Studies Of The Absorption To Various Pollutant Of Large Wetland Plants In Aquaculture Wastewater With Various Salinity

As the population increases,the demand for aquatic products increases,and the density of aquaculture is growing significantly.It leads to aquaculture environmental degradation.The research on treating wastewater and purifying water quality by large aquatic plants has been paid more and more attention.In this study,first,enrichment of mineral elements and heavy metal of Canna indica,Iris tectorum,Thalia dealbata and Phragmites communis were harvested and determined,second,simulation experiment of circulating water system in greenhouse to study NP enrichment in large wetland plants.Finally,growth and purification of large wetland plants treated by salinity and aquaculture wastewater.Comprehensive understanding of the ability and characteristics of four plants in the purification of various types of aquaculture wastewater was explained in this study.The main results were showed as follows:1.In constructed wetlands,compared with I.Tectorum and T.Dealbata,C.indica and P.communis had stronger bioremediation capability.Each plant had strong nitrogen enrichment,and had different other element enrichment.C.Indica is especially rich in phosphorus,potassium,magnesium,zinc,copper and sodium,but I.Tectorum has strong ability to enrich phosphorus,calcium and magnesium,P.communis has strong ability to enrich sulfur,ferrum,aluminium,chromium,cadmium and plumbum;T.Dealbata has a stronger ability to enrich sulfur and manganese.2.In phytoremediation,the NP enrichment mainly accumulated in the shoot,in the course of the large wetland plants repairing eutrophic aquaculture water,it can be harvested through the shoot of the remove of the NP.When the three wetland plants were mixed in a certain proportion,the absorption of nitrogen in the mixed system increased and the absorption of phosphorus decreased.When different plants are mixed in a certain proportion,they will have different emphasis on the absorption of nitrogen and phosphorus.When the specific pollutants are treated,the plants will be mixed with the corresponding proportion to achieve better purification effect.3.Under salt stress,the growth of C.Indica had the most obvious response to salt stress,and the addition of the aquaculture wastewater has alleviated the damage of the salt;P.Communis has the most tolerant of salt stress.In the study of the ability of the nitrogen enrichment under salt stress,the nitrogen content of P.Communis and T.Dealbata was higher and the enrichment ability of nitrogen was stronger.The shoot of the I.Tectorum has the strong enrichment of phosphorus.The activity of SOD and POD in C.Indica was impressionable in salt stress and wastewater treatment;I.Tectorum and T.Dealbata had stronger antioxidant enzyme activities under high salt stress and wastewater treatment,and had partly tolerance to salt stress,and responded more significantly to high salt stress.P.Communis had little difference in antioxidant enzyme activity under different treatments,and had the strongest tolerance to salt stress and wastewater treatment.4.The different rhizosphere secretion of the four wetland plants lead to differences between the species and quantity of the rhizosphere microorganism Among the four wetland plants,the rhizosphere microbes of T.Dealbata were the most abundant and the species had the highest diversity,while the rhizosphere microbes of.Tectorum had the least species.Under different salt stress and wastewater treatment,the stable dominant species of rhizosphere microorganisms in P.Communis were the most,and the number of microorganisms remained stable at the root of I.Tectorum were least.The response of the microbial population with different purifying effect to the different salt stress and wastewater treatment had significant differences.