AWWA JAW60491

Minimizing aluminum residuals in plants usingalum-based coagulants can help to minimize thepotential of aluminum postprecipitation in thedistribution system. Reducing precipitation potentialcan help to minimize the financial and public healthrisks associated with the formation of precipitates inwater transmission and distribution systems. Thisarticle examines the ability of orthophosphate, whichis known to interact with aluminum at concentrationscommonly found in drinking water, to reducesoluble aluminum levels through the coagulation/flocculation/separation process. An alternative usefor orthophosphate as an aluminum control methodis proposed. In bench-scale tests, orthophosphateaddition during rapid mix showed the consistentability to reduce residual aluminum concentrationwhen using alum as a coagulant. Adding orthophosphatein bench-scale tests reduced residual dissolvedaluminum concentrations by as much as 350 µg/L.The effect of orthophosphate addition varied withdose, pH, temperature, and chemical additionsequence. Includes 25 references, tables, figures.

Product Details

Edition:

Vol. 96 - No. 9

Published:

09/01/2004

Number of Pages:

11

File Size:

1 file , 150 KB