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Landfill leachate treatment involved with the membrane bioreactor (MBR) combined with membrane treatment via nanofiltration (NF) and/or reverse osmosis (RO) is widely used in Turkey. This treatment produces landfill leachate membrane concentrates (LLMCs) with an undesirably high concentration of contaminants. In the study, two different nanofiltration concentrates of leachate were coagulated. Coagulant dosages from 0.10 to 5.0 g of Me3+/L (Me3+: Al3+ or Fe3+), and the pH values ranged from 4.0 to 8.0 and 3.0–9.0 for Al-based and Fe-based coagulants, respectively. The most efficient pH values were 5.0 and 4.0 for Al3+ and Fe3+, respectively. These pH values are lower than those known to be effective in coagulants. The reason for this is the presence of humic substances in the wastewater. The cost of Fe 2 (SO 4) 3. xH 2 O was the lowest than other coagulants at the end of the cost analyses obtained from İstanbul region landfill leachate NF concentrate (NFCL-1) and Kocaeli region landfill leachate NF concentrate (NFCL-2). Under optimum conditions, the costs for NFCL-1 and NFCL-2 were calculated as 0.55 and 0.46 $/removed kg COD, respectively. [Display omitted] • Landfill leachate membrane concentrates was coagulated. • In total, four different types of Al3+ and Fe3+ salts were used. • Detailed cost analysis of the obtained results was presented. • Ferric sulfate and aluminum sulfate were determined as cost-effective coagulants. • The best precipitations were obtained at pH 5 for Al3+ and at pH 4 for Fe3+. [ABSTRACT FROM AUTHOR]

Printing and packaging process wastewater (PPPW) with high flow rates causes severe damage to the environment due to high organic pollution (3830.0 mg O 2 /L of COD and 813.6 mg/L of TOC) and turbidity (9110 NTU). This study examined the efficiencies of coagulation, Fenton, and photo-Fenton procedures, and their combinations in the treatment of PPPW. The three inorganic salts (FeCl 3 , Al 2 (SO 4) 3 , and Fe 2 (SO 4) 3) were used in a wide range of pH (2.5–10) as a coagulant, and FeCl 3 was chosen as the optimum coagulant. The 71.3% of TOC removal and the decreasing of turbidity up to 5.8 NTU were obtained at 0.5 g/L FeCl 3 and pH of 6.0. Then, Fenton and photo-Fenton processes were applied to the effluent of the coagulation process. The Fenton process engaged the TOC removal efficiencies up to 85.2% in the presence of 7.350 g/L iron catalysts and 36.0 mL/L H 2 O 2. The combined coagulation and Fenton process is a promising way to decrease the COD up to 119 mg O 2 /L, meeting the wastewater discharge standards of COD (200 mg O 2 /L) in Turkey. However, adding UV sources to the Fenton process showed a little bit of engagement (only %1.4 extra removal). When evaluated for PPPW, it is seen that the usage of combined coagulation and the Fenton process is an important treatment alternative. Furthermore, Zeta potential measurements and size exclusion chromatography were used to understand the removal mechanism. [Display omitted] • Real wastewater treatment with the combined use of coagulation and Photo-Fenton. • For coagulation, FeCl 3 , Al 2 (SO 4) 3 and Fe 2 (SO 4) 3 were studied at wide pH ranges. • 71.3% of TOC removal were obtained at 0.5 g/L FeCl 3 coagulation. • 85.2% Total TOC removal was achieved combined coagulation and Photo-Fenton. • Combined coagulation and the Fenton process is an efficient tool for PPPW treatment. [ABSTRACT FROM AUTHOR]