MARWELL Environmental (Shanghai) Co., Ltd. considers the following key factors when selecting suitable tubular aerators:

I. Wastewater Treatment Process Requirements

Aeration Method and Intensity

For activated sludge processes demanding high oxygen transfer efficiency, tubular diffusers with superior aeration performance and microbubble generation are required. For instance, in aeration tanks treating municipal wastewater using conventional activated sludge processes, maintaining sufficient dissolved oxygen for microbial organic degradation necessitates diffusers with high oxygen transfer coefficients to ensure adequate oxygen supply per cubic meter of wastewater.

For processes employing intermittent aeration or low-intensity aeration, such as certain phases of the Sequencing Batch Reactor (SBR) process, tubular diffusers capable of flexible aeration intensity adjustment are needed. This allows aeration control tailored to different process stages (e.g., influent period, reaction period, sedimentation period).

Requirements for Mixing Effectiveness

When wastewater contains high concentrations of organic matter or exhibits poor flow characteristics, aerators must generate effective mixing during aeration. For instance, in anaerobic-aerobic combined processes treating high-strength organic wastewater, tube diffusers in the aerobic stage must not only supply oxygen but also thoroughly agitate the wastewater to ensure complete mixing of organic matter and microorganisms. In such cases, diffusers with moderate bubble rise velocity and the capacity to generate extensive water flow turbulence are suitable.

II. Wastewater Characteristics

Acidity/Alkalinity (pH Value)

If wastewater exhibits acidic or alkaline properties, tube diffusers with strong acid/alkali resistance must be selected. For instance, in electroplating wastewater treatment, where pH levels are typically low and acidic substances are present, diffusers capable of withstanding acidic environments should be chosen. This includes those with special rubber or plastic membrane tubes, which resist corrosion under acidic conditions and ensure the diffuser's normal service life.

For dyeing wastewater, pH levels may vary depending on dyes and processes, with some being alkaline. In such cases, the aerator material must remain stable in alkaline environments to prevent damage from chemical corrosion.

Temperature

When treating high-temperature industrial wastewater (e.g., from certain chemical industries), temperature can impact aerator performance. Aeration devices capable of withstanding elevated temperatures must be selected, as high temperatures can cause conventional aeration membrane tubes to age, deform, and compromise aeration efficiency.

Conversely, wastewater treatment plants in cold regions, particularly during winter when effluent temperatures are low, must consider aeration device performance in low-temperature environments. This includes selecting aeration membrane tube materials that maintain good elasticity and air permeability at low temperatures to prevent material hardening, brittleness, and reduced aeration efficiency.

Suspended Solids Content

When wastewater contains substantial suspended solids—such as fibrous matter in paper mill effluent—it may clog diffusers. In such cases, tubular diffusers with clog-resistant pores should be selected. Diffusers featuring anti-clogging designs (e.g., self-cleaning pore structures or larger pore sizes) are particularly suitable for these wastewater conditions.

III. Diffuser Performance Parameters

Oxygen Transfer Efficiency

This is a key indicator of aerator performance. Higher oxygen transfer efficiency means greater dissolved oxygen increase in wastewater under identical aeration duration and air supply conditions. Oxygen transfer efficiency varies across different types and brands of tube aerators. Generally, products with an efficiency between 20% and 35% should be selected, though specific values must be determined based on actual wastewater treatment processes and water quality requirements.

Air Delivery Rate

The air delivery rate determines the volume of air the diffuser can supply. Select tubular diffusers with appropriate air delivery rates based on the size of the wastewater treatment tank, wastewater volume, and microbial oxygen demand. For instance, a large municipal wastewater treatment tank with high flow rates and abundant microorganisms requires diffusers with higher air delivery rates to meet oxygen supply needs.

Pressure Drop

Tube diffusers generate resistance during aeration. Diffusers with lower pressure drop can operate at reduced pressure, lowering energy consumption of air supply equipment (e.g., blowers). Prioritize diffusers with minimal pressure drop to enhance overall aeration system energy efficiency.

IV. Installation and Maintenance Factors

Installation Method and Space Requirements

Select tube diffusers with appropriate installation methods based on the shape, depth, and layout of the wastewater treatment tank. For shallow tanks, horizontally mounted diffusers may be suitable. For deeper tanks or those with special wall structures, vertically mounted diffusers might be preferable. Additionally, verify that the installation dimensions and connection methods of the diffusers match the existing tank structure and air supply piping to avoid issues like insufficient installation space or connection difficulties.

Maintenance Difficulty and Cost

Selecting easy-to-maintain tube diffusers reduces operational costs. For instance, diffusers with removable and replaceable membrane tubes allow for simple repairs when damaged or clogged, requiring no complex tools or extensive labor. Furthermore, consider the service life and maintenance cycles of diffusers. Choosing high-quality, stable products may involve higher initial investment but minimizes long-term costs associated with frequent equipment replacement.