The Immobiliztion Of Bacillus Megaterium And The Remediation On Monosultap Contaminated Soil

The immobilization of Bacillus megaterium and the remediation on monosultap contaminated soil were studied in this paper. It included the following parts:1. Probit method was used to calculate the acute toxicity test of the earthworm against monosultap in filter paper method. The results showed that LC50 of 24 and 48 hours were 32.69 mg/cm2 and 15.00mg/cm2. LC50 of 7 and 14 days of the earthworm against monosultap were 110mg/kg(dry soil) and 43 mg/kg(dry soil) by artificial soil method. Monosultap was low-toxic pesticide according to the partition of pesticide toxicity in laboratory and of toxic coefficient in field .2. Bacillus megaterium isolated from mud was cultured and domesticated. By orthogonal experiments, the optimized temperature 30℃and PH value 7 were concluded. Growth periods of Bacillus megaterium were tested. Lag phase, log phase and stationary phase were approximately 10, 16 to 48 and 24 hours. And then decline phase would occur.3. Based on three orthogonal experiments, optimized immobilization process was determined. 0.01g diatomite was added into 15ml carrier mixture made of two times of 1.5% sodium alginate and 10% PVA. Other factors had weak effects.4. Degradation experiments were carried out by uniform design. Kinetics equation of target reaction was established by regressive analysis if time and concentration were included in the variables. The experiment results showed that degradation capacity of immobilized cell was better than that of free cell. Kinetics equation of degradation reaction was determined by establishment and simple transform of mathematics model of which by means of multiple element stepwise regression analysis. The original concentration and degradation time of monosultap were discussed as significant factors of effect on degradation process. Experiment results showed that the higher the original concentration of monosultap was, the more disadvantageous degradation of immobilized cell was. And degradation rate and superiority of immobilized cell were higher and obvious than free cell along with degradation time.