| The rapid development of animal husbandry in Xinjiang has brought a lot of manure resources.Aerobic composting can effectively dispose of the excrement produced in the process of livestock and poultry breeding.However,traditional aerobic composting still generally suffers from secondary pollution during the composting process,low compost maturity,and heavy metals.Shortcomings such as weak passivation ability.Based on a thorough investigation of the heavy metal pollution of pig manure in the Aksu area of southern Xinjiang,this study chose jujube biochar as a passivation agent and pig manure as a raw material to explore the physical and chemical properties,maturity,and the evolution of different forms of heavy metals in different treatment groups during composting.Process and passivation effect.The main research results and conclusions are as follows:(1)The content of Cu and Zn in pig manure is much higher than that of other heavy metal species.The coefficient of variation of heavy metals in pig manure and feed at different stages is higher than 40%,indicating that the amount of heavy metal added in feed varies according to the feeding methods of different manufacturers.Pig manure has a very significant relationship with Cu in feed,and the content of Zn,As,Hg is significantly positively correlated;pig manure in fattening period has a very significant correlation with Cu,Zn,Hg,Pb in feed,and the content of As is significantly correlated.There is no correlation between the various elements in sow feed and manure.Principal component analysis shows that the source of heavy metals Cu,Zn,Hg,As in pig manure is mainly feed.Through the analysis of the various forms of heavy metals Cu and Zn in pig manure,it can be found that the effective state content exceeds 85%,which has a higher biological content.Effectiveness and mobility,the main heavy metal elements that limit the agricultural use of pig manure in Aksu area are mainly Cu,Zn and Hg;(2)The treatment group added with jujube biochar changed with the composting time.The temperature,p H value,and electrical conductivity showed a process of first increasing and then decreasing and then stabilizing.In the 0-14 days of composting,add jujube biochar.The moisture content of the compost decreased slowly and not much.The moisture content of the control group dropped rapidly after the 7th day,and the moisture content of each treatment at the high temperature stage decreased significantly.The water content of the treatment with jujube biochar began to drop significantly on the 14 th day,Until the end of composting.The F3 treatment group significantly increased the stack temperature and seed germination rate.The more biochar added,the more serious the blockage of the biochar pores;(3)Through the evaluation of maturity and the evolution characteristics of DOM(a macromolecular organic mixture with complex structure and interaction produced by water-soluble organic matter and humification),it can be seen that the degree of humification of the pile changes with the composting time.Slowly getting higher.The gray clustering method evaluation results show that the F3 pile is completely decomposed by the 52 nd day,and the optimal treatment is the F3 treatment group;the use of fuzzy comprehensive evaluation shows that the optimal treatment is the F2 and F3 treatment groups;the TOPSIS method is used.The results showed: F3>F2>F1>CK on the 52 nd day,the best treatment was F3 group.The DOM degradation law of aerobic composting of pig manure is basically aliphatic substances>proteins>carboxylic acids,and the degradation of polysaccharides,carboxylic acids and lignins is synchronized,and the degree of maturity is closely related to the compost temperature.In the experiment,the F3 treatment group had the highest degree of compost maturity and the highest degree of humification;(4)In this paper,the addition of jujube biochar has the best passivation effect on heavy metals Cu and Zn,and the addition of 12% biochar is the best.When the Cu passivation effect is the best,it can reach 36.36%,and the passivation effect on Zn is the best.The time can reach 32.34%. |
