Piotr Marcinowski, Jan Bogacki, Maciej Majewski, Jarosław Zawadzki, Sridhar Sivakumar
Pollution released into the environment as the result of the combustion of energy fuels is a significant global threat. For instance, wastewater in coal–fired power plants is often heavily polluted by organic compounds, heavy metals and boron. Therefore, there is an urgent need for efficient flue gases and wastewater treatment. However, to be industrially implemented, the treatment processes have to be simultaneously effective and inexpensive. This research systematically studied the efficiency of inexpensive coagulation processes using aluminum-based coagulants applied to flue gas desulfurization (FGD) wastewater treatment. Additionally, the differences in the efficiency of total organic carbon (TOC) and chemical oxygen demand (COD) removal between sedimentation and coagulation processes were systematically studied. It was found that coagulation with the appropriate dose of PAX19XL coagulant achieved a satisfactory effect with significant boron removal and almost complete heavy metals removal. The polyelectrolyte use did not improve coagulation effectiveness and did not accelerate sludgesedimentation and volume decreasing. The detailed statistical analyses did not confirm the positive, pronounced effect of coagulation compared to sedimentation, although there were observed exceptions that should be considered separately. The results obtained suggest that inexpensive aluminum-based coagulants may be effective in improving the efficiency of flue gas desulfurization wastewater treatment in coal–fired power plants.