Treatment Performance and Degradation Process of Contaminants in Vitamin B12 Wastewater.

Vitamin B12 wastewater, as a pharmaceutical wastewater, is difficult to treat due to its high concentrations of bioresistant organic matters, salinity, chromaticity, and poor biodegradability. A laboratory-scale microelectrolysis (ME) process with aeration device was designed to treat this wastewater. Our results suggested that, under obtained optimal condition of hydraulic retention time of 80 min, initial pH of 3, and air/water ratio of 100:1, the removal efficiency of chemical oxygen demand, ammonia nitrogen (NH3-N), and chromaticity in the wastewater by ME process was achieved by 43.9%, 7.9%, and 82.6%, respectively. Organic matter with benzene ring was largely removed or degraded and, therefore, C = C and C = O bonds were destroyed, and substituents of aromatic rings contained more aliphatic chains after treatment by ME process. All wastewater samples were divided into three parallel factor analysis components: one protein-like (component 1 [C1]) and two humic-like components (component 2 [C2] and component 3 [C3]). Fluorescence analysis results demonstrated that humic-like and fulvic-like substances with macromolecular weight and complex structure were decomposed or degraded into smaller molecular weight substances by ME process, in addition to those easily degradable protein-like components. We further demonstrated that biodegradability of vitamin B12 wastewater after treatment by ME process was increased using biodegradability index, suggesting that the ME process can greatly improve the removal efficiency of contaminants in wastewater by subsequent treatment process. [ABSTRACT FROM AUTHOR]