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Sample records for plant constructed wetland

  1. Accumulation of Cd, Pb and Zn by 19 wetland plant species in constructed wetland.

    PubMed

    Liu, Jianguo; Dong, Yuan; Xu, Hai; Wang, Deke; Xu, Jiakuan

    2007-08-25

    Uptake and distribution of Cd, Pb and Zn by 19 wetland plant species were investigated with experiments in small-scale plot constructed wetlands, into which artificial wastewater dosed with Cd, Pb and Zn at concentrations of 0.5, 2.0 and 5.0mgl(-1) was irrigated. The results showed that the removal efficiency of Cd, Pb and Zn from the wastewater were more than 90%. Generally, there were tens differences among the 19 plant species in the concentrations and quantity accumulations of the heavy metals in aboveground part, underground part and whole plants. The distribution ratios into aboveground parts for the metals absorbed by plants varied also largely from about 30% to about 90%. All the plants accumulated, in one harvest, 19.85% of Cd, 22.55% of Pb and 23.75% of Zn that were added into the wastewater. Four plant species, e.g. Alternanthera philoxeroides, Zizania latifolia, Echinochloa crus-galli and Polygonum hydropiper, accumulated high amounts of Cd, Pb and Zn. Monochoria vaginalis was capable for accumulating Cd and Pb, Isachne globosa for Cd and Zn, and Digitaria sanguinalis and Fimbristylis miliacea for Zn. The results indicated that the plants, in constructed wetland for the treatment of wastewater polluted by heavy metals, can play important roles for removal of heavy metals through phytoextraction. Selection of plant species for use in constructed wetland will influence considerably removal efficiency and the function duration of the wetland. PMID:17353090

  2. Accumulation of Cd, Pb and Zn by 19 wetland plant species in constructed wetland.

    PubMed

    Liu, Jianguo; Dong, Yuan; Xu, Hai; Wang, Deke; Xu, Jiakuan

    2007-08-25

    Uptake and distribution of Cd, Pb and Zn by 19 wetland plant species were investigated with experiments in small-scale plot constructed wetlands, into which artificial wastewater dosed with Cd, Pb and Zn at concentrations of 0.5, 2.0 and 5.0mgl(-1) was irrigated. The results showed that the removal efficiency of Cd, Pb and Zn from the wastewater were more than 90%. Generally, there were tens differences among the 19 plant species in the concentrations and quantity accumulations of the heavy metals in aboveground part, underground part and whole plants. The distribution ratios into aboveground parts for the metals absorbed by plants varied also largely from about 30% to about 90%. All the plants accumulated, in one harvest, 19.85% of Cd, 22.55% of Pb and 23.75% of Zn that were added into the wastewater. Four plant species, e.g. Alternanthera philoxeroides, Zizania latifolia, Echinochloa crus-galli and Polygonum hydropiper, accumulated high amounts of Cd, Pb and Zn. Monochoria vaginalis was capable for accumulating Cd and Pb, Isachne globosa for Cd and Zn, and Digitaria sanguinalis and Fimbristylis miliacea for Zn. The results indicated that the plants, in constructed wetland for the treatment of wastewater polluted by heavy metals, can play important roles for removal of heavy metals through phytoextraction. Selection of plant species for use in constructed wetland will influence considerably removal efficiency and the function duration of the wetland.

  3. Examination of oxygen release from plants in constructed wetlands in different stages of wetland plant life cycle.

    PubMed

    Zhang, Jian; Wu, Haiming; Hu, Zhen; Liang, Shuang; Fan, Jinlin

    2014-01-01

    The quantification of oxygen release by plants in different stages of wetland plant life cycle was made in this study. Results obtained from 1 year measurement in subsurface wetland microcosms demonstrated that oxygen release from Phragmites australis varied from 108.89 to 404.44 mg O₂/m(2)/d during the different periods from budding to dormancy. Plant species, substrate types, and culture solutions had a significant effect on the capacity of oxygen release of wetland plants. Oxygen supply by wetland plants was estimated to potentially support a removal of 300.37 mg COD/m(2)/d or 55.87 mg NH₄-N/m(2)/d. According to oxygen balance analysis, oxygen release by plants could provide 0.43-1.12% of biochemical oxygen demand in typical subsurface-flow constructed wetlands (CWs). This demonstrates that oxygen release of plants may be a potential source for pollutants removal especially in low-loaded CWs. The results make it possible to quantify the role of plants in wastewater purification.

  4. [Construction of a landscaping-type wetland system for wastewater treatment construction of a landscaping-type wetland system for wastewater treatment and analysis of plant denitrifying effect].

    PubMed

    Chen, Ming-li; Wu, Xiao-fu; Chen, Yong-hua; Jiang, Li-juan; Ji, Zhi-hui; Ma, Qun

    2010-03-01

    A pilot landscaping-type wetland system for wastewater treatment was constructed by introduction of 15 selected ornamental plant species (including 4 terrestrial plant species). The pilot system consists of 2 sequenced treatment units and 12 sub-units, i.e., a primary treatment unit with 4 parallel cells and a secondary treatment unit with 8 subsurface flow cells. Designed experiments were conducted in the established system to investigate the characteristics of nitrogen accumulation in different plants and the contribution of plant nitrogen uptake to total nitrogen removal of the constructed wetland system. The result shows that the direct contribution by plant uptake to the total nitrogen removal is low, ca. 1%-3% within the nitrogen concentration range 37.5-55.6 mg/L in the influent. Plant uptake does not fully reflect the important role of the plant species in the constructed wetland system for wastewater treatment as the function of the plant should include further its interaction with microorganisms and wetland fillers by enhancing microbial activities and filler adsorption capacities. The plant denitrifying effect, defined as the difference in nitrogen removal rates between units with and without plants, has been used to represent the contribution in nitrogen removal due to presence of plant in the system. The plant denitrifying effect thus includes both the plant nitrogen uptake and the interaction effect of plant with microorganisms and wetland fillers, the later being found to account for more than 80% of the total nitrogen removal in the established treatment system.

  5. Nitrogen and COD Removal from Septic Tank Wastewater in Subsurface Flow Constructed Wetlands: Plants Effects.

    PubMed

    Collison, R S; Grismer, M E

    2015-11-01

    We evaluated subsurface flow (SSF) constructed wetland treatment performance with respect to organics (COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) wastewater as affected by the presence of plants, substrate "rock" cation exchange capacity (CEC), laboratory versus field conditions and use of synthetic as compared to actual domestic wastewater. This article considers the effects of plants on constructed wetland treatment in the field. Each constructed wetland system was comprised of two beds (2.6 m long by 0.28 m wide and deep filled with ~18 mm crushed lava rock) separated by an aeration tank connected in series. The lava rock had a porosity of ~47% and a CEC of 4 meq/100 gm. One pair of constructed wetland systems was planted with cattails in May 2008, while an adjacent pair of systems remained un-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each constructed wetland system and effluent samples were regularly collected and tested for COD and nitrogen species during four time periods spanning November 2008 through June 2009. These effluent concentrations were tested for statistical differences at the 95% level for individual time periods as well as the overall 6-month period. Organics removal from domestic wastewater was 78.8% and 76.1% in the planted and un-planted constructed wetland systems, respectively, while ammonium removal was 94.5% and 90.2%, respectively. Similarly, organics removal from the synthetic wastewater of equivalent strength was 88.8% and 90.1% for planted and un-planted constructed wetland systems, respectively, while ammonium removal was 96.9% and 97.3%, respectively.

  6. Plant and Invertebrate Community Changes Caused by Flood-Pulsing in a Constructed Riparian Wetland

    NASA Astrophysics Data System (ADS)

    Caiazza, M. K.; Nieset, J. E.; Romito, A.; de Szalay, F. A.

    2005-05-01

    In 2002, Kent State University constructed a research facility that includes ten independently flooded wetland basins (10 m X 20 m) along a second order creek. We tested the effects of flood-pulsing on the wetland biota by allowing 5 basins (flood-pulse wetlands) to fluctuate with creek water levels to simulate floodplain marshes, and maintaining 5 basins (static wetlands) at constant water levels. We sampled emergent plants and aquatic invertebrates in 2003 and 2004. Abiotic conditions were different between treatments. We collected 83 plant species, and flood pulsing had strong effects on plant communities. Mean species richness and plant cover were higher in static wetlands, and Sorensen's similarity indices between habitat types decreased over time. Plant biomass increased in all wetlands from 2003 to 2004, but mean biomass was not different between treatments. Many dominant plant species were affected by the flood pulsing treatment. Wetland invertebrate communities were diverse (47 taxa), but we detected few responses. Total abundance, species richness, and numbers of most dominant species were not different between treatments. These results indicate that flood-pulsing acted as a stressor on emergent plant communities, but did not strongly impact aquatic macroinvertebrates.

  7. Relationships between Spatial Metrics and Plant Diversity in Constructed Freshwater Wetlands.

    PubMed

    Brandt, Erika C; Petersen, John E; Grossman, Jake J; Allen, George A; Benzing, David H

    2015-01-01

    The diversity of plant species and their distribution in space are both thought to have important effects on the function of wetland ecosystems. However, knowledge of the relationships between plant species and spatial diversity remains incomplete. In this study, we investigated relationships between spatial pattern and plant species diversity over a five year period following the initial restoration of experimental wetland ecosystems. In 2003, six identical and hydrologically-isolated 0.18 ha wetland "cells" were constructed in former farmland in northeast Ohio. The systems were subjected to planting treatments that resulted in different levels of vascular plant species diversity among cells. Plant species diversity was assessed through annual inventories. Plant spatial pattern was assessed by digitizing low-altitude aerial photographs taken at the same time as the inventories. Diversity metrics derived from the inventories were significantly related to certain spatial metrics derived from the photographs, including cover type diversity and contagion. We found that wetlands with high cover type diversity harbor higher plant species diversity than wetlands with fewer types of patches. We also found significant relationships between plant species diversity and spatial patterning of patch types, but the direction of the effect differed depending on the diversity metric used. Links between diversity and spatial pattern observed in this study suggest that high-resolution aerial imagery may provide wetland scientists with a useful tool for assessing plant diversity. PMID:26296205

  8. Relationships between Spatial Metrics and Plant Diversity in Constructed Freshwater Wetlands

    PubMed Central

    Grossman, Jake J.; Allen, George A.; Benzing, David H.

    2015-01-01

    The diversity of plant species and their distribution in space are both thought to have important effects on the function of wetland ecosystems. However, knowledge of the relationships between plant species and spatial diversity remains incomplete. In this study, we investigated relationships between spatial pattern and plant species diversity over a five year period following the initial restoration of experimental wetland ecosystems. In 2003, six identical and hydrologically-isolated 0.18 ha wetland “cells” were constructed in former farmland in northeast Ohio. The systems were subjected to planting treatments that resulted in different levels of vascular plant species diversity among cells. Plant species diversity was assessed through annual inventories. Plant spatial pattern was assessed by digitizing low-altitude aerial photographs taken at the same time as the inventories. Diversity metrics derived from the inventories were significantly related to certain spatial metrics derived from the photographs, including cover type diversity and contagion. We found that wetlands with high cover type diversity harbor higher plant species diversity than wetlands with fewer types of patches. We also found significant relationships between plant species diversity and spatial patterning of patch types, but the direction of the effect differed depending on the diversity metric used. Links between diversity and spatial pattern observed in this study suggest that high-resolution aerial imagery may provide wetland scientists with a useful tool for assessing plant diversity. PMID:26296205

  9. Effects of acidification on metal accumulation by aquatic plants and invertebrates. 1. Constructed wetlands

    SciTech Connect

    Albers, P.H.; Camardese, M.B. . Patuxent Wildlife Research Center)

    1993-06-01

    Compared were concentrations of Al,Cd,Ca,Cu,Fe,Hg,Pb,Mg,Mn,Ni,P, and Zn in water, plants and aquatic insects of three acidified (pH [approximately] 5.0) and three nonacidified (pH [approximately] 6.5) constructed wetlands. Concentrations of Zn in water and bur-reed (Sparganium americanum) were higher in acidified wetlands than in nonacidified wetlands. Floating nonrooted plants contained mean concentrations of Fe, Mg, and Mn that were higher than recommended maximum levels for poultry feed. The mean concentrations of all metals in insects were below recommended maximum levels for poultry feed and below levels that cause toxic effects in wild birds. Smaller than expected increases of metal concentrations in the water of acidified wetlands were probably due to limited mobilization of metals from the sediments and insignificant changes in sedimentation of aqueous metals. Calcium was lower in acidified than in nonacidified wetland water, but the Ca content of insects and bur-reed was not lower. Low concentrations of Ca in aquatic insects from both groups of wetlands indicated that calcium-rich crustaceans and mollusks are probably important to female waterfowl and their young during the spring, when invertebrates make up the majority of the diet. Although toxic effects from metal ingestion seem to be unlikely consequences of wetland acidification, the adverse effect of low pH on the occurrence of crustaceans and mollusks could threatened egg production and development of young.

  10. Temperature, plants, and oxygen: how does season affect constructed wetland performance?

    PubMed

    Stein, Otto R; Hook, Paul B

    2005-01-01

    The influence of temperature and plant-mediated oxygen transfer continues to draw attention from researchers, practitioners and regulators interested in the use of constructed wetlands for wastewater treatment. Because the vast majority of research on constructed wetland performance has been conducted during periods of active plant growth, the true influence of temperature, season, and plant species selection on constructed wetlands performance has not yet been evaluated adequately. In this article, we briefly summarize changes in the understanding of these influences on wetland performance, and suggest that effects of temperature and oxygen transfer are not readily separable because both factors respond to seasonal cycles and because effects of one can offset the other. We further speculate that the net effect of seasonal variation in these factors is such that plant-mediated oxygen transfer affects water treatment most in winter. Results of controlled-environment experiments conducted at Montana State University support these perspectives. Different plant species' capacities to oxidize the root zone responded differently to seasonal cycles of growth and dormancy, and species' effects on wastewater treatment were most pronounced in winter.

  11. Temperature, plants, and oxygen: how does season affect constructed wetland performance?

    PubMed

    Stein, Otto R; Hook, Paul B

    2005-01-01

    The influence of temperature and plant-mediated oxygen transfer continues to draw attention from researchers, practitioners and regulators interested in the use of constructed wetlands for wastewater treatment. Because the vast majority of research on constructed wetland performance has been conducted during periods of active plant growth, the true influence of temperature, season, and plant species selection on constructed wetlands performance has not yet been evaluated adequately. In this article, we briefly summarize changes in the understanding of these influences on wetland performance, and suggest that effects of temperature and oxygen transfer are not readily separable because both factors respond to seasonal cycles and because effects of one can offset the other. We further speculate that the net effect of seasonal variation in these factors is such that plant-mediated oxygen transfer affects water treatment most in winter. Results of controlled-environment experiments conducted at Montana State University support these perspectives. Different plant species' capacities to oxidize the root zone responded differently to seasonal cycles of growth and dormancy, and species' effects on wastewater treatment were most pronounced in winter. PMID:15921285

  12. Effects of plant species on soil microbial processes and CH4 emission from constructed wetlands.

    PubMed

    Wang, Yanhua; Yang, Hao; Ye, Chun; Chen, Xia; Xie, Biao; Huang, Changchun; Zhang, Jixiang; Xu, Meina

    2013-03-01

    Methane (CH(4)) emission from constructed wetland has raised environmental concern. This study evaluated the influence of mono and polyculture constructed wetland and seasonal variation on CH(4) fluxes. Methane emission data showed large temporal variation ranging from 0 to 249.29 mg CH(4) m(-2) h(-1). Results indicated that the highest CH(4) flux was obtained in the polyculture system, planted with Phragmites australis, Zizania latifolia and Typha latifolia, reflecting polyculture system could stimulate CH(4) emission. FISH analysis showed the higher amount of methanotrophs in the profile of Z. latifolia in both mono and polyculture systems. The highest methanogens amount and relatively lower methanotrophs amount in the profile of polyculture system were obtained. The results support the characteristics of CH(4) fluxes. The polyculture constructed wetland has the higher potential of global warming. PMID:23291006

  13. Effects of plant root on hydraulic performance of clogging process in subsurface flow constructed wetland

    NASA Astrophysics Data System (ADS)

    Hua, Guofen; Zhao, Zhongwei; Zeng, Yitao

    2013-04-01

    Subsurface flow constructed wetlands (SFCWs) have proven to be an efficient ecological technology for the treatment of various kinds of wastewaters. The clogging issue is the main operational problem, which limits its wide application. Clogging is a complicated process with physical (such as physical filtration), biogeochemical and plant-related processes. It was generally stated that suspended solids accumulation and biofilm play dominant roles response for clogging. However, the role of plants in SFCWs clogging remains unclear and debatable. In this paper, the performance of plants in the whole clogging process was addressed based on the lab-experiments between planted and unplanted system by measuring effective porosity, coefficient of permeability of the substrate within different operation periods. Furthermore, flow pattern and transport properties of the clogging process in the planted and unplanted wetland systems were evaluated by hydraulic performance (e.g. mean residence time, short-circuiting, volumetric efficiency, number of continuously stirred tank reactors, hydraulic efficiency factor, etc.) with salt tracer experiments. Plants played different roles in different clogging stage. In the earlier clogging stage, there were no obvious different effects on clogging process between planted and unplanted system. The effective porosity and coefficient of permeability slightly decreased within the planted system, which indicated that plant root restricted the flow of water when the pore spaces were lager. In the middle and later clogging stage, especially, in the later stage, the effective porosity and the coefficient of permeability increased considerably in the plant root zone. Furthermore, the longer retention times and higher hydraulic efficiency factors were gained in the planted system compared to that of unplanted, which implied that growing roots might open the new pore spaces in the substrate. The results are expected to be useful in the design of

  14. Phytoremediation of explosives contaminated ground waters by plant enzyme systems in constructed wetlands

    SciTech Connect

    Jackson, R.P. Jr.

    1995-12-31

    A plant enzyme system has successfully degraded the explosives TNT, RDX, and HMX to environmentally acceptable products during laboratory studies. The process has been further studied in the field in batch systems. The field results have been consistent with the laboratory findings. An artificial wetlands will be constructed to remediate explosives contaminated ground water at an Army ammunition plant. An overview of the phytoremediation program will be presented.

  15. Analysis of chemical reaction kinetics of depredating organic pollutants from secondary effluent of wastewater treatment plant in constructed wetlands.

    PubMed

    Wang, Hao; Jiang, Dengling; Yang, Yong; Cao, Guoping

    2013-01-01

    Four subsurface constructed wetlands were built to treat the secondary effluent of a wastewater treatment plant in Tangshan, China. The chemical pollutant indexes of chemical oxygen demand (COD) were analyzed to evaluate the removal efficiency of organic pollutants from the secondary effluent of the wastewater treatment plant. In all cases, the subsurface constructed wetlands were efficient in treating organic pollutants. Under the same hydraulic loading condition, the horizontal flow wetlands exhibited better efficiency of COD removal than vertical flow wetlands: the removal rates in horizontal flow wetlands could be maintained at 68.4 ± 2.42% to 92.2 ± 1.61%, compared with 63.8 ± 1.19% to 85.0 ± 1.25% in the vertical flow wetlands. Meanwhile, the chemical reaction kinetics of organic pollutants was analyzed, and the results showed that the degradation courses of the four subsurface wetlands all corresponded with the first order reaction kinetics to a large extent.

  16. Constructing wetlands: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

    NASA Astrophysics Data System (ADS)

    Saaltink, Rémon; Dekker, Stefan C.; Griffioen, Jasper; Wassen, Martin J.

    2016-04-01

    Interest is growing in using soft sediment as a building material in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here the option of dredging some of the clay-rich lake-bed sediment and using it to construct 10.000 ha of wetland will soon go under construction. Natural processes will be utilized during and after construction to accelerate ecosystem development. Knowing that plants can eco-engineer their environment via positive or negative biogeochemical plant-soil feedbacks, we conducted a six-month greenhouse experiment to identify the key biogeochemical processes in the mud when Phragmites australis is used as an eco-engineering species. We applied inverse biogeochemical modeling to link observed changes in pore water composition to biogeochemical processes. Two months after transplantation we observed reduced plant growth and shriveling as well as yellowing of foliage. The N:P ratios of plant tissue were low and were affected not by hampered uptake of N but by enhanced uptake of P. Plant analyses revealed high Fe concentrations in the leaves and roots. Sulfate concentrations rose drastically in our experiment due to pyrite oxidation; as reduction of sulfate will decouple Fe-P in reducing conditions, we argue that plant-induced iron toxicity hampered plant growth, forming a negative feedback loop, while simultaneously there was a positive feedback loop, as iron toxicity promotes P mobilization as a result of reduced conditions through root death, thereby stimulating plant growth and regeneration. Given these two feedback mechanisms, we propose that when building wetlands from these mud deposits Fe-tolerant species are used rather than species that thrive in N-limited conditions. The results presented in this study demonstrate the importance of studying the biogeochemical properties of the building material and the feedback mechanisms between plant and soil prior to finalizing the design of the eco-engineering project.

  17. Effects of acidification on metal accumulation by aquatic plants and invertebrates. 1. Constructed wetlands

    USGS Publications Warehouse

    Albers, P.H.; Camardese, M.B.

    1993-01-01

    The pH of lake water is often inversely correlated with concentrations of trace metals in the water column. Concentrations of Al, Cd, Ca, Cu, Fe, Hg, Pb, Mg, Mn, Ni, P, and Zn were compared in water, plants, and aquatic insects from three acidified (pH 5.0) and three nonacidified (pH 6.5) constructed wetlands. Concentrations of Zn in water and bur-reed (Sparganium americanum) were higher in acidified wetlands than in nonacidified wetlands. Floating nonrooted plants contained mean concentrations of Fe, Mg, and Mn that were higher than recommended maximum levels for poultry feed. The mean concentrations of all metals in insects were below recommended maximum levels for poultry feed and below levels that cause toxic effects in wild birds. Smaller than expected increases of metal concentrations in the water of acidified wetlands were probably due to limited mobilization of metals from the sediments and insignificant changes in sedimentation of aqueous metals. Calcium was lower in acidified than in nonacidified wetland water, but the Ca content of insects and bur-reed was not lower. Low concentrations of Ca in aquatic insects from both groups of wetlands indicate that calcium-rich crustaceans and mollusks are probably important to female waterfowl and their young during the spring, when invertebrates make up the majority of the diet. Although toxic effects from metal ingestion seem to be unlikely consequences of wetland acidification, the adverse effect of low pH on the occurrence of crustaceans and mollusks could threaten egg production and development of young.

  18. [Water treatment efficiency of constructed wetland plant-bed/ditch systems].

    PubMed

    Wang, Zhong-Qiong; Zhang, Rong-Bin; Chen, Qing-Hua; Wei, Hong-Bin; Wang, Wei-Dong

    2012-11-01

    Shijiuyang constructed wetland (SJY-CW) in Jiaxing City adopted plant-bed/ditch systems originated from the natural landscape as its major functioning unit. The constructed root channel technology (CRCT) is the core technique applied within the plant-bed/ditch systems. Monitoring results demonstrated that the wetland had the capability of improving water quality indexes by one rank grade according to the national environmental quality standards for surface water (GB 3838-2002). In order to optimize the water quality improvement function of plant-bed/ditch systems and CRCT, a pilot project in SJY-CW was constructed from May to October, 2010. The project contained 16 independent experimental cells. Orthogonal test design was applied to probe into the effects of constructed root channel layers, plant species combination, and reinforced physical substrates on promoting the water quality amelioration efficiency of the plant-bed/ditch systems. Comprehensively considering water treatment effects, construction difficulty, and construction and maintenance cost, the recommended optimal ways are as follows. Plant straws were preferably paved under subsurface zones by two layers with a gap of 20-30 cm. The preferable plant combination was reed (Phragmites australis) plus wild rice (Zizania caduciflora). Calcite might be applied as alternative reinforced media in some suitable sites of plant-bed/ditch systems. Water treatment effects were compared between pilot project and the whole wetland area of SJY-CW. The results showed that the reinforced pilot project exhibited higher treatment efficiency for nutrients than SJY-CW itself. The removal rates of total nitrogen, total phosphorus, and ammonia nitrogen were increased by about 20% - 40% in the pilot project. This suggested that SJY-CW could release its vast water treatment potential by means of increasing water flux through the subsurface root channel zones of plant beds. Therefore, some adjustment and control measures could be

  19. Decreases in ammonia volatilization in response to greater plant diversity in microcosms of constructed wetlands

    NASA Astrophysics Data System (ADS)

    Luo, Bin; Ge, Ying; Han, Wenjuan; Fan, Xing; Ren, Yuan; Du, Yuanyuan; Shi, Mengmeng; Chang, Jie

    2016-10-01

    Ammonia volatilization from wastewaters with a high concentration of ammonium is a serious environmental and health problem. Constructed wetlands (CWs) are widely used for treating wastewater, and plant diversity clearly improves some functions of ecosystem such as nitrogen removal. However, whether plant diversity can affect ammonia volatilization from wastewater is still unknown. In this study, we conducted a microcosm experiment with different plant diversity treatments using four plant species. Results showed that, (1) ammonia volatilization decreased with increasing plant species richness; (2) ammonia volatilization from systems containing Rumex japonicus was lower than other systems; and (3) ammonia volatilization was affected more by species composition than species richness. This paper is the first to report that ammonia volatilization is reduced by plant diversity, and that some plant species combinations are important to reduce ammonia volatilization from CWs when treating wastewater.

  20. Greenhouse gas production and efficiency of planted and artificially aerated constructed wetlands.

    PubMed

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-03-01

    Greenhouse gas (GHG) emissions by constructed wetlands (CWs) could mitigate the environmental benefits of nutrient removal in these man-made ecosystems. We studied the effect of 3 different macrophyte species and artificial aeration on the rates of nitrous oxide (N(2)O), carbon dioxide (CO(2)) and methane (CH(4)) production in CW mesocosms over three seasons. CW emitted 2-10 times more GHG than natural wetlands. Overall, CH(4) was the most important GHG emitted in unplanted treatments. Oxygen availability through artificial aeration reduced CH(4) fluxes. Plant presence also decreased CH(4) fluxes but favoured CO(2) production. Nitrous oxide had a minor contribution to global warming potential (GWP<15%). The introduction of oxygen through artificial aeration combined with plant presence, particularly Typha angustifolia, had the overall best performance among the treatments tested in this study, including lowest GWP, greatest nutrient removal, and best hydraulic properties.

  1. Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass.

    PubMed

    Kantawanichkul, Suwasa; Sattayapanich, Somsiri; van Dien, Frank

    2013-01-01

    The aim of this study was to investigate the efficiency of wastewater treatment by vertical flow constructed wetland systems under different hydraulic loading rates (HLR). The comparison of two types of plants, Cyperus alternifolius (Umbrella sedge) and Vetiveria zizanioides (Vetiver grass), was also conducted. In this study, six circular concrete tanks (diameter 0.8 m) were filled with fine sand and gravel to the depth of 1.23 m. Three tanks were planted with Umbrella sedge and the other three tanks were planted with Vetiver grass. Settled domestic wastewater from Chiang Mai University (chemical oxygen demand (COD), NH4(+)-N and suspended solids (SS) of 127.1, 27.4 and 29.5 mg/L on average, respectively) was intermittently applied for 45 min and rested for 3 h 15 min. The HLR of each tank was controlled at 20, 29 and 40 cm/d. It was found that the removal efficiency of the Umbrella sedge systems was higher than the Vetiver grass systems for every parameter, and the lowest HLR provided the maximum treatment efficiency. The removal efficiency of COD and nitrogen in terms of total Kjeldahl nitrogen (TKN) was 76 and 65% at 20 cm/d HLR for Umbrella sedge compared to only 67 and 56% for Vetiver grass. Nitrogen accumulation in plant biomass was also higher in Umbrella sedge than in Vetiver grass in every HLR. Umbrella sedge was thus proved to be a suitable constructed wetland plant in tropical climates.

  2. Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass.

    PubMed

    Kantawanichkul, Suwasa; Sattayapanich, Somsiri; van Dien, Frank

    2013-01-01

    The aim of this study was to investigate the efficiency of wastewater treatment by vertical flow constructed wetland systems under different hydraulic loading rates (HLR). The comparison of two types of plants, Cyperus alternifolius (Umbrella sedge) and Vetiveria zizanioides (Vetiver grass), was also conducted. In this study, six circular concrete tanks (diameter 0.8 m) were filled with fine sand and gravel to the depth of 1.23 m. Three tanks were planted with Umbrella sedge and the other three tanks were planted with Vetiver grass. Settled domestic wastewater from Chiang Mai University (chemical oxygen demand (COD), NH4(+)-N and suspended solids (SS) of 127.1, 27.4 and 29.5 mg/L on average, respectively) was intermittently applied for 45 min and rested for 3 h 15 min. The HLR of each tank was controlled at 20, 29 and 40 cm/d. It was found that the removal efficiency of the Umbrella sedge systems was higher than the Vetiver grass systems for every parameter, and the lowest HLR provided the maximum treatment efficiency. The removal efficiency of COD and nitrogen in terms of total Kjeldahl nitrogen (TKN) was 76 and 65% at 20 cm/d HLR for Umbrella sedge compared to only 67 and 56% for Vetiver grass. Nitrogen accumulation in plant biomass was also higher in Umbrella sedge than in Vetiver grass in every HLR. Umbrella sedge was thus proved to be a suitable constructed wetland plant in tropical climates. PMID:24056433

  3. Evapotranspiration from pilot-scale constructed wetlands planted with Phragmites australis in a Mediterranean environment.

    PubMed

    Milani, Mirco; Toscano, Attilio

    2013-01-01

    This article reports the results of evapotranspiration (ET) experiments carried out in Southern Italy (Sicily) in a pilot-scale constructed wetland (CW) made of a combination of vegetated (Phragmites australis) and unvegetated sub-surface flow beds. Domestic wastewater from a conventional wastewater treatment plant was used to fill the beds. Microclimate data was gathered from an automatic weather station close to the experimental plant. From June to November 2009 and from April to November 2010, ET values were measured as the amount of water needed to restore the initial volume in the beds after a certain period. Cumulative reference evapotranspiration (ET(0)) was similar to the cumulative ET measured in the beds without vegetation (ET(con)), while the Phragmites ET (ET (phr) ) was significantly higher underlining the effect of the vegetation. The plant coefficient of P. australis (K(p)) was very high (up to 8.5 in August 2009) compared to the typical K(c) for agricultural crops suggesting that the wetland environment was subjected to strong "clothesline" and "oasis" effects. According to the FAO 56 approach, K(p) shows different patterns and values in relation to growth stages correlating significantly to stem density, plant height and total leaves. The mean Water Use Efficiency (WUE) value of P. australis was quite low, about 2.27 g L(-1), probably due to the unlimited water availability and the lack of the plant's physiological adaptations to water conservation. The results provide useful and valid information for estimating ET rates in small-scale constructed wetlands since ET is a relevant issue in arid and semiarid regions. In these areas CW feasibility for wastewater treatment and reuse should also be carefully evaluated for macrophytes in relation to their WUE values.

  4. Seasonal nutrient uptake of plant biomass in a constructed wetland treating piggery wastewater effluent.

    PubMed

    Lee, S Y; Maniquiz, M C; Choi, J Y; Jeong, S M; Kim, L H

    2013-01-01

    The surface-flow constructed wetland (CW) located in Nonsan City, South Korea, and constructed as the final stage of a piggery wastewater treatment plant that aims to treat high nutrient content effluent during dry days and stormwater runoff during wet days was monitored from October 2008 to November 2011. This research investigated the seasonal nutrient uptake of plant biomass in the CW and nutrient concentration changes in each treatment region under monsoon and temperate climate conditions. Results showed that the mean total nitrogen removal during summer (June to August) was higher by 13% than in spring (March to May), while total phosphorus removal was higher by 22% in fall (September to November) than in winter (December to February). All plants in the CW reached their maximum biomass coverage and weight in summer and minimum growth in winter. The highest N and P content in plants occurred in September with 583.2 g/m(2) and August with 62.0 g/m(2), respectively. Based on the results, it is recommended that the harvesting of plants should be conducted during the time of the peak nutrient uptake and before the plants release the nutrient content back to the CW. The dependence of nutrient removal efficiency on plants is not so significant. In order to increase the nutrient removal rate by plant uptake, it is suggested that the treatment regions in the CW be covered by plants.

  5. Evaluation of the biotic potential of microorganisms and higher plants to enhance the quality of constructed wetlands. Final report

    SciTech Connect

    Mays, D.A.; Floyd, M.; Taylor, R.W.; Sistani, K.

    1998-09-30

    A project was carried out from October 1, 1991 through September 30, 1998 to evaluate the growth of several species of wetland plants in constructed cells using mine spoil as a growth medium, to evaluate microbial diversity and finally, to demonstrate the concept on an actual strip-mined site. In order to gain background information for evaluation of constructed wetlands, several wetlands on both undisturbed and strip-mined areas were evaluated to determine the physical and chemical characteristics of the substrates as well as the vegetation characteristics. The research phase of this projects consisted of 10 wetland cells each 7x16 m in size with the water depth varying from 0 to 40 cm. The substrates were allowed to stabilize over winter and each cell was planted in the spring of 1993 with 18 plants each of cattail, maidencance, soft stem bulrush and pickerel weed. All cells were thickly vegetated by the end of the first growing season.

  6. Loss of Plant Biodiversity Over a Seven-Year Period in Two Constructed Wetlands in Central New York

    NASA Astrophysics Data System (ADS)

    Kearney, Miranda A.; Fickbohm, Scott; Zhu, Weixing

    2013-05-01

    Since wetland construction projects are becoming more commonplace, meaningful follow-up studies are needed to evaluate how these systems change over time. To that end, the objective of our study was to examine the temporal changes in plant community composition and water chemistry in two constructed wetlands. We investigated two wetland sites that were constructed in 2003 in northern Otsego County, NY, a county that is largely dominated by agriculture. Site 1 was previously an active cow pasture and site 2 was previously a wet meadow surrounded by agricultural fields. No active plant introduction was made during the construction; however, both sites were located in areas with many remnant wetlands and were connected to through-flowing streams. In 2004 (Year 1) and 2010 (Year 7), the plant community composition and nitrogen retention were assessed. We found that both sites experienced site-wide declines in plant species richness, including the loss of upland and facultative upland species and the unanticipated loss of facultative wetland and some obligate species. We propose that high water levels, which, at their maximum depth were >1.5 m deeper than in Year 1, maintained by landowners in the years after the initial survey, may have been responsible for the unexpected loss of wetland species. We also found that site 1 exhibited considerable nitrogen retention in both Year 1 and Year 7; however, N concentrations were low at site 2 in both years.

  7. Loss of plant biodiversity over a seven-year period in two constructed wetlands in Central New York.

    PubMed

    Kearney, Miranda A; Fickbohm, Scott; Zhu, Weixing

    2013-05-01

    Since wetland construction projects are becoming more commonplace, meaningful follow-up studies are needed to evaluate how these systems change over time. To that end, the objective of our study was to examine the temporal changes in plant community composition and water chemistry in two constructed wetlands. We investigated two wetland sites that were constructed in 2003 in northern Otsego County, NY, a county that is largely dominated by agriculture. Site 1 was previously an active cow pasture and site 2 was previously a wet meadow surrounded by agricultural fields. No active plant introduction was made during the construction; however, both sites were located in areas with many remnant wetlands and were connected to through-flowing streams. In 2004 (Year 1) and 2010 (Year 7), the plant community composition and nitrogen retention were assessed. We found that both sites experienced site-wide declines in plant species richness, including the loss of upland and facultative upland species and the unanticipated loss of facultative wetland and some obligate species. We propose that high water levels, which, at their maximum depth were >1.5 m deeper than in Year 1, maintained by landowners in the years after the initial survey, may have been responsible for the unexpected loss of wetland species. We also found that site 1 exhibited considerable nitrogen retention in both Year 1 and Year 7; however, N concentrations were low at site 2 in both years.

  8. Purification of fuel and nitrate contaminated ground water using a free water surface constructed wetland plant

    SciTech Connect

    Machate, T.; Heuermann, E.; Schramm, K.W.; Kettrup, A.

    1999-10-01

    Contaminated ground water from a former coke plant site was purified in a free water surface (FWS) constructed wetland plant during a 3-mo short-term experiment. The pilot plant (total surface area 27 m{sup 2}) was filled with a 1 m thick lava-gravel substrate planted with cattail (Typha spp.) and bulrush (Scirpus lacustrls). Major contaminants were low to moderate concentrations of polycyclic aromatic hydrocarbons, BTEX, nitrate, and nitrite. The wetland was dosed at hydraulic loading rates of q{sub A} = 4.8 and 9.6 cm d{sup {minus}1} with a hydraulic residence time (HRT) of 13.7 and 6.8 d. The surface removal rates of PAH were between 98.8 and 1914 mg m{sup {minus}2} d{sup {minus}1}. Efficiency was always {gt}99%. Extraction of lava gravel showed that approx. 0.4% of the applied PAH were retained on the substratum. The ratio of {Sigma}2,3-ring PAH and {Sigma}4,5,6-ring PAH showed a shift from 1:0.11 in water to 1:2.5 in lava. The removal of BTEX was {gt}99%, but might be in part due to volatilization. The efficiency in the removal of nitrate was 91% and of nitrite was 97%. Purification performance was not influenced by hydraulic loading rates or after die-back of the macrophytes.

  9. Purification ability and carbon dioxide flux from surface flow constructed wetlands treating sewage treatment plant effluent.

    PubMed

    Wu, Haiming; Lin, Li; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Liu, Hai

    2016-11-01

    In this study, a two-year experiment was carried out to investigate variation of carbon dioxide (CO2) flux from free water surface constructed wetlands (FWS CW) systems treating sewage treatment plant effluent, and treatment performance was also evaluated. The better 74.6-76.6% COD, 92.7-94.4% NH4(+)-N, 60.1-84.7% TN and 49.3-70.7% TP removal efficiencies were achieved in planted CW systems compared with unplanted systems. The planted CW was a net CO2 sink, while the unplanted CW was a net CO2 source in the entire study period. An obvious annual and seasonal variability of CO2 fluxes from different wetland systems was also presented with the average CO2 flux ranging from -592.83mgm(-2)h(-1) to 553.91mgm(-2)h(-1) during 2012-2013. In addition, the net exchange of CO2 between CW systems and the atmosphere was significantly affected by air temperature, and the presence of plants also had the significant effect on total CO2 emissions.

  10. Purification ability and carbon dioxide flux from surface flow constructed wetlands treating sewage treatment plant effluent.

    PubMed

    Wu, Haiming; Lin, Li; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Liu, Hai

    2016-11-01

    In this study, a two-year experiment was carried out to investigate variation of carbon dioxide (CO2) flux from free water surface constructed wetlands (FWS CW) systems treating sewage treatment plant effluent, and treatment performance was also evaluated. The better 74.6-76.6% COD, 92.7-94.4% NH4(+)-N, 60.1-84.7% TN and 49.3-70.7% TP removal efficiencies were achieved in planted CW systems compared with unplanted systems. The planted CW was a net CO2 sink, while the unplanted CW was a net CO2 source in the entire study period. An obvious annual and seasonal variability of CO2 fluxes from different wetland systems was also presented with the average CO2 flux ranging from -592.83mgm(-2)h(-1) to 553.91mgm(-2)h(-1) during 2012-2013. In addition, the net exchange of CO2 between CW systems and the atmosphere was significantly affected by air temperature, and the presence of plants also had the significant effect on total CO2 emissions. PMID:27544264

  11. Nitrogen and phosphorus removal of locally adapted plant species used in constructed wetlands in China.

    PubMed

    Yu, Xia; König, Thomas; Qi, Zhang; Yongsheng, Gao

    2012-01-01

    This paper assesses the nitrogen and phosphorus removal efficiency of seven plant species (Schoenoplectus lacustris, Vetiveria zizanioides, Acorus calamus, Canna indica, Zizania latifolia, Phragmites communis, and Iris pseudacorus) commonly used in constructed wetland systems in southern China. The investigation considers two aspects that are relevant to determine nutrient removal efficiency: plants' biomass production and nutrient content in water effluent. Both assessments are correlated with each other. Three different hydraulic retention times with different nutrient loads have been applied in this ex-situ trial. The plants' biomass production correlates positively with the effluent's nutrient removal efficiency. Six out of seven species reviewed produce more biomass above ground than below ground (average: 67% of dried biomass in aerial part); only I. pseudacorus produces more biomass below ground. S. lacustris, V. zizanioides, I. pseudacorus, and C. indica have performed best in terms of nutrient removal efficiency (65.6-90.2% for nitrogen; 67.7-84.6% for phosphorus). PMID:22766855

  12. Nitrous oxide emission from polyculture constructed wetlands: effect of plant species.

    PubMed

    Wang, Yanhua; Inamori, Ryuhei; Kong, Hainan; Xu, Kaiqin; Inamori, Yuhei; Kondo, Takashi; Zhang, Jixiang

    2008-03-01

    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N2O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N2O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N2O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N2O m(-2) d(-1). The highest N2O emission occurred in the cell planted with Phragmites australis and Zizania latifolia. Whereas, the lower emission rate were obtained in the cell planted with P. australis and Typha latifolia. These revealed that Z. latifolia stimulated the N2O emission. Transportation of more organic matter and oxygen for AOB growth may be the reason. The study of AOB also supported this result, indicating that the root structure of Z. latifolia was favored by AOB for N2O formation.

  13. Nitrous oxide emission from polyculture constructed wetlands: effect of plant species.

    PubMed

    Wang, Yanhua; Inamori, Ryuhei; Kong, Hainan; Xu, Kaiqin; Inamori, Yuhei; Kondo, Takashi; Zhang, Jixiang

    2008-03-01

    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N2O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N2O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N2O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N2O m(-2) d(-1). The highest N2O emission occurred in the cell planted with Phragmites australis and Zizania latifolia. Whereas, the lower emission rate were obtained in the cell planted with P. australis and Typha latifolia. These revealed that Z. latifolia stimulated the N2O emission. Transportation of more organic matter and oxygen for AOB growth may be the reason. The study of AOB also supported this result, indicating that the root structure of Z. latifolia was favored by AOB for N2O formation. PMID:17655987

  14. Criteria for determining alternative plants to improve the resource recovery efficiency in constructed wetlands.

    PubMed

    Chiarawatchai, N; Heers, M; Otterpohl, R

    2008-01-01

    The aim of this study is to find the macrophytes that possess high resource recovery efficiency in subsurface-flow constructed wetlands (SFCWs) while not pose any negative effects to the treatment performance. Five criteria were included in this analysis. The suitable alternative plants were proposed according to their availabilities in each climate zone. For their potentials as an energy sources, they are related to plants' productivity as well as growth rate. Concerning the utilization options, plants that possess high economical value and/or versatilities were encouraged. Among the options are handicrafts, fertilizers, animal feeds, construction materials, paper making, and pharmaceutical products. In term of nutrient uptakes, in most cases they were relatively minor comparing to other removal mechanisms in SFCWs. No significant differences in term of treatment efficiency could be found. The proposed species have to be able to tolerate the municipal wastewater. The cost differences of plant propagules between each species are marginal, hence they should not be considered as the main selection criteria. Based on an investigation of 45 species worldwide, the recommendation table is developed with 13 suitable species that fit all the criteria. It appears that there are more than one "most appropriate plant species" in each climatic region. To perform the selection, the operators should weight their preferences on each criteria and the availability of plants in the area.

  15. Influences of plant type on bacterial and archaeal communities in constructed wetland treating polluted river water.

    PubMed

    Long, Yan; Yi, Hao; Chen, Sili; Zhang, Zhengke; Cui, Kai; Bing, Yongxin; Zhuo, Qiongfang; Li, Bingxin; Xie, Shuguang; Guo, Qingwei

    2016-10-01

    Both bacteria and archaeal communities can play important roles in biogeochemical processes in constructed wetland (CW) system. However, the influence of plant type on microbial community in surface water CW remains unclear. The present study investigated bacterial and archaeal communities in five surface water CW systems with different plant species. The abundance, richness, and diversity of both bacterial and archaeal communities considerably differed in these five CW systems. Compared with the other three CW systems, the CW systems planted with Vetiveria zizanioides or Juncus effusus L. showed much higher bacterial abundance but lower archaeal abundance. Bacteria outnumbered archaea in each CW system. Moreover, the CW systems planted with V. zizanioides or J. effusus L. had relatively lower archaeal but higher bacterial richness and diversity. In each CW system, bacterial community displayed much higher richness and diversity than archaeal community. In addition, a remarkable difference of both bacterial and archaeal community structures was observed in the five studied CW systems. Proteobacteria was the most abundant bacterial group (accounting for 33-60 %). Thaumarchaeota organisms (57 %) predominated in archaeal communities in CW systems planted with V. zizanioides or J. effusus L., while Woesearchaeota (23 or 24 %) and Euryarchaeota (23 or 15 %) were the major archaeal groups in CW systems planted with Cyperus papyrus or Canna indica L. Archaeal community in CW planted with Typha orientalis Presl was mainly composed of unclassified archaea. Therefore, plant type exerted a considerable influence on microbial community in surface water CW system. PMID:27392623

  16. Nitrogen transformations and retention in planted and artificially aerated constructed wetlands.

    PubMed

    Maltais-Landry, Gabriel; Maranger, Roxane; Brisson, Jacques; Chazarenc, Florent

    2009-02-01

    Nitrogen (N) processing in constructed wetlands (CWs) is often variable, and the contribution to N loss and retention by various pathways (nitrification/denitrification, plant uptake and sediment storage) remains unclear. We studied the seasonal variation of the effects of artificial aeration and three different macrophyte species (Phragmites australis, Typha angustifolia and Phalaris arundinacea) on N processing (removal rates, transformations and export) using experimental CW mesocosms. Removal of total nitrogen (TN) was higher in summer and in planted and aerated units, with the highest mean removal in units planted with T. angustifolia. Export of ammonium (NH(4)(+)), a proxy for nitrification limitation, was higher in winter, and in unplanted and non-aerated units. Planted and aerated units had the highest export of oxidized nitrogen (NO(y)), a proxy for reduced denitrification. Redox potential, evapotranspiration (ETP) rates and hydraulic retention times (HRT) were all predictors of TN, NH(4)(+) and NO(y) export, and significantly affected by plants. Denitrification was the main N sink in most treatments accounting for 47-62% of TN removal, while sediment storage was dominant in unplanted non-aerated units and units planted with P. arundinacea. Plant uptake accounted for less than 20% of the removal. Uncertainties about the long-term fate of the N stored in sediments suggest that the fraction attributed to denitrification losses could be underestimated in this study.

  17. Nitrogen removal performance in planted and unplanted horizontal subsurface flow constructed wetlands treating different influent COD/N ratios.

    PubMed

    Wang, Wei; Ding, Yi; Ullman, Jeffrey L; Ambrose, Richard F; Wang, Yuhui; Song, Xinshan; Zhao, Zhimiao

    2016-05-01

    Microcosm horizontal subsurface flow constructed wetlands (HSSFCWs) were used to examine the impacts of vegetation on nitrogen dynamics treating different influent COD/N ratios (1:1, 4:1, and 8:1). An increase in the COD/N ratio led to increased reductions in NO3 and total inorganic nitrogen (TIN) in planted and unplanted wetlands, but diminished removal of NH4. The HSSFCW planted with Canna indica L. exhibited a significant reduction in NH4 compared to the unplanted system, particularly in the active root zone where NH4 removal performance increased by up to 26 % at the COD/N ratio of 8:1. There was no significant difference in NO3 removal between the planted and unplanted wetlands. TIN removal efficiency in the planted wetland increased with COD/N ratios, which was likely influenced by plant uptake. NH4 reductions were greater in planted wetland at the 20- and 40-cm depths while NO3 reductions were uniformly greater with depth in all cases, but no statistical difference was impacted by depth on TIN removal. These findings show that planting a HSSFCW can provide some benefit in reducing nitrogen loads in effluents, but only when a sufficient carbon source is present.

  18. Wetland Water Cooling Partnership: The Use of Constructed Wetlands to Enhance Thermoelectric Power Plant Cooling and Mitigate the Demand of Surface Water Use

    SciTech Connect

    Apfelbaum, Steven; Duvall, Kenneth; Nelson, Theresa; Mensing, Douglas; Bengtson, Harlan; Eppich, John; Penhallegon, Clayton; Thompson, Ry

    2013-09-30

    Through the Phase I study segment of contract #DE-NT0006644 with the U.S. Department of Energy’s National Energy Technology Laboratory, Applied Ecological Services, Inc. and Sterling Energy Services, LLC (the AES/SES Team) explored the use of constructed wetlands to help address stresses on surface water and groundwater resources from thermoelectric power plant cooling and makeup water requirements. The project objectives were crafted to explore and develop implementable water conservation and cooling strategies using constructed wetlands (not existing, naturally occurring wetlands), with the goal of determining if this strategy has the potential to reduce surface water and groundwater withdrawals of thermoelectric power plants throughout the country. Our team’s exploratory work has documented what appears to be a significant and practical potential for augmenting power plant cooling water resources for makeup supply at many, but not all, thermoelectric power plant sites. The intent is to help alleviate stress on existing surface water and groundwater resources through harvesting, storing, polishing and beneficially re-using critical water resources. Through literature review, development of conceptual created wetland plans, and STELLA-based modeling, the AES/SES team has developed heat and water balances for conventional thermoelectric power plants to evaluate wetland size requirements, water use, and comparative cooling technology costs. The ecological literature on organism tolerances to heated waters was used to understand the range of ecological outcomes achievable in created wetlands. This study suggests that wetlands and water harvesting can provide a practical and cost-effective strategy to augment cooling waters for thermoelectric power plants in many geographic settings of the United States, particularly east of the 100th meridian, and in coastal and riverine locations. The study concluded that constructed wetlands can have significant positive

  19. A Hardy Plant Facilitates Nitrogen Removal via Microbial Communities in Subsurface Flow Constructed Wetlands in Winter.

    PubMed

    Wang, Penghe; Zhang, Hui; Zuo, Jie; Zhao, Dehua; Zou, Xiangxu; Zhu, Zhengjie; Jeelani, Nasreen; Leng, Xin; An, Shuqing

    2016-01-01

    The plants effect in subsurface flow constructed wetlands (SSF-CWs) is controversial, especially at low temperatures. Consequently, several SSF-CWs planted with Iris pseudacorus (CWI) or Typha orientalis Presl. (CWT) and several unplanted ones (CWC) were set up and fed with secondary effluent of sewage treatment plant during the winter in Eastern China. The 16S rDNA Illumina Miseq sequencing analysis indicated the positive effects of I. pseudacorus on the bacterial community richness and diversity in the substrate. Moreover, the community compositions of the bacteria involved with denitrification presented a significant difference in the three systems. Additionally, higher relative abundances of nitrifying bacteria (0.4140%, 0.2402% and 0.4318% for Nitrosomonas, Nitrosospira and Nitrospira, respectively) were recorded in CWI compared with CWT (0.2074%, 0.0648% and 0.0181%, respectively) and CWC (0.3013%, 0.1107% and 0.1185%, respectively). Meanwhile, the average removal rates of NH4(+)-N and TN in CWI showed a prominent advantage compared to CWC, but no distinct advantage was found in CWT. The hardy plant I. pseudacorus, which still had active root oxygen release in cold temperatures, positively affected the abundance of nitrifying bacteria in the substrate, and accordingly was supposed to contribute to a comparatively high nitrogen removal efficiency of the system during the winter. PMID:27646687

  20. A Hardy Plant Facilitates Nitrogen Removal via Microbial Communities in Subsurface Flow Constructed Wetlands in Winter

    PubMed Central

    Wang, Penghe; Zhang, Hui; Zuo, Jie; Zhao, Dehua; Zou, Xiangxu; Zhu, Zhengjie; Jeelani, Nasreen; Leng, Xin; An, Shuqing

    2016-01-01

    The plants effect in subsurface flow constructed wetlands (SSF-CWs) is controversial, especially at low temperatures. Consequently, several SSF-CWs planted with Iris pseudacorus (CWI) or Typha orientalis Presl. (CWT) and several unplanted ones (CWC) were set up and fed with secondary effluent of sewage treatment plant during the winter in Eastern China. The 16S rDNA Illumina Miseq sequencing analysis indicated the positive effects of I. pseudacorus on the bacterial community richness and diversity in the substrate. Moreover, the community compositions of the bacteria involved with denitrification presented a significant difference in the three systems. Additionally, higher relative abundances of nitrifying bacteria (0.4140%, 0.2402% and 0.4318% for Nitrosomonas, Nitrosospira and Nitrospira, respectively) were recorded in CWI compared with CWT (0.2074%, 0.0648% and 0.0181%, respectively) and CWC (0.3013%, 0.1107% and 0.1185%, respectively). Meanwhile, the average removal rates of NH4+-N and TN in CWI showed a prominent advantage compared to CWC, but no distinct advantage was found in CWT. The hardy plant I. pseudacorus, which still had active root oxygen release in cold temperatures, positively affected the abundance of nitrifying bacteria in the substrate, and accordingly was supposed to contribute to a comparatively high nitrogen removal efficiency of the system during the winter. PMID:27646687

  1. A Hardy Plant Facilitates Nitrogen Removal via Microbial Communities in Subsurface Flow Constructed Wetlands in Winter

    NASA Astrophysics Data System (ADS)

    Wang, Penghe; Zhang, Hui; Zuo, Jie; Zhao, Dehua; Zou, Xiangxu; Zhu, Zhengjie; Jeelani, Nasreen; Leng, Xin; An, Shuqing

    2016-09-01

    The plants effect in subsurface flow constructed wetlands (SSF-CWs) is controversial, especially at low temperatures. Consequently, several SSF-CWs planted with Iris pseudacorus (CWI) or Typha orientalis Presl. (CWT) and several unplanted ones (CWC) were set up and fed with secondary effluent of sewage treatment plant during the winter in Eastern China. The 16S rDNA Illumina Miseq sequencing analysis indicated the positive effects of I. pseudacorus on the bacterial community richness and diversity in the substrate. Moreover, the community compositions of the bacteria involved with denitrification presented a significant difference in the three systems. Additionally, higher relative abundances of nitrifying bacteria (0.4140%, 0.2402% and 0.4318% for Nitrosomonas, Nitrosospira and Nitrospira, respectively) were recorded in CWI compared with CWT (0.2074%, 0.0648% and 0.0181%, respectively) and CWC (0.3013%, 0.1107% and 0.1185%, respectively). Meanwhile, the average removal rates of NH4+-N and TN in CWI showed a prominent advantage compared to CWC, but no distinct advantage was found in CWT. The hardy plant I. pseudacorus, which still had active root oxygen release in cold temperatures, positively affected the abundance of nitrifying bacteria in the substrate, and accordingly was supposed to contribute to a comparatively high nitrogen removal efficiency of the system during the winter.

  2. A Hardy Plant Facilitates Nitrogen Removal via Microbial Communities in Subsurface Flow Constructed Wetlands in Winter.

    PubMed

    Wang, Penghe; Zhang, Hui; Zuo, Jie; Zhao, Dehua; Zou, Xiangxu; Zhu, Zhengjie; Jeelani, Nasreen; Leng, Xin; An, Shuqing

    2016-09-20

    The plants effect in subsurface flow constructed wetlands (SSF-CWs) is controversial, especially at low temperatures. Consequently, several SSF-CWs planted with Iris pseudacorus (CWI) or Typha orientalis Presl. (CWT) and several unplanted ones (CWC) were set up and fed with secondary effluent of sewage treatment plant during the winter in Eastern China. The 16S rDNA Illumina Miseq sequencing analysis indicated the positive effects of I. pseudacorus on the bacterial community richness and diversity in the substrate. Moreover, the community compositions of the bacteria involved with denitrification presented a significant difference in the three systems. Additionally, higher relative abundances of nitrifying bacteria (0.4140%, 0.2402% and 0.4318% for Nitrosomonas, Nitrosospira and Nitrospira, respectively) were recorded in CWI compared with CWT (0.2074%, 0.0648% and 0.0181%, respectively) and CWC (0.3013%, 0.1107% and 0.1185%, respectively). Meanwhile, the average removal rates of NH4(+)-N and TN in CWI showed a prominent advantage compared to CWC, but no distinct advantage was found in CWT. The hardy plant I. pseudacorus, which still had active root oxygen release in cold temperatures, positively affected the abundance of nitrifying bacteria in the substrate, and accordingly was supposed to contribute to a comparatively high nitrogen removal efficiency of the system during the winter.

  3. Microbial abundance and community in subsurface flow constructed wetland microcosms: role of plant presence.

    PubMed

    Wang, Qian; Xie, Huijun; Ngo, Huu Hao; Guo, Wenshan; Zhang, Jian; Liu, Cui; Liang, Shuang; Hu, Zhen; Yang, Zhongchen; Zhao, Congcong

    2016-03-01

    In this research, the role of plants in improving microorganism growth conditions in subsurface flow constructed wetland (CW) microcosms was determined. In particular, microbial abundance and community were investigated during summer and winter in Phragmites australis-planted CW microcosms (PA) and unplanted CW microcosms (control, CT). Results revealed that the removal efficiencies of pollutants and microbial community structure varied in winter with variable microbial abundance. During summer, PA comprised more dominant phyla (e.g., Proteobacteria, Actinobacteria, and Bacteroidetes), whereas CT contained more Cyanobacteria and photosynthetic bacteria. During winter, the abundance of Proteobacteria was >40 % in PA but dramatically decreased in CT. Moreover, Cyanobacteria and photosynthetic bacterial dominance in CT decreased. In both seasons, bacteria were more abundant in root surfaces than in sand. Plant presence positively affected microbial abundance and community. The potential removal ability of CT, in which Cyanobacteria and photosynthetic bacteria were abundant during summer, was more significantly affected by temperature reduction than that of PA with plant presence. PMID:25772872

  4. Effect of season, substrate composition, and plant growth on landfill leachate treatment in a constructed wetland

    SciTech Connect

    Surface, J.M. ); Peverly, J.H. . Dept. of Soil, Crops, and Atmospheric Sciences); Steenhuis, T.S. . Dept. of Agricultural and Biological Engineering); Sanford, W.E. )

    1991-01-01

    In 1989 the US, Geological Survey (USGS), in cooperation with Tompkins County, New York Departments of Planning and Solid Waste, began a 3-year study at a municipal solid-waste landfill near Ithaca, N.Y., to test the efficiency of leachate treatment by constructed wetlands and to examine the associated treatment processes. Specific objectives of the study were to examine: (1) Treatment efficiency as function of substrate composition and grain size, degree of plant growth, and seasonal changes in evapotranspiration rates and microbial activity; (2) effects of leachate and plant growth on the hydraulic characteristics of the substrate; and (3) chemical, biological, and physical processes by which nutrients, metals, and organic compounds are removed from leachate as it flows through the substrate. This report addresses the first two of these objectives and briefly discusses the third. It (1) describes the substrate plots, leachate-distribution system, sampling methods, and analytical procedures; and (2) presents results in terms of (a) percent removal rates of selected constituents between inflow- and outflow-sampling points, (b) seasonal effects on constituent-removal rates, and (c) effect of substrate composition on constituent removal and plant growth.

  5. Effect of season, substrate composition, and plant growth on landfill leachate treatment in a constructed wetland

    SciTech Connect

    Surface, J.M.; Peverly, J.H.; Steenhuis, T.S.; Sanford, W.E.

    1991-12-31

    In 1989 the US, Geological Survey (USGS), in cooperation with Tompkins County, New York Departments of Planning and Solid Waste, began a 3-year study at a municipal solid-waste landfill near Ithaca, N.Y., to test the efficiency of leachate treatment by constructed wetlands and to examine the associated treatment processes. Specific objectives of the study were to examine: (1) Treatment efficiency as function of substrate composition and grain size, degree of plant growth, and seasonal changes in evapotranspiration rates and microbial activity; (2) effects of leachate and plant growth on the hydraulic characteristics of the substrate; and (3) chemical, biological, and physical processes by which nutrients, metals, and organic compounds are removed from leachate as it flows through the substrate. This report addresses the first two of these objectives and briefly discusses the third. It (1) describes the substrate plots, leachate-distribution system, sampling methods, and analytical procedures; and (2) presents results in terms of (a) percent removal rates of selected constituents between inflow- and outflow-sampling points, (b) seasonal effects on constituent-removal rates, and (c) effect of substrate composition on constituent removal and plant growth.

  6. [Selection and purification potential evaluation of woody plant in vertical flow constructed wetlands in the subtropical area].

    PubMed

    Chen, Yong-Hua; Wu, Xiao-Fu; Hao, Jun; Chen, Ming-Li; Zhu, Guang-Yu

    2014-02-01

    In order to solve the problem that wetland herbaceous plants tend to die during winter in subtropics areas, selection and purification potential evaluation experiments were carried out by introducing into the constructed wetlands 16 species of woody wetland plants. Cluster analysis was performed by including the morphological characteristics, physiological characteristics, as well as nitrogen and phosphorus accumulation of the woody wetland plants. The results indicated that there were significant differences among the tested woody plants in their survival rate, height increase, root length increase and vigor, Chlorophyll content, Superoxide dismutase, Malonaldehyde, Proline, Peroxidase, biomass, average concentration and accumulation of nitrogen and phosphorus. Based on the established evaluation system, the tested plants were clustered into 3 groups. The plants in the 1st group possessing high purification potentials are Nerium oleander and Hibiscus syriacus. Those in the 2nd group possessing moderate purification potentials are Trachycarpus fortune, Llex latifolia Thunb., Gardenia jasminoides, Serissa foetida and Ilex crenatacv Convexa. And those in the 3rd group with low purification potentials are Jasminum udiflorum, Hedera helix, Ligustrum vicaryi, Ligustrum lucidum, Buxus sempervives, Murraya paniculata, Osmanthus fragrans, Mahoniafortune and Photinia serrulata. PMID:24812951

  7. Sulfate removal and sulfur transformation in constructed wetlands: The roles of filling material and plant biomass.

    PubMed

    Chen, Yi; Wen, Yue; Zhou, Qi; Huang, Jingang; Vymazal, Jan; Kuschk, Peter

    2016-10-01

    Sulfate in effluent is a challenging issue for wastewater reuse around the world. In this study, sulfur (S) removal and transformation in five batch constructed wetlands (CWs) treating secondary effluent were investigated. The results showed that the presence of the plant cattail (Typha latifolia) had little effect on sulfate removal, while the carbon-rich litter it generated greatly improved sulfate removal, but with limited sulfide accumulation in the pore-water. After sulfate removal, most of the S was deposited with the valence states S (-II) and S (0) on the iron-rich gravel surface, and acid volatile sulfide was the main S sink in the litter-added CWs. High-throughput pyrosequencing revealed that sulfate-reducing bacteria (i.e. Desulfobacter) and sulfide-oxidizing bacteria (i.e. Thiobacillus) were dominant in the litter-added CWs, which led to a sustainable S cycle between sulfate and sulfide. Overall, this study suggests that recycling plant litter and iron-rich filling material in CWs gives an opportunity to utilize the S in the wastewater as both an electron acceptor for sulfate reduction and as an electron donor for nitrate reduction coupled with sulfide oxidation. This leads to the simultaneous removal of sulfate, nitrate, and organics without discharging toxic sulfide into the receiving water body. PMID:27423407

  8. Sulfate removal and sulfur transformation in constructed wetlands: The roles of filling material and plant biomass.

    PubMed

    Chen, Yi; Wen, Yue; Zhou, Qi; Huang, Jingang; Vymazal, Jan; Kuschk, Peter

    2016-10-01

    Sulfate in effluent is a challenging issue for wastewater reuse around the world. In this study, sulfur (S) removal and transformation in five batch constructed wetlands (CWs) treating secondary effluent were investigated. The results showed that the presence of the plant cattail (Typha latifolia) had little effect on sulfate removal, while the carbon-rich litter it generated greatly improved sulfate removal, but with limited sulfide accumulation in the pore-water. After sulfate removal, most of the S was deposited with the valence states S (-II) and S (0) on the iron-rich gravel surface, and acid volatile sulfide was the main S sink in the litter-added CWs. High-throughput pyrosequencing revealed that sulfate-reducing bacteria (i.e. Desulfobacter) and sulfide-oxidizing bacteria (i.e. Thiobacillus) were dominant in the litter-added CWs, which led to a sustainable S cycle between sulfate and sulfide. Overall, this study suggests that recycling plant litter and iron-rich filling material in CWs gives an opportunity to utilize the S in the wastewater as both an electron acceptor for sulfate reduction and as an electron donor for nitrate reduction coupled with sulfide oxidation. This leads to the simultaneous removal of sulfate, nitrate, and organics without discharging toxic sulfide into the receiving water body.

  9. Removal mechanisms and plant species selection by bioaccumulative factors in surface flow constructed wetlands (CWs): In the case of triclosan.

    PubMed

    Zhao, Congcong; Xie, HuiJun; Xu, Jingtao; Zhang, Jian; Liang, Shuang; Hao, Jingcheng; Ngo, Huu Hao; Guo, Wenshan; Xu, Xiaoli; Wang, Qian; Wang, Jingmin

    2016-03-15

    Plants can bioaccumulate triclosan and bond with microbes and sediments in constructed wetlands (CWs) as well. However, little is known regarding the species-specific removal mechanism of CWs components and the selection of suitable wetland plant species for triclosan disposal. In this work, the use of bioaccumulation factors (BAFs) and biota to sediment accumulation factors (BSAFs) for choosing the best triclosan removal plant species was studied in laboratory-scale CWs. By the end of the experiment, over 80% of triclosan was removed and a specie-effect distribution was revealed in CWs with emergent, submerged and floating plants. By mass balance calculation, negative correlation between triclosan concentration in plants and degradation process was observed. The significant correlations between Log BSAFs values and triclosan concentration in plants or degradation contribution made it possible and reasonable in wetland plants selection. Introductions on plant species were provided considering the target removal process or regulation method. This work provided new information on plant species selection in CWs for triclosan removal or its emergency remediation by using bioaccumulative factors.

  10. Pathways regulating the removal of nitrogen in planted and unplanted subsurface flow constructed wetlands.

    PubMed

    Paranychianakis, Nikolaos V; Tsiknia, Myrto; Kalogerakis, Nicolas

    2016-10-01

    Single-stage constructed wetlands (CWs) are characterized by a low potential for N removal. Understanding the pathways regulating N cycling as well as their dependence on environmental variables might improve the potential of CWs for N removal and results in more accurate simulation tools. In this study we employed qPCR targeting marker functional genes (amoA, nirK, nirS, clade I and II nosZ) or microorganisms (anammox) regulating key pathways of N cycling to unravel their relative importance. Furthermore, the influence of plant species on treatment performance was studied. Our findings indicated nitrification-denitrification as the principal route of N removal in CWs, while anammox did not have a strong contribution. Evidence was also arisen that ammonia oxidizing archaea (AOA) contributed on NH3 oxidation. Overall, plant species had a weak effect on the abundance of N functional genes (amoA of AOA), but it strongly affected the performance of CWs in terms of N removal in the following order: unplanted < Phragmites communis < Typha latifolia. These findings suggest that plant species stimulate N removal by upregulating the rates that the responsible biochemical pathways operate, probably by increasing O2 supply. In addition, our study revealed differences in indicators linked to N2O emissions. The abundance of clade II nosZ genes remained low across the season scaling down a strong contribution in the reduction of the emitted N2O. The increasing ratios of nosZ/Σnir and nirS/nirK with the progress of season indicate a shift in the composition of denitrifiers towards strains with a lower genetic potential for N2O release. Similar trends were observed among the treatments but the mechanisms differed. The planted treatments stimulated an increase in the ΣnosZ/Σnir ratio, while the unplanted an increase in the nirS/nirK ratio. PMID:27379728

  11. Pathways regulating the removal of nitrogen in planted and unplanted subsurface flow constructed wetlands.

    PubMed

    Paranychianakis, Nikolaos V; Tsiknia, Myrto; Kalogerakis, Nicolas

    2016-10-01

    Single-stage constructed wetlands (CWs) are characterized by a low potential for N removal. Understanding the pathways regulating N cycling as well as their dependence on environmental variables might improve the potential of CWs for N removal and results in more accurate simulation tools. In this study we employed qPCR targeting marker functional genes (amoA, nirK, nirS, clade I and II nosZ) or microorganisms (anammox) regulating key pathways of N cycling to unravel their relative importance. Furthermore, the influence of plant species on treatment performance was studied. Our findings indicated nitrification-denitrification as the principal route of N removal in CWs, while anammox did not have a strong contribution. Evidence was also arisen that ammonia oxidizing archaea (AOA) contributed on NH3 oxidation. Overall, plant species had a weak effect on the abundance of N functional genes (amoA of AOA), but it strongly affected the performance of CWs in terms of N removal in the following order: unplanted < Phragmites communis < Typha latifolia. These findings suggest that plant species stimulate N removal by upregulating the rates that the responsible biochemical pathways operate, probably by increasing O2 supply. In addition, our study revealed differences in indicators linked to N2O emissions. The abundance of clade II nosZ genes remained low across the season scaling down a strong contribution in the reduction of the emitted N2O. The increasing ratios of nosZ/Σnir and nirS/nirK with the progress of season indicate a shift in the composition of denitrifiers towards strains with a lower genetic potential for N2O release. Similar trends were observed among the treatments but the mechanisms differed. The planted treatments stimulated an increase in the ΣnosZ/Σnir ratio, while the unplanted an increase in the nirS/nirK ratio.

