求翻译：将从活性污泥中分离筛选出的九种细菌分别投入实验，分别停留5天、8天、12天，与原水水样相比，水体COD、BOD5、总氮、总磷指标都有下降，但不同菌株的净化效果不同。是什么意思？

Nine screened bacteria isolated from the activated sludge respectively invested experiment, respectively, for 5 days, 8 days, 12 days, compared with the raw water, water cod bod5, total nitrogen, total phosphorus indicators have shown a drop in However, the purifying effect of different strains.

In the activated sludge separation filter bacteria out of the 9 experiments, respectively, and were put into just 5 days, 8 days, 12 days, and the water, as water, BOD COD 5, total nitrogen, total phosphorus, and indicators are a decline in the different strains of different purification effect.

Will separate nine kind of bacteria from the active sludge which will screen to invest the experiment separately, will pause separately 5 day, 8 days, 12 days, will compare with the original water water sample, water body COD, BOD5, the total nitrogen, the total phosphorus target will all have the d

Isolated from activated sludge filters out of nine types of bacteria into experimental, for 5 days, 8 days, 12 days, respectively, compared with samples of raw water, water COD, BOD5, total nitrogen and total phosphorus index has declined, but different strains of purification effect of different.

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