Integrated Membrane Water Treatment System: Structure, Uses & Benefits

Integrated modular systems combine various water treatment components into a single complete system.

An integrated membrane system is not designed by adding filtration, separation, pumping, and control equipment as separate units. Instead, it is designed to fit the incoming water, the required treatment quality, and the site conditions.

This process can be good for projects requiring wastewater treatment, desalination, and/or water reuse, where space is limited. But, for each project, there is not a single arrangement of membranes.

The correct membrane technology is determined by the feed water, the treatment demands, and the outlet water quality.

What Is an Integrated Membrane Water Treatment System?

An integrated membrane system is a system of membrane equipment that includes components to run the treatment processes.

The treatment train can consist of ultrafiltration (UF), membrane bioreactor (MBR), nanofiltration (NF), reverse osmosis (RO), or a combination of the different technologies.

The equipment may be designed as a skid-mounted or other prefabricated system. Major components may be pre-assembled in the factory, reducing transportation, installation, and site coordination.

Membrane-based configurations with UF, MBR, NF, and RO are available in QILEE's Integrated Modular Systems for various municipal and industrial treatment needs.

How Is an Integrated Membrane System Structured?

The sequence of process steps depends on the water source and the desired treatment, but most water systems feature several basic functions.

Pretreatment

Solids or oils, scaling substances, or other conditions present upstream that may impact the membrane performance can be controlled through screening, filtering, chemicals, or other pretreatment processes.

Membrane separation

The selected membrane carries out the primary separation process. Suspended solids, coliforms, and microorganisms can be removed by UF. MBR is a biological wastewater treatment system that uses membrane separation. NF selectively removes some dissolved salts and can support water softening, while RO removes a much broader range of dissolved salts.

Pumps and controls

Pumps are used to provide flow and pressure, and valves, sensors, control panels, and instruments are used to control the process.

Cleaning and protection:

Maintenance operations such as backwashing, air scouring, chemical cleaning, or other functions may be necessary to control fouling and ensure performance depending on the membrane technology.

Which Membrane Technology Should Be Used?

The treatment problem must be considered first and not the equipment name in the selection of membranes. There are different roles for each technology.

UF can be used upstream of RO to enhance feed-water quality, and MBR can include biological treatment and membrane separation in a wastewater process.

The correct arrangement will be determined by the quality of feed water, flow rate, desired water quality, fouling potential, operating conditions, and use.

Where Are Integrated Membrane Systems Used?

Integrated membrane systems can be used for various water and wastewater uses.

Municipal water and wastewater: Membrane treatment can be used to treat and reuse sewage, purify water, and more. MBR application is especially important where the biological treatment and separation by membranes are required in a single treatment system.

Process wastewater: Industrial plants may need to treat process water, challenging waste streams or water for reuse. The membrane combination will be determined by the contaminants and the quality of the discharge or reuse desired.

Desalination: RO is employed when the removal of salts requires dissolved salts to be removed. Pretreatment like UF can be added prior to RO, depending on the feed-water conditions.

Water reuse: If wastewater must be treated to a specific water reuse requirement, an integrated treatment train can be used that includes biological treatment, filtration and dissolved solids removal.

Space limited projects: Prefabricated and containerized systems may be beneficial in areas where a fixed treatment plant is impractical. QILEE offers 20-ft and 40-ft containerized treatment solutions for water reuse, desalination, and industrial wastewater treatment.

What Are the Main Benefits?

Faster Site Installation

Much of the equipment assembly and integration can be done prior to delivery, through the technique of prefabrication. This can save mechanical and electrical work at the site of the project and make the installation easier.

More Efficient Use of Space

The combination of treatment functions in a coordinated module may help minimize the space requirement for equipment. This is useful for upgrading plants, remote plants, and for limited spaces.

Easier Capacity Expansion

Depending on the original design, additional modules or capacity can be considered as demand grows.

Available space, utilities, pumping capacity and controls are factored into what can be added later and should be considered at an early stage in future expansion.

More Consistent Assembly

Piping, electrical equipment, instruments, pumps, and membrane equipment can be fabricated in a controlled environment in the factory. Testing and inspection prior to shipment can help to uncover issues during integration before installation.

What Should Buyers Check Before Selecting a System?

The selection of an integrated membrane system is not sufficient using only capacity. It is important for buyers to establish treatment needs prior to requesting a particular configuration.

Important information includes:

• The source information for feedwater and water-quality data from the laboratory.
• Average and peak flow rate
• Required treated-water quality
• The intended use after reuse, discharge, or process application.
• Pretreatment requirements
• Appropriate membrane technology
• Operating conditions
• Cleaning and maintenance requirements.
• The footprint and utility connections available.
• Installation conditions
• Future expansion requirements

This information helps determine whether one membrane stage is enough or whether a combination of several technologies is needed. For industrial uses, water-quality testing is particularly important because treatment methods may differ from facility to facility, depending on the wastewater characteristics and flow rate.

When Does an Integrated Approach Make Sense?

A combined membrane approach is useful when multiple treatment needs are to be met in a coordinated and integrated way.

In one instance, a wastewater reuse project might include biological treatment before membrane filtration and another dissolved-solids removal system. Pretreatment may be required prior to RO for a desalination project. In both cases, integration is not concerned with each treatment stage or supporting equipment as a stand-alone system but rather coordinates the full treatment process and equipment.

The system plan should be based on the full treatment goal, taking into account water quality goals, capacity, site constraints, maintenance considerations, and future needs.

Conclusion

An integrated membrane water treatment system is a coordinated unit comprising membrane treatment, pumps, controls, pretreatment, piping, and maintenance.

There is no universal membrane arrangement, as UF, MBR, NF, and RO perform different treatment functions. The correct configuration is dependent upon the feed water, flow rate, desired water quality, site characteristics, and use of the water.

The first step for a potential buyer is to identify the treatment requirements. Knowing the water source, contaminants, flow rate, water quality target, available space, and future capacity requirements will help to decide what type of membrane stages to include in the system.