Abstract: The combined process “three-dimensional electrochemical-A/O” was used to treat simulated and actual fumaric acid wastewater, and the effect of biologically toxic substance thiourea on the degradation process was investigated. The results showed that under the optimized parameters, the COD, ammonia nitrogen, and thiourea of ​​the two wastewater effluents met the first-level standard of the “Integrated Wastewater Discharge Standard”, but the degradation rate of the actual wastewater in the three stages of “three-dimensional electrochemistry + anaerobic + aerobic” was lower than simulated wastewater; Along the way, the three-dimensional fluorescence spectrum showed that after three-dimensional electrochemical treatment, the fluorescence intensity of simulated wastewater peak C （Ex/Em=250~400/380~500 nm） was enhanced, and the fluorescence of actual wastewater peak C was almost unchanged; The intensity of IC anaerobic effluent actual wastewater peak C was equivalent to that of simulated wastewater, and both fulvic acid-like peak D （Ex/Em=200~250/380~500 nm） and tyrosine-like aromatic protein peak E （Ex/Em=200~250/200~330 nm）, soluble microbial organic matter peak B （Ex/Em=250~280/200~380 nm） and tryptophan-like aromatic protein peak A （Ex/Em=200~250/330~380 nm） and other organic matter were derived; The actual wastewater of the oxygen effluent contained a certain intensity peak B, while the simulated wastewater peak B basically disappeared. “Three-dimensional electrochemistry-A/O” had the potential to treat fumaric acid wastewater, and the EC₅₀ calculated by the activated sludge respiration inhibition rate model was 127.73 mg/L, which was much higher than the concentration of thiourea in the effluent （46.52 mg/L）.

Key words: biotoxic wastewater, combined process, degradation effect, three-dimensional fluorescence analysis, respiratory inhibition rate