  12. Coliform bacteria removal from sewage in constructed wetlands planted with Mentha aquatica.

    PubMed

    Avelar, Fabiana F; de Matos, Antonio T; de Matos, Mateus P; Borges, Alisson C

    2014-08-01

    The present study evaluated the performance of the species Mentha aquatica in constructed wetlands of horizontal subsurface flow (CW-HSSF) with regard to the removal of coliforms bacteria in an effluent from the primary treatment of sewage as well as to obtain adjustment parameters of the bacterial decay kinetic model along the length of the CW-HSSF. Therefore, four CW-HSSFs measuring 24.0 m x 1.0 m x 0.35 m were built and filled with number 0 gravel as the support medium to a height of 0.20m. Two of the CW-HSSFs were planted with the species M. aquatica, while the other two remained uncultivated. Cultivation of M. aquatica in CW-HSSF resulted in total coliforms (TC) and Escherichia coli (EC) removals from 0.9 to 1.3 log units greater than those obtained in the uncultivated experimental plots, for the hydraulic retention times (HRTs) of 4.5 and 6.0 days. For HRT ranged from 1.5 to 6.0 days, the highest removal efficiencies in counts of TC and EC were obtained when using longer HRT. The mathematical models evaluated showed good fit to average counts of TC and EC highlighting the modified first-order kinetic model with the inclusion of the power parameter in the HRT variable.

  13. Evaluation of clogging in planted and unplanted horizontal subsurface flow constructed wetlands: solids accumulation and hydraulic conductivity reduction.

    PubMed

    De Paoli, André Cordeiro; von Sperling, Marcos

    2013-01-01

    This study aimed to evaluate the behaviour of two horizontal subsurface flow constructed wetland units regarding solids build up and clogging of the filter medium. In order to analyse the causes of this process, which is considered the major operational problem of constructed wetlands, studies were carried out to characterize accumulated solids and hydraulic conductivity at specific points of the beds of two wetlands (planted with Typha latifolia and unplanted units) receiving effluent from an upflow anaerobic sludge blanket reactor treating sanitary sewage (population equivalent of 50 inhabitants each unit). The experiments were performed after the units were operating for 2 years and 4 months. This study presents comparative results related to the quantification and characterization of accumulated solids and hydraulic conductivity along the length and width of the filter beds. Approximately 80% of the solids found were inorganic (fixed). Near the inlet end, the rate interstitial solids/attached solids was 5.0, while in the outlet end it was reduced to 1.5. Hydraulic conductivity was lower near the inlet of the units (as expected) and, by comparing the planted wetland with the unplanted, the hydraulic conductivity was lower in the former, resulting in larger undesired surface flow.

  14. [Selection of winter plant species for wetlands constructed as sewage treatment systems and evaluation of their wastewater purification potentials].

    PubMed

    Chen, Yong-hua; Wu, Xiao-fu; Chen, Ming-li; Jiang, Li-juan; Li, Ke-lin; Lei, Dian; Wang, Hai-bin

    2010-08-01

    In order to establish an evaluation system for selection of winter wetland plants possessing high wastewater purification potentials in subtropics areas, designed sewage treatment experiments were carried out by introducing into the constructed wetlands 25 species of winter wetland plants. Cluster analysis was performed by including harmful environment-resistant enzyme and substrate enzyme activities into the commonly applied plant screening and assessment indexes system. The obtained results indicated that there were significant differences among the tested winter plants in their root length and vigor, leaf malonaldehyde (MDA), biomass, average nitrogen and phosphorus concentration and uptake, and urease and phosphoric acid enzyme activities in the root areas. Based on the established evaluation system, the tested plants were clustered into 3 groups. The plants in the 1st group possessing high purification potentials are Oenanthe javanica, Brassicacapestris, Juncus effusu, Saxifragaceae, Iris pseudoacorus, Osmanthus fragrans and Iris ensata; those in the 2nd group possessing moderate purification potentials are Brassica oleracea var acephala, Calendula officinalis, Aucuba japonica, Ligustrum lucidu, Beta vulgaris, Rhododendron simsii and Ilex latifolia; and those in the 3rd group with low purification potentials are Brassica oleracea var acephala, Calistephus chinensis, Rosa chinensis, Antirrhinums, Liriope palatyphylla, Zephyranthes candida, Fatshedera lizei, Petunia hybrida, Ilex quihoui, Dianthus caryophyllus and Loropetalum chinensis.

  15. [Selection of winter plant species for wetlands constructed as sewage treatment systems and evaluation of their wastewater purification potentials].

    PubMed

    Chen, Yong-hua; Wu, Xiao-fu; Chen, Ming-li; Jiang, Li-juan; Li, Ke-lin; Lei, Dian; Wang, Hai-bin

    2010-08-01

    In order to establish an evaluation system for selection of winter wetland plants possessing high wastewater purification potentials in subtropics areas, designed sewage treatment experiments were carried out by introducing into the constructed wetlands 25 species of winter wetland plants. Cluster analysis was performed by including harmful environment-resistant enzyme and substrate enzyme activities into the commonly applied plant screening and assessment indexes system. The obtained results indicated that there were significant differences among the tested winter plants in their root length and vigor, leaf malonaldehyde (MDA), biomass, average nitrogen and phosphorus concentration and uptake, and urease and phosphoric acid enzyme activities in the root areas. Based on the established evaluation system, the tested plants were clustered into 3 groups. The plants in the 1st group possessing high purification potentials are Oenanthe javanica, Brassicacapestris, Juncus effusu, Saxifragaceae, Iris pseudoacorus, Osmanthus fragrans and Iris ensata; those in the 2nd group possessing moderate purification potentials are Brassica oleracea var acephala, Calendula officinalis, Aucuba japonica, Ligustrum lucidu, Beta vulgaris, Rhododendron simsii and Ilex latifolia; and those in the 3rd group with low purification potentials are Brassica oleracea var acephala, Calistephus chinensis, Rosa chinensis, Antirrhinums, Liriope palatyphylla, Zephyranthes candida, Fatshedera lizei, Petunia hybrida, Ilex quihoui, Dianthus caryophyllus and Loropetalum chinensis. PMID:21090294

  16. Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species.

    PubMed

    Barbera, Antonio C; Borin, Maurizio; Cirelli, Giuseppe L; Toscano, Attilio; Maucieri, Carmelo

    2015-02-01

    This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m(-2)) followed by C. zizanioides (5.3 kg m(-2)) and C. papyrus (1.8 kg m(-2)). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m(-2), respectively, whereas M. giganteus emitted 3,395 g m(-2). Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m(-2) and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m(-2). The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m(-2)) followed by C. zizanioides (3.78 kg m(-2)) and C. papyrus (1.89 kg m(-2)). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth. PMID:24743957

  17. The Constructed Wetland Association UK database of constructed wetland systems.

    PubMed

    Cooper, P

    2007-01-01

    There are now more than 1,000 constructed wetland systems (CWs) in the UK. The first UK CW database was constructed by Water Research Centre (WRc) and Severn Trent Water Ltd to accompany a book on the design and performance of these systems. In that database, constructed by Gareth Job et al., only 154 beds were listed, most of which were tertiary sewage treatment sites in Severn Trent Water. The Constructed Wetland Association (CWA) was formed in 2000 as a UK water industry body in response to problems caused by unscrupulous constructors. A group of experienced, reputable designers and constructors formed the CWA to bring together best UK practice in order to counteract this problem. The group contains major water companies, designers, constructors, academics, plant growers and operators. They decided that one of the best ways of countering the problem was to assemble a database of design and performance from well-designed systems. After negotiation the CWA group took over responsibility for the database from WRc. The CWA has produced eight updates of the database which now contains information from more than 900 beds. It contains examples of the different variants of CWs in use in the UK. Most of these sites treat sewage/domestic wastewater but the database also includes examples of systems for the treatment of minewater, sludge, landfill leachate, industrial effluents, surface runoff and road runoff. Particular treatment applications are illustrated by case studies which are summary articles describing design, construction and performance. PMID:17802831

  18. [Development characteristics of aquatic plants in a constructed wetland for treating urban drinking water source at its initial operation stage].

    PubMed

    Zheng, Jun; Ma, Xin-Tang; Zhou, Lan; Zhou, Qing-Yuan; Wang, Zhong-Qiong; Wang, Wei-Dong; Yin, Cheng-Qing

    2011-08-01

    The development characteristics and improvement measures of aquatic plants were studied in Shijiuyang Constructed Wetland (SCW) at its initial operation stage. SCW was a large-scale wetland aiming to help relieve the source water pollution in Jiaxing City. A checklist of vascular plants in SCW was built, and species composition, life forms, biomass and association distributions were examined. Our objectives were to examine the diversity and community structure of aquatic plants in SCW at its initial operation stage, and to find out the possible hydrophyte improvement measures. The survey results showed that there were 49 vascular plant species belonging to 41 genera, 25 families in SCW, which greatly exceeded the artificially transplanted 13 species. The life forms of present aquatic plants in SCW were dominated by hygrophilous plants (20 species) and emerged plants (17 species), which accounted for 75.5% of the total number of aquatic plants. The aquatic plants transplanted artificially were dominated by emerged plants (accounted for 69.2%), while those naturally developed were predominated by hygrophilous plants (accounted for 47.2%). The horizontal distribution of aquatic plant community in SCW was mixed in the form of mosaics, which made up typical association complex. Except association Aeschynomene indica L., the dominant species of other associations were all those transplanted artificially. The naturally grown species scattered throughout the SCW and only occupied a small percentage. A marked difference was detected on the species and species richness of aquatic plants in different regions of SCW. Biomass of aquatic plant associations in SCW was 167.7 t. SCW has shown a trend of succession heading for quick increase of plant diversity at the primary operation stage. This trend provides a good material base for the future stable community of aquatic plants in SCW. According to the current status of aquatic plants, some suggestions were put forward on the

  19. Performance evaluation of planted and unplanted subsurface-flow constructed wetlands for the post-treatment of UASB reactor effluents.

    PubMed

    Dornelas, Filipe Lima; Machado, Matheus Boechat; von Sperling, Marcos

    2009-01-01

    A system comprised by a UASB (Upflow Anaerobic Sludge Blanket) reactor followed by two horizontal subsurface-flow constructed wetlands in parallel was evaluated for the treatment of the wastewater generated in the city of Belo Horizonte, Brazil (50 inhabitants each unit). One unit was planted (Typha latifolia) and the other was unplanted. Influent and effluent samples were collected for a period of seven months. The systems were able to produce final effluents with low concentrations of organic matter and suspended solids, but showed not to be efficient in the removal of nutrients. Mean effluent concentrations for the planted and unplanted units were, respectively: BOD: 15 and 19 mg/L; COD: 42 and 64 mg/L; TSS: 3 and 5 mg/L; TN: 27 and 33 mg/L; N-NH(3): 25 and 29 mg/L; P Total: 1.2 and 1.5 mg/L. The planted wetland presented effluent concentrations and removal efficiencies significantly (Wilcoxon matched-pairs test, 5% significance level) better than the unplanted unit for most constituents. The study shows that horizontal subsurface-flow constructed wetlands can be effectively used as a post-treatment option for the effluent from UASB reactors.

  20. Effects of plant biomass on nitrate removal and transformation of carbon sources in subsurface-flow constructed wetlands.

    PubMed

    Wen, Yue; Chen, Yi; Zheng, Nan; Yang, Dianhai; Zhou, Qi

    2010-10-01

    Denitrification is strongly dependent on carbon quantity and quality in most constructed wetlands (CWs). In this study, four batch CWs were designed, and were fed with nitrate-dominated water to investigate nitrate removal affected by plant and external cattail litter with or without alkali pretreatment. The results showed that the unit with plant and alkali-pretreated litter was more efficient in the initial stage whereas unit with plant and unpretreated litter was superior to other units in the middle and terminal stages. Plant accounted for less than 37% of the nitrate removal in biomass-up added CWs. The different nitrate removal rates were found to be greatly affected by the composition of the plant biomass as well as the quantity and quality of the available organic matters. It was also observed that plant biomass degradation over the period of this study resulted in various N species and concentrations in effluent.

  1. Effects of plant roots on the hydraulic performance during the clogging process in mesocosm vertical flow constructed wetlands.

    PubMed

    Hua, G F; Zhao, Z W; Kong, J; Guo, R; Zeng, Y T; Zhao, L F; Zhu, Q D

    2014-11-01

    The aim of this study was to evaluate the effects of plant roots (Typha angustifolia roots) on the hydraulic performance during the clogging process from the perspective of time and space distributions in mesocosm vertical flow-constructed wetlands with coarse sand matrix. For this purpose, a pair of lab-scale experiments was conducted to compare planted and unplanted systems by measuring the effective porosity and hydraulic conductivity of the substrate within different operation periods. Furthermore, the flow pattern of the clogging process in the planted and unplanted wetland systems were evaluated by their hydraulic performance (e.g., mean residence time, short circuiting, volumetric efficiency, number of continuously stirred tank reactors, and hydraulic efficiency factor) in salt tracer experiments. The results showed that the flow conditions would change in different clogging stages, which indicated that plants played different roles related to time and space. In the early clogging stages, plant roots restricted the flow of water, while in the middle and later clogging stages, especially the later stage, growing roots opened new pore spaces in the substrate. The roots played an important role in affecting the hydraulic performance in the upper layer (0-30 cm) where the sand matrix had a larger root volume fraction. Finally, the causes of the controversy over plant roots' effects on clogging were discussed. The results helped further understand the effects of plant roots on hydraulic performance during the clogging process.

  2. Constructed wetlands for the treatment of landfill leachate

    SciTech Connect

    Mulamoottil, G.; McBean, E.; Rovers, F.

    1998-12-31

    The book addresses leachate characteristics and the potential for treatability by constructed wetlands, the assessment of tolerance of wetland plants to the toxicity of leachates in differing climates, the role of plants in treatment of leachates, cost comparisons using wetland technology vs. traditional treatment and more.

  3. Feasibility of constructed wetland planted with Leersia hexandra Swartz for removing Cr, Cu and Ni from electroplating wastewater.

    PubMed

    You, Shao-Hong; Zhang, Xue-Hong; Liu, Jie; Zhu, Yi-Nian; Gu, Chen

    2014-01-01

    As a low-cost treatment technology for effluent, the constructed wetlands can be applied to remove the heavy metals from wastewater. Leersia hexandra Swartz is a metal-accumulating hygrophyte with great potential to remove heavy metal from water. In this study, two pilot-scale constructed wetlands planted with L. hexandra (CWL) were set up in greenhouse to treat electroplating wastewater containing Cr, Cu and Ni. The treatment performance of CWL under different hydraulic loading rates (HLR) and initial metal concentrations were also evaluated. The results showed that CWL significantly reduced the concentrations of Cr, Cu and Ni in wastewater by 84.4%, 97.1% and 94.3%, respectively. High HLR decreased the removal efficiencies of Cr, Cu and Ni; however, the heavy metal concentrations in effluent met Emission Standard of Pollutants for Electroplating in China (ESPE) at HLR less than 0.3 m3/m2 d. For the influent of 5 mg/L Cr, 10 mg/L Cu and 8 mg/L Ni, effluent concentrations were below maximum allowable concentrations in ESPE, indicating that the removal of Cr, Cu and Ni by CWL was feasible at considerably high influent metal concentrations. Mass balance showed that the primary sink for the retention of contaminants within the constructed wetland system was the sediment, which accounted for 59.5%, 83.5%, and 73.9% of the Cr, Cu and Ni, respectively. The data from the pilot wetlands support the view that CWL could be used to successfully remove Cr, Cu and Ni from electroplating wastewater.

  4. Effectiveness of Rice Agricultural Waste, Microbes and Wetland Plants in the Removal of Reactive Black-5 Azo Dye in Microcosm Constructed Wetlands.

    PubMed

    Saba, Beenish; Jabeen, Madeeha; Khalid, Azeem; Aziz, Irfan; Christy, Ann D

    2015-01-01

    Azo dyes are commonly generated as effluent pollutants by dye using industries, causing contamination of surface and ground water. Various strategies are employed to treat such wastewater; however, a multi-faceted treatment strategy could be more effective for complete removal of azo dyes from industrial effluent than any single treatment. In the present study, rice husk material was used as a substratum in two constructed wetlands (CWs) and augmented with microorganisms in the presence of wetland plants to effectively treat dye-polluted water. To evaluate the efficiency of each process the study was divided into three levels, i.e., adsorption of dye onto the substratum, phytoremediation within the CW and then bioremediation along with the previous two processes in the augmented CW. The adsorption process was helpful in removing 50% dye in presence of rice husk while 80% in presence of rice husk biocahr. Augmentation of microorganisms in CW systems has improved dye removal efficiency to 90%. Similarly presence of microorganisms enhanced removal of total nitrogen (68% 0 and Total phosphorus (75%). A significant improvement in plant growth was also observed by measuring plant height, number of leaves and leave area. These findings suggest the use of agricultural waste as part of a CW substratum can provide enhanced removal of textile dyes.

  5. Behaviour of pharmaceuticals and personal care products in constructed wetland compartments: Influent, effluent, pore water, substrate and plant roots.

    PubMed

    Hijosa-Valsero, María; Reyes-Contreras, Carolina; Domínguez, Carmen; Bécares, Eloy; Bayona, Josep M

    2016-02-01

    Seven mesocosm-scale constructed wetlands (CWs) with different design configurations, dealing with primary-treated urban wastewater, were assessed for the concentration, distribution and fate of ten pharmaceutical and personal care products (PPCPs) [ibuprofen, ketoprofen, naproxen, diclofenac, salicylic acid, caffeine, carbamazepine, methyl dihydrojasmonate, galaxolide and tonalide] and eight of their transformation products (TPs). Apart from influent and effluent, various CW compartments were analysed, namely, substrate, plant roots and pore water. PPCP content in pore water depended on the specific CW configuration. Macrophytes can take up PPCPs through their roots. Ibuprofen, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide were present on the root surface with a predominance of galaxolide and caffeine in all the planted systems. Naproxen, ibuprofen, salicylic acid, methyl dihydrojasmonate, galaxolide and tonalide were uptaken by the roots. In order to better understand the removal processes, biomass measurement and biodegradability studies through the characterization of internal-external isomeric linear alkylbenzenes present on the gravel bed were performed. Three TPs namely, ibuprofen-amide, 3-ethylbenzophenone and 4-hydroxy-diclofenac were identified for the first time in wetland pore water and effluent water, which suggests de novo formation (they were not present in the influent). Conversely, O-desmethyl-naproxen was degraded through the wetland passage since it was detected in the influent but not in the subsequent treatment stages. Biodegradation pathways are therefore suggested for most of the studied PPCPs in the assessed CWs.

  6. Behaviour of pharmaceuticals and personal care products in constructed wetland compartments: Influent, effluent, pore water, substrate and plant roots.

    PubMed

    Hijosa-Valsero, María; Reyes-Contreras, Carolina; Domínguez, Carmen; Bécares, Eloy; Bayona, Josep M

    2016-02-01

    Seven mesocosm-scale constructed wetlands (CWs) with different design configurations, dealing with primary-treated urban wastewater, were assessed for the concentration, distribution and fate of ten pharmaceutical and personal care products (PPCPs) [ibuprofen, ketoprofen, naproxen, diclofenac, salicylic acid, caffeine, carbamazepine, methyl dihydrojasmonate, galaxolide and tonalide] and eight of their transformation products (TPs). Apart from influent and effluent, various CW compartments were analysed, namely, substrate, plant roots and pore water. PPCP content in pore water depended on the specific CW configuration. Macrophytes can take up PPCPs through their roots. Ibuprofen, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide were present on the root surface with a predominance of galaxolide and caffeine in all the planted systems. Naproxen, ibuprofen, salicylic acid, methyl dihydrojasmonate, galaxolide and tonalide were uptaken by the roots. In order to better understand the removal processes, biomass measurement and biodegradability studies through the characterization of internal-external isomeric linear alkylbenzenes present on the gravel bed were performed. Three TPs namely, ibuprofen-amide, 3-ethylbenzophenone and 4-hydroxy-diclofenac were identified for the first time in wetland pore water and effluent water, which suggests de novo formation (they were not present in the influent). Conversely, O-desmethyl-naproxen was degraded through the wetland passage since it was detected in the influent but not in the subsequent treatment stages. Biodegradation pathways are therefore suggested for most of the studied PPCPs in the assessed CWs. PMID:26702554

  7. Effect of different plant species on nutrient removal and rhizospheric microorganisms distribution in horizontal-flow constructed wetlands.

    PubMed

    Meng, Panpan; Hu, Wenrong; Pei, Haiyan; Hou, Qingjie; Ji, Yan

    2014-01-01

    Three macrophyte species, Phragmites australis, Arundo donax L., and Typha latifolia L. have been separately grown in a horizontal-flow (HF) constructed wetland (CW) fed with domestic wastewater to investigate effects of plant species on nutrient removal and rhizospheric microorganisms. All the three mesocosms have been in operation for eight months under the loading rates of 1.14 g Nm(-2) d(-1) and 0.014gP m(-2) d(-1). Appropriately 34-43% phosphorus (P) was removed in HF CWs, and no distinct difference was found among the plants. In the growing season, A. donax L. removed 31.19 gm(-2) of nitrogen (N), followed by P. australis (29.96 g m(-2)), both of which were significantly higher than T. latifolia L. (7.21 g m(-2). Depending on the species, plants absorbed 1.73-7.15% of the overall N, and 0.06-0.56% of the P input. At least 10 common dominant microorganisms were found in the rhizosphere of all the three plants, and 6 of the 10 kinds of bacteria had close relationship with denitrifying bacteria, implying that denitrifiers were dominant microorganism distributed in rhizosphere of wetland plants.

  8. The role of plant uptake on the removal of organic matter and nutrients in subsurface flow constructed wetlands: a simulation study.

    PubMed

    Langergraber, G

    2005-01-01

    Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.

  9. Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Effect of flow configuration and plant species.

    PubMed

    Chen, Jun; Ying, Guang-Guo; Wei, Xiao-Dong; Liu, You-Sheng; Liu, Shuang-Shuang; Hu, Li-Xin; He, Liang-Ying; Chen, Zhi-Feng; Chen, Fan-Rong; Yang, Yong-Qiang

    2016-11-15

    This study aims to investigate the removal of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale constructed wetlands (CWs) with different flow configurations or plant species including the constructed wetland with or without plant. Six mesocosm-scale CWs with three flow types (surface flow, horizontal subsurface flow and vertical subsurface flow) and two plant species (Thaliadealbata Fraser and Iris tectorum Maxim) were set up in the outdoor. 8 antibiotics including erythromycin-H2O (ETM-H2O), monensin (MON), clarithromycin (CTM), leucomycin (LCM), sulfamethoxazole (SMX), trimethoprim (TMP), sulfamethazine (SMZ) and sulfapyridine (SPD) and 12 genes including three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), two chloramphenicol resistance genes (cmlA and floR) and 16S rRNA (bacteria) were determined in different matrices (water, particle, substrate and plant phases) from the mesocosm-scale systems. The aqueous removal efficiencies of total antibiotics ranged from 75.8 to 98.6%, while those of total ARGs varied between 63.9 and 84.0% by the mesocosm-scale CWs. The presence of plants was beneficial to the removal of pollutants, and the subsurface flow CWs had higher pollutant removal than the surface flow CWs, especially for antibiotics. According to the mass balance analysis, the masses of all detected antibiotics during the operation period were 247,000, 4920-10,600, 0.05-0.41 and 3500-60,000μg in influent, substrate, plant and effluent of the mesocosm-scale CWs. In the CWs, biodegradation, substrate adsorption and plant uptake all played certain roles in reducing the loadings of nutrients, antibiotics and ARGs, but biodegradation was the most important process in the removal of these pollutants. PMID:27443461

  10. Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Effect of flow configuration and plant species.

    PubMed

    Chen, Jun; Ying, Guang-Guo; Wei, Xiao-Dong; Liu, You-Sheng; Liu, Shuang-Shuang; Hu, Li-Xin; He, Liang-Ying; Chen, Zhi-Feng; Chen, Fan-Rong; Yang, Yong-Qiang

    2016-11-15

    This study aims to investigate the removal of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale constructed wetlands (CWs) with different flow configurations or plant species including the constructed wetland with or without plant. Six mesocosm-scale CWs with three flow types (surface flow, horizontal subsurface flow and vertical subsurface flow) and two plant species (Thaliadealbata Fraser and Iris tectorum Maxim) were set up in the outdoor. 8 antibiotics including erythromycin-H2O (ETM-H2O), monensin (MON), clarithromycin (CTM), leucomycin (LCM), sulfamethoxazole (SMX), trimethoprim (TMP), sulfamethazine (SMZ) and sulfapyridine (SPD) and 12 genes including three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), two chloramphenicol resistance genes (cmlA and floR) and 16S rRNA (bacteria) were determined in different matrices (water, particle, substrate and plant phases) from the mesocosm-scale systems. The aqueous removal efficiencies of total antibiotics ranged from 75.8 to 98.6%, while those of total ARGs varied between 63.9 and 84.0% by the mesocosm-scale CWs. The presence of plants was beneficial to the removal of pollutants, and the subsurface flow CWs had higher pollutant removal than the surface flow CWs, especially for antibiotics. According to the mass balance analysis, the masses of all detected antibiotics during the operation period were 247,000, 4920-10,600, 0.05-0.41 and 3500-60,000μg in influent, substrate, plant and effluent of the mesocosm-scale CWs. In the CWs, biodegradation, substrate adsorption and plant uptake all played certain roles in reducing the loadings of nutrients, antibiotics and ARGs, but biodegradation was the most important process in the removal of these pollutants.

  11. Experiences with constructed wetland systems in Korea

    NASA Astrophysics Data System (ADS)

    Youngchul, Kim; Gilson, Hwang; Jin-Woo, Lee; Je-Chul, Park; Dong-Sup, Kim; Min-Gi, Kang; in-Soung, Chang

    2006-10-01

    In spite of the low temperature during the winter season and the high land environment, the wetland treatment system is gaining popularity in Korea because of its lower construction cost and simplicity in operation and maintenance. Many different types of wetland treatment systems have been built during the last 10 years, among which the free water surface wetland has been predominant. Most of the large-scale systems are government projects for improving the water quality of the streams flowing into the estuary dikes and reservoirs. The covering plants used in this system are different in different areas but cattails and reeds or their combinations are common. Constructed wetlands in Korea can be characterized by their shallow depths and short hydraulic residence times. There is no established flow pattern and configuration rules for constructing wetlands, but many efforts have been made with a view to improving their ecological function. Flow control is the most difficult problem in designing a riverbed or riparian wetland. There have been scores of flow rate control devices developed for wetlands, but none of them guarantee wetlands’ safety against flooding. In earlier wetland construction, the building materials were mainly soil. Recently, strong and durable building materials such as rocks, gravel beds, concrete and steel are used at vulnerable places to protect them from erosion. Our investigation indicated that the wetland system would be an appropriate technology because it is not only cheaper to construct, but also requires less maintenance work. However, we suffer from the reduced effectiveness in performance during the winter. We need to evaluate the partial treatment accomplished during 6 to 7 months per year.

  12. Accumulation of Metals and Boron in Phragmites australis Planted in Constructed Wetlands Polishing Real Electroplating Wastewater.

    PubMed

    Sochacki, Adam; Guy, Bernard; Faure, Olivier; Surmacz-Górska, Joanna

    2015-01-01

    The concentration of metals (Al, Cu, Fe, Mn, Ni, Zn) and B were determined in the above- and belowground biomass of Phragmites australis collected from the microcosm constructed wetland system used for the polishing of real electroplating wastewater. Translocation factor and bioconcentration factor were determined. Pearson correlation test was used to determine correlation between metal concentration in substrate and above- and belowground parts of Phragmites australis. The obtained results suggested that Phragmites australis did not play a major role as an accumulator of metals. It was observed also that the substrate could have exerted an effect on the translocation of Ni, Cu, Zn and Mn. The analysed concentrations of metals and B in biomass were in the range or even below the concentrations reported in the literature with the exception of Ni. The aboveground biomass was found suitable as a composting input in terms of metals concentrations.

  13. ENGINEERING BULLETIN: CONSTRUCTED WETLANDS TREATMENT

    EPA Science Inventory

    Constructed wetlands have been demonstrated effective in removing organic, metal, and nutrient elements including nitrogen and phosphorus from municipal wastewaters, mine drainage, industrial effluents, and agricultural runoff. The technology is waste stream-specific, requiring...

  14. Effect of plant harvesting on the performance of constructed wetlands during winter: radial oxygen loss and microbial characteristics.

    PubMed

    Wang, Qian; Xie, Huijun; Zhang, Jian; Liang, Shuang; Ngo, Huu Hao; Guo, Wenshan; Liu, Chen; Zhao, Congcong; Li, Hao

    2015-05-01

    The aboveground tissue of plants is important for providing roots with constant photosynthetic resources. However, the aboveground biomass is usually harvested before winter to maintain the permanent removal of nutrients. In this work, the effects of harvest on plants' involvement in oxygen input as well as in microbial abundance and activity were investigated in detail. Three series of constructed wetlands with integrated plants ("unharvested"), harvested plants ("harvested"), and fully cleared plants ("cleared") were set up. Better performance was found in the unharvested units, with the radial oxygen loss (ROL) rates ranging from 0.05 to 0.59 μmol O₂/h/plant, followed by the harvested units that had relatively lower ROL rates (0.01 to 0.52 μmol O₂/h/plant). The cleared units had the lowest removal efficiency, which had no rhizome resources from the plants. The microbial population and activity were highest in the unharvested units, followed by the harvested and cleared units. Results showed that bacterial abundances and enhanced microbial activity were ten times higher on root surfaces compared with sands. These results indicate that late autumn harvesting of the aboveground biomass exhibited negative effects on plant ROL as well as on the microbial population and activity during the following winter.

  15. Evaluation of PPCPs removal in a combined anaerobic digester-constructed wetland pilot plant treating urban wastewater.

    PubMed

    Reyes-Contreras, C; Matamoros, V; Ruiz, I; Soto, M; Bayona, J M

    2011-08-01

    The removal efficiency of 16 pharmaceuticals and personal care products (PPCPs) from urban wastewater (dissolved and particulate phases) was evaluated for the first time in a hybrid pilot plant consisting of an upflow anaerobic sludge blanket reactor followed by two sequentially connected horizontal flow constructed wetlands: a surface flow wetland (SF CW) and a subsurface flow wetland (SSF CW). Whereas the PPCP removal associated with the dissolved phase exhibited a seasonal pattern, the fraction associated with the suspended solids showed less seasonality. In the dissolved phase, the overall removal efficiency in summer ranged from 70% to 85% for salicylic acid (SAL), methyl dihydrojasmonate, caffeine (CAF), ketoprofen and triclosan, whereas in winter it declined for most of the PPCPs to between 30% and 50%, except for CAF and SAL (>80%) and carbamazepine and butylated hydroxyl toluene (11-18%). In the suspended solids, the removal exceeded 80% for most of the target PPCPs. The efficiency of the different treatment steps was also compound-dependent, but the SF CW generally exhibited the highest removal efficiency for most of the contaminants analyzed. The characterization of the organic matter retained in the wetland gravel beds revealed the occurrence of hydrophobic contaminants such as phthalate esters and fragrances at moderate concentrations (i.e., up to 3.5 μg kg(-1)), which declined strongly over the course of the different treatment steps. In the SF CW, the net mass accumulation rates of tonalide and galaxolide were 4 and 23 gy(-1) respectively, whereas in the SSF CW they were 0.3 and 1.8 gy(-1) respectively.

  16. MANUAL - CONSTRUCTED WETLANDS TREATMENT OF MUNICIPAL WASTEWATERS

    EPA Science Inventory

    Constructed wetlands are man-made wastewater treatment systems. They usually have one or more cells less than 1 meter deep and are planted with aquatic greenery. Water outlet structures control the flow of wastewater through the system to keep detention times and water levels at ...

  17. Phytoremediation of explosive contaminated groundwater in constructed wetlands: I - batch study

    SciTech Connect

    Sikora, F.J.; Berends, L.L.; Phillips, W.D.; Kelly, D.A.; Coonrod, H.S.

    1995-06-01

    The study evaluates the utility of constructed wetlands for remediating constructed wetlands using bench scale wetlands (batch type). Specifically the study examines: the degradation of TNT and RDX in contaminated waters in a variety of wetland types; the impact of wetland type on chemical oxygen demand; and tracks the level of degradation products in various wetland types. The study also provides design recommendations for the wetlands demonstration project to be located at the Milan Army Ammunition Plant (MAAP), in Tennessee.

  18. Comparison between polishing (maturation) ponds and subsurface flow constructed wetlands (planted and unplanted) for the post-treatment of the effluent from UASB reactors.

    PubMed

    von Sperling, M; Dornelas, F L; Assunção, F A L; de Paoli, A C; Mabub, M O A

    2010-01-01

    This paper presents the results of a comparison of the performance of two treatment systems operating in parallel, with the same influent wastewater. The investigated systems are (i) UASB + three polishing ponds in series + coarse filter (200 population equivalents) and (ii) UASB + subsurface flow constructed wetlands (50 population equivalents). Two wetland units, operating in parallel, were analysed, being one planted (Typha latifolia) and the other unplanted. The systems were located in Belo Horizonte, Brazil. The wetland systems showed to be more efficient in the removal of organic matter and suspended solids, leading to good effluent BOD and COD concentrations and excellent SS concentrations. The planted wetland performed better than the unplanted unit, but the latter was also able to provide a good effluent quality. The polishing pond system was more efficient in the removal of nitrogen (ammonia) and coliforms (E. coli). Land requirements and cost considerations are presented.

  19. Constructed wetlands as biofuel production systems

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Wu, Xu; Chang, Jie; Gu, Baojing; Min, Yong; Ge, Ying; Shi, Yan; Xue, Hui; Peng, Changhui; Wu, Jianguo

    2012-03-01

    Clean biofuel production is an effective way to mitigate global climate change and energy crisis. Progress has been made in reducing greenhouse-gas (GHG) emissions and nitrogen fertilizer consumption through biofuel production. Here we advocate an alternative approach that efficiently produces cellulosic biofuel and greatly reduces GHG emissions using waste nitrogen through wastewater treatment with constructed wetlands in China. Our combined experimental and literature data demonstrate that the net life-cycle energy output of constructed wetlands is higher than that of corn, soybean, switchgrass, low-input high-diversity grassland and algae systems. Energy output from existing constructed wetlands is ~237% of the input for biofuel production and can be enhanced through optimizing the nitrogen supply, hydrologic flow patterns and plant species selection. Assuming that all waste nitrogen in China could be used by constructed wetlands, biofuel production can account for 6.7% of national gasoline consumption. We also find that constructed wetlands have a greater GHG reduction than the existing biofuel production systems in a full life-cycle analysis. This alternative approach is worth pursuing because of its great potential for straightforward operation, its economic competitiveness and many ecological benefits.

  20. The inhibition and adaptability of four wetland plant species to high concentration of ammonia wastewater and nitrogen removal efficiency in constructed wetlands.

    PubMed

    Wang, Yuhui; Wang, Junfeng; Zhao, Xiaoxiang; Song, Xinshan; Gong, Juan

    2016-02-01

    Four plant species, Typha orientalis, Scirpus validus, Canna indica and Iris tectorum were selected to assess their physiological response and effects on nitrogen and COD removal to high total ammoniacal nitrogen (TAN) in constructed wetlands. Results showed that high TAN caused decreased relative growth rate, net photosynthetic rate, and leaf transpiration. C. indica and T. orientalis showed higher TAN adaptability than S. validus and I. tectorum. Below TAN of 200 mg L(-1), growth of C. indica and T. orientalis was less affected or even stimulated at TAN range 100-200 mg L(-1). However, S. validus and I. tectorum was obviously suppressed when TAN was above 100 mg L(-1). High TAN generated obvious oxidative stress showing increased proline and malondialdehyde contents, and superoxide dismutase was inhibited. It indicated that the threshold for plant self-bioremediation against high TAN was 200 mg L(-1). What's more, planted CWs showed higher nitrogen and COD removal. Removal rate of C. indica and T. orientalis was higher than S. validus and I. tectorum.

  1. Effect of photosynthetically elevated pH on performance of surface flow-constructed wetland planted with Phragmites australis.

    PubMed

    Yin, Xiaole; Zhang, Jian; Hu, Zhen; Xie, Huijun; Guo, Wenshan; Wang, Qingsong; Ngo, Huu Hao; Liang, Shuang; Lu, Shaoyong; Wu, Weizhong

    2016-08-01

    Combination of emergent and submerged plants has been proved to be able to enhance pollutant removal efficiency of surface flow-constructed wetland (SFCW) during winter. However, intensive photosynthesis of submerged plants during summer would cause pH increase, which may have adverse effects on emergent plants. In this study, nitrogen transformation of lab-scale SFCW under pH gradient of 7.5, 8.5, 9.5 and 10.5 was systematically investigated. The results showed that total nitrogen (TN) removal efficiency decreased from 76.3 ± 0.04 to 51.8 ± 0.04 % when pH increased from 7.5 to 10.5, which was mainly attributed to plant assimilation decay and inhibition of microbe activities (i.e., nitrite-oxidizing bacteria and denitrifiers). Besides, the highest sediment adsorption in SFCW was observed at pH of 8.5. In general, the combination of submerged and emergent plants is feasible for most of the year, but precaution should be taken to mitigate the negative effect of high alkaline conditions when pH rises to above 8.5 in midsummer.

  2. Water quality in a surface-flow constructed treatment wetland polishing tertiary effluent from a municipal wastewater treatment plant.

    PubMed

    Beutel, Marc W

    2012-01-01

    Constructed treatment wetlands (CTWs) are unique ecotechnologies that can sustainably treat a range of wastewaters. This study focused on a 0.23 ha vegetated surface-flow CTW polishing nitrate-rich (3-6 mg-N/L) tertiary effluent from a municipal wastewater treatment plant. Water quality was monitored longitudinally in the fall of 2009 and 2010. The CTW cooled water by from around 20 °C to <15 °C in both years. Longitudinal temperature profiles were successfully modeled using an energy balance approach (2009 R(2) = 0.69; 2010 R(2) = 0.92). The magnitude of key model fitting parameters, including albedo (0.1-0.2) and convective transfer coefficient (0.1-0.9 MJ/m(2) d °C), were within ranges reported in the literature. In both years, dissolved oxygen decreased through the wetland from 6-7 mg/L to 3-4 mg/L, yielding an oxygen mass consumption rate of 0.08-0.09 g/m(2) d. Longitudinal nitrate profiles were well represented by the P-k-C* model (2009 R(2) = 0.88; 2010 R(2) = 0.92). First order removal rates were 20.2 m/yr in 2009 and 29.0 m/yr in 2010 at a P value of 6.0. Levels of ammonia and total phosphorus increased negligibly through the wetland, remaining below 0.25 mg/L. This study shows that vegetated surface-flow CTWs are well suited to cool and polish low-BOD nitrate-dominated tertiary effluents with little degradation of other water quality parameters of concern, including phosphorus and ammonia. PMID:22925872

  3. Changes in the bacterial community structure in two-stage constructed wetlands with different plants for industrial wastewater treatment.

    PubMed

    Calheiros, Cristina S C; Duque, Anouk F; Moura, Alexandra; Henriques, Isabel S; Correia, António; Rangel, António O S S; Castro, Paula M L

    2009-07-01

    This study focused on the diversity of bacterial communities from two series of two-stage constructed wetlands (CWs) treating tannery wastewater, under different hydraulic conditions. Series were separately planted with Typha latifolia and Phragmites australis in expanded clay aggregates and operated for 31 months. The effect of plant species, hydraulic loading and unit stage on bacterial communities was addressed through bacterial enumeration and denaturating gradient gel electrophoresis (DGGE). Diverse and distinct bacterial communities were found in each system unit, which was related in part to the type of plant and stage position (first or second unit in the series). Numerical analysis of DGGE profiles showed high diversity in each unit with an even distribution of species. No clear relation was established between the sample collection time, hydraulic loading applied and the bacterial diversity. Isolates retrieved from plant roots and substrates of CWs were affiliated with gamma-Proteobacteria, Firmicutes, alpha-Proteobacteria, Sphingobacteria, Actinobacteria and Bacteroidetes. Both series were effective in removing organic matter from the inlet wastewater, however, based on batch degradation experiments it seems that biodegradation was limited by the recalcitrant properties of the wastewater.

  4. Removal of metals in constructed wetlands

    SciTech Connect

    Crites, R.W.; Watson, R.C.; Williams, C.R.

    1996-12-31

    Trace metals are difficult to remove from municipal wastewater by conventional wastewater treatment methods. Constructed wetlands have the potential to trap and remove metals from the water column. Long term removal is expected to occur by accumulation and burial in the plant detritus in a manner similar to the removal of phosphorus. Few data are available in the literature on removal of metals by constructed wetlands. A free water surface constructed wetland at Sacramento Regional Wastewater Treatment Plant treating secondary municipal effluent has been operating since the spring of 1994. Removal data for 13 metals are presented for the period from August 1994 to May 1995. About 3,785 m{sup 3}/d (1 mgd) of pure oxygen activated sludge effluent, disinfected using UV light, is further treated through a 8 ha (20 acre) constructed wetlands Ten separate, parallel treatment cells are available to demonstrate the effects of detention time, vegetation management, and application frequency on the removal of metals, organics and ammonia. Detention time can be varied from 3 to 13 days by varying the flow and the water depth. The vegetation, primarily bulrush with some cattails, will be managed by different techniques to minimize mosquito production. Application frequency varies from continuous flow to batch flow (1 to 2 days of loading with 1 day of discharge).

  5. Wetlands: water, wildlife, plants, & people

    USGS Publications Warehouse

    Vandas, Stephen; Farrar, Frank

    1996-01-01

    Wetlands are part of all our lives. They can generally be described as transitional areas between land and deepwater habitats. There are many different kinds of wetlands, and they can be found in many different habitat types, from forests to deserts; some are maintained by saltwater, others by freshwater. This poster shows general types of diverse wetlands and demonstrates how people and wetlands can benefit by living together. The diversity of plants and animals is shown in cartooned pictures. As with plants and animals, there are many different common names for the various wetland types. The common names used on this poster were used by the U.S. Fish and Wildlife Service in the publication "Wetlands-Status and Trends in the Conterminous United States, Mid-1970's to Mid-1980's." Estuarine wetland types--salt marshes and mangrove swamps--are labeled in red letters. The estuary is where ocean saltwater and river freshwater mix. The estuary is labeled in orange letters. The inland wetland types-inland marshes and wet meadows, forested wetlands, and shrub wetlands-are labeled in yellow. Other wetlands are present in rivers, lakes, and reservoirs. The water bodies associated with these wetlands are labeled in black. The poster is folded into 8.5" x 11" panels; front and back panels can easily be photocopied.

  6. Effects of plant biomass on nitrogen transformation in subsurface-batch constructed wetlands: a stable isotope and mass balance assessment.

    PubMed

    Chen, Yi; Wen, Yue; Zhou, Qi; Vymazal, Jan

    2014-10-15

    Nitrate is commonly found in the influent of subsurface-batch constructed wetlands (SSB CWs) used for tertiary wastewater treatments. To understand the effects of plants and the litter on nitrate removal, as well as on nitrogen transformation in SSB CWs, six laboratory-scale SSB CW microcosms were set up in duplicate and were operated as batch systems with hydraulic residence time (HRT) of 5d. The presence of Typha latifolia enhanced nitrate removal in SSB CWs, and the N removed by plant uptake was mainly stored in aboveground biomass. Typha litter addition greatly improved nitrate removal in SSB CWs through continuous input of labile organic carbon, and calculated enrichment factors (ε) were between -12.1‰--13.9‰ from the nitrogen stable isotope analysis, suggesting that denitrification plays a dominant role in the N removal. Most significantly, simultaneous sulfur-based autotrophic and heterotrophic denitrification was observed in CWs. Finally, mass balance showed that denitrification, sedimentation burial and plant uptake respectively contributed 54%-94%, 1%-46% and 7.5%-14.3% to the N removal in CWs.

  7. Forested wetlands constructed for mitigation of destroyed natural wetlands

    USGS Publications Warehouse

    Perry, M.C.; Pugh, S.B.; Deller, A.S.

    1995-01-01

    Forested wetlands constructed for mitigation were evaluated at six sites in Maryland to determine the success of these areas for providing suitable wildlife habitat. Natural forested wetlands were used as reference sites. Initial mortality of planted woody shrubs and trees was high (avg. 55%) and mostly attributed to excessive moisture. The number of woody seedlings from natural regeneration was inversely proportional to the amount of grass cover on the site, which was planted for erosion control. The number of volunteer woody seedlings was also inversely proportional to the distance from adjacent natural forests. Preliminary data indicate that cost does not support use of transplants and that enhancement of soil with organic supplements, followed by widespread and heavy seeding of woody plants would be more efficient and effective. Wildlife use of areas measured by avian surveys and trapping of mammals, reptiles, and amphibians showed that in general wildlife species were more representative of open grassland areas than forested habitats. Natural succession of the sites probably will take at least 20-30 years before typical values and functions of forested wetlands are obtained.

  8. Plant uptake of diclofenac in a mesocosm-scale free water surface constructed wetland by Cyperus alternifolius.

    PubMed

    Zhai, Jun; Rahaman, Md Hasibur; Ji, Jiucui; Luo, Zhiyoung; Wang, Quanfeng; Xiao, Haiwen; Wang, Kunping

    2016-01-01

    This study aimed to assess the uptake of diclofenac, a widely used nonsteroidal anti-inflammatory pharmaceutical, by a macrophyte Cyperus alternifolius in a mesocosm-scale free water surface (FWS) constructed wetland. Quantitative analysis of diclofenac concentrations in water solution and plant tissues was conducted by high performance liquid chromatography analysis after sample pre-treatment with solid-phase extraction and liquid extraction, respectively. The FWS with Cyperus alternifolius obtained a maximum 69.3% diclofenac removal efficiency, while a control system without plant only had a removal efficiency of 2.7% at the end of the experiment period of 70 days. Based on mass balance study of the experimental system, it was estimated that plant uptake and in-plant conversion of diclofenac contributed about 21.4% of the total diclofenac removal in the mesocosm while the remaining 78.6% diclofenac was eliminated through biotic and abiotic conversion of diclofenac in the water phase. Diclofenac on the root surface and in roots, stems and leaves of Cyperus alternifolius was found at the concentrations of 0.15-2.59 μg/g, 0.21-2.66 μg/g, 0.06-0.53 μg/g, and 0.005-0.02 μg/g of fresh weight of plant tissues, respectively. The maximum bioaccumulation factor of diclofenac was calculated in roots (21.04) followed by root surface (20.49), stems (4.19), and leaves (0.16), respectively. Diclofenac translocation potentiality from root to stem was found below 0.5, suggesting a slow and passive translocation process of diclofenac. Current study demonstrated high potential of Cyperus alternifolius for phytoremediation of diclofenac in FWS and can be applied in other engineered ecosystems. PMID:27332847

  9. Plant uptake of diclofenac in a mesocosm-scale free water surface constructed wetland by Cyperus alternifolius.

    PubMed

    Zhai, Jun; Rahaman, Md Hasibur; Ji, Jiucui; Luo, Zhiyoung; Wang, Quanfeng; Xiao, Haiwen; Wang, Kunping

    2016-01-01

    This study aimed to assess the uptake of diclofenac, a widely used nonsteroidal anti-inflammatory pharmaceutical, by a macrophyte Cyperus alternifolius in a mesocosm-scale free water surface (FWS) constructed wetland. Quantitative analysis of diclofenac concentrations in water solution and plant tissues was conducted by high performance liquid chromatography analysis after sample pre-treatment with solid-phase extraction and liquid extraction, respectively. The FWS with Cyperus alternifolius obtained a maximum 69.3% diclofenac removal efficiency, while a control system without plant only had a removal efficiency of 2.7% at the end of the experiment period of 70 days. Based on mass balance study of the experimental system, it was estimated that plant uptake and in-plant conversion of diclofenac contributed about 21.4% of the total diclofenac removal in the mesocosm while the remaining 78.6% diclofenac was eliminated through biotic and abiotic conversion of diclofenac in the water phase. Diclofenac on the root surface and in roots, stems and leaves of Cyperus alternifolius was found at the concentrations of 0.15-2.59 μg/g, 0.21-2.66 μg/g, 0.06-0.53 μg/g, and 0.005-0.02 μg/g of fresh weight of plant tissues, respectively. The maximum bioaccumulation factor of diclofenac was calculated in roots (21.04) followed by root surface (20.49), stems (4.19), and leaves (0.16), respectively. Diclofenac translocation potentiality from root to stem was found below 0.5, suggesting a slow and passive translocation process of diclofenac. Current study demonstrated high potential of Cyperus alternifolius for phytoremediation of diclofenac in FWS and can be applied in other engineered ecosystems.

  10. Bacterial community variation and microbial mechanism of triclosan (TCS) removal by constructed wetlands with different types of plants.

    PubMed

    Zhao, Congcong; Xie, HuiJun; Xu, Jingtao; Xu, Xiaoli; Zhang, Jian; Hu, Zhen; Liu, Cui; Liang, Shuang; Wang, Qian; Wang, Jingmin

    2015-02-01

    Triclosan (TCS) is a broad-spectrum synthetic antimicrobial agent that is toxic to microbes and other aquatic organisms. Constructed wetlands (CWs) are now popular in TCS removal. However, knowledge on the effects of TCS on the bacterial community and microbial removal mechanism in CWs is lacking. The effects of TCS (60 μg L(-1)) on bacterial communities in batch-loaded CWs with emergent (Typha angustifolia), submerged (Hydrilla verticillata), and floating plant (Salvinia natans) were analyzed by 454 pyrosequencing technology. After six periods of experiment, the TCS removal efficiencies were over 90% in CWs, and negative effects of TCS on bacterial community richness and diversity were observed. Moreover, plant species effect existed. Bacterial strains that contributed to TCS biodegradation in CWs were successfully identified. In TCS-treated T. angustifolia and H. verticillata CWs, beta-Proteobacteria increased by 16.63% and 18.20%, respectively. In TCS-treated S. natans CWs, delta- and gamma-Proteobacteria and Sphingobacteria increased by 9.36%, 19.49%, and 31.37%, respectively, and could relate to TCS biodegradation. TCS affected the development of certain bacteria, and eventually, the bacterial community structures in CWs. This research provided ecologically relevant information on bacterial community and microbial removal mechanism in CWs under TCS treatment.

  11. Estimating evapotranspiration in natural and constructed wetlands

    USGS Publications Warehouse

    Lott, R. Brandon; Hunt, Randall J.

    2001-01-01

    Difficulties in accurately calculating evapotranspiration (ET) in wetlands can lead to inaccurate water balances—information important for many compensatory mitigation projects. Simple meteorological methods or off-site ET data often are used to estimate ET, but these approaches do not include potentially important site-specific factors such as plant community, root-zone water levels, and soil properties. The objective of this study was to compare a commonly used meterological estimate of potential evapotranspiration (PET) with direct measurements of ET (lysimeters and water-table fluctuations) and small-scale root-zone geochemistry in a natural and constructed wetland system. Unlike what has been commonly noted, the results of the study demonstrated that the commonly used Penman combination method of estimating PET underestimated the ET that was measured directly in the natural wetland over most of the growing season. This result is likely due to surface heterogeneity and related roughness efffects not included in the simple PET estimate. The meterological method more closely approximated season-long measured ET rates in the constructed wetland but may overestimate the ET rate late in the growing season. ET rates also were temporally variable in wetlands over a range of time scales because they can be influenced by the relation of the water table to the root zone and the timing of plant senescence. Small-scale geochemical sampling of the shallow root zone was able to provide an independent evaluation of ET rates, supporting the identification of higher ET rates in the natural wetlands and differences in temporal ET rates due to the timing of senescence. These discrepancies illustrate potential problems with extrapolating off-site estimates of ET or single measurements of ET from a site over space or time.

  12. [Problems and countermeasures in the application of constructed wetlands].

    PubMed

    Huang, Jin-Lou; Chen, Qin; Xu, Lian-Huang

    2013-01-01

    Constructed wetlands as a wastewater eco-treatment technology are developed in recent decades. It combines sewage treatment with the eco-environment in an efficient way. It treats the sewage effectively, and meanwhile beautifies the environment, creates ecological landscape, and brings benefits to the environment and economics. The unique advantages of constructed wetlands have attracted intensive attention since developed. Constructed wetlands are widely used in treatment of domestic sewage, industrial wastewater, and wastewater from mining and petroleum production. However, many problems are found in the practical application of constructed wetland, e. g. they are vulnerable to changes in climatic conditions and temperature, their substrates are easily saturated and plugged, they are readily affected by plant species, they often occupy large areas, and there are other problems including irrational management, non-standard design, and a single function of ecological service. These problems to a certain extent influence the efficiency of constructed wetlands in wastewater treatment, shorten the life of the artificial wetland, and hinder the application of artificial wetland. The review presents correlation analysis and countermeasures for these problems, in order to improve the efficiency of constructed wetland in wastewater treatment, and provide reference for the application and promotion of artificial wetland.

  13. Molybdenum(VI) removal by using constructed wetlands with different filter media and plants.

    PubMed

    Lian, J J; Xu, S G; Zhang, Y M; Han, C W

    2013-01-01

    The efficacy and capacity of vertical-flow wetland filters on molybdenum (Mo) removal from wastewater was examined, employing reed (Phragmites australis) and cattail (Typha latifolia) as well as different adsorption granular media. Humus, cinder, modified cinder, as well as pyrite were used as filter media. A synthetic effluent with different concentrations of Mo(VI) at different hydraulic retention times was used for simulating Mo leached mine wastewater. Laboratory experiments showed that the equilibrium adsorption data were in agreement with the Langmuir isotherm model, and the maximum Mo(VI) adsorption capacities of modified cinder and pyrite were 10.01 and 6.25 mg/g, respectively. Mo(VI) removal in F5 (combination substrates of pyrite and cinder) was found to be more stable and effective than that of F1 (conventional gravel and soil filter media) during the 14-week experiment. Most of the Mo(VI) was retained in the 10-20 cm of the substrate, and adsorbed by the modified cinder and pyrite. The largest fraction of Mo(VI) retained was the water-soluble fraction on the surface of the pyrite. Cattail was more suitable for Mo(VI) absorption than reed, but the bioaccumulation accounted for a very small portion of the total removal.

  14. High performance constructed wetlands for cold climates.

    PubMed

    Jenssen, Petter D; Maehlum, Trend; Krogstad, Tore; Vråle, Lasse

    2005-01-01

    In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway. Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance even during winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by a subsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according to present guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40-60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved.

  15. Retention and mitigation of metals in sediment, soil, water, and plant of a newly constructed root-channel wetland (China) from slightly polluted source water.

    PubMed

    Wang, Baoling; Wang, Yu; Wang, Weidong

    2014-01-01

    Constructed root-channel wetland (CRCW) is a term for pre-pond/wetland/post-pond complexes, where the wetland includes plant-bed/ditch landscape and root-channel structure. Source water out of pre-ponds flows through alternate small ditches and plant beds with root-channels via a big ditch under hydraulic regulation. Then source water flows into post-ponds to finish final polishing. This article aims to explore the potential of components of a pilot CRCW in China on mitigating metals in micro-polluted source water during its initial operation stage. We investigated six heavy metals (Cd, Cr, Cu, Ni, Zn, and Pb) in surface sediment, plant-bed subsurface soil, water, and aquatic plants during 2012-2013. Monitoring results showed that pond/ditch sediments and plant-bed soil retained a significant amount of Cr, Ni, and Zn with 93.1%, 72.4%, and 57.5% samples showing contamination factor above limit 1 respectively. Remarkably the high values of metal enrichment factor (EF) occurred in root-channel zones. Water monitoring results indicated that Ni, Zn, and Pb were removed by 78.5% (66.7%), 57.6% (59.6%), and 26.0% (7.5%) in east (west) wetland respectively. Mass balance estimation revealed that heavy metal mass in the pond/ditch sediments accounted for 63.30% and that in plant-bed soil 36.67%, while plant uptake occupied only 0.03%. The heavy metal accretion flux in sediments was 0.41 - 211.08 μg · cm(-2) · a(-1), less than that in plant-bed soil (0.73 - 543.94 μg · cm(-2) · a(-1)). The 1.83 ha wetland has retained about 86.18 kg total heavy metals within 494 days after operation. This pilot case study proves that constructed root-channel wetland can reduce the potential ecological risk of purified raw water and provide a new and effective method for the removal of heavy metals from drinking water sources. PMID:25032090

  16. Improving low-temperature performance of surface flow constructed wetlands using Potamogeton crispus L. plant.

    PubMed

    Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Yin, Xiaole

    2016-10-01

    In this study, enhanced organics and nitrogen removal efficiency in SFCWs by different submerged plants for polluted river water treatment under cold temperature was evaluated. High average removal efficiencies of COD (92.45%), NH4(+)-N (93.70%) and TN (55.62%) were achieved in experimental SFCWs with Potamogeton crispus compared with SFCWs with other plants. SFCWs with underground Phragmites australis root also presented better performance than the unplanted systems, indicating its positive role of contamination removal in winter. The results of this study indicated SFCWs with hardy submerged plant P. crispus could be a more effective and sustainable strategy for removing organics and nitrogen in shallow nutrient enriched river water ecosystems under cold climate. PMID:27381001

  17. Improving low-temperature performance of surface flow constructed wetlands using Potamogeton crispus L. plant.

    PubMed

    Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Yin, Xiaole

    2016-10-01

    In this study, enhanced organics and nitrogen removal efficiency in SFCWs by different submerged plants for polluted river water treatment under cold temperature was evaluated. High average removal efficiencies of COD (92.45%), NH4(+)-N (93.70%) and TN (55.62%) were achieved in experimental SFCWs with Potamogeton crispus compared with SFCWs with other plants. SFCWs with underground Phragmites australis root also presented better performance than the unplanted systems, indicating its positive role of contamination removal in winter. The results of this study indicated SFCWs with hardy submerged plant P. crispus could be a more effective and sustainable strategy for removing organics and nitrogen in shallow nutrient enriched river water ecosystems under cold climate.

  18. Influence of season and plant species on the abundance and diversity of sulfate reducing bacteria and ammonia oxidizing bacteria in constructed wetland microcosms.

    PubMed

    Faulwetter, Jennifer L; Burr, Mark D; Parker, Albert E; Stein, Otto R; Camper, Anne K

    2013-01-01

    Constructed wetlands offer an effective means for treatment of wastewater from a variety of sources. An understanding of the microbial ecology controlling nitrogen, carbon and sulfur cycles in constructed wetlands has been identified as the greatest gap for optimizing performance of these promising treatment systems. It is suspected that operational factors such as plant types and hydraulic operation influence the subsurface wetland environment, especially redox, and that the observed variation in effluent quality is due to shifts in the microbial populations and/or their activity. This study investigated the biofilm associated sulfate reducing bacteria and ammonia oxidizing bacteria (using the dsrB and amoA genes, respectively) by examining a variety of surfaces within a model wetland (gravel, thick roots, fine roots, effluent), and the changes in activity (gene abundance) of these functional groups as influenced by plant species and season. Molecular techniques were used including quantitative PCR and denaturing gradient gel electrophoresis (DGGE), both with and without propidium monoazide (PMA) treatment. PMA treatment is a method for excluding from further analysis those cells with compromised membranes. Rigorous statistical analysis showed an interaction between the abundance of these two functional groups with the type of plant and season (p < 0.05). The richness of the sulfate reducing bacterial community, as indicated by DGGE profiles, increased in planted vs. unplanted microcosms. For ammonia oxidizing bacteria, season had the greatest impact on gene abundance and diversity (higher in summer than in winter). Overall, the primary influence of plant presence is believed to be related to root oxygen loss and its effect on rhizosphere redox.

  19. In situ biodegradation of perchloroethylene in constructed wetland mesocosms

    SciTech Connect

    Hoylman, A.M.; Rosensteel, B.A.; Trettin, C.C.

    1994-12-31

    Anaerobic reductive dehalogenation initiates degradation of highly chlorinated organic compounds. Subsequent intermediate chlorinated compounds are in turn more readily degraded in aerobic environments. Thus, complete degradation of chlorinated compounds to nontoxic end products requires both anaerobic and aerobic environments. These environments are provided by constructed wetland bioremediation systems, which through the interaction of vegetation, microbial, chemical, and physical processes, result in waste water renovation. The authors integrated the ecological engineering technology of constructed wetland systems with developments in plant-rhizosphere degradation of organic contaminants to examine the effectiveness of constructed wetland systems for in situ bioremediation of waste water contaminated with a chlorinated hydrocarbon, perchloroethylene (PCE) and an aromatic hydrocarbon, toluene. A mesocosm was designed to provide sequential anaerobic and vegetated-aerobic cells with complete control of water and gas flux and to emulate wetland properties such as hydric soil composition, physicochemical parameters, and the presence of wetland vegetation (Eleocharis acicularis). Treatments included contaminated and non-contaminated wetland cells and sterile controls. The fate and transport of PCE, toluene, and metabolic by-products were determined in effluent and chamber headspace, and extracts of soil and plant tissue. These analyses provide the basis for evaluating contaminant fate in wetland systems. Manipulation of aeration and hydrologic regimes in the wetland cells will facilitate testing conditions that affect degradation processes. The experimental apparatus is a innovative design for experimentation on the degradation of volatile organic compounds in plant-soil systems.

  20. Microbial community structure accompanied with electricity production in a constructed wetland plant microbial fuel cell.

    PubMed

    Lu, Lu; Xing, Defeng; Ren, Zhiyong Jason

    2015-11-01

    This study reveals the complex structure of bacterial and archaeal communities associated with a Canna indica plant microbial fuel cell (PMFC) and its electricity production. The PMFC produced a maximum current of 105 mA/m(2) by utilizing rhizodeposits as the sole electron donor without any external nutrient or buffer supplements, which demonstrates the feasibility of PMFCs in practical oligotrophic conditions with low solution conductivity. The microbial diversity was significantly higher in the PMFC than non-plant controls or sediment-only controls, and pyrosequencing and clone library reveal that rhizodeposits conversion to current were carried out by syntrophic interactions between fermentative bacteria (e.g., Anaerolineaceae) and electrochemically active bacteria (e.g., Geobacter). Denitrifying bacteria and acetotrophic methanogens play a minor role in organics degradation, but abundant hydrogenotrophic methanogens and thermophilic archaea are likely main electron donor competitors.

  1. Application of constructed wetlands for wastewater treatment in Nepal.

    PubMed

    Shrestha, R R; Haberl, R; Laber, J; Manandhar, R; Mader, J

    2001-01-01

    Surface water pollution is one of the serious environmental problems in urban centers in Nepal due to the discharge of untreated wastewater into the river-system, turning them into open sewers. Wastewater treatment plants are almost non-existent in the country except for a few in the Kathmandu Valley and even these are not functioning well. Successful implementation of a few constructed wetland systems within the past three years has attracted attention to this promising technology. A two-staged subsurface flow constructed wetland for hospital wastewater treatment and constructed wetlands for treatment of greywater and septage is now becoming a demonstration site of constructed wetland systems in Nepal. Beside these systems, five constructed wetlands have already been designed and some are under construction for the treatment of leachate and septage in Pokhara municipality, wastewater in Kathmandu University, two hospitals and a school. This paper discusses the present condition and treatment performance of constructed wetlands that are now in operation. Furthermore, the concept of the treatment wetlands under construction is also described here. With the present experience, several recommendations are pointed out for the promotion of this technology in the developing countries.

  2. Review of Constructed Subsurface Flow vs. Surface Flow Wetlands

    SciTech Connect

    HALVERSON, NANCY

    2004-09-01

    The purpose of this document is to use existing documentation to review the effectiveness of subsurface flow and surface flow constructed wetlands in treating wastewater and to demonstrate the viability of treating effluent from Savannah River Site outfalls H-02 and H-04 with a subsurface flow constructed wetland to lower copper, lead and zinc concentrations to within National Pollutant Discharge Elimination System (NPDES) Permit limits. Constructed treatment wetlands are engineered systems that have been designed and constructed to use the natural functions of wetlands for wastewater treatment. Constructed wetlands have significantly lower total lifetime costs and often lower capital costs than conventional treatment systems. The two main types of constructed wetlands are surface flow and subsurface flow. In surface flow constructed wetlands, water flows above ground. Subsurface flow constructed wetlands are designed to keep the water level below the top of the rock or gravel media, thus minimizing human and ecological exposure. Subsurface flow wetlands demonstrate higher rates of contaminant removal per unit of land than surface flow (free water surface) wetlands, therefore subsurface flow wetlands can be smaller while achieving the same level of contaminant removal. Wetlands remove metals using a variety of processes including filtration of solids, sorption onto organic matter, oxidation and hydrolysis, formation of carbonates, formation of insoluble sulfides, binding to iron and manganese oxides, reduction to immobile forms by bacterial activity, and uptake by plants and bacteria. Metal removal rates in both subsurface flow and surface flow wetlands can be high, but can vary greatly depending upon the influent concentrations and the mass loading rate. Removal rates of greater than 90 per cent for copper, lead and zinc have been demonstrated in operating surface flow and subsurface flow wetlands. The constituents that exceed NPDES limits at outfalls H-02 a nd H

  3. Field application of a planted fixed bed reactor (PFR) for support media and rhizosphere investigation using undisturbed samples from full-scale constructed wetlands.

    PubMed

    Barreto, A B; Vasconcellos, G R; von Sperling, M; Kuschk, P; Kappelmeyer, U; Vasel, J L

    2015-01-01

    This study presents a novel method for investigations on undisturbed samples from full-scale horizontal subsurface-flow constructed wetlands (HSSFCW). The planted fixed bed reactor (PFR), developed at the Helmholtz Center for Environmental Research (UFZ), is a universal test unit for planted soil filters that reproduces the operational conditions of a constructed wetland (CW) system in laboratory scale. The present research proposes modifications on the PFR original configuration in order to allow its operation in field conditions. A mobile device to obtain undisturbed samples from real-scale HSSFCW was also developed. The experimental setting is presented with two possible operational configurations. The first allows the removal and replacement of undisturbed samples in the CW bed for laboratory investigations, guaranteeing sample integrity with a mobile device. The second allows the continuous operation of the PFR and undisturbed samples as a fraction of the support media, reproducing the same environmental conditions outside the real-scale system. Investigations on the hydrodynamics of the adapted PFR were carried out with saline tracer tests, validating the proposed adaptation. Six adapted PFR units were installed next to full-scale HSSFCW beds and fed with interstitial liquid pumped from two regions of planted and unplanted support media. Fourteen points were monitored along the system, covering carbon fractions, nitrogen and sulfate. The results indicate the method as a promising tool for investigations on CW support media, rhizosphere and open space for studies on CW modeling, respirometry, kinetic parameters, microbial communities, redox potential and plant influence on HSSFCW. PMID:26247753

  4. Hexachlorobenzene dechlorination in constructed wetland mesocosms.

    PubMed

    Zhou, Yuanqing; Tigane, Triin; Li, Xiuzhen; Truu, Marika; Truu, Jaak; Mander, Ulo

    2013-01-01

    We studied the dechlorination of hexachlorobenzene (HCB) in wetland mesocosm (MC) trials filled with sediment (well mineralized homogenized peat mixed with mud) from a wastewater treatment wetland located in a floodplain: three MCs were planted with common reed (Phragmites australis) and another three with broad-leaved cattail (Typha latifolia). According to the rootzone development we distinguished between the upper (0-10 cm from the soil surface) and lower layers (20-30 cm). Over 36 days, the initial measured concentration of HCB was reduced to 61%, 51%, 42% and 40% in the lower layer without roots of Phragmites, in the lower layer with roots of Typha, in the upper layer with roots of Typha, and in the upper layer with roots of Phragmites respectively. The 90% degradation time (DT(90)) of the initial measured HCB can be calculated as 192, 121, 110 and 92 days (d) respectively. PeCB, 1, 2, 3, 4-, 1, 2, 3, 5- and 1, 2, 4, 5-TeCB, and 1, 2, 3-, 1, 2, 4- and 1, 3, 5-TCB were the main dechlorination products detected in MC sediment samples. The dechlorination rates of HCB were higher in sediment layers with well-developed root zones. According to the DT(50) of 28-58 days and DT(90) of 92-192 days, HCB can be considered to be a less persistent organic pollutant in constructed wetlands.

  5. Ten years experience of treating all flows from combined sewerage systems using package plant and constructed wetland combinations.

    PubMed

    Griffin, P

    2003-01-01

    Severn Trent Water have been using constructed wetlands since 1991 as part of a flowsheet in which 6 DWF (Dry Weather Flow) is treated by rotating biological contactors (RBCs), and constructed reed beds used to provide both tertiary treatment and stormwater treatment. The company now has over 50 such sites using this flowsheet. Dimensioning and effluent quality achievable is reported and data presented showing the performance of reed beds treating stormwater alone or in admixture with RBC effluent. After 8-10 years of operation the condition of a number of storm reed beds was assessed to determine the remaining asset life. The majority seem likely to achieve at least another five years of operation before further review is needed.

  6. Use of Constructed Wetlands for Polishing Recharge Wastewater

    NASA Astrophysics Data System (ADS)

    Cardwell, W.

    2009-12-01

    The use of constructed wetlands for waste water treatment is becoming increasingly popular as more focus is being shifted to natural means of waste treatment. These wetlands employ processes that occur naturally and effectively remove pollutants and can greatly minimize costs when compared to full scale treatment plants. Currently, wetland design is based on basic “rules-of-thumb,” meaning engineers have a general understanding but not necessarily a thorough knowledge of the intricate physical, biological, and chemical processes involved in these systems. Furthermore, there is very little consideration given to use the wetland as a recharge pond to allow the treated water to percolate and recharge the local groundwater aquifers. The City of Foley, located in Alabama, and the Utilities Board of the City of Foley partnered with Wolf Bay Watershed Watch to evaluate alternative wastewater effluent disposal schemes. Rather than discharging the treated water into a local stream, a pilot program has been developed to allow water from the treatment process to flow into a constructed wetlands area where, after natural treatment, the treated water will then be allowed to percolate into a local unconfined aquifer. The goal of this study is to evaluate how constructed wetlands can be used for “polishing” effluent as well as how this treated water might be reused. Research has shown that constructed wetlands, with proper design and construction elements, are effective in the treatment of BOD, TSS, nitrogen, phosphorous, pathogens, metals, sulfates, organics, and other substances commonly found in wastewater. Mesocosms will be used to model the wetland, at a much smaller scale, in order to test and collect data about the wetland treatment capabilities. Specific objectives include: 1. Determine optimum flow rates for surface flow wetlands where water treatment is optimized. 2. Evaluate the capabilities of constructed wetlands to remove/reduce common over the counter

  7. Native plants for effective coastal wetland restoration

    USGS Publications Warehouse

    Howard, Rebecca J.

