ANALYSIS OF TECHNOLOGIES AND EQUIPMENT FOR THE TREATMENT OF WASTEWATER CONTAINING ETHYLENE GLYCOL
Abstract
The article presents a comprehensive analysis of modern technologies and equipment for ethylene glycol removing from industrial airport wastewater. The relevance of the topic is due to intensive use of deicing fluids by Russian civil aviation, which creates a significant environmental burden on natural water bodies due to the toxicity of glycols and their high biological oxygen demand. Furthermore, the irreversible discharge of this reagent leads to direct economic losses for aviation enterprises. The paper examines in detail physicochemical pretreatment methods: coagulation with aluminum and iron salts with pH optimization, dissolved air flotation for oil removal, adsorption on activated carbon and zeolites, and ion exchange. Particular attention is paid to physical phase separation processes — gravitational settling, lamellar sedimentation, and filtration through granular media (slow sand filters, rapid multimedia filters). The critical role of baromembrane processes (micro-, ultra-, nanofiltration and reverse osmosis) as the most effective deep water purification tool is emphasized. A central place is taken by a comparative analysis of the ethylene glycol regeneration methods. There are considered: vacuum distillation, which allows component separation without thermal degradation; energy-efficient membrane processes (reverse osmosis and pervaporation); promising thermal diffusion methods using a temperature gradient; and biological methods of destruction. Within the framework of biotechnology, aerobic systems with activated sludge, anaerobic methanogenic reactors (USAB), trickling biofilters, and integral membrane reactors are analyzed. Scientific novelty lies in the substantiation of hybrid process schemes that combine the advantages of various processes to create a closed water management cycle. The practical significance is confirmed by the possibility of scaling the solutions for Russian airports of the Moscow air hub (Sheremetyevo, Domodedovo, Vnukovo) and Yaroslavl International Airport «Golden Ring». A specific process flow diagram for the Yaroslavl air hub, including mechanical cleaning, chemical flocculation treatment, cascade ultrafiltration with reverse osmosis, and a final stage of vacuum-evaporative distillation with condensation heat recovery is developed. An economic analysis shows that this flow diagram implementation reduces operating costs for antifreeze by 30-50 % and lowers energy consumption for water treatment systems by 20-25 %. The environmental benefit is reflected in a reduction in the discharged ethylene glycol concentration from an initial 510 to less than 0.1 mg/L, which complies with SanPiN 2.1.5.980-00. The final part of the article assesses the limitations of the proposed technologies: the need for regular chemical membrane cleaning to remove biofouling, high capital expenditures on corrosion-resistant equipment, and the need for complex control automation. Research prospects include the selection of degrader strains, the development of self-cleaning nanomembranes, and the integration of solar collectors. Implementation of such solutions will enable the Russian aviation industry to transition to circular economy principles and significantly improve the environmental safety for aviation facilities.