Study on the Treatment of Domestic Sewage by Lactococcus

As a commonly probiotics, lactococcus produces a large amount of lactic acid during the growth and metabolism process, which can regulate the pH value of the environment. At the same time, lactic acid can also transform the refractory organic matter in sewage into degradable or easily degradable substances, thus accelerating the degradation rate of pollutants. The removal rate COD, TP and TN were selected as the test indexes in the experiment. The single-factor experiment was carried out first. Orthogonal experiments were carried out according to the result of single-factor experiment. Experiments showed that the optimal reaction time of COD, TP and TN removal was 54h/42h/24h, the optimal dosage was 9.00mL/4.00mL/9.00mL, the optimal pH value was 6.00/6.00/8.00, and the removal rate was 68.41%/80.04%/32.54% respectively. It can be concluded that the degradation efficiency of lactococcus on TP and COD is better, while the degradation efficiency on TN is worse.