Treatment of Raw Mixed Dairy Wastewater Using an Attached-Growth Biological Filter

This study investigates the implementation of an attached-growth pilot-scale biofilter for the biological treatment of mixed dairy wastewater derived from real industrial effluents, consisting of equal proportions of raw second cheese whey (SCW) and pudding dessert wastewater (PDW). The biofilter was inoculated with indigenous microorganisms derived from the mixed wastewater stream with initial dissolved Chemical Oxygen Demand (d-COD) concentrations ranged from 1000 to 12,500 mg/L. The removal performance of organic and inorganic components was evaluated at a recirculation rate of 1.0 L/min, resulting in d-COD reductions of up to 92.3% and removal rates reaching 194.6 mg/(L·h). High removal rates were recorded for ammonium (up to 99.9%) and TKN (92.2–98.7%), while nitrate removal varied (29.4–89.3%) and solids removal exceeded 92%. d-COD concentrations of treated effluent consistently met discharge or municipal disposal legislation values, demonstrating the system’s efficiency and stability and proposing it as an ideal solution for wastewater treatment in dairy facilities.