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Zhu H, Liu Y, Peng Z, Liu Q, Pan X, Yang B. Enhanced nitrogen removal by an isolated aerobic denitrifying strain in a vertical-flow constructed wetland. CHEMOSPHERE 2024; 359:142131. [PMID: 38697574 DOI: 10.1016/j.chemosphere.2024.142131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 04/10/2024] [Accepted: 04/22/2024] [Indexed: 05/05/2024]
Abstract
The addition of bacterial agents is an effective method for improving nitrogen removal from wetlands. Herein, an aerobic denitrifier, RC-15, was added to a vertical-flow constructed wetland (CW), and the presence of functional genes and microbial communities was investigated at different CW depths. For the RC-15-treated CW, the removal of NO3- and TN during the process was significantly greater than in the control. Quantitative PCR revealed that nirS is a dominant denitrifying gene for treating WWTP tailwater. Moreover, the presence of the RC-15 strain significantly enhanced the abundance of the napA gene and nirK gene in the CWs. The napA gene was concentrated in the upper layer of the CWs, and the nirK gene was concentrated in the middle and bottom layers. Compared to the control, the addition of the bacterial agent Trial resulted in a more diverse denitrification pathway, a greater abundance of 16Sr RNA, and a greater number of denitrifying strains. According to the microbial community analysis, Proteobacteria and Chloroflexi dominated denitrification in the CWs. Greater abundances of Thauera, Aeromonas and Ardenticatenales were found at the genus level, indicating that these genera have potential applications in future nitrogen removal projects.
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Affiliation(s)
- Hongxu Zhu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China; Kunming Metallurgical Research Institute Co., Ltd., Kunming, 650031, China
| | - Yanmei Liu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China; College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Zhenghua Peng
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
| | - Qiuyun Liu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
| | - Xuejun Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China.
| | - Benqin Yang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China
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2
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Li L, Zhang J, Shi Q, Lu S. Comparison of nitrogen removal performance and mechanism from low-polluted wastewater by constructed wetlands with two oxygen supply strategies: Tidal flow and intermittent aeration. CHEMOSPHERE 2023; 313:137364. [PMID: 36427582 DOI: 10.1016/j.chemosphere.2022.137364] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/01/2022] [Accepted: 11/21/2022] [Indexed: 06/16/2023]
Abstract
Due to dissolved oxygen (DO) limited nitrogen removal efficiency in constructed wetlands (CWs), two representative oxygen-suppling CWs, i.e., tidal flow constructed wetlands (TFCWs) and intermittently aerated constructed wetlands (IACWs) were proposed to compare the effect of oxygen supply strategies on the nitrogen removal performance and mechanism. Results showed that the removal efficiencies of NH4+-N and COD in IACWs were as high as 90.35-97.14% and 91.14-92.44%, respectively. In terms of TN, TFCWs (83.82%) showed a significantly higher removal efficiency than IACWs, and this result was derived with the flooded/drained phase (FP/DP) ratio of 21 h:3 h in TFCWs, because rhythmic FP and DP formed a high oxygen gradient at different depths of the system, which intensified the nitrification and denitrification simultaneously. The potential nitrifying and denitrifying bacteria (e.g., Nitrospira, Azospira, Haliangium, Bradyrhizobium and Arenimonas) were enriched more significantly in TFCWs compared with IACWs, as well as Bacillus for simultaneous nitrification and denitrification, which promoted nitrogen transformation together. Also, the results of molecular ecological network analysis showed that bacterial community structure in IACWs was more complex and robust than in TFCWs, because there were obviously more nodes and links as well as a higher proportion of negative interference. However, the relationship between genera in TFCWs was closer depending on shorter path distances, and the keystone genus (Nitrosomonas) in related to nitrification was considered to play an important role in nitrogen transformation performance.
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Affiliation(s)
- Linlin Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; College of Water Science, Beijing Normal University, Beijing, 100875, PR China
| | - Jing Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Qiuyue Shi
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Shaoyong Lu
- State Key Laboratory of Environmental Criteria and Risk Assessment, State Environmental Protection Key Laboratory for Lake Pollution Control, National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; College of Water Science, Beijing Normal University, Beijing, 100875, PR China.
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3
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Zhou M, Cao J, Lu Y, Zhu L, Li C, Wang Y, Hao L, Luo J, Ren H. The performance and mechanism of iron-modified aluminum sludge substrate tidal flow constructed wetlands for simultaneous nitrogen and phosphorus removal in the effluent of wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157569. [PMID: 35882329 DOI: 10.1016/j.scitotenv.2022.157569] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/17/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Aiming at the poor N and P removal performance in the effluent of wastewater treatment plants by constructed wetlands (CWs), aluminum sludge (AS) from water supply plants was used to prepare iron-modified aluminum sludge (IAS), and tidal flow constructed wetlands (TFCWs) using IAS as substrates were constructed. By means of high-throughput sequencing, X-ray diffractometer (XRD), etc., the removal mechanism of N and P in the system and fate analysis of key elements were also interpreted. Results showed that an interlayer structure beneficial to adsorbing pollutants was formed in the IAS, due to the iron scraps entering into the molecular layers of AS. The removal rates of TP and TN by IAS-TFCWs reached 95 % and 47 %, respectively, when the flooding/resting time (F/R) and C/N were 6 h/2 h and 6. During the three-year operation of the IAS-TFCWs, the effluent concentrations of CODCr, NH4+-N, and TP could comply with Class IV Standard of "Environmental Quality Standards for Surface Water" (GB3838-2002). The mechanism analysis showed that the N removal was effectuated through Fe2+ as the electron donor of Fe(II)-driven the autotrophic denitrifying bacteria to reduce nitrate, while the P removal mainly depended on the adsorption reaction between FeOOH in IAS and phosphate. In conclusion, the stable Fe-N cycle in the IAS-TFCWs achieved simultaneous and efficient N and P removal.
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Affiliation(s)
- Ming Zhou
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China; Henan Yongze Environmental Technology Co., LTD, Zhengzhou 451191, China
| | - Jiashun Cao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Yanhong Lu
- Henan Yongze Environmental Technology Co., LTD, Zhengzhou 451191, China
| | - Lisha Zhu
- Henan Yongze Environmental Technology Co., LTD, Zhengzhou 451191, China
| | - Chao Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
| | - Yantang Wang
- Henan Yongze Environmental Technology Co., LTD, Zhengzhou 451191, China
| | - Liangshan Hao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Jingyang Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Hongqiang Ren
- College of Environment, Nanjing University, Nanjing 210093, China
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Canet-Martí A, Grüner S, Lavrnić S, Toscano A, Streck T, Langergraber G. Comparison of simple models for total nitrogen removal from agricultural runoff in FWS wetlands. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:3301-3314. [PMID: 35704412 DOI: 10.2166/wst.2022.179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Free water surface (FWS) wetlands can be used to treat agricultural runoff, thereby reducing diffuse pollution. However, as these are highly dynamic systems, their design is still challenging. Complex models tend to require detailed information for calibration, which can only be obtained when the wetland is constructed. Hence simplified models are widely used for FWS wetlands design. The limitations of these models in full-scale FWS wetlands is that these systems often cope with stochastic events with different input concentrations. In our study, we compared different simple transport and degradation models for total nitrogen under steady- and unsteady-state conditions using information collected from a tracer experiment and data from two precipitation events from a full-scale FWS wetland. The tanks-in-series model proved to be robust for simulating solute transport, and the first-order degradation model with non-zero background concentration performed best for total nitrogen concentrations. However, the optimal background concentration changed from event to event. Thus, to use the model as a design tool, it is advisable to include an upper and lower background concentration to determine a range of wetland performance under different events. Models under steady- and unsteady-state conditions with simulated data showed good performance, demonstrating their potential for wetland design.
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Affiliation(s)
- Alba Canet-Martí
- Department of Water, Atmosphere and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, Vienna 1190, Austria E-mail:
| | - Sabrina Grüner
- Department of Water, Atmosphere and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, Vienna 1190, Austria E-mail: ; Department of Biogeophysics, University of Hohenheim, Emil-Wolff-Str. 27, Stuttgart 70599, Germany
| | - Stevo Lavrnić
- Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Viale Giuseppe Fanin 50, Bologna 40127, Italy
| | - Attilio Toscano
- Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Viale Giuseppe Fanin 50, Bologna 40127, Italy
| | - Thilo Streck
- Department of Biogeophysics, University of Hohenheim, Emil-Wolff-Str. 27, Stuttgart 70599, Germany
| | - Guenter Langergraber
- Department of Water, Atmosphere and Environment, Institute of Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, Vienna 1190, Austria E-mail:
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5
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Chaohui X, le Z, Wang Z, Zhang Y, Gao W, Wang Y, Sun X. Remove of ammoniacal nitrogen wastewater by ultrasound/Mg/Al 2O 3/O 3. CHEMOSPHERE 2022; 288:132645. [PMID: 34695483 DOI: 10.1016/j.chemosphere.2021.132645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
A large amount of ammoniacal nitrogen wastewater discharged into the water body not only causes eutrophication and black and offensive odor in water, but also increases the difficulty and cost of water treatment, and even produces toxic effects on people and organisms. In this paper, degradation of ammoniacal nitrogen wastewater by the system of ultrasound/Mg/Al2O3/ozone (US/Mg/Al2O3/O3) was carried out. The effects of different influencing factors, such as initial pH of the solution, reaction time, temperature, catalyst addition, ozone flow rate, and ultrasonic intensity, on the degradation of ammoniacal nitrogen wastewater were investigated. The optimum reaction conditions were determined. The combination of ultrasonic technology and ozone oxidation technology can enhance the mass transfer of ozone and generate a large amount of HO. Due to Mg/Al2O3 catalyst has large surface area, the number of reactive sites and reaction molecule transport channels per unit area increases, resulting in the increase of HO on the surface, thus improving the catalytic activity. The introduction of ultrasound promotes the cleavage of N-H bonds on the catalyst surface, thereby promoting the degradation of ammoniacal nitrogen in the water. Results prove that there is not only a synergistic effect between ultrasound and catalytic ozone oxidation, but a strengthening effect of ultrasound on catalytic ozone oxidation. The research carried out in this paper provides a theoretical basis for the degradation of ammoniacal nitrogen in water.
