Application Of Artificial Aquatic Plants In Brackish Water Purification And Its Mechanism Study

Brackish water is between the salt water and fresh water, usually found in river estuary, the salinity is between 0.5-30,water remediation technology commonly used are often not suitable for contaminative brackish water. According to the high salinity of contaminative brackish water and the big problem of water quality improvement, the process and the law of purification of the ultrafine stereo fiber artificial plants method has been researched, the growth rhythm, activity, metabolic characteristics and diversity of the microbe on artificial plants has been analyzed to reveal the mechanism of the artificial plants purification.Determination for the microbial quantity by using DAPI method, the microbial activity was determined by FDA method, using Biolog technology and 454 high-through put sequencing method to analyze microbial speciesdiversity and metabolic diversity.The results showed that the use of artificial plants will not be restricted by temperature, salinity and light, and the removal rate of permanganate index, ammonia nitrogen and turbidity reaches to 17.90%-57.75%,39.19%～73.95% and 36.74%～60.07% respectively. As the artificial plants are kept in the water, the number of microbes on the surface of artificial plants will gradually increase(up to 9.23x107/g) and the activity will be growing. The number and growth rate of activity of microbes have a remarkable correlation with the removal rate of TP, ammonia nitrogen and turbidity. The metabolism characteristics of microbes on the surface of artificial plants which are put into water in different time were analyzed by Biolog-Eco Technology. The results show that, with time goes by, the microbial metabolic activity(expressed as AWCD value)has a process of first increasing and then decreasing, and the analysis of the single factor variance of AWCD value shows that the use of carbon source by microbes has a significant difference(F=9.42> F0.05(4,39)=2.64). The relative utilization rate of six kinds of carbon source by microbes from high to low is respectively carbohydrate metabolism community, polymer community metabolism, amino acids metabolism, metabolic community carboxylic acids, phenolic acids, amines. Microbial diversity index of Shannon, Simpson, Mclntosh have a process of first increasing and then decreasing. A total of 454 high-throughput sequencing using to extract the 221,830 high-quality sequences,36 phyla,105 classes,202 orders,312 families,480 genera were detected in biological membrane on the surface of artificial plants using 454 high-throughput sequencing method, thus microbial species are very rich. The dominant bacteria are different at the phylum, class, order, family, genus level in different times, but overall, the dominant bacteria proportion is still higher than others;species richness reaches a maximum at tenth week; there is a difference between the third week and other weeks in abundance.May be due to external causes, such as weather or water exchange is more appropriate Proteobacteria reproduction, growth and reproduction of other species is limited. A large number of microorganisms are Proteobacteria,Cyanophyta, Bacteroides,Planctomycetes and Actinomycetes. Proteobacteria which is the removal of COD’s main actors.Water quality improved when the artificial plants were used in purification of brackish water. The study on the microbes in the microbial membrane on the surface of artificial plants also provides a theoretical basis for its application. The use of artificial plants is not restricted by temperature, high salinity, illumination condition, the materials are cheap and easy to obtain, furthermore, the materials itself will not cause pollution to the water body, and can be used repeatedly.