Kuh Kai Water Aerator

KUH KAI is an innovative product that collides, stirs and breaks down sludge and air into fine particles in a pentagonal cylinder 65cm in length, to accelerate the purification of waste water. Air jetted from a pentagonal cylinder diffuses and radiates outward while eddying in a non-conventional approach.

  • Description
  • Technical specifications


  • Applicable when the water is 1m or deeper
    Applicable to existing or new equipment as long as the water tank or lagoon pond is 1m or deeper.
  • No clogging (Pentagonal tube opening 80mm × 130mm)
    No need to worry about clogging due to the large-diameter opening particularly with intermittent
    processes during denitrification.
  • Power cost reduction (20% to 40%)
    With a small pressure loss between the air in-take and discharge, power costs can be substantially reduced.
  • No sludge flocculation on the tank bottom and the oxygen transfer rate is high due to its “air lift effects”.
    Sludge on the tank bottom is drawn into the pentagonal cylinder and the sludge and air are broken down into
    fine particles which increases the oxygen transfer rate while colliding, being stirred, and rotating. This how the KUH KAI effectively purifies the water.
  • Easy maintenance and management due to its simple structure
    The main body is made of stainless steel and the inside is made of molded resin = Virtually maintenance free. Also, the main body material and the installation method can be changed according to needs.


The World’s First Pentagon-Shaped Diffuser

KUH KAI MIXING DEMONSTRATIONTreatment of Organic Waste using the Activated Sludge Method with microorganisms has become a standard method in wastewater treatment. In recent years, there has been an increase in technology to reduce the footprint of Wastewater Treatment Plants whilst still maintaining and improving the efficiency of the process. One area where there can be an improvement relates to higher efficiency of the Aerator (air diffuser). Some current systems use the bubble type generation utilizing porous materials that can clog through deposits of sludge due to the restrictions on their location and positioning. Often, a large vortex flow utilizing a large amount of energy is required to prevent this occurring. An Aerator was required to prevent the depositing of sludge clogging the Aerator pores without using large amounts of energy. The Kuh Kai Pentagonal Air Lift Aerator was developed to fulfill this need.

KUH KAI FIGURE 1This system, in which the wastewater and solids or gases are mixed, was introduced with a view to efficiently dissolve oxygen into wastewater as well as completely mixing it. A pentagon was developed whereby each pentagon section could be placed on top of one another in multiple stages in a vertical direction (Figure 1) with an opening impingement plate, and having a clearance between the cylindrical portion and the gas ejection nozzle with an Air inlet in a location at the bottom of the tube.

KUH KAI Figure 4If a collision plate shown in Fig 1 was a shape close to a circle, due to the fluid flowing along the circumference,
turbulent flow in the circumferential direction would be less likely to occur. If you have polygonal shape, turbulence is likely to occur due to flow impinges on each side. On the other hand, the flow itself in the circumferential direction does not generate a large enough resistance when you use a square shape such as a triangle, and the flow would be short-circuited and only go upwards. A Pentagon has been determined as the optimum shape as a result. Moreover, from the results of a study of the flow in the vertical direction for the number of stages of the impingement plate, the optimum number of stages was determined to be five stages.


KUH KAI Figure 3In the aeration tank, the primary objective is the provision of adequate oxygen to activate the sludge. Design criteria is usually 2% – 17% depending on the depth, of the oxygen dissolution efficiency. The Kuh Kai aerator, is a deviation from typical design criteria due to its efficiency of oxygen and agitation capabilities as can be seen from these results. In an activated sludge aeration tank, these methods are shown in the figure 4 comparing typical porous aerator versus the Kuh Kai aerator.