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Affiliation(s)
- Xue Chaohui
- Zhang Zhongjing College of Chinese Medicine, Nanyang Institute of Technology, Nanyang, Henan Province, 473004, China
| | - Zhang le
- School of Public Health and Management, Shandong First Medical University &Shandong Academy of Medical Sciences, Taian, Shandong Province, 271016, China.
| | - Zhenjun Wang
- College of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China
| | - Yan Zhang
- School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Wenning Gao
- School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Yujie Wang
- School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou, 466001, China
| | - Xianke Sun
- School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou, 466001, China
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Lu J, Guo Z, Kang Y, Fan J, Zhang J. Recent advances in the enhanced nitrogen removal by oxygen-increasing technology in constructed wetlands. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 205:111330. [PMID: 32977288 DOI: 10.1016/j.ecoenv.2020.111330] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Constructed wetland has attracted more and more attention for wastewater purification due to its low construction cost and convenient operation recently. However, the unique waterflooding structure of constructed wetland makes the low dissolved oxygen level, which limits the effect of nitrogen removal in the system. Therefore, it is necessary to develop the oxygen-increasing technology to overcome the drawback in constructed wetlands. In this review, the mechanism of nitrogen removal in constructed wetland is discussed and oxygen is main influence factor is concluded. In addition, oxygen-increasing technologies in recent advances which improve the nitrogen removal efficiency greatly, are emphatically introduced. Finally, some future perspectives about oxygen-increasing techniques are also put forward in order to provide reference for further research and engineering application.
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Affiliation(s)
- Jiaxing Lu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Zizhang Guo
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
| | - Yan Kang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
| | - Jinlin Fan
- Department of Science and Technology Management, Shandong University, Jinan, 250100, China
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
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7
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Wang L, Pang Q, Zhou Y, Peng F, He F, Li W, Xu B, Cui Y, Zhu X. Robust nitrate removal and bioenergy generation with elucidating functional microorganisms under carbon constraint in a novel multianode tidal constructed wetland coupled with microbial fuel cell. BIORESOURCE TECHNOLOGY 2020; 314:123744. [PMID: 32615443 DOI: 10.1016/j.biortech.2020.123744] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
This study investigated synthetic wastewater treatment under low inflow C/N ratio and characterized NO3--N-transforming and electricity-producing bacteria in a multi-anode tidal constructed wetland-microbial fuel cell (TFCW-MFC). The optimal concurrent average removal rates of NH4+-N and NO3--N were 73% and 78%, respectively, under a flood/rest/flood time of 4 h/2h/4h in "tide" mode accompanied by one recirculation. The lowest NO3--N concentration among all anodes was observed when the electrode gap was 45 cm. Similarly, the 45 cm anode exhibited selective enrichment of Variovorax and Azoarcus. Correction analysis showed that the high relative abundance of Azoarcus was crucial in enhancing NO3--N removal, and the internal resistance significantly decreased as the relative abundance of Acidovorax increased. These results suggest that NO3--N removal and bioelectricity generation can be promoted in a TFCW-MFC with limited carbon by improving the culture conditions for specific genera.
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Affiliation(s)
- Longmian Wang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China.
| | - Qingqing Pang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Ying Zhou
- College of Environment, Hohai University, Nanjing 210098, PR China
| | - Fuquan Peng
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Fei He
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Weixin Li
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, PR China
| | - Bin Xu
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Yibin Cui
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Xiang Zhu
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
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Su MH, Azwar E, Yang Y, Sonne C, Yek PNY, Liew RK, Cheng CK, Show PL, Lam SS. Simultaneous removal of toxic ammonia and lettuce cultivation in aquaponic system using microwave pyrolysis biochar. JOURNAL OF HAZARDOUS MATERIALS 2020; 396:122610. [PMID: 32298865 DOI: 10.1016/j.jhazmat.2020.122610] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 05/22/2023]
Abstract
This study examined an aquaponic approach of circulating water containing ammonia excretions from African catfish grown in an aquaculture tank for bacterial conversion into nitrates, which then acted as a nutrient substance to cultivate lettuce in hydroponic tank. We found that microwave pyrolysis biochar (450 g) having microporous (1.803 nm) and high BET surface area (419 m2/g) was suitable for use as biological carrier to grow nitrifying bacteria (63 g of biofilm mass) that treated the water quality through removing the ammonia (67%) and total suspended solids (68%), resulting in low concentration of remaining ammonia (0.42 mg/L) and total suspended solid (59.40 mg/L). It also increased the pH (6.8), converted the ammonia into nitrate (29.7 mg/L), and increased the nitrogen uptake by the lettuce (110 mg of nitrogen per plant), resulting in higher growth in lettuce (0.0562 %/day) while maintaining BOD5 level (3.94 mg/L) at acceptable level and 100% of catfish survival rate. Our results demonstrated that microwave pyrolysis biochar can be a promising solution for growing nitrifying bacteria in aquaponic system for simultaneous toxic ammonia remediation and generation of nitrate for growing vegetable in aquaculture industry.
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Affiliation(s)
- Man Huan Su
- Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China; Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia
| | - Elfina Azwar
- Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia
| | - YaFeng Yang
- Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China
| | - Christian Sonne
- Aarhus University, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000, Roskilde, Denmark
| | - Peter Nai Yuh Yek
- Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia; School of Engineering and Technology, University College of Technology Sarawak, Lot 88, Persiaran Brooke, 96000 Sibu, Sarawak, Malaysia
| | - Rock Keey Liew
- NV WESTERN PLT, No. 208B, Jalan Macalister, Georgetown, Pulau Pinang 10400, Malaysia
| | - Chin Kui Cheng
- Faculty of Chemical & Natural Resources Engineering, Lebuhraya Tun Razak, Universiti Malaysia Pahang, Gambang Kuantan, Pahang 26300, Malaysia
| | - Pau Loke Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia
| | - Su Shiung Lam
- Pyrolysis Technology Research Group, Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia; Henan Province Engineering Research Center for Biomass Value-added Products, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
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9
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Nitrogen Removal Ability and Characteristics of the Laboratory-Scale Tidal Flow Constructed Wetlands for Treating Ammonium-Nitrogen Contaminated Groundwater. WATER 2020. [DOI: 10.3390/w12051326] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Constructed wetlands (CWs) are an effective technology to remove organic compounds and nitrogen (N) from wastewaters and contaminated environmental waters. However, the feasibility of CWs for ammonium-N (NH4+-N)-contaminated groundwater treatment is unclear. In this study, zeolite-based laboratory-scale CW was operated as a tidal flow CW with a cycle consisting of 21-h flooded and 3-h rest, and used to treat NH4+-N (30 mg L−1) contaminated groundwater. In addition to NH4+-N, nitrite (NO2−-N) and nitrate (NO3−-N) were also not detected in the effluents from the tidal flow CW. The N removal constant remained high for a longer period of time compared to the continuous flow CW. The higher and more sustainable N removal of the tidal flow CW was due to the in-situ biological regeneration of zeolite NH4+-N adsorption capacity. Vegetation of common reeds in tidal flow zeolite-based CW enhanced nitrification and heterotrophic denitrification activities, and increased the functional genes of nitrification (AOB-amoA and nxrA) and denitrification (narG, nirK, nirS, and nosZ) by 2‒3 orders of magnitude, compared to CW without vegetation. The results suggest that the combination of zeolite substrate, tidal flow, and vegetation is key for the highly efficient and sustainable N removal from NH4+-N contaminated groundwater.
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Lin CJ, Chyan JM, Zhuang WX, Vega FA, Mendoza RMO, Senoro DB, Shiu RF, Liao CH, Huang DJ. Application of an innovative front aeration and internal recirculation strategy to improve the removal of pollutants in subsurface flow constructed wetlands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 256:109873. [PMID: 31822455 DOI: 10.1016/j.jenvman.2019.109873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 11/06/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
The pollutant removal performance of traditional horizontal subsurface flow (HSSF) constructed wetlands (CWs) is limited because of the dissolved oxygen (DO) supply is insufficient. The aeration of HSSF CWs usually improves their pollutant removal performance, but a high DO induces the accumulation of nitrate-nitrogen (NO3--N) and suppresses the improvement of total nitrogen (TN) removal. In this study, an integrated solution that involved in-tank front aeration and internal recirculation (FAIR) was used to improve the pollutant removal performance of HSSF CWs. Based on the experimental results, the FAIR system significantly increased the removal efficiencies of biochemical oxygen demand (BOD) from 53.8-76.0% to 82.0-91.7% and reduced the BOD concentration in the effluent to below 10 mg L-1. The removal efficiency of ammonia-nitrogen (NH3-N) increased from 15.1-78.3% to 98.5-98.6% while the removal efficiencies of the total Kjeldahl nitrogen (TKN) of the control and FAIR HSSF CWs were 18.2-77.1% and 93.5-94.3%, respectively. HSSF CWs with FAIR outperformed aerated HSSF CWs in the removal of NH3-N and TKN. The effects of two recirculation flow ratios (Rr = recirculation flow rate/influent flow rate), 14.3 and 3.0, on the improvement of pollutant removal performance were investigated. The lower Rr did not significantly affect the improvement of BOD, NH3-N, and TKN, but a higher Rr resulted in more severe accumulation of NO3--N. The removal efficiency of TN in control HSSF CWs ranged from 20.4% to 75.5%, and in the FAIR HSSF CW was 71.6% for Rr = 14.3 and 81.3% for Rr = 3.0. However, the FAIR system did not enhance the removal performance of total phosphorus, suggesting that the DO level and internal recirculation were not dominant mechanisms for the removal of phosphorous. The easy maintenance of the FAIR system made it a superior modification for improving the pollutant removal performance of HSSF CWs.
