| The benzoate wastewater riched in benzoates. The compounds are often used as materials in food, medicine, plastic, dyes and so on. If the wastewater released without disposed, it will pollute the environment. So many studies have been done and so long time have spend on it. But most of the studies focus on separating the microbes which can decompose the benzoate. The application of the microbes separated from the environments is not ideal. So the study about the decomposing of the benzoate is still a hotspot. In this study, the microbial degradation with hydrolytic acidification-aerobic process was investigated to treat the benzoate wastewater produced in chemical factory.1. The sludge was cultured successfully and the treating condition was also optimized. The biodegradability (BOD5/COD) of the benzoate wastewater could be raised from 0.26 to 0.44 by hydrolytic acidification. The hydrolytic acidification-aerobic process results in good removal of COD with 91.1% from 1350mg/L to 120mg/L and the wastewater could released according to the standard.2. Different sludge cultured with different substance have different abilities to bear the shock loading. When testing the sludge, we also find that the COD could be removed effectively and the benzoate shocks also cannot deteriorate the sludge cultured with benzoate or the nitryl-benzoate. We observed a breakdown with the sludge when the Nitryl-benzoate shocks. But the sludge cultured with benzoate was not. We think that both the COD and the ability to resist the shock loading are the important indexes to evaluate the sludge. The different response to the shock loading resulting from the nitryl-benzoate tell us that there are great difference between the two sludge treated with different substance. This shows that the ability removing the COD is not the only index to value the sludge. When fluctuating, the ability to bear the shock loading is the important index to estimate the sludge.3. DGGE is applied to compare the microbial community between the two sludges. The electrophoresis reveal the obvious difference. The electrophoresis show that the there are great difference between the two sludge and the microbial community is so complex. Only 7 and 8 kinds of pure cultures are got in the plate, and the dominant microorganisms are Pseudomonas sp. and Acinetobacter sp. in System I(cultured with benzoate), Pseudomonas sp. and Achromobacter sp. in System II(cultured with nitryl-benzoate).4. ARDRA was used to analyze the microbial community in the two sludge. The results revealed great difference between the two sludges: About 20.4% of the fingerprintings are special in the system I and 24.3% in the system II .103 and 107 kinds of fingerprintings are get by ARDRA. Theresults also show that the dominant microorganisms were Pseudomonas sp. and Thauera sp. in System I , Uncultured bacterium and Cytophaga sp. in System II.5. From the results getting from the DGGE and ARDRA, we can say that DGGE is so quick and sensitive and ARDRA is impersonal and completely. The molecular methods is so strict in technology and the cost is so high. The methods and the results got from the molecular methods only can be used in the laboratory until now. Compared with the cultivation-dependent method, DGGE and ARDRA can avoid the selectivity and are more appropriate to reveal the microbial community. When some limitations conquered firstly to get the better results, the molecular methods are appropriate to analyze the community structure in ecology. |
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