Ultrafiltration

ADVANCED WATER

TREATMENTTECHNIQUE

BY

K.P.VINEETH

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SOME OF WATER TREATMENT PROCESS ADSORPTION. REVERSE OSMOSIS. ION EXCHANGE. ULTRA FILTRATION. DEFLUORIDATION. REMOVAL OF IRON AND

MANGANESE. REMOVAL OF COLOUR AND

ODOUR.

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ULTRA FILTRATION Ultra filtration is a

separation process using membranes with pore sizes in the range of 0.1 to 0.001 micron.

Typically, ultra filtration will remove high molecular-weight substances, colloidal materials, and organic and inorganic polymeric molecules

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ULTRA FILTRATION OPERATION SCHEME Influent water enters the tubes and is

filtered against the wall surface; Silt, sediment, turbidity as well as microorganisms are retained inside the membrane wall as they cannot pass the fine tube walls.

Filtered water (permeate) is collected on the exterior wall of the fibers and exits the permeate port.

During flushing cycle, the solenoid valve on drain port opens, forcing water through the membrane fibers and removing all accumulated debris down the drain line. The cycle can be adjusted depending on water quality.

Forward and Backward flushing are achieved automatically and Manually.

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Normal Operation Valve (A Open , B Closed )

Backward Flush Forward Valve ( A closed, B Closed)

Forward FlushValve ( A opened , B opened )

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ULTRA FILTRATION MEMBRANES

Ultra filtration Membrane

modules come in plate-and-frame, capillary, spiral-wound, and tubular configurations. All configurations have been used successfully in different process applications.

Each configuration is specially suited for some specific applications and there are many applications where more than one configuration is appropriate.

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FACTORS AFFECTING THE PERFORMANCE OF ULTRA FILTRATION Flow Across the Membrane

Surface.

Operating Pressure.

Operating Temperature.

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TECHNICAL SPECIFICATION OF THEULTRA FILTRATION MEMBRANE: Pore size of membrane :

0.001micron Type of membrane : Multi bore /

Seven Pore Number of bores per fiber : 7 Material of membrane : Polyether

sulfone Diameter bores : 0.9 mm Diameter fiber : 4.2mm Maximum system pressure : 10 bar pH range during operation : 3 – 10 Maximum water

temperature:40°C& 80°C(Special housing)

pH range during cleaning : 1 – 13

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PERFORMANCE OF ULTRA FILTRATION SYSTEMS In high purity water systems, ultra

filtration is slowly replacing the traditional 0.2-micron cartridge filters. In Japan, practically all of the semiconductor industry follows this practice.

An ultra filtration has a nominal pore size of 0.003micron.

When an ultra filtration membrane is used instead of a 0.2-micron cartridge filter, particle removal efficiency is greatly improved.

In addition, Ultra filtration membranes are not susceptible to the problem of bacteria growing through them, as is the case with 0.2-micron filters.

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OPERATION AND MAINTENANCE Ultra filtration system

operation and maintenance is similar to that of reverse osmosis systems.

Daily records of feed and permeate flow, feed pressure and temperature, and pressure drop across the system should be kept.

Membranes should be cleaned when the system permeate rate drops by 10% or more.

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CONCLUSIONS Ultra filtration will find an

increasing application in the production of high purity water.

The basic principles

outlined here should help in the understanding and use of this technology

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REFERENCE Gaudet, P.W. "Point-of-use

Ultra filtration of De-ionized Water and Effects of Microelectronics Device Quality, American Society for Testing and Materials", 1984.

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GLOSSARY OF TERMS Feed - Liquid to be treated by

the ultra filtration system. Permeate - Liquid stream that

passes through the membrane.

Flux - Permeate flow per unit area of membrane per unit time (gallons/ft²/day)

Flow Velocity - Rate at which the liquid goes along the membrane surface, expressed in length per unit time (ft/sec)

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