    2003-01-01

    Plant communities, along with soils and appropriate water regimes, are essential components of healthy wetland systems. In Louisiana, the loss of wetland habitat continues to be an issue of major concern. Wetland loss is caused by several interacting factors, both natural and human-induced (e.g., erosion and saltwater intrusion from the construction of canals and levees). Recent estimates of annual coastal land loss rates of about 62 km2 (24 mi2 ) over the past decade emphasize the magnitude of this problem. In an attempt to slow the rate of loss and perhaps halt the overall trend, resource managers in Louisiana apply various techniques to restore damaged or degraded habitats to functioning wetland systems.Researchers at the U.S. Geological Survey’s National Wetlands Research Center (NWRC) have cooperated with the Louisiana Department of Natural Resources in studies that address effective restoration strategies for coastal wetlands. The studies have identified differences in growth that naturally exist in native Louisiana wetland plant species and genetic varieties (i.e., clones) within species. Clones of a species have a distinctive genetic identity, and some clones may also have distinctive growth responses under various environmental conditions (i.e., preferences). Indeed, large areas of coastal marsh are typically populated by several clones of a plant species, each growing in a microenvironment suited to its preferences.These studies will provide information that will assist resource managers in selecting plant species and clones of species with known growth characteristics that can be matched to environmental conditions at potential restoration sites. Before the studies began, a collection of several clones from four plant species native to coastal Louisiana was established. The species collected included saltgrass (Distichlis spicata), common reed (Phragmites australis), giant bulrush (Schoenoplectus californicus), and saltmarsh bulrush (Schoenoplectus

  8. A Constructed Wetland: From Monitoring To Action.

    ERIC Educational Resources Information Center

    Kowal, Dan

    1998-01-01

    Presents a water-quality monitoring project in a Denver school that has evolved into an experiment using a constructed wetland system to treat the acid-mine drainage from an abandoned gold mine. (PVD)

  9. Microbial biomass, activity and community composition in constructed wetlands.

    PubMed

    Truu, Marika; Juhanson, Jaanis; Truu, Jaak

    2009-06-15

    The aim of the current article is to give an overview about microbial communities and their functioning but also about factors affecting microbial activity in the three most common types (surface flow and two types of sub-surface flow) of constructed wetlands. The paper reviews the community composition and structural diversity of the microbial biomass, analyzing different aspects of microbial activity with respect to wastewater properties, specific wetland type, and environmental parameters. A brief introduction about the application of different novel molecular techniques for the assessment of microbial communities in constructed wetlands is also given. Microbially mediated processes in constructed wetlands are mainly dependent on hydraulic conditions, wastewater properties, including substrate and nutrient quality and availability, filter material or soil type, plants, and different environmental factors. Microbial biomass is within similar ranges in both horizontal and vertical subsurface flow and surface flow constructed wetlands. Stratification of the biomass but also a stratified structural pattern of the bacterial community can be seen in subsurface flow systems. Microbial biomass C/N ratio is higher in horizontal flow systems compared to vertical flow systems, indicating the structural differences in microbial communities between those two constructed wetland types. The total activity of the microbial community is in the same range, but heterotrophic growth is higher in the subsurface (vertical flow) system compared to the surface flow systems. Available species-specific data about microbial communities in different types of wetlands is scarce and therefore it is impossible make any general conclusions about the dynamics of microbial community structure in wetlands, its relationship to removal processes and operational parameters.

  10. Effects of open water on the performance of a constructed wetland for nonpoint source pollution control.

    PubMed

    Kim, H C; Yoon, C G; Son, Y K; Rhee, H P; Lee, S B

    2010-01-01

    The seasonal performance of four differently configured constructed wetland systems was compared for the treatment efficiency of nonpoint source pollution. Dead plants in the constructed wetlands increased the nitrogen removal rate during winter by providing organic carbon, which is essential for the denitrification process. However, when the wetlands released phosphorus from the dead plants, the removal rate of phosphorus decreased. After seven growing seasons, plant coverage was nearly 100%, and the dissolved oxygen (DO) concentration was lowered to 1.3-5.4 mg/L. Open-water sections were then constructed inside the wetlands, which resulted in enhanced DO concentrations as well as improved treatment efficiency of nutrients and biochemical oxygen demand (BOD). Overall, performance of the constructed wetland was improved BOD, total nitrogen, and total phosphorus with the establishment of open water sections in the constructed wetland system.

  11. Modeling pollutant fate and transport in constructed wetlands

    SciTech Connect

    Brown, R.T.; Field, J.J.; Zanoli, M.J.; Crites, R.W.

    1994-12-31

    The Constructed Wetlands Fate and Aquatic Transport Evaluation Model (CWFATE) was developed to evaluate alternative design and operations of the constructed wetlands treatment system (CWTS) at the Sacramento Regional Wastewater Treatment Plant in Elk Grove, California. The model simulates the daily fate and transport of metals and other influent pollutants in an effort to predict CWTS effluent concentrations, removal efficiency, and long-term bioaccumulation of pollutants in sediment, vegetation, organic material, and aquatic organisms. Due to the difficulty of obtaining scientific information for model verification, final calibration is postponed until further field data become available.

  12. Performance and behaviour of planted and unplanted units of a horizontal subsurface flow constructed wetland system treating municipal effluent from a UASB reactor.

    PubMed

    da Costa, Jocilene Ferreira; de Paoli, André Cordeiro; Seidl, Martin; von Sperling, Marcos

    2013-01-01

    A system composed of two horizontal subsurface flow constructed wetlands operating in parallel was evaluated for the post-treatment of UASB (upflow anaerobic sludge blanket) reactor effluent, for a population equivalent of 50 inhabitants per unit. One unit was planted with cattail (Typha latifolia) and the other was unplanted. The study was undertaken over a period of 4 years, comprising monitoring of influent and effluent constituents together with a full characterization of the behaviour of the units (tracer studies, mathematical modelling of chemical oxygen demand (COD) decay, characterization of solids in the filter medium). The mean value of the surface hydraulic load was 0.11 m(3)m(-2)d(-1), and the theoretical hydraulic retention time was 1.1 d in each unit. Using tracer tests with (82)Br, dispersion number (d) values of 0.084 and 0.079 for the planted and unplanted units were obtained, indicating low to moderate dispersion. The final effluent had excellent quality in terms of organic matter and suspended solids, but the system showed low capacity for nitrogen removal. Four-year mean effluent concentration values from the planted and unplanted units were, respectively: biochemical oxygen demand (BOD(5)): 25 and 23 mg L(-1); COD: 50 and 55 mg L(-1); total suspended solids (TSS): 9 and 9 mg L(-1); N-ammonia: 27 and 28 mg L(-1). The COD decay coefficient K for the traditional plug-flow model was 0.81 and 0.84 d(-1) for the planted and unplanted units. Around 80% of the total solids present in the filter medium were inorganic, and most of them were present in the interstices rather than attached to the support medium. As an overall conclusion, horizontal subsurface flow wetlands can be a very suitable post-treatment method for municipal effluents from anaerobic reactors.

  13. Constructed wetlands for treating acid drainage at TVA Facilities: Progress report

    SciTech Connect

    Tomljanovich, D.A.; Brodie, G.A.; Hammer, D.A.

    1988-03-01

    A comprehensive overview is presented of TVA's use of constructed wetlands to naturally treat water quality problems associated with acid drainage at its fossil plants and the inactive Fabius Coal Mine and Preparation Plant in Jackson County, Alabama. TVA constructed its first wetland in May 1985. As of December 1987, a total of eight constructed wetlands, one enhanced natural wetland receiving acid drainage, and one former chemical treatment pond were being monitored as treatment wetlands. Some measure of success is being achieved at all the wetland systems. However, to achieve compliance quality effluent (total Fe <3.0 mg/L, total Mn <2.0 mg/L, pH 6.0--9.0 s.u., and total suspended solids <32.0 mg/L) interim chemical treatment is being used at COF to treat manganese, and at WCF to treat low pH. At KIF, water is being pumped from the final cell of the wetland to the active ashpond as an interim measure until it is shown to consistently yield compliance quality effluent. Chemical treatment is also being used to augment wetlands treatment at the Fabius Impoundment 2 and Impoundment 4 wetlands. Where chemical treatment is required, reduced chemical costs result from some level of wetlands treatment. Successful wetlands treatment has been demonstrated at three sites, where no chemical treatment is required. In the remaining two newly constructed wetlands, insufficient data exist to assess their treatment capability. Overall average construction cost based on nine wetlands was $1.13/ft/sup 2/ ($49,223/ac). Before converting one chemical treatment pond (Fabius Impoundment 3) to a wetland, TVA was annually spending $12,000 to $15,000 for chemicals and $10,000 for pond maintenance that failed to maintain complying discharges. Complying discharges and an annual wetland maintenance cost of about $1000 make the wetland an attractive and cost-beneficial treatment method. 2 refs., 15 figs., 10 tabs.

  14. Constructed wetlands to control nonpoint-source pollution

    SciTech Connect

    Wengrzynek, R.L.

    1991-01-01

    The use of land for agriculture, urban development, and recreational purposes results in pollution that has potential to contaminate groundwater, streams, lakes and oceans. Aquatic ecosystems can be damaged by even small amounts of pollutants in runoff during storms and by cumulative impacts of chronic, low levels of pollution. Nutrients, pesticides and sediments can have long term effects on the ecosystems. The instant invention using constructed wetlands has been particularly useful for purposes of protecting ecosystems from untoward effects of nonpoint source pollution. The construct, containing in hydraulic order a sediment basin, level-lip spreader, grassy filter, wetland, and deep pond can be used to remove pollutants from nonpoint source runoff. Wetlands are planted with vegetation that encourages growth of aerobic and anaerobic bacteria, which are helpful in removing and detoxifying contaminants.

  15. Hydraulic characteristics of a constructed wetland: Implications for pollutant removal

    NASA Astrophysics Data System (ADS)

    Wachniew, P.; Czuprynski, P.; Maloszewski, P.; Ozimek, T.

    2003-04-01

    Constructed wetlands are built in order to treat wastewaters of various origin with some degree of control over purification processes. Treatment wetlands improve water quality through removal of suspended solids, organics, nitrogen, phosphorus, pathogens (bacteria, parasites, viruses) and metals. Transformation and removal of pollutants from wastewaters occur via numerous interrelated physical, chemical and biological processes. The efficiency of soluble pollutants removal is related to the degree of contact between wastewaters and the reactive surfaces. Therefore knowledge of hydraulic phenomena is crucial in studies of wetland functioning. A subsurface flow wetland in Nowa Slupia, Poland was studied in order to find out relationships between hydraulic phenomena and wetland performance. The wetland consists of three parallel gravel beds overgrown by common reed with a total surface area of 6400 sq m, total active volume of around 900 cubic m and the average loading of around 4 l/s. Three tracer tests with bromide and tritium accompanied by observations of water quality, plant distribution and biomass were performed in summer and winter conditions. Tracer breakthrough curves obtained from tracer tests were used to identify sub-systems within the wetland and to infer their hydraulic properties (water residence times, active volumes, dispersive characteristics). Three reed beds receive different wastewater loadings and show different water residence times and dispersive characteristics. Wastewater flow occurs partly via surface overflow with apparent stagnant zones and preferential flow pathways. These flow patterns are reflected in complex structure of breakthrough curves. Inhomogenous wastewater distribution within the wetland is due to operation practices and clogging of the gravel beds with refractory organic matter. Observations of effluent water quality, plant distribution and biomass reflect these apparent inhomogenities in wastewater flow patterns. This work

  16. Constructed wetland technology transfer to Nepal.

    PubMed

    Shrestha, R R; Haberl, R; Laber, J

    2001-01-01

    Constructed Wetland (CW) technology is still not wide spread in developing countries despite having great potential. This paper describes an approach carried out in Nepal to transfer CW technology for wastewater treatment. Three CWs (hospital wastewater treatment--20 m3/d, greywater treatment of a single household, septage treatment--40 m3/d) were built and two have been investigated so far. All systems are subsurface flow systems with at least one vertical flow stage. Their treatment efficiency turned out to be very high. Median load elimination rates of the hospital wastewater and greywater treatment plants were for TSS: 97 to 99%; BOD5: 97 to 99%; COD: 94 to 97%; NH4-N 80 to 99%; PO4-P: 5 to 69%; Total Coliforms: 99.87 to 99.999% (3-5 log steps). Beside the treatment task the plants play an important role as demonstration sites to make common people and especially decision makers aware of the existing environmental problems and one possible solution. Several recommendations are pointed out to promote the technology in developing countries.

  17. compartment transfer rates in horizontal flow constructed wetlands

    NASA Astrophysics Data System (ADS)

    Maier, Uli; Oswald, Sascha; Thullner, Martin; Grathwohl, Peter

    2010-05-01

    A conceptual computer model has been constructed to simulate the compartment transfer rates in horizontal flow constructed wetlands. The model accounts for flow and transport in the variably saturated porous medium as well as biogeochemical change reactions. The most concentrated contaminants such as BTEX, MTBE and gasoline hydrocarbons and dissolved as well as mineral phase electron acceptors are considered. Also of major interest are reduced species with high oxygen demand such as ammonium. The influence of marsh plants on microbial activity, gas transport, water balance and contaminant fate in general is matter of current investigation. The constructed wetlands consist of a coarse sand or fine gravel porous medium. Marsh plants were introduced after installation, however, a number of control basins are operated unplanted. Water levels and through flow rates are adjusted to optimize the remediation efficiency. The system is likely to be neither reaction nor mixing limited, thus both, values of dispersivity and degradation kinetics may be crucial for remediation efficiency. Biogeochemical modelling is able to delineate in detail (i) the zonation of processes, (ii) temporal variation (breakthrough curves) and (iii) mass balance information. The contributions of biodegradation and volatilisation and the influence of plants (compartment transfer) can generally best be evaluated by the component's mass balance. More efficient mixing is expected in the wetlands with open water body which leads to both, more biodegradation and volatilisation. An important task is to quantify the role of plants and root systems for contaminant attenuation in constructed wetlands. The long term goal of investigation is to allow for predictions for the design of large scale compartment transfer wetlands that may be applied to remediate the site as a whole.

  18. Phytoremediation of explosives contaminated groundwater in constructed wetlands: 2. Flow through study. Draft report

    SciTech Connect

    DBehrends, L.L.; Sikora, F.J.; Phillips, W.D.; Baily, E.; McDonald, C.

    1996-02-01

    This study evaluates the utility of constructed wetlands for remediating explosives contaminated groundwaters using bench scale flow-through type reactors. Specifially the study examines: the degradation of TNT, TNB, RDX, and HMX in contaminated waters in plant lagoons and gravel-based wetlands. The study also provides design recommendations for the wetland demonstration project to be located at the Milan Army Ammunition Plant (MAAP), in Tennessee.

  19. Macroinvertebrates Associated With Emergent Macrophyte Decomposition in a Constructed Wetland.

    NASA Astrophysics Data System (ADS)

    Nelson, M.; Thullen, J.; Sartoris, J.

    2005-05-01

    This study took place at the San Jacinto constructed wetland in California. Wetland water is supplied to irrigators in this cooperative venture between Reclamation and the Eastern Municipal Water District. One of the problems at this highly productive site is that plant litter accumulates to where it needs to be managed by taking the wetland off-line, thus impacting O&M costs and water delivery schedules for extended periods. Information on decomposition rates and conditions needed to encourage invertebrate decomposers was required to improve wetland reliability and decrease biomass management costs. Standing dead culms of bulrush (Schoenoplectus) were collected and air-dried to constant weight. Twenty-gram culm packs were placed in the wetland and then collected at two month intervals. Comparisons between fine-mesh and coarse-mesh packs demonstrated that exclusion of aquatic invertebrates decreased processing. This was also demonstrated in laboratory studies. It also appeared that culm pack decomposition rate varied with the macroinvertebrate community, and that community distribution was influenced by water quality. Study results confirm the importance of vegetation management through water management and wetland design. Maintaining healthy, sustainable ecosystems will help to encourage natural decomposition processes and maintain better water quality.

  20. Constructed wetland design: The first generation

    SciTech Connect

    Reed, S.C.; Brown, D.S.

    1992-01-01

    A recent inventory, sponsored by the U.S. EPA Risk Reduction Engineering Laboratory in Cincinnati, OH documented the presence of over 150 constructed wetlands systems in the U.S., for the treatment of municipal and industrial wastewaters. The total flow received by these systems is about 400,000 cu m/d (100 mgd). This paper summarizes some of the results from the inventory, including: location, type, vegetation, design flow, loading rates, and costs for wetland systems where this information was available. The paper also discusses some 'lessons learned' from site visits to several of the systems.

  1. Vegetation changes and partitioning of selenium in 4-year-old constructed wetlands treating agricultural drainage.

    PubMed

    Lin, Z Q; Terry, N; Gao, S; Mohamed, S; Ye, Z H

    2010-03-01

    The knowledge of selenium (Se) partitioning in treatment wetlands and wetland vegetation management are essential for long-term effective operation of constructed wetlands treating Se-laden agricultural tile-drainage in central California. In this field study, samples from different compartments of treatment wetlands were collected and the vegetation change in each wetland cell was examined four years after the wetland's inception. The results showed that saltgrass (Distichlis spicata) and rabbitfoot grass (Polypogon monspeliensis) were less competitive than cattail (Typha latifolia) and saltmarsh bulrush (Scirpus robustus). Over 90% of the wetland cell originally vegetated with saltgrass or rabbitfoot grass was occupied by invasive plants--i.e., when invasive species were not controlled in the wetlands. More Se was likely found in sediments from vegetated regions, compared to the unvegetated areas of the wetland cell. Particularly, rhizosphere sediments accumulated about 4-fold more Se than non-rhizosphere sediments. Among the total Se retained in the wetland 90% of the total Se was partitioned in the top 10-cm layer of sediment. The Se accumulation in plant materials accounted for about 2% of the total Se mass retained in each wetland cell. This field study demonstrated that wetland plants play significant roles in the treatment of Se-laden agricultural drainage.

  2. 76 FR 777 - National Wetland Plant List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-06

    ... Provisions of the Food Security Act. Other applications of the list include wetland restoration... taxonomy, nomenclature, distribution, and ecology of wetland flora in the U.S. In 1987, the SCS (through a... the FWS database on the NWPL, and links to botanical literature and plant ecology information...

  3. A review on removing pharmaceutical contaminants from wastewater by constructed wetlands: design, performance and mechanism.

    PubMed

    Li, Yifei; Zhu, Guibing; Ng, Wun Jern; Tan, Soon Keat

    2014-01-15

    This paper presents a comprehensive review of the current state of research activities on the application of constructed wetlands for removing pharmaceutical contaminants from wastewater. The focus of the review was placed on the application of constructed wetlands as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system. The design parameters of the reported constructed wetlands including the physical configuration, hydraulic mode, vegetation species, and targeting pharmaceuticals were summarized. The removal efficiencies of pharmaceuticals under different conditions in the wetlands were evaluated at the macroscopic level. In addition, the importance of the three main components of constructed wetlands (substrate, plants and microbes) for pharmaceutical removal was analyzed to elucidate the possible removal mechanisms involved. There is a general consensus among many researchers that constructed wetlands hold great potential of being used as an alternative secondary wastewater treatment system or as a wastewater polishing treatment system for the removal of pharmaceuticals, but relevant reported studies are scarce and are not conclusive in their findings. Current knowledge is limited on the removal efficiencies of pharmaceuticals in constructed wetlands, the removal mechanisms involved, the toxicity to constructed wetlands caused by pharmaceuticals, and the influences of certain important parameters (configuration design, hydraulic mode, temperature and seasonality, pH, oxygen and redox potential, etc.). This review promotes further research on these issues to provide more and better convincing evidences for the function and performance of larger laboratory-scale, pilot-scale or full-scale constructed wetlands.

  4. Demonstration plan for phytoremediation of explosive-contaminated groundwater in constructed wetlands at Milan Army Ammunition Plant Milan Tennessee. Volume 2. Final report

    SciTech Connect

    Behrends, L.; Sikora, F.; Kelly, D.; Coonrod, S.; Rogers, B.

    1996-01-01

    To demonstrate at Milan AAP in April 1996 through July 1997, the technical and economic feasibility of using phytoremediation in an artificial constructed wetlands for treatment of explosives-contaminated groundwater. Validated data on cost and effectiveness of this demonstration will be used to transfer this technology to the user community.

  5. Demonstration plan for phytoremediation of explosive-contaminated groundwater in constructed wetlands at Milan Army Ammunition Plant Milan Tennessee. Volume 1. Final report

    SciTech Connect

    Behrends, L.; Sikora, F.; Kelly, D.; Coonrod, S.; Rogers, B.

    1996-01-01

    To demonstrate at Milan AAP in April 1996 through July 1997, the technical and economic feasibility of using phytoremediation in an artificial, constructed wetlands for treatment of explosives-contaminated groundwater. Validated data on cost and effectiveness of this demonstration will be used to transfer this technology to the user community.

  6. HANDBOOK FOR CONSTRUCTED WETLANDS RECEIVING ACID MINE DRAINAGE

    EPA Science Inventory

    In the summer of 1987, a pilot constructed wetland was built at the Big Five Tunnel in Idaho Springs, Colorado. This report details the theory, design and construction of wetlands receiving acid mine drainages, based on the second and third year of operation of this wetland, whic...

  7. Paracetamol removal in subsurface flow constructed wetlands

    NASA Astrophysics Data System (ADS)

    Ranieri, Ezio; Verlicchi, Paola; Young, Thomas M.

    2011-07-01

    SummaryIn this study two pilot scale Horizontal Subsurface Flow Constructed Wetlands (HSFCWs) near Lecce, Italy, planted with different macrophytes ( Phragmites australis and Typha latifolia) and an unplanted control were assessed for their effectiveness in removing paracetamol. Residence time distributions (RTDs) for the two beds indicated that the Typha bed was characterized by a void volume fraction (porosity) of 0.16 and exhibited more ideal plug flow behavior (Pe = 29.7) than the Phragmites bed (Pe = 26.7), which had similar porosity. The measured hydraulic residence times in the planted beds were 35.8 and 36.7 h when the flow was equal to 1 m 3/d. The Phragmites bed exhibited a range of paracetamol removals from 51.7% for a Hydraulic Loading Rate (HLR) of 240 mm/d to 87% with 120 mm/d HLR and 99.9% with 30 mm/d. The Typha bed showed a similar behavior with percentages of removal slightly lower, ranging from 46.7% (HLR of 240 mm/d) to >99.9% (hydraulic loading rate of 30 mm/d). At the same HLR values the unplanted bed removed between 51.3% and 97.6% of the paracetamol. In all three treatments the paracetamol removal was higher with flow of 1 m 3/d and an area of approx. 7.5 m 2 (half bed) than in the case of flow equal to 0.5 m 3/d with a surface treatment of approx. 3.75 m 2. A first order model for paracetamol removal was evaluated and half lives of 5.16 to 10.2 h were obtained.

  8. CONSTRUCTED WETLANDS FOR TREATMENT OF HEAVY METALS IN URBAN STORMWATER RUNOFF: CHEMICAL SPECIATION OF WETLAND SEDIMENTS

    EPA Science Inventory

    Heavy metals in urban stormwater runoff are primarily removed by sedimentation in stormwater best management practices (BMPs) such as constructed wetlands. Heavy metals accumulated in wetland sediments may be potentially toxic to benthic invertebrates and aquatic microorganisms, ...

  9. Clay particle retention in small constructed wetlands.

    PubMed

    Braskerud, B C

    2003-09-01

    Constructed wetlands (CWs) can be used to mitigate non-point source pollution from arable fields. Previous investigations have shown that the relative soil particle retention in small CWs increases when hydraulic load increases. This paper investigates why this phenomenon occurs, even though common retention models predict the opposite, by studying clay and silt particle retention in two Norwegian CWs. Retention was measured with water flow proportional sampling systems in the inlet and outlet of the wetlands, and the texture of the suspended solids was analyzed. The surface area of the CWs was small compared to the watershed area (approximately 0.07%), giving high average hydraulic loads (1.1 and 2.0 md(-1)). One of the watersheds included only old arable land, whereas the other included areas with disturbed topsoil after artificial land leveling. Clay particle retention was 57% for the CW in the first watershed, and 22% for the CW in the disturbed watershed. The different behavior of the wetlands could be due to differences in aggregate size and stability of the particles entering the wetlands. Results showed that increased hydraulic loads did affect CW retention negatively. However, as runoff increased, soil particles/aggregates with higher sedimentation velocities entered the CWs (e.g., the clay particles behaved as silt particles). Hence, clay particle settling velocity is not constant as assumed in many prediction models. The net result was increased retention.

  10. Treatment of a sulfate-rich groundwater contaminated with perchloroethene in a hydroponic plant root mat filter and a horizontal subsurface flow constructed wetland at pilot-scale.

    PubMed

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Müller, Jochen A; Köser, Heinz

    2014-12-01

    A hydroponic plant root mat filter (HPRMF) was compared over 7months with a horizontal subsurface flow constructed wetland (HSSF CW) regarding the removal of perchloroethene (PCE) (about 2 mg L(-1)) from a sulfate- (850 mg L(-1)) and ammonia-rich (50 mg L(-1)) groundwater with a low TOC content. At a mean area specific inflow PCE load of 56 mg m(-2)d(-1), after 4m from inlet, the mean PCE removal during summer time reached 97% in the HPRMF and almost 100% in the HSSF CW. Within the first 2m in the HSSF CW metabolites like dichloroethenes, vinyl chloride and ethene accumulated, their concentrations decreased further along the flow path. Moreover, the tidal operation (a 7-d cycle) in the HSSFCW decreased the accumulation of PCE metabolites within the first 1m of the bed. The carcinogenic degradation metabolite vinyl chloride was not detected in the HPRMF. The smaller accumulation of the degradation metabolites in the HPRMF correlated with its higher redox potential. It can be concluded from this study that HPRMF appears an interesting alternative for special water treatment tasks and that tidal operation will show some positive effects on the removal of the accumulated PCE metabolites in HSSF CW.

  11. Analysis of conservative tracer measurement results using the Frechet distribution at planted horizontal subsurface flow constructed wetlands filled with coarse gravel and showing the effect of clogging processes.

    PubMed

    Dittrich, Ernő; Klincsik, Mihály

    2015-11-01

    A mathematical process, developed in Maple environment, has been successful in decreasing the error of measurement results and in the precise calculation of the moments of corrected tracer functions. It was proved that with this process, the measured tracer results of horizontal subsurface flow constructed wetlands filled with coarse gravel (HSFCW-C) can be fitted more accurately than with the conventionally used distribution functions (Gaussian, Lognormal, Fick (Inverse Gaussian) and Gamma). This statement is true only for the planted HSFCW-Cs. The analysis of unplanted HSFCW-Cs needs more research. The result of the analysis shows that the conventional solutions (completely stirred series tank reactor (CSTR) model and convection-dispersion transport (CDT) model) cannot describe these types of transport processes with sufficient accuracy. These outcomes can help in developing better process descriptions of very difficult transport processes in HSFCW-Cs. Furthermore, a new mathematical process can be developed for the calculation of real hydraulic residence time (HRT) and dispersion coefficient values. The presented method can be generalized to other kinds of hydraulic environments.

  12. Application of divided convective-dispersive transport model to simulate conservative transport processes in planted horizontal sub-surface flow constructed wetlands.

    PubMed

    Dittrich, Ernő; Klincsik, Mihály

    2015-11-01

    We have created a divided convective-dispersive transport (D-CDT) model that can be used to provide an accurate simulation of conservative transport processes in planted horizontal sub-surface flow constructed wetlands filled with coarse gravel (HSFCW-C). This model makes a fitted response curve from the sum of two independent CDT curves, which show the contributions of the main and side streams. The analytical solutions of both CDT curves are inverse Gaussian distribution functions. We used Fréchet distribution to provide a fast optimization mathematical procedure. As a result of our detailed analysis, we concluded that the most important role in the fast upward part of the tracer response curve is played by the main stream, with high porous velocity and dispersion. This gives the first inverse Gaussian distribution function. The side stream shows slower transport processes in the micro-porous system, and this shows the impact of back-mixing and dead zones, too. The significance of this new model is that it can simulate transport processes in this kind of systems more accurately than the conventionally used convective-dispersive transport (CDT) model. The calculated velocity and dispersion coefficients with the D-CDT model gave differences of 24-54% (of velocity) and 22-308% (of dispersion coeff.) from the conventional CDT model, and were closer to actual hydraulic behaviour.

  13. Environmental footprint of constructed wetlands treating wastewater.

    PubMed

    Gkika, Dimitra; Gikas, Georgios D; Tsihrintzis, Vassilios A

    2015-01-01

    The aim of the study is to determine environmentally friendlier construction materials for constructed wetland facilities treating wastewater. This is done by computing the environmental footprint of the facility based on the methodology of life cycle assessment (LCA). This methodology reveals the dominant aggravating processes during the construction of a constructed wetland (CW) and can help to create alternative environmentally friendlier solutions. This methodology was applied for the determination of the overall environmental profile of a hybrid CW facility. The LCA was applied first to the facility as originally designed, where reinforced concrete was used in some components. Then, alternative construction materials to reinforced concrete were used, such as earth covered with high density polyethylene (HDPE) or clay, and LCA was applied again. Earth structures were found to have reduced environmental impact compared to concrete ones, and clay was found environmentally friendlier compared to HDPE. Furthermore, estimation of the construction costs of the three scenarios indicate that the last scenario is also the least expensive. PMID:25837565

  14. Removal and factors influencing removal of sulfonamides and trimethoprim from domestic sewage in constructed wetlands.

    PubMed

    Dan A; Yang, Yang; Dai, Yu-nv; Chen, Chun-xing; Wang, Su-yu; Tao, Ran

    2013-10-01

    Twelve pilot-scale constructed wetlands with different configurations were set up in the field to evaluate the removal and factors that influence removal of sulfonamides (sulfadiazine, sulfapyridine, sulfacetamide, sulfamethazine and sulfamethoxazole) and trimethoprim from domestic sewage. The treatments included four flow types, three substrates, two plants and three hydraulic loading rates across two seasons (summer and winter). Most target antibiotics were efficiently removed by specific constructed wetlands; in particular, all types of constructed wetlands performed well for the degradation of sulfapyridine. Flow types were the most important influencing factor in this study, and the best removal of sulfonamides was achieved in vertical subsurface-flow constructed wetlands; however, the opposite phenomenon was found with trimethoprim. Significant relationships were observed between antibiotic degradation and higher temperature and redox potential, which indicated that microbiological pathways were the most probable degradation route for sulfonamides and trimethoprim in constructed wetlands.

  15. Treating swine wastewater by integrating earthworms into constructed wetlands.

    PubMed

    Nuengjamnong, Chackrit; Chiarawatchai, Nathasith; Polprasert, Chongrak; Otterpohl, Ralf

    2011-01-01

    The aim of this study was to investigate the application of integrating earthworms (Pheretima peguana) into two-stage pilot-scale subsurface-flow constructed wetlands (SFCWs) receiving swine wastewater in terms of their treatment performance, namely organic content, total kjeldahl nitrogen (TKN), and solid reduction as well as the quantity of sludge production. There was a minor difference in terms of removal efficiency according to each parameter when comparing the unit with earthworms to the one without earthworms. Both achieved the TKN, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total volatile suspended solids (TVSS), suspended solids (SS), and total solids (TS) removal by more than 90 %. The earthworms helped in reducing the sludge production on the surface of constructed wetlands 40 % by volume, which resulted in lowering operational costs required to empty and treat the sludge. The plant biomass production was higher in the wetlands without earthworms. Further research could be undertaken in order to effectively apply earthworms inside the wetlands.

  16. Constructed wetlands as sustainable ecotechnologies in decentralization practices: a review.

    PubMed

    Valipour, Alireza; Ahn, Young-Ho

    2016-01-01

    Recently, a range of novel and cost-effective engineered wetland technologies for decentralization practices of domestic wastewater treatment have been developed with ecological process modification, the use of functionalized plants, and advanced biofilm formation. However, selecting the one that can be more appreciated for on-site sanitation is still uncertain. This paper reviews the role of plants, media materials, microorganisms, and oxygen transfer in domestic wastewater purification through constructed wetlands (CWs). The effectiveness of traditional and recently developed CWs and the necessity of an induced biofilm attachment surface (BAS) in these systems for the treatment of domestic sewage are presented. This review also elucidates the idea of CWs for domestic wastewater characteristics highly stressed by total dissolved solids and the adaptive strategies in mitigating the cold climate impacts on their efficiencies. Further research needed to enhance the stability and sustainability of CWs is highlighted. By a more advanced investigation, BAS CWs can be specified as an ideal treatment process in decentralization.

  17. Changes in the Vegetation Cover in a Constructed Wetland at Argonne National Laboratory, Illinois

    SciTech Connect

    Bergman, C.L.; LaGory, K.

    2004-01-01

    Wetlands are valuable resources that are disappearing at an alarming rate. Land development has resulted in the destruction of wetlands for approximately 200 years. To combat this destruction, the federal government passed legislation that requires no net loss of wetlands. The United States Army Corps of Engineers (USACE) is responsible for regulating wetland disturbances. In 1991, the USACE determined that the construction of the Advanced Photon Source at Argonne National Laboratory would damage three wetlands that had a total area of one acre. Argonne was required to create a wetland of equal acreage to replace the damaged wetlands. For the first five years after this wetland was created (1992-1996), the frequency of plant species, relative cover, and water depth was closely monitored. The wetland was not monitored again until 2002. In 2003, the vegetation cover data were again collected with a similar methodology to previous years. The plant species were sampled using quadrats at randomly selected locations along transects throughout the wetland. The fifty sampling locations were monitored once in June and percent cover of each of the plant species was determined for each plot. Furthermore, the extent of standing water in the wetland was measured. In 2003, 21 species of plants were found and identified. Eleven species dominated the wetland, among which were reed canary grass (Phalaris arundinacea), crown vetch (Coronilla varia), and Canada thistle (Cirsium arvense). These species are all non-native, invasive species. In the previous year, 30 species were found in the same wetland. The common species varied from the 2002 study but still had these non-native species in common. Reed canary grass and Canada thistle both increased by more than 100% from 2002. Unfortunately, the non-native species may be contributing to the loss of biodiversity in the wetland. In the future, control measures should be taken to ensure the establishment of more desired native species.

  18. The dynamics of low-chlorinated benzenes in a pilot-scale constructed wetland and a hydroponic plant root mat treating sulfate-rich groundwater.

    PubMed

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz

    2015-03-01

    A rarely used hydroponic plant root mat filter (PRMF, of 6 m(2)) and a horizontal subsurface flow constructed wetland (HSSF CW, of 6 m(2)), operating in continuous flow and discontinuous outflow flushing modes, were investigated for treating sulfate-rich and organic carbon-lean groundwater contaminated with monochlorobenzene (MCB); 1,2-dichlorobenzene (1,2-DCB); 1,4-dichlorobenzene (1,4-DCB); and 2-chlorotoluene. Whereas the mean inflow loads ranged from 1 to 247 mg m(-2) days(-1), the range of mean inflow concentrations of the chlorobenzenes recorded over a period of 7 months was within 0.04 and 8 mg L(-1). A hydraulic surface loading rate of 30 L m(-2) days(-1) was obtained in both systems. The mean load removal efficiencies were found to vary between 87 and 93 % in the PRMF after a flow path of 4 m, while the removal efficiencies were found to range between 46 and 70 % and 71 to 73 % in the HSSF CW operating in a continuous flow mode and a discontinuous outflow flushing mode, respectively. Seasonal variations in the removal efficiencies were observed for all low-chlorinated hydrocarbons both in the PRMF and the HSSF CW, whereby the highest removal efficiencies were reached during the summer months. Sulfide formation occurred in the organic carbon-lean groundwater particularly in summer, which is probably due to the plant-derived organic carbon that fostered the microbial dissimilatory sulfate reduction. Higher redox potential in water was observed in the PRMF. In conclusion, the PRMF could be an option for the treatment of water contaminated with compounds which in particular need oxic conditions for their microbial degradation, such as in the case of low-chlorinated benzenes.

  19. [Segregation effect of purification for nitrogen and phosphate pollution in the subsurface flow constructed wetlands].

    PubMed

    Liu, Shu-Yuan; Yan, Bai-Xing; Wang, Li-Xia

    2011-03-01

    Three minitype subsurface-horizontal flow constructed wetlands planted with Calamagrostis angustifolia and Phragmites australis and filled with soil and slag were used to investigate the N, P and pH for upper layer and underlayer wetland system by intermission operation. Results demonstrated that TN removal rates in the superstratum of Calamagrostis angustifolia and Phragmites australis wetlands were 0.771 g x (m2 x d)(-1), 1.481 g x(m2 x d)(-1) with 10 days of the hydraulic retention, which were 1.15 and 1.31 times higher than that of underlayer wetland systems, respectively. Simultaneity, TP removal rates in the superstratum of Calamagrostis angustifolia and Phragmites australis wetlands were 1.655 g x (m2 x d)(-1), 6.838 g x (m2 x d)(-1), respectively, which were 1.13 and 1.28 times higher than that of underlayer wetland systems, respectively. The purification ability of upper layer in the wetland system was higher than that of underlayer. A regular trend of pH changes and upstanding buffer ability of wetland system were found. The pH values in the upper layer of soil-slag wetlands were smaller than that of underlayer which was contrary to the soil wetland. The break-point of pH curve indicates the termination of NH4(+) -N reaction in constructed wetland.

  20. Emergy evaluations for constructed wetland and conventional wastewater treatments

    NASA Astrophysics Data System (ADS)

    Zhou, J. B.; Jiang, M. M.; Chen, B.; Chen, G. Q.

    2009-04-01

    Based on emergy synthesis, this study presents a comparative study on constructed wetland (CW) and conventional wastewater treatments with three representative cases in Beijing. Accounting the environmental and economic inputs and treated wastewater output based on emergy, different characteristics of two kinds of wastewater treatments are revealed. The results show that CWs are environment-benign, less energy-intensive despite the relatively low ecological waste removal efficiency (EWRE), and less cost in construction, operation and maintenance compared with the conventional wastewater treatment plants. In addition, manifested by the emergy analysis, the cyclic activated sludge system (CASS) has the merit of higher ecological waste elimination efficiency.

  1. Possible use of constructed wetland to remove selenocyanate, arsenic, and boron from electric utility wastewater.

    PubMed

    Ye, Z H; Lin, Z-Q; Whiting, S N; de Souza, M P; Terry, N

    2003-09-01

    Wetland microcosms were used to evaluate the ability of constructed wetlands to remove extremely high concentrations of selenocyanate (SeCN-), arsenic (As), and boron (B) from wastewater generated by a coal gasification plant in Indiana. The wetland microcosms significantly reduced the concentrations of selenium (Se), As, B, and cyanide (CN) in the wastewater by 64%, 47%, 31%, and 30%, respectively. In terms of the mass of each contaminant, 79%, 67%, 57%, and 54% of the Se, As, B, and CN, respectively, loaded into the microcosms were removed from the wastewater. The primary sink for the retention of contaminants within the microcosms was the sediment, which accounted for 63%, 51%, and 36% of the Se, As, and B, respectively. Accumulation in plant tissues accounted for only 2-4%, while 3% of the Se was removed by biological volatilization to the atmosphere. Of the 14 plant species tested, cattail, Thalia, and rabbitfoot grass were highly tolerant of the contaminants and exhibited no growth retardation. Environmental toxicity testing with fathead minnow (Pimephales promelas) larvae confirmed that the water treated by the wetland microcosms was less toxic than untreated water. The data from the wetland microcosms support the view that constructed wetlands could be used to successfully reduce the toxicity of aqueous effluent contaminated with extremely high concentrations of SeCN-, As, and B, and that a pilot-scale wetland should therefore be constructed to test this in the field. Cattail, Thalia, and rabbitfoot grass would be suitable plant species to establish in such wetlands.

  2. Patterns of soil moisture and vegetation in constructed wetlands

    NASA Astrophysics Data System (ADS)

    Ursino, N.

    2009-04-01

    Early results from a new simple model for the study of eco-hydrological patterns in constructed wetland are presented. The model may simulate the case that a dominant plant tends to colonize neighbouring zones to the detriment of the other species, or that synergies between different species allow their survival under water or oxygen stress. Tasks such as of zonation and controlling invasive plants spreading by regulating water table depth and inundation timing are discussed on the base of the outcome of few numerical modelling exercises.

  3. Process-Based Modeling of Constructed Wetlands

    NASA Astrophysics Data System (ADS)

    Baechler, S.; Brovelli, A.; Rossi, L.; Barry, D. A.

    2007-12-01

    Constructed wetlands (CWs) are widespread facilities for wastewater treatment. In subsurface flow wetlands, contaminated wastewater flows through a porous matrix, where oxidation and detoxification phenomena occur. Despite the large number of working CWs, system design and optimization are still mainly based upon empirical equations or simplified first-order kinetics. This results from an incomplete understanding of the system functioning, and may in turn hinder the performance and effectiveness of the treatment process. As a result, CWs are often considered not suitable to meet high water quality-standards, or to treat water contaminated with recalcitrant anthropogenic contaminants. To date, only a limited number of detailed numerical models have been developed and successfully applied to simulate constructed wetland behavior. Among these, one of the most complete and powerful is CW2D, which is based on Hydrus2D. The aim of this work is to develop a comprehensive simulator tailored to model the functioning of horizontal flow constructed wetlands and in turn provide a reliable design and optimization tool. The model is based upon PHWAT, a general reactive transport code for saturated flow. PHWAT couples MODFLOW, MT3DMS and PHREEQC-2 using an operator-splitting approach. The use of PHREEQC to simulate reactions allows great flexibility in simulating biogeochemical processes. The biogeochemical reaction network is similar to that of CW2D, and is based on the Activated Sludge Model (ASM). Kinetic oxidation of carbon sources and nutrient transformations (nitrogen and phosphorous primarily) are modeled via Monod-type kinetic equations. Oxygen dissolution is accounted for via a first-order mass-transfer equation. While the ASM model only includes a limited number of kinetic equations, the new simulator permits incorporation of an unlimited number of both kinetic and equilibrium reactions. Changes in pH, redox potential and surface reactions can be easily incorporated

  4. Selection of a marker gene to construct a reference library for wetland plants, and the application of metabarcoding to analyze the diet of wintering herbivorous waterbirds

    PubMed Central

    Yang, Yuzhan; Zhan, Aibin; Meng, Fanjuan; Xu, Wenbin

    2016-01-01

    Food availability and diet selection are important factors influencing the abundance and distribution of wild waterbirds. In order to better understand changes in waterbird population, it is essential to figure out what they feed on. However, analyzing their diet could be difficult and inefficient using traditional methods such as microhistologic observation. Here, we addressed this gap of knowledge by investigating the diet of greater white-fronted goose Anser albifrons and bean goose Anser fabalis, which are obligate herbivores wintering in China, mostly in the Middle and Lower Yangtze River floodplain. First, we selected a suitable and high-resolution marker gene for wetland plants that these geese would consume during the wintering period. Eight candidate genes were included: rbcL, rpoC1, rpoB, matK, trnH-psbA, trnL (UAA), atpF-atpH, and psbK-psbI. The selection was performed via analysis of representative sequences from NCBI and comparison of amplification efficiency and resolution power of plant samples collected from the wintering area. The trnL gene was chosen at last with c/h primers, and a local plant reference library was constructed with this gene. Then, utilizing DNA metabarcoding, we discovered 15 food items in total from the feces of these birds. Of the 15 unique dietary sequences, 10 could be identified at specie level. As for greater white-fronted goose, 73% of sequences belonged to Poaceae spp., and 26% belonged to Carex spp. In contrast, almost all sequences of bean goose belonged to Carex spp. (99%). Using the same samples, microhistology provided consistent food composition with metabarcoding results for greater white-fronted goose, while 13% of Poaceae was recovered for bean goose. In addition, two other taxa were discovered only through microhistologic analysis. Although most of the identified taxa matched relatively well between the two methods, DNA metabarcoding gave taxonomically more detailed information. Discrepancies were likely due to

  5. Selection of a marker gene to construct a reference library for wetland plants, and the application of metabarcoding to analyze the diet of wintering herbivorous waterbirds.

    PubMed

    Yang, Yuzhan; Zhan, Aibin; Cao, Lei; Meng, Fanjuan; Xu, Wenbin

    2016-01-01

    Food availability and diet selection are important factors influencing the abundance and distribution of wild waterbirds. In order to better understand changes in waterbird population, it is essential to figure out what they feed on. However, analyzing their diet could be difficult and inefficient using traditional methods such as microhistologic observation. Here, we addressed this gap of knowledge by investigating the diet of greater white-fronted goose Anser albifrons and bean goose Anser fabalis, which are obligate herbivores wintering in China, mostly in the Middle and Lower Yangtze River floodplain. First, we selected a suitable and high-resolution marker gene for wetland plants that these geese would consume during the wintering period. Eight candidate genes were included: rbcL, rpoC1, rpoB, matK, trnH-psbA, trnL (UAA), atpF-atpH, and psbK-psbI. The selection was performed via analysis of representative sequences from NCBI and comparison of amplification efficiency and resolution power of plant samples collected from the wintering area. The trnL gene was chosen at last with c/h primers, and a local plant reference library was constructed with this gene. Then, utilizing DNA metabarcoding, we discovered 15 food items in total from the feces of these birds. Of the 15 unique dietary sequences, 10 could be identified at specie level. As for greater white-fronted goose, 73% of sequences belonged to Poaceae spp., and 26% belonged to Carex spp. In contrast, almost all sequences of bean goose belonged to Carex spp. (99%). Using the same samples, microhistology provided consistent food composition with metabarcoding results for greater white-fronted goose, while 13% of Poaceae was recovered for bean goose. In addition, two other taxa were discovered only through microhistologic analysis. Although most of the identified taxa matched relatively well between the two methods, DNA metabarcoding gave taxonomically more detailed information. Discrepancies were likely due to

  6. Selection of a marker gene to construct a reference library for wetland plants, and the application of metabarcoding to analyze the diet of wintering herbivorous waterbirds

    PubMed Central

    Yang, Yuzhan; Zhan, Aibin; Meng, Fanjuan; Xu, Wenbin

    2016-01-01

    Food availability and diet selection are important factors influencing the abundance and distribution of wild waterbirds. In order to better understand changes in waterbird population, it is essential to figure out what they feed on. However, analyzing their diet could be difficult and inefficient using traditional methods such as microhistologic observation. Here, we addressed this gap of knowledge by investigating the diet of greater white-fronted goose Anser albifrons and bean goose Anser fabalis, which are obligate herbivores wintering in China, mostly in the Middle and Lower Yangtze River floodplain. First, we selected a suitable and high-resolution marker gene for wetland plants that these geese would consume during the wintering period. Eight candidate genes were included: rbcL, rpoC1, rpoB, matK, trnH-psbA, trnL (UAA), atpF-atpH, and psbK-psbI. The selection was performed via analysis of representative sequences from NCBI and comparison of amplification efficiency and resolution power of plant samples collected from the wintering area. The trnL gene was chosen at last with c/h primers, and a local plant reference library was constructed with this gene. Then, utilizing DNA metabarcoding, we discovered 15 food items in total from the feces of these birds. Of the 15 unique dietary sequences, 10 could be identified at specie level. As for greater white-fronted goose, 73% of sequences belonged to Poaceae spp., and 26% belonged to Carex spp. In contrast, almost all sequences of bean goose belonged to Carex spp. (99%). Using the same samples, microhistology provided consistent food composition with metabarcoding results for greater white-fronted goose, while 13% of Poaceae was recovered for bean goose. In addition, two other taxa were discovered only through microhistologic analysis. Although most of the identified taxa matched relatively well between the two methods, DNA metabarcoding gave taxonomically more detailed information. Discrepancies were likely due to

  7. Vegetation effects on anammox spatial distribution and nitrogen removal in constructed wetlands treated with domestic sewage.

    PubMed

    Wang, Ling; Li, Tian

    2014-01-01

    In this study, two horizontal subsurface-flow constructed wetlands (CWs) (planted and unplanted) were constructed and compared to investigate the effects of vegetation on nitrogen removal and anammox (anaerobic ammonium oxidation) spatial distribution and enrichment. Calamus (Acorus calamus L.), which has a large root system, was selected as the vegetation. Removal of total nitrogen from the planted wetland was much higher than that from the unplanted one. Radial oxygen loss from calamus provided the planted wetland with better oxygen restoration ability, benefitting ammonium removal in the CW, especially when anammox was inhibited under winter temperatures. Enrichment of anammox bacteria in planted wetlands was much greater than that in unplanted ones. The greatest enrichment of anammox bacteria occurred in the middle layer, which had a better anaerobic environment and moderate root system. The reduced rate of metabolism in plants during winter led to a sharp decrease in anammox bacteria copy numbers in the planted wetland. Under cold temperature, the degree of enrichment with anammox bacteria in the planted wetland was similar to or slightly superior to that in the unplanted wetland.

  8. [Difference of P content in different area substrate of constructed wetland].

    PubMed

    Cao, Xue-Ying; Chong, Yun-Xiao; Yu, Guang-Wei; Zhong, Hai-Tao

    2012-11-01

    Adsorption of substrate is the main removal mechanisms of phosphorus in constructed wetland. It is easily impacted by various environmental factors existing in the wetland bed. The contents of substrate TP and the main inorganic P in different areas of both horizontal sub-surface flow constructed wetland with plant and one without plant were measured after treating wastewater five months. Different areas of the wetland with plant differed greatly in the substrate TP. Rhizosphere substrate in front area had the highest TP content and achieved 0.75 g x kg(-1), and the TP content of non-rhizosphere substrate in back area was only 0.21 g x kg(-1). The TP content of substrate in different areas of the wetland without plant had a little variety and ranged only between 0.21 and 0.27 g x kg(-1). Averagely, the substrate TP content in the wetland with plant was higher than the one in the wetland without plant. The phosphorous with Fe-bound (Fe-P), Al-bound (Al-P), and Ca-bound (Ca-P) were main inorganic phosphorous existing in the substrate in both wetlands, their contents in different areas substrate all increased, compared with the one before experiment. Fe-P and Al-P in different substrates in both wetlands had a similar variety. Their content between rhizosphere and intermediate substrate of front area in the wetland with plant and other area substrate in both wetlands differed greatly because the former increased greatly. Compared with Fe-P and Al-P, the variety of Ca-P in different substrates in both wetlands was low. But the content of Ca-P in rhizosphere substrate in wetland with plant was higher than other two parts respectively in front and back areas. Obviously, the plant root had an impact on the phosphorous content of substrate in constructed wetland. For TP, Fe-P, Al-P, Ca-P and loosely sorbed phosphorous in substrate, it increased with distance of the root.

  9. Constructed wetland as a low cost and sustainable solution for wastewater treatment adapted to rural settlements: the Chorfech wastewater treatment pilot plant.

    PubMed

    Ghrabi, Ahmed; Bousselmi, Latifa; Masi, Fabio; Regelsberger, Martin

    2011-01-01

    The paper presents the detailed design and some preliminary results obtained from a study regarding a wastewater treatment pilot plant (WWTPP), serving as a multistage constructed wetland (CW) located at the rural settlement of 'Chorfech 24' (Tunisia). The WWTPP implemented at Chorfech 24 is mainly designed as a demonstration of sustainable water management solutions (low-cost wastewater treatment), in order to prove the efficiency of these solutions working under real Tunisian conditions and ultimately allow the further spreading of the demonstrated techniques. The pilot activity also aims to help gain experience with the implemented techniques and to improve them when necessary to be recommended for wide application in rural settlements in Tunisia and similar situations worldwide. The selected WWTPP at Chorfech 24 (rural settlement of 50 houses counting 350 inhabitants) consists of one Imhoff tank for pre-treatment, and three stages in series: as first stage a horizontal subsurface flow CW system, as second stage a subsurface vertical flow CW system, and a third horizontal flow CW. The sludge of the Imhoff tank is treated in a sludge composting bed. The performances of the different components as well as the whole treatment system were presented based on 3 months monitoring. The results shown in this paper are related to carbon, nitrogen and phosphorus removal as well as to reduction of micro-organisms. The mean overall removal rates of the Chorfech WWTPP during the monitored period have been, respectively, equal to 97% for total suspended solids and biochemical oxygen demand (BOD5), 95% for chemical oxygen demand, 71% for total nitrogen and 82% for P-PO4. The removal of E. coli by the whole system is 2.5 log units.

  10. Temperature effects on wastewater nitrate removal in laboratory-scale constructed wetlands

    SciTech Connect

    Wood, S.L.; Wheeler, E.F.; Berghage, R.D.; Graves, R.E.

    1999-02-01

    Constructed wetlands may be used for removal of high nutrient loads in greenhouse wastewater prior to discharge into the environment. Temperature affects both the physical and biological activities in wetland systems. Since nitrification and denitrification are temperature-dependent processes, effluent nitrate concentrations will fluctuate due to changes in air and wetland temperature. In a cold climate, constructed wetlands can function in a temperature-controlled, greenhouse environment year-round. This work evaluates four temperature treatments on nitrate removal rates in five planted and five unplanted laboratory-scale wetlands. Wetlands were supplied with a nutrient solution similar to the fertigation runoff solution (100 PPM nitrate-N) used in greenhouse crop production. A first-order kinetic model was used to describe experimental nitrate depletion data and to predict nitrate removal rate constants (k) in the wetlands planted with Iris pseudocoras. The negligible removal in unplanted wetlands was thought to be due to lack of carbon source in the fertigation solution. Between 19 and 23 C is planted systems, k increased from 0.062 to 0.077 h{sup {minus}1}, appeared to peak around 30 C (k = 0.184 h{sup {minus}1}), but decreased at 38 C (k = 0.099h{sup {minus}1}). Based on the Arrhenius equation, k was a first-order exponential function of temperature between 18 and 30 C in planted systems. Quantification of temperature effects on planted and unplanted laboratory-scale constructed wetlands can be sued to enhance the design and management of wastewater treatment wetlands.

  11. Operating experience with constructed wetlands for wastewater treatment

    SciTech Connect

    Knight, R. )

    1993-01-01

    Constructed wetlands are treating a variety of municipal, industrial, and runoff wastewaters. The growing interest in this technology is based on 20 years of research demonstrating the beneficial effects of wetlands on water quality, particularly their ability to assimilate carbonaceous and nitrogenous wastes. Constructed wetlands are an attractive option for applications where a land-intensive, natural' treatment technology is desired and where ancillary wildlife benefits will enhance a project's overall environmental balance sheet. This paper summarizes design and operating experience from constructed wetlands representing a variety of applications, including pilot systems in place at several US pulp mills.

  12. RESPONSE OF WETLAND PLANT SPECIES TO HYDROLOGIC CONDITIONS

    EPA Science Inventory

    Understanding hydrologic requirements of native and introduced species is critical to sustaining native plant communities in wetlands of disturbed landscapes. We examined plant assemblages and 31 species from emergent wetlands in an urbanizing area of the Pacific Northwest, USA,...

  13. RESPONSE OF WETLAND PLANT SPECIES TO HYDROLOGIC CONDITIONS

    EPA Science Inventory

    Understanding hydrologic requirements of native and introduced species is critical to sustaining native plant communities in wetlands of disturbed landscapes. We examined plant assemblages and 31 species from emergent wetlands in an urbanizing area of the Pacific Northwest, USA, ...

  14. FREE-WATER DEPTH AS A MANAGEMENT TOOL FOR CONSTRUCTED WETLANDS

    EPA Science Inventory

    Marsh plants in constructed wetlands have shown the capacity to remove unwanted pollutants from storm water runoff. The plants can be established at the site from bare roots. However, plant growth from bare roots can be restricted by the elevated water depths. Using several wa...

  15. Effluent blending in constructed wetlands: Pollution prevention applications at a coal yard treatment facility

    SciTech Connect

    Carder, J.P.; Hoylman, A.M.; Sparks, B.J.

    1995-12-31

    Effluent blending, in combination with constructed wetland biotechnology, is a promising method for reducing the loading rates of pollution to receiving streams. At Oak Ridge National Laboratory, a project is underway to demonstrate this principle. An 8:2 ratio of sewage treatment plant to coal yard runoff treatment facility (CYRTF) effluent will be polished by 2 constructed wetland cells containing emergent wetland plants in saturated pea gravel at a rate of 3600 gallons per day. The relatively high concentration of nutrients in the STP effluent should stimulate biological processes leading to the reduction of chemical oxygen demand and the conversion of excess sulfate (in the CYRTF effluent) to alkalinity. Chlorine, which is added to the STP effluent to control bacteria, should also be eliminated. Measurements of wastewater toxicity, before and after the effluent blend has passed through the constructed wetlands, will be used to assess the technology`s effectiveness at reducing pollution.

  16. Designing a constructed wetland for the detention of agricultural runoff for water quality improvement.

    PubMed

    Millhollon, Eddie P; Rodrigue, Paul B; Rabb, James L; Martin, Danny F; Anderson, Russell A; Dans, Darinda R

    2009-01-01

    The goal of this study was to construct a wetland that would detain runoff from a 162-ha watershed for the purposes of improving water quality. The volume of runoff that needed to be detained was determined to be that amount coming off the 162-ha watershed consisting of 146 ha of cultivated crop land and 16 ha of pasture that exceeded the amount that would have come off of the watershed in its natural, forested state. The Soil Conservation Service (now the Natural Resource Conservation Service [NRCS]) runoff curve number method was used to estimate runoff from the watershed in its natural, forested state and in its current state of cultivated crop land and pasture. The design of the constructed wetland was accomplished using the natural topography of the wetland site and the design criteria for a sediment containment system developed by NRCS. The SPAW (Soil-Plant-Atmosphere-Water Field & Pond Hydrology) computer model was used to model depth and volume in the wetland to determine if the constructed wetland design would accommodate typical runoff events. Construction of the wetland occurred over a 4-mo period. The capabilities of the system were verified when Hurricane Rita deposited above-normal rainfall to the wetland site area. The wetland was able to accommodate this event, allowing flow through the system for 9 d, followed by continued detention of remaining runoff for water quality improvement.

  17. The use of Bassia indica for salt phytoremediation in constructed wetlands.

    PubMed

    Shelef, Oren; Gross, Amit; Rachmilevitch, Shimon

    2012-09-01

    The treatment and reuse of wastewater in constructed wetlands offers a low-cost, environmentally-friendly alternative for common engineered systems. Salinity in treated wastewater is often increased, especially in arid and semi-arid areas, and may harm crops irrigated from wetlands. We have strong evidence that halophyte plants are able to reduce the salinity of wastewater by accumulating salts in their tissues. Bassia indica is an annual halophyte with unique adaptations for salt tolerance. We performed three experiments to evaluate the capability of B. indica for salt phytoremediation as follows: a hydroponic system with mixed salt solutions, a recirculated vertical flow constructed wetland (RVFCW) with domestic wastewater, and a vertical flow constructed wetland (VFCW) for treating goat farm effluents. B. Indica plants developed successfully in all three systems and reduced the effluent salinity by 20-60% in comparison with unplanted systems or systems planted with other wetland plants. Salinity reduction was attributed to the accumulation of salts, mainly Na and K, in the leaves. Our experiments were carried out on an operative scale, suggesting a novel treatment for green desalination in constructed wetlands by salt phytoremediation in desert regions and other ecosystems.

  18. Pilot-scale constructed wetlands for tertiary treatment of refinery effluent

    SciTech Connect

    Hawkins, W.B.; Dunn, A.W.; Rodgers, J.H. Jr.; Dorn, P.B.

    1995-12-31

    Two pilot-scale wetlands were designed and constructed for tertiary treatment of refinery effluent with the goal of removing Cu, Pb, and Zn. The wetlands were built to operate in series or in parallel, with hydraulic retention times of 24 and 48 hours, respectively. The wetlands were lined with a 76 cm layer of compacted clay which is covered with a non-porous 60-mil polyethylene liner. The hydrosoil selected for use in the constructed wetlands was an alluvial sediment consisting of 74.1% sand, 25.6% silt, and 0.3% clay. Scirpus californicus (Giant Bulrush) was planted in both wetlands with an average initial plant density of 9 plants per m{sup 2} and average initial heights of 0.3 m. After six months of wetland operation, the desired design characteristics have been achieved and have aided in metal removals. The hydrosoil developed an average redox potential of {minus}170 mV and a ph of 7.0. S. californicus increased to an average density of 42 plants per m{sup 2} and grew to an average height of 2.7 m. These wetland characteristics have resulted in removals of approximately 67% of the Cu, 89% of the Pb, and 98% of the Zn from the refinery effluent in preliminary monitoring. Additional studies to evaluate operating efficiencies under different conditions are in progress.

  19. Nitrogen compounds in drain sewage after constructed wetlands.

    PubMed

    Paweska, K; Malczewska, B

    2009-01-01

    Constructed wetlands, commonly known as ground filters, are well suited mostly for wastewater treatment in areas with no central sewage system. The basic difficulty with exploitation of constructed wetlands is connected with irregular hydraulic overload of its surface. However, irregular wastewater inflow can be reduced by cyclical irrigation which increases efficiency. The unquestionable advantage of the constructed wetlands is inexpensive construction and exploitation as well as low energy consumption. The constructed wetlands also fit very well in surrounding area. The investigation concerned the analysis of two constructed wetlands which are composed of mechanical separation (septic tank) and a filter bed with subsurface flow. The research has been undertaken in a period from July to December 2008, with regard to concentration distribution of nitrogen compounds in municipal sewage after constructed wetlands. The preliminary investigation on constructed wetland which has been exploited for 10 years showed variable removal efficiency of nitrogen compounds. The continuation of the research can indicate the efficiency of wastewater treatment in summer and winter season.

  20. Constructed wetlands design for enhanced phytoremediation of effluents

    SciTech Connect

    Stewart, A.J.; Sparks, B.J.; Carder, J.P.; Sumner, J.R.

    1996-12-31

    The Oak Ridge National Laboratory (ORNL) uses constructed wetlands to solve an environmental compliance problem. Effluents from a coal yard runoff treatment facility (CYRTF) and a sewage treatment plant are both intermittently toxic based on effluent testing conducted under ORNL`s wastewater discharge permit. The CYRTF uses conventional technology (lime neutralization, flocculation); its effluent is toxic due primarily to the presence of high concentrations of calcium. Effluent from the sewage treatment plant is occasionally toxic due to a semivolatile, low-molecular weight constituent, perhaps generated when the wastewater is chlorinated prior to discharge. The two effluent are blended (about 2:8, volume:volume) before being passed through a pair of constructed wetland (CW) cells, each 1.8 m wide and 20 m long, for final equilibration. The CW system treats about 1,800 gallons of blended effluent per day. The effluent blend`s toxicity, as determined by testing with Ceriodaphnia dubia, is reduced by passage through the CW system. This simple aqueous-phase phytoremediation system is environmentally benign and provides the necessary minimal level of treatment for both effluents at low cost. We provide {open_quotes}lessons learned{close_quotes} in building and operating the CW system, and summarize the results of the chemical and toxicological tests used to demonstrate this technology`s application.

  1. Performance Evaluation of Integrated Constructed Wetland for Domestic Wastewater Treatment.

    PubMed

    Sehar, Shama; Naz, Iffat; Khan, Sumera; Naeem, Sana; Perveen, Irum; Ali, Naeem; Ahmed, Safia

    2016-03-01

    Simple, budget friendly, laboratory-scale integrated constructed wetland (ICW) was designed to assess domestic wastewater treatment performance at a loading rate of 75 mm/d, planted with native plant species: Veronica-angallis aquatica and compared with non-vegetative control system at various residence times of 4, 8, 12, 16, 20, 24, and 28 days. Results revealed that the vegetated ICW demonstrated superior performance over non-vegetated control: 69.12 vs 17.12%, 67.77 vs 16.04%, 68 vs 16.48%, 71.19 vs 6.56%, 71.54 vs 14.80%, and 72.04 vs 11.41% for total dissolved solids, total suspended solids, phosphates (PO4(-)), sulfate (SO4(-)), nitrate (NO3(-)), and nitrite (NO2(-)), respectively, at 20 days residence times. Reduction in bacterial counts (2.79 × 10(4) CFU/mL) and fecal pathogens (345.5 MPN index/100 mL) was observed in V. aquatica at 20 days residence time. Therefore, the present study highlights not only the presence of vegetation but also appropriate residence time in constructed wetlands for better performances. PMID:26931539

  2. Seafood wastewater treatment in constructed wetland: tropical case.

    PubMed

    Sohsalam, Prapa; Englande, Andrew Joseph; Sirianuntapiboon, Suntud

    2008-03-01

    A series of investigations were conducted to evaluate the feasibility of using constructed wetlands to remove pollutants from seafood processing wastewater. Six emergent plant species; Cyperus involucratus, Canna siamensis, Heliconia spp., Hymenocallis littoralis, Typha augustifolia and Thalia deabata J. Fraser were planted in surface flow wetland. They were fed with seafood wastewater that was 50% diluted with treated seafood wastewater from an aerated lagoon. All macrophytes were found to meet satisfying treatment efficiency (standard criteria for discharged wastewater) at 5 days hydraulic retention time (HRT). While C. involucratus, T. deabata and T. augustifolia met acceptable treatment efficacy at 3 days HRT. Nutrient uptake rate of these species was observed in the range of 1.43-2.30 g Nitrogen/m(2)day and 0.17-0.29 g Phosphorus/m(2)day, respectively at 3 days HRT. The highest treatment performances were found at 5 days HRT. Average removal efficiencies were 91-99% for BOD(5), 52-90% for SS, 72-92% for TN and 72-77% for TP. Plant growth and nitrogen assimilation were experienced to be most satisfactory for C. involucratus, T. deabata and T. augustifolia. Lower HRTs affected contaminant removal efficiency for all species. C. involucratus, T. deabata and T. augustifolia can remove all contaminants efficiently even at the lowest hydraulic retention time (1 day).

  3. Correlation Among Soil Enzyme Activities, Root Enzyme Activities, and Contaminant Removal in Two-Stage In Situ Constructed Wetlands Purifying Domestic Wastewater.

    PubMed

    Ni, Lixiao; Xu, Jiajun; Chu, Xianglin; Li, Shiyin; Wang, Peifang; Li, Yiping; Li, Yong; Zhu, Liang; Wang, Chao

    2016-07-01

    Two-stage in situ wetlands (two vertical flow constructed wetlands in parallel and a horizontal flow constructed wetland) were constructed for studying domestic wastewater purification and the correlations between contaminant removal and plant and soil enzyme activities. Results indicated the removal efficiency of NH4 (+) and NO3 (-) were significantly correlated with both urease and protease activity, and the removal of total phosphorus was significantly correlated with phosphatase activity. Chemical oxygen demand removal was not correlated with enzyme activity in constructed wetlands. Plant root enzyme (urease, phosphatase, protease and cellulose) activity correlation was apparent with all contaminant removal in the two vertical flow constructed wetlands. However, the correlation between the plant root enzyme activity and contaminant removal was poor in horizontal flow constructed wetlands. Results indicated that plant roots clearly played a role in the removal of contaminants. PMID:27230025

  4. Correlation Among Soil Enzyme Activities, Root Enzyme Activities, and Contaminant Removal in Two-Stage In Situ Constructed Wetlands Purifying Domestic Wastewater.

    PubMed

    Ni, Lixiao; Xu, Jiajun; Chu, Xianglin; Li, Shiyin; Wang, Peifang; Li, Yiping; Li, Yong; Zhu, Liang; Wang, Chao

    2016-07-01

    Two-stage in situ wetlands (two vertical flow constructed wetlands in parallel and a horizontal flow constructed wetland) were constructed for studying domestic wastewater purification and the correlations between contaminant removal and plant and soil enzyme activities. Results indicated the removal efficiency of NH4 (+) and NO3 (-) were significantly correlated with both urease and protease activity, and the removal of total phosphorus was significantly correlated with phosphatase activity. Chemical oxygen demand removal was not correlated with enzyme activity in constructed wetlands. Plant root enzyme (urease, phosphatase, protease and cellulose) activity correlation was apparent with all contaminant removal in the two vertical flow constructed wetlands. However, the correlation between the plant root enzyme activity and contaminant removal was poor in horizontal flow constructed wetlands. Results indicated that plant roots clearly played a role in the removal of contaminants.

