Where are OxyMem systems currently installed?

OxyMem currently has a broad number of installations (at varying scales) across the globe including; UK, Ireland, Canada, Sweden, Spain, Saudi Arabia, Brazil and Japan.

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How long do the MABR membranes last?

OxyMem will guarantee the membranes for most applications for up to 10 years. The life expectancy is about 20 years.

How can the OxyMem system operate at such low pressures?

The membranes in the OxyMem MABR do not contain any pores and due to the structural integrity of the membranes the lumen does not experience the external hydrostatic pressure. Similar to a swimming snorkel the air in the membrane fibres does not need to overcome hydro-static head as compared to conventional aeration systems. This allows the system to operate as much lower pressures and thus provide significant energy savings.

Which effluents can be treated with OxyMem MABR?

Any that are biologically degradable.

How can I try OxyMem MABR?

OxyMem has a complete range of solutions for you to try MABR.

We have lab scale offerings, mini MABRs for field use, and large-scale packaged systems for onsite demonstration. 

Apply for a Lab Unit


What type of membranes do OxyMem use?

OxyMem manufactures its own membranes.

They are made from dense PDMS (Silicone) and have no pores. The external diameter is 510µm and the internal diameter is 300µm. Oxygen transfers across the membrane wall via diffusion, dependent on a concentration gradient. Oxygen travels from inside the micro bore tubes (where oxygen concentration is greatest), across the wall and into the biofilm (low in oxygen) where is consumed.

Why did you choose to use PDMS membranes?

PDMS membranes are ideal for gas transferring application as they have no pores. They have high gas permeability, are easy to manufacture and are robust.


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Why are there no bubbles in the MABR aeration process?

The MABR does not rely on bubbles to deliver oxygen.

It uses hollow fibre, gas permeable membranes, to support a fixed film ecosystem for the biology which allows for direct delivery of oxygen to the micro-organisms.

Which application is the MABR best suited?

OxyMem MABR will perform well in any environment where these challenges arise:     

- Energy neutrality is a goal    
- Sludge disposal is a challenge / costly    
- Existing treatment system is overloaded    
- Nitrification is a challenge    
- Asset can no longer meet consent    
- Existing asset (tank) needs to be upgraded    
- Footprint is limited


Can the system be retrofitted into an existing plant?

Absolutely, OxyMem solves energy intensive wastewater treatment with an innovative ‘Drop in’ or ‘IFAS style’ deployment for wastewater aeration. OxyMem MABR can compliment existing treatment systems by delivering up to 50% additional biological capacity in an existing aeration basin (without emptying the tank!). It can also be used for replacing a legacy aeration system entirely.

What are the specifications of OxyMem's MABR?

We are now working with our third generation system which is now delivered in the form of a stack-able modular unit with the following specification:

Material                                        Stainless Steel 
Length                                            2.1 m 
Width                                              1.05 m 
Height                                             2.1 m 
Weight (Dry)                                   950 kg
                                          4 m³ 
Membrane Surface Area              2200 m²
Specific Surface Area                   490 m²/m³

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Why are reactors to be installed in series? What is the CAPEX/performance corresponding?

By installing the reactors in series more effective treatment and use of the reactors will be achieved. Also, it allows for better management of the air being supplied (similar to long activates sludge tanks where more air is supplied to the beginning of the tank). There will not be any significant change in CAPEX but there will be an increase in performance.

What is the minimum and maximum flow for which MABR is designed?

There is no technical minimum or maximum, but we are most interested in perusing opportunities greater than 50m3/day.

Do you have a single or two reactors in series?

This depends on the effluent quality required. If it is a standalone OxyMem MABR system we typically design with three reactors in series to achieve N-NH4 concentrations of less than 1mg/l. If the OxyMem system is being deployed as an additional aeration capacity, then it can be added to any aerobic part of the current treatment process.

How many days does it take to build up the biofilm?

This will depend on many variables as with any biological system, Temperature, nature of wastewater, pH but typically 14-60 days.

How much membrane is needed?

This depends on the nature of the wastewater to be treated and what quality the wastewater must be treated to.

The determining quantity is the rate of treatment per m² of membrane surface area. In our Generation 4 Module we deliver 2200m² of surface area. It is important to note that unlike other fixed film applications the OxyMem carrier (membrane) is delivering the oxygen which means the biofilm is 100% active and available for treatment. Another import aspect is the amount of oxygen transferred per m² of surface area, the higher this is the more treatment that can be affected.


What are the OxyMem cleaning and storage procedures?

Biofilm maintenance and control are accomplished automatically by the control system.  Since the membrane is dense and has no pores, no special cleaning is required.  Membranes are not subject to drying; they can be stored indoors, in dry conditions as long as they are protected from sunlight and physical damage.

If the aeration demand increases how will the oxygen transfer be maintained to prevent the system turning anaerobic?

As the load increases the oxygen supplied can be increased by increasing the airflow through the membranes. This results in an increase in overall oxygen concentration within the membranes resulting in increased performance instantaneously. Alternatively in systems where there is a large variation in aeration demand, the Oxygen transfer rate can be increased by increasing the % of oxygen in the air supplied . This will result in more kg of oxygen being transferred for a given membrane surface area.


