| dc.description.abstract | Domestic wastewater contains ammonia nitrogen substances and organic acids, among which ammonia water, propionic acid and butyric acid often cause pungent odors. However, the method and process of degrading ammonia nitrogen substances and organic acids are cumbersome, and if they are not properly treated, and straightly discharged into the sewer, which will have a negative impact on the environment.
Bacillus subtilis is a Gram-positive bacterium that belongs to the Bacillus family. It is a bacterium that widely exists in the natural environment and is highly heat-resistant and capable of forming spores to adapt to harsher environments. Bacillus subtilis has a variety of metabolic pathways, which can metabolize pollutants such as organic matter and nitrogen sources, and convert them into harmless products.
Therefore, in this experiment Bacillus subtilis BCRC10029 is used as a method to treat domestic wastewater. By adding 10% (v/v) of the bacterial suspensions to a concentration of 0.1M ammonia, propionic acid, butyric acid and the mixed solution of the above three, a sample is taken every 24 hours for a total of 7 days, and the change of ammonia nitrogen content with the number of days was detected with a spectrophotometer, and the content of propionic acid and butyric acid with the number of days was detected with a gas chromatograph.
The experimental results show that no matter the content of ammonia nitrogen or the content of propionic acid and butyric acid, after fermentation with Bacillus subtilis BCRC10029, the contents of the three all have a downward trend with the increase of days. Under the best environmental conditions, Bacillus subtilis BCRC10029 The ammonia nitrogen consumed by the degradation of Bacillus subtilis BCRC10029 decreased by 84.4%, propionic acid was degraded and consumed from 3.54% to 0%, and butyric acid also decreased from 36.1% to 15.4%. In the mixed solution, the changes of ammonia nitrogen were 56.9%, 52.2%, 65.9% and 58.8% when inoculated with different bacterial concentration from low to high. The degradation and consumption of propionic acid by different concentrations of bacteria suspensions, the residual amount of propionic acid tended to 0 on the 7th day of fermentation, while the residual amount of butyric acid also decreased to a certain extent, showing that Bacillus subtilis BCRC10029 has the ability to degrade and consume ammonia nitrogen, propionic acid and butyric acid. | en_US |