  5. Indicator pathogens, organic matter and LAS detergent removal from wastewater by constructed subsurface wetlands

    PubMed Central

    2014-01-01

    Background Constructed wetland is one of the natural methods of municipal and industrial wastewater treatments with low initial costs for construction and operation as well as easy maintenance. The main objective of this study is to determine the values of indicator bacteria removal, organic matter, TSS, ammonia and nitrate affecting the wetland removal efficiency. Results The average concentration of E. coli and total coliform in the input is 1.127 × 1014 and 4.41 × 1014 MPN/100 mL that reached 5.03 × 1012 and 1.13 × 1014 MPN/100 mL by reducing 95.5% and 74.4% in wetland 2. Fecal streptococcus reached from the average 5.88 × 1014 in raw wastewater to 9.69 × 1012 in the output of wetland 2. Wetland 2 could reduce 1.5 logarithmic units of E. coli. The removal efficiency of TSS for the wetlands is 68.87%, 71.4%, 57.3%, and 66% respectively. Conclusions The overall results show that wetlands in which herbs were planted had a high removal efficiency about the indicator pathogens, organic matter, LAS detergent in comparison to a control wetland (without canes) and could improve physicochemical parameters (DO, ammonia, nitrate, electrical conductivity, and pH) of wastewater. PMID:24581277

  6. Efficiency of Constructed Wetland Vegetated with Cyperus alternifolius Applied for Municipal Wastewater Treatment

    PubMed Central

    Ebrahimi, Asghar; Taheri, Ensiyeh; Ehrampoush, Mohammad Hassan; Nasiri, Sara; Jalali, Fatemeh; Soltani, Rahele; Fatehizadeh, Ali

    2013-01-01

    The treatment of municipal wastewater from Yazd city (center of Iran) by constructed wetland vegetated with Cyperus alternifolius was assessed. Two identical wetlands with a total working volume of 60 L and 10 cm sandy layer at the bottom were used. First wetland (W1) was control and had no Cyperus alternifolius plant. Second wetland (W2) had 100 Cyperus alternifolius shrubs with 40 cm height. Influent wastewater was provided from Yazd's septic tanks effluents and after a 4-day retention time in wetlands, reactors effluent was sampled for parameters analysis. Results show that chemical oxygen demand (COD), NO3−–N, NH4+–N, and PO4−3–P in W1 were reduced to 72%, 88%, 32%, and 0.8%, and in W2, these parameters were removed in values of 83%, 81%, 47%, and 10%, respectively. In both wetlands, the highest and lowest removal efficiencies were related to COD and phosphorus, respectively. Also, the removed phosphorus can be released to stream when the soil saturated or influent phosphorus decreased and when the plant died. After a 4-day-retention time, the W2 wetland showed a statistically significantly lower COD and NH4+–N in comparison with W2 wetland. PMID:24027589

  7. Efficiency of constructed wetland vegetated with Cyperus alternifolius applied for municipal wastewater treatment.

    PubMed

    Ebrahimi, Asghar; Taheri, Ensiyeh; Ehrampoush, Mohammad Hassan; Nasiri, Sara; Jalali, Fatemeh; Soltani, Rahele; Fatehizadeh, Ali

    2013-01-01

    The treatment of municipal wastewater from Yazd city (center of Iran) by constructed wetland vegetated with Cyperus alternifolius was assessed. Two identical wetlands with a total working volume of 60 L and 10 cm sandy layer at the bottom were used. First wetland (W1) was control and had no Cyperus alternifolius plant. Second wetland (W2) had 100 Cyperus alternifolius shrubs with 40 cm height. Influent wastewater was provided from Yazd's septic tanks effluents and after a 4-day retention time in wetlands, reactors effluent was sampled for parameters analysis. Results show that chemical oxygen demand (COD), NO3 (-)-N, NH4 (+)-N, and PO4 (-3)-P in W1 were reduced to 72%, 88%, 32%, and 0.8%, and in W2, these parameters were removed in values of 83%, 81%, 47%, and 10%, respectively. In both wetlands, the highest and lowest removal efficiencies were related to COD and phosphorus, respectively. Also, the removed phosphorus can be released to stream when the soil saturated or influent phosphorus decreased and when the plant died. After a 4-day-retention time, the W2 wetland showed a statistically significantly lower COD and NH4 (+)-N in comparison with W2 wetland. PMID:24027589

  8. Microbial nitrogen transformation in constructed wetlands treating contaminated groundwater.

    PubMed

    Coban, Oksana; Kuschk, Peter; Wells, Naomi S; Strauch, Gerhard; Knoeller, Kay

    2015-09-01

    Pathways of ammonium (NH4 (+)) removal were investigated using the stable isotope approach in constructed wetlands (CWs). We investigated and compared several types of CWs: planted horizontal subsurface flow (HSSF), unplanted HSSF, and floating plant root mat (FPRM), including spatial and seasonal variations. Plant presence was the key factor influencing efficiency of NH4 (+) removal in all CWs, what was illustrated by lower NH4 (+)-N removal by the unplanted HSSF CW in comparison with planted CWs. No statistically significant differences in NH4 (+) removal efficiencies between seasons were detected. Even though plant uptake accounted for 32-100 % of NH4 (+) removal during spring and summer in planted CWs, throughout the year, most of NH4 (+) was removed via simultaneous nitrification-denitrification, what was clearly shown by linear increase of δ(15)N-NH4 (+) with decrease of loads along the flow path and absence of nitrate (NO3 (-)) accumulation. Average yearly enrichment factor for nitrification was -7.9 ‰ for planted HSSF CW and -5.8 ‰ for FPRM. Lack of enrichment for δ(15)N-NO3 (-) implied that other processes, such as nitrification and mineralization were superimposed on denitrification and makes the stable isotope approach unsuitable for the estimation of denitrification in the systems obtaining NH4 (+) rich inflow water.

  9. Effect of polyaluminium chloride on phosphorus removal in constructed wetlands treated with swine wastewater.

    PubMed

    Reddy, G B; Forbes, Dean A; Hunt, P G; Cyrus, Johnsely S

    2011-01-01

    Total phosphorus (TP) removal in aged constructed wetlands poses a challenge, especially when treated with swine wastewater with high concentrations of phosphorus (P). Our earlier studies with anaerobic lagoon swine wastewater treatment in constructed wetlands showed a decline in P removal (45-22%) with increased years of operation. These particular wetlands have been treated with swine wastewater every year since the first application in 1997. Preliminary lab-scale studies were conducted to evaluate the efficiency of polyaluminium chloride (PAC) in the removal of phosphate-P (PO4-P) from swine wastewater. The experimental objective was to increase the phosphorus treatment efficiency in constructed wetland by adding PAC as a precipitating agent. PAC was added by continuous injection to each wetland system at a rate of 3 L day(-1) (1:5 dilution of concentrated PAC). Swine wastewater was added from an anaerobic lagoon to four constructed wetland cells (11m wide x 40m long) at TP loads of 5.4-6.1 kg ha(-1) day(-1) in two experimental periods, September to November of 2008 and 2009. Treatment efficiency of two wetland systems: marsh-pond-marsh (M-P-M) and continuous marsh (CM) was compared. The wetlands were planted with cattails (Typha latifolia L.) and bulrushes (Scirpus americanus). In 2008, PAC treatment showed an increase of 27.5 and 40.8% of TP removal over control in M-P-M and CM respectively. Similar trend was also observed in the following year. PAC as a flocculant and precipitating agent showed potential to enhance TP removal in constructed wetlands treated with swine wastewater. PMID:22049722

  10. Constructed wetlands as sustainable ecotechnologies in decentralization practices: a review.

    PubMed

    Valipour, Alireza; Ahn, Young-Ho

    2016-01-01

    Recently, a range of novel and cost-effective engineered wetland technologies for decentralization practices of domestic wastewater treatment have been developed with ecological process modification, the use of functionalized plants, and advanced biofilm formation. However, selecting the one that can be more appreciated for on-site sanitation is still uncertain. This paper reviews the role of plants, media materials, microorganisms, and oxygen transfer in domestic wastewater purification through constructed wetlands (CWs). The effectiveness of traditional and recently developed CWs and the necessity of an induced biofilm attachment surface (BAS) in these systems for the treatment of domestic sewage are presented. This review also elucidates the idea of CWs for domestic wastewater characteristics highly stressed by total dissolved solids and the adaptive strategies in mitigating the cold climate impacts on their efficiencies. Further research needed to enhance the stability and sustainability of CWs is highlighted. By a more advanced investigation, BAS CWs can be specified as an ideal treatment process in decentralization. PMID:26527342

  11. Constructed wetlands for wastewater treatment: Municipal, industrial and agricultural

    SciTech Connect

    Hammer, D.A.

    1989-01-01

    A conference on constructed wetlands for waste water treatment is presented. Thirty-seven of the articles presented at the conference have been abstracted and indexed for the U.S. Department of Energy's Energy Data Base.

  12. Using constructed wetlands to treat biochemical oxygen demand and ammonia associated with a refinery effluent.

    PubMed

    Huddleston, G M; Gillespie, W B; Rodgers, J H

    2000-02-01

    This study evaluated the effectiveness of constructed wetlands for tertiary treatment of a petroleum refinery effluent. Specific performance objectives were to decrease 5-day biochemical oxygen demand (BOD(5)) and ammonia by at least 50% and to reduce toxicity associated with this effluent. Two bench-scale wetlands (replicates) were constructed in a greenhouse to provide tertiary treatment of effluent samples shipped from the refinery to the study site. Integrated wetland features included Typha latifolia Linnaeus planted in low organic (0.2%), sandy sediment, 48-h nominal hydraulic retention time, and 15-cm overlying water depth. Targeted constituents and aqueous toxicity were monitored in wetland inflows and outflows for 3 months. Following a 2 to 3-week stabilization period, effective and consistent removal of BOD(5) and ammonia (as NH(3)-N) from the effluent was observed. Average BOD(5) removal was 80%, while NH(3)-N decreased by an average of 95%. Survival of Pimephales promelas Rafinesque and Ceriodaphnia dubia Richard (7-day, static, renewal exposures) increased by more than 50% and 20%, respectively. Reproduction of C. dubia increased from zero in undiluted wetland inflow to 50% of controls in undiluted wetland outflow. This study demonstrated the potential for constructed wetlands to decrease BOD(5), ammonia, and toxicity in this refinery effluent.

  13. Assessing hydrogeochemical heterogeneity in natural and constructed wetlands

    USGS Publications Warehouse

    Hunt, R.J.; Krabbenhoft, D.P.; Anderson, M.P.

    1997-01-01

    While 'water quality function' is cited as an important wetland function to design for and preserve, we demonstrate that the scale at which hydrochemical samples are collected can significantly influence interpretations of biogeochemical processes in wetlands. Subsurface, chemical profiles for both nutrients and major ions were determined at a site in southwestern Wisconsin that contained areas of both natural and constructed wetlands. Sampling was conducted on three different scales: (1) a large scale (3 m between sampling points), (2) an intermediate scale (0.15 m between sampling points), and (3) a small scale (1.5 cm between sampling points). In most cases, significant vertical heterogeneity was observed at the 0.15 m scale, which was much larger than previously reported for freshwater wetlands and not detected by sampling water table wells screened over the same interval. However, profiles of ammonia and total phosphorus showed tenfold changes in the upper 0.2 meters of the saturated zone when sampled at the small (1.5 cm) scale, that was not depicted by sampling at the intermediate scale. At the intermediate scale of observation, one constructed wetland site differed geochemically from the natural wetlands and the other constructed wetland site due to application of off-site salvaged marsh surface and downward infiltration of rain. While important differences in dissolved inorganic phosphorus and dissolved inorganic carbon concentrations existed between the constructed wetland and the natural wetlands, we also observed substantial differences between the natural wetland sites for these constituents. A median-polishing analysis of our data showed that temporal variations in constituent concentrations within profiles, although extensively recognized in the literature, were not as important as spatial variability.

  14. Handbook for constructed wetlands receiving acid mine drainage

    SciTech Connect

    Wildeman, T.; Dietz, J.; Gusek, J.; Morea, S.

    1993-09-01

    In the summer of 1987, a pilot constructed wetland was built at the Big Five Tunnel in Idaho Springs, Colorado. The report details the theory, design and construction of wetlands receiving acid mine drainages, based on the second and third year of operation of this wetland, which was funded by the U.S. Environmental Protection Agency under the SITE Emerging Technologies Program. The text is divided into two broad sections: Part A - Theoretical Development, and Part B - Design Consideration. In the latter sections of Part A and through all of Part B the focus is on removal of metals by precipitation of sulfides through the activity of sulfate reducing bacteria.

  15. Predicting wetland plant community responses to proposed water-level-regulation plans for Lake Ontario: GIS-based modeling

    USGS Publications Warehouse

    Wilcox, D.A.; Xie, Y.

    2007-01-01

    Integrated, GIS-based, wetland predictive models were constructed to assist in predicting the responses of wetland plant communities to proposed new water-level regulation plans for Lake Ontario. The modeling exercise consisted of four major components: 1) building individual site wetland geometric models; 2) constructing generalized wetland geometric models representing specific types of wetlands (rectangle model for drowned river mouth wetlands, half ring model for open embayment wetlands, half ellipse model for protected embayment wetlands, and ellipse model for barrier beach wetlands); 3) assigning wetland plant profiles to the generalized wetland geometric models that identify associations between past flooding / dewatering events and the regulated water-level changes of a proposed water-level-regulation plan; and 4) predicting relevant proportions of wetland plant communities and the time durations during which they would be affected under proposed regulation plans. Based on this conceptual foundation, the predictive models were constructed using bathymetric and topographic wetland models and technical procedures operating on the platform of ArcGIS. An example of the model processes and outputs for the drowned river mouth wetland model using a test regulation plan illustrates the four components and, when compared against other test regulation plans, provided results that met ecological expectations. The model results were also compared to independent data collected by photointerpretation. Although data collections were not directly comparable, the predicted extent of meadow marsh in years in which photographs were taken was significantly correlated with extent of mapped meadow marsh in all but barrier beach wetlands. The predictive model for wetland plant communities provided valuable input into International Joint Commission deliberations on new regulation plans and was also incorporated into faunal predictive models used for that purpose.

  16. Feasibility of using constructed wetland treatment for molasses wastewater treatment.

    PubMed

    Sohsalam, Prapa; Sirianuntapiboon, Suntud

    2008-09-01

    The surface flow constructed wetland (SFCW) with Cyperus involucratus, Typha augustifolia and Thalia dealbata J. Fraser was applied to treat anaerobic treated-molasses wastewater (An-MWW) under the organic loading rates (OLRs) of 612, 696, 806, 929 and 1,213 kg BOD(5)ha(-1)day(-1). The results showed that both removal efficiency and plant growth rate were increased with the decrease of organic loading rate (OLR). All tested-plant species could not grow under OLR of higher than 696 kg BOD(5)mg l(-1) (p>0.05). Also, the plant-biomass of the systems was reduced by 10.4%, 26.5%, and 64.7% of initial plant-biomass under the OLR of 806, 929 and 1,213 kg BOD(5)ha(-1)day(-1), respectively. However, all tested-plant species showed the same pattern on the plant-biomass production yield and removal efficiency. The highest SS, BOD, COD, total phosphorus, NH(4)(+), NO(3)(-) and molasses pigments (MP) removal efficiencies of 90-93%, 88-89%, 67%, 70-76%, 77-82%, 94-95% and 72-77%, respectively were detected under the OLR of 612 kg BOD(5)ha(-1)day.

  17. Performance of constructed wetland treating wastewater from seafood industry.

    PubMed

    Yirong, C; Puetpaiboon, U

    2004-01-01

    Wastewater from seafood industry contains high concentrations of organic matter, nitrogen compounds, and solid matter. Constructed wetland can be used as tertiary treatment and for nutrient recycling. This research studied the performance of nitrogen and suspended solids removal efficiency of a constructed wetland treating wastewater from a seafood-processing factory located at Songkhla, southern Thailand. The existing constructed wetland has dimensions of 85 m, 352 m and 1.5 m in width, length and depth respectively, with an area of about 29,920 m2. The water depth of 0.30 m is maintained in operation with plantation of cattails (Typha augustifolia). Flow rate of influent ranged between 500-4,660 m3/d. Average hydraulic retention time in the constructed wetland was about 4.8 days. Influent and effluent from the constructed wetland were collected once a week and analyzed for pH, temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD5), Suspended solid (SS), total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH3-N), organic nitrogen (Org-N), nitrate (NO3-N), and nitrite (NO2-N). The average removal efficiencies of BOD5, SS, TKN, NH3-N, and Org-N were 84%, 94%, 49%, 52% and 82%, respectively. It was found that the constructed wetland acting as a tertiary treatment process provided additional removal of BOD5, SS and TKN from wastewater from the seafood industry.

  18. Particle retention in compact constructed wetlands treating highway stormwater.

    PubMed

    Chen, Yaoping; Park, Kisoo; Kim, Youngchul

    2014-01-01

    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. PMID:24718334

  19. 'Halophyte filters': the potential of constructed wetlands for application in saline aquaculture.

    PubMed

    De Lange, H J; Paulissen, M P C P; Slim, P A

    2013-01-01

    World consumption of seafood continues to rise, but the seas and oceans are already over-exploited. Land-based (saline) aquaculture may offer a sustainable way to meet the growing demand for fish and shellfish. A major problem of aquaculture is nutrient waste, as most of the nutrients added through feed are released into the environment in dissolved form. Wetlands are nature's water purifiers. Constructed wetlands are commonly used to treat contaminated freshwater effluent. Experience with saline systems is more limited. This paper explores the potential of constructed saline wetlands for treating the nutrient-rich discharge from land-based saline aquaculture systems. The primary function of constructed wetlands is water purification, but other ancillary benefits can also be incorporated into treatment wetland designs. Marsh vegetation enhances landscape beauty and plant diversity, and wetlands may offer habitat for fauna and recreational areas. Various approaches can be taken in utilizing plants (halophytes, macro-algae, micro-algae) in the treatment of saline aquaculture effluent. Their strengths and weaknesses are reviewed here, and a conceptual framework is presented that takes into account economic and ecological benefits as well as spatial constraints. Use of the framework is demonstrated for assessing various saline aquaculture systems in the southwestern delta region of the Netherlands.

  20. Ultraviolet disinfection of effluent from subsurface flow constructed wetlands.

    PubMed

    Richter, A Y; Weaver, R W

    2003-09-01

    Subsurface flow constructed wetlands are becoming increasingly common for on-site treatment of domestic wastewater. Before spray application, wetland effluent must be disinfected. Traditionally, tablet chlorination has been used, but an alternative is needed to increase dependability. Consequently, we investigated the use of ultraviolet light disinfection of effluent from constructed wetlands. Two low pressure (254 nm) and two medium pressure ultraviolet bulbs (190 to 400 nm) were used for disinfection. Upon installation, all units disinfected effluent successfully. After 2 weeks in operation, three of the four units did not reduce fecal coliform populations below 200 in 100 ml of effluent due to decreased light intensity from films that developed on the bulbs. One unit consistently disinfected water to populations lower than 200 in 100 ml for 1 year without maintenance. Ultraviolet disinfection, as utilized, was not consistently suitable for disinfection of effluent from subsurface flow constructed wetlands because of coatings that developed on the bulbs and blocked the light.

  1. Establishment of vegetation in constructed wetlands using biosolids and quarry fines

    SciTech Connect

    Danehy, T.P.; Zick, R.; Brenner, F.; Chmielewski, J.; Dunn, M.H.; Cooper, D.C.

    1999-07-01

    A common problem with constructing wetlands on abandoned mine sties is the lack of adequate soil needed to establish vegetation. One component of a full-scale passive treatment system built at Jennings Environmental Education Center in Brady Township, Butler County, PA addressed this issue through the development of a field trial to find an inexpensive alternative substrate for wetland plants. A simple soil recipe was followed which called for the mixing of an inorganic material with a nutrient-rich organic material. The inorganic constituent used was silt-size pond cleanings from a sand and gravel operation. The organic material used was a composted product made from exceptional-quality biosolids. Both soil components were obtained from local sources (less than 16 kilometers (12 miles) from the site) and mixed on site with a Caterpillar 963 track loader. The soil was used to construct a channel wetland 3 meters (10 feet) wide by 61 meters (200 feet) long. A seed mixture which contained 24 different wetland plant species native to western Pennsylvania was added to the substrate prior to releasing the water from the vertical flow system into the wetland. After one year, the vegetation was studied to determine the percent cover and species composition in order to document the effectiveness of this method of wetland construction. The preliminary results of this study indicate that this is an effective means to establish and sustain wetland vegetation. The addition of a fabricated substrate consisting of composted biosolids and silt can be a very effective method to establish dense and diverse vegetation in a constructed wetland.

  2. Impact of flood damage on pollutant removal efficiencies of a subtropical urban constructed wetland.

    PubMed

    Ko, Chun-Han; Chang, Fang-Chih; Lee, Tsai-Ming; Chen, Pen-Yuan; Chen, Hsin-Hsiung; Hsieh, Hwey-Lien; Guan, Chung-Yu

    2010-09-15

    Typhoons and hurricanes in subtropical/tropical regions can induce significant environmental changes (e.g., mass flooding and inundations). However, the damage to the pollutant removal efficiencies of constructed wetlands brought about by these natural disturbances has been neglected in major studies conducted in temperate climates. Therefore, this study compares the pollutant removal performance of a constructed wetland in the Danshui River Basin, before and after the system was inundated with flooding from Typhoon Krosa in 2007. The pollutant removal performance of the free water surface (FWS) constructed wetland was investigated monthly from September 2006 to April 2008. Results of the study demonstrated that this FWS wetland effectively removed 64.3% BOD, 98.9% NH(4)-N, and 39.5% Total-P before Typhoon Krosa. However, the extensive flooding caused by Typhoon Krosa swept over most of the aboveground plant community and deposited the sediment onto the bottom of each compartment. Subsequently, reduced pollutant removal efficiencies were observed. Only 37.7% BOD, 35.1% NH(4)-N, and 31.8% Total-P were removed after this event, although the flow regime was immediately restored. Comparing the water quality data for the FWS wetland before and after Typhoon Krosa revealed the immediate, quantitative damage to the pollutant removal performance caused by the typhoon's inundation. Consequently, a high-flow bypass and additional preventive measures would protect any constructed wetland in areas subject to typhoons. PMID:20656329

  3. Impact of flood damage on pollutant removal efficiencies of a subtropical urban constructed wetland.

    PubMed

    Ko, Chun-Han; Chang, Fang-Chih; Lee, Tsai-Ming; Chen, Pen-Yuan; Chen, Hsin-Hsiung; Hsieh, Hwey-Lien; Guan, Chung-Yu

    2010-09-15

    Typhoons and hurricanes in subtropical/tropical regions can induce significant environmental changes (e.g., mass flooding and inundations). However, the damage to the pollutant removal efficiencies of constructed wetlands brought about by these natural disturbances has been neglected in major studies conducted in temperate climates. Therefore, this study compares the pollutant removal performance of a constructed wetland in the Danshui River Basin, before and after the system was inundated with flooding from Typhoon Krosa in 2007. The pollutant removal performance of the free water surface (FWS) constructed wetland was investigated monthly from September 2006 to April 2008. Results of the study demonstrated that this FWS wetland effectively removed 64.3% BOD, 98.9% NH(4)-N, and 39.5% Total-P before Typhoon Krosa. However, the extensive flooding caused by Typhoon Krosa swept over most of the aboveground plant community and deposited the sediment onto the bottom of each compartment. Subsequently, reduced pollutant removal efficiencies were observed. Only 37.7% BOD, 35.1% NH(4)-N, and 31.8% Total-P were removed after this event, although the flow regime was immediately restored. Comparing the water quality data for the FWS wetland before and after Typhoon Krosa revealed the immediate, quantitative damage to the pollutant removal performance caused by the typhoon's inundation. Consequently, a high-flow bypass and additional preventive measures would protect any constructed wetland in areas subject to typhoons.

  4. Simultaneous removal of nitrate and sulfate from greenhouse wastewater by constructed wetlands.

    PubMed

    Gruyer, Nicolas; Dorais, Martine; Alsanius, Beatrix W; Zagury, Gérald J

    2013-07-01

    This study evaluated the effectiveness of C-enriched subsurface-flow constructed wetlands in reducing high concentrations of nitrate (NO) and sulfate (SO) in greenhouse wastewaters. Constructed wetlands were filled with pozzolana, planted with common cattail (), and supplemented as follows: (i) constructed wetland with sucrose (CW+S), wetland units with 2 g L of sucrose solution from week 1 to 28; (ii) constructed wetland with compost (CW+C), wetland units supplemented with a reactive mixture of compost and sawdust; (iii) constructed wetland with compost and no sucrose (CW+CNS) from week 1 to 18, and constructed wetland with compost and sucrose (CW+CS) at 2 g L from week 19 to 28; and (iv) constructed wetland (CW). During 28 wk, the wetlands received a typical reconstituted greenhouse wastewater containing 500 mg L SO and 300 mg L NO. In CW+S, CW+C, and CW+CS, appropriate C:N ratio (7:3.4) and redox potential (-53 to 39 mV) for denitrification resulted in 95 to 99% NO removal. Carbon source was not a limiting factor for denitrification in C-enriched constructed wetlands. In CW+S and CW+CS, the dissolved organic carbon (DOC)/SO ratios of 0.36 and 0.28 resulted in high sulfate-reducing bacteria (SRB) counts and high SO removal (98%), whereas low activities were observed at DOC/SO ratios of 0.02 (CW) to 0.11 (CW+C, CW+CNS). On week 19, when organic C content was increased by sucrose addition in CW+CS, SRB counts increased from 2.80 to 5.11 log[CFU+1] mL, resulting in a level similar to the one measured in CW+S (4.69 log[CFU+1] mL). Consequently, high sulfate reduction occurred after denitrification, suggesting that low DOC (38-54 mg L) was the limiting factor. In CW, DOC concentration (9-10 mg L) was too low to sustain efficient denitrification and, therefore, sulfate reduction. Furthermore, the high concentration of dissolved sulfides observed in CW+S and CW+CS treated waters were eliminated by adding FeCl.

  5. Treatments of oil-refinery and steel-mill wastewaters by mesocosm constructed wetland systems.

    PubMed

    Yang, L; Hu, C C

    2005-01-01

    In this study, two types of industrial wastewater, oil-refining and steel-milling, were selected for investigating their feasibility of treatment by mesocosm constructed wetland systems. The secondly treated effluents from the wastewater treatment plants were directly discharged into the systems controlled at different flow rates. Three wetland mesocosms were installed in the two industries: mesocosms A and B were in the oil refinery, and mesocosm C was in the steel mill. The substratum media used in wetland systems were sand (mesocosm A) and gravel (mesocosms B and C), while the vegetation types selected were reeds (mesocosms A and B) and mixed species of reeds and cattails (mesocosm C). The flow regimes were controlled as free water surface (FWS) and subsurface flow (SSF) for the sand- and gravel-beds, respectively. According to the experimental results, we found that the system treating oil-refining wastewater performed better than that treating steel-milling wastewater learned by comparing the removal efficiencies of COD, total N and total P. In addition, it was found that for oil-refining wastewater treatments, the SSF wetland system (mesocosm B) performed better than FWS (mesocosm A) wetland system when comparing both of their removal of pollutants and growth of vegetation. Besides, the effluents from these two industrial wetland treatment systems might be reclaimed and reused for boiler water, cooling, cleaning and miscellaneous purposes in industries. Further treatments are required if the constructed wetland effluents are thought about being reused for processing in industries.

  6. Wetland plant waxes from Olduvai Gorge, Tanzania

    NASA Astrophysics Data System (ADS)

    Tamalavage, A.; Magill, C. R.; Barboni, D.; Ashley, G. M.; Freeman, K. H.

    2013-12-01

    Olduvai Gorge, northern Tanzania, exposes a Plio-Pleistocene sedimentary record that includes lake and lake-margin sediments and fossil remains of ancient plants and early humans. There are rich paleontological and cultural records at Olduvai Gorge that include thousands of vertebrate fossils and stone tools. Previous studies of plant biomarkers in lake sediments from Olduvai Gorge reveal repeated, abrupt changes in landscape dominance by woodland or grassland vegetation during the early Pleistocene, about 1.8 million years ago. However, the reconstruction of wetland vegetation in the past is limited by a dearth of published lipid signatures for modern wetland species. Here, we present lipid and isotopic data for leaf tissues from eight modern plants (i.e., sedge and Typha species) living in wetlands near Olduvai Gorge. Trends in values for molecular and leaf δ13C and average chain length (ACL) of n-alkanes in plant tissues are similar to values for underlying soils. Compound-specific δ13C values for n-alkanes C25 to C33 range between -36.4 to -23.1‰ for C3 plants and -22.3 to -19.5‰ for C4 plants. Fractionation factors between leaf and lipids, ɛ29 and ɛ33, fall within the range reported in the literature, but they differ more widely within a single plant. For C3 plants, the average difference between ɛ29 and ɛ33 is 6.5 ‰, and the difference between ɛ29 and ɛ33 for C4 plants is less than 2‰. Both plant types show a parabolic relationship between chain length and δ13C values, in which C29 typically has the most depleted value, and typically shift by 3-5‰ between alkane homologs. This pattern has not been previously reported, and could be unique for sedge lipids. If so, these data help constrain the application of plant wax biomarkers from sedges for paleo-vegetation reconstruction in paleoclimate studies and at archaeological sites.

  7. Impact of elemental uptake in the root chemistry of wetland plants.

    PubMed

    Aryal, Rupak; Nirola, Ramkrishna; Beecham, Simon; Kamruzzaman, Mohammad

    2016-09-01

    Plants play a key role in the accumulation of metals in contaminated environment. Ephemeral plants, such as cyperus vaginatus, from the family Cyperaceae have been used in constructed wetlands to alter the biogeochemistry of waterlogged soils. High elemental content in wetlands often induces chemical changes in the root, stem and leaf of wetland plants. Elemental uptake and possible chemical changes in the roots of Cyperus vaginatus was investigated and compared with plants grown away from the wetland. Among the 9 heavy metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) and metalloid (As) measured, with the exception of Mn, all metals had higher content in the plant roots grown within the wetland. This was followed by plants grown near to the wetland that receive stormwater occasionally and then plants grown far from the wetland. The 3-D fluorescence spectra record showed notable differences in the chemical composition of roots grown in the three locations. The spectra combined with parallel factor analysis showed three dominant fluorescence components. Comparison of the fluorescence signatures showed a continuum of spectral properties constrained by the degree of metal contamination.

  8. Impact of elemental uptake in the root chemistry of wetland plants.

    PubMed

    Aryal, Rupak; Nirola, Ramkrishna; Beecham, Simon; Kamruzzaman, Mohammad

    2016-09-01

    Plants play a key role in the accumulation of metals in contaminated environment. Ephemeral plants, such as cyperus vaginatus, from the family Cyperaceae have been used in constructed wetlands to alter the biogeochemistry of waterlogged soils. High elemental content in wetlands often induces chemical changes in the root, stem and leaf of wetland plants. Elemental uptake and possible chemical changes in the roots of Cyperus vaginatus was investigated and compared with plants grown away from the wetland. Among the 9 heavy metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) and metalloid (As) measured, with the exception of Mn, all metals had higher content in the plant roots grown within the wetland. This was followed by plants grown near to the wetland that receive stormwater occasionally and then plants grown far from the wetland. The 3-D fluorescence spectra record showed notable differences in the chemical composition of roots grown in the three locations. The spectra combined with parallel factor analysis showed three dominant fluorescence components. Comparison of the fluorescence signatures showed a continuum of spectral properties constrained by the degree of metal contamination. PMID:26709636

  9. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    SciTech Connect

    Zellmer, S.D. ); Rastorfer, J.R. . Dept. of Biological Sciences ANL Van Dyke, G.D. . Dept. of Biology)

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs.

  10. Modeling BOD removal in constructed wetlands with mixing cell method

    SciTech Connect

    Chen, S.; Wang, G.T.; Xue, S.K.

    1999-01-01

    A new concept, transport detention time, is proposed in this paper to describe solute-transport processes. Using this concept, a new mathematical model was developed to describe biochemical oxygen demand removal in constructed wetlands. By treating a constructed wetland as a series of continuous stir tank reactors, an nth-order ordinary differential equation was derived based on the principle of mass balance and convective-dispersive equation and by introducing transfer function and Laplace transform. The number of continuous stir tank reactors of a particular wetland was determined by the parameters, such as dispersion coefficient and flow velocity, occurring in the wetland. Two examples were presented to illustrate the applications of the model. Moment method and a combination of moment and optimization methods were used to estimate the model parameters from tracer experiment data. A comparison between the model presented in this paper and the currently used plug-flow-constructed wetland model indicated that the former was more accurate. Additionally, this model can be applied to transient conditions, is theoretically sound, and represents a theoretical advance in constructed wetland research.

  11. CONSTRUCTED WETLAND TREATMENT SYSTEMS FOR WATER QUALITY IMPROVEMENT

    SciTech Connect

    Nelson, E.

    2010-07-19

    The Savannah River National Laboratory implemented a constructed wetland treatment system (CWTS) in 2000 to treat industrial discharge and stormwater from the Laboratory area. The industrial discharge volume is 3,030 m{sup 3} per day with elevated toxicity and metals (copper, zinc and mercury). The CWTS was identified as the best treatment option based on performance, capital and continuing cost, and schedule. A key factor for this natural system approach was the long-term binding capacity of heavy metals (especially copper, lead, and zinc) in the organic matter and sediments. The design required that the wetland treat the average daily discharge volume and be able to handle 83,280 m{sup 3} of stormwater runoff in a 24 hour period. The design allowed all water flow within the system to be driven entirely by gravity. The CWTS for A-01 outfall is composed of eight one-acre wetland cells connected in pairs and planted with giant bulrush to provide continuous organic matter input to the system. The retention basin was designed to hold stormwater flow and to allow controlled discharge to the wetland. The system became operational in October of 2000 and is the first wetland treatment system permitted by South Carolina DHEC for removal of metals. Because of the exceptional performance of the A-01 CWTS, the same strategy was used to improve water quality of the H-02 outfall that receives discharge and stormwater from the Tritium Area of SRS. The primary contaminants in this outfall were also copper and zinc. The design for this second system required that the wetland treat the average discharge volume of 415 m{sup 3} per day, and be able to handle 9,690 m{sup 3} of stormwater runoff in a 24 hour period. This allowed the building of a system much smaller than the A-01 CWTS. The system became operational in July 2007. Metal removal has been excellent since water flow through the treatment systems began, and performance improved with the maturation of the vegetation during

  12. Identification and modelling the HRT distribution in subsurface constructed wetland.

    PubMed

    Cui, Lijuan; Zhang, Yan; Zhang, Manyin; Li, Wei; Zhao, Xinsheng; Li, Shengnan; Wang, Yifei

    2012-11-01

    This study focused on the identification of the hydrodynamics of a horizontal subsurface constructed wetland (HSSF-CW) located in Beijing wildlife rescue and rehabilitation center, Beijing. The effects of plant growth of iris tectorum on the hydrodynamic behaviours were studied and the distribution of the hydraulic residence time was simulated by several mathematical models in order to understand the fluctuations and mixing processes of pollutants in the HSSF-CW. Treatment performance of the HSSF-CW was evaluated by comparing the area-based removal rates of different pollutants. According to the results, water depth has a negative effect on the plant growth and a larger hydraulic loading rate is not conducive to the growth of wetland plants. Modelling the probability density of the residence time distribution indicated that the shorter hydraulic residence time of 10.16 hours compared with a theoretical hydraulic residence time of 12.81 hours was responsible for the lower removal efficiency of pollutants (T-P: 0.17 ± 0.04 g m(-2) day(-1), T-N: 1.10 ± 0.05 g m(-2) day(-1), PO(4)-P: 0.08 ± 0.04 g m(-2) day(-1), NH(4)-N: 0.19 ± 0.02 g m(-2) day(-1), NO(3)-N: 0.52 ± 0.03 g m(-2) day(-1), Chl_a: 18.26 ± 0.09 g m(-2) day(-1)). The results of a superposition simulation of residence time distribution indicated that the asymmetric double sigmoidal (asym2sig) model is competent at providing a reasonable match between the measured and the predicted values to some extent. Based on the good fit of the experimental datasets by the asym2sig probability density function, the mathematical expectation approximated to the actual hydraulic residence time (10.16 hours) of the HSSF-CW.

  13. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: An ecosustainable approach

    SciTech Connect

    Rai, P.K.

    2008-07-01

    This review addresses the global problem of heavy metal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. Constructed wetlands proved to be effective for the abatement of heavy metal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some of the potent wetland plants for heavy metal removal. Biomass disposal problem and seasonal growth of aquatic macrophytes are some limitations in the transfer of phytoremediation technology from the laboratory to the field. However, the disposed biomass of macrophytes may be used for various fruitful applications. An ecosustainable model has been developed through the author's various works, which may ameliorate some of the limitations. The creation of more areas for phytoremediation may also aid in wetlands conservation. Genetic engineering and biodiversity prospecting of endangered wetland plants are important future prospects in this regard.

  14. Nitrogen detection in the vegetation of prototype constructed wetlands using chlorophyll fluorescence

    NASA Astrophysics Data System (ADS)

    Rosero, Edison; Plazas, Lucero; Solarte, Efraín; Fernández, Adrián; Peña, Enrique; Peña, Miguel

    2009-08-01

    Constructed wetlands are a very efficient, clean and economical way to remove organic contaminants from waste water. In the whole water cleaning process, some other complex processes, such as physical sedimentation, filtration, chemical precipitation, and material absorption by vegetation, are involved. The Nitrogen absorption efficiency by heliconnia psitacorumm, was studied at laboratory scale in a small reactor simulating a subsurface flow constructed wetland. Chlorophyll increasing was measured by fluorescence, using blue LED, 460 [nm] as excitation light source. Besides, spectral differences were observed in the spectral signal and in its derivative, indicating changes in the plant physiological response.

  15. Greenhouse gas emissions from constructed wetlands treating dairy wastewater

    NASA Astrophysics Data System (ADS)

    Glass, Vimy M.

    In Nova Scotia, constructed wetland systems are widely considered as effective treatment systems for agricultural wastewater. Although research has examined the water quality treatment attributes, there has been limited focus on the air quality effects of these systems. Six operational pilot-scale constructed wetlands were built with flow-through chambers for quantifying greenhouse gas (GHG) emissions in Truro, NS. Utilized within this facility were three gas analyzers to monitor GHG emissions (CO2, N 2O, CH4) and the gaseous fluxes could then be determined using the mass balance micrometeorological technique. Prior to data collection, the site underwent testing to ensure valid conclusions and replicated responses from the wetland systems. Those wetlands receiving wastewater at a typical HLR (10.6 mm d-1) and with ample vegetation displayed the best concentration reductions. During the growing season (GS), average CO 2 consumption was large (approximately -44 g CO2m -2 d-1) for wetlands with dense vegetation (approximately 100% cover) at the typical loading rate. For those wetlands at higher loading rates, CO2 emissions were observed to be as high as +9.2 g CO 2m-2 d-1. Wetlands with typical loading rates and healthy aquatic vegetation produced average CH4 fluxes of approximately 43 g CO2 eq. m-2d-1, while higher loaded systems with little vegetation approached 90 g CO 2 eq. m-2d-1. During the non-growing season (NGS), all vegetated wetlands exhibited higher CH4 emissions than the non-vegetated systems (˜15 to 20% higher). Vegetation maturity played a strong role in the GHG balance. The average CO2consumption for wetlands with established vegetation was ˜ -36 g CO2 m -2 d-1 during the GS. Wetland 4, which had been newly transplanted in 2004, had the highest single day CO2 consumption of -152 g CO2m-2 d-1 . Methane emissions from wetlands with two-year-old vegetation followed the same pattern but were approximately half of the emissions recorded from 2003. The

  16. Performance comparison of constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen removal.

    PubMed

    Tee, H C; Seng, C E; Noor, A Md; Lim, P E

    2009-05-15

    This study aims to compare the performance of planted and unplanted constructed wetlands with gravel- and raw rice husk-based media for phenol and nitrogen removal. Four laboratory-scale horizontal subsurface-flow constructed wetland units, two of which planted with cattail (Typha latifolia) were operated outdoors. The units were operated at a nominal hydraulic retention time of 7 days and fed with domestic wastewater spiked with phenol concentration at 300 mg/L for 74 days and then at 500 mg/L for 198 days. The results show that planted wetland units performed better than the unplanted ones in the removal and mineralization of phenol. This was explained by the creation of more micro-aerobic zones in the root zone of the wetland plants which allow a faster rate of phenol biodegradation, and the phenol uptake by plants. The better performance of the rice husk-based planted wetland compared to that of the gravel-based planted wetland in phenol removal could be explained by the observation that more rhizomes were established in the rice husk-based wetland unit thus creating more micro-aerobic zones for phenol degradation. The role of rice husk as an adsorbent in phenol removal was considered not of importance.

  17. Aquatic macroinvertebrates associated with Schoenoplectus litter in a constructed wetland in California (USA)

    USGS Publications Warehouse

    Nelson, S.M.; Thullen, J.S.

    2008-01-01

    Culm processing characteristics were associated with differences in invertebrate density in a study of invertebrates and senesced culm packs in a constructed treatment wetland. Invertebrate abundance differed by location within the wetland and there were differences between the two study years that appeared to be related to water quality and condition of culm material. Open areas in the wetland appeared to be critical in providing dissolved oxygen (DO) and food (plankton) to the important invertebrate culm processor, Glyptotendipes. As culm packs aged, invertebrate assemblages became less diverse and eventually supported mostly tubificid worms and leeches. It appears from this study that wetland design is vital to processing of plant material and that designs that encourage production and maintenance of high DO's will encourage microbial and invertebrate processing of material.

  18. Wetlands: Water, Wildlife, Plants, and People.

    ERIC Educational Resources Information Center

    Vandas, Steve

    1992-01-01

    Describes wetlands and explains their importance to man and ecology. Delineates the role of water in wetlands. Describes how wetlands are classified: estuarine, riverine, lacustrine, palustrine, and marine. Accompanying article is a large, color poster on wetlands. Describes an activity where metaphors are used to explore the functions of…

  19. Hydrocarbon removal in an experimental gravel bed constructed wetland.

    PubMed

    Omari, K; Revitt, M; Shutes, B; Garelick, H

    2003-01-01

    Two outdoor subsurface flow beds (control and experimental, 10 m x 1 m) were filled with a substrate of pea gravel (3-6 mm) to a depth of 60 cm. The experimental bed or small-scale constructed wetland was originally planted with Typha seedlings at a density of 7.5 plants/m2. Both beds (experimental and control) were treated with the same aqueous concentrations of diesel oil under identical dosing conditions. The average overall hydrocarbon removal efficiencies at the three monitored depths (top, middle and bottom) in the subsurface systems were 80.1 +/- 9.8%, 78.0 +/- 9.1% and 71.6 +/- 10.0% in the experimental bed and 72.3 +/- 11.9%, 69.1 +/- 10.3% and 63.4 +/- 9.4% in the control bed. The differences in the hydrocarbon removal efficiencies between corresponding months in 1999 and 2000 were statistically analysed and are generally not significant. The individual hydrocarbon removal efficiencies exceeded 60% in the top sections of both beds except for C-11 and C-25 with C-23 and C-26 also reduced in the control bed. Overall differences in the removal efficiencies of the planted and the unplanted beds as well as at different depths in both systems, indicate that Typha related removal processes complementing adsorption onto the gravel substrate are occurring.

  20. Seeking a way to promote the use of constructed wetlands for domestic wastewater treatment in developing countries.

    PubMed

    Zurita, F; Belmont, M A; De Anda, J; White, J R

    2011-01-01

    The aim of this study was to evaluate the domestic wastewater treatment efficiency as well as the survivability of commercially valuable ornamental plants in subsurface flow wetlands (SSFW) for domestic wastewater (DWW) treatment in laboratory and pilot wetland studies. The laboratory scale study included five different species (Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum, Canna hybrids and Hemmerocallis dumortieri) that were evaluated in horizontal flow subsurface treatment cells. All the plants survived during the 6-month experimental period demonstrating high wetland nutrient treatment efficiency. In order to validate and expand these preliminary results, a pilot-scale wetland study was carried out in SSFWs under two different flow regimes (horizontal and vertical flow). Four ornamental species were tested during a 1-year period: Zantedeschia aethiopica, Strelitzia reginae, Anthurium andreanum and Agapanthus africanus. The removal efficiencies were significantly higher in the vertical subsurface-flow constructed wetlands (VFCW) for all pollutants, except for nitrate (NO(3)-N), total nitrogen (TN) and total suspended solids (TSS). These results show that it is feasible to use select non-wetland plants with high market value in SSFWs without reducing the efficiency of the wastewater treatment system, although future work should continue in order to apply this technology in a large scale. The added value of floriculture in treatment wetlands can help to promote the use of constructed wetlands (CW) for domestic wastewater treatment in developing countries where economical resources are scarce and water pollution with DWW is common. PMID:21330710

  1. Pipeline Corridors through wetlands -- Impacts on plant communities: Mill Creek Tributary Crossing, Jefferson County, New York, 1992 Survey

    SciTech Connect

    Van Dyke, G.D.; Shem, L.M.; Zimmerman, R.E.

    1994-12-01

    The goal of the Gas Research Institute Wetland Corridors Program is to identify representative impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents the results of the survey July 1992, at the Mills Creek tributary crossing, Jefferson County, New York. Data were collected from three wetland communities along the 1991 pipeline and compared with predisturbance data obtained in a June 1991 survey. Within one year after pipeline installation, 50% of the soil surface of the ROW in the scrub-shrub community was covered by emergent vegetation. Average wetland values for the ROW in 1992 were lower than in 1991, indicating that the removal of woody plants resulted in a community composed of species with greater fidelity to wetlands. In the emergent marsh community after one year, the average percentage of surface covered by standing water was greater in the ROW than in the adjacent natural areas. The ROW in the forested wetland community also contained standing water, although none was found in the natural forest areas. The entire study site remains a wetland, with the majority of plant species in all sites being either obligate or facultative wetland species. Weighted and unweighted average wetland indices for each community, using all species, indicated wetland vegetation within the newly established ROW.

  2. Polar organic solvent removal in microcosm constructed wetlands.

    PubMed

    Grove, Janet Kowles; Stein, Otto R

    2005-10-01

    Three polar organic solvents, acetone, tetrahydrofuran (THF) and 1-butanol, were added at 100 mg/l each to post-primary municipal wastewater in order to simulate a mixed waste stream. This mixture was applied to an experimental microcosm subsurface constructed wetland system consisting of replicates of Juncus effusus, Carex lurida, Iris pseudacorus, Pondeteria cordata and unplanted controls in a series of 14-day batch incubations over a yearlong period simulating a summer and winter season. 90% removal of 1-butanol typically took less than 3 days. 90% removal of acetone required from 5 to 10 days in summer and 10 to 14 days in winter. 90% removal of THF required at least 10 days and was frequently not achieved during the 14-day incubations. Initial experiments confirmed that the majority of solvent removal was via microbial bioremediation. Solvent removal was typically better in planted replicates, especially Juncus, regardless of season. The removal rate of all solvents was slower in winter, but the seasonal effect was most pronounced in the unplanted control replicates and least in the Carex and Juncus replicates. Plant and seasonal effects are believed to be due, in part, to variation in metabolic pathways induced by plant and seasonal variation in available root-zone oxygen. Variation in transpiration also influenced species and seasonal effects on THF removal, but not the other more biodegradable solvents. A model based on a prediction of plant uptake of nonionic dissolved chemicals suggests that as much as 39% of the THF in solution could have been removed through plant transpiration.

  3. Effect of feeding strategies on pharmaceutical removal by subsurface flow constructed wetlands.

    PubMed

    Zhang, Dong Qing; Gersberg, Richard M; Hua, Tao; Zhu, Junfei; Nguyen, Anh Tuan; Law, Wing-Keung; Ng, Wun Jern; Tan, Soon Keat

    2012-01-01

    This study presents findings on an assessment of the effect of continuous and batch feeding strategies on the removal of selected pharmaceuticals from synthetic wastewater. Six mesocosm-scale constructed wetlands, including three horizontal subsurface flow constructed wetlands and three sand filters, were set up at the campus of Nanyang Technological University, Singapore. The findings showed that ibuprofen and diclofenac removal in the wetlands was significantly ( < 0.05) enhanced in the batch versus continuous mode. In contrast, naproxen and carbamazepine showed no significant differences ( > 0.05) in elimination under either feeding strategy. Our results also clearly showed that the presence of plants exerts a stimulatory effect on pharmaceutical removal for ibuprofen, diclofenac, and naproxen in batch and continuous mode. Estimation of the quantitative role of this stimulatory effect on pharmaceutical elimination of batch operation as compared with the effect of the presence of the higher plant alone showed that batch operation may account for 40 to 87% of the contribution conferred by the aquatic plant. The findings of this study imply that where maximal removal of pharmaceutical compounds is desired, periodic draining and filling might be the preferred operational strategy for full-scale, subsurface flow constructed wetlands.

  4. A bench-scale constructed wetland as a model to characterize benzene biodegradation processes in freshwater wetlands.

    PubMed

    Rakoczy, Jana; Remy, Benjamin; Vogt, Carsten; Richnow, Hans H

    2011-12-01

    In wetlands, a variety of biotic and abiotic processes can contribute to the removal of organic substances. Here, we used compound-specific isotope analysis (CSIA), hydrogeochemical parameters and detection of functional genes to characterize in situ biodegradation of benzene in a model constructed wetland over a period of 370 days. Despite low dissolved oxygen concentrations (<30 μM), the oxidation of ammonium to nitrate and the complete oxidation of ferrous iron pointed to a dominance of aerobic processes, suggesting efficient oxygen transfer into the sediment zone by plants. As benzene removal became highly efficient after day 231 (>98% removal), we applied CSIA to study in situ benzene degradation by indigenous microbes. Combining carbon and hydrogen isotope signatures by two-dimensional stable isotope analysis revealed that benzene was degraded aerobically, mainly via the monohydroxylation pathway. This was additionally supported by the detection of the BTEX monooxygenase gene tmoA in sediment and root samples. Calculating the extent of biodegradation from the isotope signatures demonstrated that at least 85% of benzene was degraded by this pathway and thus, only a small fraction was removed abiotically. This study shows that model wetlands can contribute to an understanding of biodegradation processes in floodplains or natural wetland systems.

  5. Higher diversity of ammonia/ammonium-oxidizing prokaryotes in constructed freshwater wetland than natural coastal marine wetland.

    PubMed

    Wang, Yong-Feng; Gu, Ji-Dong

    2013-08-01

    Anaerobic ammonium-oxidizing (anammox) bacteria, aerobic ammonia-oxidizing archaea (AOA), and ammonia-oxidizing bacteria (AOB) are three groups of ammonium/ammonia-oxidizing prokaryotes (AOPs) that are involved in the nitrogen cycle. This research compared the AOP communities in a constructed freshwater wetland with a natural coastal marine wetland in the subtropical Hong Kong. Both vegetated/rhizosphere and nonvegetated sediments were investigated to identify the effects of different macrophytes on the AOP communities. The polymerase chain reaction (PCR)-amplified gene fragments of 16S rRNA and archaeal and bacterial amoA (encoding the ammonia monooxygenase alpha subunit) were applied as molecular biomarkers to analyze the AOPs' phylogeny and diversity. Quantitative PCR was used to determine the abundances of AOPs in the sediments. The results showed that the relatively more heterogeneous freshwater wetland contained a broader range of phylotypes, higher diversity, more complex community structures, and more unevenly distributed abundances of AOPs than the coastal wetland. The effects of vegetation on the community structures of AOPs were plant-specific. The exotic Typha angustifolia affected the community structures of all AOPs and enhanced their abundances in the rhizosphere region. Both Phragmites australis and Cyperus malaccensis showed some effects on the community structures of AOB, but minimal effects on those of anammox bacteria or AOA. Kandelia obovata had almost no detectable effect on all AOPs due to their smaller size. This study suggested that the freshwater and coastal marine wetlands may have different contributions to the inorganic N removal due to the variations in AOP communities and plant types. PMID:23053083

  6. Ammonia removal in constructed wetlands receiving oil sands wastewater

    SciTech Connect

    Bishay, F.S.; Bayley, S.E.; Nix, P.G.

    1995-12-31

    Constructed wetlands are a component of the mine decommissioning and reclamation plan for Suncor Inc., Oil Sands Group, a large oil sands mining and extraction operation in northeastern Alberta, A field, pilot-scale wetlands facility was built in 1991. Over a three year period (1992--1994) the feasibility of constructed wetlands as treatment systems for various oil sands wastewater streams was assessed. Ammonia and hydrocarbons are the primary contaminants. Ammonia removal rates were estimated by measuring inputs and outputs of ammonia, changes in storage, and removal processes. These removal rates were comparable to rates in other studies indicating that the presence of hydrocarbons was not limiting ammonia removal. Nitrogen in sediments and vegetation was elevated; however, removal to sediments or vegetation did not contribute significantly to overall ammonia removal. Volatilization and denitrification were measured in situ. Although neither of these measured processes accounted for all of the ammonia removal, nitrification/denitrification was thought to be the primary removal mechanism.

  7. Conservative and reactive solute transport in constructed wetlands

    USGS Publications Warehouse

    Keefe, S.H.; Barber, L.B.; Runkel, R.L.; Ryan, J.N.; McKnight, Diane M.; Wass, R.D.

    2004-01-01

    The transport of bromide, a conservative tracer, and rhodamine WT (RWT), a photodegrading tracer, was evaluated in three wastewater-dependent wetlands near Phoenix, Arizona, using a solute transport model with transient storage. Coupled sodium bromide and RWT tracer tests were performed to establish conservative transport and reactive parameters in constructed wetlands with water losses ranging from (1) relatively impermeable (15%), (2) moderately leaky (45%), and (3) significantly leaky (76%). RWT first-order photolysis rates and sorption coefficients were determined from independent field and laboratory experiments. Individual wetland hydraulic profiles influenced the extent of transient storage interaction in stagnant water areas and consequently RWT removal. Solute mixing and transient storage interaction occurred in the impermeable wetland, resulting in 21% RWT mass loss from main channel and storage zone photolysis (10%) and sorption (11%) reactions. Advection and dispersion governed solute transport in the leaky wetland, limiting RWT photolysis removal (1.2%) and favoring main channel sorption (3.6%). The moderately leaky wetland contained islands parallel to flow, producing channel flow and minimizing RWT losses (1.6%).

  8. On the use of photothermal techniques for monitoring constructed wetlands

    NASA Astrophysics Data System (ADS)

    Gatts, C. E. N.; Faria, R. T.; Vargas, H.; Lannes, L. S.; Aragon, G. T.; Ovalle, A. R. C.

    2003-01-01

    Wetlands are a valued part of landscapes throughout the world. The steady increase of industrial facilities and disorganized urbanization processes, especially in developing countries, became a serious menace to these systems. The capability of wetlands to serve as a sink for nonpoint pollutants, particularly nutrients, is remarkable, but not limitless. For this reason, efforts to preserve them are considered a strategic issue for several countries. In addition, due to the exploding costs for sewage treatment, constructed wetlands for wastewater treatment (reed-bed systems) have been widely used under a variety of different conditions. Wetlands present unique characteristics related to biogeochemical cycles, the transport and transformation of chemicals due to interrelated physical, and chemical, and biological processes. Particularly, vegetated wetlands can act as a source for greenhouse gases through the emission of sediment-produced methane (CH4) to atmosphere. From studies concerning the behavior of Salvinia auriculata Aublet., we intend to demonstrate the potential use of photothermal techniques for monitoring gaseous emissions in wetlands.

  9. Comparison of interannual removal variation of various constructed wetland types.

    PubMed

    Hijosa-Valsero, María; Sidrach-Cardona, Ricardo; Bécares, Eloy

    2012-07-15

    Seven mesocosm-scale (1m(2)) constructed wetlands (CWs) of different configurations were operated outdoors for thirty-nine months under the same conditions to assess their ability to remove organic matter and nutrients from urban wastewaters. CWs differed in some design parameters, namely the presence of plants, the species chosen (i.e., Typha angustifolia or Phragmites australis), the flow configuration (i.e., surface flow or subsurface flow) and the presence/absence of a gravel bed. It was observed that, in general, removal efficiencies decreased with the aging of the system and that seasonality had a great influence on CWs. A comparison was made in order to figure out which kind of CW was more efficient for the removal of every pollutant in the long term. Planted systems were clearly better than unplanted systems even in winter. Efficiency differences among CWs were not extremely great, especially after a few years. However, some types of CWs were more adequate for the removal of certain pollutants. The effect of the aging on the main parameters involved in pollutant removal in CWs (temperature, pH, conductivity, dissolved oxygen concentration and redox potential) was assessed. The efficiency of CWs should not be evaluated based on short monitoring periods (1-2 years) after the start-up of the systems, but on longer periods.

  10. Performance of an innovative FWS constructed wetland in Crete, Greece.

    PubMed

    Dialynas, G; Kefalakis, N; Dialynas, M; Angelakis, A

    2002-01-01

    Pompia is an ancient name of a small community in Messara valley, which is the main agricultural area, in central Crete. The constructed wetland in Pompia is a free water surface (FWS) system, for treating the wastewater of the local community of 1,200 p.e. That wastewater treatment plant (WWTP) is a pilot plant but it is simple, safe, innovative, and environmentally friendly. The WWTP was funded by the Region of Crete. The Eastern Crete Development Organization was responsible for the design, supervision, management, and initial operation. The project was completed in August 1999, and has been under operation since then. The effluent is considered to be equivalent to tertiary treated municipal wastewater, and it will be used to irrigate olive orchards. The general sense for a visitor is that the FWS system operates like a natural marsh and a habitat of birds and wild animals. In addition, very high removal rates for BOD5, COD, TSS, TKN, TP, TC, and FC have been obtained.

  11. Wetland plant communities, Galveston Bay system. Final report

    SciTech Connect

    White, W.A.; Paine, J.G.

    1992-03-01

    The report is the culmination of a field investigation of wetland plant communities, and is one phase of the project, Trends and Status of Wetland and Aquatic Habitats of the Galveston Bay System, Texas, sponsored by the Galveston Bay National Estuary Program. For purpose of the topical report, wetlands are defined and classified in terms of more classical definitions, for example, salt, brackish, and fresh marshes, in accordance with project requirements. More than 150 sites were examined in the Galveston Bay system.

  12. Comparing the efficiency of Cyperus alternifolius and Phragmites australis in municipal wastewater treatment by subsurface constructed wetland.

    PubMed

    Shahi, Davod Hossein; Eslami, Hadi; Ehrampoosh, Mohamad Hasan; Ebrahimi, Asghar; Ghaneian, Mohamad Taghy; Ayatollah, Shirin; Mozayan, Mohamad Reza

    2013-04-15

    Nowadays, application of natural wastewater treatment systems such as wetland not only reduces economic costs and energy consumption, but also decreases environmental pollution. This study aimed to compare efficiency of Cyperus alternifolius and Phragmites australis in Municipal wastewater treatment by Subsurface Constructed Wetland Method. This is an applied-interventionnal study in which three reactors (control pilot, Cyperus alternifolius (umbrella palm) plant pilot and Phragmites australis (reed) plant pilot were designed by subsurface constructed wetland method. Then 90 samples were taken from input and output of reactors with four-day retention time. These samples were tested and finally the data were analyzed by Paired Sample Test statistical analysis. The results showed that removal efficiency of the parameters such as COD, BOD5, TSS, NO3-N, NH3-N, PO4-P, total coliform and fecal coliform was 74, 73, 84, 40, 36, 70, 33 and 38% in Cyperus alternifolius plant wetland, 44, 34, 77, 15, 0.3, 1, 17 and 26% in control wetland and 59, 54, 73, 6, 3, 10, 93 and 50 in Phragmites australis plant wetland, respectively. This reduction rate in all parameters- except fecal coliform- was statistically significant (p = 0.05). The results of this study showed that Cyperus alternifolius plant had higher efficiency in the removal of chemical parameters, whereas Phragmites australis plant had appropriate efficiency in the removal of microbiological parameters. Therefore, it can be concluded that application of these two plants can be effective in wastewater treatment.

  13. Comparing the efficiency of Cyperus alternifolius and Phragmites australis in municipal wastewater treatment by subsurface constructed wetland.

    PubMed

    Shahi, Davod Hossein; Eslami, Hadi; Ehrampoosh, Mohamad Hasan; Ebrahimi, Asghar; Ghaneian, Mohamad Taghy; Ayatollah, Shirin; Mozayan, Mohamad Reza

    2013-04-15

    Nowadays, application of natural wastewater treatment systems such as wetland not only reduces economic costs and energy consumption, but also decreases environmental pollution. This study aimed to compare efficiency of Cyperus alternifolius and Phragmites australis in Municipal wastewater treatment by Subsurface Constructed Wetland Method. This is an applied-interventionnal study in which three reactors (control pilot, Cyperus alternifolius (umbrella palm) plant pilot and Phragmites australis (reed) plant pilot were designed by subsurface constructed wetland method. Then 90 samples were taken from input and output of reactors with four-day retention time. These samples were tested and finally the data were analyzed by Paired Sample Test statistical analysis. The results showed that removal efficiency of the parameters such as COD, BOD5, TSS, NO3-N, NH3-N, PO4-P, total coliform and fecal coliform was 74, 73, 84, 40, 36, 70, 33 and 38% in Cyperus alternifolius plant wetland, 44, 34, 77, 15, 0.3, 1, 17 and 26% in control wetland and 59, 54, 73, 6, 3, 10, 93 and 50 in Phragmites australis plant wetland, respectively. This reduction rate in all parameters- except fecal coliform- was statistically significant (p = 0.05). The results of this study showed that Cyperus alternifolius plant had higher efficiency in the removal of chemical parameters, whereas Phragmites australis plant had appropriate efficiency in the removal of microbiological parameters. Therefore, it can be concluded that application of these two plants can be effective in wastewater treatment. PMID:24494519

  14. Effect of N:P ratio of influent on biomass, nutrient allocation, and recovery of Typha latifolia and Canna 'Bengal Tiger' in a laboratory-scale constructed wetland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Constructed wetlands (CWs) are an effective low-technology approach for treating agricultural, industrial, and municipal wastewater. Recovery of phosphorous by constructed wetland plants may be affected by wastewater nitrogen to phosphorous (N:P) ratios. Varying N:P ratios were supplied to Canna '...

  15. A microcosm study on remediation of explosives-contaminated groundwater using constructed wetlands.

    PubMed

    Sikora, F J; Behrends, L L; Phillips, W D; Coonrod, H S; Bailey, E; Bader, D F

    1997-11-21

    Anaerobic degradation of TNT and TNB in gravel systems was rapid and similar to removal rates in parrot feather lagoons. Planted and unplanted anaerobic gravel systems were the only treatments that provided significant reduction of RDX and HMX. Planted systems with parrot feather had no effect on removal rates of explosives in anaerobic gravel systems. Reciprocating wetlands were not effective in biodegrading RDX or HMX, but were very efficient at removing COD. A scaled-up concept for bioremediating contaminated groundwater can be envisioned with the data obtained in the current study. The effectiveness of anaerobic gravel systems indicate an anaerobic subsurface-flow constructed wetland can be established as the primary treatment for remediation with C added to the influent or step fed down the length of the wetland. Another option would be to add compost as a more permanent source of C to the gravel substrate. With time, the need for C supplementation may be reduced with the C exudates and redox lowering potential of certain plants like canarygrass (Phalaris arundinacea). As a secondary treatment, a reciprocating wetland would appear to be a logical choice to quickly remove C released in effluent waters of the anaerobic wetland.

  16. Effectiveness of mitigation measures with constructed forested wetlands in Maryland

    USGS Publications Warehouse

    Perry, M.C.

    1997-01-01

    Intensive research on six constructed forested wetlands in Central Maryland was conducted in 1993-1996 to determine success of these habitats as functional forested wetlands for wildlife. Areas studied ranged in size from 2 to 35 acres and were constructed by private companies under contract with three mitigation agencies. Adjacent natural forested wetlands were used as reference sites where similar data were collected. Based on data from the first four years of this study it appears that it will take 35-50 years before these areas have forested wetland vegetation and wildlife similar to that found on mature forested wetlands. This long-time period is based on the high mortality and slow growth of nursery-stock trees and shrubs transplanted on the areas. Mortality and slow growth resulted mostly from excessive surface water on the sites. The level of ground water did not appear to be a factor in regard to transplant mortality. Green ash was the woody transplant species that had the least mortality. Sampling of vegetative ground cover with one-meter square quadrats showed the predominance of grasses and herbs. [abridged abstract

  17. Mitigation of methane emissions from constructed farm wetlands.

    PubMed

    Pangala, Sunitha R; Reay, David S; Heal, Kate V

    2010-01-01

    Constructed wetlands are increasingly used for water pollution treatment but may also be sources of the greenhouse gas CH(4). The effect of addition of two potential inhibitors of methanogenesis - iron ochre and gypsum - on net CH(4) emissions was investigated in a constructed wetland treating farm runoff in Scotland, UK. CH(4) fluxes from three 15-m(2) wetland plots were measured between January and July 2008 in large static chambers incorporating a tunable diode laser, with application of 5tonha(-1) ochre and gypsum in May. CH(4) fluxes were also measured from control and ochre- and gypsum-treated wetland sediment cores incubated at constant and varying temperature in the laboratory. Ochre addition suppressed CH(4) emissions by 64+/-13% in the field plot and >90% in laboratory incubations compared to controls. Gypsum application of 5tonha(-1) in the field and laboratory experiments had no effect on CH(4) emissions, but application of 10tonha(-1) to a sediment core reduced CH(4) emissions by 28%. Suppression of CH(4) emissions by ochre application to sediment cores also increased with temperature; the reduction relative to the control increased from 50% at 17.5 degrees C to >90% at 27.5 degrees C. No significant changes in N removal or pH and potentially-toxic metal content of sediments as the result of inhibitor application were detected in the wetland during the study. PMID:20034652

  18. Metals Retention in Constructed Wetland Sediments

    SciTech Connect

    KNOX, ANNA

    2004-10-27

    The A-01 wetland treatment system (WTS) was designed to remove metals from the effluent at the A-01 NPDES outfall at the Savannah River Site, Aiken, SC. Sequential extraction data was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Remobilization of metals was determined by the Potentially Mobile Fraction (PMF) and metal retention by the Recalcitrant Factor (RF). The PMF, which includes water soluble, exchangeable, and oxides fractions, is the contaminant fraction that has the potential to enter into the mobile aqueous phase under changeable environmental conditions. PMF values were low for Cu, Zn and Pb (about 20 percent) and high for Fe and Mn (about 60 to 70 percent). The RF, which includes crystalline oxides, sulfides or silicates and aluminosilicates, is the ratio of strongly bound fractions to the total concentration of elements in sediment. RF values were about 80 percent for Cu, Zn and Pb, indicating high retention in the sediment and 30 percent to above 40 percent for Fe and Mn indication low retention.

  19. Evaluation of constructed wetland treatment performance for winery wastewater.

    PubMed

    Grismer, Mark E; Carr, Melanie A; Shepherd, Heather L

    2003-01-01

    Rapid expansion of wineries in rural California during the past three decades has created contamination problems related to winery wastewater treatment and disposal; however, little information is available about performance of on-site treatment systems. Here, the project objective was to determine full-scale, subsurface-flow constructed wetland retention times and treatment performance through assessment of water quality by daily sampling of total dissolved solids, pH, total suspended solids, chemical oxygen demand (COD), tannins, nitrate, ammonium, total Kjeldahl nitrogen, phosphate, sulfate, and sulfide across operating systems for winery wastewater treatment. Measurements were conducted during both the fall crush season of heavy loading and the spring following bottling and racking operations at the winery. Simple decay model coefficients for these constituents as well as COD and tannin removal efficiencies from winery wastewater in bench-scale reactors are also determined. The bench-scale study used upward-flow, inoculated attached-growth (pea-gravel substrate) reactors fed synthetic winery wastewater. Inlet and outlet tracer studies for determination of actual retention times were essential to analyses of treatment performance from an operational subsurface-flow constructed wetland that had been overloaded due to failure to install a pretreatment system for suspended solids removal. Less intensive sampling conducted at a smaller operational winery wastewater constructed wetland that had used pretreatment suspended solids removal and aeration indicated that the constructed wetlands were capable of complete organic load removal from the winery wastewater. PMID:14587952

  20. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE ITER

    EPA Science Inventory

    In Fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The e...

  1. ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE TECHNOLOGY CAPSULE

    EPA Science Inventory

    In fall 1994, anaerobic compost wetlands in both upflow and down flow configurations were constructed adjacent to and received drainage from the Burleigh tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The ...

  2. Spatial distribution of metals in the constructed wetlands.

    PubMed

    Kongroy, Porntawee; Tantemsapya, Netnapid; Lin, Ying-Feng; Jing, Shuh Ren; Wirojanagud, Wanpen

    2012-02-01

    Investigation of the spatial distribution of metals was conducted for two constructed wetlands used as tertiary treatment in Chia Nan University of Pharmacy and Science (CNU) and Metal Processing Industries (MPI) located in Tainan, Taiwan. These two distinguished sites were selected to compare the distribution of metals for constructed wetlands treating different types of wastewater. Along the distance, samples of water, sediment, and macrophytes were analyzed for metals including Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Additionally, measurements of water quality including temperature, pH, EC, ORP, DO, TSS, BOD, COD, and turbidity were performed. Results show that, at CNU, wastewater contained higher organic consititute (BOD 29.3 +/- 11.7 mg/, COD 46.7 +/- 33.6 mg/L) with low metals content. Wastewater at MPI contained low level of organic consititute (BOD 7.1 +/- 3.3 mg/L, and COD 66.0 +/- 56.5 mg/L) and higher metals content. Metals distribution of both sites showed similar results where metals in the sediments in the inlet zone have greater concentrations than other areas. The constructed wetlands can remove Cd, Cu, Ni, Pb, and Zn. However, there was no removal of Al, Cr, Fe, and Mn. A distance along the constructed wetlands had no effect on metal concentrations in macrophyte and water. PMID:22567700

  3. INVENTORY OF CONSTRUCTED WETLANDS IN THE UNITED STATES

    EPA Science Inventory

    During 1990 and 1991 the U.S. Environmental Production Agency (EPA) sponsored an effort to identify existing and planned constructed wetlands in the U.S. and to collect readily available information from operating systems. In addition to inquiries by telephone and mail, the effor...

