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Wastewater Story — Science STD 7 — Question

Gujarat BoardEnglish MediumSTD 7ScienceWastewater Story5 Marks
Question
Given below is a jumbled sequence of the processes involved in a wastewater treatment plant. Arrange them in their correct sequence.
(i)Sludge is scraped out and skimmer removes floating grease.
(ii)Water is made to settle in a large tank with a slope in the middle.
(iii)Large objects like plastic bags are removed by passing wastewater through bar screens.
(iv)Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.
(v)Wastewater enters a grit and sand removal tank.
✓

Answer

The correct sequence of wastewater treatment in treatment plant is
(iii)Large objects like plastic bags are removed by passing wastewater through bar screens.
(v)Wastewater enters a grit and sand removal tank.
(iv)Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.
(ii)Water is made to settle in a large tank with a slope in the middle.
(i)Sludge is scraped out and skimmer removes the floating grease.

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