continues. According to estimates by NEDLAW Living Walls, the company that designed and installed Drexel’s biowall, the wall is capable of generating between 16,000 and 30,000 cubic feet of ‘virtual’ outside air per minute.

While scientists have measured the overall results of this air filtration mechanism in biowalls, Waring points out that such measurements are coarse – measuring only the total concentration of VOCs in the air before and after passing through a biowall. Researchers don’t yet know specifically which chemicals are or are not being filtered out, while few have studied the microbes in plant roots that are responsible for breaking down VOCs. These are exactly the questions the Drexel team plans to address.

Drexel’s Biowall Research
Mimicking the Biowall in the Lab
In one part of their study, the researchers will evaluate a small-scale aeroponic growing system to determine if such bench-scale designs can be used for efficient research into biowall systems. “If we find out that it closely mimics microbial communities and VOC removal on the wall itself, this is something that researchers can use to set up in their labs to quickly do research for biowalls without needing the biowall itself,” Waring said.

In their laboratory apparatus, the researchers will suspend plants’ roots inside a chamber and measure the concentrations of chemicals in air flowing out of the chamber. Waring will then compare these measurements to samples taken from full-scale work on the biowall itself, using air samples drawn from each of eight sampling ports built into the back of the wall for research use. In their biological studies, described in more detail below, Russell and Anandan will compare the microbial communities in the model system with those found on the biowall.

“One of the really exciting things about this project is that we can test what the wall does in a real building rather than just presume that it works as well as it’s supposed to,” Waring said.

Studying Microbial Communities in the Plants’ Roots
While Waring’s efforts will indicate which plants harbor the root communities that are best at purifying the air, Russell and Anandan’s will shed light on the microbial species that are responsible for that purification.

The researchers will expose microbial communities to various types of chemicals in the aeroponic system in the lab. “We’re looking to see, when exposed to a particular chemical, do particular microbes proliferate?” Russell said.

To identify the microbes, Russell’s team will perform a kind of molecular barcoding to identify them by their DNA. The bar codes are much like a DNA fingerprint, but “instead of trying to match samples from a crime scene to an individual, we’re looking at a small microscopic community to understand everything that’s living there,” Russell said.

Russell will eventually examine not just what genes are present in the microbe communities, but what genes are actually expressed as the chemical environment changes. It is possible that microbes can turn on helpful genes when exposed to VOCs that help break down the chemicals more quickly.

While Russell’s work will help identify which microbial communities are present on the plants’ roots, Anandan will build on that effort by attempting to identify which specific microbial species or microbial communities are responsible for breaking down VOCs in the biowall.

Hundreds if not thousands of species of microbes may exist on the plants’ roots, but not all are actively involved in breaking down VOCs. According to Anandan, it is likely that a consortium of microbe species is responsible for the breakdown of chemicals, like “a conveyor belt of microbes, each with a specific step of breakdown.”

Anandan will cultivate living microbes in the lab and work to identify which microbes are active in these conveyor belts and what molecular processes they use to break down VOCs. Ultimately, it may be possible to grow populations of VOC-consuming microbes to use as a treatment on the roots of biowall plants that need a boost.

A Truly Integrated Sciences Building: Biowall Research in Building Design and Hands-On Education

Drexel’s biowall was designed and installed by NEDLAW Living Walls in collaboration with Toronto-based Diamond and Schmitt architects, who designed the building. Waring and other Drexel faculty members collaborated with the designers and architects to ensure that the physical structures of the building were fully compatible with their plans for research on the biowall. Eight sampling ports at locations behind the biowall, where researchers can collect air samples to measure the concentration of chemicals, were built into the structure to Waring’s specifications.

Biowall research is also integrated with hands-on education in the new building: Both Russell’s and Waring’s labs employ Drexel students through the University’s co-operative education program. The students work full-time as lab employees conducting hands-on research on the biowall and its plants and microbes.

Many of the science faculty at Drexel are integrating biowall science into the curriculum. Anandan said she incorporates the biowall into her instruction of freshman students. “This is biology in action,” Anandan said. “What you’re seeing is a biological application in real life, coupled with engineering, that works to do something that we think is going to improve human health.”

Learn more about the Papadakis Integrated Sciences Building at http://www.drexel.edu/now/professionals/releases/archive/2011/September/Drexel-Opens-Nations-First-University-Facility-with-Biowall/

Rachel Ewing | Newswise Science News
Further information:
http://www.drexel.edu

More articles from Ecology, The Environment and Conservation:

nachricht A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht Value from wastewater
16.08.2017 | Hochschule Landshut

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>