低溶气压力下微藻细胞的气浮法采收

Harvesting microalgal cells by dissolved air flotation under low saturation pressures

从理论和实验两方面探讨了通过添加微量表面活性剂以实现在较低溶气压力下进行微藻气浮采收的可行性。结果表明 :添加适量的非离子型表面活性剂Tween 2 0可降低待分离体系的表面张力 ,改善微气泡的质量 ,在较低溶气压力下 (≤ 0 .2 5MPa)可获得良好的采收效果。无论是批式过程还是连续操作 ,当溶气水中含有浓度为 10 0mg/kg的Tween 2 0时 ,采收性能都得到较大改善。

As a new and effective solid/liquid or liquid/liquid separation process, dissolved air flotation techniques had been widely used in the treatment of industrial wastewater for the removal or separation of oil, microorganisms and other ultra fines. A main disadvantage of the process was the high cost of water saturation required for high quality bubble formation. The possibilities of harvesting microalgal cells with Spirulina as a model by DAF under low saturation pressure (≤0.25 MPa) by adding low concentration of surfactant Tween 20 were dealt with the theory and experiments. The results showed that not only the bubble generation was possible at working pressure lower than ≤0.25 MPa by lowering the surface tension, but also the residual cells concentration in the flotation tower and the harvesting rate were much lowered and improved respectively.