How should the effluent be treated before discharge?

An effluent before it is to be discharged has to be treated to kill its hazardous effects. If an effluent is acideic , than it has to be neutralized using some base like hydroxides to make it neutral and if its too basic then Sulphuric acid is added to make it neutral. ALso floculants and co-agulants are also used to remove the impurities and solid wastes present in the liquid.After that many pH test,conductivity tests and its concentration is examined before it is discharged. All this is carried out in ETP plant.