Abstract: An adaptive control method for producing high purity water, the method having the ability to produce high purity water on a continuous basis having a resistivity in the range of 0.8 to 4 megohm-cm. The method comprises the steps of providing a feedwater to be purified and providing a first reverse osmosis unit having a first high pressure side and a first low pressure side and having a first permeate produced at the first low pressure side. The pH of the feedwater to be introduced to the high pressure of the first reverse osmosis unit is monitored before introducing the feedwater to the high pressure side of the first reverse osmosis unit. Also, the feedwater is maintained in a temperature range of 45.degree. to 80.degree. F. A second reverse osmosis unit is provided having a second high pressure side and a second low pressure side for producing high purity product water.

Abstract: A method of purifying impure water to provide drinking water using an apparatus, the method comprising the steps of providing a microfiltration unit, a reverse osmosis unit and a CIP (clean-in-place) tank containing retentate interconnected to permit backflushing the microfiltration filter with retentate and continued or uninterrupted operation of the reverse osmosis unit by directing retentate thereto.

Abstract: A method for producing high purity product water using a three pass reverse osmosis system.

Abstract: A method for producing high purity product water using a three pass reverse osmosis system.

Abstract: A method and cleaning system is disclosed for cleaning the outer surface of a fouled microfiltration (MF) or ultrafiltration (UF) semipermeable hollow fiber membrane after its initial stable transmembrane flux has been decreased to an unacceptably low level. The method is specifically applicable to any fiber used to withdraw purified water from dirty water, particularly water containing organic matter including beneficial bacteria and/or undesirable inorganic salts, where the viability of the bacteria population is to be maintained. The membrane is cleaned by flowing a cleaning fluid, preferably a biocidal oxidative electrolyte having an oxidizing anion and an associated cation through the clean, permeate-side of the membrane, at low pressure no more than the bubble pressure breakthrough, usually <300 kPa (30 psig) for a MF or UF fiber.

Abstract: A frameless array unconfined in a modular shell, proves to be a surprisingly effective membrane device for withdrawing permeate from a substrate, the flux through the membranes reaching an essentially constant relatively high value because of the critical deployment of fibers of the array as a skein, arching in a buoyantly swayable generally parabolic configuration within the substrate, above at least one of the array's headers in which the terminal end portions of the fibers are potted. The length of each fiber must be greater than the direct center-to-center distance between the array's pair of headers. For use in a large reservoir, an assembly of the array and a gas distributor means has fibers preferably >0.5 meter long, which together provide a surface area >10 m.sup.2. The terminal end portions of fibers in each header are substantially free from fiber-to-fiber contact.