AWWA JAW26053

Spectroscopic and thermal data on sludges from full-scale softening plants showed calcium and magnesium precipitated as calcite and an amorphous hydrated hydroxide, respectively. Magnesium ions were not incorporated into the calcium lattice to form a magnesian calcite. Scanning electron photomicrographs indicated that only the calcium carbonate precipitate has a well-defined crystal structure. The shift of the crystal size distribution (CSD) to greater sizes may be due to bigger calcite crystals rather than to crystal size changes caused by the magnesium hydroxide. The settling rate of the sludges in related to the CSD. Higher fluxes were achieved with an upflow contact clarifier. Includes 46 references, tables, figures.

Product Details

Edition:

Vol. 81 - No. 3

Published:

03/01/1989

Number of Pages:

11

File Size:

1 file , 2.5 MB