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Zhang B, Cui Y, Liao B, Tang C, Shu Y. Experimental checking and modeling of the influence of operation conditions on the first order kinetic constants in free water surface wetlands. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 331:117348. [PMID: 36706603 DOI: 10.1016/j.jenvman.2023.117348] [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: 11/18/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
The most commonly used model in constructed wetlands is the first-order removal model, and first order kinetic constants (k) are the key parameters. The presumption is often made that k are constants. However, it is possible that k are functions of operating conditions, but the influence of operation conditions on k is unclear. In this study, response surface methodology was used to explore the variation patterns of ka (area rate constants) and kV (volume rate constants) for the removal of total nitrogen (TN) and total phosphorus (TP) in free water surface (FWS) wetlands. The experimental variables included hydraulic loading rate (HLR), water depth, and inlet concentration (Cin). The results showed that kV was more variable than ka, and the area-based first-order model is more suitable for simulating TN and TP in FWS wetlands. Inlet concentration (Cin) was significant for ka; Cin and water depth were significant for kV; HLR and the interaction between factors were insignificant. The effects of Cin on ka and kV can be described by an upward convex quadratic curve, while the effect of water depth on kV demonstrates a downward convex quadratic curve. The first-order area rate constant for TN removal was given by k = -47.66 + 22.01 Cin - 1.154 Cin2; the first-order area rate constant for TP removal was given by k = -27.75 + 95.88 Cin - 30.73 Cin2. Based on the variation patterns, the traditional k-C model was modified to the kψ-C model. The kψ-C model produced the best results at simulating the outlet concentration and removal efficiency (RE).
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Affiliation(s)
- Bochao Zhang
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
| | - Yuanlai Cui
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
| | - Bin Liao
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
| | - Chi Tang
- Zhanghe Engineering Management Bureau, Jingmen, 448156, Hubei, China
| | - Yonghong Shu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China
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Wei D, Singh RP, Li Y, Fu D. Nitrogen removal efficiency of surface flow constructed wetland for treating slightly polluted river water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:24902-24913. [PMID: 32342414 DOI: 10.1007/s11356-020-08393-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/11/2020] [Indexed: 06/11/2023]
Abstract
Restoration and water quality improvement of malodorous as well as slightly polluted rivers have been the global focus for environmental protection research and the development and construction of sponge cities. To date, constructed wetlands have been proven to be one of efficient methods to improve water quality. Nitrogen removal efficiency is a crucial indicator for the performance evaluation in slightly polluted river water treatment. Therefore, current study aimed to investigate the N removal efficiency of 3-stage surface flow constructed wetlands for water treatment. Results show that after a prolonged operation period, constructed wetlands were able to remove NH4+-N, NO3--N, and TN by 38.4%, 22.3%, and 29.1%, respectively. Further investigations were carried out to investigate the removal efficiency of various N species in the 3-stage wetlands. Findings reveal that NH4+-N was mainly treated in wetland #1 (W1) and wetland #2 (W2), while NO3--N and TN were in wetland #2 (W2) and wetland #3 (W3). Results also reveal that the influencing factors such as hydraulic retention time (HRT), water temperature (WT), and additional carbon source have significant effect on the removal performance of constructed wetlands.
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Affiliation(s)
- Dingbing Wei
- School of Civil Engineering, Southeast University, Nanjing, China
- Southeast University - Monash University Joint Research Centre for Future Cities, Nanjing, China
| | - Rajendra Prasad Singh
- School of Civil Engineering, Southeast University, Nanjing, China
- Southeast University - Monash University Joint Research Centre for Future Cities, Nanjing, China
| | - Yangke Li
- School of Civil Engineering, Southeast University, Nanjing, China
- Southeast University - Monash University Joint Research Centre for Future Cities, Nanjing, China
| | - Dafang Fu
- School of Civil Engineering, Southeast University, Nanjing, China.
- Southeast University - Monash University Joint Research Centre for Future Cities, Nanjing, China.
