RRB Group-D Model Paper 19 with answers for online practice

Filtration

• Filtration is a process used to separate solids from liquids or gases by using a filter medium that allows fluid to pass through but not solid.
• Filtration can be mechanical-biological or physical.
• It does not help in disinfecting water.
• If you want to disinfect the water you can boil it or you can use alum for chlorine tablets.

Boiling

• Boiling is used to kill pathogenic bacteria, viruses, and protozoa.

Chlorination

• Chlorine kills a large variety of microbial waterborne pathogens.
• Chlorination is the process of adding chlorine to the water to disinfect it and kill pathogens.
• Amount of chlorine required for water disinfection around 1-16 milligram per litre of water.

Coagulation

• Alum acts as an electrolyte that helps in settling the suspended matter in water.
• The process of adding alum to disinfect water is called coagulation.