Articles de revues : « Natural and constructed wetlands »

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Kennedy, Gavin, et Tatiana Mayer. « Natural and Constructed Wetlands in Canada : An Overview ». Water Quality Research Journal 37, n^o 2 (1 mai 2002) : 295–325. http://dx.doi.org/10.2166/wqrj.2002.020.

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Abstract A review of freshwater wetland research in Canada was conducted to highlight the importance of these ecosystems and to identify wetland research needs. Both natural and constructed wetland systems are discussed. Natural wetlands are an important part of the Canadian landscape. They provide the habitat for a broad variety of flora and fauna and contribute significantly to the Canadian economy. It is estimated that the total value derived from consumptive and non-consumptive activities exceeds $10 billion annually. The past decades have witnessed the continued loss and degradation of wetlands in Canada. In spite of recent protection, Canadian wetlands remain threatened by anthropogenic activities. This review shows that more research on fate and transport of pollutants from urban and agricultural sources in wetland systems is needed to better protect the health and to assure the sustainability of wetlands in Canada. Furthermore, improved knowledge of hydrology and hydrogeochemistry of wetlands will assure more effective management of these ecosystems. Lastly, better understanding of the effect of climate change on wetlands will result in better protection of these important ecosystems. Constructed wetlands are man-made wetlands used to treat non-point source pollution. The wetland treatment technology capitalizes on the intrinsic water quality amelioration function of wetlands and is emerging as a cost-effective, environmentally friendly method of treating a variety of wastewaters. The use of wetland technology in Canada is, however, less common than in the U.S.A. A number of research needs has to be addressed before the wetland treatment technology can gain widespread acceptance in Canada. This includes research pertaining to cold weather performance, including more monitoring, research on design adaptation and investigation of the effects of constructed wetlands on wildlife.

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Gopal, Brij. « Natural and Constructed Wetlands for Wastewater Treatment : Potentials and Problems ». Water Science and Technology 40, n^o 3 (1 août 1999) : 27–35. http://dx.doi.org/10.2166/wst.1999.0130.

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Wetlands are being considered increasingly important for wastewater treatment because of the ability of many wetland plants to absorb large amounts of nutrient and a variety of toxic substances. The paper highlights the physical, chemical and biological processes which contribute to the improvement of water quality, and the distinction between natural and constructed wetlands. The impacts of long-term wastewater disposal on the biotic changes, reduction in treatment efficiency, and wetland processes such as production of trace gases, are pointed out. Constraints in using wetlands, for wastewater treatment, such as poor understanding of the natural wetland functions and responses of native plants and animals to wastewater, particularly in developing countries, are briefly discussed. It is suggested that while the possibilities for using constructed wetlands based on native species for small communities are explored, greater emphasis should be laid on the restoration of lost and degraded wetlands, especially the river floodplains, lake littorals and coastal wetlands, which can help check pollution from non-point sources.

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Sukhla, Prof Saurabh M., Mr Khatik Sufiyan Jameel, Mr Prasad Abhishek Ramesh, Mr Satpute Nikhil Bhairavnath, Mr Pawar Pravin Surendra, Mr Mitthe Mayur Ramnath, Prof Prashant G. Chavan et Prof Pravin S. Chavanke. « Wastewater Treatment Using Constructed Wetland System ». International Journal for Research in Applied Science and Engineering Technology 10, n^o 5 (31 mai 2022) : 1303–6. http://dx.doi.org/10.22214/ijraset.2022.42463.

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Abstract: Natural wetland such as marshes ,swamps and bogs protect water quality . constructed or artificial wetland system mimic the treatment that occurs in natural wetlands by rellyilng on plants and a combination of naturally occurring biological , chemical and physical processes to remove pollutants from water . As of 1999,there were more than 500 constructed wetland in Europe and 600 in north America . constructed wetland are a less energy intensive and more environmentally sound way of treating waste water and conserving potable water . The first single family home constructed wetland in southern Nevada was completed Eighth years ago. A constructed wetland (CW) is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development constructed wetlands also act as a biofilter and/or can remove a range of pollutants (such as organic matter, nutrients, pathogens, heavy metals) from the water. Constructed wetlands are designed to remove water pollutants such as suspended solids, organic matter and nutrients (nitrogen and phosphorus).

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Berego, Yohannes Seifu, Solomon Sorsa Sota, Mihret Dananto Ulsido et Embialle Mengistie Beyene. « Treatment Performance Assessment of Natural and Constructed Wetlands on Wastewater From Kege Wet Coffee Processing Plant in Dale Woreda, Sidama Regional State, Ethiopia ». Environmental Health Insights 16 (janvier 2022) : 117863022211427. http://dx.doi.org/10.1177/11786302221142749.

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Constructed wetlands are engineered systems built to use natural processes and remove pollutants from contaminated water in a more controlled environment. The research was an experimental research carried out to assess the effectiveness of natural and constructed wetland systems in the treatment of coffee wastewater. The 2 vertical flow constructed wetland was built. The first wetland covered an area of 132 m2. It has 12 m width and 11 m length. Open space is constructed between 2 constructed wetlands with a dimension of 11 m × 3 m × 1 m. The second wetland was constructed and its function is similar to the first one, from this wetland water is discharged to the river. The construction of the wetland is accomplished by constructing 20 cm wide furrows with a spacing of 30 cm. Vetiver grasses have planted with a spacing of 20 cm intervals. The physicochemical data were recorded, organized, and analyzed using R software (version 4.1) and Microsoft Excel. Data were processed using parametric (one-way ANOVA) and nonparametric (Mann-Whitney’s U test) statistical tests of homogeneity. One-way analysis of Variance (ANOVA) was used to determine the significance of differences in variations in physicochemical variables within the constructed wetland sites. Tukey’s multiple comparisons for differences between means were also assessed. Findings indicated that a natural wetland had a mean influent and effluent of total suspended solids (TSS) of 2190.78 ± 448.46 mg/l and 972.67 ± 234.312 mg/l, respectively. A Mann-Whitney U test revealed that TSS were significantly higher in natural wetland (median = 1551.50) compared to constructed wetland (median = 922.5), U = 676.5, z = −2.435, P = .015, r = .257. Natural wetlands had a mean influent of biological oxygen demand (BOD) was 4277.94 ± 157.02 mg/l, while in the effluent of BOD it was 326.83 ± 112.24 mg/l. While in constructed wetland it was 4192.4 ± 191.3 mg/l, 782.72 ± 507.6 mg/l, and 88.28 ± 20.08 mg/l in influent, middle, and effluent respectively. Average chemical oxygen demand (COD) value at influent in natural wetlands was 8085.61 ± 536.99 mg/l and in the effluent it was 675.33 ± 201.4 mg/l. In constructed wetland, it was found to be 8409.8 ± 592.9, 1372.6 ± 387.94, and 249.0 ± 7.68 for influent, middle, and effluent respectively. Comparatively, the purification efficiency of organic pollutants (TSS, BOD, and COD) of constructed wetlands was better than natural wetlands, whereas natural wetlands had better purification efficiency of nitrogen compounds such as ammonium, nitrite, and nitrate. On average, removal rates for nitrogen compounds were 39.53% and −24.41% for ammonium, 79.44% and 55.4% for nitrite, and 68.90% and 60.6% for nitrate in natural and constructed wetlands respectively, while the phosphate removal rate was 43.17% and 58.7% in natural and constructed wetlands, respectively. A Mann-Whitney U test revealed that there is no significance difference in nitrite, nitrate, ammonium, and phosphate concentration between natural and constructed wetlands( P > .05). Based on these results, both systems of treatment were effective in treating the coffee effluent since most of the values obtained were below the permissible EEPA limits. Even though the constructed wetland treatment plant performed better overall, in comparison, the natural wetlands had better purification efficiency for nitrogen compounds like ammonium, nitrite, and nitrate and the constructed wetlands had better purification efficiency for organic pollutants (TSS, BOD, and COD).

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Saxena, Shalini. « EFFICACY OF PHRAGMITE KARKA PLANT IN CONSTRUCTED WETLAND SYSTEM ». International Journal of Research -GRANTHAALAYAH 3, n^o 9SE (30 septembre 2015) : 1–5. http://dx.doi.org/10.29121/granthaalayah.v3.i9se.2015.3177.

