NOVELTY - The culture device comprises a production module in which microalgae are cultured, a module for biological dephosphatation of waste water, which is independent of the production module and produces a liquid effluent, and a module for physico-chemical retreatment of the liquid effluent originating from the biological dephosphatation module enabling the incorporation of the effluent into the production module. The production module comprises a strain of microalga that removes the inorganic nutrients contained in the effluent after physico-chemical retreatment.    USE - The device is useful for culturing microalgae for the production of biofuel.    ADVANTAGE - The device allows economically viable culture of microalgae without pollution or environmental degradation thus providing long-term production of biofuel.    DETAILED DESCRIPTION - The culture device comprises a production module in which microalgae are cultured, a module for biological dephosphatation of waste water, which is independent of the production module and produces a liquid effluent, and a module for physico-chemical retreatment of the liquid effluent originating from the biological dephosphatation module enabling the incorporation of the effluent into the production module. The production module comprises a strain of microalga that removes the inorganic nutrients contained in the effluent after physico-chemical retreatment, and is composed of same or different, combined or non-combined elements such as open pond, an artificial pond, a closed glass element made of plastic material and undergoing photosynthesis process. The liquid effluent is removed from the dephosphatation module, when the concentration of phosphorus is resulting from the phosphate compound is 5-100 times greater than its concentration in the waste water, and subjected in the retreatment module to destroy the harmful microorganisms during the production of micro-algae. The treatment comprises oxidation of the liquid effluent with hydrogen peroxide solution. During oxidation, the effluent is heated to above 60 degrees C for less than 5 minutes and the pH value of the effluent is adjusted using an acid. The amount of effluent in the production module corresponds to a volume of 1/1000 and 1/50 of total production module after the physico-chemical treatment. The amount of phosphorus consumed by micro-algae in a production cycle is equal to the amount of effluent extracted from the removal module.