Diffused Aeration for Wastewater Plant

Two most common methods of aeration system used in wastewater treatment plants involve either the use of Submerged Diffusers by introducing air or oxygen into the wastewater or another approach is by mechanical agitation. Both methods can be relied upon to provide good aeration for your pond water but for our discussion here, the topic will only be focused on using submerged diffusers.

The idea on using a Diffuser System is to mainly introduce air into the wastewater and the efficiency will depend on whether the air bubbles are those fine or coarse large bubbles. Therefore, with that consideration in mind, submerged air diffuser system can be further divided into porous or nonporous and other types like jet aeration, which will also be discussed here.

Porous diffuser
Porous diffuser comes in different shapes such as plates, discs, domes and tubes. Plate diffusers are mounted on an aluminum plate holder consisting of 6 or more plates with each connected to air supply piping controlled by valves. For discs, domes and tubes diffusers, each of these are screwed onto air supply manifolds instead and it usually runs across the length of tank or forms a grid beneath tank bottom.

Non-porous diffuser
Non-porous diffuser produces larger air bubbles and is mainly made up of fixed or valve orifice type of diffusers. Though the system has much lower efficiency, somehow these are often offset by the lower maintenance and setup cost. Other types of non-porous include a static tube aerator whereby air is introduced from the bottom of submerged plates.

Jet aeration
Jet aeration basically relies on liquid movement using pumps for wastewater circulation and then within the system, introduced into it compressed air by using a nozzle. The setup here is highly suitable especially for deeper tanks and for achieving more uniformed aeration. This type of diffusion device is capable of having high air to liquid transfer efficiency but however, the setup cost maybe slightly higher due to the type and sizing of pumps required including maintenance of air compressors.

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