Study Of The Combination Technology Of Ecological Bag And Ecological Floating Island To Purify Polluted Water

Currently,the rural water environment in our country is not in an optimistic situation,with the stereoplasm of the revetment and the eutrophication of the water destroying the ecological environment of river system.Based on the view of restoration for rural polluted water,this paper compared the effects of phosphorus removal from egg shells,oyster shells,shellfish shells and ceramsite and selected the optimal material and the best dosage of it.What’s more,this project on the basis of eco-bags’revetment technology used biomass resources（rice straw,ect.）as a microbes load.And oyster shells were used as an adsorbent of ecological bags to enhance phosphorus removal rate.Therefore,a new ecological bag revetment,which is suitable for protecting rural environment,was put forward.At the same time,a new type of ecological floating island with a food chain about aquatic plants,aquatic animals and microorganisms and a three-dimensional partition structure was designed,and oyster shells were used for phosphorus adsorption,whose function of pollutants removal was improved.Two set of experimental study of a combination technology between ecological bag and ecological floating island were carried out to purify polluted water in the laboratory and at the Chenhaiwei Wetland Park and Jiandong Village.The achievements of this paper are as follows:（1）The research of phosphorus material showed that the adsorbent played a decisive role in the removal of phosphorus pollution among the particle size,the phosphorus concentration,the addition amount and the adsorbent.The ideal choice of the adsorbent was oyster shell.And the optimum addition amount of oyster shell is 50 g/L.Therefore,oyster shell was selected to enhance the effect of phosphorus removal of the ecological bag.（2）The operation test of ecological bag revetment,which added some biomass resources in order to strengthen the denitrification effect of nitrogen,indicated that ecological bag with biomass resources has a better purification effect than blank,also ecological bag with rice straw has the best purification effect,which is more suitable for nitrogen removal.In the stable period,the average removal rates of COD,TN,NH₄⁺-N,TP in biomass group were7.5%,8.2%,8.5%and 6.7%,higher than blank.And the average removal rates of rice straw of COD,TN,NH₄⁺-N,TP were 63.8%,82.7%,78.4%and 65.1%.（3）The results of microbial high throughput sequencing of different attached carrier ecological bags showed that the Chao1 of rice straw group,sponge gourd group and corn cob group increased by 13.9%,10.2%and 20.2%,indicating that the carrier system was more beneficial to pullutant removal.At the level of the genera,Pseudomonas,Azoarcus were detected in four ecological bags,which were useful for removing nitrogen pollution.Additionally,the cluster analysis of the horizontal samples showed that the dominant strains of rice straw was Nitrospirae.Nitrospirae was contributor to remove TN,NH₄⁺-N,which fits the experiment result that ecological bag with rice straw has a better purification effect on TN,NH₄⁺-N.（4）The effect of the ecological floating island for the removal of pollutants was obviously better than that of the ordinary floating island.And microbes were enriched by artificial fiber,which contributed to water purification.The operation experiment of ecological floating island and traditional floating island demonstrated that in stable period,the new ecological floating island had better removal efficiency for pollutants,compared with ordinary floating island,the average removal rates of COD,TP,TN and NH₄⁺-N were improved by 15.6%,13.2%,8.5%and 14.4%.The study of artificial fiber,which was packed in the ecological floating island,showed that Proteobacteria was the dominant phylum,which is good for pollutants removal.And Paracoccus and Hydrogenophaga in genera are aerobic denitrifying bacteria,which is beneficial to the removal of pollutants by ecological floating island.（5）The combination technology of ecological bag and ecological floating island has achieved a good purification effect in laboratory and demonstration.The results showed that the average removal rates of COD,TP,TN and NH₄⁺-N were 71.4%,64.3%,73.3%and71.4%with this combination technology during the operation time.During the pilot period,the water quality of Chenhaiwei water park was improved as a whole,from the surface poor V class water to the V class water standard.Also,The water quality of Jiandong village is improved obviously,the concentration of ammonia nitrogen has been under the class II level.The construction of demonstration projects accumulated relative experience about how to transform bank slope and purify waste water.The combination of these technologies provided a reference for the management of water environment,which has a good prospect in application.