  4. Hydrology and hydraulics of treatment wetlands constructed on drained peatlands

    NASA Astrophysics Data System (ADS)

    Postila, Heini; Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2013-04-01

    Treatment wetlands are globally used for wastewater purification purposes. In Finland, these wetlands are commonly peatland-based and are used to treat runoff from peat extraction sites and peatland forestry. Wetlands are also used for polishing municipal wastewaters and mining waters. In peat extraction the structures are usually called overland flow areas (OFAs), which are traditionally established on pristine peatlands. However, nowadays establishing of new peat extraction sites is guided to drained peatland areas due to the Finnish Peat Use Strategy, which leads difficulties to find undisturbed peatland area for OFA. Therefore treatment wetlands have had to construct also on drained peatland areas. In drained areas peat physical properties have changed due to oxidation and subsidence and the water flow pathways differs from OFAs flow patterns, which maybe have effect on purification results. Thus in the present study we aim to clarify the hydrology and hydraulic properties of treatment wetlands constructed on drained peatland areas. For this purposes, 20 treatment wetlands on drained peatland areas across Finland were detailed measured for peat hydraulic conductivity. In selected areas, runoff was continuously monitored, flow distribution at treatment areas was studied and water residence times measured with tracer tests using potassium iodide (KI). Generally, in the study areas, the ditches had been completely blocked, partly blocked e.g with peat dams or not blocked at all. The ditches were located partly parallel to the flow direction and partly perpendicular to it. The distribution of water to the wetlands has been implemented in many different ways e.g. by distribution ditch or by perforated pipes. Based on the results, in majority of the wetlands, the peat drainage has clearly affected the hydraulic properties of wetlands, but not on all sites. In more than half of the wetlands (12), the median hydraulic conductivity of peat drastically decreased at the

  5. Effect of treatment in a constructed wetland on toxicity of textile wastewater

    USGS Publications Warehouse

    Baughman, G.L.; Perkins, W.S.; Lasier, P.J.; Winger, P.V.

    2003-01-01

    Constructed wetlands for treating wastewater have proliferated in recent years and their characteristics have been studied extensively. In most cases, constructed wetlands have been used primarily for removal of nutrients and heavy metals. Extensive literature is available concerning construction and use of wetlands for treatment of wastewater. Even so, quantitative descriptions of wetland function and processes are highly empirical and difficult to extrapolate. The processes involved in removal of pollutants by wetlands are poorly understood, especially for waste streams as complex as textile effluents. The few studies conducted on treatment of textile wastewater in constructed wetlands were cited in earlier publications. Results of a two-year study of a full-scale wetland treating textile effluent are presented here. The paper describes the effects of the wetland on aquatic toxicity of the wastewater and draws conclusions about the utility and limitations of constructed wetlands for treatment of textile effluents.

  6. Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons.

    PubMed

    Al-Isawi, R H K; Sani, A; Almuktar, S A A A N; Scholz, M

    2015-01-01

    The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO₃-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO₄-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO₄-P and SS. The wetland with the largest aggregate size had the lowest mean NO₃-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO₃-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal. PMID:25812105

  7. Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons.

    PubMed

    Al-Isawi, R H K; Sani, A; Almuktar, S A A A N; Scholz, M

    2015-01-01

    The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO₃-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO₄-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO₄-P and SS. The wetland with the largest aggregate size had the lowest mean NO₃-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO₃-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal.

  8. Retention of manganese by a constructed wetland treating drainage from a coal ash disposal site

    SciTech Connect

    Kerrick, K.H.; Horner, M.

    1998-12-31

    A 3,200 m{sup 2} wetland was constructed in 1988 to treat drainage from an ash disposal site at a coal-fired electricity generating plant in western Pennsylvania. Concentrations of Fe and Mn in the drainage range from 30--80 mg/L and 10--20 mg/L, respectively. Acidity levels of 60--180 mg/L and a pH between 5--5.6 are typical. The wetland has always produced a high quality effluent with respect to Fe concentrations (usually less than 1 mg/L) and pH (about 7). Initial performance of the wetland with respect to Mn was encouraging, with reductions in Mn concentrations of over 50% being common during the first six years of operation. The system was modified in 1994 by adding limestone riprap below some dams and covering diversion dikes with limestone. These alterations were followed by a significant improvement in Mn removal by the system, with effluent concentrations seldom exceeding 1 mg/L. Seasonal observations indicate that Mn removal in the wetland slows during the winter. In laboratory studies, wetland limestone increased Mn removal rates by as much as 6--7 times. These rates exhibited a temperature optimum of 27 C. The rate at near 0 C was about one half that at 27 C and the rate fell to near zero at 43 C. This suggests that biological activity associated with the limestone is an important factor in the success of this wetland.

  9. Vertical flow constructed wetlands: kinetics of nutrient and organic matter removal.

    PubMed

    Pérez, M M; Hernández, J M; Bossens, J; Jiménez, T; Rosa, E; Tack, F

    2014-01-01

    The kinetics of organic matter and nutrient removal in a pilot vertical subsurface wetland with red ferralitic soil as substrate were evaluated. The wetland (20 m(2)) was planted with Cyperus alternifolius. The domestic wastewater that was treated in the wetland had undergone a primary treatment consisting of a septic moat and a buffer tank. From the sixth week of operation, the performance of the wetland stabilized, and a significant reduction in pollutant concentration of the effluent wastewater was obtained. Also a significant increase of dissolved oxygen (5 mg/l) was obtained. The organic matter removal efficiency was greater than 85% and the nutrient removal efficiency was greater than 75% in the vertical subsurface wetland. Nitrogen and biochemical oxygen demand (BOD) removal could be described by a first-order model. The kinetic constants were 3.64 and 3.27 d(-1) for BOD and for total nitrogen, respectively. Data on the removal of phosphorus were adapted to a second-order model. The kinetic constant was 0.96 (mg/l)(-1) d(-1). The results demonstrated the potential of vertical flow constructed wetlands to clean treated domestic wastewater before discharge into the environment. PMID:25026582

  10. Performance and cost evaluation of constructed wetland for domestic waste water treatment.

    PubMed

    Deeptha, V T; Sudarsan, J S; Baskar, G

    2015-09-01

    Root zone treatment through constructed wetlands is an engineered method of purifying wastewater. The aim of the present research was to study the potential of wetland plants Phragmites and Typha in treatment of wastewater and to compare the cost of constructed wetlands with that of conventional treatment systems. A pilot wetland unit of size 2x1x0.9 m was constructed in the campus. 3x3 rows of plants were transplanted into the pilot unit and subjected to wastewater from the hostels and other campus buildings. The raw wastewater and treated wastewater were collected periodically and tested for Total nitrogen (TN),Total Phosphorous (TP), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD). It was observed that this pilot unit reduced the concentrations of TN, TP, BOD and COD by 76, 73, 83 and 86%, respectively, on an average. Root zone system achieved standards for tertiary treatment with low operating costs, low maintenance costs, enhance the landscape, provide a natural habitat for birds, and did not emit any odour.

  11. Performance and cost evaluation of constructed wetland for domestic waste water treatment.

    PubMed

    Deeptha, V T; Sudarsan, J S; Baskar, G

    2015-09-01

    Root zone treatment through constructed wetlands is an engineered method of purifying wastewater. The aim of the present research was to study the potential of wetland plants Phragmites and Typha in treatment of wastewater and to compare the cost of constructed wetlands with that of conventional treatment systems. A pilot wetland unit of size 2x1x0.9 m was constructed in the campus. 3x3 rows of plants were transplanted into the pilot unit and subjected to wastewater from the hostels and other campus buildings. The raw wastewater and treated wastewater were collected periodically and tested for Total nitrogen (TN),Total Phosphorous (TP), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD). It was observed that this pilot unit reduced the concentrations of TN, TP, BOD and COD by 76, 73, 83 and 86%, respectively, on an average. Root zone system achieved standards for tertiary treatment with low operating costs, low maintenance costs, enhance the landscape, provide a natural habitat for birds, and did not emit any odour. PMID:26521546

  12. The effect of heavy metals on nitrogen and oxygen demand removal in constructed wetlands.

    PubMed

    Lim, P E; Tay, M G; Mak, K Y; Mohamed, N

    2003-01-01

    The objective of this study is to investigate the respective effects of Zn, Pb and Cd as well as the combined effect of Zn, Pb, Cd and Cu on the removal of nitrogen and oxygen demand in constructed wetlands. Four laboratory-scale gravel-filled subsurface-flow constructed wetland units planted with cattails (Typha latifolia) were operated outdoors and fed with primary-treated domestic wastewater at a constant flow rate of 25 ml/min. After 6 months, three of the wetland units were fed with the same type of wastewater spiked with Zn(II), Pb(II) and Cd(II), respectively, at 20, 5 and 1 mg/l for a further 9 months. The remaining unit was fed with the same type of wastewater spiked with a combination of Zn(II), Pb(II), Cd(II) and Cu(II) at concentrations of 10, 2.5, 0.5 and 5 mg/l, respectively, over the same period. The chemical oxygen demand (COD) and ammoniacal nitrogen (AN) concentrations were monitored at the inlet, outlet and three additional locations along the length of the wetland units to assess the performance of the wetland units at various metal loadings. At the end of the study, all cattail plants were harvested for the determination of total Kjeldahl nitrogen and metal concentrations. The results showed that the COD removal efficiency was practically independent of increasing metal loading or a combination of metal loadings during the duration of the study. In contrast, the AN removal efficiency deteriorated progressively with increasing metal loading. The relative effect of the heavy metals was found to increase in the order: Znplants as indicated by lower nitrogen uptake rates in comparison to rates recorded in wetland systems treating domestic wastewater only.

  13. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: an ecosustainable approach.

    PubMed

    Rai, Prabhat Kumar

    2008-01-01

    This review addresses the global problem of heavymetal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. Heavymetal contamination in aquatic ecosystems due to discharge of industrial effluents may pose a serious threat to human health. Alkaline precipitation, ion exchange columns, electrochemical removal, filtration, and membrane technologies are the currently available technologies for heavy metal removal. These conventional technologies are not economical and may produce adverse impacts on aquatic ecosystems. Phytoremediation of metals is a cost-effective "green" technology based on the use of specially selected metal-accumulating plants to remove toxic metals from soils and water. Wetland plants are important tools for heavy metal removal. The Ramsar convention, one of the earlier modern global conservation treaties, was adopted at Ramsar, Iran, in 1971 and became effective in 1975. This convention emphasized the wise use of wetlands and their resources. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. The extensive rhizosphere of wetland plants provides an enriched culture zone for the microbes involved in degradation. The wetland sediment zone provides reducing conditions that are conducive to the metal removal pathway. Constructed wetlands proved to be effective for the abatement of heavymetal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some

  14. Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean–Orinoco Piedmont of Colombia?

    PubMed Central

    Murillo-Pacheco, Johanna I.; Rös, Matthias; Castro-Lima, Francisco; Verdú, José R.; López-Iborra, Germán M.

    2016-01-01

    Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean–Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and (2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha), with a small area of surrounding forest (10 ± 8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account. PMID:27602263

  15. Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean-Orinoco Piedmont of Colombia?

    PubMed

    Murillo-Pacheco, Johanna I; Rös, Matthias; Escobar, Federico; Castro-Lima, Francisco; Verdú, José R; López-Iborra, Germán M

    2016-01-01

    Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean-Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and (2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha), with a small area of surrounding forest (10 ± 8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account.

  16. Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean–Orinoco Piedmont of Colombia?

    PubMed Central

    Murillo-Pacheco, Johanna I.; Rös, Matthias; Castro-Lima, Francisco; Verdú, José R.; López-Iborra, Germán M.

    2016-01-01

    Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean–Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and (2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha), with a small area of surrounding forest (10 ± 8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account.

  17. Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean-Orinoco Piedmont of Colombia?

    PubMed

    Murillo-Pacheco, Johanna I; Rös, Matthias; Escobar, Federico; Castro-Lima, Francisco; Verdú, José R; López-Iborra, Germán M

    2016-01-01

    Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean-Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and (2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha), with a small area of surrounding forest (10 ± 8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account. PMID:27602263

  18. The effect of low temperatures on ammonia removal in a laboratory-scale constructed wetland

    SciTech Connect

    Lee, M.A.; Stansbury, J.S.; Zhang, T.C.

    1999-05-01

    The effect of low temperatures on ammonia removal in constructed wetlands was studied by running a synthetic wastewater through a model, laboratory-scale gravel-filled constructed wetland (in which no plants were grown). The wetland was operated at temperatures of 5, 11.5, 15, and 23 C in an environmentally controlled chamber. An influent ammonia concentration of 45 mg/L as nitrogen was used to simulate typical domestic wastewater. For temperatures of 5, 11.5, 15, and 23 C, the wetland model achieved ammonia removal and nitrification of 45, 44, 56, and 65%, respectively. Thus, over the 18 C temperature range ammonia-nitrogen removal and nitrification rates varied only 20%. There was a net decrease in nitrogen as water passed through the wetland; this could be the result of cell growth or denitrification. Measurements were taken at the inlet, outlet, and four additional locations along the length of the reactor. Measurements were also taken at three different depths. Along the length of the reactor, nearly all nitrification was achieved in the first half of the reactor, then stopped because of low dissolved oxygen concentrations. Nitrification occurred slightly faster at the top of the reactor than at the bottom.

  19. Iron and manganese diagenesis in constructed wetlands receiving mine drainage

    SciTech Connect

    Tarutis, W.J. Jr.

    1993-01-01

    The chemical diagenesis of iron and manganese was studied in two constructed wetlands receiving coal mine drainage and in laboratory wetland mesocosms exposed to synthetic acidic mine waters, and the release of soluble metals from natural and synthetic metal oxides of differing crystallinity was studied in laboratory incubations in the presence and absence of bacterial sulfate reduction. Soil chemical characterization indicated that the formation of potentially reducible, oxide-bound precipitates accounted for the majority of iron and manganese removed in the two wetlands studied. Depth profiles revealed diagenetic remobilization of iron and manganese to the soil interstitial water due to the reductive dissolution of oxidized metals initially deposited on the wetland surface. Sulfate reduction and pyrite formation contributed little to metal removal due to organic carbon limitation in the subsurface soils. Iron and manganese in synthetic acidic mine water added to anoxic wetland mesocosms acted synergistically with respect to metal removal. The inclusion of sulfate in synthetic mine water caused a slightly greater, but statistically significant, iron removal in mesocosms relative to mesocosms not receiving sulfate. Sulfate addition had no effect on manganese removal. Iron was much more reactive than manganese towards sulfide in laboratory incubations in which sulfate reduction was allowed to occur. Liberation of iron and manganese in the absence of sulfate reduction decreased with increasing crystallinity of each metal oxide tested and was attributed to higher activation energies characteristic of a surface-reaction-controlled dissolution mechanisms.

  20. Constructed wetlands as green tools for management of boron mine wastewater.

    PubMed

    Türker, Onur Can; Türe, Cengiz; Böcük, Harun; Yakar, Anil

    2014-01-01

    Constructed wetlands are of increasing interest worldwide given that they represent an eco-technological solution to many environmental problems such as wastewater treatment. Turkey possesses approximately 70% of the world's total boron (B) reserves, and B contamination occurs in both natural and cultivated sites throughout Turkey, particularly in the north-west of the country. This study analyzes B removal and plant uptake of B in pilot plots of subsurface horizontal-flow constructed wetlands. Constructed wetlands were vegetated with Typha latifolia (referred to as CW1) and Phragmites australis (referred to as CW2) to treat wastewater from a borax reserve in Turkey--the largest of its type in the world and were assessed under field conditions. The B concentrations of water inflows to the systems were determined to be 10.2, 28.2, 84.6, 232.3, 716.4, and 2019.1 mg l(-1). The T. latifolia in the CW1 treatment group absorbed a total of 1300 mg kg(-1) B, whereas P. australis absorbed 839 mg kg(-1). As a result, CW1 had an average removal efficiency of 40.7%, while that of CW2 was 27.2%. Our results suggest that constructed wetlands are an effective, economic and eco-friendly solution to treating B mine wastewater and controlling the adverse environmental effects of B mining.

  1. Constructed wetlands as green tools for management of boron mine wastewater.

    PubMed

    Türker, Onur Can; Türe, Cengiz; Böcük, Harun; Yakar, Anil

    2014-01-01

    Constructed wetlands are of increasing interest worldwide given that they represent an eco-technological solution to many environmental problems such as wastewater treatment. Turkey possesses approximately 70% of the world's total boron (B) reserves, and B contamination occurs in both natural and cultivated sites throughout Turkey, particularly in the north-west of the country. This study analyzes B removal and plant uptake of B in pilot plots of subsurface horizontal-flow constructed wetlands. Constructed wetlands were vegetated with Typha latifolia (referred to as CW1) and Phragmites australis (referred to as CW2) to treat wastewater from a borax reserve in Turkey--the largest of its type in the world and were assessed under field conditions. The B concentrations of water inflows to the systems were determined to be 10.2, 28.2, 84.6, 232.3, 716.4, and 2019.1 mg l(-1). The T. latifolia in the CW1 treatment group absorbed a total of 1300 mg kg(-1) B, whereas P. australis absorbed 839 mg kg(-1). As a result, CW1 had an average removal efficiency of 40.7%, while that of CW2 was 27.2%. Our results suggest that constructed wetlands are an effective, economic and eco-friendly solution to treating B mine wastewater and controlling the adverse environmental effects of B mining. PMID:24912241

  2. Reuse of constructed wetland effluents for irrigation of energy crops.

    PubMed

    Barbagallo, S; Barbera, A C; Cirelli, G L; Milani, M; Toscano, A

    2014-01-01

    The aim of this study was to evaluate biomass production of promising 'no-food' energy crops, Vetiveria zizanoides (L.) Nash, Miscanthus × giganteus Greef et Deu. and Arundo donax (L.), irrigated with low quality water at different evapotranspiration restitutions. Two horizontal subsurface flow (H-SSF) constructed wetland (CW) beds, with different operation life (12 and 6 years), were used to treat secondary municipal wastewaters for crop irrigation. Water chemical, physical and microbiological parameters as well as plant bio-agronomic characters were evaluated. The results confirm the high reliability of CWs for tertiary wastewater treatment given that the H-SSF1 treatment capacity remained largely unchanged after 12 years of operation. Average total suspended solids, chemical oxygen demand and total nitrogen removal for CWs were about 68, 58 and 71%, respectively. The Escherichia coli removal was satisfactory, about 3.3 log unit for both CW beds on average, but caution should be taken as this parameter did not achieve the restrictive Italian law limits for wastewater reuse. The average above-ground dry matter productions were 7 t ha⁻¹ for Vetiveria zizanoides, 24 t ha⁻¹ for Miscanthus × giganteus and 50 t ha⁻¹ for Arundo donax. These results highlight attractive biomass yield by using treated wastewater for irrigation with a complete restitution of evapotranspiration losses. PMID:25401309

  3. Performance of constructed wetland system for public water supply.

    PubMed

    Elias, J M; Salati Filho, E; Salati, E

    2001-01-01

    The project is being conducted in the town of Analândia, São Paulo, Brazil. The constructed wetlands system for water supply consists of a channel with floating aquatic macrophytes, HDS system (Water Decontamination with Soil-Patent PI 850.3030), chlorinating system, filtering system and distribution. The project objectives include investigating the process variables to further optimize design and operation factors, evaluating the relation of nutrients and plants development, biomass production, shoot development, nutrient cycling and total and fecal coliforms removal, comparing the treatment efficiency among the seasons of the year; and moreover to compare the average values obtained between February and June 1998 (Salati et al., 1998) with the average obtained for the same parameters between March and June 2000. Studies have been developed in order to verify during one year the drinking quality of the water for the following parameters: turbidity, color, pH, dissolved oxygen, total of dissolved solids, COD, chloride, among others, according to the Ministry of Health's Regulation 36. This system of water supply projected to treat 15 L s(-1) has been in continuous operation for 2 years, it was implemented with support of the National Environment Fund (FNMA), administered by the Center of Environmental Studies (CEA-UNESP), while the technical supervision and design were performed by the Institute of Applied Ecology. The actual research project is being supported by FAPESP.

  4. Reuse of constructed wetland effluents for irrigation of energy crops.

    PubMed

    Barbagallo, S; Barbera, A C; Cirelli, G L; Milani, M; Toscano, A

    2014-01-01

    The aim of this study was to evaluate biomass production of promising 'no-food' energy crops, Vetiveria zizanoides (L.) Nash, Miscanthus × giganteus Greef et Deu. and Arundo donax (L.), irrigated with low quality water at different evapotranspiration restitutions. Two horizontal subsurface flow (H-SSF) constructed wetland (CW) beds, with different operation life (12 and 6 years), were used to treat secondary municipal wastewaters for crop irrigation. Water chemical, physical and microbiological parameters as well as plant bio-agronomic characters were evaluated. The results confirm the high reliability of CWs for tertiary wastewater treatment given that the H-SSF1 treatment capacity remained largely unchanged after 12 years of operation. Average total suspended solids, chemical oxygen demand and total nitrogen removal for CWs were about 68, 58 and 71%, respectively. The Escherichia coli removal was satisfactory, about 3.3 log unit for both CW beds on average, but caution should be taken as this parameter did not achieve the restrictive Italian law limits for wastewater reuse. The average above-ground dry matter productions were 7 t ha⁻¹ for Vetiveria zizanoides, 24 t ha⁻¹ for Miscanthus × giganteus and 50 t ha⁻¹ for Arundo donax. These results highlight attractive biomass yield by using treated wastewater for irrigation with a complete restitution of evapotranspiration losses.

  5. Enhanced degradation of textile effluent in constructed wetland system using Typha domingensis and textile effluent-degrading endophytic bacteria.

    PubMed

    Shehzadi, Maryam; Afzal, Muhammad; Khan, Muhammad Umar; Islam, Ejazul; Mobin, Amina; Anwar, Samina; Khan, Qaiser Mahmood

    2014-07-01

    Textile effluent is one of the main contributors of water pollution and it adversely affects fauna and flora. Constructed wetland is a promising approach to remediate the industrial effluent. The detoxification of industrial effluent in a constructed wetland system may be enhanced by applying beneficial bacteria that are able to degrade contaminants present in industrial effluent. The aim of this study was to evaluate the influence of inoculation of textile effluent-degrading endophytic bacteria on the detoxification of textile effluent in a vertical flow constructed wetland reactor. A wetland plant, Typha domingensis, was vegetated in reactor and inoculated with two endophytic bacterial strains, Microbacterium arborescens TYSI04 and Bacillus pumilus PIRI30. These strains possessed textile effluent-degrading and plant growth-promoting activities. Results indicated that bacterial inoculation improved plant growth, textile effluent degradation and mutagenicity reduction and were correlated with the population of textile effluent-degrading bacteria in the rhizosphere and endosphere of T. domingensis. Bacterial inoculation enhanced textile effluent-degrading bacterial population in rhizosphere, root and shoot of T. domingensis. Significant reductions in COD (79%), BOD (77%) TDS (59%) and TSS (27%) were observed by the combined use of plants and bacteria within 72 h. The resultant effluent meets the wastewater discharge standards of Pakistan and can be discharged into the environment without any risks. This study revealed that the combined use of plant and endophytic bacteria is one of the approaches to enhance textile effluent degradation in a constructed wetland system. PMID:24755300

  6. On-site wastewater treatment using subsurface flow constructed wetlands in Ireland.

    PubMed

    Gill, Laurence W; O'Luanaigh, Niall; Johnston, Paul M

    2011-01-01

    The results from an Irish EPA-funded project on the effectiveness of using constructed wetlands for treating wastewater from single households is presented, which has contributed to the design guidelines included in the new EPA Code of Practice. Three subsurface flow gravel-filled wetlands were constructed on separate sites--one to provide secondary treatment and the other two to provide tertiary treatment stages for the domestic effluent. A comprehensive analysis over three years was then conducted to provide a robust characterization of the internal dynamics of the systems, particularly with respect to N and P removal as well as evaluating the temporal water balance across the different seasons. The removal of Total N was only 29% and 30% in the secondary and tertiary treatment wetlands, respectively; particularly disappointing for the tertiary treatment process, which was receiving nitrified effluent. Studies on the (15)N stable isotope confirmed that 35% of the ammonium from the septic tank was passing straight through the process without taking part in any biogeochemical processes. However, influent N in the wetlands was shown to be biologically assimilated into organic nitrogen and then released again as soluble ammonium--so-called nitrogen "spiraling." Removal of Total P in the wetlands averaged from 28% to 45% with higher P removals measured during summer periods, although the effluent concentrations were still found to be high (> 5 mg/l on average). The phosphorus in the plant material was also analysed revealing that the annual above-ground stem matter only accounted for 1.3% to 8.4% of the annual total P-load in the wetlands. Finally, the water balance analyses showed that the mean flow discharging from both the secondary and tertiary treatment wetlands was slightly greater than the mean flow to the reed bed over the trial period, with rainfall acting to increase flows by 13% and 5%, respectively, on average in winter while just about balancing

  7. EPS solubilization treatment by applying the biosurfactant rhamnolipid to reduce clogging in constructed wetlands.

    PubMed

    Du, Mingpu; Xu, Dong; Trinh, Xuantung; Liu, Shuangyuan; Wang, Mei; Zhang, Yi; Wu, Junmei; Zhou, Qiaohong; Wu, Zhenbin

    2016-10-01

    Application of extracellular polymeric substances (EPS) solubilization treatment with biosurfactant rhamnolipid (RL) to reduce clogging in constructed wetlands was first conducted in this study. The results showed significant improvement in the solubilization and dispersion of clogging matter following the treatment. And RL dosage of 0.09-0.15g/L altered microbial group make-up and had an overall positive effect on the growth of microorganisms. Moreover, RL was found to enhance EPS dissolution and dispersion, which was beneficial for the release of enzymes embedded in the EPS, and resulted in enhanced pollutant removal. The treatment had no apparent detrimental effect on wetland plants. Our results indicate that the optimum dosage of RL is 0.12g/L, and that the approach provides a promising and moderate option to reverse wetland clogging through RL-mediated solubilization treatment. PMID:27428300

  8. EPS solubilization treatment by applying the biosurfactant rhamnolipid to reduce clogging in constructed wetlands.

    PubMed

    Du, Mingpu; Xu, Dong; Trinh, Xuantung; Liu, Shuangyuan; Wang, Mei; Zhang, Yi; Wu, Junmei; Zhou, Qiaohong; Wu, Zhenbin

    2016-10-01

    Application of extracellular polymeric substances (EPS) solubilization treatment with biosurfactant rhamnolipid (RL) to reduce clogging in constructed wetlands was first conducted in this study. The results showed significant improvement in the solubilization and dispersion of clogging matter following the treatment. And RL dosage of 0.09-0.15g/L altered microbial group make-up and had an overall positive effect on the growth of microorganisms. Moreover, RL was found to enhance EPS dissolution and dispersion, which was beneficial for the release of enzymes embedded in the EPS, and resulted in enhanced pollutant removal. The treatment had no apparent detrimental effect on wetland plants. Our results indicate that the optimum dosage of RL is 0.12g/L, and that the approach provides a promising and moderate option to reverse wetland clogging through RL-mediated solubilization treatment.

  9. Suitability of macrophytes for nutrient removal from surface flow constructed wetlands receiving secondary treated sewage effluent in Queensland, Australia.

    PubMed

    Greenway, M

    2003-01-01

    From a botanical perspective the major difference between waste stabilisation ponds and wetlands is the dominance of algae or floating plants in the former and emergent plants in the latter. Algae, floating and submerged plants remove nutrients directly from the water column whereas emergent species remove nutrients from the sediment. Water depth is a crucial factor in determining which plant types will become established. Surface flow constructed wetlands offer the greatest potential to grow a wide variety of different types of macrophytes. In assessing the suitability of plant species for nutrient removal, consideration must be given not only to nutrient uptake for growth but also storage of nutrients as plant biomass. A survey of macrophytes in 15 surface flow constructed wetlands treating secondary effluent was conducted in Queensland; 63 native species and 14 introduced species were found. Emergent species have been able to tolerate deeper water than in their natural environment and permanent waterlogging. All species grew well in the higher nutrient enriched wastewater. Submerged, floating leaved-attached and free floating species had the highest tissue nutrient content, followed by aquatic creepers. All these species remove nutrients from the water column. Emergent species had lower nutrient content but a greater biomass and were therefore able to store more nutrients per unit area of wetland. In order to maximise the efficiency of constructed wetlands for nutrient removal, a range of species should be used. Native species should be selected in preference to introduced/exotic species. PMID:14510202

  10. Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Optimization of wetland substrates and hydraulic loading.

    PubMed

    Chen, Jun; Wei, Xiao-Dong; Liu, You-Sheng; Ying, Guang-Guo; Liu, Shuang-Shuang; He, Liang-Ying; Su, Hao-Chang; Hu, Li-Xin; Chen, Fan-Rong; Yang, Yong-Qiang

    2016-09-15

    This study aimed to assess removal potential of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale horizontal subsurface-flow constructed wetlands (CWs) planted Cyperus alternifolius L. with different design parameters. Twelve CWs with three hydraulic loading rates (HLR 10, 20 and 30cm/day) and four substrates (oyster shell, zeolite, medical stone and ceramic) were set up in order to select the best optimized wetland. The result showed that 7 target antibiotics compounds including erythromycin-H2O, lincomycin, monensin, ofloxacin, sulfamerazine, sulfamethazine and novobiocin were detected, and all selected 18 genes (three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), three quinolone resistance genes (qnrB, qnrD and qnrS) and four chloramphenicol resistance genes (cmlA, fexA, fexB and floR)) and two integrase genes (int1 and int2) were positively detected in the domestic wastewaters. The aqueous removal rates of the total antibiotics ranged from17.9 to 98.5%, while those for the total ARGs varied between 50.0 and 85.8% by the mesocosm-scale CWs. After considering their aqueous removal rates in combination with their mass removals, the CW with zeolite as the substrate and HLR of 20cm/day was selected as the best choice. Combined chemical and biological analyses indicate that both microbial degradation and physical sorption processes were responsible for the fate of antibiotics and ARGs in the wetlands. The findings from this study suggest constructed wetlands could be a promising technology for the removal of emerging contaminants such as antibiotics and ARGs in domestic wastewater.

  11. Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Optimization of wetland substrates and hydraulic loading.

    PubMed

    Chen, Jun; Wei, Xiao-Dong; Liu, You-Sheng; Ying, Guang-Guo; Liu, Shuang-Shuang; He, Liang-Ying; Su, Hao-Chang; Hu, Li-Xin; Chen, Fan-Rong; Yang, Yong-Qiang

    2016-09-15

    This study aimed to assess removal potential of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale horizontal subsurface-flow constructed wetlands (CWs) planted Cyperus alternifolius L. with different design parameters. Twelve CWs with three hydraulic loading rates (HLR 10, 20 and 30cm/day) and four substrates (oyster shell, zeolite, medical stone and ceramic) were set up in order to select the best optimized wetland. The result showed that 7 target antibiotics compounds including erythromycin-H2O, lincomycin, monensin, ofloxacin, sulfamerazine, sulfamethazine and novobiocin were detected, and all selected 18 genes (three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), three quinolone resistance genes (qnrB, qnrD and qnrS) and four chloramphenicol resistance genes (cmlA, fexA, fexB and floR)) and two integrase genes (int1 and int2) were positively detected in the domestic wastewaters. The aqueous removal rates of the total antibiotics ranged from17.9 to 98.5%, while those for the total ARGs varied between 50.0 and 85.8% by the mesocosm-scale CWs. After considering their aqueous removal rates in combination with their mass removals, the CW with zeolite as the substrate and HLR of 20cm/day was selected as the best choice. Combined chemical and biological analyses indicate that both microbial degradation and physical sorption processes were responsible for the fate of antibiotics and ARGs in the wetlands. The findings from this study suggest constructed wetlands could be a promising technology for the removal of emerging contaminants such as antibiotics and ARGs in domestic wastewater. PMID:27173842

  12. Investigations of subsurface flow constructed wetlands and associated geomaterial resources in the Akumal and Reforma regions, Quintana Roo, Mexico

    NASA Astrophysics Data System (ADS)

    Krekeler, Mark P. S.; Probst, Pete; Samsonov, Misha; Tselepis, Cynthia M.; Bates, William; Kearns, Lance E.; Maynard, J. Barry

    2007-12-01

    Subsurface flow constructed wetlands in the village of Akumal, Quintana Roo, Mexico were surveyed to determine the general status of the wetland systems and provide baseline information for long term monitoring and further study. Twenty subsurface flow wetlands were surveyed and common problems observed in the systems were overloading, poor plant cover, odor, and no secondary containment. Bulk mineral composition of aggregate from two subsurface flow constructed wetlands was determined to consist solely of calcite using bulk powder X-ray diffraction. Some soil structure is developed in the aggregate and aggregate levels in wetlands drop at an estimated rate between 3 and 10 cm/year for overloaded wetlands owing to dissolution. Mineral composition from fresh aggregate samples commonly is a mixture of calcite and aragonite. Trace amounts of Pb, Zn, Co, and Cr were observed in fresh aggregate. Coefficients of permeability ( k) varied from 0.006 to 0.027 cm/s with an average values being 0.016 cm/s. Grain size analysis of fresh aggregate samples indicates there are unimodal and multimodal size distributions in the samples with modes in the coarse and fine sand being common. Investigations of other geologic media from the Reforma region indicate that a dolomite with minor amounts of Fe-oxide and palygorskite is abundant and may be a better aggregate source that the current materials used. A Ca-montmorillonite bed was identified in the Reforma region as well and this unit is suitable to serve as a clay liner to prevent leaks for new and existing wetland systems. These newly discovered geologic resources should aid in the improvement of subsurface flow constructed wetlands in the region. Although problems do exist in these wetlands with respect to design, these systems represent a successful implementation of constructed wetlands at a community level in developing regions.

  13. Biological mechanisms associated with triazophos (TAP) removal by horizontal subsurface flow constructed wetlands (HSFCW).

    PubMed

    Wu, Juan; Feng, Yuqin; Dai, Yanran; Cui, Naxin; Anderson, Bruce; Cheng, Shuiping

    2016-05-15

    Triazophos (TAP) is a widely used pesticide that is easily accumulated in the environment due to its relatively high stability: this accumulation from agricultural runoff results in potential hazards to aquatic ecosystems. Constructed wetlands are generally considered to be an effective technology for treating TAP polluted surface water. However, knowledge about the biological mechanisms of TAP removal is still lacking. This study investigates the responses of a wetland plant (Canna indica), substrate enzymes and microbial communities in bench-scale horizontal subsurface-flow constructed wetlands (HSCWs) loaded with different TAP concentrations (0, 0.1, 0.5 and 5 mg · L(-1)). The results indicate that TAP stimulated the activities of superoxide dismutase (SOD) and peroxidase (POD) in the roots of C. indica. The highest TAP concentrations significantly inhibited photosynthetic activities, as shown by a reduced effective quantum yield of PS II (ΦPS II) and lower electron transport rates (ETR). However, interestingly, the lower TAP loadings exhibited some favorable effects on these two variables, suggesting that C. indica is a suitable species for use in wetlands designed for treatment of low TAP concentrations. Urease and alkaline phosphatase (ALP) in the wetland substrate were activated by TAP. Two-way ANOVA demonstrated that urease activity was influenced by both the TAP concentrations and season, while acidphosphatase (ACP) only responded to seasonal variations. Analysis of high throughput sequencing of 16S rRNA revealed seasonal variations in the microbial community structure of the wetland substrate at the phylum and family levels. In addition, urease activity had a greater correlation with the relative abundance of some functional microbial groups, such as the Bacillaceae family, and the ALP and ACP may be influenced by the plant more than substrate microbial communities.

  14. Subtropical reservoir shorelines have reduced plant species and functional richness compared with adjacent riparian wetlands

    NASA Astrophysics Data System (ADS)

    Liu, Wenzhi; Liu, Guihua; Liu, Hui; Song, Yu; Zhang, Quanfa

    2013-12-01

    Dam construction has large negative effects on biodiversity in river and riparian ecosystems worldwide. This study aimed to determine whether reservoir shorelines had lower plant species diversity and functional diversity than unregulated or lightly regulated riparian wetlands and to examine the responses of plant diversity and functional traits to reservoir shoreline environmental gradients. We surveyed 146, 44, and 67 plots on reservoir shorelines and in mainstem and tributary riparian wetlands, respectively, in a subtropical river-reservoir system. Species richness, functional richness, evenness, and divergence were calculated to reflect the species and functional diversity of plant communities. Environmental factors including elevation above water level, slope, landform type, substrate, disturbance, and cover were measured. The results showed that both species and functional richness were significantly lower on reservoir shorelines than in riparian wetlands. The relative species number of clonal plants and relative cover of annual plants were both negatively related to slope and elevation. Structural equation modeling and other statistical analyses indicated that most environmental factors had significant effects on species and functional richness on reservoir shorelines but had no significant effect on functional evenness and divergence. Our findings suggest that reservoir shoreline wetlands formed by damming rivers and inundating pre-existing riparian wetlands can be a biodiversity coldspot in regulated rivers at the plot level. Topographic factors are important in determining the plant diversity and vegetation establishment on reservoir shorelines in the Yangtze River basin.

  15. Antioxidant enzymes and proteins of wetland plants: their relation to Pb tolerance and accumulation.

    PubMed

    Yang, Junxing; Ye, Zhihong

    2015-02-01

    Constructed wetlands used to clean up toxic metals such as lead (Pb) from contaminated wastewater are considered as an effective and low-cost technology. The effect of Pb on the biomass, tolerance, soluble protein, and antioxidant enzymes in 18 candidate wetland plant species grown in soils without (control) and spiked with 900 and 1800 mg Pb kg(-1) was studied in a pot trial. Our pot experiment showed that the biomass, tolerance, and leaf protein contents decreased with increasing concentrations of Pb in soil. There were significant differences between the plants in their Pb tolerance indices (29-82 % in the 900 mg Pb kg(-1) amended soil) and also Pb uptake (13-749 mg kg(-1) in shoots and 1112-4891 mg kg(-1) in roots, in the same treatments). Activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of most of the plants increased with increasing level of soil Pb concentration. Conversely, catalase (CAT) activity in leaves declined when plants were subjected to Pb stress. Lead accumulation by the 18 wetland plant species screened was strongly dependent on the species and Pb concentrations in the soil. However, Pb translocation from root to shoot was generally low in all species. Increases in SOD and POD activities suggest that the antioxidant system may play an important role in alleviating Pb toxicity in wetland plants. The data obtained should help in future species selection for the use in designing wetlands in Pb-contaminated environments.

  16. Conceptual hierarchical modeling to describe wetland plant community organization

    USGS Publications Warehouse

    Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

    2010-01-01

    Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

  17. Landfill leachate treatment by an experimental subsurface flow constructed wetland in tropical climate countries.

    PubMed

    Ujang, Z; Soedjono, E; Salim, M R; Shutes, R B

    2005-01-01

    Municipal leachate was treated in an experimental unit of constructed wetlands of subsurface flow type. The parameters studied were organics (BOD and COD), solids and heavy metals (Zn, Ni, Cu, Cr and Pb). Using two types of emergent plants of Scirpus globulosus and Eriocaulon sexangulare, more than 80% removal was achieved for all the parameters. E. sexangulare removed organics and heavy metals better than Scirpus globulosus. A higher concentration of heavy metals in the influent did not change the removal efficiency.

  18. Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

    PubMed

    He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

    2013-10-01

    Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing

  19. Effects of perchlorate on growth of four wetland plants and its accumulation in plant tissues.

    PubMed

    He, Hongzhi; Gao, Haishuo; Chen, Guikui; Li, Huashou; Lin, Hai; Shu, Zhenzhen

    2013-10-01

    Perchlorate contamination in water is of concern because of uncertainties about toxicity and health effects, impact on ecosystems, and possible indirect exposure pathways to humans. Therefore, it is very important to investigate the ecotoxicology of perchlorate and to screen plant species for phytoremediation. Effects of perchlorate (20, 200, and 500 mg/L) on the growth of four wetland plants (Eichhornia crassipes, Acorus calamus L., Thalia dealbata, and Canna indica) as well as its accumulation in different plant tissues were investigated through water culture experiments. Twenty milligrams per liter of perchlorate had no significant effects on height, root length, aboveground part weight, root weight, and oxidizing power of roots of four plants, except A. calamus, and increasing concentrations of perchlorate showed that out of the four wetland plants, only A. calamus had a significant (p<0.05) dose-dependent decrease in these parameters. When treated with 500 mg/L perchlorate, these parameters and chlorophyll content in the leaf of plants showed significant decline contrasted to control groups, except the root length of E. crassipes and C. indica. The order of inhibition rates of perchlorate on root length, aboveground part weight and root weight, and oxidizing power of roots was: A. calamus > C. indica > T. dealbata > E. crassipes and on chlorophyll content in the leaf it was: A. calamus > T. dealbata > C. indica > E. crassipes. The higher the concentration of perchlorate used, the higher the amount of perchlorate accumulation in plants. Perchlorate accumulation in aboveground tissues was much higher than that in underground tissues and leaf was the main tissue for perchlorate accumulation. The order of perchlorate accumulation content and the bioconcentration factor in leaf of four plants was: E. crassipes > C. indica > T. dealbata > A. calamus. Therefore, E. crassipes might be an ideal plant with high tolerance ability and accumulation ability for constructing

  20. Application of a constructed wetland system for polluted stream remediation

    NASA Astrophysics Data System (ADS)

    Tu, Y. T.; Chiang, P. C.; Yang, J.; Chen, S. H.; Kao, C. M.

    2014-03-01

    In 2010, the multi-function Kaoping River Rail Bridge Constructed Wetland (KRRBW) was constructed to improve the stream water quality and rehabilitate the ecosystem of the surrounding environment of Dashu Region, Kaohsiung, Taiwan. The KRRBW consists of five wetland basins with a total water surface area of 15 ha, a total hydraulic retention time (HRT) of 10.1 days at a averaged flow rate of 14 740 m3/day, and an averaged water depth of 1.1 m. The influent of KRRBW coming from the local drainage systems containing untreated domestic, agricultural, and industrial wastewaters. Based on the quarterly investigation results of water samples taken in 2011-2012, the overall removal efficiencies were 91% for biochemical oxygen demand (BOD), 75% for total nitrogen (TN), 96% for total phosphorus (TP), and 99% for total coliforms (TC). The calculated first-order decay rates for BOD, TN, TP, NH3-N, and TC ranged from 0.14 (TN) to 0.42 (TC) 1/day. This indicates that the KRRBW was able to remove organics, TC, and nutrients effectively. The high ammonia/nitrate removal efficiency indicates that nitrification and denitrification processes occurred simultaneously in the wetland system, and the detected nitrite concentration confirmed the occurrence of denitrification/nitrification. Results from sediment analyses reveal that the sediment contained high concentrations of organics (sediment oxygen demand = 1.9-5.2 g O2/m2 day), nutrients (up to 15.8 g total nitrogen/kg of sediment and 1.48 g total phosphorus/kg of sediment), and metals (up to 547 mg/kg of Zn and 97 mg/kg of Cu). Appropriate wetland management strategies need to be developed to prevent the release of contaminants into the wetland system. The wetland system caused the variations in the microbial diversities and dominant microbial bacteria. Results show the dominant nitrogen utilization bacteria including Denitratisoma oestradiolicum, Nitrosospira sp., Nitrosovibrio sp., D. oestradiolicum, Alcaligenes sp

  1. Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems.

    PubMed

    Schmidt, Marie; Wolfram, Diana; Birkigt, Jan; Ahlheim, Jörg; Paschke, Heidrun; Richnow, Hans-Hermann; Nijenhuis, Ivonne

    2014-02-15

    Natural wetlands are transition zones between anoxic ground and oxic surface water which may enhance the (bio)transformation potential for recalcitrant chloro-organic contaminants due to the unique geochemical conditions and gradients. Monochlorobenzene (MCB) is a frequently detected groundwater contaminant which is toxic and was thought to be persistent under anoxic conditions. Furthermore, to date, no degradation pathways for anoxic MCB removal have been proven in the field. Hence, it is important to investigate MCB biodegradation in the environment, as groundwater is an important drinking water source in many European countries. Therefore, two pilot-scale horizontal subsurface-flow constructed wetlands, planted and unplanted, were used to investigate the processes in situ contributing to the biotransformation of MCB in these gradient systems. The wetlands were fed with anoxic MCB-contaminated groundwater from a nearby aquifer in Bitterfeld, Germany. An overall MCB removal was observed in both wetlands, whereas just 10% of the original MCB inflow concentration was detected in the ponds. In particular in the gravel bed of the planted wetland, MCB removal was highest in summer season with 73 ± 9% compared to the unplanted one with 40 ± 5%. Whereas the MCB concentrations rapidly decreased in the transition zone of unplanted gravel to the pond, a significant MCB removal was already determined in the anoxic gravel bed of the planted system. The investigation of hydro-geochemical parameters revealed that iron and sulphate reduction were relevant redox processes in both wetlands. In parallel, the addition of ferric iron or nitrate stimulated the mineralisation of MCB in laboratory microcosms with anoxic groundwater from the same source, indicating that the potential for anaerobic microbial degradation of MCB is present at the field site.

  2. Invertebrates associated with a horizontal-flow, subsurface constructed wetland in a northern climate.

    PubMed

    Giordano, Rosanna; Weber, Everett; Darby, Brian J; Soto-Adames, Felipe N; Murray, Robert E; Drizo, Aleksandra

    2014-04-01

    Wetlands function as buffers between terrestrial and aquatic ecosystems, filtering pollutants generated by human activity. Constructed wetlands were developed to mimic the physical and biological filtering functions of natural systems for the treatment of human and animal waste under controlled conditions. Previous studies on the effect of constructed wetlands on native invertebrate populations have concentrated almost exclusively on mosquitoes. Here, we present the first study investigating the relationship between vegetation cover and aeration regime, and the diversity and abundance of nematodes and springtails (Collembola) in a constructed wetland designed to treat dairy farm wastewater in northwestern Vermont. We investigated four treatment cells differing in aeration regime and vegetation cover, but equally overlaid by a layer of compost to provide insulation. Analysis showed that nematodes were most abundant in the nonplanted and nonaerated cells, and that bacterivorous nematodes dominated the community in all cells. Springtails were found to be most numerous in the planted and nonaerated cells. We hypothesize that the vegetation provided differing environmental niches that supported a more diverse system of bacteria and fungi, as well as offering protection from predators and inclement weather. Nematodes were likely imported with the original compost material, while springtails migrated into the cells either via air, water, or direct locomotion. PMID:24534015

  3. Invertebrates associated with a horizontal-flow, subsurface constructed wetland in a northern climate.

    PubMed

    Giordano, Rosanna; Weber, Everett; Darby, Brian J; Soto-Adames, Felipe N; Murray, Robert E; Drizo, Aleksandra

    2014-04-01

    Wetlands function as buffers between terrestrial and aquatic ecosystems, filtering pollutants generated by human activity. Constructed wetlands were developed to mimic the physical and biological filtering functions of natural systems for the treatment of human and animal waste under controlled conditions. Previous studies on the effect of constructed wetlands on native invertebrate populations have concentrated almost exclusively on mosquitoes. Here, we present the first study investigating the relationship between vegetation cover and aeration regime, and the diversity and abundance of nematodes and springtails (Collembola) in a constructed wetland designed to treat dairy farm wastewater in northwestern Vermont. We investigated four treatment cells differing in aeration regime and vegetation cover, but equally overlaid by a layer of compost to provide insulation. Analysis showed that nematodes were most abundant in the nonplanted and nonaerated cells, and that bacterivorous nematodes dominated the community in all cells. Springtails were found to be most numerous in the planted and nonaerated cells. We hypothesize that the vegetation provided differing environmental niches that supported a more diverse system of bacteria and fungi, as well as offering protection from predators and inclement weather. Nematodes were likely imported with the original compost material, while springtails migrated into the cells either via air, water, or direct locomotion.

  4. How efficient are constructed wetlands in removing pharmaceuticals from untreated and treated urban wastewaters? A review.

    PubMed

    Verlicchi, Paola; Zambello, Elena

    2014-02-01

    This review presents and discusses the data from 47 peer-reviewed journal articles on the occurrence of 137 pharmaceutical compounds in the effluent from various types of constructed wetlands treating urban wastewater. We analyse the observed removal efficiencies of the investigated compounds in order to identify the type of constructed wetland that best removes those most frequently detected. The literature reviewed details experimental investigations carried out on 136 treatment plants, including free water surface systems, as well as horizontal and vertical subsurface flow beds (pilot or full-scale) acting as primary, secondary or tertiary treatments. The occurrence of selected pharmaceuticals in sediments and gravel and their uptake by common macrophytes are also presented and discussed. We analyse the main removal mechanisms for the selected compounds and investigate the influence of the main design parameters, as well as operational and environmental conditions of the treatment systems on removal efficiency. We also report on previous attempts to correlate observed removal values with the chemical structure and chemical-physical properties (mainly pKa and LogKow) of pharmaceutical compounds. We then use the literature data to calculate the average pharmaceutical mass loadings in the effluent from constructed wetlands, comparing the ability of such systems to remove selected pharmaceuticals with the corresponding conventional secondary and tertiary treatments. Finally, the environmental risk posed by pharmaceutical residues in effluents from constructed wetlands acting as secondary and tertiary treatment steps is calculated in the form of the risk quotient ratio. This approach enabled us to provide a ranking of the most critical compounds for the two scenarios, to discuss the ramifications of the adoption of constructed wetlands for removing such persistent organic compounds, and to propose avenues of future research.

  5. Bioremediation of endosulfan in laboratory-scale constructed wetlands: effect of bioaugmentation and biostimulation.

    PubMed

    Zhao, Congcong; Xie, HuiJun; Mu, Yang; Xu, Xiaoli; Zhang, Jian; Liu, Cui; Liang, Shuang; Ngo, Huu Hao; Guo, Wenshan; Xu, Jingtao; Wang, Qian

    2014-11-01

    Bioremediation is widely used in organic pollutants disposal. However, very little has been known on its application in constructed wetlands contaminated with organochlorine pesticide, endosulfan in particular. To evaluate the effect of bioremediation on endosulfan removal and clarify the fate, bioaugmentation and biostimulation were studied in laboratory-scale vertical-flow constructed wetlands. After 20 days' experiment, endosulfan isomers removal efficiencies were increased to 89.24-97.62 % through bioremediation. In bacteria bioaugmentation (E-in) and sucrose biostimulation (E-C), peak concentrations of endosulfan in sediment were reduced by 31.02-76.77 %, and plant absorption were 347.45-576.65 μg kg(-1). By contrast, plant absorption in KH2PO4 biostimulation (E-P) was increased to 811.64 and 1,067.68 μg kg(-1). Degradation process was probably promoted in E-in and E-C, while plant absorption was enhanced in E-P. Consequently, E-in and E-C were effective for endosulfan removal in constructed wetlands, while adding KH2PO4 had potential to cause air pollution. Additionally, combined bioremediation was not recommended. PMID:24969425

  6. Efficient removal of antibiotics in surface-flow constructed wetlands, with no observed impact on antibiotic resistance genes.

    PubMed

    Berglund, Björn; Khan, Ghazanfar Ali; Weisner, Stefan E B; Ehde, Per Magnus; Fick, Jerker; Lindgren, Per-Eric

    2014-04-01

    Recently, there have been growing concerns about pharmaceuticals including antibiotics as environmental contaminants. Antibiotics of concentrations commonly encountered in wastewater have been suggested to affect bacterial population dynamics and to promote dissemination of antibiotic resistance. Conventional wastewater treatment processes do not always adequately remove pharmaceuticals causing environmental dissemination of low levels of these compounds. Using constructed wetlands as an additional treatment step after sewage treatment plants have been proposed as a cheap alternative to increase reduction of wastewater contaminants, however this means that the natural microbial community of the wetlands becomes exposed to elevated levels of antibiotics. In this study, experimental surface-flow wetlands in Sweden were continuously exposed to antibiotics of concentrations commonly encountered in wastewater. The aim was to assess the antibiotic removal efficiency of constructed wetlands and to evaluate the impact of low levels of antibiotics on bacterial diversity, resistance development and expression in the wetland bacterial community. Antibiotic concentrations were measured using liquid chromatography-mass spectrometry and the effect on the bacterial diversity was assessed with 16S rRNA-based denaturing gradient gel electrophoresis. Real-time PCR was used to detect and quantify antibiotic resistance genes and integrons in the wetlands, during and after the exposure period. The results indicated that the antibiotic removal efficiency of constructed wetlands was comparable to conventional wastewater treatment schemes. Furthermore, short-term treatment of the constructed wetlands with environmentally relevant concentrations (i.e. 100-2000 ng×l(-1)) of antibiotics did not significantly affect resistance gene concentrations, suggesting that surface-flow constructed wetlands are well-suited for wastewater treatment purposes.

  7. Efficiency of constructed wetlands for residential wastewater treatment

    SciTech Connect

    Leonard, K.M.

    1998-07-01

    One of the major water quality concerns in many areas of the country is finding alternative methods for on-site, residential wastewater treatment systems. In response to this issue, there has recently been a rush of interest in constructed wetlands as a practical, natural alternative. This paper documents the performance of such residential systems under for a broad range of temperatures and recommends adjusted input parameters for the two most popular design models.

  8. Exploring fecal indicator bacteria in a constructed stormwater wetland.

    PubMed

    Hathaway, J M; Hunt, W F; Graves, A K; Bass, K L; Caldwell, A

    2011-01-01

    Microbial pollution in surface waters is a concern throughout the world, with both public health and economic implications. One contributing source to such pollution is stormwater runoff, often treated using various types of stormwater control measures. However, relatively little is known regarding microbe sequestration in constructed stormwater wetlands (CSWs), one type of commonly installed stormwater control measure. In this study, indicator bacteria concentrations in both the water and sediment of a CSW were evaluated at multiple locations. Results suggested that fecal coliform concentrations in stormwater runoff decrease through the system, with relatively consistent concentrations noted throughout the second half of the wetland. This potentially indicates a baseline concentration of fecal coliform is present due to internal processes such as animal activity and microbial persistence. However, wetland sediments showed little E. coli present during most sampling events, with minimal patterns existing with respect to sediment sampling location. CSW designs should promote optimization of hydraulic retention time and minimization of stormwater velocities to promote sedimentation and degradation of microbes by way of wetland treatment functions.

  9. Kinetic and empirical design criteria for constructed wetlands

    SciTech Connect

    Nix, P.G.; Gulley, J.R.

    1995-12-31

    Design criteria were derived for estimating the size of constructed wetlands needed to treat oil sands mining wastewater using a field-scale wetland experimental facility in northeastern Alberta, Canada. The objective of this research was to demonstrate the capabilities of such wetlands as long-term, self-sustaining ``natural`` systems for the treatment of large quantities of wastewater anticipated to be released from tailings ponds after mine abandonment. Using empirical data (i.e., hydrocarbon loading rates versus effluent quality), the optimal range of hydrocarbon loading was 5 to 25 gTEH/m{sup 2}/month. Using more conservative kinetic data (i.e., microbial mineralization rates), the range of optimal treatment effectiveness was 9.6 to 13.2 gTEH/m{sup 2}/month. Since these two design criteria methodologies were calculated using two independent analytical methods, the similarity in results represents a substantial validation of their accuracy. Further research is being undertaken to confirm these findings, to improve treatment performance, and to assess the ecological characteristics of these wetlands.

  10. Nitrogen Isotopes - Tracers for Nitrogen Transformations in Small Constructed Wetlands

    NASA Astrophysics Data System (ADS)

    Reinhardt, M.; Gaechter, R.; Mueller, B.; Wehrli, B.

    2005-05-01

    Small artificial wetlands are increasingly applied to reduce non-point source pollution and to contribute to the restoration of eutrophicated freshwaters and coastal marine ecosystems. In the agricultural catchment area of Lake Sempach in Central Switzerland, several wetlands were constructed at the interface between subsurface drainage system and receiving waters. In order to evaluate nitrogen retention efficiency of the systems and to identify major processes controlling their performance, nitrate, ammonium, particulate and dissolved organic nitrogen in the inflowing and outflowing water as well as δ15N of nitrate, ammonium and sediment were analyzed in a three pond system. During the studied 26 months the wetland retained 27% of the nitrogen load corresponding to a surface related retention of 51g N m-2 yr-1. Nitrate in the inlet contributed 48% to the total nitrogen load and was characterized by high δ15N-NO3(>13‰) typical for intensively manured grassland soils. Increasing δ15N-NO3 in the wetland compared to the inlet was attributed to denitrification whereas decreasing δ15N-NO3 during stagnant periods was due to anoxic mineralization of particulate organic matter and subsequent nitrification.

  11. Study of Geochemical System in Constructed Wetland Using Multivariate Statistical Analysis

    NASA Astrophysics Data System (ADS)

    Chen, V.

    2015-12-01

    People have recognized that the human activities lead to the degradation of the environment, and constructed wetland is one of the well-known technologies for water treatment. In constructed wetland, complicated processes should be considered such as redox reactions, acid-base reactions, adsorption-desorption between water and sediment and biochemical reactions associated with plant and microorganism. In this study, most of inorganic components were analyzed and principal component analysis (PCA) was followed for depicting the controlling biochemical reaction in the constructed wetland. The results could be a guide to operate the constructed wetland. The constructed wetland in this study is located in Taoyuan County, north Taiwan. It's a horizontal subsurface flow constructed wetland composed of ten cells. The water in wetland was pumped from Nankan River, which collects wastewater from Hwaya technology park, Linkou, Guishan and Nankan industrial zone. The water of inflow and outflow from each cell were collected for analyzing inorganic components with ICP-MS and IC. In general, the results show that water quality had dramatically changed in the first three cells and became stable in the following seven cells. In this study, PCA extracted two major factors (PCs), which can respectively explain 52.76%(PC1)and 28.32%(PC2)of variance of water quality data. PC1 separates samples of the first three cells from those of the other following cells. It is believed that there was another pollution source involved in the 4th cell because PC1 is characterized by high loadings of most of trace heavy metals. On the other hand, the hydrochemistry of water mainly evolve along PC2 axis. PC2 is composed of Fe, Mn, NH4, dissolved oxygen, pH, etc with high loadings. These chemical components are predominately controlled by redox reactions. Moreover, the deep water from the 4th cell contains high concentrations of many heavy metals, especially Cu and Ga. This confirms the

  12. Characterisation of the soil bacterial community structure and composition of natural and constructed wetlands.

    PubMed

    Ansola, Gemma; Arroyo, Paula; Sáenz de Miera, Luis E

    2014-03-01

    In the present study, the pyrosequencing of 16S ribosomal DNA was used to characterise the soil bacterial community composition of a constructed wetland receiving municipal wastewater and a nearby natural wetland. Soil samples were taken from different locations in each wetland (lagoon, zone with T. latifolia, zone with S. atrocinerea). Moreover, the water quality parameters were evaluated (pH, Tª, conductivity, dissolved oxygen, redox potential, nutrients and suspended solids), revealing that the organic matter and nutrient contents were significantly higher in the constructed wetland than in the natural one. In general, the bacterial communities of the natural wetland were more diverse than those of the constructed wetland. The major phylogenic groups of all soils included Proteobacteria, Verrucomicrobia and Chloroflexi, with Proteobacteria being the majority of the community composition. The Verrucomicrobia and Chloroflexi phyla were more abundant in the natural wetland than the constructed wetland; in contrast, the Proteobacteria phylum was more abundant in the constructed wetland than the natural wetland. Beta diversity analyses reveal that the soil bacterial communities in the natural wetland were less dissimilar to each other than to those of the constructed wetland.

  13. Does batch operation enhance oxidation in subsurface constructed wetlands?

    PubMed

    Stein, O R; Hook, P B; Biederman, J A; Allen, W C; Borden, D J

    2003-01-01

    Two side-by-side experimental sub-surface flow systems allowed direct comparison of wetland performance under batch and continuous-flow operation. One system consisted of microcosm "columns" operated in 20-day batch mode while the second consisted of continuous-flow "cells" operated at a five-day residence time. Both systems treated identical synthetic domestic wastewater for two years and then treated identical synthetic mine-impacted water for one year. Each system had replicates planted with Typha latifolia, Scirpus acutus and unplanted controls. Temperature was cycled annually between 4 to 24 degrees C. Results indicated that plant species, season, and mode of operation interacted strongly in controlling dynamics of COD, nitrogen species, phosphate, sulfate, and redox potentials. In batch-loaded columns, between-species differences in oxidation and COD removal were large in winter, during plant dormancy, but absent in summer; COD removal, sulfate concentration, and redox potentials were closely correlated, suggesting that variation in root-zone oxygenation due to seasonal plant growth patterns and temperature-dependent plant and microbial respiration may explain observed differences. In the continuous-flow cells, species and seasonal differences were minimal or non-existent, indicating that under continuous-flow operation plants either did not influence root zone oxidation or that this influence had no effect on wetland performance for COD and nutrient removal or sulfate reduction.

  14. Slag columns for upgrading phosphorus removal from constructed wetland effluents.

    PubMed

    Chazarenc, F; Brisson, J; Comeau, Y

    2007-01-01

    The current best option to upgrade constructed wetlands (CWs) for phosphorus (P) retention, in terms of efficiency, cost and simplicity, consists in using media having a strong P affinity. The media can be used either in the planted beds or in a filtration system downstream of the beds. The use of slag filters was shown to be efficient for removing P from wastewater as it represented a slow release source of calcium and hydroxide, favouring the formation of hydroxyapatite. Our study aimed at maximising the P retention capacity of slag filters located at the outlet of CWs since electric arc furnace slag has been shown to inhibit the growth of macrophytes when used in the filtration matrix. Bench-scale columns (Vtot = 6.2 L) filled with various combinations of filter media (slag, granite, limestone) of different sizes (2-5, 5-10, 10-20 mm) were fed on-site during four months with a CW effluent (in mg/L: 30 COD, 30 TSS, 10 Pt). Results showed that the best media combination enabling the maximum o-PO4 retention (more than 80% removal without clogging) consisted in a series of a ternary mix column (slag 5-10 mm, granite 2-5 mm, limestone 5-10 mm) followed by a slag column (slag 5-10 mm). Pilot scale columns (Vtot = 300 L), filled with the best media combination, were installed at the outlet of a 28 m2 CW. These columns showed more than 75% removal efficiency during one year and were designed to be easily replaced each year.

  15. Influence of chlorothalonil on the removal of organic matter in horizontal subsurface flow constructed wetlands.

    PubMed

    Casas-Zapata, Juan C; Ríos, Karina; Florville-Alejandre, Tomás R; Morató, Jordi; Peñuela, Gustavo

    2013-01-01

    This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.

  16. Influence of chlorothalonil on the removal of organic matter in horizontal subsurface flow constructed wetlands.

    PubMed

    Casas-Zapata, Juan C; Ríos, Karina; Florville-Alejandre, Tomás R; Morató, Jordi; Peñuela, Gustavo

    2013-01-01

    This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT. PMID:23305280

  17. Evaluation of constructed ponds as a means of replacing natural wetland habitat affected by highway projects in North Dakota - Phase 2. Final report, July 1981-March 1986

    SciTech Connect

    Kreil, K.L.; Crawford, R.D.

    1986-03-01

    Landfill extraction during highway expansion resulted in construction of artificial wetlands in Pembina, Barnes, Nelson and Ramsey Counties, North Dakota. Twenty of these constructed wetlands were studied from 1981 to 1984 to determine (1) waterfowl pair, nesting and brood use, (2) marsh, shore and upland bird use, and (3) abundance and diversity of plants and aquatic invertebrates. Comparisons were made between data collected on constructed ponds with six natural basins nearby.

  18. Fate of Volatile Organic Compounds in Constructed Wastewater Treatment Wetlands

    USGS Publications Warehouse

    Keefe, S.H.; Barber, L.B.; Runkel, R.L.; Ryan, J.N.

    2004-01-01

    The fate of volatile organic compounds was evaluated in a wastewater-dependent constructed wetland near Phoenix, AZ, using field measurements and solute transport modeling. Numerically based volatilization rates were determined using inverse modeling techniques and hydraulic parameters established by sodium bromide tracer experiments. Theoretical volatilization rates were calculated from the two-film method incorporating physicochemical properties and environmental conditions. Additional analyses were conducted using graphically determined volatilization rates based on field measurements. Transport (with first-order removal) simulations were performed using a range of volatilization rates and were evaluated with respect to field concentrations. The inverse and two-film reactive transport simulations demonstrated excellent agreement with measured concentrations for 1,4-dichlorobenzene, tetrachloroethene, dichloromethane, and trichloromethane and fair agreement for dibromochloromethane, bromo-dichloromethane, and toluene. Wetland removal efficiencies from inlet to outlet ranged from 63% to 87% for target compounds.

  19. Pilot-scale constructed wetlands for petroleum-contaminated groundwater.

    PubMed

    Bedessem, Marjorie E; Ferro, Ari M; Hiegel, Trevor

    2007-06-01

    A pilot study was conducted to determine the feasibility of using constructed treatment wetlands to remediate recovered groundwater from the subsurface of a former refinery site. The pilot system consisted of four subsurface flow treatment cells operated in an upward vertical flow mode and equipped with subsurface aeration lines. The treatment system showed minimal capability for methyl-tert-butyl ether removal, but did effectively remove total petroleum hydrocarbons-deisel range organics and total benzene, toluene, ethylbenzene, and o-, m-, and p-xylenes (total BTEX). Effluent benzene concentrations were less than 0.05 mg/L in 70% of the samples from a treatment cell using subsurface aeration and a wetland sod amendment. Based on 1 year of operating data, cumulative mass removal approached 80% for benzene and 88% for total BTEX.

  20. Constructed wetland treatment systems for the remediation of metal- bearing aqueous discharges. Final report

    SciTech Connect

    Woodis, A.L.

    1995-08-01

    Electric utility activities, such as coal mining, processing, and combustion, often produce aqueous (wastewater) discharges containing metals. Chemical treatment of these discharges to achieve compliance with National Pollution Discharge Elimination System (NPDES) requirements can be costly. Constructed wetland treatment systems offer an inexpensive, natural, low-maintenance, and potentially long-term solution for the treatment of aqueous discharges without chemical additives. At the present time, several electric utilities are using constructed wetland treatment systems to achieve NPDES compliance. Constructed wetland treatment systems take advantage of natural biogeochemical processes to treat utility wastewaters, thus meeting NPDES compliance levels in an environmentally effective manner. This report provides information on the natural science, wastewater treatment, and regulatory/jurisdictional aspects of constructed wetland treatment systems used within the electric utility industry. Included is data from a number of electric utility constructed wetland treatment sites. The principal advantages of using constructed wetland systems to treat wastewater are the low overall cost compared to more conventional chemical treatment methods, the simplicity of operation, and the capacity to provide long-term resource recovery. For example, using a lined constructed wetland treatment system with high retention efficiency for heavy metals provides the option of resource recovery at some future date from a discrete volume of wetland material. Contaminants that can be removed with high efficiency in a number of constructed wetland treatment systems include heavy metals, toxic organics, suspended solids, and nutrients. This report discusses the treatability of specific contaminants as well as metal uptake and translocation processes in constructed wetlands.

  1. Plant biodiversity changes in Carboniferous tropical wetlands

    NASA Astrophysics Data System (ADS)

    Cleal, C. J.; Uhl, D.; Cascales-Miñana, B.; Thomas, B. A.; Bashforth, A. R.; King, S. C.; Zodrow, E. L.

    2012-08-01

    Using a combination of species richness, polycohort and constrained cluster analyses, the plant biodiversity of Pennsylvanian (late Carboniferous) tropical wetlands ("coal swamps") has been investigated in five areas in Western Europe and eastern North America: South Wales, Pennines, Ruhr, Saarland and Sydney coal basins. In all cases, species richness expansion followed an essentially logistic curve typical of that associated with ecologically closed habitats, with niche saturation being achieved in about three million years. The resulting steady-state ("climax") coal swamp vegetation had a local-scale (within an area of c. 0.1 ha) species diversity in South Wales of 16 ± 7 and Simpson Diversity Indices of 4.53 ± 2.55, which are very similar to values obtained from studies on North American coal swamp vegetation. Landscape diversity (within an area 105 km2) varied between 50 and 100 species in the lower to middle Westphalian Stage, falling to about 40-50 species in the upper Westphalian Stage. Regional-scale diversity (within an area > 105 km2) is difficult to estimate but was at least 120 species. Species turn-over was typically very low, at about 4 species per million years, but there were a number of intervals of more rapid species turn-over in the early Langsettian, late Duckmantian, early Bolsovian and middle Asturian times, which are recognised today as biozonal boundaries. The swamps were mostly subject to ecological stasis during early and middle Westphalian times, although they contracted locally in response to drying of substrates. Later in Westphalian times, however, the swamps were subject to regional-scale changes in composition and aerial extent, probably in response to climate change. The coal swamps had a much lower species diversity compared to modern-day tropical rain forests.

  2. Nitrogen transformation in horizontal subsurface flow constructed wetlands I: Model development

    NASA Astrophysics Data System (ADS)

    Mayo, A. W.; Bigambo, T.

    In this paper a mathematical model for prediction of nitrogen transformation in horizontal subsurface flow constructed wetlands was developed. Two horizontal subsurface flow constructed wetlands were designed to receive organic loading rate below 50 kg/ha/d and hydraulic loading rate of 480 m 3/ha/d from a primary facultative pond. Two rectangular shaped units each 11.0 m long, 3.7 m wide and 1.0 m deep and bottom slope of 1% were constructed and filled with 6-25 mm diameter gravel pack to a depth of 0.75 m. Each unit was planted with Phragmites mauritianus with an initial plant density of 29,000 plants/ha. The plants were allowed to grow for about four months before sampling for water quality parameters commenced. Samples were collected daily for about three months. Dissolved oxygen, pH and temperature were measured in situ and ammonia, total Kjeldahl nitrogen, nitrates, nitrite and Chemical Oxygen Demand were measured in the laboratory in accordance with Standard Methods. The mathematical model took into account activities of biomass suspended in the water body and biofilm on aggregates and plant roots. The state variables modelled include organic, ammonia, and nitrate-nitrogen, which were sectored in water, plant and aggregates. The major nitrogen transformation processes considered in this study were mineralization, nitrification, denitrification, plant uptake, plant decaying, and sedimentation. The forcing functions, which were considered in the model, are temperature, pH and dissolved oxygen. Stella II software was used to simulate the nitrogen processes influencing the removal of nitrogen in the constructed wetland. One of the two-wetland units was used for model calibration and the second unit for model validation. The model results indicated that 0.872 gN/m 2 d was settled at the bottom of the wetland and on gravel bed and roots of the plants. However, 0.752 gN/m 2 d (86.2%) of the settled nitrogen was regenerated back to the water body, which means that

  3. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    PubMed

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs. PMID:25259785

  4. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    PubMed

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs.

