Chicken Manure Compost And Effects Of Crab Shell On Heavy Metal Speciation In Compost

With the rapid development of China's planting,livestock and aquaculture,the quantity of crop straw,livestock and poultry manure and aquaculture waste is increasing,The soil heavy metal accumulation of a large number of chicken,crab shell and straw and chicken manure as organic manure disposal caused widespread concern and passivation.Aiming at the above problems,this study using crab shell chitin and chitosan as passivation agent,straw amendment of Chicken Manure Aerobic composting test,clear crab shell on chicken manure compost physicochemical properties and heavy metal speciation and bio availability of the influence,determine the amount of appropriate composting of chicken manure in the crab shell.Provide technical support to alleviate the harmless disposal of livestock manure,crab shell resource utilization and heavy metal pollution and improve the quality of compost efficiency,is a useful attempt to treat waste and waste.The results show that:(1)Using chicken manure and straw as the main raw material of compost,adding different proportions of crab shell(0%,5%,10%and 15%)composting test,4 groups of mixed materials and the results show that the different proportion of the crab shell does not affect the composting process.However,there are some differences in physical,chemical and fertilizer nutrient indexes.Adding 10%of crab shell as K10(chicken manure:straw:crab shell = 15:5:2)heating rate the fastest,reached the highest temperature above 50 ?,to maintain a long time;Adding 15%of crab shell as K15 of the 4 groups;the material by the composting process of its moisture content slowly decreased to about 30%,and eliminate odor.The pH values of the 4 groups were maintained at 6.6-7.6,which was suitable for microbial.reproduction.The EC value was lower than 4.1 ms/cm-1after composting,and the T value<0.6,reached maturity.The medium range effective nitrogen content of compost was 2-2.5g/kg.The available P content was in the range of 3.5?4 g/kg;the content of available potassium was 15.5?16 g/kg.The compost seed germination index of the 4 groups was significantly improved,and the oxygen consumption rate was consistent with the change of temperature.(2)The contents of Zn,Cu,Pb,Cr,Cd and other heavy metals in the 4 groups were increased after composting,but the content of was not higher than that of organic fertilizer.The effects of different proportions of crab shell on the 5 heavy metals in compost were different.The content of Zn was CK>K5>K15>K10 in turn,the content of Cu was CK>K15>K10>K5 in turn,the content of Pb was CK>K5>K15>K15 in turn,the content of Cr was K10>K5>CK>K15 in turn,and the content of Cd was K5>CK>K15>K10.(3)After composting,the Zn,Cu,Pb,Cr,Cd,and other heavy metals in the compost of the 4 groups were significantly changed,and the effect of passivation was better than that of the other 5 groups.However,the effects of different adding amount of crab shell on the variation of heavy metals were different.The use ofAKvalue comparison results of heavy metal speciation in Zn,CK,K5,K10 control group and K15?Kvalue were-12.4%,-12.4%,-5.04%and-6.85;the control group showed that the composting effect on the transformation of Zn form the most obvious,followed by K5 treatment.For the Cu control group CK,K5,K10 and K15 ?Kvalue were 4.49%,0.27%,-4%,-6.9%;group K15 showed that composting effect on the transformation of Cu form the best,the second was K5.For the Pb control group CK,K5,K10 and K15?Kvalue were-38.09%,-33.35%,-38.24%,-35.06%;group K10 showed that composting effect on the transformation of Pb form the best,followed by CK treatment control group.For the Cr control group CK,K5,K10 and K15 ?Kvalue were-3.6%,3.26%,-2.2%,4.51%;the control group showed that the composting passivation effect on Cr is best,followed by K10 treatment.For the Cd control group CK,K5,K10 and K15 ?Kvalue were-18.85%,-17.82%,-21.68%,-29.98%;group K15 showed that composting passivation effect on Cd is best,followed by K10 treatment.In general,the crab shell with different ratio in chicken manure(0-15%range)can meet the composting conditions,but the rising rate of temperature and duration of composting on a variety of indicators and the transformation of heavy metals,crab shell add 10%is ideal,but the types of heavy metals in different materials to be passive,should choose different the proportion of crab shell.