The Study Of The Remediation Of Europhicated Water And Control Of Algae By Duckweed

With the increasing eutrophication of the water body in our country, plankton bloom caused by cyanophytes broke out frequently. It would cause enormous loses in the national economy. Microcystis aeruginosa is the mainly common cyanophytes of plankton bloom in our country. The application of aquatic macrophytes in wastewater decontamination can not only remove the pollutant, but also harvest biomass. This technique combines wastewater treatments with source reuses and is an economical-efficient and easy-spreading option for the purification of wastewater. Duckweed is a kind of floating plant,with the trait of growing rapidly, being rich in protein, harvesting conveniently and with high removal rate of N and P.Duckweed and Microcystis aeruginosa was the investigated objective in this study. Under different nutritient and environmental condition, we studied the growth characteristic and the nutrient accumulation of duckweed. Also effects of duckweed on the growth of Microcystis aeruginosa were investigated. The results showed that:The two kinds of duckweed, Lemna minor and Sprrodela polyrhiza, can grow well in Steinberg medium, while the growth of duckweed was suppressed in Hutner medium. Lemna minor grew better than Sprrodela polyrhiza in both mediums.In Hutner medium with high ammomium concentration, Sprrodela polyrhiza began to lose root and turn yellow. As a result, we chose the Lemna minor as study objective.Through the study on the responses of macroscopical growth, physiological parameters and antioxidant enzymes to nutrient content in waterbody, results proved that ammonium was negative to Lemna minor growth which would be highly suppressed by over-high concentration (20mg/l). The cell of duckweed encountered seriously oxidative damage in high ammonia concentration, which can make photosynthesis decrease and cell dehydration. However, Lemna minor was less sensitive to phosphorus and even in high phosphate content duckweed could function regularly. The assimilation rate of Lemna minor on N and P in waterbody had positive correction with the concentration of N and P. While the...