Experimental plant for the physical-chemical treatment of groundwater polluted by Municipal Solid Waste (MSW) leachate, with ammonia recovery

  • Massimo Raboni University of Insubria
  • Vincenzo Torretta University of Insubria - Department of Biotechnologies and Life Sciences
  • Paolo Viotti University of Roma “La Sapienza” - Department of Hydraulics, Transportation and Roads
  • Giordano Urbini University of Insubria - Department of Biotechnologies and Life Sciences
Keywords: ammonia-stripping, landfill leachate, aquifer reclamation

Abstract

The paper documents the results of the experimental treatment of groundwater (flow rate: 300 m3 h-1) polluted by the leachate of an old MSW landfill (7 million tonnes) in northern Italy. The process consists of a coagulation-flocculation pre-treatment at pH > 11, and subsequent ammonia stripping, after heating the water to 35-38 °C by means of the biogas produced by the landfill. The stripped ammonia was recovered by absorption with sulfuric acid, producing a 30% solution of ammonium sulfate, which was reused as a base fertilizer. In addition, the paper reports important operational aspects related to the scaling of the stripping tower’s packing and its effect on pH and temperature profiles inside the towers caused by the closed loop, which recirculates the stripping air coming from the ammonia absorption towers with sulfuric acid. The average removal efficiency of ammonia reached 95.4% with an inlet mean concentration of 199.0 mg L-1.

Published
19/12/2013
Section
Papers