Study on the Efficiency of Oxygenation and Phosphorus Removal in Urban Polluted Rivers by Oxygen Nano-bubble Modified Particles
Hypoxia is a key triger of continuous deterioration of water quality in urban polluted rivers.In this study,oxygen nanobubbles were loaded onto the surface of Bentonite,Attapulgite and Muscovite minerals by alcohol-water substitution method to develop oxygen nanobubble modified mineral materials(ONBMMs),and the oxygenation and phosphorus removal efficiencies of ONBMMs were tested in the simulated urban polluted water-sediment core system.The results showed that the dissolved oxygen at the sediment-water interface increased rapidly with the addition of ONBMMs,up to more than 7.0 mg/L,and the surface layer of the sediment was about 1.0 cm into an aerobic state.Compared with the control group,the total phosphorus in the overlying water of the experimental group decreased by more than 90％.The increase of dissolved oxygen at the sediment-water interface increased the redox potential of surface sediments,inhibited sulfate reduction and the formation of reduced S2-,and increased the retention ability of iron oxides to phosphate.16S rRNA analysis showed that the addition of ONBMMs inhibited the growth of Longilinea and Syntrophomonas in surface sediments,but promoted the enrichment of Thermomonas.The change of microbial community showed the improved living environment of benthic organism.The increase in the abundance of Acidovorax and Acinetobacter also reflected the role of nitrate-reducing ferrous oxidizing bacteria and phosphorus accumulating bacteria in the decrease of phosphorus during the oxygenation process.ONBMMs can rapidly improve the oxygen level at the sediment-water interface and effectively inhibit the release of sediment phosphorus,which has a good application prospect in the improvement of urban river water quality and in-situ control of endogenos pollution.
oxygen nanobubblessediment-water interfaceoxygenationphosphorus inhibitionurban polluted river
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