Effect of key design parameters on bacteria community and effluent pollutant concentrations in constructed wetlands using mathematical models

Sanchez-Ramos, David; Agulló, Núria; Samsó, Roger; García, Joan

doi:10.1016/j.scitotenv.2017.01.014

Cited by 28 publications

(4 citation statements)

References 35 publications

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“…The typical substrate depth of subsurface flow CWs is 0.5 m, but several authors have found that shallow constructed wetlands (SCWs) can improve the removal of nitrogen, organic matter [15,16] and estrogenic disruptors by a more efficient dissolved oxygen transfer to the media [17]. Additionally, a SCWs require fewer building materials, and consequently a lower cost of construction, operation and maintenance [18].…”

Section: Introductionmentioning

confidence: 99%

Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

et al. 2020

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In this study, pilot-scale hybrid constructed wetlands (CWs) and multistage horizontal subsurface flow CWs (HF CWs) have been studied and compared for the treatment of raw urban wastewater. In the hybrid CWs, the first stage was a mulch-based horizontal subsurface flow CW and the second stage was a vertical subsurface flow CW (VF CW). The VF CWs were used to determine if sand could improve the performance of the hybrid CW with respect to the mulch. In the multistage HFs, mulch, gravel and sand were used as substrates. The effect of water height (HF10: 10 cm vs. HF40: 40 cm) and surface loading rate (SLR: 12 vs. 24 g Chemical Oxygen Demand (COD)/m2d) has been studied. The results show that the use of sand in the vertical flow stage of the hybrid CW did not improve the average performance. Additionally, the sand became clogged, while the mulch did not. The effect of water height on average pollutant removal was not determined but HF10 performed better regarding compliance with legal regulations. With a SLR of 12 g COD/m2d, removals of HF10 were: 79% for COD, 75% for NH4+-N, 53% for dissolved molybdate-reactive phosphate-P (DRP), 99% for turbidity and 99.998% for E. coli and total coliforms. When SLR was doubled, removals decreased for NH4+-N: 49%, DRP: −20%, E coli and total coliforms: 99.5–99.9%, but not for COD (85%) and turbidity (99%). Considering the obtained results and the simplicity of the construction and operation of HFs, HF10 would be the most suitable choice for the treatment of raw urban wastewater without clogging problems.

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Section: Introductionmentioning

confidence: 99%

Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

et al. 2020

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“…This study showed that increased water depth may cause dispersion of the pollutants, lower the concentration gradient, and reduce the reaction rate. Sanchez-Ramos et al [29] found that shallow water allows a greater development of bacterial communities, which has an impact on the biochemical reactions triggering contaminant transformation and degradation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Water Depth and Phosphorus Availability on Nitrogen Removal in Agricultural Wetlands

Song

Ehde

Weisner

2019

Water

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Excess nitrogen (N) from agricultural runoff is a cause of pollution in aquatic ecosystems. Created free water surface (FWS) wetlands can be used as buffering systems to lower the impacts of nutrients from agricultural runoff. The purpose of this paper was to evaluate critical factors for N removal in FWS wetlands receiving high nitrate (NO 3 − ) loads from agriculture. The study was performed in 12 experimental FWS wetlands in southern Sweden, receiving drainage water from an agricultural field area. The effects of water depth (mean depth of 0.4 m and 0.6 m, respectively) and phosphorus (P) availability (with or without additional P load) were investigated from July to October. The experiment was performed in a two-way design, with three wetlands of each combination of depth and P availability. The effects of P availability on the removal of NO 3 − and total N were strongly significant, with higher absolute N removal rates per wetland area (g m −2 day −1 ) as well as temperature-adjusted first-order area-based removal rate coefficients (K at ) in wetlands with external P addition compared to wetlands with no addition. Further, higher N removal in deep compared to shallow wetlands was indicated by statistically significant differences in K at . The results show that low P availability may limit N removal in wetlands receiving agricultural drainage water. Furthermore, the results support that not only wetland area but also wetland volume may be important for N removal. The results have implications for the planning, location, and design of created wetlands in agricultural areas.

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“…The study on the abundance and spatial distribution of bacteria indicated that, under the stable condition of CW operation, the anaerobic bacteria dominated the CWs while the sulphate reducing bacteria, the dominant bacteria, accounted for 46%. The strong relationship between the temporal and spatial distribution of bacteria and the removal rates of pollutants has been observed [58]. According to the previous study [29], anaerobic processes contributed to almost 72%-79% removal rate of COD in HF CWs, which indicated that anaerobic bacteria, such as methanogens and sulfate reducers, play a main role in pollutants removal.…”

Section: Balance Of Prediction Results and Model Structurementioning

confidence: 86%

Numerical Models of Subsurface Flow Constructed Wetlands: Review and Future Development

et al. 2020

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Numerical model as a simulation tool was used to describe the pollutants transformation and degradation process in constructed wetlands (CWs). It can help provide insight into the “black box” and increase the understanding of the complex processes in CWs. In the last few decades, several process-based numerical models were developed to depict the pollutants removal processes in CWs, which include biochemical model, hydraulic model, reactive-transport model, plants model, clogging model, and coupling model combining two or more sub-models. However, there was a long way to go before fully understanding the decontamination mechanisms of CWs. On the one hand, single or a composite model coupling a small number of sub-models cannot fully reveal the decontamination processes. On the other hand, a comprehensive model including all sub-models of current cognition involves numerous parameters, most of which are interaction and cannot quantitatively determined, thus making the model complex and leading to diffuse interaction. Therefore, in order to describe the reaction processes in CWs more accurately, it is expected that all parameters should be quantified as far as possible in the future model. This study aims to provide a review of the numerical models of CWs and to reveal mechanism of decontamination. Based on the advantages and disadvantages of existing models, the study presented the improvement method and future research direction: (1) new detection/monitoring technique or computing method to quantitatively assess the parameters in CWs models, (2) correcting the simulation errors caused by the assumption of Activated Sludge Models (ASMs) and developing a complete biofilm reaction sub-model, (3) simplification of the comprehensive model, and (4) need of emerging pollutants modeling.

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Effect of key design parameters on bacteria community and effluent pollutant concentrations in constructed wetlands using mathematical models

Cited by 28 publications

References 35 publications

Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

Multistage Horizontal Subsurface Flow vs. Hybrid Constructed Wetlands for the Treatment of Raw Urban Wastewater

Effects of Water Depth and Phosphorus Availability on Nitrogen Removal in Agricultural Wetlands

Numerical Models of Subsurface Flow Constructed Wetlands: Review and Future Development

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