Combined High-Temperature Acid Digestion, Iron-Carbon Micro-electrolysis, and Coagulation Reaction for Degrading Pharmaceutical Wastewater with a High Concentration of Dimethylformamide

The degradation of pharmaceutical with high concentrations of N,N-dimethylformamide (DMF) mainly includes chemical oxidation and physical adsorption. However, these methods have low efficiencies and high expensive. Hence, this study combined the high-temperature acid digestion, iron-carbon micro-electrolysis, and coagulation reaction, which was used to degrade the pharmaceutical wastewater with a high concentration of dimethylformamide. These results showed that the organic nitrogen of wastewater was mostly converted to ammonia nitrogen as the high-temperature acidolysis reaction. The ammonification rate of DMF wastewater increased with the increase of acidity and reaction time. The ammonification rate of DMF wastewater reached more than 80% as the high-temperature acidolysis reaction, the degradation rate of chemical oxygen demand (COD) reached 30%, and the removal rate of total nitrogen was 15%. After pretreatment, iron-carbon micro-electrolysis in combination with coagulation reaction further increased the COD degradation (about 25%). The removal rate increased with the increase of dosage. This method had a noticeable effect on the ammonification, COD degradation, and biochemical enhancement of high-concentration DMF pharmaceutical wastewater in pharmaceutical plants.