The Effect Of Magnetic Field On Chlorella Pyrenoidsa And Scenedesmus Obliquus Cultured By Urban Sewage

Using urban sewage as medium to cultivate high-lipid microalgae can onone hand achieve the purpose of the production of bio-diesel. on the other hand,purify waste water and achieve its resource utilization. Among this, increasingthe biomass and the fat yield of microalgae is an important part to reduce the cost.This paper aims to increase the biomass and fat yield of the Chlorellapyrenoidosa and Scenedesmus obliquus by the magnetic field.The algae species for this study are Chlorella pyrenoidosa and Scenedesmusobliquus. Firstly the urban sewage should be magnetized, and then use the urbansewage pre-treatment to cultivate the algae, lastly the algae solution is treated bythe magnetic field everyday. We can get the optimum magnetic treatmentconditions for the maximum fat content of Chlorella pyrenoidosa andScenedesmus obliquus, explore the mechanism of the magnetic field onmicroalgae, finally further validate the best condition of the magnetic field onalgae in the outdoor experiments.In the optimization process for the best magnetic conditons of Chlorellapyrenoidosa and Scenedesmus obliquus, the major influencing factors of thepre-magnetic for urban sewage and the daily magnetic for algae solutionv aremagnetic treatments, magnetized intensity and magnetized time. By single factorexperiments and orthogonal experiments, the final best magnetized conditions ofChlorella pyrenoidosa are as follows: the urban sewage is magnetized by5000GSstatic magnetic field for one hour, and then the algae solution is magnetized by5000GS dynamic cycle magnetic field for three hours. the final best magnetizedconditions of Scenedesmus obliquus are: the urban sewage is magnetized by1000GS static magnetic field for half an hour, and then the algae solution ismagnetized by1000GS dynamic cycle magnetic field for three hours.Through the effect of the magnetic on the urban sewage, it can be found thatthe magnetic field can increase the light through rate of urban sewage, reduce theCOD, enhance nitrification, promote the growth of bacteria in sewage and thebalance of algae and symbiosis. By the antioxidant capacity measurements ofChlorella pyrenoidosa and Scenedesmus obliquus, it can be found that theantioxidant capacity of Chlorella pyrenoidosa is higher than Scenedesmusobliquus, this explains why the Chlorella pyrenodiosa is more suitable for high-strength magnetic field. High-strength magnrtic can produce reactive oxygen,reduce the antioxidant capacity of Chlorella pyrenoidosa and make the proportion of C=O in microalgae increased.To further verify the growth promoting of the magnetic field on Chlorellapyrenoidosa and Scenedesmus obliquus, establish a columnar photobioreactor tocultivate algae, the results of orthogonal experimental are verified, after magnetictreatment the production of Chlorella algae increased by12.34%, fat productionincreased10.12%, the production of Scenedesmus obliquus algae increased10.21%, the fat production increase8.92%. At last in an example of Chlorellapyrenoidosa, explore the industrialization and determine the update rate of thecolumnar photobioreactor with the magnetic is25%.