scholarly journals Simulating the impact of piers on hydrodynamics and pollutant transport: A case study in the Middle Yangtze River

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260527
Author(s):  
Haibin Xiong ◽  
Li Chen ◽  
Zhaohua Sun ◽  
Zhiqing Li ◽  
Kun Zhou ◽  
...  

It is known that channel engineering, including the construction of piers, will change the river hydrodynamic characteristics, which is a significant factor affecting the transport process of pollutants. With this regard, this study uses the well-validated and tested hydrodynamic module and transport module of MIKE 21 to simulate the hydrodynamics and water quality under various pier densities in the Wuhan reach. Hydrodynamic changes around the piers show spatial differences, which are similar under different discharges. The range and amplitude of hydrodynamic spatial variations increase with the increase in pier density. However, there is a critical value of 1.25 to 2.5 units/km. When the pier density is less than this critical value, this type of cumulative effect is the most significant. Additionally, greater changes can be found in chemical oxygen demand concentrations, which also show spatial and temporal variations. The area with high chemical oxygen demand concentration upstream and downstream from the engineering area exhibits the distribution characteristics of “decrease in the downstream area and increase in the upstream area” and “increase in downstream the area and decrease in the upstream area” respectively. In the reach section of the engineering area, the area with high chemical oxygen demand concentration increases in the front area near the piers and decreases near the shoreline. Furthermore, the concentration shows attenuation actions with a longer residence time owing to the buffering effect of pier groups. These results have significant implications on shoreline planning and utilization. Moreover, they provide scientific guidelines for water management.

2018 ◽  
Vol 3 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Andras Jozsef Toth ◽  
Eniko Haaz ◽  
Botond Szilagyi ◽  
Tibor Nagy ◽  
Ariella Janka Tarjani ◽  
...  

Abstract Washing detergents in process wastewaters from fine chemical industry produce high Chemical Oxygen Demand (COD), which poses a serious environmental problem. Method has to be found, which follows the principles of circular economy so that the treated water can be recycled or reused. Heat pump vacuum evaporator is evaluated in order to reduce the Chemical Oxygen Demand of process wastewater with washing detergent content from initial 7500 mg O2/L to a lower value below the effluent limit , which is 1000 mg O2/L. Yield and COD rejection are determined for the evaluation of selected treatment. Experiments are investigated with LED Italia R150-v3 pilot apparatus. Different evaporation pressures were applied during measurements. It The highest removal or reduction of in the Chemical Oxygen Demand was reached certainly using the lowest possible pressure, which is 40 mbar.


2020 ◽  
Vol 32 (5) ◽  
pp. 2773-2783
Author(s):  
Julieta Lois-Milevicich ◽  
Nahuel Casá ◽  
Paola Alvarez ◽  
Ricardo Mateucci ◽  
Víctor Busto ◽  
...  

RSC Advances ◽  
2017 ◽  
Vol 7 (38) ◽  
pp. 23714-23726 ◽  
Author(s):  
Xin Zhou ◽  
Zeqian Zhang ◽  
Yaxin Li

Biokinetic models of high-strength coking wastewater with a high chemical oxygen demand (COD) was efficiently treated by a novel pilot-scale four-stage biofilm anaerobic–anoxic–oxic–oxic (FB-A2/O2) system.


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