Study On The Efficiency Of Electrolytic-Enhanced Constructed Wetland In The Treatment Of Nitrogenous Wastewater

Nitrogen-containing wastewater comes from a wide range of sources,and its discharge increases year by year,so that its harm becomes increasingly prominent.Therefore,the effective treatment of nitrogenous wastewater has become one of the urgent and significant issues in the field of water treatment.However,the traditional nitrogen-containing wastewater treatment technology has some shortcomings and limitations,which limits its efficiency.As a mature ecological wastewater treatment technology,constructed wetland has been widely used in the treatment of all kinds of wastewater.Iron-carbon micro-electrolysis technology has become a new hot spot in the field of wastewater treatment due to its efficient processing effect.Therefore,this topic tries to combine iron carbon micro-electrolysis technology with constructed wetland to treat nitrogen-containing wastewater,adjust the optimal operating parameters,and design electrolytic enhanced constructed wetland for nitrogen-containing wastewater treatment.In this study,iron-carbon mass ratio（Fe/C）,wastewater pH value and initial influent concentration of ammonia nitrogen were selected as experimental factors.Orthogonal experiments were designed to determine the optimal combination of the optimal mass ratio of iron carbon filler,pH value of wastewater and initial concentration of ammonia nitrogen influent.The results show that the order of influence on the experiment in the constructed wetland is as follows:pH value of wastewater>mass ratio of iron to carbon>NH₄⁺-N influent concentration.Iron carbon micro electrolysis of constructed wetland,the optimal scheme of simulated nitrogen wastewater treatment is the pH value of 3 waste water,quality of the iron carbon ratio of 3:1,NH₄⁺-N concentration in the water for 25 mg·L^-1,under this combined condition,the removal rate of NH₄⁺-N in iron carbon micro electrolysis of constructed wetland can reach 90%.Canna indica,Iris wilsonii C.H.Wright,Acorus calamus and Cyperus involucratus were selected to study the effects of different wetland plants on the nitrogen treatment efficiency of iron-carbon micro-electrolytic constructed wetland.By analyzing the changes of NH₄⁺-N,TN,TP,COD and other pollutants in effluent water of different plant wetlands,it is found that Canna indica-iron carbon micro-electrolytic constructed wetland group has the best effect in treating simulated nitrogen-containing wastewater.The removal rates of NH₄⁺-N,TN,TP and COD are 73.36%,82.43%,99.96%and 85.44%,respectively.The effects of iron carbon micro-electrolysis system on wetland plant physiology and ecology were investigated.The results showed that the iron-carbon micro-electrolysis system had certain effects on the physiological ecology of the four plants.During the experimental period,all the four plants showed poor growth,yellow leaves withered and stopped germination of new roots.The relative content of chlorophyll decreased;decreased net photosynthetic rate,decreased conductance,and decreased transpiration rate in plants.The comprehensive application of electrolytic enhanced constructed wetland technology in river water quality improvement was introduced,taking the reconstruction project of Second Ring City Park（B1-B3）in Nanhui New City as an example.In order to maintain and improve the water quality of the river within the design range,the project adopted the measures of setting up the end treatment system including multistage biological filter,gravity flow wetland,curtain type and composite floating island wetland.The results show that COD,TN and TP removal capacity of the end treatment system is different.This project reflects that electrolytic enhanced constructed wetland technology has become a design method with both ecological and aesthetic effects in actual landscape planning projects,and has practical application value in enriching urban landscape and improving water quality.