Plants In Constructed Wetlands Research Articles

Antitumor Constituents of the Wetland Plant Nymphoides peltata: A Case Study for the Potential Utilization of Constructed Wetland Plant Resources

The efficient utilization of plant resources is a necessary and important measure for sustainable management of constructed wetlands. Screening bioactive metabolites from wetland plants could reveal potential solutions for the utilization of constructed wetland plant resources. In this study, the constructed wetland macrophyte Nymphoides peltata was screened for constituents with antitumor activity. The secondary metabolites of N. peltata were extracted and separated by MCI gel, silica gel, and Sephadex gel column chromatography. Antitumor tests were then carried out with MTT assay against the human prostate cancer cell PC3 and the human osteosarcoma cell U2OS. The secondary metabolite group with the most significant antitumor activity was further examined, and four constituents were obtained and identified. This study provides a scientific basis for the potential efficient utilization of N. peltata and other constructed wetland plant resources.

Microbial nitrogen transformation in constructed wetlands treating contaminated groundwater

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.

Removal of selected organic micropollutants in planted and unplanted pilot-scale horizontal flow constructed wetlands under conditions of high organic load

The aim of this study was to investigate the removal of eleven selected organic micropollutants (OMPs) occurring in municipal wastewater in a 1–100μgL−1 concentration range during the treatment in two (planted and unplanted) pilot-scale horizontal subsurface flow constructed wetlands in order to elucidate (i) the role of plants on the mass removal and (ii) to understand the removal behavior of the micropollutants at different sampling locations along the flow path. The research was conducted in Langenreichenbach (Saxony), Germany, over a period of one year. The high organic load was chosen for both constructed wetlands (CWs) to study the removal of OMPs, because it is often occurring in the “real” world, but seldom investigated as a research objective.The concentration of the OMPs in the treated inflow wastewater varied more strongly (by a factor of 10) than the total organic and nitrogen loads (by a factor of 4). A wide range of removal efficiencies were found. Higher removals were observed in the pilot-scale CW planted with Phragmites australis than in the unplanted one. The stimulant caffeine was the investigated OMP which showed the highest removal with an average efficiency of 66%. The average removal efficiency of the other OMPs was below 30%. The plants in the CWs supported not only the removal of the fragrances galaxolide and tonalide but also the removal of the pharmaceuticals carbamazepine, diclofenac, ibuprofen, ketoprofen and naproxen, even under the conditions of high organic load. The endocrine disruptors bisphenol A and nonylphenol, and the antibacterial triclosan showed on average the lowest removal efficiencies. Under the studied operating conditions of high load, a positive correlation between the internal removal behavior of naproxen and diclofenac and concentration of sulfide was found.

Study on the Effects of Wastewater Duress on Chlorophyll Content of 4 Species Wetland Plants

The research which is the species selection of constructed wetland plants and the resistance of the plants is the key to ecological wastewater treatment technology. This paper studies the change of chlorophyll content in 4 wetland plants (Phragmites communis, Typha orientalis, Arundo donax and Canna generalis) in different wastewater duress time. The results show: chlorophyll contents in Canna generalis and Arundo donax have less change, and their anti-stress capability are stronger.

The feasibility of using constructed wetlands plants to produce bioethanol

The feasibility of using different constructed wetlands (CWs) plants for production of ethanol was investigated. Pretreatment of different dried materials with 1% (wt/vol) NaOH was followed by solid–liquid separation and enzymatic hydrolysis, then fermentated with Pichia stipitis. Five type of sugar were detected in the hydrolysis, including glucose, xylose, and other three unknown sugars. Aspidistra elatior showed the highest total sugar yield (86.60%), and Thalia dealbata showed the lowest yield (23.65%). The highest ethanol production was 8.27, 6.47, and 5.97 g/100 g dry mass from Iris pseudacorus Linn, Zantedeschia aethiopica Spreng, and Eichhornia crassipes, respectively. And the theoretical ethanol yield was 53.78%, 90.78%, and 80.65%. A satisfactory value in comparison to the data from corn stover (7.92 g/100 g dry mass and 49.17% theoretical ethanol yield). However, Nephrolepis auriculata and Veronica undulata Wall couldn't produce ethanol in our work. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 276–281, 2015

Study on the Effects of Domestic Sewage on Soluble Protein Content of Parts Constructed Wetland Plants

The study on the resistance of different wetland plants to wastewater duress is the key to ecological wastewater treatment technology. This paper studies the change of soluble protein content in 4 common wetland plants (Phragmites communis, Typha angustata, Arundo donax and Canna generalis) in Shandong in different wastewater duress time. The results show: when the wastewater duress time is 2 days and 4 days, soluble protein content in Phragmites communis has minimal change, and its anti-stress capability is the strongest; when the wastewater duress time is 6 days, soluble protein content in Canna generalis has minimal change, and its anti-stress capability is the strongest, followed by Typha angustata.

