Study On Treatment Of Yujia Lake Water By Combined Phoslock And Algae Biofilm

Eutrophication has become one of the common environmental problems in the world.With the rapid development of city urbanization and industrialization,large amounts of untreated industrial,agricultural and domestic sewage directly discharged into the lake,causing a large number of domestic lake eutrophication problems,while phosphorus is considered to be the key factor for Lake eutrophication.In the self-made reactor,Phoslock was used to treat water of Yujia Lake,then carried out on the experimental study on removal of nitrogen and phosphorus in Yujia Lake by combined Phoslock with the algal biofilm.The main experimental conclusions were as follows.(1)The effect of phosphorus removal and regeneration of Phoslock were studied.Results indicated that the experimental equilibrium data were fitted better by using the Langmuir model Freundlich model,suggesting that the adsorption feature be monolayer.Meanwhile,the kinetic results can be fitted by the pseudo-second-order model,which indicated that the adsorption of Phoslock on phosphorus is chemical adsorption;In addition,the experimental study on the adsorption of Phoslock showed that it had a wide range of adaptation to pH,and it could get a good effect of phosphorus removal when pH was in the range of 3-9,but it was more favorable for phosphorus removal under the condition of partial acid;the regeneration experiment of Phoslock showed that it had a better regeneration effect in NaOH solution,after four times of adsorption-desorption cycles,the desorption rate of Phoslock could still up to 71%.(2)The treatment effect of lake water was studied using Phoslock in self-made simulation reactor.The removal rate of total phosphorus and orthophosphate by Phoslock could reach to 50% and 92% respectively,and the removal rate of COD could reach more than 40%,In addition,Phoslock also played a corresponding role in improving dissolved oxygen in water.The study on Phoslock adding method showed that there was no obvious difference between one-time dosing and batch dosing in the phosphorus removal effect.(3)The mixed culture biofilm was prepared by using Chlorella vulgaris and Scenedesmus obliquus.The method of adding biofilm after adding Phoslock had a better nitrogen and phosphorus removal effect,and the removal efficiency of total phosphorus,orthophosphate,total nitrogen and ammonia nitrogen in water was 93%,96%,91% and 90% respectively.In addition,both dosing method can significantly improve the dissolved oxygen concentration in water and decrease the content of COD,Comprehensive comparison,Phoslock was added to the water before adding algal film had more advantages in the management of eutrophication of the lake.