Cleaning of Wastewater Contaminated with Petroleum Products

Environmental pollution caused by oil industry products remains a pressing issue today. Oil-producing, transporting, and refining enterprises have accumulated and continue to generate production waste containing harmful substances, with pollutant concentrations exceeding regulatory limits. This study aims to address the urgent need for the collection, treatment, and disposal of contaminated oil and water streams. The study builds upon the authors’ previous work and patented methods using a multistage process that integrates coalescing and electrochemical filters, along with an electrolyzer, to address contamination in industrial wastewater. The experiments were conducted on natural groundwater contaminated with petroleum products and heavy metals from the Sterlitamak Petrochemical Plant in Russia. The proposed technological scheme effectively treated contaminated water by reducing petroleum product concentrations, suspended solids, and heavy metals such as copper and zinc. The results indicated that at a voltage of 30 V and a copper concentration of 10 mg/L, the removal efficiency reached 85.7% ± 4.2% (p = 0.008), which was the highest observed value. Additionally, it was found that at a voltage of 20 V and a copper concentration of 5 mg/L, the efficiency was 72.4% ± 3.3% (p = 0.03). To assess the differences between the two most effective conditions (30 V and 10 mg/L copper concentration vs. 10 V and 1 mg/L copper concentration), the t-test revealed a statistically significant difference [t(4) = 5.87, p = 0.01], with a 40.5% difference in copper removal. The proposed technology provides an efficient and innovative method for cleaning oily wastewater, utilizing coalescing and electrochemical filters and an electrolyzer. This technology ensures that treated wastewater meets regulatory standards for discharge or can be used for injection into infiltration wells. The novelty of the method is confirmed by the authors’ patents.