ChemicalRegeneration of Activated Carbon: Preliminary Studies

Report No WSAA 20

December 1990

 

SYNOPSIS

 

Thisinvestigation was funded by the Urban Water Research Association of Australia.The aim of the study was to investigate possible chemical regenerants forgranular activated carbon used in drinking water treatment.

 

Theeighteen month study was divided into three sections. The areas covered and thekey findings are summarised below:

 

1.            Bench ScaleAdsorption/Regeneration Experiments

 

Batchand column experiments were used to study adsorption of organics onto activatedcarbon and the removal of adsorbed material by the regeneration process.

 

Itwas found that treatment with alkali then acid removed significant amounts ofadsorbed organic material and produced regeneration efficiencies of up to 90%.

 

2.            RegenerationStudies on Carbon from the North Richmond Water Treatment Works

 

Regenerationprocedures were tested on activated carbons that had been used for taste andodour removal at the North Richmond Water Treatment Works over a two yearperiod. Substantial amounts of adsorbed organic material were removed from thesurface by the regeneration procedure. Adsorption experiments showed thecapacity of the regenerated carbon approached that of virgin carbon.

 

3.            ComplementaryInvestigations and Optimisation Experiments

 

These studieswere conducted to determine optimum conditions for adsorbed organics removal interms of desorption time, concentration of alkali and temperature.

 

The resultsindicated that the optimum conditions were:

 

i)                   two hours desorption time

ii)                  1.0M sodium hydroxideconcentration

iii)                temperature of 50C

 

Preliminarywork on the characterisation of the carbon surface and the desorbing organicswas undertaken with the aim of understanding the processes taking place at thesolid/liquid interface during adsorption and during the alkali and acid stepsof the regeneration.

 

 

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