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Wetlands, either constructed or natural, offer a cheaper and low-cost alternative technology for wastewater treatment. A constructed wetland system that is specifically engineered for water quality improvement as a primary purpose is termed as a ‘Constructed Wetland Treatment System’ (CWTS). In the past, many such systems were constructed to treat low volumes of wastewater loaded with easily degradable organic matter for isolated populations in urban areas. However, widespread demand for improved receiving water quality, and water reclamation and reuse, is currently the driving force for the implementation of CWTS all over the world. Recent concerns over wetland losses have generated a need for the creation of wetlands, which are intended to emulate the functions and values of natural wetlands that have been destroyed. Natural characteristics are applied to CWTS with emergent macrophyte stands that duplicate the physical, chemical and biological processes of natural wetland systems. The number of CWTS in use has very much increased in the past few years. The use of constructed wetlands is gaining rapid interest. Most of these systems cater for tertiary treatment from towns and cities. They are larger in size, usually using surface-flow system to remove low concentration of nutrient (N and P) and suspended solids. However, in some countries, these constructed wetland treatment systems are usually used to provide secondary treatment of domestic sewage for village populations. These constructed wetland systems have been seen as an economically attractive, energy-efficient way of providing high standards of wastewater treatment by the help of Phragmite karka plant. Typically, wetlands are constructed for one or more of four primary purposes: creation of habitat to compensate for natural wetlands converted for agriculture and urban development, water quality improvement, flood control, and production of food and fiber.

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Hadidi, Luna Al. « CONSTRUCTED WETLANDS A COMPREHENSIVE REVIEW ». International Journal of Research -GRANTHAALAYAH 9, n^o 8 (13 septembre 2021) : 395–417. http://dx.doi.org/10.29121/granthaalayah.v9.i8.2021.4176.

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Constructed wetlands are wastewater treatment systems composed of one or more treatment cells in a building designed and constructed to provide wastewater treatment. Constructed wetlands are classified into two types: free water surface (FWS) wetlands (also known as surface flow wetlands) closely resemble natural wetlands in appearance because they contain aquatic plants that are rooted in a soil layer on the bottom of the wetland and water flows through the leaves and stems of plants. Subsurface flow wetlands (SSF) or known as a vegetated submerged bed (VSB) systems do not resemble natural wetlands because they have no standing water. They contain a bed of media (such as crushed rock, small stones, gravel, sand, or soil) that has been planted with aquatic plants. When properly designed and operated, wastewater stays beneath the surface of the media, flows in contact with the roots and rhizomes of the plants, and is not visible or available to wildlife. Constructed wetlands are an appropriate technology for areas where inexpensive land is generally available and skilled labor is less available. In this paper, a comprehensive review covered types, characteristics, design variation and considerations, limitations, and the advantages and disadvantages of constructed wetlands.

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Saxena, Shalini. « CLEAN DEVELOPMENT MECHANISM AND CARBON CYCLING OF SEWAGE WASTE BY CONSTRUCTED WETLANDS ». International Journal of Research -GRANTHAALAYAH 10, n^o 4 (17 mai 2022) : 209–15. http://dx.doi.org/10.29121/granthaalayah.v10.i4.2022.4517.

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Wetlands, either constructed or natural, offer a cheaper and low-cost alternative technology for wastewater treatment. A constructed wetland system that is specifically engineered for water quality improvement as a primary purpose is termed as a ‘Constructed Wetland Treatment System’ (CWTS). In the past, many such systems were constructed to treat low volumes of wastewater loaded with easily degradable organic matter for isolated populations in urban areas. However, widespread demand for improve in water quality, and water reclamation and reuse, is currently the driving force for the implementation of CWTS all over the world. Recent concerns over wetland losses have generated a need for the creation of manmade wetlands, which are intended to emulate the functions and values of natural wetlands that have been destroyed. Natural characteristics are applied to CWTS with emergent macrophyte stands that duplicate the physical, chemical and biological processes of natural wetland systems. The number of CWTS in use has very much increased in the past 50 years. The use of constructed wetlands is gaining rapid interest. Most of these systems cater for tertiary treatment from towns and cities. They are larger in size, usually using surface-flow system to remove low concentration of nutrient (N and P) and suspended solids. However, in some countries, these constructed wetland treatment systems are usually used to provide secondary treatment of domestic sewage for village populations. These constructed wetland systems have been seen as an economically attractive, energy-efficient way of providing high standards of wastewater treatment. Typically, wetlands are constructed for one or more of four primary purposes: creation of habitat to compensate for natural wetlands converted for agriculture and urban development, water quality improvement, flood control, and production of food and fiber (constructed aquaculture wetlands). In present research the sewage water is treated by constructing Horizontal sub – surface flow constructed wetland, and reed grass is used as vegetation to treat waste and make the sewage waste water clean.

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King, Susan K., et Stephen C. Richter. « Reproductive Ecology and Nesting Site Characteristics of Four-Toed Salamanders (Hemidactylium scutatum) in Natural and Constructed Upland-Embedded Wetlands on the Appalachian Plateau, Kentucky ». Diversity 14, n^o 11 (18 novembre 2022) : 995. http://dx.doi.org/10.3390/d14110995.

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Many forested freshwater wetlands have been altered or destroyed, and wetlands are constructed to offset loss. However, they do not always replace the function of natural wetlands. It is important to understand how features of the habitat differ between types of wetlands and whether constructed wetlands provide an adequate habitat for species adapted to natural wetlands. Our objectives were to measure the characteristics of Four-toed Salamanders’ nesting habitat and determine which factors contribute to the abundance of eggs and nests in natural and constructed upland-embedded wetlands within a ridgetop ecosystem in eastern Kentucky. We located and examined characteristics for 207 nests in twelve wetlands and measured variables at the nest level and at the wetland level. The best predictor of the number of eggs and number of nests was amount of moss at the wetland. These measures of reproductive effort were similar between types of wetlands, but the number of eggs per nest was higher in constructed wetlands and inversely related to amount of moss, highlighting a deficit in nesting habitat. Research of embryonic and larval survival is needed but based on data from other amphibian species in this system, we predict that the survival of Four-toed Salamanders’ larvae is low in constructed wetlands with permanent hydrology. Restoration of constructed wetlands should address the need for moss as nesting substrate and drying of the wetland to reduce the abundance and diversity of predators of larvae.

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Jethwa, Dr Kruti B. « A Review on Design Basis for Constructed Wetlands for Wastewater Treatment ». International Journal for Research in Applied Science and Engineering Technology 9, n^o VIII (15 août 2021) : 373–77. http://dx.doi.org/10.22214/ijraset.2021.37163.

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Since last few years Constructed Wetlands (CWs) are being used to treat secondary or tertiary municipal or domestic wastewater effluents have been recognized as an effective means of “green technology” for wastewater treatment. Constructed wetlands (CWs) provide a natural way for simple, inexpensive, and robust wastewater treatment. The idea of natural management systems is the restoration of disturbed ecosystems and their sustainability for remuneration to nature. The Constructed wetlands (CWs) are designed to copy natural wetland systems, utilizing wetland plants, soil and associated microorganisms using various biological, physicochemical processes to remove unwanted constituents from wastewater effluents. This review paper studies various types of constructed wetlands, i.e., surface or subsurface, vertical or horizontal flow and their type of operation, i.e., continuous, batch or intermittent flow, loading rate, selection of plants and wastewater characteristics that affect the treatment efficiency. The design models with their suitability for various parameters and operational conditions such as Darcy’s equation, Kadlec and Knight Model (K-C* model), Arrhenius equation, and population equivalent calculation have been discussed. Lastly, future research requirements have been considered.

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Ge, Xiu Li, Ren Qing Wang et Jian Liu. « The Comparison of the Community Features between the Constructed Wetland and the Natural Wetland in Nansi Lake ». Advanced Materials Research 518-523 (mai 2012) : 5238–43. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5238.

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Thirteen typical plant communities were investigated in Xinxuehe constructed wetland restored for five years and in Gaolou natural wetland restored naturally for eight years. Both wetlands are located in Nansi Lake area. The species composition, coverage, aboveground biomass and biodiversity indices were compared between the communities from the constructed wetland and the natural wetland. The results showed that the constructed wetland and the natural wetland had similar emergent species and typical species of their own, however neither coverage nor aboveground biomass showed significant differences. In the meanwhile, we found that the biodiversity of natural wetland is relatively higher than the constructed wetland. For the wetland restoration and the water quality quick improving, it is suitable to use artificial ways to promote the restoration of wetlands which converted from the farmland in Nansi Lake area; in the other hand, the natural wetland restoration is more valuable for the biodiversity conservation in the long run.

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Peterson, Hans G. « Use of constructed wetlands to process agricultural wastewater ». Canadian Journal of Plant Science 78, n^o 2 (1 avril 1998) : 199–210. http://dx.doi.org/10.4141/p97-142.

