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Hao Wang ¹, Can Tian ¹, Huiyuan Zhong ¹, Xiaoqing An ¹, Bingxu Quan ¹

Affiliations
1 College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, 063009, CN

Abstract

In this study, the kinetic models of pollutant degradation in different wetlands were studied. The kinetic equations were deduced and the kinetic simulation of the main pollutants such as NH₃-N and TN was completed by the experimental data, and the dynamics of the pollutant degradation simulation model were applied to simulate the effect of the reaction kinetics model on the removal of contaminants in horizontal steel slag subsurface wetland (HSSSW) and horizontal volcanic subsurface wetland (HVSW). The results showed that the first order reaction kinetics model could obviously simulate the effect of main pollutants such as NH₃-N and TN in two kinds of subsurface wetlands. The correlation coefficient R² of the dynamic linear model was 0.9640 and 0.9600 in HSSSW, respectively, and the correlation coefficient R² of the HVSW was 0.9365 and 0.9709, respectively. The degree of fitting and correlation was very good. Besides, the simulation results showed that the degradation of the main pollutant was of great reference value for the design and operation of the practical subsurface wetland.

Keywords

Constructed Wetland, Nitrogen Degradation, Kinetic Models.

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Hao Wang ¹, Bingxu Quan ¹, Huiyuan Zhong ¹, Shan Yan ¹, Meiyuan Yang ¹

Affiliations
1 College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, 063009, CN

Abstract

In this research, electrochemical system was adapted to decompose lightly polluted wastewater (LPW). The major pollutants of LPW were removed and its removal effects were investigated. Meanwhile, courses of the electrochemical reaction for nitrogen and phosphorus were discussed. Experiments results exhibited that the best removal rates of NH₃-N and TN respectively were 100% and 90.9% after dosing NaCl. In addition, under the condition of different electrolysis time, removal of pollution was better than without NaCl, namely, the pollution was removed rapidly through electrolysis when other experimental conditions remained invariable. Meanwhile, the optimal operation condition could be confirmed while the current density was 7.4mA/cm², the cell voltage was 6 V, electrolysis time was 30 min, the plate distance was 1cm and the ratios of concentration of NH₄⁺ and Cl^- were 1:3, respectively. Besides, the removal effects for nitrogenous compounds as the change of the chloride concentration were investigated, too. And the results exhibited that higher the chloride concentration in the wastewater was, the higher the removal rate for nitrogenous compounds was. The removal rates of nitrogenous compounds increased with the increasing of cell voltage. Therefore, the influence of every factor could be obtained through considering the power consumption of per ton wastewater treatment.

Keywords

Electrochemical Method, Electrolysis Time, NaCl Dosing, Nitrogenous Matter.

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Hao Wang ¹, Huiyuan Zhong ¹, Lin Liu ¹, Bingxu Quan ¹

Affiliations
1 College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, 063009, CN

Abstract

In this research, electrocoagulation technology was used to treat high fluorine content geothermal water. The fluoride removal performance and operating costs have also been discussed. The results showed that electrocoagulation was an ideal technology to remove fluoride ions from geothermal water, and did not need to change the pH value and temperature of raw water. During the static experiments, for electrolysis time of 15 min, plates spacing of 0.5 cm, area of plates/volume of wastewater of 80 m²/m³, current density of 4.5 mA/cm² and no adjusted pH, the highest removal efficiency of fluorine from geothermal water was achieved. Under these operating conditions, the fluoride concentration of effluent water was 0.8 mg/L or so, which fully met the drinking water health standard (0.5 mg/L < F- < 1.0 mg/L). Meanwhile, the energy consumption was evaluated under various operating conditions. And it would be affected by some different parameters. Besides, dynamic experiments were carried out when optimum parameters were selected after static experiments. When the current density of 10 A/m², the system effluent fluoride concentration was about 1.4 mg/L, and the process did not meet the requirements, so current densities were adjusted to 12.5 A/m² and 15 A/m², while the effluent fluoride concentration was about 1.2 mg/L and 0.8 mg/L, respectively.

Keywords

Defluoridation, Fluorine, Electroflocculation, Geothermal Water.

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