Effects of Rainfall and Vegetation Conditions on Colloid Transport in Saturated Vegetative Filter Strips

2020 ◽  
Author(s):  
Congrong Yu ◽  
Yufeng Sun
Keyword(s):  
Surface Water ◽  
Point Source ◽  
Removal Efficiency ◽  
Rainfall Intensity ◽  
Colloid Transport ◽  
Removal Mechanism ◽  
Point Source Pollution ◽  
Vegetative Filter Strips ◽  
Filter Strips ◽  
Non Point Source Pollution

<p>Non-point source pollution has become the main pollution source of surface water , among which colloidal pollutants are a kind of important non-point source pollutants. Rainfall runoff is the main factor that causes non-point source pollutants to migrate to water. Vegetative filter strips is an effective measure to control non-point source pollution. Vegetative density is one of the important factors affecting pollutant removal efficiency. In order to clarify the removal efficiency of colloidal non-point source pollutants by vegetative filter strips with different densities under rainfall conditions, it is necessary to study the effects of vegetative density and rainfall intensity on the migration and removal mechanism of colloids in vegetative filter strips. Based on the numerical model established by coupling non-Darcy flow water balance equation and colloid transport equation, combined with laboratory experiments and numerical simulation, the removal mechanism of colloid at different migration distances was studied under the conditions of fixed inflow, different rainfall intensity and vegetative density.</p><p>The results show that: 1) Although there is no infiltration, the colloid diffuses from surface water into saturated sand, which increases the removal efficiency of colloid. 2) Increasing vegetative density will increase the removal efficiency of colloids in vegetative filter strips. With the increase of density, the velocity of flow decreases, which decreases the deposition capacity of colloids on vegetative and increases the diffusion of colloids from surface water to soil. 3) Under rainfall conditions, the presence of rainfall increases the removal efficiency of colloids by vegetative filter strips. Although rainfall weakens the ability of vegetative to deposit colloids, it enhances the ability of colloids to diffuse to soil. The deposition capacity of colloids on vegetative increased with the increase of rainfall intensity. 4) The interception ability of vegetative enhances the diffusion ability of colloids to soil, and enhances the removal efficiency of colloids by vegetative. 5) In the vegetative filter strips, the adsorption coefficient of colloids decreases with the migration distance, mainly due to the heterogeneity of colloids. In the process of colloid migration, the absolute value of surface potential and the colloid with smaller particle size along the course are easy to be removed by vegetative filter strips because of the smaller barrier between colloid and plant, the smaller second energy potential well and the strong adsorption capacity of colloid deposition.</p><p>The research results provide important theoretical basis and reference for designing vegetative filter strips to remove colloidal non-point source pollutants under rainfall conditions.</p>

Pesticide contamination of water resources: a case study - the rivers in the Paris region

1996 ◽  
Vol 34 (7-8) ◽  
pp. 147-152 ◽  
Author(s):  
M. A. Tisseau ◽  
N. Fauchon ◽  
J. Cavard ◽  
T. Vandevelde
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Point Source ◽  
Pesticide Contamination ◽  
Point Source Pollution ◽  
Run Off ◽  
Catchment Areas ◽  
Paris Area ◽  
Three Rivers ◽  
Non Point Source Pollution

For a number of years, the Compagnie Générale des Eaux has been studying pesticide contamination of surface water in order to better understand the origins and the main transfer mechanisms of these pollutants into water resources. Sampling campaigns are being carried out on the three main rivers of the Paris area to monitor a number of products from the triazine and urea families. This monitoring has confirmed the extension of agricultural non-point source pollution. The products being sought are present in the three rivers and, in most cases, in significant concentrations. Atrazine is the most important contaminant. Measured concentrations exceed the value of 100 ng/l most of the time, thus proving that the aquifers drained by the three rivers are contaminated. For a period of several months every year, concentrations approaching 1000 ng/l are observed in all the catchment areas being studied. These are the result of rapid transfers of atrazine in run-off water. This surface run-off transfer mode also seems to be applicable to the ureas found in surface water, especially during the periods when the products are used to treat crops. These works underline the complexity of agricultural non-point source pollution phenomena. They permit the identification of the predominant mechanisms operating in the transfer of the products. This is the first step towards setting up preventive measures and developing pollution forecasting tools.

