Preparation Of Microbial Flocculant And Flocculanting Treatment To MDF Wastewater In The Assistant Of Microbial Flocculant

6 bacteria were collected from sample of activated sludge respectively from the streamlet in Nanjing Forestry University and wastewater conditioner in MDF industry. The experimental results showed that mixed stains had certain flocculating activity. During the 6 bacteria, there were two, which showed relatively higher flocculating activity, named M-1, M-2. For the convenience of the application to industry, the flocculating activity of M-1, M-2 and mixed stains were investigated during the culture process. The influence of C/N ratio on the bioflocculant production and the distribution of flocculating activity had been studied in detail in this research. Results showed that 80% flocculating activity existed in supernatant, and were much highter when C/N were respectively 10,20,2.5.The proportion of polysaccharide in flocculating production were separatly 65.4%,43.2%,41.5%, and protein were 15.3%,35.0%, 19.8%. The components and chemical configurations of bacteria's production were particularly inquired.To the appearances of infrared spectra, there were functional group ,such as,-OH,-COO- in the surface of flocculating production ,which showed that M-1,M-2 and the mixed stains were all anionic flocculant.The experimental results exhibited that M-1 showed high flocculating activity in the treatment of high SS wastewater (about 90%), on the contrary, while for low SS wastewater, for instance, the natural water body, flocculating activity was around 50%.In the second part of the experimentation, we paid mainly attention to flocculating treatment of MDF wastewater with M-1. The optimal conditions for M-1 in MDF wastewater treatment were obtained through orthogonal test. There were four major factors: flocculant dosage, stirring speed,flocculation time,stirring time. Influence degree was flocculant dosage>tirring speed>flocculation time>stirring time. The best flocculating activity was 94.2% at pH10. Particle size had significantly increased during the flocculation process.Zeta potentials of colloid and suspended particle were -13.3 mV(MDF wastewater),-23.1 mV(M-1),-6.19 mV(the supernatant after flocculation) ,which was a better description on flocculation process.