Bacterial Diversity And Activation Research Of Algae Microbial Agents

With the acceleration of urbanization and the rapid development of industry andagriculture, the content of nitrogen and phosphorus are over high in the water.The algagrows crazy, resulting in water degradation, lower water clarity, changing the dominantpopulations and reducing the biological diversity, which has a serious impact on waterlandscape and human life. Meanwhile, eutrophic water cannot be used directly, furtheringwater crisis. In2012, our test of water environment result shows that, the national waterquality is generally stable, but the situation is still grim. Therefore, applying the efficientmicrobial technology without secondary pollution to repair eutrophication has a significancefor the safety of water environment and the entire ecosystem.This paper continuously utilizes the algaecide microbial agents (IBC) to treat theeutrophic water, which is an economic, efficient, and no secondary pollution technologyinhibiting the algae growth. PCR-DGGE technique is used to make an analysis of thecommunity of IBC. It studies the activation conditions before using IBC in order to improvethe efficiency of the IBC algicidal, thereby saving costs. Meanwhile, the algicidal effects ofthe activated IBC and non activated IBC are compared and the algicidal mechanism isdiscussed preliminary, providing a technical support in the practical application ofeutrophication. The conclusions are as follows:(1) It is obtained a DGGE fingerprint by PCR-DGGE, showing12different bands whichmeans that the algaecide microbial agents has abundant bacteria species diversity. There arefour darker bands, indicating that although the algaecide microbial agents is in a largenumber of bacteria species, there are still some dominant populations exit.(2) The results of brown sugar, urea, dissolved oxygen affecting the activation of IBCshow that with the growing number of brown sugar and urea, the viable bacteria number isincreasing, while the dissolved oxygen has a little effect. The result of these three factorsorthogonal experiment conducting a comprehensive activating factor show that the urea is thebiggest factor, followed by brown sugar, dissolved oxygen is the smallest factor. Under thecondition of urea0.0225g/g IBC, brown sugar0.0225g/g IBC, and speed80r/min(dissolvedoxygen is5.2mg/L), IBC reaches the maximum number of viable bacterium cells. And thenumber is8.7108cfu/g, increased by two orders of magnitude.(3) According to the activation orthogonal experiment, there come out to threeexperiment (4,6,9) having a good algicidal effects. After activation, the alga removal ratesare21.59%，29.29%，22.85%respectively; Chlorophyll-a removal ratios are14.8%， 25.7%and19.8%respectively; NO3--N removal ratios are99.03%，99.88%and99.84%respectively; NO—2-N contents are with no obvious changing；NH4+-N removal ratios are45.01%，58.97%，54.15%respectively; TP content of the experimental groups with anupward trend. While, only in the first five days, the control group has an algicidal effect, thealgae removal rate is14.75%; The chlorophyll a content rises after the first five daysdeclining; The utilization of inorganic nitrogen are unstable, but TP is slowly decreased withthe extension of the experimental time of the control group.(4) When the alga removal rate reaches about30%, the dosage of IBC withoutactivation is2600mg/L, while reducing600mg/L after activation. It can save the dosage of600g/t, saving30%of the cost.