Characterizing the degradation of refractory organics from incineration leachate membrane concentrate by VUV/O3

In this study, we used a combined vacuum-ultraviolet (VUV) and O-3 process treating the chemical precipitation pre-treated incineration leachate membrane concentrate to further decompose substantial refractory organics which led to membrane organic fouling in the subsequent membrane distillation process. The highest removal of COD (88.1%) was achieved when 50 mg/min of O-3 dosage was used at a pH of 11.5-12. Multi-spectrum methods, molecular weight distribution (MW), gas chromatography-mass spectrometry (GC-MS), two-dimensional correlation spectroscopy (2D-COS), and hetero-spectral 2D-COS were used to investigate the organics degradation mechanism. The combined action of O-3 and hydroxyl radicals (center dot OH) effectively degraded macromolecular organics with high aromaticity and high conjugation (mainly distributed at 1-3 kDa) into aliphatic products with lower molecular weight (<1 kDa) and simple structures. The order of organics that were oxidized were humiclike acids > fulvic-like acids > protein-like substances. Organic acids (acetate, propionate, and butyrate) also accumulated in the VUV/O-3 systems.

Automated summary

In this study, a combined VUV and O3 process was used to treat incineration leachate membrane concentrate, achieving significant removal of COD by degrading refractory organics into simpler structures. Various analytical methods were employed to investigate the degradation mechanism and types of organics, indicating the effectiveness of the combined action of hydroxyl radicals and O3 in degrading macromolecular organics.