Dissolved Oxygen Meters

A low level of dissolved oxygen may also indicate high levels of pollution. The dissolved oxygen levels in water is measured using special types of devices known as dissolved oxygen meters. These meters are used in water and wastewater treatment applications and have been successfully tested for their desired performance.

Why is Dissolved Oxygen Measurement Important for Wastewater Treatment?

Solid and liquid waste is separate as a part of wastewater treatment. This separation is completed through two stages – primary and secondary treatment. In the primary treatment, large solids are removed from wastewater and dissolved and suspended solids are removed during the secondary treatment. Sewage microorganisms are introduced to the wastewater in the secondary treatment.

This process is usually accomplished using an aeration tank or the trickling filter. Sewage microorganisms are introduced to sludge and mixed with air. This air activates microorganisms and help them convert organic wastes into inorganic byproducts. Dissolved oxygen (DO) is used for this purpose. If DO concentration is low then these microorganisms may be dead and do not perform as required. Thus, DO concentration in water is tested regularly in wastewater treatment plants using dissolved oxygen meters.

Factors That May Affect DO Concentration in Water

The DO concentration in water may be affected by the following factors.

• Temperature: DO in water may be affected by temperature variations. The DO concentration may get low at high temperatures and vice-versa.  
• Salinity: Many solid wastes produced during processes may contain high level of salt. This salt carries charge, which may be attracted to water molecules in the solution 
• Pressure: Dissolved oxygen is affected by atmospheric pressure. When the atmospheric pressure increases the partial pressure of oxygen increases and vice-versa.  
• Humidity: DO level in water may be affected by water vapor or humidity. The partial pressure of oxygen increases with increasing humidity, and vice versa. 

Methods of Measuring Dissolved Oxygen in Water and Wastewater Plants

Dissolved oxygen is measured in various ways, including iodometry, colorimetry, and electroanalytical methods. In this, iodometry and colorimetry are often performed in lab settings, and are one-time measurement techniques, with limited possibilities. However, most process owners rely on electroanalytical methods for oxygen measurement. They feature polarographic and galvanic oxygen probes. These oxygen probes work on the principle of oxidation and reduction.

These probes are attached to dissolved oxygen meters. There are two types of meters used – portable meters and benchtop meters. Among these, portable meters are compact sized and can be used anywhere. These meters vary in testing method, function, and design. Our selection features portable dissolved oxygen meters, which have been extensively used in water and wastewater treatment plants.

How Do Dissolved Oxygen Meters Work?

The dissolved oxygen meters feature a probe or sensor and permeable or semipermeable membrane. The amount of oxygen diffuses across a membrane into a sensor or probe. When the oxygen reaches the sensor, a reduction reaction occurs, and an electrical signal is produced. This signal produces a readable measurement on a meter.

How to Choose the Right Dissolved Oxygen Meter for Your Application

Choosing the right DO meter can be a daunting task. The following tips will be helpful in this context.

• Application Requirements: Where do you plan to perform the dissolved oxygen measurement –in the lab or the field? How much water volume will be measured? You considerations would depend on these answers.
• Ease of Use: Although all DO meters are designed to measure the dissolved oxygen, they may not be easy to use. Some may require specialized training and need to be handled only by experts, so, ensure to focus on the ease of use whenever choosing the model.
• Data Accuracy: Dissolved oxygen measurements will help users to decide upon the course of water treatment. So, you need to check on the data accuracy prospect. You can do some online research and read the technical information carefully to see the movement of DO meter required to make accurate measurements.
• Total Cost of Ownership: This consideration would involve the acquisition price and cost of maintenance.

Water treatment is essential to ensure the availability of pure water to a large population. This water treatment is performed at different levels. To ensure proper fulfillment, it must be performed using the right quality equipment. Being at the forefront of water treatment technologies for several years, we understand the importance of offering quality equipment. This is why we have carefully included only the best equipment in this category and across all categories of water treatment equipment.

These equipment are included after much careful consideration and proven to perform in their work environments.  With so many product options under this and each category, the selection of the right equipment can be overwhelming. Our experts will work closely with you and guide you through all phases of selection. Contact us today to discuss the product listed on this page or other categories. We would be happy to serve you.