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Constructed wetlands are emerging as a serious challenge to conventional wastewater treatment because of lower construction and operating costs, less requirement for trained personnel, more flexibility, and lower susceptibility to variations in waste loading rates. Water quality improvements can be achieved by removal of plant nutrients, such as N and P, organics (natural and manmade) as well as inorganic contaminants. Wetland treatment is now advocated by regulatory agencies and has been determined as the technology of choice by municipalities and industries required to meet stringent discharge regulations. These same regulations have not usually been imposed on the agricultural community, but deteriorating water sources will likely change this regulatory anomaly. Use of this technology in treating agricultural wastewater is still in its infancy with few, although rapidly expanding, applications. This paper aims to highlight different aspects of wetland treatment by exploring its use for the treatment of agricultural run-off as well as wastewater from the agri-food industry. It is concluded that natural wetlands will be quite limited in absorbing agricultural wastewater while constructed wetlands can be designed for optimum pollutant removal. Key words: Constructed wetlands, wastewater treatment, agriculture, food processing, nutrient removal, nitrogen, phosphorus, organics

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Li, Han, Radmila Petric, Zinah Alazzawi, Jake Kauzlarich, Rania H. Mahmoud, Rasheed McFadden, Niklas Perslow et al. « Four Years Continuous Monitoring Reveals Different Effects of Urban Constructed Wetlands on Bats ». Land 10, n^o 10 (14 octobre 2021) : 1087. http://dx.doi.org/10.3390/land10101087.

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Proactive artificial wetland constructions have been implemented to mitigate the loss of wetlands and their ecosystem services. As wetlands are habitats for bats, short-term (one or two years) studies find that constructed wetlands can immediately increase local bat activity and diversity. However, it is not clear how constructed wetlands affect bats through time while the wetlands are aging. We collected four years of continuous bat acoustic monitoring data at two constructed wetlands in an urban park in Greensboro, NC, USA. We examined bat activity and community composition patterns at these wetlands and compared them with reference sites in the city. With four years of data, we found that the effects of constructed wetlands were both habitat- and species-specific. The wetland in forests significantly increased bat activity, while the wetland in the open grass altered bat community composition. Specifically, in terms of species, we found that over time, constructed wetlands no longer attracted more big brown, silver-haired, or evening bats than control sites while the wetlands aged, highlighting the need to study broadly how each bat species uses natural and artificial wetlands. We emphasize the importance of long-term monitoring and the periodical evaluation of wildlife conservation actions.

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Pankratz, S., T. Young, H. Cuevas-Arellano, R. Kumar, R. F. Ambrose et I. H. Suffet. « The ecological value of constructed wetlands for treating urban runoff ». Water Science and Technology 55, n^o 3 (1 février 2007) : 63–69. http://dx.doi.org/10.2166/wst.2007.073.

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The Sweetwater Authority's urban runoff diversion system (URDS) comprises constructed wetlands on a hillside between the town of Spring Valley and the Sweetwater Reservoir, California, USA. The URDS were designed to divert dry-weather and first-flush urban runoff flows from the Sweetwater reservoir. However, these constructed wetlands have developed into ecologically valuable habitat. This paper evaluates the following ecological questions related to the URDS: (1) the natural development of the species present and their growth pattern; (2) the biodiversity and pollutant stress on the plants and invertebrates; and (3) the question of habitat provided for endangered species. The URDS wetlands are comprised primarily of rush (Scirpus spp.) and cattails (Typha spp.). This vegetative cover ranged from 39–78% of the area of the individual wetland ponds. Current analyses of plant tissues and wetland sediment indicates the importance of sediment sorption for metals and plant uptake of nutrients. Analyses of URDS water following runoff events show the URDS wetlands do reduce the amount of nutrients and metals in the water column. Invertebrate surveys of the wetland ponds revealed lower habitat quality and environmental stress compared to unpolluted natural habitat. The value of the wetlands as wildlife habitat is constrained by low plant biodiversity and pollution stress from the runoff. Since the primary Sweetwater Authority goal is to maintain good water quality for drinking, any secondary utilization of URDS habitat by species (endangered or otherwise) is deemed an added benefit.

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Kadlec, Robert H. « Deterministic and stochastic aspects of constructed wetland performance and design ». Water Science and Technology 35, n^o 5 (1 mars 1997) : 149–56. http://dx.doi.org/10.2166/wst.1997.0185.

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Potato processing wastewater contains high concentrations of COD, TSS and TKN. A combination of surface flow wetlands, intermittent vertical flow wetlands, ponds and land application has been used for treatment. This engineered natural system balances irrigation requirements, nitrogen supply and seasonal growth patterns to provide effective year-round operation. A first pilot wetland was operated to determine operability, effectiveness, and plant survival at high COD and nitrogen concentrations. A second pilot system of four wetlands in series was operated to obtain design and operating information. Two surface flow wetlands provided TSS and COD reduction, and ammonified the organic nitrogen. Subsequently, nitrification occurred in the vertical flow wetlands, followed by denitrification in a surface flow wetland. The design target was a balanced nitrogen and irrigation supply for application to crops. Winter storage as used to match the crop application period to the growing season. Both pilot projects met design objectives, and a full scale system has begun operation.

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Bhamidimarri, R., A. Shilton, I. Armstrong, P. Jacobson et D. Scarlet. « Constructed Wetlands for Wastewater Treatment : The New Zealand Experience ». Water Science and Technology 24, n^o 5 (1 septembre 1991) : 247–53. http://dx.doi.org/10.2166/wst.1991.0131.

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The use of constructed wetlands which mimic natural marshlands, represents an innovative approach to wastewater treatment. They make use of diverse ecological mechanisms to renovate wastewater. They are inexpensive to construct and operate with minimal energy requirements. Unlike the conventional technologies, wetlands provide low volumetric reaction rates and therefore are suitable for small-scale applications. The majority of constructed wetlands in New Zealand are used for the treatment of domestic wastewaters from small communities for secondary treatment and pathogen removal. There are over 20 constructed wetlands in New Zealand receiving wastewater flow rates ranging from 7.5m3/day to around 4500m3/day. Both surface-flow and subsurface-flow wetlands are used. The performance data from three wetland systems treating septic tank effluents are presented and their treatment efficiences are discussed.

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Drayer, Andrea N., et Stephen C. Richter. « Physical wetland characteristics influence amphibian community composition differently in constructed wetlands and natural wetlands ». Ecological Engineering 93 (août 2016) : 166–74. http://dx.doi.org/10.1016/j.ecoleng.2016.05.028.

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Gao, Pan, et Chao Zhang. « Study on Phosphorus Removal Pathway in Constructed Wetlands with Thermally Modified Sepiolite ». Sustainability 14, n^o 19 (1 octobre 2022) : 12535. http://dx.doi.org/10.3390/su141912535.

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Constructed wetlands, as natural sewage treatment ecosystems, have been widely used in the fields of rural domestic sewage and sewage plant tailwater treatment. However, the synchronous removal of phosphorus in most constructed wetlands is not ideal. This study aimed to prepare thermally modified sepiolites with high phosphorus adsorption capacities and design a constructed wetland based on them. Thermal modification was adopted to enhance the adsorption capacity of sepiolite based on its high specific surface area and ion exchange capacity. The physicochemical properties and adsorption performance of thermally modified sepiolite were studied. The results showed that the specific surface area and adsorption capacity of thermally modified sepiolite were higher than those of natural sepiolite, reaching 19.494 mg·g−1. The concentration of effluent and the removal of constructed wetlands based on thermally modified sepiolite was 0.07 mg·g−1 and 91.05%. An analysis of the phosphorus forms in constructed wetlands proved that the main phosphorus removal pathway is the adsorption of substrate, and the form of phosphorus was mainly Ca/Mg-P and Fe/Al-P.

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Nikolic, Vladimir, Dragan Milicevic et Slobodan Milenkovic. « Wetlands, constructed wetlands and theirs role in wastewater treatment with principles and examples of using it in Serbia ». Facta universitatis - series : Architecture and Civil Engineering 7, n^o 1 (2009) : 65–82. http://dx.doi.org/10.2298/fuace0901065n.

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Wetlands protection programs, as a relative new approach in surface water and ground-water protection The types of Wetlands, theirs mechanism of removal nutrients and other pollutants from water are shown in this work paper. Wetland restoration, the renewal of natural and historical wetlands that have been lost or degraded, is a growing activity. Constructed wetlands, as treatment systems that use natural processes, are very adequate and highly efficient, low cost way in wastewater treatment for small communities, point pollution sources, depending, of course on conditions and adequate land spaces near those places. Some examples from Serbia of this way and approach are shown.

