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Saeed T, Al-Muyeed A, Zaman T, Hasan M, Ahmed T. Bioenergy-producing two-stage septic tank and floating wetland for onsite wastewater treatment: Circuit connection and external aeration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 359:121011. [PMID: 38678907 PMCID: PMC11129191 DOI: 10.1016/j.jenvman.2024.121011] [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: 10/05/2023] [Revised: 04/02/2024] [Accepted: 04/22/2024] [Indexed: 05/01/2024]
Abstract
This study designed a two-stage, electrode-integrated septic tank-floating wetland system and assessed their pollutant removal performances under variable operational conditions. The two-stage system achieved mean organic, nitrogen, phosphorus, and coliform removal percentages of 99, 78, 99, and 97%, respectively, throughout the experimental run. The mean metals (chromium, cadmium, nickel, copper, zinc, lead, iron, and manganese) removal percentages ranged between 81 and 98%. Accumulated sludge, filler media, and the hanging root mass contributed to pollutant removals by supporting physicochemical and biological pathways. The mean effluent organic concentration and coliform number across the two-stage system were 20 mg/L and 1682 CFU/100 mL, respectively, during the closed-circuit protocol, which was beneath the open-circuit-based performance profiles, i.e., 32 mg/L and 2860 CFU/100 mL, respectively. Effluent organic, nitrogen, phosphorus, metals, and coliform number ranges across the two-stage system were 9-17 mg/L, 13-24 mg/L, 1-1.5 mg/L, 0.001-0.2 mg/L, and 1410-2270 CFU/100 mL, respectively during intermittent and continuous aeration periods. The air supply rate differences influenced pollutant removal depending on the associated removal mechanisms. The non-aeration phase produced higher effluent pollutant concentrations than the aeration periods-based profiles. The overall mean power density production of the septic tank ranged between 107 and 596 mW/m3; 110 and 355 mW/m3 with the floating wetland. The bioenergy production capacity of the septic tank was positively correlated to external air supply rates. This study demonstrates the potential application of the novel bioenergy-producing septic tank-floating wetland system for wastewater treatment in decentralized areas.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh; Institute of Energy, Environment, Research and Development (IEERD), University of Asia Pacific, Dhaka, 1205, Bangladesh.
| | - Abdullah Al-Muyeed
- CWIS-FSM Support Cell, Department of Public Health Engineering, Government of the People's Republic of Bangladesh, Dhaka, 1000, Bangladesh.
| | - Takrim Zaman
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh.
| | - Mehedi Hasan
- ITN-BUET Centre for Water Supply and Waste Management, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
| | - Tanvir Ahmed
- ITN-BUET Centre for Water Supply and Waste Management, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh; Department of Civil Engineering, Bangladesh University of Engineering and Technology, Dhaka, 1000, Bangladesh.
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Soti A, Mohan Kulshreshtha N, Singh S, Samaria A, Brighu U, Dontireddy G, Banda S, Bhushan Gupta A. High rates of nitrogen removal in aerated VFCWs treating sewage through C-N-S cycle. BIORESOURCE TECHNOLOGY 2024; 399:130620. [PMID: 38518881 DOI: 10.1016/j.biortech.2024.130620] [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: 01/11/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
The efficiency of deep aerated vertical flow constructed wetlands (DA-VFCWs) being operated in Hyderabad, India, was evaluated herein using physicochemical analysis and 16S rRNA amplicon sequencing. The results showed 2-4-fold higher removal rate coefficients for Biochemical oxygen demand (1.32---3.53 m/d) and nitrogen (0.88--1.36 m/d) in DA-VFCWs than those of passive VFCWs. Elevated sulfate concentration in the DA-VFCWs effluent (84-113 mg/L) indicated possibility of sulfur-driven autotrophic denitrification (SDAD) as a major pathway operating in these wetlands besides the classical nitrogen removal pathways. The presence of nitrifiers (3.09-10.02 %), heterotrophic and aerobic denitrifiers (0.79-0.83 %), anammox bacteria (1.31-2.22 %) and SDAD bacteria (0.08-0.73 %) in the biofilm samples collected from the DA-VFCWs exemplify an interplay of Carbon-Nitrogen-Sulfur cycles in these systems. If proven, the presence of an operational SDAD pathway in DA-VFCWs can help reduce surface area requirement in VFCWs substantially besides alleviating biological clogging of the wetland substrate.
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Affiliation(s)
- Abhishek Soti
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India; Bluedrop Enviro Private Limited, 101, Vasantha Golden Residency Plot No- 521 and 536, Phillu Street, Raja Rajeswari Nagar, Kondapur, Telangana 500084, India
| | - Niha Mohan Kulshreshtha
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India
| | - Saurabh Singh
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India; Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58105, USA; Department of Civil Engineering, Swami Keshvanand Institute of Technology, Management and Gramothan, Jaipur 302017, India
| | - Akshat Samaria
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India
| | - Urmila Brighu
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India
| | - Gangadhara Dontireddy
- Bluedrop Enviro Private Limited, 101, Vasantha Golden Residency Plot No- 521 and 536, Phillu Street, Raja Rajeswari Nagar, Kondapur, Telangana 500084, India
| | - Sravan Banda
- Bluedrop Enviro Private Limited, 101, Vasantha Golden Residency Plot No- 521 and 536, Phillu Street, Raja Rajeswari Nagar, Kondapur, Telangana 500084, India
| | - Akhilendra Bhushan Gupta
- Department of Civil Engineering, Malaviya National Institute of Technology, JLN Marg, Jaipur 302017, India.
