The Distribution,Migration And Transformation Of β-Lactam Antibiotics In Municipal Wastewater Treatment Plant

The residual β-lactam antibiotics in effluent of municipal wastewater treatment plants may harm human health and ecological environment. So there was an important practical significance to study on migration and transformation of micro-pollutants in municipal wastewater treatment plants.The contents and distributions of the β-lactam antibiotics in municipal wastewater treatment plants were studied by SPE-HLPC-DAD. β-lactam antibiotics(amoxicillin, procaine hydrochloride, cefaclor, ceftriaxone, cefotaxime, cefazolin)could be detected in sewage and sludge of municipal wastewater treatment plants. The contents of6β-lactam antibiotics in influent and effluent of the A municipal sewage treatment plant were0.956μg/L～2.967μg/L and0μg/L～1.988μg/L respectively. Enter a daily average total6kinds of antibiotics and discharged wastewater treatment plants were466.15g and217.33g respectively. The contents of6β-lactam antibiotics in B plant’s influent and effluent were1.322μg/L～2.883μg/L and0μg/L～2.212μg/L respectively. And the total increased amount of6kinds of antibiotics was1043.1g per day,414.38g discharged. While the6β-lactam antibiotics residual contents in sludge of A plant and B plant were0.595μg/g～2.960μg/g and0.290μg/g～2.86μ/g respectively.The kinetics of hydrolysis, photolysis, inactivated sludge adsorption, adsorption of activated sludge and biodegradability of6β-lactam antibiotics were investgated. It was found that the6β-lactam antibiotics hydrolysis conformed to the first-order hydrolysis kinetics equations, and the hydrolysis rate constants was between0.001and0.016. The6β-lactam antibiotics adsorption on inactivated sludge and activated sludge were fitted with Freundlich equation and Langmuir equation well. And the values of△G was less than-20KJ/mol.so the adsorption of antibiotic was mainly physical adsorption process. By analyzing the degradation percents of target antibiotics,we could see hydrolysis, sludge adsorption and biodegradation were main mechanism of lactam antibiotics removed which were existed in municipal wastewater treatment plants.