Nalco Chemical Company

E H Zeiher

Cynthia A Soderquist

William F McCoy

Claudia C Pierce

Kenneth P Fivizzani

Brian F Post

Timothy L Chaffin

An in-line apparatus for monitoring membrane deposition is provided having an exterior body that defines an interior compartment for receiving a fluid stream. A coupon rack is positioned in the interior compartment and suspends at least one coupon holder. The coupon holder holds at least one membrane for collection of deposition present within a filtration system. The apparatus allows examination of membrane surface deposition without sacrificing a membrane element and also provides timely diagnostic information on a filtration system. The present invention also provides a method of monitoring membrane deposition as well as a filtration system incorporating an in-line apparatus for monitoring membrane deposition.

Apparatus and method for the monitoring of membrane deposition

A method for inhibiting calcium sulfate scale formation and deposition and/or dispersing iron from a feedstream passing through a reverse osmosis system which comprises the steps of: controlling the pH of the feedstream within the range between about 6.0 to about 7.0; controlling the temperature of the feedstream within the range between about 50.degree. to about 80.degree. F.; and adding a scale inhibitor and/or iron dispersant to the feedstream in an amount between about 0.002 ppm per ppm hardness (as CaCO.sub.3) of the feedstream to about 0.005 ppm per ppm hardness (as CaCO.sub.3) of the feedstream, the scale inhibitor comprising a water-soluble organic phosphonate, an N-substituted acrylamide polymer, caustic and water.

Method for inhibiting scale formation and/or dispersing iron in reverse

A method for inhibiting calcium sulfate scale formation and deposition and/or dispersing iron from a feedstream passing through a reverse osmosis system which comprises the steps of: controlling the pH of the feedstream within the range between about 6.0 to about 7.0; controlling the temperature of the feedstream within the range between about 50.degree. to about 80.degree. F.; and adding a scale inhibitor and/or iron disperant to the feedstream in an amount between about 0.002 ppm per ppm hardness (as CaCO.sub.3) of the feedstream to about 0.005 ppm per ppm hardness (as CaCO.sub.3) of the feedstream, the scale inhibitor comprising a water-soluble organic phosphonate and an N-substituted acrylamide polymer containing an amide structure as follows: ##STR1## where R.sub.2 is hydrogen or methyl, R.sub.1 is a hydrogen or an alkyl, and R is alkylene or phenylene and X is sulfonate, (poly) hydroxyl, (poly) carboxyl or carbonyl, and combinations thereof, with the weight ratio of polymer to phosphonate being within the range of about 0.2:1 to about 2:1; provided that when X is sulfonated then R--X-- is selected from the group consisting of sulfomethyl and 2-sulfoethyl.

Growing community of inventors

Naperville, IL, United States of America

E H Zeiher