Alicja Knap-Bałdyga, Justyna Czajkowska, Monika Żubrowska-Sudoł
Water reclamation from municipal wastewater offers a sustainable solution to address water scarcity and meet industrial water demands by converting Wastewater Treatment Plant (WWTP) effluents into reusable resources. This study investigates the application of coagulation processes, specifically volumetric and surface coagulation, for treating municipal wastewater to enhance its suitability for industrial reuse, focusing on pollutant removal efficiency and impacts on chemical stability. Aluminum sulfate and polyaluminum chlorides (PAX-XL 19 F and PAX-XL 1911) were evaluated as coagulants at varying dosages (0.25–2.0 mg Al/L for surface coagulation and 1.0–8.0 mg Al/L for volumetric coagulation). Coagulant performance was assessed based on reductions in turbidity, color, chemical oxygen demand (COD), and total organic carbon (TOC), alongside chemical stability indicators, including the Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI), Larson Ratio (LR), and Saturation Index (SI). Both coagulation methods demonstrated effective pollutant removal, with surface coagulation achieving comparable results at lower dosages. For aluminum sulfate, COD was reduced by 34 % at 8 mg Al/L in volumetric coagulation, compared to 30 % at 2 mg Al/L in surface coagulation. Correlation analysis revealed trade-offs between pollutant removal efficiency and chemical stability impact.