  5. Heterotrophic bacterial activities and treatment performance of surface flow constructed wetlands receiving woodwaste leachate.

    PubMed

    Tao, Wendong; Hall, Ken J; Duff, Sheldon J B

    2006-07-01

    Heterotrophic activities were investigated by measuring 3H-leucine incorporation to bacterial protein and 14C-glucose turnover in surface flow constructed wetlands receiving woodwaste leachate. No significant longitudinal variation was found in heterotrophic activities of bacterioplankton. An open wetland, a vegetated wetland, and a fertilized vegetated wetland were used to examine the effects of vegetation and ammonium nitrate amendment. There was not a significant difference in treatment performance among the three wetlands, except for a significant pH increase and more efficient volatile fatty acids removal in the fertilized wetland. The fertilized wetland had the highest leucine incorporation rate and shortest glucose turnover time accompanied by the lowest glucose mineralization percentage, followed by the open wetland, then the vegetated wetland. Planktonic and sedimentary bacteria contributed to the majority of the total heterotrophic activities; epiphytic bacteria played a minor role. Heterotrophic activities were influenced by the availability of nutrient, electron acceptor, and organic substrate.

  6. [Excitation-Emission Matrix Fluorescence Spectra Characteristics of DOM in a Combined Constructed Wetland].

    PubMed

    Lü, Jing-jing; Zhang, Lie-yu; Xi, Bei-dou; Hou, Li-an; Li, Ming

    2015-08-01

    Using three-dimensional fluorescence technology, we studied fluorescent characteristics of two polluted rivers by a surface flow+vertical flow combined constructed wetlands of dissolving organic matter. The results showed that (1) the main sources of water-soluble humic organic matter in constructed wetland was biological metabolic input instead of terrigenous input; (2) in the later section of the surface flow constructed wetland, part of proteinoid substance changed into fulvic acid-like substance, which showed that the composition of dissolved organic matter and material structure tended to be stable after surface flow combined constructed wetland treatment; (3) it was of great significance that surface flow constructed wetland in structure transformation of water soluble organic matter, which could significantly improve the stability of water soluble organic matter. Surface flow+vertical flow combined constructed wetland process of dissolved organic matter had a good removal effect. PMID:26672296

  7. Hydroperiod regime controls the organization of plant species in wetlands.

    PubMed

    Foti, Romano; del Jesus, Manuel; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2012-11-27

    With urban, agricultural, and industrial needs growing throughout the past decades, wetland ecosystems have experienced profound changes. Most critically, the biodiversity of wetlands is intimately linked to its hydrologic dynamics, which in turn are being drastically altered by ongoing climate changes. Hydroperiod regimes, e.g., percentage of time a site is inundated, exert critical control in the creation of niches for different plant species in wetlands. However, the spatial signatures of the organization of plant species in wetlands and how the different drivers interact to yield such signatures are unknown. Focusing on Everglades National Park (ENP) in Florida, we show here that cluster sizes of each species follow a power law probability distribution and that such clusters have well-defined fractal characteristics. Moreover, we individuate and model those signatures via the interplay between global forcings arising from the hydroperiod regime and local controls exerted by neighboring vegetation. With power law clustering often associated with systems near critical transitions, our findings are highly relevant for the management of wetland ecosystems. In addition, our results show that changes in climate and land management have a quantifiable predictable impact on the type of vegetation and its spatial organization in wetlands.

  8. Hydroperiod regime controls the organization of plant species in wetlands

    PubMed Central

    Foti, Romano; del Jesus, Manuel; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2012-01-01

    With urban, agricultural, and industrial needs growing throughout the past decades, wetland ecosystems have experienced profound changes. Most critically, the biodiversity of wetlands is intimately linked to its hydrologic dynamics, which in turn are being drastically altered by ongoing climate changes. Hydroperiod regimes, e.g., percentage of time a site is inundated, exert critical control in the creation of niches for different plant species in wetlands. However, the spatial signatures of the organization of plant species in wetlands and how the different drivers interact to yield such signatures are unknown. Focusing on Everglades National Park (ENP) in Florida, we show here that cluster sizes of each species follow a power law probability distribution and that such clusters have well-defined fractal characteristics. Moreover, we individuate and model those signatures via the interplay between global forcings arising from the hydroperiod regime and local controls exerted by neighboring vegetation. With power law clustering often associated with systems near critical transitions, our findings are highly relevant for the management of wetland ecosystems. In addition, our results show that changes in climate and land management have a quantifiable predictable impact on the type of vegetation and its spatial organization in wetlands. PMID:23150589

  9. Using cerium anomaly as an indicator of redox reactions in constructed wetland

    NASA Astrophysics Data System (ADS)

    Liang, R.

    2013-12-01

    The study area, Chiayi County located in southern Taiwan, has highly developed livestock. The surface water has very low dissolved oxygen and high NH4. Under the situation, constructed wetland becomes the most effective and economic choice to treat the wastewater in the natural waterways. Hebao Island free surface constructed wetland started to operate in late 2006. It covers an area of 0.28 km2 and is subdivided into 3 major cells, which are sedimentation cell, 1st aeration cell with rooted plants and 2nd aeration cell with float plants. The water depth of cells ranges from 0.6 m to 1.2 m. The total hydraulic retention time is about a half day. In this study, the water samples were sequentially collected along the flow path. The results of hydrochemical analysis show that the untreated inflow water can be characterized with enriched NH4 (11 ppm), sulfate (6 ppm) and arsenic (50 ppb). The removal efficiency of NH4 in the first two cells is <15%. However, the efficiency dramatically increases in the 2nd aeration cell, which is over 90%. Simultaneously, almost all of the hydrochemical properties, including EC, Ca, Mg, As Fe, Mn and other heavy metals, decrease while dissolve oxygen increases close to saturated level and aluminum is almost doubled in the exit of constructed wetland. However, the removal of sulfate and phosphate is very weak. It is worth to note that arsenic is still higher than the permissible limits recommended by WHO (10 ppb). The wetland operation should be tuned to take more arsenic away in the future. As demonstrated in the above, oxidation reaction is the most dominant mechanism to remove pollutants from the wastewater; therefore, dissolved oxygen is traditionally considered as an important indicator to evaluate the operation efficiency of wetland. However, it would need longer time to achieve equilibrium state of redox reaction involving dissolved oxygen due to the slower reaction rate. For example, the input water in this study has fairly high

  10. Modeling Escherichia coli removal in constructed wetlands under pulse loading.

    PubMed

    Hamaamin, Yaseen A; Adhikari, Umesh; Nejadhashemi, A Pouyan; Harrigan, Timothy; Reinhold, Dawn M

    2014-03-01

    Manure-borne pathogens are a threat to water quality and have resulted in disease outbreaks globally. Land application of livestock manure to croplands may result in pathogen transport through surface runoff and tile drains, eventually entering water bodies such as rivers and wetlands. The goal of this study was to develop a robust model for estimating the pathogen removal in surface flow wetlands under pulse loading conditions. A new modeling approach was used to describe Escherichia coli removal in pulse-loaded constructed wetlands using adaptive neuro-fuzzy inference systems (ANFIS). Several ANFIS models were developed and validated using experimental data under pulse loading over two seasons (winter and summer). In addition to ANFIS, a mechanistic fecal coliform removal model was validated using the same sets of experimental data. The results showed that the ANFIS model significantly improved the ability to describe the dynamics of E. coli removal under pulse loading. The mechanistic model performed poorly as demonstrated by lower coefficient of determination and higher root mean squared error compared to the ANFIS models. The E. coli concentrations corresponding to the inflection points on the tracer study were keys to improving the predictability of the E. coli removal model.

  11. Modeling Escherichia coli removal in constructed wetlands under pulse loading.

    PubMed

    Hamaamin, Yaseen A; Adhikari, Umesh; Nejadhashemi, A Pouyan; Harrigan, Timothy; Reinhold, Dawn M

    2014-03-01

    Manure-borne pathogens are a threat to water quality and have resulted in disease outbreaks globally. Land application of livestock manure to croplands may result in pathogen transport through surface runoff and tile drains, eventually entering water bodies such as rivers and wetlands. The goal of this study was to develop a robust model for estimating the pathogen removal in surface flow wetlands under pulse loading conditions. A new modeling approach was used to describe Escherichia coli removal in pulse-loaded constructed wetlands using adaptive neuro-fuzzy inference systems (ANFIS). Several ANFIS models were developed and validated using experimental data under pulse loading over two seasons (winter and summer). In addition to ANFIS, a mechanistic fecal coliform removal model was validated using the same sets of experimental data. The results showed that the ANFIS model significantly improved the ability to describe the dynamics of E. coli removal under pulse loading. The mechanistic model performed poorly as demonstrated by lower coefficient of determination and higher root mean squared error compared to the ANFIS models. The E. coli concentrations corresponding to the inflection points on the tracer study were keys to improving the predictability of the E. coli removal model. PMID:24231031

  12. Evaluating the efficiency of toxicity abatement in a constructed wetland with Ceriodaphnia dubia.

    PubMed

    Belin, J I; McCaskey, T A; Black, M C

    2000-05-26

    Constructed wetlands are becoming increasingly popular as low-cost, high-efficiency means of treating agricultural and municipal wastewaters. Monitoring programs for constructed wetlands usually measure physical and chemical characteristics of wetland treatment, including hydraulic residence time and removal of nutrients (N, P), suspended solids, and biochemical oxygen demand (BOD). However, toxicity abatement is seldom measured as evidence of wetland treatment efficiency. In this study, toxicity tests combined with chemical measurements were employed to measure the efficiency of a constructed wetland in treating swine wastes during fall and winter sampling periods. Although the wetland system operated at three wastewater loading rates, only the high-loading-rate cells were tested because of their year-round flows. Wastewater samples were collected prior to, during, and following wetland treatment to track treatment progress as effluents passed through the wetland cells. Toxicity tests with Ceriodaphnia dubia showed significant toxicity abatement of wastewater as it progressed through the constructed wetland system; however, residual toxicity was still observed in the final wetland effluent. No seasonal differences were observed in toxicity abatement between fall and winter wastewater samples, although nitrate and BOD were removed more efficiently during the fall. Results suggest that, while the constructed wetland system is effective in reducing toxicity in swine wastewater, further pre- or posttreatment or additional dilution is necessary before treated effluents are discharged into surface water.

  13. Removal of fluoride and arsenic by pilot vertical-flow constructed wetlands using soil and coal cinder as substrate.

    PubMed

    Li, Juan; Liu, Xinchun; Yu, Zhisheng; Yi, Xin; Ju, Yiwen; Huang, Jing; Liu, Ruyin

    2014-01-01

    This study evaluated the performance of soil and coal cinder used as substrate in vertical-flow constructed wetlands for removal of fluoride and arsenic. Two duplicate pilot-scale artificial wetlands were set up, planted respectively with cannas, calamus and no plant as blank, fed with a synthetic sewage solution. Laboratory (batch) incubation experiments were also carried out separately to ascertain the fluoride and arsenic adsorption capacity of the two materials (i.e. soil and coal cinder). The results showed that both soil and coal cinder had quite high fluoride and arsenic adsorption capacity. The wetlands were operated for two months. The concentrations of fluoride and arsenic in the effluent of the blank wetlands were obviously higher than in the other wetlands planted with cannas and calamus. Fluoride and arsenic accumulation in the wetlands body at the end of the operation period was in range of 14.07-37.24% and 32.43-90.04%, respectively, as compared with the unused media. PMID:25116490

  14. Removal of fluoride and arsenic by pilot vertical-flow constructed wetlands using soil and coal cinder as substrate.

    PubMed

    Li, Juan; Liu, Xinchun; Yu, Zhisheng; Yi, Xin; Ju, Yiwen; Huang, Jing; Liu, Ruyin

    2014-01-01

    This study evaluated the performance of soil and coal cinder used as substrate in vertical-flow constructed wetlands for removal of fluoride and arsenic. Two duplicate pilot-scale artificial wetlands were set up, planted respectively with cannas, calamus and no plant as blank, fed with a synthetic sewage solution. Laboratory (batch) incubation experiments were also carried out separately to ascertain the fluoride and arsenic adsorption capacity of the two materials (i.e. soil and coal cinder). The results showed that both soil and coal cinder had quite high fluoride and arsenic adsorption capacity. The wetlands were operated for two months. The concentrations of fluoride and arsenic in the effluent of the blank wetlands were obviously higher than in the other wetlands planted with cannas and calamus. Fluoride and arsenic accumulation in the wetlands body at the end of the operation period was in range of 14.07-37.24% and 32.43-90.04%, respectively, as compared with the unused media.

  15. REMOTE DETENTION OF INVASIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

  16. REMOTE DETECTION OF INVASSIVE AND OPPORTUNISTIC PLANT SPECIES IN GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    Invasive and opportunistic plant species have been associated with wetland disturbance. Increases in the abundance of plant species such as common reed (Phragmites australis) in coastal Great Lakes wetlands are hypothesized to occur with shifts toward drier hydrologic regimes, fr...

  17. Driving forces behind the construction of an eco-compensation mechanism for wetlands in China

    NASA Astrophysics Data System (ADS)

    Wang, Changhai

    2016-09-01

    This research revealed important driving forces behind the construction of an eco-compensation mechanism for wetlands (DFEMW) in China. Using China's provincial panel data from 1978 to 2008, a fixed-effects model was used to analyze the impacts of agricultural production systems on wetlands. We identified three DFEMW as follows: the change of wetland resources and protection measures in China; declaration and implementation of the provincial Wetland Protection Ordinance; and wetland degradation by agricultural production systems, which necessitated the establishment of a wetland eco-compensation mechanism. In addition to the DFEMW, a significant positive correlation between wetland area and both rural population and gross agricultural production was identified, in addition to a negative correlation with chemical fertilizer usage, reservoir storage capacity, and irrigation area. The underlying reasons for the serious degradation and inadequate protection of wetlands were market failure and government failure; these were the driving forces behind the need to establish a wetland eco-compensation mechanism. From a governmental perspective, it has been difficult to rectify market failures in resource distribution and thus to prevent wetland degradation. Factors include conflicts of interest, lack of investment, effective special laws, a simple means to protect wetlands, and a multidisciplinary management system. Therefore, the key factor is the coordination of interest relationships between those who utilize wetlands and those who seek to minimize wetland degradation and effectively protect wetlands.

  18. Twenty years experience with constructed wetland systems in Denmark--what did we learn?

    PubMed

    Brix, H; Schierup, H H; Arias, C A

    2007-01-01

    Full scale constructed wetland systems for wastewater treatment have been in operation in Denmark since 1983, mainly for the treatment of domestic sewage from small villages. The systems are constructed as soil-based horizontal subsurface flow systems but, because of low soil hydraulic conductivity, surface runoff is evident in most of the systems. Two decades of experience show that soil-based systems are generally efficient in removing suspended solids and BOD, but the removal of nitrogen and phosphorus is lower (typically 30-50%) and the systems do not nitrify ammonium. Contrary to earlier claims, the reeds do not increase the hydraulic conductivity of cohesive soils as much as necessary to secure sub-surface flow. Operation needs of soil-based reed beds are low and normally restricted to emptying of the sedimentation tank, cleaning of the distribution system and mowing of the grass around the system. The dead plant material and accumulated litter on the surface of the systems improve performance after the initial years. A significant number of systems have been shut down or extended with other technologies in order to meet new effluent standards, particularly demands for nitrification. New constructed wetland systems are either compact vertical flow systems which provide good nitrification, willow systems with no discharge or restored wetland systems for nitrate removal. If efficient removal of phosphorus is required, this is achieved by chemical precipitation in the sedimentation tank.

  19. Constructed wetlands, 1991-2011: a review of research development, current trends, and future directions.

    PubMed

    Zhi, Wei; Ji, Guodong

    2012-12-15

    This study explores a bibliometric approach to quantitatively evaluate global scientific constructed wetlands research, and statistically assess current trends, and future directions using the Science Citation Index Expanded (SCI-EXPANDED) database from 1991 to 2011. Articles referencing constructed wetlands were analyzed by accessing the following: publication language, output characteristics, publication performance by country and institution, author keywords, title words, and KeyWords Plus. Synthetically analyzing three keyword types, we concluded that the dominant constructed wetlands research hotspots from 1991 to 2011 included water, nutrients, plants, and flow. These four hotspots remained the most dominant research areas throughout our study period, and are predicted to remain the top research emphases in the near future. "Soil" also exhibited a notable increase since 2005, and is likely to become another notable area of research interest in the future. "Phytoremediation" and "horizontal" were not identified in 1991-1995, but exhibited marked increases from 136th (0.5%) and 169th (0.7%) in 1996-2000, to 9th (3.8%) and 11th (4.3%) in 2006-2011, respectively. Therefore, given the heightened attention during the last 15 years, these topics are likely to become a primary research focus in upcoming years.

  20. Water Purification Characteristic of the Actual Constructed Wetland with Carex dispalata in a Cold Area

    NASA Astrophysics Data System (ADS)

    Tsuji, Morio; Yamada, Kazuhiro; Hiratsuka, Akira; Tsukada, Hiroko

    Carex dispalata, a native plant species applied in cold districts for water purification in constructed wetlands, has useful characteristics for landscape creation and maintenance. In this study, seasonal differences in purification ability were verified, along with comparison of frozen and non-frozen periods' performance. A wetland area was constructed using a “hydroponics method” and a “coir fiber based method”. Results show that the removal rates of BOD, SS, and Chl-a were high. On this constructed wetland reduces organic pollution, mainly phytoplankton, but the removal of nitrogen and phosphorus was insufficient. The respective mean values of influent and treated water during three years were 26.6 mg/L and 12.2 mg/L for BOD, and 27.9 mg/L and 7.5 mg/L for SS. The mean value of the BOD removal rate for the non-frozen period was 2.99 g/m2/d that for the frozen period was 1.86 g/m2/d. The removal rate followed the rise of the BOD load rate. The removal rate limits were about 4 g/m2/d during the frozen period and 15 g/m2/d during the non-frozen period. For operations, energy was unnecessary. The required working hours were about 20 h annually for all maintenance and management during operations.

  1. Removal of total suspended solids from wastewater in constructed horizontal flow subsurface wetlands.

    PubMed

    Manios, T; Stentiford, E I; Millner, P

    2003-06-01

    Subsurface horizontal flow experimental wetlands (reed beds), were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water plc (1996) and that of the USA, EPA (1988). Four different growing media were used with a combination of top soil, gravel, river sand, and mature sewage sludge compost, to determine the best substrate for total suspended solids (TSS) removal. Eight units were constructed, two for each growing media. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed to the beds for more than six months. All eight beds performed very well. The best performance was achieved by the gravel reed beds with an almost constant removal rate above 95% and an average effluent concentration of less than 10 mg/L. Soil based beds containing top soil and sand, managed to reach values of removal around 90%. The wetlands containing compost in their substrate, produced an effluent with average concentration of less than 30 mg/L and a percentage removal between 80% and 90%. As expected, there was no significant difference in the performance of planted and unplanted wetlands.

  2. Enhancement of azo dye Acid Orange 7 removal in newly developed horizontal subsurface-flow constructed wetland.

    PubMed

    Tee, Heng-Chong; Lim, Poh-Eng; Seng, Chye-Eng; Mohd Nawi, Mohd Asri; Adnan, Rohana

    2015-01-01

    Horizontal subsurface-flow (HSF) constructed wetland incorporating baffles was developed to facilitate upflow and downflow conditions so that the treatment of pollutants could be achieved under multiple aerobic, anoxic and anaerobic conditions sequentially in the same wetland bed. The performances of the baffled and conventional HSF constructed wetlands, planted and unplanted, in the removal of azo dye Acid Orange 7 (AO7) were compared at the hydraulic retention times (HRT) of 5, 3 and 2 days when treating domestic wastewater spiked with AO7 concentration of 300 mg/L. The planted baffled unit was found to achieve 100%, 83% and 69% AO7 removal against 73%, 46% and 30% for the conventional unit at HRT of 5, 3 and 2 days, respectively. Longer flow path provided by baffled wetland units allowed more contact of the wastewater with the rhizomes, microbes and micro-aerobic zones resulting in relatively higher oxidation reduction potential (ORP) and enhanced performance as kinetic studies revealed faster AO7 biodegradation rate under aerobic condition. In addition, complete mineralization of AO7 was achieved in planted baffled wetland unit due to the availability of a combination of aerobic, anoxic and anaerobic conditions.

  3. Effects of recycled FGD liner material on water quality and macrophytes of constructed wetlands: a mesocosm experiment.

    PubMed

    Ahn, C; Mitsch, W J; Wolfe, W E

    2001-03-01

    We investigated the use of flue-gas-desulfurization (FGD) by-products from electric power plant wet scrubbers as liners in wetlands constructed to improve water quality. Mesocosm experiments were conducted over two consecutive growing seasons with different phosphorus loadings. Wetland mesocosms using FGD liners retained more total and soluble reactive phosphorus, with lower concentrations in the leachate (first year) and higher concentrations in the surface water (second year). Leachate was higher in conductivity (second year) and pH (both years) in lined mesocosms. Surface outflow did not reveal any significant difference in physicochemical characteristics between lined and unlined mesocosms. There was no significant difference in total biomass production of wetland plants between lined and unlined mesocosms although lower average stem lengths and fewer stems bearing flowers were observed in mesocosms with FGD liners. Potentially phytotoxic boron was significantly higher in the belowground biomass of plants grown in lined mesocosms with low phosphorus loading. A larger-scale, long-term wetland experiment close to full scale is recommended from this two-year mesocosm study to better predict the potentially positive and negative effects of using FGD by-products in constructed wetlands.

  4. Emergent macrophytes select for nitrifying and denitrifying microorganisms in constructed wetlands

    NASA Astrophysics Data System (ADS)

    Trias, Rosalia; Ramió Pujol, Sara; Bañeras, Lluis

    2014-05-01

    The use of constructed wetlands for wastewater treatment is a reliable low-cost alternative that has been widely developed during the last years. Several processes involving plants, sediments, and microbial communities contribute to nitrogen removal in wetlands. Vegetation plays an important role in this process, not only by nutrient assimilation but also by the stimulation of the plant associated microbiota. Plants supply oxygen at the close proximity of the root surface that may favour ammonia oxidizers. At the same time, exudation of organic compounds potentially speeds-up denitrification in the anoxic environment. The aim of this work was to understand the plant-microbe interactions at the root level in the Empuriabrava free water surface constructed wetland (Spain). The roots of the macrophytes Typha latifolia, Typha angustifolia, Phragmites australis and Bolboschoenus maritimus were sampled at four dates from January to September 2012, covering all the stages of plant growth. Additionally, sediment surrounding vegetation and non-vegetated sediments were sampled. Microbial community structure was analysed by pyrosequencing of bacterial and archaeal 16S rDNA and functional genes (nirK, nirS, nosZ and amoA). Bacterial communities were significantly different in sediments of the vegetated areas compared to the root surface. Plant roots exhibited a higher proportion of proteobacteria whereas Actinobacteria were dominant in sediments. The nitrifiers Nitrosomonas sp. and Nitrosococcus sp. accounted for less than 1% of all sequences. Archaeal communities were dominated by the Miscellaneous Crenarchaeotic Groups C2 and C3 and Methanomicrobia. Higher relative abundances of MCG were found in roots of P. australis, B. maritimus and T. angustifolia. Ammonia oxidizing archaea accounted for less than 0.1% of all sequences but were consistently more abundant in sediment samples compared to roots. NirK and NirS-type bacterial communities showed clearly distinct distribution

  5. Effects of salinity on treatment of municipal wastewater by constructed mangrove wetland microcosms.

    PubMed

    Wu, Yan; Tam, N F Y; Wong, M H

    2008-01-01

    The effects of salinity on the removal of dissolved organic carbon and nutrients from municipal wastewater by constructed mangrove microcosms planted with Aegiceras corniculatum were investigated. During the four-month wastewater treatment, the treatment efficiency was reduced by high salinity, and the removal percentages of dissolved organic carbon, ammonia-N and inorganic N dropped from 91% to 71%, from 98% to 83% and from 78% to 56%, respectively, with salinity increasing from 0 to 30 parts per thousands (ppt). In spite of such inhibition at high salinity, 100% of the effluents discharge from the constructed mangrove microcosms still complied with the discharge standards set by the Hong Kong Government for Coastal Water Control Zones. These results suggested that constructed mangrove wetland treatment systems were promising to effectively treat municipal wastewater, even those with high salinity. In addition, the denitrification potential in soil was found to be retarded by the high salinity while mangrove plants grew best at 15 ppt salinity condition.

  6. ECOLOGICAL RELATIONSHIPS BETWEEN LANDSCAPE CHANGE AND PLANT GUILDS IN DEPRESSIONAL WETLANDS

    EPA Science Inventory

    Plant guilds used to measure the relationships between wetland plant community characteristics and landscape change around 31 depressional wetlands in central Ohio, USA. Characteristics of certain plant guilds within each wetland site are correlated with changes in: (a) area of u...

  7. Comparative quantification of oxygen release by wetland plants: electrode technique and oxygen consumption model.

    PubMed

    Wu, Haiming; Liu, Jufeng; Zhang, Jian; Li, Cong; Fan, Jinlin; Xu, Xiaoli

    2014-01-01

    Understanding oxygen release by plants is important to the design of constructed wetlands for wastewater treatment. Lab-scale systems planted with Phragmites australis were studied to evaluate the amount of oxygen release by plants using electrode techniques and oxygen consumption model. Oxygen release rate (0.14 g O2/m(2)/day) measured using electrode techniques was much lower than that (3.94-25.20 gO2/m(2)/day) calculated using the oxygen consumption model. The results revealed that oxygen release by plants was significantly influenced by the oxygen demand for the degradation of pollutants, and the oxygen release rate increased with the rising of the concentration of degradable materials in the solution. The summary of the methods in qualifying oxygen release by wetland plants demonstrated that variations existed among different measuring methods and even in the same measuring approach. The results would be helpful for understanding the contribution of plants in constructed wetlands toward actual wastewater treatment.

  8. Organic micropollutant removal in a full-scale surface flow constructed wetland fed with secondary effluent.

    PubMed

    Matamoros, Víctor; García, Joan; Bayona, Josep M

    2008-02-01

    The mass emission rate of 12 pollutants from a wastewater treatment plant (WWTP) secondary effluent into a small tributary of the River Besòs (northeastern Spain) was determined. The pollutants tested included pharmaceutical and personal care products (PPCPs) and herbicides. Furthermore, a 1-ha surface flow constructed wetland (SFCW) was evaluated for pollution removal. Whereas the low concentration values (ngL(-1)) of PPCP discharge into the tributary was comparable to inter- and intra-campaigns, herbicides and a veterinary drug (flunixin) exhibited a high variability in concentrations (microgL(-1)). Moreover, removal efficiencies were often higher than 90% for all compounds, with the exception of carbamazepine and clofibric acid (ca. 30-47%). As expected, a seasonal trend of pollutant removal in the wetland was observed for compounds with low biodegradation and moderate photodegradation rates (i.e. naproxen and diclofenac).

  9. Pilot treatment of olive pomace leachate by vertical-flow constructed wetland and electrochemical oxidation: an efficient hybrid process.

    PubMed

    Grafias, Petros; Xekoukoulotakis, Nikolaos P; Mantzavinos, Dionissios; Diamadopoulos, Evan

    2010-05-01

    A hybrid process comprising biological degradation in a vertical-flow constructed wetland (CW) and electrochemical oxidation over boron-doped diamond electrodes to decolorize, mineralize and detoxify a leachate from olive pomace processing (OPL) was investigated. Two alternative treatment schemes were compared: According to the first treatment scheme, OPL was treated by electrochemical oxidation followed by treatment in a constructed wetland pilot unit (CW-A). The second scheme comprised of treatment in a constructed wetland followed by electrochemical treatment (CW-B). The constructed wetlands units were planted with Phragmites australis (reeds) and were fed intermittently at organic loadings between 5 and 15 g COD m(-2) d(-1) and a residence time of 3 d. Electrochemical oxidation (EO) was performed for 360 min at 20 A. Treatment of OPL in the wetland at 15 g COD m(-2) d(-1) led to mean COD and color reduction of 86% and 77%, respectively; the wetland effluent with a COD of about 800 mg L(-1) was polished electrochemically for 360 min after which the overall COD and color removal of the combined process (i.e. CW-B/EO) was around 95%, while the final effluent was not toxic against the marine bacteria Vibrio fischeri. Electrochemical oxidation of the original OPL at COD values between 6250 and 14 100 mg L(-1) led to moderate COD and color reduction (i.e. less than 40%) through zero order kinetics. When this was coupled to constructed wetland post-treatment (i.e. EO/CW-A), the overall COD and color removal was 81% and 58%, respectively. The decreased efficiency may be assigned to the increased toxicity of the electrochemically treated effluent which was only partially removed in the natural treatment system. PMID:20199791

  10. Monitoring manganese diagenesis in a constructed wetland using continuous gradient gels

    SciTech Connect

    Edenborn, H.M.; Brickett, L.A.; Dvorak, D.H. . Pittsburgh Research Center); Edenborn, S.L. . Dept. of Biology)

    1992-01-01

    Constructed wetlands are used by coal mining companies to lower concentrations of dissolved Fe and Mn and reduce the cost of treating mine drainage chemically. Biological activity in wetlands assists in the removal of these metals by mediating their oxidation and reduction, and the intensity of these reactions is influenced strongly by seasonal fluctuations in wetlands have been developed empirically based on field observations, but few details are known about the spatial and temporal variation in Mn diagenesis within these wetlands. Biological activity within wetland sediments is known to be very heterogeneous, due in part to the complex composition of the composted organic materials used in wetland construction. This heterogeneity makes it difficult to assess the importance of specific diagenetic processes without taking large numbers of samples at great expense. In this study, continuous gradient gels (CGGs) were used to evaluate metal diagenesis spatially and seasonally within the sediments of a constructed wetland in northwestern PA receiving coal mine drainage. The CGGs were inexpensive to construct and were easy to deploy in the field. CGGs provided rapid and detailed information in the regions of stability of Mn oxides within the wetland sediment. The resulting data were mapped and used to assess the overall efficiency of constructed wetland design and the impact of Mn diagenesis in wetlands used to treat coal mine drainage.

  11. Phytoremediation of imazalil and tebuconazole by four emergent wetland plant species in hydroponic medium.

    PubMed

    Lv, Tao; Zhang, Yang; Casas, Mònica E; Carvalho, Pedro N; Arias, Carlos A; Bester, Kai; Brix, Hans

    2016-04-01

    Pollution from pesticide residues in aquatic environments is of increasing concern. Imazalil and tebuconazole, two commonly used systemic pesticides, are water contaminants that can be removed by constructed wetlands. However, the phytoremediation capability of emergent wetland plants for imazalil and tebuconazole, especially the removal mechanisms involved, is poorly understood. This study compared the removal of both pesticides by four commonly used wetland plants, Typha latifolia, Phragmites australis, Iris pseudacorus and Juncus effusus, and aimed to understand the removal mechanisms involved. The plants were individually exposed to an initial concentration of 10 mg/L in hydroponic solution. At the end of the 24-day study period, the tebuconazole removal efficiencies were relatively lower (25%-41%) than those for imazalil (46%-96%) for all plant species studied. The removal of imazalil and tebuconazole fit a first-order kinetics model, with the exception of tebuconazole removal in solutions with I. pseudacorus. Changes in the enantiomeric fraction for imazalil and tebuconazole were detected in plant tissue but not in the hydroponic solutions; thus, the translocation and degradation processes were enantioselective in the plants. At the end of the study period, the accumulation of imazalil and tebuconazole in plant tissue was relatively low and constituted 2.8-14.4% of the total spiked pesticide in each vessel. Therefore, the studied plants were able to not only take up the pesticides but also metabolise them.

  12. Phytoremediation of imazalil and tebuconazole by four emergent wetland plant species in hydroponic medium.

    PubMed

    Lv, Tao; Zhang, Yang; Casas, Mònica E; Carvalho, Pedro N; Arias, Carlos A; Bester, Kai; Brix, Hans

    2016-04-01

    Pollution from pesticide residues in aquatic environments is of increasing concern. Imazalil and tebuconazole, two commonly used systemic pesticides, are water contaminants that can be removed by constructed wetlands. However, the phytoremediation capability of emergent wetland plants for imazalil and tebuconazole, especially the removal mechanisms involved, is poorly understood. This study compared the removal of both pesticides by four commonly used wetland plants, Typha latifolia, Phragmites australis, Iris pseudacorus and Juncus effusus, and aimed to understand the removal mechanisms involved. The plants were individually exposed to an initial concentration of 10 mg/L in hydroponic solution. At the end of the 24-day study period, the tebuconazole removal efficiencies were relatively lower (25%-41%) than those for imazalil (46%-96%) for all plant species studied. The removal of imazalil and tebuconazole fit a first-order kinetics model, with the exception of tebuconazole removal in solutions with I. pseudacorus. Changes in the enantiomeric fraction for imazalil and tebuconazole were detected in plant tissue but not in the hydroponic solutions; thus, the translocation and degradation processes were enantioselective in the plants. At the end of the study period, the accumulation of imazalil and tebuconazole in plant tissue was relatively low and constituted 2.8-14.4% of the total spiked pesticide in each vessel. Therefore, the studied plants were able to not only take up the pesticides but also metabolise them. PMID:26841287

  13. Phytoremediation of Water Using Phragmites karka and Veteveria nigritana in Constructed Wetland.

    PubMed

    Badejo, Adedayo A; Sridhar, Mynepalli K C; Coker, Adewale O; Ndambuki, Julius M; Kupolati, Williams K

    2015-01-01

    Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy metals from industrial wastewater in a steel manufacturing company. A pilot Effluent Treatment Plant (ETP) consisting of equalization basin, two VSBCW basins and a storage tank was constructed. The VSBCW was constructed using 10-30 mm round granite for the different zones. This was overlaid by 200 mm deep granite and 150 mm washed sand with Phragmites karka, Vetiveria nigritana and Cana lilies as macrophytes. Irrigation of macrophytes using effluent from the industry was done after 3 months of planting and ETP monitored. Industrial wastewater samples were collected and analyzed for heavy metals such as zinc (Zn), lead (Pb), iron (Fe), manganese (Mn), magnesium (Mg) and chromium (Cr) to know the treatment efficiency of the ETP. Results indicated that the removal efficiencies of the VSBCW for Pb, Mg and Cr were 15.4%, 79.7% and 97.9% respectively. Fe and Mn were seen to increase by 1.8% and 33% respectively. The ETP using locally available macrophytes is effective in the phytoremediation of heavy metals, particularly Cr from the wastewater. PMID:26151537

  14. Phytoremediation of Water Using Phragmites karka and Veteveria nigritana in Constructed Wetland.

    PubMed

    Badejo, Adedayo A; Sridhar, Mynepalli K C; Coker, Adewale O; Ndambuki, Julius M; Kupolati, Williams K

    2015-01-01

    Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy metals from industrial wastewater in a steel manufacturing company. A pilot Effluent Treatment Plant (ETP) consisting of equalization basin, two VSBCW basins and a storage tank was constructed. The VSBCW was constructed using 10-30 mm round granite for the different zones. This was overlaid by 200 mm deep granite and 150 mm washed sand with Phragmites karka, Vetiveria nigritana and Cana lilies as macrophytes. Irrigation of macrophytes using effluent from the industry was done after 3 months of planting and ETP monitored. Industrial wastewater samples were collected and analyzed for heavy metals such as zinc (Zn), lead (Pb), iron (Fe), manganese (Mn), magnesium (Mg) and chromium (Cr) to know the treatment efficiency of the ETP. Results indicated that the removal efficiencies of the VSBCW for Pb, Mg and Cr were 15.4%, 79.7% and 97.9% respectively. Fe and Mn were seen to increase by 1.8% and 33% respectively. The ETP using locally available macrophytes is effective in the phytoremediation of heavy metals, particularly Cr from the wastewater.

  15. Wetland assessment of the effects of construction and operation of a depleteduranium hexafluoride conversion facility at the Portsmouth, Ohio, site.

    SciTech Connect

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF{sub 6} inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This wetland assessment has been prepared by DOE, pursuant to Executive Order 11990 (''Protection of Wetlands'') and DOE regulations for implementing this Executive Order as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [Compliance with Floodplain and Wetland Environmental Review Requirements]), to evaluate potential impacts to wetlands from the construction and operation of a conversion facility at the DOE Portsmouth site. Approximately 0.02 acre (0.009 ha) of a 0.08-acre (0.03-ha) palustrine emergent wetland would likely be eliminated by direct placement of fill material during facility construction at Location A. Portions of this wetland that are not filled may be indirectly affected by an altered

  16. Removal of the pharmaceuticals ibuprofen and iohexol by four wetland plant species in hydroponic culture: plant uptake and microbial degradation.

    PubMed

    Zhang, Yang; Lv, Tao; Carvalho, Pedro N; Arias, Carlos A; Chen, Zhanghe; Brix, Hans

    2016-02-01

    We aimed at assessing the effects of four wetland plant species commonly used in constructed wetland systems: Typha, Phragmites, Iris and Juncus for removing ibuprofen (IBU) and iohexol (IOH) from spiked culture solution and exploring the mechanisms responsible for the removal. IBU was nearly completely removed by all plant species during the 24-day experiment, whereas the IOH removal varied between 13 and 80 %. Typha and Phragmites were the most efficient in removing IBU and IOH, respectively, with first-order removal rate constants of 0.38 and 0.06 day(-1), respectively. The pharmaceuticals were taken up by the roots and translocated to the aerial tissues. However, at the end of the experiment, plant accumulation constituted only up to 1.1 and 5.7 % of the amount of IBU and IOH spiked initially. The data suggest that the plants mainly function by facilitating pharmaceutical degradation in the rhizosphere through release of root exudates. PMID:26490885

  17. Removal of the pharmaceuticals ibuprofen and iohexol by four wetland plant species in hydroponic culture: plant uptake and microbial degradation.

    PubMed

    Zhang, Yang; Lv, Tao; Carvalho, Pedro N; Arias, Carlos A; Chen, Zhanghe; Brix, Hans

    2016-02-01

    We aimed at assessing the effects of four wetland plant species commonly used in constructed wetland systems: Typha, Phragmites, Iris and Juncus for removing ibuprofen (IBU) and iohexol (IOH) from spiked culture solution and exploring the mechanisms responsible for the removal. IBU was nearly completely removed by all plant species during the 24-day experiment, whereas the IOH removal varied between 13 and 80 %. Typha and Phragmites were the most efficient in removing IBU and IOH, respectively, with first-order removal rate constants of 0.38 and 0.06 day(-1), respectively. The pharmaceuticals were taken up by the roots and translocated to the aerial tissues. However, at the end of the experiment, plant accumulation constituted only up to 1.1 and 5.7 % of the amount of IBU and IOH spiked initially. The data suggest that the plants mainly function by facilitating pharmaceutical degradation in the rhizosphere through release of root exudates.

  18. Early vegetational changes on a forested wetland constructed for mitigation

    USGS Publications Warehouse

    Perry, M.C.; Osenton, P.C.; Sibrel, C.B.

    1997-01-01

    Changes in vegetation were studied on 15 acres of a 35 acre forested wetland created as a mitigation site in Anne Arundel County, Maryland during 1994-96. Meter-square sampling on four different hydrologic elevations determined that grasses initially dominated the area, but decreased from 59 percent in 1994 to 51 percent in 1995 and 30 percent in 1996. Herbaceous non-grass plants (forbs) increased from 19 percent to 56 percent in the three-year period. Area with no plant cover decreased from 21 percent in 1994 to 11 percent in 1995, and 10 percent in 1996. Woody plants comprised 2 percent of the cover in 1994, increased to 4 percent in 1995, and remained at 4 percent in 1996. The increase of woody plants was mainly from natural regeneration (pioneer) plants. Monitoring of the transplanted trees and shrubs indicated 35 percent mortality and little growth of surviving plants. The pioneer woody plant forming most of the cover was black willow (Salix nigra). Differences in the vegetation were observed among the four elevations, although no differences were observed for the major vegetation classes between plots that were planted and those that were not planted with woody plants. Dominant grass species was redtop (Agrostis stolonifera), which comprised 51 percent of the cover in 1994 and 42 percent cover in 1995 and 23 percent in 1996. Other species that were common were bush clover (Lespedeza cuneata), Japanese clover (Lespedeza striata) and flat pea (Lathyrus sylvestris). All four of these dominant species were part of the original seed mixtures that were seeded on the site. A total of 134 species of plants was recorded on the site indicating a fairly diverse community for a newly established habitat.

  19. Dynamics of sulphur compounds in horizontal sub-surface flow laboratory-scale constructed wetlands treating artificial sewage.

    PubMed

    Wiessner, A; Rahman, K Z; Kuschk, P; Kästner, M; Jechorek, M

    2010-12-01

    The knowledge regarding the dynamics of sulphur compounds inside constructed wetlands is still insufficient. Experiments in planted (Juncus effusus) and unplanted horizontal sub-surface-flow laboratory-scale constructed wetlands fed with artificial wastewater were carried out to evaluate the sulphate reduction, the composition and dynamics of generated sulphur compounds, as well as the influence of carbon load and plants on processes of sulphur transformation. In planted and unplanted wetlands, the addition of organic carbon (TOC of about 120 mg L(-1)) immediately affected the transformation of up to 90% of the incoming sulphate (150 mg L(-1)), directing it mainly towards elemental sulphur (30%) and sulphide (8%). During this experimental period, nearly 52% of the transformed sulphate-sulphur was calculated to be immobilized inside the planted wetland and 66% inside the unplanted one. In subsequent experiments, the deficiency of organic carbon inside the planted wetlands favoured the decrease of elemental sulphur in the pore water coupled to retransformation of depot-sulphur to dissolved sulphate. Nearly 90% of the deposited and reduced sulphur was found to be reoxidized. In principle, the results indicate a substantial improvement of this reoxidation of sulphur by oxygen released by the helophytes. Surplus of organic carbon promotes the ongoing sulphate reduction and the stability of deposed and dissolved reduced sulphur compounds. In contrast, inside the unplanted control wetland, a relative stability of the formed sulphur depots and the generated amount of dissolved sulphur compounds including elemental sulphur could be observed independently of the different loading conditions.

  20. Phytoremediation of water contaminated with mercury using Typha domingensis in constructed wetland.

    PubMed

    Gomes, Marcos Vinícius Teles; de Souza, Roberto Rodrigues; Teles, Vinícius Silva; Araújo Mendes, Érica

    2014-05-01

    The presence of mercury in aquatic environments is a matter of concern by part of the scientific community and public health organizations worldwide due to its persistence and toxicity. The phytoremediation consists in a group of technologies based on the use of natural occurrence or genetically modified plants, in order to reduce, remove, break or immobilize pollutants and working as an alternative to replace conventional effluent treatment methods due to its sustainability - low cost of maintenance and energy. The current study provides information about a pilot scale experiment designed to evaluate the potential of the aquatic macrophyte Typha domingensis in a constructed wetland with subsurface flow for phytoremediation of water contaminated with mercury. The efficiency in the reduction of the heavy metal concentration in wetlands, and the relative metal sorption by the T. domingensis, varied according to the exposure time. The continued rate of the system was 7 times higher than the control line, demonstrating a better performance and reducing 99.6±0.4% of the mercury presents in the water contaminated. When compared to other species, the results showed that the T. domingensis demonstrated a higher mercury accumulation (273.3515±0.7234 mg kg(-1)) when the transfer coefficient was 7750.9864±569.5468 L kg(-1). The results in this present study shows the great potential of the aquatic macrophyte T. domingensis in constructed wetlands for phytoremediation of water contaminated with mercury.

  1. Prediction of water quality index in constructed wetlands using support vector machine.

    PubMed

    Mohammadpour, Reza; Shaharuddin, Syafiq; Chang, Chun Kiat; Zakaria, Nor Azazi; Ab Ghani, Aminuddin; Chan, Ngai Weng

    2015-04-01

    Poor water quality is a serious problem in the world which threatens human health, ecosystems, and plant/animal life. Prediction of surface water quality is a main concern in water resource and environmental systems. In this research, the support vector machine and two methods of artificial neural networks (ANNs), namely feed forward back propagation (FFBP) and radial basis function (RBF), were used to predict the water quality index (WQI) in a free constructed wetland. Seventeen points of the wetland were monitored twice a month over a period of 14 months, and an extensive dataset was collected for 11 water quality variables. A detailed comparison of the overall performance showed that prediction of the support vector machine (SVM) model with coefficient of correlation (R(2)) = 0.9984 and mean absolute error (MAE) = 0.0052 was either better or comparable with neural networks. This research highlights that the SVM and FFBP can be successfully employed for the prediction of water quality in a free surface constructed wetland environment. These methods simplify the calculation of the WQI and reduce substantial efforts and time by optimizing the computations.

  2. AIRBORNE HYPERSPECTRAL IDENTIFICATION OF INVASIVE AND OPPORTUNISTIC WETLANDS PLANT SPECIES

    EPA Science Inventory

    Coastal wetlands are among the most fragmented and disturbed ecosystems and the Great Lakes are no exception. One possible result is the observed increase in the presence and dominance of invasive and other opportunistic plant species, such as the common reed (Phragmites australi...

  3. Carbon sequestration in a surface flow constructed wetland after 12 years of swine wastewater treatment.

    PubMed

    Reddy, Gudigopuram B; Raczkowski, Charles W; Cyrus, Johnsely S; Szogi, Ariel

    2016-01-01

    Constructed wetlands used for the treatment of swine wastewater may potentially sequester significant amounts of carbon. In past studies, we evaluated the treatment efficiency of wastewater in a marsh-pond-marsh design wetland system. The functionality of this system was highly dependent on soil carbon content and organic matter turnover rate. To better understand system performance and carbon dynamics, we measured plant dry matter, decomposition rates and soil carbon fractions. Plant litter decomposition rate was 0.0052 g day(-1) (±0.00119 g day(-1)) with an estimated half-life of 133 days. The detritus layer accumulated over the soil surface had much more humin than other C fractions. In marsh areas, soil C extracted with NaOH had four to six times higher amounts of humic acid, fulvic acid and humin than soil C extracted by cold and hot water, HCl/HF, and Na pyruvate. In the pond area, humic acid, fulvic acid and humin content were two to four times lower than in the marsh area. More soil C and N was found in the marsh area than in the pond area. These wetlands proved to be large sinks for stable C forms.

  4. Applying solubilization treatment to reverse clogging in laboratory-scale vertical flow constructed wetlands.

    PubMed

    Guofen, Hua; Wei, Zhu; Lianfang, Zhao; Yunhui, Zhang

    2010-01-01

    Substrate clogging is characterized as a frequently occurring operational problem for subsurface-flow constructed wetlands. The application of solubilization treatment to reduce clogging was tested in lab-scaled setups to provide a promising solution. The performance of solubilization treatment on reducing clogging and the related effects on plants and biofilms in the wetland system were investigated in this paper. The results showed that the infiltration rate and available porosity of wetland substrate increased as a function of increased dosage of NaOH, HCl, NaClO, and detergent, respectively. Among the four solvents, it appeared that NaClO had the most obvious effects on reducing clogging and the infiltration rate and effective porosity recovered to 69% of the original condition. The two possible reasons for solubilization were the flocculents' structure of the clogs was broken up or parts of the organic clogs were dissolved. The function of adding NaOH and NaClO was to dissolve the protein and polysaccharides of the organic clogs; the function of adding HCl was to release the anaerobic gas wrapped in the organic clogs. Furthermore, experiments results also showed that the solubilized solvents did not demonstrate a long-term negative effect on plants and biofilms.

  5. Carbon sequestration in a surface flow constructed wetland after 12 years of swine wastewater treatment.

    PubMed

    Reddy, Gudigopuram B; Raczkowski, Charles W; Cyrus, Johnsely S; Szogi, Ariel

    2016-01-01

    Constructed wetlands used for the treatment of swine wastewater may potentially sequester significant amounts of carbon. In past studies, we evaluated the treatment efficiency of wastewater in a marsh-pond-marsh design wetland system. The functionality of this system was highly dependent on soil carbon content and organic matter turnover rate. To better understand system performance and carbon dynamics, we measured plant dry matter, decomposition rates and soil carbon fractions. Plant litter decomposition rate was 0.0052 g day(-1) (±0.00119 g day(-1)) with an estimated half-life of 133 days. The detritus layer accumulated over the soil surface had much more humin than other C fractions. In marsh areas, soil C extracted with NaOH had four to six times higher amounts of humic acid, fulvic acid and humin than soil C extracted by cold and hot water, HCl/HF, and Na pyruvate. In the pond area, humic acid, fulvic acid and humin content were two to four times lower than in the marsh area. More soil C and N was found in the marsh area than in the pond area. These wetlands proved to be large sinks for stable C forms. PMID:27191573

  6. Hydraulics of sub-superficial flow constructed wetlands in semi arid climate conditions.

    PubMed

    Ranieri, E

    2003-01-01

    This paper reports the evaluation of the hydraulics of two constructed wetland (cw(s)) plants located in Apulia (the South Eastern Italy region characterized by semi arid climate conditions). These fields were planted with Phragmites australis hydrophytes and are supplied with local secondary wastewater municipal treatment plant effluent. Each plant--Kickuth Root-Zone method based--covers an area of approx. 2,000 m2. The evapotranspiration phenomenon has been evaluated within perforated tubes fixed to the field bottom and very high values--up to 40 mm/d--were found. Hydraulic conductivity has been evaluated by in situ measurements at different field points. Hydraulic gradients and the piezometric curve within the field are also reported. PMID:12793661

  7. Hydraulics of sub-superficial flow constructed wetlands in semi arid climate conditions.

    PubMed

    Ranieri, E

    2003-01-01

    This paper reports the evaluation of the hydraulics of two constructed wetland (cw(s)) plants located in Apulia (the South Eastern Italy region characterized by semi arid climate conditions). These fields were planted with Phragmites australis hydrophytes and are supplied with local secondary wastewater municipal treatment plant effluent. Each plant--Kickuth Root-Zone method based--covers an area of approx. 2,000 m2. The evapotranspiration phenomenon has been evaluated within perforated tubes fixed to the field bottom and very high values--up to 40 mm/d--were found. Hydraulic conductivity has been evaluated by in situ measurements at different field points. Hydraulic gradients and the piezometric curve within the field are also reported.

  8. Microbial populations and decomposition activity in three subsurface flow constructed wetlands

    SciTech Connect

    Hatano, K.; Trettin, C.C.; House, C.H.; Wollum, A.G. II

    1991-12-31

    Metabolic activity of microorganisms is the primary mechanism for organic matter degradation in constructed wetlands. However, the occurrence and abundance of different types of microorganisms responsible for degradation reactions has not been widely studied. The objective of this paper is to characterize the distribution and abundance of microorganisms in three constructed wetlands and evaluate their potent decomposition activity.

  9. Microbial populations and decomposition activity in three subsurface flow constructed wetlands

    SciTech Connect

    Hatano, K.; Trettin, C.C.; House, C.H.; Wollum, A.G. II )

    1991-01-01

    Metabolic activity of microorganisms is the primary mechanism for organic matter degradation in constructed wetlands. However, the occurrence and abundance of different types of microorganisms responsible for degradation reactions has not been widely studied. The objective of this paper is to characterize the distribution and abundance of microorganisms in three constructed wetlands and evaluate their potent decomposition activity.

  10. Effect of loading rate on performance of constructed wetlands treating an anaerobic supernatant.

    PubMed

    Chazarenc, F; Maltais-Landry, G; Troesch, S; Comeau, Y; Brisson, J

    2007-01-01

    The effect of organic loading, season and plant species on the treatment of fish farm effluent was tested using three-year old mesocosm wetland systems. During one year, nine 1 m2 mesocosms (horizontal subsurface flow), located in a controlled greenhouse environment, were fed with a reconstituted fish farm effluent containing a high fraction of soluble components (1,600 microS/cm and in mg/L: 230 +/- 80 COD, 179 +/- 60 sCOD, 100 +/- 40 TSS, 37 +/- 7 TKN, 14 +/- 2 TP). Combinations of three hydraulic loading rates (30, 60 and 90 L.m(-2) d(-1)) and two plant species (Phragmites australis, Typha angustifolia) and an unplanted control were tested for treatment performance and hydraulic behaviour. Loadings higher than 15 g COD m(-2) d(-1) resulted in a net decrease of hydraulic performances (generation of short circuiting) coupled with low TKN removal. Maximal TKN removal rates (summer: 1.2, winter: 0.6 g.m(-2) d(-1)) were reached in planted units. In all mesocosms, phosphorus was removed during summer (maximal removal rate: 0.3 g TP m(-2) d(-1)) and was released in winter (release rate = approximately half of summer removal rate). This study confirmed that constructed wetlands are susceptible to clogging when treating anaerobic storage tank supernatant rich in highly biodegradable compounds. Contributions of plants to hydraulic efficiency were mainly observed in summer, associated with high evapotranspiration rates. Both plant species gave a similar removal efficiency for all pollutants.

  11. Occurrence and removal of estrogens, progesterone and testosterone in three constructed wetlands treating municipal sewage in the Czech Republic.

    PubMed

    Vymazal, Jan; Březinová, Tereza; Koželuh, Milan

    2015-12-01

    Estrogenic hormones, progesterone and testosterone are endocrine-disrupting chemicals and their presence in aquatic environments represents a potentially adverse environmental and public health impact. There is a considerable amount of information about removal of estrogens, progesterone and testosterone in conventional wastewater treatment plants, namely activated sludge systems. However, the information about removal of these compounds in constructed wetlands is very limited. Three constructed wetlands with horizontal subsurface flow in the Czech Republic have been selected to evaluate removal of estrogens (estrone, estriol, 17β-estradiol, 17α-ethinylestradiol), testosterone and progesterone. Monitored constructed wetlands for 100, 150 and 200 PE have been in operation for more than 10 years and all systems exhibit very high treatment efficiency for organics and suspended solids. The results indicate that removal of all estrogens, progesterone and testosterone was high and only estrone was found in the outflow from one constructed wetland in concentrations above the limit of quantification 1 ng l(-1). The limits of quantification for other estrogens, i.e., 10 ng l(-1) for estriol, 1 ng l(-1) for 17β-estradiol and 2 ng l(-1) for 17α-ethinylestradiol were not exceeded in the outflow of all monitored constructed wetlands. Also, for progesterone and testosterone, all outflow concentrations were below the LOQ of 0.5 ng l(-1). The results indicated that constructed wetlands with horizontal subsurface flow are a promising technology for elimination of estrogens, progesterone and testosterone from municipal sewage but more information is needed to confirm this finding. PMID:26247691

  12. Occurrence and removal of estrogens, progesterone and testosterone in three constructed wetlands treating municipal sewage in the Czech Republic.

    PubMed

    Vymazal, Jan; Březinová, Tereza; Koželuh, Milan

    2015-12-01

    Estrogenic hormones, progesterone and testosterone are endocrine-disrupting chemicals and their presence in aquatic environments represents a potentially adverse environmental and public health impact. There is a considerable amount of information about removal of estrogens, progesterone and testosterone in conventional wastewater treatment plants, namely activated sludge systems. However, the information about removal of these compounds in constructed wetlands is very limited. Three constructed wetlands with horizontal subsurface flow in the Czech Republic have been selected to evaluate removal of estrogens (estrone, estriol, 17β-estradiol, 17α-ethinylestradiol), testosterone and progesterone. Monitored constructed wetlands for 100, 150 and 200 PE have been in operation for more than 10 years and all systems exhibit very high treatment efficiency for organics and suspended solids. The results indicate that removal of all estrogens, progesterone and testosterone was high and only estrone was found in the outflow from one constructed wetland in concentrations above the limit of quantification 1 ng l(-1). The limits of quantification for other estrogens, i.e., 10 ng l(-1) for estriol, 1 ng l(-1) for 17β-estradiol and 2 ng l(-1) for 17α-ethinylestradiol were not exceeded in the outflow of all monitored constructed wetlands. Also, for progesterone and testosterone, all outflow concentrations were below the LOQ of 0.5 ng l(-1). The results indicated that constructed wetlands with horizontal subsurface flow are a promising technology for elimination of estrogens, progesterone and testosterone from municipal sewage but more information is needed to confirm this finding.

  13. Temporal variation of nitrogen balance within constructed wetlands treating slightly polluted water using a stable nitrogen isotope experiment.

    PubMed

    Zhang, Wanguang; Lei, Qiongye; Li, Zhengkui; Han, Huayang

    2016-02-01

    Slightly polluted water has become one of the main sources of nitrogen contaminants in recent years, for which constructed wetlands (CW) is a typical and efficient treatment. However, the knowledge about contribution of individual nitrogen removal pathways and nitrogen balance in constructed wetlands is still limited. In this study, a stable-isotope-addition experiment was performed in laboratory-scale constructed wetlands treating slightly polluted water to determine quantitative contribution of different pathways and temporal variation of nitrogen balance using Na(15)NO3 as tracer. Microbial conversion and substrate retention were found to be the dominant pathways in nitrogen removal contributing 24.4-79.9 and 8.9-70.7 %, respectively, while plant contributed only 4.6-11.1 % through direct assimilation but promoted the efficiency of other pathways. In addition, microbial conversion became the major way to remove N whereas nitrogen retained in substrate at first was gradually released to be utilized by microbes and plants over time. The findings indicated that N2 emission representing microbial conversion was not only the major but also permanent nitrogen removal process, thus keeping a high efficiency of microbial conversion is important for stable and efficient nitrogen removal in constructed wetlands.

  14. Temporal variation of nitrogen balance within constructed wetlands treating slightly polluted water using a stable nitrogen isotope experiment.

    PubMed

    Zhang, Wanguang; Lei, Qiongye; Li, Zhengkui; Han, Huayang

    2016-02-01

    Slightly polluted water has become one of the main sources of nitrogen contaminants in recent years, for which constructed wetlands (CW) is a typical and efficient treatment. However, the knowledge about contribution of individual nitrogen removal pathways and nitrogen balance in constructed wetlands is still limited. In this study, a stable-isotope-addition experiment was performed in laboratory-scale constructed wetlands treating slightly polluted water to determine quantitative contribution of different pathways and temporal variation of nitrogen balance using Na(15)NO3 as tracer. Microbial conversion and substrate retention were found to be the dominant pathways in nitrogen removal contributing 24.4-79.9 and 8.9-70.7 %, respectively, while plant contributed only 4.6-11.1 % through direct assimilation but promoted the efficiency of other pathways. In addition, microbial conversion became the major way to remove N whereas nitrogen retained in substrate at first was gradually released to be utilized by microbes and plants over time. The findings indicated that N2 emission representing microbial conversion was not only the major but also permanent nitrogen removal process, thus keeping a high efficiency of microbial conversion is important for stable and efficient nitrogen removal in constructed wetlands. PMID:26438366

  15. [Optimization of aerobic/anaerobic subsurface flow constructed wetlands].

    PubMed

    Li, Feng-Min; Shan, Shi; Li, Yuan-Yuan; Li, Yang; Wang, Zheng-Yu

    2012-02-01

    Previous studies showed that setting aerobic and anaerobic paragraph segments in the subsurface constructed wetlands (SFCWs) can improve the COD, NH4(+)-N, and TN removal rate, whereas the oxygen enrichment environment which produced by the artificial aeration could restrain the NO3(-)-N and NO2(-)-N removal process, and to a certain extent, inhibit the denitrification in SFCWs Therefore, in this research the structure and technology of SFCW with aerobic and anaerobic paragraph segments were optimized, by using the multi-point water inflow and setting the corresponding section for the extra pollutant removal. Results showed that with the hydraulic load of 0.06 m3 x (m2 x d)(-1), the COD, NH4(+)-N and TN removal efficiencies in the optimized SFCW achieved 91.6%, 100% and 87.7% respectively. COD/N increased to 10 speedily after the inflow supplement. The multi-point water inflow could add carbon sources, and simultaneously maximum utilization of wetland to remove pollutants. The optimized SFCW could achieve the purposes of purification process optimization, and provide theoretical basis and application foundation for improving the total nitrogen removal efficiency.

  16. Constructed Wetlands for Treatment of Organic and Engineered Nanomaterial Contaminants of Emerging Concerns (WaterRF Report 4334)

    EPA Science Inventory

    The goal of this project was to determine hydraulic and carbon loading rates for constructed wetlands required for achieving different levels of organic and nanomaterial contaminants of emerging concern (CECs) removal in constructed wetlands. Specific research objectives included...

  17. [Diversity of plant in Jiaxing Shijiuyang ecological wetland for drinking water during operation].

    PubMed

    Shen, Ya-Qiang; Wei, Hong-Bin; Cheng, Wang-Da; Zhang, Hong-Mei; Wang, Wei-Dong; Yin, Cheng-Qing

    2011-10-01

    The Shijiuyang ecological wetland for drinking water of Jiaxing City, Zhejiang Province is one of the biggest constructed wetlands for water resource protection in China. To ensure a deep understanding of the present status of the wetland vegetation of Shijiuyang ecological wetland which has been run for 2.5 years and provide support for the vegetation management of ecological wetland, systematic investigation was carried out by using plot method and quadrat method in October to November, 2010. The species composition, dynamics of plant diversity and the biomass production during operation were analyzed. Altogether 70 species belonging to 28 families and 62 genera were recorded. Among them, there were 26 wetland plants, 20 mesophytes, 14 emergent, 4 submerged, 6 floating ones. Compared with the preliminary stage, the species numbers of wetland plants increased significantly from 15 species to 70 species. The spatial pattern of riparian species diversity was examined by adopting the Simpson index and Shannon-Wiener index as species diversity indices. The results showed that the riparian species diversity was higher in the west of the Beijiaohe river (Simpson index = 0.468 3, Shannon-Wiener index = 0.835 2) than that in the south of the Dongsheng Road (Simpson index = 0.357 6, Shannon-Wiener index = 0.660 4). The analyses of quantitative characteristics of wetland vegetation showed that the plants in the root-channel purification zone in the south of the Dongsheng Road grew better than those in the west of the Beijiaohe river. With regard to the riparian vegetation, the riparian plants in the west of the Beijiaohe river were more abundant. The mean biomass production (dry weight) in the root-channel purification zone was 1.73 kg x m(-2) and the total area was 9.12 x 10(4) m2, so the total biomass production was estimated to be 157.8 t. In the same way, the mean riparian vegetation biomass production(dry weight) was 0.83 kg x m(-2) and the total vegetation area was 3

  18. A Constructed Freshwater Wetland Shows Signs of Declining Net Ecosystem Exchange

    NASA Astrophysics Data System (ADS)

    Anderson, F. E.; Bergamaschi, B. A.; Windham-Myers, L.; Byrd, K. B.; Drexler, J. Z.; Fujii, R.

    2014-12-01

    The USGS constructed a freshwater-wetland complex on Twitchell Island in the Sacramento-San Joaquin Delta (Delta), California, USA, in 1997 and maintained it until 2012 to investigate strategies for biomass accretion and reduction of oxidative soil loss. We studied an area of the wetland complex covered mainly by dense patches of hardstem bulrush (Schoenoplectus acutus) and cattails (Typha spp.), with smaller areas of floating and submerged vegetation, that was maintained at an average depth of 55 cm. Using eddy covariance measurements of carbon and energy fluxes, we found that the combination of water management and the region's Mediterranean climate created conditions where peak growing season daily means of net ecosystem exchange (NEE) reached -45 gCO2 m-2 d-1 and averaged around -30 gCO2 m-2 d-1 between 2002 through 2004. However, when measurements resumed in 2010, NEE rates were a fraction of the rates previously measured, approximately -6 gCO2 m-2 d-1. Interestingly, NEE rates in 2011 doubled compared to 2010 (-13 gCO2 m-2 d-1). Methane fluxes, collected in 2010 to assess a complete atmospheric carbon budget, were positive throughout the year, with daily mean flux values ranging from 50 to 300 mg CH4 m-2 d-1. As a result, methane flux reduced NEE values by approximately one-third, and when the global warming potential was considered, the wetland became a net global warming potential source. We found that carbon cycling in a constructed wetland is complex and can change over annual and decadal timescales. We investigated possible reasons for differences between flux measurements from 2002 to 2004 and those from 2010 and 2011: (1) changes in methodology, (2) differences in weather conditions, (3) differences in gross primary productivity relative to respiration rates, and (4) the amount of living plant tissue relative to brown accumulations of senesced plant litter. We hypothesize that large mats of senesced material within the flux footprint could have

  19. Specifically Designed Constructed Wetlands: A Novel Treatment Approach for Scrubber Wastewater

    SciTech Connect

    John H. Rodgers Jr; James W. Castle; Chris Arrington: Derek Eggert; Meg Iannacone

    2005-09-01

    A pilot-scale wetland treatment system was specifically designed and constructed at Clemson University to evaluate removal of mercury, selenium, and other constituents from flue gas desulfurization (FGD) wastewater. Specific objectives of this research were: (1) to measure performance of a pilot-scale constructed wetland treatment system in terms of decreases in targeted constituents (Hg, Se and As) in the FGD wastewater from inflow to outflow; (2) to determine how the observed performance is achieved (both reactions and rates); and (3) to measure performance in terms of decreased bioavailability of these elements (i.e. toxicity of sediments in constructed wetlands and toxicity of outflow waters from the treatment system). Performance of the pilot-scale constructed wetland treatment systems was assessed using two criteria: anticipated NPDES permit levels and toxicity evaluations using two sentinel toxicity-testing organisms (Ceriodaphnia dubia and Pimephales promelas). These systems performed efficiently with varied inflow simulations of FGD wastewaters removing As, Hg, and Se concentrations below NPDES permit levels and reducing the toxicity of simulated FGD wastewater after treatment with the constructed wetland treatment systems. Sequential extraction procedures indicated that these elements (As, Hg, and Se) were bound to residual phases within sediments of these systems, which should limit their bioavailability to aquatic biota. Sediments collected from constructed wetland treatment systems were tested to observe toxicity to Hyalella azteca or Chironomus tetans. Complete survival (100%) was observed for H. azteca in all cells of the constructed wetland treatment system and C. tentans had an average of 91% survival over the three treatment cells containing sediments. Survival and growth of H. azteca and C. tentans did not differ significantly between sediments from the constructed wetland treatment system and controls. Since the sediments of the constructed

  20. Treatment of laboratory wastewater in a tropical constructed wetland comparing surface and subsurface flow.

    PubMed

    Meutia, A A

    2001-01-01

    Wastewater treatment by constructed wetland is an appropriate technology for tropical developing countries like Indonesia because it is inexpensive, easily maintained, and has environmentally friendly and sustainable characteristics. The aim of the research is to examine the capability of constructed wetlands for treating laboratory wastewater at our Center, to investigate the suitable flow for treatment, namely vertical subsurface or horizontal surface flow, and to study the effect of the seasons. The constructed wetland is composed of three chambered unplanted sedimentation tanks followed by the first and second beds, containing gravel and sand, planted with Typha sp.; the third bed planted with floating plant Lemna sp.; and a clarifier with two chambers. The results showed that the subsurface flow in the dry season removed 95% organic carbon (COD) and total phosphorus (T-P) respectively, and 82% total nitrogen (T-N). In the transition period from the dry season to the rainy season, COD removal efficiency decreased to 73%, T-N increased to 89%, and T-P was almost the same as that in the dry season. In the rainy season COD and T-N removal efficiencies increased again to 95% respectively, while T-P remained unchanged. In the dry season, COD and T-P concentrations in the surface flow showed that the removal efficiencies were a bit lower than those in the subsurface flow. Moreover, T-N removal efficiency was only half as much as that in the subsurface flow. However, in the transition period, COD removal efficiency decreased to 29%, while T-N increased to 74% and T-P was still constant, around 93%. In the rainy season, COD and T-N removal efficiencies increased again to almost 95%. On the other hand, T-P decreased to 76%. The results show that the constructed wetland is capable of treating the laboratory wastewater. The subsurface flow is more suitable for treatment than the surface flow, and the seasonal changes have effects on the removal efficiency.