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Nigam M, Mishra P, Kumar P, Rajoriya S, Pathak P, Singh SR, Kumar S, Singh L. Comprehensive technological assessment for different treatment methods of leather tannery wastewater. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:124686-124703. [PMID: 35680745 DOI: 10.1007/s11356-022-21259-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 05/30/2022] [Indexed: 05/16/2023]
Abstract
The leather-making process necessitates large amounts of water and consequently generates tons of liquid waste as leather tannery wastewater (TWW) is disposed of directly in the open environment. Open disposal of untreated TWW into the natural environment causes an accumulation of various polluting compounds, including heavy metals, dyes, suspended solids inorganic matter, biocides, oils, tannins, and other toxic chemicals. It thus poses potential hazards to the environment and human health. This study primarily focuses on providing in-depth insight into the characteristics, treatment strategies, and regulatory frameworks for managing TWW in leather processing industries. Different technologies of conventional physico-chemical (equalization, coagulation, and adsorption), advanced approaches (Fenton oxidation, ozonation, cavitation), thermo-catalytic and biological treatments available to treat TWW, and their integrative approaches were also highlighted. This review also sheds light on the most frequently applied technologies to reduce contaminant load from TWW though there are several limitations associated with it such as being ineffective for large quantities of TWW, waste generation during treatment, and high operational and maintenance (O&M) costs. It is concluded that the sustainable alternatives applied in the current TWW technologies can minimize O&M costs and recirculate the treated water in the environment. The exhaustive observations and recommendations presented in this article are helpful in the industry to manage TWW and recirculate the water in a sustainable manner.
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Affiliation(s)
- Mohit Nigam
- Chemical Engineering Department, Raja Balwant Singh Engineering Technical Campus, Agra, 283105, India
| | - Puranjan Mishra
- Institute of Bioresource and Agriculture, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
| | - Pradeep Kumar
- Department of Chemical Engineering & Technology, Indian Institute of Technology (BHU), Varanasi, 221005, India
| | | | - Pankaj Pathak
- Department of Environmental Science, SRM University-AP, Amaravati, Andhra Pradesh, 522502, India
| | - Shraddha Rani Singh
- Chemical Engineering Department, Raja Balwant Singh Engineering Technical Campus, Agra, 283105, India
| | - Smita Kumar
- Department of Environmental Sciences, J.C. Bose University of Science & Technology, YMCA, Sector-6, Mathura Road, Faridabad, Haryana, 121006, India
| | - Lakhveer Singh
- Department of Chemistry, Sardar Patel University, Mandi, Himachal Pradesh, 175001, India
- Department of Civil Engineering, Centre for Research & Development, Chandigarh University, Mohali, Punjab, 140413, India
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Saeed T, Yadav AK, Miah MJ. Performance assessment of normal and electrode-assisted floating wetlands: influence of input pollutant loads, surface area, and positioning of anode electrodes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:18601-18616. [PMID: 36215020 DOI: 10.1007/s11356-022-23461-3] [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: 05/27/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
This study reports the design and development of microbial fuel cell (MFC) assisted floating wetlands and compares treatment removal performance with a normal (without electrodes) floating wetland. Both types of floating wetlands were planted with Phragmites plant and evaluated for real municipal wastewater treatment. The effective volume of each floating wetland was 0.5 m3. The floating wetlands were operated under variable hydraulic load rates, i.e., 20 and 60 mm/day. Mean 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), ammoniacal nitrogen (NH4-N), total nitrogen (TN), total phosphorus (TP), total suspended solids (TSS), and coliform removal percentages ranged between 71 and 96%, 72 and 94%, 62 and 86%, 58 and 75%, 82 and 97%, 64 and 92%, and 72 and 93%, respectively within the normal and electrode-assisted MFC integrated floating wetlands. The electrode-integrated floating wetlands showed better pollutant removal performance than the normal system under unstable input pollutant loading conditions. Nitrogen and organic matter removals were achieved through both electrochemically active and inactive microbial removal routes. Physical separation processes, such as filtration and sedimentation, contributed to phosphorus, solids, and coliform removal. Plant uptake contributed to micro-scale nitrogen (≤ 1%) and phosphorus (≤ 0.1%) removal. Increment of hydraulic/pollutant load improved organic removal but decreased nutrient removal performance of the normal, electrode-integrated floating wetlands. The electrode-integrated floating wetlands produced power densities ranging between 0.7 and 1.4 mW/m3, and 0.2 and 2.3 mW/m3 during lower, upper input loading ranges, respectively. Bioenergy production of the electrode-integrated floating wetlands varied within the two operational periods due to a wider range of electrochemically inactive microbial populations in real wastewater that interfered with electrochemical organic matter oxidation. The positioning difference of the anode electrodes was a significant factor that improved pollutant removal within the electrode-integrated floating wetlands compared to the other variable, i.e., anode electrodes surface area.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh.