Screening anti-tumor constituents from <em>Potamogeton crispus</em> for potential utilisation of constructed wetland plant resources

Potamogeton crispus L. is a cosmopolitan aquatic macrophyte that has been deployed in constructed wetland as engineering species for ecological and purification functions. However, the extraordinary rapid vegetative growth of P. crispus requires that the species be harvested at the appropriate time to ensure the effectiveness of pollutant removal and minimise the risk of secondary pollution. The efficiency utilisation of wetland plant resources with a large amount of biomass is important in encouraging the harvest and sustainable self-support management of constructed wetlands. To screen the metabolites of P. crispus for tumor cell cytotoxicity, the total secondary metabolites of P. crispus were extracted and separated into three parts by using petroleum ether, ethyl acetate (EtOAc), and n-butyl alcohol. Thereafter, the cytotoxicity assay was conducted by using ES-2 human ovarian cancer and MDA-MB-231 human breast cancer cell lines. Results indicated that the P. crispus EtOAc extract showed anti-tumor activities against MDA-MB-231 cells. Morphological observation, cell cycle, and death analysis were conducted to evaluate the cytotoxic activity. Results showed that the P. crispus EtOAc extract could change the cell morphology and block the MDA-MB-231 cell cycle at the S phase and that the mechanisms of cell death were apoptosis and necrosis. This study provides a scientific basis for the potential utilisation of the constructed wetland plant P. crispus and has implications for the management of sustainable constructed wetland operation.

Screening anti-tumor constituents from Potamogeton crispus for potential utilisation of constructed wetland plant resources

Potamogeton crispus L. is a cosmopolitan aquatic macrophyte that has been deployed in constructed wetland as engineering species for ecological and purification functions. However, the extraordinary rapid vegetative growth of P. crispus requires that the species be harvested at the appropriate time to ensure the effectiveness of pollutant removal and minimise the risk of secondary pollution. The efficiency utilisation of wetland plant resources with a large amount of biomass is important in encouraging the harvest and sustainable self-support management of constructed wetlands. To screen the metabolites of P. crispus for tumor cell cytotoxicity, the total secondary metabolites of P. crispus were extracted and separated into three parts by using petroleum ether, ethyl acetate (EtOAc), and n-butyl alcohol. Thereafter, the cytotoxicity assay was conducted by using ES-2 human ovarian cancer and MDA-MB-231 human breast cancer cell lines. Results indicated that the P. crispus EtOAc extract showed anti-tumor activities against MDA-MB-231 cells. Morphological observation, cell cycle, and death analysis were conducted to evaluate the cytotoxic activity. Results showed that the P. crispus EtOAc extract could change the cell morphology and block the MDA-MB-231 cell cycle at the S phase and that the mechanisms of cell death were apoptosis and necrosis. This study provides a scientific basis for the potential utilisation of the constructed wetland plant P. crispus and has implications for the management of sustainable constructed wetland operation.

Removal of Heavy Metal Elements and Nutrients by <I>Pontederia cordata</I> and <I>Phragmites australis</I> Constructed Wetlands

For studying the potential applications of Pontederia cordata L.as a constructed wetland plant,the removal effects of P.cordata and Phragmites australis Trin.ex Steud.on nutrients and heavy metal elements in the wetlands were compared.Mono-cultivated small-scale wetlands were constructed using pots(80 cm-50 cm-45 cm,the upper diameter-bottom diameter-high).The results showed that the removal rates for TN and BOD5 by P.cordata was significantly higher than those by P.australis(P 0.05).But there was no significant difference between them for the removal of Cd2 + and Pb2+.Content distribution of Cd2+and Pb2+ in both plants was as follows: root stem leaf.For both the wetlands,there was little difference in nutrient removal between hydraulic retention time(HRT) of 2 d and 7 d,but heavy metal removal rate at HRT of 7 d was significantly higher than that at HRT of 2 d,indicating that the removal of heavy metals was slower than that of nutrients in the constructed wetlands.These results suggest that P.cordata has a good application potential in constructed wetlands because of its good visual effects and high removal rates for wastewater pollutants.

