Research On The Effect Of Improved Artificial Wetland System For Tailwater Treatment Of Simulated Wastewater Treatment Plant

After the sewage is processed in the wastewater treatment plant,most of the pollutants in the effluent can be removed.However,even if the effluent can meet the national Class I B standard for pollutant discharge of municipal wastewater treatment plants（GB18918-2002）,the wastewater The concentration of pollutants in the environment is still far beyond the Environmental Quality Standards for Surface Water（GB3838-2002）.Wastewater from wastewater plants cannot be directly reused,and emissions to the environment can cause water pollution in different degrees.This experiment is intended to improve some of the inadequacies of traditional constructed wetland technology.The improved artificial wetland system is utilized to treat the tail water of the wastewater treatment plant to study the removal effect of pollutants in the sewage.The experiments mainly improve the matrix and denitrification performance in constructed wetland systems.The matrix is Fully mixed with bio-char and activated carbon with strong adsorption performance in the ratio of 1:10.Then the mixed matrix is Filled into the vertical flow constructed wetland system to monitor the effect of the mixed matrix on the removal of pollutants from the tail water.The biochar used in this experiment was done in the bamboo straw.The denitrification performance was improved by the artificial introduction of heterotrophic denitrifying bacteria.The denitrification capacity of the constructed wetland system was confined to the denitrification of the system.One of the main factors of efficiency,this study introduced heterotrophic denitrifying bacteria into the system during the initial stage of system operation,and utilized sodium acetate as an electron donor to study the effect of removing pollutants from the system.Heterotrophic denitrifying bacteria were of Sludge enriched culture.During the experiment,three gradient hydraulic loads（0.25 m³/（m²·d）,0.5 m³/（m²·d）,and 1 m³/（m²·d））and three electronic supply-to-loss ratios（1.5:1,2:1,and 2.5:1）Impact on the system’s ability to remove contaminants.The test run results are as follows:（1）The use of bio-char and activated carbon as substrates for adding to the constructed wetland system can comprehensively improve the system’s removal efficiency of various pollutants,in which the removal rate of NH₄⁺-N in the wastewater is increased by about 7%,and NO₃^--N The removal rate increased by about 5%,the removal rate of TN increased by about 7%,the removal rate of TP increased by about 11%,and the removal rate of COD increased by about 13%.（2）The addition of heterotrophic denitrifiers in the system had no obvious effect on the removal of pollutants.The removal rate of NH₄⁺-N in the wastewater increased by 2%.However,the removal effect of NO₃^--N on the system was compromised.The removal rate decreased by 0.37%.From the overall operation of the system,the wetland system had a slight increase in the removal of nitrogen from the sewage,the removal rate of TN increased by about4%,and heterotrophic denitrifying bacteria were in addition to the system.The removal of phosphorus in sewage has a sizable increase,the removal rate of TP is increased by about4%,the removal effect of COD is not improved obviously,and the removal rate increases by about 4%.（3）The removal effect of NH₄⁺-N in sewage by three sets of wetland systems is best at intermediate hydraulic load.The removal rate of the hydraulic load at 0.5m³/（m²·d）is higher than the hydraulic load of 0.25m³/（m²·d）and 1m³/（m²·d）.The removal rate of NO₃^--N is gradually increased.Overall,the removal efficiency of nitrogen in the three systems is best when the hydraulic load is 0.25 m³/（m²·d）.The removal effect of COD has a tendency to increase first and then decrease with the increase of the hydraulic load.When the hydraulic load is 0.5m³/（m²·d）,the removal rate is the highest.The removal rate of phosphorus is greater than the hydraulic load of 0.25m³/（m²·d）and 0.5m³/（m²·d）when the hydraulic load is 1m³/（m²·d）,but between different hydraulic loads.In comparison,the removal rates are not significantly different.（4）The removal effect of NH₄⁺-N by the system is inclined to decrease first and then increase.NO₃^--N is the highest when the supply-demand electronic ratio is 2.5:1,and the removal of TN is increased first.Reduce.The removal effect of COD is progressively increased.The removal rate is best when the ratio of supply and loss is 2.5:1.The removal effect of TP is best when the ratio of supply to call for is 2.5:1.（5）According to the correlation analysis of temperature and pollutant removal rate,there is a significant positive correlation between nitrate nitrogen removal rate and temperature（P<0.05）,No.2 system’s removal rate and temperature of total phosphorus.There was a significant positive correlation（p<0.05）,and the removal efficiency of pollutants and the significance of temperature were not significant in other systems.