Optimising Chemical Treatment of Dairy Wastewater for Sustainable Protection of Karst Ecosystems

Slovenia is among the few countries where the olm, Proteus anguinus, is found, with its habitat largely coinciding with Natura 2000 sites. In these regions, various agricultural and food-processing activities, including the dairy industry, have developed. Krepko, a dairy facility, is situated directly within the olm’s habitat. Current legislation prohibits the direct discharge of dairy wastewater into the environment and mandates prior treatment. This study examined the primary treatment phase, specifically the chemical processing steps of neutralisation, coagulation, and flocculation. Field jar tests, pH measurements, and laboratory analyses of chemical oxygen demand (COD) were employed to assess the effectiveness of various chemicals. The findings indicate that sodium hydroxide with higher molarity enables faster and more stable neutralization, while polyaluminum coagulants and acidic flocculants are more effective than traditional reagents in reducing COD. The optimised chemical treatment process substantially reduced the organic load of wastewater and, consequently, the potential impacts on karst habitats. The improved treatment system represents a significant advancement in reducing pressure on karst water resources and protecting the habitat of the olm, thereby contributing to the achievement of the United Nations Sustainable Development Goals, particularly SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), and SDG 15 (Life on Land).