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Kao, C. M., et M. J. Wu. « Control of non-point source pollution by a natural wetland ». Water Science and Technology 43, n^o 5 (1 mars 2001) : 169–74. http://dx.doi.org/10.2166/wst.2001.0278.

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Wetland creation and restoration is a reliable and efficient technology for the remediation of contaminated water. Knowledge from the natural wetland systems would be necessary to enhance the operational efficiency of constructed wetlands. In this study, a mountainous wetland located in McDowell County, North Carolina, USA was selected to demonstrate the effects of the natural filtration and restoration system on the maintenance of surface water quality. The hydraulic retention time (HRT) for the wetland was 10.5 days based on the results from a dye release study. Water quality monitoring of the wetland was conducted from May to August 1997. One major storm event and baseline water quality samples were collected and analyzed. Analytical results indicate that this wetland removed a significant amount of non-point source (NPS) pollutants [more than 80% N removal, 91% of total suspended solid removal, 59% of total phosphorus removal, and 66% of chemical oxygen demand (COD) removal] caused by the studied storm event. Sediment accretion monitoring results indicate that the accretion rate in the wetland was only 4 mm/year. Therefore, the wetland would require 100 years to fill at the measured sediment accretion rate. The high organic content of sediments (16%) indicates that the wetland is building the characteristic organic layer on the bottom of the wetland. Results from this study would be very useful in the maintenance of natural wetlands and design of constructed wetlands for water treatment.

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Overton, Olivia Celeste, Leif Hans Olson, Sreemala Das Majumder, Hani Shwiyyat, Mary Elizabeth Foltz et Robert William Nairn. « Wetland Removal Mechanisms for Emerging Contaminants ». Land 12, n^o 2 (14 février 2023) : 472. http://dx.doi.org/10.3390/land12020472.

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In recent decades, previously unobserved trace compounds have become more widely detected in wastewater treatment effluents and freshwater ecosystems. Emanating from various sources and presenting potential human health and ecological risks at much lesser concentrations than traditional contaminants, detection of “emerging contaminants” has increased with improvements in analytical techniques. The behavior of emerging contaminants in wetlands is a topic of increasing interest, as natural wetlands are known to transform and sequester pollutants and constructed or treatment wetlands are widely utilized to address elevated concentrations of constituents of concern. Both natural and constructed wetlands are complex biogeochemical systems with interrelated abiotic and biotic mechanisms leading to the removal of emerging contaminants. A literature review was performed to assess the current state of knowledge of various wetland mechanisms involved in removing these contaminants from surface waters and effluents. The primary mechanisms discussed in the literature are sorption, photodegradation, microbial biodegradation and phytoremediation. The most influential mechanisms are dependent on the properties of the contaminants and wetland systems studied. Common trends exist for different constructed wetland designs to leverage various mechanisms based on hydrology, substrate and vegetation plantings. Much remains to be understood about the various processes occurring in wetlands as they relate to emerging contaminant removal. Improving the understanding of the potential role of wetland mechanisms can help manage this environmental challenge more effectively.

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Mitchell, D. S., A. J. Chick et G. W. Raisin. « The use of wetlands for water pollution control in Australia : an ecological perspective ». Water Science and Technology 32, n^o 3 (1 août 1995) : 365–73. http://dx.doi.org/10.2166/wst.1995.0159.

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The potential use of natural and constructed wetlands to treat rural and urban wastewaters and run-off has been under active investigation in Australia by the authors and others associated with them for about 15 years. The results of these investigations will be briefly summarised in relation to factors affecting their performance and their application for management of water pollution. Investigations have included rigorous experimentation with wetland microcosms, calculation of nutrient balances for natural and artificial wetlands, fundamental research on the role of wetland plants, the construction of experimental wetlands of various designs at a pilot scale, and the installation of operating systems. The results confirm the potential of wetland systems to ameliorate water quality but do not demonstrate how to do this consistently under normal day-to-day operating conditions. Issues that now need to be addressed include hydraulic short-circuiting, the role and management of the wetland plants, the extent to which constructed systems should mimic natural systems, and problems associated with scaling up from successful experimental systems to full scale operating treatment plants.

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Li, Heying, Jiayao Wang, Jianchen Zhang, Fen Qin, Jiyuan Hu et Zheng Zhou. « Analysis of Characteristics and Driving Factors of Wetland Landscape Pattern Change in Henan Province from 1980 to 2015 ». Land 10, n^o 6 (27 mai 2021) : 564. http://dx.doi.org/10.3390/land10060564.

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The study of the temporal and spatial evolution of wetland landscapes and its driving factors is an important reference for wetland ecological restoration and protection. This article utilized seven periods of land use data in Henan Province from 1980 to 2015 to extract the spatial distribution characteristics of wetlands and analyze the temporal and spatial changes of wetlands in Henan Province. Transfer matrix, landscape metrics, correlation analysis, and redundancy analysis were applied to calculate and analyze the transformation types and area of wetland resources between all consecutive periods, and then the main driving factors of wetland expansion/contraction were explored. First, the total wetland area in Henan Province increased by 28% from 1980 to 2015, and the increased wetland area was mainly constructed wetlands, including paddy field, reservoir and pond, and canal. Natural wetlands such as marsh, lake, and floodplain decreased by 74%. Marsh area declined the most during 1990–1995, and was mainly transformed into floodplain and “Others” because of agricultural reclamation, low precipitation, and low Yellow River runoff. The floodplain area dropped the most from 2005 to 2010, mainly converted to canals and “Others” because of reclamation, exploitation of groundwater, the construction of the South–to–North Water Transfer Project, and recreational land development. Second, the results of correlation analysis and redundancy analysis indicated that economic factors were positively correlated with the area of some constructed wetlands and negatively correlated with the area of some natural wetlands. Socioeconomic development was the main driving factors for changes in wetland types. The proportion of wetland habitat in Henan Province in 2015 was only 0.3%, which is low compared to the Chinese average of 2.7%. The government should pay more attention to the restoration of natural wetlands in Henan Province.

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Wang, Bo, Huan Hui Huang et Ping Bin Jin. « The Roles and Applications of Wetlands in Eco-City Construction — Taking Ruian City as an Example ». Advanced Materials Research 518-523 (mai 2012) : 6088–96. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.6088.

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In the process of urbanization, We always neglect the issue of environmental protection. In recognition of this problem, we begin to think about the way to solve it. We find that wetlands have important ecological and environmental functions, which play an important role in maintaining regional ecological balance and the conservation of biological diversity. Especially, urban wetlands are playing an irreplaceable role in eco-city construction. The article takes Ruian city as an example to discuss the utility of natural wetland and constructed wetland in eco-city construction. We conclude that to construct an eco-city, Ruian should focus on pollution control, at the same time, we can make use of natural wetland and constructed wetland to make Ruian more beautiful and ecological.

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Lott, R. Brandon, et Randall J. Hunt. « Estimating evapotranspiration in natural and constructed wetlands ». Wetlands 21, n^o 4 (décembre 2001) : 614–28. http://dx.doi.org/10.1672/0277-5212(2001)021[0614:eeinac]2.0.co;2.

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Chen, Yaoping, Kisoo Park et Youngchul Kim. « Particle retention in compact constructed wetlands treating highway stormwater ». Water Science and Technology 69, n^o 7 (24 janvier 2014) : 1440–46. http://dx.doi.org/10.2166/wst.2014.026.

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Three pilot-scale compact constructed wetland systems were constructed to treat stormwater from a highway. They each comprised a sedimentation tank, and a vertical flow (VF) wetland bed equipped with a recirculation device. The VF wetland beds were filled with woodchip, pumice and volcanic gravel, respectively. According to the analysis of the particle size distributions (0.52–500 μm), the predominant particles in stormwater ranged in size from 0.52–30 μm. In the sedimentation tank, with a 24 h settling time, the settling efficiencies of the particles increased with increasing particle size. In the VF wetland beds, further capture of the particles was achieved; however, the woodchip and volcanic gravel wetlands displayed relatively low trapping of micro-particles, due to the natural properties of the substrates. Recirculation caused a positive effect on the retention of particles in the woodchip wetland. Due to the employment of a pre-treatment tank and the high porosity of materials, the accumulated solids occupied very low proportions of the pore volume in the wetland substrates. The results also showed that the accumulation of copper, zinc and lead do not pose a problem for the disposal of the substrates when the wetlands reach the end of their operational lifetime.

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Bradley, Jennifer C., et J. M. Zajicek. « Wetland Plants for Wastewater Treatment : A Tremendous Opportunity for Horticulture ». HortScience 31, n^o 4 (août 1996) : 594c—594. http://dx.doi.org/10.21273/hortsci.31.4.594c.

