Degradation Of Tetracycline Antibiotics In Chicken Manure

Tetracycline antibiotics(TCs)are a kind of broad-spectrum antibiotics widely used in animal husbandry.TCs,as feed additives,are not completely absorbed by animals,and most of them are excreted with animal manure and urine.The application of livestock manure containing a large amount of antibiotics in farmland makes TCs accumulate continuously in soil,which not only affects soil microbial diversity,but also is absorbed by crops and eventually enters the human body.Long-term consumption of such crops will improve human resistance to antibiotics,which is not conducive to human health.In this paper,the removal of TCs from livestock manure was studied.Several degradants were selected to remove TCs during composting.The main research is as follows:(1)Adding sawdust and potassium permanganate in the composting process will increase the degradation rate of TCs.Adding potassium permanganate in the early stage of composting will cause the thermal decomposition of potassium permanganate,which is not conducive to the degradation of TCs.When 400 g sawdust was added,50 g potassium permanganate was added to 10 kg chicken manure during the fermentation cooling period(20th day),and the degradation rate of TCs was 89% after composting.(2)The addition of furfural residue will increase the acidity of the compost and delay the maximum temperature of the compost,but its rich organic matter will increase the compost temperature.Therefore,the addition of furfural residue not only improves the composting maturity,but also reduces the pH of the compost and promotes the degradation of TCs.The maximum degradation rate of TCs was 98% when 6 kg furfural residue was added into 10 kg chicken manure and 50 g potassium permanganate was added during the fermentation cooling period.After composting,the organic matter in chicken manure increased by 41%,and the total nutrients of N,P and K increased by 2.8%.(3)Biomass ash is alkaline.Adding biomass ash in the early stage of composting can increase the pH of chicken manure and reduce the composting temperature,which is not conducive to the removal of TCs.Under the condition of ensuring the normal operation of high temperature period,the degradation rate of TCs was increased by adding biomass ash during the fermentation cooling period.The degradation rate of TCs was 93% when 4 kg biomass residue and 50 g potassium permanganate were added into 10 kg chicken manure at the same time during the cooling period of fermentation.After composting,the total K in chicken manure increased from 3.4% to 13.1%.(4)The effect of Ca-Mg-P fertilizer on chicken manure is similar to that of biomass ash.Adding Ca-Mg-P fertilizer will increase pH and decrease composting temperature.Therefore,calcium magnesium phosphate fertilizer was added to the compost during the cooling period.The maximum degradation rate of TCs was 94% when 50 g potassium permanganate and 3 kg calcium magnesium phosphate fertilizer were added into 10 kg chicken manure during the fermentation cooling period.After composting,the total P in chicken manure increased by 3.5%.Potassium permanganate,furfural residue,biomass residue and Ca,Mg and P fertilizers selected in this paper have good degradation effects on TCs.Among them,potassium permanganate can be used with acid or alkaline degradants respectively.After composting,nutrients in chicken manure increased,and acid or alkaline organic fertilizers could be used for soil improvement.