AWWA ACE94186

There are several reasons for a utility to consider converting an existing sand filter to a granular activated carbon (GAC) filter: GAC has been shown to be an effective filter medium; GAC provides water quality protection via chemical contaminant adsorption; GAC offers potential cost savings over powdered activated carbon (PAC) for systems using PAC year around because of more efficient use of adsorptive capacity, reduction of chemical requirements and reduction in sludge volumes generated; GAC provides continuous taste and odor control that is not realized with other episodic-type control techniques; and In anticipation of the Information Collection Rule and the pilot tests that will be required, replacement of one of several filters with GAC would provide real time, real condition data to satisfy the utility's obligation. In addition to the potential benefits, there are other practical considerations to take into account when deciding to convert to a GAC filter. These factors include the flow requirements, pressure drop restrictions, filter run time desired, backwash requirements, and physical properties of the GAC. The cost for converting to GAC filtration has been incorrectly considered to be expensive. Although a filter conversion sometimes appears to be a relatively large outlay of capital at one point in time, the actual cost to the consumer, when average over the life span of the GAC, is actually rather minimal.

Product Details

Published:

01/01/1994

ISBN(s):

0898677750

Number of Pages:

14

File Size:

1 file , 330 KB