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Affiliation(s)
- Chien Jung Lin
- Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan, ROC.
| | - Jih Ming Chyan
- Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan, ROC.
| | - Wen Xue Zhuang
- Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan, ROC.
| | - Floradelle Aboga Vega
- Camarines Norte State College, Daet 4600 Camarines Norte, Philippines; Graduate School of Engineering, Adamson University, Ermita 1000, Manila, Philippines.
| | - Rose Marie O Mendoza
- Department of Environmental Science and Engineering, Adamson University, Ermita 1000, Manila, Philippines.
| | - Delia B Senoro
- Civil Engineering and Environmental Engineering, Mapua University, Manila, 1101, Philippines.
| | - Ruei Feng Shiu
- Bioengineering, University of California, Merced, CA, USA.
| | - Chih Hsiang Liao
- Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan, ROC.
| | - Da Ji Huang
- Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan, ROC.
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Samal K, Kar S, Trivedi S. Ecological floating bed (EFB) for decontamination of polluted water bodies: Design, mechanism and performance. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 251:109550. [PMID: 31539700 DOI: 10.1016/j.jenvman.2019.109550] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/29/2019] [Accepted: 09/07/2019] [Indexed: 06/10/2023]
Abstract
Worldwide water quality is degrading and most of the water bodies are now being contaminated by heavy load of pollutants from various industries. Aquatic ecosystems are also disrupted affecting various flora and fauna adversely. Water bodies dominated with aquatic plants have high yielding capacity. These plants are capable of high nutrient accumulation and creating favorable condition in rhizosphere for microbial organic degradation, which can be applied in the restoration process of polluted lakes, natural streams and wetlands, etc. Ecological Floating Bed (EFB) is designed by using aquatic plants, floating like mat on the surface of water. The plant roots hang beneath the floating mat and provide a large surface area for biofilm growth. This paper reviewed the EFB concept, structure, mechanisms and functions. Screening of suitable macrophyte species, involvement of biofilm in organic removal process and necessity of growth media have been discussed briefly. Apart from this, effect of depth, buoyancy, vegetation coverage ratio are also represented. Detail mechanisms of oxygen transfer from top to bottom of water biomass have been well analyzed. Various pollutants present in wastewater like organics, solids, nitrogen, phosphorous, heavy metals etc. and their removal mechanism have also mentioned. Again biomass needs to be harvested in regular interval, else the absorbed nutrients may re-enter to the water body. Overall, EFB is an efficient and effective wastewater treatment technology and further research is necessary for its better utilization. Finally, based on reviews, recommendations have been made for future research.
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Affiliation(s)
- Kundan Samal
- School of Civil Engineering, Kalinga Institute of Industrial Technology-Deemed to be University Bhubaneswar, 751024, Odisha, India.
| | - Soham Kar
- School of Civil Engineering, Kalinga Institute of Industrial Technology-Deemed to be University Bhubaneswar, 751024, Odisha, India
| | - Shivanshi Trivedi
- School of Civil Engineering, Kalinga Institute of Industrial Technology-Deemed to be University Bhubaneswar, 751024, Odisha, India
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12
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Zhuang LL, Yang T, Zhang J, Li X. The configuration, purification effect and mechanism of intensified constructed wetland for wastewater treatment from the aspect of nitrogen removal: A review. BIORESOURCE TECHNOLOGY 2019; 293:122086. [PMID: 31495460 DOI: 10.1016/j.biortech.2019.122086] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 05/10/2023]
Abstract
Constructed wetland (CW) for wastewater treatment has attracted increasing attention. In this review, the system configuration optimization, purification effect and general mechanisms of nitrogen removal in CW are systematically summarized and discussed. Ammonia oxidation is a crucial and primary process for total nitrogen (TN) removal in domestic or livestock wastewater treatment. Aeration, waterdrop influent and tidal operation are three main methods to strengthen the oxygen supplement and nitrification process in CW. Aeration significantly increases the ammonia removal rate (almost 100%), followed by the removal of chemical oxygen demand (COD) and TN. Solid carbon source, iron and anode material can be filled as electron donor for the denitrification process. The co-adjustment of oxygen and carbon/electron donor can form different conditions for different nitrogen removal pathways (e.g. the simultaneous nitrification-denitrification, the partial nitrification-denitrification and the anammox process), and achieve the optimal removal of nitrogen.
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Affiliation(s)
- Lin-Lan Zhuang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China
| | - Ting Yang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China.
| | - Xiangzheng Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China
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13
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Performance of an On-Site Wastewater Treatment System Using Reactive Filter Media and a Sequencing Batch Constructed Wetland. SUSTAINABILITY 2019. [DOI: 10.3390/su11113172] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many on-site wastewater treatment systems, such as soil treatment systems, are not sustainable in terms of purification efficiency, nutrient recycling potential, and economics. In this case study, a sequencing batch constructed wetland (SBCW) was designed and added after a package treatment plant (PTP) using reactive filter media for phosphorus (P) removal and recycling. The treatment performance of the entire system in the start-up phase and its possible applicability in rural areas were investigated. Raw and treated effluents were sampled during a period of 25 weeks and analyzed for nitrogen, phosphorus, BOD7, and bacteria. Field measurements were made of wastewater flow, electrical conductivity, oxygen, and temperature. The entire system removed total-P and total inorganic nitrogen (TIN) by 83% and 22%, respectively. High salt concentration and very low wastewater temperature were possible reasons for these unexpectedly low P and TIN removal efficiencies. In contrast, removal rates of bacteria (Escherichia coli, enterococci) and organic matter (as BOD) were high, due to filtration in the alkaline medium Polonite® (Ecofiltration Nordic AB, Stockholm, Sweden) and the fine sand used as SBCW substrate. High pH in effluent from the PTP was efficiently reduced to below pH 9 in the SBCW, meeting recommendations by environmental authorities in Sweden. We concluded that treating cold on-site wastewater can impair treatment performance and that technical measures are needed to improve SBCW performance.
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Huang J, Cao C, Liu J, Yan C, Xiao J. The response of nitrogen removal and related bacteria within constructed wetlands after long-term treating wastewater containing environmental concentrations of silver nanoparticles. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 667:522-531. [PMID: 30833250 DOI: 10.1016/j.scitotenv.2019.02.396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/21/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
The wide application of consumer products containing silver nanoparticles (AgNPs) inevitably results in their release into sewer systems and wastewater treatment plants, where they would encounter (and cause potential negative impacts) constructed wetlands (CWs), a complex biological system containing plants, substrate and microorganisms. Herein, the long-term effects of environmental AgNPs concentrations on nitrogen removal, key enzymatic activities and nitrogen-related microbes in constructed wetlands (CWs) were investigated. The short-term exposure (40 d) to AgNPs significantly inhibited TN and NH4+-N removal, and the inhibition degree had a positive relationship with AgNPs levels. After about 450 d exposure, 200 μg/L AgNPs could slightly increase average TN removal efficiency, while presence of 50 μg/L AgNPs showed no difference, compared to control. The NH4+-N removal in all CWs had no difference. The present study indicated that short-term AgNPs loading evidently reduced nitrogen removal, whereas long-term exposure to AgNPs showed no adverse impacts on NH4+-N removal and slightly stimulated TN removal, which was related to the increase of corresponding enzymatic activities. After exposing AgNPs for 450 d, the abundance of relative functional genes and the composition of key community structure were determined by qPCR and high-throughput sequencing, respectively. The results showed that the abundance of amoA and nxrA dramatically higher than control, whereas the abundance of nirK, nirS, nosZ and anammox 16S rRNA was slightly higher than control, but had no statistical difference, which accorded with the TN removal performance. The microbial community analysis showed that different AgNPs concentrations could affect the microbial diversity and structure. The changes of the relative abundance of nitrogen-related genera were associated with the impacts of AgNPs on the nitrogen removal performance. Overall, the AgNPs loading had impacts on the key enzymatic activities, the abundance of nitrogen-related genes and microbial community, thus finally affected the treatment performance of CWs.
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Affiliation(s)
- Juan Huang
- Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China.
| | - Chong Cao
- Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China
| | - Jialiang Liu
- Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China
| | - Chunni Yan
- Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China
| | - Jun Xiao
- Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China
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15
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Haddaji D, Ghrabi-Gammar Z, Hamed KB, Bousselmi L. A re-circulating horizontal flow constructed wetland for the treatment of synthetic azo dye at high concentrations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:13489-13501. [PMID: 30911962 DOI: 10.1007/s11356-019-04704-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
A re-circulating horizontal flow constructed wetland (RHFCW) system was developed in a greenhouse. This system was operated with Typha domingensis to study the phytoremediation capacity of this macrophyte species in different developing stages for synthetic textile wastewater with the pollutant type, the amaranth (AM) azo dye. Experiments were applied with a fixed flow rate Q = 10 L/h corresponding to a theoretical residence time of 3 h. The synthetic feeding to the RHFCW container was re-circulated back until the required water quality was achieved. The performance of this pilot-scale system was compared to an unplanted RHFCW. The effect of the initial dye concentration was studied using four dye concentrations (10, 15, 20, and 25 mg/L). The following parameters pH, color, COD, BOD5, NO3-, NO2-, and NH4+ were monitored during treatment. The maximum efficiencies obtained for discoloration, COD, NO3-, and NH4+ were 92 ± 0.14%, 56 ± 1.12%, 92 ± 0.34%, and 97 ± 0.17% respectively. Experiences demonstrate a decrease of removal efficiencies of studied parameters with the increase of dye concentrations, leading to an increase of the duration of treatment. Changes in activities of antioxidant enzymes (superoxide dismutase (SOD), guaiacol peroxidase (GPX), catalase (CAT), ascorbic peroxidase (APX), and glutathione reductase (GR)) and their relation to plant defense system against stress were studied. Enzymes were evaluated in leaves of T. domingensis during the remediation of the azo dye (amaranth). During treatment, an increase of enzymes activities was observed in accordance with the high removal efficiency.