| | - Asheesh Kumar Yadav
- Department of Chemical and Environmental Technology, Rey Juan Carlos University, 28933, MostolesMadrid, Spain
| | - Md Jihad Miah
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh
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Saeed T, Majed N, Miah MJ, Yadav AK. A comparative landfill leachate treatment performance in normal and electrodes integrated hybrid constructed wetlands under unstable pollutant loadings. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155942. [PMID: 35580676 DOI: 10.1016/j.scitotenv.2022.155942] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 05/02/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
This study provides a comparative pollutant removal performance assessment between organic or construction materials-based four hybrid wetland systems that received landfill leachate. The hybrid systems included vertical flow (VF) followed by horizontal flow (HF)-based unplanted and planted systems, and planted electrodes incorporated microbial fuel cell (MFC) integrated hybrid wetlands systems. All the systems were run in free-draining mode. Overall mean chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) removal percentage of the hybrid systems ranged between 81 and 99%, 82 and 96%, 74 and 99%, respectively, under unstable input pollutant loading conditions. Additionally, up to 27% organic and up to 14% nitrogen removal improvement was observed in electrodes integrated free-draining VF wetlands. Free-draining and additional oxygen availability from atmospheric diffusion, rootzone improved the removal performance of MFC-based VF wetlands. Input load increment decreased organic, nutrient removals in second stage HF units due to saturated media. The chemical composition of the employed media supported biotic, abiotic organic, nutrient removal pathways. Nutrient accumulation percentage in plants tissue was very low, i.e., ≤3%. Bioenergy production across the MFC-based VF-HF wetlands decreased with input pollutant load increment. The single anode electrode-based VF wetland achieved maximum power density production, i.e., 294 mW/m2.. The electrodes integrated hybrid systems achieved comparatively stable removal performance despite input pollutant/hydraulic load variation.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka 1205, Bangladesh.
| | - Nehreen Majed
- Department of Civil Engineering, University of Asia Pacific, Dhaka 1205, Bangladesh
| | - Md Jihad Miah
- Department of Civil Engineering, University of Asia Pacific, Dhaka 1205, Bangladesh
| | - Asheesh Kumar Yadav
- Department of Chemical and Environmental Technology, Rey Juan Carlos University, Mostoles, 28933, Madrid, Spain
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6
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Nitrogen and Phosphorus Removal Efficiency and Denitrification Kinetics of Different Substrates in Constructed Wetland. WATER 2022. [DOI: 10.3390/w14111757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Constructed wetlands (CWs) are generally used for wastewater treatment and removing nitrogen and phosphorus. However, the treatment efficiency of CWs is limited due to the poor performance of various substrates. To find appropriate substrates of CWs for micro-polluted water treatment, zeolite, quartz sand, bio-ceramsite, porous filter, and palygorskite self-assembled composite material (PSM) were used as filtering media to treat slightly polluted water with the aid of autotrophic denitrifying bacteria. PSM exhibited the most remarkable nitrogen and phosphorus removal performance among these substrates. The average removal efficiencies of ammonia nitrogen, total nitrogen, and total phosphorus of PSM were 66.4%, 58.1%, and 85%, respectively. First-order continuous stirred-tank reactor (first-order-CSTR) and Monod continuous stirred-tank reactor (Monod-CSTR) models were established to investigate the kinetic behavior of denitrification nitrogen removal processes using different substrates. Monod-CSTR model was proven to be an accurate model that could simulate nitrate nitrogen removal performance in vertical flow constructed wetland (VFCWs). Moreover, PSM demonstrated significant pollutant removal capacity with the kinetics coefficient of 2.0021 g/m2 d. Hence, PSM can be considered as a promising new type of substrate for micro-polluted wastewater treatment, and Monod-CSTR model can be employed to simulate denitrification processes.
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Ferreira AG, Borges AC, Rosa AP. Comparison of first-order kinetic models for sewage treatment in horizontal subsurface-flow constructed wetlands. ENVIRONMENTAL TECHNOLOGY 2021; 42:4511-4518. [PMID: 32404025 DOI: 10.1080/09593330.2020.1769741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
There are several techniques for sizing horizontal subsurface-flow constructed wetlands systems (CWs), and mathematical models have been frequently used for this purpose because they more accurately represent the liquid behaviour in these reactors. The P-k-C* model has already been used in the prediction of organic matter removal in CWs, but it has been little explored in the literature. On other hand, the model proposed by Chan and Chu [Modeling the reaction kinetics of Fenton's process on the removal of atrazine. Chemosphere. 2003;51(4):305-311] was not known for prediction of organic matter removal in CW systems. In the present work, the kinetic data for chemical oxygen demand (COD) removal of 28 horizontal subsurface-flow constructed wetlands were used to compare the performance of two pseudo-first-order kinetic models (P-k-C* model and model from Chan and Chu. The comparisons of nonlinear regressions were performed considering Akaike information criterion (AIC), root-mean-square error (RMSE), and adjusted coefficient of determination (Radj2). In general, both models were able to provide good predictions of relative remaining concentration (C/C0). However, the Chan and Chu model produced higher adjustment coefficients, showing the potential to be used in modelling and simulation of the degradation kinetics of organic matter in wetlands.
