Screening Of Flocculants-producing Microorganism Strains From The Sewage

Bioflocculant is a kind of metabolites produced by microorganisms or their secretions, was biodegradable and non-toxic and no secondary pollution, and has been applied in water treatment. It is one kind of high-efficiency water treatment agent. In this paper, a new kind of high flocculant-producing bacterium was isolated from wastewater and identified by16S rDNA amplification, its flocculation conditions were also optimized. The main conclusions were as follows:1. In this experiment,47kinds of microorganism were screened from wastewater of Shenyang Fairy River Wastewater Treatment Plant and the Western Shenyang Wastewater Treatment Center by five commonly medium, one bacterium with best flocculation effect was screened, and preliminary identified as Sphingobacterium sp. N-7by its morphological, physiological characteristics and16S rDNA sequencing, its flocculation rate was almost above80%. This strain can culture easily and can grow into a single colony in1or2days.2. After the single-factor and orthogonal test, the fermentation condition were optimized as follows:initial pH7.5, temperature30℃, rotation speed170r/min. Three parallel experiments were done under the optimum conditions; the average flocculation rate was91.3%. This bacterium reached stationary phase after culturing32h, and had a maximum flocculating activity after culturing36h.3. N-7bacterium was put into7kinds of wastewater with1%CaCl2by different proportion and found that it had obvious flocculation effect in four different kinds of wastewater, especially in coal mine wastewater. It makes a theoretical basis for its industrial applications.