The major advantages of mass cultured microalgae having over conventional aerobic wastewater treatment systems are reduced cost due to the decrease in energy input, low initial capital cost, and low operational cost (Wong and Tam, 1998). However, there are also lot disadvantages, e.g., microalgae cultivation is the space requirement. Since microalgae rely on photosynthesis, the availability of sunlight to reach the microalgae is critical. Therefore, microalgae-based wastewater treatment systems should be performed in low land-cost areas where sunlight and warm temperatures. The potential microalgal wastewater process was shown as the simplified process flow diagram envisioned for typical wastewater treatment, algal wastewater treatment with flue gas mitigation and production of various algal biomass products. The integrated process of using wastewater for microalgae production can be shown as the flow diagram envisioned for typical wastewater treatment, microalgal wastewater treatment with flue gas mitigation, and production of various algal biomass products. The typical wastewater treatment can be simply organized into three steps of solid–liquid separation, horizontal anaerobic fermentation and an activated sludge process in aerobic treatment. After the three-step wastewater treatment, the biochemical oxygen demand (BOD) and suspended solids (SS) of treated wastewater were both markedly reduced (Su et al., 1997). The effluent contains nitrogen, phosphorus and other nutrients, and the flue gas consists CO2, both provide the nutrition, including nitrogen, phosphorus and carbon sources, for the cultivation of microalgae. The integrated system of microalgal wastewater treatment incorporated with flue gas was using wastewater and flue gas process; that is not only an environmental-friendly but also a sustainable process for wastewater treatment and CO2 mitigation