|
The experiments on 48 Azotobacter flocculation ability were screened, and efficient flocculant-producing bacteria growing conditions, characteristics and practical application were studied, the results are as follows: From the 48 nitrogen-fixing bacteria, by screening obtained 14 has obvious flocculation strains, further rescreening, get two flocculant producing strain HY1141 and HY241. In determining the best strains tested carbon and nitrogen sources, based on the orthogonal experiment screened out best medium and optimal culture conditions. The results show that, HY1141 best carbon source is sucrose, the best nitrogen source for the N 2 ; optimum medium for sugar 5g / L, potassium dihydrogen phosphate 1.5g / L, magnesium sulfate 0.6g / L; optimal culture conditions for the speed of 150 r / min, the culture temperature 35 ℃, initial medium pH 7.0, incubation time 36 h; Under this condition, the bacteria produce flocculant flocculation of kaolin suspension rate was 96.4 %. HY241 The best carbon source was sucrose, the best nitrogen source is ammonium sulfate; best medium for sugar 5g / L, ammonium sulfate 1g ╱ L, potassium dihydrogenphosphate 1.5 g / L, magnesium sulfate 0.5g / L; the culture conditions were good speed 180 r / min, culture temperature 30 ℃, medium initial pH7.0, incubation time 48 h; Under this condition, the bacteria produce flocculant flocculation of kaolin suspension rate was 96.6%. Flocculation findings show: two flocculating activity are derived from bacteria cells secrete extracellular metabolites, the flocculant has good pH stability and thermal stability. HY1141 to acidic water treatment is better, HY241 neutral acidic water treatment is better; two strains produced the optimum dosage of flocculant are 4mL / L; HY1141 and HY241 required CaCl 2 optimal concentrations were 0.5% and 1.0%; optimum flocculation time was 5 min and 10min. The chemical composition of the flocculant were analyzed, the results showed that: the main component flocculant polysaccharides. In practical applications, the two strains produced flocculant for water treatment of raw water is better, which had the best effect HY241, flocculation rate of 92.8%, COD removal rate of 85.0%; addition, produced by the two strains flocculant for floods and beneficiation wastewater treatment have some effect, and HY1141 handle floods better, mix dressing wastewater treatment flocculant better. Through the strains were identified, belonging to Azotobacter HY1141 results, HY241 belong Enterobacter.
|