Screening and flocculating properties of bioflocculant-producing microorganisms

Screening of bioflocculant-producing microorganisms was carded out. A strain that secreted excellent bioflocculant was isolated from municipal sewage using the spread plate technique, identified as Klebsiella sp. by the analytical profile index （API） identification system, and named A9. Several important factors that had an effect on A9＇s bioflocculant-producing and flocculating activity were studied. A total of 4 g/L Kaolin suspension was used to measure the flocculating activity of the bioflocculant from A9. It was found that maltose and urea were Ag＇s best carbon and nitrogen sources, respectively, and the flocculating activity of the flocculating agent from A9 was markedly increased by the addition of trivalent cations such as Fe^3＋ and Al^3＋; furthermore, the bioflocculant produced by A9 was most effective when the pH value was 6.0.

Flocculated unclassified tailings settling efficiency improvement by particle collision optimization in the feedwell

Efficient thickening of tailings is a prerequisite for the metal mine tailings backfill and surface disposal operation.The effective collision of ultrafine tailings particles in suspension with flocculant molecules is essential for flocs aggregates formation and settling.Unreasonable feeding speed and flocculant adding method will lead to the failure of effective dispersion of flocculant and high particle content in thickener overflow.In this work,the effect of turbulence intensity and flocculant adding method on floc size,strength,and movement characteristics are analysed.Aiming to solve the turbidity increased,a pilot-scale continuous thickening test was carried out.Taking a single particle and multiple flocs of full tailings as the research object,the particle iterative settlement model of flocs was established.The influence of turbulence intensity on collision effect is studied by tracking and simulating particle trajectory.The results show that in the process of single particle settlement,chaos appears in the iterative process owing to particle adhesion which caused by micro action.When the turbulence intensity is 25.99%,the maximum particle size of tailings floc is 6.21 mm and the maximum sedimentation rate is 5.284 cm·s^(−1).The tailings floc presents a multi-scale structure of particle-force chain system when hindered settling,and the interweaving of strong and weak force chains constitutes the topological structure of particles.The results are applied to a thicker in plant,the flocculant addition mode and feed rate are optimized,and the flocs settling speed and overflow clarity are improved.

Experimental research on Phanerochaete chrysosporium as coal microbial flocculant

The flocculation effect of the Phanerochaete chrysosporium on the coal slurry were studied by orthogonal experimental method in this study.The results of research show that the P.chrysosporium has a good effect on flocculating coal slurry.The optimum combination of the experimental is the P.chrysosporium,which is cultured in 2 days,mixed with 2 mL coagulant and 2 mL broth.The flocculant is a broken liquid with pH value of 6.The hightest flocculation ratio is 93.5%.The result of FTIR shows that the biological extraction of P.chrysosporium contains a lot of acidic polysaccharides that has the effect on flocculation.Microbial flocculant molecules and particles of coal slurry could be flocculated by‘‘absorption bridge’’.