Effects Of Chlortetracycline And Heavy Metals On Swine Manure Composting Process And The Impact Of Lime

Aerobic composting is an effective way to stabilization and resource utilization of animal manure,while antibiotics and heavy metals residual in livestock manure are the main factors restricting the recycle of animal manure.The high temperature of the composting process is able to kill hazardous materials and pathogens,as well as the conversion of organic material in the heap.Based on the pig manure as the raw material,and the sawdust and rice husk as a conditioner,pilot composting experiment were carried out.The influence of the existence of chlortetracycline on the composting process,microbial activity and the morphological changes of heavy metals were investigated.In addition,lime was added to see the effect on the process of composting,microbiological activity,and the degradation of the metal and the different morphological changes of heavy metals in the process of composting.Furthermore,the transformation of dissolved organic matter in the composting process was analyzed by means of spectroscopy and the composting products were evaluated according to the national standard of fertilizer.In order to examine the effects of chlortetracycline on the composting process and rot,3 sets of experiments with different chlortetracycline concentration [0mg·kg-1 DW(CK),10 mg·kg-1 DW(T1)? 50 mg·kg-1 DW(T2)] were conducted.The results showed that chlortetracycline impact on physical and chemical properties is mainly manifested in the temperature of the pile body.Combined with the change of the microbial enzyme activity in the composting process,the maximum temperature during the high temperature period was remarkable affected as well as the activity of hydrogen peroxide enzyme,protease,urease,cellulose,sucrase enzyme.As the compost reaction carried out,the inhibition was gradually reduced.Through fourier infrared spectrum analysis,it was found that carbohydrates and aliphatic compounds were reduced,but there is no significant changes on hemicellulose and cellulose.EEM spectra is a good method to describe the change of soluble organic matter during the composting.The humic substances and fulvic acid increase gradually in incipient stage,PI,n,PII,n and PIV,n were significantly reduced.Effects of lime on the composting process were explored.It found that the addition of lime can enhance the temperature of the heap,increase the initial pH.There was no obvious effect on catalase,beneficial effect on protease urease and enzyme.But there was inhibition on sucrose.In general,the presence of lime on the enzyme activity of microbes in compost not only promoted the activities of microorganisms,but also accelerated the process of the composting.Through the analysis of fluorescence spectroscopy combined with integral analysis,it found that the percentage of P?,n and PV,n were higher than T1.The existence of lime promoted the degradation of the organic matter and accelerated the composting process.In order to study the removal of chlortetracycline and heavy metals during the compost processing,aureomycin and heavy metals were measured during the composting process.Composting process can effectively remove the chlortetracycline residual from pig manure.In the first batch,no chlortetracycline was detected in CK,the antibiotics degradation rate of TI and T2 reached 96.31% and 96.31%,respectively.In the second batch,the addition of lime was beneficial to the degradation of chlortetracycline with shorter half-life period.There were interactions between degradation of chlortetracycline and biological available Cu and Zn.The addition of lime was found to promote the solidification of heavy metal Zn,but the effect on Cu was not obvious.