Sample records for hybrid constructed wetland

  1. Hybrid constructed wetlands for wastewater treatment: a worldwide review

    National Research Council Canada - National Science Library

    Sayadi, M.H; Kargar, R; Doosti, M.R; Salehi, H


    .... This study aimed to assess the potentiality of hybrid constructed wetlands for treating of landfill leachate, river polluted water, domestic, industrial, hospital, runoff and agricultural wastewater...

  2. Constructed Wetlands (United States)

    these systems can improve water quality, engineers and scientists construct systems that replicate the functions of natural wetlands. Constructed wetlands are treatment systems that use natural processes

  3. Removal of Nutrients from Septic Effluent with Re-circulated Hybrid Tidal Flow Constructed Wetland (United States)

    Lihua Cui; Jigkun Feng; Ying Ouyang; Peiwen. Deng


    Hybrid tidal flow constructed wetland (CW) with recirculation is an improved biological and engineering technique for removal of excess nutrients and certain pollutants from wastewater. This study investigated the removal efficiency of total phosphorus (TP), ammonia-nitrogen (NH3-N), and total nitrogen (TN) from septic tank effluent with the hybrid tidal flow CW system...

  4. Study on treatment of aquaculture wastewater using a hybrid constructed wetland (United States)

    Hu, Jinzhao; Hu, Rui; Qi, Dan; Lu, Xujie


    This paper reported the pollutant removal performances of a hybrid wetland system for the treatment of aquaculture wastewater. The system consisted of two treatment stages: a subsurface vertical flow (VF) wetland, followed by a horizontal flow (HF). The aquaculture wastewater with the different concentrations such as eutrophy and mesotrophy was treated using hybrid constructed wetland. The experimental results showed that the removal efficiencies of eutrophy aquaculture wastewater achieved 56%, 71%, 73% for nitrite, phosphate and nitrate, respectively. At the same conditions, it can be found that the removal efficiencies of mesotrophy aquaculture wastewater achieved 39%, 74%, 73% for nitrite, phosphate and nitrate, respectively.

  5. Effectiveness of pollutants removal in hybrid constructed wetlands – different configurations case study

    Directory of Open Access Journals (Sweden)

    Gajewska Magdalena


    Full Text Available In recent years, an increase in interest in hybrid constructed wetland systems (HCWs has been observed. The aim of the paper is to compare different HCW configurations in terms of mass removal rates and efficiency of pollutants removal. Analysed data have been collected at multistage constructed wetlands in Poland, which are composed by at least two beds: horizontal subsurface flow (SSHF and vertical subsurface flow (SSVF. The evaluation was focused on hybrid constructed wetlands performance with HF+VF vs. VF+HF configuration, where influent wastewater of the same composition was treated. In analysed HCWs, the effective removal of organic matter from 75.2 to 91.6% COD was confirmed. Efficiency of total nitrogen removal varied from 47.3 to 91.7%. The most effective removal of TN (8.3 g m−2 d−1 occurred in the system with VF+VF+HF configuration.

  6. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.


    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy

  7. Reduction of Contaminants (Physical, Chemical, and Microbial) in Domestic Wastewater through Hybrid Constructed Wetland


    Sehar, Shama; Aamir, Rabia; Naz, Iffat; Ali, Naeem; Ahmed, Safia


    The current research was focused mainly on the designing and construction of efficient laboratory scale hybrid constructed wetland (HCW) for the treatment of domestic wastewater. Parameters like COD, BOD5, PO4, SO4, NO3, NO2, and pathogenic indicator microbes were monitored after hydraulic retention time (HRT) of 4, 8, 12, 16, and 20 days. Treatment efficiency of HCW kept on increasing with the increase in hydraulic retention time. Maximum efficiency of HCW was observed with a 20-day HRT, tha...

  8. Seasonal Variation of Nutrient Removal in a Full-Scale Artificial Aerated Hybrid Constructed Wetland

    Directory of Open Access Journals (Sweden)

    Jun Zhai


    Full Text Available To improve nutrient removal, a full-scale hybrid constructed wetland (CW consisting of pre-treatment units, vertical-baffled flow wetlands (VBFWs, and horizontal subsurface flow wetlands (HSFWs was installed in August 2014 to treat sewage wastewater. Artificial aeration (AA was applied continuously in the VBFW stage to improve the aerobic condition in the hybrid CW. Water samples were collected and analyzed twice a month between the period of August 2015 and July 2016. The results suggest that this new hybrid CW can achieve a satisfactory reduction of chemical oxygen demand (COD, ammonium nitrogen (NH4+-N, total nitrogen (TN, and total phosphorus (TP with average removal rates of 85% ± 10% (35% ± 19 g/m2 per day, 76% ± 18% (7% ± 2 g/m2 per day, 65% ± 13% (8% ± 2 g/m2 per day, and 65% ± 21% (1 g/m2 per day, respectively. AA significantly improved the aerobic condition throughout the experimental period, and the positive influence of AA on nitrogen removal was found to be higher during summer that during winter. A significant positive correlation between water temperature and nutrient removal (p < 0.01 was observed in the system. Overall, this study demonstrates the application of AA in a full-scale hybrid CW with satisfactory nutrient removal rates. The hybrid CW system with artificial aeration can serve as a reference for future applications areas where land availability is limited.

  9. Constructed Wetlands for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Jan Vymazal


    Full Text Available The first experiments using wetland macrophytes for wastewater treatment were carried out in Germany in the early 1950s. Since then, the constructed wetlands have evolved into a reliable wastewater treatment technology for various types of wastewater. The classification of constructed wetlands is based on: the vegetation type (emergent, submerged, floating leaved, free-floating; hydrology (free water surface and subsurface flow; and subsurface flow wetlands can be further classified according to the flow direction (vertical or horizontal. In order to achieve better treatment performance, namely for nitrogen, various types of constructed wetlands could be combined into hybrid systems.

  10. Treatment of tannery wastewater in a pilot-scale hybrid constructed wetland system in Bangladesh. (United States)

    Saeed, Tanveer; Afrin, Rumana; Muyeed, Abdullah Al; Sun, Guangzhi


    This paper reports the pollutant removal performances of a hybrid wetland system in Bangladesh for the treatment of a tannery wastewater. The system consisted of three treatment stages: a subsurface vertical flow (VF) wetland, followed by a horizontal flow (HF) and a VF wetland. The wetlands were planted with common reed (Phragmites australis), but employed different media, including organic coco-peat, cupola slag and pea gravel. In the first stage, experimental results demonstrated significant removal of ammonia (52%), nitrate (54%), BOD (78%), and COD (56%) under high organics loading rate (690 g COD m(-2)d(-1)); simultaneous nitrification, denitrification, and organics degradation were attributed to the unique characteristics of the coco-peat media, which allowed greater atmospheric oxygen transfer for nitrification and organic degradation, and supply of organic carbon for denitrification. The second stage HF wetland produced an average PO(4) removal of 61%, primarily due to adsorption by the iron-rich cupola slag media. In the third treatment stage, which was filled with gravel media, further BOD removal (78%) from the tannery wastewater depleted organic carbon, causing the accumulation of NO(3) in the wastewater. Overall, the average percentage removals of NH(3)-N, NO(3)-N, BOD, COD, and PO(4) were 86%, 50%, 98%, 98% and 87%, respectively, across the whole hybrid system. The results provided a strong evidence to support widespread research and application of the constructed wetland as a low-cost, energy-efficient, wastewater treatment technology in Bangladesh. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Phytoremediation of domestic wastewater using a hybrid constructed wetlands in mountainous rural area. (United States)

    Elfanssi, Saloua; Ouazzani, Naaila; Latrach, Lahbib; Hejjaj, Abdessamed; Mandi, Laila


    The purpose of this study is to evaluate the efficiency of a hybrid constructed wetlands (HCW) in a rural mountainous area. The experiment was set up in small rural community named Tidili within the region of Marrakech-Morocco. The wastewater treatment plant was composed of three vertical flow constructed wetlands (VFCWs) working in parallel, followed by two parallel horizontal-subsurface flow constructed wetlands (HFCWs), with hydraulic loading rate of 0.5 m3/ m2.d and 0.75 m3/m2.d, respectively. The two units were planted with Phragmites australis at a density of 4 plants / m2. Wastewater samples were collected at the inlet of the storage tank and at the outlet of the whole system (VFCWs, HFCWs) stages. The main removal percentages of TSS, BOD5, COD, TN and TP were respectively 95, 93, 91, 67 and 62%. The system showed very high capacity to remove total coliforms, fecal coliforms and fecal streptococci (4.46, 4.31 and 4.10 Log units respectively). Artificial neural networks (ANNs) were used to model the quality parameters (TSS, BOD5, COD) and coliforms (TC, FS). Based on the obtained results, ANN model could be considered as an efficient tool to predict the studied phytoremediation performances using HCWs.

  12. Effects of the substrate depth on purification performance of a hybrid constructed wetland treating domestic sewage. (United States)

    Ren, Yong-Xiang; Zhang, Hai; Wang, Chao; Yang, Yong-Zhe; Qin, Zhen; Ma, Yun


    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.

  13. The use of hybrid constructed wetlands for wastewater treatment with special attention to nitrogen removal: a review of a recent development. (United States)

    Vymazal, Jan


    The hybrid systems were developed in the 1960s but their use increased only during the late 1990 s and in the 2000s mostly because of more stringent discharge limits for nitrogen and also more complex wastewaters treated in constructed wetlands (CWs). The early hybrid CWs consisted of several stages of vertical flow (VF) followed by several stages of horizontal flow (HF) beds. During the 1990 s, HF-VF and VF-HF hybrid systems were introduced. However, to achieve higher removal of total nitrogen or to treat more complex industrial and agricultural wastewaters other types of hybrid constructed wetlands including free water surface (FWS) CWs and multistage CWs have recently been used as well. The survey of 60 hybrid constructed wetlands from 24 countries reported after 2003 revealed that hybrid constructed wetlands are primarily used on Europe and in Asia while in other continents their use is limited. The most commonly used hybrid system is a VF-HF constructed wetland which has been used for treatment of both sewage and industrial wastewaters. On the other hand, the use of a HF-VF system has been reported only for treatment of municipal sewage. Out of 60 surveyed hybrid systems, 38 have been designed to treat municipal sewage while 22 hybrid systems were designed to treat various industrial and agricultural wastewaters. The more detailed analysis revealed that VF-HF hybrid constructed wetlands are slightly more efficient in ammonia removal than hybrid systems with FWS CWs, HF-VF systems or multistage VF and HF hybrid CWs. All types of hybrid CWs are comparable with single VF CWs in terms of NH4-N removal rates. On the other hand, CWs with FWS units remove substantially more total nitrogen as compared to other types of hybrid constructed wetlands. However, all types of hybrid constructed wetlands are more efficient in total nitrogen removal than single HF or VF constructed wetlands. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. The removal efficiency of constructed wetlands filled with the zeolite-slag hybrid substrate for the rural landfill leachate treatment. (United States)

    He, Hailing; Duan, Zhiwei; Wang, Zhenqing; Yue, Bo


    The removal efficiencies of two horizontal subsurface flow constructed wetlands (HSSF CWs, down-flow (F1) and up-flow (F2)) filled with the zeolite-slag hybrid substrate for the rural landfill leachate treatment were investigated. The adsorption experiment was conducted to evaluate the potential of zeolite and slag as the wetland substrate. The effects of distance variations along the longitudinal profile of wetland bed on pollutant removal were assessed by sampling at four locations (inlet, outlet, 0.55 m, and 1.10 m from the inlet). During the operation time, the influent and effluent concentrations of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen (TN), heavy metals, and polycyclic aromatic hydrocarbon (PAH) were measured. The results showed that the constructed wetlands were capable of removing COD, 20.5-48.2% (F1) and 18.6-61.2% (F2); NH3-N, 84.0-99.9% (F1) and 93.5-99.2% (F2); TN, 80.3-92.1% (F1) and 80.3-91.2% (F2); and heavy metals, about 90% (F1 and F2). The zeolite-slag hybrid substrate performed excellent removal efficiency for the nitrogen and heavy metals. The inlet area was the most active region of leachate removal. The up-flow constructed wetland (F2) has a higher removal efficiency for the PAH compounds. The significant removal efficiency illustrated that the rural landfill leachate can be treated using the horizontal subsurface flow constructed wetland filled with the zeolite-slag hybrid substrate.

  15. Reduction of Contaminants (Physical, Chemical, and Microbial) in Domestic Wastewater through Hybrid Constructed Wetland. (United States)

    Sehar, Shama; Aamir, Rabia; Naz, Iffat; Ali, Naeem; Ahmed, Safia


    The current research was focused mainly on the designing and construction of efficient laboratory scale hybrid constructed wetland (HCW) for the treatment of domestic wastewater. Parameters like COD, BOD5, PO4, SO4, NO3, NO2, and pathogenic indicator microbes were monitored after hydraulic retention time (HRT) of 4, 8, 12, 16, and 20 days. Treatment efficiency of HCW kept on increasing with the increase in hydraulic retention time. Maximum efficiency of HCW was observed with a 20-day HRT, that is, 97.55, 97.5, 89.35, 80.75, 96.04, 91.52, and 98.6% reduction from the zero time value for COD, BOD5, PO4, SO4, NO3, NO2, and fecal coliforms, respectively. After 20 days' time, the treated water was free of almost all nutrients and microbial pollutants. Hence, increasing hydraulic retention time was found to ameliorate the operational competence of HCW. Thus HCW can serve as a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries.

  16. Reduction of Contaminants (Physical, Chemical, and Microbial) in Domestic Wastewater through Hybrid Constructed Wetland (United States)

    Sehar, Shama; Aamir, Rabia; Naz, Iffat; Ali, Naeem; Ahmed, Safia


    The current research was focused mainly on the designing and construction of efficient laboratory scale hybrid constructed wetland (HCW) for the treatment of domestic wastewater. Parameters like COD, BOD5, PO4, SO4, NO3, NO2, and pathogenic indicator microbes were monitored after hydraulic retention time (HRT) of 4, 8, 12, 16, and 20 days. Treatment efficiency of HCW kept on increasing with the increase in hydraulic retention time. Maximum efficiency of HCW was observed with a 20-day HRT, that is, 97.55, 97.5, 89.35, 80.75, 96.04, 91.52, and 98.6% reduction from the zero time value for COD, BOD5, PO4, SO4, NO3, NO2, and fecal coliforms, respectively. After 20 days' time, the treated water was free of almost all nutrients and microbial pollutants. Hence, increasing hydraulic retention time was found to ameliorate the operational competence of HCW. Thus HCW can serve as a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries. PMID:23724336

  17. Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization (FISH). (United States)

    Yan, Li; Inamori, Ryuhei; Gui, Ping; Xu, Kai-qin; Kong, Hai-nan; Matsumura, Masatoshi; Inamori, Yuhei


    A molecular biology method, fluorescent in situ hybridization (FISH), in which the pre-treatment was improved in allusion to the media of the constructed wetlands (CW), e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria (AOB) quantity and the relation with oxidation-reduction potential (ORP) in the Typha latifolia constructed wetlands under three different loadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.

  18. Effluent quality and reuse potential of domestic wastewater treated in a pilot-scale hybrid constructed wetland system. (United States)

    Ayaz, Selma Ç; Aktaş, Özgür; Akça, Lütfi; Fındık, Nur


    The study investigates treatment and reuse potential of domestic wastewater of a small community of about 30 people sequentially by anaerobic pretreatment followed by horizontal (HSSF-CW) and vertical (VSSF-CW) sub-surface flow constructed wetlands operated in series. The organic and suspended solids load to the hybrid wetland system was decreased by anaerobic pretreatment. HSSF-CW mainly removed organic matter and supported denitrification whereas VSSF-CW mainly obtained nitrification and phosphorus removal. Recirculation of the effluent increased particularly total nitrogen removal in the wetland system. The study involves evaluation of the whole system in terms of effluent quality. It was achieved on average >95% organic matter and >90% nitrogen removal in the hybrid constructed wetland system with anaerobic pretreatment at a specific wetland surface area of only about 1 m(2) per person. Average mass removal rates were 21.17 gCOD/m(2)day, 5.58 gBOD5/m(2)day, 2.78 gTKN/m(2)day, 1.35 gTN/m(2)day, 0.44 gTP/m(2)day and 5.21 gTSS/m(2)day throughout the total duration of the operation. Consequently, the effluent met the regulations for discharge limits for organic matter and suspended solids. COD and TN concentrations decreased to below 20 mg/L in the effluent. It was also shown that effluent of the system could be reused for irrigation if it is disinfected properly. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Performance and microbial community in hybrid Anaerobic Baffled Reactor-constructed wetland for nitrobenzene wastewater. (United States)

    Lin, Yingzi; Yin, Jun; Wang, Jianhui; Tian, Wende


    A process combining an Anaerobic Baffled Reactor (ABR) and a constructed wetland was employed to treat nitrobenzene wastewater. The overall performance was examined throughout long-term operation with a hydraulic retention time (HRT) of 24 h at 30±1 °C. The effluent nitrobenzene concentration of the ABR and constructed wetland was less than 4.81 and 1.94 mg/L, respectively, with an initial nitrobenzene concentration of 80 mg/L at the steady-state periods. The corresponding removal efficiencies were 97.02% and 73.93%, respectively. Moreover, 97.29% of aniline produced in the ABR could be removed in the subsequent wetland. The number of sequenced clones from each library was sufficient to cover archaea and eubacteria diversity at the species level and to obtain a representation of the total microbial diversity in the ABR. The predominant microbial populations in the ABR were identified as Pseudomonas putida, Methanosaeta concilii and Methanothrix soehngenii. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  20. Performance of hybrid vertical up- and downflow subsurface flow constructed wetlands in treating synthetic high-strength wastewater. (United States)

    Zhao, Yong-Jun; Cheng, Pu; Pei, Xi; Zhang, Hui; Yan, Cheng; Wang, Shou-Bing


    The performance and temporal variation of hybrid vertical-subsurface flow constructed wetlands (VFCWs) in response to two-stage combinations of vertical upflow (VUF) and vertical downflow (VDF) were analyzed in this research. The results of high carbon (C) treatment and high nitrogen (N) treatment were similar. The Lythrum salicaria treatment showed higher removal efficiency than CWs planted with Acorus calamus. Under high C- and N-loading treatments, the optimum two-stage combination was VDF-VUF VFCWs planted with A. calamus. Furthermore, the highest nutrient removal efficiencies were achieved in late summer (July and August) and early autumn (September). The chemical oxygen demand and total nitrogen removal efficiencies were significantly affected (P wetland plant.

  1. Optimization of operating parameters of hybrid vertical down-flow constructed wetland systems for domestic sewerage treatment. (United States)

    Huang, Zhujian; Zhang, Xianning; Cui, Lihua; Yu, Guangwei


    In this work, three hybrid vertical down-flow constructed wetland (HVDF-CW) systems with different compound substrates were fed with domestic sewage and their pollutants removal performance under different hydraulic loading and step-feeding ratio was investigated. The results showed that the hydraulic loading and step-feeding ratio were two crucial factors determining the removal efficiency of most pollutants, while substrate types only significantly affected the removal of COD and NH4(+)-N. Generally, the lower the hydraulic loading, the better removal efficiency of all contaminants, except for TN. By contrast, the increase of step-feeding ratio would slightly reduce the removal rate of ammonium and TP but obviously promoted the TN removal. Therefore, the optimal operation of this CWs could be achieved with low hydraulic loading combined with 50% of step-feeding ratio when TN removal is the priority, whereas medium or low hydraulic loading without step-feeding would be suitable when TN removal is not taken into consideration. The obtained results in this study can provide us with a guideline for design and optimization of hybrid vertical flow constructed wetland systems to improve the pollutants removal from domestic sewage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage. (United States)

    Xiao, Haiwen; Zhang, Shengli; Zhai, Jun; He, Qiang; Mels, Adriaan; Ning, Kejia; Liu, Jie


    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy metal concentrations in water, sediments, and plant tissues in the hybrid CW were analysed. The removal of heavy metals from the water stream in the monitoring period was not statistically significant. Metal concentrations in the sediments generally decreased along the wastewater treatment process. The reductive anaerobic condition in the VBFW may promote the sulphate reduction and form highly insoluble Cu, Pb, and Zn sulphides, resulting in the higher concentration of the bivalent cations in the VBFW sediments than the corresponding values in the HSSF; however, the aerobic and anoxic environments in the HSSF enhanced the removal of Cr with the co-precipitation of iron and manganese oxides, and their hydroxides. Metal concentrations in plant tissues were not significantly influenced by the concentrations in sediments, while roots contained statistically higher metal concentrations than stems and leaves. The sediments stored 94.01, 86.31, 95.85, and 89.51% of the total Cu, Pb, Cr, and Zn retained in the hybrid CW system, respectively, while only small fractions (<10%) were accumulated in the harvestable macrophyte tissues. It is important to clean not only the accessible sediments in free water surface tank and ponds but also the embedded sediments in vegetated beds for the sustainable removal of heavy metals.

  3. Evaluation of two hybrid poplar clones as constructed wetland plant species for treating saline water high in boron and selenium, or waters only high in boron (United States)

    Wetland mesocosms were constructed to assess two salt- and B-tolerant hybrid poplar clones (Populus trichocarpa ×P. deltoides×P. nigra '345-1' and '347-14') for treating saline water high in boron (B) and selenium (Se). In addition, a hydroponic experiment was performed to test the B tolerance and B...

  4. Constructed Wetlands for Wastewater Treatment


    Jan Vymazal


    The first experiments using wetland macrophytes for wastewater treatment were carried out in Germany in the early 1950s. Since then, the constructed wetlands have evolved into a reliable wastewater treatment technology for various types of wastewater. The classification of constructed wetlands is based on: the vegetation type (emergent, submerged, floating leaved, free-floating); hydrology (free water surface and subsurface flow); and subsurface flow wetlands can be further classified accordi...

  5. The Influence of the Ratio of Nitrate to Ammonium Nitrogen on Nitrogen Removal in the Economical Growth of Vegetation in Hybrid Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Haq Nawaz Abbasi


    Full Text Available Growing vegetables economically in the use of constructed wetland for wastewater treatment can play a role in overcoming water and food scarcity. Allium porrum L., Solanum melongena L., Ipomoea aquatica Forsk., and Capsicum annuum L. plants were selected to grow in hybrid constructed wetland (CW under natural conditions. The impact of the ratio of nitrate to ammonium nitrogen on ammonium and nitrate nitrogen removal and on total nitrogen were studied in wastewater. Constructed wetland planted with Ipomoea aquatica Forsk. and Solanum melongena L. showed higher removal efficiency for ammonium nitrogen under higher ammonium concentration, whereas Allium porrum L.-planted CW showed higher nitrate nitrogen removal when NO3–N concentration was high in wastewater. Capsicum annuum L.-planted CW showed little efficiency for both nitrogen sources compared to other vegetables.

  6. Multi-stage hybrid subsurface flow constructed wetlands for treating piggery and dairy wastewater in cold climate. (United States)

    Zhang, Xiaomeng; Inoue, Takashi; Kato, Kunihiko; Izumoto, Hayato; Harada, June; Wu, Da; Sakuragi, Hiroaki; Ietsugu, Hidehiro; Sugawara, Yasuhide


    This study followed three field-scale hybrid subsurface flow constructed wetland (CW) systems constructed in Hokkaido, northern Japan: piggery O (2009), dairy G (2011), and dairy S (2006). Treatment performance was monitored from the outset of operation for each CW. The ranges of overall purification efficiency for these systems were 70-86%, 40-85%, 71-90%, 91-96%, 94-98%, 84-97%, and 70-97% for total N (TN), NH4-N, total P, chemical oxygen demand (COD), biochemical oxygen demand, suspended solid, and total Coliform, respectively. The hybrid system's removal rates were highest when influent loads were high. COD removal rates were 46.4 ± 49.2, 94.1 ± 36.6, and 25.1 ± 15.5 g COD m-2 d-1 in piggery O, dairy G, and dairy S, with average influent loads of 50.5 ± 51.5, 98.9 ± 37.1, and 26.9 ± 16.0 g COD m-2 d-1, respectively. The systems had overall COD removal efficiencies of around 90%. TN removal efficiencies were 62 ± 19%, 82 ± 9%, and 82 ± 15% in piggery O, dairy G, and dairy S, respectively. NH4-N removal efficiency was adversely affected by the COD/TN ratio. Results from this study prove that these treatment systems have sustained and positive pollutant removal efficiencies, which were achieved even under extremely cold climate conditions and many years after initial construction.

  7. Influence of hydraulic loading rate, simulated storm events and seasonality on the treatment performance of an experimental three-stage hybrid constructed wetland system


    Ávila Martín, Cristina; García Serrano, Joan; Garfi, Marianna


    An experimental hybrid system based on an anaerobic reactor followed by three stages of different constructed wetland configurations was evaluated when operating under a high hydraulic loading rate (HLR = 0.27 m d-1, considering the area of the VF beds) for one year, which corresponds to four times the nominal hydraulic loading rate, with the purpose of reducing the specific area required. Moreover, in order to assess its buffer capacity, a major storm event was simulated by increasing the HL...

  8. The effect of aeration and recirculation on a sand-based hybrid constructed wetland treating low-strength domestic wastewater. (United States)

    Zapater-Pereyra, M; Kyomukama, E; Namakula, V; van Bruggen, J J A; Lens, P N L


    The Duplex-constructed wetland (CW) is a hybrid system composed of a vertical flow (VF) CW on top of a horizontal flow filter (HFF). Each compartment is designed to play a different role: aerobic treatment in the VF CW due to intermittent feeding and anoxic treatment in the HFF due to saturated conditions. Three Duplex-CWs were used in this study: Control, Aerated and Recirculating. The role of each compartment was tested for pollutant removal and micro-invertebrate abundance. In all systems, the VF CW removed mainly organic matter, solids and NH4(+)-N. Pathogens were removed in both compartments. Likewise, total nitrogen removal occurred in both compartments, only the Recirculating HFF was not able to denitrify the nitrogen due to the slightly more oxic conditions as compared to the other systems. All systems met discharge guidelines for organic matter, but only the Control and Aerated systems met those for total nitrogen. At the applied loading rates, the pollutant removal was not significantly enhanced by the use of aeration and recirculation. Therefore, operation as in the Control system, without aeration or recirculation, is recommended for the tested Duplex-CWs. If artificial aeration will be used in CWs, the support material should be carefully selected to allow a proper air distribution.

  9. Constructed Wetlands for Wastewater Treatment (United States)

    This presentation is a general introductory overview of constructed wetlands for wastewater treatment. Photographs show a wide range of applications and sizes. Summary data on cost and performance from previously published documents by WERF and EPA is presented. Previously pre...

  10. Performance of three pilot-scale hybrid constructed wetlands for total coliforms and Escherichia coli removal from primary effluent - a 2-year study in a subtropical climate. (United States)

    Zurita, Florentina; Carreón-Álvarez, Alejandra


    Three pilot-scale two-stage hybrid constructed wetlands were evaluated in order to compare their efficiency for total coliforms (TCol) and Escherichia coli removal and to analyze their performances in two 1-year periods of experimentation. System I consisted of a horizontal flow (HF) constructed wetland (CW) followed by a stabilization pond. System II was also configured with a HF CW as a first stage which was then followed by a vertical flow (VF) CW as a second stage. System III was configured with a VF CW followed by a HF CW. In the first year of evaluation, the HF-VF system was the most effective for TCol removal (p < 0.05) and achieved a reduction of 2.2 log units. With regard to E. coli removal, the HF-VF and VF-HF systems were the most effective (p < 0.05) with average reductions of 3.2 and 3.8 log units, respectively. In the second year, the most effective were those with a VF component for both TCol and E. coli which underwent average reductions of 2.34-2.44 and 3.44-3.74 log units, respectively. The reduction achieved in E. coli densities, in both years, satisfy the World Health Organization guidelines that require a 3-4 log unit pathogen reduction in wastewater treatment systems.

  11. Environmental footprint of constructed wetlands treating wastewater. (United States)

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


    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.

  12. Hybrid system up-flow constructed wetland integrated with microbial fuel cell for simultaneous wastewater treatment and electricity generation. (United States)

    Oon, Yoong-Ling; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Oon, Yoong-Sin; Lehl, Harvinder Kaur; Thung, Wei-Eng


    An innovative design of upflow constructed wetland-microbial fuel cell (UFCW-MFC) planted with cattail was used for simultaneous wastewater treatment and electricity generation. The electrodes material employed in the study was carbon felt. The main aim of this study is to assess the performance of the UFCW coupling with MFC in term of ability to treat wastewater and the capability to generate bioelectricity. The oxidation reduction potential (ORP) and dissolved oxygen (DO) profile showed that the anaerobic and aerobic regions were well developed in the lower and upper bed, respectively, of UFCW-MFC. Biodegradation of organic matter, nitrification and denitrification was investigated and the removal efficiencies of COD, NO3(-), NH4(+) were 100%, 40%, and 91%, respectively. The maximum power density of 6.12 mW m(-2) and coulombic efficiency of 8.6% were achieved at electrode spacing of anode 1 (A1) and cathode (15 cm). Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Long-term nitrogen compound removal trends of a hybrid subsurface constructed wetland treating milking parlor wastewater throughout its 7 years of operation. (United States)

    Harada, J; Inoue, T; Kato, K; Izumoto, H; Zhang, X; Sakuragi, H; Wu, D; Ietsugu, H; Sugawara, Y


    This study evaluated the nitrogen compound removal efficiency of a hybrid subsurface constructed wetland, which began treating milking parlor wastewater in Hokkaido, northern Japan, in 2006. The wetland's overall removal rates of total nitrogen (TN) and ammonium (NH4(+)-N) improved after the second year of operation, and its rate of organic nitrogen (Org-N) removal was stable at 90% efficiency. Only nitrate (NO3(-)-N) levels were increased following the treatment. Despite increased NO3(-)-N (maximum of 3 mg-N/L) levels, TN removal rates were only slightly affected. Removal rates of TN and Org-N were highest in the first vertical bed. NH4(+)-N removal rates were highest in the second vertical bed, presumably due to water recirculation and pH adjustment. Concentrations of NO3(-)-N appeared when total carbon (TC) levels were low, which suggests that low TC prevented complete denitrification in the second vertical bed and the final horizontal bed. In practice, the beds removed more nitrogen than the amount theoretically removed by denitrification, as calculated by the amount of carbon removed from the system. This carbon-nitrogen imbalance may be due to other nitrogen transformation mechanisms, which require less carbon.

  14. Hybrid constructed wetlands for highly polluted river water treatment and comparison of surface- and subsurface-flow cells. (United States)

    Zheng, Yucong; Wang, Xiaochang; Xiong, Jiaqing; Liu, Yongjun; Zhao, Yaqian


    A series of large pilot constructed wetland (CW) systems were constructed near the confluence of an urban stream to a larger river in Xi'an, a northwestern megacity in China, for treating polluted stream water before it entered the receiving water body. Each CW system is a combination of surface-and subsurface-flow cells with local gravel, sand or slag as substrates and Phragmites australis and Typha orientalis as plants. During a one-year operation with an average surface loading of 0.053 m(3)/(m(2)·day), the overall COD, BOD, NH3-N, total nitrogen (TN) and total phosphorus (TP) removals were 72.7% ± 4.5%, 93.4% ± 2.1%, 54.0% ± 6.3%, 53.9% ± 6.0% and 69.4% ± 4.6%, respectively, which brought about an effective improvement of the river water quality. Surface-flow cells showed better NH3-N removal than their TN removal while subsurface-flow cells showed better TN removal than their NH3-N removal. Using local slag as the substrate, the organic and phosphorus removal could be much improved. Seasonal variation was also found in the removal of all the pollutants and autumn seemed to be the best season for pollutant removal due to the moderate water temperature and well grown plants in the CWs. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  15. Storm event-scale nutrient attenuation in constructed wetlands experiencing a Mediterranean climate: A comparison of a surface flow and hybrid surface-subsurface flow system. (United States)

    Adyel, Tanveer M; Oldham, Carolyn E; Hipsey, Matthew R


    Among different Water Sensitive Urban Design options, constructed wetlands (CWs) are used to protect and restore downstream water quality by attenuating nutrients generated by stormwater runoff. This research compared the nutrient attenuation ability during a diverse population of storm events of two CWs: (a) a hybrid CW with multiple alternating surface flow (SF) and laterite-based subsurface flow (SSF) compartments, and (b) a single stage SF CW. Within-storm variability, nutrient concentrations were assessed at 2 to 3-h intervals at both the main inlet and outlet of each CW. Dissolved oxygen concentrations of the surface waters were also monitored at 10-min intervals using high frequency in situ sensors. Nutrient loads into the CWs were observed to be higher when a high rainfall event occurred, particularly after longer antecedent dry conditions. Longer hydraulic retention times promoted higher attenuation at both sites. However, the relative extent of nutrient attenuation differed between the CW types; the mean total nitrogen (TN) attenuation in the hybrid and SF CW was 45 and 48%, respectively. The hybrid CW attenuated 67% total phosphorus (TP) loads on average, while the SF CW acted as a net TP source. Periodic storm events transitioned the lentic CW into a lotic CW and caused riparian zone saturation; it was therefore hypothesized that such saturation of organic matter rich-riparian zones led to release of TP in the system. The hybrid CW attenuated the released TP in the downstream laterite-based SSF compartments. Diel oxygen metabolism calculated before and after the storm events was found to be strongly correlated with water temperature, solar exposure and antecedent dry condition during the pre-storm conditions. Furthermore, the SF CW showed a significant relationship between overall nutrient load attenuation and the change in oxygen metabolism during the storm perturbation, suggesting oxygen variation could be a useful proxy indicator of CW function

  16. Performance of a pilot demonstration-scale hybrid constructed wetland system for on-site treatment of polluted urban river water in Northwestern China. (United States)

    Zheng, Yucong; Wang, Xiaochang C; Dzakpasu, Mawuli; Ge, Yuan; Zhao, Yaqian; Xiong, Jiaqing


    Hybrid constructed wetland (HCW) systems have been used to treat various wastewaters across the world. However, large-scale applications of HCWs are scarce, particularly for on-site improvement of the water quality of highly polluted urban rivers in semi-arid regions. In this study, a large pilot-scale HCW system was constructed to improve the water quality of the Zaohe River in Xi'an, China. With a total area of about 8000 m(2), the pilot HCW system, composed of different configurations of surface and subsurface flow wetlands, was operated for 2 years at an average inflow volume rate of 362 m(3)/day. Local Phragmites australis and Typha orientalis from the riverbank were planted in the HCW system. Findings indicate a higher treatment efficiency for organics and suspended solids than nutrients. The inflow concentrations of 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (TN), NH3-N, and total phosphorus (TP) were 125.6, 350.9, 334.2, 38.5, 27.2, and 3.9 mg/L, respectively. Average removal efficiencies of 94.4, 74.5, 92.0, 56.3, 57.5, and 69.2%, respectively, were recorded. However, the pollutant removal rates were highly seasonal especially for nitrogen. Higher removals were recorded for all pollutants in the autumn while significantly lower removals were recorded in the winter. Plant uptake and assimilation accounted for circa 19-29 and 16-23% of the TN and TP removal, respectively. Moreover, P. australis demonstrated a higher nutrient uptake ability and competitive potential. Overall, the high efficiency of the pilot HCW for improving the water quality of such a highly polluted urban river provided practical evidence of the applicability of the HCW technology for protecting urban water environments.

  17. Removal Efficiency of Constructed Wetland for Treatment of Agricultural Wastewaters

    Directory of Open Access Journals (Sweden)

    Michal Šereš


    Full Text Available This study describes performance of a hybrid constructed wetland (CW for treating wastewater from small farm in Czech Republic. The CW consisting of two horizontal filters, one vertical filter and three shallow pondsand reduced inflow values of 25.400 mg/L COD and 2.640 mg/L BOD5 by up to 99%.

  18. Removal efficiency of constructed wetland for treatment of agricultural wastewaters

    Czech Academy of Sciences Publication Activity Database

    Šereš, M.; Hnátková, T.; Vymazal, J.; Vaněk, Tomáš


    Roč. 12, č. 1 (2017), s. 45-52 ISSN 1857-1727 R&D Projects: GA TA ČR TA01020573 Institutional support: RVO:61389030 Keywords : Agriculture wastewater * Constructed wetland * Horizontal filter * Hybrid systems * Vertical filter Subject RIV: DJ - Water Pollution ; Quality

  19. Design and development of two novel constructed wetlands: the duplex-constructed wetland and the constructed wetroof

    NARCIS (Netherlands)

    Zapater Pereyra, M.


    Maribel Zapater Pereyra Abstract thesis:  Design and development of two novel constructed wetlands: the Duplex-constructed wetland and the Constructed wetroof Constructed wetlands (CWs) are among the few natural treatment systems that can guarantee an efficient wastewater treatment and an

  20. Assessment of the technological reliability of a hybrid constructed wetland for wastewater treatment in a mountain eco-tourist farm in Poland. (United States)

    Jucherski, Andrzej; Nastawny, Maria; Walczowski, Andrzej; Jóźwiakowski, Krzysztof; Gajewska, Magdalena


    The aim of the present study was to assess the technological reliability of a domestic hybrid wastewater treatment installation consisting of a classic three-chambered (volume 6 m3) septic tank, a vertical flow trickling bed filled with granules of a calcinated clay material (KERAMZYT), a special wetland bed constructed on a slope, and a permeable pond used as a receiver. The test treatment plant was located at a mountain eco-tourist farm on the periphery of the spa municipality of Krynica-Zdrój, Poland. The plant's operational reliability in reducing the concentration of organic matter, measured as biochemical oxygen demand (BOD5) and chemical oxygen demand (COD), was 100% when modelled by both the Weibull and the lognormal distributions. The respective reliability values for total nitrogen removal were 76.8% and 77.0%, total suspended solids - 99.5% and 92.6%, and PO4-P - 98.2% and 95.2%, with the differences being negligible. The installation was characterized by a very high level of technological reliability when compared with other solutions of this type. The Weibull method employed for statistical evaluation of technological reliability can also be used for comparison purposes. From the ecological perspective, the facility presented in the study has proven to be an effective tool for protecting local aquifer areas.

  1. Enhancement of Nutrient Removal in a Hybrid Constructed Wetland Utilizing an Electric Fan Air Blower with Renewable Energy of Solar and Wind Power

    Directory of Open Access Journals (Sweden)

    Dong Jin Lee


    Full Text Available The sewage treatment efficiency of hybrid constructed wetlands (CWs was evaluated under different ventilation methods. The removal efficiencies of biochemical oxygen demand (BOD, total nitrogen (TN, and total phosphorus (TP in the vertical flow- (VF- horizontal flow (HF CWs using an electric fan air blower by the renewable energy of solar and wind power were higher than those by natural ventilation, excluding only suspended solids (SS. The TN treatment efficiency in the CW using the air blower especially increased rapidly by 16.6% in comparison with the CW employing natural ventilation, since the VF bed provided suitable conditions (aerobic for nitrification to occur. The average removal efficiencies of BOD, SS, TN, and TP in the effluent were 98.8, 97.4, 58.0, and 48.3% in the CW using an electric fan air blower, respectively. The treatment performance of the CWs under different ventilation methods was assessed, showing TN in the CW using an electric fan air blower to be reduced by 57.5~58.6% for inlet TN loading, whereas reduction by 19.0~53.3% was observed in the CW with natural ventilation. Therefore, to increase the removal of nutrients in CWs, an improved ventilation system, providing ventilation via an electric fan air blower with the renewable energy, is recommended.

  2. Constructed wetlands for wastewater treatment in cold climate - A review. (United States)

    Wang, Mo; Zhang, Dong Qing; Dong, Jian Wen; Tan, Soon Keat


    Constructed wetlands (CWs) have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option worldwide. However, the application of CW for wastewater treatment in frigid climate presents special challenges. Wetland treatment of wastewater relies largely on biological processes, and reliable treatment is often a function of climate conditions. To date, the rate of adoption of wetland technology for wastewater treatment in cold regions has been slow and there are relatively few published reports on CW applications in cold climate. This paper therefore highlights the practice and applications of treatment wetlands in cold climate. A comprehensive review of the effectiveness of contaminant removal in different wetland systems including: (1) free water surface (FWS) CWs; (2) subsurface flow (SSF) CWs; and (3) hybrid wetland systems, is presented. The emphasis of this review is also placed on the influence of cold weather conditions on the removal efficacies of different contaminants. The strategies of wetland design and operation for performance intensification, such as the presence of plant, operational mode, effluent recirculation, artificial aeration and in-series design, which are crucial to achieve the sustainable treatment performance in cold climate, are also discussed. This study is conducive to further research for the understanding of CW design and treatment performance in cold climate. Copyright © 2017. Published by Elsevier B.V.

  3. Constructed wetlands as biofuel production systems (United States)

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


    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.

  4. Effect of by-pass and effluent recirculation on nitrogen removal in hybrid constructed wetlands for domestic and industrial wastewater treatment. (United States)

    Torrijos, V; Gonzalo, O G; Trueba-Santiso, A; Ruiz, I; Soto, M


    Hybrid constructed wetlands (CWs) including subsurface horizontal flow (HF) and vertical flow (VF) steps look for effective nitrification and denitrification through the combination of anaerobic/anoxic and aerobic conditions. Several CW configurations including several configurations of single pass systems (HF + HF, VF + VF, VF + HF), the Bp(VF + HF) arrangement (with feeding by-pass) and the R(HF + VF) system (with effluent recirculation) were tested treating synthetic domestic wastewater. Two HF/VF area ratios (AR) were tested for the VF + HF and Bp(VF + HF) systems. In addition, a R(VF + VF) system was tested for the treatment of a high strength industrial wastewater. The percentage removal of TSS, COD and BOD5 was usually higher than 95% in all systems. The single pass systems showed TN removal below the threshold of 50% and low removal rates (0.6-1.2 g TN/m(2) d), except the VF + VF system which reached 63% and 3.5 g TN/m(2) d removal but only at high loading rates. Bp(VF + HF) systems required by-pass ratios of 40-50% and increased TN removal rates to approximately 50-60% in a sustainable manner. Removal rates depended on the AR value, increasing from 1.6 (AR 2.0) to 5.2 g TN/m(2) d (AR 0.5), both working with synthetic domestic wastewater. On real domestic wastewater the Bp (VF + HF) (AR 0.5 and 30% by-pass) reached 2.5 g TN/m(2) d removal rate. Effluent recirculation significantly improved the TN removal efficiency and rate. The R(HF + VF) system showed stable TN removals of approximately 80% at loading rates ranging from 2 to 8 g TN/m(2) d. High TN removal rates (up to 73% TN and 8.4 g TN/m(2) d) were also obtained for the R(VF + VF) system treating industrial wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Intensification of constructed wetlands for land area reduction: a review. (United States)

    Ilyas, Huma; Masih, Ilyas


    The large land area requirement of constructed wetlands (CWs) is a major limitation of its application especially in densely populated and mountainous areas. This review paper provides insights on different strategies applied for the reduction of land area including stack design and intensification of CWs with different aeration methods. The impacts of different aeration methods on the performance and land area reduction were extensively and critically evaluated for nine wetland systems under three aeration strategies such as tidal flow (TF), effluent recirculation (ER), and artificial aeration (AA) applied on three types of CWs including vertical flow constructed wetland (VFCW), horizontal flow constructed wetland (HFCW), and hybrid constructed wetland (HCW). The area reduction and pollutant removal efficiency showed substantial variation among different types of CWs and aeration strategies. The ER-VFCW designated the smallest footprint of 1.1 ± 0.5 m2 PE-1 (population equivalent) followed by TF-VFCW with the footprint of 2.1 ± 1.8 m2 PE-1, and the large footprint was of AA-HFCW (7.8 ± 4.7 m2 PE-1). When footprint and removal efficiency both are the major indicators for the selection of wetland type, the best options for practical application could be TF-VFCW, ER-HCW, and AA-HCW. The data and results outlined in this review could be instructive for futures studies and practical applications of CWs for wastewater treatment, especially in land-limited regions.

  6. Are constructed treatment wetlands sustainable sanitation solutions? (United States)

    Langergraber, Guenter


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


    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 ...

  8. Constructed wetlands for pollution control: processes, performance, design and operation

    National Research Council Canada - National Science Library


    .... Types of constructed wetland, major design parameters, role of vegetation, hydraulic patterns, loadings, treatment efficiency, construction, operation and maintenance costs are discussed in depth...

  9. Construction and operation costs of constructed wetlands treating wastewater. (United States)

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


    Design data from nine constructed wetlands (CW) facilities of various capacities (population equivalent (PE)) are used to estimate construction and operation costs, and then to derive empirical equations relating the required facility land area and the construction cost to PE. In addition, comparisons between the costs of CW facilities based on various alternative construction materials, i.e., reinforced concrete and earth structures (covered with either high density polyethylene or clay), are presented in relation to the required area. The results show that earth structures are economically advantageous. The derived equations can be used for providing a preliminary cost estimate of CW facilities for domestic wastewater treatment.

  10. Elemental composition of native wetland plants in constructed mesocosm treatment wetlands. (United States)

    Collins, Beverly S; Sharitz, Rebecca R; Coughlin, Daniel P


    Plants that accumulate a small percentage of metals in constructed treatment wetlands can contribute to remediation of acidic, metal contaminated runoff waters from coal mines or processing areas. We examined root and shoot concentrations of elements in four perennial wetland species over two seasons in mesocosm wetland systems designed to remediate water from a coal pile runoff basin. Deep wetlands in each system contained Myriophyllum aquaticum and Nymphaea odorata; shallow wetlands contained Juncus effusus and Pontederia cordata. Shoot elemental concentrations differed between plants of deep and shallow wetlands, with higher Zn, Al, and Fe concentrations in plants in shallow wetlands and higher Na, Mn, and P concentrations in plants in deep wetlands. Root and shoot concentrations of most elements differed between species in each wetland type. Over two seasons, these four common wetland plants did help remediate acidic, metal-contaminated runoff from a coal storage pile.

  11. Performance characterisation of a constructed wetland. (United States)

    Mangangka, Isri R; Egodawatta, Prasanna; Parker, Nathaniel; Gardner, Ted; Goonetilleke, Ashantha


    Performance of a constructed wetland is commonly reported as being variable due to the site specific nature of influential factors. This paper discusses the outcomes from an in-depth study which characterised the treatment performance of a wetland based on the variation in the runoff regime. The study included a comprehensive field monitoring of a well-established constructed wetland in Gold Coast, Australia. Samples collected at the inlet and outlet were tested for Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP). Pollutant concentrations in the outflow were found to be consistent irrespective of the variation in inflow water quality. The analysis revealed two different treatment characteristics for events with different rainfall depths. TSS and TN load reduction was found to be strongly influenced by the hydraulic retention time where performance was relatively superior for rainfall events below the design event. For small events, treatment performance was higher at the beginning of the event and gradually decreased during the course of the event. For large events, the treatment performance was comparatively poor at the beginning and improved during the course of the event. The analysis also confirmed the variable treatment trends for different pollutant types.

  12. Process-Based Modeling of Constructed Wetlands (United States)

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


    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

  13. Water and nutrient management in natural and constructed wetlands

    National Research Council Canada - National Science Library

    Vymazal, Jan


    ... are also used in constructed wetlands for wastewater treatment but within a more controlled environment. In addition, wetlands provide the supporting services necessary for the production of all other ecosystem services such as soil formation and retention, nutrient cycling, primary production or water cycling. In short, wetlands are clearly among t...

  14. Albuquerque's constructed wetland pilot project for wastewater polishing (United States)

    Michael D. Marcus; Shannon M. House; Nathan A. Bowles; Robert T. Sekiya; J. Steven Glass


    The City of Albuquerque has funded the Constructed Wetland Pilot Project (CWPP) since 1995 at the City's Southside Water Reclamation Plant (SWRP). Results from CWPP and other wetland treatment projects indicate that appropriately designed surface-flow wetlands could increase the cost-efficiencies of wastewater treatment, as well as help the City meet present and...

  15. Comparison of vertical and horizontal systems of constructed wetlands


    Vidmar, Urša


    The constructed wetlands (CW) or artificial wetlands with the wastewater treatment as their primary function are complex systems of water, substrate, plants, animals and microorganisms (bacteria). In practice there are two general systems in use, the system with the surface and the system with the subsurface flow, which is further divided into the system with the horizontal water flow and in the system with the vertical water flow. Understanding of constructed wetlands function...

  16. [Problems and countermeasures in the application of constructed wetlands]. (United States)

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


    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.

  17. Horizontal subsurface flow constructed wetlands for mitigation of ...

    African Journals Online (AJOL)

    The feasibility of using constructed wetlands (CWs) for the mitigation of pesticide runoff has been studied in the last decade. However, a lack of related data was verified when subsurface flow constructed wetlands (SSF CWs) are considered for this purpose. In the present work, SSF CWs were submitted to continuous ...

  18. Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands (United States)

    Lihu Cui; Ying Ouyang; Weizhi Yang; Zhujian Huang; Qiaoling Xu; Guangwei Yu


    Three new baffle flow constructed wetlands (CWs), namely the baffle horizontal flow CW (Z1), baffle vertical flow CW (Z2) and baffle hybrid flow CW (Z3), along with one traditional horizontal subsurface flow CW (Z4) were designed to test the removal efficiency of nitrogen (N) and phosphorus (P) from the septic tank effluent under varying hydraulic retention times (HRTs...

  19. Nitrogen compounds in drain sewage after constructed wetlands. (United States)

    Paweska, K; Malczewska, B


    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. Horizontal subsurface flow constructed wetlands for mitigation of ...

    African Journals Online (AJOL)


    Dec 22, 2008 ... wetlands constructed wetland (CW) systems have been suc- cessfully used for the treatment of several types of point and nonpoint sources of pollution (IWA, 2000). Although used for wastewater treatment and nutrient removal, the use of CWs for the mitigation of contaminant pesticides is still considered.

  1. Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield Wetlands Restoration Site (United States)


    ER D C /E L TR -0 5- 15 Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield Wetlands...unlimited. ERDC/EL TR-05-15 September 2005 Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield...sediments and soils of tidal marsh and seasonal wetlands bordering the HAAF Wetlands Restoration Site was assessed by same-sample analysis for total mercury

  2. Constructed wetlands as wood stork habitat: Good, bad, or ugly? (United States)

    US Fish and Wildlife Service, Department of the Interior — Objectives of our project are to determine the productivity of the wood stork colony nesting at the Jacksonville Zoo, to determine actual use of constructed wetlands...

  3. Potential of constructed wetlands as an alternative for wastewater ...

    African Journals Online (AJOL)

    surface flow Constructed Wetland (HSSFCW) system in polishing pre-treated wastewater in the UPward Flow Anaerobic sludge Blanket (UASB) reactor plant as a potential wastewater treatment system that can meet the requirement for ...

  4. Particles matter: Transformation of suspended particles in constructed wetlands

    NARCIS (Netherlands)

    Mulling, B.T.M.


    This thesis shows that constructed wetlands transform suspended particles in (treated) municipal wastewater through selective precipitation in ponds, biological filtering by plankton communities and physical and biological retention in reed beds. These processes effectively remove faecal indicator

  5. Use of Constructed Wetlands for Polishing Recharge Wastewater (United States)

    Cardwell, W.


    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

  6. Enzyme and root activities in surface-flow constructed wetlands. (United States)

    Kong, Ling; Wang, Yu-Bin; Zhao, Li-Na; Chen, Zhang-He


    Sixteen small-scale wetlands planted with four plant species were constructed for domestic wastewater purification. The objective of this study was to determine the correlations between contaminant removal and soil enzyme activity, root activity, and growth in the constructed wetlands. The results indicated that correlations between contaminant removal efficiency and enzyme activity varied depending on the contaminants. The removal efficiency of NH4+ was significantly correlated with both urease and protease activity in all wetlands, and the removal of total phosphorus and soluble reactive phosphorus was significantly correlated with phosphatase activity in most wetlands, while the removal of total nitrogen, NO3(-) , and chemical oxygen demand (COD) was significantly correlated with enzyme activity only in a few instances. Correlations between soil enzyme activity and root activity varied among species. Activities of all enzymes were significantly correlated with root activity in Vetiveria zizanioides and Phragmites australis wetlands, but not in Hymenocallis littoralis wetlands. Significant correlations between enzyme activity and root biomass and between enzyme activity and root growth were found mainly in Cyperus flabelliformis wetlands. Root activity was significantly correlated with removal efficiencies of all contaminants except NO3(-) and COD in V. zizanioides wetlands. Enzyme activities and root activity showed single-peak seasonal patterns. Activities of phosphatase, urease, and cellulase were significantly higher in the top layer of the substrate than in the deeper layers, and there were generally no significant differences between the deeper layers (deeper than 15 cm).

