Optimization of coagulation wastewater treatment of leather industry

The object of the study was the process of coagulation treatment of wastewater of leather industry enterprises. The treatment of samples of real wastewater from a leather production was investigated. Such wastewater is characterized by high concentrations of pollutants of varying degrees of dispersion, which is due to the use of a large number of various chemicals in the leather production process. During technological operations related to the skinning and processing of skins, these substances enter the wastewater, which is discharged into the sewer. A peculiarity of leather production wastewater is large fluctuations in composition and volume, high concentrations of pollutants, and an increased content of suspended solids. Such waters have certain toxicity. The existing methods of wastewater treatment of leather industry enterprises do not provide the necessary treatment efficiency, do not allow to create a closed circulation of water at enterprises, to use or regenerate valuable components of wastewater, and to ensure their economically feasible disposal. Therefore, the research is aimed at improving the process of coagulation wastewater treatment of leather factories using mathematical modeling and optimization methods. This will make it possible to modernize existing wastewater treatment schemes. The experiments were carried out on the Niva Jar-test laboratory unit, which allows simultaneous examination of 6 samples. Samples of wastewater from leather production after the fattening-filling and dyeing stages were studied. The effectiveness of the coagulation process was determined by the degree of wastewater treatment. The factors were analyzed and the intervals of variation of factors that have a significant impact on the process of coagulation treatment of wastewater from leather factories were established. An experiment plan was drawn up and implemented in order to study the effect of coagulants based on aluminum and ferrum, as well as flocculants on the quality of wastewater treatment. The choice of quality indicators of the coagulation process is substantiated. A statistical analysis of the results of experimental studies was performed, a correlational analysis of the interdependence of parameters and indicators of the quality of the coagulation process was performed. Aluminum-based coagulant has been found to be more effective than iron-based coagulant. The results of mathematical modeling were used to determine the optimal parameters of the coagulation process: pH 10, coagulant dose – 2.5 g/dm3, flocculant dose – 100 mg/dm3.