Biological Cr(VI) removal using bio-filters and constructed wetlands

The bioreduction of hexavalent chromium from aqueous solution was carried out using suspended growth and packed-bed reactors under a draw-fill operating mode, and horizontal subsurface constructed wetlands. Reactors were inoculated with industrial sludge from the Hellenic Aerospace Industry using sugar as substrate. In the suspended growth reactors, the maximum Cr(VI) reduction rate (about 2 mg/L h) was achieved for an initial concentration of 12.85 mg/L, while in the attached growth reactors, a similar reduction rate was achieved even with high initial concentrations (109 mg/L), thus confirming the advantage of these systems. Two horizontal subsurface constructed wetlands (CWs) pilot-scale units were also built and operated. The units contained fine gravel. One unit was planted with common reeds and one was kept unplanted. The mean influent concentrations of Cr(VI) were 5.61 and 5.47 mg/L for the planted and unplanted units, respectively. The performance of the planted CW units was very effective as mean Cr(VI) removal efficiency was 85% and efficiency maximum reached 100%. On the contrary, the unplanted CW achieved very low Cr(VI) removal with a mean value of 26%. Both attached growth reactors and CWs proved efficient and viable means for Cr(VI) reduction.

Study of Constructed Wetland Plant Growth by Computer Image Processing (CIP)

This paper developed a kind of non-destructive measurement for the growth process of constructed wetland plant: doing image acquisitions of constructed wetland plant regularly through digital camera imaging; introducing image files to computer through interface, displaying them on the screen of computer; developed constructed wetland plant image and growth information extraction software under Visual C++ compiling integrated environment, users could acquire plant contour (realized by image edge recognition) and plant size (characterized by top projected leaf area) through human-machine interactive operation; designed constructed wetland plant (Phragmites communis) experiment to analyze the biomass change during the non-destructive measurement process. The biomass had good correlation with manual measured individual plant height, which proved that computer image processing based non-destructive measurement can provide reliable predictions for plant growth parameters.

Study of Constructed Wetland Plant Growth by Computer Image Processing (CIP)

This paper developed a kind of non-destructive measurement for the growth process of constructed wetland plant: doing image acquisitions of constructed wetland plant regularly through digital camera imaging; introducing image files to computer through interface, displaying them on the screen of computer; developed constructed wetland plant image and growth information extraction software under Visual C++ compiling integrated environment, users could acquire plant contour (realized by image edge recognition) and plant size (characterized by top projected leaf area) through human-machine interactive operation; designed constructed wetland plant (Phragmites communis) experiment to analyze the biomass change during the non-destructive measurement process. The biomass had good correlation with manual measured individual plant height, which proved that computer image processing based non-destructive measurement can provide reliable predictions for plant growth parameters.

Decontamination efficiency and root structure change in the plant-intercropping model in vertical-flow constructed wetlands

Subtropical climatic conditions can contribute to the death of the aerial parts of constructed wetland plants in winter. This presents a barrier to the widespread application of constructed wetland and is an issue that urgently needs to be solved. Three contrasting experiments, the plant-intercropping model (A), the warm-seasonal plant model (B), and the non-plant model (C), were studied in terms of their efficiency in removing pollutants, and the change in root structure of plants in the plant-intercropping model within the vertical-flow constructed wetlands. The results indicate that model A was able to solve the aforementioned problem. Overall, average removal rates of three pollutants (CODCr, total nitrogen (TN) and total phosphorous (TP)) using model A were significantly higher than those obtained using models B and C (P 0.05). Conversely, removal rates of the three pollutants were found to be significantly higher using model A than those observed using model B during the lower temperature part of the year (P<0.01). Furthermore, the morphologies and internal structures of plant roots further demonstrate that numerous white roots, whose distribution in soil was generally shallow, extend further under model A. The roots of these aquatic plants have an aerenchyma structure composed of parenchyma cells, therefore, roots of the cold-seasonal plants with major growth advantages used in A were capable of creating a more favorable vertical-flow constructed wetlands mediamicroenvironment. In conclusion, the plant-intercropping model (A) is more suitable for use in the cold environment experienced by constructed wetland during winter.

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

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.

Mass Balance Study on Phosphorus Removal in Constructed Wetland Microcosms Treating Polluted River Water

AbstractA number of studies have showed that the mass removal rates of phosphorus (P) in different constructed wetlands (CWs) varied significantly, and it is essential to quantify the contributions of major P removal processes in order to improve system design. The objective of this study was to investigate the effects of vegetation, hydraulic retention time (HRT), and water temperature on P removal from polluted river water and to quantify the contributions of different P removal pathways in surface CWs. Results showed that the average total P removal rates ranged between 2.69 and 20.84 mg/(m2 day) in different seasons and were influenced significantly by vegetation, HRT, and water temperature. According to the mass balance approach, plant uptake removed 4.81–22.33% of P input, while media storage contributed 36.16–49.66%. Other P removal processes such as microbiota uptake removed around 0.26–4.13%. Media storage and plant uptake were identified as the main P removal processes in surface CWs treating polluted river water. This illustrated the importance of selecting media and plants in CWs for future practical application.