  7. Paracetamol removal in subsurface flow constructed wetlands (United States)

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


    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. Redox properties of a constructed wetland: theoretical and practical aspects. (United States)

    Síma, Jan; Diáková, Katerina; Pavelcová, Lenka; Havelka, Michal


    Constructed wetlands represent a progressive approach to the wastewater treatment. A fundamental prerequisite of the efficient water quality improvement is the presence of redox potential gradients (connected with the aeration of the system) inside the vegetation bed. Redox properties of a constructed wetland were tested in three longitudinal transects crossing the vegetation bed from the inflow zone to the outflow using diverse indicators (e.g., Fe(III)/Fe(II), SO(2-)(4)/S(2-)). Approximately 10-25% of iron was reoxidized in samples taken 10 m from the inflow zone in 2006. Redox processes of iron in artificial (constructed wetland) and natural (peat bog) ecosystems were compared. The peat bog was characterized with higher percentages of Fe(II) (usually ca. 90-100%). Thus, the aeration of the peat land was lower in comparison with the constructed wetland. The constructed wetland efficiently reduced sulfates (average concentrations of 44.7 and 11.2 mg/l at the inflow and the outflow, resp., in 2007). Organics, expressed as COD(Cr) and BOD(5), and NH+(4) were removed with efficiencies of 86.4, 92.2, and 60.4%, respectively. However, total phosphorus (redox processes play a negligible role in this case) was removed only with 39.6% efficiency. Redox properties of the wetland did not significantly depend on the heterogeneity of the treated wastewater flow.

  9. Greenhouse gas emissions from constructed wetlands treating dairy wastewater (United States)

    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

  10. Performance evaluation of constructed wetlands: A review of arid ...

    African Journals Online (AJOL)


    with other techniques leads to the desired sustainability; which calls for evaluation of the existing constructed ..... Wiley-VCH Verlag GmbH; Weinheim,. Germany. Sauer P, Kimber A (2001). Technical Assessment of Constructed. Wetlands for Wastewater Treatment in Iowa. IOWA Energy Center,. November,. 2001. Online at:.

  11. Investigation into the kinetics of constructed wetland degradation ...

    African Journals Online (AJOL)

    ABSTRACT. In this study, biomimetic principles were incorporated into a kinetic study of a pilot-scale, horizontal subsurface-flow constructed wetland (6.0 m × 1.0 m × 0.5 m) in Leipzig, Germany. The bed contained glacial gravel (4–8 mm) planted with. Phragmites australis. Construction was completed in October 2013 and ...

  12. Design and optimisation of novel configurations of stormwater constructed wetlands (United States)

    Kiiza, Christopher


    Constructed wetlands (CWs) are recognised as a cost-effective technology for wastewater treatment. CWs have been deployed and could be retrofitted into existing urban drainage systems to prevent surface water pollution, attenuate floods and act as sources for reusable water. However, there exist numerous criteria for design configuration and operation of CWs. The aim of the study was to examine effects of design and operational variables on performance of CWs. To achieve this, 8 novel designs of vertical flow CWs were continuously operated and monitored (weekly) for 2years. Pollutant removal efficiency in each CW unit was evaluated from physico-chemical analyses of influent and effluent water samples. Hybrid optimised multi-layer perceptron artificial neural networks (MLP ANNs) were applied to simulate treatment efficiency in the CWs. Subsequently, predictive and analytical models were developed for each design unit. Results show models have sound generalisation abilities; with various design configurations and operational variables influencing performance of CWs. Although some design configurations attained faster and higher removal efficiencies than others; all 8 CW designs produced effluents permissible for discharge into watercourses with strict regulatory standards.

  13. Treatment of Olive Mill Wastewater with Constructed Wetlands


    Andreas N. Angelakis; Iosif E. Kapellakis; Paranychianakis, Nikolaos V.; Tsagarakis, Konstantinos P.


    The objective of this study was to investigate the application of constructed wetlands as a mean to manage olive mill wastewater (OMW). Two free water surface (FWS) constructed wetlands, one without (CW1) and one with effluent recirculation (CW2), were operated for a two-year period with diluted OMW (1:10) and evaluated in terms of the removal of COD, TSS, TKN, NH4+-N, NO3−-N, TP and total phenols. The organic loading rate of CWs was adjusted to 925 kg BOD/ha·d. In CW1 the removal efficiency ...

  14. Campus Sewage Treatment in Multilayer Horizontal Subsurface Flow Constructed Wetlands

    DEFF Research Database (Denmark)

    Bai, Shaoyuan; Lyu, Tao; Ding, Yanli


    Horizontal subsurface flow constructed wetlands (HSCWs) are widely use for wastewater treatment. The objective of this study is to assess the effects of substrate-size selection and layout optimization on pollutant removal and microbial-community-distribution responses in HSCWs. Three pilot......-scale constructed wetlands (CWs) are established at Guilin University of Technology, China, to treat campus sewage. The three CWs include monolayer (CW1), three-layer (CW2), and six-layer (CW3) substrate structures with the hydraulic conductivity of the substrate increasing from the surface to the bottom...

  15. Accumulation of Cd, Pb and Zn by 19 wetland plant species in constructed wetland. (United States)

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


    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.

  16. On the use of photothermal techniques for monitoring constructed wetlands (United States)

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


    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.

  17. Hydraulic characteristics of a constructed wetland: Implications for pollutant removal (United States)

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


    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

  18. Seeking a way to promote the use of constructed wetlands for domestic wastewater treatment in developing countries. (United States)

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


    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.

  19. Performance evaluation of constructed wetlands: A review of arid ...

    African Journals Online (AJOL)

    Aiming at environmental pollution control through the use of constructed wetlands systems (CWs) in arid and semi arid climatic region, a detailed review of CWs was undertaken. Given the practical application and simplicity of the technology, principles for building phytotechnology-ecohydrology environment used for ...

  20. Effectiveness of vegetated constructed wetland in the reducation of ...

    African Journals Online (AJOL)

    This paper describes the performance of a Horizontal Sub-Surface Flow Constructed Wetland (HSSFCW) as a post-treatment unit to reduce BOD5 from Upflow Anaerobic Sludge Blanket (UASB) pre-treated domestic wastewater in a pilot treatment system at the University College of Lands and Architectural Studies (UCLAS) ...

  1. Performance of Subsurface Flow Constructed Wetland for Domestic ...

    African Journals Online (AJOL)

    Constructed wetlands (CW) have recently emerged as efficient technology for secondary treatment of wastewater in developing countries because of its low cost, ease operation, maintenance and generally good performance. At present there are a number of small scale units of CW for wastewater treatment in Tanzania but ...

  2. performance of subsurface flow constructed wetland for domestic

    African Journals Online (AJOL)


    ABSTRACT. Constructed wetlands (CW) have recently emerged as efficient technology for secondary treatment of wastewater in developing countries because of its low cost, ease operation, maintenance and generally good performance. At present there are a number of small scale units of CW for wastewater treatment in ...


    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 ...


    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...

  5. and slag-based constructed wetlands for acid mine drainage ...

    African Journals Online (AJOL)

    Industrial and Mining Water Research Unit, School of Chemical and Metallurgical Engineering,. University of the Witwatersrand, Private ... rent and historic coal and gold mining operations (Potgieter-. Vermaak et al., 2006; Tutu et al., ..... HABERL R (2000) Constructed Wetlands for Pollution Control: Processes, Performance ...

  6. Spatial distribution of metals in the constructed wetlands. (United States)

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


    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.

  7. Effect of treatment in a constructed wetland on toxicity of textile wastewater (United States)

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


    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.

  8. Intensified nitrogen removal of constructed wetland by novel integration of high rate algal pond biotechnology. (United States)

    Ding, Yi; Wang, Wei; Liu, Xingpo; Song, Xinshan; Wang, Yuhui; Ullman, Jeffrey L


    High rate algal pond (HRAP) was combined with constructed wetland (CW) to intensify nitrogen removal through optimizing nitrification and denitrification. Nitrification and denitrification process mainly depends on the oxygen content and carbon source level in CWs. Algal biomass was enriched in HRAP, and dissolved oxygen (DO) concentration was increased via photosynthesis. Algal debris increased COD as degradable bioresource. The results showed that HRAP-CW hybrid systems effectively promoted the nitrogen removal performance due to rich DO and COD. The extension of hydraulic retention time in HRAP significantly improved NH4-N and TN removals by 10.9% and 11.1% in hybrid systems, respectively. The highest NH4-N and TN removals in hybrid systems respectively reached 67.2% and 63.5%, which were significantly higher than those in single CW. The study suggested that the hybrid system had the application potentials in nitrogen removal from wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The effects of different aeration strategies on the performance of constructed wetlands for phosphorus removal. (United States)

    Ilyas, Huma; Masih, Ilyas


    The effects of different aeration methods such as tidal flow (TF), effluent recirculation (ER), and artificial aeration (AA) on the performance of vertical-flow constructed wetland (VFCW), horizontal-flow constructed wetland (HFCW), and hybrid constructed wetland (HCW) are extensively and critically evaluated in this review paper. Aerated constructed wetlands (CWs) demonstrate superior performance compared with non-aerated systems. The removal of total phosphorus (TP) showed substantial variation among different types of CWs and aeration strategies, with mean and standard deviation of 68 ± 20% estimated from all reviewed studies on aerated systems. The TF-VFCW designated the highest removal efficiency and removal rate of 88 ± 6% and 2.6 ± 2.5 g m-2 day-1, respectively, followed by the ER-HCW with values of 79 ± 18% and 1.3 ± 0.7 g m-2 day-1, respectively. The superior performance of TF-VFCW could be attributed to a positive effect of TF in rejuvenating the wetland with fresh air, thus enhancing dissolved oxygen (DO) in the system, and augmenting phosphorus precipitation and adsorption to the substrate. A positive correlation of TP and orthophosphate (PO43--P) with DO indicates that the improvement in DO levels due to redox manipulation with aeration strategies facilitates the phosphorous removal processes (e.g., through precipitation and adsorption to the substrate). The conflicting results on the impact of AA and ER reported by many studies need the cautious interpretation of their impact and require further studies. Only few studies have examined the impact of oxidation-reduction potential on phosphorous removal, which requires more attention in future research, as it appears as an important factor in enhancing the phosphorus removal.

  10. The performance of the intensified constructed wetlands for organic matter and nitrogen removal: A review. (United States)

    Ilyas, Huma; Masih, Ilyas


    The effects of different aeration strategies including tidal flow (TF), effluent recirculation (ER) and artificial aeration (AA) on performance of vertical flow constructed wetland (VFCW), horizontal flow constructed wetland (HFCW) and hybrid constructed wetland (HCW) are comprehensively and critically reviewed in this paper. The removal efficiencies of nine types of intensified constructed wetlands (CWs) were examined in detail and their mean and standard deviation were estimated at 89 ± 11%, 84 ± 12%, 81 ± 17% and 63 ± 20% for total suspended solids (TSS), chemical oxygen demand (COD), ammonium-nitrogen (NH4+N) and total nitrogen (TN), respectively. From the studied CWs, ER-HCW, TF-HCW, AA-VFCW and ER-VFCW emerged as the four best performing systems. The overall removal efficiency of TSS, COD, NH4+N and TN by ER-HCW was 98 ± 2%, 85 ± 11%, 83 ± 15% and 73 ± 11%, respectively. Specifically, the ER enhances the interactions between pollutants and micro-organisms, consequently, the efficient removal of NH4+N and TN has been achieved in ER-HCW. The TF has a positive effect in refreshing the wetland with fresh air to enhance the dissolved oxygen (DO) in the system. In case of AA, intermittent aeration is more effective than continuous aeration, as it facilitates the establishment of aerobic and anaerobic conditions suitable for nitrification and denitrification. Statistical analysis shows that DO, organic loading rate and specific surface area requirement are the most significant factors that influence the performance of intensified CWs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Triclosan removal in wetlands constructed with different aquatic plants. (United States)

    Liu, Jianing; Wang, Jingmin; Zhao, Congcong; Hay, Anthony G; Xie, Huijun; Zhan, Jian


    Triclosan (TCS) is widely used in consumer products as an antimicrobial agent. Constructed wetlands have the potential for TCS removal, but knowledge about the relative importance of sediment, plants, and microbes is limited. TCS removal performance was investigated in well-operated constructed wetlands planted with three different types of aquatic plants: emergent Cattail (C-T), submerged Hornwort (H-T), and floating Lemnaminor (L-T). Results showed that the TCS removal efficiencies from water were all greater than 97 %. Maximal TCS adsorption to sediment in the C-T wetland (13.8 ± 0.6 ng/g) was significantly lower than in the H-T wetland (21.0 ± 0.3 ng/g) or the L-T wetland (21.4 ± 0.6 ng/g). The maximal TCS concentrations in plants were 5.7 ± 0.2 and 7.2 ± 0.5 μg/g for H-T and L-T, respectively, and it was below the minimal detection limit (MDL) in C-T. Deep 16S rRNA gene sequencing results revealed that C-T wetland had the highest community richness and diversity. Some bacteria, like beta-Proteobacteria, gamma-Proteobacteria, and Bacteroidetes were detected and might have significant correlations with TCS degradation. Overall, with regard to soils, plants, and microorganism, accumulation in sediment and plants in H-T and L-T was high, while in C-T biodegradation likely played an important role.

  12. Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield (HAAF) Wetlands Restoration Site. Part 2 (United States)


    ER D C/ EL T R- 07 -2 1 Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield (HAAF...distribution is unlimited. ERDC/EL TR-07-21 September 2007 Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton...Methylmercury determination ...................................................................................................25 Mercury analysis QA/QC

  13. Application of a constructed wetland system for polluted stream remediation (United States)

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


    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

  14. Modelling the Hydraulic Processes on Constructed Stormwater Wetland

    Directory of Open Access Journals (Sweden)

    Isri Ronald Mangangka


    Full Text Available Constructed stormwater wetlands are manmade, shallow, and extensively vegetated water bodies which promote runoff volume and peak flow reduction, and also treat stormwater runoff quality. Researchers have noted that treatment processes of runoff in a constructed wetland are influenced by a range of hydraulic factors, which can vary during a rainfall event, and their influence on treatment can also vary as the event progresses. Variation in hydraulic factors during an event can only be generated using a detailed modelling approach, which was adopted in this research by developing a hydraulic conceptual model. The developed model was calibrated using trial and error procedures by comparing the model outflow with the measured field outflow data. The accuracy of the developed model was analyzed using a well-known statistical analysis method developed based on the regression analysis technique. The analysis results show that the developed model is satisfactory.

  15. Removal of copper from wastewater using a constructed wetland


    POMIJOVÁ, Zuzana


    This work deals with the efficiency of copper removal from wastewater using constructed wetlands. The object of this study was the vegetation wastewater treatment plant in the village of Slavošovice. During 2014, I used atomic absorption spectrometry to determine Cu concentration in the effluent. Samples were taken from different parts of the treatment plant (the inflow and outflow, and selected sampling sites in the vegetation bed). The obtained results enable to calculate the efficiency of ...

  16. Treatment of Olive Mill Wastewater with Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Andreas N. Angelakis


    Full Text Available The objective of this study was to investigate the application of constructed wetlands as a mean to manage olive mill wastewater (OMW. Two free water surface (FWS constructed wetlands, one without (CW1 and one with effluent recirculation (CW2, were operated for a two-year period with diluted OMW (1:10 and evaluated in terms of the removal of COD, TSS, TKN, NH4+-N, NO3−-N, TP and total phenols. The organic loading rate of CWs was adjusted to 925 kg BOD/ha·d. In CW1 the removal efficiency averaged 80%, 83%, 78%, 80%, and 74% for COD, TSS, TKN, TP, and total phenols, respectively, during the operation period. Effluent recirculation further improved the treatment efficiency which approached 90%, 98%, 87%, 85%, and 87% for COD, TSS, TKN, TP, and total phenols, respectively. Constructed wetlands also showed high removal efficiency for NH4+-N. Nitrate concentration maintained low in both CWs basins, probably due to the prevalence of high denitrification rates that efficiently removed the NO3--N produced by NH4+-N oxidation. Despite the increased removal percentages, pollutant concentration in effluent exceeded the allowable limits for discharge in water bodies, suggesting that additional practices, including enhanced pre-application treatment and/or higher dilution rates, are required to make this practice effective for OMW management.

  17. Exploring fecal indicator bacteria in a constructed stormwater wetland. (United States)

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


    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.

  18. Characterisation of the soil bacterial community structure and composition of natural and constructed wetlands. (United States)

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


    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Kinetics of nitrogen removal processes in constructed wetlands

    Directory of Open Access Journals (Sweden)

    Gajewska Magdalena


    Full Text Available The aim of this paper is to present a state-of-the-art review of the kinetics of nitrogen removal in constructed wetlands. Biological processes of nitrogen removal from wastewater can be described using equations and kinetic models. Hence, these kinetic models which have been developed and evaluated allow for predicting the removal of nitrogen in treatment wetlands. One of the most important, first order removal model, which is still applied, was analysed and its rate coefficients and factors were compared. This study also demonstrates the validity of Monod and multiple Monod kinetics, commonly seen today. Finally, a computational example of the reaction kinetics of nitrogen removal was also included in the study.

  20. Fate of Volatile Organic Compounds in Constructed Wastewater Treatment Wetlands (United States)

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


    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.

  1. Kinetics of nitrogen removal processes in constructed wetlands (United States)

    Gajewska, Magdalena; Skrzypiec, Katarzyna


    The aim of this paper is to present a state-of-the-art review of the kinetics of nitrogen removal in constructed wetlands. Biological processes of nitrogen removal from wastewater can be described using equations and kinetic models. Hence, these kinetic models which have been developed and evaluated allow for predicting the removal of nitrogen in treatment wetlands. One of the most important, first order removal model, which is still applied, was analysed and its rate coefficients and factors were compared. This study also demonstrates the validity of Monod and multiple Monod kinetics, commonly seen today. Finally, a computational example of the reaction kinetics of nitrogen removal was also included in the study.

  2. Potential of constructed wetland systems for treating tannery industrial wastewater. (United States)

    Kaseva, Mengiseny E; Mbuligwe, Stephen E


    This paper reports on findings of a study on the performance of two units of a Horizontal Sub-Surface Flow Constructed Wetland (HSSFCW) units in treating wastewater effluent from a tannery industry. One of the HSSFCW units was planted with macrophytes, while the other was used as a control (without plants). Wastewater was fed into the wetland units at the mean flow rate of 0.045+/-0.005 m(3)/day. The studied parameters were chromium, turbidity, salinity, Total Dissolved Solids (TDS), Electric Conductivity (EC), pH and temperature. The mean Hydraulic Retention Time (HRT) was 1.60 days (in the control) and 1.80 days (in the vegetated) units, obtained as a ratio of the volume of the wastewater and the volumetric flow rate of wastewater through the units while taking into consideration the porosity of the media. The vegetated HSSFCW exhibited higher chromium removal efficiency (99.83%), than the control unit with the removal efficiency of 92.53%. High chromium removal was associated with both high temperature as well as high pH values in the HSSFCW units. The reduction in turbidity was found to be 71% in the vegetated wetland unit while the corresponding value for the control unit was 66%. Results obtained indicated low reduction efficiencies of both EC (0.3% in the vegetated unit and 1.6% in the control unit) and salinity (11% in the vegetated unit and 22% in the control unit) in the two mesocosms. Generally, however, the study demonstrated that constructed wetlands can be used as an option for improving the quality of tannery effluents especially in the removal of chromium. Chromium removal might have been effected by, among others, gravitational settling of solids and formation of co-precipitation with insoluble compounds as well as adsorption on the substrates and plant surfaces.

  3. Effect of earthworm Eisenia fetida and wetland plants on nitrification and denitrification potentials in vertical flow constructed wetland. (United States)

    Xu, Defu; Li, Yingxue; Howard, Alan; Guan, Yidong


    The response of nitrification potentials, denitrification potentials, and N removal efficiency to the introduction of earthworms and wetland plants in a vertical flow constructed wetland system was investigated. Addition of earthworms increased nitrification and denitrification potentials of substrate in non-vegetated constructed wetland by 236% and 8%, respectively; it increased nitrification and denitrification potentials in rhizosphere in vegetated constructed wetland (Phragmites austrail, Typha augustifolia and Canna indica), 105% and 5%, 187% and 12%, and 268% and 15% respectively. Denitrification potentials in rhizosphere of three wetland plants were not significantly different, but nitrification potentials in rhizosphere followed the order of C. indica>T. augustifolia>P. australis when addition of earthworms into constructed wetland. Addition of earthworms to the vegetated constructed significantly increased the total number of bacteria and fungi of substrates (Pnitrification potentials (r=913, Pnitrification potentials than denitrification potentials. The removal efficiency of N was improved via stimulated nitrification potentials by earthworms and higher N uptake by wetland plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Modeling Escherichia coli removal in constructed wetlands under pulse loading. (United States)

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


    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Application of constructed wetlands for wastewater treatment in tropical and subtropical regions (2000-2013). (United States)

    Zhang, Dong-Qing; Jinadasa, K B S N; Gersberg, Richard M; Liu, Yu; Tan, Soon Keat; Ng, Wun Jern


    Constructed wetlands (CWs) have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option for developing countries. With the goal of promoting sustainable engineered systems that support human well-being but are also compatible with sustaining natural (environmental) systems, the application of CWs has become more relevant. Such application is especially significant for developing countries with tropical climates, which are very conducive to higher biological activity and productivity, resulting in higher treatment efficiencies compared to those in temperate climates. This paper therefore highlights the practice, applications, and research of treatment wetlands under tropical and subtropical conditions since 2000. In the present review, removal of biochemical oxygen demand (BOD) and total suspended solid (TSS) was shown to be very efficient and consistent across all types of treatment wetlands. Hybrid systems appeared more efficient in the removal of total suspended solid (TSS) (91.3%), chemical oxygen demand (COD) (84.3%), and nitrogen (i.e., 80.7% for ammonium (NH)4-N, 80.8% for nitrate (NO)3-N, and 75.4% for total nitrogen (TN)) as compared to other wetland systems. Vertical subsurface flow (VSSF) CWs removed TSS (84.9%), BOD (87.6%), and nitrogen (i.e., 66.2% for NH4-N, 73.3% for NO3-N, and 53.3% for TN) more efficiently than horizontal subsurface flow (HSSF) CWs, while HSSF CWs (69.8%) showed better total phosphorus (TP) removal compared to VSSF CWs (60.1%). Floating treatment wetlands (FTWs) showed comparable removal efficiencies for BOD (70.7%), NH4-N (63.6%), and TP (44.8%) to free water surface (FWS) CW systems. Copyright © 2015. Published by Elsevier B.V.

  6. Efficiency of a constructed wetland for wastewaters treatment

    Directory of Open Access Journals (Sweden)

    Fernanda Travaini-Lima

    Full Text Available AIM: The limnological characteristics of three different inlets water of the constructed wetland were compared in terms of concentration data and loading rate data and evaluated the removal efficiencies of nutrients, solids, BOD5, chlorophyll-a and thermotolerant coliforms (TC by the treatment system; METHODS: The constructed wetland, measuring 82.8 m² and with detention time of 1 hour and 58 minutes in the rainy season and 2 hours and 42 minutes in the dry one, was provided with four species, Cyperus giganteus Vahl, Typha domingensis Pers., Pontederia cordata L. e Eichhornia crassipes (Mart. Solms. The sampling sites evaluated in the dry (D and rainy (R seasons were: inlet water from aquaculture farm = IA; inlet channel of rainwater runoff = IR; inlet from UASB wastewater = IB; outlet wetland = OUT. The conductivity, pH, temperature, dissolved oxygen, alkalinity, BOD5, total soluble and dissolved solids, nitrogen, phosphorus, chlorophyll-a and TC were analyzed. Multivariate analyses, such as Cluster and Principal Components Analysis (PCA, were carried out to group sampling sites with similar limnological characteristics; RESULTS: In the PCA with the concentration data was retained 90.52% variability of data, correlating the inlet IB with high concentrations of conductivity, alkalinity, pH, TC, nutrients and solids. Regarding loading rate data, the PCA was retained 80.9% of the data's total variability and correlated the sampling sites IA D, IA R and OUT R with higher BOD5, chlorophyll-a, TDS, nitrate, nitrite, total-P, temperature, oxygen and water flow. The highest removal efficiencies rates occurred in the dry season, mainly in concentration, with 78% of ammonia, 95.5% of SRP, 94.9% of TSS and 99.9% of TC; CONCLUSIONS: The wetland was highly efficacious in the removal of nutrients, solids, BOD5, chlorophyll-a and TC, mainly during the dry season. The system restructuring to increase the detention time during the rainy season and a pre

  7. Performance of a vertical subsurface flow constructed wetland under different operational conditions

    National Research Council Canada - National Science Library

    Abdelhakeem, Sara G; Aboulroos, Samir A; Kamel, Mohamed M


    The performance of a vertical subsurface flow constructed wetland (VSSFCW) for sewage effluent treatment was studied in an eight month experiment under different operational conditions including: vegetation...

  8. State of the art for animal wastewater treatment in constructed wetlands. (United States)

    Hunt, P G; Poach, M E


    Although confined animal production generates enormous per-unit-area quantities of waste, wastewater from dairy and swine operations has been successfully treated in constructed wetlands. However, solids removal prior to wetland treatment is essential for long-term functionality. Plants are an integral part of wetlands; cattails and bulrushes are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen transport to sediment. Improved oxidation and nitrification may also be obtained by the use of the open water of marsh-pond-marsh designed wetlands. Wetlands normally have sufficient denitrifying population to produce enzymes, carbon to provide microbial energy, and anaerobic conditions to promote denitrification. However, the anaerobic conditions of wetland sediments limit the rate of nitrification. Thus, denitrification of animal wastewaters in wetlands is generally nitrate-limited. Wetlands are also helpful in reducing pathogen microorganisms. On the other hand, phosphorus removal is somewhat limited by the anaerobic conditions of wetlands. Therefore, when very high mass removals of nitrogen and phosphorus are required, pre- or in-wetland procedures that promote oxidation are needed to increase treatment efficiency. Such procedures offer potential for enhanced constructed wetland treatment of animal wastewater.

  9. Driving forces behind the construction of an eco-compensation mechanism for wetlands in China (United States)

    Wang, Changhai


    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.

  10. Integrated constructed wetland systems: design, operation, and performance of low-cost decentralized wastewater treatment systems. (United States)

    Behrends, L L; Bailey, E; Jansen, P; Houke, L; Smith, S


    Several different types of constructed wetland systems are being used as decentralized treatment systems including surface-flow, subsurface-flow, vertical-flow, and hybrid systems. Archetypical wetland systems have design strengths and weaknesses, and therefore it should be possible to design combined (integrated) systems to optimize a number of important treatment processes. This study provides comparative efficacy data for two integrated wetland treatment systems (IWTS) designed to enhance treatment of medium strength wastewater generated from a pilot-scale intensive fish farm. Results from the twenty eight months study included consistently high removal of COD (84% +) and ammonia nitrogen (93%) in both systems. Initially, phosphorus removal was also high (>90%) in both systems, but removal efficacy declined significantly over time. Nitrate removal was significantly better in the system that provided sequential aerobic and anoxic environments. Short hydraulic retention times coupled with sustained removal of COD and ammonia indicate that the ReCip components could be a least-cost wastewater treatment technology in the decentralized market sector.

  11. Constructed wetland using corncob charcoal substrate: pollutants removal and intensification. (United States)

    Liu, Mao; Li, Boyuan; Xue, Yingwen; Wang, Hongyu; Yang, Kai


    To investigate the feasibility of using corncob charcoal substrate in constructed wetlands, four laboratory-scale vertical flow constructed wetlands (VFCWs) were built. Effluent pollutant (chemical oxygen demand (COD), NH4+-N, total phosphorus (TP)) concentrations during the experiment were determined to reveal pollutant removal mechanisms and efficiencies at different stages. In the stable stage, a VFCW using clay ceramisite substrate under aeration attained higher COD (95.1%), and NH4+-N (95.1%) removal efficiencies than a VFCW using corncob charcoal substrate (91.5% COD, 91.3% NH4+-N) under aeration, but lower TP removal efficiency (clay ceramisite 32.0% and corncob charcoal 40.0%). The VFCW with raw corncob substrate showed stronger COD emissions (maximum concentration 3,108 mg/L) than the corncob charcoal substrate (COD was lower than influent). The VFCW using corncob charcoal substrate performed much better than the VFCW using clay ceramisite substrate under aeration when the C/N ratio was low (C/N = 1.5, TN removal efficiency 36.89%, 4.1% respectively). These results suggest that corncob charcoal is a potential substrate in VFCWs under aeration with a unique self -supplying carbon source property in the denitrification process.

  12. Efficiency of subsurface flow constructed wetland with trickling filter. (United States)

    Vucinic, Aleksandra Anic; Hrenovic, Jasna; Tepes, Predrag


    Effective wastewater purification in subsurface flow constructed wetlands must include adequate pretreatment and ensure a sufficient amount of dissolved oxygen. In a pilot-scale operation, a subsurface flow constructed wetland (CW) consisted of a primary settlement tank, a trickling filter for pretreatment and two serially assembled basins. The trickling filter was added to ensure sufficient aeration, increase purification of the wastewater and shorten the wastewater purification time. The estimated nominal flow was 0.7 m3/d. The experiments were conducted using the wastewater from the municipal sewage canal of the city of Zagreb, with utilization of three different flows: 0.72 (A), 1.44 (B) and 2.88 (C) m3/d. The efficiency of the purification process was monitored over a period of three years (TSS, BOD5, COD, NH4-N, NO2-N, PO4-P, dissolved oxygen, temperature and pH). The experimental results showed an increase in the removal efficiency with a doubling of the nominal flow from 0.7 to 1.44 m3/d, which could be related to the implementation of the trickling filter where high removal rates were achieved.

  13. Performance Evaluation of Integrated Constructed Wetland for Domestic Wastewater Treatment. (United States)

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


    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.

  14. Integrated Cr(VI) removal using constructed wetlands and composting. (United States)

    Sultana, Mar-Yam; Chowdhury, Abu Khayer Md Muktadirul Bari; Michailides, Michail K; Akratos, Christos S; Tekerlekopoulou, Athanasia G; Vayenas, Dimitrios V


    The present work was conducted to study integrated chromium removal from aqueous solutions in horizontal subsurface (HSF) constructed wetlands. Two pilot-scale HSF constructed wetlands (CWs) units were built and operated. One unit was planted with common reeds (Phragmites australis) and one was kept unplanted. Influent concentrations of Cr(VI) ranged from 0.5 to 10mg/L. The effect of temperature and hydraulic residence time (8-0.5 days) on Cr(VI) removal were studied. Temperature was proved to affect Cr(VI) removal in both units. In the planted unit maximum Cr(VI) removal efficiencies of 100% were recorded at HRT's of 1 day with Cr(VI) concentrations of 5, 2.5 and 1mg/L, while a significantly lower removal rate was recorded in the unplanted unit. Harvested reed biomass from the CWs was co-composted with olive mill wastes. The final product had excellent physicochemical characteristics (C/N: 14.1-14.7, germination index (GI): 145-157%, Cr: 8-10mg/kg dry mass), fulfills EU requirements and can be used as a fertilizer in organic farming. Copyright © 2014 Elsevier B.V. All rights reserved.


    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E.


    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

  16. Characterization of Microbial Communities and Composition in Constructed Dairy Wetland Wastewater Effluent


    Ibekwe, A. Mark; Grieve, Catherine M.; Lyon, Stephen R.


    Constructed wetlands have been recognized as a removal treatment option for high concentrations of contaminants in agricultural waste before land application. The goal of this study was to characterize microbial composition in two constructed wetlands designed to remove contaminants from dairy washwater. Water samples were collected weekly for 11 months from two wetlands to determine the efficiency of the treatment system in removal of chemical contaminants and total and fecal coliforms. The ...

  17. Penyisihan Organik Melalui Dua Tahap Pengolahan Dengan Modifikasi Abr Dan Constructed Wetland Pada Industri Rumah Tangga


    Munazah, Ashila Rieska; Soewondo, Prayatni


    An alternative of biological process using two stage treatment modification of ABR and constructed wetland. Home industry poultry slaughtering houses and tofu industry are contributor of high organic content in sewage. Therefore needed an alternative of biological process using two stage treatment modification of Anaerobic Baffle Reactor (ABR) and constructed wetland which are cheap, appropriate and simple operation. Wetland organic loading rate is depend on ABR effluent as a primary treatmen...

  18. Modeling and Understanding BOD Removal Processes in Free-Water Surface Constructed Wetlands (United States)

    Deng, Z.


    Free-water surface constructed wetlands have proven to be effective systems for removal of various pollutants in wastewater and agricultural drainage water. Modeling tools are needed for understanding the processes and mechanisms responsible for the removal of pollutants and for the design of new constructed wetlands. This paper presents a new model for mimicking the processes and mechanisms controlling the removal of BOD (biochemical oxygen demand) in free-water surface constructed wetlands. The processes and mechanisms, simulated in the model, include advection, dispersion, diffusion, monod kinetics of bacterial growth, water gains (via precipitation) and losses (evaporation and seepage) and mass exchange between water column and root layers of a wetland. A novel feature of the new model is the incorporation of a dynamic diffusive root-zone. Sensitivity analysis of the model input vaiables indicates that the BOD removal in free water surface constructed wetlands is most sensitive to the biological removal process of BOD in the root zone, controlled by acetic acid and anaerobic bacteria in root zone, and the flow velocity (controlling mean hydraulic residence time) and organic carbon in the water column. The application of the new model is demonstrated through two case studies involving two distinct constructed wetlands with one (Gustine Wetland) for treatment of secondary wastewater located in the USA and another (Lake Manzala Engineered Wetland) for treatment of agricultural drainage water in Egypt. The model is relatively simple yet effective, as evidenced by the high coefficient of determination of 0.73 - 0.99 for the Gustine Wetland and 0.98 for Manzala Wetland. The model is a reliable and efficient tool for designing constructed wetlands and for understanding effects of various processes and mechanisms on the treatment efficiency of wastewater in constructed wetlands.

  19. Constructed wetland and aquatic treatment systems for fish farms in Egypt : Desk study report

    NARCIS (Netherlands)

    Truijen, G.; Heijden, van der P.G.M.


    This report summarises the information found in scientific literature regarding the mechanisms and processes that enable constructed wetlands to remove heavy metals and pesticides from waste water. It examines what factors have an influence on the effectiveness of constructed wetlands to treat waste

  20. Evaluation of selected risk elements removal processes from wastewater in constructed wetlands.


    MRÁZKOVÁ, Ivana


    The purpose of this bachelor work is to provide a literature survey aimed at the processes responsible for removal of selected risk elements (arsenate, lead, nickel, Merkury, kadmium and manganese) during the wastewater treatment in constructed wetlands. Also, constructed wetlands are compared with conventional treatment plants.

  1. Dynamics of antibiotic resistance genes and their relationships with system treatment efficiency in a horizontal subsurface flow constructed wetland. (United States)

    Nõlvak, Hiie; Truu, Marika; Tiirik, Kertu; Oopkaup, Kristjan; Sildvee, Teele; Kaasik, Ants; Mander, Ülo; Truu, Jaak


    Municipal wastewater treatment is one of the pathways by which antibiotic resistance genes from anthropogenic sources are introduced into natural ecosystems. This study examined the abundance and proportion dynamics of seven antibiotic resistance genes in the wetland media biofilm and in the influent and effluent of parallel horizontal subsurface flow mesocosm cells of a newly established hybrid constructed wetland treating municipal wastewater. The targeted genes (tetA, tetB, tetM, ermB, sul1, ampC, and qnrS) encode resistance to major antibiotic classes such as tetracyclines, macrolides, sulfonamides, penicillins, and fluoroquinolones, respectively. All targeted antibiotic resistance genes were detectable in the tested mesocosm environments, with the tetA, sul1, and qnrS genes being the most abundant in the mesocosm effluents. After initial fluctuation in the microbial community, target gene abundances and proportions stabilized in the wetland media biofilm. The abundance of 16S rRNA and antibiotic resistance genes, and the proportion of antibiotic resistance genes in the microbial community, were reduced during the wastewater treatment by the constructed wetland. The concentration of antibiotic resistance genes in the system effluent was similar to conventional wastewater treatment facilities; however, the mesocosms reduced sulfonamide resistance encoding sul1 concentrations more effectively than some traditional wastewater treatment options. The concentrations of antibiotic resistance genes in the wetland media biofilm and in effluent were affected by system operation parameters, especially time and temperature. The results also revealed a relationship between antibiotic resistance genes abundance and the removal efficiencies of NO2-N, NH4-N, and organic matter. Correlation analysis between the abundance of individual antibiotic resistance genes in the mesocosms influent, effluent and wetland media biofilm indicated that depending on antibiotic resistance gene

  2. [Optimization of aerobic/anaerobic subsurface flow constructed wetlands]. (United States)

    Li, Feng-Min; Shan, Shi; Li, Yuan-Yuan; Li, Yang; Wang, Zheng-Yu


    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.

  3. Constructed wetlands for water pollution management of aquaculture farms conducting earthen pond culture. (United States)

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan; Chang, Yih-Feng; Sui, Hsuan-Yu


    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 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.

  4. Removal and factors influencing removal of sulfonamides and trimethoprim from domestic sewage in constructed wetlands. (United States)

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


    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. [Segregation effect of purification for nitrogen and phosphate pollution in the subsurface flow constructed wetlands]. (United States)

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


    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.

  6. Constructed Wetlands for Treatment of Organic and Engineered Nanomaterial Contaminants of Emerging Concerns (WaterRF Report 4334) (United States)

    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...

  7. Specifically Designed Constructed Wetlands: A Novel Treatment Approach for Scrubber Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    John H. Rodgers Jr; James W. Castle; Chris Arrington: Derek Eggert; Meg Iannacone


    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

  8. Use of vetiver grass constructed wetland for treatment of leachate. (United States)

    Bwire, K M; Njau, K N; Minja, R J A


    Performance of Constructed Wetland planted with vetiver grasses for the treatment of leachate was investigated in controlled experiments involving horizontal subsurface flow constructed wetland (HSSFCW). The HSSFCW experimental unit had two cells, one planted with vetiver grasses and another bare. Both units were packed with limestone gravel as substrate and were operated with equal hydraulic loading and hydraulic retention time. Collected samples of influents and effluents were analysed for COD, Cr, Pb, Fe and pH. The results showed that vetiver grasses tolerated leachate with high loading of COD up to 14,000 mg L(-1). The planted cell outperformed the unplanted cell in terms of COD, Cr, Pb and Fe removal. The systems showed optimum points for COD and Pb removal as a function of feed concentrations. The optimum COD removal values of 210 mgm(-2) day(-1) at feed COD concentration of 11,200 mg COD L(-1) and 89 mgm(-2) day(-1) at feed concentration of 7,200 mg COD L(-1) were obtained for planted and unplanted cells respectively. Similarly Pb removal values of 0.0132 mgm(-2) day(-1) at 1.0 mg Pb L(-1) and 0.0052 mgm(-2) day(-1) at 1.04 mgPb L(-1) were obtained for planted and unplanted units respectively. Removal of Fe as a function of feed Fe concentration showed a parabolic behaviour but Cr removal showed linear behaviour with feed Cr concentrations in both units. The system showed very good removal efficiencies with Cr and Fe but poor efficiencies were recorded for Pb.

  9. Constructed wetland: an alternative for wastewater treatment; Humedales construidos: una alternativa a considerar para el tratamiento de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Plaza de los Reyes del Rio, C.; Vidal Saez, G.


    Research and trends dealing with sewage and industrial wastewaters treated by constructed wetlands are shown in this paper. Plant and constructed wetlands configurations are also described. Sewage domestic wastewaters from individual houses or villages have used constructed wetlands as wastewater treatment. On the other hand, constructed wetlands as finally treatment working together with conventional technologies could be a good alternative for improving the treated quality wastewater. (Author) 56 refs.

  10. Optimizations on supply and distribution of dissolved oxygen in constructed wetlands: A review. (United States)

    Liu, Huaqing; Hu, Zhen; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Fan, Jinlin; Lu, Shaoyong; Wu, Haiming


    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. Copyright © 2016. Published by Elsevier Ltd.

  11. Constructed wetlands as ecologically sustainable options for water pollution control : A challenge for environmental engineers


    Margaret, Greenway; Griffith University


    Traditionally the treatment of wastewater has been the realm of the civil and chemical engineer. Constructed wetlands are now recognised as an ecologically sustainable option for water pollution control. Wetlands are biologically diverse ecosystems which provide an array of physical, biological and chemical processes to facilitate the removal, recycling, transformation or immobilisation of potential wastewater contaminants. Most of these processes are facilitated by the wetland vegetation and...

  12. Establishment of a constructed wetland in extreme dryland. (United States)

    Tencer, Yoram; Idan, Gil; Strom, Marjorie; Nusinow, Uri; Banet, Dorit; Cohen, Eli; Schröder, Peter; Shelef, Oren; Rachmilevitch, Shimon; Soares, Ines; Gross, Amit; Golan-Goldhirsh, Avi


    The project was set to construct an extensive wetland in the southernmost region of Israel at Kibbutz Neot Smadar (30 degree 02'45" N and 35 degree 01'19" E). The results of the first period of monitoring, summary, and perspectives are presented. The constructed wetland (CW) was built and the subsequent monitoring performed in the framework of the Southern Arava Sustainable Waste Management Plan, funded by the EU LIFE Fund. The specific aims were: (1) To end current sewage disposal and pollution of the ground, the aquifer, and the dry river bed (wadi) paths by biologically treating the sewage as part of the creation of a sustainable wetland ecosystem. (2) Serve as an example of CW in the Negev highlands and the Arava Valley climates for neighboring communities and as a test ground for plants and building methods appropriate to hyper arid climate. (3) Serve as an educational resource and tourist attraction for groups to learn about water reuse, recycling, local wildlife and migrating birds, including serving the heart of a planned Ecological-Educational Bird Park. This report is intended to allow others who are planning similar systems in hyper arid climates to learn from our experience. The project is located in an extreme arid desert with less than 40 mm of rain annually and temperature ranges of -5 degree C to +42 degree C. The site receives 165-185 m3 of municipal and agricultural wastes daily, including cowshed and goat wastes and winery outflow. The CW establishment at Neot Smadar was completed in October 2006. For 8 months, clean water flowed through the system while the plants were taking root. In June 2007, the wetland was connected to the oxidation pond and full operation began. Because of seepage and evaporation, during the first several months, the water level was not high enough to allow free flow from one bed to the next. To bed A, the water was pumped periodically from the oxidation pond (Fig. 1) and from there flowed by gravitation through the rest

  13. [Limestone and pyrite-limestone constructed wetlands for treating river water]. (United States)

    Zhang, Jing; Li, Rui-hua; Li, Jie; Hu, Jun-song; Sun, Qian-qian


    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.

  14. Wineries wastewater treatment by constructed wetlands: a review. (United States)

    Masi, F; Rochereau, J; Troesch, S; Ruiz, I; Soto, M


    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.

  15. How Long, Narrowly Constructed Wetlands Purify Irrigation Return Water: A Case Study of Ulansuhai Lake, China

    Directory of Open Access Journals (Sweden)

    Xufeng Mao


    Full Text Available The use of constructed wetlands (CWs in the treatment of raw wastewater in China has proved to be very successful in recent decades. However, it is not known whether surface-flow constructed wetlands can effectively purify irrigation return water. To investigate the performance of a constructed wetland in terms of meeting the goals of pollutant purification, the 8th drainage of Ulansuhai Lake was used for this study. Pollutant removal performances, as well as hydrological characteristic variations in relation to specific characteristics of plants, were investigated utilizing two years of monthly average data. The results indicated that surface-flow constructed wetlands can effectively change the physical characteristics of return water and lead to a sharp decrease in pollutant concentrations. The 1200 m long, narrowly constructed wetland resulted in the average reduction rates of total nitrogen (TN and total phosphorus (TP of up to 22.1% and 21.5%, respectively. The overall purification efficient of the constructed wetland presented seasonal variations in four different monitoring periods (May, July, September, and November. Constructed wetlands with multiple types of plants exhibited higher efficiencies in pollutants removal than those with a single type of plant. The current study can provide meaningful information for the treatment of agricultural wastewater.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, C.L.; LaGory, K.


    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.

  17. Designing a constructed wetland for the detention of agricultural runoff for water quality improvement. (United States)

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


    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.


    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...

  19. Carbon sequestration in surface flow constructed wetland after 12 years of swine wastewater treatment (United States)

    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...

  20. Regulatory Implications of Using Constructed Wetlands to Treat Selenium-Laden Wastewater (United States)

    A. Dennis Lemly; Harry M. Ohlendorf


    The practice of using constructed wetlands to treat selenium-laden wastewater is gaining popularity in the linited States and elsewhere. However, proponents of treatment wetlands often overlook important ecological liabilities and regulatory implications when developing new methods and applications. Their research studies typically seek to answer a basic performance...

  1. Morphological response of Typha domingensis to an industrial effluent containing heavy metals in a constructed wetland. (United States)

    Hadad, H R; Mufarrege, M M; Pinciroli, M; Di Luca, G A; Maine, M A


    Typha domingensis had become the dominant species after 2 years of operation of a wetland constructed for metallurgical effluent treatment. Therefore, the main purpose of this study was to investigate its ability to tolerate the effluent and to maintain the contaminant removal efficiency of the constructed wetland. Plant, sediment, and water at the inlet and outlet of the constructed wetland and in two natural wetlands were sampled. Metal concentration (Cr, Ni, and Zn) and total phosphorus were significantly higher in tissues of plants growing at the inlet in comparison with those from the outlet and natural wetlands. Even though the chlorophyll concentration was sensitive to effluent toxicity, biomass and plant height at the inlet and outlet were significantly higher than those in the natural wetlands. The highest root and stele cross-sectional areas, number of vessels, and biomass registered in inlet plants promoted the uptake, transport, and accumulation of contaminants in tissues. The modifications recorded accounted for the adaptability of T. domingensis to the conditions prevailing in the constructed wetland, which allowed this plant to become the dominant species and enabled the wetland to maintain a high contaminant retention capacity.

  2. Existing forms and changes of nitrogen inside of horizontal subsurface constructed wetlands. (United States)

    Wang, Hao; Zhong, Huiyuan; Bo, Guozhu


    Horizontal zeolite subsurface constructed wetland system (HZCWs) and horizontal limestone subsurface constructed wetland system (HLCWs) were applied to the removal of nitrogen in lightly polluted wastewater, and the existing forms, changes, and removal mechanism of nitrogen in the constructed wetlands were analyzed. The results indicated that compared with HLCWs, HZCWs exhibited better nitrogen removal effect, and the maximum removal rates of ammonia nitrogen and total nitrogen could reach 96.97 ± 5.29 and 93.12 ± 3.35%, respectively. Besides, analysis of the removal effect on nitrogen in different existing forms on different substrate heights in the constructed wetlands showed that variation of nitrogen removal efficiency had certain regularities, which were related to the interior construction features of the wetland systems, and agreed with the regularities in the changes of the influential factors such as DO inside of the wetlands. In addition, degradation mechanism of pollutions was also analyzed, and the results indicated that the quantity of microorganisms and enzymes, including FDA, catalase, and urease, on the surface of the substrates had significant influence on the removal regularities and effects of the major pollutions in constructed wetlands.

  3. Wastewater treatment in tsunami affected areas of Thailand by constructed wetlands

    DEFF Research Database (Denmark)

    Brix, Hans; Koottatep, H.; Laugesen, C.H.


    the systems which have been built at three locations: (a) Baan Pru Teau: A newly-built township for tsunami victims which was constructed with the contribution of the Thai Red Cross. Conventional septic tanks were installed for the treatment of blackwater from each household and its effluent and grey water...... (40 m3/day) are collected and treated at a 220 m2 subsurface flow constructed wetland. (b) Koh Phi Phi Don island: A wastewater collection system for the main business and hotel area of the island, a pumping station and a pressure pipe to the treatment facility, a multi-stage constructed wetland...... system and a system for reuse of treated wastewater. The constructed wetland system (capacity 400 m3/day) consists of vertical flow, horizontal subsurface flow, free water surface flow and pond units. Because the treatment plant is surrounded by resorts, restaurants and shops, the constructed wetland...

  4. Microbial fuel cells for clogging assessment in constructed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Corbella, Clara; García, Joan; Puigagut, Jaume, E-mail:


    Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the beginning of the study period up to ca. 250 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2 years (ca. 0.5 kg TS·m{sup –3}CW) to ca. 5 years (ca. 10 kg TS·m{sup –3}CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5 years of clogging (ca. 10 kg TS·m{sup –3}CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. - Highlights: • Microbial fuel cells are used as tool for clogging assessment in constructed wetlands. • Microbial fuel cells were loaded with sludge from constructed wetlands. • Sludge retained within the systems simulated a clogging time ranging from 0.2 to ca. 5 years. • Electrons transferred decreased potentially as function of sludge loading.

  5. Fecal coliform removal in a lightly loaded surface-flow constructed treatment wetland polishing agricultural runoff. (United States)

    Beutel, Marc W; Whritenour, Victoria; Brouillard, Elaine


    Constructed treatment wetlands can be an effective and sustainable method to remove pathogens that pose health risks from agricultural runoff. This study evaluated the removal of fecal coliform (FC) from agricultural runoff in a lightly loaded surface-flow treatment wetland prior to discharge to the Yakima River, Washington State, USA. The 1.6 ha system consisted of a sedimentation basin (1.4 d hydraulic retention time) followed by two wetlands (5-6 d hydraulic retention time). FC in inflow ranged from 100 to 1,000 cfu/100 mL. Mean annual FC log-removal in the sedimentation basin was 0.66 ± 0.17 (mean plus/minus standard deviation; n = 7). However, there was a comparable production of FC within the two wetlands where annual log-removal averaged -0.71 ± 0.39 in the north wetland and -0.57 ± 0.17 in the south wetland. FC removal in the sedimentation basin weakly correlated with turbidity removal (R(2) = 0.13, p wetlands negatively correlated with temperature (R(2) = 0.27-0.33, p wetlands in 2007 and 2008 corresponded with a marked increase in FC in wetland outflow. Results suggest that, regardless of the presence of muskrats, sedimentation basins alone are more effective than a combined sedimentation basin-wetland system in removing FC from dilute agricultural runoff.

  6. Design, construction and performance of a horizontal subsurface flow wetland system in Australia. (United States)

    Bolton, Lise M W; Bolton, Keith G E


    Malabugilmah is a remote Aboriginal community located in Clarence Valley, Northern NSW, Australia. In 2006, seven horizontal subsurface flow wetland clusters consisting of 3 m × 2 m wetland cells in series were designed and constructed to treat septic tank effluent to a secondary level (Total Suspended Solids (TSS) 50% Total Nitrogen (TN) reduction, no net Total Phosphorus (TP) export and ≥99.9% Faecal Coliform (FC) reduction. The wetland cell configuration allowed the wetlands to be located on steeper terrain, enabling effluent to be treated to a secondary level without the use of pumps. In addition to the water quality targets, the wetlands were designed and constructed to satisfy environmental, economic and social needs of the community. The wetland systems were planted with a local Australian wetland tree species which has become well established. Two wetland clusters have been monitored over the last 4 years. The wetlands have demonstrated to be robust over time, providing a high level of secondary treatment over an extended period.

