Process Research For Cultivation Of Lipid-rich Microalgae Using Municipal Wastewater In Photobioreactor

Using urban sewage as medium to cultivate high-lipid microalgae can on theone hand achieve the purpose of the production of bio-diesel. on the other hand,purify the waste water, to achieve its resource utilization. Among this,developing a process with large-scale application prospects and optimizing itscorresponding operating conditions is essential. This paper is intended to designa set of continuous operation process in column bioreactor to achieve outdoorhigh concentration of microalgae culture, to provide a steady stream of rawmaterials for the preparation of bio-diesel, and efforts resorted to up-to-standardrelease of water quality index such as nitrogen, phosphorus and other waterquality indicators.Learn through literature review and our research group preliminary work,screening the algae species suitable for outdoor sewage training, sewagepretreatment were dicussed. When using actual sewage to culture microalgaeoutdoors, scenedesmus obliquus shows better growth stability and higher lipidyield than chlorella pyrenoidosa. And the relative abundance of scenedesmusobliquus can reach93.4%, with strong competitive advantage, more suitable foroutdoor sewage culture. After primary sedimentation, the sewage can directly beused for Scenedesmus obliquus outdoor cultivation without autoclaving orsonication treatment.The factors which can affect outdoor sewage cultivation of microalgae wereoptimized, including light, mix, carbon dioxide enrichment, magnetism andcultivating mode. The smaller the column diameter, the higher the lipidproduction of Scenedesmus obliquus. And for column photo-bioreactor with largediameter, fiber can be to some extent, improve the internal light conditions,thereby enhancing the production of algae lipid production. Mixing and magnetictreatment can to some extent improve the Scenedesmus obliquus lipid production.When cultivated with2%carbon dioxide enrichment, Scenedesmus obliquusreach the maximum lipid production which is2.5times that of the control group.A set of semicontinuous operation process in column bioreactor to achieveoutdoor high concentration of scenedesmus obliquus lipid production was built.By using the culture conditions: aeration0.2vvm,1%CO₂enrichment, the50mTcircular magnetic treatment, combined with fiber, mirrors, light shading as lightadjustment measures, the update rate of20%of the semi-continuous culture, andcultured in8L columnar photobioreactor, the maximum lipid production of scenedesmus obliquus is0.15g/L, and the effluent NH₄⁺-N, TN, TP, COD reachesemission standards.