Science - Water water treatment

____ percent of total water on the earth is the fresh water?

• 21.6

• 97.1

• 97.4

• 71

On the way of increasing the availability of water to overcome its shortage is?

• Unnecessary use of water

• Drip irrigation

• Rainwater Harvesting

• Leaking pipes

________ is the technique of watering plants using narrow pipes and tubes which deliver water directly to the plants.

• Rain water harvesting

• Planting and watering

• Bawaris

• Drip irrigation

What is rainwater harvesting?

• Collecting rain water directly and storing it in big tanks for later use

• Over drawing of ground water

• making rain water percolate into the ground

• supply of water through pipes

2 ways of rain water harvesting?

• Roof top rainwater harvesting

• rainwater harvesting from open places around the building

The wastewater treatment (or sewage treatment) gives us two useful products:

• wood

• biogas

• sludge

• Oxygen

Most of the solid organic matter (faeces, etc.) settles down on the sloping bottom of the sedimentation tank in the form of ____

• anaerobic bacteria

• sewage

• decomposes

• a sludge

waste water treatment plant

____ removes large pieces of rubbish from the waste water.

• grit and sand removal

• 1st sedimentation tank

• screening

• 2nd sedimentation tank

The processing of sewage to remove pollutants and make it harmless so that it may be disposed of safely in the rivers, etc., is called ___

• sewage treatment

• rainwater harvesting

• wastewater treatment)

• septic tank