A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these
A. Are water seals which prevent the entry of foul gases B. Are used to trap the rats entering sewers C. Dissolve the foul gases D. Create symphonic action to increase the quick disposal of sewerage