  7. Molecular Characterization of Wetland Soil Bacterial Community in Constructed Mesocosms (United States)


    mainly determined by bulk soil community for Carex arenaria . Microbial Dechlorination Dechlorination within a wetland is best understood by Boer, W. (2005). Rhizosphere bacterial community composition in natural stands of carex arenaria (sand sedge) is determined by bulk soil...wetland mesocosms and to identify any bacterial dominance. Carex comosa, Scirpus atrovirens, and Eleocharis erythropoda were planted in multiple

  8. Start-up of a free water surface constructed wetland for treating olive mill wastewater

    Directory of Open Access Journals (Sweden)

    Michailides Michail


    Full Text Available An olive mill's existing evaporation pond was separated into five cells and transformed into a free water surface constructed wetland. The constructed wetland was used as a post-treatment stage for olive mill wastewater (OMW. Wastewater was previously treated by an aerobic trickling filter. The influent concentrations in the constructed wetland were 27400 mg.L-1, 4800 mg.L-1, 105 mg.L-1 and 770 mg.L-1 for COD, phenols, ortho-phosphate and TKN, respectively. Despite the rather high influent concentrations, the performance of the constructed wetland was very good since after the 60-day start-up operation period it achieved removal rates of about 94%, 95%, 95% and 98% for COD, phenols, ortho-phosphate and TKN, respectively. The major pollutant removal processes can be attributed to both biological processes occurring in the wetland and photo-oxidation. Laboratory-scale experiments with OMW from fifth cell of the wetland revealed that the net contribution of photo-oxidation after 112 hours of simulated solar radiation at 765 W/m2 (i.e. about 38 days of sunlight irradiation was 18% and 31% removal for COD and phenols, respectively. In the constructed wetland, the total removal reached 81% and 86% for COD and phenols, respectively, for the same time period (38 days.

  9. Field test results for nitrogen removal by the constructed wetland component of an agricultural water recycling system (United States)

    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...

  10. Reuse of constructed wetland effluents for irrigation of energy crops. (United States)

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


    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.


    Directory of Open Access Journals (Sweden)

    Mosisa Teferi Timotewos


    Full Text Available Oxidizing bacteria located in the roots of the plant have a unique ability of absorbing nutrients (pollutants in the wastewater, thus they may be considered as a useful method for wastewater treatment from the viewpoint of eco-toxicology and environmental safety. By using three prevalent plants, namely Typha, Phragmites australis, and Scirpus, we performed a series of mesocosms experiments in Arba Minch, southern part of Ethiopia for the removal efficiency of NO-3-N, NH4+-N, PO4-3-P, Ca2+, Mg2+, K+ and BOD5 by design constructed wetlands. Contrastingly, we found that the PO4-3-P, Ca2+, Mg2+ and BOD5 reached the removal efficiencies of up to 99.1%, 55.2%, 81.1% and 93.88% for Typha plant, which has much better removal efficiency than Phragmites australis and Scirpus. The results explore how the oxidizing bacteria behave in different plant environments and that led to enhance the efficiency of pollutants removal in wastewater.

  12. Constructed Wetlands Revisited: Microbial Diversity in the -omics Era. (United States)

    Sánchez, Olga


    Constructed wetlands (CWs) constitute an interesting alternative option to conventional systems for wastewater treatment. This technology is based on the utilization of the concerted activity of microorganisms for the removal of contaminants. Consequently, knowledge on the microbial assemblages dwelling CWs and the different environmental factors which can alter their activities is crucial for understanding their performance. In the last decades, the use of molecular techniques to characterize these communities and more recently, application of -omics tools, have broaden our view of microbial diversity and function in wastewater microbiology. In this manuscript, a review of the current knowledge on microbial diversity in CWs is offered, placing particular emphasis on the different molecular studies carried out in this field. The effect of environmental conditions, such as plant species, hydraulic design, water depth, organic carbon, temperature and substrate type on prokaryotic communities has been carefully revised, and the different studies highlight the importance of these factors in carbon, nitrogen and sulfur cycles. Overall, the novel -omics open a new horizon to study the diversity and ecophysiology of microbial assemblages and their interactions in CWs, particularly for those microorganisms belonging to the rare biosphere not detectable with conventional molecular techniques.

  13. Microbial nitrogen transformation in constructed wetlands treating contaminated groundwater. (United States)

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


    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.

  14. Construction simplicity and cost as selection criteria between two types of constructed wetlands treating highway runoff. (United States)

    Manios, Thrassyvoulos; Fountoulakis, Michalis S; Karathanasis, Anastasios D


    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 m(2) each, while the two identical SSF covered 32 m(2) 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 m(3)/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 m(3)/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 (euro 14,676) was approximately 10% higher than that of the FWS (euro 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 euro 1799/year and euro 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 TAEC(COD) and TAEC(TSS) values (euro 89.09/kg and euro 43.69/kg

  15. Appropriate and sustainable wastewater management in developing countries by the use of constructed wetlands

    DEFF Research Database (Denmark)

    Brix, Hans; Koottatep, Thammarat; Fryd, Ole


    Constructed wetland systems for wastewater management may have great potential in developing countries as robust and decentralized solution. A case study from Koh Phi Phi island in Thailand where a constructed wetland systems was established after the destructions by the tsunami in 2004 is descri......Constructed wetland systems for wastewater management may have great potential in developing countries as robust and decentralized solution. A case study from Koh Phi Phi island in Thailand where a constructed wetland systems was established after the destructions by the tsunami in 2004...... and nitrogen, but because of inadequate pre-treatment and removal of oil and grease prior to the system, the standards for oil and grease and BOD are not met. The experiences from the project illustrate, that despite the appropriateness of the system, and the fact that safeguards were prepared beforehand...

  16. Associated Fauna to Eichhornia crassipes in a Constructed Wetland for Aquaculture Effluent Treatment

    National Research Council Canada - National Science Library

    Lúcia Helena Sipaúba-Tavares; Bruno Scardoelli Truzzi; Ana Milstein; Aline Marcari Marques


    Water, sediment and associated fauna were studied in a water hyacinth ( ) stand of a constructed wetland, used for aquaculture effluent treatment in SE Brazil, in February-April (summer/rainy season...

  17. Determination of Chlorinated Solvent Contamination in an Upward Flow Constructed Wetland

    National Research Council Canada - National Science Library

    Opperman, Bryan


    .... Analysis will be accomplished by means of purge-and-trap gas chromatography. The contaminant concentration levels will be used to enhance the design and construction of man-made wetlands used to remove chlorinated solvents from aquifers...

  18. Removal efficiency of pharmaceuticals in a full scale constructed wetland in East Ukraine

    Czech Academy of Sciences Publication Activity Database

    Vystavna, Yuliya; Frková, Zuzana; Marchand, L.; Vergeles, Y.; Stolberg, F.


    Roč. 108, NOV (2017), s. 50-58 ISSN 0925-8574 Institutional support: RVO:60077344 Keywords : emerging pollutants * constructed wetland * wastewater treatment * Ukraine * pocis Subject RIV: DJ - Water Pollution ; Quality Impact factor: 2.914, year: 2016

  19. Feasibility of constructed wetlands for removing chlorothalonil and chlorpyrifos from aqueous mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sherrard, R.M.; Bearr, J.S.; Murray-Gulde, C.L.; Rodgers, J.H.; Shah, Y.T


    Chlorpyrifos (an insecticide) and chlorothalonil (a fungicide) are transported in stormwater runoff and can be lethal to receiving aquatic system biota. This study determined removal rates of chlorpyrifos and chlorothalonil in simulated stormwater runoff treated in constructed wetland mesocosms. Using sentinel species, Ceriodaphnia dubia and Pimephales promelas, observed declines in toxicity of the simulated runoff after treatment were 98 and 100%, respectively. First order removal rates were 0.039/h for chlorpyrifos and 0.295/h for chlorothalonil in these experiments. Constructed wetland mesocosms were effective for decreasing concentrations of chlorpyrifos and chlorothalonil in simulated stormwater runoff, and decreasing P. promelas and C. dubia mortality resulting from these exposures. The results from this study indicate that constructed wetlands could be part of an efficient mitigation strategy for stormwater runoff containing these pesticides. - Constructed wetlands have potential for treatment of pesticide mixtures in stormwater runoff.

  20. Enrichment of elements in detritus from a constructed wetland and consequent toxicity to Hyalella azteca. (United States)

    Sundberg, Sarah E; Hassan, Sayed M; Rodgers, John H


    In a pilot constructed wetland treatment system specifically designed to treat constituents of flue gas desulfurization wastewater, detritus adsorbs significantly high concentrations of Hg, Se, and As. Results of this research indicate that Hg, Se, and As were enriched in detritus from Schoenoplectus californicus and Typha angustifolia collected from the constructed wetland by factors up to 4600, 26,300, and 15,600, respectively. As an important food source for many organisms, element enrichment makes the detritus an even greater source of contaminants to the food web. Results demonstrate that the natural decomposition of plants in this constructed wetland treatment system produces detritus enriched with Hg, Se, and As at levels potentially hazardous to aquatic organisms. To completely assess ecological risks associated with the use of constructed wetland treatment systems, contaminant enrichment, bioavailability, and toxicity in detritus must be considered.

  1. Myriophyllum aquaticum Constructed Wetland Effectively Removes Nitrogen in Swine Wastewater

    Directory of Open Access Journals (Sweden)

    Haishu Sun


    Full Text Available Removal of nitrogen (N is a critical aspect in the functioning of constructed wetlands (CWs, and the N treatment in CWs depends largely on the presence and activity of macrophytes and microorganisms. However, the effects of plants on microorganisms responsible for N removal are poorly understood. In this study, a three-stage surface flow CW was constructed in a pilot-scale within monospecies stands of Myriophyllum aquaticum to treat swine wastewater. Steady-state conditions were achieved throughout the 600-day operating period, and a high (98.3% average ammonia removal efficiency under a N loading rate of 9 kg ha-1 d-1 was observed. To determine whether this high efficiency was associated with the performance of active microbes, the abundance, structure, and interactions of microbial community were compared in the unvegetated and vegetated samples. Real-time quantitative polymerase chain reactions showed the abundances of nitrifying genes (archaeal and bacterial amoA and denitrifying genes (nirS, nirK, and nosZ were increased significantly by M. aquaticum in the sediments, and the strongest effects were observed for the archaeal amoA (218-fold and nirS genes (4620-fold. High-throughput sequencing of microbial 16S rRNA gene amplicons showed that M. aquaticum greatly changed the microbial community, and ammonium oxidizers (Nitrosospira and Nitrososphaera, nitrite-oxidizing bacteria (Nitrospira, and abundant denitrifiers including Rhodoplanes, Bradyrhizobium, and Hyphomicrobium, were enriched significantly in the sediments. The results of a canonical correspondence analysis and Mantle tests indicated that M. aquaticum may shift the sediment microbial community by changing the sediment chemical properties. The enriched nitrifiers and denitrifiers were distributed widely in the vegetated sediments, showing positive ecological associations among themselves and other bacteria based on phylogenetic molecular ecological networks.

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

    DEFF Research Database (Denmark)

    Brix, Hans; Schierup, Hans-Henrik; Arias, Carlos Alberto


    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...... 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....

  3. [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]. (United States)

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


    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.

  4. Constructed wetland for water quality improvement: a case study from Taiwan. (United States)

    Wu, C Y; Liu, J K; Cheng, S H; Surampalli, D E; Chen, C W; Kao, C M


    In Taiwan, more than 20% of the major rivers are mildly to heavily polluted by domestic, industrial, and agricultural wastewaters due to the low percentage of sewers connected to wastewater treatment plants. Thus, constructed or engineered wetlands have been adopted as the major alternatives to clean up polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems for the wastewater polishment to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before it is discharged into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks for organics and metals. In this study, water and sediment samples were collected from the major wetland basins in KRRBCW. The investigation results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g. total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g. Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O(2)/m(2) d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TN). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that a variation in microbial diversity in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of

  5. Constructed wetlands in the treatment of agro-industrial wastewater: A review

    Directory of Open Access Journals (Sweden)

    Sultana Mar-Yam


    Full Text Available Due to their simplicity and low operation cost, constructed wetlands are becoming more prevalent in wastewater treatment all over the world. Their range of applications is no longer limited to municipal wastewater but has expanded to the treatment of heavily polluted wastewaters such as agro-industrial effluents. This paper provides a comprehensive literature review of the application of constructed wetlands in treating a variety of agro-industrial wastewaters, and discusses pollutant surface loads and the role of constructed wetland type, prior-treatment stages and plant species in pollutant removal efficiency. Results indicate that constructed wetlands can tolerate high pollutant loads and toxic substances without losing their removal ability, thus these systems are very effective bio-reactors even in hostile environments. Additionally, the review outlines issues that could improve pollutant treatment efficiency and proposes design and operation suggestions such as suitable vegetation, porous media and constructed wetland plain view. Finally, a decision tree for designing constructed wetlands treating agro-industrial wastewaters provides an initial design tool for scientists and engineers.

  6. Examination of oxygen release from plants in constructed wetlands in different stages of wetland plant life cycle. (United States)

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


    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.

  7. Effect of polyaluminium chloride on phosphorus removal in constructed wetlands treated with swine wastewater. (United States)

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


    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.

  8. Indicator pathogens, organic matter and LAS detergent removal from wastewater by constructed subsurface wetlands (United States)


    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

  9. Nitrate removal from groundwater using constructed wetlands under various hydraulic loading rates. (United States)

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan; Chang, Yih-Feng; Shih, Kai-Chung


    This study set up two flow-through pilot-scale constructed wetlands with the same size but various flow patterns (free water surface flow (FWS) and subsurface flow (SSF)) to receive a nitrate-contaminated groundwater. The effects of hydraulic loading rate (HLR) on nitrate removal as well as the difference in performance between the various types of wetlands were investigated. Nitrate removal rates of both wetlands increased with increasing HLR until a maximum value was reached. The maximum removal rates, occurred at HLR of 0.12 and 0.07 m d(-1), were 0.910 and 1.161 g N m(-2)d(-1) for the FWS and SSF wetland, respectively. After the maximum values were reached, further increasing HLR led to a considerable decrease in nitrate removal rate. Nitrate removal efficiencies remained high (>85%) and effluent nitrate concentrations always satisfied drinking water standard (NO3-NL(-1)) when HLR did not exceed 0.04 m d(-1) for both FWS and SSF wetlands. The first-order nitrate removal rate constant tends to decrease with increasing HLRs. The FWS wetland provided significantly higher (pwetland, while the SSF wetland exhibited significantly (pwetland. However, there was no significant difference (p>0.05) in nitrate removal performance between the two types of constructed wetlands in this study except in one trial operating at HLR of 0.06-0.07 m d(-1).

  10. Subsurface Treatment of Domestic Wastewater Using Single Domicile Constructed Wetlands (United States)

    Aseltyne, T.; Steer, D.; Fraser, L.


    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.

  11. Influence of environmental variables on the structure and composition of soil bacterial communities in natural and constructed wetlands. (United States)

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


    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Improvement of Groundwater Quality Using Constructed Wetland for Agricultural Irrigation

    Directory of Open Access Journals (Sweden)

    Pantip Klomjek


    Full Text Available This research was designed to evaluate the performance of Constructed Wetlands (CW for groundwater quality improvement. In the first phase of this study, performance of CW planted with cattails for Manganese (Mn and Iron (Fe reduction was evaluated at 12, 24 and 48 hours of Hydraulic Retention Time (HRT. Average efficiencies of all tested CW systems were higher than 90 and 75% for Mn and Fe concentration reduction. Subsequently, the efficiency of CW operated at 12 hours of HRT was investigated at different plant harvest intervals. In the second phase of study, Mn and Fe removal efficiencies were 75-100 and 48-99%, respectively. Both Mn and Fe removal efficiencies for the CW system were not different between 4, 6 and 8 weeks of harvest intervals. However, the efficiency obviously increased after the first plant harvest. Average Mn and Fe removal rates of the CWs operated at the tested harvest intervals were 0.068 to 0.092 and 0.383 to 0.432 g/m2/d, respectively. Fe removal rate was not significantly different under the various test conditions. However the highest Mn removal rate was obtained in CWs operated with a harvest interval of 4 weeks. Mn accumulation rates in cattail shoots and roots were 0.04-8.25 and 0.83-23.14 mg/m2/d, respectively. Fe accumulation rates in those were 0.04-164.27 and 249.62-1,701.54 mg/m2/d, respectively. Obviously, cattail underground tissues accumulated both Mn and Fe at higher concentrations than those of the above ground tissue. These results show that CW can improve the quality of groundwater before agricultural irrigation.

  13. Slag columns for upgrading phosphorus removal from constructed wetland effluents. (United States)

    Chazarenc, F; Brisson, J; Comeau, Y


    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.

  14. Supporting constructed wetlands in P removal efficiency from surface water. (United States)

    Bus, Agnieszka; Karczmarczyk, Agnieszka


    The research investigated the implementation of suspended reactive filters to support the phosphorus (P) removal efficiency of constructed wetlands (CWs). The reactive material (RM) used in this study was autoclaved aerated concrete (AAC). The laboratory experiment consists of four plastic boxes filled with the volume of 10 L of artificial P solution with three variants of RM mass to volume ratio: 1:1 (g:L), 5:1 (g:L), 10:1 (g:L), and the blind probe 0:1 (g:L) as a reference. AAC of different weights (10, 50 and 100 g) was wrapped in a filter bag, put into boxes, and suspended. After 30 days of the laboratory experiment, AAC was able to reduce the P-PO4 concentration from 2.972 mg·L-1 to: 0.341 mgPO4-P·L-1, 0.006 mgPO4-P·L-1 and 0.004 mgPO4-P·L-1 for 10 g, 50 g and 100 g mass variant, respectively. This concentration reduction corresponds to unit sorption of: 2.53 mgP-PO4·g-1, 0.58 mgP-PO4·g-1 and 0.30 mgP-PO4·g-1 for 10 g, 50 g and 100 g, respectively. Based on the obtained data, the CW supporting filter was dimensioned to reduce the outflow P concentration to 0.01 mg·L-1. P removal efficiency prediction was calculated for Cetynia River, Poland.

  15. A smart market for nutrient credit trading to incentivize wetland construction (United States)

    Raffensperger, John F.; Prabodanie, R. A. Ranga; Kostel, Jill A.


    Nutrient trading and constructed wetlands are widely discussed solutions to reduce nutrient pollution. Nutrient markets usually include agricultural nonpoint sources and municipal and industrial point sources, but these markets rarely include investors who construct wetlands to sell nutrient reduction credits. We propose a new market design for trading nutrient credits, with both point source and non-point source traders, explicitly incorporating the option of landowners to build nutrient removal wetlands. The proposed trading program is designed as a smart market with centralized clearing, done with an optimization. The market design addresses the varying impacts of runoff over space and time, and the lumpiness of wetland investments. We simulated the market for the Big Bureau Creek watershed in north-central Illinois. We found that the proposed smart market would incentivize wetland construction by assuring reasonable payments for the ecosystem services provided. The proposed market mechanism selects wetland locations strategically taking into account both the cost and nutrient removal efficiencies. The centralized market produces locational prices that would incentivize farmers to reduce nutrients, which is voluntary. As we illustrate, wetland builders' participation in nutrient trading would enable the point sources and environmental organizations to buy low cost nutrient credits.

  16. Patterns of development and abnormalities among tadpoles in a constructed wetland receiving treated wastewater. (United States)

    Ruiz, Alina M; Maerz, John C; Davis, Andrew K; Keel, M Kevin; Ferreira, Andrew R; Conroy, Michael J; Morris, Lawrence A; Fisk, Aaron T


    Constructed wetlands are promoted for effectiveness at treating wastewater and potential value as wildlife habitat; however, wildlife performance studies in treated wastewater wetlands are limited. We used repeated surveys of larval amphibians along three wetland systems and four reference sites to test the hypothesis that bullfrog tadpoles exposed to direct inputs of treated wastewater develop slower, show a higher frequency of abnormalities, and are smaller at metamorphosis compared to tadpoles from reference ponds. Bullfrog tadpoles from wastewater wetlands were similar in size at metamorphosis compared to tadpoles from reference sites; however, they did show a much higher frequency of abnormalities including severe edema, scoliosis, and extreme calcinosis of soft tissues. Calcinosis was novel to the literature on amphibian abnormalities, the most frequent abnormality, and restricted exclusively to treatment wetlands. Within the constructed wetlands, tadpole development was slower and the frequency of scoliosis and calcinosis was higher in those cells receiving direct inputs of treated wastewater. Our results suggest that portions of constructed wetlands that directly receive treated wastewater may be poor amphibian habitat.

  17. Simultaneous removal of nitrate and sulfate from greenhouse wastewater by constructed wetlands. (United States)

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


    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. Copyright © by the American Society of Agronomy, Crop

  18. The performance of constructed wetlands for, wastewater treatment: a case study of Splash wetland in Nairobi Kenya (United States)

    Nzengy'a, Daniel Muasya; Wishitemi, B. E. L.


    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

  19. [Effect of the subsurface constructed wetland evolution into free surface flow constructed wetland on the removal of organic matter, nitrogen, and phosphor in wastewater]. (United States)

    Wei, Ze-Jun; Xie, Jian-Ping; Huang, Yu-Ming


    Many previous studies demonstrated that the performance of the subsurface constructed wetlands (SSCW) for wastewater treatment was superior to that of the free flow surface constructed wetlands (FFSCW). However, our results indicated that the performance of FFSCW derived from the evolution of SSCW due to clogging for COD, TOC, total nitrogen (TN), and total phosphor (TP) removal was higher than those of SSCW with the same substrate and plant. The laboratory culture experiments were adopted to evaluate the effect of the constructed wetland evolution on the organic matter mineralization, nitrification/denitrification as well as removal of nitrogen and phosphor. It was shown that, after evolution of SSCW into FFSCW, the mineralization rate for organic matter (as TOC) was 1.82 mg x h(-1), and it was 1.49 mg x h(-1) for SSCW. The removal efficiency for NO3(-) was 96.8%, and it was 58.1% for SSCW. The abiotic denitrification removal efficiency was 40%, and it was 28.2% for SSCW. In addition, the maximum equilibrium adsorption capacity of the substrate after evolution for phosphor (as P) was 160 mg x kg(-1), and it was 140 mg x kg(-1) for SSCW substrate. The organic coverage of the substrate was found to be beneficial to phosphor removal. The nitrification ability decreased after evolution. These results suggest the important effect of constructed wetland evolution on its performance.

  20. Investigation of denitrification rates in an ammonia-dominated constructed wastewater treatment wetland (United States)

    Smith, Lesley K.; Sartoris, J.J.; Thullen, J.S.; Andersen, D.C.


    Denitrification measurements were made under simulated field conditions using sediment cores and water collected from the Hemet/San Jacinto Multipurpose Demonstration Wetland (Riverside County, California, USA). The 9.9 ha constructed wetland is used to both polish ammonia-dominated secondary municipal effluent and provide migratory bird habitat. The wetland was originally constructed as a marsh-pond-marsh system in 1994. Over the period from January through March 1998, measured denitrification rates averaged 20.9 ± 20.9 μmol N m−2 h−1 within the emergent marsh portions of the wetland and 646 ± 353 μmol N m−2 h−1 in open water areas. The mean areal denitrification removal rate for this period was 0.70 kg N ha−1 d−1, which accounted for about 8% of the total N removed by the wetland. Internal retention was the main N-removal mechanism. Synoptic water quality surveys indicated that denitrification was limited by a lack of nitrification within the wetland. Between April 1998 and January 1999, the wetland was reconfigured as a hemi-marsh system, having equal areas of interspersed emergent marsh and deep open water. In May 1999, measured denitrification rates averaged 1414 ± 298 μmol N m−2 h−1 within the emergent marsh zones and 682 ± 218 μmol N m−2 h−1 in the open water areas. The mean areal denitrification removal rate was 3.58 kg N ha−1 d−1, which accounted for 40% of the total N removed by the wetland. A synoptic water quality survey indicated that nitrification within the wetland had been enhanced by the reduction of emergent macrophyte biomass and the increase in the area of interspersed deep open water. The modifications to the wetland shifted the nitrogen balance from a large internal storage component and a small denitrification component in 1998 to a more denitrifying system in 1999.

  1. The use of Bassia indica for salt phytoremediation in constructed wetlands. (United States)

    Shelef, Oren; Gross, Amit; Rachmilevitch, Shimon


    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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

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    Asghar Ebrahimi


    Full Text Available 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, –N, –N, and –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 –N in comparison with W2 wetland.

  3. Efficiency of Constructed Wetland Vegetated with Cyperus alternifolius Applied for Municipal Wastewater Treatment (United States)

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


    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

  4. Efficiency of constructed wetland vegetated with Cyperus alternifolius applied for municipal wastewater treatment. (United States)

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


    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.

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

    Collison, R S; Grismer, M E


    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. Susceptibility of constructed wetland microbial communities to silver nanoparticles: A microcosm study


    Button, Mark; Auvinen, Hannele; Van Koetsem, Frederik; Hosseinkhani, Baharak; Rousseau, Diederik; Weber, Kela P.; Du Laing, Gijs


    Silver nanoparticles (AgNPs) are increasingly used as an antimicrobial agent in various consumer products. Silver release from these products occurs during use, washing and disposal at varying rates, into the wastewater system and eventually into aquatic ecosystems. Constructed wetlands (wetlands designed for water pollution control) represent a unique type of water treatment system which are beginning to receive growing amounts of influent AgNP loadings. In order to examine potential impacts...

  7. Constructed Wetlands for Agricultural Wastewater Treatment in Northeastern North America: A Review


    Eric R. Rozema; Andrew C. VanderZaag; Jeff D. Wood; Aleksandra Drizo; Youbin Zheng; Ali Madani; Gordon, Robert J.


    Constructed wetlands (CW) are a treatment option for agricultural wastewater. Their ability to adequately function in cold climates continues to be evaluated as they are biologically active systems that depend on microbial and plant activity. In order to assess their performance and to highlight regional specific design considerations, a review of CWs in Eastern Canada and the Northeastern USA was conducted. Here, we synthesize performance data from 21 studies, in which 25 full-scale wetlands...

  8. Environmental effect of constructed wetland as biofuel production system (United States)

    Liu, Dong


    Being as a renewable energy, biofuel has attracted worldwide attention. Clean biofuel production is an effective way to mitigate global climate change and energy crisis. Biofuel may offer a promising alternative to fossil fuels, but serious concerns arise about the adverse greenhouse gas consequences from using nitrogen fertilizers. Waste-nitrogen recycling is an attractive idea. Here we advocate a win-win approach to biofuel production which takes advantage of excessive nitrogen in domestic wastewater treated via constructed wetland (CW) in China. This study will carry on environmental effect analysis of CW as a biomass generation system through field surveys and controllable simulated experiments. This study intends to evaluate net energy balance, net greenhouse effect potential and ecosystem service of CW as biomass generation system, and make comparation with traditional wastewater treatment plant and other biofuel production systems. This study can provide a innovation mode in order to solve the dilemma between energy crops competed crops on production land and excessive nitrogen fertilizer of our traditional energy plant production. Data both from our experimental CWs in China and other researches on comparable CWs worldwide showed that the biomass energy yield of CWs can reach 182.3 GJ ha-1 yr-1, which was two to eight times higher than current biofuel-production systems. Energy output from CW was ˜137% greater than energy input for biofuel production. If CWs are designed with specific goal of biofuel production, biofuel production can be greatly enhanced through the optimization of N supply, hydraulic structures, and species selection in CWs. Assuming that 2.0 Tg (1 Tg = 1012 g) waste nitrogen contained in domestic wastewater is treated by CWs, biofuel production can account for 1.2% of national gasoline consumption in China. The proportion would increase to 6.7% if extra nitrogen (9.5 Tg) from industrial wastewater and agricultural runoff was included

  9. Constructed wetlands treating highway runoff in the central Mediterranean region. (United States)

    Terzakis, S; Fountoulakis, M S; Georgaki, I; Albantakis, D; Sabathianakis, I; Karathanasis, A D; Kalogerakis, N; Manios, T


    Two free water surface (FWS) and two subsurface flow (SSF) pilot-size constructed wetlands treating highway runoff (HRO) were monitored over a period of two years (September 2005-August 2007). One FWS and one SSF were designed with a hydraulic retention time (HRT) of 12h, named FWS12 and SSF12, respectively, with each one capable of treating a maximum HRO of 12.6 m(3) d(-1). The other couple, named FWS24 and SSF24, respectively, was designed with an HRT of 24h, with each receiving a maximum HRO of 6.3 m(3) d(-1). The influent flowed from a highway section with a total surface 2752 m(2) on the island of Crete, Greece, in the heart of the South-Central Mediterranean region. Influent and effluent were monitored for COD, TSS, total N (TN), NO(3)(-) and total P (TP) concentrations. Furthermore, removal efficiencies were examined for heavy metals (Cu, Ni, Pb, Zn) for both years, while polycyclic aromatic compounds (PAHs) were examined for the period between September 2006 and August 2007. The influent had a two-year average COD value of 101 mg l(-1), whereas the mean values for TSS, TN, N-NO(3)(-) and TP were 203, 4.30, 1.25 and 4.17 mg l(-1), respectively. For Cu, Ni, Pb and Zn the respective two-year mean influent concentrations were 56, 114, 49 and 250 microg l(-1). Mean concentration of total PAHs in runoff (summation operator PAHs, 16 compounds) were 12.01 microg l(-1). The performance among the four beds was not significantly different according to ANOVA analysis followed by Tukey test (at p<0.05) for almost all the above physicochemical parameters, suggesting that all systems performed in a similar way. All studied systems, achieved a mean of two-year removal efficiencies of 47% for COD, 89% for TSS, 49% for TN, 58% for N-NO(3)(-), 60% for TP, 47% for Cu, 23% for Ni, 33% for Pb, 61% for Zn and 59% for summation operator PAHs (16 compounds).

  10. Sustainability of a constructed wetland faced with a depredation event. (United States)

    Maine, M A; Hadad, H R; Sánchez, G C; Mufarrege, M M; Di Luca, G A; Caffaratti, S E; Pedro, M C


    A free water surface constructed wetland (CW) designed for effluent treatment was dominated by the emergent macrophyte Typha domingensis reaching a cover of roughly 80% for 5 years. Highly efficient metal and nutrient removal was reported during this period. In June 2009, a population of approximately 30 capybaras (Hydrochoerus hydrochaeris) caused the complete depredation of the aerial parts of macrophytes. However, plant roots and rhizomes were not damaged. After depredation stopped, T. domingensis showed a luxuriant growth, reaching a cover of 60% in 30 days. The objective of this work was to evaluate the sustainability of the CW subjected to an extreme event. Removal efficiency of the system was compared during normal operation, during the depredation event and over the subsequent recovery period. The CW efficiently retained contaminants during all the periods studied. However, the best efficiencies were registered during the normal operation period. There were no significant differences between the performances of the CW over the last two periods, except for BOD. The mean removal percentages during normal operation/depredation event/recovery period, were: 84.9/73.2/74.7% Cr; 66.7/48.0/51.2% Ni; 97.2/91.0/89.4% Fe; 50.0/46.8/49.5% Zn; 81.0/84.0/80.4% NO3(-); 98.4/93.4/84.1% NO2(-); 73.9/28.2/53.2% BOD and 75.4/40.9/44.6% COD. SRP and TP presented low removal efficiencies. Despite the anoxic conditions, contaminants were not released from sediment, accumulating in fractions that proved to be stable faced with changes in the operating conditions of the CW. T. domingensis showed an excellent growth response, consequently the period without aerial parts lasted a few months and the CW could recover its normal operation. Plants continued retaining contaminants in their roots and the sediment increased its retention capacity, balancing the operating capacity of the system. This was probably due to the fact that the CW had reached its maturity, with a complete root

  11. Sanitation in constructed wetlands: A review on the removal of human pathogens and fecal indicators. (United States)

    Wu, Shubiao; Carvalho, Pedro N; Müller, Jochen A; Manoj, Valsa Remony; Dong, Renjie


    Removal of human pathogens from wastewater is a critical factor with linkage to human health. Constructed Wetlands (CWs) are environmental friendly ecosystems that are applicable not only for chemical pollution control, but also for the reduction of pathogens from wastewater. Yet the knowledge on the fate and removal of such indicator bacteria in CWs is still not sufficient due to the complexity of removal mechanisms and influencing factors. This review serves to provide a better understanding of this state-of-the-art technology, which is necessary for further investigations and design development. The fecal indicator bacteria in CWs mainly come from three sources, namely, influent wastewaters, regrowth within the CWs, and animal activities. The properties of microbial contamination vary depending on the different sources. The removal of pathogens is a complex process that is influenced by operational parameters such as hydraulic regime and retention time, vegetation, seasonal fluctuation, and water composition. The most frequent and well-validated removal mechanisms include natural die-off due to starvation or predation, sedimentation and filtration, and adsorption. The concentration of the main fecal indicator bacteria in the effluent was found to be exponentially related to the loading rate. Generally, horizontal subsurface flow CWs have better reduction capacity than free water surface flow CWs, and hybrid wetland systems were found to be the most efficient due to a longer retention time. Further improvement of fecal indicator bacteria removal in CWs is needed, however, levels in CW effluents are still higher than most of the regulation standards for reuse. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Constructed wetlands for domestic wastewater treatment in a Mediterranean climate region in Chile


    Mancilla Villalobos,Rodrigo; Zúñiga,Jimena; Salgado,Eduardo; Schiappacasse,Maria Cristina; Chamy Maggi,Rolando


    Background: Constructed wetlands are a promising, cheap and effective wastewater treatment in small communities. The studies on these systems have been reported mainly from cold, tropical or subtropical climate regions. In this work we constructed a pilot plant with six horizontal subsurface flow constructed wetlands (HSSF CWs) with a surface area of 2 m² and a depth of 0.6 m each, planted with Typha latifolia or Scirpus sp., and filled with gravel (G) or fine gravel (FG) of 2.8 and 1.2 cm of...

  13. Performance of pilot-scale vertical flow constructed wetlands with and without the emergent macrophyte Spartina alterniflora treating mariculture effluent

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    Wilson Treger Zydowicz Sousa


    Full Text Available Vertical flow constructed wetlands, planted with and without Spartina alterniflora, were tested for the treatment of mariculture wastewater. Wetlands with and without the emergent macrophyte produced reductions of 89 and 71% for inorganic solids, 82 and 96% for organic solids, 51 and 63% for total nitrogen, 82 and 92% for ammoniacal nitrogen, 64 and 59% for orthophosphate, and 81 and 89% for turbidity, respectively. Wetlands with S. alterniflora showed denitrification tendencies, while wetlands without S. alterniflora had higher oxygen levels leading to nitrification. The results suggest the fundamental role of oxygen controlling the purification processes as well as the potential of constructed wetlands to treat mariculture effluents.

  14. 'Halophyte filters': the potential of constructed wetlands for application in saline aquaculture. (United States)

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


    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.

  15. Quantification of herbicide removal in a constructed wetland using passive samplers and composite water quality monitoring. (United States)

    Page, Declan; Dillon, Peter; Mueller, Jochen; Bartkow, Michael


    Constructed wetlands used as treatment for urban stormwater have the potential to improve water quality. This study aimed to estimate the removal of selected herbicides in stormwater by a constructed wetland using composite water quality monitoring and passive samplers. For the four week duration of the study the wetland was effective in reducing the concentrations of diuron, simazine and atrazine. Mean estimated concentrations over a 28 d period were 192, 70 and 5 ng L(-1) at the inlet and 94, 30 and 2 ng L(-1) at the outlet for diuron, simazine and atrazine, respectively. Concentrations of these herbicides generally halved as a result of passage through the constructed wetland with a design hydraulic retention time of 7d. Simple ratios of the inlet and outlet herbicide concentrations as well as hydraulic load-based methods of measuring the wetland's removal efficiency resulted in a range of estimations 33-51% for diuron and 20-60% for simazine. Due to their lower detection limits, the use of passive samplers provides a more efficient technique than conventional sampling for assessment of stormwater wetland treatment. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

  16. Constructed Wetlands for Treatment of Combined Sewer Overflow in the US: A Review of Design Challenges and Application Status

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    Wendong Tao


    Full Text Available As combined sewer systems and centralized wastewater treatment facilities age, many communities in the world are challenged by management of combined sewer overflow (CSO. Constructed wetlands are considered to be one of the green infrastructure solutions to CSOs in the US. Despite the wide application of constructed wetlands to different types of wastewaters, the stochastic and intermittent nature of CSO presents challenges for design and performance assessment of constructed wetlands. This paper reviews the application status of CSO constructed wetlands in the US, assesses the benefits of CSO constructed wetlands, identifies challenges to designing CSO constructed wetlands, and proposes design considerations. This review finds that constructed wetlands are effective in CSO treatment and relatively less expensive to build than comparable grey infrastructure. Constructed wetlands not only remove pollutants, but also mitigate the event-associated flow regime. The design challenges include incorporating considerations of green infrastructure into permit requirements, determining design capacity for highly variable flows, requiring pretreatment, and needing adaptive design and intensive monitoring. Simultaneous monitoring of flow rate and water quality at both the inflow and outflow of CSO constructed wetlands is required for performance assessment and needed to support design, but is rarely available.

  17. Penurunan Logam Timbal (Pb) pada Limbah Cair TPA Piyungan Yogyakarta dengan Constructed Wetlands Menggunakan Tumbuhan Eceng Gondok (Eichornia Crassipes)

    National Research Council Canada - National Science Library

    Siswoyo, Eko; Kasam, Ir; Abdullah, L.M. Subhan

    ...) yang terdapat dalam limbah cair TPA Piyungan dengan Constructed Wetlands menggunakan tumbuhan eceng gondok dan untuk mengetahui seberapa besar kapasitas serapan tumbuhan eceng gondok terhadap kandungan Timbal (Pb...


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    Gražina Žibienė


    Full Text Available Different kinds of natural and artificial filter media are able to retain phosphorus in the constructed wetlands. Due to the fact that the constructed wetland needs huge amounts of the filter media, it is very important to find locally available material which distinguishes itself by its ability to retain phosphorus. The materials found in Lithuania were considered and dolomite was chosen. Two dolomite fractions, dolomite powder (1–2 mm and dolomite chippings (2–5 mm, and sand media were used in the laboratory- scale installed for the comparative experiments. The laboratory-scale with dolomite as the filter media was on average by 21% more efficient in total phosphorus removal in comparison with the sand media. Based on the laboratory research pilot–scale vertical flow constructed wetland of 160 m2 was installed and planted with reed Phragmites australis. The dolomite chippings as filter media were chosen in order to avoid the danger of the clogging of constructed wetland. Efficiency of total phosphorus removal in the pilot-scale vertical flow constructed wetland was on average 95.7%, phosphates removal – 94.8% within one year.

  19. Effects of a constructed wetland and pond system upon shallow groundwater quality (United States)

    Ying Ouyang


    Constructed wetland (CW) and constructed pond (CP) are commonly utilized for removal of excess nutrients and certain pollutants from stormwater. This study characterized shallow groundwater quality for pre- and post-CW and CP system conditions using data from monitoring wells. Results showed that the average concentrations of groundwater phosphorus (P) decreased from...

  20. Iron and manganese removal by using manganese ore constructed wetlands in the reclamation of steel wastewater. (United States)

    Xu, Jing-Cheng; Chen, Gu; Huang, Xiang-Feng; Li, Guang-Ming; Liu, Jia; Yang, Na; Gao, Sai-Nan


    To reclaim treated steel wastewater as cooling water, manganese ore constructed wetland was proposed in this study for the removal of iron and manganese. In lab-scale wetlands, the performance of manganese ore wetland was found to be more stable and excellent than that of conventional gravel constructed wetland. The iron and manganese concentration in the former was below 0.05 mg/L at hydraulic retention time of 2-5 days when their influent concentrations were in the range of 0.16-2.24 mg/L and 0.11-2.23 mg/L, respectively. Moreover, its removals for COD, turbidity, ammonia nitrogen and total phosphorus were 55%, 90%, 67% and 93%, respectively, superior to the corresponding removals in the gravel wetland (31%, 86%, 58% and 78%, respectively). The good performance of manganese ore was ascribed to the enhanced biological manganese removal with the aid of manganese oxide surface and the smaller size of the medium. The presence of biological manganese oxidation was proven by the facts of good manganese removal in wetlands at chemical unfavorable conditions (such as ORP and pH) and the isolation of manganese oxidizing strains from the wetlands. Similar iron and manganese removal was later observed in a pilot-scale gravel-manganese-ore constructed wetland, even though the manganese ore portion in total volume was reduced from 100% (in the lab-scale) to only 4% (in the pilot-scale) for the sake of cost-saving. The quality of the polished wastewater not only satisfied the requirement for cooling water but also suitable as make-up water for other purposes.

  1. An assessment of potential hydrologic and ecologic impacts of constructing mitigation wetlands, Rifle, Colorado, UMTRA project sites

    Energy Technology Data Exchange (ETDEWEB)



    This-assessment examines the consequences and risks that could result from the proposed construction of mitigation wetlands at the New and Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) Project sites near Rifle, Colorado. Remediation of surface contamination at those sites is now under way. Preexisting wetlands at or near the Old and New Rifle sites have been cleaned up, resulting in the loss of 0.7 and 10.5 wetland acres (ac) (0.28 and 4.2 hectares [ha]) respectively. Another 9.9 ac (4.0 ha) of wetlands are in the area of windblown contamination west of the New Rifle site. The US Army Corps of Engineers (USACE) has jurisdiction over the remediated wetlands. Before remedial action began, and before any wetlands were eliminated, the USACE issued a Section 404 Permit that included a mitigation plan for the wetlands to be lost. The mitigation plan calls for 34.2 ac (1 3.8 ha) of wetlands to be constructed at the south end and to the west of the New Rifle site. The mitigation wetlands would be constructed over and in the contaminated alluvial aquifer at the New Rifle site. As a result of the hydrologic characteristics of this aquifer, contaminated ground water would be expected to enter the environment through the proposed wetlands. A preliminary assessment was therefore required to assess any potential ecological risks associated with constructing the mitigation wetlands at the proposed location.


    Directory of Open Access Journals (Sweden)



    Full Text Available The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7 containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and the presence of Phragmites australis had a significant impact on the removal of organic matters, AO7, aromatic amines and NH4-N. The COD removal efficiency in the aerated and non-aerated wetland reactors was 95 and 62%, respectively. The NH4-N removal efficiency in the aerated wetland reactor (86% was significantly higher than the non-aerated wetland reactor (14 %. All wetland reactors show high removal efficiency of AO7 (> 94% but only the aerated wetland reactor perform better in the removal of aromatic amines.

  3. Development of constructed wetlands in performance intensifications for wastewater treatment: a nitrogen and organic matter targeted review. (United States)

    Wu, Shubiao; Kuschk, Peter; Brix, Hans; Vymazal, Jan; Dong, Renjie


    The knowledge on the performance enhancement of nitrogen and organic matter in the expanded constructed wetlands (CWs) with various new designs, configurations, and technology combinations are still not sufficiently summarized. A comprehensive review is accordingly necessary for better understanding of this state-of-the-art-technology for optimum design and new ideas. Considering that the prevailing redox conditions in CWs have a strong effect on removal mechanisms and highly depend on wetland designs and operations, this paper reviews different operation strategies (recirculation, aeration, tidal operation, flow direction reciprocation, and earthworm integration), innovative designs, and configurations (circular-flow corridor wetlands, towery hybrid CWs, baffled subsurface CWs) for the intensifications of the performance. Some new combinations of CWs with technologies in other field for wastewater treatment, such as microbial fuel cell, are also discussed. To improve biofilm development, the selection and utilization of some specific substrates are summarized. Finally, we review the advances in electron donor supply to enhance low C/N wastewater treatment and in thermal insulation against low temperature to maintain CWs running in the cold areas. This paper aims to provide and inspire some new ideas in the development of intensified CWs mainly for the removal of nitrogen and organic matter. The stability and sustainability of these technologies should be further qualified. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Application of constructed wetlands for wastewater treatment in developing countries--a review of recent developments (2000-2013). (United States)

    Zhang, Dong Qing; Jinadasa, K B S N; Gersberg, Richard M; Liu, Yu; Ng, Wun Jern; Tan, Soon Keat


    Inadequate access to clean water and sanitation has become one of the most pervasive problems afflicting people throughout the developing world. Replication of centralized water-, energy- and cost-intensive technologies has proved ineffective in resolving the complex water-related problems resulting from rapid urbanization in the developing countries. Instead constructed wetlands (CWs) have emerged and become a viable option for wastewater treatment, and are currently being recognized as attractive alternatives to conventional wastewater treatment methods. The primary objective of this review is to present a comprehensive overview of the diverse range of practice, applications and researches of CW systems for removing various contaminants from wastewater in developing countries, placing them in the overall context of the need for low-cost and sustainable wastewater treatment systems. Emphasis of this review is placed on the treatment performance of various types of CWs including: (i) free water surface flow CW; (ii) subsurface flow CW; (iii) hybrid systems; and, (iv) floating treatment wetland. The impacts of different wetland design and pertinent operational variables (e.g., hydraulic loading rate, vegetation species, physical configurations, and seasonal variation) on contaminant removal in CW systems are also summarized and highlighted. Finally, the cost and land requirements for CW systems are critically evaluated. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Treatment of table olive washing water using trickling filters, constructed wetlands and electrooxidation. (United States)

    Tatoulis, Triantafyllos; Stefanakis, Alexandros; Frontistis, Zacharias; Akratos, Christos S; Tekerlekopoulou, Athanasia G; Mantzavinos, Dionissios; Vayenas, Dimitrios V


    The production of table olives is a significant economic activity in Mediterranean countries. Table olive processing generates large volumes of rinsing water that are characterized by high organic matter and phenol contents. Due to these characteristics, a combination of more than one technology is imperative to ensure efficient treatment with low operational cost. Previously, biological filters were combined with electrooxidation to treat table olive washing water. Although this combination was successful in reducing pollutant loads, its cost could be further reduced. Constructed wetlands could be an eligible treatment method for integrated table olive washing water treatment as they have proved tolerant to high organic matter and phenol loads. Two pilot-scale horizontal subsurface constructed wetlands, one planted and one unplanted, were combined with a biological filter and electrooxidation over a boron-doped diamond anode to treat table olive washing water. In the biological filter inlet, chemical oxygen demand (COD) concentrations ranged from 5500 to 15,000 mg/L, while mean COD influent concentration in the constructed wetlands was 2800 mg/L. The wetlands proved to be an efficient intermediate treatment stage, since COD removal levels for the planted unit reached 99 % (mean 70 %), while the unplanted unit presented removal rates of around 65 %. Moreover, the concentration of phenols in the effluent was typically below 100 mg/L. The integrated trickling filter-constructed wetland-electrooxidation treatment system examined here could mineralize and decolorize table olive washing water and fully remove its phenolic content.

  6. [Preliminary study on denitrification capacity of constructed wetlands filled by bark]. (United States)

    Jiang, Ying-He; Li, Chao


    Constructed wetlands have been widely used for the treatment of outlets of municipal wastewater treatment plants, treatment of agricultural pollution etc, adequate carbon is a very good source for denitrification and it is very crucial for improving the removal rate of nitrate nitrogen in constructed wetlands. An attempt has been made to workout for the nitrate removal by the integrated vertical constructed wetland, the bark was used for carbon source, the results shows the denitrifying bacteria in the constructed wetlands can utilize the carbon source very well, produced by bark to remove nitrate nitrogen. The efficiency of denitrification increases with the increase of the hydraulic loading and the influent nitrate loading,but the rate of the nitrate nitrogen removal decreases. At the condition of influent NO3(-)-N of 50 mg/L and the hydraulic loading of 0.1 m3/(m2 x d), the removal rate of nitrate nitrogen in the wetland system is around 80%. The suitable pH is 7 to 8 and when the pH is out of this range, it restricts the denitrification process.

  7. Characterization of microbial communities and composition in constructed dairy wetland wastewater effluent. (United States)

    Ibekwe, A Mark; Grieve, Catherine M; Lyon, Stephen R


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

  8. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.-F.; Jing, S.-R.; Lee, D.-Y


    Constructed wetlands improved water qualities and consequently increased the shrimp growth and survival in a recirculating system. - A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD{sub 5}, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO{sub 2}-N, 90%) and nitrate nitrogen (NO{sub 3}-N, 68%). Phosphate (PO{sub 4}-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO{sub 3}-N in the culture tank water in RAS were significantly (P{<=}0.05) lower than those in a control aquaculture system (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (P{<=}0.05) in BOD{sub 5}, TAN and NO{sub 2}-N was found between the two systems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8{+-}1.8 g/shrimp and 90%) significantly (P{<=}0.01) exceeded those in the CAS (2.3{+-}1.5 g/shrimp and 71%). This study concludes that constructed wetlands can improve the water quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system.

  9. Aquatic macroinvertebrates associated with Schoenoplectus litter in a constructed wetland in California (USA) (United States)

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


    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.

  10. Metal distribution and stability in constructed wetland sediment. (United States)

    Knox, Anna Sophia; Paller, Michael H; Nelson, Eric A; Specht, Winona L; Halverson, Nancy V; Gladden, John B


    The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb.

  11. Changes and characteristics of dissolved organic matter in a constructed wetland system using fluorescence spectroscopy. (United States)

    Yao, Yuan; Li, Yun-Zhen; Guo, Xu-Jing; Huang, Tao; Gao, Ping-Ping; Zhang, Ying-Pei; Yuan, Feng


    Domestic wastewater was treated by five constructed wetland beds in series. Dissolved organic matter (DOM) collected from influent and effluent samples from the constructed wetland was investigated using fluorescence spectroscopy combined with fluorescence regional integration (FRI), parallel factor (PARAFAC) analysis, and two-dimensional correlation spectroscopy (2D-COS). This study evaluates the capability of these methods in detecting the spectral characteristics of fluorescent DOM fractions and their changes in constructed wetlands. Fluorescence excitation-emission matrix (EEM) combined with FRI analysis showed that protein-like materials displayed a higher removal ratio compared to humic-like substances. The PARAFAC analysis of wastewater DOM indicated that six fluorescent components, i.e., two protein-like substances (C1 and C6), three humic-like substances (C2, C3 and C5), and one non-humic component (C4), could be identified. Tryptophan-like C1 was the dominant component in the influent DOM. The removal ratios of six fluorescent components (C1-C6) were 56.21, 32.05, 49.19, 39.90, 29.60, and 45.87 %, respectively, after the constructed wetland treatment. Furthermore, 2D-COS demonstrated that the sequencing of spectral changes for fluorescent DOM followed the order 298 nm → 403 nm → 283 nm (310-360 nm) in the constructed wetland, suggesting that the peak at 298 nm is associated with preferential tryptophan fluorescence removal. Variation of the fluorescence index (FI) and the ratio of fluorescence components indicated that the constructed wetland treatment resulted in the decrease of fluorescent organic pollutant with increasing the humification and chemical stability of the DOM.

  12. The influence of urbanisation on macroinvertebrate biodiversity in constructed stormwater wetlands. (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M


    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Analysis of chemical reaction kinetics of depredating organic pollutants from secondary effluent of wastewater treatment plant in constructed wetlands. (United States)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D. (Argonne National Lab., IL (United States)); Rastorfer, J.R. (Chicago State Univ., IL (United States). Dept. of Biological Sciences ANL/CSU Cooperative Herbarium, Chicago, IL (United States)); Van Dyke, G.D. (Trinity Christian Coll., Palos Heights, IL (United States). Dept. of Biology)


    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.

  15. Microbial diversity of bacteria, archaea, and fungi communities in a continuous flow constructed wetland for the treatment of swine waste (United States)

    Contaminant removal in constructed wetlands may largely be a function of many microbial processes. However, information about bacterial, archaea, and fungi communities in constructed wetlands for the removal of swine waste is limited. In this study, we used 454/GS-FLX pyrosequencing to assess bacter...

  16. Inferring energy sources in constructed wetlands through stable isotope analysis of microbial biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Jurkowski, K.; Ciborowski, J. [Windsor Univ., ON (Canada); Daly, C. [Suncor Energy, Fort McMurray, AB (Canada)


    This study presented a novel method of sequestering the microbial biofilm in constructed wetland ecosystems. Artificial substrates were fixed within 8 wetlands differing in age and construction materials over a 2 year period at oil sands lease sites in northeastern Alberta. Autotrophic and heterotrophic biofilm samples were collected from both the subsurface and epibenthic zones of the pipe surfaces of each submerged substrate assembly. A mixing model of d13C, d15N and d34S isotopic signatures was used to assess the contribution of 4 potential nutrient sources of the biofilm. Samples included dominant living and senescent emergent as well as submergent macrophytes, particulate organic matter, dissolved organic carbon, and invertebrates. The samples were collected to compare the biofilm signatures of each wetland in relation to the heterotrophic processes caused by the assimilation of oil sands-derived hydrocarbons and autochthonous detrital pools.

