Study On Screen Of Microbioflocculant And Application In Wastewater Treatment

Bioflocculant has become a hot research respect in the field of environmental engineering since it is non-poisonous, non-harmful, easily bio-degradeable, and does not produce second-hand pollution and has good flocculating effect. There are quite a lots of researchs on bioflocculant at home and abroad. Bioflocculants can be produced by many types of microorganisms. However, few bioflocculants have very good flocculating effect and can be utilized on large scale. Besides, bioflocculants have many types and are of various flocculating characteristics. Therefore,systematic basic study are urgently needed so that the common features of bioflocculants can be summarized and the functioning mechanism can be studied. Currently, high production cost has been the main obstacle of bioflocculant application in practice. Screening of cheap culture media is therefore one of urgent projects in the field of bioflocculant research.Fifty-one strains of bacteria were isolated from activited sludge of Wangtang Factory of Wasterwater Treatment and Hefei Steel Factory in the thesis. Fifteen stains of bacteria have gained by principium screen. Four stains of bacteria have highest flocculant activity ,were named J1,J3,W1,W2. The bacterium was identified as Bacillus megetarium. The environmental facts are manipulated to investigate their effects during degradation bacterial colonies of incubation. The effects of time,temperature,acid and concentration of biomass on growth of the four strains have been studied.1 Study on the optimization raise condition of the microbioflocculant. In the experiment first carries on optimal the carbon-nitrogen which is the microorganism need. The process contrast experiment that selects the sucrose,the glucose to take as carbon;and the urea,the yeast paste to take as nitrogen. The raise condition selects pH,oxygenizement quantity,raise temperature ;carry on these four factors and four level experiments cross.Obtained J1,J3,W1 and W2 four kind of bacteria best raise conditions separately.2 To research the microbioflocculant influence factors,in the experiment has selected factors :C/N,different raise time,different pH,different temperature,different metal positive ion,oxygenizement quantity. Obtained a series of data, the flocculation rate of J1 bacteria achieved above 75% when C/N=1/2; that of J3 bacteria achieved 85% when C/N=1/1; That of W1 bacteria achieved biggest when C/N=1/3 ,no effect under other proportions C/N; that of W2 bacteria achieves biggest when C/N=1/4. Influence of different C/N is not big to J1,J3 bacteria, this two bacterias demand carbon much possibly. But carbon-nitrogen demanded more to W1,W2 bacteria,the two bacterias grow good under the sucrose-urea,separate exuberant,and nutrient fluid flocculation effect better.So carbon-nitrogen is sufficient, the mycelium can grow and separate the flocculant.J1,J3,W2 grow not well when little pH5.0, the flocculation rate is 0. When initial pH is 5.0 ~ 10.0, J1,J3,W2 grow good and the flocculant sepatare quantity is big. When the initial pH is 7.5 ~ 10.0, J1,J3,W2 grow exuberantly and the nutrient fluid sticks much, the flocculation rates are higher 80%.The W1 flocculation effect under the alkalinity condition is better than that under the acidic condition, when pH 7, the W1 flocculation effect obviously drops obviously,when pH=10, the flocculation rate approaches 0.The more obvious promoter action to the flocculation in high price ion which is Ca2+,A13+,the flocculation activity in PAC is better in the single metallic ion.3 Study preliminary on the flocculant microorganism, polysaccharide contents of J1,J3,W1,W2 are 84.3%,88.7%,84.85%,86.15%, this proved that the effective component of the four bacterias mainly is the polysaccharide.4 J1,J3,W1,W2 and PAC,PAM are operate contrast experiment in the single, processed effect is not difference.5 Selected the representative pond water,waste water of Wangtang Factory of Wasterwater Treatment,waste water of the Hefei brewery,waste water of the galvanization factory performs the simulation test, W2 to galvanizes the waste water the processing effect to be best, to Cu2+, Zn2+ removeing rate respectively achieved 30.60%, 29.13%, possible W2 to have the certain adsorption metal positive ion the ability. To in the waste water suspension is J3 which removes the effect to be best. The experimental result also indicated that, Regarding the different water quality waste water, the processing effect is different, its reason waits for the further research.