| Oxytetracycline is a common veterinary antibiotic,which fermentation process will produces a large amount of residual waste,it also called oxytetracycline bacterial residue,which belongs to hazardous waste,how to deal with oxytetracycline bacterial residue is a difficult problem for enterprises.Oxytetracycline bacterial residue is treated as the research object in this paper,then we put forward a kind of innovative bacterial residue processing pattern and push forward this experiment,bacterial residue was adjusted to 98%moisture content before the test,the experiment's method is alkali-hydrothermal pretreatment first,then followed by biological treatment of ASBR-SBR combination process,the first test aim to explore the influence on the effect of different reaction conditions on the bacterial residue reduction and removal effect of terramycin,second half of the test to explore the tail liquid in bacterial residue alkali-water heat treatment in the best condition of biochemical treatment.It provides theoretical support and technical reference for the safe and efficient treatment of oxytetracycline bacterial residue.The alkali-water heat treatment was carried out on the bacterial residue,and the results were as follows:?1?The orthogonal test results show that the order of the influence on SS decrement rate under different factors is:Reaction temperature>Alkali dosing quantity>Reaction time.The optimum reaction time was determined to be 2h by condition optimization test.?2?The test conditions which achieves maximum SS decrement rate was 0.12gNaOH/gTS for alkali dosage,120?for reaction temperature and 2h for reaction time.Under this condition,SS decrement rate is averaged 44.13%,and SS content decreased from an average of 18941 mg·L-1 to an average of 10583 mg·L-1.?3?The test conditions which achieves maximum TS decrement rate was 0.10gNaOH/gTS for alkali dosage,120?for reaction temperature and 2h for reaction time.Under this condition,TS decrement rate is averaged 14.40%,and the content of TS decreased from an average of 19023 mg·L-1 to an average of 16284 mg·L-1.?4?The test conditions which achieves maximum oxytetracycline decrement rate was0.08 gNaOH/gTS for alkali dosage,120?for reaction temperature and 2h for reaction time.Under this condition,oxytetracycline decrement rate is averaged more than 99.99%,and the content of oxytetracycline decreased from an average of 1.415 mg·mL-1 to an average of0.0002 mg·mL-1.?5?TCOD is about 18927?20418 mg·L-1,and has little change before and after the reaction,but SCOD was changed significantly before and after reaction,SCOD is about884?1036 mg·L-1 before reaction,while has a large amount of dissolution after reaction,the condition of maximum dissolution rate is 0.12 gNaOH/gTS for alkali dosage,120?for reaction temperature and 2h for reaction time.under this condition,the COD dissolution rate is an average of 45.82%,and SCOD content is from an average of 976 mg·L-1 rise to an average of 9920 mg·L-1.?6?The experimental conditions for the maximum ammonia nitrogen dissolution rate were the alkali dosage of 0.14 gNaOH/gTS,the reaction temperature of 120?,and the reaction time of 2h.Under these conditions,the ammonia nitrogen dissolution rate reached an average of 728.2%,and the ammonia nitrogen content is increased from an average of 36.9mg·L-1 to an average of 305.6 mg·L-1.?7?The experimental conditions for the maximum nitrate dissolution rate is the alkali dosage of 0.14 gNaOH/gTS,the reaction temperature of 75?,and the reaction time of 2h.Under these conditions,the nitrate dissolution rate reached an average of 353.4%,and the nitrate content increased from an average of 22.6 mg·L-1 to an average of 102.3 mg·L-1.?8?The experimental conditions for the maximum total nitrogen dissolution rate is the alkali dosage of 0.14 gNaOH/gTS,the reaction temperature of 120?,and the reaction time of2h.Under these conditions,the total nitrogen dissolution rate reached 918.8%on average,and the total nitrogen content increased from 72.0 mg·L-1 to 733.1 mg·L-1 on average.ASBR-SBR combined process was used for biological treatment of the bacterial residue's mixed solution after alkali-water heat treatment.ASBR's inlet concentration is divided into 5 stages.COD is used as the reference standard,and COD gradually increases with the number of stages.The reaction period of ASBR is 4d,while the water inlet of SBR is the water outlet of ASBR,and the reaction period is 3h.The test results are as follows:?1?COD was removed largely in the anaerobic reaction of ASBR.On the whole,COD reduction rate reached the maximum in the phase V.Among them,the average COD reduction rate was 26.1%in 1d,42.2%in 2d,51.9%in 3d and 55.5%in 4d.The COD reduction rate was good.COD decreased in the process of nitrification and denitrification of SBR,and increased when 0.3mL ethanol was added as an extra carbon source before denitrification,so there was little change before and after the reaction in general.?2?During ASBR's anaerobic process,ammonia decreased slightly,while during SBR nitrification,the average initial ammonia content was 19.2 mg·L-1,the average nitrification content was 8.0 mg·L-1 at 0.5h,and 2.8 mg·L-1 at 1h.The average removal efficiency was85.2%at 1h.?3?The content of nitrate in the inlet water of ASBR and SBR is low.Among them,in the anaerobic reaction of ASBR,the nitrate content decreased from an average of 3.8 mg·L-1at the beginning of the reaction to an average of 1.8 mg·L-1 after the reaction 4d.In the process of SBR nitrification,the initial nitrate content averaged 2.0 mg·L-1,rose to 4.6 mg·L-1 after0.5h nitrification,and 7.9 mg·L-1 after 1h nitrification.The average denitrification decreased to 2.9 mg·L-1 at 1h and 2.3 mg·L-1 at 2h.?4?Total nitrogen is decreased continuously in the ASBR-SBR combination process.The total nitrogen content of ASBR's inlet water is averaged 109.3 mg·L-1,then 92.5 mg·L-1 after1d,76.2 mg·L-1 after 2d,65.2 mg·L-1 after 3d,and 61.7 mg·L-1 after 4d.The total nitrogen content of SBR water was 31.4 mg·L-1 on average,which rose slightly to 33.9 mg·L-1 after 1h of nitrification,and then continued to decrease during the denitrification process,and decreased to 23.5 mg·L-1 after 2h of denitrification. |
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