Biological Flocculant MBF-28 Used for Gas Oil Wastewater Treatment

A novel bioflocculant-producing bacterial strain B-28 was screened from contaminative soils by gas oil wastewater. The optimum carbon sources, nitrogen sources, metal ions and initial pH were glucose, yeast extract, 2 ml 0.1% FeCl₃ and 6-8, respectively. And at the optimal couture conditions, flocculating activity reached its maximum flocculating activity of 97.2% at 72 h. This indicated that the bioflocculant MBF-28 was produced by biosynthesis during its growth. Composition analysis and FT-IR analysis showed that the biopolymer mainly contains polysaccharid. In addition, when take 2.0 ml 0.1% FeCl₃ and 1.5 ml crude fermentation liquid of strain B-28 to 100 ml gas field wastewater and pH of the system was adjusted to 4-6. The mixture was then performed under 160 rpm for 60s and slowly mixing speed of 40 rpm for 160s, and then kept still for 20-40 min. The removal of COD and chroma were 64.5% and 84.8%, respectively.