| Groundwater pollution control is imminent,the traditional physical and chemical management of the existence of different degrees of limitations.Artificial wetland technology to purify polluted wastewater by domestic and foreign scholars unanimously approved,has many advantages.In addition,iris plants as a common aquatic plants on the purification of heavy metal contaminated wastewater has also been related to the validation of the researchers.In this paper,simulated wastewater with mixed groundwater(Fe?Mn?NO3-)was set up in the laboratory according to the relevant standards.Simulated wastewater was treated with iris planted wetland as control.The main research contents are:(1)Study on the removal efficiency of single heavy metal element iron and manganese in Iris plantation wetland;(2)Purification of iron,manganese and nitrate-nitrogen combined pollution wastewater by iris artificial wetland;(3)the variation of nitrogen and phosphorus in single and compound pollution state of Iris plantation wetland;(4)Study on the hydrodynamic characteristics of Acorus calamus constructed wetland.The results are as follows:(1)In the case of single contamination,the final effluent concentration of the reactor was less than 1.2 mg / L,and the removal rate was 95%.For the removal of manganese,the water concentration of the wetland system was 0.5mg / L-3.1mg / L,and the removal rate was87%.The effluent concentration of the plant was not between 4.2 mg / L and 9.7 mg / L,and the removal rate was 62%.With the increase of the degree of water pollution,the purification of iron and manganese in the reactor was not affected.After 9 days of operation,the purification effect was decreased compared with that at 4 days.In addition,the process of growth of calamus plants in good condition,iron-containing iris plant plants slightly higher than manganese-containing sewage.(2)The average effluent concentration of Fe3 + was 1.2 mg / L and the removal rate was97% in the three concentrations of compound pollution and in the experiment.When the concentration of influent pollution was low(Fe3 +: 15 mg / L;Mn2 +: 30 mg / L;NO3-: 20mg/ L): CWs of Iris plantation reached the peak after 9 days of continuous water intake.0.57mg/ L,the removal rate was 98.3%.With the increase of the concentration,the effect of Mn2 +on the wetland was decreased to a certain extent.In addition,the enrichment of iron and manganese in calamus plants was: medium concentration> low concentration> high concentration,underground part> aboveground part.(3)For the removal of nitrate nitrogen,the effluent concentration of plant wetland system was 0.03 mg / L,the removal rate was 93.2%,and the plant wetland was the concentration of7.85 mg / L and the removal rate was 19.1%.For the purification of nitrite nitrogen,the concentration of artificial wetland was 0.01 mg / L and the removal rate was 80.3%.The concentration of plant wetland was 0.03 mg / L and the removal rate was 41%.For the removal of ammonia nitrogen,the concentration of artificial wetland was 0.4mg / L and the removal rate was 85%.The effluent concentration of plant wetland was 0.74 mg / L and the removal rate was 48.5%.During the test,the purification of NO2-in medium and high pollution conditions showed saturation.(4)Through the tracer test,it is verified that the design of the constructed wetland and the method of matrix filling are reasonable.The effective volume ratio(e),short-circuit value(s),hydraulic efficiency ?(%)and recovery rate(%)of A.calamus constructed wetland were0.49,0.33,87.7% and 85.1% respectively;No plant wetlands.0.38,0.42,49.3% and 88.6%,respectively. |
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