Application Research Of Hydroponic Plant Purification Bed System For Deep Treatment Nitrogen And Phosphorus

Now,the standard of effluent from municipal sewage treatment plants is enhancing.The concentration of nitrogen and phosphorus for many sewage treatment plants can not meet the relevant standards.Deep treatment nitrogen and phosphorus from the effluent is necessary.In this paper,taking the effluent from the two stage biochemical treatment facility as an object,the removal efficiency of TN and TP in sewage by using different hydroponic plant systems at different seasons was studied.The research showed that the average removal rate of TN in summer and autumn was 82.55%,which was the highest for hydroponic rice system.The daily absolute removal of TN in winter was 3904.2 mg/d,which was the highest for the hydroponic pakchoi system.The average removal rate and the daily absolute removal of TP in summer and autumn were the highest for the hydroponic rice system,which were 73.55%and 275.2 mg/d,respectively.The removal efficiency of TN in winter and spring for indoor hydroponic celery system was better than that of outdoor hydroponic celery system,while the removal effect on TP was opposite.The study on the contribution rate of the TN and TP removal in the first stage for the five stage hydroponic rice system showed that the microorganism and other effects was larger than that of the plant absorption,and both of them were greater than that of the precipitation.Under four kinds of HRT conditions in summer and autumn,the removal efficiency of TN and TP in four sets hydroponic rice systems showed that during the hydroponic culture of 63 d,the removal rate of TN and TP in sewage was the highest when HRT was 4.0 h.When HRT was shorter,the removal rate of TN and TP was lower in sewage system.Under four kinds of planting densities in autumn and winter,for four sets hydroponic reineckeac carne systems,the order of the removal efficiency of TN and TP from the most to the least is 3#system(three plants per hole)>2#system(two plants per hole)>4#system(four plants per hole)>1#system(one plant per hole).In Sichuan region,water spinach in autumn,pakchoi in winter,celery in winter and spring,rice in summer and autumn,reineckea carne in autumn and winter are all suitable for growth under hydroponic conditions.water spinach in autumn,pakchoi in winter,celery in winter and spring,rice in summer and autumn are suitable for hydroponic culture,which are used for deep treatment nitrogen and phosphorus of the two grade biochemical effluent.Due to the limited removal of TN and TP,reineckea carne in autumn and winter is just suitable for landscape improvement.