NOVELTY - An elliptical fermentation treatment tank which performs fermentation in the linear portion of the tank. A partition placed between two tanks is positioned parallel to the peripheral partition of each tank. The tank corners enable compost to flow from one tank in a reverse direction mutually to the adjoining fermentation tank.    DETAILED DESCRIPTION - The fermentation treatment tank performs fermentation on livestock dung to form compost. On completion of the fermentation process, the compost advances in a reverse direction to the adjoining tank. Each fermentation treatment tank has three zones, an aeration and heating zone (3), a fermentation zone (4) and a maturing zone (5) arranged in a sequence. A warm air pipe (6) for heating and for supplying air to the tank is embedded under a piping groove provided at the floor surface of the treatment tank. A warm air generator (7) is provided to each zone. The quantity of warm air supplied and the temperature of the warm air are controlled by passing the air from the generator through an electrically driven control valve (11). A temperature sensor, an air quantity sensor attached to the medial wall surface of the partition wall of every zone detect the air temperature and air quantity and transmit the information to a computer for process control via a control program. The air supply quantity and air supply temperature to each process zone is controlled.    DESCRIPTION OF DRAWING(S) - The figure shows the entire top view of the livestock dung fermentation treatment tank. (1) Peripheral partition, (2) Inner side partition, (3) Aeration and heating zone, (4) Fermentation zone, (5) Maturing zone, (6) Warm air pipe, (8) Temperature sensor, (9) Air quality sensor, (10) Control computer, (13) Stirring machine, (14) Output channel. (MW)    USE -   For fermenting livestock dung generated in a hen house or a cattle shed to produce a compost or for fermenting activated sludges.    ADVANTAGE -   As the fermentation tank is ellipse shaped, the corners are smooth and hence removal of the compost from the corners is easy. There is no need to use stirring machines for compost removal. Therefore, the working rate of the treatment tank is improved and the operation efficiency is improved sharply. The flow of the fermentation process is simple as the compost from one tank flows in a reverse direction to the other tank to reach the aeration and heating zone of the other tank. Since the flow is easy and simple, a wide range of activated sludges other than livestock dung can be processed and hence the process is economical. Since the tank is divided into different process zones, the conditions in each process zone can be set as the optimum conditions corresponding to the processed material and hence the process is effective and economical.