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Affiliation(s)
- Aline Gomes Ferreira
- Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brasil
| | | | - André Pereira Rosa
- Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brasil
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Saeed T, Miah MJ, Khan T. Intensified constructed wetlands for the treatment of municipal wastewater: experimental investigation and kinetic modelling. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:30908-30928. [PMID: 33594561 DOI: 10.1007/s11356-021-12700-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
This study reports organics and nutrient removal performances of the intensified constructed wetlands, i.e., tidal flow-based microbial fuel cell (MFC) and tidal flow wetlands that received municipal wastewater. The wetland systems were filled with organic (coco peat, biochar) or waste (Jhama brick, steel slag) materials, planted with Phragmites australis or Chrysopogon zizanioides (Vetiver) species, and operated under three flood periods: 8, 16, 24 h. Input ammonia nitrogen (NH3-N), total nitrogen (TN), phosphorus (P), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) load across the wetland systems ranged between 3-27, 12-78, 0.1-23, 36-1130, and 11-281 g/m2day, respectively; mean removal percentages were 60-83, 74-84, 95-100, 94-98, and 93-97%, respectively, throughout the experimental run. The wetland systems achieved similar organics and P removals; operational and media variation did not influence removal kinetics. All wetland systems achieved the highest TN removal (76-87%) when subjected to 24-h flood period. TN removal performances of waste material-based wetlands were comparable to organic media-based systems. Tidal flow-based MFC wetlands achieved better TN removal than tidal flow wetlands because of supplementary electron production through fuel cell-based organics degradation kinetics. Maximum power production rates across the tidal flow-based MFC wetlands ranged between 53 and 57 mW/m2. Monod kinetics-based continuous stirred tank reactor (CSTR) models predicted NH3-N, TN, and COD removals (in wetland systems) more accurately. Kinetic models confirmed the influence of substrate (i.e., pollutant) and environmental parameters on pollutant removal routes.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh.
| | - Md Jihad Miah
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh
| | - Tanbir Khan
- Department of Civil Engineering, University of Asia Pacific, Dhaka, 1205, Bangladesh
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Guo CQ, Cui YL. Improved solute transport and pollutant degradation model of free water surface constructed wetlands considering significant linear correlation between model parameters. BIORESOURCE TECHNOLOGY 2021; 327:124817. [PMID: 33578355 DOI: 10.1016/j.biortech.2021.124817] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 06/12/2023]
Abstract
To unify the structures of solute transport and pollutant degradation models and evaluate the wetland performance conveniently, a pollutant degradation model combining first-order kinetics with the hybrid solute transport model (plug flow with dispersion + continuous stirred-tank reactor, PFD + CSTR) was developed. Orthogonal tests revealed significant correlation between the model parameters, and the original models were optimized via linear substitution of parameters. The improved PFD + CSTR solute transport model exhibited a satisfactory fit with the original model, and the average relative errors of the determination coefficient (R2) and correlation coefficient were <5%. The multiple linear regressions between the hydraulic indicators and model parameters were reconstructed and exhibited consistent structures between different stages. The degradation constant kaTN between the original and improved models exhibited high consistency (R2 = 0.982). Conclusively, the improved models exhibited good consistency with the original models and allowed rapid and accurate performance evaluation.
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Affiliation(s)
- Chang-Qiang Guo
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China; State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
| | - Yuan-Lai Cui
- State Key Laboratory of Water Resource and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China.
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Li X, Zhu W, Meng G, Zhang C, Guo R. Efficiency and kinetics of conventional pollutants and tetracyclines removal in integrated vertical-flow constructed wetlands enhanced by aeration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 273:111120. [PMID: 32745882 DOI: 10.1016/j.jenvman.2020.111120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/04/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
The integrated vertical-flow constructed wetland (IVCW) is considered as a potential alternative for domestic wastewater treatment of towns and small cities. Oxygen supply is the main limitation of pollutants removal in IVCWs. In the present study, a field experiment was conducted to evaluate the capacity and kinetics of pollutants removal in IVCWs with/without artificial aeration. Two IVCWs constructed with Canna indica and Phragmites australis were running in continuous flow to remove high concentrations of conventional pollutants and low concentrations of tetracyclines (TETs), which are at similar levels of domestic wastewater. The results showed that IVCWs had a good performance on COD, phosphorus, and TETs with removal efficiencies over 80%, 64%, and 75%, respectively, with a hydraulic retention time (HRT) of 3.0 d. However, the removal of nitrogen was limited, showing as TN removal efficiency of about 30%. The IVCW with Phragmites australis had a higher removal efficiency and rate. A kinetics based on Monod Equation and solved with Matlab 2018a could describe the degradation of conventional pollutants. Artificial aeration improved the oxygen supply and remarkably raised the removal capacity for COD, N, and P in IVCWs. The q1/2 values, which was defined as the average removal loading before half of the pollutants was removed and represented the removal capacity without limitation of pollutants concentration, were increased by 5-30 times after aeration. In conclusion, IVCWs could remove conventional pollutants and TETs simultaneously showing a great potential in domestic wastewater treatment. Artificial aeration enhanced removal capacity of IVCWs on conventional pollutants while showed little influence on TETs.
