Question 20

Given below is a jumbled sequence of the processes involved in a wastewater treatment plant. Arrange them in their correct sequence.
(a) Sludge is scraped out and skimmer removes floating grease.
(b) Water is made to settle in a large tank with a slope in the middle.
(c) Large objects like plastic bags are removed by passing wastewater through bar screens.
(d) Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.
(e) Wastewater enters a grit and sand removal tank.

Given below is a jumbled sequence of the processes involved in a wastewater treatment plant. Arrange them in their correct sequence. ​

The process of removing large objects such as plastic bags, clothes, diapers etc using grills and nets in a wastewater treatment plant is called________.

Question 21

Three statements are provided here which define the terms, i.e. sludge, sewage and wastewater. Pick out the correct definition for each of these terms.
(a) The settled solids that are removed in wastewater treatment with a scraper.
(b) Water from kitchen used for washing dishes.
(c) Wastewater released from homes, industries, hospitals and other public buildings.