Demonstration testing of alum recovery by liquid ion exchange

Abstract

A 0.63‐L/s sludge flow liquid ion exchange alum recovery plant was tested at the Tampa (Fla.) water filtration plant. Two equipment setups were tested: one providing a rapid mix of sludge and solvent and the other a slow mix. Both were able to recover more than 90 percent of the aluminum and to reduce the dry weight of the sludge as predicted by acidification. Operating costs for a full‐scale system were estimated at about the same as the value of the recovered alum. The economic considerations for installation would be based on treatment costs for the original sludge compared to those for the alum‐free residual.