WATER TREATMENT

The rejection rate of a good RO membrane is usually:

• 40–50%

• 60–70%

• 95–99%

• 20–30%

Which pre-treatment is generally required before RO plant?

• Softener

• Multimedia filter

• Activated carbon filter

• All of the above

RO membrane is made of:

• Polypropylene

• Cellulose acetate or polyamide

• PVC

• Stainless steel

Which pre-treatment protects RO membrane from chlorine

• Softener

• Activated carbon filter

• Multimedia filter

• UV filter

Typical RO pressure for brackish water plants is:

• 5–10 psi

• 20–50 psi

• 500–800 psi

• 150–250 psi

Scaling in RO occurs due to:

• High chlorine

• High CO₂

• High hardness (Ca, Mg salts)

• Low pH

pH of RO permeate water is usually:

• 7.0–8.0

• 6.0–6.8

• 8.5–9.0

• 5.0–5.5

Which parameter is monitored online in RO plants?

• Temperature

• Conductivity

• Turbidity

• BOD

The main purpose of a water softener is:

• To remove suspended solids

• To remove bacteria

• To remove calcium and magnesium ions

• o remove dissolved salts

Water softening is mainly achieved by:

• Reverse Osmosis

• Ion Exchange process

• Distillation

• Sedimentation