OBTAINING THE MATHEMATICAL MODEL AND MULTIPLE REGRESSION EQUATIONS OF THE NEUTRALIZATION PROCESS OF PHENOL-CONTAINING WASTEWATER

Abstract

In this work, the object of study was selected as the phenol effluents of the biochemical treatment unit of the cokechemical enterprise of Kamianske, PJSC "KAMET-STEEL". Under its conditions, the regulatory values of the quality of the initial effluents were approved, which for phenols are 415 mg/dm³; for rhodanides – 400 mg/dm³; and the actual concentration of C6H5OH (average for the year) is – 1115.9 mg/dm³, SCN− – 601.1 mg/dm³.The given data indicate that the unevenness of the process of biological wastewater treatment should be expected during the year, which will lead to a negative effect of toxic substances on the symbiosis of activated sludge. In order to improve the quality of phenolic water supplied to aeratanks, there is a need to further purify the effluents at the mechanical stage. Based on the experimental data, regression equations were obtained that allow determining the residual concentration of phenols and rhodanides depending on the doses of glauconite and the contact time of the adsorbent with wastewater. The optimal consumption of glauconite in combination with a 0.1% solution of a cationic flocculant according to the first model of purification is 2 – 4.8 g/dm3 with a duration of the experiment of 100 – 110 min, which leads to a decrease in the concentration of phenols from 510 mg/dm3 to 340.9 mg/dm3. According to the second model, the maximum degree of rhodanide extraction is achieved with a glauconite consumption of 2 – 5 g/dm3 in combination with a 0.1% cationic flocculant solution and a time interval of 115 minutes, which leads to a decrease in the rhodanide concentration from 475.2 mg/dm3 up to 345 mg/dm3. The obtained multiple regression equations adequately describe the results of experimental studies. Practical reduction of phenols and rhodanides to the MPC can be obtained at the values of glauconite flow rate X2 (2 – 5 g/dm3) and the cleaning time interval X3 (100 – 115 min). The optimal contact time of the sorbent does not exceed the residence time of the effluents in the flotation device and satisfies the technological requirements. The adequacy of the equations was checked by the Fisher criterion. According to the tabular data, it was determined that the extraction of phenols by the Fisher criterion is: F1 = 1.9. As a result, we obtain: 0.461≤ 1.9. Removal of rhodanides: F2 = 1.9, which as a result is: 0.369≤ 1.9. The equations are adequate to the experimental data.