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Affiliation(s)
- Dalila Haddaji
- Laboratory of Wastewater and Environment, Centre for Water Researches and Technologies CERTE, B.P. 273, 8020, Soliman, Tunisia
| | - Zeineb Ghrabi-Gammar
- National Institute of Agronomy of Tunisia, University of Carthage, 43, Avenue Charles Nicolle, Cite Mahrajene, 1082, Tunis, Tunisia
| | - Karim Ben Hamed
- Laboratory of extremophiles plants, Centre of Biotechnology of Borj Cédria (CBBC), 8020, Soliman, Tunisia
| | - Latifa Bousselmi
- Laboratory of Wastewater and Environment, Centre for Water Researches and Technologies CERTE, B.P. 273, 8020, Soliman, Tunisia.
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16
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Liu Y, Liu X, Li K, Lu S, Guo X, Zhang J, Xi B. Removal of nitrogen from low pollution water by long-term operation of an integrated vertical-flow constructed wetland: Performance and mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 652:977-988. [PMID: 30380502 DOI: 10.1016/j.scitotenv.2018.10.313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/07/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
The efficiency of nitrogen removal and its mechanism, aquatic organism distribution characteristics and regeneration capability of zeolite from an integrated vertical-flow constructed wetland (IVFCW) for low pollution water treatment were evaluated after steady and continuous operation for eight years. After running for eight years, better than average COD and NH4+-N removal were observed in the IVFCW. The NH4+-N removal rate in this system was controlled by ammoxidation and adsorption and ion exchange of zeolite. The low total nitrogen (TN) removal efficiency was due to NO3--N accumulation and zeolite desorption. In addition, this phenomenon indicated that because of poor organic carbon sources, nitrification was stronger than denitrification, consistent with the distribution of the functional genes for nitrification and denitrification. The biological activity in this system was abundant, especially that of spirogyra and navicula. The saturated adsorption capacity of zeolite was as high as 1.35 mg g-1 with a desorption rate of <20%. There were no obvious differences among the effects of aeration, water cleaning, drained reoxygenation and steam stripping for zeolite regeneration (adsorption capacity of >50%). However, the drained reoxygenation performance of was better due to zero energy consumption and regeneration in situ.
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Affiliation(s)
- Ying Liu
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China
| | - Xiaohui Liu
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China; School of Environment, Tsinghua University, Beijing 100084, People's Republic of China
| | - Ke Li
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China; School of Environment, Beijing Normal University, Beijing 100088, People's Republic of China
| | - Shaoyong Lu
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China.
| | - Xiaochun Guo
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China
| | - Jian Zhang
- School of Environmental Science & Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Beidou Xi
- State Environmental Protection Scientific Observation and Research Station for Lake Dongtinghu (SEPSORSLD), National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Key Laboratory of Environmental Criteria an Risk Assessment, Research Centre of Lake Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, People's Republic of China
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17
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Di Luca GA, Mufarrege MM, Hadad HR, Maine MA. Nitrogen and phosphorus removal and Typha domingensis tolerance in a floating treatment wetland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:233-240. [PMID: 30196224 DOI: 10.1016/j.scitotenv.2018.09.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 08/15/2018] [Accepted: 09/03/2018] [Indexed: 06/08/2023]
Abstract
The aim of this work was to study the efficiency of microcosms-scale floating treatment wetlands (FTWs) in the N and P removal from a synthetic runoff effluent and to evaluate the effluent tolerance of Typha domingensis. Each FTW consisted of a raft constructed with a plastic net where T. domingensis plants were installed. In order to evaluate the plant role, reactors with FTWs and without FTWs (controls) were used. P and N additions were carried out as follows: 5 mg L-1 P (P5 and P5-control); 10 mg L-1 N (N10 and N10-control); 5 mg L-1 P + 10 mg L-1 N (P5N10 and P5N10-control). Also, a biological control (B-control) without contaminant addition was used. The removal of soluble reactive phosphorus and total phosphorus were significantly higher in the FTWs than in the controls. Ammonium and nitrate concentrations were not significantly different between FTWs and controls at the end of the experiment. However, nitrate concentrations showed significant differences between FTWs and controls during the experiment. N and P were mainly accumulated in plant tissues and not in the sediment. Plants tolerated the effluent conditions and showed a positive growth rate. The use of FTWs is a promising strategy for the sustainable treatment of water bodies affected by runoff waters.
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Affiliation(s)
- G A Di Luca
- Química Analítica, Instituto de Química Aplicada del Litoral (IQAL), Facultad de Ingeniería Química, Universidad Nacional del Litoral (UNL)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santiago del Estero 2829, Santa Fe 3000, Argentina
| | - M M Mufarrege
- Química Analítica, Instituto de Química Aplicada del Litoral (IQAL), Facultad de Ingeniería Química, Universidad Nacional del Litoral (UNL)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santiago del Estero 2829, Santa Fe 3000, Argentina.
| | - H R Hadad
- Química Analítica, Instituto de Química Aplicada del Litoral (IQAL), Facultad de Ingeniería Química, Universidad Nacional del Litoral (UNL)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santiago del Estero 2829, Santa Fe 3000, Argentina
| | - M A Maine
- Química Analítica, Instituto de Química Aplicada del Litoral (IQAL), Facultad de Ingeniería Química, Universidad Nacional del Litoral (UNL)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Santiago del Estero 2829, Santa Fe 3000, Argentina
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18
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Hua G, Shao C, Cheng Y, Kong J, Zhao Z. Parameter-efficient bioclogging model: calibration and comparison with laboratory data. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:3731-3740. [PMID: 30539400 DOI: 10.1007/s11356-018-3894-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
A parameter-efficient bioclogging model coupled with hydrodynamics was developed with a stepwise numerical calculation. Column lab tests were carried out to calibrate and verify the bioclogging model developed in this paper. The results showed that the experimental data fit well with the simulation data, which indicated that the developed model was reasonable. According to the sensitivity analysis of the parameters, the BOD (biochemical oxygen demand) loading rate and deposition coefficient are the key parameters for bioclogging. The results illustrate how the clogging is impacted by changing the BOD loading rate and can predict the biofilm accumulation within the substrate, the microbial saturation along the substrate profile over time, and the biofilter longevity based on the biomass growth. The model could dynamically describe the entire process of biological clogging and could quantitatively predict the amount of biofilm accumulated in the pores with the increasing operation time, which provides a basis for the prediction of biological clogging. Graphical abstract.
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Affiliation(s)
- Guofen Hua
- College of Water Conservancy and Hydroelectric Power, Hohai University, Nanjing, 210098, People's Republic of China.
| | - Chenfei Shao
- College of Water Conservancy and Hydroelectric Power, Hohai University, Nanjing, 210098, People's Republic of China
| | - Ying Cheng
- College of Water Conservancy and Hydroelectric Power, Hohai University, Nanjing, 210098, People's Republic of China
| | - Jun Kong
- College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing, 210098, People's Republic of China
| | - Zhongwei Zhao
- College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing, 210098, People's Republic of China
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19
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Luyao CEN, Ying CHEN, Jin ZHANG, Min LIU, Qingming WU. Pilot-scale study on advanced treatment of tail water of urban sewage treatment plant by constructed wetlands with different plants. ACTA ACUST UNITED AC 2019. [DOI: 10.18307/2019.0206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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20
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Al-Saedi R, Smettem K, Siddique KHM. Nitrogen removal efficiencies and pathways from unsaturated and saturated zones in a laboratory-scale vertical flow constructed wetland. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 228:466-474. [PMID: 30245271 DOI: 10.1016/j.jenvman.2018.09.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/08/2018] [Accepted: 09/13/2018] [Indexed: 06/08/2023]
Abstract
A laboratory-scale vertical flow constructed wetland system was designed and monitored to compare nitrogen removal rates and pathways from both saturated and unsaturated zones under a hydraulic loading rate and influent total nitrogen concentration of 1.5 m3/m2.d and 508 mg/L respectively. Weekly measurements of the concentrations of nitrogen compounds, chemical oxygen demand, temperature, dissolved oxygen, oxidation-reduction potential, and hydrogen ion concentration were taken throughout the study. At the end of the experiments, PCR analysis of 16S rRNA gene sequencing was performed to identify microbial communities in the unsaturated and saturated parts of the system. The nitrogen compounds were removed from the system after 182 days, with similar total nitrogen removal efficiencies (94% and 93%) for the unsaturated and saturated zones respectively. Heterotrophic nitrification/aerobic denitrification was the major pathway responsible for the removal of nitrogen compounds. Adsorption into the gravel bed also contributed to ammonium removal. Proteobacteria were the dominant bacterial strains involved in nitrogen transformation and accounted for 80% of the total bacteria in the unsaturated zone and 60% in the saturated zone. With little difference in the concentration removal efficiencies of the unsaturated and saturated zones, a more effective design would be an entirely saturated wetland as the total mass removal of nitrogen depends on the water volume stored, which at full saturation in this design was seven times greater per unit wetland volume than the unsaturated zone.
