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The Study On Influence Of Hydrolytic Enzyme Activitys During Vermicomposting For Two Kinds Of Particle Size Sludge

Posted on:2016-03-13Degree:MasterType:Thesis
Country:ChinaCandidate:X Y ZhangFull Text:PDF
GTID:2271330464974525Subject:Environmental Engineering
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The sludge of treated sewage is another big waste, improper handling can cause secondary pollution. Earthworms can make sludge treatment sludge waste into treasure, to achieve value in use of sludge. Vermicomposting is decomposed in the synergy of earthworms and microorganisms sludge organic matter, improve sludge mineralization traits and make it harmless. Make sludge to particle is good for earthworms live better fit, increase the degradation rate of the sludge and increase the contact area between the sludge with oxygen to make sure fully aerobic composting, then can improve processing efficiency. Sludge composting is essentially all types of organic matter in the sludge so that it continues to hydrolysis of small molecules, microbes continue for subsequent oxidative decomposition, absorption and utilization in order to achieve its humification biochemical reactions. Since this process organic macromolecules carbohydrates, fats, proteins and other substances in the first step of degradation must hydrolase action of microorganisms be secreted, Therefore, the change in hydrolase activity studies can reveal the biochemical mechanism of microbial composting process essentially, By hydrolysis activity variation can grasp carbohydrates, fats, proteins degradation of macromolecules in the composting process, the realization of the future vermicomposting industrialization understand the extent of degradation for all kinds of organic composting process, improve the efficiency of composting is important significance.In this study, the particle sludge as compost material, and to make sludge into two kinds of particle size for vermicomposting, systematic study of the composting Process, Invertase, Urease, Protease, Lipase, FDA hydrolase activity and the variation of moisture content OM, EC, p H, MBC, DOC, NH4+-N, NO3--N values. With sludge as raw material composting experiment, separately to two factors(sludge particle size, the earthworm), two levels(5 mm and 14.5 mm size, add the earthworm, not inoculated earthworms) of 4 kinds of processing. The experimental results show that:1.Four kinds of treatment, the inoculated sludge earthworms and reduce the particle size can not change the course of sludge degradation trends hydrolase activity. Only the degree of hydrolytic enzymes have different effects on the activity level of each of the periods composting levels; by two-factor analysis shows, inoculated earthworms, decrease the sludge particle size both factors of Sucrase, Urease, Lipase, FDA enzyme five hydrolysis enzyme activity level change at different stage of composting show significant difference(p < 0.05); In addition, add the earthworms and reduce interaction generated from the sludge particle size effects, respectively to Invertase enzyme activity change(20~60d), Urease enzyme activity change(10~60d), the FDA hydrolysis enzyme activity change(20, 40d) have significant difference, and changes in the activity of Protease and Lipase have not reached significant level(p > 0.05).2. The process of vermicomposting for two kinds of particle size sludge, the five kinds of hydrolase activity, although individual fluctuations at different time periods of vermicomposting, but five hydrolases show varying degrees of change in the overall downward trend:At the end of the compost, the vermicomposting for 5 mm and 14.5 mm particle size sludge Invertase activity than the initial decrease about 82.6%, 61% respectively; Urease activity than initial reduced about 94.5% and 96.3% respectively; Protease activity than the initial decrease about 22.5%, 20.2%; Lipase activity than initial reduced about 76.5% and 74.1% respectively; FDA enzyme activity, respectively, compared with the initial decrease about 60.8%, 49.9%.3.Through correlation analysis, the results show that decreasing the sludge particle size have not change the correlation among various hydrolytic enzymes, And two particle sludge in vermicomposting process, 5 kinds of hydrolase activity exhibited correlation, Individual correlation coefficients between the enzyme activities up to 0.8.4.Through principal component analysis can extract the three principal component can reflect the vermicomposting process represented by information in the original 13 indexes. Each principal component evaluation compost quality influence of sequence is: PC1 > PC2 > PC3. And can be seen from the load factor, the five kinds of hydrolase activity in both particle size vermicomposting process have a higher weight, indicating the importance of hydrolase activity and influence in the vermicomposting5.The impact on physical and chemical indicators during vermicomposting for two kinds of particle size sludge:(1) After earthworms regulation, organic matter mineralization promote and enhance nitrification, promote the degree of biochemical reactions. Due to the decomposing organic matter during vermicomposting, microbial biomass carbon of a significant reduction. The ultimate removal efficiency of organic matter are 28.5%, 21%; Conductivity higher than initial 2.93 times, 2.63 times. NO3--N values were 153 times, 77 times times higher than initial; Slight increase in moisture content than the original; MBC and lower than the initial 97%, 87.88%. DOC content in the mid composting process have larger changes, at the end of vermicomposting its initial value fairly.(2) When reduce the sludge particle size, due to the increase of specific surface area, particle size of sludge aerobic digestion, 5mm sludge group p H(30~50d), OM(10~60d), MBC(20,40~60d), DOC(20~30,50d), NH4+-N(50~60d),was significantly lower than 14.5 mm particle vermicomposting group(p<0.05). the moisture content(in 10~60d), EC(10~60d), NO3--N(30~60d) significantly higher than 14.5mm particle vermicomposting group(p<0.05).6. By correlation analysis and hydrolase activity seen between the physical and chemical indicators. 5 kinds of hydrolytic enzymes and MBC、OM positively correlated, and Invertase, Lipase, Urease, FDA enzyme and MBC and OM into a very significant positive correlation(p<0.001),In addition, and EC(in addition to the 14.5 mm size sludge of Protease in vermicomposting), moisture content(except Protease) change into a significant negative correlation.The experimental results showed that reducing the sludge particle size has good effect to to enhance the efficiency on vermicomposting, the sludge mineral a positive role in promoting, and reduce the sludge particle size and the interaction effect of earthworm inoculation to the influence of individual index has significant differences, can further strengthen the extent of the composting process.
Keywords/Search Tags:Vermicomposting, Particle size of Sludge, Hydrolase activity
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