Application And Research Of Cheap Culture Media Of Flocculant-Producing Bacteria

Microbial flocculant is a kind of new natural organic polymer compounds,featured with efficiency,safety and no secondary pollution,etc.On the basis of the present research and the development of microbial flocculants at home and abroad in recent years,this paper illustrates the selection of microbial flocculant,the research of optimizing fermentation condition as well as the choose of cheap culture media which aims to reduce the production cost of microbial flocculant.Besides that,the paper explores new flocculants oriented in the different wastewater through researching the flocculant structure and mechanism,in order to improve the efficiency of flocculation and scope and to achieve the purpose of using waste treat waste.Main content and the conclusions are as follows:Adopting domestic wastewater and activated sludge as bacteria source,in a particular culture media 56 strains bacteria was isolated.And after screening of kaolin suspension flocculation experiment,17 strains containning bioflocculant-producing bacteria were isolated.According to the size of the flocculating activity and the stability of flocculation measurement,the paper determines to adopt the sludge from w-3 strains which flocculating activity was as high as 63.22% as later experiment study.At the same time,based on the analysis of various morphological characteristics and physiological and biochemical experiments,this bacterium preliminaryly identified as aeromonas.W-3 are discussed in the conditions of the comprehensive optimization by using the method of response surface optimization,the optimum culture conditions were as follows: pH 7,culture under 31 ?,for50 h,141 r/min,and the flocculating rate was 74.61%.The paper adopted cheaper tofu wastewater,dairy wastewater,white vinegar,wastewater as cheap culture media to optimize.The Bean curd waste water culture conditions were as follows : pH 7,K2HPO4 0.05 g,under 31?,for 50 h,140 r/min,and flocculating rate was72.43%.The Dairy wastewater culture conditions wer as follows: pH 7,add glucose 0.05 gand 0.05 g CaCl2,under 31?,for 50 h,140 r/min and flocculating rate was 71.27%.The paper Combined P-B screening and the response surface analysis to apply for optimizing white vinegar culture medium conditions,and the optimum culture conditions were as follows : 140r/min,under 32 ?,for 48 h,pH 6.88,potassium hydrogen phosphate 4.08 g/L,ammonium chloride 2.39 g/L and flocculating rate was 75.66%.By choosing food wastewater instead of traditional wastewater as culture medium,the cost has reduced as well as achieving the purpose of using waste treat waste.By w-3 with white vinegar waste water culture medium preparation of microbial flocculant,the paper deal with practical papermaking wastewater.The flocculating rate can reach 97.89%,COD removal rate can reach 41.35% and the chroma removal rate can reach95.60%,which the flocculant dose was 4.5 ml,and coagulant aid dose was 6 ml,To deal with coal washing wastewater,the flocculant dose is 4 ml and coagulant aid dose is 4 ml which flocculating rate can reach 96.42%.To deal with electroplating waste water,dose amount is 2ml,wastewater pH 5 and coagulant aid dose is 5 ml,which flocculating rate can reach 79.46%.It can be seen that the microbial flocculant with good flocculation can deal with a variety of waste water.Producing flocculant to treat waste by waste water is feasible.After purification of flocculant,by Zeta potential changes in the process of flocculation and flocculant of sugar and protein detection,infrared spectrum analysis,the microbial flocculant negatively charged,belongs to the anion biological macromolecule flocculant,give priority to with sugar,basic does not contain proteins,has branched chain crosslinking structure,there are more adsorption sites and porous.Flocculation of kaolin,mainly polymer adsorption bridging between the trap effect is complementary,in the presence of Ca2+,such as high cation,compression colloid particles in the surface electric double layer,reduce the electromotive force,microbial flocculant of functional groups in the connection bridge between kaolin suspension particles,forming large flocs.