Coagulation-flocculation and ammoniacal stripping of leachates from municipal solid waste landfill

Abstract

The elimination of contamination in leachates from municipal solid waste landfill was studied by sedimentation. The purpose of this study was to evaluate the removal efficiency of turbidity, chemical oxygen demand (COD), suspended solids (SS) and ammonia nitrogen (NH₃). First, by coagulation with aluminium sulphate like inorganic coagulant, and secondly by flocculation with anionic polyacrylamides in quick succession. The use of polyacrylamides after coagulation with Al^{3 +} showed a lower SS removal and slow filtration. Turbidity removal efficacy was over 60% if Al^{3 +} concentration was 190 mg/L. COD elimination by flocculation was 10 to 20% regardless of adding polyacrylamides. Finally, ammoniacal stripping is made in order to reduce the ammoniacal nitrogen concentration in the supernatant liquid obtained after coagulation with Al^{3 +}. The most influential variable in ammoniacal stripping was the agitation time.

Keywords:

• Landfill leachate
• coagulation
• flocculation
• ammoniacal stripping
• polyacrylamides

Acknowledgement

This work was financially supported partly by University College of Technical Engineering of Universidad Politécnica de Madrid.

Notes

∗rpm = Revolutions per minute.