Mineralization of ammunition wastewater by a micron-size Fe0/O3 process (mFe0/O3)

Abstract

A micron-size Fe⁰/O₃ process (mFe⁰/O₃) was set up to mineralize the pollutants in ammunition wastewater, and its key operational parameters (e.g., initial pH, ozone flow rate, and mFe⁰ dosage) were optimized by the batch experiments, respectively. Under the optimal conditions, COD removal efficiency obtained by the mFe⁰/O₃ process (i.e., 92.6% after 30 min treatment) was much higher than those of ozone alone (46.5%), mFe⁰ alone (38.3%) or mFe⁰/air (58.5%), which confirm the synergetic effect between mFe⁰ and ozone. In addition, the BOD₅/COD (B/C) ratio was elevated from 0 to 0.54 after 30 min treatment by the mFe⁰/O₃ process, which indicates the significant improvement of biodegradability. Furthermore, the analysis results of the UV-vis and excitation–emission matrix (EEM) fluorescence spectra further confirm that the toxic and refractory pollutants in ammunition wastewater had been completely decomposed or transformed into smaller molecule organic compounds. Meanwhile, the superiority of the mFe⁰/O₃ process has been confirmed according the analysis results of COD removal, B/C ratio, UV-vis and EEM. Therefore, the mFe⁰/O₃ process could be proposed as a promising treatment technology for toxic and refractory ammunition wastewater.