REVERSE OSMOSIS PROVIDES REUSABLE WATER FROM
ELECTRONICS WASTE
Matthew D. Beasley, Applications Engineer
Lionel Luttinger, Senior Research Chemist
Permutit Research Center
Princeton, New Jersey 08540
Cesare Caprio, Engineer
IBM Corporation
Manassas, Virginia 22110
INTRODUCTION
At the IBM facility in Manassas, Virginia, reverse osmosis (RO) is used as a means of
demineralizing the raw water supply prior to being fed to the mixed-bed demineralizers.
The deionized water system is used for direct support of the semiconductor development.
The quality of rinse water needed for such an industry exceeds 16-megohm resistivity.
The raw water supplied to IBM is from a municipal surface water reservoir system.   Its
treatment processes include chemical precipitation, sand filtration and chlorination.   The
quality of this water ranges between 95-170 mg/1 as total dissolved solids (TDS).   The pre-
treatment processes in use at IBM prior to the RO units are shown in Figure 1.   Acidification with sulphuric acid, to maintain a negative Langlier Index, is the first step, followed
H2S04
T^A
Cat ionic Polymer
T^^A
Sfi Polishing Filters        I       J[
Media AG Filters
§>
WWW
Carbon Purifiers
RO Permeator System
Macropak 6
Macropak 7
)
Macropak 8
ZHZ
Figure 1.   Reverse osmosis system.
To Dl Water System
RO Permeator System
Reject Staging      4:2 Configuration Winter Operation
3:2 Configuration Summer Operation
by in-line coagulation with a cationic polymer on a sand filter bed, to reduce the fouling
index of the water to less than 3.0.   The third pretreatment step is carbon adsorption,
where organics as well as chlorine are removed.   Chlorine must be removed because of its
ability to damage the polyamide membranes in the du Pont RO modules.   Before the water
is fed to the RO units, final polishing filtration is performed with 5-ji cartridge filters. The
RO system has been operational since 1972, with problems occurring only when the raw
water supply was changed from a well water to a surface water source.
Segregated drainage piping as shown in Figure 2 was provided within the two manufacturing buildings to facilitate the segregated treatment processes at the industrial waste
630