Research On The Composting Treatment For Antibiotic Fermentation Dregs

The harmless effect of high-temperature composting on antibiotic fermentation dregs was studied based on the comparison with sludge.Lincomycin fermentation dregs,penicillin fermentation dregs,erythromycin fermentation dregs were mixed with auxiliary materials,respectively.The sludge-adjunction was composted as CK.The physicochemical properties,microbial changes and antibiotic residues in the composting process were measured to determine the composting effect.The safety of the composting process was evaluated through seed germination test and pot experiment.Besides,the strains with high temperature resistance and high degradation rate were screened from the compost samples of lincomycin residue at high temperature by enrichment domestication method aiming at the slow degradation rate of lincomycin residue.The main research results are as follows:(1)Composting test of antibiotic residue fermentation dregs.High-temperature composting with antibiotic residue has fast fermentation speed,and residual antibiotics can be degraded completely or substantially.The composting began after mixing antibiotic residue with excipients evenly and adjusting its moisture content to 60%.The results show that during composting the heating rate of the three experimental groups is significantly faster than CK,moreover,the heating rate of erythromycin residue compost is the fastest.The high temperature durations of erythromycin,penicillin and lincomycin residues compost was 22 days,16 days and 19 days,respectively.At the end of composting,the organic matter content of erythromycin and penicillin residue is 46.0% and 45.0%,respectively,and the total nutrient content is 5.41% and 6.68%,respectively,which meets the requirements of organic fertilizer standard for organic matter content ?45% and total nutrient content ?5.0%.After composting,the penicillin and erythromycin are all degraded,which indicates that the purpose of using compost for harmless and resourceful is achieved.After composting,the lincomycin was degraded 76.5%.(2)Safety evaluation of composting treatment for antibiotic fermentation dregs.The safety of applying antibiotic residue as garden fertilizer has been greatly improved after high temperature composting treatment.After composting,the seed germination indexes GI of penicillin fermentation residue and erythromycin fermentation residue increaseding from 0% to 86.2% and 92.7%,respectively,has achieved the practical non-phytotoxicity level.In pot experiment,the growth of Chinese cabbage treated with penicillin residue decomposed sample is good,and the overall growth of Chinese cabbage achieves the best when the amount of fertilizer is 1.0 t/mu,which is better than common organic fertilizer under the same conditions.The results showe that when the amount of erythromycin residue is 1.0-2.0 t/mu,Chinese cabbage grows well and can achieve the same effect as common organic fertilizer.After composting,the seed germination index GI of lincomycin residue increased from 1.69% to 29.63%,indicating that lincomycin residue composting was still biotoxic.As organic fertilizer,it would cause growth slowly and plant dwarf of Chinese cabbage.The results show that lincomycin residue compost still had phytotoxicity,and further measurements are needed to eliminate harmful factors to plant growth.(3)Screening of lincomycin degrading strain and its application.Six strains with high temperature tolerance and high degradation rate of lincomycin were screened.The effect of simulation experiment on the degradation of lincomycin in composting process was studied.The degradation rate of lincomycin in pure was F2 > F3 > B2 > F4 > B1 > F1,while the rate of lincomycin in composting test was F4 > B2 > F1 > F2 > B1 > F3.Further studies on F4 show that with the increase of C/N,the removal rate of lincomycin increased at first and then decreased.The results show that the degradation rate of lincomycin is higher when the initial C/N is 25.Strain F4 has promising applications to improve the degradation of lincomycin in actual composting.