Study On Development And Application Of High-efficiency Bioflocculant

Bioflocculant is a kind of macromolecular flocculant secreted by microorganisms. These kinds of microbial polymers are expected to be useful in flocculating wastewater due to their bio-degradability and the harmlessness of their degradation products toward humans and the environment. However, the bioflocculants identified so far in laboratories have not yet practically applied in industry because of their high cost and low productivity. In this study the screening of a new flocculant-producing strain which could produce bioflocculant in industrial offal, flocculating efficiency, flocculating mechanism and application were carried out.In this study, AspergillnsY-1 and AzotobacterJ-25 as high-yield strains were screened out. AzotobacterJ-25 could make full use of industrial offal, and the vegetal term was easily control. The bioflocculant produced by AzotobacterJ-25 were widely useful in the treatment of wastewater. So emphasis on study of AzotobacterJ-25 was placed.AzotobacterJ-25 could be cultivated in monosodium glutamate wastewater, and excreted abundant bioflocculant. Culturing experiment showed that the optimum pH was 6.0. The optimum growing and flocculant-producing temperature was 34#. The time of the best performance was after culturing 16-24h. The production of bioflocculant was parallel to the cell growth.The flocculating experiment showed that the volume of flocculant JMBF-25 to treating Kaolin clay suspension was small, and did not influence the wastewater quality. The suitable pH value was weak alkaline. Ca2+ and A13+ facilitated the flocculation activity of bioflocculant.Analytical experiments approved that the major constitutes of JMBF-25 were polysaccharide. There were -COOH and -OH in molecules. It had larger molecular weight, and its structure was linear. The mechanism of flocculating was mainly absorbing and bridging.The wastewater purification experiments demonstrated that the JMBF-25 had good purifying effect in the treatment of various wastewaters, especially in the treatment of petrochemical wastewater. And it could better improve the sedimentation of the sludge as well. In the treatment of the petrochemical wastewater, it should be associated with inorganic flocculant.