AWWA ACE99581

Reverse osmosis (RO) and nanofiltration (NF) membrane processes are diffusion-controlled processes, and are considered to be water treatment processes that can produce corrosive permeate waters as RO and the newer NF membranes remove too much calcium and alkalinity to provide a buffered or easily stabilized finished water. Consequently, post-treatment of the membrane permeate water from these types of membrane processes is required prior to distribution in a drinking water system. Microfiltration and ultrafiltration processes do not produce corrosive filtrate water because they do not remove any dissolved calcium or alkalinity, and as a result do not directly effect the finished water buffering or stabilization, and will not be discussed in this paper. Permeate post-treatment for RO membrane processes in general can be fairly extensive and depends to a large extent upon the type and quality of the raw water supply. The amount of post-treatment required for NF is less than RO to achieve stabilization. Regardless, it has been shown that a properly treated permeate water produces a low corrosion potential water. An integrated RO and NF membrane process with proper pre- and post-treatment can achieve simultaneous compliance with the Lead and Copper Rule, the Disinfectant/Disinfection Byproducts (DBP) Rule, and maximum contaminant levels associated with many pesticides, heavy metals, and microorganisms.

Product Details

Published:

01/01/1999

ISBN(s):

1583210016

Number of Pages:

7

File Size:

1 file , 160 KB