Study On Purification Effect Of LED Red And Blue Combined With Gravel On Eutrophication Water Quality

In this thesis,using red and blue LED irradiation technology combined with glass gravel biological fillers,through indoor simulation tests and field pilot verification tests,the changes of water quality,phytoplankton,zooplankton,and microbial communities in eutrophic water were studied.The main results are as follows:The results of indoor simulation experiments show that under the action of red and blue LEDs,the dissolved oxygen concentration at the bottom of the water body is greatly increased to reach saturation;the total nitrogen concentration has been reduced by 40%,the COD concentration has been reduced by 40%,and the phosphorus release suppressed,and the types and numbers of phytoplankton and zooplankton in water have increased.In field experiments on eutrophic landscape lakes,the physical and chemical indicators of water quality,the types and numbers of phytoplankton and zooplankton,and the changes in microbial community structure were measured and analyzed.The results showed that compared with the control group,the treated group of red LED and blue LEDirradiated the dissolved oxygen concentration in the bottom of the water body increased by 90%,reaching the saturation level;the total nitrogen concentration was reduced by 60%,and the ammonia nitrogen and nitrate nitrogen concentrations were obtained control;COD concentration decreased by 30%.At the same time,the number of species of cyanobacteria decreased,the number of diatom species appeared and the number of proliferation increased significantly;the structure of the microbial community also increased significantly,increasing the growth activity of the microorganisms.From the results of high-throughput sequencing of the biofilm attached to the surface of the gravel biofilm filler,it was found that under the irradiation of red and blue LEDs,the number of polyphosphate bacteria and polysaccharide bacteria increased.Studies have shown that this type of microbial flora can promote the degradation of organic matter and denitrification.In addition,during the experiment,the independently developed experimental device operated stably with good results.The above research proves that this technology can improve the water quality of eutrophic water and increase biodiversity.