  1. Treatment of laboratory wastewater in a tropical constructed wetland comparing surface and subsurface flow.

    PubMed

    Meutia, A A

    2001-01-01

    Wastewater treatment by constructed wetland is an appropriate technology for tropical developing countries like Indonesia because it is inexpensive, easily maintained, and has environmentally friendly and sustainable characteristics. The aim of the research is to examine the capability of constructed wetlands for treating laboratory wastewater at our Center, to investigate the suitable flow for treatment, namely vertical subsurface or horizontal surface flow, and to study the effect of the seasons. The constructed wetland is composed of three chambered unplanted sedimentation tanks followed by the first and second beds, containing gravel and sand, planted with Typha sp.; the third bed planted with floating plant Lemna sp.; and a clarifier with two chambers. The results showed that the subsurface flow in the dry season removed 95% organic carbon (COD) and total phosphorus (T-P) respectively, and 82% total nitrogen (T-N). In the transition period from the dry season to the rainy season, COD removal efficiency decreased to 73%, T-N increased to 89%, and T-P was almost the same as that in the dry season. In the rainy season COD and T-N removal efficiencies increased again to 95% respectively, while T-P remained unchanged. In the dry season, COD and T-P concentrations in the surface flow showed that the removal efficiencies were a bit lower than those in the subsurface flow. Moreover, T-N removal efficiency was only half as much as that in the subsurface flow. However, in the transition period, COD removal efficiency decreased to 29%, while T-N increased to 74% and T-P was still constant, around 93%. In the rainy season, COD and T-N removal efficiencies increased again to almost 95%. On the other hand, T-P decreased to 76%. The results show that the constructed wetland is capable of treating the laboratory wastewater. The subsurface flow is more suitable for treatment than the surface flow, and the seasonal changes have effects on the removal efficiency. PMID:11804141

  2. Effects of the substrate depth on purification performance of a hybrid constructed wetland treating domestic sewage.

    PubMed

    Ren, Yong-Xiang; Zhang, Hai; Wang, Chao; Yang, Yong-Zhe; Qin, Zhen; Ma, Yun

    2011-01-01

    The depth of substrate in constructed wetlands (CWs) has a significant effect on the construction investment and the purification performance of CWs. In this study, a pilot scale CW system was operated in a domestic sewage treatment plant in Xi'an, China. The experimental systems included three-series CWs systems with substrate depths of 0.1m, 0.3 m and 0.6 m, respectively. Each series was composed of a hydroponic ditch, a horizontal subsurface flow CW and a vertical flow CW. The effluent from the primary clarifier in the sewage treatment plant was intermittently conducted to the wetlands at a flow rate of 0.3 m(3)/d. The hydraulic loading rate of each CWs system was regulated at 0.1 m(3)/m(2).d and the hydraulic retention time was 3 days. Canna indica L. was planted both in the hydroponic ditches and the CWs systems. Results showed that the highest removal efficiency of NH(+)(4)-N and TP was obtained in the hybrid CW with 0.1 m substrate depth. The average removal efficiency for NH(+)(4)-N and TP were 90.6 % and 80.0 %, respectively. The highest average removal efficiency of COD was obtained in hybrid CWs system with 0.6 m substrate depth. Therefore, a simultaneous removal of COD and nutrients can be achieved through the combination of different wetlands using different substrate depths. In addition, the substrate depth presents significant effects on the concentration of DO and root growth characteristics of canna in the system. As a result, the highest concentration of DO (>2 mg/L) and the highest amount of roots production were achieved in the 0.1 m substrate depth horizontal and vertical flow CWs.

  3. ACCURACY ASSESSMENTS OF AIRBORNE HYSPERSPECTRAL DATA FOR MAPPING OPPORTUNISTIC PLANT SPECIES IN FRESHWATER COASTAL WETLANDS

    EPA Science Inventory

    Airbome hyperspectral data were used to detect dense patches of Phragmites australis, a native opportunist plant species, at the Pointe Mouillee coastal wetland complex (Wayne and Monroe Counties, Michigan). This study provides initial results from one of thirteen coastal wetland...

  4. High plant diversity in Oregon tidal wetlands and multiple threats to its persistence

    EPA Science Inventory

    Tidal wetlands in the Pacific Northwest occur in coastal estuaries differing widely in size, relative freshwater inputs, and degree of watershed development. To better understand patterns of plant diversity in tidal wetlands across the region and potential climate change effects ...

  5. Performance of a single stage vertical flow constructed wetland system treating raw domestic sewage in Brazil.

    PubMed

    Lana, L C O; Moraes, D C; von Sperling, M; Morato, M L N; Vasconcellos, G R; Paraense, M O; Moreira, T P A

    2013-01-01

    This study investigated the behaviour of two intermittently fed vertical flow constructed wetlands (one planted with Tifton 85 and the other unplanted) working in parallel, treating raw municipal sewage in Brazil for a population equivalent around 100 inhabitants. Based on a monitoring programme of over 2 years, the following items were evaluated: influence of batch frequency and the presence of Tifton 85 on the wetlands performance in terms of several physico-chemical and biological constituents. The unit with plants performed better than the one without, indicating a positive influence of the presence of plants. More attachment by total and volatile solids and larger amount of bacteria involved in the nitrogen cycle were observed in the planted filter medium, which can explain its higher nitrification and solids removal. The application of a smaller influent volume with a higher batch frequency improved the performance of both units. No signs of medium clogging have been observed in both units. The system simplicity and the good removal efficiency of organic matter, suspended solids, ammonia and helminth eggs indicate its high applicability in small communities in developing countries such as Brazil.

  6. Phytoremediation of wastewater with Limnocharis flava, Thalia geniculata and Typha latifolia in constructed wetlands.

    PubMed

    Anning, Alexander K; Korsah, Percy E; Addo-Fordjour, Patrick

    2013-01-01

    Phytoremediation is thought to be the most sustainable wastewater treatment option for developing countries. However, its application is often limited by unavailability of suitable candidate species. In the present study, the potentials of Limnocharis flava, Thalia geniculata and Typha latifolia for remediation of heavy metal contaminated wastewater with a constructed wetland system were evaluated. The wetland consisted of three treatment lines each planted with sufficient and equal number of a species. Duplicate plant and water samples were collected bi-monthly and analyzed for Fe, Cu, Zn, Pb, and Hg using the atomic absorption spectrophotometer over a six month period. Bioaccumulation rates generally increased over time and varied among plants for these metals, with Fe (456-1549 mg kg1 roots; 20-183 mg kg(-1) shoot) being the most sequestered and Pb (1.2-7.6 mg kg(-1) roots; 1.55-3.95 mg kg(-1) shoot) the least. Translocation factors differed among the species but generally remained stable over time. L flava showed potential for hyperaccumulating Hg. Removal efficiencies varied for the studied metals (approximately 20-77 %) and were generally related to metal uptake by the plants. These results demonstrate the suitability of the species for phytoremediation, and the usefulness of the technique as an option for improving irrigation water quality in Ghana. PMID:23488171

  7. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands.

    PubMed

    Seeger, Eva M; Kuschk, Peter; Fazekas, Helga; Grathwohl, Peter; Kaestner, Matthias

    2011-12-01

    In this pilot-scale constructed wetland (CW) study for treating groundwater contaminated with benzene, MTBE, and ammonia-N, the performance of two types of CWs (a wetland with gravel matrix and a plant root mat) was investigated. Hypothesized stimulative effects of filter material additives (charcoal, iron(III)) on pollutant removal were also tested. Increased contaminant loss was found during summer; the best treatment performance was achieved by the plant root mat. Concentration decrease in the planted gravel filter/plant root mat, respectively, amounted to 81/99% for benzene, 17/82% for MTBE, and 54/41% for ammonia-N at calculated inflow loads of 525/603 mg/m(2)/d, 97/112 mg/m(2)/d, and 1167/1342 mg/m(2)/d for benzene, MTBE, and ammonia-N. Filter additives did not improve contaminant depletion, although sorption processes were observed and elevated iron(II) formation indicated iron reduction. Bacterial and stable isotope analysis provided evidence for microbial benzene degradation in the CW, emphasizing the promising potential of this treatment technique.

  8. Phytoremediation of wastewater with Limnocharis flava, Thalia geniculata and Typha latifolia in constructed wetlands.

    PubMed

    Anning, Alexander K; Korsah, Percy E; Addo-Fordjour, Patrick

    2013-01-01

    Phytoremediation is thought to be the most sustainable wastewater treatment option for developing countries. However, its application is often limited by unavailability of suitable candidate species. In the present study, the potentials of Limnocharis flava, Thalia geniculata and Typha latifolia for remediation of heavy metal contaminated wastewater with a constructed wetland system were evaluated. The wetland consisted of three treatment lines each planted with sufficient and equal number of a species. Duplicate plant and water samples were collected bi-monthly and analyzed for Fe, Cu, Zn, Pb, and Hg using the atomic absorption spectrophotometer over a six month period. Bioaccumulation rates generally increased over time and varied among plants for these metals, with Fe (456-1549 mg kg1 roots; 20-183 mg kg(-1) shoot) being the most sequestered and Pb (1.2-7.6 mg kg(-1) roots; 1.55-3.95 mg kg(-1) shoot) the least. Translocation factors differed among the species but generally remained stable over time. L flava showed potential for hyperaccumulating Hg. Removal efficiencies varied for the studied metals (approximately 20-77 %) and were generally related to metal uptake by the plants. These results demonstrate the suitability of the species for phytoremediation, and the usefulness of the technique as an option for improving irrigation water quality in Ghana.

  9. Efficiencies of freshwater and estuarine constructed wetlands for phenolic endocrine disruptor removal in Taiwan.

    PubMed

    Hsieh, Chi-Ying; Yang, Lei; Kuo, Wen-Chien; Zen, Yi-Peng

    2013-10-01

    We examined the distribution and removal efficiencies of phenolic endocrine disruptors (EDs), namely nonylphenol diethoxylates (NP2EO), nonylphenol monoethoxylates (NP1EO), nonylphenol (NP), and octylphenol (OP), in wastewater treated by estuarine and freshwater constructed wetland systems in Dapeng Bay National Scenic Area (DBNSA) and along the Dahan River in Taiwan. Water samples were taken bimonthly at 30 sites in three estuarine constructed wetlands (Datan, Pengcun and Linbian right bank (A and B)) in DBNSA, for eight sampling campaigns. The average removal efficiencies were in the range of 3.13-97.3% for wetlands in DBNSA. The highest average removal occurred in the east inlet to the outlet of the Tatan wetland. The most frequently detected compound was OP (57.7%), whose concentration was up to 1458.7 ng/L in DBNSA. NP was seen in only 20.5% of the samples. The temporal variation of EDs showed a decrease across seasons, where summer>spring>winter>autumn in these constructed wetlands. The removal efficiencies of EDs by estuarine wetlands, in decreasing order, were Datan>Pengcun>Linbian right bank in DBNSA. Water samples collected at 18 sites in three freshwater constructed wetlands (Daniaopi, Hsin-Hai I, and Hsin-Hai II) along the riparian area of Dahan River. NP2EO was the most abundant compound, with a concentration of up to 11,200 ng/L. Removal efficiencies ranged from 55% to 91% for NP1EO, NP2EO, and NP in Hsin-Hai I. The average removal potential of EDs in freshwater constructed wetlands, in decreasing order, was Hsin-Hai II>Daniaopi>Hsin-Hai I constructed wetlands. The lowest concentrations of the selected compounds were observed in the winter. The highest removal efficiency of the selected phenolic endocrine disruptors was achieved by Hsin-Hai I wetland. The calculated risk quotients used to evaluate the ecological risk were up to 30 times higher in the freshwater wetlands along Dahan River than in the estuarine (DBNSA) constructed wetlands, indicating

  10. Do tropical wetland plants possess convective gas flow mechanisms?

    PubMed

    Konnerup, Dennis; Sorrell, Brian K; Brix, Hans

    2011-04-01

    • Internal pressurization and convective gas flow, which can aerate wetland plants more efficiently than diffusion, are common in temperate species. Here, we present the first survey of convective flow in a range of tropical plants. • The occurrence of pressurization and convective flow was determined in 20 common wetland plants from the Mekong Delta in Vietnam. The diel variation in pressurization in culms and the convective flow and gas composition from stubbles were examined for Eleocharis dulcis, Phragmites vallatoria and Hymenachne acutigluma, and related to light, humidity and air temperature. • Nine of the 20 species studied were able to build up a static pressure of > 50 Pa, and eight species had convective flow rates higher than 1 ml min(-1). There was a clear diel variation, with higher pressures and flows during the day than during the night, when pressures and flows were close to zero. • It is concluded that convective flow through shoots and rhizomes is a common mechanism for below-ground aeration of tropical wetland plants and that plants with convective flow might have a competitive advantage for growth in deep water.

  11. Do tropical wetland plants possess convective gas flow mechanisms?

    PubMed

    Konnerup, Dennis; Sorrell, Brian K; Brix, Hans

    2011-04-01

    • Internal pressurization and convective gas flow, which can aerate wetland plants more efficiently than diffusion, are common in temperate species. Here, we present the first survey of convective flow in a range of tropical plants. • The occurrence of pressurization and convective flow was determined in 20 common wetland plants from the Mekong Delta in Vietnam. The diel variation in pressurization in culms and the convective flow and gas composition from stubbles were examined for Eleocharis dulcis, Phragmites vallatoria and Hymenachne acutigluma, and related to light, humidity and air temperature. • Nine of the 20 species studied were able to build up a static pressure of > 50 Pa, and eight species had convective flow rates higher than 1 ml min(-1). There was a clear diel variation, with higher pressures and flows during the day than during the night, when pressures and flows were close to zero. • It is concluded that convective flow through shoots and rhizomes is a common mechanism for below-ground aeration of tropical wetland plants and that plants with convective flow might have a competitive advantage for growth in deep water. PMID:21175639

  12. Effect of a constructed wetland on disinfection byproducts: Removal processes and production of precursors

    USGS Publications Warehouse

    Rostad, C.E.; Martin, B.S.; Barber, L.B.; Leenheer, J.A.; Daniel, S.R.

    2000-01-01

    The fate of halogenated disinfection byproducts (DBPs) in treatment wetlands and the changes in the DBP formation potential as wastewater treatment plant (WWTP)-derived water moves through the wetlands were investigated. Wetland inlet and outlet samples were analyzed for total organic halide (TOX), trihalomethanes (TH M), haloacetic acids (HAA), dissolved organic carbon (DOC), and UV absorbance. Removal of DBPs by the wetland ranged from 13 to 55% for TOX, from 78 to 97% for THM, and from 67 to 96% for HAA. The 24-h and 7-day nonpurgeable total organic halide (NPTOX), THM, and HAA formation potential yields were determined at the inlet and outlet of these wetlands. The effect of wetlands on the production of DBP precursors and their DBP-formation potential yield from wastewater was dramatic. The wetlands increased DBP yield up to a factor of almost 30. Specific changes in the DOC precursors were identified using 13C NMR spectroscopy.The fate of halogenated disinfection byproducts (DBPs) in treatment wetlands and the changes in the DBP formation potential as wastewater treatment plant (WWTP)-derived water moves through the wetlands were investigated. Wetland inlet and outlet samples were analyzed for total organic halide (TOX), trihalomethanes (THM), haloacetic acids (HAA), dissolved organic carbon (DOC), and UV absorbance. Removal of DBPs by the wetland ranged from 13 to 55% for TOX, from 78 to 97% for THM, and from 67 to 96% for HAA. The 24-h and 7-day nonpurgeable total organic halide (NPTOX), THM, and HAA formation potential yields were determined at the inlet and outlet of these wetlands. The effect of wetlands on the production of DBP precursors and their DBP-formation potential yield from wastewater was dramatic. The wetlands increased DBP yield up to a factor of almost 30. Specific changes in the DOC precursors were identified using 13C NMR spectroscopy.

  13. Ibuprofen removal in horizontal subsurface flow constructed wetlands: treatment performance and fungal community dynamics.

    PubMed

    Zhang, Dongqing; Luo, Jinxue; Lee, Zarraz May Ping; Gersberg, Richard M; Liu, Yu; Tan, Soon Keat; Ng, Wun Jern

    2016-01-01

    The treatment performance of ibuprofen (IBP)-enriched wastewater by horizontal subsurface flow constructed wetlands planted with cattail (Typha angustifolia) and unplanted control mesocosms was investigated. Removal efficiencies of IBP were significantly (p < .05) enhanced in the planted mesocosms (78.5%) compared to those in the unplanted beds (57.9%). An 18S rRNA gene high-throughput pyrosequencing approach was used to investigate the effects of IBP on the structure of the fungal community in these wetland systems. The overall diversity of the fungal community was reduced under the IBP exposure. Taxonomic analysis revealed that 62.2% of the fungal sequences were affiliated with Basidiomycota, followed by Ascomycota (37.4%) at the phylum level. Uncultured fungus (48.2%), Chaetomium sp. (14.2%), Aspergillus sp. (12.4%), Trichoderma sp. (5.7%), Cladosporium sp. (5.4%), and Emericellopsis sp. (5.2%) were identified as dominant genera. At the genus level, a distinct profile of the fungal community in the IBP-enriched mesocosms was observed as compared to the control beds, and as well specific fungal genera were enhanced in the planted beds, regardless of IBP enrichment. However, despite these differences, the composition of the fungal community (as measured by Bray-Curtis similarity) was mostly unaffected by the significant IBP enrichment. On the other hand, a consistent similarity pattern of fungal community structure in the planted mesocosms suggests that the presence of higher macrophytes in the wetland systems may well help shape the fungal community structure.

  14. Microbial density and diversity in constructed wetland systems and the relation to pollutant removal efficiency.

    PubMed

    Zhang, Yang; Carvalho, Pedro N; Lv, Tao; Arias, Carlos; Brix, Hans; Chen, Zhanghe

    2016-01-01

    Microbes are believed to be at the core of the wastewater treatment processes in constructed wetlands (CWs). The aim of this study was to assess the microbial biomass carbon (MBC) and Shannon's diversity index (SDI) in the substrate of CWs planted with Phragmites australis, Hymenocallis littoralis, Canna indica and Cyperus flabelliformis, and to relate MBC and SDI to the pollutant removal in the systems. Significant higher MBC was observed in CWs with H. littoralis and C. indica than in CWs with P. australis, and the MBC differed with season and substrate depth. The microbial community in the wetlands included four phyla: Cyanobacteria, Proteobacteria, Chloroflexi, and Acidobacteria, with a more diverse community structure in wetlands with C. flabelliformis. The MBC in the substrate and the SDI of the 15-20 cm depth correlated with the removal of biochemical oxygen demand, NH4-N and NO3-N. Our results indicate that substrate SDI and MBC can both be regarded as bioindicators of the pollutant removal ability in CWs. PMID:26877053

  15. Wastewater treatment performance efficiency of constructed wetlands in African countries: a review.

    PubMed

    Mekonnen, Andualem; Leta, Seyoum; Njau, Karoli Nicholas

    2015-01-01

    In Africa, different studies have been conducted at different scales to evaluate wastewater treatment efficiency of constructed wetland. This paper aims to review the treatment performance efficiency of constructed wetland used in African countries. In the reviewed papers, the operational parameters, size and type of wetland used and the treatment efficiency are assessed. The results are organized and presented in six tables based on the type of wetland and wastewater used in the study. The results of the review papers indicated that most of the studies were conducted in Tanzania, Egypt and Kenya. In Kenya and Tanzania, different full-scale wetlands are widely used in treating wastewater. Among wetland type, horizontal subsurface flow wetlands were widely studied followed by surface flow and hybrid wetlands. Most of the reported hybrid wetlands were in Kenya. The results of the review papers indicated that wetlands are efficient in removing organic matter (biochemical oxygen demand and chemical oxygen demand) and suspended solids. On the other hand, nutrient removal efficiency appeared to be low.

  16. Removal of the pesticides imazalil and tebuconazole in saturated constructed wetland mesocosms.

    PubMed

    Lv, Tao; Zhang, Yang; Zhang, Liang; Carvalho, Pedro N; Arias, Carlos A; Brix, Hans

    2016-03-15

    The aim of this study was to investigate the removal of the pesticides imazalil and tebuconazole at realistic concentration levels (10 and 100 μg L(-1)) in saturated constructed wetland (CW) mesocosms planted with five wetland plant species (Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta) at different hydraulic loading rates during summer and winter. The removal of imazalil and tebuconazole was not influenced by the influent concentration, but the removal efficiency for both compounds was lower in winter than in summer. Planted mesocosms had significantly higher removal efficiencies than the unplanted controls only in summer. The first-order kinetics model fitted the tebuconazole removal in all mesocosms, and the reaction rate constants varied by plant species and season (0.1-0.7 d(-1) in winter and 0.6-2.9 d(-1) in summer). For imazalil, the first-order kinetics model fitted the removal only in mesocosms planted with Phragmites australis (k = 1.2 ± 0.4 d(-1)) and in the unplanted control (k = 1.2 ± 0.5 d(-1) in both summer and winter). The removal of imazalil and tebuconazole by sorption to the bed substrate and plant uptake were low, suggesting a high rate of metabolization in the saturated CW mesocosms. The removal of imazalil and tebuconazole correlated with the rate of evapotranspiration and the removal of nutrients (N and P) during summer and with the DO/oxygen saturation during winter. This reveals two possible metabolization pathways: degradation inside the plant tissue after uptake and plant-stimulated microbial degradation in the bed substrate. Furthermore, the results indicate that nitrifying bacteria may play an active role in the biodegradation of these pesticides.

  17. Removal of the pesticides imazalil and tebuconazole in saturated constructed wetland mesocosms.

    PubMed

    Lv, Tao; Zhang, Yang; Zhang, Liang; Carvalho, Pedro N; Arias, Carlos A; Brix, Hans

    2016-03-15

    The aim of this study was to investigate the removal of the pesticides imazalil and tebuconazole at realistic concentration levels (10 and 100 μg L(-1)) in saturated constructed wetland (CW) mesocosms planted with five wetland plant species (Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta) at different hydraulic loading rates during summer and winter. The removal of imazalil and tebuconazole was not influenced by the influent concentration, but the removal efficiency for both compounds was lower in winter than in summer. Planted mesocosms had significantly higher removal efficiencies than the unplanted controls only in summer. The first-order kinetics model fitted the tebuconazole removal in all mesocosms, and the reaction rate constants varied by plant species and season (0.1-0.7 d(-1) in winter and 0.6-2.9 d(-1) in summer). For imazalil, the first-order kinetics model fitted the removal only in mesocosms planted with Phragmites australis (k = 1.2 ± 0.4 d(-1)) and in the unplanted control (k = 1.2 ± 0.5 d(-1) in both summer and winter). The removal of imazalil and tebuconazole by sorption to the bed substrate and plant uptake were low, suggesting a high rate of metabolization in the saturated CW mesocosms. The removal of imazalil and tebuconazole correlated with the rate of evapotranspiration and the removal of nutrients (N and P) during summer and with the DO/oxygen saturation during winter. This reveals two possible metabolization pathways: degradation inside the plant tissue after uptake and plant-stimulated microbial degradation in the bed substrate. Furthermore, the results indicate that nitrifying bacteria may play an active role in the biodegradation of these pesticides. PMID:26774264

  18. Nutrient removal from piggery effluent using vertical flow constructed wetlands in southern Brazil.

    PubMed

    Sezerino, P H; Reginatto, V; Santos, M A; Kayser, K; Kunst, S; Philippi, L S; Soares, H M

    2003-01-01

    Santa Catarina State, southern Brazil, has the greatest swine breeding activities of Latin America. Generally, the piggery wastewater is treated in pond systems that are able to remove organic material according to local environmental legislation. However, these systems do not remove nitrogen and phosphorus efficiently. This work deals with a post-treatment system, using vertical flow constructed wetlands. The experiment was conducted in a swine production farm which has 45,000 animals. Although the pond system was able to partially remove the content of nutrients, their concentration in the effluent was high for environmental disposal. A four-bed vertical flow constructed wetland pilot plant, using Typha spp., was built. The pilot plant operated for 280 days for beds 2-4 (sand 2). However, the experiments with beds 1-3 (sand 1) were stopped after 111 days of operation, when a reduction in the wastewater drainage was observed. The beds with sand 2 showed a 33% COD removal, and about 49% of nitrification was observed from 111 days until the end of the operation. PO(4)-P removal was 45% with a loading rate of around 1.36 g m(-2) d(-1).

  19. [Limestone and pyrite-limestone constructed wetlands for treating river water].

    PubMed

    Zhang, Jing; Li, Rui-hua; Li, Jie; Hu, Jun-song; Sun, Qian-qian

    2013-09-01

    Polluted river water was treated with limestone and pyrite-limestone subsurface horizontal constructed wetlands. The aims were to know the performance of two wetlands on removal of common pollutants, especially nitrogen and phosphorus, and analyze the actions of these minerals. The relationship between hydraulic retention time and purification performance of two constructed wetlands was studied. The optimal hydraulic retention time for pollutant removal was about 3 d, The average removal efficiency of COD, TN and TP were 51%, 70% and 95%, respectively. With same influent and hydraulic loading, the average removal efficiency of COD, NH4+ -N, TN and TP were 53.93%, 82.13%, 66%, 50.9%, and 51.66%, 77.43%, 72.06%, 97.35% for limestone and pyrite-limestone constructed wetlands, respectively. There were few differences between limestone and pyrite-limestone wetlands on COD removal, but the nitrogen and phosphorus removal of pyrite-limestone constructed wetland was higher than that of limestone constructed wetland. The phosphorus removal of pyrite-limestone wetland was more efficiency and stable, not affected by temperature.

  20. Pipeline corridors through wetlands -- Impacts on plant communities: Norris Brook Crossing Peabody, Massachusetts

    SciTech Connect

    Shem, L.M.; Van Dyke, G.D.; Zimmerman, R.E.

    1994-12-01

    The goal of the Gas Research Institute Wetland Corridors Program is to document impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents the results of a survey conducted August 17--19, 1992, at the Norris Brook crossing in the town of Peabody, Essex County, Massachusetts. The pipeline at this site was installed during September and October 1990. A backhoe was used to install the pipeline. The pipe was assembled on the adjacent upland and slid into the trench, after which the backhoe was used again to fill the trench and cover the pipeline. Within two years after pipeline construction, a dense vegetative community, composed predominantly of native perennial species, had become established on the ROW. Compared with adjacent natural areas undisturbed by pipeline installation, there was an increase in purple loosestrife and cattail within the ROW, while large woody species were excluded from the ROW. As a result of the ROW`s presence, habitat diversity, edge-type habitat, and species diversity increased within the site. Crooked-stem aster, Aster prenanthoides (a species on the Massasschusetts list of plants of special concern), occurred in low numbers in the adjacent natural areas and had reinvaded the ROW in low numbers.

  1. Emerging organic contaminant removal depending on primary treatment and operational strategy in horizontal subsurface flow constructed wetlands: influence of redox.

    PubMed

    Avila, Cristina; Reyes, Carolina; Bayona, Josep María; García, Joan

    2013-01-01

    This study aimed at assessing the influence of primary treatment (hydrolytic upflow sludge blanket (HUSB) reactor vs. conventional settling) and operational strategy (alternation of saturated/unsaturated phases vs. permanently saturated) on the removal of various emerging organic contaminants (i.e. ibuprofen, diclofenac, acetaminophen, tonalide, oxybenzone, bisphenol A) in horizontal subsurface flow constructed wetlands. For that purpose, a continuous injection experiment was carried out in an experimental treatment plant for 26 days. The plant had 3 treatment lines: a control line (settler-wetland permanently saturated), a batch line (settler-wetland operated with saturate/unsaturated phases) and an anaerobic line (HUSB reactor-wetland permanently saturated). In each line, wetlands had a surface area of 2.95 m(2), a water depth of 25 cm and a granular medium D(60) = 7.3 mm, and were planted with common reed. During the study period the wetlands were operated at a hydraulic and organic load of 25 mm/d and about 4.7 g BOD/m(2)d, respectively. The injection experiment delivered very robust results that show how the occurrence of higher redox potentials within the wetland bed promotes the elimination of conventional quality parameters as well as emerging microcontaminants. Overall, removal efficiencies were always greater for the batch line than for the control and anaerobic lines, and to this respect statistically significantly differences were found for ibuprofen, diclofenac, oxybenzone and bisphenol A. As an example, ibuprofen, whose major removal mechanism has been reported to be biodegradation under aerobic conditions, showed a higher removal in the batch line (85%) than in the control (63%) and anaerobic (52%) lines. Bisphenol A showed also a great dependence on the redox status of the wetlands, finding an 89% removal rate for the batch line, as opposed to the control and anaerobic lines (79 and 65%, respectively). Furthermore, diclofenac showed a greater

  2. Phosphorus removal in laboratory-scale unvegetated vertical subsurface flow constructed wetland systems using alum sludge as main substrate.

    PubMed

    Babatunde, A O; Zhao, Y Q

    2009-01-01

    This research has two eventual goals: (1) To optimize performance of subsurface constructed wetlands for removal of phosphorus (P) (2) To demonstrate that dewatered alum sludge (a by-product), can be reused as a constructed wetland substrate. To achieve these, alum sludge from a water treatment plant was characterized and used as main substrate in four experimental vertical sub-surface flow constructed wetland systems treating dairy farm wastewater. Results show that the alum sludge has suitable hydraulic characteristics (uniformity coefficient = 3.6) for use as a substrate, and in the batch studies, up to 48.6 mg-P was removed by 1 g of the alum sludge at a P concentration of 360 mg-P/l and a dosage of 5 g/l. Results from the experimental systems highlight the significant P removal ability of the alum sludge. However, the inclusion of pea gravel at the infiltrative surface of some of the systems had a negative effect on the P removal performance. Sequential P-fractionation results show that there was no significant increase in the easily extractable P, but for total P, there was significant increase, although this was found to decrease with depth. This study shows that the novel use of dewatered alum sludge can bring about high P removal in vertical subsurface flow constructed wetland systems.

  3. Wineries wastewater treatment by constructed wetlands: a review.

    PubMed

    Masi, F; Rochereau, J; Troesch, S; Ruiz, I; Soto, M

    2015-01-01

    The application of wetland systems for the treatment of wineries wastewater started in the early 1990s in the USA followed a few years later by France, Italy, Germany and Spain. Various studies demonstrated the efficiency of constructed wetlands (CWs) as a low cost, low maintenance and energy-saving technology for the treatment of wineries wastewater. Several of these experiences have also shown lessons to be learnt, such as some limits in the tolerance of the horizontal subsurface flow and vertical subsurface flow classic CWs to the strength of the wineries wastewater, especially in the first stage for the multistage systems. This paper is presenting an overview of all the reported experiences at worldwide level during the last 15 years, giving particular attention and provision of details to those systems that have proven to get reliable and constant performances in the long-term period and that have been designed and realized as optimized solutions for the application of CW technology to this particular kind of wastewater. The organic loading rates (OLRs) applied to the examined 13 CW systems ranged from about 30 up to about 5,000 gCOD/m² d (COD: chemical oxygen demand), with the 80th percentile of the reported values being below 297 gCOD/m² d and the median at 164 gCOD/m² d; the highest OLR values have in all cases been measured during the peak season (vintage) and often have been linked to lower surface removal rates (SRRs) in comparison to the other periods of the year. With such OLRs the SRRs have ranged from a minimum of 15 up to 4,700 gCOD/m² d, with the 80th percentile of the reported values being below 308 gCOD/m² d and the median at 112 gCOD/m² d. PMID:25909720

  4. Using stable isotopes of water and strontium to investigate the hydrology of a natural and a constructed wetland

    USGS Publications Warehouse

    Hunt, R.J.; Bullen, T.D.; Krabbenhoft, D.P.; Kendall, C.

    1998-01-01

    Wetlands cannot exist without water, but wetland hydrology is difficult to characterize. As a result, compensatory wetland mitigation often only assumes the proper hydrology has been created. In this study, water sources and mass transfer processes in a natural and constructed wetland complex were investigated using isotopes of water and strontium. Water isotope profiles in the saturated zone revealed that the natural wetland and one site in the constructed wetland were primarily fed by ground water; profiles in another constructed wetland site showed recent rain was the predominant source of water in the root zone. Water isotopes in the capillary fringe indicated that the residence time for rain is less in the natural wetland than in the constructed wetland, thus transpiration (an important water sink) was greater in the natural wetland. Strontium isotopes showed a systematic difference between the natural and constructed wetlands that we attribute to the presence or absence of peat. In the peat-rich natural wetland, ??87Sr in the pore water increased along the flowline due to preferential weathering of minerals containing radiogenic Sr in response to elevated Fe concentrations in the water. In the constructed wetland, where peat thickness was thin and Fe concentrations in water were negligible, ??87Sr did not increase along the flowline. The source of the peat (on-site or off-site derived) applied in the constructed wetland controlled the ??87Sr at the top of the profile, but the effects were restricted by strong cation exchange in the underlying fluvial sediments. Based on the results of this study, neither constructed wetland site duplicated the water source and weathering environment of the adjoining natural wetland. Moreover, stable isotopes were shown to be effective tools for investigating wetlands and gaining insight not easily obtained using non-isotopic techniques. These tools have potential widespread application to wetlands that have distinct isotopic

  5. Constructed wetlands for sewage effluent treatment and mosquito larvae at two sites in subtropical Australia.

    PubMed

    Dale, Pat E R; Greenway, Margaret; Chapman, Heather; Breitfuss, Mark J

    2007-06-01

    This study of 2 wetlands in subtropical Australia, constructed to treat sewage effluent, examined the relationships between dips positive for mosquito larvae and water quality, operational status of the system, vegetation, and nontarget macroinvertebrates. One site is inland and the other is close to the coast. Larvae of disease vector mosquitoes were present at various times in the wetlands, especially in summer and autumn. The proportion of early instars (1st and 2nd) was greater than that of later ones (3rd and 4th). Dissolved oxygen was negatively, and temperature was positively, associated with the proportion of dips containing larvae. For the coastal site we noted that larvae were more common during draw-down of water for maintenance and also as the system started to come online. Vegetation associated with larvae included dense Typha orientalis and algae. Where there were several types of plants, such as at the coastal site, plant density and water depth were not significantly related to larval presence. Where there were several types of macroinvertebrates there were fewer dips positive for larvae. To provide water treatment capacity and minimal mosquito production we concluded that design should include a variety of plant types, discouraging low dissolved oxygen (for example, by aeration) and ongoing maintenance should be carried out in winter or spring, when mosquitoes are fewer than in summer.

  6. Observations of nitrogen and phosphorus biogeochemistry in a surface flow constructed wetland.

    PubMed

    Erler, Dirk V; Tait, Douglas; Eyre, Bradley D; Bingham, Michael

    2011-11-15

    Free surface water constructed wetlands (CWs) provide a buffer between domestic wastewater treatment plants and natural waterways. Understanding the biogeochemical processes in CWs is crucial to improve their performance. In this study we measured a range of water and sediment parameters, and biogeochemical processes, in an effort to describe the processing of nutrients within two wetland cells in series. As a whole the studied CW effectively absorbed both nitrogen (N) and phosphorus (P) emanating from the waste treatment plant. However the two individual cells showed marked differences related to the availability of oxygen within the water column and the sediments. In one cell we speculated that the prevalence of surface plant species reduced its ability to function as a net nutrient sink. Here we observed a build-up of sediment organic matter, sediment anoxia, a decoupling of nitrification-denitrification, and a flux of N and P out of the sediments to the overlying water. The availability of DO in the surface sediments of the second studied cell led to improved coupling between nitrification-denitrification and a net uptake of both NH4+ and PO4(3-). We hypothesise that the dominance of deeply rooted macrophytes in the second cell was responsible for the improved sediment quality.

  7. [Evolution of Dissolved Organic Matter Properties in a Constructed Wetland of Xiao River, Hebei].

    PubMed

    Ma, Li-na; Zhang, Hui; Tan, Wen-bing; Yu, Min-da; Huang, Zhi-gang; Gao, Ru-tai; Xi, Bei-dou; He, Xiao-song

    2016-01-01

    The evolution of water DOC and COD, and the source, chemical structure, humification degree and redox of dissolved organic matter (DOM) in a constructed wetland of Xiao River, Hebei, was investigated by 3D excitation--emission matrix fluorescence spectroscopy coupled with ultraviolet spectroscopy and chemical reduction, in order to explore the geochemical processes and environmental effects of DOM. Although DOC contributes at least 60% to COD, its decrease in the constructed wetland is mainly caused by the more extensive degradation of elements N, H, S, and P than C in DOM, and 65% is contributed from the former. DOM is mainly consisted of microbial products based on proxies f470/520 and BIX, indicating that DOM in water is apparently affected by microbial degradation. The result based on PARAFAC model shows that DOM in the constructed wetland contains protein-like and humus-like components, and Fulvic- and humic-like components are relatively easier to degrade than protein-like components. Fulvic- and humic-like components undergo similar decomposition in the constructed wetland. A common source of chromophoric dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM) exists; both CDOM and FDOM are mainly composed of a humus-like material and do not exhibit selective degradation in the constructed wetland. The proxies E2 /E3, A240-400, r(A, C) and HIX in water have no changes after flowing into the constructed wetland, implying that the humification degree of DOM in water is hardly affected by wet constructed wetland. However, the constructed wetland environment is not only beneficial in forming the reduced state of DOM, but also facilitates the reduction of ferric. It can also improve the capability of DOM to function as an electron shuttle. This result may be related to the condition that the aromatic carbon of DOM can be stabilized well in the constructed wetland.

  8. Nitrogen transformation in horizontal subsurface flow constructed wetlands II: Effect of biofilm

    NASA Astrophysics Data System (ADS)

    Bigambo, T.; Mayo, A. W.

    In this paper the significance of the biofilm biomass present in horizontal subsurface flow constructed wetland in removal of nitrogen was demonstrated. The model was developed and optimised using data obtained in a horizontal subsurface flow constructed wetland planted with Phragmites mauritianus and filled with 6-25 mm diameter gravel pack. The effects of biofilm biomass activities were studied by removing the effects of plant and gravel bed biofilm in an already calibrated model and re-run the same. Research results indicate that total nitrogen removal was largely influenced by growth of biofilm on plants than on aggregates. When plant biofilm and suspended biomasses were considered total nitrogen removal of 38.1% was observed compared with 25.1% when aggregate-biofilm and suspended biomasses were considered because plants have more surface areas, which are active sites for the effective biofilm activities than aggregates. However, in a natural wetland where the soil grain size is smaller, the effect of biofilm on plants may be smaller than biofilm on soil particles. There was no significant difference in organic-nitrogen effluent concentrations when biofilm biomass was considered or rejected. The averages in organic-nitrogen effluent concentrations were 0.39, 0.41 and 0.53 gN/m 2 for suspended alone, aggregate-biofilm and suspended; and suspended and plant-biofilm, respectively. This indicates that the removal of organic-nitrogen in wastewater is not significantly influenced by biofilm activities. Sedimentation and mineralization processes are the major factors influencing the concentration of organic-nitrogen in the effluent. On the other hand, biofilm activities had significant influence on ammonia-nitrogen and nitrate-nitrogen transformation. The developed model output indicates that the effluent ammonia concentration was 2 gN/m 2, but in absence of biofilm the effluent ammonia concentration increases to 3.5 gN/m 2. Statistical analysis indicates that the

  9. Performance of a constructed wetland-pond system for treatment and reuse of wastewater from campus buildings.

    PubMed

    Ou, Wen-Sheng; Lin, Ying-Feng; Jing, Shuh-Ren; Lin, Hsien-Te

    2006-11-01

    A constructed wetland-pond system consisting of two free-water-surface-flow (FWS) wetland cells, a scenic pond, and a slag filter in series was used for reclamation of septic tank effluent from a campus building. The results show that FWS wetlands effectively removed major pollutants under a hydraulic loading rate between 2.1 and 4.2 cm/d, with average efficiencies ranging from 74 to 78% for total suspended solids, 73 to 88% for 5-day biochemical oxygen demand, 42 to 49% for total nitrogen, 34 to 70% for total phosphorous, 64 to 79% for total coliforms, and 90 to 99.9% for Escherichia coli. After passing through the scenic pond and slag filter, the reclaimed water was used for landscape irrigation. There were a variety of ornamental plants and aquatic animals established in the second FWS cell and scenic pond with good water quality, thus enhancing landscape and ecology amenity in campuses.

  10. Carbon sequestration in surface flow constructed wetland after 12 years of swine wastewater treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Constructed wetlands used for the treatment of swine wastewater may potentially sequester significant amounts of carbon. In past studies, we evaluated the treatment efficiency of wastewater in marsh-pond-marsh design wetland system. The functionality of this system was highly dependent on soil carbo...

  11. Constructed wetlands for water pollution management of aquaculture farms conducting earthen pond culture.

    PubMed

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan; Chang, Yih-Feng; Sui, Hsuan-Yu

    2010-08-01

    This study established farm-scale constructed wetlands integrated to shrimp ponds, using existing earthern pond areas, with a wetland-to-pond ratio of only 0.086 for shrimp culture. The constructed wetlands were used as practice for aquaculture water and wastewater treatment, to regulate the water quality of shrimp ponds and manage pollution from pond effluents. The results of water quality monitoring for influent and effluent showed that constructed wetlands significantly reduced total suspended solids (59 to 72%), turbidity (55 to 65%), chlorophyll a (58 to 72%), 5-day biochemical oxygen demand (29 to 40%), and chemical oxygen demand (13 to 24%) from pond water. The wetland treatment sufficiently regulated water quality of the recirculating shrimp pond, which was significantly (p < 0.05) better than that in a control shrimp pond, without the connection of constructed wetlands. Furthermore, the wetland-treated effluent satisfied the national effluent standards for aquaculture farms (R.O.C. Environmental Protection Administration, 2007). Accordingly, wetland treatment applications were proposed to implement the best management practices to reduce pollution from aquaculture farms in Taiwan.

  12. PREDICTING SUSTAINABLE GROUND WATER TO CONSTRUCTED RIPARIAN WETLANDS: SHAKER TRACE, OHIO, USA

    EPA Science Inventory

    Water isotopy is introduced as a best management practice for the prediction of sustained ground water inflows to prospective constructed wetlands. A primer and application of the stable isotopes, 18O and 2H, are discussed for riparian wetland restoration ar...

  13. Studies on sustainability of simulated constructed wetland system for treatment of urban waste: Design and operation.

    PubMed

    Upadhyay, A K; Bankoti, N S; Rai, U N

    2016-03-15

    New system configurations and wide range of treatability make constructed wetland (CW) as an eco-sustainable on-site approach of waste management. Keeping this view into consideration, a novel configured three-stage simulated CW was designed to study its performance efficiency and relative importance of plants and substrate in purification processes. Two species of submerged plant i.e., Potamogeton crispus and Hydrilla verticillata were selected for this study. After 6 months of establishment, operation and maintenance of simulated wetland, enhanced reduction in physicochemical parameters was observed, which was maximum in the planted CW. The percentage removal (%) of the pollutants in three-stage mesocosms was; conductivity (60.42%), TDS (67.27%), TSS (86.10%), BOD (87.81%), NO3-N (81.28%) and PO4-P (83.54%) at 72 h of retention time. Submerged macrophyte used in simulated wetlands showed a significant time dependent accumulation of toxic metals (p ≤ 0.05). P. crispus accumulated the highest Mn (86.36 μg g(-1) dw) in its tissue followed by Cr (54.16 μg g(-1) dw), Pb (31.56 μg g(-1) dw), Zn (28.06 μg g(-1) dw) and Cu (25.76 μg g(-1) dw), respectively. In the case of H. verticillata, it was Zn (45.29), Mn (42.64), Pb (22.62), Cu (18.09) and Cr (16.31 μg g(-1) dw). Thus, results suggest that the application of simulated CW tackles the water pollution problem more efficiently and could be exploited in small community level as alternative and cost effective tools of phytoremediation.

  14. Studies on sustainability of simulated constructed wetland system for treatment of urban waste: Design and operation.

    PubMed

    Upadhyay, A K; Bankoti, N S; Rai, U N

    2016-03-15

    New system configurations and wide range of treatability make constructed wetland (CW) as an eco-sustainable on-site approach of waste management. Keeping this view into consideration, a novel configured three-stage simulated CW was designed to study its performance efficiency and relative importance of plants and substrate in purification processes. Two species of submerged plant i.e., Potamogeton crispus and Hydrilla verticillata were selected for this study. After 6 months of establishment, operation and maintenance of simulated wetland, enhanced reduction in physicochemical parameters was observed, which was maximum in the planted CW. The percentage removal (%) of the pollutants in three-stage mesocosms was; conductivity (60.42%), TDS (67.27%), TSS (86.10%), BOD (87.81%), NO3-N (81.28%) and PO4-P (83.54%) at 72 h of retention time. Submerged macrophyte used in simulated wetlands showed a significant time dependent accumulation of toxic metals (p ≤ 0.05). P. crispus accumulated the highest Mn (86.36 μg g(-1) dw) in its tissue followed by Cr (54.16 μg g(-1) dw), Pb (31.56 μg g(-1) dw), Zn (28.06 μg g(-1) dw) and Cu (25.76 μg g(-1) dw), respectively. In the case of H. verticillata, it was Zn (45.29), Mn (42.64), Pb (22.62), Cu (18.09) and Cr (16.31 μg g(-1) dw). Thus, results suggest that the application of simulated CW tackles the water pollution problem more efficiently and could be exploited in small community level as alternative and cost effective tools of phytoremediation. PMID:26773432

  15. Application of vertical flow constructed wetland in treatment of heavy metals from pulp and paper industry wastewater.

    PubMed

    Arivoli, A; Mohanraj, R; Seenivasan, R

    2015-09-01

    The paper production is material intensive and generates enormous quantity of wastewater containing organic pollutants and heavy metals. Present study demonstrates the feasibility of constructed wetlands (CWs) to treat the heavy metals from pulp and paper industry effluent by using vertical flow constructed wetlands planted with commonly available macrophytes such as Typha angustifolia, Erianthus arundinaceus, and Phragmites australis. Results indicate that the removal efficiencies of the planted CWs for iron, copper, manganese, zinc, nickel, and cadmium were 74, 80, 60, 70, 71, and 70 %, respectively. On the other hand, the removal efficiency of the unplanted system was significantly lower ranging between 31 and 55 %. Among the macrophytes, T. angustifolia and E. arundinaceus exhibited comparatively higher bioconcentration factor (10(2) to 10(3)) than P. australis.

  16. Evaluating responses of four wetland plant species to different hydroperiods.

    PubMed

    Slusher, C E; Vepraskas, M J; Broome, S W

    2014-03-01

    Previous work has estimated the hydroperiod requirements (saturation duration and frequency) of wetland plant communities by modeling their hydrologic regimes in natural (never drained) wetlands for a 40-yr period. This study tested the modeled predictions in a controlled greenhouse study using tree species representing three of the plant communities plus an additional species from another community. Bald cypress ( L. Rich.), sweet bay ( L.), pond pine ( Michx.), and swamp chestnut oak ( Nutt.) were grown under three hydroperiods (continuously ponded for 100 d, intermittently ponded for 14 d, and unsaturated) in loamy sand and sapric (organic) materials. Bald cypress (representing a Nonriverine Swamp Forest community) adapted well to 100 d of ponding by producing lateral roots near the soil surface and aerenchyma tissue in roots and stem. Sweet bay (Bay Forest community) also adapted well to 100 d of ponding by producing adventitious roots on the submerged portion of the stem. Pond pine (Pond Pine Woodland) and swamp chestnut oak (Nonriverine Wet Hardwood Forest) were intolerant of 100 d of ponded conditions. Seventy-five percent of the pond pine seedlings and 87% of the swamp chestnut oak seedlings died in the continuously ponded treatment level, whereas 100% of the bald cypress and 88% of the sweet bay seedlings survived. Results from this study suggest that modeled long-term hydroperiods of natural wetland plant communities can be used for restoration of these communities. PMID:25602673

  17. Performance of Seasonally and Continuously Loaded Constructed Wetlands Treating Dairy Farm Wastewater.

    PubMed

    Wood, Jeffrey D; Gordon, Robert J; Madani, Ali; Stratton, Glenn W; Bromley, Heather M

    2015-11-01

    A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications. PMID:26641349

  18. Performance of Seasonally and Continuously Loaded Constructed Wetlands Treating Dairy Farm Wastewater.

    PubMed

    Wood, Jeffrey D; Gordon, Robert J; Madani, Ali; Stratton, Glenn W; Bromley, Heather M

    2015-11-01

    A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications.

  19. Removal of pharmaceuticals in microcosm constructed wetlands using Typha spp. and LECA.

    PubMed

    Dordio, Ana; Carvalho, A J Palace; Teixeira, Dora Martins; Dias, Cristina Barrocas; Pinto, Ana Paula

    2010-02-01

    Microcosm constructed wetlands systems established with a matrix of light expanded clay aggregates (LECA) and planted with Typha spp. were used to evaluate their ability to remove pharmaceuticals ibuprofen, carbamazepine and clofibric acid from wastewaters. Seasonal variability of these systems' performances was also evaluated. Overall, removal efficiencies of 96%, 97% and 75% for ibuprofen, carbamazepine and clofibric acid, respectively, were achieved under summer conditions after a retention time of 7 days. In winter, a maximum loss of 26% in removal efficiency was observed for clofibric acid. Removal kinetics was characterized by a fast initial step (>50% removal within 6h) mainly due to adsorption on LECA but, on a larger timescale, plants also contributed significantly to the system's performance. Despite the fact that further tests using larger-scale systems are required, this study points to the possible application of these low-cost wastewater treatment systems for dealing with pharmaceuticals contaminated wastewater.

  20. Constructed wetlands for municipal solid waste landfill leachate treatment. Final report

    SciTech Connect

    Peverly, J.; Sanford, W.E.; Steenhuis, T.S.

    1993-11-01

    In 1989, the US Geological Survey and Cornell University, in cooperation with the New York State Energy Research and Development Authority and the Tompkins County Solid Waste Department, began a three-year study at a municipal solid-waste landfill near Ithaca, New York, to test the effectiveness of leachate treatment with constructed wetlands and to examine the associated treatment processes. Specific objectives of the study were to examine: treatment efficiency as function of substrate composition and grain size, degree of plant growth, and seasonal changes in evapotranspiration rates and microbial activity; effects of leachate and plant growth on the hydraulic characteristics of the substrate; and chemical, biological, and physical processes by which nutrients, metals, and organic compounds are removed from leachate as it flows through the substrate. A parallel study at a municipal solid-waste landfill near Fenton, New York was conducted by researchers at Cornell University, Ithaca College, and Hawk Engineering (Trautmann and others, 1989). Results are described.

  1. Pipeline corridors through wetlands - impacts on plant communities: Cassadaga Creek Tributary Crossing, Gerry Township, Chautauqua County, New York. Topical report, August 1992--November 1993

    SciTech Connect

    Shem, L.M.; Van Dyke, G.D.; Zimmerman, R.E.

    1994-12-01

    The goal of the Gas Research Institute Wetland Corridors Program is to document impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents the results of a survey conducted over the period of August 3-4, 1992, at the Cassadaga wetlands crossing in Gerry Township, Chautauqua County, New York. The pipeline at this site was installed during February and March 1981. After completion of pipeline installation, the ROW was fertilized, mulched, and seeded with annual ryegrass. Two adjacent sites were surveyed in this study: a forested wetland and an emergent wetlands Eleven years after pipeline installation, the ROW at both sites supported diverse vegetative communities. Although devoid of large woody species, the ROW within the forested wetland had a dense vegetative cover. The ROW within the emergent wetland had a slightly less dense and more diverse vegetative community compared with that in the adjacent natural areas (NAs). The ROW within the emergent wetland also had a large number of introduced species that were not present in the adjacent NAs. The ROW, with its emergent marsh plant community, provided habitat diversity within the forested wetlands Because the ROW contained species not found within the adjacent NAs, overall species diversity was increased.

  2. Power Plant Construction

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Stone & Webster Engineering Corporation utilized TAP-A, a COSMIC program originally developed as part of a NASA investigation into the potential of nuclear power for space launch vehicles. It is useful in nuclear power plant design to qualify safety-related equipment at the temperatures it would experience should an accident occur. The program is easy to use, produces accurate results, and is inexpensive to run.

  3. Using stable isotopes of water and strontium to investigate the hydrology of a natural and a constructed wetland

    SciTech Connect

    Hunt, R.J.; Krabbenhoft, D.P.; Bullen, T.D.; Kendall, C.

    1998-05-01

    Wetlands cannot exist without water, but wetland hydrology is difficult to characterize. In this study, water sources and mass transfer processes in a natural and constructed wetland complex were investigated using isotopes of water and strontium. Water isotope profiles in the saturated zone revealed that the natural wetland and one site in the constructed wetland were primarily fed by ground water; profiles in another constructed wetland site showed recent rain was the predominant source of water in the root zone. Water isotopes in the capillary fringe indicated that the residence time for rain is less in the natural wetland than in the constructed wetland, thus transpiration (an important water sink) was greater in the natural wetland. Strontium isotopes showed a systematic difference between the natural and constructed wetlands that the authors attribute to the presence or absence of peat. In the peat-rich natural wetland, {delta}{sup 87}Sr in the pore water increased along the flowline due to preferential weathering of minerals containing radiogenic Sr in response to elevated Fe concentrations in the water. In the constructed wetland, where peak thickness was thin and Fe concentrations in water were negligible, {delta}{sup 87}Sr did not increase along the flowline. The source of the pea (on-site or off-site derived) applied in the constructed wetland controlled the {delta}{sup 87}Sr at the top of the profile, but the effects were restricted by strong cation exchange in the underlying fluvial sediments. Based on the results of this study, neither constructed wetland site duplicated the water source and weathering environment of the adjoining natural wetland. Moreover, stable isotopes were shown to be effective tools for investigating wetlands and gaining insight not easily obtained using non-isotopic techniques. These tools have potential widespread application to wetlands that have distinct isotopic endmember sources.

  4. Preliminary evaluation of a constructed wetland for treating extremely alkaline (pH 12) steel slag drainage.

    PubMed

    Mayes, W M; Aumônier, J; Jarvis, A P

    2009-01-01

    High pH (> 12) leachates are an environmental problem associated with drainage from lime (CaO)-rich industrial residues such as steel slags, lime spoil and coal combustion residues. Recent research has highlighted the potential for natural ('volunteer') wetlands to buffer extremely alkaline influent waters. This appears ascribable to high CO(2) partial pressures in the wetland waters from microbial respiration, which accelerates precipitation of calcium carbonate (CaCO(3)), and the high specific surface area for mineral precipitation offered by macrophytes. The research presented here builds on this and provides preliminary evaluation of a constructed wetland built in March 2008 to buffer drainage from steel slag heaps in north-east England. The drainage water from the slag mounds is characterised by a mean pH of 11.9, high concentrations of Ca (up to 700 mg/L), total alkalinity (up to 800 mg/L as CaCO(3)) and are slightly brackish (Na = 300 mg/L; Cl = 400 mg/L) reflecting native groundwaters at this coastal setting. Documented calcite precipitation rates (mean of 5 g CaCO(3)/m(2)/day) from nearby volunteer sites receiving steel slag drainage were used to scale the constructed wetland planted with Phragmites australis; a species found to spontaneously grow in the vicinity of the discharge. Improved performance of the wetland during summer months may at least in part be due to biological activity which enhances rates of calcite precipitation and thus lowering of pH. Secondary Ca-rich precipitates also serve as a sink for some trace elements present at low concentrations in the slag leachate such as Ni and V. The implications for scaling and applying constructed wetlands for highly alkaline drainage are discussed.

  5. Field test results for nitrogen removal by the constructed wetland component of an agricultural water recycling system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wetland Reservoir Subirrigation Systems (WRSIS) are innovative agricultural water recycling systems that can provide economic and environmental benefits. A constructed wetland is a main component of WRSIS, and an important function of this constructed wetland is drainage water treatment of nitrog...

  6. Performance of dryland and wetland plant species on extensive green roofs

    PubMed Central

    MacIvor, J. Scott; Ranalli, Melissa A.; Lundholm, Jeremy T.

    2011-01-01

    Background and Aims Green roofs are constructed ecosystems where plants perform valuable services, ameliorating the urban environment through roof temperature reductions and stormwater interception. Plant species differ in functional characteristics that alter ecosystem properties. Plant performance research on extensive green roofs has so far indicated that species adapted to dry conditions perform optimally. However, in moist, humid climates, species typical of wetter soils might have advantages over dryland species. In this study, survival, growth and the performance of thermal and stormwater capture functions of three pairs of dryland and wetland plant species were quantified using an extensive modular green roof system. Methods Seedlings of all six species were germinated in a greenhouse and planted into green roof modules with 6 cm of growing medium. There were 34 treatments consisting of each species in monoculture and all combinations of wet- and dryland species in a randomized block design. Performance measures were survival, vegetation cover and roof surface temperature recorded for each module over two growing seasons, water loss (an estimate of evapotranspiration) in 2007, and albedo and water capture in 2008. Key Results Over two seasons, dryland plants performed better than wetland plants, and increasing the number of dryland species in mixtures tended to improve functioning, although there was no clear effect of species or habitat group diversity. All species had survival rates >75 % after the first winter; however, dryland species had much greater cover, an important indicator of green roof performance. Sibbaldiopsis tridentata was the top performing species in monoculture, and was included in the best treatments. Conclusions Although dryland species outperformed wetland species, planting extensive green roofs with both groups decreased performance only slightly, while increasing diversity and possibly habitat value. This study provides further

  7. Susceptibility of riparian wetland plants to perfluorooctanoic acid (PFOA) accumulation.

    PubMed

    Mudumbi, J B N; Ntwampe, S K O; Muganza, M; Okonkwo, J O

    2014-01-01

    As plants have been shown to accumulate organic compounds from contaminated sediments, there is a potential for long-lasting ecological impact as a result of contaminant accumulation in riparian areas of wetlands, particularly the accumulation of non-biodegradable contaminants such as perfluorooctanoic acid (PFOA). In this study, commonly found riparian wetland plants including reeds, i.e., Xanthium strumarium, Phragmites australis, Schoenoplectus corymbosus, Ruppia maritime; Populus canescens, Polygonum salicifolium, Cyperus congestus; Persicaria amphibian, Ficus carica, Artemisia schmidtiana, Eichhornia crassipes, were studied to determine their susceptibility to PFOA accumulation from PFOA contaminated riparian sediment with a known PFOA concentration, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The bioconcentration factor (BCF) indicated that the plants affinity to PFOA accumulation was; E. crassipes, > P. sali-cifolium, > C. congestus, > P. x canescens, > P. amphibian, > F. carica, > A. schmidtiana, > X. strumarium,> P. australis, > R. maritime, > S. corymbosus. The concentration of PFOA in the plants and/or reeds was in the range 11.7 to 38 ng/g, with a BCF range of 0.05 to 0.37. The highest BCF was observed in sediment for which its core water had a high salinity, total organic carbon and a pH which was near neutral. As the studied plants had a higher affinity for PFOA, the resultant effect is that riparian plants such as E. crassipes, X. strumarium, and P. salicifolium, typified by a fibrous rooting system, which grow closer to the water edge, exacerbate the accumulation of PFOA in riparian wetlands.

  8. Susceptibility of riparian wetland plants to perfluorooctanoic acid (PFOA) accumulation.

    PubMed

    Mudumbi, J B N; Ntwampe, S K O; Muganza, M; Okonkwo, J O

    2014-01-01

    As plants have been shown to accumulate organic compounds from contaminated sediments, there is a potential for long-lasting ecological impact as a result of contaminant accumulation in riparian areas of wetlands, particularly the accumulation of non-biodegradable contaminants such as perfluorooctanoic acid (PFOA). In this study, commonly found riparian wetland plants including reeds, i.e., Xanthium strumarium, Phragmites australis, Schoenoplectus corymbosus, Ruppia maritime; Populus canescens, Polygonum salicifolium, Cyperus congestus; Persicaria amphibian, Ficus carica, Artemisia schmidtiana, Eichhornia crassipes, were studied to determine their susceptibility to PFOA accumulation from PFOA contaminated riparian sediment with a known PFOA concentration, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The bioconcentration factor (BCF) indicated that the plants affinity to PFOA accumulation was; E. crassipes, > P. sali-cifolium, > C. congestus, > P. x canescens, > P. amphibian, > F. carica, > A. schmidtiana, > X. strumarium,> P. australis, > R. maritime, > S. corymbosus. The concentration of PFOA in the plants and/or reeds was in the range 11.7 to 38 ng/g, with a BCF range of 0.05 to 0.37. The highest BCF was observed in sediment for which its core water had a high salinity, total organic carbon and a pH which was near neutral. As the studied plants had a higher affinity for PFOA, the resultant effect is that riparian plants such as E. crassipes, X. strumarium, and P. salicifolium, typified by a fibrous rooting system, which grow closer to the water edge, exacerbate the accumulation of PFOA in riparian wetlands. PMID:24933893

  9. Propagation of Human Enteropathogens in Constructed Horizontal Wetlands Used for Tertiary Wastewater Treatment ▿

    PubMed Central

    Graczyk, Thaddeus K.; Lucy, Frances E.; Tamang, Leena; Mashinski, Yessika; Broaders, Michael A.; Connolly, Michelle; Cheng, Hui-Wen A.

    2009-01-01

    Constructed subsurface flow (SSF) and free-surface flow (FSF) wetlands are being increasingly implemented worldwide into wastewater treatments in response to the growing need for microbiologically safe reclaimed waters, which is driven by an exponential increase in the human population and limited water resources. Wastewater samples from four SSF and FSF wetlands in northwestern Ireland were tested qualitatively and quantitatively for Cryptosporidium spp., Giardia duodenalis, and human-pathogenic microsporidia, with assessment of their viability. Overall, seven species of human enteropathogens were detected in wetland influents, vegetated areas, and effluents: Cryptosporidium parvum, C. hominis, C. meleagridis, C. muris, G. duodenalis, Encephalitozoon hellem, and Enterocytozoon bieneusi. SSF wetland had the highest pathogen removal rate (i.e., Cryptosporidium, 97.4%; G. duodenalis, 95.4%); however, most of these values for FSF were in the negative area (mean, −84.0%), meaning that more pathogens were discharged by FSF wetlands than were delivered to wetlands with incoming wastewater. We demonstrate here that (i) the composition of human enteropathogens in wastewater entering and leaving SSF and FSF wetlands is highly complex and dynamic, (ii) the removal and inactivation of human-pathogenic microorganisms were significantly higher at the SSF wetland, (iii) FSF wetlands may not always provide sufficient remediation for human enteropathogens, (iv) wildlife can contribute a substantial load of human zoonotic pathogens to wetlands, (v) most of the pathogens discharged by wetlands were viable, (vi) large volumes of wetland effluents can contribute to contamination of surface waters used for recreation and drinking water abstraction and therefore represent a serious public health threat, and (vii) even with the best pathogen removal rates achieved by SSF wetland, the reduction of pathogens was not enough for a safety reuse of the reclaimed water. To our knowledge, this

  10. BPA and NP removal from municipal wastewater by tropical horizontal subsurface constructed wetlands.

    PubMed

    Toro-Vélez, A F; Madera-Parra, C A; Peña-Varón, M R; Lee, W Y; Bezares-Cruz, J C; Walker, W S; Cárdenas-Henao, H; Quesada-Calderón, S; García-Hernández, H; Lens, P N L

    2016-01-15

    It has been recognized that numerous synthetic compounds like Bisphenol A (BPA) and nonylphenols (NP) are present in effluents from wastewater treatment plants (WWTP) at levels of parts per billion (μg L(-1)) or even parts per trillion (ng L(-1)) with a high potential to cause endocrine disruption in the aquatic environment. Constructed wetlands (CW) are a cost-effective wastewater treatment alternative with promising performance to treat these afore mentioned compounds. This research was aimed to evaluate the efficacy of CW treatment of WWTP effluent for mitigating the effects endocrine disrupting compounds (EDCs). This research goal was accomplished by (1) quantifying the removal of BPA and NP in CWs; (2) isolating CW fungal strains and testing for laccase production; and (3) performing endocrine disruption (reproduction) bioassays using the fruit fly Drosophila melanogaster. Three pilot scale horizontal subsurface flow constructed wetlands (HSSF-CW) were operated for eight weeks: one planted with Phragmites australis; one planted with Heliconia psitacorum; and one unplanted. The Heliconia CW showed a removal efficiency of 73.3(± 19%) and 62.8(± 20.1%) for BPA and NP, respectively; while the Phragmites CW demonstrated a similar removal for BPA (70.2 ± 27%) and lower removal efficiency for NP 52.1(± 37.1%).The unplanted CW achieved 62.2 (± 33%) removal for BPA and 25.3(± 37%) removal for NP. Four of the eleven fungal strains isolated from the Heliconia-CW showed the capacity to produce laccase. Even though complete removal of EDCs was not achieved by the CWs, the bioassay confirmed a significant improvement (p < 0.05) in fly viability for all CWs, with Heliconia sp. being the most effective at mitigating adverse effects on first and second generational reproduction. This study showed that a CW planted with a native Heliconia sp. CW demonstrated a higher removal of endocrine disrupting compounds and better mitigation of reproductive disruption in the

  11. STORMWATER TREATMENT: WET/DRY PONDS VS. CONSTRUCTED WETLANDS

    EPA Science Inventory

    Extant data were used to assess the relative effectiveness of ponds vs. wetland-type BMPs. Compared to wet ponds, wetlands tended toward higher constituent concentrations in effluent, were inefficient at nitrogen removal, and appeared to preferentially retain phosphorous. These d...

  12. Effects of Road De-icing Salts in Constructed Wetlands

    NASA Astrophysics Data System (ADS)

    Silver, P.

    2005-05-01

    In November 2003, a 4-lane highway and 6 mitigation wetlands were opened across the Penn State campus, Erie, Pennsylvania. Road runoff overflows into 1 wetland (T3), and another (R3) receives salt spray and plowed snow. I have logged conductivity and temperature hourly at the sediment-water interface in R3 and T3 since January 2004, and I measure conductivity, temperature, and chironomid density biweekly in all 6 wetlands. Salinity in the wetlands that receive no salt is 0 psu. Biweekly checks of conductivity grossly underestimated winter salinities in T3 and R3. Between January and March 2004, salinity was >5 psu 5 times in R3, and >10 psu 6 times and >30 psu twice in T3. Flushing rates were similar in both wetlands, but time constants were significantly greater in T3 than R3. Salinities returned to 0 psu in both wetlands in May. Chironomid density was significantly lower in T3 than in all other wetlands in summer and autumn, long after salinities at the sediment-water interface returned to 0. Thus, chironomid densities indicated persistent biological effects of de-icers even when measurable salinities were 0 psu. Winter 2005 data show decreasing chironomid density in T3, whereas densities are increasing in the other wetlands.

  13. Variation characteristics of chlorpyrifos in nonsterile wetland plant hydroponic system.

    PubMed

    Wang, Chuan; Zhou, Qiaohong; Zhang, Liping; Zhang, Yan; Xiao, Enrong; Wu, Zhenbin

    2013-01-01

    Six wetland plants were investigated for their effect on the degradation characteristics of chlorpyrifos in nonsterile hydroponic system at constant temperature of 28 degrees C. The results showed that the removal rates of chlorpyrifos in the water of plant systems were 1.26-5.56% higher than that in the control without plants. Scirpus validus and Typha angustifolia were better than other hygrophytes in elimination of chlorpyrifos. The removal rates of the two systems were up to 88%. Plants of acaulescent group had an advantage over caulescent group in removing chlorpyrifos. Phytoaccumulation of chlorpyrifos was observed, and the order of chlorpyrifos concentration in different plant tissues was root > stem > leaf. It was also found that chlorpyrifos and its metabolite TCP decreased rapidly at the initial step of the experiment.

  14. [Treatment effect of constructed wetlands on organic matter in wastewater from pig farm].

    PubMed

    Liao, Xindi; Luo, Shiming

    2002-01-01

    Using plant species Vetiveria zizanioides and Cyperus alternifolius respectively, two constructed wetlands (CWS) with size of 1.0 m x 0.5 m x 0.8 m were established. The purifying function and its change pattern with season, influent concentration and hydraulic retention time (HRT) of the constructed wetlands on the organic matters in wastewater from a pig farm were studied throughout four seasons in the year. The results showed that the two CWS had very stable effects on the removal of COD and BOD, while the organic matters in wastewater changed. The removal rate of COD and BOD was 70% and 80% respectively by HRT 1-2 d in spring. The removal rate of COD reached 90% with the influent of COD 1000-1400 mg.L-1 in summer. The removal rate of COD and BOD was 50-60% and 50% respectively by HRT 1-2 d in autumn. The removal rate of COD reached 70% with the influent of COD 1003 mg.L-1 in winter. There was no significant difference between two CWS in the removal of COD, BOD and SS. The rule of contaminants decreased with the HRT in CWS followed exponential function: Yt = Y0.exp(-kt). The relation between the concentration of contaminants in influent (x) and outflow (y) at the same HRT followed linear relation: y = a + bx.

  15. Comparison of horizontal and vertical constructed wetland systems for landfill leachate treatment.

    PubMed

    Yalcuk, Arda; Ugurlu, Aysenur

    2009-05-01

    The main purpose of this study was to treat organic pollution, ammonia and heavy metals present in landfill leachate by the use of constructed wetland systems and to quantify the effect of feeding mode. The effect of different bedding material (gravel and zeolite surface) was also investigated. A pilot-scale study was conducted on subsurface flow constructed wetland systems operated in vertical and horizontal mode. Two vertical systems differed from each other with their bedding material. The systems were planted with cattail (Typha latifolia) and operated identically at a flow rate of 10 l/day and hydraulic retention times of 11.8 and 12.5 day in vertical 1, vertical 2 and horizontal systems, respectively. Concentration based average removal efficiencies for VF1, VF2 and HF were NH(4)-N, 62.3%, 48.9% and 38.3%; COD, 27.3%, 30.6% and 35.7%; PO(4)-P, 52.6%, 51.9% and 46.7%; Fe(III), 21%, 40% and 17%, respectively. Better NH(4)-N removal performance was observed in the vertical system with zeolite layer than that of the vertical 2 and horizontal system. In contrast, horizontal system was more effective in COD removal.