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Affiliation(s)
- Rasha Al-Saedi
- School of Civil, Environmental, and Mining Engineering, The University of Western Australia, Perth, WA 6001, Australia; Department of Environmental Engineering, Al- Mustansiriya University, Baghdad, Iraq; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia.
| | - Keith Smettem
- School of Civil, Environmental, and Mining Engineering, The University of Western Australia, Perth, WA 6001, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
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21
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Sánchez-Galván G, Bolaños-Santiago Y. Phytofiltration of anaerobically digested sugarcane ethanol stillage using a macrophyte with high potential for biofuel production. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2018; 20:805-812. [PMID: 29775098 DOI: 10.1080/15226514.2018.1438350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Anaerobically digested stillage (ADS) requires treatment before being discharged into water bodies or soils to avoid adverse effects. Phytofiltration systems are eco-friendly technologies for wastewater treatment, and they simultaneously serve as a source of biomass for biofuel production. The aim of the present study was to investigate the phytofiltration of ADS using Azolla sp. The effects of the ADS strength (dilutions 1: 50 and 1 : 25 v/v) and initial biomass density (IBD) [15.44 (IBD1) and 23.16 (IBD2) g dry weight (dw) m-2] on plant growth and pollutant removal were assessed. Productivities obtained at ADS 1: 50 (2.93 and 3.04 g m-2 d-1 for IBD1 and IBD2, respectively) were not significantly different from those of a synthetic medium (2.56 and 3.15 g m-2 for IBD1 and IBD2, respectively). Higher organic matter removal was found using ADS at 1: 25 than that obtained using ADS 1: 50 (52.16-53.34 vs 32.29-38.16%), while no IBD effect was observed. The nutrient concentrations in ADS were reduced significantly, especially the concentrations of NH4-N (75.11-82.54%), PO4-P (88.72-92.90%) and SO4-S (55.95-66.61%). The conversion of nutrients from ADS into Azolla biomass may result in an effective way to produce an attractive feedstock for biofuel production.
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Affiliation(s)
- Gloria Sánchez-Galván
- a Biotechnological Management of Resources Network, Institute of Ecology , Xalapa , Veracruz , México
| | - Yanet Bolaños-Santiago
- a Biotechnological Management of Resources Network, Institute of Ecology , Xalapa , Veracruz , México
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22
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Using a Backpropagation Artificial Neural Network to Predict Nutrient Removal in Tidal Flow Constructed Wetlands. WATER 2018. [DOI: 10.3390/w10010083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Liu M, Li B, Xue Y, Wang H, Yang K. Constructed wetland using corncob charcoal substrate: pollutants removal and intensification. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 76:1300-1307. [PMID: 28953456 DOI: 10.2166/wst.2017.305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
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.
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Affiliation(s)
- Mao Liu
- School of Civil Engineering, Wuhan University, Wuhan 430072, China E-mail:
| | - Boyuan Li
- School of Civil Engineering, Wuhan University of Technology, Wuhan 430070, China
| | - Yingwen Xue
- School of Civil Engineering, Wuhan University, Wuhan 430072, China E-mail:
| | - Hongyu Wang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China E-mail:
| | - Kai Yang
- School of Civil Engineering, Wuhan University, Wuhan 430072, China E-mail:
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24
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Kizito S, Lv T, Wu S, Ajmal Z, Luo H, Dong R. Treatment of anaerobic digested effluent in biochar-packed vertical flow constructed wetland columns: Role of media and tidal operation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 592:197-205. [PMID: 28319707 DOI: 10.1016/j.scitotenv.2017.03.125] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/12/2017] [Accepted: 03/12/2017] [Indexed: 05/22/2023]
Abstract
Three types of vertical flow constructed wetland columns (VFCWs), packed with corn cob biochar (CB-CW), wood biochar (WB-CW) and gravel (G-CW) under tidal flow operations, were comparatively evaluated to investigate anaerobic digested effluent treatment performance and mechanisms. It was demonstrated that CB-CW and WB-CW provide significantly higher removal efficiencies for organic matter (>59%), NH4+-N (>76%), TN (>37%) and phosphorus (>71%), compared with G-CW (22%-49%). The higher pollutants removal ability of biochar-packed VFCWs was mainly attribute to the higher adsorption ability and microbial cultivation in the porous biochar media. Moreover, increasing the flooded/drained ratio from 4/8h to 8/4h of the tidal operation further improved around 10% of the removal of both organics and NH4+-N for biochar-packed VFCWs. The phosphorus removal was dependent on the media adsorption capacities through the whole experiment. However, the NH4+-N biodegradation by microbial communities was demonstrated to become the dominant removal mechanism in the long term treatment, which compensated the decreased adsorption capacities of the media. The study supported that the use of biochar would increase the treatment performance and elongate the lifespan of CWs under tidal operation.
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Affiliation(s)
- Simon Kizito
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China; College of Agriculture and Environmental Sciences, Makerere University, 7062 Kampala, Uganda
| | - Tao Lv
- Department of Bioscience, Aarhus University, Aarhus 8000C, Denmark
| | - Shubiao Wu
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China.
| | - Zeeshan Ajmal
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China
| | - Hongzhen Luo
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China
| | - Renjie Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China
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Ilyas H, Masih I. The performance of the intensified constructed wetlands for organic matter and nitrogen removal: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 198:372-383. [PMID: 28494426 DOI: 10.1016/j.jenvman.2017.04.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/23/2017] [Accepted: 04/30/2017] [Indexed: 06/07/2023]
Abstract
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.
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Affiliation(s)
- Huma Ilyas
- Independent Researcher, Kievitlaan 9, 2289ED, Rijswijk, The Netherlands.
| | - Ilyas Masih
- IHE Delft, Institute for Water Education, Westvest 7, 2611AX, Delft, The Netherlands
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Mohammed A, Babatunde A. Modelling heavy metals transformation in vertical flow constructed wetlands. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.03.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Liu J, Zuo W, Zhang J, Li H, Li L, Tian Y. Shifts in microbial community structure and diversity in a MBR combined with worm reactors treating synthetic wastewater. J Environ Sci (China) 2017; 54:246-255. [PMID: 28391936 DOI: 10.1016/j.jes.2016.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/15/2016] [Accepted: 03/18/2016] [Indexed: 06/07/2023]
Abstract
The chemical oxygen demand (COD) and NH3-N removal, membrane fouling, sludge characteristics and microbial community structure in a membrane bioreactor (MBR) coupled with worm reactors (SSBWR) were evaluated for 210days. The obtained results were compared to those from a conventional MBR (C-MBR) operated in parallel. The results indicated that the combined MBR (S-MBR) achieved higher COD and NH3-N removal efficiency, slower increase in membrane fouling, better sludge settleability and higher activities of the related enzymes in the activated sludge. Denaturing gradient gel electrophoresis was used to analyze the microbial community structures in the C-MBR and the S-MBR. The microbial community structure in the S-MBR was more diverse than that in the C-MBR. Additionally, the slow-growing microbes such as Saprospiraceae, Actinomyces, Frankia, Clostridium, Comamonas, Pseudomonas, Dechloromonas and Flavobacterium were enriched in the S-MBR, further accounting for the sludge reduction, membrane fouling alleviation and wastewater treatment.
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Affiliation(s)
- Jia Liu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
| | - Wei Zuo
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
| | - Jun Zhang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China
| | - Hui Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China
| | - Lipin Li
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China
| | - Yu Tian
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
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Guo L, Lv T, He K, Wu S, Dong X, Dong R. Removal of organic matter, nitrogen and faecal indicators from diluted anaerobically digested slurry using tidal flow constructed wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:5486-5496. [PMID: 28028703 DOI: 10.1007/s11356-016-8297-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
The rapid implementation of anaerobic digestion for renewable energy production has resulted in increased generation of anaerobically digested slurry, which contains a variety of pollutants and therefore has the potential to cause serious environmental problems. Tidal flow constructed wetlands, which could generate beneficial oxygen conditions, were investigated for their success in removing nitrogen, organic matter and pathogens in anaerobically digested slurry. The results indicated that tidal operation had a positive effect on promoting NH4+-N and organic matter (chemical oxygen demand (COD)) removal. With an average influent NH4+-N concentration of 288 mg/L and COD concentration of 839 mg/L, the average removal efficiency reached up to 93% (325 g/m2 day) for NH4+-N and 53% (603 g/m2 day) for COD, with total inorganic nitrogen (TIN) removal efficiency of 51% (226 g/m2 day). The nitrogen removal in the tidal-operated CWs is highly dependent on the flooded and drained (F/D) time ratio. Changing flooded time from 3 to 5 h enhanced denitrification (nitrite reductase-K (nirK) abundance) and further resulted in improved TIN removal efficiency of 62% (237 g/m2 day). The removal of faecal indicators was also examined, with reduction rate of approximately 0.9 log10 CFU/100 mL for both Escherichia coli and total coliforms, which was independent of the influent loadings and differing flooded/drained time ratio. Tidal flow CWs were demonstrated to have the high potential to treat diluted anaerobically digested slurry.