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A current trend in environmental practices concerns using constructed wetlands for wastewater treatment. The ecological values of wetlands have long been known. Wetland plants aid in the treatment of water pollutants by improving conditions for microorganisms and by acting as a filter to absorb trace metals. Wetlands now are being considered for industrial, municipal, and home wastewater treatment. Constructed wetlands are an economical and environmentally sound alternative for treating wastewater. These constructed “cells” are designed to function like natural wetlands. In constructed wetlands, water flow is distributed evenly among plants in a cell where physical, chemical, and biological reactions take place to reduce organic materials and pollutants. Increasing numbers of environmentally conscious homeowners are installing wetland wastewater treatment systems in their backyards with the aid of licensed engineers. This installation is occurring despite of the lack of educational materials to aid in site selection, selection of appropriate plant materials, and long-term maintenance. Traditional wetland plant species currently are being selected and planted in these sites, and the resulting effect is often an unsightly marsh appearance. With increasingly more homeowners opting for this alternative system, a strong need exists for educational materials directed at this audience. Therefore, educational resources that can provide information to the public regarding the benefits of wetland wastewater systems, while promoting aesthetically pleasing ornamental plant species is needed. A hands-on guide for installing constructed wetlands, a home page on the World Wide Web, and an instructional video currently are being developed at Texas A&M Univ. These technologies will be demonstrated and the values, needs, and opportunities available for the horticultural industry in the area of wetland construction will be discussed.

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Peng, Ju Wei, et Xiang Kui Han. « Study on the Surface Flow Constructed Wetland Wastewater Treatment of Furfural Wastewater ». Advanced Materials Research 281 (juillet 2011) : 233–36. http://dx.doi.org/10.4028/www.scientific.net/amr.281.233.

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According to the characteristics of furfural wastewater, by production enterprises located in low-lying saline land transformed into a surface flow constructed wetlands, the waste water in the wetland approach to natural consumption, no efflux, treated waste water equal to the wetland wastewater by natural evaporation, plant transpiration and plant storage Volume. Research show that, after wetland treatment the wastewater COD removal rate to an average of 94%, TN removal rate to an average of 65%, PH value of treated wastewater is 6.22, the use of surface flow constructed wetland wastewater treatment is feasible ecological processing technology for furfural.

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Noller, B. N., P. H. Woods et B. J. Ross. « Case Studies of Wetland Filtration of Mine Waste Water in Constructed and Naturally Occurring Systems in Northern Australia ». Water Science and Technology 29, n^o 4 (1 février 1994) : 257–65. http://dx.doi.org/10.2166/wst.1994.0205.

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A problem common to mines operating in the tropics is the disposal of water, which may be alkaline, acidic, or contain toxic elements such as arsenic or cadmium. The availability of year-round water supply at many mine sites in Northern Australia, particularly from pit dewatering, together with the monsoonal climate, provide appropriate conditions for the formation of natural wetlands or establishment of artificial wetlands. Wetland species (particularly Typha spp.) flourish in the presence of flowing or shallow water from dewatering, and data collected from natural and experimental wetlands show reduction of metal concentrations by wetland filtration of mine waste water. The following case studies are considered:Constructed wetlands, used to remove uranium from waste rock runoff before release to an adjacent creek provide a means of “polishing” runoff water prior to discharge to the creek.Creek-Billabong systems with existing wetlands adjacent to mine sites adventitiously “filter” waters discharged from mine sites. Trace elements in dewatering water from a gold mine discharged into an oxbow show reduction of elemental concentrations downstream, compared to discharge water.Naturally generated wetlands at several Northern Territory mines have developed along channels for discharge of pit water, with ingress of Typha domingensis. Such wetlands, associated with dewatering, have been examined at four mines, some with acid mine drainage. Water quality measured after wetland treatments shows reductions in concentrations of various heavy metals and sulfate. Volunteer Typha domingensis grows and spreads in shallow flowing channels, providing an inherent “filtration” of the water.Natural swamplands are incorporated in the waste rock runoff management design of a new gold mine, to reduce potentially high arsenic levels in the waste water. Constructed and naturally occurring wetlands may be used in the treatment of most mine waste waters to achieve levels of constituents acceptable for discharge to the surrounding environment.

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Vymazal, Jan. « The Historical Development of Constructed Wetlands for Wastewater Treatment ». Land 11, n^o 2 (21 janvier 2022) : 174. http://dx.doi.org/10.3390/land11020174.

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Constructed wetlands (CWs) for wastewater treatment are engineered systems that are designed and operated in order to use all natural processes involved in the removal of pollutants from wastewaters. CWs are designed to take advantage of many of the same processes that occur in natural wetlands, but do so within a more controlled environment. The basic classification is based on the presence/absence of wastewater on the wetland surface. The subsurface flow of CWs can be classified according to the direction of the flow to horizontal and vertical. The combination of various types of CWs is called hybrid CW. The CWs technology began in the 1950s in Germany, but the major extension across the world occurred during the 1990s and early 2000s. The early CWs in Germany were designed as hybrid CWs; however, during the 1970s and 1980s, horizontal subsurface flow CWs were mostly designed. The stricter limits for nitrogen, and especially ammonia, applied in Europe during the 1990s, brought more attention to vertical subsurface flow and hybrid systems. Constructed wetlands have been used to treat various types of wastewater, including sewage, industrial and agricultural wastewaters, various drainage and runoff waters and landfill leachate. Recently, more attention has also been paid to constructed treatment wetlands as part of a circular economy in the urban environments: it is clear that CWs are a good fit for the new concept of sponge cities.

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Wang, Wenlong, Mingzhu Sun, Yi Li, Siqi Zhao, Zhenming Zhang et Xiaofeng Luan. « Multi-Level Comprehensive Assessment of Constructed Wetland Ecosystem Health : A Case Study of Cuihu Wetland in Beijing, China ». Sustainability 14, n^o 20 (18 octobre 2022) : 13439. http://dx.doi.org/10.3390/su142013439.

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Wetlands are one of the world’s three major ecosystems. They not only maintain regional ecological balance but also provide an important guarantee for human survival. Wetland ecosystem health assessment serves as the foundation for wetland protection, management, and restoration. In this study, the method for wetland ecosystem health assessment proposed by the United States Environmental Protection Agency (US EPA) was selected and improved to systematically evaluate the health status of the Cuihu wetlands’ ecosystem at three levels. The results revealed that the Cuihu wetlands’ landscape development intensity index was 1.55, the total landscape pattern value was 10 points, and the total score for rapid evaluation was 0.79. Levels I and II indicated that the Cuihu wetlands’ ecosystem was in a good near-natural state. Additionally, level III revealed that ecosystem health is higher in area B than in area A. The Cuihu wetlands were characterized by low species diversity and low distribution of benthic animals and aquatic plants. The comprehensive evaluation results revealed that the Cuihu wetlands’ ecosystem is in a good health. In the future, the health status of the wetland ecosystem should be monitored regularly, the cultivation and propagation of aquatic plants should be strengthened, and effective methods to improve water quality and reduce soil salinity should be used to achieve the best health status of the Cuihu wetlands.

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Saxena, Shalini. « PARAMETERS EVALUATION OF MUNICIPAL WASTE WATER AFTER TREATMENT USING SUB SURFACE FLOW CONSTRUCTED WETLAND IN EKANT PARK BHOPAL ». International Journal of Research -GRANTHAALAYAH 4, n^o 12 (31 décembre 2016) : 24–30. http://dx.doi.org/10.29121/granthaalayah.v4.i12.2016.2388.

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Land areas which are wet during part or all of the year are referred as wetlands. Constructed wetlands are manmade systems that mimic the functions of natural wetlands and applied for wastewater treatment. Aim of the present study is to investigate the feasibility of using a Tracheophyte, Phragmiteskarka in constructed wetland for treatment of wastewater in an public park. The daily inlet and outlet wastewater physico-chemical parameters were analysed during the period of two months. The parameters studied were pH, BOD, COD, DO, Total Suspended Solids, Total Dissolved Solids, Nitrogen and Phosphorus. The percentage removal of the parameters were analysed and studied until the percent removal rate gets stabilized. The study showed that the subsurface flow constructed wetlands are best alternative among modern treatments.

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Wang, Xiao Yun, et Ai Min Fu. « Study on Sediment Characteristics in Artificial Wetland and Natural Wetland ». Advanced Materials Research 599 (novembre 2012) : 748–52. http://dx.doi.org/10.4028/www.scientific.net/amr.599.748.

