Full Description

Fluidized-bed pellet reactor technology was developed to remove water hardness withminimal sludge production. Operation procedures of this process include adding pellets intoa column reactor and directing raw water and chemicals through the bottom of the column,keeping pellets fluidized to prevent them from being coagulated. In this study a processcombining an ultrafiltration (UF) membrane with outside-in flow configuration and a fluidized-bedpellet reactor was proposed for hard water softening. The advantages of such a processinclude a compact reactor footprint, high treatment efficiency, and excellent effluent quality.Three different pellets of various sizes were used: quartz sand, beach sand, and heated ironoxide particles (HIOPs). Results show that with a removal efficiency of less than 16%, a UFmembrane alone is not an effective process for removing hardness due to the slow reactionkinetic of calcium carbonate precipitation without the presence of pellets. When three typesof pellets were added separately, the removal efficiency of the integrated UF/pellet processwas more than 60% at a pH level of 9.0. Hardness removal efficiency improved with increasingpH and pellet surface area, and no significant membrane fouling was observed during theexperiments. Includes 8 references, tables, figures.

Product Details

Edition: Vol. 96 - No. 8 Published: 08/01/2004 Number of Pages: 8File Size: 1 file , 1.6 MB