Application Of Compound Microorganism Producting MBF In Treating Leather Water

Traditional flocculants have been used widely due to their low prices and good effect. However, their disadvantages have drawn people's attention. Aluminium remained in drinking water easily leads to senile dementia. The monomer of polyacrylamide (PAA) can't be degraded and it's both neurotoxic and oncogenic for human body. Thus, which is safe and biodegradable macromolecular flocculants secreted by microorganisms should appears. Their degradation products are harmless to the environment and humans. The development of a new biodegradable bioflocculant with strong flocculating activity is needed. In the late 1980s, Microbial flocculants have attracted more and more researchers'attention.The paper introduced the flocculants, their development and application in treatment of wastewater. Based on those, we had studied about microbial flocculants from the follows.Four flocculant-producing moulds were isolated from activated sludge which treated tannery water samples by an agar plate culture using four mediums, peptone culture, Czapek culture, Gao-1, PDA. A kaolin suspension was used as a flocculation test material. By observing those moulds with microscope, analysising and selecting, we found that those four moulds belong to aspergillus, their flocculating rate are respectively, 70.6%, 70.2%, 78.8% and 71.3%.Based on EM technical principle, after testing many compound experiment, we can draw a conclusion that after flora 1 and flora 3, flora 2 and flora 4 being compounded, the flocculating activity of flora would make higher. They were named MBFâ… and MBFâ…¡, their flocculating rate were respectively 84.4% and 86.9%. Next, by changing the contents of culture medium and conditions of culture and so on, through doing orthogonal experiment, we got a combination of cultivation that had the best effect of cultivation. The optimal Culture conditions of compound floraâ… were as follows, twenty four hours, pH eight, sucrose, NaNO3. The optimal Culture conditions of compound floraâ…¡were as follows, twenty four hours, pH eight, glucose, urea.We got raw product after extraction MBF by organic solvent. Then its composition was determinated by series of biochemical responses, The results showed that the flocculant contained polysaccharides, proteins and other macromolecules. The next we analysed its flocculating mechanism. The chroma, turbidity and COD of tannery water were decreased significantly after processed by these flocculant After treating dyeing wastewater and tannery wastewater by MBFâ… and MBFâ…¡, the removal rate of chroma and turbidity can exceed 70%, treating synthetic tannery water, the removal rate of COD can reach over 90%, the treatment effect is remarkable.