Simultaneous Recovery of Potassium, Chloride and Removal of COD from Landfill Leachate Concentrates Using a Combination of Cation-Exchange Membrane Electrolysis
This study demonstrated that the proposed combined process can effectively remove 82%, 99%, 34%, 99% of organic matter, ammoniacal-nitrogen, total nitrogen, and chloride ions, respectively. And the recovered gaseous chlorine was reused on site as a decolorizing agent for synthetic dye (RhB) containing wastewater and complete decolorization was also achieved. The potassium ions were recovered via magnesium potassium phosphate crystallization . Additionly, about 53% of the potassium (from 2762 mg/L to 1389 mg/L) was removed via formation of magnesium potassium phosphate(MgKPO4·6H2O) precipitate.
A combination of membrane electrolysis process is demonstrated to be an effective method for the convenient recycling of NF concentrates generated from a landfill plant. This combined process achieves effective removal of organic pollutants in the concentrates and complete removal of NH3-N via an active chlorine-mediated reaction. The combined process also simultaneously enables highly efficient recycling of chloride and potassium ions from NF concentrates as beneficial products (gaseous chlorine and MgKPO4·6H2O buffered fertilizer, respectively). Additionally, we have demonstrated that the recovered gaseous chlorine could be reused on site as a decolorizing agent for treating colored wastewater (i.e., RhB solution), and that complete decolorization could be achieved. The results indicates that recycling of NF concentrate via the combination process is feasible.