Subsurface vertical flow constructed wetlands with intermittent loading are considered as state of the art and can comply with stringent effluent requirements. It is usually assumed that microbial activity in the filter body of constructed wetlands, responsible for the removal of carbon and nitrogen, relies mainly on bacterially mediated transformations. However, little quantitative information is available on the distribution of bacterial biomass and production in the "black-box" constructed wetland. The spatial distribution of bacterial carbon utilization, based on bacterial (14)C-leucine incorporation measurements, was investigated for the filter body of planted and unplanted indoor pilot-scale constructed wetlands, as well as for a planted outdoor constructed wetland. A simple mass-balance approach was applied to explain the bacterially catalysed organic matter degradation in this system by comparing estimated bacterial carbon utilization rates with simultaneously measured carbon reduction values. The pilot-scale constructed wetlands proved to be a suitable model system for investigating microbial carbon utilization in constructed wetlands. Under an ideal operating mode, the bulk of bacterial productivity occurred within the first 10cm of the filter body. Plants seemed to have no significant influence on productivity and biomass of bacteria, as well as on wastewater total organic carbon removal.
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http://dx.doi.org/10.1016/j.watres.2007.10.011 | DOI Listing |
Water Res
December 2024
Xiamen Key Laboratory of Municipal and Industrial Solid Waste Utilization and Pollution Control, College of Civil Engineering, Huaqiao University, Xiamen, Fujian 361021, PR China; Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun, 130118, PR China. Electronic address:
As freshwater demand grows globally, using reclaimed water in natural water bodies has become essential. Constructed wetlands (CWs) are widely used for advanced wastewater treatment due to their environmental benefits. However, low carbon/nitrogen (C/N) ratios in wastewater limit nitrogen removal, often leading to eutrophication.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Earth and Planetary Sciences, University of California, Riverside, CA, 92521, USA.
The Salton Sea (SS), California's largest inland lake at 816 square kilometers, formed in 1905 from a levee breach in an area historically characterized by natural wet-dry cycles as Lake Cahuilla. Despite more than a century of untreated agricultural drainage inputs, there has not been a systematic assessment of nutrient loading, cycling, and associated ecological impacts at this iconic waterbody. The lake is now experiencing unprecedented degradation, particularly following the 2003 Quantification Settlement Agreement-the largest agricultural-to-urban water transfer in the United States.
View Article and Find Full Text PDFJ Environ Manage
December 2024
School of Geography and Environment & Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang, 330022, China. Electronic address:
The human geographical environment is a comprehensive setting formed by the interaction between human activities and the geographical environment, characterized by its complexity and vulnerability. Applying the digital twin method to create a new research model in a human geographical environment holds significant academic and practical value. This approach helps avoid disturbances in the real environment, deeply explores complex issues, and optimizes solutions for real-world geographical problems.
View Article and Find Full Text PDFJ Exp Bot
December 2024
School of Biological Sciences, The University of Western Australia, Perth, WA 6009, Australia.
During their lifespan, plants are often exposed to a broad range of stresses that change their redox balance and lead to accumulation of reactive oxygen species (ROS). The traditional view is that this comes with negative consequences to cells structural integrity and metabolism and, to prevent this, plants evolved a complex and well-coordinated antioxidant defence system that relies on the operation of a range of enzymatic and non-enzymatic antioxidants (AO). Due to the simplicity of measuring their activity, and in the light of the persistent dogma that stress-induced ROS accumulation is detrimental for plants, it is not surprising that enzymatic AO have often been advocated as suitable proxies for stress tolerance, as well as potential targets for improving tolerance traits.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
December 2024
School of Environment and Ecology, Jiangnan University, Wuxi, 214122, China.
Invasive alien plants pose a great threat to local plants and ecosystems. How to effectively alleviate this hazard is an unresolved issue. This study explored the carbon release characteristics of an invasive plant Spartina alterniflora and evaluated the ability of nitrogen removal from shrimp culture wastewater through constructing seawater wetland.
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