  17. Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons. (United States)

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


    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.

  18. Vertical flow constructed wetlands: kinetics of nutrient and organic matter removal. (United States)

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


    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.

  19. Relationships between Spatial Metrics and Plant Diversity in Constructed Freshwater Wetlands. (United States)

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


    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.

  20. Aquatic macrophytes can be used for wastewater polishing but not for purification in constructed wetlands (United States)

    Tang, Yingying; Harpenslager, Sarah F.; van Kempen, Monique M. L.; Verbaarschot, Evi J. H.; Loeffen, Laury M. J. M.; Roelofs, Jan G. M.; Smolders, Alfons J. P.; Lamers, Leon P. M.


    The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m-2 d-1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥ 21.4 mg P m-2 d-1), 50-90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45-90 % was either taken up by the sediment or lost to the atmosphere at loadings ≥ 62 mg N m-2 d-1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove

  1. Impact of riverine wetlands construction and operation on stream channel stability: Conceptual framework for geomorphic assessment (United States)

    Rhoads, Bruce L.; Miller, Michael V.


    Wetland conservation is a critical environmental management issue. An emerging approach to this issue involves the construction of wetland environments. Because our understanding of wetlands function is incomplete and such projects must be monitored closely because they may have unanticipated impacts on ecological, hydrological, and geomorphological systems. Assessment of project-related impacts on stream channel stability is an important component of riverine wetlands construction and operation because enhanced erosion or deposition associated with unstable rivers can lead to loss of property, reductions in channel capacity, and degradation of water quality, aquatic habitat, and riparian aesthetics. The water/sediment budget concept provides a scientific framework for evaluating the impact of riverine wetlands construction and operation on stream channel stability. This concept is based on the principle of conservation of mass, i.e., the total amount of water and sediment moving through a specific reach of river must be conserved. Long-term measurements of channel sediment storage and other water/sediment budget components provide the basis for distinguishing between project-related impacts and those resulting from other causes. Changes in channel sediment storage that occur as a result of changes in internal inputs of water or sediment signal a project-related impact, whereas those associated with changes in upstream or tributary inputs denote a change in environmental conditions elsewhere in the watershed. A geomorphic assessment program based on the water/sediment budget concept has been implemented at the site of the Des Plaines River Wetlands Demonstration Projection near Chicago, Illinois, USA. Channel sediment storage changed little during the initial construction phase, suggesting that thus far the project has not affected stream channel stability.

  2. The contribution of nitrogen fixation by cyanobacteria to particulate organic nitrogen in a constructed wetland (United States)

    Zhang, X.; PAN, X.; MA, M.; Li, W.; Cui, L.


    N-fixing cyanobacteria can create extra nitrogen for aquatic ecosystems. Previous studies reported inconsistence patterns of the contribution of biological nitrogen fixation to the nitrogen pools in aquatic ecosystems. However, there were few studies concerning the effect of fixed nitrogen by cyanobacteria on the nitrogen removal efficiency in constructed wetlands. This study was performed at the Beijing Wildlife Rescue and Rehabilitation Centre, where a constructed lake for the habitation of waterfowls and a constructed wetland for purifying sewage from the lake are located. The composition of phytoplankton communities, the concentrations of particulate organic nitrogen (PON) and nitrogen fixation rates (Rn) in the constructed lake and the constructed wetland were compared throughout a growing season. We counted the densities of genus Anabaena and Microcystis cells, and explored their relationships with PON and Rn in water. The proportions of PON from various sources, including the ambient N2, waterfowl faeces, wetland sediments and the nitrates, were calculated by the natural abundance of 15N with the IsoSource software. The result revealed that the constructed lake was alternately dominated by Anabaena and Microcystis throughout the growing season, and the Rn was positively correlated with PON and the cell density of Anabaena (P < 0.05). This implied that the fixed nitrogen by N-fixing Anabaena might be utilized by non-N-fixing Microcystis, maintaining the fixed nitrogen with PON form. The ambient N2 composed 0.5 82% and 50.0 84.7% to the PON in the constructed lake and wetland respectively during the growing season. The proportions of PON from N2 increased to more than 80% when the Rn reached the highest in September. The result demonstrated that the nitrogen fixed by Anabaena might be utilized by non-N-fixing Microcystis which formed water blooms in summer. Therefore, the decline of the removal efficiency of PON in the constructed wetland in summer might

  3. Designing and construction of simulated constructed wetland for treatment of sewage containing metals. (United States)

    Upadhyay, A K; Singh, N K; Bankoti, N S; Rai, U N


    A simulated horizontal flow constructed wetland (CW) has been designed with gravel medium and aquatic plants Typha latifolia and Polygonum hydropiper to assess its performance efficiency for sewage treatment. Monitoring of fully developed CW revealed a high removal of nutrients and metals from sewage after treatment at varying retention times. The percent (%) removal of biological oxygen demand, total dissolved solids, total suspended solids, PO4-P and total nitrogen in CW planted with T. latifolia were 88.20, 61.9, 72.12, 74.23 and 66.78%; however, with P. hydropiper, reductions were 79.47, 53.47, 55.46, 60.40 and 52.87%, respectively, at 8 d retention time. In addition, T. latifolia and P. hydropiper accumulated substantial amount of metals in their tissues particularly in roots. T. latifolia root accumulated maximum amount of Zn (40.44 µg/g dw) followed by Cu (39.24 µg/g dw), Pb (37.78 µg/g dw) and Cr (19.95 µg/g dw) as compared to P. hydropiper, which was 17.85, 33.43, 36.19 and 9.67 µg/g dw, respectively. Further, plant-specific high translocation factor (>1) of metals were observed at different retention times. Results suggest that simulated CW may be applied as an ecofriendly and low-cost tool to treat sewage before discharge into a fresh water body.

  4. On-site wastewater treatment using subsurface flow constructed wetlands in Ireland. (United States)

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


    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

  5. Bacterial community dynamics in surface flow constructed wetlands for the treatment of swine waste. (United States)

    Ibekwe, A M; Ma, J; Murinda, Shelton; Reddy, G B


    Constructed wetlands are generally used for the removal of waste from contaminated water. In the swine production system, wastes are traditionally flushed into an anaerobic lagoon which is then sprayed on agricultural fields. However, continuous spraying of lagoon wastewater on fields can lead to high N and P accumulations in soil or lead to runoff which may contaminate surface or ground water with pathogens and nutrients. In this study, continuous marsh constructed wetland was used for the removal of contaminants from swine waste. Using pyrosequencing, we assessed bacterial composition within the wetland using principal coordinate analysis (PCoA) which showed that bacterial composition from manure influent and lagoon water were significantly different (P=0.001) from the storage pond to the final effluent. Canonical correspondence analysis (CCA) showed that different bacterial populations were significantly impacted by ammonium--NH4 (P=0.035), phosphate--PO4(3-) (P=0.010), chemical oxygen demand--COD (P=0.0165), total solids--TS (P=0.030), and dissolved solids--DS (P=0.030) removal, with 54% of the removal rate explained by NH4+PO4(3-) according to a partial CCA. Our results showed that different bacterial groups were responsible for the composition of different wetland nutrients and decomposition process. This may be the major reason why most wetlands are very efficient in waste decomposition. Published by Elsevier B.V.

  6. Suspended particle and pathogen peak discharge buffering by a surface-flow constructed wetland

    NARCIS (Netherlands)

    Mulling, B.T.M.; van den Boomen, R.M.; van der Geest, H.G.; Kappelhof, J.W.N.M.; Admiraal, W.


    Constructed wetlands (CWs) have been shown to improve the water quality of treated wastewater. The capacity of CWs to reduce nutrients, pathogens and organic matter and restore oxygen regime under normal operating conditions cannot be extrapolated to periods of incidental peak discharges. The

  7. Constructed wetlands as green tools for management of boron mine wastewater. (United States)

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


    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.

  8. Chlorobenzene removal efficiencies and removal processes in a pilot-scale constructed wetland treating contaminated groundwater

    DEFF Research Database (Denmark)

    Braeckevelt, M.; Reiche, N.; Trapp, Stefan


    Low-chlorinated benzenes (CBs) are widespread groundwater contaminants and often threaten to contaminate surface waters. Constructed wetlands (CWs) in river floodplains are a promising technology for protecting sensitive surface water bodies from the impact of CBs. The efficiency and seasonal var...

  9. Removal of pharmaceutically active compounds in constructed wetlands: mechanisms and application

    NARCIS (Netherlands)

    He, Yujie


    A constructed wetland (CW) is an integrated and enhanced version of natural ecosystem for fate and transport of pharmaceutically active compounds (PhAC). This thesis demonstrates removal mechanisms of PhACs in CWs and their application as post-treatment processes to eliminate PhACs from wastewater

  10. Water and mass budgets of a vertical-flow constructed wetland used for wastewater treatment

    NARCIS (Netherlands)

    Meuleman, Arthur F M; Van Logtestijn, Richard; Rijs, Gerard B J; Verhoeven, Jos T A

    To estimate the nutrient and organic matter (Biological Oxygen Demand (BODs) and Chemical Oxygen Demand (COD)) removal capacity of a constructed vertical-flow wetland in The Netherlands, a water and nutrient budget study was conducted. Also bacterial water quality enhancement was measured. The

  11. A pilot study on municipal wastewater treatment using a constructed wetland in Uganda

    NARCIS (Netherlands)

    Okurut, T.O.


    The potential of using constructed v wetlands as a cheaper and yet effective alternative method for treating domestic wastewater in tropical environments was investigated in this study from May 1996 - April 1999. The major aim was to determine their technical viability with respect to

  12. Planning and establishment principles for constructed wetlands and riparian buffer zones in agricultural catchments

    NARCIS (Netherlands)

    Mander, Ülo; Tournebize, Julien; Tonderski, Karin; Verhoeven, Jos|info:eu-repo/dai/nl/068425023; Mitsch, William J.


    In a great number of scientific articles on water quality improvement using constructed wetlands (CW) and riparian buffers zones (RBZ) at catchment scale, contradictory results are found. In most cases this is due to underestimating or even ignoring the role of the hydrological factor for water

  13. Greenhouse gas emissions from a constructed wetland - Plants as important sources of carbon

    Czech Academy of Sciences Publication Activity Database

    Picek, T.; Čížková, Hana; Dušek, J.


    Roč. 31, - (2007), s. 98-106 ISSN 0925-8574 R&D Projects: GA ČR GA526/06/0276 Institutional research plan: CEZ:AV0Z60870520 Keywords : Constructed wetland * Carbon dioxine * Methane * Nitrous oxide * Ges emissions Subject RIV: DJ - Water Pollution ; Quality Impact factor: 2.175, year: 2007

  14. Responses of phytoplankton and Hyalella azteca to agrichemical mixtures in a constructed wetland mesocosms (United States)

    We assessed the capability of a constructed wetland to mitigate toxicity of a variety of possible mixtures such as nutrients only (N, P), pesticides only (atrazine, S-metolachlor, permethrin), and nutrients+pesticides on phytoplankton chlorophyll a, 48 h aqueous Hyalella azteca survival, and 10 d se...

  15. Simulating phosphorus removal from a vertical-flow constructed wetland grown with C alternifolius species (United States)

    Ying Ouyang; Lihua Cui; Gary Feng; John Read


    Vertical flow constructed wetland (VFCW) is a promising technique for removal of excess nutrients and certain pollutants from wastewaters. The aim of this study was to develop a STELLA (structural thinking, experiential learning laboratory with animation) model for estimating phosphorus (P) removal in an artificial VFCW (i.e., a substrate column with six zones) grown...

  16. Removal of chlorophenolics from pulp and paper mill wastewater through constructed wetland. (United States)

    Choudhary, Ashutosh Kumar; Kumar, Satish; Sharma, Chhaya


    This study evaluates the treatment efficiency of horizontal subsurface flow (HSSF) constructed wetland for the removal of AOX (adsorbable organic halides) and chlorophenolics from pulp and paper mill wastewater. The dimensions of HSSF constructed wetland were 3.5 m in length, 1.5 m in width, and 0.28 m in depth, with surface area of 5.25 m2. The HSSF constructed wetland unit was planted with an ornamental plant species, Canna indica. Under hydraulic retention time (HRT) of 5.9 days, the average AOX removal was 89.1%, and 67% to 100% removal of chlorophenolics from pulp and paper mill wastewater was achieved. The complete removal of 2,3-dichlorophenol, 3,4-dichlorophenol, 2,3,5-trichlorophenol, 2,4,6-trichlorophenol, 3,5-dichlorocatechol, 3,6-dichlorocatechol, and 4,5,6-trichloroguaiacol was observed. Some of the chlorophenolics were found to accumulate in the plant biomass and soil. The evapotranspiration rate varied from 6.7 to 12.7 mm day(-1) during the experimental period. The mass balance of chlorophenolics was also studied in constructed wetland system.

  17. Physical and biological changes of suspended particles in a free surface flow constructed wetland

    NARCIS (Netherlands)

    Mulling, B.T.M.; van den Boomen, R.M.; Claassen, T.H.L.; van der Geest, H.G.; Kappelhof, J.W.N.M.; Admiraal, W.


    Suspended particles are considered as contaminants in treated wastewater and can have profound effects on the biological, physical and chemical properties of receiving aquatic ecosystems, depending on the concentration, type and nature of the suspended particles. Constructed wetlands are known to

  18. A comparison of charcoal- and slag-based constructed wetlands for ...

    African Journals Online (AJOL)

    Subsurface-flow constructed wetlands (CW) with charcoal- or slag-based bed matrices were investigated for their potential use in remediating acid mine drainage (AMD). A CW is effectively a reactor in which some components of the wastewater are broken down by the organisms occurring within the CW, whilst others may ...

  19. [Effect of design and operation parameters on volatile alkylsulfides removal in subsurface constructed wetlands]. (United States)

    Feng, Lin; Gan, Li; Wang, Hua-jie; Mo, Ping; Huang, Yu-ming


    A pilot-scale subsurface constructed wetland wastewater treatment system was sampled for one year to study the effects of bed aspect ratio, substrate medium size, water depth, HLR (hydraulic loading rate) and temperature (season) on removal of volatile alkylsulfides such as DMS (dimethylsulfide) and DMDS (dimethyldisulfide). The yearly experimental results demonstrated that the system showed good performance for DMS and DMDS removal in wastewater under different HLR ranging from 12 cm x d(-1) to 86 cm x d(-1). The system could remove 86% of DMS, and 95% of DMDS, respectively. ANOVA statistical analysis shows that HLR and temperature (season) are major factors controlling the system performance for the target analytes. According to ANOVA test, the HLR caused significant differences (p 0.05) on the average DMS and DMDS effluent concentrations. A survey of dissolved oxygen and ORP indicates that the constructed wetlands system showed strong reduced condition. On the basis of investigations of electron acceptors (such as SO4(2-), NO3- and NO2-) and dissolved organic pollutants (such as TOC and acetic acid) concentrations along with the length of constructed wetlands, it can be concluded that sulfate reduction and methanogenisis were estimated to be significant for DMS and DMDS removal in constructed wetland beds.

  20. Constructed wetlands for freshwater and saline aquaculture wastewater treatment: a microcosm experience


    Jesus, J.M.; Borges, M. T.; Calheiros, Cristina S.C.; Castro, Paula M.L.


    Poster presentation published at page 185 The aquaculture industry discharges large volumes of nutrient rich wastewater, contributing to eutrophication events. Recent culture intensification methodologies such as recirculation (RAS) and shallow raceway (SRS) systems discharge wastewater with even higher nutrient concentrations, though at lower volumes (Rana et al., 2005). Hence, efluent treatment options are of vital importance. Constructed wetlands (CWs) are a possible but ...

  1. Improved Wetland Classification Using Eight-Band High Resolution Satellite Imagery and a Hybrid Approach

    Directory of Open Access Journals (Sweden)

    Charles R. Lane


    Full Text Available Although remote sensing technology has long been used in wetland inventory and monitoring, the accuracy and detail level of wetland maps derived with moderate resolution imagery and traditional techniques have been limited and often unsatisfactory. We explored and evaluated the utility of a newly launched high-resolution, eight-band satellite system (Worldview-2; WV2 for identifying and classifying freshwater deltaic wetland vegetation and aquatic habitats in the Selenga River Delta of Lake Baikal, Russia, using a hybrid approach and a novel application of Indicator Species Analysis (ISA. We achieved an overall classification accuracy of 86.5% (Kappa coefficient: 0.85 for 22 classes of aquatic and wetland habitats and found that additional metrics, such as the Normalized Difference Vegetation Index and image texture, were valuable for improving the overall classification accuracy and particularly for discriminating among certain habitat classes. Our analysis demonstrated that including WV2’s four spectral bands from parts of the spectrum less commonly used in remote sensing analyses, along with the more traditional bandwidths, contributed to the increase in the overall classification accuracy by ~4% overall, but with considerable increases in our ability to discriminate certain communities. The coastal band improved differentiating open water and aquatic (i.e., vegetated habitats, and the yellow, red-edge, and near-infrared 2 bands improved discrimination among different vegetated aquatic and terrestrial habitats. The use of ISA provided statistical rigor in developing associations between spectral classes and field-based data. Our analyses demonstrated the utility of a hybrid approach and the benefit of additional bands and metrics in providing the first spatially explicit mapping of a large and heterogeneous wetland system.

  2. How efficient are constructed wetlands in removing pharmaceuticals from untreated and treated urban wastewaters? A review. (United States)

    Verlicchi, Paola; Zambello, Elena


    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. © 2013.

  3. Management of Acidic Mine Waste Water by Constructed Wetland Treatment Systems: A Bench Scale Study


    Sheoran, A. S.


    Constructed wetlands have emerged as a viable option for treatment of acidic mine wastewater. Bench scale experiments were conducted, to evaluate the performance of wetland treatment system, with emergent macrophyte Desmostachya bipinnata and substrate (containing powdered goat manure, wood shavings and soil) for 24, 48, 72, 96 and 168 hours of retention period for different water column heights (100mm, 150mm and 200mm). Within 24 hours of retention period the pH increased from 2.93 to 7.22, ...

  4. Statistical Analysis of Nitrogen in the Soil of Constructed Wetland with Horizontal Sub-Surface Flow

    Directory of Open Access Journals (Sweden)

    Jakubaszek Anita


    Full Text Available The removal of nitrogen compounds in constructed wetlands depends on various physical, chemical and biomechanical factors as well as on conditions of the environment. The paper presents the results of a statistical analysis of the depositing of nitrogen at HSSF (horizontal subsurface flow construcred wetland. The results of the substrate showed that the highest contents of nitrogen existed in the surface soil layer up to 20 cm of the depth. Nitrogen accumulation decreased in the deposit with depth, and in the direction of the wastewater flow.





    The objective of present study is to evaluate the using of constructed wetland under semi-batch operation for the treatment of azo dye Acid Orange 7 (AO7) containing wastewater. The emergent plant selected in our study was Phragmites australis. Toxic signs were observed at the Phragmites australis after the addition of AO7 into the wetland reactors but it can adapt to the wastewater as shown in the increase of stem as the operation continue. Our result shows that the artificial aeration and t...

  6. Removal of mercury from gold mine effluents using Limnocharis flava in constructed wetlands. (United States)

    Marrugo-Negrete, José; Enamorado-Montes, Germán; Durango-Hernández, José; Pinedo-Hernández, José; Díez, Sergi


    Phytoremediation has received increased attention over the recent decades, as an emerging and eco-friendly approach that utilizes the natural properties of plants to remediate contaminated water, soils or sediments. The current study provides information about a pilot-scale experiment designed to evaluate the potential of the anchored aquatic plant Limnocharis flava for phytoremediation of water contaminated with mercury (Hg), in a constructed wetland (CW) with horizontal subsurface flow (HSSF). Mine effluent used in this experiment was collected from a gold mining area located at the Alacran mine in Colombia (Hg: 0.11 ± 0.03 μg mL -1 ) and spiked with HgNO 3 (1.50 ± 0.09 μg mL -1 ). Over a 30 day test period, the efficiency of the reduction in the heavy metal concentration in the wetlands, and the relative metal sorption by the L. flava, varied according to the exposure time. The continued rate of removal of Hg from the constructed wetland was 9 times higher than the control, demonstrating a better performance and nearly 90% reduction in Hg concentrations in the contaminated water in the presence of L. flava. The results in this present study show the great potential of the aquatic macrophyte L. flava for phytoremediation of Hg from gold mining effluents in constructed wetlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Qualitative variability in microbial community of constructed wetlands used for purifying wastewater contaminated with pharmaceutical substances. (United States)

    Nowrotek, Monika; Ziembińska-Buczyńska, Aleksandra; Miksch, Korneliusz


    Pharmaceutical substances and their residues are increasingly present in the environment. Therefore, attempts at their removal are made by using different processes. Increasingly important among these processes are those modeled on natural phenomena which occur in wetland ecosystems, called technical scale constructed wetlands. Microbial degradation is an important process in these constructed wetlands. The biodegradation of chemicals often involves a complex series of biochemical reactions and usually varies with the microorganisms involved. The objectives of this study were to determine the impact of sulfamethoxazole and diclofenac on ammonia oxidizing bacteria and other parameters of wastewater in the microcosm of down-flow constructed wetlands. The Spearman correlation coefficient attained negative values in the case of comparison of the Shannon biodiversity index and the parameters of purified wastewater. This dependence was pronounced. In the case of pharmaceutical substances dosed with wastewater, the Spearman correlation coefficient assumed positive values. The highest value assumed by the Spearman correlation coefficient (0.9) was for the removal of diclofenac and Shannon index values for the planted columns, with a very high relationship. For unplanted columns, this value equaled 0.6. For sulfamethoxazole, the value for planted columns was 0.7, and for unplanted -0.7. The presence of plants did not have an impact on the Shannon biodiversity index.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Juan; Feng, Yuqin; Dai, Yanran; Cui, Naxin [State Key Laboratory of Pollution Control and ResourceReuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Anderson, Bruce [Department of Civil Engineering, Queen' s University, Kingston K7L3N6 (Canada); Cheng, Shuiping, E-mail: [State Key Laboratory of Pollution Control and ResourceReuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)


    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{sup −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 (Φ{sub PSII}) 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. - Highlights: • Physiological responses of the wetland plant to triazophos

  9. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands. (United States)

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming


    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Effects of acidification on metal accumulation by aquatic plants and invertebrates. 1. Constructed wetlands (United States)

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


    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.

  11. EPS solubilization treatment by applying the biosurfactant rhamnolipid to reduce clogging in constructed wetlands. (United States)

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


    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Desain IPAL Pengolahan Grey Water dengan Teknologi Subsurface Flow Constructed Wetland di Rusunawa Grudo Surabaya

    Directory of Open Access Journals (Sweden)

    Ahmad Safrodin


    Full Text Available Pencemaran Lingkungan di Kota Surabaya akan terus meningkat  seiring dengan perkembangan penduduk dan keterbatasan sarana sanitasi yang kurang baik. Pencemaran lingkungan ini didominasi limbah domestik sehingga perlu sistem pengolahan yang efektif dan efisien dalam mendegradasi senyawa polutan. Teknologi Constructed wetland merupakan  sistem  pengolahan  terencana atau terkontrol yang telah didesain dan dibangun menggunakan proses alami yang  melibatkan  vegetasi,  media,  dan  mikroorganisme  untuk  mengolah  air  limbah domestik. Teknologi ini dapat diterapkan untuk skala perumahan baik individu atau secara komunal. Rusunawa Grudo Surabaya merupakan rusun yang belum memiliki IPAL untuk mengolah greywater, sehingga sistem Contructed wetland ini dapat diterapkan untuk meningkatkan kualitas sanitasi lingkungan. Perencanaan sistem Constructed wetland di Rusunawa Grudo Surabaya mempertimbangkan aspek kuantitas dan kualitas air limbah. Kualitas air limbah domestik menunjukkan nilai COD 329.81 mg/L; BOD 182.02 mg/L; dan TSS 103.33 mg/L, sedangkan kuantitas air limbah 33.6 m3/hari. Sistem ini terdiri dari unit ekualisasi, Subsurface Flow Constructed Wetland dengan tanaman Cyperus alternifolius, dan kolam penampung. Hasil perencanaan menunjukkan efisiensi pengolahan seluruh sistem untuk COD, BOD, dan TSS masing-masing sebesar 86%, 85%, dan 88%. Desain sistem IPAL menghasilkan luas permukaan 480 m2, kedalaman bed 0,5 m, beban pada bed (OLR 12.75 gr BOD/m2.hari, beban hidrolik (HLR 0,07 m3/m2.hari dengan waktu tinggal 3 hari. Kualitas efluen yang didapatkan menunjukkan nilai BOD 25 mg/L, COD 48.35 mg/L dan TSS 11.72 mg/L. Dihasilkan standar operasional dan perawatan IPAL dan Biaya investasi seluruh sistem constructed wetland diperkirakan sebesar Rp.412.059.022.

  13. The use of constructed wetlands for the treatment of industrial wastewater

    Directory of Open Access Journals (Sweden)

    Skrzypiecbcef Katarzyna


    Full Text Available Constructed wetlands are characterized by specific conditions enabling simultaneous various physical and biochemical processes. This is the result of specific environment for the growth of microorganisms and hydrophytes (aquatic and semiaquatic plants which are capable of living in aerobic, anaerobic and facultative anaerobic conditions. Their interaction contributes to the intensification of oxidation and reduction responsible for the removal and retention of pollutants. These processes are supported by sorption, sedimentation and assimilation. Thanks to these advantages, treatment wetland systems have been used in communal management for over 50 years. In recent years, thanks to its advantages, low operational costs and high removal efficiency, there is growing interest in the use of constructed wetlands for the treatment or pre-treatment of various types of industrial wastewater. The study analyzes current use of these facilities for the treatment of industrial wastewater in the world. The conditions of use and efficiency of pollutants removal from readily and slowly biodegradable wastewater, with special emphasis on specific and characteristic pollutants of particular industries were presented. The use of subsurface horizontal flow beds for the treatment of industrial wastewater, among others from crude oil processing, paper production, food industry including wineries and distillery, olive oil production and coffee processing was described. In Poland constructed wetlands are used for the treatment of sewage and sludge from milk processing in pilot scale or for dewatering of sewage sludge produced in municipal wastewater treatment plant treating domestic sewage with approximately 40% share of wastewater from dairy and fish industry. In all cases, constructed wetlands provided an appropriate level of treatment and in addition the so-called ecosystem service.

  14. The role of constructed wetlands for biomass production within the water-soil-waste nexus. (United States)

    Avellan, C T; Ardakanian, R; Gremillion, P


    The use of constructed wetlands for water pollution control has a long standing tradition in urban, peri-urban, rural, agricultural and mining environments. The capacity of wetland plants to take up nutrients and to filter organic matter has been widely discussed and presented in diverse fora and published in hundreds of articles. In an ever increasingly complex global world, constructed wetlands not only play a role in providing safe sanitation in decentralized settings, shelter for biodiversity, and cleansing of polluted sites, in addition, they produce biomass that can be harvested and used for the production of fodder and fuel. The United Nations University Institute for Integrated Management of Material Fluxes and of Resources (UNU-FLORES) was established in December 2012 in Dresden, Germany, to assess the trade-offs between and among resources when making sustainable decisions. Against the backdrop of the Water-Energy-Food Nexus, which was introduced as a critical element for the discussions on sustainability at Rio +20, the UNU was mandated to pay critical attention to the interconnections of the underlying resources, namely, water, soil and waste. Biomass for human consumption comes in the form of food for direct use, as fodder for livestock, and as semi-woody biomass for fuelling purposes, be it directly for heating and cooking or for the production of biogas and/or biofuel. Given the universal applicability of constructed wetlands in virtually all settings, from arid to tropical, from relatively high to low nutrient loads, and from a vast variety of pollutants, we postulate that the biomass produced in constructed wetlands can be used more extensively in order to enhance the multi-purpose use of these sites.

  15. Wastewater treatment in horizontal subsurface flow constructed wetlands using different media (setup stage

    Directory of Open Access Journals (Sweden)

    Abdel Razik A. Zidan


    Full Text Available Wastewater treatment through horizontal subsurface flow (HSSF constructed wetlands (CWs using three different treatment media (gravel, pieces of plastic pipes, and shredded tire rubber chips were investigated in Samaha village, Dakahliya, Egypt. The study focused on the wetland setup stage during the first months of its operation (setup stage. In this stage media porosity, bacterial biofilm, and plant roots growth were in progress and it was prior to the operational steady state stage. Objectives of this paper are to study the change in media porosity of HSSF wetland cells in order to estimate duration of wetland setup stage, and to evaluate the use of different bed media on biological oxygen demand (BOD, chemical oxygen demand (COD and total suspended solids (TSS treatment. The results showed that after 180 days of operation, the wetland cells had reached steady porosity and had started stable treatment. Also performance of plastic media bed in pollutants reduction was better than gravel and rubber beds and gravel media was in advanced than rubber media.

  16. Vegetation type and layer depth influence nitrite-dependent methane-oxidizing bacteria in constructed wetland. (United States)

    Yang, Mengxi; Guo, Qingwei; Tong, Tianli; Li, Ningning; Xie, Shuguang; Long, Yan


    Nitrite-dependent anaerobic methane oxidation (n-damo) process might be an important methane sink in wetland system. However, information on n-damo microorganisms in constructed wetland (CW) system for water treatment is still lacking. The present study investigated the n-damo communities in five full-scale vertical-flow CW systems with different plants. N-damo bacterial abundance did not show a considerable shift in CW planted with Cyperus papyrus, but varied greatly in other CW systems. However, the evident vertical change of n-damo community diversity occurred in each CW system. These CW systems displayed the different vertical change trends for either n-damo community abundance or diversity. In addition, CW n-damo community structure could change with wetland layer depth. At a given wetland layer depth, the evident difference of n-damo community abundance, diversity and structure could be observed in the five different CW systems. Both wetland layer depth and vegetation type could contribute to the shift of n-damo bacterial abundance and community structure in CWs.

  17. Investigation of nitrogen transformations in a southern California constructed wastewater treatment wetland (United States)

    Sartoris, J.J.; Thullen, J.S.; Barber, L.B.; Salas, D.E.


    A 9.9-ha combined habitat and wastewater treatment demonstration wetland was constructed and planted in the summer of 1994, at Eastern Municipal Water District’s (EMWD) Hemet/San Jacinto Regional Water Reclamation Facility (RWRF) in southern California. From January 1996 through September 1997, the marsh–pond–marsh wetland system was operated to polish an average of 3785 m3 d−1 (1×106 gal day−1) of secondary-treated effluent from the RWRF. Nitrogen removal was a major objective of this wetland treatment. Weekly inflow/outflow water quality monitoring of the wetland was supplemented with biannual, 45-station synoptic surveys within the system to determine internal distribution patterns of the nitrogen species (total ammonia, nitrite, nitrate, and organic nitrogen), total organic carbon (TOC), and ultraviolet absorbance at 254 nm (UV254). Synoptic surveys were carried out during May 22 and September 17, 1996, and May 6 and September 25, 1997 and the results were mapped using the ARC/INFO processing package and inverse distance weighted mathematical techniques. Distribution patterns of the various nitrogen species, TOC, and UV254 within the wetland indicate that the nitrogen dynamics of the system are influenced both by variations in treatment plant loading, and, increasingly, by the degree of coverage and maturity of the emergent vegetation.

  18. Environmental monitoring and assessment of the water bodies of a pre-construction urban wetland. (United States)

    Zuo, Shengpeng; Wan, Kun; Zhou, Shoubiao; Ye, Liangtao; Ma, Sumin


    It is planned that the Dayanghan Wetland in China will be transformed into a national park but little is known about its current water quality and pollution status. Thus, we monitored the physical and chemical characteristics of the Dayanghan Wetland, which showed that the water quality was generally good. However, the chemical oxygen demand was more than double the reference value, which may be attributable to previous tillage for vegetable crops and other farmlands. In addition, nickel and chromium caused low-level pollution in the water bodies of the Dayanghan Wetland. The mean trophic level index and nutrient quality index were 39.1 and 2.69, respectively. Both indices suggest that the water bodies of the Dayanghan Wetland are in a mesotrophic state and that no eutrophication has occurred. The study would provide a precise report on the status of environmental quality of the water bodies of a typical pre-construction wetland for the administration and decision of the local government and the planning agent.

  19. Distribution and turnover of carbon in natural and constructed wetlands in the Florida Everglades

    Energy Technology Data Exchange (ETDEWEB)

    Stern, J. [Department of Geological Sciences, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306-4100 (United States); NASA Ames Research Center, Moffett Field, CA 94035 (United States); Wang, Y. [Department of Geological Sciences, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306-4100 (United States)], E-mail:; Gu, B.; Newman, J. [Everglades Division, South Florida Water Management District, West Palm Beach, FL 33406 (United States)


    Stable and radiocarbon isotopic contents of dissolved organic C (DOC), dissolved inorganic C (DIC), particulate organic C (POC) and plants were used to examine the source and turnover rate of C in natural and constructed wetlands in the Florida Everglades. DOC concentrations decreased, with P concentrations, along a water quality gradient from the agriculturally impacted areas in the northern Everglades to the more pristine Everglades National Park. {delta}{sup 13}C values of DOC in the area reflect contributions of both wetland vegetation and sugarcane from agriculture. Radiocarbon ages of DOC, POC and DIC in the Everglades ranged from 2.01 ka BP to '>modern'. The old {sup 14}C ages of DOC and POC were found in impacted areas near the Everglades Agricultural Area (EAA) in the northern Everglades. In contrast, DOC and POC in pristine marsh areas had near modern or '>modern'{sup 14}C ages. These data indicate that a major source of POC and DOC in impacted areas is the degradation of historic peat deposits in the EAA. In the pristine areas of the marsh, DOC represents a mix of modern and historic C sources, whereas POC comes from modern primary production as indicated by positive {delta}{sup 14}C values, suggesting that DOC is transported farther away from its source than POC. High {delta}{sup 14}C values of DIC indicate that dissolution of limestone bedrock is not a significant source of DIC in the Everglades wetlands. As a restored wetland moves towards its 'original' or 'natural' state, the {sup 14}C signatures of DOC should approach that of modern atmosphere. In addition, measurements of concentration and C isotopic composition of DOC in two small constructed wetlands (i.e., test cells) indicate that these freshwater wetland systems contain a labile DOC pool with rapid turnover times of 26-39 days and that the test cells are overall net sinks of DOC.

  20. Treatment of artificial wastewater containing two azo textile dyes by vertical-flow constructed wetlands. (United States)

    Hussein, Amjad; Scholz, Miklas


    The release of untreated dye textile wastewater into receiving streams is unacceptable not only for aesthetic reasons and its negative impacts on aquatic life but also because numerous dyes are toxic and carcinogenic to humans. Strategies, as of now, used for treating textile wastewaters have technical and economical restrictions. The greater part of the physico-chemical methods, which are used to treat this kind of wastewater, are costly, produce large amounts of sludge and are wasteful concerning some soluble dyes. In contrast, biological treatments such as constructed wetlands are cheaper than the traditional methods, environmental friendly and do not produce large amounts of sludge. Synthetic wastewater containing Acid Blue 113 (AB113) and Basic Red 46 (BR46) has been added to laboratory-scale vertical-flow construction wetland systems, which have been planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). The concentrations 7 and 208 mg/l were applied for each dye at the hydraulic contact times of 48 and 96 h. Concerning the low concentrations of BR46 and AB113, the unplanted wetlands are associated with significant (ρ < 0.05) reduction performances, if compared with planted wetlands concerning the removal of dyes. For the high concentrations of AB113, BR46 and a mixture of both of them, wetlands with long contact times were significantly (ρ < 0.05) better than wetlands that had short contact times in terms of dye, colour and chemical oxygen demand reductions. Regarding nitrate nitrogen (NO 3 -N), the reduction percentage rates of AB113, BR46 and a mixture dye of both of them were between 85 and 100%. For low and high inflow dye concentrations, best removals were generally recorded for spring and summer, respectively.

  1. Removal of nutrients and metals by constructed and naturally created wetlands in the Las Vegas Valley, Nevada. (United States)

    Adhikari, Achyut R; Acharya, Kumud; Shanahan, Seth A; Zhou, Xiaoping


    Increased water use associated with rapid growth in the Las Vegas Valley has inadvertently led to the creation of unique wetland systems in Southern Nevada with an abundance of biological diversity. Constructed and naturally created wetlands in the Las Vegas Valley watershed were studied to characterize and understand their potential role for improving ecosystem services (i.e., water purification). Nutrient and metal removal was assessed at four sites including a natural urban runoff wetland, a constructed urban runoff wetland, a constructed wastewater wetland, and a natural urban runoff/wastewater wetland. Plant nutrient uptake was dependent on ambient nutrient concentrations in water and sediments of specific wetlands, irrespective of the type of plants present. Phosphorus was mostly concentrated in below-ground plant parts whereas nitrogen was concentrated in above-ground parts. As for metalloids, bulrushes were more efficient than cattails at taking up arsenic and selenium. Averaging all the wetland sites and plant species, total nitrogen, phosphorus, arsenic and selenium removal was 924.2, 61.5, 0.30, and 0.38 kg/ha/year, respectively. Our findings suggest that natural and created wetland systems can improve water quality in the Las Vegas Valley watershed for some common pollutants, however, other measures are still needed to improve water quality below regulatory thresholds.

  2. Removing heavy metals from Isfahan composting leachate by horizontal subsurface flow constructed wetland. (United States)

    Bakhshoodeh, Reza; Alavi, Nadali; Soltani Mohammadi, Amir; Ghanavati, Hossein


    Composting facility leachate usually contains high concentrations of pollutants including heavy metals that are seriously harmful to the environment and public health. The main purpose of this study was to evaluate heavy metals removal from Isfahan composting facility (ICF) leachate by a horizontal flow constructed wetland (HFCWs) system. Two horizontal systems were constructed, one planted with vetiver and the other without plant as a control. They both operated at a flow rate of 24 L/day with a 5-day hydraulic retention time (HRT). The average removal efficiencies for Cr (53 %), Cd (40 %), Ni (35 %), Pb (30 %), Zn (35 %), and Cu (40 %) in vetiver constructed wetland were significantly higher than those of the control (P < 0.05). Accumulations of heavy metals in roots were higher than shoots. Cd and Zn showed the highest and the lowest bioconcentration factor (BCF), respectively. Vetiver tolerates the extreme condition in leachate including high total dissolved solids.


    The use of constructed wetlands as a cost effective and environmentally friendly option for wastewater treatment is becoming more prevalent. These systems are championed as combining many of the benefits of tertiary treatment while also providing high quality wetland habitat as...

  4. Evaluation of Constructed Wetlands and Pretreatment Options For the Treatment of Flow-through Trout Farm Effluent


    Doheny, Ryan Matthew


    Horizontal subsurface flow (HSSF) constructed wetlands were evaluated for the treatment of flow-through trout farm effluent, phosphorus sorption affinity of gravel-bed media, and influence on Rhodamine WT (RWT) transport. HSSF wetlands coupled with mechanical pretreatment demonstrated significant (p

  5. Nutrient removal and bacterial communities in swine wastewater lagoon and constructed wetlands. (United States)

    Dong, Xiuli; Reddy, Gudigopuram B


    Surface constructed wetlands, including marsh-pond-marsh (MPM) and continuous marsh (CtM) were used to treat swine wastewater in this study. The objectives of this research were to evaluate the surface constructed wetland effects on swine wastewater treatment, and to investigate bacterial distribution shifts along treatment flows. Water quality parameters and bacterial community diversity were analyzed in each section of the entire wastewater treatment system, which was from the anaerobic lagoons (La1 and La2), through the wetlands, to the storage lagoon (La3) receiving wetland effluent. The results of water quality parameters demonstrated that the concentration of TKN, NH4+, o-PO4(3-), and COD decreased significantly (Pwetland cell, then there was no difference between MPM and CtM cells. The total bacterial community in each section of the system was examined by using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) technique. Our finding disclosed that the bacterial communities in different sections of the wastewater treatment system showed high diversities. The bacterial community compositions shifted gradually with the wastewater treatment procedure. Principal component analysis (PCA) and redundancy analysis (RDA) confirmed that the bacterium species distribution was strongly related to the COD, o-PO4(3-), and TKN concentrations, whereas moderately related to the NH4+ concentration. Flavobacterium sp. and Methylomonas sp. were detected according to partial 16S rRNA gene sequences.

  6. Contaminant removal in septage treatment with vertical flow constructed wetlands operated under batch flow conditions. (United States)

    Jong, Valerie Siaw Wee; Tang, Fu Ee


    Individual septic tanks are the most common means of on-site sanitation in Malaysia, but they result in a significant volume of septage. A two-staged vertical flow constructed wetlands (VFCWs) system for the treatment of septage was constructed and studied in Sarawak, Malaysia. Raw septage was treated in the first stage wetlands, and the resulting percolate was fed onto the second stage wetlands for further treatment. Here, the effects of a batch loading regime on the contaminant removal efficiency at the second stage wetlands, which included palm kernel shell within their filter substrate, are presented. The batch loading regime with pond:rest (P:R) period of 1:1, 2:2 and 3:3 (day:day) was studied. The improvement of the effluent redox condition was evident with P:R = 3:3, resulting in excellent organic matters (chemical oxygen demand and biochemical oxygen demand) and nitrogen reduction. The bed operated with P:R = 1:1 experienced constant clogging, with a water layer observed on the bed surface. For the P:R = 3:3 regime, the dissolved oxygen profile was not found to decay drastically after 24 hours of ponding, suggesting that the biodegradation mainly occurred during the first day. The study results indicate that a suitable application regime with an adequate rest period is important in VFCWs to ensure efficient operation.

  7. Evaluation of evapotranspiration in small on-site HSF constructed wetlands. (United States)

    Papaevangelou, Vassiliki A; Gikas, Georgios D; Tsihrintzis, Vassilios A


    Experimental results on evapotranspiration (ET), relevant to small on-site facilities are presented, derived from one-year controlled experiments in five pilot-scale horizontal subsurface flow (HSF) constructed wetlands (CW) used as lysimeters. The CW units operated in Northern Greece. They were rectangular tanks made of steel, with dimensions 3m long, 0.75m wide and 1m deep. Three different porous media were used, i.e., medium gravel, fine gravel and cobbles. Two plants were used, namely common reed (R, Phragmites australis) and cattails (C, Typha latifolia). One unit was unplanted. ET was estimated based on the water budget method. Conclusions were drawn on its relation to season and vegetation density. Furthermore, Pearson correlation coefficient analysis identified the main factors affecting wetland plant ET. Seven well-known ET empirical methods were applied to estimate ET using the measured meteorological and wetland data. ET estimated by the empirical methods were multiplied with appropriate correction coefficients to match measured ET, providing this way appropriate plant coefficient (K(c)) values, and equations for predicting HSF CW evapotranspiration. The suitability of these methods for the particular constructed wetland type is discussed through comparison with the measured data. The Blaney-Criddle method was found as best. Furthermore, stepwise multiple linear regression analysis was used with the measured ET and meteorological data to produce simple empirical equations to predict ET rates according to meteorological factors, plant and substrate material.

  8. Treatment of Alkaline Stripped Effluent in Aerated Constructed Wetlands: Feasibility Evaluation and Performance Enhancement

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    Keli He


    Full Text Available Ammonium stripping has gained increasing interest for nitrogen recovery in anaerobically digested effluents. However, the stripped effluents often still do not meet discharge standards, having high pH and residual pollutants. Constructed wetlands (CWs are an easy to operate ecosystem and have a long history of application in treatment of wastewaters with extreme pH, such as acid mine drainage. However, knowledge of the mechanistic details involved in the use of CWs to treat high alkaline drainage, such as stripped effluent, is insufficient. This study explored the feasibility and effectiveness of using three sub-surface horizontal flow CWs to treat high alkaline stripped effluent (pH > 10. Two intensification strategies—intermittent aeration and effluent recirculation—were evaluated to enhance nitrogen depuration performance. The results show that the treatment of alkaline stripped effluent is feasible due to the high buffering capacity of the wetlands. Effluent recirculation combined with intermittent artificial aeration improves nitrogen removal, with 71% total nitrogen (TN removal. Ammonia volatilization from the surface of the wetlands in high alkaline conditions only contributed to 3% of the total removed ammonium. The microbial abundance and activity had significant diversity for the various enhancement strategies used in the constructed wetland systems. Anammox is an important process for nitrogen removal in CWs treating alkaline stripped effluent, and possible enhancements of this process should be investigated further.

  9. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture. (United States)

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan


    A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD5, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO2-N, 90%) and nitrate nitrogen (NO3-N, 68%). Phosphate (PO4-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO3-N in the culture tank water in RAS were significantly (Pwetland treatment. However, no significant difference (PNO2-N was found between the two systems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8 +/-1.8 g/shrimp and 90%) significantly (Pwetlands can improve the water quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system.

  10. The phytoremediation ability of a polyculture constructed wetland to treat boron from mine effluent

    Energy Technology Data Exchange (ETDEWEB)

    Türker, Onur Can [Faculty of Science and Letters, Department of Biology, Aksaray University, Aksaray (Turkey); Böcük, Harun, E-mail: [Faculty of Science, Department of Biology, Anadolu University, Eskişehir (Turkey); Yakar, Anıl [Faculty of Science, Department of Biology, Anadolu University, Eskişehir (Turkey)


    Highlights: ► We assessed the phytoremediation ability of a polyculture constructed wetland (PCW) to treat boron (B) from mine effluent. ► B in mine effluent decreased from 187 mg l{sup −1} to 123 mg l{sup −1} (32% removal rate) through the PCW. ► Estimated methane production, energy yields and electrical energy yields of the PCW increased with biomass production. ► Cattails accumulated more than 250 mg kg{sup −1} B and common reed accumulated 38 mg kg{sup −1} B at the end of the experiment. -- Abstract: This study focuses on describing the ability of a small-scale, subsurface-flow-polyculture-constructed wetland (PCW) to treat boron (B) mine effluent from the world's largest borax mine (Kırka, Turkey) under field conditions. This application is among the first effluent treatment methods of this type in both Turkey and the world. This study represents an important resource on how subsurface-flow-constructed wetlands could be used to treat B mine effluents in the field conditions. To this end, an experimental wetland was vegetated with common reed (Phragmites australis) and cattails (Typha latifolia), and mine effluent was moved through the wetland. The results of the present study show that B concentrations of the mine effluent decreased from 187 to 123 mg l{sup −1} (32% removal rate) on average. The T. latifolia individuals absorbed a total of 250 mg kg{sup −1} whereas P. australis in the PCW absorbed a total of 38 mg kg{sup −1} B during the research period.

  11. Planting richness affects the recovery of vegetation and soil processes in constructed wetlands following disturbance (United States)

    Means, Mary M.; Ahn, Changwoo; Noe, Gregory


    The resilience of constructed wetland ecosystems to severe disturbance, such as a mass herbivory eat-out or soil disturbance, remains poorly understood. In this study, we use a controlled mesocosm experiment to examine how original planting diversity affects the ability of constructed freshwater wetlands to recover structurally and functionally after a disturbance (i.e., aboveground harvesting and soil coring). We assessed if the planting richness of macrophyte species influences recovery of constructed wetlands one year after a disturbance. Mesocosms were planted in richness groups with various combinations of either 1, 2, 3, or 4 species (RG 1–4) to create a gradient of richness. Structural wetland traits measured include morphological regrowth of macrophytes, soil bulk density, soil moisture, soil %C, and soil %N. Functional wetland traits measured include above ground biomass production, soil potential denitrification, and soil potential microbial respiration. Total mesocosm cover increased along the gradient of plant richness (43.5% in RG 1 to 84.5% in RG 4) in the growing season after the disturbance, although not all planted individuals recovered. This was largely attributed to the dominance of the obligate annual species. The morphology of each species was affected negatively by the disturbance, producing shorter, and fewer stems than in the years prior to the disturbance, suggesting that the communities had not fully recovered one year after the disturbance. Soil characteristics were almost uniform across the planting richness gradient, but for a few exceptions (%C, C:N, and non-growing season soil moisture were higher slightly in RG 2). Denitrification potential (DEA) increased with increasing planting richness and was influenced by the abundance and quality of soil C. Increased open space in unplanted mesocosms and mesocosms with lower species richness increased labile C, leading to higher C mineralization rates.

  12. [Removal nitrogen of integrated vertical-flow constructed wetland under aeration condition]. (United States)

    Tao, Min; He, Feng; Xu, Dong; Zhou, Qiao-Hong; Liang, Wei; Chen, Shui-Ping; Wu, Zhen-Bin


    Oxygen is an important limit factor of nitrogen removal in constructed wetlands, so it is the key point for improving nitrogen removal efficiency of constructed wetlands that the optimization of oxygen distribution within wetlands. Therefore, oxygen status, nitrogen removal and purification mechanism of integrated vertical-flow constructed wetland (IVCW) under aeration condition in summer and winter have been studied. The results showed that both oxygen levels and aerobic zones were increased in the wetland substrates. The area of oxic zone I (expressing with depth) extended from 22 cm, 17 cm to 53 cm, 44 cm, in summer and winter, respectively. The electric potential (Eh) profiling demonstrated that artificial aeration maintained the pattern of sequential oxic-anoxic-oxic (O-A-O) redox zones within the aerated IVCW in winter, while only two oxic-anoxic (O-A) zones were present inside the non-aerated IVCW in the cold season. The decomposition of organic matter and nitrification were obviously enhanced by artificial aeration since the removal efficiency of COD, TN and NH4(+) -N were increased by 12.2%, 6.9% and 15.1% in winter, respectively. There was no significant accumulation of NO3(-) -N in the effluent with an aeration cycle of 8 h on and 16 h off in this experiment. Moreover, we found that oxic zone I was the main region of pollutants removal in IVCW system, and artificial aeration mainly acted to enhance the purification capacity of this oxic zone in the aerated IVCW. These results suggest that aeration is important for optimization and application of IVCW system.

  13. The effects of bird use on nutrient removal in a constructed wastewater-treatment wetland (United States)

    Andersen, D.C.; Sartoris, J.J.; Thullen, J.S.; Reusch, P.G.


    A 9.9-ha constructed wetland designed to reduce nitrogen in municipal wastewater following conventional secondary treatment began operating in southern California's San Jacinto Valley in September 1994. The wetland incorporated zones of bulrush (Schoenoplectus acutus and S. californicus) for effluent treatment, plus areas of 1.8-m deep open water and other features to benefit wintering waterfowl. A one-year long program to monitor bird use and evaluate their contribution to loadings of nitrogen and phosphorus was initiated seven months later and a second, four-month long period of monitoring was initiated after a 20-month hiatus. Daily bird use peaked at nearly 12,000 individuals during the second period. Estimates of maximum daily nitrogen and phosphorus input by birds were 139 g N ha−1 day−1 and 56 g P ha−1 day−1. Following a reconfiguration of the wetland that increased the area of open water, a third year-long period of monitoring was initiated in September 2000. Estimated maximum daily loading attributable to birds during this period reached 312 g N ha−1 day−1 and 124 g P ha−1 day−1. These levels represent only 2.6% and 7.0%, respectively, of the mean daily loads of N and P in inflow water from the wastewater-treatment plant. Wintering waterfowl contributed the most to nutrient loading, but the numerically dominant species was the colonial Red-winged Blackbird (Agelaius phoeniceus). The wetland's nutrient-removal efficiency was negatively correlated to bird loading. However, the greatest bird loading occurred during November to March, when winter conditions would reduce microbial nutrient-removal processes and plant uptake in the wetland. Multiple regression analysis indicated that variation in nutrient removal efficiency over a one-year period was best explained by wetland water temperature (R2 = 0.21) and that little additional insight was gained by adding bird loading and inflow nutrient load data (R2 = 0.22). This case study supports the

  14. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

    Directory of Open Access Journals (Sweden)

    Qingqing Cao

    Full Text Available Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types. However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

  15. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China. (United States)

    Cao, Qingqing; Wang, Renqing; Zhang, Haijie; Ge, Xiuli; Liu, Jian


    Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

  16. Iron oxides stimulate microbial monochlorobenzene in situ transformation in constructed wetlands and laboratory systems. (United States)

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


    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. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Candidate soil indicators for monitoring the progress of constructed wetlands toward a natural state: a statistical approach (United States)

    Stapanian, Martin A.; Adams, Jean V.; Fennessy, M. Siobhan; Mack, John; Micacchion, Mick


    A persistent question among ecologists and environmental managers is whether constructed wetlands are structurally or functionally equivalent to naturally occurring wetlands. We examined 19 variables collected from 10 constructed and nine natural emergent wetlands in Ohio, USA. Our primary objective was to identify candidate indicators of wetland class (natural or constructed), based on measurements of soil properties and an index of vegetation integrity, that can be used to track the progress of constructed wetlands toward a natural state. The method of nearest shrunken centroids was used to find a subset of variables that would serve as the best classifiers of wetland class, and error rate was calculated using a five-fold cross-validation procedure. The shrunken differences of percent total organic carbon (% TOC) and percent dry weight of the soil exhibited the greatest distances from the overall centroid. Classification based on these two variables yielded a misclassification rate of 11% based on cross-validation. Our results indicate that % TOC and percent dry weight can be used as candidate indicators of the status of emergent, constructed wetlands in Ohio and for assessing the performance of mitigation. The method of nearest shrunken centroids has excellent potential for further applications in ecology.


