The Pentair X-Flow Airlift solution applies a clean process and is easy to operate. Airlift Megablock is a modular, energy-efficient and fully automate and has the unique ability to cope with wastewater flow fluctuations by switching off units.



  • Aerobic wastewater treatment
  • Municipal wastewater
  • Low strength industrial wastewater
  • Enchased side stream UF
  • Small footprint
  • Minimal pre-treatment requirements
  • Low TCO

typical use

For efficient wastewater treatment, Pentair has developed the Airlift tehcnology. Airlift consists of a loop with the membranes positioned outside the bioreactor tank, as opposed to submerged concepts with the membranes inside or in a separate part of the bioreactor.

The membrane modules are arranged vertically and aerated continuously. The turbulence created by the air injection enables high flux rates at a very low Trans Membrane Pressure (TMP) and a low energy consumption of 0.25 kWh/m³.

The continuous aeration is the main driving force for the circulation of the activated sludge, while the feed pump is only used to overcome the hydraulic losses. 

Periodic backflushing and/or relaxation intervals are used to control the cake layer formation inside the membrane tubes and to extend the intervals between maintenance cleanings. The continuous aeration also controls fouling inside individual membrane tubes. 

The 3 m long 8” modules allow a bioreactor to run up to 15 g/l MLSS biomass with a limited space requirement, while offering a clean and safe environment.


The Airlift Megablock is typically used for treating municipal or industrial wastewater. Through the combination of biomass and membranes, the permeate is suitable for reuse of irrigation. 

Due to its 3 mm X-Flow PES membranes, the tightest in the industry, the Megablock can be considered true ultrafiltration (0,025 micron). The 3 meter long membranes are mounted in a modular unit which, due to its smart design, enables easy accessibility for cleaning and maintenance. Most importantly, the system significantly shortens the construction period. The Megablock is typically a flat slab construction based on sets of 36 modules. 

The Airlift principle is a fully automated process in which sludge and air recirculate at the lowest possible energy consumption. The filtered water is separated by the membranes, which are kept clean by automated process steps, including backwashes and drain sequences. 
Its optimized design and fully automated process limit recirculation and minimize the auxilary equipment (valves, pumps, instruments and control equipment).

With its high flux rates and output, its low energy consumption and economical design, Megablock is superior in almost all respects to any conventional or submerged MBR technologies suitable for 7000m3 per day and more.


Airlift uniquely combines membranes with biological treatment. With carefully selected partners for the biological part, Pentair develops innovative and ready-to-use membrane installations that meet both regulatory and financial KPI’s. The Pentair scope consists of the modular skid concept, X-Flow tubular membranes, engineering, commissioning and process optimization. 

As one of the world’s foremost membrane technology knowledge centers, we share our scientific know-how and practical experience with our partners to make the difference in challenging filtration projects. Our unique Membrane+ approach during start-up and commissioning ensure a flawlessly functioning MBR that will beat the expectations.

Fields of application

The need for reusing wastewater, both industrial and municipal, requires top quality membranes which provide directly reuseable water. The ultrafiltration membranes applied can be compared to those used in drinking water plants. Energy consumption is at the level of submerged membrane systems or lower, due to the efficient use of process conditions for flux enhancement. 

Another major advantage of the Airlift technology is that the membrane modules are placed outside the bioreactor in a clean and dry setup. The wastewater itself is inside the membranes rather than outside, thus eliminating the problem of maintaining modules submerged in activated sludge. The membranes are easily accessible and cleaned.

For capacities >7,5 MLD the application of our Airlift Megablock can be of interest.

Applications for the Megablock are large-scale municipal and industrial wastewater treatment. By combining biomass and membrane elements, the wastewater can be reused, for example for irrigation purposes. The combination of biological treatment with UF membrane separation provides a reliable single barrier for bacteria and viruses and enables wastewater treatment plants to efficiently handle fluctuating amounts of water while complying with stringent regulatory requirements. Example applications of the Megablock are municipal wastewater treatment, hospital wastewater and refinery wastewater.

The sweet spot for the Megablock is above 7,5 MLD, whereas the regular Airlift technology is suitable for smaller projects.

Featured cases

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Ootmarsum, The Netherlands

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Johor Bahru, Malaysia

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