Study On Artificial Ecological Floating Bed Purification System Based On Electrochemical Technology

With the influence of human activities,the nutrient elements in water are increasing,which leads to the increasingly serious eutrophication of water,damages the balance of aquatic ecosystem,and brings serious harm to the health of human beings and aquatic organisms.Artificial ecological floating bed,as a new water restoration technology,can use plant roots to purify nitrogen and phosphorus in water.At the same time,it can also generate a large number of enzymes to accelerate the degradation of organic matter in water.In addition,iron-carbon microelectrolysis technology has attracted wide attention because of its efficient treatment of sewage.It uses the basic principle of metal corrosion to form galvanic cells,which are realized through the comprehensive effect of wastewater reduction,electrochemistry and adsorption of iron ions.In this study,an electrochemical artificial ecological floating bed system was constructed using iron carbon microelectrolysis technology.The optimal electrochemical substrate was selected by studying different iron-carbon mass ratios（1:1,2:1,3:1）and different total iron-carbon inputs（8 g/L,16 g/L,24g/L）,and then the single plant and mixed plant planting of four aquatic plants（canna,iris,yellow calamus,windmill grass）.To screen out the best single plant aquatic plants and mixed plant combinations.It provides theoretical basis for the"iron-carbon micro-electrolysis technology+artificial ecological floating bed"system to reduce nitrogen,phosphorus and ammonia nitrogen in eutrophic water bodies,and provides technical support for improving regional water environment and beautifying urban environment.The main results of this study are as follows:1)The application of electrochemical substrates on artificial ecological floating beds has shown good results in purifying TN,TP and NH₄⁺-N in water bodies,with significant differences compared to the group without electrochemical substrates.The results showed that the removal rate of TN could reach over 63%,which was 11.69%higher than that of the CK group;The removal rate of TP can reach over 84%,which is 20%higher than that of the CK group.The removal rate of NH₄⁺-N ranges from 53.65%to 67.08%.The experimental group with a iron carbon mass ratio of 1:1 and a total iron carbon input of 8 g/L had the best purification effect,with removal rates of 79%,93.83%,and 67.08%for TN,TP,and NH₄⁺-N in the water,respectively.2)The four plants selected for the experiment,single plant planting and mixed plant planting,coupled with iron carbon microelectrolysis,all have good purification effects on TN,TP,and NH₄⁺-N.Among the four plants,the best one for TN removal is the single plant plantain,which has a TN removal rate of 84.56%.The mixed planting group has the highest TN removal rate of 80.02%,which is better than the single plant planting of iris（74.92%）,calamus（74.69%）,and windmill（75.18%）,indicating that mixed planting has a certain promoting effect on TN removal rate.For the removal effect of TP,the single plant planting of Canna（97.14%）and Iris（92.06%）was superior to the mixed planting group of four plants（72.94%～89.13%）,indicating that the mixed planting of these four plants did not have an advantage in TP removal rate.For the removal effect of NH₄⁺-N,there was a significant difference between single plant cultivation of canna,iris,and mixed plant cultivation of iris+windmill grass and other experimental groups,with removal rates of 80.56%,76.98%,and 77.02%,respectively.However,there was no significant difference between the mixed planting groups of calamus,windmill,and other plants.Therefore,canna can be the best plant for single plant cultivation,and canna+calamus can be the best combination plant for mixed planting.3)In this study,the growth rate of SPAD values in the mixed planting group was better than that in the single plant planting group,especially in the single plant planting groups of Canna（-1.26%）and Iris（-7.04%）,which had a negative growth rate,showing a significant difference from the mixed planting group（-0.48%～32.24%）.There was no significant difference in the growth rate of single plant planting among the four plants.However,the comparison of growth rates between single plant planting and mixed planting of the four plants showed that the growth rate of single plant planting of Chinese and American banana（-7.07%）and iris（2.08%）was higher than that of the mixed planting group of American banana（-43.13%）and iris（-3.94%）,while the growth rate of single plant planting of yellow calamus（-19.75%）was lower than that of its mixed planting group（-11.76%）.In conclusion,the electrochemical artificial ecological floating bed system constructed by iron-carbon micro-electrolysis technology in this study can effectively purify eutrophic water bodies and has a high removal rate of pollutants.Further exploration can be carried out through more indicators and engineering practice projects in the future.