Despite the fact that the problem of petroleum-containing wastewater treatment has existed for decades, it is not completely solved due to the lack of optimal the method of solving the problem from the point of view “cost – results”. Therefore, the treatment of petroleum-containing waste water, giving in the amount of a huge amount of waste, difficult to handle in conventional ways, is an urgent task, especially for small and medium-sized enterprises. The article presents an approach to solving the problem of wastewater treatment by physical and chemical means, which creates the prerequisites for a more efficient treatment of petroleum effluents technically auxiliary materials, such as synthetic flocculants. The technological properties of flocculants with different molecular weight, charge and degree of ionicity are investigated. The dependences of the processes of swelling, adsorption, the rate of petroleum products` cover formation on the surface of wastewater of a refinery on the type of flocculant are determined. The advantages of this method of treatment in comparison with other methods of improving the purity of wastewater of petroleum refineries are described.