Waste water treatment solutions in sewage sector

Aeration equipment


This system is used to carry out a biological treatment called the active sludge method in the water treatment process. It is equipment to feed air necessary to cause absorption of contaminants in the sewage by active sludge.

The aeration equipment supplied by METAWATER uses a ceramic diffuser highly acclaimed for its excellent performance and stability.

Aeration equipment


Besides the swirl flow type (most frequently adopted type in Japan), we will design and install the optimal aeration system to address diverse needs of customers including the energy saving total area aeration type and space saving deep tank aeration type.


Ceramic diffuser

A ceramic diffuser is available in two types: air diffusion plate and diffusion cylinder. Since 1934, our ceramic diffusers have been delivered to many treatment plants and demonstrated excellent results. All of these diffusers are micro-bubble diffusers of porous ceramics produced by baking ceramic particles and binders at high temperature. A series of air diffusion plates or the diffusion cylinders are integrated in a corrosion resistant holder with a mechanism to generate uniform bubbles. These diffusion components can be replaced easily. These holders are mounted on riser pipes as an air diffusion system.

■Characteristics of ceramic diffuser

  • The super-fine bubbles generated from uniform pores can maintain a high oxygen transfer efficiency for long hours in a stable manner.
  • Because of ceramic material, it has an excellent corrosion resistance.
  • Several types of holders are available so that the optimum type can be selected for each treatment method.
  • Because it has a mechanism to generate uniform bubbles, a series of problems associated with a difference of individual diffusers in terms of aeration resistance, level of installation or pipe resistance are unlikely to occur.
Item Size
Dry aeration level
Nominal pore diameter
Standard aeration level
Air diffusion plate
300 × 300
260 3.9 80~100L
Air diffusion plate
(Total area aeration type)

100 × 300
× 30
260 3.9 20~40L
Diffusion cylinder
Ø75 × Ø50
× 500
1200L/min 260 3.4 120~150L
1900L/min 450

Holder with uniform bubble generation mechanism

The ceramic diffusers are integrated in a holder with a uniform bubble generation mechanism. To enable uniform bubble generation and to achieve high oxygen transfer efficiency, the holder has an orifice for each diffuser.

  • SUS air diffusion plate holder
  • Diffusion cylinder holder assembly
  • SUS air diffusion plate holder of total area type

Swirl-type aeration system

In this approach, an aeration system is installed on one side of an aeration tank. By injecting air from the aeration system to create a swirl flow inside the tank, wastewater and active sludge are mixed and agitated. Through this process, the oxygen contained in the feed air is dissolved efficiently. This aeration approach is most frequently used in wastewater treatment plants where the active sludge method is adopted.

  • Swirl-type aeration system
  • Swirl-type aeration system

On a riser pipe, multiple air diffusion plates and diffusion cylinders are mounted.

Total area aeration system

Total area aeration system has been developed to address the social requirement for energy saving in wastewater treatment. Our product was accredited as an "energy saving aeration system" in the technology assessment by the Ministry of Construction in 1982. For energy saving in the wastewater treatment, the effect obtained by reducing the power spent on blower is significant. Therefore, an increasing number of total area aeration-type systems have been adopted in recent years in construction and addition of new treatment plants or modification of existing aeration systems.

■Characteristics of system

Composition of total area aeration system

Composition of total area aeration system
  • Installation status

    Installation status
  • Aeration status

    Aeration status

Deep tank aeration system

In recent years, it has become extremely difficult to acquire a construction site for a wastewater treatment plant. Needs for a deep aeration tank are increasing from the standpoint of efficient area usage. In 1973, we delivered the first deep tank aeration system in Japan. Thereafter, we have continued to optimize the design through accumulation of operation data and the data obtained from internal experiment tanks equivalent to the actual scale. We have delivered our products to treatment facilities all over Japan.

■Characteristics of system

Deep tank aeration system

Deep aeration tanks have the following characteristics compared to the standard tanks:

  • Reduced area for construction.
  • Aeration depth can be set to the same level as in the standard tank. In this case:
    1. It is possible to use the same blower as those for standard tanks.
    2. The equivalent quality of treated water is obtained.
    3. Oxygen transfer level per unit power is higher.
    4. Mixing characteristics are equivalent by installing baffle plate and so forth.
  • By increasing the aeration depth, oxygen transfer efficiency can be enhanced.
  • By using the ceramic air diffusion plate and diffusion cylinder for the diffuser of deep aeration tank, high treatment efficiency is achieved in a stable manner.

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