Effects Of Inoculation Of Cadmium-solubilized Functional Microorganisms On The Composting And Its Effeciency

With the increasing area of heavy metal contaminated soil,crop planting in China has been affected to varying degrees.Accumulation of heavy metals absorbed from soil by crops,and through the food chain,into the human body,causes a serious threat to human health.It is a common problem for researchers both at home and abroad to find a kind of repair technology which cannot destroy the soil ecological environment.Microbial inoculation technology is widely used in composting,at present,it is mainly focused on the study of the effect of composting,but the research on the treatment of heavy metal pollution by compost is not enough.The Aspergillus niger strains can produce citric acid and oxalic acid as functional bacteria,and the dissolving ability analysis,then and use it with previous screening decomposition bacteria composite functional bacteria,in different ways to access landscaping waste for aerobic compost,study on the effects of different inoculation methods on the effect of compost during composting,compost effect analysis of dissolved heavy metals in soil,and provide scientific basis for the functional development of compost.The experiment of Aspergillus niger produced organic acid to dissolve CdCO₃.During the experiment,0,50 and 100mg/L CdCO₃ were added respectively to analyze the citric acid and oxalic acid production by Aspergillus niger,and the dissolution of CdCO₃.The results showed that the citric acid and other organic acids secreted by Aspergillus niger could dissolve CdCO₃;CdCO₃ reacts with citric acid,which leads to the decrease of citric acid content in fermentation broth and the increase of pH value of fermentation broth,the dissolution of oxalic acid is less than citric acid,which results in the increase of oxalic acid accumulation in solution;without the addition of CdCO₃,the Aspergillus niger grew well and the citric acid in the fermentation broth was higher,and the acidity was stronger;with the addition of CdCO₃,the dissolution rate of Cd increased;In order to further investigated the dissolving ability,Aspergillus niger was used to dissolved in soil heavy metals.The results showed that the addition of different soil had different effects on the growth of Aspergillus niger and the dissolution rate of heavy metals,when the amount of soil was increased,the content of Aspergillus niger and the dissolution rate of heavy metals decreased;The best effect of soil addition was 11.68g;The effect of Aspergillus niger on the exchangeable,carbonate and oxide bound states of heavy metals in soil was significant,but the effect of the organic combination and residue state on the stability of soil was not obvious.Antagonistic experiments showed that there was no antagonism between the mature bacteria and the functional fungi?Aspergillus niger?,the best ability of dissolving heavy metals in soil by Aspergillus niger,and it was used to construct the composite functional bacteria.The results show that the composite functional bacteria inoculation composting can improve the composting temperature,germination index of seeds,and increase the number of fungi compost,composting activity,reduce the ratio of carbon to nitrogen,accelerate the composting process,early and late inoculation of compost was better.The compost extract had a certain effect on the heavy metals in the soil,and the leaching solution of Cd at the early and late stage was the best.The effects of different inoculation treatments on soil heavy metal Cd were different.The effect of non-inoculation treatment was weak,but the effect of the initial and late inoculation was the best,and the dissolution rate was 19.36%.