    Directory of Open Access Journals (Sweden)

    Monika Puchlik


    Full Text Available About 2000 plants are involved in fruit and vegetable processing in Poland, they are mostly located in non-urbanized areas and without any access to sewerage and sewage treatment facilities. In 2014, they produced more than 10 hm3 of wastewater requiring treatment, which was discharged directly into surface waters or into the ground. The aim of the study was to evaluate the efficiency of the constructed wetland for treating the sewage from fruit and vegetable industry. The analyzed constructed wetland with vertical flow reveled a reduction in the value of BOD5 to 68.2%, and CODCr to 79.3%. The model was characterized by 60.2% efficiency of total phosphorus removal.

  19. Environmental assessment for the A-01 outfall constructed wetlands project at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)



    The Department of Energy (DOE) prepared this environmental assessment (EA) to analyze the potential environmental impacts associated with the proposed A-01 outfall constructed wetlands project at the Savannah River site (SRS), located near aiken, South Carolina. The proposed action would include the construction and operation of an artificial wetland to treat effluent from the A-01 outfall located in A Area at SRS. The proposed action would reduce the outfall effluent concentrations in order to meet future outfall limits before these go into effect on October 1, 1999. This document was prepared in compliance with the National Environmental Policy Act (NEPA) of 1969, as amended; the requirements of the Council on Environmental Quality Regulations for Implementing NEPA (40 CFR Parts 1500--1508); and the DOE Regulations for Implementing NEPA (10 CFR Part 1021).

  20. Distribution and removal efficiency of heavy metals in two constructed wetlands treating landfill leachate. (United States)

    Wojciechowska, Ewa; Waara, Sylvia


    The results of heavy metals (Fe, Mn, Zn, Ni, Cu, Cr, Pb, Cd) removal and partitioning between aqueous and solid phases at two treatment wetlands (TWs) treating municipal landfill leachates are presented. One of the TWs is a surface flow facility consisting of 10 ponds. The other TW is a newly constructed pilot-scale facility consisting of three beds with alternately vertical and horizontal subsurface flow. The metals concentrations were analysed in leachate (both TWs) and bottom sediments (surface flow TW). Very high (90.9-99.9%) removal rates of metals were observed in a mature surface flow TW. The effectiveness of metals removal in a newly constructed pilot-scale sub-surface flow wetland were considerably lower (range 0-73%). This is attributed to young age of the TW, different hydraulic conditions (sub-surface flow system with much shorter retention time, unoxic conditions) and presence of metallic complexes with refractory organic matter.

  1. Use of macrophyte plants, sand & gravel materials in constructed wetlands for greywater treatment (United States)

    Qomariyah, S.; Ramelan, AH; Sobriyah; Setyono, P.


    Greywater discharged without any treatments into drainage channels or natural water bodies will lead to environmental degradation and health risk. Local macrophyte plants combined with natural materials of sand and gravel have been used in a system of constructed wetland for the treatment of the greywater. This paper presents the results of some studies of the system carried out in Indonesia, Thailand, and Costa Rica. The studies demonstrate the success of the constructed wetland systems in removing some pollutants of BOD, COD, TSS, pathogen, and detergent. The studies resulted in the treated water in a level of treatment that fulfils the requirement of the local standards for wastewater reuse as irrigation water, fishery, or other outdoor needs.

  2. The Spatial Distribution of Nitrogen Removal Functional Genes in Multimedia Constructed Wetlands for Wastewater Treatment. (United States)

    Ji, Guodong; He, Chunguang; Tan, Yufei; Yang, Zhonghua


    The real-time polymerase chain reaction was used to quantitatively evaluate distribution patterns and nitrogen removal pathways of the amoA, nxrA, narG, napA, nirK, qnorB, nosZ, nas, and nifH genes and 16S rRNA in anaerobic ammonia oxidation bacteria in four multimedia constructed wetlands for rural wastewater treatment. The results indicated that the abundance of functional genes for nitrogen removal in the rhizosphere layer (0 to 30 cm), water distribution layer (30 to 50 cm), multime filler layer (50 to 130 cm), and catchment layer (130 to 170 cm) of the constructed wetlands were closely related. The rhizosphere layer was conducive to the absolute enrichment of dominant genes. The other three layers were favorable to the relative enrichment of rare genes.

  3. Assessment of the microbial community in a constructed wetland that receives acid coal mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nicomrat, D.; Dick, W.A.; Tuovinen, O.H. [Ohio State University, Columbus, OH (United States)


    Constructed wetlands are used to treat acid drainage from surface or underground coal mines. However, little is known about the microbial communities in the receiving wetland cells. The purpose of this work was to characterize the microbial population present in a wetland that was receiving acid coal mine drainage (AMD). Samples were collected from the oxic sediment zone of a constructed wetland cell in southeastern Ohio that was treating acid drainage from an underground coal mine seep. Samples comprised Fe(Ill) precipitates and were pretreated with ammonium oxalate to remove interfering iron, and the DNA was extracted and purified by agarose gel electrophoresis prior to amplification of portions of the 16S rRNA gene. Amplified products were separated by denaturing gradient gel electrophoresis and DNA from seven distinct bands was excised from the gel and sequenced. The sequences were matched to sequences in the GenBank bacterial 16S rDNA database. The DNA in two of the bands yielded matches with Acidithiobacillus ferrooxidans and the DNA in each of the remaining five bands was consistent with one of the following microorganisms: Acidithiobacillus thiooxidans, strain TRA3-20 (a eubacterium), strain BEN-4 (an arsenite-oxidizing bacterium), an Alcaligenes sp., and a Bordetella sp. Low bacterial diversity in these samples reflects the highly inorganic nature of the oxic sediment layer where high abundance of iron- and sulfur-oxidizing bacteria would be expected. The results we obtained by molecular methods supported our findings, obtained using culture methods, that the dominant microbial species in an acid receiving, oxic wetland are A. thiooxidans and A. ferrooxidans.

  4. Comparison of aerated marsh-pond-marsh and continuous marsh constructed wetlands for treating swine wastewater. (United States)

    Forbes, Dean A; Reddy, G B; Hunt, Patrick G; Poach, M E; Ro, Kyoung S; Cyrus, Johnsely S


    Increased swine production in North Carolina has resulted in greater waste generation and is demanding some emerging new innovative technologies to effectively treat swine wastewater. One of the cost-effective and passive methods to treat swine wastewater is using constructed wetlands. The objective of this study was to evaluate the N removal under two N loads in 3 different wetland systems: aerated marsh-pond-marsh (M-P-M), aerated marsh-covered pond-marsh (M-FB-M), and continuous marsh (CM) with two days drain and five days flood cycle. Swine wastewater from an anaerobic lagoon was applied to the constructed wetland cells (11 m wide x 40 m length) at two N loading rates of 7 and 12 kg N ha(-1) day(-1)from June to July and August to September 2005, respectively. Weekly inflow and outflow samples were collected for N, P, TS, and COD analysis. Total N reductions (%) at low and high N loading rates were 85.8 and 51.8; 86.3 and 63.3; and 86.2 and 61.8 for M-P-M, M-FB-M, and CM, respectively. Aeration had no significant (P > 0.05) impact on N removal. However, significant (P 0.05) in N reduction was found among wetland systems. Vegetation uptake of N was negligible, ranging from 1.2 to 1.8 %. No significant (P > 0.05) differences in TS and COD removal were observed between the wetland systems.

  5. Stormwater constructed wetlands: A source or a sink of Campylobacter spp. (United States)

    Meng, Ze; Chandrasena, Gayani; Henry, Rebekah; Deletic, Ana; Kolotelo, Peter; McCarthy, David


    Stormwater constructed wetlands are not well characterised for their ability to remove pathogens which can pose public health risks during stormwater harvesting activities. This study investigated the behaviour of faecal indicator organism Escherichia coli (E. coli) and reference pathogen Campylobacter spp. in stormwater constructed wetlands, using a case study system located in Melbourne, Australia. Grab sampling and event-based monitoring revealed influent concentrations of E. coli were typical of other urban stormwater studies, yet Campylobacter concentrations were orders of magnitude above those urban stormwater studies used to develop the Australian Guidelines for Water Recycling, reached levels typical of raw domestic wastewater. The wetland consistently removed E. coli from stormwater (mean log removal 0.96, range 0.19-1.79), while Campylobacter spp. concentrations were often higher in outflow than inflow (mean log removal 0.05, range -0.9-1.25). These results indicate that E. coli is a poor indicator for this reference pathogen. The log reductions of both organisms also failed to meet the criteria specified for any end-use, as listed in the Australian Guidelines for Water Recycling, suggesting further treatment is required prior to harvesting. Finally, this study proposed that direct faecal deposition by waterfowl faeces was a microbial source to stormwater wetlands and that this was partly responsible for the varied microbial removal rates observed. Overall, this work validates the need for further characterisation of pathogens in raw urban stormwater, and the ability for water sensitive urban design features, such as wetlands, to remove both indicator and pathogenic microorganisms. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  6. Municipal wastewater treatment in an anaerobic digester-constructed wetland system. (United States)

    Ruiz, I; Alvarez, J A; Díaz, M A; Serrano, L; Soto, M


    An experimental plant was constituted for an upflow anaerobic sludge blanket (UASB) reactor with an active volume of 25.5 m3 and two horizontal constructed wetlands of 75 m2 each. The first wetland was a superficial flow (SF) system and the second a subsurface flow (SSF) system. The UASB reactor was fed with 60-73 m3 d(-1) of raw domestic wastewater from the municipal treatment plant (MTP) of the city of Santiago de Compostela. Part of the effluent from the UASB reactor (15 m3 d(-1)) passed through the SF wetland and then went into the SSF. In the first ten months of operation, from July 2005 to April 2006, the hydraulic retention time for the UASB system was in the range of 7-14 hours and the organic loading rate (OLR) was between 0.3 and 1.1 g COD l(-1) d(-1). The organic load in the wetlands was in the range of 5-40 g BOD5 m(-2) d(-1). The global results achieved for total suspended solids (TSS), chemical oxygen demand (COD) and biological oxygen demand (BOD5) removal efficiencies were 85-96%, 65-90% and 69-93%, respectively. The average monthly concentrations in the final effluent were 8-73 mg BOD5 l(-1), 25-120 mg COD l(-1) and 6-20 mg TSS l(-1). The global balance of VSS in the UASB reactor shows that purge accounted for 19.6% and hydrolysis accounted for 47.7% of influent VSS. Data from suspended solids balance in the constructed wetlands, at the end of the operation period, show a TSS and VSS accumulation of 48% and 16%, respectively.



    Rodriguez Caballero, Adrian


    Winery wastewater is characterized by its high chemical oxygen demand (COD), seasonal occurrence and variable composition, including periodic high ethanol concentrations. In addition, winery wastewater may contain insufficient inorganic nutrients for optimal biodegradation of organic constituents. Two pilot-scale constructed wetlands (CWs) were used to treat artificial wastewater: the first was amended with ethanol and the second with ethanol, inorganic nitrogen (N) and phosphorus (P). A numb...

  8. Removal of emerging organic pollutants in constructed wetlands: imazalil and tebuconazole as model pesticides


    Lyu, Tao


    The pesticides imazalil and tebuconazole are commonly used to protect variousagricultural crops against fungal attack or as biocides for wood protection, as such, they have been found in both rural and urban water bodies. The emerging pesticides are gaining prominence due to the toxic effects on aquatic environment and human health. Constructed wetland systems (CWs) have been an economical, robust and sustainable technology for wastewater treatment, and are emerging for the treatment of pesti...

  9. Removal of the pesticide tebuconazole in constructed wetlands: design comparison, influencing factors and modelling


    Lyu, T; Zhang, L; Xu, X; Arias, CA; Brix, H; Carvalho, PN


    Constructed wetlands (CWs) are a promising technology to treat pesticide contaminated water, but its implementation is impeded by lack of data to optimize designs and operating factors. Unsaturated and saturated CW designs were used to compare the removal of triazole pesticide, tebuconazole, in unplanted mesocosms and mesocosms planted with five different plant species: Typha latifolia, Phragmites australis, Iris pseudacorus, Juncus effusus and Berula erecta. Tebuconazole removal efficiencies...

  10. Using sorbent waste materials to enhance treatment of micro-point source effluents by constructed wetlands


    Green, Verity; Surridge, Ben; Quinton,John; Matthews, Mike


    Sorbent materials are widely used in environmental settings as a means of = enhancing pollution remediation. A key area of environmental concern is that of water pollution, including the need to treat micro-point sources of wastewater pollution, such as from caravan sites or visitor centres. Constructed wetlands (CWs) represent one means for effective treatment of wastewater from small wastewater producers, in part because they are believed to be economically viable and environmentally sustai...

  11. Water Purification Characteristic of the Actual Constructed Wetland with Carex dispalata in a Cold Area (United States)

    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.

  12. Removal of chlorpyrifos insecticide in constructed wetlands with different plant species

    Directory of Open Access Journals (Sweden)

    Tamara D. de Souza

    Full Text Available ABSTRACT The objective of this study was to evaluate the remediation of water containing the insecticide chlorpyrifos by using constructed wetlands (CW cultivated with Polygonum punctatum, Cynodon spp. and Mentha aquatica, operated under different hydraulic retention times: 24, 48, 96, 144 and 192 h. The system efficiency was based on reduction of the initial concentration of chlorpyrifos and toxicity of the contaminated water. The results showed that constructed wetlands are an excellent alternative for remediation of the insecticide chlorpyrifos in aqueous medium. It was observed that the average overall removal efficiency of the insecticide was 98.6%, and in the first hydraulic retention time, 24 h, chlorpyrifos was removed to levels below the detection limit in all CW. This result is mainly attributed to adsorption and microbial degradation. For the qualitative standard acute toxicity tests with Daphnia similis, for most samples there was a reduction in toxicity greater than 80%. It was reported that the ecotoxicological tests with the effluents of the constructed wetland are a good option as an indicator of the effectiveness of treatments and a promising alternative to complement the physical and chemical analyses.

  13. Estrogen degradation and sorption onto colloids in a constructed wetland with different hydraulic retention times. (United States)

    Chen, Ting-Chien; Yeh, Kuei-Jyum C; Kuo, Wen-Chien; Chao, How-Ran; Sheu, Shyang-Chwen


    Endocrine disrupting compounds are a global concern, owing to their interference with the endocrine system of wildlife. In particular, natural estrogens at concentrations as low as ng/L level can interrupt the endocrine system of many organisms. A constructed wetland is an effective means of removing the residual levels of estrogen. This study investigates the estrogen degradation and sorption on colloids in a constructed wetland at hydraulic retention times (HRTs) of 27.5, 45.9, and 137.5h. Three natural estrogens (i.e. estrone (E1), 17β-estradiol (E2), and estriol (E3)) are analyzed with liquid chromatography/tandem mass spectrometry. At HRT=27.5h, no degradation occurs; at HRT=45.9h, the degradation rates are 0-46.2%; and at HRT=137.5h, the degradation rates are 40-84.3%. Additionally, estrogen sorption coefficients (logKCOC values) range from 3.37 to 4.89. Average logKCOC values are 4.08±0.33, 4.04±0.34, and 4.11±0.28 for E1, E2, and E3, respectively. At different HRTs, values of logKCOC increase with an increasing HRT. Analytical results indicate that constructed wetlands can remove residual natural estrogens. With an increasing HRT, the estrogen degradation rate increases as well as the estrogen sorption on colloids. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Performance of the subsurface flow constructed wetlands for pretreatment of slightly polluted source water. (United States)

    Yang, Xu; Zhang, Xueping; Wang, Jifu; Zhao, Guangying; Wang, Baojian


    The slightly polluted source water of Yellow River was pretreated in a horizontal subsurface flow constructed wetland (HSFCW) and a lateral subsurface flow constructed wetland (LSFCW) in the Ji'nan city Reservoir, Shandong, China. During almost one years run, the results showed that at the hydraulic loading rate of 1 m/day, the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), ammonium nitrogen (NH4 (+)-N) and total phosphorus (TP) in the HSFCW were 48.9, 51.4, 48.7 and 48.9 %, respectively, and the corresponding removal efficiencies in the LSFCW were 50.51, 53.12, 50.44 and 50.83 %, respectively. The HSFCW and LSFCW had a similar high potential for nutrients removal and LSFCW was slightly better. According to the China standard for surface water resources (GB3838-2002), mean effluent COD can reach the Class I (≤ 15 mg/L), and NH4 (+)-N and TP and TN can reach nearly the Class I (≤ 0.015 mg/L), the Class III (≤ 0.05 mg/L) and the Class IV (≤ 1.5 mg/L), respectively. It can be concluded that the slightly polluted source water from Reservoir was pretreated well by the constructed wetland.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Marie; Wolfram, Diana; Birkigt, Jan [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Ahlheim, Jörg [Department of Groundwater Remediation, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Paschke, Heidrun [Department of Analytical Chemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Richnow, Hans-Hermann [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Nijenhuis, Ivonne, E-mail: [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research — UFZ, Permoserstrasse 15, 04318 Leipzig (Germany)


    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. - Highlights: • MCB removal in anoxic gravel bed of a planted and an unplanted constructed wetland was accompanied by iron

  16. Investigations of subsurface flow constructed wetlands and associated geomaterial resources in the Akumal and Reforma regions, Quintana Roo, Mexico (United States)

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


    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.

  17. Intensified nitrogen and phosphorus removal in a novel electrolysis-integrated tidal flow constructed wetland system. (United States)

    Ju, Xinxin; Wu, Shubiao; Zhang, Yansheng; Dong, Renjie


    A novel electrolysis-integrated tidal flow constructed wetland (CW) system was developed in this study. The dynamics of intensified nitrogen and phosphorus removal and that of hydrogen sulphide control were evaluated. Ammonium removal of up to 80% was achieved with an inflow concentration of 60 mg/L in wetland systems with and without electrolysis integration. Effluent nitrate concentration decreased from 2 mg/L to less than 0.5 mg/L with the decrease in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2) in the electrolysis-integrated wetland system, thus indicating that the current intensity of electrolysis plays an important role in nitrogen transformations. Phosphorus removal was significantly enhanced, exceeding 95% in the electrolysis-integrated CW system because of the in-situ formation of a ferric iron coagulant through the electro-dissolution of a sacrificial iron anode. Moreover, the electrolyzed wetland system effectively inhibits sulphide accumulation as a result of a sulphide precipitation coupled with ferrous-iron electro-dissolution and/or an inhibition of bacterial sulphate reduction under increased aerobic conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Penurunan Logam Timbal (Pb) pada Limbah Cair TPA Piyungan Yogyakarta dengan Constructed Wetlands Menggunakan Tumbuhan Eceng Gondok (Eichornia Crassipes)


    Eko Siswoyo; Ir Kasam; L.M. Subhan Abdullah


    Salah satu permasalahan lingkungan yang ditimbulkan dari adanya lindi di TPA Piyungan yaitu pencemaran pada badan air, sungai dan air tanah. Untuk mengatasi permasalahan ini salah satunya dengan sistem Constructed Wetlands dengan menggunakan tumbuhah eceng gondok. Tujuan dari penelitian ini adalah untuk mengetahui tingkat penurunan konsentrasi Timbal (Pb) yang terdapat dalam limbah cair TPA Piyungan dengan Constructed Wetlands menggunakan tumbuhan eceng gondok dan untuk mengetahui seberapa be...

  19. Penurunan Logam Timbal (Pb) Pada Limbah Cair TPA Piyungan YOGYAKARTA Dengan Constructed Wetlands Menggunakan Tumbuhan Eceng Gondok (Eichornia Crassipes)


    Siswoyo, Eko; Kasam, Ir; L.M. Subhan Abdullah


    Salah satu permasalahan lingkungan yang ditimbulkan dari adanya lindi di TPA Piyungan yaitu pencemaran pada badan air, sungai dan air tanah. Untuk mengatasi permasalahan ini salah satunya dengan sistem Constructed Wetlands dengan menggunakan tumbuhah eceng gondok. Tujuan dari penelitian ini adalah untuk mengetahui tingkat penurunan konsentrasi Timbal (Pb) yang terdapat dalam limbah cair TPA Piyungan dengan Constructed Wetlands menggunakan tumbuhan eceng gondok dan untuk mengetahui seberapa be...

  20. Using cerium anomaly as an indicator of redox reactions in constructed wetland (United States)

    Liang, R.


    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 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 dissolved oxygen (5 ppm) but the NH4 content is still high, which indicates a non-equilibrium condition. In this study, the cerium anomaly is alternatively utilized to evaluate the water redox state. The results demonstrate that the input water has the negative cerium anomaly of -0.16. Along the flow path, the cerium negative anomaly

  1. Effects of plant root on hydraulic performance of clogging process in subsurface flow constructed wetland (United States)

    Hua, Guofen; Zhao, Zhongwei; Zeng, Yitao


    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

  2. Application of the gas tracer method for measuring oxygen transfer rates in subsurface flow constructed wetlands. (United States)

    Tyroller, Lina; Rousseau, Diederik P L; Santa, Santa; García, Joan


    The oxygen transfer rate (OTR) has a significant impact on the design, optimal operation and modelling of constructed wetlands treating wastewater. Oxygen consumption is very fast in wetlands and the OTR cannot be determined using an oxygen mass balance. This problem is circumvented in this study by applying the gas tracer method. Experiments were conducted in an unplanted gravel bed (dimensions L x W x d 125 x 50 x 35 cm filled with a 30-cm layer of 10-11-mm gravel) and a planted horizontal subsurface flow constructed wetland (HSSFCW) (L x W x d 110 x 70 x 38 cm filled with a 30-cm layer of 3.5-mm gravel with Phragmites australis). Tap water saturated with propane as gas tracer (pure or commercial cooking gas, depending on the test) was used. The mass transfer ratio between oxygen and commercial propane gas was quite constant and averaged R = 1.03, which is slightly lower than the value of R = 1.39 that is usually reported for pure propane. The OTR ranged from 0.31 to 5.04 g O(2) m(-2) d(-1) in the unplanted gravel bed and from 0.3 to 3.2 g O(2) m(-2) d(-1) in the HSSFCW, depending on the hydraulic retention time (HRT). The results of this study suggest that the OTR in HSSFCW is very low for the oxygen demand of standard wastewater and the OTR calculations based on mass balances and theoretical stoichiometric considerations overestimate OTR values by a factor that ranges from 10 to 100. The gas tracer method is a promising tool for determining OTR in constructed wetlands, with commercial gas proving to be a viable low-cost alternative for determining OTR. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Efficient removal of antibiotics in surface-flow constructed wetlands, with no observed impact on antibiotic resistance genes. (United States)

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


    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. Copyright © 2014 Elsevier B.V. All rights

  4. Comparative evaluation of low cost materials as constructed wetland filling media (United States)

    Pinho, Henrique J. O.; Vaz, Mafalda M.; Mateus, Dina M. R.


    Three waste materials from civil construction activities were assessed as low cost alternative filling materials used in Constructed Wetlands (CW). CW are green processes for wastewater treatment, whose design includes an appropriate selection of vegetation and filling material. The sustainability of such processes may be incremented using recovered wastes as filling materials. The abilities of the materials to support plant growth and to contribute to pollutants removal from wastewater were assessed and compared to expanded clay, a filling usually used in CW design. Statistical analysis, using one-way ANOVA and Welch's ANOVA, demonstrate that limestone fragments are a better choice of filling material than brick fragments and basalt gravel.

  5. Sustainability of Constructed Wetland under the Impact of Aquatic Organisms Overloading

    Directory of Open Access Journals (Sweden)

    Shih-Chieh Chen


    Full Text Available Environmental impacts, such as earthquakes, chemical pollution and anthropogenic factors can affect the stability and sustainability of an ecosystem. In this study, a long-term (3.7 years investigation experiment was conducted to estimate the sustainability of a constructed wetland (CW under the impact of aquatic organisms overloading. The situation of aquatic organisms overloading in this study meant that around 27,000 kg of fishes had to be moved and accommodated in a 4 ha water area of wetland for six months. Experimental results indicated that the pH value of CW water was slightly acidic and the Dissolved Oxygen (DO level decreased under the impact. On the other hand, the levels of Electrical Conductivity (EC, Suspended Solids (SS, Chemical Oxygen Demand (COD, and Total Kjeldahl Nitrogen (TKN of CW water were increased under the impact. The pathogen analysis revealed that total coliforms, Salmonella spp., Enterococcus spp., and Escherichia coli, in the wetland water increased under the impact. The analyzed factors of water quality and amount of pathogens were all returned to their original statuses soon after the impact ended. Eventually, the results of microbial community structure analysis showed that overloading of aquatic organisms slightly increased the specific richness (R of wetland bacteria, whereas higher structural biodiversity (H of CW could stabilize the whole microbial community and prevent the pathogens or other bacteria from increasing to become the dominant strains. These results were novel and could be possible to conclude that a CW environment could not only stabilize the water quality and amount of pathogens resulting from the impact of aquatic organisms overloading, but also they could stabilize the microbial community structures, allowing the biogeochemical cycles of the CW to function. They could provide the useful information for wetland sustainability.

  6. Phytoremediation of water contaminated with mercury using Typha domingensis in constructed wetland. (United States)

    Gomes, Marcos Vinícius Teles; de Souza, Roberto Rodrigues; Teles, Vinícius Silva; Araújo Mendes, Érica


    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Design and Season Influence Nitrogen Dynamics in Two Surface Flow Constructed Wetlands Treating Nursery Irrigation Runoff

    Directory of Open Access Journals (Sweden)

    Sarah A. White


    Full Text Available Constructed wetlands (CWs are used to remediate runoff from a variety of agricultural, industrial, and urban sources. CW remediation performance is often evaluated at the laboratory scale over durations less than one year. The purpose of this study was to characterize the effect of CW design (cell depth and residence time on nitrogen (N speciation and fate across season and years in two free water surface wetlands receiving runoff from irrigated plant production areas at an ornamental plant nursery. Water quality (mg·L−1 of nitrate, nitrite, and ammonium, dissolved oxygen and oxidation reduction potential was monitored at five sites within each of two CWs each month over four years. Nitrate-N was the dominant form of ionic N present in both CWs. Within CW1, a deep cell to shallow cell design, nitrate comprised 86% of ionic N in effluent. Within CW2, designed with three sequential deep cells, nitrate comprised only 66% of total N and ammonium comprised 27% of total N in CW2 effluent. Differences in ionic N removal efficacies and shifts in N speciation in CW1 and CW2 were controlled by constructed wetland design (depth and hydraulic retention time, the concentration of nutrients entering the CW, and plant species richness.

  8. Role of vegetation in a constructed wetland on nutrient-pesticide mixture toxicity to Hyalella azteca. (United States)

    Lizotte, Richard E; Moore, Matthew T; Locke, Martin A; Kröger, Robert


    The toxicity of a nutrient-pesticide mixture in nonvegetated and vegetated sections of a constructed wetland (882 m² each) was assessed using Hyalella azteca 48-h aqueous whole-effluent toxicity bioassays. Both sections were amended with a mixture of sodium nitrate, triple superphosphate, diazinon, and permethrin simulating storm-event agricultural runoff. Aqueous samples were collected at inflow, middle, and outflow points within each section 5 h, 24 h, 72 h, 7 days, 14 days, and 21 days postamendment. Nutrients and pesticides were detected throughout both wetland sections with concentrations longitudinally decreasing more in vegetated than nonvegetated section within 24 h. Survival effluent dilution point estimates-NOECs, LOECs, and LC₅₀s-indicated greatest differences in toxicity between nonvegetated and vegetated sections at 5 h. Associations of nutrient and pesticide concentrations with NOECs indicated that earlier toxicity (5-72 h) was from permethrin and diazinon, whereas later toxicity (7-21 days) was primarily from diazinon. Nutrient-pesticide mixture concentration-response assessment using toxic unit models indicated that H. azteca toxicity was due primarily to the pesticides diazinon and permethrin. Results show that the effects of vegetation versus no vegetation on nutrient-pesticide mixture toxicity are not evident after 5 h and a 21-day retention time is necessary to improve H. azteca survival to ≥90% in constructed wetlands of this size.

  9. Impacts of multiple stressors on ecosystem function: Leaf decomposition in constructed urban wetlands. (United States)

    Mackintosh, Teresa J; Davis, Jenny A; Thompson, Ross M


    The impact of stormwater on stream biota is well documented, but less is known about the impacts on ecosystem processes, such as the breakdown of organic matter. This study sought to establish whether the degree of urbanisation affected rates of leaf-litter breakdown within constructed wetlands. A litter bag method was used to ascertain rate of decomposition along a gradient of urbanisation (total imperviousness, TI), in constructed wetlands in western and south-eastern Melbourne. A significant positive relationship between TI and breakdown rate was found in the south-eastern wetlands. The significant reduction in rate of invertebrate-mediated breakdown with increasing concentration of certain metals was consistent with other studies. However, overall there was an increase in rate of breakdown. Studies have shown that the effects of heavy metals can be negated if nutrient levels are high. Our results suggest that other parameters besides exposure to contaminants are likely to affect leaf litter breakdown. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Robust biological nitrogen removal by creating multiple tides in a single bed tidal flow constructed wetland. (United States)

    Hu, Yuansheng; Zhao, Yaqian; Rymszewicz, Anna


    Achieving effective total nitrogen (TN) removal is one of the major challenges faced by constructed wetlands (CWs). To address this issue, multiple "tides" were proposed in a single stage tidal flow constructed wetland (TFCW). With this adoption, exceptional TN removal (85% on average) was achieved under a high nitrogen loading rate (NLR) of around 28 g Nm(-2)day(-1), which makes the proposed system an adequate option to provide advanced wastewater treatment for peri-urban communities and rural area. It was revealed that the multiple "tides" not only promoted TN removal performance, but also brought more flexibility to TFCWs. Adsorption of NH4(+)-N onto the wetland medium (during contact period) and regeneration of the adsorption capacity via nitrification (during bed resting) were validated as the key processes for NH4(+)-N conversion in TFCWs. Moreover, simultaneous nitrification denitrification (SND) was found to be significant during the bed resting period. These findings will provide a new foundation for the design and modeling of nitrogen conversion and oxygen transfer in TFCWs. © 2013.

  11. Kinetic and mass balance analysis of constructed wetlands treating landfill leachate. (United States)

    Sawaittayothin, V; Polprasert, C


    Experiments were conducted to investigate the feasibility of applying constructed wetlands to treat a sanitary landfill leachate containing high nitrogen (TN) and bacterial contents. Two-pilot scale subsurface-flow constructed wetland (SFCW) units located at the Asian Institute of Technology, Thailand, campus, were fed with a synthetic wastewater and landfill leachate collected from a nearby sanitary landfill. Under the tropical conditions (temperature of about 30 degrees C), the SFCW units operating at the hydraulic retention time(HRT) of 8 days yielded the best treatment efficiencies with BOD, removal of 91%, TN removal of 96%, total and fecal coliforms (TC and FC) removal of more than 99% and cadmium removal of 99.7%. The treatment performance was found to follow first-order reaction rate, in which the k20 values of BOD5, COD, TN, TC, FC and Cd were 0.201, 0.121, 0.247, 0.346, 0.354 and 0.690 d(-1), respectively. Mass balance analysis, based on TN contents of the plant biomass and dissolved oxygen (DO) and oxidation- reduction potential (ORP) values, suggested that 88% of the input TN were uptaken by the plant biomass; 8% removed by nitrification-denitrification reactions and adsorption on the wetland media, while the remaining 4% were discharged with the effluent.

  12. [Treatment of 1, 2-dichlorobenzene in wastewater by using horizontal subsurface flow constructed wetlands]. (United States)

    Ding, Cheng; Yang, Tang-Yi; Yu, Qian; Li, Zhao-Xia; Yang, Chun-Sheng


    Pilot-scale horizontal subsurface flow constructed wetlands (SFCW) planted with Phragmites australis were constructed to treat in 1,2-dichlorobenzene (o-DCB) wastewater. Different soil substrates of loam (W-L), fine sand (W-F) and coarse sand (W-C) were used in the three SFCW and a loam wetland with no reeds W-Z was taken as control. Results showed that the optimal hydraulic retention time (HRT) and pollutants surface loading rate(ALR)were 5 d and 150 mg x (m2 x d)(-1). Removal efficiencies for o-DCB of W-L, W-F, W-C and W-Z were 81.2%, 71.1%, 72.4% and 65.2%, respectively. The performance of systems achieved in mid-August and declined from October, with order of W-L > W-C > W-Z > W-F. Spatial concentration dynamics of o-DCB and dissolved oxygen (DO) were also investigated in W-L and W-Z, which indicated that DO was an important role to removal of o-DCB. The residual quantity of o-DCB in wetland substrate decreased along the flow direction and increased with the depth of substrate layers, the mean residual in the root, stem and leaf of reeds were 30.28, 14.85 and 6.18 microg x g(-1).

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

    Energy Technology Data Exchange (ETDEWEB)

    Maltais-Landry, Gabriel [Departement des sciences biologiques, Universite de Montreal 90, rue Vincent-D' Indy, Montreal (Ciheam), H2V 2S9 (Canada); Institut de recherche en biologie vegetale, Universite de Montreal 4101, rue Sherbrooke Est, Montreal (Ciheam), H1X 2B2 (Canada)], E-mail:; Maranger, Roxane [Departement des sciences biologiques, Universite de Montreal 90, rue Vincent-D' Indy, Montreal (Ciheam), H2V 2S9 (Canada)], E-mail:; Brisson, Jacques [Departement des sciences biologiques, Universite de Montreal 90, rue Vincent-D' Indy, Montreal (Ciheam), H2V 2S9 (Canada); Institut de recherche en biologie vegetale, Universite de Montreal 4101, rue Sherbrooke Est, Montreal (Ciheam), H1X 2B2 (Canada)], E-mail:; Chazarenc, Florent [Institut de recherche en biologie vegetale, Universite de Montreal 4101, rue Sherbrooke Est, Montreal (Ciheam), H1X 2B2 (Canada)


    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{sub 2}O), carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) production in CW mesocosms over three seasons. CW emitted 2-10 times more GHG than natural wetlands. Overall, CH{sub 4} was the most important GHG emitted in unplanted treatments. Oxygen availability through artificial aeration reduced CH{sub 4} fluxes. Plant presence also decreased CH{sub 4} fluxes but favoured CO{sub 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. - Methane is the main greenhouse gas produced in constructed wetlands and oxygen availability is the main factor controlling fluxes.

  14. Pre-Construction Biogeochemical Analysis of Mercury in Wetlands Bordering the Hamilton Army Airfield (HAAF) Wetlands Restoration Site. Part 2

    National Research Council Canada - National Science Library

    Best, Elly P; Fredrickson, Herbert L; Hintelmann, Holger; Clarisse, Olivier; Dimock, Brian; Lutz, Charles H; Lotufo, Gui R; Millward, Rod N; Bednar, Anthony J; Furey, John S


    ...) is working with the San Francisco Basin Regional Water Board, California State Coastal Conservancy, and San Francisco Bay Conservation and Development Commission to reconstruct wetlands at the former...

  15. Thermal analysis of wood-steel hybrid construction


    Fonseca, E.M.M.; Ramos, H.M.E.; Silva, H.J.G.; Ferreira, Débora


    The main objective of this work is to provide the thermal analysis in wood-steel hybrid elements for building constructions under fire conditions. A transient thermal analysis with nonlinear material behaviour will be solved with ANSYS program. The use of wood-steel hybrid models has major advantages as increased fire resistance, and improved high strength. Wood is a lightweight material, easy to assemble, great architectural features, thermal and acoustic characteristics. However, the high v...

  16. A review of a recently emerged technology: Constructed wetland--Microbial fuel cells. (United States)

    Doherty, Liam; Zhao, Yaqian; Zhao, Xiaohong; Hu, Yuansheng; Hao, Xiaodi; Xu, Lei; Liu, Ranbin


    Constructed wetlands (CWs) and microbial fuel cells (MFCs) are compatible technologies since both are reliant on the actions of bacteria to remove contaminants from wastewater. MFCs require the anode to remain anaerobic with the cathode exposed to oxygen while these redox conditions can develop naturally in CWs. For this reason, research into combining the two technologies (termed as CW-MFC) has emerged in recent years with the aim of improving the wastewater treatment capacity of wetlands while simultaneously producing electrical power. Based on the published work (although limited), this review aims to provide a timely, current state-of-the-art in CW-MFC while exploring future challenges and research directions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Evaluation of an integrated constructed wetland to manage pig manure under Mediterranean climate. (United States)

    Nehmtow, Julie; Rabier, Jacques; Giguel, Raphaël; Coulomb, Bruno; Farnet, Anne Marie; Perissol, Claude; Alary, Arnaud; Laffont-Schwob, Isabelle


    Pig manure is a complex mixture with excessive nutrients such as ammonium, microbial pathogens and may contain contaminants such as antibiotics. Conventional pig manure management practices caused water contamination. Sludge treatment wetland has been evaluated to determine its potential use under Mediterranean climate aiming at a parsimonious use of water and preventing water contamination, two major steps to preserve water resources in the Mediterranean Basin. Preliminary NH4-N degradation was tested using aeration process and/or addition of commercial bacterial products. Aeration alone appeared to be sufficient to ensure nitrogen transformation of the pig manure at lab small-scale (10 L) and medium-scale (300 L). Selected plant species e.g., Carex hispida for use in the integrated constructed wetland tolerated the nitrogen content after aeration enabling their use in a treatment vertical bed.

  18. System design and treatment efficiency of a surface flow constructed wetland receiving runoff impacted stream water. (United States)

    Maniquiz, M C; Choi, J Y; Lee, S Y; Kang, C G; Yi, G S; Kim, L H


    This study reported the efficiency of a free water surface flow constructed wetland (CW) system that receives runoff impacted stream water from a forested and agricultural watershed. Investigations were conducted to examine the potential effect of hydraulic fluctuations on the CW as a result of storm events and the changes in water quality along the flow path of the CW. Based on the results, the incoming pollutant concentrations were increased during storm events and greater at the near end of the storm than at the initial time of storm. A similar trend was observed to the concentrations exiting the CW due to the wetland being a relatively small percentage of the watershed (time during storm events. The concentrations of most pollutants were significantly reduced (p retention of most pollutants during storm events as the actual water quality of the outflow was significantly better by 21-71% than the inflow and the levels of pollutants were reduced to appreciable levels.

  19. Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading.

    Directory of Open Access Journals (Sweden)

    Guangwei Yu

    Full Text Available 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.

  20. Bacterial phylogenetic diversity in a constructed wetland system treating acid coal mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nicorarat, D.; Dick, W.A.; Dopson, M.; Tuovinen, O.H. [Ohio State University, Columbus, OH (USA)


    Microorganisms in acid mine drainage are typically acidophiles that mediate the oxidation of reduced compounds of iron and sulfur. However, microbial populations in wetland systems constructed to treat acid mine drainage are not well characterized. This study was to analyze bacterial diversity, using cultivation-independent molecular ecological techniques, in a constructed wetland that received acid drainage from an abandoned underground coal mine. DNA was purified from Fe(III)-precipitates from the oxidized surface zone of wetland sediments and 16S rRNA gene sequences were amplified and cloned. A total of 200 clones were analyzed by restriction fragment length polymorphism (RFLP) and 77 unique RFLP patterns were obtained with four restriction enzymes. Of these patterns, 30 most dominant unique clones were selected for sequencing of their 16S rRNA genes. Half of these 30 clones could be matched with autotrophic iron- and sulfur-oxidizing bacteria (Acidithiohacillus ferrooxidans and Acidithiobacillus thiooxidans). Several clones also formed a clade with heterotrophic iron-oxidizing bacteria (TRA2-10, TRA3-20, and TRA5-3) and heterotrophic bacteria (Stenotrophomas maltophilia, Bordetella spp., Alcalgenes sp., Alcaligenesfaecalis, and Alcaligenes xylosoxidans). Approximately 40% and 35% of the analyzed RFLP restriction patterns were consistent with A. ferrooxidans and A. thiooxidans, respectively. The relatively high frequency of acidithiobacilli is consistent with the chemical and physical characteristics of this site i.e., continuous, abundant supply of reduced iron and sulfur compounds, pH 3-4, ambient temperature, and limited organics originating from the coal seam and from vegetation or soil surrounding the inlet channel to the wetland.

  1. Constructing wetlands: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material (United States)

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


    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.

  2. Removing filterable reactive phosphorus from highly coloured stormwater using constructed wetlands. (United States)

    Lund, M A; Lavery, P S; Froend, R F


    A constructed wetland design, consisting of 16 repeating cells was proposed for Henley Brook (Perth, Western Australia) to optimise the removal of FRP from urban stormwater. Three replicate experimental ponds (15 x 5 m), were constructed to represent at a 1:1 scale a single cell from this design. Three 5 m zones of each pond were sampled: shallow (0.3 m) vegetated (Schoenoplectus validus) inflow and outflow zones and a deeper (1 m), V-shaped central zone. In 1998/99, inflows and outflow waters were intensively sampled and analysed for FRP and Total P. In addition, all major pools of P (plants, sediment) within the ponds, and important P removal processes (benthic flux, uptake by biofilm and S. validus) were quantified. A removal efficiency of 5% (1998) and 10% (1999) was obtained for FRP. Initial uptake was mainly in plant biomass, although the sediment became an increasingly important sink. Benthic flux experiments showed that anoxia did not cause release of P from sediments, indicating that most of the P was bound as apatite rather than associated with Fe or Mn. The highly coloured waters were believed responsible for the very low biofilm biomass recorded (<1 g x m(-2)). We have demonstrated that constructed wetlands can be effective for removing FRP immediately after construction, although their long-term removal capacity needs further research.

  3. Phytoremediation of Water Using Phragmites karka and Veteveria nigritana in Constructed Wetland. (United States)

    Badejo, Adedayo A; Sridhar, Mynepalli K C; Coker, Adewale O; Ndambuki, Julius M; Kupolati, Williams K


    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.

  4. Colonization of a newly constructed urban wetland by mosquitoes in England: implications for nuisance and vector species. (United States)

    Medlock, Jolyon M; Vaux, Alexander G C


    Urban wetlands are being created in the UK as part of sustainable urban drainage strategies, to create wetland habitats lost during development, to provide a habitat for protected species, and to increase the public's access to 'blue-space' for the improvement of health and well-being. Sewage treatment reedbeds are also being incorporated into newly constructed wetlands to offer an alternative approach to dealing with sewage. This field study aims to provide the first UK evidence of how such newly constructed aquatic habitats are colonized by mosquitoes. A number of new aquatic habitats were surveyed for immature mosquitoes every fortnight over the first two years following wetland construction. The majority of mosquitoes collected were Culex sp. and were significantly associated with the sewage treatment reedbed system, particularly following storm events and sewage inflow. Other more natural aquatic habitats that were subject to cycles of drying and re-wetting contributed the majority of the remaining mosquitoes colonizing. Colonization of permanent habitats was slow, particularly where fluctuations in water levels inhibited emergent vegetation growth. It is recommended that during the planning process for newly constructed wetlands consideration is given on a case-by-case basis to the impact of mosquitoes, either as a cause of nuisance or as potential vectors. Although ornithophagic Culex dominated in this wetland, their potential role as enzootic West Nile virus vectors should not be overlooked. © 2014 The Society for Vector Ecology.

  5. Establishing a design for passive vertical flow constructed wetlands treating small sewage discharges to meet British Standard EN 12566. (United States)

    Weedon, Christopher Michael; Murphy, Clodagh; Sweaney, Geoff


    Owing to legislation change (which made General Binding Rules effective from 1 January 2015) unless discharge is to specified environmentally sensitive sites, small sewage discharges (SSDs) in England - that is, wetlands, unless covered by an EP, because the cost of certification to EN 12566 for bespoke designs is prohibitive. EPs take up to four months to obtain. Therefore, the new legislation has created a commercial disadvantage for constructed wetlands treating SSDs, compared with mass-produced sewage treatment plants. However, the UK statutory pollution regulators have maintained a dialogue with the Constructed Wetland Association (CWA), with a view to assessing whether treatment of SSD using constructed wetlands might be allowable, without requiring EPs. This paper presents treatment performance data obtained over 15 years, from a variety of full-scale operational treatment wetlands, as supporting evidence for design guidelines, proposed by the CWA to the UK regulators, for the implementation of constructed wetlands continuously passively treating SSD to 20:30:20 mg l-1 BOD/SS/NH4-N under a wide range of loading rates. Relevant experience of UK designers, installers and operators since the early 1990s is included, resulting in recommended physical design criteria and loading rates for compact vertical flow reed beds, presented here as key elements of the draft guidelines.

  6. Correlation Among Soil Enzyme Activities, Root Enzyme Activities, and Contaminant Removal in Two-Stage In Situ Constructed Wetlands Purifying Domestic Wastewater. (United States)

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


    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.

  7. Performance comparison of constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen removal. (United States)

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


    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.

  8. Site characterization for hybrid system construction

    Energy Technology Data Exchange (ETDEWEB)

    Saldana, R.; Miranda, U.; Medrano, M. C. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)


    The basic reason to use alternative systems for electricity generation, in most cases, is the lack of electricity services, such as isolated rural communities which are located far away from the electric distribution line, and the cost of its extension is too expensive, while decentralized power systems can be an economic and appropriate solution to providing these services. Up to now there are several technological options for rural electrification using PV modules, wind plants, water-power plants, anaerobic digesters, or a combination of some of them, according to the availability of energetic resources. The applications include centralized or decentralized systems, autonomous or hybrid systems, isolated or interconnected to the electric line, etc. A particular hybrid system design can be done considering two general aspects, first it is necessary to know the electric consumption that will be supplied, taking into account present and future necessities and how local energetic resources are present in a selected site. Finally, also it is necessary to carry out an economic analysis to determine the cost of kilowatt-hour generated using local energetic resources and compare it with the cost of electricity produced by conventional power systems. [Espanol] La razon principal para el uso de sistemas alternativos de generacion de electricidad, en la mayoria de los casos, es la falta de servicios de electricidad, tal como en las comunidades rurales aisladas localizadas lejos de linea de distribucion electrica, donde el costo de su extension es demasiado caro, mientras que los sistemas descentralizados de energia pueden ser una solucion economica y adecuada para proporcionar estos servicios. Hasta ahora existen varias opciones tecnologicas para la electrificacion rural usando modulos fotovoltaicos, aerogeneradores, plantas hidroelectricas, digestores anaerobicos o una combinacion de algunos de ellos, de acuerdo con la disponibilidad de los recursos energeticos. Las

  9. Design and performance of a pilot-scale constructed wetland treatment system for natural gas storage produced water. (United States)

    Kanagy, Laura E; Johnson, Brenda M; Castle, James W; Rodgers, John H


    To test the hypothesis that water produced from natural gas storage wells could be treated effectively by constructed wetland treatment systems, a modular pilot-scale system was designed, built, and used for treating gas storage produced waters. Four simulated waters representing the range of contaminant concentrations typical of actual produced waters were treated, and the system's performance was monitored. Freshwater wetland cells planted with Schoenoplectus californicus and Typha latifolia were used to treat fresh and brackish waters. Saline and hypersaline waters were treated by saltwater wetland cells planted with Spartina alterniflora and by reverse osmosis. Effective removal of cadmium, copper, lead, and zinc was achieved by the pilot-scale system. Results suggest that use of specifically designed constructed wetland treatment systems provides a flexible and effective approach for treating gas storage produced waters over a wide range of compositions.

  10. Limestone and Zeolite as Alternative Media in Horizontal Subsurface Flow Constructed Wetlands: Laboratory-Scale Studies (United States)

    Lizama, K.; Jaque, I.; Ayala, J.


    Arsenic is well known for its chronic toxicity. Millions of people around the world are currently at risk, drinking water with As concentrations above 10 ppb, the WHO drinking water guideline. Although different treatment options exist, they are often limited by elevated costs and maintenance requirements. Constructed wetlands are a natural water treatment system, capable to remove metals and metalloids -including As- via different physical, chemical and biological processes. The use of alternative supporting media to enhance As removal in subsurface flow wetlands has been recommended, but not sufficiently studied. Limestone and zeolite have been identified as effective supporting media in subsurface flow wetlands aiming As removal. However, there are still key aspects to be addressed, such as the implications of using these media, the speciation in the solid phase, the role of vegetation, etc. This study investigated the performance of limestone and zeolite in three types of experiments: batch, column and as main supporting media in a bench scale horizontal subsurface flow wetland system. Synthetic water resembling a contaminated river in Chile (As concentration=3 mg/L, Fe concentration= 100 mg/L, pH=2) was used in all experiments. In the batch experiments, the As concentration, the mass of media and the contact time were varied. The column system consisted of three limestone columns and three zeolite columns, operated under a hydraulic loading of 20 mm/d. The wetland system consisted of twelve PVC cells: six filled with zeolite and six with limestone. Phragmites australis were planted in three cells of each media type, as control cells. From the batch experiments, maximum As sorption capacities as indicated by Langmuir model were 1.3 mg/g for limestone and 0.17 mg/g for zeolite, at 18 h contact time and 6.3 g/L medium concentration. EDS and XPS analyses revealed that As and Fe were retained in zeolite at the end of the batch experiments. Zeolite and limestone

  11. Removal of cypermethrin from cattle bath by using constructed wetland system

    Directory of Open Access Journals (Sweden)

    José Luis Marrugo Negrete


    Full Text Available Ectoparasite control in the livestock sector involves the use of chemicals to prevent production losses. In small farms that produce milk in the Córdoba department, the use of the pumping system for the cattle bath is common between farmers. In this work, cypermethrin degradation efficiency was evaluated in three lab-scale subsurface flow constructed wetland planted with Limnocharis flava, Cyperus papyrus and Alpinia purpurata sp., and one unplanted system, all of the beds were gravel based; then, total suspended solids and total phosphorus retention, and elimination of chemical oxygen demand were measured as water quality parameters. The wastewater was pretreated in a descending-ascending slow sand filter, and then was conducted to a wetland continuous flow fed at 7 ml/min. Limnocharis flavabed was higher for the degradation of organic compounds, with 97.9 ± 2.5 % and 69.1 ± 3.7 % for cypermethrin and chemical oxygen demand respectively, with statistically significant differences (p < 0,05 respect to unplanted bed. The higher SST removal were found in the Cyperus papyruswetland, with 62,0 %, however, no differences were observed with the other evaluated planted systems, as opposed these were significantly higher than unplanted wetlands.

  12. Clogging of vertical-flow constructed wetlands treating urban wastewater contaminated with a diesel spill. (United States)

    Al-Isawi, Rawaa; Scholz, Miklas; Wang, Yu; Sani, Abdulkadir


    Clogging often leads to a decrease of the treatment performance of wetlands. The aims of this study were to compare the impact of different design and operational variables on the treatment efficiency and clogging processes and to model suspended solid (SS) accumulation within the saturated wetland zone using the Wang-Scholz model. Different vertical-flow constructed wetlands were operated from June 2011 until April 2014. Four treatment periods were assessed: set-up, first year after set-up period, second year after set-up period and diesel spill (for selected filters only). The filter with the highest chemical oxygen demand (COD) loading but no diesel contamination performed the best in terms of COD and biochemical oxygen demand (BOD) removal for the fourth and final treatment period. Filters contaminated by diesel performed worse in terms of COD and BOD but considerably better regarding nitrate-nitrogen removal. Serious clogging phenomena impacting negatively on the treatment performance and the hydraulic conductivity were not observed. Modelling results were generally poor for the set-up period, adequate for the first 2 years after the set-up period and variable after the diesel spill. The Wang-Scholz model performed well for less complex operations.

