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Subject :NSO    Class : Class 7

How is bacteria usually used in sewage treatment?

ABacteria is used to speed up digestion of waste into harmless soluble substances.
BBacteria is used to remove pathogens in sludge before the latter is released into water bodies.
CBacteria is used to help heavier waste to settle for removal in sedimentation tanks.
DBacteria is used to sterilise sludge to ensure safe discharge into rivers and lakes.


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