Concerns arise when excessive irrigation of the container crops grown in soilless media leads to leaching and loss of nutrients and chemicals in runoff. The resulting runoff can escape from production areas and have a negative impact on surface and ground water.
The presence of nutrients in runoff and concerns of their impact on surface and groundwater quality has undergone increasing interest and scrutiny from the public, environmental groups, governmental agencies, and elected officials. Since its enactment, the U.S. Environmental Protection Agency (EPA) has enforced provisions of the Clean Water Act related to point-source pollution. In 1999, the EPA began enforcing nonpoint source pollution controls, mandating that all states implement a Total Maximum Daily Load (TMDL) program for all watersheds and bodies of water.
Constructed wetlands (CWs) have been promoted as inexpensive, low-technology approaches to treating agricultural, industrial, and municipal wastewater to comply with increasingly stringent environmental regulations. CWs, or marshes built to treat contaminated water, incorporate soil and drainage materials, water, plants, and microorganisms. "Surface-flow" constructed wetlands resemble shallow freshwater marshes and generally require a large land area for wastewater treatment. More effective for greenhouse and nursery operations with limited production space and expensive land are a type of constructed wetland called "subsurface flow". Subsurface flow wetlands consist of a lined or impermeable basin filled with a coarse medium, typically gravel, and wetland plants. Wastewater flows horizontally or vertically below the surface of the media to prevent exposure to humans or wildlife.
Robert Polomski and his colleagues at Clemson University published a study in the June 2008 issue of HortScience that investigated the nitrogen and phosphorus removal potential by a vegetated, laboratory-scale subsurface flow system. "In this study, we investigated a cost-effective approach of reducing water treatment costs. Instead of traditional wetland plants, we found that commercially available aquatic garden plants can be used in a production/remediation system."
Over an eight-week period, five commercially available aquatic garden plants received a range of nitrogen and phosphorus that spanned the rates detected in nursery runoff. According to Polomski, "the results support the use of aquatic garden plants as aesthetic and economically viable alternatives to traditional wetland plants in constructed wetlands. Although more research is necessary to address other variables, the study concluded that the use of commercially produced plants in constructed wetlands has the potential to generate revenue for producers.
Michael W. Neff | EurekAlert!
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
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