  13. Performance evaluation of a constructed wetland treating high-ammonium primary domestic wastewater effluent. (United States)

    Spokas, L A; Veneman, P L M; Simkins, S C; Long, S C


    An investigation of a top-loading, vertical-flow, submerged-bed constructed wetland system subject to a New York State discharge permit, of mineral nitrogen transformations occurring within the wetland units, and of the effects of local environment on system performance indicated 100% removal of biochemical oxygen demand (BOD) and mean 99.0 +/- 1.1% removal of ammonium (NH4(+)). The wetland system, located in Highland, New York, treats primary domestic wastewater effluent and consists of four beds presently operated in series. Influent and effluent samples from each of the four treatment units were analyzed for BOD, ammonium-nitrogen (NH4(+)-N), nitrate-nitrogen (NO3(-)-N), and nitrite-nitrogen (NO2(-)-N). During the study, mean influent wastewater concentrations were 170.8, 3.1, and 0.015 mg/L for NH4(+)-N, NO3(-)-N, and NO2(-)-N, respectively. Mean effluent concentrations of NH4(+)-N, NO3(-)-N, and NO2(-)-N were 1.9, 4.2, and 0.002 mg/L, respectively.

  14. Microbial density and diversity in constructed wetland systems and the relation to pollutant removal efficiency. (United States)

    Zhang, Yang; Carvalho, Pedro N; Lv, Tao; Arias, Carlos; Brix, Hans; Chen, Zhanghe


    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.

  15. Performance of pilot-scale constructed wetlands for secondary treatment of chromium-bearing tannery wastewaters. (United States)

    Dotro, Gabriela; Castro, Silvana; Tujchneider, Ofelia; Piovano, Nancy; Paris, Marta; Faggi, Ana; Palazolo, Paul; Larsen, Daniel; Fitch, Mark


    Tannery operations consist of converting raw animal skins into leather through a series of complex water- and chemically-intensive batch processes. Even when conventional primary treatment is supplemented with chemicals, the wastewater requires some form of biological treatment to enable the safe disposal to the natural environment. Thus, there is a need for the adoption of low cost, reliable, and easy-to-operate alternative secondary treatment processes. This paper reports the findings of two pilot-scale wetlands for the secondary treatment of primary effluents from a full tannery operation in terms of resilience (i.e., ability to produce consistent effluent quality in spite of variable influent loads) and reliability (i.e., ability to cope with sporadic shock loads) when treating this hazardous effluent. Areal mass removal rates of 77.1 g COD/m2/d, 11 g TSS/m2/d, and 53 mg Cr/m2/d were achieved with a simple gravity-flow horizontal subsurface flow unit operating at hydraulic loading rates of as much as 10 cm/d. Based on the findings, a full-scale wetland was sized to treat all the effluent from the tannery requiring 68% more land than would have been assumed based on literature values. Constructed wetlands can offer treatment plant resilience for minimum operational input and reliable effluent quality when biologically treating primary effluents from tannery operations. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. The performance of constructed wetlands treating primary, secondary and dairy soiled water in Ireland (a review). (United States)

    Healy, M G; O' Flynn, C J


    In Ireland, no database detailing the design, influent loading rates or performance of constructed wetlands (CWs) exists. On account of this, they are designed without any protocol based on empirical data. The aim of this paper was to provide the first published data on the performance of free-water surface flow (FWSF) CWs treating primary and secondary-treated municipal wastewater, and agricultural dairy soiled water (DSW) in Ireland. In total, the performance of thirty-four FWSF CWs, comprising fourteen CWs treating primary-treated municipal wastewater, thirteen CWs treating secondary-treated municipal wastewater, and seven CWs treating DSW, were examined. In most CWs, good organic, suspended solids (SS) and nutrient removal was measured. At an average organic loading rate (OLR) of 10 and 9 g biochemical oxygen demand (BOD) m(-2) d(-1), CWs treating primary and secondary wastewater removed 95 and 84% of influent BOD. Constructed wetlands treating DSW had an average BOD removal of 98%. At average SS loading rates of 6 and 14 g m(-2) d(-1), CWs treating primary and secondary wastewater had a 96 and an 82% reduction, and produced a final effluent with a concentration of 14 and 13 mg L(-1). Constructed wetlands treating DSW produced a final effluent of 34 mg L(-1) (94% reduction). Similar to other studies, all CWs examined had variable performance in ammonium-N (NH(4)(+)-N) removal, with average removals varying between 37% (for CWs treating secondary wastewater) and 88% (for CWs treating DSW). Variable ortho-phosphorus (PO(4)(3-)-P) removal was attributable to different durations of operation, media types and loading rates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Influence of clogging and resting processes on flow patterns in vertical flow constructed wetlands. (United States)

    Hua, Guofen; Kong, Jun; Ji, Yuyu; Li, Man


    Vertical flow constructed wetlands are widely used for removing pollutants from wastewater. Substrate clogging is an operational challenge of constructed wetlands, which can result in impeded water flow and finally a significant decline in the ability of the system to treat the wastewater. The entire clogging process in a vertical flow constructed wetland (VFCW) was quantitatively analyzed by measurements of hydraulic conductivity. Tracer tests and model simulations were carried out to investigate internal flow patterns during the clogging and resting processes. This analysis revealed that hydraulic conductivity gradually decreased with operation time. Further, the distribution time of the flow field was different under different degrees of clogging. Non-uniformity in water flow was primarily observed in the first 400min after adding the tracer (NaCl) in the early clogging stage, as opposed to the last 400min in the late clogging stage. Variation in water flow divergence was closely correlated with piston flow; the reaction efficiency was highest in the early stages of clogging. In the later stages, stronger flow mixing was observed. Resting operations can reduce the dispersion of internal flow and improve reaction efficiency. After resting for approximately 15days, tracer concentration fluctuations decreased and internal flow back-mixing was alleviated. A simulation further described the internal flow pattern and elaborated and validated the tracer experiment. The outcomes of this study will assist in understanding how internal flow behavior varies in response to the clogging process and reveal details of the internal clogging mechanism in VFCWs. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Sulphate reduction and the removal of carbon and ammonia in a laboratory-scale constructed wetland. (United States)

    Wiessner, A; Kappelmeyer, U; Kuschk, P; Kästner, M


    Sulphate is a normal constituent of domestic wastewater and reduced sulphur compounds are known to be potent inhibitors of plant growth and certain microbial activities. However, the knowledge about sulphate reduction and the effect on the removal of C and N in constructed wetlands is still limited. Investigations in laboratory-scale constructed wetland reactors were performed to evaluate the interrelation of carbon and nitrogen removal with the sulphate reduction by use of artificial domestic wastewater. Carbon removal was found to be only slightly affected and remained at high levels of efficiency (75-90%). Only at sulphate reduction intensities above 75 mgl(-1) (50% removal), a decrease of carbon removal of up to 20% was observed. A highly contrary behaviour of ammonia removal was found in general, which decreased exponentially from 75% to 35% related to a linear increase of sulphate reduction up to 75 mgl(-1) (50% removal). Since sulphate removal is considered to be dependant on the load of electron donors, the carbon load of the system was varied. Variation of the load changed the intensities of sulphate reduction immediately, but did not influence the carbon removal effectiveness. Doubling of the carbon concentration of 200 mgl(-1) BOD(5) for domestic wastewater usually led to sulphate reduction of up to 150 mgl(-1) (100% removal). The findings show that, particularly in constructed wetland systems, the sulphur cycle in the rhizosphere is of high importance for performance of the waste water treatment and may initiate a reconsideration of the amount of sulphate present in the tap water systems.

  19. Assessment of low concentration wastewater treatment operations with dewatered alum sludge-based sequencing batch constructed wetland system


    Kang, Wei; Chai, Hongxiang; Xiang, Yu; Chen, Wei; Shao, Zhiyu; He, Qiang


    Competition of volatile fatty acids between anoxic denitrification and anaerobic phosphorus release is prominent. Therefore, low concentration wastewater has restricted effects on nitrogen and phosphorus removal. The purpose of this study is to treat dormitory sewage with a biochemical oxygen demand (BOD) ranging from 50 to 150 mg/L using dewatered alum sludge-based sequencing batch constructed wetland system. Vegetation in the wetland system was chosen to be Phragmites australis. Three paral...

  20. Agronomic performance of black oat (Avena strigosa Schreb.), cultivated in constructed wetlands


    Alisson Carraro Borges; Lidiane Carvalho de Campos; Antonio Teixeira de Matos; Valdeir Eustáquio Júnior


    This work aimed to evaluate the agronomic performance of black oat (Avena strigosa Schreb.), when cultived in constructed wetlands (CWs) in the treatment of domestic wastewater. The experiment was conducted in four CWs for secondary/tertiary treatment of domestic wastewater. The black oats were sown in the CWs at a density of 80 kg ha-1 of seeds. The organic loading rates (OLRs) applied in the CWs were 100, 200, 400 and 600 kg ha-1 d-1 of biochemical oxygen demand (BOD). The OLRs were obtaine...

  1. Removal Kinetics of Organic Matter and Nitrogen Using Microbial Electrochemical Based - Constructed Wetlands (iMETland)

    DEFF Research Database (Denmark)

    Ramírez Vargas, Carlos Andrés; Arias, Carlos Alberto; Carvalho, Pedro

    In recent years the combination of Constructed Wetlands and Microbial Fuel Cell (MFC), has led to an innovative set- up for wastewater treatment and energy harvesting, relaying on electrodes and external circuits (CW – MFC). Based on this approach, a new concept is being developed to create....... The iMETland technology is still in development and therefore uncertainties still exist regarding the dynamics in the removal of pollutants, as well as in its performance along time. To elucidate these uncertainties, a benchmark study is being conducted to characterize the processes and interactions n...



    Eri Setiadi; Lies Setijaningsih


    Organic and inorganic pollutants such as N, P, and heavy metals are a serious problem in water bodies (lake, reservoir, river, and stream) and have deleterious effects to pond productivity and human health. These pollutants produced from anthropogenic activities (i.e. industrial, agricultural, and settlement) are released into the water bodies and causing poor water quality. Constructed wetland (CW) is one of the technologies that have the capability to solve such problems. The purpose of thi...

  3. Removal of emerging organic pollutants in constructed wetlands: imazalil and tebuconazole as model pesticides

    DEFF Research Database (Denmark)

    Lyu, Tao


    on aquatic environment and human health. Constructed wetland systems (CWs) have been an economical, robust and sustainable technology for wastewater treatment, and are emerging for the treatment of pesticides contaminated water. However, excluding the studies on pesticides removal efficiency, the research...... model pesticides imazalil and tebuconazole under different CWs designs with various operation strategies. The results showed that CWs can be applied to efficiently treat imazalil and tebuconazole contaminated wastewater. The pesticides removal in CWs can be adequate described by first order kinetics...... of CWs for pesticides treatment....

  4. Removal of Chlorinated Resin and Fatty Acids from Paper Mill wastewater through Constructed Wetland


    Ashutosh Kumar Choudhary; Satish Kumar; Chhaya Sharma


    This study evaluates the performance of horizontal subsurface flow constructed wetland (HSSF-CW) for the removal of chlorinated resin and fatty acids (RFAs) from pulp and paper mill wastewater. The dimensions of the treatment system were 3.5 m x 1.5 m x 0.28 m with surface area of 5.25 m2, filled with fine sand and gravel. The cell was planted with an ornamental plant species Canna indica. The removal efficiency of chlorinated RFAs was in the range of 92-96% at the hydrau...

  5. Vertical flow constructed wetlands for domestic wastewater treatment on tropical conditions: effect of several design parameters

    DEFF Research Database (Denmark)

    Bohorquez, Eliana; Paredes, Diego; Arias, Carlos Alberto

    Vertical flow constructed wetlands (VFWC) design and operation takes into account several variables which affect performance its performance. These aspects had been evaluated and documented among others in countries like USA, Denmark, Austria. In contrast, VFCW had not been studied in tropical...... countries and, specifically in Colombia, design and operation parameters are not defined yet. The objective of this study was evaluate the effects of filter medium, the feeding frequency and Heliconia psittacorum presence, a typical local plant, on the domestic wastewater treatment in tropical conditions....

  6. Construction and analysis of subtractive hybridization library of ...

    African Journals Online (AJOL)

    Eightweek- old C57BL/6 and A/J mouse were infected with S. suis serotype 2, a 200-μL volume of a bacterial suspension (1 × 108 CFU/mL) was administrated by intraperitoneal injection to the mice, and cDNA subtraction libraries were constructed by suppression subtraction hybridization (SSH). Genes involved in immune ...

  7. Area Estimation and Distribution Analysis of Subsurface Flow Constructed Wetlands at Regional Scale--Take Guangzhou City for Example (United States)

    Yuan, S. X.; Tang, G. L.; Xiong, H. X.; Chen, J.; Yin, X. L.; Huang, G. Q.


    In this paper, Area of Constructed Wetlands (CWs) required for treatment of domestic sewage generated by 13 million people was calculated in accordance with the distribution of existing population in Guangzhou City and mathematical model of CWs. By comparing this with land use data, the distribution of constructed wetlands at construction regional scale was simulated with GIS. The results show that, Guangzhou generate about 3.88 million m3 domestic sewage per day, which shall be treated with 59.37 km2 CWs. Assuming that a single wetland bed is 300 m2, total 197,905 wetland beds shall be required in the city. Based on the analysis and statistics on data of second national land survey of Guangzhou City with GIS, there are enough ponds, bare lands, other grasslands and other garden plots in Guangzhou that can be used for construction of regional scale CWs, but the distribution of available lands in different regions is uneven. Constructed wetlands at regional scale are mainly distributed around Baini Channel, Tianma River, Xinjie River, Liuxi River Valley, Zengjiang River Valley and on both sides of the Pearl River through Panyu and Nansha.


    Dual isotope evaluations of NO3 in groundwater adjacent to ditches within constructed riparian wetlands across the Kankakee water-shed may assist the determination of denitrification efficiency. Groundwater sampling indicates the NO3 -N exceeded 10 mg 1-1 in constructed riparian ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Apfelbaum, Steven L. [Applied Ecological Services Inc., Brodhead, WI (United States); Duvall, Kenneth W. [Sterling Energy Services, LLC, Atlanta, GA (United States); Nelson, Theresa M. [Applied Ecological Services Inc., Brodhead, WI (United States); Mensing, Douglas M. [Applied Ecological Services Inc., Brodhead, WI (United States); Bengtson, Harlan H. [Sterling Energy Services, LLC, Atlanta, GA (United States); Eppich, John [Waterflow Consultants, Champaign, IL (United States); Penhallegon, Clayton [Sterling Energy Services, LLC, Atlanta, GA (United States); Thompson, Ry L. [Applied Ecological Services Inc., Brodhead, WI (United States)


    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

  10. Optimal conditions for chlorothalonil and dissolved organic carbon in horizontal subsurface flow constructed wetlands. (United States)

    Rìos-Montes, Karina A; Casas-Zapata, Juan C; Briones-Gallardo, Roberto; Peñuela, Gustavo


    The most efficient system of horizontal subsurface flow constructed wetlands (HSSFCW) for removing dissolved organic carbon (DOC) in the presence of chlorothalonil pesticide (CLT) present in synthetic domestic wastewater was determined using the macrophyte Phragmites australis. Two concentrations of CLT (85 and 385 μg L-1) and one concentration of glucose (20 mg L-1) were evaluated in four pilot scale horizontal surface flow constructed wetlands coupled with two sizes of silica gravel, igneous gravel, fine chalky gravel (3.18-6.35 mm), coarse gravel (12.70-25.40 mm) and two water surface heights (20 and 40 cm). For a month, wetlands were acclimated with domestic wastewater. Some groups of bacteria were also identified in the biofilm attached to the gravel. In each treatment periodic samplings were conducted in the influent and effluent. Chlorothalonil was quantified by gas chromatography (GC-ECD m), DOC by an organic carbon analyzer and bacterial groups using conventional microbiology in accordance with Standard Methods. The largest removals of DOC (85.82%-85.31%) were found when using fine gravel (3.18-6.35 mm) and the lower layer of water (20 cm). The bacterial groups quantified in the biofilm were total heterotrophic, revivable heterotrophic, Pseudomonas and total coliforms. The results of this study indicate that fine grain gravel (3.18-6.35 mm) and both water levels (20 to 40 cm) can be used in the removal of organic matter and for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT in HSSFCW.

  11. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Eva M., E-mail: [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Kuschk, Peter; Fazekas, Helga [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Hoelderlinstr. 12, 72074 Tuebingen (Germany); Kaestner, Matthias [Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany)


    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{sup 2}/d, 97/112 mg/m{sup 2}/d, and 1167/1342 mg/m{sup 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. - Highlights: > BTEX compounds contaminated groundwater can be efficiently treated by CWs. > The removal efficiency depended on CW type, season and contaminant. > The plant root mat revealed better treatment results than the gravel filter CW. > Best results achieved by the plant root mat (99% benzene concentration decrease). > Stable isotope analysis and MPN indicated high benzene remediation potential. - Gravel bed constructed wetlands and a plant root mat system efficiently eliminated fuel hydrocarbons (benzene, MTBE) and ammonia-N from groundwater at a pilot-scale.

  12. Structure and function of the bacterial communities during rhizoremediation of hexachlorobenzene in constructed wetlands. (United States)

    Zhang, Cuiping; Wang, Bei; Dai, Xiaoyan; Li, Shuying; Lu, Guangqiu; Zhou, Yuanqing


    Vertical flow constructed wetlands (VF CWs) are considered to be effective for treating organic pollutants. The rhizosphere of macrophytes such as Phragmites sp., Typha sp. serves as an active and dynamic zone for the microbial degradation of organic pollutants. However, it is still not clear how soil bacterial communities respond to macrophytes and pollutants during the process. For this purpose, the seedlings of Phragmites australis and Typha angustifolia were planted respectively in the VF CWs added with HCB at a dose of 2 mg/kg. During 96 days of cultivation, we monitored hexachlorobenzene (HCB) removal efficiency by GC/MS and the structure of the rhizosphere bacterial communities in the different VF CWs by denaturing gradient gel electrophoresis (DGGE), and constructed bacterial clone library based on PCR-amplified 16S rRNA gene. As expected, the rhizosphere bacterial communities also remained insensitive to HCB exposure in the wetland soil. The diversity of these microbes presented two stages, from the varied up and down to equilibrium in the entire experimental period. Molecular analysis revealed that the phylum Firmicutes dominated over the bacterial communities. The genera that increased under HCB stress included the well-known HCB-degrading bacteria (Pseudomonas sp. and Alcaligenes sp.) and other common bacteria found in contaminated soil but with lesser known practical functions (Burkholderia sp., Lysinibacillus fusiformis, and Bacillus cereus). Furthermore, there was a certain variance in the relative abundances of the bacterial phyla and HCB removal efficiency among different VF CW treatments. The degradation of HCB in T. angustifolia microcosms was faster than that in P. australis and unvegetated wetlands, and the highest bacterial diversity and richness was found in the VF CWs comprising T. angustifolia.

  13. A lab-scale study of constructed wetlands with sugarcane bagasse and sand media for the treatment of textile wastewater. (United States)

    Saeed, Tanveer; Sun, Guangzhi


    This paper reports the pollutant removal efficiencies of two lab-scale hybrid wetland systems treating a textile wastewater. The two systems had identical configurations, each consisting of a vertical flow (VF) and a horizontal flow (HF) wetland that were filled with organic sugarcane bagasse and sylhet sand as the main media. The systems were operated under high hydraulic loading (HL) (566-5660 mm/d), and inorganic nitrogen (254-508 gN/m(2) d) and organics loadings (9840-19680 g COD/m(2) d and 2154-4307 g BOD(5)/m(2) d). Simultaneous removals of BOD(5) (74-79%) and ammonia (59-66%) were obtained in the first stage VF wetlands, demonstrating the efficiency of the media for oxygen transfer to cope with the high pollutant loads. The organic carbon (C) content of sugarcane bagasse facilitated denitrification in the VF wetlands. Second stage HF wetlands provided efficient color removal under predominantly anaerobic condition. Overall, the wetland systems showed stable removal performances under high, and unsteady, pollutant loadings. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. The adaptability of a wetland plant species Myriophyllum aquaticum to different nitrogen forms and nitrogen removal efficiency in constructed wetlands. (United States)

    Wang, Rui; Bai, Na; Xu, Shengjun; Zhuang, Guoqiang; Bai, Zhihui; Zhao, Zhirui; Zhuang, Xuliang


    Constructed wetlands (CWs) cultivated with Myriophyllum aquaticum showed great potential for total nitrogen (TN) removal from aquatic ecosystems in previous studies. To evaluate the growth characteristics, photosynthetic pigment content, and antioxidative responses of M. aquaticum, as well as its TN removal efficiency in CWs, M. aquaticum was treated with different levels of ammonium (NH4+) and nitrate (NO3-) for 28 days. The results indicated that M. aquaticum had strong nitrogen stress tolerance and was more likely to be suppressed by high levels of NH4+ than NO3-. High levels of NH4+ also led to inhibition of synthesis of photosynthetic pigments and increased peroxidase activity in plant leaves, which was not found in the NO3- treatments. High levels of both NH4+ and NO3- generated obvious oxidative stress through elevation of malondialdehyde content while decreasing superoxide dismutase activity in the early stage. A sustainable increase of TN removal efficiency in most of the CWs indicated that M. aquaticum was a candidate species for treating wastewater with high levels of nitrogen because of its higher tolerance for NH4+ and NO3- stress. However, the increase of TN removal efficiency was hindered in the late stage when treated with high levels of NH4+ of 26 and 36 mmol/L, indicating that its tolerance to NH4+ stress might have a threshold. The results of this study will enrich the studies on detoxification of high ammonium ion content in NH4+-tolerant submerged plants and supply valuable reference data for proper vegetation of M. aquaticum in CWs.

  15. Halophytes as vertical-flow constructed wetland vegetation for domestic wastewater treatment. (United States)

    Fountoulakis, M S; Sabathianakis, G; Kritsotakis, I; Kabourakis, E M; Manios, T


    Recent findings show that halophytes have the ability to accumulate salts in their tissues, making them a very interesting group of plants for domestic wastewater treatment in constructed wetlands (CWs). In that case, it might be possible to reduce the salinity of the final effluent, which is a crucial parameter for wastewater reuse in agriculture. During this study three halophytes, Atriplex halimus, Juncus acutus and Sarcocornia perennis, were tested for phyto-desalination of domestic wastewater in a vertical flow constructed wetland (VFCW) and compared with common reeds (Phragmites australis). In addition, the effect of this alternative vegetation on the overall performance of the system regarding organic matter, nutrients, boron and pathogen removal was monitored. The organic loading rate (OLR) was about 21gCOD/m2/d and the hydraulic loading rate (HLR) was 95mm/d in both cases. Promising results were obtained for A. halimus, which shows high biomass productivity and significant capability to accumulate salts, mainly Na, in its tissues. A positive effect on pathogen removal efficiency was also recorded. However, nitrogen concentration in the effluent of the VFCW planted with halophytes was found to be higher than in the effluent of the VFCW planted with reeds. Finally, no significant effect on organic matter and phosphorus removal efficiency was observed from the use of halophytes in place of reeds. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Treatment of Oil Wastewater and Electricity Generation by Integrating Constructed Wetland with Microbial Fuel Cell

    Directory of Open Access Journals (Sweden)

    Qiao Yang


    Full Text Available Conventional oil sewage treatment methods can achieve satisfactory removal efficiency, but energy consumption problems during the process of oil sewage treatment are worth attention. The integration of a constructed wetland reactor and a microbial fuel cell reactor (CW-MFC to treat oil-contaminated wastewater, compared with a microbial fuel cell reactor (MFC alone and a constructed wetland reactor (CW alone, was explored in this research. Performances of the three reactors including chemical oxygen demand (COD, oil removal, and output voltage generation were continuously monitored. The COD removals of three reactors were between 73% and 75%, and oil removals were over 95.7%. Compared with MFC, the CW-MFC with a MnO2 modified cathode produced higher power density and output voltage. Maximum power densities of CW-MFC and MFC were 3868 mW/m3 (102 mW/m2 and 3044 mW/m3 (80 mW/m2, respectively. The plants in CW-MFC play a positive role for reactor cathode potential. Both plants and cathode modification can improve reactor performance of electricity generation.

  17. Responses of phytoplankton and Hyalella azteca to agrichemical mixtures in a constructed wetland mesocosm. (United States)

    Lizotte, Richard E; Testa, Sam; Locke, Martin A; Steinriede, R Wade


    We assessed the capability of a constructed wetland to mitigate toxicity of a variety of possible mixtures, such as nutrients only (NO) (nitrogen [N], phosphorus [P]), pesticides only (PO) (atrazine, S-metolachlor, permethrin), and nutrients + pesticides on phytoplankton chlorophyll-a, on 48-h aqueous Hyalella azteca survival and 10-day sediment H. azteca survival and growth. Water and sediment were collected at 10-, 20-, and 40-m distances from inflow and analyzed for nutrients, pesticides, chlorophyll-a, and H. azteca laboratory bioassays. Phytoplankton chlorophyll-a increased 4- to 10 -fold at 7 days after NO treatment. However, responses of chlorophyll-a to PO and nutrients + pesticides were more complex with associated decreases at only 20 m for pesticides only and 10 and 40 m for nutrients + pesticides treatments. H. azteca aqueous survival decreased within the first 48 h of dosing at 10- and 20-m distances during PO and nutrients + pesticides treatments in association with permethrin concentrations. H. azteca sediment survival was unaffected, whereas 10-day growth decreased within 1 day of dosing at all sites during nutrients + pesticides treatment. Constructed wetlands were shown to be an effective agricultural best-management tool for trapping pollutants and mitigating ecological impacts of run-off in agricultural watersheds.

  18. Modelling nitrogen removal in a coupled HRP and unplanted horizontal flow subsurface gravel bed constructed wetland (United States)

    Mayo, A. W.; Mutamba, J.

    A coupled model was developed that incorporates all the major nitrogen transformation mechanisms influencing nitrogen removal in aquatic systems. The model simulates nitrogen transformation and removal processes in the high rate pond (HRP) and the subsurface constructed wetland unit (SSCW). The model considered organic nitrogen (ON), ammonia nitrogen (NH 3-N), and nitrate nitrogen ( NO3--N) as the major forms of nitrogen involved in the transformation chains. The influencing transformation mechanisms considered in the model include uptake of inorganic nitrogen by algae and bacteria, mineralization, sedimentation, volatilisation of ammonia and nitrification coupled with denitrification processes. The results showed that improved nitrogen removal occurred with increase in hydraulic time of the HRP unit. It was also revealed that the HRP can effectively be used to promote nitrification and subsurface flow gravel bed constructed wetland can be used as a denitrifying unit. The most efficient mechanisms were determined using a transformation model. The model indicated that nitrification and mineralization were dominant contributing 51.1% and 14.9%, respectively. Denitrification and mineralization were most significant in the SSCW accounting for 43.5% and 16.7%, respectively. Nitrification-denitrification route was observed to be the most significant mechanism for nitrogen removal in the coupled system with an overall contribution of 53%. The model predicted the overall nitrogen removal as 37% compared to 38.4% obtained from field measurements.

  19. Treatment of Oil Wastewater and Electricity Generation by Integrating Constructed Wetland with Microbial Fuel Cell. (United States)

    Yang, Qiao; Wu, Zhenxing; Liu, Lifen; Zhang, Fengxiang; Liang, Shengna


    Conventional oil sewage treatment methods can achieve satisfactory removal efficiency, but energy consumption problems during the process of oil sewage treatment are worth attention. The integration of a constructed wetland reactor and a microbial fuel cell reactor (CW-MFC) to treat oil-contaminated wastewater, compared with a microbial fuel cell reactor (MFC) alone and a constructed wetland reactor (CW) alone, was explored in this research. Performances of the three reactors including chemical oxygen demand (COD), oil removal, and output voltage generation were continuously monitored. The COD removals of three reactors were between 73% and 75%, and oil removals were over 95.7%. Compared with MFC, the CW-MFC with a MnO₂ modified cathode produced higher power density and output voltage. Maximum power densities of CW-MFC and MFC were 3868 mW/m³ (102 mW/m²) and 3044 mW/m³ (80 mW/m²), respectively. The plants in CW-MFC play a positive role for reactor cathode potential. Both plants and cathode modification can improve reactor performance of electricity generation.

  20. Treatment of domestic wastewater by vertical flow constructed wetland planted with umbrella sedge and Vetiver grass. (United States)

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


    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.

  1. Treating surface water with low nutrients concentration by mixed substrates constructed wetlands. (United States)

    Li, Chun J; Wan, Ming H; Dong, Yang; Men, Zhen Y; Lin, Yan; Wu, De Y; Kong, Hai N


    Constructed wetland (CW) has been widely applied in nutrients reduction for eutrophication control, especially in the advanced treatment of effluent of municipal sewage plants or the in-lake river treatment with high hydraulic loads and low nutrient concentrations. But in real application, it shows lower nutrient removal efficiency. The main reason is that traditional substrates, such as soil and gravel have low capacity for nitrogen and phosphorus removal. This study aims to enhance nutrients removal in constructed wetland systems by using series of substrates including calcium silicate hydrate (CSH), vermiculite and ceramsite which are all investigated individually in static experiment or mixed in batch and continuous flow experiments. The result showed that the efficiency of phosphorus removal by CSH could reach 97%, much higher than the other substrates. However, when it was applied in CW, the removal efficiency decreased. Although vermiculite showed the highest ammonia nitrogen removal efficiency of 65.91%, the ammonia nitrogen removal efficiency may have depended on the action of microorganism. High total nitrogen removal efficiency was obtained in continuous-flow mixed substrate CW. Under a hydraulic retention time (HRT) of 18h and hydraulic loading rate (HLR) of 0.496 m(3)/m(3).d, average total nitrogen removal efficiency of above 91% was achieved, but the average phosphorus removal efficiency was around 65% and this needs to be improved further.

  2. Hydrodynamic modelling of free water-surface constructed storm water wetlands using a finite volume technique. (United States)

    Zounemat-Kermani, Mohammad; Scholz, Miklas; Tondar, Mohammad-Mahdi


    One of the key factors in designing free water-surface constructed wetlands (FWS CW) is the hydraulic efficiency (λ), which depends primarily on the retention time of the polluted storm water. Increasing the hydraulic retention time (HRT) at various flow levels will increase λ of the overall constructed wetland (CW). The effects of characteristic geometric features that increase HRT were explored through the use of a two-dimensional depth-average hydrodynamic model. This numerical model was developed to solve the equations of continuity and motions on an unstructured triangular mesh using the Galerkin finite volume formulation and equations of the k-ε turbulence model. Eighty-nine diverse forms of artificial FWS CW with 11 different aspect ratios were numerically simulated and subsequently analysed for four scenarios: rectangular CW, modified rectangular CW with rounded edges, different inlet/outlet configurations of CW, and surface and submerged obstructions in front of the inlet part of the CW. Results from the simulations showed that increasing the aspect ratio has a direct influence on the enhancement of λ in all cases. However, the aspect ratio should be at least 9 in order to achieve an appropriate rate for λ in rectangular CW. Modified rounded rectangular CW improved λ by up to 23%, which allowed for the selection of a reduced aspect ratio. Simulation results showed that CW with low aspect ratios benefited from obstructions and optimized inlet/outlet configurations in terms of improved HRT.

  3. Potential use of mangroves as constructed wetland for municipal sewage treatment in Futian, Shenzhen, China. (United States)

    Yang, Q; Tam, N F Y; Wong, Y S; Luan, T G; Su, W S; Lan, C Y; Shin, P K S; Cheung, S G


    A pilot-scale mangrove wetland was constructed in Futian, Shenzhen for municipal sewage treatment. Three identical belts (length: 33m, width: 3m, depth: 0.5m) were filled with stone (bottom), gravel and mangrove sand (surface). Seedlings of two native mangrove species (Kandelia candel, Aegiceras corniculatum) and one exotic species (Sonneratia caseolaris) were transplanted to the belts with one species for each belt. The hydraulic loading was 5m(3)d(-1) and hydraulic retention time 3d. High levels of removal of COD, BOD(5), TN, TP and NH(3)-N were obtained. The treatment efficiency of S. caseolaris and A. corniculatum was higher than that of K. candel. Faster plant growth was obtained for S. caseolaris. The substrate in the S. caseolaris belt also showed higher enzyme activities including dehydrogenase, cellulase, phosphatase, urease and beta-glucosidase. The removal rates of organic matter and nutrients were positively correlated with plant growth. The results indicated that mangroves could be used in a constructed wetland for municipal sewage treatment, providing post-treatment to remove coliforms was also included.

  4. Intensified nitrate and phosphorus removal in an electrolysis -integrated horizontal subsurface-flow constructed wetland. (United States)

    Gao, Y; Xie, Y W; Zhang, Q; Wang, A L; Yu, Y X; Yang, L Y


    A novel electrolysis-integrated horizontal subsurface-flow constructed wetland system (E-HFCWs) was developed for intensified removal of nitrogen and phosphorus contaminated water. The dynamics of nitrogen and phosphorus removal and that of main water qualities of inflow and outflow were also evaluated. The hydraulic retention time (HRT) greatly enhanced nitrate removal when the electrolysis current intensity was stabilized at 0.07 mA/cm2. When the HRT ranged from 2 h to 12 h, the removal rate of nitrate increased from 20% to 84%. Phosphorus (P) removal was also greatly enhanced-exceeding 90% when the HRT was longer than 4 h in the electrolysis-integrated HFCWs. This improved P removal is due to the in-situ formation of ferric ions by anodizing of sacrificial iron anodes, causing chemical precipitation, physical adsorption and flocculation of phosphorus. Thus, electrolysis plays an important role in nitrate and phosphorus removal. The diversity and communities of bacteria in the biofilm of substrate was established by the analysis of 16S rDNA gene sequences, and the biofilm was abundant with Comamonadaceae and Xanthomonadaceae bacteria in E-HFCWs. Test results illustrated that the electrolysis integrated with horizontal subsurface-flow constructed wetland is a feasible and effective technology for intensified nitrogen and phosphorus removal. Copyright © 2016. Published by Elsevier Ltd.

  5. Intensified nitrogen removal in immobilized nitrifier enhanced constructed wetlands with external carbon addition. (United States)

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


    Nitrogen removal performance response of twelve constructed wetlands (CWs) to immobilized nitrifier pellets and different influent COD/N ratios (chemical oxygen demand: total nitrogen in influent) were investigated via 7-month experiments. Nitrifier was immobilized on a carrier pellet containing 10% polyvinyl alcohol (PVA), 2.0% sodium alginate (SA) and 2.0% calcium chloride (CaCl2). A batch experiment demonstrated that 73% COD and 85% ammonia nitrogen (NH4-N) were degraded using the pellets with immobilized nitrifier cells. In addition, different carbon source supplement strategies were applied to remove the nitrate (NO3-N) transformed from NH4-N. An increase in COD/N ratio led to increasing reduction in NO3-N. Efficient nitrification and denitrification promoted total nitrogen (TN) removal in immobilized nitrifier biofortified constructed wetlands (INB-CWs). The results suggested that immobilized nitrifier pellets combined with high influent COD/N ratios could effectively improve the nitrogen removal performance in CWs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Endophytic bacteria enhance remediation of tannery effluent in constructed wetlands vegetated with Leptochloa fusca. (United States)

    Ashraf, Sobia; Afzal, Muhammad; Naveed, Muhammad; Shahid, Muhammad; Zahir, Zahir Ahmad


    The use of constructed wetlands (CWs) is a promising approach for the remediation of wastewater. The present study aims to develop a plant-bacterial system within CWs for efficient remediation of tannery effluent. In a vertical flow CW vegetated with Leptochloa fusca (Kallar grass), a consortium of three different endophytic bacteria, Pantoea stewartii ASI11, Microbacterium arborescens HU33, and Enterobacter sp. HU38, was used for bioaugmentation. Constructed wetlands vegetated with only L. fusca had the potential to remediate tannery effluent, but augmentation with endophytic bacteria enhanced the growth of L. fusca while aiding in the removal of both organic and inorganic pollutants from the tannery effluent. Moreover, bacterial augmentation decreased toxicity in the effluent as well. Higher number of chromium (Cr)-resistant bacteria was isolated from the rhizosphere and endosphere of L. fusca inoculated with the endophytes than from uninoculated plants. Due to promising bioremediation and detoxification potential of L. fusca, it is reported for the first time as a potential candidate to develop effective CWs for the remediation of polluted effluents in combination with pollutant-degrading endophytic bacteria.

  7. Biological Cr(VI) removal using bio-filters and constructed wetlands. (United States)

    Michailides, Michail K; Sultana, Mar-Yam; Tekerlekopoulou, Athanasia G; Akratos, Christos S; Vayenas, Dimitrios V


    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.

  8. Comparing the efficiency of Cyperus alternifolius and Phragmites australis in municipal wastewater treatment by subsurface constructed wetland. (United States)

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


    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.

  9. Dynamics of nitrogen transformation depending on different operational strategies in laboratory-scale tidal flow constructed wetlands. (United States)

    Chang, Yongjiang; Wu, Shubiao; Zhang, Tao; Mazur, Robert; Pang, Changle; Dong, Renjie


    The influence of different flooded/drained (F/D) time ratios and different effluent flow rates on the dynamics of nitrogen transformations in three laboratory-scale tidal flow constructed wetland systems (TFCWs-A, B, and C) under varying NH4(+)-N and COD influent loadings was investigated in this study. Good organic matter removal performance up to 90% was achieved for all experimental TFCWs under inflow concentrations of 300 and 150 mg/L regardless of F/D and effluent flow rate. The ammonium removal efficiency of wetland with F/D=3h:3h (55%) was higher than that of the wetland with F/D=5h:1h (47%) under an ammonium inflow concentration of 60 mg/L, indicating the positive effect of longer drained and shorter flooded time on tidal-operated wetlands under nitrification. In addition, more uniform oxygen distribution and better nitrification capacity within the wetland might be achieved with a relatively slow effluent flow rate of 0.025 L/s. TFCWs were shown to be a robust and reliable option to achieve high TN removal of 70% due to its repeated cycle of "wet" and "dry" periods, particularly for the treatment of wastewater with high organic content. Moreover, F/D and effluent flow rates of tidal flow constructed wetlands exhibited no significant effect on phosphorus removal in this study. Other techniques, such as pretreatment or post treatment, require further investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Constructed wetlands for wastewater and activated sludge treatment in north Greece: a review. (United States)

    Tsihrintzis, V A; Gikas, G D


    Constructed wetlands used for the treatment of urban, industrial and agricultural wastewater have become very popular treatment systems all over the world. In Greece, these systems are not very common, although the climate is favourable for their use. During recent years, there have been several attempts for the implementation of these systems in Greece, which include, among others, pilot-scale systems used for research, and full-scale systems designed and/or constructed to serve settlements or families. The purpose of this paper is the presentation of systems operating in Northern Greece, which have been studied by the Laboratory of Ecological Engineering and Technology of Democritus University of Thrace and others. A comparison is made of different system types, and the effect of various design and operational parameters is presented. Current research shows the good and continuous performance of these systems.

  11. Influence of substrate heterogeneity on the hydraulic residence time and removal efficiency of horizontal subsurface flow constructed wetlands (United States)

    Carranza-Diaz, O.; Brovelli, A.; Rossi, L.; Barry, D. A.


    Horizontal, subsurface flow constructed wetlands are wastewater treatment devices. The influent polluted water flows through a porous substrate where the contaminants are removed, for example by microbial oxidation, surface adsorption and mineral precipitation. These systems are widely used with varying degrees of success to treat municipal and agricultural contaminated waters and remove the organic carbon and nutrient load. Constructed wetlands are an appealing and promising technology, because they (i) are potentially very efficient in removing the pollutants, (ii) require only a small external energy input and (iii) require low maintenance. However, practical experience has shown that the observed purification rate is highly variable and is often much smaller than expected. One of the numerous reasons proposed to explain the variable efficiency of constructed wetlands is the existence of highly conductive zones within the porous substrate, which produce a dramatic reduction of the hydraulic residence time and therefore directly decreases the overall water purification rate. This work aims to understand quantitatively the relationship between the spatial variability in the hydraulic properties of the substrate and the effective residence time in constructed wetlands. We conducted two suites of stochastic numerical simulations, modelling the transport of a conservative tracer in a three-dimensional simulated constructed wetland in one case, and the microbial oxidation of a carbon source in the other. Within each group of simulations, different hydraulic conductivity fields were tested. These were based on a log-normal, spatially correlated random field (with exponential spatial correlation). The amount of heterogeneity was varied by changing the variance correlation length in the three directions. For each set of parameters, different realizations are considered to deduce both the expected residence time for a certain amount of heterogeneity, and its range of

  12. Comparative assessment of managed aquifer recharge versus constructed wetlands in managing chemical and microbial risks during wastewater reuse: A review

    KAUST Repository

    Hamadeh, Ahmed F.


    Constructed wetlands (CWs) and managed aquifer recharge (MAR) represent commonly used natural treatment systems for reclamation and reuse of wastewater. However, each of these technologies have some limitations with respect to removal of different contaminants. Combining these two technologies into a hybrid CW-MAR system will lead to synergy in terms of both water quality and costs. This promising technology will help in the reduction of bacteria and viruses, trace and heavy metals, organic micropollutants, and nutrients. Use of subsurface flow CWs as pre-treatment for MAR has multiple benefits: (i) it creates a barrier for different microbial and chemical pollutants, (ii) it reduces the residence time for water recovery, and (iii) it avoids clogging during MAR as CWs can remove suspended solids and enhance the reclaimed water quality. This paper analyzes the removal of different contaminants by CW and MAR systems based on a literature review. It is expected that a combination of these natural treatment systems (CWs and MAR) could become an attractive, efficient and cost-effective technology for water reclamation and reuse. © IWA Publishing 2014.

  13. Emergent macrophytes select for nitrifying and denitrifying microorganisms in constructed wetlands (United States)

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


    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

  14. Macroinvertebrate assemblages and biodiversity levels: ecological role of constructed wetlands and artificial ponds in a natural park

    Directory of Open Access Journals (Sweden)

    Laura Sartori


    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Constructed wetlands play an important role in water supply, floodwater retention and nutrient removal, at the same time allowing the restoration of lost habitat and the preservation of biodiversity. There is little knowledge about the biodiversity that can be found in these artificial environments along time, especially at the invertebrate community level. Macroinvertebrate assemblages, water chemistry, morphology, and environmental characteristics of natural ponds, artificial pools and constructed wetlands in Parco Pineta (Northern Italy were studied to evaluate the effects of local factors on macroinvertebrate communities. The objective was to verify if each ecosystem could equally contribute to local biodiversity, regardless of its natural or artificial origin. Principal Components Analysis showed that ponds were divided into clusters, based on their morphology and their water quality, independently from their origin. The composition of macroinvertebrate communities was similar among natural wetlands and ponds artificially created to provide new habitats in the park, while it was different among natural wetlands and constructed wetlands created for wastewater treatment purposes. Biodiversity of natural ponds and constructed wetlands, evaluated using taxa richness, Shannon index, and Pielou index, was comparable. Canonical Correspondence Analysis highlighted differences in macroinvertebrate community composition and pointed out the relationships among macroinvertebrates and various environmental variables: habitat heterogeneity resulted as the most relevant factor that influences taxa richness. Water quality also affects the macroinvertebrate community structure. We determined that constructed wetlands with higher pollutant concentrations show different assemblage compositions but comparable overall macroinvertebrate biodiversity. Constructed wetlands became valuable ecological elements

  15. On the fit of statistical and k-C* models to projecting treatment performance in a constructed wetland system


    Babatunde, A.O.; Zhao, Y.Q.; Doyle, R J; Rackard, S.M.; Kumar, J.L.G.; Hu, Y.S.


    The objective of this study was to assess the suitability of statistical and the k-C* models to projecting treatment performance of constructed wetlands by applying the models to predict the final effluent concentrations of a pilot field-scale constructed wetlands system (CWs) treating animal farm wastewater. The CWs achieved removal rates (in g/m2.d) ranging from 7.1-149.8 for BOD5, 49.8-253.8 for COD and 7.1-47.0 for NH4-N. Generally, it was found that the statistical models developed from ...

  16. Evaluation of an alternative method for wastewater treatment containing pesticides using solar photocatalytic oxidation and constructed wetlands. (United States)

    Berberidou, Chrysanthi; Kitsiou, Vasiliki; Lambropoulou, Dimitra A; Antoniadis, Αpostolos; Ntonou, Eleftheria; Zalidis, George C; Poulios, Ioannis


    The present study proposes an integrated system based on the synergetic action of solar photocatalytic oxidation with surface flow constructed wetlands for the purification of wastewater contaminated with pesticides. Experiments were conducted at pilot scale using simulated wastewater containing the herbicide clopyralid. Three photocatalytic methods under solar light were investigated: the photo-Fenton and the ferrioxalate reagent as well as the combination of photo-Fenton with TiO 2 P25, which all led to similar mineralization rates. The subsequent treatment in constructed wetlands resulted in further decrease of DOC and inorganic ions concentrations, especially of NO 3 - . Clopyralid was absent in the outlet of the wetlands, while the concentration of the detected intermediates was remarkably low. These findings are in good agreement with the results of phytotoxicity of the wastewater, after treatment with the ferrioxalate/wetlands process, which was significantly reduced. Thus, this integrated system based on solar photocatalysis and constructed wetlands has the potential to effectively detoxify wastewater containing pesticides, producing a purified effluent which could be exploited for reuse applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Metal and metalloid removal in constructed wetlands, with emphasis on the importance of plants and standardized measurements: A review. (United States)

    Marchand, L; Mench, M; Jacob, D L; Otte, M L


    This review integrates knowledge on the removal of metals and metalloids from contaminated waters in constructed wetlands and offers insight into future R&D priorities. Metal removal processes in wetlands are described. Based on 21 papers, the roles and impacts on efficiency of plants in constructed wetlands are discussed. The effects of plant ecotypes and class (monocots, dicots) and of system size on metal removal are addressed. Metal removal rates in wetlands depend on the type of element (Hg > Mn > Fe = Cd > Pb = Cr > Zn = Cu > Al > Ni > As), their ionic forms, substrate conditions, season, and plant species. Standardized procedures and data are lacking for efficiently comparing properties of plants and substrates. We propose a new index, the relative treatment efficiency index (RTEI), to quantify treatment impacts on metal removal in constructed wetlands. Further research is needed on key components, such as effects of differences in plant ecotypes and microbial communities, in order to enhance metal removal efficiency. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Studies on sustainability of simulated constructed wetland system for treatment of urban waste: Design and operation. (United States)

    Upadhyay, A K; Bankoti, N S; Rai, U N


    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Comparisons of mosquito populations before and after construction of a wetland for water quality improvement in Pitt County, North Carolina, and data-reliant vectorborne disease management. (United States)

    Anderson, Alice L; O'Brien, Kevin; Hartwell, Megan


    Wetlands serve an important purpose in flood control and water quality, but constructed-wetland sites also provide habitats for mosquito breeding. Communities near constructed-wetland sites often raise a "mosquito" objection when constructed wetlands are proposed. Wildlife and wetland advocates can confuse the public by making unsubstantiated claims about natural predators eliminating or controlling mosquito problems in a constructed wetland. Management of constructed-wetland mosquito habitat, with adequate mosquito surveillance and data analysis, can help lead to a successful project and satisfied citizens. The cooperative project described in this paper, was conducted in the town of Simpson, North Carolina, and was designed to determine the mosquito population impact of wetland construction at Mill Branch Stream, a small tributary of the Tar River in Eastern North Carolina. In the authors' analysis of three years of mosquito surveillance data, month (time of year standing in for temperature and day length) was a significant factor in regression analysis for mosquito numbers, but rainfall was not. Numbers of mosquitoes were not found to be significantly higher after construction than before construction.

  20. 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 (United States)

    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 '...

  1. Embedding constructed wetland in sequencing batch reactor for enhancing nutrients removal: A comparative evaluation. (United States)

    Liu, Ranbin; Zhao, Yaqian; Zhao, Jinhui; Xu, Lei; Sibille, Caroline


    In the present study, a novel green bio-sorption reactor (GBR) was firstly proposed and preliminarily investigated by embedding constructed wetland (CW) into the aeration tank of the conventional activated sludge (CAS). This integrated novel system owns the striking features of adding carriers of wetland substrate (i.e. the dewatered alum sludge in this case) in CAS for robust phosphorus adsorption and enriching the biomass. Meanwhile, the "green" feature of this GBR imparted aesthetic value of CW to the CAS system. The preliminary 3-month trial of GBR based on a sequencing batch reactor (GB-SBR) with diluted piggery wastewater demonstrated an average removal of 96%, 99% and 90% for BOD, TP and TN, respectively. The comparison with moving bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) reflected the advantages of GBR over purification performance, aesthetic value and potential carbon sink. Moreover, the carriers used in the GBR are dewatered alum sludge which is in line with the policy of "recycle, reuse and reduce". Overall, this GBR undoubtedly offered a more sustainable and economical solution for retrofitting the aging CAS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Microbiological investigations for sanitary assessment of wastewater treated in constructed wetlands. (United States)

    Ulrich, Hagendorf; Klaus, Diehl; Irmgard, Feuerpfeil; Annette, Hummel; Juan, Lopez-Pila; Regine, Szewzyk


    Microbiological investigations into the occurrence and fate of pathogens in wastewater were carried out in a multi-annual measurement programme, using samples from three artificial wetlands equipped with pre-treatment systems (multi-chamber septic tanks, lagoons) and predominantly treating domestic wastewater. In this study, the concentrations of indicator organisms and pathogenic or potentially pathogenic microorganisms were determined in the various components or stages of the systems. The evaluation of data from some 3.600 microbiological analyses and a comparison with older data from a plant which has already been operation for 18 y made it possible for the first time ever to include operational factors in the assessment. Average removal of all major indicator organisms and pathogens is 1.5-2.5 log units for one-stage systems and increases to 3-5 log units for multi-stage systems. Significant differences between horizontal and vertical filters were not found. If no clogging problems arise during their operation, multi-stage systems can meet the requirements of the EU bathing water and irrigation water directives. Influent concentration, wastewater temperature, and hydraulic loading rate were found to be major factors of influence. The performance of constructed wetlands in removing microorganisms is clearly superior to that of conventional biological activated sludge systems.

  3. Nitrous oxide emission from polyculture constructed wetlands: Effect of plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanhua [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China); Inamori, Ryuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kong Hainan [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China)], E-mail:; Xu Kaiqin [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan Unviversity, Wuhan 430072 (China); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kondo, Takashi [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); Zhang Jixiang [School of Economics and Management, Southeast University, Nanjing, Jiangsu 210096 (China)


    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N{sub 2}O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N{sub 2}O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N{sub 2}O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N{sub 2}O m{sup -2} d{sup -1}. The highest N{sub 2}O 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 N{sub 2}O 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 N{sub 2}O formation. - Zizania latifolia has a large contribution to global warming.

  4. Constructed Wetlands for Combined Sewer Overflow Treatment—Comparison of German, French and Italian Approaches

    Directory of Open Access Journals (Sweden)

    Daniel Meyer


    Full Text Available Combined sewer systems are designed to transport stormwater surface run off in addition to the dry weather flows up to defined limits. In most European countries, hydraulic loads greater than the design flow are discharged directly into receiving water bodies, with minimal treatment (screening, sedimentation, or with no treatment at all. One feasible solution to prevent receiving waters from strong negative impacts seems to be the application of vertical flow constructed wetlands. In Germany, first attempts to use this ecological technology were recognized in early 1990s. Since then, further development continued until a high level of treatment performance was reached. During recent years the national “state-of-the-art” (defined in 2005 was adapted in other European countries, including France and Italy. Against the background of differing national requirements in combined sewer system design, substantial developmental steps were taken. The use of coarser filter media in combination with alternating loadings of separated filter beds allows direct feedings with untreated combined runoff. Permanent water storage in deep layers of the wetland improves the system’s robustness against extended dry periods, but contains operational risks. Besides similar functions (but different designs and layouts, correct dimensioning of all approaches suffers from uncertainties in long-term rainfall predictions as well as inside sewer system simulation tools.

