Aeration equipment
Outline
This system is used to carry out a biological treatment called the active sludge method during the water treatment process. It is equipment which facilitates the feeding of air that is necessary to cause the absorption of contaminants in the sewage by active sludge.
The aeration equipment supplied by METAWATER uses a ceramic diffuser that is highly acclaimed for its excellent performance and stability.
Features
Besides the swirl flow type, the most widely adopted in Japan, we design and install optimal aeration systems to address the diverse needs of customers, including the energy-saving total area aeration type and space-saving deep tank aeration type.
Product series
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 have demonstrated excellent results. All of these diffusers are micro-bubble diffusers. They are made with porous ceramics produced by baking ceramic particles and binders at high temperatures. Both air diffusion plates and diffusion cylinders are mounted in a corrosion resistant holder in an easily replaceable way. There is also a mechanism in place which serves to generate uniform bubbles. They are installed on riser pipes as an air diffusion system.
Features of ceramic diffuser
- The micro bubbles generated by uniform pores can maintain a high level of oxygen transfer efficiency for many hours in a stable manner.
- The ceramic material means excellent corrosion resistance.
- Several types of holders are available which are suited for each of the treatment methods.
- It has a mechanism which serves to generate uniform bubbles, so a series of problems associated with differences between individual diffusers in terms of aeration resistance, level of installation, or pipe resistance, are unlikely to occur.
| Item | External dimensions (mm) | Dry aeration level (20°C, 0.49 kPa) | Nominal pore diameter (μm) | Stiffness (MPa) | Standard aeration level (20°C, atmospheric pressure) | Weight (kg) |
|---|---|---|---|---|---|---|
| Air diffusion plate |
 300 x 300 x 30 |
1200 mL/cm2･min | 260 | 3.9 | 80-100 L/min/piece | 4 |
| 1800 mL/cm2･min | 300 | |||||
| 3000 mL/cm2･min | 400 | |||||
| Air diffusion plate (total area aeration type) |
 100 x 300 x 30 |
1200 mL/cm2･min | 260 | 3.9 | 20-40 L/min/piece | 1.3 |
| Diffusion cylinder |
 Ø75 x Ø50 x 500 |
1200L/min | 260 | 3.4 | 120-150 L/min/piece | 2 |
| 1900L/min | 450 |
Holder with uniform bubble generation mechanism
The ceramic diffusers are mounted on a holder that is equipped with a uniform bubble generation mechanism. To enable uniform bubble generation and to achieve a high level of oxygen transfer efficiency, the holder has an orifice for each diffuser.
- Air diffusion plate holder made of stainless steel
- Diffusion cylinder holder assembly
- Air diffusion plate holder of a total area type made of stainless steel
Swirl-type aeration system
In this type, an aeration device, installed on one side of an aeration tank, injects air to create a swirl flow inside the tank, mixing and agitating wastewater and active sludge and, at the same time, efficiently dissolving the oxygen within the supplied air. This type is most frequently used in wastewater treatment plants that deploy the active sludge method.
Total area aeration system
The total area aeration system was developed to address the social requirement for energy saving in wastewater treatment and was accredited in 1982 by the Ministry of Construction as an “energy saving aeration system” during a technology assessment. Since the effect in terms of reducing the power consumption of the blower is significant when it comes to energy saving during wastewater treatment, an increasing number of total area aeration-type systems have been adopted in recent years for the construction and addition of new treatment plants or for the modification of existing aeration systems.
Features of the system
Deep tank aeration system
In recent years, it has become extremely difficult to acquire construction sites for wastewater treatment plants. As such, the demand for deep aeration tanks is increasing so that efficient use can be made of the land area available. Since the delivery of the first deep tank aeration system in Japan in 1973, we have accumulated a variety of data through the practical operation and from internal experimental tanks of actual scales. Based upon that, we have optimized the design. As a result, we have delivered our products to treatment facilities all over Japan.
Features of the system
The deep aeration tank has the following features in comparison with a standard tank:
- Requires less land area.
- Aeration depth can be set at the same level as with the standard tank. In that case:
- You can use the blower of a standard tank.
- The quality of the treated water is the same.
- The oxygen transfer level per unit power is higher.
- Agitation characteristics are equivalent after installing a baffle plate, etc.
- By increasing the aeration depth, oxygen transfer efficiency can be increased.
- By using the ceramic air diffusion plate and diffusion cylinder for the diffuser of a deep aeration tank, high treatment efficiency is achieved in a stable manner.
