Remediation of Metal Leaching from Newly Regenerated GAC

The aim of the project was to evaluate the benefits of acid treatment prior to the thermal regeneration of the GAC. During thermal regeneration inorganic compounds can undergo molecular changes and this can result in the leaching of compounds into the treated water and also elevated pHs. This often results in the water utility investing time and effort in order to condition the GAC prior to being put back into service.

A custom built acid washing rig and small scale regeneration furnace were employed by WatStech Ltd. to thermally regenerate the GAC samples.

Acid washed regenerated GACs provide several benefits in terms of GAC quality. These included reduced mass losses during thermal regeneration, an improvement in apparent density and an increase in adsorptive capacity (iodine and methylene blue adsorption) following regeneration. Also total and micropore surface area was much improved.