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  • The membrane is made of EPDM, uniquely compounded to provide:
    • Long service life.
    • The necessary stiffness and elasticity.
    • Resistance to tear.
    • Resistance to oils.
  • The membrane overlies the polypropylene base plate which is ribbed to ensure high strength.
  • The membrane is fastened to the base plate by means of a rim of stainless steel. This prevents air leakage along the periphery of the membrane.
  • The membrane has numerous small slits through which the air enters the fluid over the membrane in the form of fine bubbles. When air is turned off, the slits close onto the base plate and do not allow leakage of wastewater underneath the membrane.
  • The membrane diffuser DM-320A has a check valve that does not allow wastewater that could have leaked through the slits, to enter the air distribution network. The check valve is shaped as a thickening of the lower central part of the membrane.
  • The membrane diffuser has an outside diameter of 320mm and effective diameter of 285mm.



Air flow per diffuser

1 - 10 m3/h

Diffuser density

0,5 3 diff/m2 (max 5 diff/m2)

Standard oxygen transfer efficiency

14 28 g2/m3.m


21 - 39% at 4,20 m. submergence

Head losses

10-40 cm. water column depending on air flow

Aeration efficiency

3,0 6,7 kg2/ kWh


  • Air distribution network, made of PVC pipe for pressure applications with gasket push-fit joints. These joints allow for pipe expansion and contraction due to temperature fluctuations.
  • Adjustable bottom supports made of plastic and attachment clamps of stainless steel to respectively level and secure the air distribution pipes to the tank floor.
  • Nipple with a seat-shaped lower part. The diffuser is screwed onto the nipple and the nipple is fastened to the air distribution network by means of attachments clamps of stainless steel.
  • System to remove condensation formed in the air distribution network.



Optimum size of the air bubbles
The fine air bubbles have optimum size due to the suitably engineered slit sizes. The air bubbles are not extra fine where the coefficient α (defined as the ratio of oxygen transfer efficiencies in wastewater to clean water under standard conditions) is low, nor are too large where the specific surface area for contact is small. The distance between the diffusers is such that the air bubbles move uniformly towards the water surface and do not coalescent.

High Oxygen Transfer Rate in wastewater
The oxygen transfer rate in wastewater is a function of the transfer rate in clean water and several correction coefficients, the most important of which is the coefficient α. Our practical experience suggests that the diffusers DM-320A operate at a relatively high α coefficient which leads to a high oxygen transfer rate in wastewater. This transfer rate is comparable with the transfer rate of diffusers creating extra fine air bubbles, due to the lower α coefficient of the latter irrespective of their higher oxygen transfer rate in clean water.

Low energy consumption
The aeration efficiency in standard conditions ranges from 3.0 to 6.7 kg 2/ kWh, depending on the technical characteristics of the blower and air flow rate of the diffusers DM-320A.

Long Service Life
The diffusers are corrosion-resistant and have long service life, 10-12 years for the membrane and 20 years for the other components.

Quick and Easy Installation
The installation time is reduced because some of the components are pre-assembled prior to delivery on site.

Lower Capital Investments
The diffusers DM-320A require lower capital investment compared with diffusers with similar technical characteristics.