| The drilospheres is an important place where the earthworm interacts with thesurrounding environment, through the earthworm treatment sludge, the insoluble organicmatters can be degraded into the soluble organic matters which absorbed by plants andmicroorganisms, changing the number of microorganisms and population structure. Thevermicompost in the drilospheres rich in a great number of microorganisms, nutrients, etc.,can be used as good carrier for the growth and metabolism of microorganisms. Currently, wedid many research on vermicompost agricultural, whereas did litter research on mixing it withsludge and degradation directly. Based on this, the paper researched mainly on degradationeffect of vermicompost mixed with sludge, exploring transformation and effect ondegradation rate of nitrogen and phosphorus in the matrix at this process. This paperdiscussed in these aspects on the change in physical and chemical properties, nitrogen andphosphorus mineralization and its correlation with related enzymes of the matrix, providingsome theoretical basis and practical guidance for applying vermicompost for the subsequentsludge degradation and agriculture.Vermicompost produced in incubating earthworms at our testroom and dewatered sludgeproduced in wastewater treatment plant at this area were raw materials for this paper,including control group and test group of three test groups.We take the composting test atconstant temperature and humidity conditions after the stability time for7days.We fliped iteveryday to ensure ventilation, taking7day as a cycle test and six samples totally. The testresults are obtained as follows:1, Vermicompost containing large amounts of microorganisms mixed with sludge canpromote and activate the activity of microorganisms in the sludge, accelerate matrixmineralization of nitrogen and phosphorus and increase the content of mineral nitrogen,available phosphorus.That demonstrated the verimcropost had positive effects on degradationof sludge.2, In the test group,the pH,EC, moisture and organic matter had significant changes thanother test groups:the decline of pH is biggest, fell by9.42%,compared with the initialmatrix.The increase of EC showed that the mineralization of matrix were higher,the final ECwas up to3030μs·cm-1,the increase rate were nearly higher15, comepared with the controlgroups.Moisture content also declined,decreased by10.59%.But the organic matter contentdecreased less.3, The variance analysis showed that there were significant correlation (P<0.01)between the vermicompost and time and interaction of the two points and the variousindicators (except for ammonium).Vermicompost factor had greater effect (more than50%)on various indicators excepting for ammonium.Overall,the main contribution factor wasvermicompost.4, In the test group,nitrate content had increased significantly,an increase of77.79timeshigher than the first day of the experiment, the cumulative rate was up to61.54mg·kg-1·d-1.But nitrate content had not changed in the control group.It showed that thegrowth and metabolism of nitrifying microorganisms were significant,which promotedactively the nitrate accumulation in mixed matrix.5, The content of mineral nitrogen and available phosphorus presented the mineralizationdegree of matrix of nitrogen and phosphorus.The nitrogen content had a significant increase atthe12th day in the test group, the increased rate of86.02mg·kg-1·d-1,and availablephosphorus content had also increased55.50%at the end of compost.It shown that the mixedform had contribution to transform nitrogen and phosphorus to easy-to-state (mineralnitrogen,available phosphorus) and improve the bioavailability.6, The decline of the content of total nitrogen and total phosphorus showed the loss ofthe matrix of nitrogen and phosphorus.During the test,the amount of total nitrogen decreasedleast in the test group, the decreased rates were1/25compared with the control group.And thetotal phosphorus content decreased most in the test group, the decreased rates were11.16compared with the control group,respectively.It showed that the addition of vermicompost inthe degradation process still can not prevent or inhibit the loss and decrease of nitrogen andphosphorus nutrients.7, There were correlations among the physical and chemical properties,the relatedenzymes and nitrogen and phosphorus forms,which impacts among them weremutual.Correlation analysis showed that there were significant (P<0.01) correlation betweenorganic matter or EC and other indexes,between moisture content and various nitrogen forms,protease,urease, available phosphorus,phosphoric acid enzymes,and between pH and variousnitrogen forms, protease,urease,phosphatase room.In terms of related enzymes,there werehighly significant correlations (P<0.01) beween the protease and total nitrogen,ammoniumand nitrate,between urease and total nitrogen,nitrate nitrogen and mineral, but the correlationswas not obvious in others.In addition,the correlation between protease and urease was alsosignificant (P<0.01).This experimental study mainly reveals that the vermicompost had an influence on thetransformation and mineralization of nitrogen and phosphorus in the degradation process ofsludge and had actively promoting effect in the sludge degradation. The effective nitrogen andphosphorus (mineral nitrogen,available phosphorus) and EC were significantly increased, thedecreased of matrix moisture, pH and organic matter content made the matrix more stable, thus effectively achieving the "three" sludge disposal requirements. This research provides anew direction for further study and using of vermicompost, having a certain reference value. |
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