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Affiliation(s)
- Xuhui Li
- National Demonstration Center for Environment and Planning, Henan University, Kaifeng, 475004, China; Henan Engineering Research Centre for Control & Remediation of Soil Heavy Metal Pollution, Henan University, Kaifeng, 475004, China.
| | - Weigang Zhu
- National Demonstration Center for Environment and Planning, Henan University, Kaifeng, 475004, China; Henan Engineering Research Centre for Control & Remediation of Soil Heavy Metal Pollution, Henan University, Kaifeng, 475004, China
| | - Gengjian Meng
- National Demonstration Center for Environment and Planning, Henan University, Kaifeng, 475004, China; Henan Engineering Research Centre for Control & Remediation of Soil Heavy Metal Pollution, Henan University, Kaifeng, 475004, China
| | - Chaosheng Zhang
- National Demonstration Center for Environment and Planning, Henan University, Kaifeng, 475004, China; School of Geography, Archaeology & Irish Studies & Ryan Institute, National University of Ireland, Galway, H91 CF50, Ireland
| | - Ruichao Guo
- National Demonstration Center for Environment and Planning, Henan University, Kaifeng, 475004, China; Henan Engineering Research Centre for Control & Remediation of Soil Heavy Metal Pollution, Henan University, Kaifeng, 475004, China.
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Li Y, Zhang H, Zhu L, Chen H, Du G, Gao X, Pu Y. Evaluation of the long-term performance in a large-scale integrated surface flow constructed wetland-pond system: A case study. BIORESOURCE TECHNOLOGY 2020; 309:123310. [PMID: 32325377 DOI: 10.1016/j.biortech.2020.123310] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
Limited information is available in regards to the long-term treatment performance of large-scale integrated surface flow constructed wetland-pond (ISFWP) system improving drinking water source. This study aimed to investigate the treatment performance of a large-scale ISFWP system for the improvement of drinking water source. During five years of operation, the average effluent water quality in the ISFWP system could comply with Chinese Environmental Quality Standards for Drinking Water Source. The average removal efficiencies of permanganate index (CODMn), ammonia nitrogen, total nitrogen (TN), total phosphorus, and fecal coliforms were 7.6%, 44.3%, 42.9%, 50.8%, and 88.6%, respectively. The treatment performance in the ISFWP system was stable during the operation time, while TN removal efficiency declined by 38.2% after five years of operation. Moreover, contaminants removal efficiencies were not subject to change of season, except for CODMn and TN. Consequently, efficient and sustainable contaminants removal in the large-scale ISFWP system still possessed challenges, especially for CODMn and TN.
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Affiliation(s)
- Yiping Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
| | - Haikuo Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
| | - Liqin Zhu
- College of Marxism, Hohai University, Nanjing 210098, China.
| | - Hongwei Chen
- Yancheng Water Conservancy Bureau of Jiangsu Province, Yancheng 224001, China
| | - Guanchao Du
- Yancheng Yanlong Lake Drinking Water Source Management Department, Yancheng 224007, China
| | - Xu Gao
- Yancheng Yanlong Lake Drinking Water Source Management Department, Yancheng 224007, China
| | - Yashuai Pu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China
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Gajewska M, Skrzypiec K, Jóźwiakowski K, Mucha Z, Wójcik W, Karczmarczyk A, Bugajski P. Kinetics of pollutants removal in vertical and horizontal flow constructed wetlands in temperate climate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137371. [PMID: 32092523 DOI: 10.1016/j.scitotenv.2020.137371] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/03/2020] [Accepted: 02/15/2020] [Indexed: 06/10/2023]
Abstract
This paper reports a comparative study on kinetics of organic matter expressed as BOD5 and nitrogen removal in constructed wetlands operated in Poland. Analyzed data were collected at eight wetland systems, composed of subsurface flow beds: horizontal flow (HF) and vertical flow (VF), in different number and sequences. The analysis involved particularly mass removal rates (MRR) and first-order removal rate coefficients of BOD5 and total nitrogen (kA and kv for VF and HF filters, respectively, and k20 as a parameter averaged for a temperature of 20 °C). It was found that the higher the load of pollutants applied to the beds, the higher MRR values were obtained. The average k-rates in analyzed systems were mostly lower than those reported in the literature, especially in the case of total nitrogen. Its removal obtained in horizontal flow beds was kv = 0.002-0.042 d-1, while in vertical flow systems kA varied from 0.007 m d-1 to 0.0037 m d-1. According to data given by previous studies, first-order reaction rates for nitrogen removal varied in range from kv = 0.048 d-1 to kv = 0.19 d-1 and kA from 0.007 to 0.1 m d-1 in HF and VF beds, respectively. Regarding BOD5 shown in literature, removal rate kv for HF beds varied from 0.071 to 6.11 d-1, and kA for VF beds varied from 0.019 to 1.0 m d-1, while in this study lower k-rates were obtained: kv = 0.005-0.085 d-1 and kA = 0.015-0.130 m d-1. Relatively long monitoring period, for some of constructed wetland up to 16 years, resulted in good data set and enables creation of the graphs, which could be helpful in evaluation and designing of constructed wetlands for PE bigger than 50, in moderate climate conditions.
