Nature Environment and Pollution Technology

Changjun Zhu ¹, Wenlong Hao ¹, Xiangping Chang ¹

Affiliations
1 College of Urban Construction, Hebei University of Engineering, Handan, Hebei, CN

Abstract

Instream vegetation not only affects the discharge capacity of the river but also plays an important role in the pollutants diffusion. So it is very important to study the pollutants diffusion in the open channels with vegetation. In order to experimentally investigate the effects of rigid vegetation on the characteristics of flow, the vegetation was modelled by a rigid cylindrical rod. The flow field is measured under the conditions of submerged rigid rod in a flume with single layer and double layer vegetation. Experiments were performed for various spacing of the rigid rods. The vegetation models were aligned with the approaching flow in a rectangular channel. Vertical distribution of pollutants was evaluated using image processing methods. The results indicate that the vegetation has a more stable effect on the spread of pollutants.

Keywords

Open Channel, Instream Vegetation, Pollutant Diffusion, Longitudinal Dispersion.

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Changjun Zhu ¹, Xiangping Chang ¹, Ming Liu ¹, Wenlong Hao ¹

Affiliations
1 College of Urban Construction, Hebei University of Engineering, Handan 056038, CN

Abstract

According to the characteristics of river sediment having greater impact on COD values, simulation experiment was used to explore the impact of sediment concentrations on COD, revealing the relationship between COD values and sediment. The level of sediment concentration has a more significant effect on COD degradation; higher the sediment concentration is, the greater is the rate of COD degradation. Sediment particle size also affects the rate of degradation of COD in water. With smaller particle size the rate of COD degradation is increased. This is because with the smaller particle size, the surface area is large, which in aqueous phase contaminants make it easier to achieve COD degradation.

Keywords

COD, Sediment Concentration, River Water, Sediment Particle Size.

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Changjun Zhu ¹, Wenlong Hao ¹

Affiliations
1 College of Urban Construction, Hebei University of Engineering, Handan, 056038, CN

Abstract

Recently, the construction of ecological civilization has been paid more and more attention. The construction of ecological river offers a new effective and ecological environmental method for river management and planning. Riparian vegetation can conserve soil and water and purify water quality. It also has a good repair for the ecological system. However, vegetation will recede the watercourse's capability of flood discharge. So, it is more important to study the effect of vegetation on flow characteristics. On the base of the former study, the localization is summarized, and the direction of future is drawn.

Keywords

Contaminant Transportation, Ecological Civilization, Ecological Watercourse, Vegetated Open Channel.

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Changjun Zhu ¹, Wenlong Hao ²

Affiliations
1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, CN
2 College of Urban Construction, Hebei University of Engineering, Handan 056038, CN

Abstract

Based on the grey theory, grey characters of river environment system were analyzed. The velocity and dispersion coefficient and attenuation in river were considered as uncertainty parameters and expressed as grey parameters. A grey differential equation of contaminant diffusion in river was built. And the equation has special structure. The truncation error of finite differential method in solving the model was corrected. According to the model, distribution values of pollutant concentration under sudden pollutant discharge can be obtained directly, which can provide abundant and useful water quality information for the plan and control of water pollution. It is shown that the calculated results obtained from the grey model are reliable and reasonable.

Keywords

River Water Pollution, Grey Parameters, Water Quality Simulation, Truncation Error, Grey Model.

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Changjun Zhu ¹, Ming Liu ¹, Wenlong Hao ¹

Affiliations
1 College of Urban Construction, Hebei University of Engineering, 056038 Handan, CN

Abstract

In view of near-ground atmospheric problem, near-ground atmospheric pollution model was established. Because the applicability of analytical solutions is extremely limited for such conditions, and the distribution and transport of pollutants in air are controlled by geographical conditions, numerical techniques are essential for air pollution modelling. In this paper, finite differential method is used to establish plane two-dimensional numerical model of near-ground atmospheric pollution belt, and truncation errors associated with finitedifference solution of atmospheric pollution were corrected based on the Taylor analysis. The results indicate that this method provides the references for the forecast of pollutants and the management and evaluation of air resources.

Keywords

Air Pollution, Finite Difference, Truncation Error.

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