AWWA JAW17368

This article examines the removal of fulvic acid by lime softening, mechanisms of removal, and the factors influencing removal. Lime softening was found to remove a significant fraction of the fulvic acid extracted from groundwater in jar tests. Removal of the fulvic acid was attributed to coprecipitation and involved the adsorption of fulvic acid onto calcium carbonate crystals in the early stages of the softening reaction, retarding their growth and distorting their shape. Favorable conditions for removal included high pH, a high calcium concentration, and a low carbonate concentration. Jar tests indicated that the softening process can be modified to improve the removal of fulvic acid without compromising the removal of hardness. The removability of each different fraction of groundwater humic material was associated with its adsorbability into calcium carbonate and its ability to bind calcium. The potential application of the jar test results to full-scale softening plants is briefly addressed. Includes 57 references, tables, figures.

Product Details

Edition:

Vol. 77 - No. 8

Published:

08/01/1985

Number of Pages:

11

File Size:

1 file , 3.4 MB