scholarly journals Impacts of drought on the quality of surface water of the basin

2013 ◽  
Vol 10 (11) ◽  
pp. 14463-14493
Author(s):  
B. B. Huang ◽  
D. H. Yan ◽  
H. Wang ◽  
B. F. Cheng ◽  
X. H. Cui
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Point Source ◽  
Surface Water Quality ◽  
Point Sources ◽  
Point Source Pollution ◽  
Drought And Flood ◽  
The Impact ◽  
Non Point Source Pollution

Abstract. Under the background of climate change and human's activities, there has been presenting an increase both in the frequency of droughts and the range of their impacts. Droughts may give rise to a series of resources, environmental and ecological effects, i.e. water shortage, water quality deterioration as well as the decrease in the diversity of aquatic organisms. This paper, above all, identifies the impact mechanism of drought on the surface water quality of the basin, and then systematically studies the laws of generation, transfer, transformation and degradation of pollutants during the drought, finding out that the alternating droughts and floods stage is the critical period during which the surface water quality is affected. Secondly, through employing indoor orthogonality experiments, serving drought degree, rainfall intensity and rainfall duration as the main elements and designing various scenario models, the study inspects the effects of various factors on the nitrogen loss in soil as well as the loss of non-point sources pollution and the leaching rate of nitrogen under the different alternating scenarios of drought and flood. It comes to the conclusion that the various factors and the loss of non-point source pollution are positively correlated, and under the alternating scenarios of drought and flood, there is an exacerbation in the loss of ammonium nitrogen and nitrate nitrogen in soil, which generates the transfer and transformation mechanisms of non-point source pollution from a micro level. Finally, by employing the data of Nenjiang river basin, the paper assesses the impacts of drought on the surface water quality from a macro level.

Application of Media Manufactural by Waste Plastic to Stormwater Treatment in Urban Drainage System

2006 ◽  
Vol 510-511 ◽  
pp. 606-609 ◽  
Author(s):  
Seog Ku Kim ◽  
Sang Leen Yun ◽  
Young Im Kim ◽  
Sung Won Kang ◽  
Yong Jae Lee
Keyword(s):  
Point Source ◽  
Removal Efficiency ◽  
Water Permeability ◽  
Rainfall Intensity ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Point Sources ◽  
The Other ◽  
Road Runoff ◽  
Point Source Pollution

While more attention has been paid in recent years to urban point source pollution control, no considerable measures have been taken to control urban non-point source pollution. Contaminants from non-point sources deposited on urban impermeable surfaces such as road and highway are easily released to the public waters by rainfall, leading to the deterioration in water quality in urban area. Experiments were performed using a reactor and real rainwater runoff obtained from road surfaces at various pollutant loading and rainfall intensity to determine the criteria for the first flush rainwater and to evaluate the applicability of the reactor for treating road runoff. The results at different rainfall intensities show that the medium PPB is superior to the other media for water permeability. PPB was not blocked at 10 mm/hr rainfall, and its permeability was stable. On the other hand, PVS and PPF resulted in a substantial overflow ratio even at 1 mm/hr rainfall intensity. Comparison of treatment efficiencies for suspended solids showed that all media showed similar removal efficiency ranging from 91% to 95%. However, PPB seems to be better than the other media considering its higher water permeability. PPB and PPF, both hydrophobic, yielded over 76% of heavy metal removal. But the hydrophilic media PVS showed much smaller removal efficiency ranging from 26% to 47%. The treatment efficiencies over PAHs (Poly Aromatic Hydrocarbons) showed the similar removal efficiency ranging from 66% to 97% for all three media. In this study a reactor using filter media was investigated to reduce the level of contamination in urban road runoff.

