Test: Desalination - Civil Engineering (CE) MCQ

Tube settler is not a type of distillation plant. It is used for shallow depth sedimentation.

Coagulation is not used for desalination. It is done for removing the suspended impurities from water.

Multistage flash evaporator is the best evaporative desalinating method in which the efficiency of multistage flash evaporator can be further improved by the use of flash enhancers.

Multistage flash evaporator produces 20 kg of water per kg of prime steam.
They operate on the brine recycling basis.

Reverse osmosis is more suitable for brackish water than sea water. In this process, some part of water permeates the membrane and is collected as fresh water while the remaining water passed through the turbine for recovery.

Multistage flash evaporator uses 69 stages in the desalination process. The vapors released during flash each stage condenses to heat the incoming sea water and gives fresh water.

In Electro dialysis, the salt ions are removed from seawater by means of electric current where two membranes are used- one who is more selective to anode and another who is more selective to cathode.

The process in which the brackish water is forced across a permeable membrane by mechanical forces is called as hyper filtration. The pressure applied must be greater than the osmotic pressure.

Desalination:

It can also be known as demineralization

• Desalination is the process of removing salts or other minerals and contaminants from seawater, brackish water, and wastewater effluent
• It is an increasingly common solution to obtain fresh water for human consumption and for domestic/industrial utilization.
• The main two types of desalination are membrane and thermal desalination

Reclaimed water:

• Water reclamation is the processing of wastewater to make it reusable with definable treatment reliability and meeting appropriate water quality criteria; water reuse is the use of treated wastewater (or reclaimed water) for a valuable purpose.
• ​Reclamation involves all processes to treat wastewater so that it can be  reused
• Reclaimed water is the source of desalinated water

In Electro-dialysis, the passage of electric current helps the diffusion of cation and anion permeable membrane and the energy required is directly proportional to the concentration of salt in the saline water.