Neutralization:

• The excessively acidic or alkaline waste should not be discharged without treatment into a receiving stream, sewer, and effluent treatment plant or on land.

• There are many acceptable methods for neutralization of acidic or alkaline waste water and they are as follows:

• Neutralization of acidic waste:

  • Mixing the waste by the waste from other industry.
  • Passing acidic waste through beds of lime stone.
  • Mixing acidic waste with lime slurry
  • Adding proper proportion of caustic soda or soda ash.
  • Neutralization of alkaline waste:
  • Use of waste boiler flue gas
  • $CO_2$ treatment for alkaline waste
  • Producing $CO_2$ in alkaline waste
  • $H_2SO_4$ treatment

• Acid waste neutralization in industrial process.