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This paper studied the sidemen characteristics of artificial wetland and natural wetland by cumulant, sedimentary organic matter, DOC and nitrate content. The results showed that the sediments in artificial wetlands upper layer were instable and uncompacted and often had trouble collecting for various factors .which was different from in natural wetland. Artificial wetland must pass through the months and years pass by. Time operation due to be texture, cation exchange capacity and clay changes, resulting in increasing content of organic substances. Natural wetland sediments of dissolved organic carbon in a constructed wetland system is high and the overall performance is relatively stable. But nitrate content was higher and less stable than the constructed wetland sediments.

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Cao, Qingqing, Haijie Zhang, Wen Ma, Renqing Wang et Jian Liu. « Composition Characteristics of Organic Matter and Bacterial Communities under the Alternanthera philoxeroide Invasion in Wetlands ». Applied Sciences 10, n^o 16 (12 août 2020) : 5571. http://dx.doi.org/10.3390/app10165571.

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The influence of Alternanthera philoxeroide (alligator weed) invasion on wetland organic matter (OM) accumulation and bacterial changes is rarely studied, but is possibly an important step for revealing the invasion mechanism. Thus, the distribution characteristics of light fraction organic carbon and nitrogen (LFOC and LFON), and heavy fractions organic carbon and nitrogen (HFOC and HFON) were analyzed. Sampling was done on two sediment depths (0–15 cm and 15–25 cm) of invaded and normal habitats of two natural wetlands and two constructed wetlands, and bacterial taxa and composition in surface sediments were also analyzed by high-throughput sequencing. In the surface sediments, the LFOC and LFON contents were significantly higher in the constructed wetlands (0.791 and 0.043 g·kg−1) than in the natural wetlands (0.500 and 0.022 g·kg−1), and the contents of the C and N fractions were also prominently higher in the invaded areas than in normal wetland habitats. The OM storage was relatively stable. Proteobacteria (55.94%), Bacteroidetes (5.74%), Acidobacteria (6.66%), and Chloroflexi (4.67%) were the dominant bacterial phyla in the wetlands. The abundance of Acidobacteria, Actinobacteria, and Gemmatimonadetes were significantly higher in the invaded areas than in the normal habitats. The relative high abundance-based coverage estimator (ACE) index in the constructed wetlands and invaded areas suggested the corresponding high bacterial diversity. The significant and positive relationship between Acidobacteria and organic nitrogen concentrations suggested their potential and positive interrelationships. This study demonstrated that the alligator weed invasion could significantly change the compositions of sediment organic matterand bacteria, thus further changing the nutrition cycle and wetland microhabitat.

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Affam, Augustine Chioma, Jacqueline Wong Yun Fei et Wong Chee Chung. « Peat Soil Ecosystem Restoration for Development of a Wetland- a review ». IOP Conference Series : Earth and Environmental Science 1135, n^o 1 (1 janvier 2023) : 012038. http://dx.doi.org/10.1088/1755-1315/1135/1/012038.

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Abstract Constructed wetlands are sustainable wastewater treatment technology and have been used to treat a variety of wastewaters for decades, including domestic and industrial wastewaters. They take advantage of many of the same processes that occur in natural wetlands but do so in a more controlled or engineered system. To date, surface flow and subsurface flow wetlands are the two main categories of constructed wetland applications. On the other hand, peat soil is the decomposed organic matter that have built up over thousands of years, with high moisture content. Peat soil management is imperative to maintain the mire ecosystem. The use of rhizosphere biodegradation, phyto-stabilization and phyto-accumulation have shown the possibility of improving water quality of wetland associated with peat soil. Thus, the aim of this work is to present a review in the role of constructed wetland system for peat soil management and the water quality as restoration measures of the peat soil ecosystem to promote its suitability for agricultural purpose.

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Langergraber, Guenter. « Are constructed treatment wetlands sustainable sanitation solutions ? » Water Science and Technology 67, n^o 10 (1 mai 2013) : 2133–40. http://dx.doi.org/10.2166/wst.2013.122.

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The main objective of sanitation systems is to protect and promote human health by providing a clean environment and breaking the cycle of disease. In order to be sustainable, a sanitation system has to be not only economically viable, socially acceptable and technically and institutionally appropriate, but it should also protect the environment and the natural resources. ‘Resources-oriented sanitation’ describes the approach in which human excreta and water from households are recognized as resource made available for reuse. Nowadays, ‘resources-oriented sanitation’ is understood in the same way as ‘ecological sanitation’. For resources-oriented sanitation systems to be truly sustainable they have to comply with the definition of sustainable sanitation as given by the Sustainable Sanitation Alliance (SuSanA, www.susana.org). Constructed treatment wetlands meet the basic criteria of sustainable sanitation systems by preventing diseases, protecting the environment, and being an affordable, acceptable, and simple technology. Additionally, constructed treatment wetlands produce treated wastewater of high quality, which is fostering reuse, which in turn makes them applicable in resources-oriented sanitation systems. The paper discusses the features that make constructed treatment wetlands a suitable solution in sustainable resources-oriented sanitation systems, the importance of system thinking for sustainability, as well as key factors for sustainable implementation of constructed wetland systems.

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Wu, C. Y., C. M. Kao, C. E. Lin, C. W. Chen et Y. C. Lai. « Using a constructed wetland for non-point source pollution control and river water quality purification : a case study in Taiwan ». Water Science and Technology 61, n^o 10 (1 mai 2010) : 2549–55. http://dx.doi.org/10.2166/wst.2010.175.

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The Kaoping River Rail Bridge Constructed Wetland, which was commissioned in 2004, is one of the largest constructed wetlands in Taiwan. This multi-function wetland has been designed for the purposes of non-point source (NPS) pollutant removal, wastewater treatment, wildlife habitat, recreation, and education. The major influents of this wetland came from the local drainage trench containing domestic, agricultural, and industrial wastewaters, and effluents from the wastewater treatment plant of a paper mill. Based on the quarterly investigation results from 2007 to 2009, more than 96% of total coliforms (TC), 48% of biochemical oxygen demand (BOD), and 40% of nutrients (e.g. total nitrogen, total phosphorus) were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for the public, and rehabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.

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Meng et Dong. « LUCC and Ecosystem Service Value Assessment for Wetlands : A Case Study in Nansi Lake, China ». Water 11, n^o 8 (31 juillet 2019) : 1597. http://dx.doi.org/10.3390/w11081597.

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Wetland is one of the most important ecosystems in the world. A healthy wetland ecosystem is important to the development of a regional and even global economy, and it is also beneficial to the human living conditions. In this paper, remote sensing (RS), landscape metrics were used to analyze the land use/land cover change (LUCC), landscape pattern change and the ecosystem services value (ESV) from 1987 to 2017 in Nansi Lake wetland of China. The results showed: 54.4% of the natural wetlands in Nansi Lake were replaced by constructed wetlands in the past 30 years, the ecosystem was degraded and the landscape structure was fragmented due to the severe drought in 2002 and the development of aquaculture and tourism in recent years. The ESV of Nansi Lake wetland fluctuated from 1987 to 2017, and the average annual ESV ($8134/hm2) was much lower than that of global and China’s wetlands, the LUCC driven by human production and economic development leads to the reduction of ESV, especially the rapid increase of constructed wetlands. Finally, the implications of wetland laws and policies, wetland monitoring, assessment and database construction, and wetland regional development strategies were discussed for wetland protection and management.

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Yeh, T. Y., et C. H. Wu. « Pollutant removal within hybrid constructed wetland systems in tropical regions ». Water Science and Technology 59, n^o 2 (1 janvier 2009) : 233–40. http://dx.doi.org/10.2166/wst.2009.846.

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Hybrid constructed wetlands have received tremendous interests for water quality enhancement due to insufficient sewage treatment and groundwater deterioration in Taiwan. The main objectives of this study were to investigate pollutant removal efficiencies and mechanisms within field-scale hybrid natural purification systems. The studied hybrid constructed wetland systems include an oxidation pond, two serial surface flow wetlands with a cascade in between, and a subsurface flow wetland receiving secondary treated dormitory sewage. The average SS, BOD and COD percent removal efficiency was 86.7, 86.5 and 57.8%, respectively. The ratio of BOD to COD decreased from 0.65 in the initial aerobic compartment to 0.21 in anoxic parts of the systems, indicating most biological degradable materials were decomposed in the aerobic oxidation pond and surface flow wetlands. Heavy metal removal percentages of copper and zinc were 72.9 and 68.3%, respectively. Sedimentation and plant uptake are the possible sinks for metals retention. Significant phosphorus removal was not achieved in this study. Total Kjeldahl nitrogen (TKN) and ammonium decreased from 4.08 to 1.43 and 3.74 to 1.21 mg/L, respectively, while nitrate nitrogen increased from 1.91 to 3.85 mg/L within the aerobic oxidation pond and surface flow wetlands. This result demonstrated nitrification occurring within aerobic compartments. The nitrate nitrogen continued to decrease from 3.85 to 1.43 mg/L within the anoxic subsurface wetlands mainly through denitrification transformation. Total nitrogen removal was from 7.61 to 3.61 mg/L, with the percentage removal of total nitrogen around 52.6%. The primary nitrogen removal and transformation mechanisms within the studied wetland systems were nitrification within aerobic followed by denitrificaiton within anaerobic systems. The emergent macrophytes enhance aeration through oxygen transferring that attributing the higher organic matter removal and nitrification rate. The hybrid wetland systems are viable options of pollutants transformation and removal in tropical countries, while tertiary wastewater systems are too costly or unable to operate. Effluent of purified systems can comply with local surface water criteria rendering for groundwater recharge.