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Yu G, Tan M, Chong Y, Long X. Spatial Variation of Phosphorous Retention Capacity in Subsurface Flow Constructed Wetlands: Effect of Wetland Type and Inflow Loading. PLoS One 2015. [PMID: 26218872 PMCID: PMC4517764 DOI: 10.1371/journal.pone.0134010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
For verification of spatial distribution of phosphorous retention capacity in constructed wetlands systems(CWs), two horizontal subsurface flow(HSSF) CWs and two vertical subsurface flow(VSSF) CWs, using sand as substrate and Typha latifolia as wetland plants, were constructed and put into use for synthetic wastewater treatment. Five months later, significant spatial variations of TP and inorganic phosphorus(Ca-P, Fe-P and Al-P) were observed, which were found to be greatly affected by CWs type and hydraulic loading. The results revealed that though spatial distribution of Fe-P and Al-P displayed a similar order of substrate content as "rhizosphere" > "near-rhizosphere" > "non-rhizosphere" and "inflow section" > "outflow section" regardless of types and loading, the distribution of Ca-P was positively correlated to that of Fe-P and Al-P in HSSF CWs, while negative correlation was shown in VSSF CWs. As a result, TP spatial distribution in HSSF CWs demonstrated a greater dissimilarity than that in VSSF CWs. For HSSF CWs with low hydraulic loading, the lowest TP content was found in non-rhizosphere substrate of outflow section, while the highest one was discovered in rhizonsphere substrate of inflow section. The values in 6 parts of areas ranged from 0.138 g·kg-1 to 2.710 g·kg-1, which also were from -33.5% to 1209% compared to the control value. On contrast, spatial difference of TP content in substrates of VSSF CWs was insignificant, with a variation ranging from 0.776 g·kg-1 to 1.080 g·kg-1, that was 275% to 421% higher than the control value. In addition, when hydraulic loading was increased, TP content in VSSF CWs sharply decreased, ranging from 0.210 g·kg-1 to 0.634 g·kg-1. Meanwhile, dissimilarity of TP spatial distribution in HSSF CWs was reduced, with TP content ranging from 0.258 g·kg-1 to 2.237 g·kg-1. The results suggested that P spatial distribution should be taken into account for CWs design and operation.
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Affiliation(s)
- Guangwei Yu
- Department of Environmental Science and Engineering, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Meijuan Tan
- Department of Environmental Science and Engineering, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Yunxiao Chong
- Department of Environmental Science and Engineering, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, China
- * E-mail:
| | - Xinxian Long
- Department of Environmental Science and Engineering, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, 510642, China
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Kim B, Gautier M, Olvera Palma G, Molle P, Michel P, Gourdon R. Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2015; 71:1088-1096. [PMID: 25860713 DOI: 10.2166/wst.2015.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.
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Affiliation(s)
- B Kim
- University of Lyon, INSA of Lyon, LGCIE DEEP Team, 20 av. A. Einstein, 69621 Villeurbanne cedex, France E-mail: ; SCIRPE, 5 Allée Alban Vistel, 69110 Sainte-Foy-Lès-Lyon, France
| | - M Gautier
- University of Lyon, INSA of Lyon, LGCIE DEEP Team, 20 av. A. Einstein, 69621 Villeurbanne cedex, France E-mail:
| | - G Olvera Palma
- University of Lyon, INSA of Lyon, LGCIE DEEP Team, 20 av. A. Einstein, 69621 Villeurbanne cedex, France E-mail:
| | - P Molle
- IRSTEA, Wastewater Treatment Team, 5 rue de la Doua-CS70077, 69626 Villeurbanne cedex, France
| | - P Michel
- SCIRPE, 5 Allée Alban Vistel, 69110 Sainte-Foy-Lès-Lyon, France
| | - R Gourdon
- University of Lyon, INSA of Lyon, LGCIE DEEP Team, 20 av. A. Einstein, 69621 Villeurbanne cedex, France E-mail:
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Castaldelli G, Soana E, Racchetti E, Pierobon E, Mastrocicco M, Tesini E, Fano EA, Bartoli M. Nitrogen budget in a lowland coastal area within the Po River basin (northern Italy): multiple evidences of equilibrium between sources and internal sinks. ENVIRONMENTAL MANAGEMENT 2013; 52:567-580. [PMID: 23640695 DOI: 10.1007/s00267-013-0052-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 04/07/2013] [Indexed: 06/02/2023]
Abstract
Detailed studies on pollutants genesis, path and transformation are needed in agricultural catchments facing coastal areas. Here, loss of nutrients should be minimized in order to protect valuable aquatic ecosystems from eutrophication phenomena. A soil system N budget was calculated for a lowland coastal area, the Po di Volano basin (Po River Delta, Northern Italy), characterized by extremely flat topography and fine soil texture and bordering a network of lagoon ecosystems. Main features of this area are the scarce relevance of livestock farming, the intense agriculture, mainly sustained by chemical fertilizers, and the developed network of artificial canals with long water residence time. Average nitrogen input exceeds output terms by ~60 kg N ha(-1) year(-1), a relatively small amount if compared to sub-basins of the same hydrological system. Analysis of dissolved inorganic nitrogen in groundwater suggests limited vertical loss and no accumulation of this element, while a nitrogen mass balance in surface waters indicates a net and significant removal within the watershed. Our data provide multiple evidences of efficient control of the nitrogen excess in this geographical area and we speculate that denitrification in soil and in the secondary drainage system performs this ecosystemic function. Additionally, the significant difference between nitrogen input and nitrogen output loads associated to the irrigation system, which is fed by the N-rich Po River, suggests that this basin metabolizes part of the nitrogen excess produced upstream. The traditionally absent livestock farming practices and consequent low use of manure as fertilizer pose the risk of excess soil mineralization and progressive loss of denitrification capacity in this area.
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Affiliation(s)
- Giuseppe Castaldelli
- Department of Life Sciences and Biotechnology, University of Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy.
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