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Affiliation(s)
- Magdalena Gajewska
- Dept. of Water and Wastewater Technology, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Narutowicza St. 11/12, 80-233 Gdańsk, Poland
| | - Katarzyna Skrzypiec
- Dept. of Water and Wastewater Technology, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Narutowicza St. 11/12, 80-233 Gdańsk, Poland
| | - Krzysztof Jóźwiakowski
- Dept. of Environmental Engineering and Geodesy, Faculty of Production Engineering, University of Life Sciences in Lublin, Akademicka St. 13, 20-950 Lublin, Poland.
| | - Zbigniew Mucha
- Dept. of Environmental Technologies, Faculty of Environmental Engineering, Cracow University of Technology, Warszawska St. 24, 31-155 Kraków, Poland
| | - Włodzimierz Wójcik
- Dept. of Civil Engineering, Krosno State College, Rynek St. 1, 38-400 Krosno, Poland
| | - Agnieszka Karczmarczyk
- Dept. of Environmental Development, Institute of Environmental Engineering, Warsaw University of Life Sciences-SGGW, Nowoursynowska St. 159, 02-776 Warsaw, Poland
| | - Piotr Bugajski
- Dept. of Sanitary Engineering and Water Management, University of Agriculture in Kraków, Al. Mickiewicza St. 24/28, 30-059 Kraków, Poland
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Li X, Li Y, Li Y, Wu J. Enhanced nitrogen removal and quantitative analysis of removal mechanism in multistage surface flow constructed wetlands for the large-scale treatment of swine wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 246:575-582. [PMID: 31202022 DOI: 10.1016/j.jenvman.2019.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/31/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
Constructed wetlands have recently been studied as a form of green infrastructure for the enhanced removal of nitrogen (N). This study aimed to demonstrate the use of multistage surface flow constructed wetland (SFCW) for treatment of swine wastewater. The results showed chemical oxygen demand (COD), total nitrogen (TN), NH4+, and NO3- removal rates of 16.3 g m-2 d-1, 9.14 g m-2 d-1, 7.75 g m-2 d-1, and 45.49 mg m-2 d-1, respectively. The sediment and plant absorption N rates were 2.44 g m-2 d-1, and 1.24 g m-2 d-1, respectively. Moreover, the microbial process which is the primary process, by which N is removed, accounted for 56.75-65.35%. Quantitative polymerase chain reaction (qPCR) revealed the highest microbial abundance in the segment of the SFCW with high N concentration. Ammonia-oxidizing bacteria (AOB) and nirK could be primarily responsible for the high removal rate of N. Factors like pH, DO, COD, N, and OM play an important role in influencing microbial abundance. It is suggested that the multistage SFCW has a promising future for the large scale treatment of swine wastewater.
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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, PR China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China
| | - Yuyuan Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China.
| | - Yong Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China
| | - Jinshui Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China
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Kabenge I, Ouma G, Aboagye D, Banadda N. Performance of a constructed wetland as an upstream intervention for stormwater runoff quality management. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:36765-36774. [PMID: 30414031 DOI: 10.1007/s11356-018-3580-z] [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: 03/27/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
In most developing countries, stormwater runoff has had significant impacts on aquatic environment by directly causing pollution of receiving water and reduction in treatment performance of wastewater treatment plants. With increasing encroachment on natural wetlands in Uganda, constructed wetlands offer a feasible option for the environment to cope up and buffer the impact of pollutants from the ever-increasing urban masses. This study investigated the performance efficiencies of three configurations (varied by the substrate used) of microcosm wetlands to remove physicochemical parameters from stormwater runoff in Uganda. The parameters monitored included chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP). Hydraulic retention times (HRTs) of 2, 4, 6, and 8 days were studied. The mean concentrations of the physicochemical parameters in the runoff were 219.4 ± 12.8 mg/L COD, 77.4 ± 8.3 mg/L TSS, 9.0 ± 0.4 mg/L TN, and 1.6 ± 0.1 mg/L TP. Configuration A, vegetated with cattail (Typha latifolia) and bulrush (Scirpus lacustris), achieved maximum COD removal of 75.9% (HRT = 6 days), TN removal of 72.8% (HRT = 8 days), and TP removal of 62.8% (HRT = 8 days). Configuration C, the control, with no substrate, achieved the highest TSS removal of 75.6%. The results suggest that vegetated microcosm constructed wetlands can potentially be used to pre-treat stormwater within the catchment. However, an upstream sedimentation process unit is required to enhance their performance and to avoid premature clogging of the wetlands by TSS. The pre-treated stormwater reduces pollutant load into wastewater treatment plants and consequently better raw water quality for water treatment plants.