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Pradhanang, Soni M., Thomas Boving et Ehren Meisinger. « Floating Wetlands System : A viable alternative for water pollutants remediation ». MATEC Web of Conferences 280 (2019) : 05001. http://dx.doi.org/10.1051/matecconf/201928005001.

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Constructed floating wetlands is viable alternative for the treatment of stormwater, combined stormwater-sewer overflow, sewage and water supply reservoirs, among others. The use of this technology also allows to enhance the habitat, and improve aesthetics to the treatment facility. In brief, the constructed floating wetlands island treatment mechanism is a combination of several components and physico-chemical processes that mimic natural bioremediation. Plant roots play a major role in treatment processes within constructed floating wetland island since the water passes directly through root system underneath the floating mat. Pathways for contaminant removal/retention in floating wetland island are: release of extracellular enzymes, development of biofilms, flocculation of suspended matter, and plant uptake. This study summarizes the findings of four monitoring studies and emphasizes on the field studies that monitored how pond contaminants responded to the floating wetlands through extensive review of existing literature.

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Duncan, Colin P., et Peter M. Groffman. « Comparing Microbial Parameters in Natural and Constructed Wetlands ». Journal of Environmental Quality 23, n^o 2 (mars 1994) : 298–305. http://dx.doi.org/10.2134/jeq1994.00472425002300020012x.

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Kochi, Leticia Y., Patricia L. Freitas, Leila T. Maranho, Philippe Juneau et Marcelo P. Gomes. « Aquatic Macrophytes in Constructed Wetlands : A Fight against Water Pollution ». Sustainability 12, n^o 21 (5 novembre 2020) : 9202. http://dx.doi.org/10.3390/su12219202.

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There is growing concern among health institutions worldwide to supply clean water to their populations, especially to more vulnerable communities. Although sewage treatment systems can remove most contaminants, they are not efficient at removing certain substances that can be detected in significant quantities even after standard treatments. Considering the necessity of perfecting techniques that can remove waterborne contaminants, constructed wetland systems have emerged as an effective bioremediation solution for degrading and removing contaminants. In spite of their environmentally friendly appearance and efficiency in treating residual waters, one of the limiting factors to structure efficient artificial wetlands is the choice of plant species that can both tolerate and remove contaminants. For sometimes, the chosen plants composing a system were not shown to increase wetland performance and became a problem since the biomass produced must have appropriated destination. We provide here an overview of the use and role of aquatic macrophytes in constructed wetland systems. The ability of plants to remove metals, pharmaceutical products, pesticides, cyanotoxins and nanoparticles in constructed wetlands were compared with the removal efficiency of non-planted systems, aiming to evaluate the capacity of plants to increase the removal efficiency of the systems. Moreover, this review also focuses on the management and destination of the biomass produced through natural processes of water filtration. The use of macrophytes in constructed wetlands represents a promising technology, mainly due to their efficiency of removal and the cost advantages of their implantation. However, the choice of plant species composing constructed wetlands should not be only based on the plant removal capacity since the introduction of invasive species can become an ecological problem.

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Sandoval, Luis, Sergio Zamora-Castro, Monserrat Vidal-Álvarez et José Marín-Muñiz. « Role of Wetland Plants and Use of Ornamental Flowering Plants in Constructed Wetlands for Wastewater Treatment : A Review ». Applied Sciences 9, n^o 4 (17 février 2019) : 685. http://dx.doi.org/10.3390/app9040685.

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The vegetation in constructed wetlands (CWs) plays an important role in wastewater treatment. Popularly, the common emergent plants in CWs have been vegetation of natural wetlands. However, there are ornamental flowering plants that have some physiological characteristics similar to the plants of natural wetlands that can stimulate the removal of pollutants in wastewater treatments; such importance in CWs is described here. A literature survey of 87 CWs from 21 countries showed that the four most commonly used flowering ornamental vegetation genera were Canna, Iris, Heliconia and Zantedeschia. In terms of geographical location, Canna spp. is commonly found in Asia, Zantedeschia spp. is frequent in Mexico (a country in North America), Iris is most commonly used in Asia, Europe and North America, and species of the Heliconia genus are commonly used in Asia and parts of the Americas (Mexico, Central and South America). This review also compares the use of ornamental plants versus natural wetland plants and systems without plants for removing pollutants (organic matter, nitrogen, nitrogen and phosphorous compounds). The removal efficiency was similar between flowering ornamental and natural wetland plants. However, pollutant removal was better when using ornamental plants than in unplanted CWs. The use of ornamental flowering plants in CWs is an excellent option, and efforts should be made to increase the adoption of these system types and use them in domiciliary, rural and urban areas.

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Sun, Qiong, Xiaofang Wang et Li Wang. « Ecological impact of watershed water pollution control on coastal tourist scenic spots ». International Journal of Low-Carbon Technologies 15, n^o 1 (28 novembre 2019) : 84–88. http://dx.doi.org/10.1093/ijlct/ctz060.

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Abstract In recent years, the rapid development of coastal areas has polluted the watershed water, affecting the ecological environment of wetland scenic spots. This paper briefly introduced the constructed wetland, a means of watershed water pollution control, and briefly explained its mechanism of water pollution control. Then, an example of Yancheng Coastal Wetland Natural Reserve in Jiangsu Province was analyzed to analyze water quality ecological changes in the basin before and after the construction of constructed wetland. The results showed that the basin of the natural reserve changed from acidic to alkaline, and ammonia nitrogen, total nitrogen, total phosphorus and chemical oxygen demand decreased significantly and maintained at a relatively low level after the constructed wetland controlled the water pollution in the basin; subsurface constructed wetland had a better effect on reducing ammonia nitrogen, total nitrogen and total phosphorus; surface constructed wetland had a better effect on reducing chemical oxygen demand. In conclusion, constructed wetlands as a means of water pollution control in the watershed can effectively improve the water quality ecology of coastal wetland natural reserves.

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Lakatos, Gyula, Magdolna K. Kiss, Marianna Kiss et Péter Juhász. « Application of constructed wetlands for wastewater treatment in Hungary ». Water Science and Technology 35, n^o 5 (1 mars 1997) : 331–36. http://dx.doi.org/10.2166/wst.1997.0230.

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This paper presents a brief survey of the Hungarian constructed wetland types that have been established for wastewater treatment in the last thirty years, and gives an analysis of the design and performance of those reed ponds that have been constructed for the polishing of petrochemical wastewaters. Natural treatment processes are in great demand because they are protective of the environment and have low operation costs and satisfactory purification efficiency. Three major types of treatment wetlands are utilized in Hungary: free water surface system, subsurface flow system, and artificial floating meadow system. Since the 1970s, the petrochemical industry has utilized sewage treatment systems consisting of ponds of emergent and/or submerged macrophyte vegetation that operate as free water surface systems. In the wastewater treatment system of Nyirbogdány, the average COD removal efficiency is around 60%, while the reed-submerged weeds pond has an efficiency of 25%. In the reed pond of the TIFO post-treatment pond system, the total phosphorus removal averaged 40% for several years, while the nitrogen removal efficiency has not exceeded 35%. For both constructed wetlands, the nutrient stabilising and heavy metal accumulating role of the aquatic plant-periphyton complex has been quantified, and the biological water quality has been found to be typical of any other natural water bodies.

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Chakraborti, Rajat K., et James S. Bays. « Natural Treatment of High-Strength Reverse Osmosis Concentrate by Constructed Wetlands for Reclaimed Water Use ». Water 12, n^o 1 (4 janvier 2020) : 158. http://dx.doi.org/10.3390/w12010158.

