Ultrafiltration
Membranes
UF systems meet growing demand for pure water
With an aging and often overwhelmed water supply infrastructure,
ever more stringent government regulations, and growing
industrial requirements for pure water, municipalities and
companies are increasingly turning to ultrafiltration (UF)
membrane systems for water and wastewater treatment.
- David Lazar
In communities with fast-growing populations and a
commensurate increased demand for drinking water, UF membranes
provide an economical, effective treatment solution for
delivering increased system capacity while protecting consumers
from viruses, bacteria and other harmful pathogens, and ensuring
regulatory compliance.
Water reuse is now mandatory for many municipalities. UF systems
are increasingly being employed by water utilities in wastewater
treatment systems because they allow a significant amount of
wastewater to be reused.
For industrialists, the treatment of raw ground and surface
water using UF can be highly beneficial, and in some cases
essential. UF treatment often results in better operating
reliability and a longer operating lifetime for the downstream
plant and equipment.
Packaged UF Systems
The range of packaged UF membrane systems from
ITT Aquious offers users reliability and robustness across a
wide array of municipal, commercial and industrial applications.
The membranes used in the Aquious UF systems have been approved
for drinking water applications by the majority of the world’s
regulatory agencies, meeting both North American and European
standards.
Pressurized hollow fiber (HF) membranes form the core of the UF
process, providing a physical barrier to contaminants. Product
water quality surpasses that of conventional coagulation,
clarification and filtration processes with the benefit of
simple operation and low lifecycle costs.
Aquious provides UF systems as standard skid-mounted packages to
minimize costs—combining all necessary pumps, instruments,
valves and other standard equipment—and offer complete treatment
solutions. A wide array of options is available to tailor the
standard designs to meet specific customer needs. Aquious also
offers customized systems supported by comprehensive, in-house
design and engineering capabilities.
UF in Plant Pretreatment
In a recent installation, Aquious provided a
UF system for the pretreatment of process water in a
pharmaceutical manufacturing plant in Puerto Rico. Aquious was
asked to deliver a solution to replace an existing RO system
that was experiencing significant fouling issues, making the
system difficult and unreliable to operate. These problems were
burdening the customer with substantial operating and
maintenance costs from membrane replacement and chemicals to
prevent fouling. After analyzing the entire water treatment
system, the engineers proposed a UF pretreatment system followed
by a dual-stage RO system.
Installing the UF system for water pretreatment served to reduce
turbidity and SDI, protecting the RO membranes. The UF system
acts as a barrier to filter suspended and colloidal matter, and
thus provides high quality water so the RO membrane system can
operate efficiently. The UF system contains HF membranes that go
through a series of backflush cycles during the day (up to 200
cycles per day) to remove the impurities that have been
deposited on the UF membranes. The addition of the pretreatment
UF system has greatly reduced RO system fouling. The combined
UF/RO system installed by Aquious has been operating since 2002,
and the RO membranes have not been changed once.
Flexible UF Packages Meet Wide Range of
Demands
A wide range of feed water streams may be used
for the Aquious UF systems including surface water, groundwater,
wastewater and treated drinking water. This makes the systems
suitable for a wide range of applications, including:
• Providing potable water for municipal and private drinking
water supplies;
• Providing industrial process water and irrigation water
for agriculture;
• Recovering filter backwash water;
• Pretreating water prior to
subsequent enhanced
purification processes;
• Treating industrial effluent and domestic sewage; and
• Reusing wastewater.
The Aquious UF systems provide a water output
of consistently high quality. Pathogen and colloid/particle
removal rates are up to 6 log for bacteria and 4 log for
viruses. In the water output, suspended solids are less than1.0
mg/L and turbidity is less than 0.1NTU (based on feed water with
suspended solids less than 200 mg/L).
With day-to-day system operation a significant concern, the
Aquious UF package systems have been designed with automation
and low power consumption, providing users with a low lifecycle
cost solution. The systems can be operated in dead-end or
recirculation modes, allowing recovery rates to be maximized,
thus saving precious raw water resources. Filtration efficiency
is maintained at optimum performance using automated membrane
cleaning—regular backwashing using permeate water and periodic
chemically enhanced backwashing. The systems have also been
designed to require the minimum footprint and headroom.
With a minimum inlet pressure of 20 psi/1.5 Bar (less with a
feed pump) and a maximum inlet pressure of 72.5 psi/5 Bar, the
systems do not require both feed and relift pumps where adequate
water pressure is available. Fully assembled and tested prior to
delivery, the proven operation of these systems is backed by
system and membrane performance warranties.
The Aquious UF packaged systems employ polyethersulfone
membranes to provide the significant advantages of high chlorine
and wide pH tolerance, as well as a high permeability (flux) and
low fouling characteristics. The membranes operate on the
inside-to-out principle and provide a 200kDa molecular weight
cut-off, thus retaining a wide variety of potential
contaminants. The membranes are housed in pressure vessels
(known as modules), which are quick and easy to replace. Their
low cost helps to ensure that the overall life-cycle costs of
the systems are highly competitive. mf
David Lazar, Lazar Creative
Group. For additional information, contact Jorg Menningmann,
general manager of ITT Aquious –Water Equipment Technologies at
561.684.6300, or by e-mail at jorg.mennigmann@itt.com
Source: Membrane Filtration
November 2005 Volume: 1 Number: 1
Copyright © 2005 Scranton Gillette Communications
© 2005 Scranton Gillette Communications, Inc. All rights reserved.
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