Removal and recovery of perchlorate from fireworks production wastewater through ion exchange and biological...

Ion exchange is often used to remove perchlorate from various wastewaters. This study evaluated the performance of four representative anion exchange resins for removing perchlorate from wastewater. Perchlorate was recovered from the regenerant brine concentrate and further treated through biological methods. The adsorption equilibrium data were well-fitted to the Freundlich isotherm, suggesting that perchlorate adsorption occurred on a heterogeneous resin surface under favorable conditions. Under conditions of high perchlorate concentrations, high salinity, and dissolved organic matter, the anion exchange resins with both polystyrene and polyacrylic matrices exhibited excellent perchlorate adsorption and superior perchlorate selectivity. After the first regeneration step, most ion exchange sites in polyacrylic IRA958 were recovered within five bed volume of the regenerant, while only 24.8% of the sites were recovered for the polystyrene A520E resin. Additionally, solid-phase KClO₄ crystals were readily recovered from the IRA958 waste regenerant and achieved a purity higher than 90% owing to the high perchlorate concentration and low solubility of KClO₄. During the biological degradation process, perchlorate concentrations gradually decreased from 1371 mg/L to nearly zero within 72 h, while methane yield increased. Our results indicate that the combination of ion exchange, perchlorate recovery, and biological reduction processes effectively reduces operating costs and eliminates waste from wastewater. This approach has significant potential for treating wastewater from fireworks production and supports environmental sustainability goals.