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Affiliation(s)
- Isa Kabenge
- Department of Agricultural and Biosystems Engineering, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Godfrey Ouma
- Department of Agricultural and Biosystems Engineering, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Dominic Aboagye
- Department of Agricultural and Biosystems Engineering, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Noble Banadda
- Department of Agricultural and Biosystems Engineering, Makerere University, P. O. Box 7062, Kampala, Uganda
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Zhao X, Hu Y, Zhao Y, Kumar L. Achieving an extraordinary high organic and hydraulic loadings with good performance via an alternative operation strategy in a multi-stage constructed wetland system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:11841-11853. [PMID: 29446020 DOI: 10.1007/s11356-018-1464-x] [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: 11/17/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
In this study, a high organic loading rate of 58-146 g BOD5/m2 day with a hydraulic loading rate (HLR) of 1.63 m3/m2 day and retention time (RT) of 16 h was achieved to maximize the treatment capacity of a four-stage alum sludge-based constructed wetland (CW) system. An alternative operation strategy, i.e., the first stage anaerobic up-flow and the remaining stage tidal flow with effluent recirculation, was investigated to achieve the goal with good treatment performance of 82% COD, 91% BOD5, 92% SS, 94% NH4-N, and 82% TN removal. Two kinetic models, i.e., first-order model and Monod plus continuous stirred-tank reactor (CSTR) flow model, were employed for predicting the removal dynamics. The results showed that the tidal flow strategy enhances oxygen transport and diffusion, thus improving reduction of organics and NH4-N. Effluent recirculation could further increase elimination of organics by extending the interaction time and also benefit the denitrification process. In addition, denitrification could be further enhanced by anaerobic up-flow in the first stage.
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Affiliation(s)
- Xiaohong Zhao
- Key Laboratory of Water Supply and Drainage, Ministry of Housing and Urban-Rural Development, Chang'an University, Xi'an, 710061, People's Republic of China
| | - Yuansheng Hu
- 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, People's Republic of China
| | - Yaqian Zhao
- Key Laboratory of Water Supply and Drainage, Ministry of Housing and Urban-Rural Development, Chang'an University, Xi'an, 710061, People's Republic of China.
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland.
| | - Lordwin Kumar
- UCD Dooge Centre for Water Resources Research, School of Civil Engineering, University College Dublin, Newstead, Belfield, Dublin 4, Ireland
- Department of Soil Water Land Engineering and Management, Vaugh School of Agricultural Engineering and Technology, Sam Higginbottom Institute of Agriculture, Technology & Sciences, Allahabad, India
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Wu H, Fan J, Zhang J, Ngo HH, Guo W. Large-scale multi-stage constructed wetlands for secondary effluents treatment in northern China: Carbon dynamics. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 233:933-942. [PMID: 29029835 DOI: 10.1016/j.envpol.2017.09.048] [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: 05/03/2017] [Revised: 09/12/2017] [Accepted: 09/16/2017] [Indexed: 06/07/2023]
Abstract
Multi-stage constructed wetlands (CWs) have been proved to be a cost-effective alternative in the treatment of various wastewaters for improving the treatment performance as compared with the conventional single-stage CWs. However, few long-term full-scale multi-stage CWs have been performed and evaluated for polishing effluents from domestic wastewater treatment plants (WWTP). This study investigated the seasonal and spatial dynamics of carbon and the effects of the key factors (input loading and temperature) in the large-scale seven-stage Wu River CW polishing domestic WWTP effluents in northern China. The results indicated a significant improvement in water quality. Significant seasonal and spatial variations of organics removal were observed in the Wu River CW with a higher COD removal efficiency of 64-66% in summer and fall. Obvious seasonal and spatial variations of CH4 and CO2 emissions were also found with the average CH4 and CO2 emission rates of 3.78-35.54 mg m-2 d-1 and 610.78-8992.71 mg m-2 d-1, respectively, while the higher CH4 and CO2 emission flux was obtained in spring and summer. Seasonal air temperatures and inflow COD loading rates significantly affected organics removal and CH4 emission, but they appeared to have a weak influence on CO2 emission. Overall, this study suggested that large-scale Wu River CW might be a potential source of GHG, but considering the sustainability of the multi-stage CW, the inflow COD loading rate of 1.8-2.0 g m-2 d-1 and temperature of 15-20 °C may be the suitable condition for achieving the higher organics removal efficiency and lower greenhouse gases (GHG) emission in polishing the domestic WWTP effluent. The obtained knowledge of the carbon dynamics in large-scale Wu River CW will be helpful for understanding the carbon cycles, but also can provide useful field experience for the design, operation and management of multi-stage CW treatments.
