Large area requirements and huge energy consumption restrict the applications of microalgae in wastewater treatment. In this study, in-situ nutrient removal was tested using a floating permeable nutrients uptake system with pore sizes of 1, 5, 10, and 40 µm, and Chlorella sorokiniana and Scenedesmus acuminatus. Results showed that N transfer rate across FPNUS varied with membrane pore size and N-type. Average transfer rate of NH4+-N, NO3--N, and NO2--N across 1 µm membrane was 2.6, 14.6, and 2.3 mg m-2h-1, respectively, sufficient to support microalgal growth. The NH4+-N and NO3--N removal rate in shrimp wastewater reached 1.32 and 1.88 mg L-1d-1, comparable to some BNR processes used in RAS. According to the developed area ratio prediction model, FPNUS to pond area ratio of 21% is sufficient to balance N loading of 0.05 mg L-1d-1. These results indicate extraordinary potential of in-situ nutrient removal from wastewaters using FPNUS.