  5. Nutrient removal in tropical subsurface flow constructed wetlands under batch and continuous flow conditions. (United States)

    Zhang, Dong Qing; Tan, Soon Keat; Gersberg, Richard M; Zhu, Junfei; Sadreddini, Sara; Li, Yifei


    The aim of this investigation was to evaluate the influence of batch versus continuous flow on the removal efficiencies of chemical oxygen demand (COD), nitrogen (N) and total phosphorus (TP) in tropical subsurface flow constructed wetlands (SSF CW). The quantitative role of the higher aquatic plants in nutrient removal in these two operational modes was also investigated. Results indicated no significant difference (p > 0.05) in COD removal between batch and continuous flow modes for either the planted or unplanted treatments. Furthermore, the batch-loaded planted wetlands showed significantly (p hydraulic retention time (HRT), the presence of plants significantly enhanced both ammonia oxidation and TP removal in both batch and continuous modes of operation as compared to that for unplanted beds. An estimation of the quantitative role of aeration from drain and fill operation at a 4-day HRT, as compared to rhizosphere aeration by the higher aquatic plant, indicated that drain and fill operation might account for only less than half of the higher aquatic plant's quantitative contribution of oxygen (1.55 g O2 per m2 per day for batch flow versus 1.13 g O2 per m2 per day for continuous flow). Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Bioaugmentation in a pilot-scale constructed wetland to treat domestic wastewater in summer and autumn. (United States)

    Pei, Haiyan; Shao, Yuanyuan; Chanway, Christopher Peter; Hu, Wenrong; Meng, Panpan; Li, Zheng; Chen, Yang; Ma, Guangxiang


    In order to determine whether bioaugmentation is an effective technique in wetlands before the plants were harvested, the nitrogen (N) removal from a constructed wetland (CW) planted with Phragmites was evaluated after inoculating with Paenibacillus sp. XP1 in Northern China. The experiment was loaded with secondary effluent of rural domestic wastewater (RDW) using the batch-loaded method for over a 17-day period in summer and autumn. Chemical oxygen demand (CODcr), ammonia nitrogen (NH3-N), and total nitrogen (TN) decreased significantly in the CW with Phragmites inoculated with Paenibacillus sp. XP1. Four days after treatments were set up, the removal efficiencies were found to be 76.2 % for CODcr, 83 % for NH3-N, and 63.8 % for TN in summer and 69.5 % for CODcr, 76.9 % for NH3-N, and 55.6 % for TN in autumn, which were higher than the control group without inoculation during the entire 17-day experiment. The inoculated bacteria did not have a noticeable effect on total phosphorus (TP) removal in autumn. However, bioaugmentation still keep a low P concentration in the whole CW. First-order kinetic model represented well the CODcr, TN, and TP decay in CWs with bioaugmentation, resulting in very good coefficients of determination, which ranged from 0.97 to 0.99. It indicated that bioaugmentation would be an effective treatment for pollutant removal from RDW in the CWs.

  7. Evaluation of Ageratum conyzoides in field scale constructed wetlands (CWs) for domestic wastewater treatment. (United States)

    Tilak, A S; Wani, Suhas P; Datta, A; Patil, M D; Kaushal, M; Reddy, K R


    Ageratum conyzoides were evaluated in field scale subsurface flow constructed wetlands (CWs) to quantify its nitrogen (N) and phosphorus (P) uptake and compare with wetland plants (Pistia stratiotes, Typha latifolia and Canna indica). The two-field scale subsurface flow CWs, located in the International Crops Research Institute for Semi-Arid Tropics, received wastewater from an urban colony. The CW1 and CW2 had the same dimensions (length:10 m, width:3 m, total depth:1.5 m and sand and gravel:1 m), similar flow rates (3 m3/d), hydraulic loading rates (HLRs-10 cm/d) and hydraulic retention time (HRT-5 days) from July 2014-August 2015. The vegetation in both CWs consisted of Pistia stratiotes, Typha latifolia, Canna indica, and Ageratum conyzoides, respectively. The CW1 (% reduction with respect to concentrations) reduced total suspended solids (TSS) (68%), NH4-N (26%), NO3-N (30%), soluble reactive P (SRP) (20%), chemical oxygen demand (COD) (45%) and fecal coliforms (71%), while the CW2 (%-reduction with respect to concentrations) reduced TSS (63%), NH4-N (32%), NO3-N (26%), SRP (35%), COD (39%) and fecal coliforms (70%). Ageratum conyzoides can be used in combination with Pistia stratiotes, Typha latifolia and Canna indica to enhance removal of excessive N, P and fecal coliforms from domestic wastewater.

  8. Adaptive neuro-fuzzy inference system for real-time monitoring of integrated-constructed wetlands. (United States)

    Dzakpasu, Mawuli; Scholz, Miklas; McCarthy, Valerie; Jordan, Siobhán; Sani, Abdulkadir


    Monitoring large-scale treatment wetlands is costly and time-consuming, but required by regulators. Some analytical results are available only after 5 days or even longer. Thus, adaptive neuro-fuzzy inference system (ANFIS) models were developed to predict the effluent concentrations of 5-day biochemical oxygen demand (BOD5) and NH4-N from a full-scale integrated constructed wetland (ICW) treating domestic wastewater. The ANFIS models were developed and validated with a 4-year data set from the ICW system. Cost-effective, quicker and easier to measure variables were selected as the possible predictors based on their goodness of correlation with the outputs. A self-organizing neural network was applied to extract the most relevant input variables from all the possible input variables. Fuzzy subtractive clustering was used to identify the architecture of the ANFIS models and to optimize fuzzy rules, overall, improving the network performance. According to the findings, ANFIS could predict the effluent quality variation quite strongly. Effluent BOD5 and NH4-N concentrations were predicted relatively accurately by other effluent water quality parameters, which can be measured within a few hours. The simulated effluent BOD5 and NH4-N concentrations well fitted the measured concentrations, which was also supported by relatively low mean squared error. Thus, ANFIS can be useful for real-time monitoring and control of ICW systems.

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

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


    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Observations of nitrogen and phosphorus biogeochemistry in a surface flow constructed wetland. (United States)

    Erler, Dirk V; Tait, Douglas; Eyre, Bradley D; Bingham, Michael


    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. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. The potential for constructed wetlands to treat alkaline bauxite-residue leachate: Phragmites australis growth. (United States)

    Higgins, D; Curtin, T; Pawlett, M; Courtney, R


    High alkalinity (pH > 12) of bauxite-residue leachates presents challenges for the long-term storage and managements of the residue. Recent evidence has highlighted the potential for constructed wetlands to effectively buffer the alkalinity, but there is limited evidence on the potential for wetland plants to establish and grow in soils inundated with residue leachate. A pot-based trial was conducted to investigate the potential for Phragmites australis to establish and grow in substrate treated with residue leachate over a pH range of 8.6-11.1. The trial ran for 3 months, after which plant growth and biomass were determined. Concentrations of soluble and exchangeable trace elements in the soil substrate and also in the aboveground and belowground biomass were determined. Residue leachate pH did not affect plant biomass or microbial biomass. With the exception of Na, there was no effect on exchangeable trace elements in the substrate; however, increases in soluble metals (As, Cd and Na) were observed with increasing leachate concentration. Furthermore, increases in Al, As and V were observed in belowground biomass and for Cd and Cr in aboveground biomass. Concentrations within the vegetation biomass were less than critical phytotoxic levels. Results demonstrate the ability for P. australis to grow in bauxite-residue leachate-inundated growth media without adverse effects.

  12. Trace metals in Phragmites australis and Phalaris arundinacea growing in constructed and natural wetlands. (United States)

    Vymazal, Jan; Svehla, Jaroslav; Kröpfelová, Lenka; Chrastný, Vladislav


    Constructed wetlands with horizontal subsurface flow (HF CWs) designed for treatment of municipal sewage have been monitored extensively with respect to removal of organics, suspended solids, nitrogen, phosphorus and bacteria. However, the information on the removal of various metals and metalloids in these systems is very limited. During the period 2002-2004 aboveground and belowground biomass of Phragmites australis (common reed) and Phalaris arundinacea (reed canarygrass) were sampled in three HF CWs in the Czech Republic. Concentrations of monitored elements in both aboveground and belowground plant tissues were similar to those found in plants growing in natural stands. The concentrations were much lower as compared to those found in plants growing in wetlands receiving acid mine drainage waters, waters from smelters or highway runoff. Concentrations decrease in the order of roots>rhizomes>leaves>stems. The leaf:stem concentration ratios were quite similar for all monitored elements ranging between 1.0 and 1.9. The root:leaf concentration ratio varied widely between 1.5 (Cu) and 54 (Cr) with a mean value of 20.0. Belowground/aboveground plant tissue concentration ratios varied from 2.2 (Cu) to 32 (Cr) with the average value of 9.9.

  13. Phytoremediation of wastewater with Limnocharis flava, Thalia geniculata and Typha latifolia in constructed wetlands. (United States)

    Anning, Alexander K; Korsah, Percy E; Addo-Fordjour, Patrick


    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.

  14. Energy capture and nutrients removal enhancement through a stacked constructed wetland incorporated with microbial fuel cell. (United States)

    Xu, Lei; Zhao, Yaqian; Wang, Tongyue; Liu, Ranbin; Gao, Fei


    To improve the sustainability of constructed wetlands (CWs), a novel tiered wetland system integrated with a microbial fuel cell (MFC) was developed in this study. Compared to the single stage CW, chemical oxygen demand (COD) removal efficiency was improved from 83.2% to 88.7%. More significantly, this tiered system significantly enhanced total nitrogen removal efficiency (an increase from 53.1% to 75.4%). In terms of MFC integration, a gradually decreased performance in electricity production was observed during its 3 months of operation (the voltage dropped from nearly 600 mV to less than 300 mV), which resulted in a reduction of power density from around 2 W/m3 to less than 0.5 W/m3. The deterioration in performance of the air-cathode is the main reason behind this, since the electrode potential of the cathode under open circuit reduced from 348.5 mV to 49.5 mV while the anode potential kept constant at around -400 mV. However, in spite of its electrical performance reduction, it was proved that MFC integration enhanced COD removal and the nitrification process. Further work is needed to improve the stability and feasibility of this new system.

  15. Urban wastewater process by aerobic constructed wetland; Depuracion de aguas residuales urbanas utilizando un humedal artificial aerobio

    Energy Technology Data Exchange (ETDEWEB)

    Gil Rodriguez, M.


    In this paper the experiences of urban wastewater treatment are shown in an aerobic constructed wetland, using phragmites australis.They were carried out changes on the design and operation of aerobic constructed wetlands of subsurface flow, in order to increase denitrification and biodegradation rate and to diminish the surface of the installation. the flow was channeled through a long and narrow channel to get bigger biodegradation rate to approach to the plug flow performance. the active space of process consists of two sites, one first anoxic in which denitrification takes place, and in the other one the wetland in oxygenated environment the organic matters of the wastewater are consumed by biodegradation and it takes place nitrification, and utilization of nitrates and phosphates by the vegetable culture. (Author) 14 refs.

  16. [Treatment of marine-aquaculture effluent by the multi-soil-layer (MSL) system and subsurface flow constructed wetland]. (United States)

    Song, Ying; Huang, Yu-ting; Ge, Chuan; Zhang, Hao; Chen, Xin; Zhang, Zhi-jianz; Luo, An-cheng


    To evaluate the feasibility of using multi-soil-layer (MSL) system and subsurface flow constructed wetland to treat the wastewater of marine cultured Penaeus vannamei and to determine the suitable process for the local aquaculture wastewater pollution characteristics. In this study, MSL system and four constructed wetland systems with Spartina anglica, Phragmites australis, Typha latifolia and unplanted system were evaluated for their potentials of pollutants removal capacity. The results showed the average removal rates of chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH(4)+ -N) and nitrate (NO-(3) -N) by MSL system were 80. 38% ± 2. 14% , 68. 14% ± 3.51% , 40.79% ± 3. 10% , 42. 68% ± 2.90% and 54. 19% ± 5. 15% , respectively. Additionally, the ability of pollutants removal of other four wetland systems decreased in the order: Spartina anglica, Phragmites australis, Typha latifolia and unplanted system.

  17. Sulphur transformation and deposition in the rhizosphere of Juncus effusus in a laboratory-scale constructed wetland. (United States)

    Wiessner, A; Kuschk, P; Jechorek, M; Seidel, H; Kästner, M


    Sulphur cycling and its correlation to removal processes under dynamic redox conditions in the rhizosphere of helophytes in treatment wetlands are poorly understood. Therefore, long-term experiments were performed in laboratory-scale constructed wetlands treating artificial domestic wastewater in order to investigate the dynamics of sulphur compounds, the responses of plants and nitrifying microorganisms under carbon surplus conditions, and the generation of methane. For carbon surplus conditions (carbon:sulphate of 2.8:1) sulphate reduction happened but was repressed, in contrast to unplanted filters mentioned in literature. Doubling the carbon load caused stable and efficient sulphate reduction, rising of pH, increasing enrichment of S(2-) and S(0) in pore water, and finally plant death and inhibition of nitrification by sulphide toxicity. The data show a clear correlation of the occurrence of reduced S-species with decreasing C and N removal performance and plant viability in the experimental constructed wetlands.

  18. Evaluation of hydraulic characteristics in a pilot-scale constructed wetland using a multi-tracer experiment (United States)

    Birkigt, Jan; Stumpp, Christine; Małoszewski, Piotr; Richnow, Hans H.; Nijenhuis, Ivonne


    In recent years, constructed wetland systems have become into focus as means for organic contaminant removal. The use of constructed wetlands as part of water treatment offers great opportunities to realize significant savings in future wastewater treatment costs for small communities and the adaptation of large wastewater treatment plants. Wetland systems provide a highly reactive environment in which several elimination pathways of organic chemicals may be present at the same time; however, these elimination processes and hydraulic conditions are usually poorly understood. Previously, in our study site monochlorobenzene removal was observed in a pilot-scale wetland system which treats contaminated groundwater from the regional aquifer in Bitterfeld. The degradation was linked to either aerobic or anaerobic, iron- or sulfate- reduction or multiple processes, in parallel. However, it was unclear how the groundwater flows through this system, precluding a more founded understanding of the flow and transport processes. Therefore, we investigated the flow system in this three dimensional pilot-scale constructed wetland applying a multi tracer test combined with a mathematical model to evaluate the hydraulic characteristics. The pilot system consisted of a 6 m length x 1 m wide x 0.5 m depth gravel filter with a triple inflow distributed evenly approx. 5 cm from the bottom at the inflow. Three conservative tracers (uranine, bromide and deuterium) were injected as a pulse at the inflow and analyzed at 4 meters distance from the inflow at three different depths to obtain residence time distributions of groundwater flow in the gravel bed of the wetland. A mathematical multi-flow dispersion model was used to model the tracer breakthrough curves of the different sampling levels, which assumes parallel combinations of the one-dimensional advection-dispersion equation. The model was successfully applied to fit the experimental tracer breakthrough curves by assuming three flow

  19. In situ denitrification and DNRA rates in groundwater beneath an integrated constructed wetland. (United States)

    Jahangir, M M R; Fenton, O; Müller, C; Harrington, R; Johnston, P; Richards, K G


    Evaluation of the environmental benefits of constructed wetlands (CWs) requires an understanding of their impacts on the groundwater quality under the wetlands. Empirical mass-balance (nitrogen in/nitrogen out) approaches for estimating nitrogen (N) removal in CWs do not characterise the final fate of N; where nitrate (NO3--N) could be reduced to either ammonium (NH4+-N) or N2 with the potential for significant production of N2O. Herein, in situ denitrification and DNRA (dissimilatory nitrate reduction to ammonium) rates were measured in groundwater beneath cells of an earthen lined integrated constructed wetland (ICW, used to remove the nutrients from municipal wastewater) using the 15N-enriched NO3--N push-pull method. Experiments were conducted utilising replicated (n = 3) shallow (1 m depth) and deep (4 m depth) piezometers installed along two control planes. These control planes allowed for the assessment of groundwater underlying high (Cell 2, septic tank waste) and low (Cell 3) load cells of the ICW. Background piezometers were also installed off-site. Results showed that denitrification (N2O-N + N2-N) and DNRA were major NO3--N consumption processes accounting together for 54-79% of the total biochemical consumption of the applied NO3--N. Of which 14-16% and 40-63% were consumed by denitrification and DNRA, respectively. Both processes differed significantly across ICW cells indicating that N transformation depends on nutrient loading rates and were significantly higher in shallow compared to the deep groundwater. In such a reduced environment (low dissolved oxygen and low redox potential), higher DNRA over the denitrification rate can be attributed to the high C concentration and high TC/NO3--N ratio. Low pH (6.5-7.1) in this system might have limited denitrification to some extent to an incomplete state, evidenced by a high N2O-N/(N2O-N+N2-N) ratio (0.35 ± 0.17, SE). A relatively higher N2O-N/(N2O-N+N2-N) ratio and higher DNRA rate over

  20. Effects of constructed wetland design on ibuprofen removal – A mesocosm scale study

    DEFF Research Database (Denmark)

    Zhang, Liang; Lyu, Tao; Zhang, Yang


    This study aimed to investigate the effects of constructed wetland design (unsaturated, saturated and aerated saturated) and plant species (Juncus, Typha, Berula, Phragmites and Iris) on the mass removal and removal kinetics of the pharmaceutical ibuprofen. Planted systems had higher ibuprofen...... removal rates (29%–99%) than in the unplanted ones (15%–85%) in all designs. The use of forced aeration improved ibuprofen removal only in the unplanted mesocosms. In general, ibuprofen removal followed an area-based first-order removal kinetics model with removal rate coefficients (kA) varying between 3...... and 35 cm/d. The ibuprofen removal was mainly attributed to microbial degradation by the fixed bed biofilm, but plant uptake and degradation within plant tissues also occurred. The ibuprofen removal was positively correlated with the oxygen concentration in the water and the removal of nutrients...

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

    Directory of Open Access Journals (Sweden)

    Amit Gross


    Full Text Available 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.

  2. Statistical modelling of organic matter and emerging pollutants removal in constructed wetlands. (United States)

    Hijosa-Valsero, María; Sidrach-Cardona, Ricardo; Martín-Villacorta, Javier; Cruz Valsero-Blanco, M; Bayona, Josep M; Bécares, Eloy


    Multiple regression models, clustering tree diagrams, regression trees (CHAID) and redundancy analysis (RDA) were applied to the study of the removal of organic matter and pharmaceuticals and personal care products (PPCPs) from urban wastewater by means of constructed wetlands (CWs). These four statistical analyses pointed out the importance of physico-chemical parameters, plant presence and chemical structure in the elimination of most pollutants. Temperature, pH values, dissolved oxygen concentration, redox potential and conductivity were related to the removal of the studied substances. Plant presence (Typha angustifolia and Phragmites australis) enhanced the removal of organic matter and some PPCPs. Multiple regression equations and CHAID trees provided numerical estimations of pollutant removal efficiencies in CWs. These models were validated and they could be a useful and interesting tool for the quick estimation of removal efficiencies in already working CWs and for the design of new systems which must fulfil certain quality requirements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Furosemide removal in constructed wetlands: Comparative efficiency of LECA and Cork granulates as support matrix. (United States)

    Machado, A I; Dordio, A; Fragoso, R; Leitão, A E; Duarte, E


    The removal efficiency of LECA and cork granulates as support matrix for pharmaceuticals active compounds in a constructed wetland system was investigated using the diuretic drug Furosemide. Kinetics studies were performed testing three different concentrations of Furosemide in an ultrapure water matrix, along seven days. LECA achieved higher removal values compared to cork granulates. However, cork granulates presented a higher removal in the first 24 h of contact time compared to the other adsorbent. The kinetic studies showed that LECA and cork granulates have different adsorption behaviours for Furosemide which is controlled by different adsorption mechanisms. Both materials showed good removal efficiencies and a combination of the two should be further explored in order to applied both materials as support matrix to cope with different furosemide concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Constructed wetlands for municipal solid waste landfill leachate treatment. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Peverly, J.; Sanford, W.E.; Steenhuis, T.S. [Cornell Univ., Ithaca, NY (United States)


    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.

  5. Assessing environmental impacts of constructed wetland effluents for vegetable crop irrigation. (United States)

    Castorina, A; Consoli, S; Barbagallo, S; Branca, F; Farag, A; Licciardello, F; Cirelli, G L


    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.

  6. Potential of constructed wetlands microcosms for the removal of veterinary pharmaceuticals from livestock wastewater. (United States)

    Carvalho, Pedro N; Araújo, José Luís; Mucha, Ana P; Basto, M Clara P; Almeida, C Marisa R


    The aim of the present work was to evaluate, at microcosm level, the capacity of constructed wetlands (CWs) to remove veterinary pharmaceutical compounds, from wastewater. Results indicated that CWs have potential to mitigate the release of veterinary drugs, namely enrofloxacin (ENR, a fluoroquinolone) and tetracycline (TET, tetracyclines family). Removal efficiencies of 94% and 98% where achieved for TET and ENR, respectively, when treating pigfarm wastewater effluent doped at 100 μg L(-1) drug level, along twelve weeks. Occurrence of adsorption of the drugs to CWs substrate may be the predominant mechanism for ENR, although for TET there are signs that degradation is also occurring. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Accumulation of Metals and Boron in Phragmites australis Planted in Constructed Wetlands Polishing Real Electroplating Wastewater. (United States)

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


    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.

  8. Temperature Impact of Nitrogen Transformation in Technological System: Vertical Flow Constructed Wetland and Polishing Pond

    Directory of Open Access Journals (Sweden)

    Myszograj Sylwia


    Full Text Available The article describes the results of the research, purpose of which was to evaluate influence of the temperature on the effectiveness of nitrification and denitrification in the sewage treatment system consisting of vertical flow constructed wetland and polishing pond. During the analysed period, the efficiency of removing total nitrogen was low and amounted to 12.7%. In the polishing pond in the summer period, content of total nitrogen in treated sewages was further decreased by nearly 50%. In the winter period, the polishing pond fulfilled mainly retention role and thus did not improve effectiveness of the whole system. Temperature coefficients, calculated on the basis of single first-order kinetics, for nitrification process in the filter bed (N-NH4+ and denitrification process in the polishing pond (N-NO3− amounted to 1.039 and 1.089, respectively.

  9. Cold Temperature Effects on Long-Term Nitrogen Transformation Pathway in a Tidal Flow Constructed Wetland. (United States)

    Pang, Yunmeng; Zhang, Yan; Yan, Xingjun; Ji, Guodong


    The present study investigated long-term treatment performance and nitrogen transformation mechanisms in tidal flow constructed wetlands (TFCWs) under 4, 8, and 12 °C temperature regimes. High and stable ammonium (NH4(+)-N) removal efficiency (93-96%) was achieved in our TFCWs, whereas nitrate (NO3(-)-N) was accumulated at different levels under different temperatures. Quantitative response relationships showed anammox/amoA, (narG+napA)/amoA, and (narG+napA)/bacteria were the respective key functional gene groups determining 4, 8, and 12 °C NO3(-)-N reduction. Pathway analysis revealed the contribution of these functional gene groups along a depth gradient. In addition, denitrification process increased, while anammox process decreased consistent with a rise in temperature from 4 to 12 °C. Furthermore, cold temperatures exhibited different effects on anammox and denitrification and their long-term acclimatization capacities changed with temperature.

  10. Soil microbial abundances and enzyme activities in different rhizospheres in an integrated vertical flow constructed wetland

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Ying; Jiang, Yueping; Jiang, Qinsu; Min, Hang; Fan, Haitian; Zeng, Qiang; Chang, Jie [College of Life Sciences, Zhejiang University, Hangzhou (China); Zhang, Chongbang [School of Life Sciences, Taizhou University, Linhai (China); Yue, Chunlei [Zhejiang Forestry Academy, Hangzhou (China)


    Rhizosphere microorganism is an important bio-component for wastewater treatment in constructed wetlands (CWs). Microbial abundance and enzyme activities in the rhizospheres of nine plant species were investigated in an integrated vertical-flow CW. The abundance of denitrifiers, as well as urease, acid, and alkaline phosphatase activities were positively correlated to plant root biomass. The abundance of bacteria, fungi, actinomycetes, ammonifiers, denitrifiers, and phosphorus decomposers, related to nutrient removal efficiencies in CWs, greatly varied among rhizospheres of different plant species (p < 0.05). Significant differences in rhizosphere enzyme activity among plant species were also observed (p < 0.05), with the exception of catalase activity. The principal component analysis using the data of microbial abundance and enzyme activity showed that Miscanthus floridulus, Acorus calamus, and Reineckia carnea were candidates to be used in CWs to effectively remove nitrogen and phosphorus from wastewater. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Enhancement of azo dye Acid Orange 7 removal in newly developed horizontal subsurface-flow constructed wetland. (United States)

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


    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Economic feasibility of surface flow constructed (SFCW) wetlands for reduction of water pollution from agricultural fields in Denmark

    DEFF Research Database (Denmark)

    Gachango, Florence Gathoni; Pedersen, Søren Marcus; Kjaergaard, Charlotte


    Constructed wetlands have been proposed as cost effective and more targeted technologies in the reduction of nitrogen and phosphorous water pollution in drainage losses from agricultural fields in Denmark. Using two pig farms and one dairy farm situated in a pumped lowland catchment as study cases...

  13. Evaluation of nutrient removal efficiency and microbial enzyme activity in a baffled subsurface-flow constructed wetland system (United States)

    Lihua Cui; Ying Ouyang; Wenjie Gu; Weozhi Yang; Qiaoling. Xu


    In this study, the enzyme activities and their relationships to domestic wastewater purification are investigated in four different types of subsurface-flow constructed wetlands (CWs), namely the traditional horizontal subsurface-flow, horizontal baffled subsurface-flow, vertical baffled subsurface-flow, and composite baffled subsurface-flow CWs. Results showed that...

  14. Redox potential dynamics in a horizontal subsurface flow constructed wetland for wastewater treatment: Diel, seasonal ans spatial fluctuations

    Czech Academy of Sciences Publication Activity Database

    Dušek, Jiří; Picek, T.; Čížková, Hana


    Roč. 34, - (2008), s. 223-232 ISSN 0925-8574 Institutional research plan: CEZ:AV0Z60870520 Keywords : Redox potential * Redox prosesses * Phragmites australis * Wastewater treatment s * Constructed wetlands * Contunuous measurement Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.836, year: 2008

  15. Effects of HRT on the efficiency of denitrification and carbon source release in constructed wetland filled with bark. (United States)

    Jiang, Yinghe; Li, Yao; Zhang, Ying; Zhang, Xiangling


    Constructed wetland is widely used to treat municipal sewage. However, lack of carbon source always constraints the application of constructed wetland in advanced tailwater treatment process. Bark was used as the filler and external carbon source of constructed wetland in the study, and the effects of hydraulic retention time (HRT) on NO3--N removal efficiency and carbon release velocity were explored. Results showed that the NO3--N removal process was steady in the constructed wetland filled with bark without additional carbon source. The NO3--N removal efficiency and NO3--N concentration presented a first-order reaction. The reaction rate constant k was 0.4 day-1. The relationship between NO3--N removal efficiency (η) and HRT (t) was η = 1-e-0.4t, and η was increased with increasing of HRT. η reached a maximum of 77% at HRT of 4.48 days. η obtained the minimum of 20% at HRT of 0.75 days. The relationship between the carbon source releasing velocity (v) by bark and HRT was v = 0.53(1.62/t-1/t2) + 0.32. v increased first and then decreased with HRT increasing. The maximum v was detected at t = 1.12 days.

  16. Composting plant leachate treatment by a pilot-scale, three-stage, horizontal flow constructed wetland in central Iran. (United States)

    Bakhshoodeh, Reza; Alavi, Nadali; Paydary, Pooya


    Handling and treatment of composting leachate is difficult and poses major burdens on composting facilities. The main goal of this study was to evaluate usage of a three-stage, constructed wetland to treat leachate produced in Isfahan composting facility. A pilot-scale, three-stage, subsurface, horizontal flow constructed wetland, planted with vetiver with a flow rate of 24 L/day and a 15-day hydraulic retention time, was used. Removal of organic matter, ammonia, nitrate, total nitrogen, suspended solids, and several heavy metals from Isfahan composting facility leachate was monitored over a 3-month period. Constructed wetland system was capable of efficiently removing BOD5 (87.3%), COD (74.5%), ammonia (91.5%), nitrate (87.9%), total nitrogen (87.8%), total suspended solids (85.5%), and heavy metals (ranging from 70 to 90%) from the composting leachate. High contaminant removal efficiencies were achieved, but effluent still failed to meet Iranian standards for treated wastewater. This study shows that although a three-stage horizontal flow constructed wetland planted with vetiver cannot be used alone to treat Isfahan composting facility leachate, but it has the potential to be used as a leachate pre-treatment step, along with another complementary method.

  17. Long-term investigation of constructed wetland wastewater treatment and reuse: Selection of adapted plant species for metaremediation. (United States)

    Saggaï, Mohamed Mounir; Ainouche, Abdelkader; Nelson, Mark; Cattin, Florence; El Amrani, Abdelhak


    A highly diverse plant community in a constructed wetland was used to investigate an ecological treatment system for human wastewater in an arid climate. The eight-year operation of the system has allowed the identification of a highly adapted and effective plant consortium that is convenient for plant-assisted metaremediation of wastewater. This constructed wetland pilot station demonstrated effective performance over this extended period. Originally, there were twenty-five plant species. However, because of environmental constraints and pressure from interspecific competition, only seven species persisted. Interestingly, the molecular phylogenetic analyses and an investigation of the photosynthetic physiology showed that the naturally selected plants are predominately monocot species with C4 or C4-like photosynthetic pathways. Despite the loss of 72% of initially used species in the constructed wetland, the removal efficiencies of BOD, COD, TSS, total phosphorus, ammonia and nitrate were maintained at high levels, approximately 90%, 80%, 94%, 60% and 50%, respectively. Concomitantly, the microbiological water tests showed an extremely high reduction of total coliform bacteria and streptococci, about 99%, even without a specific disinfection step. Hence, the constructed wetland system produced water of high quality that can be used for agricultural purposes. In the present investigation, we provide a comprehensive set of plant species that might be used for long-term and large-scale wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Temporal variation of nitrogen balance within constructed wetlands treating slightly polluted water using a stable nitrogen isotope experiment. (United States)

    Zhang, Wanguang; Lei, Qiongye; Li, Zhengkui; Han, Huayang


    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.

  19. Bioconcentration of triclosan, methyl-triclosan, and triclocarban in the plants and sediments of a constructed wetland. (United States)

    Zarate, Frederick M; Schulwitz, Sarah E; Stevens, Kevin J; Venables, Barney J


    Constructed wetlands are a potential method for the removal of two pharmaceutical and personal care products from wastewater effluent. Triclosan (TCS; 5-chloro-2-[2,4-dichlorophenoxy]phenol) and triclocarban (TCC; 3,4,4'-trichlorocarbanillide) are antimicrobial agents added to a variety of consumer products whose accumulation patterns in constructed wetlands are poorly understood. Here, we report the accumulation of TCS, its metabolite methyl-triclosan (MTCS; 5-chloro-2-[2,4-dichlorophenoxy]), and TCC in wetland plant tissues and sediments. Three wetland macrophytes: Typha latifolia, Pontederia cordata, and Sagittaria graminea were sampled from a constructed wetland in Denton, Texas, USA. MTCS concentrations were below the method detection limit (MDL) for all species. TCS root tissue concentrations in T. latifolia were significantly greater than root concentrations in P. cordata (mean±SE in ng g(-1): 40.3±11.3 vs. 15.0±1.9, respectively), while for TCC, shoot tissue concentrations in S. graminea were significantly greater than in T. latifolia (22.8±9.3 vs. 9.0 (MDL), respectively). For both TCS and TCC, T. latifolia root tissue concentrations were significantly greater than shoot concentrations (TCS: 40.3±11.3 vs. 17.2±0.2, TCC: 26.0±3.6 vs. 9.0, (MDL)). TCC concentrations in P. cordata roots were significantly greater than in shoots (34.4±5.3 vs. 15.4±2.8, respectively). TCS concentrations in T. latifolia roots and sediments and TCC concentrations in sediments generally decreased from wetland inflow to outflow. To our knowledge, this is the first study documenting species and tissue specific differences in the accumulation of TCS and TCC in plants from an operational constructed wetland. The species specific differences in bioaccumulation suggest TCS and TCC removal from constructed wetlands could be enhanced through targeted plantings. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Removal efficiency and balance of nitrogen in a recirculating aquaculture system integrated with constructed wetlands. (United States)

    Zhong, Fei; Liang, Wei; Yu, Tao; Cheng, Shui P; He, Feng; Wu, Zhen B


    The nitrogen (N) balance for aquaculture is an important aspect, especially in China, and it is attributed to the eutrophication in many freshwater bodies. In recent years, constructed wetlands (CWs) have been widely used in wastewater treatment and ecosystem restoration. A recirculating aquaculture system (RAS) consisting of CWs and 4 fish ponds was set up in Wuhan, China. Channel catfish (Ictalurus punctatus) fingerlings were fed for satiation daily for 168 days with 2 diets containing 5.49 % and 6.53 % nitrogen, respectively. The objectives of this study were to investigate the N budget in the RAS, and try to find out the feasibility of controlling N accumulation in the fish pond. It is expected that the study can provide a mass balance for the fate of N in the eco-friendly treatment system to avoid eutrophication. The results showed that the removal rates of ammonia (NH(+)(4)-N), sum of nitrate & nitrite (NO(-)(X)-N), and total nitrogen (TN) by the CWs were 20-55%, 38-84 % and 39-57 %, respectively. Denitrification in the CWs was the main pathway of nitrogen loss (41.67 %). Nitrogen accumulation in pond water and sediment accounted for 3.39 % and 12.65 % of total nitrogen loss, respectively. The nitrogen removal efficiency and budget showed that the CW could be used to control excessive nitrogen accumulation in fish ponds. From the viewpoint of the nitrogen pollution control, the RAS combined with the constructed wetland can be applied to ensure the sustainable development for aquaculture.

  1. Application of the two coupled models for water quality management: facultative pond cum constructed wetland models (United States)

    Mashauri, D. A.; Kayombo, S.

    Recent work has emphasized the potential importance of the constructed wetland systems for purification of effluents from secondary biological treatment plants for prevention of pollution to the receiving water bodies. A model for transformation of organic carbon in facultative pond (FP) was formulated and was coupled with a model of organic carbon transformation in the constructed wetland (CW) for downstream water resources management. The main essence of coupling the model was to have simultaneous simulation of PFP and CW processes. Simultaneous run of the two models imply that the disturbance on parameters in PFP will have a direct effect on CW processes. The model was formulated on the basis fundamental principle that the growth of active biomass in the system defines the transformation of organic carbon. The growth rate of microorganisms was model based on the Monod kinetic equation. The forcing functions to the model were formulated based on multiplicative function. The removal of organic carbon in the FP based on the unfiltered sample was 66% with an average concentration of 206 mg COD/l in the effluent. The removal of organic carbon in the CW was 87.5% with an average concentration of 40 mg COD/l in the effluent. The overall performance of the coupled model was 93%. The main processes of organic carbon removal in the FP and CW were due to uptake by heterotrophic bacteria followed by oxidation. It was found that 80% of the total organic carbon in the CW was due to the biological growth. Oxidation of organic carbon in the PFP was a source of high growth of algae. The constants and coefficients obtained after validation of the model reflect the simultaneous performance of the coupled model of PFP and CW.

  2. Comparison of vertical-flow constructed wetlands with and without supplementary aeration treating decentralized domestic wastewater. (United States)

    Zhu, Liandong; Takala, Josu; Hiltunen, Erkki; Li, Zhaohua; Kristianto, Yohanes


    Constructed wetlands (CWs) are efficient in reducing excessive contamination from wastewaters. However, oxygen inside CW beds is frequently low especially when substrate clogging problems appear after long-term operation, and this may become a limited factor for the treatment of wastewaters. Aimed at dealing with the issue of a low oxygen content in CW systems, two laboratory-scale vertical-flow constructed wetlands (VFCWs) with and without an aeration device (called VFCW-a and VFCW-c, respectively) were designed in this study to test the contribution of supplementary aeration to the treatment of decentralized domestic wastewater. Results showed that under the intermittent operation of about 45 days, two VFCW units were successfully started up by using activated sludge as seed sludge. Compared to VFCW-c, VFCW-a had a better resistance ability to organic shock loads and its removal function could be effectively recovered within a short period after the introduction of organic shock loads. Under intermittent operation with a 12 h idling time, the ideal hydraulic retention time (HRT) of VFCW-a was 42 h, about 6 h shorter than that of VFCW-c. Likewise, under intermittent operation with 42 h HRT, the ideal idling time of VFCW-a was 12 h, still about 6 h shorter than that of VFCW-c. Under intermittent operation with HRT-42 h and an idling time of 12 h, SS, COD, TN and TP removal efficiencies in VFCW-a could reach 81.2%, 85%, 89.9% and 77.9%, respectively. The VFCW unit with supplementary aeration is an efficient innovation for the treatment of decentralized domestic wastewater.

  3. [Studies on nitrogen and phosphorus enhancing removal in combined shale and steel slag subsurface constructed wetlands]. (United States)

    Tan, Hong-Xin; Zhou, Qi; Yang, Dian-Hai


    Effluent of municipal wastewater treatment plant operated under A/O process was treated by constructed wetlands for reclamation and reuse. These methods, such as phosphorus removal by adsorption of shale and steel slag, regulating C/N ratio and nitrogen oxidability in influent of wetland, were employed to study efficiency and impact factors of nitrogen and phosphorus removal in pilot-scale in combined shale and steel slag subsurface constructed wetlands. Results indicate that, When COD area load rate, TN area load rate, TP area load rate and hydraulic retention time (HRT) is 6.5-20.7 g x (m2 x d)(-1), 2.57-8.22 g x (m2 x d)(-1), 0.41 -1.32 g x (m2 x d)(-1) and 0.5- 1.6d, respectively. Removal efficiency of ammonium nitrogen, nitrite nitrogen and nitrate nitrogen is 85.8%, 56.3% and 18.6%, respectively. Removal efficiency, area load removal rate and removal kinetic constant of total nitrogen are 58.0%, 3.58 g x (m2 x d)(-1) and 0.31m x d(-1), respectively. TN area load removal rate is linearly increased with the increase of total nitrogen area load rate. Removal efficiency, area load removal rate and removal kinetic constant of total phosphorus are 90.4%, 0.89 g x (m2 x d)(-1) and 0.86 m x d(-1), respectively. TP area load removal rate is linearly increased with the increase of total phosphorus area load rate. Water temperature, HRT, COD/TN ratio and (NO2(-) -N + NO3(-) -N) /TN ratio are primary factors impacting nitrogen and phosphorus area load removal rate. Along with HRT and COD/TN ratio increase, TN area load removal rate increases according to power function. Along with water temperature and (NO2(-) -N + NO3(-) -N)/TN ratio increase, TN area load removal rate increases according to exponential function.

  4. Graph construction using adaptive Local Hybrid Coding scheme. (United States)

    Dornaika, Fadi; Kejani, Mahdi Tavassoli; Bosaghzadeh, Alireza


    It is well known that dense coding with local bases (via Least Square coding schemes) can lead to large quantization errors or poor performances of machine learning tasks. On the other hand, sparse coding focuses on accurate representation without taking into account data locality due to its tendency to ignore the intrinsic structure hidden among the data. Local Hybrid Coding (LHC) (Xiang et al., 2014) was recently proposed as an alternative to the sparse coding scheme that is used in Sparse Representation Classifier (SRC). The LHC blends sparsity and bases-locality criteria in a unified optimization problem. It can retain the strengths of both sparsity and locality. Thus, the hybrid codes would have some advantages over both dense and sparse codes. This paper introduces a data-driven graph construction method that exploits and extends the LHC scheme. In particular, we propose a new coding scheme coined Adaptive Local Hybrid Coding (ALHC). The main contributions are as follows. First, the proposed coding scheme adaptively selects the local and non-local bases of LHC using data similarities provided by Locality-constrained Linear code. Second, the proposed ALHC exploits local similarities in its solution. Third, we use the proposed coding scheme for graph construction. For the task of graph-based label propagation, we demonstrate high classification performance of the proposed graph method on four benchmark face datasets: Extended Yale, PF01, PIE, and FERET. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Biogeochemical Processes Related to Metal Removal and Toxicity Reduction in the H-02 Constructed Wetland, Savannah River Site (United States)

    Burgess, E. A.; Mills, G. L.; Harmon, M.; Samarkin, V.


    The H-02 wetland system was designed to treat building process water and storm water runoff from multiple sources associated with the Tritium Facility at the DOE-Savannah River Site, Aiken, SC. The wetland construction included the addition of gypsum (calcium sulfate) to foster a sulfate-reducing bacterial population. Conceptually, the wetland functions as follows: ? Cu and Zn initially bind to both dissolved and particulate organic detritus within the wetland. ? A portion of this organic matter is subsequently deposited into the surface sediments within the wetland. ? The fraction of Cu and Zn that is discharged in the wetland effluent is organically complexed, less bioavailable, and consequently, less toxic. ? The Cu and Zn deposited in the surface sediments are eventually sequestered into insoluble sulfide minerals in the wetland. Development of the H-02 system has been closely monitored; sampling began in August 2007, shortly after its construction. This monitoring has included the measurement of water quality parameters, Cu and Zn concentrations in surface water and sediments, as well as, characterization of the prokaryotic (e.g., bacterial) component of wetland biogeochemical processes. Since the beginning of the study, the mean influent Cu concentration was 31.5±12.1 ppb and the mean effluent concentration was 11.9±7.3 ppb, corresponding to an average Cu removal of 64%. Zn concentrations were more variable, averaging 39.2±13.8 ppb in the influent and 25.7±21.3 ppb in the effluent. Average Zn removal was 52%. The wetland also ameliorated high pH values associated with influent water to values similar to those measured at reference sites. Seasonal variations in DOC concentration corresponded to seasonal variations in Cu and Zn removal efficiency. The concentration of Cu and Zn in the surface layer of the sediments has increased over the lifetime of the wetland and, like removal efficiency, demonstrated seasonal variation. Within its first year, the H-02

  6. Pemanfaatan Constructed Wetland Sebagai Bagian Dari Rancangan Lansekap Ruang Publik Yang Berwawasan Ekologis Studi Kasus Houtan Park China

    Directory of Open Access Journals (Sweden)

    Barito Adi Buldan Rayaganda Rito


    Full Text Available Kebutuhan akan air bersih merupakan salah satu permasalahan lingkungan yang sering terjadi. Hal ini sejalan dengan kebutuhan akan kualitas lingkungan yang lebih baik, khususnya dalam kasus ruang luar atau lansekap. Lansekap berbasis suasana air merupakan satu bentuk ruang luar yang memiliki keistimewaan sekaligus tantangan, terkait kualitas air dan model pembersihannya. Dari berbagai metode pembersihan air yang ada, Constructed Wetland merupakan suatu bentuk pembersihan kondisi air alamiah dengan meniru wetland alamiah baik dari segi struktur pewadahannya maupun vegetasi – vegetasi yang digunakan.Paper ini bertujuan untuk mengetahui penerapan upaya pembersihan air secara alami menggunakan metode constructed wetland, dan melihat pemanfaatan metode ini dalam integrasinya dengan rancangan lansekap. Penelitian bersifat kualitatif dengan Metode penelitian deskriptif, melalui studi literature dan kasus di Houtan Park, China.Dari hasil penelitian ini disimpulkan bahwa sebagai pilihan metode pembersihan air secara alamiah, ruang dan suasana yang tercipta dari sistem ini berpotensi untuk dikembangkan menjadi bagian dari konsep rancangan lansekap. Dalam studi kasus di Houtan park, Shanghai, China, constructed wetland tidak hanya dimanfaatkan sebagai sarana pembersihan air, namun menjadi bagian dari area lansekap ruang publik yang dapat dinikmati dan membuat pengunjung lebih dekat dengan alam dan lingkungan yang berkualitas.

  7. Ammonia, phosphate, phenol, and copper(II) removal from aqueous solution by subsurface and surface flow constructed wetland. (United States)

    Mojiri, Amin; Ahmad, Zakiah; Tajuddin, Ramlah Mohd; Arshad, Mohd Fadzil; Gholami, Ali


    Water pollution is a global problem. During current study, ammonia, phosphate, phenol, and copper(II) were removed from aqueous solution by subsurface and surface flow constructed wetland. In current investigation, distilled water was polluted with four contaminants including ammonia, phosphate, copper (Cu), and phenol. Response surface methodology and central composite design were applied to optimize pollutant removal during treatment by subsurface flow constructed wetland (SSFCW). Contact time (12 to 80 h) and initial pollutant concentration (20 to 85 mg/L) were selected as independent factors; some upper and lower ranges were also monitored for accuracy. In SSFCW, water hyacinth transplanted in two substrate layers, namely zeolite and cockle shell. SSFCW removed 87.7, 81.4, 74.7, and 54.9% of ammonia, phosphate, Cu, and phenol, respectively, at optimum contact time (64.5 h) and initial pollutant concentration (69.2 mg/L). Aqueous solution was moved to a surface flow constructed wetland (SFCW) after treating via SSFCW at optimum conditions. In SFCW, Typha was transplanted to a fixed powdered substrate layer, including bentonite, zeolite, and cockle shell. SFCW could develop performance of this combined system and could improve elimination efficacy of the four contaminants to 99.99%. So this combined CW showed a good performance in removing pollutants. Graphical abstract Wetlands arrangement for treating aqueous solution in current study.

  8. Emerging organic contaminant removal depending on primary treatment and operational strategy in horizontal subsurface flow constructed wetlands: influence of redox. (United States)

    Avila, Cristina; Reyes, Carolina; Bayona, Josep María; García, Joan


    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

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

    Energy Technology Data Exchange (ETDEWEB)

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


    This paper investigates the use of flue gas desulfurization (FGD) by-products from 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.

  10. Overview of the state of the art of constructed wetlands for decentralized wastewater management in Brazil. (United States)

    Machado, A I; Beretta, M; Fragoso, R; Duarte, E


    Conventional wastewater treatment plants (WWTPs) commonly require large capital investments as well as operation and maintenance costs. Constructed wetlands (CWs) appear as a cost-effective treatment, since they can remove a broad range of contaminants by a combination of physical, chemical and biological processes with a low cost. Therefore, CWs can be successfully applied for decentralized wastewater treatment in regions with low population density and/or with large land availability as Brazil. The present work provides a review of thirty nine studies developed on CWs implemented in Brazil to remove wastewater contaminants. Brazil current sanitation data is also considered to evaluate the potential role of CWs as decentralized wastewater treatment. Performance of CWs was evaluated according to (i) type of wetland system, (ii) different support matrix (iii) vegetation species and (iv) removal efficiency of chemical oxygen demand (COD), biological oxygen demand (BOD5), nitrogen (N), and phosphorus (P). The reviewed CWs in overall presented good efficiencies, whereas H-CWs achieved the highest removals for P, while the higher results for N were attained on VF-CW and for COD and BOD5 on HF-CW. Therefore, was concluded that CWs are an interesting solution for decentralized wastewater treatment in Brazil since it has warm temperatures, extensive radiation hours and available land. Additionally, the low percentage of population with access to the sewage network in the North and Northeast regions makes these systems especially suitable. Hence, the further implementation of CW is encouraged by the authors in regions with similar characteristics as Brazil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Constructed Wetlands for Agricultural Wastewater Treatment in Northeastern North America: A Review

    Directory of Open Access Journals (Sweden)

    Eric R. Rozema


    Full Text Available Constructed wetlands (CW are a treatment option for agricultural wastewater. Their ability to adequately function in cold climates continues to be evaluated as they are biologically active systems that depend on microbial and plant activity. In order to assess their performance and to highlight regional specific design considerations, a review of CWs in Eastern Canada and the Northeastern USA was conducted. Here, we synthesize performance data from 21 studies, in which 25 full-scale wetlands were assessed. Where possible, data were separated seasonally to evaluate the climatic effects on treatment performance. The wastewater parameters considered were five-day biochemical oxygen demand (BOD5, total suspended solids (TSS, E. coli, fecal coliforms, total Kjeldahl nitrogen (TKN, ammonia/ammonium (NH3/NH4+-N, nitrate-nitrogen (NO3−-N, and total phosphorus (TP. Average concentration reductions were: BOD5 81%, TSS 83%, TKN 75%, NH4+-N 76%, NO3−-N 42%, and TP 64%. Average log reductions for E. coli and fecal coliforms were 1.63 and 1.93, respectively. Average first order areal rate constants (ka, m·y−1 were: BOD5 6.0 m·y−1, TSS 7.7 m·y−1, E. coli 7.0 m·y−1, fecal coliforms 9.7 m·y−1, TKN 3.1 m·y−1, NH4+-N 3.3 m·y−1, NO3−-N 2.5 m·y−1, and TP 2.9 m·y−1. In general, CWs effectively treated a variety of agricultural wastewaters, regardless of season.

  12. Management and treatment of landfill leachate by a system of constructed wetlands and ponds in Singapore. (United States)

    Sim, C H; Quek, B S; Shutes, R B E; Goh, K H


    Lorong Halus, Singapore's first landfill leachate treatment system, consists of a pre-treatment system (8,000 m(2)), five constructed reed beds (38,000 m(2)), five polishing ponds (13,000 m(2)), an education centre and a learning trail for visitors. Eight species of wetland plants (total 160,000 plants) were selected for their ability to uptake nutrients, tolerance to low phosphorus concentrations and resistance to pest infestations. The wetland was launched in March 2011 and water quality monitoring started in April 2011. The removal efficiencies of the pre-treatment system from April 2011 to August 2012 are biochemical oxygen demand (BOD5) 57.4%; chemical oxygen demand (COD) 23.6%; total suspended solids (TSS) 55.1%; ammoniacal nitrogen (NH4-N) 76.8%; total phosphorus (TP) 33.3% and total nitrogen (TN) 60.2%. Removal efficiencies of the reed beds are BOD5 47.0%; COD 42.2%; TSS 57.0%; NH4-N 82.5%; TP 29.3% and TN 83.9%. Plant growth is generally satisfactory, but the lower than designed volume of leachate has adversely affected some sections of plants and resulted in uneven flow distribution in reed beds. The plant management programme includes improving plant regrowth by harvesting of alternate strips of plants and replanting. The treated effluent meets water quality limits for discharge to the public sewer and is subsequently treated by the NEWater treatment system, which recycles water for industrial and indirect potable use.

  13. Removal of the pesticides imazalil and tebuconazole in saturated constructed wetland mesocosms. (United States)

    Lv, Tao; Zhang, Yang; Zhang, Liang; Carvalho, Pedro N; Arias, Carlos A; Brix, Hans


    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Performance of a pilot-scale, three-stage constructed wetland system for domestic wastewater treatment. (United States)

    Tunçsiper, Bilal; Ayaz, Selma; Akça, Lütfi; Gunes, Kemal


    This study investigates the effects of season, organic matter loadings, hydraulic conditions, recycling, and rapid drainage on water quality in a pilot-scale, three-stage subsurface flow constructed wetland (SSF CW) system. The pilot CW system consisted of a vertical flow-gravel filtration (v-GF) wetland in the first stage, a horizontal-subsurface flow (h-SSF) bed planted with Iris in the second stage, and a vertical-subsurface flow (v-SSF) bed vegetated with Phragmites in the third stage. The objective of this study was to evaluate the potential of these CW systems to remove organic matter from domestic wastewater on a pilot-scale three-stage SSF CW system. Comparisons of average influent and effluent concentrations showed that the multistage system could effectively reduce total suspended solids (TSS), biological oxygen demand (BOD) and chemical oxygen demand (COD) levels in effluent by as much as 98% and total organic carbon (TOC) by as much as 79%. Contributions of the first, second and third stages to the overall treatment were approximately 10%, 45% and 45%, respectively. The average TSS, COD, and TOC concentrations were reduced in the entire CW system by 70%, 80% and 90%, respectively. The BOD and TOC removal efficiencies displayed seasonal variations with average removals generally increasing in warmer seasons. Our results also demonstrate that there were strong correlations between removal efficiencies and loading rates. Average removals decreased with an increase in the hydraulic retention time (HRT). The rapid drainage and recycling operation increased the efficiency of BOD removal only.

