Wastewater treatment of recycling cardboard plants

Abstract

A study is made of the coagulation‐flocculation process for wastewater from paper industries which recycle cardboard with various coagulants: FeCl₃.6H₂O, Al₂(SO₄)₃.18H₂O and various commercial cationic and anionic polyelectrolytes. For each coagulant the concentration, agitation speed and agitation time have been optimized, carrying out the tests at the pH and temperature at the time of discharge.

As control parameters, turbidity, chemical oxygen demand COD, total solids TS and volatile solids VS, have been used.

The polynomic equation relating the percentage of clarification to each of the variables studied for each coagulant is established.

Key words:

• cardboard
• wastewater treatment
• coagulation‐flocculation
• COD
• polyelectrolytes