A microbial fuel cell (MFC) is a new technology for converting the chemical energy stored in the chemical bonds in organic compounds into electricity through the catalytic reactions by microorganisms. So, MFC is regarded as an ideal method for wastewater treatment and electricity generation simultaneously. A typical MFC consists of two chambers (anodic and cathodic) which are separated by a proton exchange membrane (PEM). The oxidation of organic compounds in anodic chamber yields electrons, protons and several by-products such as volatile fatty acids, biomass, and carbon dioxide. Absorbed electrons by anode are transferred to the cathode via external circuit, at this time protons pass through permeable membrane to the cathode. As a result, reaction of electrons, protons and oxygen takes place and produces water. Elimination of cathodic compartment creates a simpler design named single chamber microbial fuel cell in which cathode is exposed to air directly. Type of substrate is one of the most important parameters affects the amount of power and the efficiency of the cell. Wide range of substrates can be used in MFCs from pure compounds like acetate to complex organic mixtures like wastewater. Dairy based wastewater is rich in different types of organic and biodegradable compounds with high COD, so it is proper for being used as a fuel in MFCs. Considering the fact that about 2.5 times of the volume of the milk processed, is generated as wastewater and wastewater has 9.3 times more energy than treatment consumes, dairy wastewater can be beneficially used for biorenewable energy generation. Although, electricity generation or in the other words power production is considered as an important parameter, in this research treatment of dairy wastewater by annular single chamber microbial cell in continuous mode is the main objective. Since, this configuration (ASCMFC) has high power density and a successful performance in wastewater treatment in batch mode, it is selected for our experiments.