Skip to main content

Hitachi

Hitachi Infrastructure Systems (Asia) Pte. Ltd.

The submergible aerator is an underwater mechanical aerator and agitator that contributes to energy conservation at sewage treatment plants.

Overview

The submergible aerator is an underwater mechanical aerator and agitator that has independent oxygen supply functions and in-tank agitation functions, which are the two major functions of aerators. This device has undergone technical evaluation by the Ministry of Land, Infrastructure and Transport.

Features

  1. High oxygen dissolving efficiency
    The diffusing rotor, which is driven by the same axis as the impeller, refines the air bubbles that are generated by the air blown from the blower, and the impeller creates a complete gas-liquid mixture from the waste water and fine air bubbles. The gas-liquid mixture containing fine bubbles is released from the draft tube, becomes a radial flow, and circulates throughout the tank. This makes the residence period longer, achieves a high oxidation dissolving efficiency, and reduces the necessary blower capacity.
  2. Large agitation force with small amount of power
    The impeller, which is directly connected to the underwater drive, has a speed reduction mechanism that causes the impeller to be driven with a large amount of torque, which leads to the achievement of large agitation plant force with a small amount of power. For this reason, the flow velocity at the bottom of the tank is fast, which prevents sludge from settling to the bottom in a wide area inside the tank.
  3. Flexibility for load fluctuations
    The agitation and oxygen supply functions are independent, which means that the amount of oxygen supplied can be adjusted by increasing or decreasing the amount of air. Also, a wide range of adjustments can be made by controlling the number of operating units, which provides flexibility for load fluctuations.
  4. Can also do anaerobic treatment
    If the air supply stops, only agitation will be performed, which means that the system can be applied to anaerobic treatment and denitrification treatment, etc.
  5. Can be applied to various tank shapes
    The water circulation flows radially and vertically, so the system can be applied to various tank shapes, such as round or rectangular.
  6. Easy installation and maintenance
    There is no need to anchor a device to the bottom of the tank, and it is a lifting type, so installation and maintenance are easy.
    There is also flexibility for changing locations.
  7. Applicable for cold regions
    This system creates less of a temperature decrease in the waste water than surface aerators do, and the main unit is completely submerged, so it can be used in freezing weather, snow, and strong winds.
  8. Prevents secondary pollution
    Our system doesn't cause noise, odors, or airborne droplets like surface aerators do, and can prevent secondary pollution.

(in-house comparison)

System & device summary

The impeller is directly connected to the underwater drive, which gives the system a large agitation force. The diffusing rotor, refines the air bubbles that are generated by the air blown from the blower, and the impeller creates a gas-liquid mixture from the waste water and fine air bubbles.

Photograph: Submergible aeratorPhotograph: Submergible aerator CG
Submergible aerator, underwater mechanical aerator and agitator

Fields of application

  • Various reaction tanks