Role of Plants in a Constructed Wetland: Current and New Perspectives

The role of plants in the treatment of effluents by constructed wetland (CW) systems is under debate. Here, we review ways in which plants can affect CW processes and suggest two novel functions for plants in CWs. The first is salt phytoremediation by halophytes. We have strong evidence that halophytic plants can reduce wastewater salinity by accumulating salts in their tissues. Our studies have shown that Bassia indica, a halophytic annual, is capable of salt phytoremediation, accumulating sodium to up to 10% of its dry weight. The second novel use of plants in CWs is as phytoindicators of water quality. We demonstrate that accumulation of H2O2, a marker for plant stress, is reduced in the in successive treatment stages, where water quality is improved. It is recommended that monitoring and management of CWs consider the potential of plants as phytoremediators and phytoindicators.

Study on the Effects of Wetland Plants on DO in Domestic Sewage

By adopting the constructed wetland system of surface flow, the purification effects of different residence time of wastewater, different constructed wetland plants and their synergistic effect are studied in DO disposal in living wastewater. The results show that the best plant combination in purifying DO is that of Phragmites communis and Typha oriental,followed by that of Phragmites communis, and that of Arundo donax and Typha oriental is lowest.

Sorption of trace organics and engineered nanomaterials onto wetland plant material

Wastewater treatment plant (WWTP) effluents are sources for emerging pollutants, including organic compounds and engineered nanomaterials (ENMs), which then flow into aquatic systems. In this article, natural attenuation of pollutants by constructed wetland plants was investigated using lab-scale microcosm and batch sorption studies. The microcosms were operated at varying hydraulic residence times (HRTs) and contained decaying plant materials. Representative organic compounds and ENMs were simultaneously spiked into the microcosm influent, along with a conservative tracer (bromide), and then monitored in the effluent over time. It was observed that a more hydrophobic compound-natural estrogen achieved better removal than a polar organic compound – para-chlorobenzoic acid (pCBA), which mimics the behaviour of the tracer. Batch sorption experiments showed that estrogen has higher sorption affinity than pCBA, highlighting the importance of sorption to the plant materials as a removal process for the organic contaminants in the microcosms. Wetland plants were also found a potential sorbent for ENMs. Two different ENMs (nano-silver and aqueous fullerenes) were included in this study, both of which experienced comparable removal in the microcosms. Relative to the tracer, the highest removal of ENMs and trace organics was 60% and 70%, respectively. A more than two-fold increase in HRT increased the removal efficiency of the contaminants in the range of 20–60%. The outcome of this study supports that plant materials of wetlands can play an important role in removing emerging pollutants from WWTP effluent.

Allium Chromosome Aberration Test for Evaluation Effect of Cleaning Municipal Water with Constructed Wetland (CW) in Sveti Tomaž, Slovenia

® ; Allium metaphase test; Chromosome damage Abstract We show the effectiveness of the communal waste water cleaning plant of the type LIMNOWET ® Constructed Wetlands (CW). The tests were done with the Allium metaphase test and show the degree of genotoxicity, by observing the aberrations of the metaphasic chromosomes of the plant Allium cepa L. that are evoked by genotoxic substances in the polluted water. The CW plant reduced the degree of genotoxicity 29.0% to 3.5% (the Fisher's Exact test: p=9.2e-13<0,00001). Therefore CW is a very effective ecoremediation technique, since it removes up to 96% of waste.

Study on the Effects of Wastewater Duress on MDA in Constructed Wetland Plants

The study on the wetland plant species and their resistance is the key to ecological wastewater treatment technology. The study on the effects of wastewater duress on the physical and chemical properties of constructed wetland plants and the anti-stress capability of constructed wetland plants can provide theoretical basis and technical support for constructed wetland plant material selection. By adopting surface flow constructed wetland system, the effects are studied on MDA in 4 common plants in Shandong (Phragmites communis, Typha oriental, Arundo donax and Canna generalis) in different wastewater duress time. The results show: All in all, Phragmites communis and Canna generalis have stronger anti-stress capability, while Arundo donax and Typha oriental has weaker anti-stress capability; but as wastewater duress time increases, the anti-stress capability of Phragmites communis decreases, while the anti-stress capability of Canna generalis increases.