Abstract
The article presents the results of a study on the effect of trivalent iron obtained by a bacterial-chemical method and bentonite on the chemical oxygen demand (COD) of wastewater. Currently, various methods are used to treat wastewater containing detergents. One of the most common is the adsorption method, particularly using carbon-based materials as adsorbents. Wastewater treatment by coagulation is also widely applied, using coagulants such as aluminum sulfate or iron salts. The aim of the study was to reduce the chemical oxygen demand (COD) of wastewater containing detergents by applying trivalent iron obtained through a bacterial-chemical process using bentonite. The research methods included bacterial isolation and cultivation by the serial dilution method, COD determination according to GOST standards, mathematical modeling using artificial intelligence, and statistical data processing on a Pentium-IV PC using the Microsoft Excel statistical software package. As a result of the study, the possibility of using Fe₂(SO₄)₃ obtained by a bacterial-chemical method with A. ferrooxidans BIT 1 sulfur-oxidizing bacteria was established. Under conditions of combined use of bacterial–chemical trivalent iron (1.75 g/L) and bentonite (600 mg/L), the maximum COD reduction of wastewater reached 88.1±7.9%. When Fe₂(SO₄)₃ was applied at 1.75 g/L and bentonite at 100 mg/L, the COD reduction degree was 75.7%.