Algal-bacteria symbiosis system is a promising wastewater treatment technology through the interactive supply of O2 and CO2 to reduce the aeration energy and CO2 emission. However, this innovation technology is hindered by limitations in field-scale application. One problem is that the implementation of existing algal-bacteria technology in urban areas is not practical because of the vast area needed for slower algae growth. Another problem is that algae suspended in the wastewater hinder photosynthesis efficiency. To address these shortcomings, this study has developed a vertical rotating algal-bacterial biofilm device, powered by a sunlight enhancement system, for purifying municipal wastewater. It has several practical advantages, including high photosynthesis efficiency, reduced land area requirement, low energy consumption, excellent nutrient utilization and minimal CO2 emission.