CHEMICAL PRECIPITATION (TOXIC & HAZARDOUS WASTE MANAGEMENT)

What is the primary purpose of chemical precipitation in wastewater treatment?

• Removing suspended solids

• Neutralizing the pH

• 
  Removing dissolved ions and heavy metals

• Adding minerals to the water

What is the purpose of pre-precipitation in chemical precipitation processes?

• 
  Enhancing precipitation efficiency

• Removing impurities before precipitation

• Increasing the pH of the solution

• 
  All correct

Which of the following ions is commonly removed through co-precipitation in water treatment?

• Na+

• Fe3+

• 
  Cl-

• HCO3-

Post-precipitation in chemical precipitation involves:

• Removing precipitates after the primary precipitation

• 
  Increasing the temperature of the solution

• 
  Adding precipitating agents after primary precipitation

• 
  Decreasing the pH of the solution

1. Hydroxide Precipitation

   Sulfide Precipitation

2. Carbonate precipitation

What is the role of pH in chemical precipitation?

• 
  pH influences the solubility of compounds and thus affects precipitation

• pH does not affect chemical precipitation

• High pH always leads to better precipitation

• Low pH always leads to better precipitation

The efficiency of chemical precipitation is influenced by:

• 
  Temperature and pressure

• Time of the day

• Atmospheric humidity

• pH and concentration of reactants

Which of the following is a disadvantage of chemical precipitation?

• 
  High efficiency in removing ions

• Environmentally friendly process

• Production of large amounts of sludge

• Low cost

What role does flocculation play in chemical precipitation?

• 
  Breaking down precipitates into smaller particles

• Agglomerating fine particles into larger, settleable flocs

• Increasing the solubility of compounds

• All correct

Which of the following is an example of a chemical used for co-precipitation of heavy metals?

• 
  Potassium nitrate (KNO3)

• Ferrous sulfate (FeSO4)

• Sodium chloride (NaCl)

• Sodium hydroxide (NaOH)