  15. Performance of a vertical subsurface flow constructed wetland under different operational conditions

    Directory of Open Access Journals (Sweden)

    Sara G. Abdelhakeem


    Full Text Available The performance of a vertical subsurface flow constructed wetland (VSSFCW for sewage effluent treatment was studied in an eight month experiment under different operational conditions including: vegetation (the presence or absence of common reeds “Phragmites australis”, media type (gravel or vermiculite, and mode of sewage feeding (continuous or batch. Plants had a significant effect (P < 0.05 on the removal efficiency and mass removal rate of all pollutants, except phosphorous. The average removal efficiencies of chemical oxygen demand (COD, biological oxygen demand (BOD, total suspended solids (TSS, ammonium (NH4 and total-P (TP were 75%, 84%, 75%, 32% and 22% for the planted beds compared to 29%, 37%, 42%, 26% and 17%, respectively, for the unplanted beds. The VSSFCW was ineffective in removing nitrate (NO3. The effect of either media type or feeding mode system on the removal efficiency of COD and BOD was insignificant. Vermiculite media significantly (P < 0.05 increased the efficiency of the wetland in removing NH4, TP and dissolved phosphorous (DP when compared with gravel particularly in the planted beds. The batch mode was more effective in removing TSS and NH4 compared to the continuous mode. Volumetric rate constant (kV was different for various pollutants and significantly increased due to the presence of plants. Media type had no significant effect on the values of kV for COD, BOD and TSS, while kV for NH4 and TP under vermiculite in the planted beds and kV for P in the unplanted beds were significantly higher than those under gravel.

  16. Selection of wild macrophytes for use in constructed wetlands for phytoremediation of contaminant mixtures. (United States)

    Guittonny-Philippe, Anna; Petit, Marie-Eléonore; Masotti, Véronique; Monnier, Yogan; Malleret, Laure; Coulomb, Bruno; Combroux, Isabelle; Baumberger, Teddy; Viglione, Julien; Laffont-Schwob, Isabelle


    Constructed wetlands (CWs) offer an alternative to traditional industrial wastewater treatment systems that has been proved to be efficient, cost-effective and environmentally friendly. Most of the time, CWs are planted with proliferative species such as Phragmites australis or with plants originating from nurseries, both representing a risk for the natural biodiversity conservation of aquatic ecosystems located downstream of the CWs. For the removal of metals and organic pollutant mixtures present in industrial effluents, it is necessary to select tolerant plant species that are able to produce a high aboveground biomass and to develop a healthy belowground system. Wild plant species growing in aquatic bodies at industrial outfalls could constitute suitable tolerant species to use in CWs for industrial effluent treatment. To test this hypothesis, we assessed, under laboratory conditions (using an experimental design), the tolerance to mixtures of metals (Al, As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Sn, Zn) or/and organic pollutants (THC, PHE, PYR, LAS) of five European sub-cosmopolitan native macrophytes (Alisma lanceolatum, Carex cuprina, Epilobium hirsutum, Iris pseudacorus and Juncus inflexus) that had been collected in a polluted Mediterranean wetland, after a field study (crossing ecological relevés and analyses of contaminant concentrations in water and sediments). Our results demonstrated that research on phytoremediation of industrial effluents should focus much more on the use of native macrophytes growing at short distances from industrial discharges (such as C. cuprina in this study), and that root/shoot ratio, aerial height and proportion of green leaves are good and cost-effective indicators of plant tolerance to metals and organic pollutant mixtures in laboratory studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Bioprinting of hybrid tissue constructs with tailorable mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Schuurman, W; Khristov, V; Pot, M W; Dhert, W J A; Malda, J [Department of Orthopaedics, University Medical Center Utrecht (Netherlands); Van Weeren, P R, E-mail: [Faculty of Veterinary Sciences, Department of Equine Sciences, Utrecht University (Netherlands)


    Tissue/organ printing aims to recapitulate the intrinsic complexity of native tissues. For a number of tissues, in particular those of musculoskeletal origin, adequate mechanical characteristics are an important prerequisite for their initial handling and stability, as well as long-lasting functioning. Hence, organized implants, possessing mechanical characteristics similar to the native tissue, may result in improved clinical outcomes of regenerative approaches. Using a bioprinter, grafts were constructed by alternate deposition of thermoplastic fibers and (cell-laden) hydrogels. Constructs of different shapes and sizes were manufactured and mechanical properties, as well as cell viability, were assessed. This approach yields novel organized viable hybrid constructs, which possess favorable mechanical characteristics, within the same range as those of native tissues. Moreover, the approach allows the use of multiple hydrogels and can thus produce constructs containing multiple cell types or bioactive factors. Furthermore, since the hydrogel is supported by the thermoplastic material, a broader range of hydrogel types can be used compared to bioprinting of hydrogels alone. In conclusion, we present an innovative and versatile approach for bioprinting, yielding constructs of which the mechanical stiffness provided by thermoplastic polymers can potentially be tailored, and combined specific cell placement patterns of multiple cell types embedded in a wide range of hydrogels. (communication)

  18. Chromium removal from wastewater using HSF and VF pilot-scale constructed wetlands: Overall performance, and fate and distribution of this element within the wetland environment. (United States)

    Papaevangelou, Vassiliki A; Gikas, Georgios D; Tsihrintzis, Vassilios A


    The current experimental work aimed at the investigation of the overall chromium removal capacity of constructed wetlands (CWs) and the chromium fate-distribution within a wetland environment. For this purpose, the experimental setup included the parallel operation and monitoring of two horizontal subsurface flow (HSF) pilot-scale CWs and two vertical flow (VF) pilot-scale CWs treating Cr-bearing wastewater. Samples were collected from the influent, the effluent, the substrate and the plants. Apart from the continuous experiment, batch experiments (kinetics and isotherm) were conducted in order to investigate the chromium adsorption capacity of the substrate material. According to the findings, HSF-CWs demonstrated higher removal capacities in comparison to VF-CWs, while in both types the planted units indicated better performance compared to the unplanted ones. Analysis in various wetland compartments and annual mass balance calculation highlighted the exceptional contribution of substrate to chromium retention, while Cr accumulation in plant was not so high. Finally, experimental data fitted better to the pseudo-second-order and Langmuir models regarding kinetics and isotherm simulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Gas production, oxygen demand and microbial activity in sediments of wetlands constructed with oil sands mine tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, M.; Weisener, C.; Ciborowski, J.; Slama, C.; Costa, J. [Windsor Univ., ON (Canada); Goudey, S. [HydroQual, Calgary, AB (Canada)


    Changes in sediment oxygen demand (SOD) in 2 reference and 9 oil sands process material (OSPM) impacted wetlands were evaluated. The wetlands were constructed in 1992. SOD was measured by determining the rate of O{sub 2} depletion in in-situ test chambers placed on the sediment surface within the test pond areas. The study showed that SOD measurements conducted in 2008-2009 showed a slower rate of oxygen consumption than measurements conducted in 1993. Results suggested that sediment-associated reducing compounds were depleted. Carbon dioxide (CO{sub 2}) was dominantly respired by methanogens using the carbon as a terminal electron acceptor in conjunction with hydrogen to produce methane (CH{sub 4}). Gases analyzed in situ from the wetland sediments suggested that OSPM-affected sediments promote the growth of methanogenic bacteria. Samples of evolved gas, pore water, and intact sediment cores were collected at each wetland site in order to determine if significant differences in biogeochemical composition have developed. Further research is being conducted to characterize the relationship between the microbes and the sediments of the reclaimed wetlands.

  20. Nitrogen removal performance in planted and unplanted horizontal subsurface flow constructed wetlands treating different influent COD/N ratios. (United States)

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


    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.

  1. Assessment of diazinon toxicity in sediment and water of constructed wetlands using deployed Corbicula fluminea and laboratory testing. (United States)

    Bouldin, J L; Farris, J L; Moore, M T; Smith, S; Cooper, C M


    Constructed wetlands for mitigation of nonpoint agricultural runoff have been assessed for their ability to decrease potential toxicity from associated contaminants. After a simulated runoff event, constructed wetlands positioned in series were used to measure the effects of the organophosphate insecticide diazinon. Water, sediment, and plant samples from five sites were analyzed for diazinon concentrations from 0.5 hours to 26 days; peak concentrations were measured in sediment after 0.5 hours (268.7 microg/kg) and in water and plant tissue after 3 hours (121.71 microg/L and 300.7 microg/kg, respectively). Cholinesterase activity and changes in shell growth were measured from Corbicula fluminea deployed at corresponding sites. Water collected after 9 hours from all wetland sites contained diazinon concentrations sufficient to cause toxicity to Ceriodaphnia dubia, but not to Pimephales promelas. C. dubia survival was decreased in water sampled through 7 days from the site nearest runoff introduction, whereas C. fluminea deployed at this same site experienced 100% mortality after 26 days. Clams from lower sites survived wetland conditions, but growth and ChE activity were significantly decreased lower than that of clams from a control site. C. dubia exposed to water from these sites continued to have decreased survival throughout the 26-day sampling. Sediment sampled from 48 hours through 14 days at the lowest wetland site decreased the laboratory survival of Chironomus dilutus, and sediment from upper sites elicited an effect only on day 26. Although wetland concentrations of aqueous diazinon were decreased lower than toxic thresholds after 26 days, decreased ChE activity in deployed clams provided evidence of residual diazinon effects to deployed organisms.

  2. Bioavailability and fate of phosphorus in constructed wetlands receiving agricultural runoff in the San Joaquin Valley, California. (United States)

    Maynard, Jonathan J; O'Geen, Anthony T; Dahlgren, Randy A


    Elevated nutrient concentrations in agricultural runoff contribute to seasonal eutrophication and hypoxia in the lower portion of the San Joaquin River, California. Interception and filtration of agricultural runoff by constructed wetlands may improve water quality of return flows ultimately destined for major water bodies. This study evaluated the efficacy of two small flow-through wetlands (2.3 and 7.3 ha; hydraulic residence time = 11 and 31 h) for attenuating various forms of P from irrigation tailwaters during the 2005 irrigation season (May to September). Our goal was to examine transformations and removal efficiencies for bioavailable P in constructed wetlands. Inflow and outflow water volumes were monitored continuously and weekly water samples were collected to measure total P (TP), dissolved-reactive P (DRP), and bioavailable P (BAP). Suspended sediment was characterized and fractionated into five operationally-defined P fractions (i.e., NH4Cl, bicarbonate-dithionite, NaOH, HCl, residual) to evaluate particulate P (PP) transformations. DRP was the major source of BAP with the particulate fraction contributing from 11 to 26%. On a seasonal basis, wetlands removed 55 to 65% of PP, 61 to 63% of DRP, 57 to 62% of BAP, and 88 to 91% of TSS. Sequential fractionation indicated that the bioavailable fraction of PP was largely associated with clay-sized particles that remain in suspension, while less labile P forms preferentially settle with coarser sediment. Thus, removal of potentially bioavailable PP is dependent on factors that promote particle settling and allow for the removal of colloids. This study suggests that treatment of tailwaters in small, flow-through wetlands can effectively remove BAP. Wetland design and management strategies that enhance sedimentation of colloids can improve BAP retention efficiency.

  3. Construction of gateway-compatible yeast two-hybrid vectors for ...

    African Journals Online (AJOL)

    Yeast two-hybrid system combined with the gateway technology will greatly facilitate the cloning of interested DNA fragment into yeast two-hybrid vectors and therefore increase the efficiency of yeast two-hybrid analysis. In this study, we constructed a pair of Gateway-compatible yeast two-hybrid vectors pBTM116GW and ...

  4. Optimal maintenance of constructed wetlands using an environmental decision support system. (United States)

    Turon, C; Alemany, J; Bou, J; Comas, J; Poch, M


    Constructed wetlands (CWs) are artificial wastewater treatment systems appropriate for small communities because of their affordability, operability and reliability. These qualities are true whenever CWs are designed and constructed properly, and as long as the necessary operation and maintenance procedures are carried out correctly. Experience shows that the operation and maintenance procedures, and the frequencies with which these procedures are carried out, differ from one CW to another. With this in mind, and along with a projected increase in CWs in Catalonia, the Catalan Water Agency (Agència Catalana de l'Aigua) has developed an Environmental Decision Support System (EDSS) which proposes guidelines for monitoring and maintenance, according to the characteristics of each CW. This EDSS was developed following a methodology based on five steps: (i) problem analysis; (ii) collecting data and knowledge acquisition; (iii) model selection; (iv) model implementation and (v) validation. This paper describes the methodology followed to build the decision support system and presents some examples of the information provided by this EDSS.

  5. [Study on phosphorus removal capability of constructed wetlands filled with broken bricks]. (United States)

    Wang, Zhen; Liu, Chao-Xiang; Li, Peng-Yu; Dong, Jian; Liu, Lin; Zhu, Ge-Fu


    Physico-chemical properties of broken bricks (BB) were determined, as well as its phosphorus adsorption ability. The results showed that BB was appropriate for enrichment of microorganisms and growth of plants as filter medium in CWs, in addition, BB had high phosphorus adsorption ability. A vertical subsurface flow constructed wetland (VSSF) filled with BB was constructed in order to investigate the phosphorus removal effect of domestic sewage, and the phosphorus removal mechanism of VSSF was also explored. The results showed that the phosphorus removal rate of VSSF was more than 90%, which remained stable when the hydraulic loading rate was 5 cm x d(-1) and the running time was 1 a; adsorption and precipitation within BB played the greatest role in phosphorus removal; distribution characteristics of total phosphorus in the filter media were attributed to the vertical flow state of wastewater in the system, besides, the contents and chemical forms of elements which could precipitate with phosphorus should be principal factors for the phosphorus removal processes of BB. Therefore, BB might be an ideal filter medium used in CWs.

  6. Comparison of constructed wetland and stabilization pond for the treatment of digested effluent of swine wastewater. (United States)

    Liu, Gang-Jin; Zheng, Dan; Deng, Liang-Wei; Wen, Quan; Liu, Yi


    A laboratory-scale horizontal subsurface flow constructed wetland (HSFCW) and a stabilization pond (SP) were constructed to compare their performances on the treatment of digested effluent of swine wastewater. After 457 days of operation, the removal efficiencies of the HSFCW were as follows: chemical oxygen demand (COD), 17-54%; total phosphorus (TP), 32-45% and ammonia nitrogen [Formula: see text], 27-88%, while they were 25-55%, 31-56% and 56-98%, respectively, for the SP, with a hydraulic retention time of 54 days and hydraulic loading of 0.01 m³ m⁻² d⁻¹. The average removed loads for the HSFCW were as follows: COD, 0.25-4.33; TP, 0.01-0.11 and [Formula: see text], 0.34-2.54 g m⁻² d⁻¹, while they were 0.25-4.45, 0.02-0.13 and 0.72-2.87 g m⁻² d⁻¹, respectively, for the SP. The SP performed better than the HSFCW because the SP showed a 20% of higher removal efficiency for [Formula: see text] than the HSFCW. Especially, the COD removal rate of SP was 10% higher than the HSFCW when the influent concentration was at the lowest and highest stages. Meanwhile, given the lower costs, the SP is more suitable for the treatment of digested effluent of swine wastewater than the HSFCW.

  7. Constructed wetlands combined with UV disinfection systems for removal of enteric pathogens and wastewater contaminants. (United States)

    Azaizeh, H; Linden, K G; Barstow, C; Kalbouneh, S; Tellawi, A; Albalawneh, A; Gerchman, Y


    Water shortage is an ongoing cardinal issue in the Middle East region. Wastewater reuse offers some remediation, but to-date many rural communities in the Palestinian Authority (PA) and in Jordan are not connected to centralized wastewater treatment plants (WWTPs), many of them are disposing of their wastewater using infiltration septic tanks. This highlights the need for a small, local, low cost WWTP that can directly benefit local communities, producing effluents suitable for unrestricted irrigation. Constructed wetlands (CWs) could offer a solution as they are relatively easy and cheap to construct and maintain, and effective in removal of many pollutants. Nevertheless, pathogen removal in CWs is often not adequate, calling for additional disinfection. Here we describe the use of low-cost, consumer level, UV based disinfection systems coupled to CWs for wastewater treatment in three CWs: in Israel, Jordan and in the PA. Once mature, our adapted CWs reduced chemical oxygen demand (COD) load, and, given proper use of the UV systems, inactivated indicator bacteria (faecal and E. coli) to levels suitable for irrigation, even when UV transmission (UVT) levels were low (∼40%). Our results demonstrate the promise in this combined treatment technique for cheap and simple wastewater treatment suitable for the Middle East region.

  8. Development of a horizontal subsurface flow modular constructed wetland for urban runoff treatment. (United States)

    Choi, J Y; Maniquiz, M C; Geronimo, F K; Lee, S Y; Lee, B S; Kim, L H


    Constructed wetlands (CWs) are well recognized as having low construction and maintenance cost and low energy requirement. However, CW design has been mainly based on rule-of-thumb approaches. In this study, the efficiency of a modular horizontal subsurface flow (HSSF) CW using four different design schemes was investigated. Based on the results, the four systems have attained more than 90% removal of total suspended solids and more than 50% removal efficiency for total phosphorus, PO(4)-P and Zn. The planted system achieved higher pollutant removal rates than the unplanted system. In terms of media, bottom ash was more effective than woodchip in reducing the pollutants. Considering the flow length, optimum removal efficiency was achieved after passing the sedimentation tank and vertical media layer; with respect to depth, more pollutants were removed in the upper sand layer than in the lower gravel layer. This study recommended a surface area of 0.25 to 0.8% of catchment area for planted CW and 0.26 to 0.9% for unplanted CW using the 7.5 to 10 mm design rainfall.

  9. Flight distance of mosquitoes (Culicidae): A metadata analysis to support the management of barrier zones around rewetted and newly constructed wetlands

    NARCIS (Netherlands)

    Verdonschot, P.F.M.; Besse-Lototskaya, A.A.


    Society responds to changes in climate and land use via mitigation measures, including rainwater retention and storage in rewetted and newly constructed wetlands. Humans living close to these wetlands express concerns about future mosquito nuisance situations, and request the necessary distance

  10. Effects of substratum on the diversity and stability of ammonia-oxidising communities in a constructed wetland used for wastewater treatment

    NARCIS (Netherlands)

    Gorra, R.; Coci, M.; Ambrosoli, R.; Laanbroek, R.


    Aim: To study the relationship between the nature of the substratum and the diversity and stability of the ammonia-oxidizing microbial community in a constructed wetland for the treatment of wastewaters. Methods and Results: Samples have been taken the year around from sections of the wetland filled

  11. Operational, design and microbial aspects related to power production with microbial fuel cells implemented in constructed wetlands. (United States)

    Corbella, Clara; Guivernau, Miriam; Viñas, Marc; Puigagut, Jaume


    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Purifying capability, enzyme activity, and nitrification potentials in December in integrated vertical flow constructed wetland with earthworms and different substrates. (United States)

    Xu, Defu; Gu, Jiaru; Li, Yingxue; Zhang, Yu; Howard, Alan; Guan, Yidong; Li, Jiuhai; Xu, Hui


    The response of purifying capability, enzyme activity, nitrification potentials, and total number of bacteria in the rhizosphere in December to wetland plants, substrates, and earthworms was investigated in integrated vertical flow constructed wetlands (IVFCW). The removal efficiency of total nitrogen (TN), NH4-N, chemical oxygen demand (COD), and total phosphorus (TP) was increased when earthworms were added into IVFCW. A significantly average removal efficiency of N in IVFCW that employed river sand as substrate and in IVFCW that employed a mixture of river sand and Qing sand as substrate was not found. However, the average removal efficiency of P was higher in IVFCW with a mixture of river sand and Qing sand as substrate than in IVFCW with river sand as substrate. Invertase activity in December was higher in IVFCW that used a mixture of river sand and Qing sand as substrate than in IVFCW which used only river sand as substrate. However, urease activity, nitrification potential, and total number of bacteria in December was higher in IVFCW that employed river sand as substrate than in IVFCW with a mixture of river sand and Qing sand as substrate. The addition of earthworms into the integrated vertical flow constructed wetland increased the above-ground biomass, enzyme activity (catalase, urease, and invertase), nitrification potentials, and total number of bacteria in December. The above-ground biomass of wetland plants was significantly positively correlated with urease and nitrification potentials (p nitrification potentials in December, which resulted in improving purifying capability.

  13. Using sorbent waste materials to enhance treatment of micro-point source effluents by constructed wetlands (United States)

    Green, Verity; Surridge, Ben; Quinton, John; Matthews, Mike


    Sorbent materials are widely used in environmental settings as a means of enhancing pollution remediation. A key area of environmental concern is that of water pollution, including the need to treat micro-point sources of wastewater pollution, such as from caravan sites or visitor centres. Constructed wetlands (CWs) represent one means for effective treatment of wastewater from small wastewater producers, in part because they are believed to be economically viable and environmentally sustainable. Constructed wetlands have the potential to remove a range of pollutants found in wastewater, including nitrogen (N), phosphorus (P), biochemical oxygen demand (BOD) and carbon (C), whilst also reducing the total suspended solids (TSS) concentration in effluents. However, there remain particular challenges for P and N removal from wastewater in CWs, as well as the sometimes limited BOD removal within these treatment systems, particularly for micro-point sources of wastewater. It has been hypothesised that the amendment of CWs with sorbent materials can enhance their potential to treat wastewater, particularly through enhancing the removal of N and P. This paper focuses on data from batch and mesocosm studies that were conducted to identify and assess sorbent materials suitable for use within CWs. The aim in using sorbent material was to enhance the combined removal of phosphate (PO4-P) and ammonium (NH4-N). The key selection criteria for the sorbent materials were that they possess effective PO4-P, NH4-N or combined pollutant removal, come from low cost and sustainable sources, have potential for reuse, for example as a fertiliser or soil conditioner, and show limited potential for re-release of adsorbed nutrients. The sorbent materials selected for testing were alum sludge from water treatment works, ochre derived from minewater treatment, biochar derived from various feedstocks, plasterboard and zeolite. The performance of the individual sorbents was assessed through

  14. Effect of different plant species in pilot constructed wetlands for wastewater reuse in agriculture

    Directory of Open Access Journals (Sweden)

    Salvatore Barbagallo


    Full Text Available In this paper the first results of an experiment carried out in Southern Italy (Sicily on the evapotranspiration (ET and removal in constructed wetlands with five plant species are presented. The pilot plant used for this study is made of twelve horizontal sub-surface flow constructed wetlands (each with a surface area of 4.5 m2 functioning in parallel, and it is used for tertiary treatment of part of the effluents from a conventional municipal wastewater treatment plant (trickling filter. Two beds are unplanted (control while ten beds are planted with five different macrophyte species: Cyperus papyrus, Vetiveria zizanoides, Miscanthus x giganteus, Arundo donax and Phragmites australis (i.e., every specie is planted in two beds to have a replication. The influent flow rate is measured in continuous by an electronic flow meter. The effluent is evaluated by an automatic system that measure the discharged volume for each bed. Physical, chemical and microbiological analyses were carried out on wastewater samples collected at the inlet of CW plant and at the outlet of the twelve beds. An automatic weather station is installed close to the experimental plant, measuring air temperature, wind speed and direction, rainfall, global radiation, relative humidity. This allows to calculate the reference Evapotranspiration (ET0 with the Penman-Monteith formula, while the ET of different plant species is measured through the water balance of the beds. The first results show no great differences in the mean removal performances of the different plant species for TSS, COD and E.coli, ranged from, respectively, 82% to 88%, 60% to 64% and 2.7 to 3.1 Ulog. The average removal efficiency of nutrient (64% for TN; 61 for NH4-N, 31% for PO4-P in the P.australis beds was higher than that other beds. From April to November 2012 ET measured for plant species were completely different from ET0 and ETcontrol, underlining the strong effect of vegetation. The cumulative

  15. Aerobic Toluene Degraders in the Rhizosphere of a Constructed Wetland Model Show Diurnal Polyhydroxyalkanoate Metabolism. (United States)

    Lünsmann, Vanessa; Kappelmeyer, Uwe; Taubert, Anja; Nijenhuis, Ivonne; von Bergen, Martin; Heipieper, Hermann J; Müller, Jochen A; Jehmlich, Nico


    Constructed wetlands (CWs) are successfully applied for the treatment of waters contaminated with aromatic compounds. In these systems, plants provide oxygen and root exudates to the rhizosphere and thereby stimulate microbial degradation processes. Root exudation of oxygen and organic compounds depends on photosynthetic activity and thus may show day-night fluctuations. While diurnal changes in CW effluent composition have been observed, information on respective fluctuations of bacterial activity are scarce. We investigated microbial processes in a CW model system treating toluene-contaminated water which showed diurnal oscillations of oxygen concentrations using metaproteomics. Quantitative real-time PCR was applied to assess diurnal expression patterns of genes involved in aerobic and anaerobic toluene degradation. We observed stable aerobic toluene turnover by Burkholderiales during the day and night. Polyhydroxyalkanoate synthesis was upregulated in these bacteria during the day, suggesting that they additionally feed on organic root exudates while reutilizing the stored carbon compounds during the night via the glyoxylate cycle. Although mRNA copies encoding the anaerobic enzyme benzylsuccinate synthase (bssA) were relatively abundant and increased slightly at night, the corresponding protein could not be detected in the CW model system. Our study provides insights into diurnal patterns of microbial processes occurring in the rhizosphere of an aquatic ecosystem. Constructed wetlands are a well-established and cost-efficient option for the bioremediation of contaminated waters. While it is commonly accepted knowledge that the function of CWs is determined by the interplay of plants and microorganisms, the detailed molecular processes are considered a black box. Here, we used a well-characterized CW model system treating toluene-contaminated water to investigate the microbial processes influenced by diurnal plant root exudation. Our results indicated stable

  16. Evaluating the potential of 'on-line' constructed wetlands for mitigating pesticide transfers from agricultural land to surface waters (United States)

    Whelan, Michael; Ramos, Andre; Guymer, Ian; Villa, Raffaella; Jefferson, Bruce


    Pesticides make important contributions to modern agriculture but losses from land to water can present problems for environmental management, particularly in catchments where surface waters are abstracted for drinking water. Where artificial field drains represent a dominant pathway for pesticide transfers, buffer zones provide little mitigation potential. Instead, "on-line" constructed wetlands have been proposed as a potential means of reducing pesticide fluxes in drainage ditches and headwater streams. Here, we evaluate the potential of small free-surface wetlands to reduce pesticide concentrations in surface waters using a combination of field monitoring and numerical modelling. Two small constructed wetland systems in a first order catchment in Cambridgeshire, UK, were monitored over the 2014-2015 winter season. Discharge was measured at several flow control structures and samples were collected every eight hours and analysed for metaldehyde, a commonly-used molluscicide. Metaldehyde is moderately mobile and, like many other compounds, it has been regularly detected at high concentrations in surface water samples in a number of drinking water supply catchments in the UK over the past few years. However, it is unusually difficult to remove via conventional drinking water treatment which makes it particularly problematical for water companies. Metaldehyde losses from the upstream catchment were significant with peak concentrations occurring in the first storm events in early autumn, soon after application. Concentrations and loads appeared to be unaffected by transit through the wetland over a range of flow conditions - probably due to short solute residence times (quantified via several tracing experiments employing rhodamine WT - a fluorescent dye). A dynamic model, based on fugacity concepts, was constructed to describe chemical fate in the wetland system. The model was used to evaluate mitigation potential and management options under field conditions and

  17. Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype (United States)

    Nelson, M.; Alling, A.; Dempster, W. F.; van Thillo, M.; Allen, John

    Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens ™" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.

  18. Potential mining of lithium, beryllium and strontium from oilfield wastewater after enrichment in constructed wetlands and ponds. (United States)

    Schaller, Jörg; Headley, Tom; Prigent, Stephane; Breuer, Roman


    Shortages of resources (chemical elements) used by growing industrial activities require new techniques for their acquisition. A suitable technique could be the use of wetlands for the enrichment of elements from produced water of the oil industry. Oil industries produce very high amounts of water in the course of oil mining. These waters may contain high amounts of rare elements. To our best knowledge nothing is known about the economic potential regarding rare element mining from produced water. Therefore, we estimated the amount of harvestable rare elements remaining in the effluent of a constructed wetland-pond system which is being used to treat and evaporate vast quantities of produced waters. The examined wetland system is located in the desert of the south-eastern Arabian Peninsula. This system manages 95,000 m(3) per day within 350 ha of surface flow wetlands and 350 ha of evaporation ponds and is designed to be used for at least 20 years. We found a strong enrichment of some chemical elements in the water pathway of the system (e.g. lithium up to 896 μg L(-1) and beryllium up to 139 μg L(-1)). For this wetland, lithium and beryllium are the elements with the highest economic potential resulting from a high price and load. It is calculated that after 20 years retention period 131 t of lithium and 57 t of beryllium could be harvested. This technique may also be useful for acquisition of rare earth elements. Other elements (e.g. strontium) with a high calculated load of 4500 tons in 20 years are not efficiently harvestable due to a relatively low market value. In conclusion, wetland treated waters from the oil industry offer a promising new acquisition technique for elements like lithium and beryllium. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Diversity, distribution and hydrocarbon biodegradation capabilities of microbial communities in oil-contaminated cyanobacterial mats from a constructed wetland. (United States)

    Abed, Raeid M M; Al-Kharusi, Samiha; Prigent, Stephane; Headley, Tom


    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 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 communities and that these mats contribute directly to the removal of hydrocarbons from oil field wastewaters.

  20. Mathematical Model of Hybrid Precast Gravity Frames for Smart Construction and Engineering


    Seon-Chee Park; Won-Kee Hong; Sunkuk Kim; Xiangyu Wang


    The structural stability, constructability, economic feasibility, environmental-friendliness, and energy efficiency of hybrid composite frame systems have been demonstrated by practical application and research. A hybrid composite frame system combines the economy of precast concrete structures with the constructability of steel frame structures, including erection speed. Novel composite frames will ultimately maximize the efficiency of structural design and facilitate construction. This pape...

  1. Evaluation of Hybrid Learning in a Construction Engineering Context: A Mixed-Method Approach (United States)

    Karabulut-Ilgu, Aliye; Jahren, Charles


    Engineering educators call for a widespread implementation of hybrid learning to respond to rapidly changing demands of the 21st century. In response to this call, a junior-level course in the Construction Engineering program entitled Construction Equipment and Heavy Construction Methods was converted into a hybrid learning model. The overarching…

  2. Microbial population dynamics in response to bioaugmentation in a constructed wetland system under 10°C. (United States)

    Zhao, Xinyue; Yang, Jixian; Bai, Shunwen; Ma, Fang; Wang, Li


    Compound microbial inocula were enriched and applied to a pilot-scale constructed wetland system to investigate their bioaugmentation effect on nitrogen removal under cold temperature (10°C). The results showed a 10% higher removal efficiency of ammonia and total nitrogen compared to a control (unbioaugmented) group. The microbial community structures before and after the bioaugmentation were analyzed through high throughput sequencing using Miseq Illumina platform. A variation of species richness and community equitability was observed in both systems. It is demonstrated that, based on the response of both the performance and microbial community, bioaugmentation using compound microbial inocula can fine tune the bacterial population and enhance the nitrogen removal efficiency of a constructed wetland system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. French vertical flow constructed wetlands: a need of a better understanding of the role of the deposit layer. (United States)

    Molle, Pascal


    French vertical flow constructed wetlands, treating directly raw wastewater, have become the main systems implemented for communities under 2,000 population equivalent in France. Like in sludge drying reed beds, an organic deposit layer is formed over time at the top surface of the filter. This deposit layer is a key factor in the performance of the system as it impacts hydraulic, gas transfers, filtration efficiency and water retention time. The paper discusses the role of this deposit layer on the hydraulic and biological behaviour of the system. It presents results from different studies to highlight the positive role of the layer but, as well, the difficulties in modelling this organic layer. As hydraulic, oxygen transfers, and biological activity are interlinked and impacted by the deposit layer, it seems essential to focus on its role (and its quantification) to find new developments of vertical flow constructed wetlands fed with raw wastewater.

  4. Performance of Free Water Surface Constructed Wetland Using Typhalatifolia and Canna Lilies for the Treatment of Domestic Wastewater. (United States)

    Shrikhande, Avinash N; Nema, P; Mhaisalkar, Vasant A


    Discharge of untreated wastewater or partially treated wastewater into surface water bodies or on to land is a major cause of surface and ground water pollution thereby posing health hazards. Conventional wastewater treatment is generally not preferred for small communities due to higher capital and maintenance costs and lack of skilled supervision required for operation and maintenance. A constructed wetland treatment appears to be an appropriate alternative that can be employed both in developed and developing countries. A constructed wetland system is simple to construct and operate with low cost, and hence worth considering for the treatment of municipal wastewaters, especially from small communities. In this context, the site for carrying out the studies related to wastewater treatment was chosen at Kavikulguru Institute of Technology and Science (KITS), Ramtek, Dist. Nagpur. A Free Water Surface Constructed Wetland (FWSCW) of size 22.00m x 6.50 m x 0.60m was constructed at KITS, Ramtek. The performance of FWS CW system was studied for domestic wastewater treatment with theoretical hydraulic retention times of 10 days, 7 days and 5 days. Important parameters, such as BOD5, COD, TSS, NH4-N, PO4-P, DO, pH and faecal coliforms in both raw and treated wastewaters were monitored during a macrophytes life cycle. Based on the studies, it is concluded that minimum 5 days HRT is necessary for the treatment of wastewater in FWSCW using Typhalatifolia or Canna Lilies. Typhalatifolia is better in removal of pollutants from the wastewater in comparison to Canna Lilies and hence, is recommended for use in constructed wetland. The nutrient uptake capacity of Typhalatifolia is also quite encouraging and hence has great potential for application in treating wastewater from fertilizer industry. During the application of kinetic model, the observed and predicted values in respect of BOD, TSS and NH4-N in case of Typhalatifolia and BOD, COD and TSS in case of Canna Lilies were

  5. Potential of Constructed Wetlands for Removal of Antibiotics from Saline Aquaculture Effluents

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    Maria Bôto


    Full Text Available This work aimed to evaluate the potential of constructed wetlands (CWs for removal of antibiotics (enrofloxacin and oxytetracycline and antibiotic resistant bacteria from saline aquaculture wastewaters. Removal of other contaminants (nutrients, organic matter and metals and toxicity reduction and the influence of antibiotics with these processes were evaluated. Thus, nine CWs microcosms, divided into three treatments, were assembled and used to treat wastewater (doped or not with the selected antibiotics between October and December of 2015. Each week treated wastewater was removed and new wastewater (doped or not was introduced in CWs. Results showed >99% of each antibiotic was removed in CWs. After three weeks of adaptation, removal percentages >95% were also obtained for total bacteria and for antibiotic resistant bacteria. Nutrients, organic matter and metal removal percentages in CWs treated wastewater were identical in the absence and in the presence of each antibiotic. Toxicity in treated wastewaters was significantly lower than in initial wastewaters, independently of antibiotics presence. Results showed CWs have a high efficiency for removing enrofloxacin or oxytetracycline as well as antibiotic resistant bacteria from saline aquaculture wastewaters. CWs can also remove other contaminants independently of drug presence, making the aquaculture wastewater possible to be reutilized and/or recirculated.

  6. Combined Industrial Wastewater Treatment in Anaerobic Bioreactor Posttreated in Constructed Wetland

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    Bibi Saima Zeb


    Full Text Available Constructed wetland (CW with monoculture of Arundo donax L. was investigated for the posttreatment of anaerobic bioreactor (ABR treating combined industrial wastewater. Different dilutions of combined industrial wastewater (20, 40, 60, and 80 and original wastewater were fed into the ABR and then posttreated by the laboratory scale CW. The respective removal efficiencies of COD, BOD, TSS, nitrates, and ammonia were 80%, 78–82%, 91.7%, 88–92%, and 100% for original industrial wastewater treated in ABR. ABR was efficient in the removal of Ni, Pb, and Cd with removal efficiencies in the order of Cd (2.7% > Ni (79% > Pb (85%. Posttreatment of the ABR treated effluent was carried out in lab scale CW containing A. donax L. CW was effective in the removal of COD and various heavy metals present in ABR effluents. The posttreatment in CW resulted in reducing the metal concentrations to 1.95 mg/L, 0 mg/L, and 0.004 mg/L for Ni, Pb, and Cd which were within the permissible water quality standards for industrial effluents. The treatment strategy was effective and sustainable for the treatment of combined industrial wastewater.

  7. Nutrients removal by Typha latifolia and Cynodon spp. grown in constructed wetlands

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    Mateus Pimentel de Matos


    Full Text Available The objective of this study was to evaluate the extraction capacity of two species when grown in constructed wetlands with subsurface horizontal flow (SACs for the treatment of swine wastewater (ARS. To this end, were built 8 SACs of 2.0 m x 0.5 m x 0.6 m, fiber glass, filled with 0.55 m of fine gravels. In SAC2; SAC4; SAC6 and SAC8 was cultivated cattail (Typha latifolia and in SAC3; SAC5; SAC7 and SAC9 was cultivated tifton-85 bermudagrass (Cynodon spp.. The SAC2 and SAC3, SAC4 and SAC5, SAC6 and SAC7 and SAC8 and SAC9 received 163, 327, 461 and 561 kg ha-1 day-1 of BOD, respectively. During the 120 days of the SACs monitoring, it was found that the cattail has not adapted to the conditions of exposure. The highest yields were obtained with the application of organic load average of 327 kg ha-1 day-1 of BOD. The tifton-85 was the plant species with the highest capacity to extract nutrients, getting to draw between 443 and 540, 86 and 99, 193 and 241, 0.77 and 2.17, and 1.21 and 3.68 kg ha-1 TKN, P, K, Cu and Zn, respectively, while cattail showed greater capacity to absorb sodium.

  8. Experiment Research on Purifying Domestic Sewage by Duplex Subsurface Flow Constructed Wetlands

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    SHANG Ping


    Full Text Available The purification effect on domestic sewage were researched in the new-type of duplex subsurface flow constructed wetlands, of which pollutants were analyzed through the small scale test on the purification effect under different conditions of hydraulic loading, season,aeration pattern. The results showed that water quality of the system was stabilized, which could reach the 1 class A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant ( GB 18918-2002.The removal rate of COD,NH3-N could reach up to 87.2%, 68.9% under the conditions of the hydraulic load being 184 mm·d-1.And there were still more than 20% removal efficien-cy of various pollutants on the conditions of low temperature in winter. Orthogonal test showed that the optimum operating conditions was 28.6℃for the temperature, 0.184 m3·m-2·d-1 for hydraulic loading, and 2.4 d for hydraulic retention time. The experimental research showed that pre-aeration was significantly better than the anaerobic treatment on purifying effect.

  9. Multilayer Substrate Configuration Enhances Removal Efficiency of Pollutants in Constructed Wetlands

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    Shaoyuan Bai


    Full Text Available This study aimed at optimizing horizontal subsurface flow constructed wetlands (CWs to improve hydraulic performance and pollutant removal efficiency. A groundwater modeling package (MODFLOW was used to optimize three design parameters (length-to-width ratio, inlet/outlet-to-length ratio, and substrate size configuration. Using the optimized parameters, three pilot-scale CWs were built to treat actual wastewater. For model validation, we used a tracer test to evaluate hydraulic performance, and investigated the pollutant spatial distributions and removal efficiencies. We conclude that MODFLOW is suitable for designing CWs, accurately predicting that increasing hydraulic conductivity from surface to bottom layers could improve performance. However, the effect of vegetation, which decreased the hydraulic conductivity of the surface layer, should be considered to improve simulation results. Multilayer substrate configuration, with increasing hydraulic conductivity from the surface to bottom layers, significantly increased pollutant removal compared with monolayer configuration. The spatial variation in pollutant transport and degradation through the filling substrate showed that the multilayer configuration was able to increase use of the available space and moderately reduced short-circuiting and dead zones. Thus, multilayer CWs had higher experimental retention times, effective volume fractions and hydraulic efficiencies, and lower short-circuiting compared with monolayer CWs operating under similar conditions.

  10. The Potential Growth of Sugarcane in Constructed Wetlands Designed for Tertiary Treatment of Wastewater

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    Dina M. R. Mateus


    Full Text Available This research was conducted to evaluate the feasibility of using the bioenergy crop Saccharum officinarum (sugarcane as vegetation and mineral wastes for filling in constructed wetlands (CWs designed for the removal of nutrients from wastewater. Four horizontal subsurface flow pilot-scale CWs were monitored during one year: two filled with fragmented limestone and two with clay brick fragments, two planted and two unplanted controls. Sugarcane stalk height, diameter and foliar area were evaluated during the plant-cane cycle along with total phosphorus (TP and total nitrogen (TN removal efficiencies from the wastewater. Sugarcane biomass production was 107 ton/ha for the brick fragments filled CW and 67 ton/ha for the fragmented limestone filled CW. Planted CWs show better nutrient removal efficiencies than the unplanted. Planted CW filled with brick fragments show average efficiencies of 77% ± 4% for TP and 60% ± 12% for TN, and planted CW filled with fragmented limestone 68% ± 3% for TP and 58% ± 7% for TN. Results showed that the use of sugarcane as CW vegetation is a viable alternative to produce a bioethanol raw-material without the use of arable land and irrigation water, while it maintains the wastewater treatment capabilities of CWs.

  11. Treatment and utilization of septic tank effluent using vertical-flow constructed wetlands and vegetable hydroponics. (United States)

    Cui, Li-Hua; Luo, Shi-Ming; Zhu, Xi-Zhen; Liu, Ying-Hu


    Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD5, SS, TN and TP were 71.4%, 97.5%, 96.9%, 86.3%, and 87.4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%-90% and 85%-96%, respectively.

  12. Use of constructed wetland systems with Arundo and Sarcocornia for polishing high salinity tannery wastewater. (United States)

    Calheiros, Cristina S C; Quitério, Paula V B; Silva, Gabriela; Crispim, Luís F C; Brix, Hans; Moura, Sandra C; Castro, Paula M L


    Treatment of tannery wastewater is problematic due to high and variable concentrations of complex pollutants often combined with high salinity levels. Two series of horizontal subsurface flow constructed wetlands (CWs) planted with Arundo donax and Sarcocornia fruticosa were set up after a conventional biological treatment system operating at a tannery site. The aim of the CWs was polishing organics and nitrogen from the high salinity effluent (2.2-6.6 g Cl(-) L(-1)). Both plant species established and grew well in the CW. Arundo, however, had more vigorous growth and a higher capacity to take up nutrients. The CWs were efficient in removing COD and BOD(5) with removal efficiencies varying between 51 and 80% for COD (inlet: 68-425 mg L(-1)) and between 53 and 90% for BOD(5) (inlet: 16-220 mg L(-1)). Mass removal rates were up to 615 kg COD ha(-1) d(-1) and 363 BOD(5) kg ha(-1) d(-1). Removal efficiencies were 40-93% for total P, 31-89% for NH(4)(+) and 41-90% for Total Kjeldahl Nitrogen. CW systems planted with salt tolerant plant species are a promising solution for polishing saline secondary effluent from the tannery industry to levels fulfilling the discharge standards. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Removal of nitrogen and phosphorus from dairy wastewater using constructed wetlands systems operating in batch

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    Ronaldo Rocha Bastos


    Full Text Available This work presents the results of a study conducted for a period of seven months on the effectiveness of constructed wetland systems for the treatment of dairy wastewater aiming at removing, nitrogen and phosphorus. Six experimental systems were assembled with a net volume of 115 L using HDPE tanks, with length/width ratio of 2:1. In three of the systems, gravel 0 was used as substrate, while gravel 0 and sand was used in the three others, in the percentage of 80% and 20%, respectively. The systems were operated in batch cycles of 48 hours, applying 7.5 L of influent per cycle. Four of the experimental units were cultivated, and two kept as controls. The selected species chosen were the macrophytes, Typha domingensis and Hedychium coronarium. The removal efficiency concerning nitrogen compounds showed to be quite promising with values ranging from 29.4 to 73.4%, while phosphorus removal from the beds was lower, reaching efficiencies between 18.61 and 34.3%, considered good values, since the removal of these substances is quite difficult through conventional treatment.

  14. Modeling the Effect of Plants and Peat on Evapotranspiration in Constructed Wetlands

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    Florent Chazarenc


    Full Text Available Evapotranspiration (ET in constructed wetlands (CWs represents a major factor affecting hydrodynamics and treatment performances. The presence of high ET was shown to improve global treatment performances, however ET is affected by a wide range of parameters including plant development and CWs age. Our study aimed at modelling the effect of plants and peat on ET in CWs; since we hypothesized peat could behave like the presence of accumulated organic matter in old CWs. Treatment performances, hydraulic behaviour, and ET rates were measured in eight 1 m2 CWs mesocosm (1 unplanted, 1 unplanted with peat, 2 planted with Phragmites australis, 2 planted with Typha latifolia and 2 planted with Phragmites australis with peat. Two models were built using first order kinetics to simulate COD and TKN removal with ET as an input. The effect of peat was positive on ET and was related to the better growth conditions it offered to macrophytes. Removal efficiency in pilot units with larger ET was higher for TKN. On average, results show for COD a k20 value of 0.88 d-1 and 0.36 d-1 for TKN. We hypothesized that the main effect of ET was to concentrate effluent, thus enhancing degradation rates.

  15. Seasonal effects of pre-aeration on microbial processes for nitrogen removal in constructed wetlands. (United States)

    Wang, Ling; Li, Tian


    Seasonal effects of pre-aeration on microbial nitrogen performance in constructed wetlands (CWs) involved with anaerobic ammonium oxidation (anammox) process were investigated in this study. Slow natural re-aeration rate was the inhibiting factor for total nitrogen removal in CW without pre-aeration, and partial nitrification was the main way for nitrite generation. Besides partial nitrification, pre-aeration provided nitrite generation in CWs with an alternative way: nitrate reduction. Advantage of pre-aeration of influent was much different under various temperature ranges. Mean temperature of 15 °C seemed to be the turning point. With a mean temperature of or higher than 15 °C, nitrate in the influent effectively improved nitrogen removal in CWs. With a mean temperature lower than 15 °C, the nitrate reduction process in CWs was greatly inhibited. The benefit of pre-aeration was weak under this temperature range. Seasonal aeration pattern for the pre-treatment of HSSF CWs might be a more energy-saving alternative in in-suit domestic sewage treatment.

  16. Performance of Four Full-Scale Artificially Aerated Horizontal Flow Constructed Wetlands for Domestic Wastewater Treatment

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    Eleanor Butterworth


    Full Text Available A comparison of the performance of four full-scale aerated horizontal flow constructed wetlands was conducted to determine the efficacy of the technology on sites receiving high and variable ammonia loading rates not yet reported in the literature. Performance was assessed in terms of ammonia and solids removal, hydraulic conductivity and mixing patterns. The capability of systems to produce ammonium effluent concentrations <3 mgNH4+-N/L was observed across all sites in systems receiving variable loadings between 0.1 and 13.0 gNH4+-N/m2/d. Potential resilience issues were observed in relation to response to spike loadings posited to be due to an insufficient nitrifying population within the beds. Hydraulic conductivity and flow mixing patterns observed suggested deterioration of the reactor effective volume over time. Overall, the study demonstrates the efficacy of the technology where ammonium removal is required on small sites receiving high and variable flow rates, with adequate removal of organics and solids, but no significant benefit to the long term hydraulics of the system.

  17. Enhanced nitrogen removal in constructed wetlands: effects of dissolved oxygen and step-feeding. (United States)

    Li, Fengmin; Lu, Lun; Zheng, Xiang; Ngo, Huu Hao; Liang, Shuang; Guo, Wenshan; Zhang, Xiuwen


    Four horizontal subsurface flow constructed wetlands (HSFCWs), named HSFCW1 (three-stage, without step-feeding), HSFCW2 (three-stage, with step-feeding), HSFCW3 (five-stage, without step-feeding) and HSFCW4 (five-stage, with step-feeding) were designed to investigate the effects of dissolved oxygen (DO) and step-feeding on nitrogen removal. High removal of 90.9% COD, 99.1% ammonium nitrogen and 88.1% total nitrogen (TN) were obtained simultaneously in HSFCW4 compared with HSFCW1-3. The excellent TN removal of HSFCW4 was due to artificial aeration provided sufficient DO for nitrification and the favorable anoxic environment created for denitrification. Step-feeding was a crucial factor because it provided sufficient carbon source (high COD: nitrate ratio of 14.3) for the denitrification process. Microbial activities and microbial abundance in HSFCW4 was found to be influenced by DO distribution and step-feeding, and thus improve TN removal. These results suggest that artificial aeration combined with step-feeding could achieve high nitrogen removal in HSFCWs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Application of the removal of pollutants from textile industry wastewater in constructed wetlands using fuzzy logic. (United States)

    Dogdu, Gamze; Yalcuk, Arda; Postalcioglu, Seda


    There are more than a hundred textile industries in Turkey that discharge large quantities of dye-rich wastewater, resulting in water pollution. Such effluents must be treated to meet discharge limits imposed by the Water Framework Directive in Turkey. Industrial treatment facilities must be required to monitor operations, keep them cost-effective, prevent operational faults, discharge-limit infringements, and water pollution. This paper proposes the treatment of actual textile wastewater by vertical flow constructed wetland (VFCW) systems operation and monitoring effluent wastewater quality using fuzzy logic with a graphical user interface. The treatment performance of VFCW is investigated in terms of chemical oxygen demand and ammonium nitrogen (NH4-N) content, color, and pH parameters during a 75-day period of operation. A computer program was developed with a fuzzy logic system (a decision- making tool) to graphically present (via a status analysis chart) the quality of treated textile effluent in relation to the Turkish Water Pollution Control Regulation. Fuzzy logic is used in the evaluation of data obtained from the VFCW systems and for notification of critical states exceeding the discharge limits. This creates a warning chart that reports any errors encountered in a reactor during the collection of any sample to the concerned party.

  19. [Nitrogen removal under the condition of carbon source supplement in integrated vertical-flow constructed wetland]. (United States)

    She, Li-Hua; He, Feng; Xu, Dong; Lin, Ji-Dong; Wu, Zhen-Bin


    Carbon source is the main factor influencing biological denitrification efficiency. In most cities of China, carbon content in sewage was observed to be low, herein carbon source supplement should be considered to provide electron donors needed in biological denitrification process. The influence of adding different carbon sources through aeration pipe of integrated vertical-flow constructed wetland (IVCW) on nitrogen removal had been studied. Carbon source supplement to the bottom of IVCW could improve microbe conditions and intensify nitrogen removalfunction of IVCW. The results showed that glucose as external carbon source was better than carboxymethyl cellulose (CMC) on denitrification. Nitrogen removal had significant difference between adding glucose and no carbon source in IVCW system (p < 0.05). By the experiments of adding different quantity of glucose, the dose of 1.5 g glucose under 60 L x d(-1) hydraulic load was the optimization for denitrification. C6H12O6:NO3(-) -N was 4.3 and far lower than that by adding in inflow. So carbon source supplement to the bottom of IVCW through aeration pipe could save carbon source supplement cost. Additionally, adding glucose for four hours before influent feeding could improve nitrogen removal.

  20. Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands. (United States)

    Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro


    The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Decentralized domestic wastewater treatment using intermittently aerated vertical flow constructed wetlands: impact of influent strengths. (United States)

    Wu, Haiming; Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Hu, Zhen; Liang, Shuang


    In this study, the removal performances of organic pollutants and nitrogen in vertical flow constructed wetlands (VFCWs) with and without intermittent aeration fed with different strengths of influent were evaluated as a possible treatment for decentralized domestic wastewater in northern China. The intermittent aeration strategy not only significantly increased removal efficiencies of organic pollutants and ammonium nitrogen (NH4(+)-N), but also successfully created alternate aerobic and anaerobic conditions resulting in high total nitrogen (TN) removal. Moreover, increasing influent strength did not affect the removal efficiencies of organic matters and nitrogen in aerated VFCWs. Compared with non-aerated VFCWs, much higher removal of organic pollutants (96%), NH4(+)-N (98%), and TN (85%) was obtained simultaneously in intermittent aeration VFCWs, especially at high influent strengths. The results suggest that the intermittent aeration could be an appropriate strategy for achieving the high removal performance in VFCWs, especially for in-situ treatment of high strength decentralized domestic wastewaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Stormwater Treatment Evaluation of a Constructed Floating Wetland after Two Years Operation in an Urban Catchment

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    Christopher Walker