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A pilot study using natural treatment methods such as a horizontal subsurface flow in constructed wetlands to treat the reverse osmosis concentrate (ROC) was conducted to manage nutrient and metals to reclaim the product water for the coastal wetlands and agriculture use. ROC had a significantly greater concentration of constituents than concentrations typically found in effluent of secondary treated wastewater. During the six-month wetland pilot study, the removal of nutrients from the ROC was monitored. Bulrush (Schoenoplectus californicus), a common wetland plant, tolerated high total dissolved solids (11,000–12,700 mg/L) and provided significant mass removal of nutrients in the concentrate (61% removal of nitrogen and 21% removal of phosphorus) under two hydraulic residence times (HRT1 = 2.5 days and HRT2 = 5 days). Concentration-based reductions of oxidized nitrogen, ammonia-nitrogen, orthophosphate were 63%, 23%, and 23% during HRT1 and 55%, 24%, and 11% during HRT2, respectively. Nutrient mass balance estimates of this microbially dominated wetland system and analysis of mass transformation pathways were also performed. Because of evaporative water loss, mass removal efficiencies were significant. Key processes included denitrification for nitrogen removal, possibly supplemented with Annamox reduction of NO3-N; labile carbon assimilation supporting oxidized nitrogen reduction; and phosphate-P uptake and precipitation within the gravel substrate. The results indicated that engineered wetland treatment offers useful benefits to the management of ROC produced from secondary treated effluent of wastewater through reduction in volume through evapotranspiration and reduction in concentration through biological transformations for beneficial reuse.

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Knight, Robert L. « Wildlife habitat and public use benefits of treatment wetlands ». Water Science and Technology 35, n^o 5 (1 mars 1997) : 35–43. http://dx.doi.org/10.2166/wst.1997.0159.

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Constructed and natural wetlands are being utilized for water quality management of a broad variety of wastewater types worldwide. While water treatment is a primary goal of many of these systems, there is a general recognition that ancillary benefits for public use and wildlife habitat are typical of some of these wetlands. Also, there are growing numbers of constructed wetlands that are primarily focused on providing habitat and/or public use while relying on pretreated wastewater as the principal water supply. Efforts are currently underway to document the normal ranges of human and wildlife use benefits of treatment wetlands, and to provide a reasoned assessment of the potential environmental risks associated with these systems. Information collected from existing surface-flow treatment wetlands indicates consistent net benefits for wildlife habitat and public use. An understanding of the relationship between design and operation of treatment wetlands, and their positive and negative ecological and societal responses, will allow for optimization of new wetland systems.

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Wu, C. Y., J. K. Liu, S. H. Cheng, D. E. Surampalli, C. W. Chen et C. M. Kao. « Constructed wetland for water quality improvement : a case study from Taiwan ». Water Science and Technology 62, n^o 10 (1 novembre 2010) : 2408–18. http://dx.doi.org/10.2166/wst.2010.492.

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In Taiwan, more than 20% of the major rivers are mildly to heavily polluted by domestic, industrial, and agricultural wastewaters due to the low percentage of sewers connected to wastewater treatment plants. Thus, constructed or engineered wetlands have been adopted as the major alternatives to clean up polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems for the wastewater polishment to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before it is discharged into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks for organics and metals. In this study, water and sediment samples were collected from the major wetland basins in KRRBCW. The investigation results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g. total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g. Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O2/m2 d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TN). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that a variation in microbial diversity in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of microbial ribospecies, which might contribute to the carbon degradation and nitrogen removal. Gradual disappearance of E. coli was also observed along the flow courses through natural attenuation mechanisms.

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Stott, R., E. May et D. D. Mara. « Parasite removal by natural wastewater treatment systems : performance of waste stabilisation ponds and constructed wetlands ». Water Science and Technology 48, n^o 2 (1 juillet 2003) : 97–104. http://dx.doi.org/10.2166/wst.2003.0095.

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Parasite removal and low cost systems for wastewater treatment have become increasingly important requirements in developed and developing countries to safeguard public health from wastewater-associated intestinal diseases. Pilot and field-scale ponds and wetlands in Brazil and Egypt have been investigated for the fate and removal of eggs of human intestinal parasites from domestic wastewater. In northeast Brazil, parasite removal was investigated for a series of five waste stabilisation ponds treating raw wastewater. In Egypt, parasite removal was studied for Gravel Bed Hydroponic constructed wetlands treating partially treated wastewater. Influents to ponds and wetlands contained a variety of parasite helminth eggs (e.g. Ascaris, hookworm, Trichuris, and Hymenolepis spp.). The ponds consistently removed parasite eggs though rate of removal by individual ponds may have been related to influent egg numbers and extent of short-circuiting. Parasite eggs were reduced on average by 94% and 99.9% in the anaerobic and facultative ponds respectively. No eggs were found in effluent from the second maturation pond. In the wetland system, parasite removal varied with reedbed length. The majority of parasite eggs were retained within the first 25 m. Parasite eggs were reduced on average by 98% after treatment in 50 m beds and completely removed after treatment in 100 m beds.

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Tian, Peng, Luodan Cao, Jialin Li, Ruiliang Pu, Yongchao Liu, Haitao Zhang et Caiyi Wang. « Ecosystem Stability Assessment of Yancheng Coastal Wetlands, a World Natural Heritage Site ». Land 11, n^o 4 (11 avril 2022) : 564. http://dx.doi.org/10.3390/land11040564.

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By evaluating the stability of coastal wetland ecosystems, health conditions of regional ecosystems can be revealed and the sustainable development of coastal wetlands can be promoted. Coastal wetlands have been scarcely involved in present ecosystem stability evaluation studies, these being performed with relatively simple evaluation data sources. Therefore, in this research, a comprehensive and representative ecosystem stability evaluation index system was constructed by using the pressure-state-response model and multi-source datasets from perspectives of internal and external environmental changes of the Yancheng coastal wetlands, Jiangsu, China. The analysis results indicated that: (1) The ecosystem stability of the Yancheng coastal wetlands was at an early warning stage, and all segments except the Binhai segment (relatively stable) were in an early warning state. (2) In the criterion layer, the Dafeng District and the whole Yancheng District were faced with the highest pressure, followed by the Dongtai, Xiangshui and Binhai segments, successively. The Sheyang segment reached the highest state level, followed by the Binhai, Xiangshui and Dafeng segments in succession. (3) In the factor layer, the whole Yancheng District was faced with high resource and socioeconomic double pressures, with a poor water quality state and relatively low environmental pressure; favorable soil, biological and landscape states; and positive response to wetland protection. Various factors varied from county to county. (4) In the index layer, the ecosystem stability of the Yancheng coastal wetlands was significantly influenced by the invasion of alien species, change rate of natural wetland area (D32), change rate of artificial wetland area, increment of aquafarm area, intensity of fertilizer application and coverage of dominant vegetations. The novel significance of this research lies in enriching global coastal wetlands ecosystem stability evaluation investigations by providing a typical case study.

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Ibekwe, A. Mark, Catherine M. Grieve et Stephen R. Lyon. « Characterization of Microbial Communities and Composition in Constructed Dairy Wetland Wastewater Effluent ». Applied and Environmental Microbiology 69, n^o 9 (septembre 2003) : 5060–69. http://dx.doi.org/10.1128/aem.69.9.5060-5069.2003.

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ABSTRACT Constructed wetlands have been recognized as a removal treatment option for high concentrations of contaminants in agricultural waste before land application. The goal of this study was to characterize microbial composition in two constructed wetlands designed to remove contaminants from dairy washwater. Water samples were collected weekly for 11 months from two wetlands to determine the efficiency of the treatment system in removal of chemical contaminants and total and fecal coliforms. The reduction by the treatment was greatest for biological oxygen demand, suspended solids, chemical oxygen demand, nitrate, and coliforms. There was only moderate removal of total nitrogen and phosphorus. Changes in the total bacterial community and ammonia-oxidizing bacterial composition were examined by using denaturing gradient gel electrophoresis (DGGE) and sequencing of PCR-amplified fragments of the gene carrying the α subunit of the ammonia monooxygenase gene (amoA) recovered from soil samples and DGGE bands. DGGE analysis of wetlands and manure samples revealed that the total bacterial community composition was dominated by bacteria from phylogenetic clusters related to Bacillus, Clostridium, Mycoplasma, Eubacterium, and Proteobacteria originally retrieved from the gastrointestinal tracts of mammals. The population of ammonia-oxidizing bacteria showed a higher percentage of Nitrosospira-like sequences from the wetland samples, while a higher percentage of Nitrosomonas-like sequences from manure, feces, raw washwater, and facultative pond was found. These results show that the wetland system is a natural process dependent upon the development of healthy microbial communities for optimal wastewater treatment.

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