The Study Of Bacillus Subtilis Producing Flocculant Condition And Water Quality Improvement

In this experiment, the main agents is Bacillus subtilis, and explore the optimal culture conditions of Bacillus subtilis. And explored the flocculant production capacity of Bacillus subtills in the laboratory situation. Meanwhile, explored the Bacillus subtilis flocculant influence on ammonia nitrogen, nitrite nitrogen and total phosphorus at different carbon and nitrogen inputs in water. Experimental results are as follows:I. Determine the optimal culture conditions Bacillus subtilis through single factor experiment:pH of 7, glucose dosage 2%, Ca2+ dosage 0.3%, installed capacity of 28g, inoculation amount of 12%, the optimal culture temperature is 30 ?. Optimal conditions by orthogonal test to determine the four factors of Bacillus subtilis cultivated as follows:pH of 7, Ca2+was 3%,inoculation amount of 12%, incubation temperature of 28 ?. When at this condition, the needs of the proliferation of Bacillus subtilis was best meet, which made the OD value reached 0.083.II. Design an experiment to explore the production situation of flocculant by the metabolism of bacillus subtilis. In the laboratory operations,the experimental results showed that, the flocculation rate in the largest level when the amount is 8?l, the ratio of pond water dilution is 1:4, and the flocculation time is 48h. Which means that under this condition, the flocculant production capacity of Bacillus subtilis is in the largest level. However, this experiment is still limited in the laboratory, which has some improvement on the water quality, the field operation effect was not known. And Bacillus subtilis flocculant was produced by fermentation in the laboratory after high-temperature sterilization, which means there no other bacteria interference. And mechanism of action, influencing factors and more conditions and requirements need further study.III. The influence on the water quality improvement from Bacillus subtilis from the difference of carbon and nitrogen sources showed that, no matter the changing the carbon and nitrogen sources, the content affect on ammonia, nitrite and total phosphorus was in the largest level in the first 4 to 5 days. Therefore, the water quality improvement capacity would reach the highest stage in the first five days, which is the medication peak periods. So in practice, in order to keep the production capacity of flocculant and the effect on water quality at a peak stage,the next vote bacteria should 1 to 2 days later than the medication peak periods. The experiment also showed that, without nitrogen and carbon source addition, Bacillus subtilis flocculant also play a role to improve water quality. In actual production, because of feeding ration, water will have surplus carbon and nitrogen, which can be supplied to the Bacillus subtilis in improving water quality.