Abstract: The design and operation of 338.58 kWp photovoltaic power generation system in a small sewage treatment plant is introduced. The photovoltaic module of the distributed photovoltaic power generation system is erected above the active sand filter,chlorine dioxide disinfection tank and hydrolysis acidification tank. Since the grid connected power generation on December 17,2021,the operation has been stable,and the actual daily average power generation capacity is 965.37 kW•h,higher than the predicted daily average power generation capacity（871 kW•h）. Compared with thermal power with the same power generation capacity,it is estimated that about 2 861 tons of standard coal can be saved and 7 620 tons of carbon dioxide can be reduced accumulatively in 25 years. The estimated annual income of the project is 296 500 yuan and the static payback period is 5.83 years. The installation of photovoltaic power generation system not only meets the power supply of the sewage treatment plant during the peak period of power consumption,but also controls the massive reproduction of algae to a certain extent,which has good economic and environmental benefits.

Key words: sewage treatment, distributed photovoltaic power generation, saving energy and reducing consumption