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Affiliation(s)
- Luchen Guo
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083, Beijing, People's Republic of China
| | - Tao Lv
- Department of Bioscience, Aarhus University, 8000C, Aarhus, Denmark
| | - Keli He
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083, Beijing, People's Republic of China
| | - Shubiao Wu
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083, Beijing, People's Republic of China.
| | - Xinlong Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083, Beijing, People's Republic of China
| | - Renjie Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy, Ministry of Agriculture, College of Engineering, China Agricultural University, 100083, Beijing, People's Republic of China
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Chen Z, Vymazal J, Kuschk P. Effects of tidal operation on pilot-scale horizontal subsurface flow constructed wetland treating sulfate rich wastewater contaminated by chlorinated hydrocarbons. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:1042-1050. [PMID: 27770325 DOI: 10.1007/s11356-016-7871-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
Three different flow regimes were carried out in a pilot-scale horizontal subsurface flow constructed wetland-treating sulfate rich wastewater contaminated with monochlorobenzene (MCB) and perchloroethene (PCE). The three regimes were continuous flow, 7-day cycle discontinuous flow, and 2.5-day cycle discontinuous flow. The results show that intensifying the tidal regime (2.5-day cycle) significantly enhanced MCB removal before 2 m from the inlet and increasing PCE removal efficiency at 0.5 m. The PCE dechlorination process was promoted with tidal operation, especially under the 2.5-day cycle regime, with significant increases of cis-1,2- dichloroethenes (DCEs), vinyl chloride (VC), and ethene, but trans-1,2-DCE was significantly decreased after tidal operation. Due to the high sulfate concentration in the influent, sulfide was observed in pore water up to 20 and 23 mg L-1 under continuous flow and 7-day cycle regime, respectively. However, sulfide concentrations decreased to less than 4 mg L-1 under intensified tidal operation (2.5-day cycle). The increase of oxygen concentration in pore water through intensified tidal operation resulted in better MCB removal performance and the successful inhibition of sulfate reduction. In conclusion, intensifying tidal operation is an effective approach for the treatment of chlorinated hydrocarbons and inhibiting sulfide accumulation in horizontal subsurface flow constructed wetland.
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Affiliation(s)
- Zhongbing Chen
- College of Resources and Environment, Huazhong Agricultural University, Shizishan 1, Wuhan, 430070, China.
- Department of Applied Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16521, Prague, Czech Republic.
| | - Jan Vymazal
- Department of Applied Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16521, Prague, Czech Republic
| | - Peter Kuschk
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
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Pang Y, Zhang Y, Yan X, Ji G. Cold Temperature Effects on Long-Term Nitrogen Transformation Pathway in a Tidal Flow Constructed Wetland. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:13550-13557. [PMID: 26460580 DOI: 10.1021/acs.est.5b04002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
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.
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Affiliation(s)
- Yunmeng Pang
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University , Beijing 100871, China
| | - Yan Zhang
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University , Beijing 100871, China
| | - Xingjun Yan
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University , Beijing 100871, China
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University , Beijing 100871, China
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Wang Y, Wu Y, Wu Z, Tam NFY. Genotypic responses of bacterial community structure to a mixture of wastewater-borne PAHs and PBDEs in constructed mangrove microcosms. JOURNAL OF HAZARDOUS MATERIALS 2015; 298:91-101. [PMID: 26005923 DOI: 10.1016/j.jhazmat.2015.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 05/01/2015] [Accepted: 05/02/2015] [Indexed: 06/04/2023]
Abstract
Mangrove microcosms capable of removing polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) from wastewater were established under everyday tidal and non-tidal flooding regimes, along with two different mangrove species. Defining how bacterial communities change with pollutants or across treatments will contribute to understanding the microbial ecology of in situ bioremediation systems. A semi-nested PCR-DGGE (denaturing gradient gel electrophoresis) approach was employed, with known genus/species-specific primers targeting the 16S rRNA genes of Sphingomonas and Mycobacterium (related to PAH degradation) and Dehalococcoides (related to PBDE degradation). Results showed that the composition of Mycobacterium- and Dehalococcoides-like populations was critically determined by tidal regime during a medium-term (4-8 months) exposure, while that of Sphingomonas-like population, along with total bacterial community, was more dependent on sediment layer and became prominently affected by tidal regime till the end of 8-month treatment. The effect of plant species was relatively small. Canonical correspondence analysis (CCA) further revealed that Sphingomonas- and Mycobacterium-like populations were significantly associated with phenanthrene and benzo(a)pyrene, respectively, while Dehalococcoides-like population was the only group significantly related to the highest PBDE congener (BDE-209) in the mangrove microcosms.
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Affiliation(s)
- Yafen Wang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430074, China
| | - Yan Wu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Zhenbin Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Nora Fung-Yee Tam
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
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Li X, Zhang M, Liu F, Li Y, He Y, Zhang S, Wu J. Abundance and distribution of microorganisms involved in denitrification in sediments of a Myriophyllum elatinoides purification system for treating swine wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:17906-17916. [PMID: 26165997 DOI: 10.1007/s11356-015-5041-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/05/2015] [Indexed: 06/04/2023]
Abstract
Environmental pollution from livestock production, particularly swine production, is often managed by the use of constructed wetlands, which incorporate plants such as Myriophyllum elatinoides as a means of treating wastewater. The M. elatinoides purification system has been shown to effectively remove, via nitrification and denitrification, more than 90% of the total nitrogen (TN) and 84% of the NH4 (+)-N produced in swine wastewater. However, the mechanisms of variation in aquatic environmental factors and how the interaction of these factors affects denitrification by microorganisms in sediments remain poorly understood. In this study, the impacts of dissolved oxygen (DO), TN, NH4(+)-N, and NO3(-)-N on the abundance, diversity, and community distribution of denitrifiers in the sediments from different concentrations and types of wastewater including tap water (CK), two strengths of synthetic wastewater: 200 mg NH4(+)-N L(-1) (T1) and 400 mg NH4(+)-N L(-1) (T2), swine wastewater diluted 50% (T3), and swine wastewater (T4) were investigated in a microcosm experiment. A significant improvement was observed in the abundance of denitrification genes (nirK and nirS) in response to increased NO3(-)-N and DO in the swine wastewater sediments. The abundance of these denitrification genes was highest in the T4 sediments compared with other treatments. Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the DO, TN, and NH4(+)-N positively impacted the richness index (S) of the nirK denitrifiers in T1, whereas the NO3(-)-N negatively affected the Simpson diversity index (D) of nirK and nirS denitrifiers in T3 and T4. However, the NO3(-)-N positively affected the nirK and nirS denitrifier community distribution, whereas the DO negatively affected the nirK and nirS denitrifier distribution in T3 and T4. These findings will be helpful in that they allow us to recognize the effects of environmental factors on the formation of the denitrifiers in the sediments in a M. elatinoides purification system.
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Affiliation(s)
- Xi Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
| | - Miaomiao Zhang
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
| | - Feng Liu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
| | - Yong Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
| | - Yang He
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Graduate University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China
| | - Shunan Zhang
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China
- Graduate University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China
| | - Jinshui Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
- Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
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Sewage Treatment with a Hybrid Constructed Soil Filter. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2015. [DOI: 10.1515/ijcre-2015-0008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The overall aim of this research was to apply a hybrid constructed soil filter for sewage treatment. A hybrid constructed soil filter is an ecological process used for decentralized sewage treatment in villages, small towns or scattered residential areas. Sewage is firstly treated by conventional physicochemical or biological treatment and then allowed to infiltrate through aerated unsaturated zone wherein it gets purified through processes such as filtration, adsorption, chemical reaction and biodegradation. This system has demonstrated a consistent capacity to remove organic matter and nitrogen. Experimental results have shown that under hydraulic load rates of 0.22 m3/m2 · h and organic load rates ranging from 47 to 156 g COD/m2 · h, mean removal efficiencies of 89% for COD, 99% for BOD5, 86% for suspended solids and 52% for total nitrogen can be achieved using an hybrid constructed soil filter. Compared to the conventional activated sludge process, this technology has many advantages, such as simple construction, low operation and maintenance costs, as well as a simple operation.
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Kumar JLG, Zhao YQ, Hu YS, Babatunde AO, Zhao XH. Nitrogen dynamics model for a pilot field-scale novel dewatered alum sludge cake-based constructed wetland system. ENVIRONMENTAL TECHNOLOGY 2015; 36:732-741. [PMID: 25179044 DOI: 10.1080/09593330.2014.960476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A model simulating the effluent nitrogen (N) concentration of treated animal farm wastewater in a pilot on-site constructed wetland (CW) system, using dewatered alum sludge cake (DASC) as wetland substrate, is presented. The N-model was developed based on the Structural Thinking Experiential Learning Laboratory with Animation software and is considering organic nitrogen, ammonia nitrogen (NH3) and nitrate nitrogen (NO3-N) as the major forms of nitrogen involved in the transformation chains. Ammonification (AMM), ammonia volatilization, nitrification (NIT), denitrification, plant uptake, plant decaying and uptake of inorganic nitrogen by algae and bacteria were considered in this model. pH, dissolved oxygen, temperature, precipitation, solar radiation and nitrogen concentrations were considered as forcing functions in the model. The model was calibrated by observed data with a reasonable agreement prior to its applications. The simulated effluent detritus nitrogen, NH4-N, NO3-N and TN had a considerably good agreement with the observed results. The mass balance analysis shows that NIT accounts for 65.60%, adsorption (ad) (11.90%), AMM (8.90%) followed by NH4-N (Plants) (5.90%) and NO3-N (Plants) (4.40%). The TN removal was found 52% of the total influent TN in the CW. This study suggested an improved overall performance of a DASC-based CW and efficient N removal from wastewater.
