Study Of Therelease Effect Of Aerobic Composting To The Insoluble Phosphate

In this paper, by culture an Aspergillus niger isolated from the soil, to explore the strain effect to insoluble phosphate and soluble the phosphate mechanism.Then vaccination it into the aerobic composting, to explore the effect to the insoluble phosphate in the compost environment. Then from the point of the inoculation time, inoculation number to analysis the inoculated compost to the insoluble phosphate effect. The experiment results are as followed:The aspergillus niger strain mainly secreted the small molecules acids include oxalic acid, citric acids and a small amount of malic acid to dissolved the insoluble phosphate such as calcium phosphate in liquid fermentation environment. At the same time the phosphate added as a nutrient absorbed by the strain, involved in the metabolism of their own.By single factor experiments and orthogonal showed that citric acid to the phosphate-solubilizing is the best in variety of small molecule organic acid. In the case of low concentration, the phosphate solubilization condition for citric acid are:the concentration of 100mmol/L, the reaction temperature is 50℃, the initial pH is 3.5, the best reaction time is last 24h.The different phosphate-dissolving effect of different insoluble phosphate to the bio-waste aerobic composting. After experiment, the calcium phosphate and the iron phosphate effect is the best, followed is DCP, while the aluminum phosphate and phosphate rock is not significant.Add the cultured aspergillus niger to the bio-waste composting, the results shows that the available phosphorus content in the treatment not only added source of inorganic phosphate,but also inoculated the aspergillus niger is higher than the treatment which is just added the source of inorganic phosphate,not vaccinated aspergillus niger. At the end of the fermentation should be higher 1.60g/Kg, is about 1.4 times to the treatment without aspergillus niger. Shows that the strain can adapt the composting environment, and can effectively improve the composting phosphate solubilizing efficiency.Inoculated aspergillus niger during the different stages of the composting fermentation, the phosphorus leaching rate in the treatment which is intial inoculation should be higher 2.8% and 7.8% than the treatment inoculated in the high temperature period and the cooling period, is that the two treatments of 1.14 times and 1.52 times. So inoculated the aspergillus niger in the initial fermentation can enhance the efficiency of composting than inoculated in other stages.Respectively add 30g, 60g, 120g the carrier after the inoculated aspergillus niger into the 6Kg compost materials. After the end of compost fermentation , the phosphrous leaching rate in the treatment added 60g carrier should be increased by 5.0% and 3.3% than the other two groups. So just in the use of nutrient from bio-waste compost, add inoculation carrier should be controlled account for about 1% in the total compost materials when the inoculationg using solid inoculation manner.