Development Of The Compound Bacteria Preparation And Its Application To Purifying Aquaeulture Wastewater

The pollution of aquaculture water is a severe problem faced by human being, and threatened the environment and aquaculture. Like deal with the other water pollution, biotreatment also is a chief choice for aquaculture water pollution. Many kinds of microbial preparation reported and produced for control the water pollution. Among them, compound bacteria preparations are well known for the higher physiological functions in purifying of wastewater. In this thesis, based on the removing ability to nitrogen, phosphorus and organic contamination, the functional bacteria were screened from the water, sludge and sediment in eutrophicated pond and piggery wastewater. The selected bacteria were cultured mixedly, and the function of mixed culture and the growth conditions of each strain were investigated. In addition, the method for production of the compound bacteria preparation was developed and the efficiency of the preparation was tested by treating eutrophic pond water. The main results were as follows:1Nine bacteria that have the potential to purify and improve polluted water were isolated from the samples collected in the contaminated pond water and sludge. It was found that the strains of PSB-B3, PSB-A6and PSB-A8can increase dissolved oxygen concentration in water with the highest amount up to3.49mg/L. Protease and amylase could be produced by strains K1, K2, K3and K4, the activity of enzymes reached to40U/mL after36hours cultivation. Strain NCG1was found to have high COD degrading ability with80.18%degradation rate in dealing with the artificial wastewater. Strain C-4showed higher aerobic denitrifying activity, and under the conditions of sodium citrate as carbon source, temperature30℃, shaking speed120r/min,200mg/L NH4+-N medium and100mg/L NO2--N medium, the net removal rates of nitrogen were65.8%and47.8%after15h and12h, respectively.2Based on the morphological and physiological characteristics, and the gene sequence of16S rRNA, strains PSB-B3, PSB-A6and PSB-A8were identified as Rhodopseudomonas palustris, strains K1and K4were identified as Bacillus subtilis, strains K2and K3were identified as Bacillus licheniformis, strains C-4and NCG1were identified as Acinetobacter sp. and Pseudomonas stutzeri, respectively. 3The synergistic effect of strains with the yeast and lactic acid bacteria kept in our laboratory was investigated respectively. Strains PSB-B3, PSB-A6and PSB-A8grow well with other strains; the strains NCG1, C-4, J-1were symbiotic with J-80; and K1, K4, J-1were symbiotic with J-80. From the analysis, we screened the microorganisms and divided into two groups to prepare compound bacteria preparation. The group A included PSB-B3, PSB-A6PSB-A8, NCG1and C-4while the group M included K1, K4, J-1and J-80.4In comparison with the single bacterium, the mixed microoganisms had high purifying ability in water purifying test. Synergistic effect in purification was found when NCG1used with C-4. The mixed two strains showed higher ability than single microorganism. The rates for the compound bacteria to remove ammonium, nitrite nitrogen and COD in72h were84.4%,86.91%, and81.36%, respectively.5The method for production of the compound bacteria preparation was developed and the efficiency of the preparation was tested by treating eutrophic pond water. The results indicated that the preparation could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample. After five days since the preparation was put into experimental ponds, the NO2-N and TP were not detected, both the content of NH4+-N and COD were less than2mg/L, and dissolved oxygen concentration in water increased by0.24mg/L, pH was stabilized at6.8～7.0. After six months of storage, the living cell populations in preparation do not change.