437 / 2024-04-17 14:21:00

Removal of Ammonia from an Explosive Impacted Mining Wastewater using Zeolite

Ion-exchange,zeolite,ammonia removal,Chlorine regeneration

Zeolite ion-exchange (IE) column system has been suggested as a viable option for the removal of total ammonia nitrogen (TAN) from explosive impacted mining wastewater (EIMWW) in cold regions. The objective of this bench-scale study was to compare the effectiveness of several NaOCl, NaOCl-NaCl and NaCl regeneration solutions on the performance of a zeolite column loaded with a synthetic EIMWW. The three regeneration schemes did not significantly impact the TAN uptake. However, the combined NaOCl-NaCl regeneration was faster and had a much shorter low pH period than the NaOCl regeneration. And unlike the NaCl regeneration, the used regenerant was essentially TAN free. Thus, this is the most promising approach because it permits regenerant reuse and avoids creating a secondary waste stream. It was also confirmed that effluent pH, total chlorine level, and free chlorine levels during the chlorine regeneration were positively related, thus it seems the ammonia is oxidized to nitrogen gas accompanied by production of hydrogen ions. The regeneration of the sites containing K and Ca appear to be accomplished through the Na ions in the NaOCl solution and H⁺ ions generated in the breakpoint chlorination reaction.