The Effect And Mechanism Of Coelastrella Sp. To Stress Of Cu(?) In Swine Wastewater Treatment

With the increase of biologic treatment technology,many studies tend to wastewater treatment by microorganisms?such as bacteria,microalgae,duckweed,etc.?.Microalgae could adapt various swine wastewater because of its special nature of cell;therefore,treatment of wastewater by microalgae gradually becomes recognized in today.Microalgae not only have strong adaptation and growth ability,and can store the starch and triacylglycerol which could produce ethanol and biodiesel.That is one of the reason why many scholars think microalgae biodiesel might become the third generation biological energy.Cu???were one of the essential micro element in many animal feeds.However,the absorption of Cu???by this animal was very low,and most of Cu???in feeds was excreted.For example,there only 10%-20%of Cu???was absorbed by pigs,and all of the others were be excreted,so there might a high Cu???concentration in swine wastewater,and effected the treatment ability of microalgae.Therefore,to provided the information for the swine wastewater treatment technology based on microalgae cultivation,in this study,the effects of Cu???on the growth of Coelastrella sp.might be result.And it also discussed about the physiological and biochemical properties and the production of biodiesel of Coelastrella sp.when stress of Cu???in swine wastewater.Coelastrella sp.could remove nutrient from swine wastewater,while the effect of Cu???which were input from animal feeds to its were not understood.In this paper,nutrients removal and physiological and biochemical properties of Coelastrella sp.were investigated at the presence of Cu???in swine wastewater.Results showed Cu???reduced the removal efficiency of ammonia and TP?total phosphorus?of Coelastrella sp.in swine wastewater.In the experiments,NH₃-N?ammonia nitrogen?has been reduced,the TP also decreased when Cu???concentration was not higher than 1.0 mg/L.When Cu???concentration higher than1.0 mg/L,the TP concentration stop decreased in 4 days.Microalgae growth was inhibited at all the Cu???concentrations,and the microalgae stopped grow when Cu???concentration not higher than 1.0 mg/L in about 6-8 days,and the removal ability of NH₃-N and TP were decrease and drop.With an increased Cu???concentration,the contents of chlorophyll a and proteins decreased,when the Cu???concentration was higher than 1.0 mg/L,the chlorophyll a decreased rapidly,and also decreased with a Cu???concentration decreased.When existed Cu???,the concentration of protein decreased 57.8-72.4%.When Cu???concentrations higher than 2.0 mg/L,the content of octadecanoic acid?18:0?and hexadecanoic acid?C16:0?and octadecenoic acid?C18:1?were increase,while octadecatrienoic acid?C18:3?gradually disappeared.At 0.5 mg/L of Cu???,TP removal efficiency maximized 84.9%,NH₃-N removal efficiency was 58.8%,and the biomass productivity and the tolerance to Cu???poison were optimal.