Wastewater often contains some toxic organic compounds particularly difficult to clean due to their poor biodegradability and high toxicity. Such type of wastewaters needs careful treatment before discharge into the receiving bodies of water. Activated carbon adsorption, solvent extraction, chemical oxidation and electrochemical methods are the most widely used ones for removing such compounds from wastewaters. These approaches are often ineffective because they merely transfer the organic pollutants from water to another medium without degrading or mineralizing the organic pollutants. The method of heterogeneous photocatalysis, one of the measures employed in modern advanced oxidation processes (AOPs), has been used to remove or mineralize a wide range of organic pollutants. Several semiconductors can act as photocatalysts but TiO2 stands out as the most effective photocatalyst and has been extensively used in water and wastewater treatment studies because it is cost effective, thermally stable, non-toxic, chemically and biologically inert, strong photoactive and is capable of promoting oxidation of organic compounds. However the large scale application of this treatment technology is constrained by several factors such as: low adsorption capacity, strong tendency to agglomeration of nano sized TiO2 particles resulting in reduction or even complete loss of photocatalytic activity; problem of separation of nanosized particle powder in the aqueous media after the photocatalytic process. Many techniques of immobilization have been developed to attach the TiO2 powder to simplify the cleaning stage after the photocatalytic process. The dispersion of TiO2 nanosized particles into porous material is the solution of the problem. Diatomite is an important porous non-metallic resource with nontoxic and good chemical stability. Application of diatomite as carrier material may enhance the TiO2 nanosized particles distribution in suspension which enables to adsorb and concentrate the target substances. There are a number of methods for preparing hybrid photocatalysts based on nanosized titanium dioxide and a mineral substrate. Basically, this is a heterogeneous chemical deposition of titanium dioxide from titanium alkoxides or titanium tetrachloride as a precursor of nanosized titanium dioxide. A common disadvantage of the described methods is the use of chemical reagents, the multistage and long duration of the process of obtaining titanium dioxide in the composite. The electrochemical method developed for the preparation of a hybrid photocatalyst based on nanosized titanium dioxide and local diatomite as a substrate is free of these disadvantages. It is as follows: 2.0 g of purified diatomite dispersed in a solution of TiCl4 of the required concentration in the cathode chamber of the electrolyzer and stirred for 30 minutes. Then a constant current is applied to the electrical contacts of the electrolyzer until a certain pH is reached in the cell. Then the current is turned off, the contents of the cell are filtered, washed with distilled water, dried at room temperature, then in an oven at 100°C, and calcined at 400°C for the development of the anatase phase. The resulting product -NTD- is further stored in a desiccator for further physicochemical and photocatalytic studies.