Study On Residues And Removal Technologies Of Cephalosporin Antibiotics In Pharmaceutical Wastewater Treatment Plant

Pharmaceutical wastewater treatment plant (PWTP) is one of the main sources ofantibiotics in environment. However, concentration of cephalosporin residues in PWTPis still unknown. Aiming at uncovering cephalosporin concentration in pharmaceuticalwastewater and exploring efficient advanced wastewater treatment processes, thisresearch established one analytical testing method for9kinds of cephalosporinantibiotics out of pharmaceutical wastewater. With the method, this thesis investigatedcephalosporin concentrations in each processing unit of PWTP, discussed aboutcephalosporin stability at different temperatures and water conditions, and in darknessor lightness, and eventually developed ozone-activated carbon processes withremoving off antibiotic residues in pharmaceutical wastewater oriented. The mainfindings are as follows:(1) Based on the technology of Solid Phase Extraction-Ultra Performance LiquidChromatography tandem Mass Spectrometry, simultaneous determination method of9cephalosporin antibiotics in pharmaceutical wastewater was established. Its recoverieswere above74.9%and the limit of quantitation is27.5~131.8ng/L. Stability andreliability of the method made it satisfy the requirements of cephalosporin antibioticsanalysis in pharmaceutical wastewater.(2) Cephalosporin antibiotic residues in influents of PWTP gained averageremoval rates of at least73%after two-stage bio-oxidation wastewater treatmentprocesses. Concentrations of cefuroxime, cefazolin, ceftriaxone, cefotaxime,cephradine, cephalexin and cefoxitin in detected PWTP effluents were0.75~35.1μg/L,0.8~4.2μg/L,0.88~7.79μg/L,0.7~3.64μg/L,1.22~1.80μg/L,0.07~1.45μg/L and0.18μg/L, respectively. Their environmental risk level is high.(3) Degradation reactions of ceftriaxone, cefazolin, cefotaxime and cefuroxime atdifferent temperatures and illuminations obeyed the rules of first-order reactions. In therange of4~45C, their logarithm of reaction rate constant (ln k, h-1) and reciprocal ofKelvin temperature (1/T, K-1) followed the below linear equations, respectively:lnk=11616/T+33.774, lnk=9282.8/T+25.313, lnk=10680/T+30.332andlnk=10507/T+29.512. In darkness and lightness of4000lx, t0.1value of the fourcephalosporin antibiotics were187~397h and144~250h. In both pharmaceutical wastewater and sewage effluents, their degradation rates were all below45%within144h.(4) Ceftriaxone and cefuroxime in ozone oxidation reactions also obeyed the rulesof first-order reactions. Within ozone dosage of4.6~70.0mg/L, the two cephalosporinantibiotics’ reaction rate constant (k, min-1) and ozone dosage (D, mg/L) followed theindex regression equations, which were k0.03071.0397Dand k=0.07421.0223D,respectively. Ozone of70mg/L dosage in series with activated carbon of5g/L dosageand24h working time almost completely removed cephalosporin residues in effluentsof PWTP, and posed a removal rate of54.26%to effluents’ TOC. Moreover, thisadvanced treatment technology could get rid of over90%of aromatic proteins,hydrophobic acid, and bio-related tryptophan and protein, as well as humic acid inPWTP effluents. The effluents of ozone-activated carbon treatment posed aluminescence inhibition rate of36.5%to Vibrio fischeri.