Degradation of kanamycin from production wastewater with high -concentration organic matrices by hydrothermal treatment

It is known that many kinds of fermentative antibiotics can be removed by temperature enhanced hydrolysis from production wastewater based on their easy -to -hydrolyze characteristics. However, a few aminoglycosides are hard to hydrolyze below 100 degrees C because of their stability expressed by high molecular energy gap (triangle E). Herein, removal of hard -to -hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated. The results showed the reaction temperature had a significant impact on kanamycin degradation. The degradation half-life (tv2) was shortened by 87.17 -fold when the hydrothermal treatment temperature was increased from 100 degrees C to 180 degrees C. The t(1/2) of kanamycin in the N2 process was extended by 1.08 -1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180 degrees C, indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis. However, the contribution of hydrolysis was calculated as 75%-98%, which showed hydrolysis played a major role during the process, providing possibilities for the removal of kanamycin from production wastewaters with high -concentration organic matrices. Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis. More importantly, hydrothermal treatment could remove 97.9% of antibacterial activity (kanamycin EQ 1,109 mg/L) from actual production wastewater with CODcr around 100,000 mg/L. Furthermore, the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment. Therefore, it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high -concentration hard -to -hydrolyze antibiotic residues from wastewater with high -concentration organic matrices. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.