The Process Analysis And Evaluation Of Water Pollutant Degradation By Enhanced Ecological Floating Bed In River System

This research focused on the application of ecological floating bed mainly consisting of plants and biological membrane in water purification.Since the existence of refractory organics and high concentration of nitrogen and COD,ceramsite,freshwater mussels and aerobic denitrifier were added to enhance the degradation.Based on correlation analysis of components and the whole floating bed system,the key functional components were identified.Aiming at the issues of incomplete Nitrogen degradation,after comparison and analysis of each component's contribution to the purification,a research on the enhancement of degradation was proposed and conducted.In this study ecological floating bed had shown good removing effect.After 5 days removal,concentration of NH4+-N,TP,COD changed from 25mg/L,2mg/L,80mg/L to 10mg/L,1.5mg/L,10mg/L.UV254 in characterization of humic type of refractory organic matter was effectively removed.In detail,the removal efficiency in five days reached around 60 percent.In this dissertation,Removal Contribution Ratio(RCR)and Degradation Contribution Ratio(DCR)are defined to represent the enhancement of contribution level.Ceramsite had obvious enhancement effect in removal of NH4+-N and UV254,in five days,the highest values of RCR for NH4+-N removal in plant floating bed and biological membrane floating bed systems were calculated as 49%%and 52.6%respectively,while in basic floating bed system it made modest improvement(6.2%only).For UV254 removal,RCR of plant and basic systems were 40%and 30%respectively.For N03-N and TP removal,ceramsite had a small improvement;for NO 3-N degradation,DCR of all types of floating beds were within the range of 8 to 15 percent,and for TP it was less than 10%.Aerobic denitrifier strengthened nitrate degradation to a large extent.In five days,its DCR could up to 27.3%and 20.5%for plant and biological membrane systems accordingly,while for basic floating bed system its enhancement was not obvious.In terms of total phosphorous and UV254,it showed weaker effect.Specifically,DCR for TP removal was less than 10/%and RCR for UV254 was around 10%in all floating bed systems.So ceramsite could be used to enhance the degradation of NH4+-N and humic acid.Experimental results showed that RCR of biological membrane was 30%to 40%for NH4-N,which was greater than that of plant(20%);for UV254,RCR of biological membrane could reach 62.6%when plant showed rare contribution;for NO3-N,the highest DCR of biological membrane in 5 days was monitored as 34.7%,which was much more than that of plant;for TP,DCR of biological membrane was 9.1%while for plant it was only 3.6%.Correlation coefficient of plant floating bed and basic floating bed is defined as RP2,and that of biological membrane floating bed and basic floating bed is RB2.In terms of NH4+-N,total nitrogen,TP and UV254,the value of RP2 is less than that of RB2;while in terms of NO3-N RP2 is greater than RB2.It proved that biological membrane was the functional component of purification,but plant dominated the accumulation of NO3--N.In addition,as the accumulation of NO3--N in continuous aeration floating bed system,intermittent aeration and aerobic denitrifying bacteria membrane floating bed could be adopted.After 7 days degradation by aerobic denitrifying bacteria membrane floating bed,concentration of NO3--N changed from 20mg/L to 0 mg/L.So floating bed attaching aerobic denitrifying bacteria membrane could be used to enhance nitrate degradation.