Derı̇ endüstrı̇sı̇ atıksuları: Polı̇mer bazlı hı̇brı̇t malzemelerı̇n koagülasyon-flokülasyon ve çamur azaltmadakı̇ performansı

Leather industry effluents are among the most challenging wastewater types, requiring treatment strategies that provide high pollutant removal with reduced chemical use and environmental impact. This study develops hybrid coagulants by combining inorganic coagulants with organic polymers such as polyDADMAC and polyamine, supported by PAM as a flocculation aid. Sixteen hybrid formulations were screened under six treatment scenarios (M1–M6) using twenty-two real wastewater samples collected during high- and low-activity periods at the Çorlu Organized Industrial Zone WWTP, one of Türkiye's tannery wastewater centers. The best-performing formulations were optimized and compared with the conventional 40% alum process, focusing on COD, TOC, TSS, heavy metals, and sludge characteristics. Phase-based jar tests enabled separate evaluation of liquid and solid phases, allowing more precise performance interpretation and mass balance assessment. Environmental performance was examined using an entropy-weighted TOPSIS approach incorporating sludge management, long-term robustness, chemical burden, and treatment efficiency. Biodegradability of the organic polymers was additionally evaluated using U.S. EPA BIOWIN predictions to assess their environmental persistence. Overall, hybrid coagulants significantly reduced dosage requirements and sludge production while maintaining high removal efficiencies even at natural pH. Although the polymers showed limited biodegradability, their low dosing minimized long-term concerns. The findings position hybrid coagulants as a technically effective and environmentally conscious alternative to conventional coagulation and highlight the importance of future research supported by life cycle assessments of polymer systems. The study also suggests that comparable or improved performance may be achieved with more biodegradable materials and broader testing across different industrial wastewater types.