A Modeling Approach for Evaluating Watershed-scale Water Quality Benefits of Vegetative Filter Strip - A Case Study in Ontario

2019 ◽  
Vol 35 (3) ◽  
pp. 271-281 ◽  
Author(s):  
Anand Krishna Gupta ◽  
Ramesh Pal Rudra ◽  
Bahram Gharabaghi ◽  
Pradeep Kumar Goel ◽  
Saleh Sebti ◽  
...  
Keyword(s):  
Point Source ◽  
Watershed Scale ◽  
Point Source Pollution ◽  
Vegetative Filter Strips ◽  
Filter Strip ◽  
Vegetative Filter Strip ◽  
Modeling Approach ◽  
Sediment Loads ◽  
Non Point Source Pollution

Abstract. Vegetative filter strips (VFS) are globally recognized as an effective BMP in reducing non-point source pollution. Maximum effectiveness of a VFS at a watershed-level could be achieved by adequately installing and sizing a VFS along the edge of the field. Existing watershed models have limitations in appropriately representing and modeling VFS at the watershed scale. Therefore, in this research, a new modeling approach consisting of the Agricultural Non-Point Source (AGNPS) model, AGNPS_VFS toolkit, and a regression equation is developed to explore the effectiveness of VFS applied along the edge of fields. AGNPS cells are identified as locations where the edge of the field VFS is to be installed. Further, the approach was tested with a case study. The model was calibrated and validated for a flow and sediment load at the watershed outlet. Thereafter, the modeling approach is used to compute sediment reducing efficiency (SRE) for the edge of the field VFS. Objectives of this study were to test the effectiveness of uniform VFS (5 × 18 m) lengths located at several locations (draining an upstream area of 3, 4, 6 ha, and at spatially variable locations) within a watershed to demonstrate the ability of the developed approach to evaluate effectiveness of VFS application in sediment abatement. Maximum SRE was observed for VFS placed at spatially variable locations; the developed approach reduced nearly 23.03% of sediment yield, while VFS placed along cells draining an upstream area of 3, 4, and 6 ha removed 9.59%, 12.39%, and 5.91% of sediment loads respectively. Keywords: Non-point source pollution, Sediment transport, Vegetative filter strip (VFS), VFSMOD.

scholarly journals Characteristics of Non-Point Source Pollution under Different Land Use Types

2020 ◽  
Vol 12 (5) ◽  
pp. 2012 ◽  
Author(s):  
Jun Yang ◽  
Jiping Liang ◽  
Gaihe Yang ◽  
Yongzhong Feng ◽  
Guangxin Ren ◽  
...  
Keyword(s):  
Land Use ◽  
Point Source ◽  
Rainfall Intensity ◽  
Phosphorus Content ◽  
Dry Season ◽  
Water Bodies ◽  
Point Source Pollution ◽  
Nitrogen And Phosphorus ◽  
Land Use Types ◽  
Non Point Source Pollution

Non-point source pollution (NPSP) is a major challenge for current global water resources. The output characteristics of pollutants under different land use types are very important for controlling NPSP. In this study, long-term positioning monitoring and an analysis of rainfall runoff from different land use types were used to evaluate a typical watershed in the water source area of the middle route of the South-to-North Water Diversion Project (MR-SNWDP). The results show significant differences in nitrogen and phosphorus content in the runoff water bodies of various land use types. The nitrogen and phosphorus content in the MR-SNWDP was directly related to rainfall intensity and the fertilization period in the runoff following fertilization of farmland and vegetable plots. This nitrogen and phosphorus content was also observed to be significantly higher in the fertilization period than in other periods. The loss of nitrogen and phosphorus in forestland was greatly affected by rainfall intensity. Nitrogen in runoff comes primarily from farmland and vegetable fields, where its main form is nitrate nitrogen (NN). Vegetable fields are the main source of phosphorus, where its primary form is soluble phosphate (PO43−-P). Nitrogen and phosphorus have a defined incubation period during the dry season. Farmland and vegetable fields receive less rainfall during the dry season and it is difficult to form effective runoff; this allows nitrogen and phosphorus deposition. The runoff formed by the first rainfall at the beginning of the flood season (April or May) will carry a large amount of nitrogen and phosphorus from the soil into water bodies. Therefore, it is crucial to pay careful attention to the season when attempting to control NPSP.

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