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Affiliation(s)
- J L G Kumar
- a UCD Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering , University College Dublin , Newstead, Belfield, Dublin 4 , Ireland
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Zhi W, Ji G. Quantitative response relationships between nitrogen transformation rates and nitrogen functional genes in a tidal flow constructed wetland under C/N ratio constraints. WATER RESEARCH 2014; 64:32-41. [PMID: 25033023 DOI: 10.1016/j.watres.2014.06.035] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 06/17/2014] [Accepted: 06/25/2014] [Indexed: 05/27/2023]
Abstract
The present study explored treatment performance and nitrogen removal mechanisms of a novel tidal flow constructed wetland (TF CW) under C/N ratios ranging from two to 12. High and stable COD (83-95%), [Formula: see text] (63-80%), and TN (50-82%) removal efficiency were simultaneously achieved in our single-stage TF CW without costly aeration. Results showed that a C/N ratio exceeding six was required to achieve complete denitrification without [Formula: see text] and [Formula: see text] accumulation in the system. Molecular biological analyses revealed aerobic ammonia oxidation was the dominant [Formula: see text] removal pathway when the C/N ratio was less than or equal to six. However, when the C/N ratio was greater than six, anammox was notably enhanced, resulting in another primary [Formula: see text] removal pathway, in addition to the aerobic ammonia oxidation. Quantitative response relationships between nitrogen transformation rates and nitrogen functional genes were established, and these relationships confirmed that different nitrogen transformation processes were coupled at the molecular level (functional genes), and collaboratively contributed to nitrogen removal in the TF CW. Specifically, [Formula: see text] transformation rates were collectively determined by amoA, nxrA, anammox, narG, nirS, nirK, and nosZ; and TN removal was influenced primarily by amoA and anammox.
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Affiliation(s)
- Wei Zhi
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China; Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, United States
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
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Li F, Lu L, Zheng X, Ngo HH, Liang S, Guo W, Zhang X. Enhanced nitrogen removal in constructed wetlands: effects of dissolved oxygen and step-feeding. BIORESOURCE TECHNOLOGY 2014; 169:395-402. [PMID: 25069093 DOI: 10.1016/j.biortech.2014.07.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/30/2014] [Accepted: 07/01/2014] [Indexed: 06/03/2023]
Abstract
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.
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Affiliation(s)
- Fengmin Li
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
| | - Lun Lu
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Xiang Zheng
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Huu Hao Ngo
- School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Shuang Liang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Jinan 250100, China
| | - Wenshan Guo
- School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Xiuwen Zhang
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
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Badhe N, Saha S, Biswas R, Nandy T. Role of algal biofilm in improving the performance of free surface, up-flow constructed wetland. BIORESOURCE TECHNOLOGY 2014; 169:596-604. [PMID: 25105266 DOI: 10.1016/j.biortech.2014.07.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 07/10/2014] [Accepted: 07/13/2014] [Indexed: 06/03/2023]
Abstract
The role of algal biofilm in a pilot-scale, free-surface, up-flow constructed wetland (CW), was studied for its effect on chemical oxygen demand (COD), ammonia and phosphate removal during three seasons-autumn, winter and early spring. Effect of hydraulic retention time (HRT) was also investigated in presence and absence of algal biofilm. Principal Component Analysis was used to identify the independent factors governing the performance of CW. The study showed algal biofilm significantly improved nutrient removal, especially phosphate. Ammonia removal varied with HRT, biofilm and ambient temperature. Increase in biofilm thickness affected ammonia removal efficiency adversely. Algal biofilm-assisted COD removal compensated for reduced macrophyte density during winter. Two-way ANOVA test and the coefficients of dependent factors derived through multiple linear regression model confirmed role of algal biofilm in improving nutrient removal in CW. The study suggests that algal biofilm can be a green solution for bio-augmenting COD and nutrient removal in CW.
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Affiliation(s)
- Neha Badhe
- CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra 440020, India
| | - Shaswati Saha
- CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra 440020, India
| | - Rima Biswas
- CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra 440020, India.
| | - Tapas Nandy
- CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra 440020, India
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Zapater-Pereyra M, Gashugi E, Rousseau DPL, Alam MR, Bayansan T, Lens PNL. Effect of aeration on pollutants removal, biofilm activity and protozoan abundance in conventional and hybrid horizontal subsurface-flow constructed wetlands. ENVIRONMENTAL TECHNOLOGY 2014; 35:2086-94. [PMID: 24956803 DOI: 10.1080/09593330.2014.893024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The large area demand of constructed wetlands (CWs) is documented as a weak point that can be potentially reduced by applying active aeration. The aim of this study was, therefore, to understand the effects of aeration on the treatment performance, the biofilm activity, the protozoan population size and potential CW footprint reduction of different horizontal flow (HF) CW configurations. Two experimental periods were considered: a first period with low organic loading rate (OLR) and a second period with high OLR. Three HF CW configurations were compared: a conventional (control), an aerated and a hybrid CW (aerated followed by a non-aerated CW). The results obtained reinforced the competence of aerated CW for organic matter removal (81-89% of chemical oxygen demand) while for nitrogen elimination the control (19-24%) and hybrid (8-41%) systems performed better than the aerated system (-6% to 33%). Biofilm activity and protozoa abundance were distinctly higher at the inlet zones when compared with the outlet zones of all CWs, as well as in the aerated systems when compared with the non-aerated CWs. The protozoan abundance increased with an increase in the OLR and ciliates were found to be the dominant group. Overall, the active aeration highlighted the efficiency and stability of the CWs for organic matter removal and thus can be used as a promising tool to enhance microbial activity and grazing by protozoa; eventually reducing solid accumulation in the bed media. These beneficial effects contribute to reduce the CWs' area requirements.
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Ju X, Wu S, Zhang Y, Dong R. Intensified nitrogen and phosphorus removal in a novel electrolysis-integrated tidal flow constructed wetland system. WATER RESEARCH 2014; 59:37-45. [PMID: 24784452 DOI: 10.1016/j.watres.2014.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/19/2014] [Accepted: 04/04/2014] [Indexed: 06/03/2023]
Abstract
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.
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Affiliation(s)
- Xinxin Ju
- College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, PR China
| | - Shubiao Wu
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing 100083, PR China.
| | - Yansheng Zhang
- College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, PR China
| | - Renjie Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, Beijing 100083, PR China
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Chang Y, Wu S, Zhang T, Mazur R, Pang C, Dong R. Dynamics of nitrogen transformation depending on different operational strategies in laboratory-scale tidal flow constructed wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 487:49-56. [PMID: 24768911 DOI: 10.1016/j.scitotenv.2014.03.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/21/2014] [Accepted: 03/23/2014] [Indexed: 06/03/2023]
Abstract
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.
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Affiliation(s)
- Yongjiang Chang
- College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, PR China
| | - Shubiao Wu
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China.
| | - Tao Zhang
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, PR China
| | - Robert Mazur
- Department of Hydraulic and Sanitary Engineering, Faculty of Land Reclamation and Environmental Engineering, Poznan University of Life Sciences, Poland
| | - Changle Pang
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China
| | - Renjie Dong
- Key Laboratory of Clean Utilization Technology for Renewable Energy in Ministry of Agriculture, College of Engineering, China Agricultural University, 100083 Beijing, PR China
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Wu S, Kuschk P, Brix H, Vymazal J, Dong R. Development of constructed wetlands in performance intensifications for wastewater treatment: a nitrogen and organic matter targeted review. WATER RESEARCH 2014; 57:40-55. [PMID: 24704903 DOI: 10.1016/j.watres.2014.03.020] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/19/2014] [Accepted: 03/09/2014] [Indexed: 05/03/2023]
Abstract
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.
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Affiliation(s)
- Shubiao Wu
- College of Engineering, China Agricultural University, Qinghua Donglu 17, Haidian District, 100083 Beijing, PR China.
| | - Peter Kuschk
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, Leipzig D-04318, Germany
| | - Hans Brix
- Department of Bioscience, Aarhus University, Ole Worms Allé 1, 8000 Aarhus C., Denmark
| | - Jan Vymazal
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kymýcká 129, 165 21 Praha 6, Czech Republic
| | - Renjie Dong
- College of Engineering, China Agricultural University, Qinghua Donglu 17, Haidian District, 100083 Beijing, PR China
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42
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Wang YF, Wu Y, Pi N, Tam NFY. Investigation of microbial community structure in constructed mangrove microcosms receiving wastewater-borne polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 187:136-144. [PMID: 24487304 DOI: 10.1016/j.envpol.2014.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 12/30/2013] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
The study aims to examine relationships between microbial community structure and mixed pollutants of polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs) in constructed wetland microcosms, planted with Excoecaria agallocha or Kandelia obovata, two common mangrove plant species, and under two tidal regimes, everyday tidal (Te) and no tidal flooding (Tn). Results showed both microbial community structure and the retained amounts of pollutants were significantly determined by tidal regime, while the effect of plant species was small. Higher amounts of PAHs but lower amounts of PBDEs were always retained in sediments under Te than Tn regimes. Accordingly, temporal and vertical distributions of microbial community structure differed greatly between the two tidal regimes. Redundancy analysis further revealed significant correlation between a subgroup of the mixed PAHs and PBDEs with variation in microbial community structure. The findings will help to propose specific strategies to improve the bioremediation efficiency of constructed wetland.
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Affiliation(s)
- Ya-fen Wang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region.
| | - Yan Wu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region
| | - Na Pi
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region
| | - Nora Fung-yee Tam
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region.
