The Effects Of Residuals Tetracycline Antibiotics Of Animal Use On Anaerobic Digestion Of Pig Manure

The large-scale development of farms has caused a enormous number of livestock and poultry manure to be disposed of and the residual of veterinary antibiotics in livestock and poultry manure.Biogas engineering is an effective treatment method that can produce energy of renewable and clean,as well as make high-quality organic fertilizer,and anaerobic digestion is key technology of biogas engineering.Then,whether the livestock manure with residual antibiotics can directly enter the biogas project for anaerobic digestion becomes a problem.This study investigated the effects of tetracycline antibiotics residues in pig manure on anaerobic digestion,and then found out the relationship between the highest concentration of residues in livestock manure and the initiation node of inhibition.It is clear that the problem of whether the livestock manure containing antibiotics are able to directly enter the biogas project.The specific research is as follows:(1)The effects of oxytetracycline on anaerobic digestion was studied.At 30±1,the concentration of oxytetracycline was 10mg/kg,50mg/kg,100mg/kg,500mg/kg,1000mg/kg and 2000mg/kg,and the swine manure batch anaerobic digestion test was carried out.The study found that oxytetracycline could promote the gas production of anaerobic digestion when the added amount of oxytetracycline was 0~1000mg/kg.When the addition amount reaches 2000mg/kg,oxytetracycline has a significant inhibitory effect on the gas production of anaerobic digestion.The beginning of inhibitory node of oxytetracycline on anaerobic digestion was between 1000 mg/kg and 2000 mg/kg and was higher than the highest residual concentration in pig manure(524.4mg/kg).Therefore,livestock manure containing the highest residual concentration of oxytetracycline could directly enter the biogas project for anaerobic digestion.(2)The effects of chlortetracycline on anaerobic digestion was studied.At 30±1?,the concentration of additional added chlortetracycline was 10mg/kg,50mg/kg,100mg/kg,150mg/kg,200mg/kg,250mg/kg,500mg/kg,1000mg/kg for the test of batch anaerobic digestion of swine manure.The study found that chlortetracycline could promote the biogas production of anaerobic digestion when the added amount of chlortetracycline was 0-150 mg/kg.When the addition amount reaches 200mg/kg,chlortetracycline has a significant inhibitory effect on anaerobic digestion.Between150 mg/kg and 200 mg/kg,the beginning node of inhibitory of chlortetracycline on anaerobic digestion was slightly larger than the maximum residual concentration in pig manure(139.4mg/kg).Therefore,the livestock manure containing the maximum residual concentration of chlortetracycline could directly enter the biogas project for anaerobic digestion.(3)The effects of tetracycline on anaerobic digestion was studied.At 30±1?,the concentration of additional added tetracycline was 1mg/kg,10mg/kg,50mg/kg,80mg/kg,100mg/kg,150mg/kg,200mg/kg,500mg/kg for batch anaerobic digestion test of swine manure.The study found that when the amount of additional added tetracycline was between 1 and 50 mg/kg,the inhibitory effect of tetracycline on anaerobic digestion was enhanced.At 50mg/kg,the inhibitory effect has reached basically stable and the effects of inhibition no growth.After that,the increase in antibiotics concentration still shows inhibition.When the concentration of additional added tetracycline is 1mg/kg,the anaerobic digestion is adverse.This concentration is much lower than the highest tetracycline residue in livestock manure(78.57mg/kg).Therefore,livestock containing residual tetracycline should not be directly added to the biogas project.Feces could inhibit the production and quality of biogas.Two-phase anaerobic can be used to reduce the effects of tetracycline toxicity on anaerobic digestion.In addition,add enhancer into anaerobic digestion,such as activated carbon,when adding feces.(4)The effect of doxycycline on anaerobic digestion was studied.At 30±1?,the concentration of additional added tetracycline was 10mg/kg,50mg/kg,100mg/kg,150mg/kg,200mg/kg,250mg/kg,500mg/kg,1000mg/kg for batch anaerobic digestion test of pig manure.The research found that when the additional added amount of doxycycline was 10 mg/kg,the inhibition of anaerobic digestion began to appear.After the increase of the concentration of another added doxycycline,the inhibitory effect was still observed and the inhibitory effect did not increase with the increase of doxytetracycline concentration,and the rate of inhibition was basically maintained at 60-70%.When the concentration of added doxycycline was 10 mg/kg,inhibition began to occur,and there was no comparable residual concentration.Therefore,it is not recommended to directly add the residual doxycycline to the biogas project.It can assist in the mixing and addition of enhancers on anaerobic digestion,or use two-phase anaerobic digestion to reduce the toxic effects ofdoxycycline.(5)Comparative analysis of the effects of tetracycline antibiotics on anaerobic digestion.Taking cumulative methanogenesis as an indicator,the order of strength of antibiotics inhibited: doxycycline > tetracycline > chlortetracycline > oxytetracycline.