ECOLOGICAL ASSESSMENT OF WASTEWATER FROM THE DEGREASING STAGE IN THE LEATHER INDUSTRY
Keywords:
Ecological risk, wastewater, chemical oxygen demand (COD), nutrients, surfactant (SFM), gasoline+SFM, leather industry, degreasing, ecological assessment.Abstract
The article examines the ecological condition of wastewater generated at the leather degreasing stage. Three types of degreasing compositions were selected as the research objects: kerosene + surfactant (SFM), a surfactant composition without organic solvent, and a gasoline + surfactant (SFM) working solution based on a by-product. The results were analyzed in tables and graphs, and the ecological risk of the wastewater was assessed by comparing them with regulatory values. It was found that in the kerosene+SFM and especially in the SFM composition variants, the chemical oxygen demand (COD), nutrient content and non-natural substances significantly exceed the permissible limits, which leads to an increase in reagent consumption at treatment facilities and intensifies ecological risk. In the gasoline+SFM variant, the degreasing efficiency is satisfactory, while COD and nutrient concentrations are comparatively lower and closer to the standard values, and non-natural substances remain within the normative range. Therefore, the gasoline+SFM composition is recommended as the most balanced option from both technological and ecological viewpoints for the degreasing process.
