The UROP Project I did this summer from late May to early August was maintaining two bioreactors (a vessel in which chemical or biological processes are carried out with organisms) containing one with granule algae and the other one with bacteria as denitrifiers. In the algae bioreactor, photosynthesis by granule algae in the aerobic environment was the most important process, and it also fixes carbon, which can be used as the electron donor. In the non-algae bioreactor, denitrification was the significant process, which used organic carbon as electron donor in anaerobic (low-oxygen) condition. The hypothesis of this study is that algae and denitrifying bacteria can co-exist in granular sludge, which can be used for nitrogen and phosphorus removal. My objective of this project was to maintain two bioreactors by collecting different kinds of data to prove that they were steady and worked well individually, and to test removing efficiency of each bioreactor with synthetic agricultural runoff water containing known amounts of nitrogen and phosphorus. If both bioreactors can work well individually, they can be combined together to develop algae-denitrifiers granules in a bioreactor setting in the future, which can be used to simultaneously reduce nitrogen and phosphorus. The result of this project was that both bioreactors were proved to be in a steady condition but the efficiency of nitrogen and phosphorus removing rates was not ideal, which was under our expectation that nitrogen and phosphorus can be removed steadily and effectively.