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Affiliation(s)
- Haiming Wu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Jinan 250100, PR China
| | - Jinlin Fan
- National Engineering Laboratory of Coal-Fired Pollutants Emission Reduction, Shandong University, Jinan 250061, PR China
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Jinan 250100, PR China.
| | - Huu Hao Ngo
- School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Wenshan Guo
- School of Civil and Environmental Engineering, University of Technology Sydney, Broadway, NSW 2007, Australia
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17
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Wu H, Zhang J, Guo W, Liang S, Fan J. Secondary effluent purification by a large-scale multi-stage surface-flow constructed wetland: A case study in northern China. BIORESOURCE TECHNOLOGY 2018; 249:1092-1096. [PMID: 29137931 DOI: 10.1016/j.biortech.2017.10.099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
Assessment of treatment performance in the large-scale constructed wetland (CW) for secondary effluent purification remains limited. The aim of this case study was to therefore to investigate the long-term treatment capacity of organics and ammonium pollutants in a large-scale multi-stage surface-flow (SF) CW fed with secondary effluents from the wastewater treatment plants (WWTPs) in northern China. The results for two-and-half-year study period indicated that the water quality parameters including chemical oxygen demand (COD) and ammonium (NH4+-N) met the Chinese Grade III of Environmental Quality Standards. The mass reductions of COD and NH4+-N were 53% (4032 kg ha-1 y-1) and 72% (511 kg ha-1 y-1), respectively. However, there was a significant positive correlation between influent loads and treatment performance. The optimal loading of 2.5 g m-2 d-1 for COD and 0.3 g m-2 d-1 for NH4+-N could be recommended for designing the sustainable large-scale multi-stage SF CW wastewater treatments.
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Affiliation(s)
- Haiming Wu
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, PR China
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Jinan 250100, PR China.
| | - Wenshan Guo
- 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, PR China
| | - Jinlin Fan
- National Engineering Laboratory of Coal-Fired Pollutants Emission Reduction, Shandong University, Jinan 250061, PR China
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Ausland H, Ward A, Licht L, Just C. Enhanced vadose zone nitrogen removal by poplar during dormancy. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2015; 17:729-736. [PMID: 26030360 DOI: 10.1080/15226514.2014.987371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A pilot-scale, engineered poplar tree vadose zone system was utilized to determine effluent nitrate (NO3(-)) and ammonium concentrations resulting from intermittent dosing of a synthetic wastewater onto sandy soils at 4.5°C. The synthetic wastewater replicated that of an industrial food processor that irrigates onto sandy soils even during dormancy which can leave groundwater vulnerable to NO3(-) contamination. Data from a 21-day experiment was used to assess various Hydrus model parameterizations that simulated the impact of dormant roots. Bromide tracer data indicated that roots impacted the hydraulic properties of the packed sand by increasing effective dispersion, water content and residence time. The simulated effluent NO3(-) concentration on day 21 was 1.2 mg-N L(-1) in the rooted treatments compared to a measured value of 1.0 ± 0.72 mg-N L(-1). For the non-rooted treatment, the simulated NO3(-) concentration was 4.7 mg-N L(-1) compared to 5.1 ± 3.5 mg-N L(-1) measured on day 21. The model predicted a substantial "root benefit" toward protecting groundwater through increased denitrification in rooted treatments during a 21-day simulation with 8% of dosed nitrogen converted to N2 compared to 3.3% converted in the non-rooted test cells. Simulations at the 90-day timescale provided similar results, indicating increased denitrification in rooted treatments.
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Affiliation(s)
- Hayden Ausland
- a Department of Civil and Environmental Engineering , University of Iowa , Iowa City , IA
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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: 327] [Impact Index Per Article: 27.3] [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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Saeed T, Sun G. Kinetic modelling of nitrogen and organics removal in vertical and horizontal flow wetlands. WATER RESEARCH 2011; 45:3137-3152. [PMID: 21481434 DOI: 10.1016/j.watres.2011.03.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 03/07/2011] [Accepted: 03/15/2011] [Indexed: 05/30/2023]
Abstract
This paper provides a comparative evaluation of the kinetic models that were developed to describe the biodegradation of nitrogen and organics removal in wetland systems. Reaction kinetics that were considered in the model development included first order kinetics, Monod and multiple Monod kinetics; these kinetics were combined with continuous-stirred tank reactor (CSTR) or plug flow pattern to produce equations to link inlet and outlet concentrations of each key pollutants across a single wetland. Using three statistical parameters, a critical evaluation of five potential models was made for vertical and horizontal flow wetlands. The results recommended the models that were developed based on Monod models, for predicting the removal of nitrogen and organics in a vertical and horizontal flow wetland system. No clear correlation was observed between influent BOD/COD values and kinetic coefficients of BOD(5) in VF and HF wetlands, illustrating that the removal of biodegradable organics was insensitive to the nature of organic matter. Higher effluent COD/TN values coincided with greater denitrification kinetic coefficients, signifying the dependency of denitrification on the availability of COD in VF wetland systems. In contrast, the trend was opposite in HF wetlands, indicating that availability of NO(3)-N was the main limiting step for nitrogen removal. Overall, the results suggested the possible application of the developed alternative predictive models, for understanding the complex biodegradation routes of nitrogen and organics removal in VF and HF wetland systems.
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Affiliation(s)
- Tanveer Saeed
- Department of Civil Engineering, Building 60, Monash University, Clayton, Victoria 3800, Australia.
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