Biochar influence on the composting process and heavy metal passivation during cow manure,wine lees,and garden waste co-vermicomposting
In this study,we aimed at investigating how biochar supplementation impacts physicochemical parameters,microbial communities,and heavy metal fractions and distributions during the vermicomposting process.We performed vermicomposting experiments of cow manure,wine lees,and garden waste as raw materials,using Eisenia fetida for 60 days at 5% (weight ratio)and separately supplementing the mixed substrates with bamboo biochar,wood biochar,and corncob biochar.Our results indicated that the addition of the three biochar types increased the seed germination index,reduced C/N,promoted compost maturity,and enhanced the total nitrogen,nitrate nitrogen,and humic acid contents in the final composts by 10.74%-13.20%,41.91%-54.29%,and 26.22%-33.44%,respectively,compared with the control.Between different types of biochar,the addition of corncob biochar could increase the degradation rate of organic matter and total nitrogen content.Wood biochar supplementation exerted a more important effect by increasing the nitrate nitrogen and humic acid contents in the compost.The addition of the three biochar types increased microbial richness and diversity,especially increasing the abundance of lignocellulolytic microorganisms,such as Actinomadur,Ilumatobacter,and Saccharomonospora.In addition,the supplementation of the three biochar types enhanced the exchangeable-into-oxide fraction transforming efficiency as well as increased the passivation rate of copper and zinc by 11.87 and 5.87 percentage points,respectively.The 5% bamboo biochar treatment yielded the highest copper and zinc passivation rates,and bamboo biochar supplementation could promote copper and zinc conversion from the higher-activity exchangeable state to the stable oxidation state.The correlation analysis results indicated that the copper and zinc oxide components positively correlated with humic acid and lignocellulolytic microorganisms(P<0.05).This study demonstrated that bamboo biochar,wood biochar,or corncob biochar supplementation could enhance vermicompost maturity,improve bacterial community structure,and promote metal passivation.
corncob biocharheavy metalEisenia fetidabacterial community structuregreen waste
国家科技期刊平台
NSTL
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