Design methodology accounting for the effects of porous medium heterogeneity on hydraulic residence time and biodegradation in horizontal subsurface flow constructed wetlands

Brovelli, Alessandro; Carranza-Díaz, Otoniel; Rossi, Luca; Barry, David Andrew

doi:10.1016/j.ecoleng.2010.04.031

Cited by 36 publications

(25 citation statements)

References 95 publications

(92 reference statements)

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“…Skewness reflects the symmetry of distribution; the values less than 0 mean the most data are lower than the mean. For a standardized normal distribution, the value of skewness is zero (Antonio et al, 2013;Brovelli et al, 2011). In the present study, the skewness values were near zero (Table 1).…”

Section: Descriptive Statistical Analysissupporting

confidence: 59%

Applying geostatistics to determine the soil quality improvement by Jerusalem artichoke in coastal saline zone

Long

Zhao

Liu

et al. 2014

Ecological Engineering

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a b s t r a c tThe plant growth characteristics are spatially variable due to inherent variability in soil properties and other parameters of the landscape. In the study, the plot size in the field was 670 m in length (south-north direction), and 70 m in width. The stem height and diameter were measured in October, and tuber yield was evaluated in December 2012. The salt content of 0-5, 5-10 and 10-20 cm depth of soil was measured. The morphological characteristics and normal distribution test were analyzed by descriptive statistics using Matlab. The collaborative kriging interpolation and the distribution of spatial heterogeneity of related parameters were analyzed using GS+ software. Soil salt content increased with increasing soil depth. At the same soil depth, the salt content was higher in the north than the south part. The root fresh weights, tuber number, stem height and diameter of Jerusalem artichoke were relatively larger in the north than the south. The distributions of tuber fresh weight and tuber number in space were similar. The Pearson correlation coefficient between tuber fresh weight and tuber number was up to 0.70. Jerusalem artichoke's morphological characteristics were directly related to soil salt content. Inherent variability of position and soil properties could strongly influence the morphological characteristics of Jerusalem artichoke.

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Section: Descriptive Statistical Analysissupporting

confidence: 59%

Applying geostatistics to determine the soil quality improvement by Jerusalem artichoke in coastal saline zone

Long

Zhao

Liu

et al. 2014

Ecological Engineering

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“…During water sampling, the ORP and temperature were measured in situ using a HANNA HI9828 multiparameter portable meter. The sample was then analyzed immediately in the laboratory for COD, NH 4 + -N, and TP by using standard methods (APHA, 1995). During the tracer tests, the wetlands were set a nominal hydraulic retention time (HRT) of 12 h. Tracer tests were conducted in each wetland for two sampling campaigns, January 2013 and September 2013 (absence and presence of growing vegetation, respectively), to analyze the hydraulic behavior of the CWs with different substrate configurations.…”

Section: Water Sampling and Measurementmentioning

confidence: 99%

“…The analysis was performed with SPSS.21 (SPSS-Boston, MA, USA: International Business Machines Corp, 2012). The isogram maps of COD, NH 4 + -N, TP, and ORP data were created using MATLAB 7.0 (MathWorks, Natick, MA, USA) to identify data trends within the CWs.…”

Section: Statistical Analysesmentioning

confidence: 99%

“…In recent years, CW design has evolved to mitigate the adverse effects of clogging [4,7]. Previous studies aimed at increasing hydraulic retention time and maximizing contact opportunity between the substrate and wastewater to improve treatment performance [8].…”

Section: Introductionmentioning

confidence: 99%

“…However, poor hydrodynamic behavior due to clogging is commonly found in full-scale CWs and have resulted in preferential flow pathways and dead zones [3]. Clogging may cause a large proportion of the water to pass over the bed as surface runoff, thus significantly reducing the effective volume of the system for removing waste [4]. The resulting ineffective wetland bed leads to incomplete biodegradation and reduces the performance of CWs [5,6].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multilayer Substrate Configuration Enhances Removal Efficiency of Pollutants in Constructed Wetlands

Bai

Ding

et al. 2016

Water

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Abstract:This study aimed at optimizing horizontal subsurface flow constructed wetlands (CWs) to improve hydraulic performance and pollutant removal efficiency. A groundwater modeling package (MODFLOW) was used to optimize three design parameters (length-to-width ratio, inlet/outlet-to-length ratio, and substrate size configuration). Using the optimized parameters, three pilot-scale CWs were built to treat actual wastewater. For model validation, we used a tracer test to evaluate hydraulic performance, and investigated the pollutant spatial distributions and removal efficiencies. We conclude that MODFLOW is suitable for designing CWs, accurately predicting that increasing hydraulic conductivity from surface to bottom layers could improve performance. However, the effect of vegetation, which decreased the hydraulic conductivity of the surface layer, should be considered to improve simulation results. Multilayer substrate configuration, with increasing hydraulic conductivity from the surface to bottom layers, significantly increased pollutant removal compared with monolayer configuration. The spatial variation in pollutant transport and degradation through the filling substrate showed that the multilayer configuration was able to increase use of the available space and moderately reduced short-circuiting and dead zones. Thus, multilayer CWs had higher experimental retention times, effective volume fractions and hydraulic efficiencies, and lower short-circuiting compared with monolayer CWs operating under similar conditions.

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Modelling groundwater residence time in a sub‐irrigated buffer zone

Mastrocicco

Boz²,

Colombani

et al. 2013

Ecohydrology

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This study focuses on the short groundwater residence time induced by the development of a dense rooting system in a forested area employed as a buffer zone planned for nitrogen removal. The buffer zone consists of a rectangular area of 0 center dot 7ha sub-irrigated by two ditches and drained by an outflow ditch lying in the centre of the area. The pristine soil (silty clay loam) was characterized by a low hydraulic conductivity, but the agricultural practice first, and then the rooting system increased the permeability of the top soil. This was confirmed by the elevated discharge in the outflow ditch and by the elevated hydraulic conductivity values determined via slug tests. The groundwater residence time was monitored, once the rooting system was completely developed, via Rhodamine-WT injection in the inflow ditch. The breakthrough curves were simulated using a one-dimensional analytical model (CXTFIT) to calculate the residence time. In addition, a three-dimensional flow and transport model (MODFLOW and MT3DMS) was calibrated using piezometric heads, groundwater fluxes and Rhodamine-WT concentrations. The CXTFIT model overestimated the dispersivity and underestimated velocity respect to MT3DMS. This study shows that residence time can decrease respect to the value expected from the hydraulic conductivities of the pristine soils and that one-dimensional analytical models can give a false impression compared with soil parameters respect to three-dimensional flow and transport models. Given the importance of the residence time for biological processes in buffer zones, a greater effort is needed to improve measurement techniques on subsurface flow's heterogeneity. Copyright (c) 2013 John Wiley & Sons, Ltd

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Design methodology accounting for the effects of porous medium heterogeneity on hydraulic residence time and biodegradation in horizontal subsurface flow constructed wetlands

Cited by 36 publications

References 95 publications

Applying geostatistics to determine the soil quality improvement by Jerusalem artichoke in coastal saline zone

Applying geostatistics to determine the soil quality improvement by Jerusalem artichoke in coastal saline zone

Multilayer Substrate Configuration Enhances Removal Efficiency of Pollutants in Constructed Wetlands

Modelling groundwater residence time in a sub‐irrigated buffer zone

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