Microbial Flocculants Efficient Bacterium Screening, Cultivation Condition Optimization And The Application In Wastewater

Microbial flocculant produced by microorganisms in certain culture condition is organic polymer compound with flocculation activity, Compareing with the traditional flocculant, microbial flocculant which takes the advantage of efficiency, non-toxic, degradation etc, therefore, is value of research and application .This study separated and purificated 58 strains bacteria respectively from SuZhou SNP sewage plant sludge,graden soil,lakeside clay through dilute flat method and flat crossed method and inspected flocculation activity of kaolin levitation liquid which zymotic fluid worked on. After the preliminary screening and secondary screening tests of MBF produce bacteria, there is a plant can produce efficient MBF strains J-3. after physiological and biochemical appraisal, Strains identifing show that the J-3 strain is Kodamaea ohmeri,this is the first time to find Kodamaea ohmeri which can produce good quality microbial flocculant.Optimization of Kodamaea ohmeri's physiological condition, bacteria culture conditions: cultivating time is 66h, inoculating quantity is 8%, wave bed speed is 200r/min, cultivating temperature is 30℃, the initial pH value is 6; The best medium: Dextrose 20g, KH₂PO₄ 2g,K₂HPO₄ 5g, (NH₄)₂SO₄ 0.2g, NaCl 0.1g, urea 0.5 g, yeast anointed 0.5g, MgSO₄·7H₂O 0.2g, H₂O 1000ml, pH 6.0, the production of flocculant Kodamaea ohmeri was 2.15g/L,the cost was 0.188 yuan/L.When kaolin concentration is the 4g/L, dosing of the Kodamaea ohmeri bacteria flocculant quantity is 2mL/100mL, flocculation system pH value is 7, temperature is 30℃, coagulant CaCl2 (concentration 1%) is 4mL/100mL, the flocculation effect is best, flocculation rate reaches 95.6%. Its flocculation effect is better than that of PAM, flocculation effect and PAC quite, produce the chemical sludge less, through the composition analysis MBF-J3 for anion type polysaccharide flocculating agent.Through the study, a preliminary study was his vision of the Kodamaea ohmeri bacteria flocculant life sewage, livestock waste water, oil wastewater, including algae wastewater and printing and dyeing wastewater treatment results. Results show that: bacteria flocculant of Kodamaea ohmeri for turbidity and SS remove is good, removal efficiency for chromaticity is general and removal efficiency for COD is poor. For printing and dyeing wastewater treatment, joining PAC, PAM blends with can play better after using the decolorization.