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How do you control the thickness of the biofilm?

OxyMem systems use a patented biofilm measurement technique, which determines an effective biofilm thickness on the membrane. When the control system determines that the biofilm has grown too thick for the treatment process required, the system takes steps to automatically remove the excess biofilm.  The frequency of cleaning is dependent on the growth rate of the biofilm and the nature of the treatment process, but can vary from once a day to once every two weeks. Self cleaning will typically last 1-2 mins in duration so the energy burden us negligible.

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How do you perform desludging?

Sludge is allowed to settle in the bottom of the tank and removed using a simple removal system. This sludge is very settable with a concentration of up to 10g/l. In a Retrofit installation, the excess biofilm would form part of the MLSS and be removed (i.e. no changes are required to the sludge removal system).

How does the full scale system control the sludge level inside the membrane tanks?

The package plant system has a sludge removal system built into the base of the tank, and we periodically desludge to minimise the build-up of sludge.

At what maximum temperature has the system been tested?

The system has been tested up to 30°C.

We can have the temperature up to 50°-69°C in summer, or for industrial water when the wastewater contains a high concentration of food residues. If the temperature is high, the OTE increases, but the behaviour of bacteria changes. Above 40°C, the bacteria stop working.

How often is biofilm thickness measured?

The frequency of biofilm measurement can be adjusted to site requirements so that as the system operates it only measures the biofilm when it expects a clean to be required. Maximum frequency will be once a day.

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How do you control the amount of flow that is distributed to each process train?

The flow to the unit will be sent to a splitter box which will divide the flow equally between the two process trains.


What is the typical sludge yield in an OxyMem MABR?

The Sludge yield in an OxyMem system is 0.1 - 0.15kgTSS per kgs COD removed.

How long do the MABR membranes last?

OxyMem will guarantee the membranes for most applications for up to 10 years. The life expectancy is about 20 years.

How much Oxygen can be delivered to the wastewater?

OxyMem Generation 4 membranes will deliver on average 12g O2 per m² of surface area when operating on air. For the first time, it now make sense to use higher oxygen concentrations because OxyMem does not waste gas. Using enriched air (>90% oxygen) the same MABR module can deliver four times the oxygen, giving you a lot more treatment capacity for a much lower capital cost.

Does phosphate removal occur?

Some phosphate removal does occur, but this is only the phosphate required for the biofilm growth. 

What is the system's denitrification efficiency?

Currently without trying to achieve denitrification over 50% of the oxidised Ammonia (Nitrate) is removed via denitrification. By limiting oxygen delivery, up to 90% denitrification can be achieved.

Learn more about our simultaneous nitrification and denitrification

Find more information. Read our Case Study.

How does MABR deal with Fats Oils and Greases (FOG)?

FOG in the wastewater will attach to the outside of the biofilm where it will be broken down.

This will require extra Oxygen to break down the FOG and reduce the volume of wastewater that can be treated. Therefore, it is preferable to remove FOG in advance of secondary treatment if possible.

How to improve the diffusion of wastewater with ammonia into the biofilm lower layer close to the membrane?

This has to do with mixing intensity and concentration in the reactor; ammonia diffuses faster into the biofilm as it is a smaller molecule, but this is classic mass transfer.

Learn More about mass transfers:

Conventional Systems Vs MABR

Is there a mixing process inside the tank to improve water diffusion through the solids over the membranes?

Yes. There is a Module integrated mixing system to move water over the surface of the membranes and improve diffusion of nutrients into the biofilm.

How resistant is OxyMem MABR to COD peaks? Is the COD fully treated in that case?

If there is a COD peak in the inlet then it is most likely that the COD in the outlet will rise, but with the OxyMem MABR system constantly monitoring the off-gas from the process a COD peak will result in a change in off-gas, therefore more air can be sent to the OxyMem Module for complete COD oxidation.


How flexible is OxyMem MABR if an acidic influent is injected? Is the biofilm affected or does it resist?

The biofilm in OxyMem MABR is the same as any other biofilm, difficult to get rid of.  Therefore, if there is a shock load of acid in the influent, then it will kill the outer layers of the biofilm, but because the inner layers are protected, once the outer layers slough off the biofilm will regrow again quickly. Additionally, the inner layers will continue working.

How flexible is Oxymem regarding the flow of input (higher/lower volumes) including storm water?

As OxyMem is a biofilm system there is no risk of biomass washout from the reactor. If there is a higher flow rate then the wastewater will have less time in contact with the membranes and the biofilm (reduced HRT) and it may not be treated as effectively as at normal flow. During stormwater events, the wastewater is typically at lower concentrations and therefore the percentage of treatment may not be required. At low flow rates, OxyMem MABR will achieve an improved performance as there is a much higher HRT.

What is the maximum MLSS concentration possible in your design?

We do not typically design with MLSS as we are growing a biofilm on the membranes, therefore a standalone OxyMem MABR system will have a TSS of less than 100mg/l.

In IFAS MABR configuration (OxyFAS) we can operate with MLSS concentrations of over 4000mg/l.

Need more information? Use our resources page to learn more.

Use our resources page to search for the information you need. You will find a wealth of Case Studies, Videos, Articles and Whitepapers to learn about the next generation of aeration.

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