Effects of Bacteria and Accessories on Chicken Manure Compost

[Objective] In order to study the influence of bacteria and accessories of chicken manure compost.[Method] The experiment was conducted to investigate the changes of temperature,the quantification of Escherichia coli and the odor during chicken manure compost by adding sawdust,rice husk,yeast and lactic acid bacteria respectively.[Result] The results showed that：（1） The yeast group reached the highest fermentation temperature 67.6 ℃,which was 6.9 ℃ higher than that of lactic acid bacteria group,and the fermentation time of yeast group kept over 55 ℃for 16 days,which was 5 days longer than that of lactic acid bacteria group,both of which were better than that of control group（55.9 ℃,5 days）;（2）The highest fermentation temperature of sawdust group was 2.2 ℃ higher than that of rice husk group,and the fermentation time of sawdust group kept over 55 ℃ was 3 days longer than that of rice husk group;（3） The quantification of E.coli reduced from10^5 to 10^2per gram in both of the yeast group and the lactic acid bacteria group.The odor of the yeast group and the lactic acid bacteria group disappeared in the seventh day and the eighth day respectively.[Conclusion] The results showed that the adding of yeast and sawdust was the best condition for chicken manure composting in this experiment.

Biochar mitigates the biotoxicity of heavy metals in livestock manure during composting

The addition of biochar could mitigate the bioavailability of heavy metals during livestock manure composting.However,the main action mechanism of biochar,such as how it worked,was ambiguous.Therefore,in this study,materials(biochar,alkali modified biochar,pretreated cotton ball)were added by embedding with nylon mesh bags to explore the adsorption performance of added materials and its influence on the composting process.The results showed that embedded materials promoted the formation of humic acid and reduced the distribution proportion of bioavailable fraction of heavy metals during composting(Cu:at least 15.72%;Zn:at least 33.44%).The surface of biochar extracted from composting contained attachments,however,the attachment of heavy metal was not detected and functional groups on the materials did no change significantly.This indicated that the addition of biochar did not directly adsorb heavy metals.Most notably,the microbial network changed after embedding materials,and the succession of microbial community promoted the formation of humic acid.Ultimately,structural equation models verified that embedded materials promoted the formation of humic acid through stable microbial groups,thereby accelerating the passivation of heavy metals during composting.This study provides theoretical and technical supports for mitigating the biotoxicity of heavy metals by biochar during composting.