  16. Key issues to consider when using alum sludge as substrate in constructed wetland.

    PubMed

    Zhao, Xiaohong; Zhao, Yaqian; Wang, Wenke; Yang, Yongzhe; Babatunde, Akintunde; Hu, Yuansheng; Kumar, Lordwin

    2015-01-01

    Globally, alum sludge is an easily, locally and largely available by-product from water treatment plants where aluminium sulphate is used as the coagulant for raw water purification. Owing to the high content of Al ions (29.7±13.3% dry weight) in alum sludge and the strong affinity of Al ions to adsorb various pollutants especially phosphorus (P), alum sludge (in the form of dewatered cakes) has been investigated in recent years as a low-cost alternative substrate in constructed wetland (CW) systems to enhance the treatment efficiency especially for high strength P-containing wastewater. Long-term trials in different scales have demonstrated that the alum sludge-based CW is a promising technique with a two-pronged feature of using 'waste' for wastewater treatment. Alum sludge cakes in CW can serve as a medium for wetland plant growth, as a carrier for biofilm development and as a porous material for wastewater infiltration. After the intensive studies of the alum sludge-based CW system, this paper aims to address the key issues and concerns pertaining to this kind of CW system. These include: (1) Is alum sludge suitable for reuse in CWs? (2) Is Al released from the sludge a concern? (3) What is the lifespan of the alum sludge in CWs? (4) How can P be recovered from the used alum sludge? (5) Does clogging happen in alum sludge-based CW systems and what is the solution? PMID:26067496

  17. Reconstruction of a constructed wetland with horizontal subsurface flow after 18 years of operation.

    PubMed

    Hudcová, Tereza; Vymazal, Jan; Dunajský, Michal Kriška

    2013-01-01

    The constructed wetland (CW) for 326 PE with horizontal subsurface flow at Kotenčice, Central Bohemia, Czech Republic, was built in 1994. Despite the relatively high efficiency of the CW, the filtration beds suffered from clogging, and therefore it was decided in 2011 to rebuild the whole system. The new treatment system was built as an experimental system consisting of four different combinations of horizontal and vertical beds. The major aim of the design was to determine the best hybrid combination which then could be used in the future for refurbishment of older horizontal flow CWs or for the new systems. The mechanical pretreatment consists of mechanical bar screens, a new Imhoff tank, and the original settling tank which has been converted into the accumulation tank from where the wastewater is pumped into the wetlands. The filters are planted with Phragmites australis, Phalaris arundinacea, Iris pseudacorus, Iris sibirica, Glyceria maxima and Lythrum salicaria in order to evaluate and compare various plant species' effect on the treatment process. The new technology includes a tertiary treatment which consists of a greenhouse with a photo-reactor for the cultivation of algae and hydroponic systems (residual nutrients removal), sludge reed-beds and a composting field. PMID:24037174

  18. Key issues to consider when using alum sludge as substrate in constructed wetland.

    PubMed

    Zhao, Xiaohong; Zhao, Yaqian; Wang, Wenke; Yang, Yongzhe; Babatunde, Akintunde; Hu, Yuansheng; Kumar, Lordwin

    2015-01-01

    Globally, alum sludge is an easily, locally and largely available by-product from water treatment plants where aluminium sulphate is used as the coagulant for raw water purification. Owing to the high content of Al ions (29.7±13.3% dry weight) in alum sludge and the strong affinity of Al ions to adsorb various pollutants especially phosphorus (P), alum sludge (in the form of dewatered cakes) has been investigated in recent years as a low-cost alternative substrate in constructed wetland (CW) systems to enhance the treatment efficiency especially for high strength P-containing wastewater. Long-term trials in different scales have demonstrated that the alum sludge-based CW is a promising technique with a two-pronged feature of using 'waste' for wastewater treatment. Alum sludge cakes in CW can serve as a medium for wetland plant growth, as a carrier for biofilm development and as a porous material for wastewater infiltration. After the intensive studies of the alum sludge-based CW system, this paper aims to address the key issues and concerns pertaining to this kind of CW system. These include: (1) Is alum sludge suitable for reuse in CWs? (2) Is Al released from the sludge a concern? (3) What is the lifespan of the alum sludge in CWs? (4) How can P be recovered from the used alum sludge? (5) Does clogging happen in alum sludge-based CW systems and what is the solution?

  19. [Optimization of nitrogen and phosphorus removal in vertical subsurface flow constructed wetlands by using polypropylene pellet as part of substrate].

    PubMed

    Tang, Xian-Qiang; Li, Jin-Zhong; Li, Xue-Ju; Liu, Xue-Gong; Huang, Sui-Liang

    2008-05-01

    Constructed wetlands experiments were conducted by using shale and Typha latifolia L. as vertical subsurface flow constructed wetland substrate and plant for eutrophic Jin River water treatment, and part of shale with polypropylene pellet was replaced to investigate its effect on nitrogen and phosphorus removal. In this study, hydraulic loading rate was equal to 800 mm/d, theoretic residence time was equal to 12 h. During the entire running period, maximal monthly mean ammonia-nitrogen (NH(4+) -N), total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal rates were observed in August 2006. In contrast to the full shale used wetland, polypropylene pellet enhanced ammonia-nitrogen, total nitrogen, soluble reactive phosphorus and total phosphorus removal by 13.38%, 8.9%, 9.29% and 8.25% respectively. After finishing the experiment, aboveground plant biomass (stems and leaves) of Typha latifolia L. was harvested, and its weight and nutrient content (total nitrogen and total phosphorus) were measured. Analysis of aboveground plant biomass indicated that polypropylene pellet restrained the increase in biomass but stimulated assimilation of nitrogen and phosphorus into stems and leaves. The subsequent harvesting of the plants resulted in the additional removal of total nitrogen and phosphorus of about 29.382 g x m(-2) and 13.469 g x m(-2), respectively.

  20. Sequential nitrification/identification in subsurface flow constructed wetlands. A literature review. Master's thesis

    SciTech Connect

    Titus, F.W.

    1992-12-01

    Even though there is currently no consensus on the design of subsurface flow constructed wetlands, the ability of constructed wetlands to meet municipal wastewater requirements is well documented. Nitrogen removal appears from the existing performance data to be one of the primary problems with these systems. The negative effects of excessive levels of nitrogen on the aquatic environment include eutrophication of receiving waters and the increased risk of methemoglobinemia in human infants where elevated levels of nitrate (NO3-) or nitrite (NO2-) nitrogen are present in drinking water supplies. The performance of constructed wetlands for nitrogen removal, at best, can be rated poor to fair. As a result of the negative effects of excessive nitrogen on the environment and the problems with constructed wetlands in consistently removing nitrogen to within acceptable levels, this report will be directed towards the sequential nitrification/denitrification process.

  1. EVALUATION OF CONSTRUCTED WETLAND AND RETENTION POND BMPS FOR ATTENUATING MICROBIAL CONTAMINANTS IN URBAN STORMWATER RUNOFF

    EPA Science Inventory

    This project investigated the use of constructed wetlands and retention ponds for decreasing microbial concentrations from urban stormwater runoff. Increased urbanization has resulted in a larger percentage of impervious areas which cause large quantities of stormwater runoff an...

  2. [Treatment characteristics of saline domestic wastewater by constructed wetland].

    PubMed

    Gao, Feng; Yang, Zhao-Hui; Li, Chen; Jin, Wei-Hong; Deng, Yi-Bing

    2012-11-01

    A series of experiments were conducted to evaluate the feasibility of using constructed wetland (CW) to remove pollutants from saline domestic sewage. The experimental results indicated that the effects of salinity on the contaminant removal were insignificant when the influent salinities of the CWs were less than or equal to 1.5%. For the influent salinity of 0%, 0.5%, 1.0% and 1.5%, the average removal rates of the CWs were found to be above 68.3% for COD and above 66.1% for NH4(+) -N. When the influent salinity was increased to 2.0%, the individual numbers of microorganisms in the CW reduced obviously. It was similar to the change of the soil enzyme activity in the CW. Then the removal efficiency of the CW also dropped significantly. The average removal rate of COD and NH4(+) -N dropped to 52.9% and 50.3%, respectively. The effects of HRT on the treatment performance of CW under the saline condition of 1.5% were also investigated in this study. And the results showed that nitrogen removal was more greatly affected by HRT than organic matter removal. The NH4(+) -N removal efficiency in CW decreased from 65.1% -78.2% to 47.1% when the HRT of the CW varied from 3-5 d to 2 d. PMID:23323411

  3. Ecological effects of roads on the plant diversity of coastal wetland in the Yellow River Delta.

    PubMed

    Li, Yunzhao; Yu, Junbao; Ning, Kai; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

    2014-01-01

    The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of β T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0-20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion.

  4. Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

    2014-01-01

    The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of βT and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing β-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion. PMID:25147872

  5. Diversity, distribution and hydrocarbon biodegradation capabilities of microbial communities in oil-contaminated cyanobacterial mats from a constructed wetland.

    PubMed

    Abed, Raeid M M; Al-Kharusi, Samiha; Prigent, Stephane; Headley, Tom

    2014-01-01

    Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediation of oil-polluted residual waters from an oil field in the desert of the south-eastern Arabian Peninsula, although such mats were rarely found in other wetland systems. There is scarce information on the bacterial diversity, spatial distribution and oil-biodegradation capabilities of freshwater wetland oil-polluted mats. Microbial community analysis by Automated Ribosomal Spacer Analysis (ARISA) showed that the different mats hosted distinct microbial communities. Average numbers of operational taxonomic units (OTUsARISA) were relatively lower in the mats with higher oil levels and the number of shared OTUsARISA between the mats was <60% in most cases. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities in the wetland mats were influenced by oil and ammonia levels, but to a lesser extent by plant density. In addition to oil and ammonia, redundancy analysis (RDA) showed also a significant contribution of temperature, dissolved oxygen and sulfate concentration to the variations of the mats' microbial communities. Pyrosequencing yielded 282,706 reads with >90% of the sequences affiliated to Proteobacteria (41% of total sequences), Cyanobacteria (31%), Bacteriodetes (11.5%), Planctomycetes (7%) and Chloroflexi (3%). Known autotrophic (e.g. Rivularia) and heterotrophic (e.g. Azospira) nitrogen-fixing bacteria as well as purple sulfur and non-sulfur bacteria were frequently encountered in all mats. On the other hand, sequences of known sulfate-reducing bacteria (SRBs) were rarely found, indicating that SRBs in the wetland mats probably belong to yet-undescribed novel species. The wetland mats were able to degrade 53-100% of C12-C30 alkanes after 6 weeks of incubation under aerobic conditions. We conclude that oil and ammonia concentrations are the major key players in determining the spatial distribution of the wetland mats' microbial

  6. Diversity, Distribution and Hydrocarbon Biodegradation Capabilities of Microbial Communities in Oil-Contaminated Cyanobacterial Mats from a Constructed Wetland

    PubMed Central

    Abed, Raeid M. M.; Al-Kharusi, Samiha; Prigent, Stephane; Headley, Tom

    2014-01-01

    Various types of cyanobacterial mats were predominant in a wetland, constructed for the remediation of oil-polluted residual waters from an oil field in the desert of the south-eastern Arabian Peninsula, although such mats were rarely found in other wetland systems. There is scarce information on the bacterial diversity, spatial distribution and oil-biodegradation capabilities of freshwater wetland oil-polluted mats. Microbial community analysis by Automated Ribosomal Spacer Analysis (ARISA) showed that the different mats hosted distinct microbial communities. Average numbers of operational taxonomic units (OTUsARISA) were relatively lower in the mats with higher oil levels and the number of shared OTUsARISA between the mats was <60% in most cases. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities in the wetland mats were influenced by oil and ammonia levels, but to a lesser extent by plant density. In addition to oil and ammonia, redundancy analysis (RDA) showed also a significant contribution of temperature, dissolved oxygen and sulfate concentration to the variations of the mats’ microbial communities. Pyrosequencing yielded 282,706 reads with >90% of the sequences affiliated to Proteobacteria (41% of total sequences), Cyanobacteria (31%), Bacteriodetes (11.5%), Planctomycetes (7%) and Chloroflexi (3%). Known autotrophic (e.g. Rivularia) and heterotrophic (e.g. Azospira) nitrogen-fixing bacteria as well as purple sulfur and non-sulfur bacteria were frequently encountered in all mats. On the other hand, sequences of known sulfate-reducing bacteria (SRBs) were rarely found, indicating that SRBs in the wetland mats probably belong to yet-undescribed novel species. The wetland mats were able to degrade 53–100% of C12–C30 alkanes after 6 weeks of incubation under aerobic conditions. We conclude that oil and ammonia concentrations are the major key players in determining the spatial distribution of the wetland mats

  7. Coastal Freshwater Wetland Plant Community Response to Seasonal Drought and Flooding in Northwestern Costa Rica

    EPA Science Inventory

    In tropical wet-dry climates, seasonal hydrologic cycles drive wetland plant community change and produce distinct seasonal plant assemblages. In this study, we examined the plant community response to seasonal flooding and drought in a large coastal freshwater wetland in northwe...

  8. Evaluation of recharge to the Skunk Creek Aquifer from a constructed wetland near Lyons, South Dakota

    USGS Publications Warehouse

    Thompson, Ryan F.

    2002-01-01

    A wetland was constructed in the Skunk Creek flood plain near Lyons in southeast South Dakota to mitigate for wetland areas that were filled during construction of a municipal golf course for the city of Sioux Falls. A water-rights permit was obtained to allow the city to pump water from Skunk Creek into the wetland during times when the wetland would be dry. The amount of water seeping through the wetland and recharging the underlying Skunk Creek aquifer was not known. The U.S. Geological Survey, in cooperation with the city of Sioux Falls, conducted a study during 1997-2000 to evaluate recharge to the Skunk Creek aquifer from the constructed wetland. Three methods were used to estimate recharge from the wetland to the aquifer: (1) analysis of the rate of water-level decline during periods of no inflow; (2) flow-net analysis; and (3) analysis of the hydrologic budget. The hydrologic budget also was used to evaluate the efficiency of recharge from the wetland to the aquifer. Recharge rates estimated by analysis of shut-off events ranged from 0.21 to 0.82 foot per day, but these estimates may be influenced by possible errors in volume calculations. Recharge rates determined by flow-net analysis were calculated using selected values of hydraulic conductivity and ranged from 566,000 gallons per day using a hydraulic conductivity of 0.5 foot per day to 1,684,000 gallons per day using a hydraulic conductivity of 1.0 foot per day. Recharge rates from the hydrologic budget varied from 0.74 to 0.85 foot per day, and averaged 0.79 foot per day. The amount of water lost to evapotranspiration at the study wetland is very small compared to the amount of water seeping from the wetland into the aquifer. Based on the hydrologic budget, the average recharge efficiency was estimated as 97.9 percent, which indicates that recharging the Skunk Creek aquifer by pumping water into the study wetland is highly efficient. Because the Skunk Creek aquifer is composed of sand and gravel, the

  9. Tolerance to hydraulic and organic load fluctuations in constructed wetlands.

    PubMed

    Masi, F; Martinuzzi, N; Bresciani, R; Giovannelli, L; Conte, G

    2007-01-01

    This paper describes a two-year performance evaluation of four different constructed wetland (CW) treatment systems designed by IRIDRA Srl, located in central Italy. All four CW systems were established to treat wastewater effluent from different tourist activities: (1) one single-stage CW for secondary treatment of domestic wastewater (30 p.e.) at a holiday farm site; (2) a hybrid compact system consisting of two stages, a horizontal flow (HF) system followed by a vertical flow (VF) system for the secondary treatment of effluent from a 140 p.e. tourist resort; (3) a single-stage vertical flow (VF) CW for a 100 p.e. mountain shelter; and (4) a pair of single-stage, HF CWs for the secondary treatment of segregated grey and black water produced by an 80 p.e. camping site. These tourism facilities are located in remote areas and share some common characteristics concerning their water management: they have high variability of water consumption and wastewater flow, depending on the season, weather and weekly regularities; they have no connection to a public sewer and most sites are located in a sensitive environment. Total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonium (N-NH4+), nitrate (N-NOx), total nitrogen (Ntot), total phosphorus (Ptot), total coliform (TC), faecal coliform (FC), E. coli removal efficiencies for all four CW systems are presented. The results from this study demonstrate the potential of CWs as a suitable technology for treating wastewater from tourism facilities in remote areas. A very efficient COD reduction (83-95%) and pathogen elimination (3-5 logs) have been achieved. Furthermore, the CWs are easily maintained, robust (not sensitive to peak flows), constructed with local materials, and operate with relatively low cost.

  10. Construction Simplicity and Cost as Selection Criteria Between Two Types of Constructed Wetlands Treating Highway Runoff

    NASA Astrophysics Data System (ADS)

    Manios, Thrassyvoulos; Fountoulakis, Michalis S.; Karathanasis, Anastasios D.

    2009-05-01

    Two free water surface (FWS) and two subsurface flow (SSF) pilot-size wetlands were constructed for the evaluation of their performance in treating highway runoff (HRO) in the heart of the Mediterranean region, the island of Crete, at the southernmost point of Greece. Detailed recordings of the resources involved during the construction allowed a thorough calculation of the cost of the systems and the requirements in materials, man-hours, and equipment. The two identical FWS systems had a surface area of 33 m2 each, while the two identical SSF covered 32 m2 each. One FWS and one SSF, named FWS12 and SSF12, respectively, were designed with a hydraulic retention time (HRT) of 12 h, with each one capable of treating a maximum HRO of 12.6 m3/day. The other couple, named FWS24 and SSF24, respectively, was designed with an HRT of 24 h, with each receiving a maximum HRO of 6.3 m3/days. An influent storage tank was required to hold the runoff during the common storm events and control the flow rate (and the hydraulic retention time) into the wetlands. This construction represented 25% of the total construction cost, while 5% was spent on the influent automated (and sun-powered) control and distribution system, from the storage tank to the wetlands. The respective total cost allocated to the two SSF systems (€14,676) was approximately 10% higher than that of the FWS (€13,596), mainly due to the three different-sized gravel layers used in the SSF substrate compared to the topsoil used in the FWS, which tripled the cost and placement time. The Total Annual Economic Cost (TAEC) was €1799/year and €1847/year for the FWS and SSF pair, respectively. TAEC was also used to compare the economic efficiency of the systems per cubic meter of HRO treated and kilograms of COD and TSS removed from the wetlands during their first operational year. Based on these estimations, FWS12 recorded the lowest TAECCOD and TAECTSS values (€89.09/kg and €43.69/kg, respectively) compared to

  11. Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading.

    PubMed

    Yu, Guangwei; Tan, Meijuan; Chong, Yunxiao; Long, Xinxian

    2015-01-01

    For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs), two horizontal subsurface flow(HSSF) CWs and two vertical subsurface flow(VSSF) CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P) were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation.

  12. Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading

    PubMed Central

    Yu, Guangwei; Tan, Meijuan; Chong, Yunxiao; Long, Xinxian

    2015-01-01

    For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs), two horizontal subsurface flow(HSSF) CWs and two vertical subsurface flow(VSSF) CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P) were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation. PMID:26218872

  13. A multiple-realizations chance-constrained model for optimizing nutrient removal in constructed wetlands

    NASA Astrophysics Data System (ADS)

    Ng, Tze Ling; Eheart, J. Wayland

    2008-04-01

    High nutrient loads in surface waters are a cause of hypoxia in coastal ecosystems. Constructed wetlands offer a means of nutrient removal, but their design is complicated by environmental fluctuations. In the present work, a chance-constrained model is developed on the basis of satisfying performance constraints for a subset of the period of hydrologic and meteorological record. The model incorporates a nonsteady state wetland model and is used to determine the most cost-efficient wetland design given the nutrient removal requirements. Three candidate wetlands are considered. For two of them a comparison is made between operating the wetlands individually versus operating them concurrently. Results show that the factors limiting wetland performance are low flow availability and low inflow nutrient concentrations. Further, for the case considered, a two-wetland design is found to be more cost-effective than a single-wetland design. On average, wetlands have huge potential for nutrient removal but have a higher risk of failure than conventional treatment and could, under unfavorable conditions, be more expensive.

  14. Nitrogen and COD removal from domestic and synthetic wastewater in subsurface-flow constructed wetlands.

    PubMed

    Collison, R S; Grismer, M E

    2013-09-01

    Comparisons of the performance of constructed-wetland systems (CWs) for treating domestic wastewater in the laboratory and field may use pathogen-free synthetic wastewater to avoid regulatory health concerns. However, little to no data are available describing the relative treatment efficiencies of CWs to both actual and synthetic domestic wastewaters so as to enable such comparison. To fill this gap, treatment performances with respect to organics (chemical organic demand; COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) and a similar-strength synthetic wastewater under planted and non-planted subsurface-flow CWs are determined. One pair of CWs was planted with cattails in May 2008, whereas the adjacent system was non-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each CWs, and effluent samples were collected and tested for COD and nitrogen species regularly during four different periods over six months. Overall, statistically significant greater removal of COD (-12%) and nitrogen (-5%) occurred from the synthetic as compared with the domestic wastewater from the planted and non-planted CWs. Effluent BOD5/COD ratios from the synthetic wastewater CWs averaged nearly twice that from the domestic wastewater CWs (0.17 vs 0.10), reflecting greater concentrations of readily degraded compounds. That removal fractions were consistent across the mid-range loading rates to the CWs suggests that the synthetic wastewater can be used in testing laboratory CWs with reasonable success in application of their results to the field.

  15. Nitrogen and COD removal from domestic and synthetic wastewater in subsurface-flow constructed wetlands.

    PubMed

    Collison, R S; Grismer, M E

    2013-09-01

    Comparisons of the performance of constructed-wetland systems (CWs) for treating domestic wastewater in the laboratory and field may use pathogen-free synthetic wastewater to avoid regulatory health concerns. However, little to no data are available describing the relative treatment efficiencies of CWs to both actual and synthetic domestic wastewaters so as to enable such comparison. To fill this gap, treatment performances with respect to organics (chemical organic demand; COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) and a similar-strength synthetic wastewater under planted and non-planted subsurface-flow CWs are determined. One pair of CWs was planted with cattails in May 2008, whereas the adjacent system was non-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each CWs, and effluent samples were collected and tested for COD and nitrogen species regularly during four different periods over six months. Overall, statistically significant greater removal of COD (-12%) and nitrogen (-5%) occurred from the synthetic as compared with the domestic wastewater from the planted and non-planted CWs. Effluent BOD5/COD ratios from the synthetic wastewater CWs averaged nearly twice that from the domestic wastewater CWs (0.17 vs 0.10), reflecting greater concentrations of readily degraded compounds. That removal fractions were consistent across the mid-range loading rates to the CWs suggests that the synthetic wastewater can be used in testing laboratory CWs with reasonable success in application of their results to the field. PMID:24175415

  16. Treatment of municipal wastewater using horizontal flow constructed wetlands in Egypt.

    PubMed

    Abou-Elela, Sohair I; Golinelli, G; Saad El-Tabl, Abdou; Hellal, Mohammed S

    2014-01-01

    The aim of this study was to evaluate the performance of two pilot horizontal flow constructed wetlands (HFCWs) with and without vegetation. Three types of plants namely Canna, Phragmites australis and Cyprus papyrus were used. The surface area of each plant was 654 m(2). The flow rate was 20 m(3) d(-1) and the organic loading rate range was 1.7-3.4 kg BOD d(-1) with a detention time of 11 days. The results obtained showed that planted HFCW produced high quality effluent in terms of reduction of chemical oxygen demand (COD; 88%), biochemical oxygen demand (BOD; 91%) and total suspended solids (TSS; 92%) as well as nutrient removal. In addition, 4 logs of total coliform were removed from the planted unit compared with only 3 logs in the unplanted one. The phosphate uptake by the plants reached 29, 30.91 and 38.9 g P m(-2) for Canna, Phragmites and Cyprus, respectively, with 60% removal rate in the treated effluent. The nitrogen uptake by the same plants reached 63.1, 49.46 and 82.33 g N m(-2). Although, the unplanted unit proved to be efficient in the removal of COD, BOD and TSS, it lacks efficiency in pathogen and nutrient removal. The reclaimed wastewater, after disinfection, could be reused for non-restricted irrigation purposes. PMID:24434966

  17. French vertical-flow constructed wetland design: adaptations for tropical climates.

    PubMed

    Molle, P; Latune, R Lombard; Riegel, C; Lacombe, G; Esser, D; Mangeot, L

    2015-01-01

    The French Outermost Regions are under tropical climate yet still have to comply with both French and EU regulations. French vertical-flow constructed wetland systems appear well adapted to the technical specifics of these regions but their adaptation to tropical climate requires new design guidelines to be defined (area needed, number of filters, type of plants, material to be used, etc.). A study was started in 2008, with backing from the national water authorities, to implement full-scale experimental sites and assess the impacts of local context on design and performances. This paper reports the monitoring results on three vertical-flow constructed wetlands fed directly with raw wastewater (known as the 'French system') in Mayotte and French Guiana. The plants, now in operation for between 1 and 6 years, range from 160 to 480 population equivalent (p.e.). Monitoring consisted of 28 daily composite flow samples in different seasons (dry season, rainy season) at the inlet and outlet of each filter. Performances are benchmarked against French mainland area standards from Irstea's database. Results show that performances are improved by warmer temperature for chemical oxygen demand (COD), suspended solids (SS) and total Kjeldahl nitrogen (TKN) and satisfy national quality objectives with a single stage of filters. Treatment plant footprint can thus be reduced as only two parallel filters are needed. Indeed, warm temperatures allow faster mineralization of the sludge deposit, making it possible to operate at similar rest and feeding period durations. Systems operated using one twin-filter stage can achieve over 90% COD, SS and TKN removal for a total surface of 0.8 m²/p.e.

  18. French vertical-flow constructed wetland design: adaptations for tropical climates.

    PubMed

    Molle, P; Latune, R Lombard; Riegel, C; Lacombe, G; Esser, D; Mangeot, L

    2015-01-01

    The French Outermost Regions are under tropical climate yet still have to comply with both French and EU regulations. French vertical-flow constructed wetland systems appear well adapted to the technical specifics of these regions but their adaptation to tropical climate requires new design guidelines to be defined (area needed, number of filters, type of plants, material to be used, etc.). A study was started in 2008, with backing from the national water authorities, to implement full-scale experimental sites and assess the impacts of local context on design and performances. This paper reports the monitoring results on three vertical-flow constructed wetlands fed directly with raw wastewater (known as the 'French system') in Mayotte and French Guiana. The plants, now in operation for between 1 and 6 years, range from 160 to 480 population equivalent (p.e.). Monitoring consisted of 28 daily composite flow samples in different seasons (dry season, rainy season) at the inlet and outlet of each filter. Performances are benchmarked against French mainland area standards from Irstea's database. Results show that performances are improved by warmer temperature for chemical oxygen demand (COD), suspended solids (SS) and total Kjeldahl nitrogen (TKN) and satisfy national quality objectives with a single stage of filters. Treatment plant footprint can thus be reduced as only two parallel filters are needed. Indeed, warm temperatures allow faster mineralization of the sludge deposit, making it possible to operate at similar rest and feeding period durations. Systems operated using one twin-filter stage can achieve over 90% COD, SS and TKN removal for a total surface of 0.8 m²/p.e. PMID:26442494

  19. The influence of urbanisation on macroinvertebrate biodiversity in constructed stormwater wetlands.

    PubMed

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M

    2015-12-01

    The construction of wetlands in urban environments is primarily carried out to assist in the removal of contaminants from wastewaters; however, these wetlands have the added benefit of providing habitat for aquatic invertebrates, fish and waterbirds. Stormwater quantity and quality is directly related to impervious area (roads, sealed areas, roofs) in the catchment. As a consequence, it would be expected that impervious area would be related to contaminant load and biodiversity in receiving waters such as urban wetlands. This study aimed to establish whether the degree of urbanisation and its associated changes to stormwater runoff affected macroinvertebrate richness and abundance within constructed wetlands. Urban wetlands in Melbourne's west and south east were sampled along a gradient of urbanisation. There was a significant negative relationship between total imperviousness (TI) and the abundance of aquatic invertebrates detected for sites in the west, but not in the south east. However macroinvertebrate communities were relatively homogenous both within and between all study wetlands. Chironomidae (non-biting midges) was the most abundant family recorded at the majority of sites. Chironomids are able to tolerate a wide array of environmental conditions, including eutrophic and anoxic conditions. Their prevalence suggests that water quality is impaired in these systems, regardless of degree of urbanisation, although the causal mechanism is unclear. These results show some dependency between receiving wetland condition and the degree of urbanisation of the catchment, but suggest that other factors may be as important in determining the value of urban wetlands as habitat for wildlife.

  20. Responses of wetland plants to effluents in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Nguyen, M.T.; Esry, L.K.

    1991-01-01

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, seedling survival and growth in hydroponic culture, and seedling survival and growth in sand and synthetic sediments with clay, silt, and sand, 3, 5, 7.5, or 10% organic contents. There was no effect of effluents or herbicide on germination and survival was affected only by the herbicide. When compared to controls, growth rates were reduced significantly in all tests except for E. crusgalli exposed to effluent from a wastewater treatment plant. There, the effluent stimulated growth in sediments. Increasing concentrations of organic matter in sediments had little effect on toxicity of effluents, but did cause reduced effects of hexazinone.

  1. Phytoremediation of arsenic in submerged soil by wetland plants.

    PubMed

    Jomjun, Nateewattana; Siripen, Trichaiyaporn; Maliwan, Saeouy; Jintapat, Nateewattana; Prasak, Thavornyutikarn; Somporn, Choonluchanon; Petch, Pengchai

    2011-01-01

    Wetland aquatic plants including Canna glauca L., Colocasia esculenta L. Schott, Cyperus papyrus L. and Typha angustifolia L. were used in the phytoremediation of submerged soil polluted by arsenic (As). Cyperus papyrus L. was noticed as the largest biomass producer which has arsenic accumulation capacity of 130-172 mg As/kg plant. In terms of arsenic removal rate, however, Colocasia esculenta L. was recognized as the largest and fastest arsenic remover in this study. Its arsenic removal rate was 68 mg As/m2/day while those rates of Canna glauca L., Cyperus papyrus L. and Typha angustifolia L. were 61 mg As/m2/day, 56 mg As/m2/day, and 56 mg As/m2/day, respectively. Although the 4 aquatic plants were inferior in arsenic accumulation, their high arsenic removal rates were observed. Phytostabilization should be probable for the application of these plants. PMID:21598766

  2. The forms and bioavailability of phosphorus in integrated vertical flow constructed wetland with earthworms and different substrates.

    PubMed

    Xu, Defu; Wang, Lin; Li, Huili; Li, Yingxue; Howard, Alan; Guan, Yidong; Li, Jiuhai; Xu, Hui

    2015-09-01

    A sequential extraction method was utilized to analyze seven forms of P in an integrated vertical-flow constructed wetland (IVFCW) containing earthworms and different substrates. The aluminum-bound P (Al-P) content was found to be lower, and the occluded P (Oc-P) content was higher in the IVFCW. The addition of earthworms into the influent chamber of IVFCW increased the exchange P (Ex-P), iron-bound P (Fe-P), calcium bound P (Ca-P), Oc-P, detritus-bound (De-P) and organic P (Org-P) content in the influent chamber, and also enhanced P content uptake by wetland plants. A significantly positive correlation between P content of above-ground wetland plants and the Ex-P, Fe-P, Oc-P and Org-P content in the rhizosphere was found (P<0.05), which indicated that the Ex-P, Fe-P, Oc-P and Org-P could be bio-available P. The Ex-P, Fe-P, De-P, Oc-P and Ca-P content of the influent chamber was higher where the substrate contained a mixture of Qing sand and river sand rather than only river sand. Also the IVFCW with earthworms and both Qing sand and river sand had a higher removal efficiency of P, which was related to higher P content uptake by wetland plants and P retained in IVFCW. These findings suggest that addition of earthworms in IVFCW increases the bioavailable P content, resulting in enhanced P content uptake by wetland plants. PMID:26025066

  3. The forms and bioavailability of phosphorus in integrated vertical flow constructed wetland with earthworms and different substrates.

    PubMed

    Xu, Defu; Wang, Lin; Li, Huili; Li, Yingxue; Howard, Alan; Guan, Yidong; Li, Jiuhai; Xu, Hui

    2015-09-01

    A sequential extraction method was utilized to analyze seven forms of P in an integrated vertical-flow constructed wetland (IVFCW) containing earthworms and different substrates. The aluminum-bound P (Al-P) content was found to be lower, and the occluded P (Oc-P) content was higher in the IVFCW. The addition of earthworms into the influent chamber of IVFCW increased the exchange P (Ex-P), iron-bound P (Fe-P), calcium bound P (Ca-P), Oc-P, detritus-bound (De-P) and organic P (Org-P) content in the influent chamber, and also enhanced P content uptake by wetland plants. A significantly positive correlation between P content of above-ground wetland plants and the Ex-P, Fe-P, Oc-P and Org-P content in the rhizosphere was found (P<0.05), which indicated that the Ex-P, Fe-P, Oc-P and Org-P could be bio-available P. The Ex-P, Fe-P, De-P, Oc-P and Ca-P content of the influent chamber was higher where the substrate contained a mixture of Qing sand and river sand rather than only river sand. Also the IVFCW with earthworms and both Qing sand and river sand had a higher removal efficiency of P, which was related to higher P content uptake by wetland plants and P retained in IVFCW. These findings suggest that addition of earthworms in IVFCW increases the bioavailable P content, resulting in enhanced P content uptake by wetland plants.

  4. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan. Topical report, October 1990--August 1992

    SciTech Connect

    Rastorfer, J.R.; Van Dyke, G.D.; Zellmer, S.D.; Wilkey, P.L.

    1995-04-01

    This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth wetland sites mapped Lenawee soils were selected in Midland County, Michigan: Site 1, a younger stand subjected to recent selective logging, and Site 2, a more mature stand. The collection of ecological data to analyze plant succession on the right-of-way (ROW) and the effects of the developing ROW plant communities on adjacent forest communities was initiated in 1989. Cover class estimates were made for understory and ROW plant species on the basis of 1 {times} 1{minus}m quadrats. Individual stem diameters and species counts were recorded for overstory plants in 10{minus}m quadrats. Although long-term studies have not been completed, firm baseline data were established for comparative analyses with future sampling. Current data indicate that vegetation became well-established on the ROW within one year and subsequently increased in coverage. About 65% of the species were wetland indicators, and the dominants included seeded and natural invading species; nevertheless, some elements of the original flora regenerated and persist. The plants of the ecotone understories of both sites changed from their original composition as a result of the installation of the gas pipeline. Although some forest species persist at both sites, the ecotone of Site I was influenced more by the seeded species, whereas the natural invaders were more important at Site 2.

  5. Design configurations affecting flow pattern and solids accumulation in horizontal free water and subsurface flow constructed wetlands.

    PubMed

    Pedescoll, A; Sidrach-Cardona, R; Sánchez, J C; Carretero, J; Garfi, M; Bécares, E

    2013-03-01

    The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix.

  6. The performance of constructed wetlands for, wastewater treatment: a case study of Splash wetland in Nairobi Kenya

    NASA Astrophysics Data System (ADS)

    Nzengy'a, Daniel Muasya; Wishitemi, B. E. L.

    2001-12-01

    The performance of a constructed wetland for wastewater treatment was examined for four months (December 1995 to March 1996). The study area, hereby referred to as the Splash wetland, is approximately 0·5 ha, and is located in the southern part of Nairobi city. Splash wetland continuously receives domestic sewage from two busy restaurants. Treated wastewater is recycled for re-use for various purposes in the restaurants. Both wet and dry season data were analysed with a view of determining the impact of seasonal variation on the system performance. The physical and chemical properties of water were measured at a common intake and at series of seven other points established along the wetland gradient and at the outlet where the water is collected and pumped for re-use at the restaurants. The physico-chemical characteristics of the wastewater changed significantly as the wastewater flowed through the respective wetland cells. A comparison of wastewater influent versus the effluent from the wetland revealed the system's apparent success in water treatment, especially in pH modification, removal of suspended solids, organic load and nutrients mean influent pH = 5·7 +/- 0·5, mean effluent pH 7·7 +/- 0·3; mean influent BOD5 = 1603·0 +/- 397·6 mg/l, mean effluent BOD5 = 15·1 +/- 2·5 mg/l; mean influent COD = 3749·8 +/- 206·8 mg/l, mean effluent COD = 95·6 +/- 7·2 mg/l; mean influent TSS = 195·4 +/- 58·7 mg/l, mean effluent TSS = 4·7 +/- 1·9 mg/l. As the wastewater flowed through the wetland system dissolved free and saline ammonia, NH4+, decreased from 14·6 +/- 4·1 mg/l to undetectable levels at the outlet. Dissolved oxygen increased progressively through the wetland system. Analysis of the data available did not reveal temporal variation in the system's performance. However, significant spatial variation was evident as the wetland removed most of the common pollutants and considerably improved the quality of the water, making it safe for re-use at the

  7. Influence of environmental variables on the structure and composition of soil bacterial communities in natural and constructed wetlands.

    PubMed

    Arroyo, Paula; Sáenz de Miera, Luis E; Ansola, Gemma

    2015-02-15

    Bacteria are key players in wetland ecosystems, however many essential aspects regarding the ecology of wetland bacterial communities remain unknown. The present study characterizes soil bacterial communities from natural and constructed wetlands through the pyrosequencing of 16S rDNA genes in order to evaluate the influence of wetland variables on bacterial community composition and structure. The results show that the composition of soil bacterial communities was significantly associated with the wetland type (natural or constructed wetland), the type of environment (lagoon, Typha or Salix) and three continuous parameters (SOM, COD and TKN). However, no clear associations were observed with soil pH. Bacterial diversity values were significantly lower in the constructed wetland with the highest inlet nutrient concentrations. The abundances of particular metabolic groups were also related to wetland characteristics.

  8. Operational, design and microbial aspects related to power production with microbial fuel cells implemented in constructed wetlands.

    PubMed

    Corbella, Clara; Guivernau, Miriam; Viñas, Marc; Puigagut, Jaume

    2015-11-01

    This work aimed at determining the amount of energy that can be harvested by implementing microbial fuel cells (MFC) in horizontal subsurface constructed wetlands (HSSF CWs) during the treatment of real domestic wastewater. To this aim, MFC were implemented in a pilot plant based on two HSSF CW, one fed with primary settled wastewater (Settler line) and the other fed with the effluent of a hydrolytic up-flow sludge blanket reactor (HUSB line). The eubacterial and archaeal community was profiled on wetland gravel, MFC electrodes and primary treated wastewater by means of 16S rRNA gene-based 454-pyrosequencing and qPCR of 16S rRNA and mcrA genes. Maximum current (219 mA/m(2)) and power (36 mW/m(2)) densities were obtained for the HUSB line. Power production pattern correlated well with water level fluctuations within the wetlands, whereas the type of primary treatment implemented had a significant impact on the diversity and relative abundance of eubacteria communities colonizing MFC. It is worth noticing the high predominance (13-16% of relative abundance) of one OTU belonging to Geobacter on active MFC of the HUSB line that was absent for the settler line MFC. Hence, MFC show promise for power production in constructed wetlands receiving the effluent of a HUSB reactor.

  9. Operational, design and microbial aspects related to power production with microbial fuel cells implemented in constructed wetlands.

    PubMed

    Corbella, Clara; Guivernau, Miriam; Viñas, Marc; Puigagut, Jaume

    2015-11-01

    This work aimed at determining the amount of energy that can be harvested by implementing microbial fuel cells (MFC) in horizontal subsurface constructed wetlands (HSSF CWs) during the treatment of real domestic wastewater. To this aim, MFC were implemented in a pilot plant based on two HSSF CW, one fed with primary settled wastewater (Settler line) and the other fed with the effluent of a hydrolytic up-flow sludge blanket reactor (HUSB line). The eubacterial and archaeal community was profiled on wetland gravel, MFC electrodes and primary treated wastewater by means of 16S rRNA gene-based 454-pyrosequencing and qPCR of 16S rRNA and mcrA genes. Maximum current (219 mA/m(2)) and power (36 mW/m(2)) densities were obtained for the HUSB line. Power production pattern correlated well with water level fluctuations within the wetlands, whereas the type of primary treatment implemented had a significant impact on the diversity and relative abundance of eubacteria communities colonizing MFC. It is worth noticing the high predominance (13-16% of relative abundance) of one OTU belonging to Geobacter on active MFC of the HUSB line that was absent for the settler line MFC. Hence, MFC show promise for power production in constructed wetlands receiving the effluent of a HUSB reactor. PMID:26253894

  10. [Feasibility of treatment of landfill leachates by external loop three phase fluidized bed-constructed wetland system].

    PubMed

    Zhang, Jin-Sheng; Yuan, Xing-Zhong; Zeng, Guang-Ming; Dong, Bei-Bei; Liang, Yun-Shan

    2009-11-01

    In this study, the system composed with the external loop fluidized bed reactor and constructed wetland was used to treat the landfill leachate. The change of water quality for the landfill leachate treated by this system was investigated. The experimental results indicated that the COD and NH4(+) -N of the influent reduced from 4000 mg x L(-1) and 300 mg x L(-1) to 1 500 mg x L(-1) and 150 mg x L(-1) after the external loop three phase fluidized bed reactor and steady at 200 mg x L(-1) and 10 mg x L(-1) behind treated by the constructed wetland. The heavy metals of Cd, Zn, Pb were also reduced for treatment by external loop three phase fluidized bed reactor. They were steady at 0.01 mg x L(-1), 0.5 mg x L(-1), 0.1 mg x L(-1) from 0.12 mg x L(-1), 3.0 mg x L(-1), 1.4 mg x L(-1) because of the constructed wetland. We also compared the different plants for the efficiency, the results showed that whatever plants, there was little effects on the efficiency of the COD and NH4(+) -N, but the effect of heavy metal was markedness.

  11. Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

    SciTech Connect

    Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

    1999-10-01

    Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

  12. Landowners' incentives for constructing wetlands in an agricultural area in south Sweden.

    PubMed

    Hansson, Anna; Pedersen, Eja; Weisner, Stefan E B

    2012-12-30

    Eutrophication of the Baltic Sea has in Sweden led to the initiation of government schemes aiming to increase wetland areas in agricultural regions and thereby reduce nutrient transport to the sea. Landowners play a significant role as providers of this ecosystem service and are currently offered subsidies to cover their costs for constructing and maintaining wetlands. We undertook a grounded theory study, in which landowners were interviewed, aiming at identifying landowners' incentives for constructing wetlands on their land. The study showed that adequate subsidies, additional services that the wetland could provide to the landowner, local environmental benefits, sufficient knowledge, and peers' good experiences could encourage landowners to construct wetlands. Perceived hindrances were burdensome management, deficient knowledge, time-consuming application procedures and unclear effectiveness of nutrient reduction. The main reason for not creating a wetland, however, was that the land was classified as productive by the landowner, i.e., suitable for food production. Current schemes are directed toward landowners as individuals and based on subsidies to cover costs. We propose that landowners instead are approached as ecosystem service entrepreneurs and contracted after a tendering process based on nutrient reduction effects. This would lead to new definitions of production and may stimulate improved design and placement of wetlands. PMID:23064246

  13. Remediation of abandoned mine sites using constructed wetlands: A Colorado perspective

    SciTech Connect

    Ganse, M.A.; Herron, J.T.

    1995-09-01

    In recent years, constructed wetlands have been used to remediate acid mine drainage which has resulted from both coal and metal mining activities. These wetlands are use din conjunction with other engineered components to create a passive mine drainage treatment system (PMDT). Passive systems are designed to remediate mine drainage using minimum capital expenditures and little to no operational and maintenance costs. The Colorado Division of Minerals and Geology (DMG) is responsible for the design, construction, and operation of constructed wetlands in Colorado. Only 5 systems are in existence at this time, located in terrain varying from gentle foothills to remote, sub-alpine mountains. The design of a wetland system is based on a multitude of factors such as site terrain and access, mine drainage composition, and in the Rocky Mountain region, altitude. The impact of altitude, climate, terrain, and other physical site constraints on each wetland design will be discussed. In addition, chemical issues critical to the design of each wetland such as pH and alkalinity will be presented. Finally, the performance of each wetland system will be examined.

  14. Subsurface Treatment of Domestic Wastewater Using Single Domicile Constructed Wetlands

    NASA Astrophysics Data System (ADS)

    Aseltyne, T.; Steer, D.; Fraser, L.

    2001-05-01

    Analysis of one year of input versus output water quality monitoring data from nine household wastewater treatment wetlands in western Ohio indicates that these systems substantially reduce effluent loads delivered to the local watershed. Overall performance as measured by output water quality improvement varies widely between the nine systems despite their close proximity and identical design. These three-cell systems (septic tank with 2 subsurface wetland cells) are found to reduce biological oxygen demand (BOD) 70-98%, fecal coliform 60-99.9%, NH3 29-97%, Phosphorus 21-99.9% and total suspended solids (TSS) up to 97%. NO3/NO2 readings were only taken at the second wetland cell, but show that NO3/NO2 levels are at 0.005-5.01 mg/l and well below the USEPA standards for discharge from a wetland. On average, the pH of the wastewater increases from 6.6 at the septic tank to 8.7 at the wetland output. Nearly all the monitoring data indicate clear decreases in nutrient loads and bacteria though individual systems are found to non-systematically fail to meet EPA discharge guidelines for one or more of the monitored loads. Preliminary analysis of the data indicates a decrease in overall efficiency of the wetlands in April that may be related to seasonal factors. These systems will be monitored for the next three years in order to relate changing performance trends to seasonal variability.

  15. Ecosystem development after mangrove wetland creation: plant-soil change across a 20-year chronosequence

    USGS Publications Warehouse

    Osland, Michael J.; Spivak, Amanda C.; Nestlerode, Janet A.; Lessmann, Jeannine M.; Almario, Alejandro E.; Heitmuller, Paul T.; Russell, Marc J.; Krauss, Ken W.; Alvarez, Federico; Dantin, Darrin D.; Harvey, James E.; From, Andrew S.; Cormier, Nicole; Stagg, Camille L.

    2012-01-01

    Mangrove wetland restoration and creation efforts are increasingly proposed as mechanisms to compensate for mangrove wetland losses. However, ecosystem development and functional equivalence in restored and created mangrove wetlands are poorly understood. We compared a 20-year chronosequence of created tidal wetland sites in Tampa Bay, Florida (USA) to natural reference mangrove wetlands. Across the chronosequence, our sites represent the succession from salt marsh to mangrove forest communities. Our results identify important soil and plant structural differences between the created and natural reference wetland sites; however, they also depict a positive developmental trajectory for the created wetland sites that reflects tightly coupled plant-soil development. Because upland soils and/or dredge spoils were used to create the new mangrove habitats, the soils at younger created sites and at lower depths (10-30 cm) had higher bulk densities, higher sand content, lower soil organic matter (SOM), lower total carbon (TC), and lower total nitrogen (TN) than did natural reference wetland soils. However, in the upper soil layer (0-10 cm), SOM, TC, and TN increased with created wetland site age simultaneously with mangrove forest growth. The rate of created wetland soil C accumulation was comparable to literature values for natural mangrove wetlands. Notably, the time to equivalence for the upper soil layer of created mangrove wetlands appears to be faster than for many other wetland ecosystem types. Collectively, our findings characterize the rate and trajectory of above- and below-ground changes associated with ecosystem development in created mangrove wetlands; this is valuable information for environmental managers planning to sustain existing mangrove wetlands or mitigate for mangrove wetland losses.

  16. Seasonal effect on N2O formation in nitrification in constructed wetlands.

    PubMed

    Inamori, Ryuhei; Wang, Yanhua; Yamamoto, Tomoko; Zhang, Jixiang; Kong, Hainan; Xu, Kaiqin; Inamori, Yuhei

    2008-10-01

    Constructed wetlands are considered to be important sources of nitrous oxide (N(2)O). In order to investigate the contribution of nitrification in N(2)O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N(2)O emission and AOB amount. Nitrous oxide data showed large temporal and spatial fluctuations ranging 0-52.8 mg N(2)O m(-2)d(-1). Higher AOB amount and N(2)O flux rate were observed in the Zizania latifolia cell, reflecting high potential of global warming. Roles of plants as ecosystem engineers are summarized with rhizosphere oxygen release and organic matter transportation to affect nitrogen transformation. The Phragmites australis cell contributed to keeping high T-N removal performance and lower N(2)O emission. The distribution of AOB also supported this result. Statistical analysis showed several environmental parameters affecting the strength of observed greenhouse gases emission, such as water temperature, water level, TOC, plant species and plant cover. PMID:18782640

  17. Design and performance of the Champion pilot-constructed wetland treatment system

    SciTech Connect

    Knight, R.L. ); Hilleke, J.; Grayson, S. )

    1994-05-01

    Pilot wetlands were built at Champion International Corp.'s Pensacola, FL, bleached kraft paper mill to evaluate the potential for final effluent polishing. The pilot wetlands began operation July 1, 1991. Monitoring ended June 30, 1993. Removal rates and outflow concentrations for five-day biochemical oxygen demand (BOD[sub 5]), total suspended solids (TSS), ammonia nitrogen, total nitrogen (TN), and total phosphorus (TP) depended most on hydraulic loading rates (HLRs). Two-year average removal efficiencies for these constituents were above 67%. Slight color and total dissolved solids reductions were seen at the lower HLRs tested. Deep zones enhanced flow distribution, increase hydraulic residence time, and significantly increased pollutant assimilation in the pilot wetlands. The wetland cells reduced or eliminated chronic toxicity to cladocerans and fathead minnows. The most suitable plant species in the wetland were cattails, bulrush, and sawgrass.

  18. A review on the sustainability of constructed wetlands for wastewater treatment: Design and operation.

    PubMed

    Wu, Haiming; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Hu, Zhen; Liang, Shuang; Fan, Jinlin; Liu, Hai

    2015-01-01

    Constructed wetlands (CWs) have been used as a green technology to treat various wastewaters for several decades. CWs offer a land-intensive, low-energy, and less-operational-requirements alternative to conventional treatment systems, especially for small communities and remote locations. However, the sustainable operation and successful application of these systems remains a challenge. Hence, this paper aims to provide and inspire sustainable solutions for the performance and application of CWs by giving a comprehensive review of CWs' application and the recent development on their sustainable design and operation for wastewater treatment. Firstly, a brief summary on the definition, classification and application of current CWs was presented. The design parameters and operational conditions of CWs including plant species, substrate types, water depth, hydraulic load, hydraulic retention time and feeding mode related to the sustainable operation for wastewater treatments were then discussed. Lastly, future research on improving the stability and sustainability of CWs were highlighted.

  19. Assessing environmental impacts of constructed wetland effluents for vegetable crop irrigation.

    PubMed

    Castorina, A; Consoli, S; Barbagallo, S; Branca, F; Farag, A; Licciardello, F; Cirelli, G L

    2016-01-01

    The objective of this study was to monitor and assess environmental impacts of reclaimed wastewater (RW), used for irrigation of vegetable crops, on soil, crop quality and irrigation equipment. During 2013, effluents of a horizontal sub-surface flow constructed treatment wetland (TW) system, used for tertiary treatment of sanitary wastewater from a small rural municipality located in Eastern Sicily (Italy), were reused by micro-irrigation techniques to irrigate vegetable crops. Monitoring programs, based on in situ and laboratory analyses were performed for assessing possible adverse effects on water-soil-plant systems caused by reclaimed wastewater reuse. In particular, experimental results evidenced that Escherichia coli content found in RW would not present a risk for rotavirus infection following WHO (2006) standards. Irrigated soil was characterized by a certain persistence of microbial contamination and among the studied vegetable crops, lettuce responds better, than zucchini and eggplants, to the irrigation with low quality water, evidencing a bettering of nutraceutical properties and production parameters.

  20. Structural characterization of organic intermediates arising from xylenol degradation by laboratory-scale constructed wetlands.

    PubMed

    Poerschmann, J; Schultze-Nobre, L

    2014-08-01

    A mixture of xylenols (2,6-, 3,4-, 3,5-) was subjected to laboratory-scale constructed wetland treatment using helophytes. Conversion efficiencies under aerobic conditions ranged from 89% to 94%; the corresponding numbers under anaerobic conditions were lower. The studies were focused on the identification of stable organic intermediates. Identification was performed by a combination of GC/MS analysis and pre-chromatographic derivatization of the lyophilizates. In addition to common intermediates including citraconate, succinate and dimethyl benzenediols, an array of α- and β-ketoadipic acid carboxylates could be identified. The ketoadipic acid carboxylates have not been known to be formed in bioremediation of phenols including xylenols so far. Mechanisms for the formation of ketoadipic acid carboxylates are proposed. Chemotaxonomic considerations using diagnostic fatty acids provided mounting evidence that organic matter originating from plants prevailed over bacterial organic matter. Biomarkers indicated a virtual absence of fungi and algae. PMID:24393564

  1. A review on the sustainability of constructed wetlands for wastewater treatment: Design and operation.

    PubMed

    Wu, Haiming; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Hu, Zhen; Liang, Shuang; Fan, Jinlin; Liu, Hai

    2015-01-01

    Constructed wetlands (CWs) have been used as a green technology to treat various wastewaters for several decades. CWs offer a land-intensive, low-energy, and less-operational-requirements alternative to conventional treatment systems, especially for small communities and remote locations. However, the sustainable operation and successful application of these systems remains a challenge. Hence, this paper aims to provide and inspire sustainable solutions for the performance and application of CWs by giving a comprehensive review of CWs' application and the recent development on their sustainable design and operation for wastewater treatment. Firstly, a brief summary on the definition, classification and application of current CWs was presented. The design parameters and operational conditions of CWs including plant species, substrate types, water depth, hydraulic load, hydraulic retention time and feeding mode related to the sustainable operation for wastewater treatments were then discussed. Lastly, future research on improving the stability and sustainability of CWs were highlighted. PMID:25453440

  2. Optimizations on supply and distribution of dissolved oxygen in constructed wetlands: A review.

    PubMed

    Liu, Huaqing; Hu, Zhen; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Fan, Jinlin; Lu, Shaoyong; Wu, Haiming

    2016-08-01

    Dissolved oxygen (DO) is one of the most important factors that can influence pollutants removal in constructed wetlands (CWs). However, problems of insufficient oxygen supply and inappropriate oxygen distribution commonly exist in traditional CWs. Detailed analyses of DO supply and distribution characteristics in different types of CWs were introduced. It can be concluded that atmospheric reaeration (AR) served as the promising point on oxygen intensification. The paper summarized possible optimizations of DO in CWs to improve its decontamination performance. Process (tidal flow, drop aeration, artificial aeration, hybrid systems) and parameter (plant, substrate and operating) optimizations are particularly discussed in detail. Since economic and technical defects are still being cited in current studies, future prospects of oxygen research in CWs terminate this review.

  3. Constructed wetland as an ecotechnological tool for pollution treatment for conservation of Ganga river.

    PubMed

    Rai, U N; Tripathi, R D; Singh, N K; Upadhyay, A K; Dwivedi, S; Shukla, M K; Mallick, S; Singh, S N; Nautiyal, C S

    2013-11-01

    With aim to develop an efficient and ecofriendly approach for on-site treatment of sewage, a sub-surface flow constructed wetland (CW) has been developed by raising potential aquatic macrophytes; Typha latifolia, Phragmites australis, Colocasia esculenta, Polygonum hydropiper, Alternanthera sessilis and Pistia stratoites in gravel as medium. Sewage treatment potential of CW was evaluated by varying retention time at three different stages of plant growth and stabilization. After 6 months, monitoring of fully established CW indicated reduction of 90%, 65%, 78%, 84%, 76% and 86% of BOD, TSS, TDS, NO3-N, PO4-P and NH4-N, respectively in comparison to inlet after 36 h of retention time. Sewage treatment through CW also resulted in reduction of heavy metal contents. Thus, CW proved an effective method for treatment of wastewater and may be developed along river Ganga stretch as an alternative technology. Treated water may be drained into river to check further deterioration of Ganga water quality. PMID:24080292

  4. Constructed wetland as an ecotechnological tool for pollution treatment for conservation of Ganga river.

    PubMed

    Rai, U N; Tripathi, R D; Singh, N K; Upadhyay, A K; Dwivedi, S; Shukla, M K; Mallick, S; Singh, S N; Nautiyal, C S

    2013-11-01

    With aim to develop an efficient and ecofriendly approach for on-site treatment of sewage, a sub-surface flow constructed wetland (CW) has been developed by raising potential aquatic macrophytes; Typha latifolia, Phragmites australis, Colocasia esculenta, Polygonum hydropiper, Alternanthera sessilis and Pistia stratoites in gravel as medium. Sewage treatment potential of CW was evaluated by varying retention time at three different stages of plant growth and stabilization. After 6 months, monitoring of fully established CW indicated reduction of 90%, 65%, 78%, 84%, 76% and 86% of BOD, TSS, TDS, NO3-N, PO4-P and NH4-N, respectively in comparison to inlet after 36 h of retention time. Sewage treatment through CW also resulted in reduction of heavy metal contents. Thus, CW proved an effective method for treatment of wastewater and may be developed along river Ganga stretch as an alternative technology. Treated water may be drained into river to check further deterioration of Ganga water quality.

  5. Vegetation survey of Four Mile Creek wetlands. [Savannah River Plant

    SciTech Connect

    Loehle, C.

    1990-11-01

    A survey of forested wetlands along upper Four Mile Creek was conducted. The region from Road 3 to the creek headwaters was sampled to evaluate the composition of woody and herbaceons plant communities. All sites were found to fall into either the Nyssa sylvatica (Black Gum) -- Persea borbonia (Red Bay) or Nyssa sylvatica -- Acer rubrum (Red Maple) types. These community types are generally species-rich and diverse. Previous studies (Greenwood et al., 1990; Mackey, 1988) demonstrated contaminant stress in areas downslope from the F- and H-Area seepage basins. In the present study there were some indications of contaminant stress. In the wetland near H-Area, shrub basal area, ground cover stratum species richness, and diversity were low. In the area surrounding the F-Area tree kill zone, ground cover stratum cover and shrub basal area were low and ground cover stratum species richness was low. The moderately stressed site at F-Area also showed reduced overstory richness and diversity and reduced ground cover stratum richness. These results could, however, be due to the very high basal area of overstory trees in both stressed F-Area sites that would reduce light availability to understory plants. No threatened or endangered plant species were found in the areas sampled. 40 refs., 4 figs., 8 tabs.

  6. Potential for using native plant species in stormwater wetlands.

    PubMed

    Bonilla-Warford, Cristina M; Zedler, Joy B

    2002-03-01

    Spartina pectinata (prairie cordgrass) was grown under five hydroperiods (wet-dry cycles) to determine its potential for use in stormwater wetlands, particularly as an alternative to the highly invasive Phalaris arundinacea (an exotic grass). Rhizomes planted in outdoor microcosms grew vigorously in all treatments, namely, weekly flooding in early summer, weekly flooding in late summer, flooding every three weeks throughout the summer, weekly flooding throughout the summer, and no flooding. Neither the timing nor frequency of 24-hour floods (10-20 cm deep) affected total stem length (grand mean 1003 +/- 188.8 cm per pot, n = 140) or above-ground biomass (46.5 +/- 8.3 g per pot, equivalent to approximately 360 g/m2). However, by late summer, fewer new tillers were found in unflooded microcosms, indicating that vegetative expansion is drought-sensitive. The growth of Spartina plants was further assessed with and without Glyceria striata (a native grass) and Phalaris arundinacea. Glyceria growth was not affected by hydrologic treatment. Glyceria reduced Spartina growth by approximately 11%, suggesting potential as a cover crop that might reduce establishment and growth of Phalaris seedlings. Seeds of Phalaris did not germinate, but branch fragments established where soil was moist from flooding, regardless of the presence of Glyceria. The ability of Spartina to establish vegetatively and grow well under variable water levels leads us to recommend further testing in stormwater wetlands, along with early planting of Glyceria to reduce weed invasions.

  7. Treatment of industrial effluents in constructed wetlands: challenges, operational strategies and overall performance.

    PubMed

    Wu, Shubiao; Wallace, Scott; Brix, Hans; Kuschk, Peter; Kirui, Wesley Kipkemoi; Masi, Fabio; Dong, Renjie

    2015-06-01

    The application of constructed wetlands (CWs) has significantly expanded to treatment of various industrial effluents, but knowledge in this field is still insufficiently summarized. This review is accordingly necessary to better understand this state-of-the-art technology for further design development and new ideas. Full-scale cases of CWs for treating various industrial effluents are summarized, and challenges including high organic loading, salinity, extreme pH, and low biodegradability and color are evaluated. Even horizontal flow CWs are widely used because of their passive operation, tolerance to high organic loading, and decolorization capacity, free water surface flow CWs are effective for treating oil field/refinery and milking parlor/cheese making wastewater for settlement of total suspended solids, oil, and grease. Proper pretreatment, inflow dilutions through re-circulated effluent, pH adjustment, plant selection and intensifications in the wetland bed, such as aeration and bioaugmentation, are recommended according to the specific characteristics of industrial effluents.

  8. Treatment of industrial effluents in constructed wetlands: challenges, operational strategies and overall performance.

    PubMed

    Wu, Shubiao; Wallace, Scott; Brix, Hans; Kuschk, Peter; Kirui, Wesley Kipkemoi; Masi, Fabio; Dong, Renjie

    2015-06-01

    The application of constructed wetlands (CWs) has significantly expanded to treatment of various industrial effluents, but knowledge in this field is still insufficiently summarized. This review is accordingly necessary to better understand this state-of-the-art technology for further design development and new ideas. Full-scale cases of CWs for treating various industrial effluents are summarized, and challenges including high organic loading, salinity, extreme pH, and low biodegradability and color are evaluated. Even horizontal flow CWs are widely used because of their passive operation, tolerance to high organic loading, and decolorization capacity, free water surface flow CWs are effective for treating oil field/refinery and milking parlor/cheese making wastewater for settlement of total suspended solids, oil, and grease. Proper pretreatment, inflow dilutions through re-circulated effluent, pH adjustment, plant selection and intensifications in the wetland bed, such as aeration and bioaugmentation, are recommended according to the specific characteristics of industrial effluents. PMID:25792030

  9. Transport and transformation of de-icing urea from airport runways in a constructed wetland system.

    PubMed

    Thorén, A K; Legrand, C; Herrmann, J

    2003-01-01

    Urea, NH2-CO-NH2, is used as a de-icing agent at Kalmar Airport, southeast Sweden. During 1998-2001, urea contributed on average 30% of the yearly nitrogen (N) transport of 41,000 kg via Törnebybäcken stream to the coastal zone of the Baltic Sea. In order to reduce stream transport of N from airport, agricultural and other diffuse sources, a wetland was constructed in 1996. Annual wetland retention of total-N varied in the range of 2,500-8,100 kg (6-36% of influent) during 1998-2001, according to mass balances calculated from monthly sampling. During airport de-icing, January-March 2001,660 kg urea-N out of 2,600 kg applied urea-N reached the wetland according to daily sampling. This indicated that 75% of the urea was transformed before entering the wetland. Urea was found to be only a minor part (8%) of total-N in the wetland influent. Calculations of cumulative urea-N loads at the wetland inlet and outlet respectively, showed a significant urea transformation during February 2001 with approximately 40% of the incoming urea-N being transformed in the wetland system. These results show that significant amounts of urea can be transformed in a wetland system at air temperatures around 0 degree C. PMID:14621175

  10. Modeling the effects of constructed wetland on nonpoint source pollution control and reservoir water quality improvement.

    PubMed

    Ham, Jonghwa; Yoon, Chun G; Kim, Hyung-Joong; Kim, Hyung-Chul

    2010-01-01

    This article describes the integrated modeling approach for planning the size and the operation of constructed wetlands for maximizing retention of nonpoint source pollutant loads and reservoir water-quality improvement at a catchment scale. The experimental field-scale wetland systems (four sets, 0.88 ha each) have been in operation since 2002, where water depth was maintained at 30-50 cm and hydraulic loading rate was at 6.3-18.8 cm/day. The wetland system was found to be adequate for treating polluted stream water with stable removal efficiency even during the winter. The integrated modeling system (modified-BASINS) was applied to the Seokmoon estuarine reservoir watershed and calibrated with monitoring data from constructed wetland, stream, and reservoir. The calibrated integrated modeling system estimated that constructing wetlands on 0.5% (about 114 ha) of the watershed area at the mouth of reservoir could reduce 11.61% and 13.49% of total external nitrogen and phosphorus loads, respectively. It also might improve the nitrogen and phosphorus concentration of the reservoir by 9.69% and 16.48%, respectively. The study suggested that about 0.1%-1.0% of the watershed area should be allocated for constructed wetland to meet specified water-quality standards for the estuarine reservoir at the polder area where land use planning is relatively less complicated.

  11. Comparison of Constructed Wetland Mesocosms Designed for Treatment of Copper-Contaminated Wastewater

    SciTech Connect

    Gladden, J.B.

    2001-02-15

    This study compared the performance of two constructed wetland mesocosms used to model a full-scale wetland system designed for treatment of copper-contaminated wastewater. One mesocosm (designated site-specific) was built near the construction site of the full-scale wetland using on-site soil, commercially available vegetation [Scirpus californicus (C.A. Meyer) Steud.], and water from the targeted wastestream. A second mesocosm (designated generic) was constructed at Clemson University using local soil, cultured S. californicus, and local municipal water amended with CuSO{sub 4}. Performance objectives were to achieve 22 m g/L total copper and no toxicity (Ceriodaphnia dubia Richard, 7-d/static/ renewal) in wetland outflows. Total inflow copper to the site-specific and generic mesocosms ranged from non-detect to 87 {micro} g/L and from 27 to 68 {micro} g/L, respectively. Overall total copper removal was 40% ({+-}33) for the site-specific mesocosm and 73% ({+-}14) for the generic mesocosm. In seven of nine monthly toxicity tests, C. dubia reproduction was significantly decreased ({alpha} = 0.05) in outflow of the site-specific mesocosm. No outflow toxicity was observed for the generic mesocosm. Although performance of the two mesocosms differed, both studies contributed to full-scale design by highlighting critical aspects of wetland function and augmenting operation and maintenance plans, enhancing overall constructed wetland design.

  12. Design of pilot-scale constructed wetlands for tertiary treatment of refinery effluent

    SciTech Connect

    Dorn, P.B.; Vergel, N.R.; Hawkins, W.B.; Dunn, A.; Rodgers, J.H. Jr.

    1994-12-31

    Two pilot-scale constructed wetlands (4:1 length:width aspect) were designed for tertiary treatment of refinery effluent. As requirements for removal of contaminants from NPDES effluents become more stringent, cost-effective technological approaches are needed to achieve the necessary treatment levels and be efficient, effective and low maintenance. The fundamental design of these constructed wetlands was based on biogeochemical principles that regulate the fate and persistence of the targeted elements (Cu, Zn, Pb). In order to maximize opportunities to learn more about the internal function of the wetlands, they were built to operate in series or in parallel permitting hydraulic retention times of 24 to 48 hours. The wetlands were lined with {approximately}76 cm of compacted clay as well as a 30 mil polyethylene liner. The hydrosoil selected for use in the constructed wetlands is 74.1% sand, 25.6% silt, 0.3% clay. Based on laboratory studies, this hydrosoil achieves a redox of 250 to {approximately}300 mv and a pH of 7.5 in the presence of Scirpus californicus. These conditions should enhance the ability of the constructed wetlands to retain and sequester the target elements and control chronic toxicity from the effluent.

  13. Nitrogen removal and greenhouse gas emissions from constructed wetlands receiving tile drainage water.

    PubMed

    Groh, Tyler A; Gentry, Lowell E; David, Mark B

    2015-05-01

    Loss of nitrate from agricultural lands to surface waters is an important issue, especially in areas that are extensively tile drained. To reduce these losses, a wide range of in-field and edge-of-field practices have been proposed, including constructed wetlands. We re-evaluated constructed wetlands established in 1994 that were previously studied for their effectiveness in removing nitrate from tile drainage water. Along with this re-evaluation, we measured the production and flux of greenhouse gases (GHGs) (CO, NO, and CH). The tile inlets and outlets of two wetlands were monitored for flow and N during the 2012 and 2013 water years. In addition, seepage rates of water and nitrate under the berm and through the riparian buffer strip were measured. Greenhouse gas emissions from the wetlands were measured using floating chambers (inundated fluxes) or static chambers (terrestrial fluxes). During this 2-yr study, the wetlands removed 56% of the total inlet nitrate load, likely through denitrification in the wetland. Some additional removal of nitrate occurred in seepage water by the riparian buffer strip along each berm (6.1% of the total inlet load, for a total nitrate removal of 62%). The dominant GHG emitted from the wetlands was CO, which represented 75 and 96% of the total GHG emissions during the two water years. The flux of NO contributed between 3.7 and 13% of the total cumulative GHG flux. Emissions of NO were 3.2 and 1.3% of the total nitrate removed from wetlands A and B, respectively. These wetlands continue to remove nitrate at rates similar to those measured after construction, with relatively little GHG gas loss.

  14. Floodplain/wetland assessment of the effects of construction and operation ofa depleted uranium hexafluoride conversion facility at the Paducah, Kentucky,site.

    SciTech Connect

    Van Lonkhuyzen, R.

    2005-09-09

    The U.S. Department of Energy (DOE) Depleted Uranium Hexafluoride (DUF{sub 6}) Management Program evaluated alternatives for managing its inventory of DUF{sub 6} and issued the ''Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride'' (DUF{sub 6} PEIS) in April 1999 (DOE 1999). The DUF{sub 6} inventory is stored in cylinders at three DOE sites: Paducah, Kentucky; Portsmouth, Ohio; and East Tennessee Technology Park (ETTP), near Oak Ridge, Tennessee. In the Record of Decision for the DUF{sub 6} PEIS, DOE stated its decision to promptly convert the DUF{sub 6} inventory to a more stable chemical form. Subsequently, the U.S. Congress passed, and the President signed, the ''2002 Supplemental Appropriations Act for Further Recovery from and Response to Terrorist Attacks on the United States'' (Public Law No. 107-206). This law stipulated in part that, within 30 days of enactment, DOE must award a contract for the design, construction, and operation of a DUF{sub 6} conversion plant at the Department's Paducah, Kentucky, and Portsmouth, Ohio, sites, and for the shipment of DUF{sub 6} cylinders stored at ETTP to the Portsmouth site for conversion. This floodplain/wetland assessment has been prepared by DOE, pursuant to Executive Order 11988 (''Floodplain Management''), Executive Order 11990 (Protection of Wetlands), and DOE regulations for implementing these Executive Orders as set forth in Title 10, Part 1022, of the ''Code of Federal Regulations'' (10 CFR Part 1022 [''Compliance with Floodplain and Wetland Environmental Review Requirements'']), to evaluate potential impacts to floodplains and wetlands from the construction and operation of a conversion facility at the DOE Paducah site. Reconstruction of the bridge crossing Bayou Creek would occur within the Bayou Creek 100-year floodplain. Replacement of bridge components, including the bridge supports, however, would not be expected to

  15. Performance of microbial fuel cell coupled constructed wetland system for decolorization of azo dye and bioelectricity generation.

    PubMed

    Fang, Zhou; Song, Ha