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Saeed T, Al-Muyeed A, Afrin R, Rahman H, Sun G. Pollutant removal from municipal wastewater employing baffled subsurface flow and integrated surface flow-floating treatment wetlands. J Environ Sci (China) 2014; 26:726-736. [PMID: 25079402 DOI: 10.1016/s1001-0742(13)60476-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 06/03/2023]
Abstract
This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units (of the hybrid system) included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses (across the wetland units) illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates (656.0 g COD/(m(2)·day)) did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots (along with nitrification), and generation of organic carbon (by the dead macrophytes) to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efficiencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as: substantial input organics loading, hydraulic loading fluctuation, and seasonal variation.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka 1208, Bangladesh.
| | - Abdullah Al-Muyeed
- Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka 1208, Bangladesh
| | - Rumana Afrin
- Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka 1208, Bangladesh
| | - Habibur Rahman
- Department of Civil Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Guangzhi Sun
- School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811, Australia
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Hu Y, Zhao Y, Rymszewicz A. Robust biological nitrogen removal by creating multiple tides in a single bed tidal flow constructed wetland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 470-471:1197-204. [PMID: 24246943 DOI: 10.1016/j.scitotenv.2013.10.100] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/24/2013] [Accepted: 10/27/2013] [Indexed: 05/03/2023]
Abstract
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.
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Affiliation(s)
- Yuansheng Hu
- UCD Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland; Key Laboratory of Urban Stormwater System and Water Environment/R&D Centre for Sustainable Wastewater Treatment (Beijing University of Civil Engineering and Architecture), Ministry of Education, Beijing 100044, China.
| | - Yaqian Zhao
- UCD Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
| | - Anna Rymszewicz
- UCD Dooge Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, Newstead Building, University College Dublin, Belfield, Dublin 4, Ireland
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45
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Dordio A, Carvalho AJP. Constructed wetlands with light expanded clay aggregates for agricultural wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 463-464:454-461. [PMID: 23831791 DOI: 10.1016/j.scitotenv.2013.06.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/29/2013] [Accepted: 06/11/2013] [Indexed: 06/02/2023]
Abstract
Constructed wetlands (CWs) are receiving a renewed attention as a viable phytotechnology for treating agricultural wastewaters and for the removal of more specific pollutants, in particular recalcitrant ones. In this work, the performance of CW mesocosms using light expanded clay aggregates (LECA) as the bed's substrate and planted with Phragmites australis was investigated for treatment of olive mill wastewater (OMW), swine wastewater (SW) contaminated with oxytetracycline and water contaminated with herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid). Both wastewaters (OMW and SW) initially presented high organic matter content and total suspended solids which were removed by the system with efficiencies higher than 80%. Removal of polyphenols in OMW and nitrogen compounds in SW also showed similar or higher efficiencies in comparison with other treatment systems reported in the literature. The antibiotic oxytetracycline was completely removed from SW within the assay period in unplanted LECA beds, but planted beds allowed a significantly faster removal. In regard to water contaminated with MCPA, the results showed that LECA has a large sorption capacity for this herbicide (removal efficiencies of 56-97%). In general, considerably higher pollutant removal efficiencies were obtained when plants were used (up to 28% higher). The results obtained are indicative that CWs with LECA as substrate may be an adequate option for agricultural wastewater treatment.
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Affiliation(s)
- A Dordio
- Chemistry Department, University of Évora, Rua Romão Ramalho 59, 7000-676 Évora, Portugal; IMAR - Marine and Environmental Research Centre, University of Évora, Rua Romão Ramalho 59, 7000-676 Évora, Portugal.
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46
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Saeed T, Sun G. A review on nitrogen and organics removal mechanisms in subsurface flow constructed wetlands: dependency on environmental parameters, operating conditions and supporting media. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2012; 112:429-448. [PMID: 23032989 DOI: 10.1016/j.jenvman.2012.08.011] [Citation(s) in RCA: 325] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 08/05/2012] [Accepted: 08/09/2012] [Indexed: 06/01/2023]
Abstract
With the unique advantages of lower operational and maintenance cost, the applications of subsurface flow constructed wetlands for the treatment of wastewater have been increasing rapidly throughout the world. The removal of nitrogen and organics by such systems has gained substantial attention in recent years. In subsurface flow wetlands, the removal of pollutants often relies on a diverse range of co-existing physical, chemical and biological routes, which are vitally dependent on numerous environmental and operational parameters. This paper provides a comprehensive review of wetland structures, classic and novel nitrogen and organics removal mechanisms along with the key environmental parameters and operational conditions that enhance removal in subsurface flow wetland systems. The critical exploration identifies the major environmental parameters such as: pH, DO, and temperature, operational factors i.e. organic carbon availability, loading, feed mode, retention time, recirculation, harvesting, and the complex role (of both parameters) on classical nitrogen and organics removal pathways. Subsequently, the necessity of further extensive research on such factors, for promoting novel nitrogen removal routes in wetland systems has also been highlighted. The expansion of the review on the influence of the unconventional wetland matrix indicates that, the structural differences and inherent properties of these media can support substantial nitrogen and organics removal from wastewater, under optimal operating conditions. Overall, the critical review illustrates the necessity of a profound knowledge on the complicated inter-relationship between nitrogen and organics removal routes, governing environmental and operational parameters, and wetland matrix for improving the treatment performances of subsurface flow wetlands.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh; Department of Civil Engineering, Monash University, Clayton, Australia.
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47
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Saeed T, Afrin R, Muyeed AA, Sun G. Treatment of tannery wastewater in a pilot-scale hybrid constructed wetland system in Bangladesh. CHEMOSPHERE 2012; 88:1065-1073. [PMID: 22673399 DOI: 10.1016/j.chemosphere.2012.04.055] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 06/01/2023]
Abstract
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.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, Ahsanullah University of Science and Technology, Dhaka, Bangladesh.
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48
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Zhou S, Sakiyama Y, Riya S, Song X, Terada A, Hosomi M. Assessing nitrification and denitrification in a paddy soil with different water dynamics and applied liquid cattle waste using the ¹⁵N isotopic technique. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 430:93-100. [PMID: 22634555 DOI: 10.1016/j.scitotenv.2012.04.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 04/22/2012] [Accepted: 04/22/2012] [Indexed: 06/01/2023]
Abstract
Using livestock wastewater for rice production in paddy fields can remove nitrogen and supplement the use of chemical fertilizers. However, paddy fields have complicated water dynamics owing to varying characteristics and would influence nitrogen removal through nitrification followed by denitrification. Quantification of nitrification and denitrification is of great importance in assessing the influence of water dynamics on nitrogen removal in paddy fields. In this study, nitrification and nitrate reduction rates with different water dynamics after liquid cattle waste application were evaluated, and the in situ denitrification rate was determined directly using the (15)N isotopic technique in a laboratory experiment. A significant linear regression correlation between nitrification and the nitrate reduction rate was observed and showed different regression coefficients under different water dynamics. The regression coefficient in the continuously flooded paddy soil was higher than in the drained-reflooded paddy soil, suggesting that nitrate would be consumed faster in the flooded paddy soil. However, nitrification was limited and the maximum rate was only 13.3 μg Ng(-1)day(-1) in the flooded paddy soil with rice plants, which limited the supply of nitrate. In contrast, the drained-reflooded paddy soil had an enhanced nitrification rate up to 56.8 μg Ng(-1)day(-1), which was four times higher than the flooded paddy soil and further stimulated nitrate reduction rates. Correspondingly, the in situ denitrification rates determined directly in the drained-reflooded paddy soil ranged from 5 to 1035 mg Nm(-2)day(-1), which was higher than the continuously flooded paddy soil (from 5 to 318 mg Nm(-2)day(-1)) during the vegetation period. The nitrogen removal through denitrification accounted for 38.9% and 9.9% of applied nitrogen in the drained-reflooded paddy soil and continuously flooded paddy soil, respectively.
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Affiliation(s)
- Sheng Zhou
- Institute of Engineering, Tokyo University of Agriculture & Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
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Vucinic AA, Hrenovic J, Tepes P. Efficiency of subsurface flow constructed wetland with trickling filter. ENVIRONMENTAL TECHNOLOGY 2012; 33:1323-1330. [PMID: 22856305 DOI: 10.1080/09593330.2011.626798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
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.
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Affiliation(s)
- Aleksandra Anic Vucinic
- University of Zagreb, Faculty of Geotechnical Engineering, Hallerova aleja 7, 42000 Varazdin, Croatia
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Hu YS, Zhao YQ, Zhao XH, Kumar JLG. Comprehensive analysis of step-feeding strategy to enhance biological nitrogen removal in alum sludge-based tidal flow constructed wetlands. BIORESOURCE TECHNOLOGY 2012; 111:27-35. [PMID: 22357288 DOI: 10.1016/j.biortech.2012.01.165] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/24/2012] [Accepted: 01/26/2012] [Indexed: 05/31/2023]
Abstract
Step-feeding strategies have been extensively studied and comprehensively analyzed in this study for a four-stage alum sludge-based tidal flow constructed wetlands (AlS-TFCWs) system. Enhanced total nitrogen removal of 83% is achieved under high nitrogen loading rate of 19.1 g N/m(2)d. The key issues towards the success of a significant nitrogen removal in step-feeding TFCWs are the bed resting time (which provides better aeration for nitrification) and up flow stage/delayed input of side stream(s) (which ensure favorable environment for better denitrification). Simultaneous nitrification and denitrification (SND) was found effective in the 1st stage of the system and SND via nitrite is the main nitrogen conversion mechanism. The optimal influent distribution fraction for step-feeding purpose can be estimated from a theoretical basis, which is a function of the influent BCOD/TKN ratio. Therefore the influent distribution fraction should be adjusted according to the variety of influent characteristics, rather than a fixed value.
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Affiliation(s)
- Y S Hu
- Centre for Water Resources Research, School of Civil, Structural and Environmental Engineering, University College Dublin, Newstead Building, Belfield, Dublin 4, Ireland
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