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Crossflow microfiltration is a proven technique for removing suspended solids from liquids. Exxflow is a microfiltration process, but unlike rigid membrane systems is unique in that the filter support consists of a patented flexible woven tubular array. The tubes act as a support medium for a secondary, or dynamic membrane that filters out suspended particulate matter down to 0.2 micron. The very solids it is removing form this dynamic membrane. As the membrane builds up so the filtrate quality improves, providing a very fine filtration system.

There are two major advantages Exxflow systems have over conventional crossflow microfilters that allow for better productivity, reliability and flexibility of applications.

The special weave of the cloth promotes the formation of a dynamic membrane which traps fine particulate material while allowing clean water and dissolved substances to pass through. This membrane support system is long lasting, chemically resistant and physically robust. Minor damage to the cloth can be repaired quickly and cheaply, minimising down time and the need with many systems to purchase a new membrane.

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There are various methods of cleaning the cloth once the dynamic membrane has built up to a thickness which inhibits the passage of water through the membrane. During normal operation the feed pump is stopped, depressurising the tubes allowing the membrane to break away from the tube walls. This material is then flushed back into the feed tank where it will eventually be removed as slurry. This process can be enhanced by flushing the tubes with clean water and compressed air, the action of each scours the tubes ready for another dynamic membrane to develop.

After a long time in service the cloth may become blinded with mineral deposits. If these are not removed by normal flushing a dilute acid or alkali solution is very effective at dissolving hard deposits.

Often leaving the cloth to dry completely re-generates its high flux and further action is unnecessary.

Finally if the cloth remains blocked internal cleaning with a high-pressure jet nozzle removes difficult materials, quickly.

This approach to membrane renewal is unique to the flexible Exxflow system and avoids the cleaning and fouling problems that can arise with rigid membranes.

 

The standard linear system is modular in design and can be readily installed or its treatment capacity increased with minimum cost and delay compared with conventional effluent treatment installations.

The system is engineered to be flexible, either part of a turnkey treatment plant or as a final process to ensure discharge consents are met.

The linear system operates at low pressure. Less pump energy is consumed separating the particulate material than in rigid microfiltration membrane systems.

As the membrane support cloth allows extremely fine particulate matter to be captured in the membrane less chemicals are required to flocculate the suspended solids. This saves on both chemical dosing and operating costs.

The linear system can be fully automated, reducing expensive labour costs.

As well as producing a clear final effluent of a quality acceptable for discharge to rivers and drains the linear system saves you money by reducing the burden of expensive liquid disposal costs. After treatment the volume of liquid requiring specialist disposal or subsequent treatment is minimal. So you only pay for the disposal of the waste and not a tanker of water.