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PIK 300

Sulzer Nopon disc diffuser system PIK 300

Membrane disc diffusers for reliable and energy-efficient fine-bubble aeration of tanks in wastewater treatment plants. Suitable for normal continuous aeration systems as well as where intermittent aeration is required, e.g. biological nutrient removal and SBR processes.


  • Self-cleaning EPDM membrane with slits
  • Membrane is fixed by a bayonet type screw-on ring
  • Sliding ring of antifriction material helps in expansion and contraction of the membrane
  • Heavy duty stainless steel ball non-return valve
  • ABS Nopon wedge piece fixing to the pipe means that no glue, solvent or welding is needed in assembly
  • Sliding ring aids in opening the diffuser for maintenance after many years of operation
  • Wedge piece fixing makes it easy to increase, decrease or relocate diffusers when process requirements change
  • Applicable to various pipe materials and dimensions
  • Inlet air temperature is up to 100°C

Working principle

The membrane bulges and slits open during aeration by the pressure of compressed air. The main body distributes the air evenly over the entire surface of the membrane. Air is spread into small bubbles, when released through the membrane. When the air flow is turned off, the pressure of the water above presses the membrane disc tightly to the main body closing the small slits on the membrane. The non-return valve with a stainless steel ball pushed down firmly to an o-ring seal inside makes sure that no water enters the pipeline. During normal operation the non-return valve also works as a control orifice.

  Description Material
1 Main body



2 Wedge piece PP
3 Screw-on ring PP
4 Sliding ring



5 Membrane disc EPDM
6 Flat seal



  Non-return valve  
7 Valve body PP
8 Ball


(stainless steel)

9 O-Ring EPDM


Model range (wedge attachment)

  PIK300VD90 PIK300D90 PIK300SD88,9 PIK3004”
Pipe 90mm PVC 90mmPP 88,9mm SSNS3”PVC NS4”PVC
Main body PSA300 PSA300 PSA300 PSA300-4
Wedge piece PSK90 PSK90 PSK90 PSK4
Slidingring PVR300 PVR300 PVR300 PVR300-3
Screw-on ring PKR300 PKR300 PKR300 PKR300-3
Membrane disc HIK300 HIK300 HIK300 HIK300
Non-return valve PTV15L PTV15L PTV15L PTV15-3
Flatseal PLT15/4 PLT15/4SIL PLT15/5 PLT15/4


Diffuser data

Design air flow range 1,5-8,0 m3/h/diffuser (x(+20°C;1013mbar)
Diffuser level 250 mm (xx
Air temperature, max + 100°C
Max/min assembly depth 3 - 8 m (optimal) (xxx
Diffuser diameter 336 mm
Disc surface area 0,060 m2
Size of bubbles 1 - 3 mm
Diffuser weight 0,795 kg
Max/min interval, c/c 1,25 / 0,4 m

x) When waste water contains chemicals harmful to EPDM or when water temperature is > 30°C or air temperature is close to 80°C, a lower maximum air flow should be used. A peak value of 10 m3/h can be used for max. of 15 min only e.g. for cleaning the membrane. Using air flow less than 1,5 m3/hmust be consulted with Sulzer.

xx) Recommended measure from basin bottom to diffuser top

xxx) Consult Sulzer on depths outside the range