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How to Manage Wastewater Mixing Energy

By: Tom Frankel
Post Date: Giugno 29th 2023

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wastewater treatment plant operator

How to Manage Wastewater Mixing Energy

A wastewater treatment plant’s energy consumption largely depends on the type and amount of contaminants in the water and the methods used to remove them.

Whether a facility has minimal or considerable wastewater treatment requirements, energy efficiency is something every plant should practice. Even something as simple as changing the type of aeration system they use or tracking their energy consumption can make a world of difference in usage and costs.

Seeking more energy-efficient practices during wastewater treatment can help plants reduce their water usage, thus decreasing their utility bills. How can we control wastewater to strengthen energy efficiency? Keep reading for tips to improve wastewater mixing energy.

How Much Energy Does a Water Treatment Plant Use?

According to the Environmental Protection Agency, wastewater treatment plants are among the largest energy consumers, using 30-40% of the total consumed energy in municipal governments.

In the United States, wastewater and drinking water systems account for about 2% of energy use, contributing over 45 million tons of greenhouse gases annually. Municipalities can reduce this usage by 15%-30% by incorporating energy-efficient practices into their water treatment plants, saving thousands of dollars.

wastewater mixing energy is the energy used from mixing air into wastewatere

What Is Wastewater Mixing Energy?

Wastewater mixing energy is the energy used from mixing air into wastewater, or aeration. Aeration is a quick and efficient process for wastewater treatment. It combines oxygen with the wastewater, helping aerobic bacteria break down organic waste faster.

However, aeration requires electricity that can consume 25-60% of the plant’s power. Naturally, large facilities with heavy mixing requirements have high amounts of wastewater mixing energy. Their surface aerators can use many kilowatts of electricity each hour.

How to Improve Wastewater Mixing Energy

How can wastewater treatment plants be improved in terms of energy usage? Wastewater treatment facilities can boost their energy efficiency in multiple ways, such as:

Here are several wastewater mixing energy tips facilities can incorporate into their daily operations.

1. Use a Fine Bubble Diffuser

A fine bubble diffuser creates oxygen bubbles, which nourish microorganisms during aeration. Aeration relies on bubble diffusers to deliver oxygen to beneficial bacteria that break down organic matter. Plant managers should select the proper diffuser to ensure efficient operation.

The fine bubble diffuser’s membranes contain small holes, providing a higher density of holes. Small bubbles rise more slowly than large ones, enabling higher oxygen transfer per volume of supplied air and maximizing bubble retention time. Small bubbles offer more surface area, which also improves oxygen transfer.

A fine bubble diffuser can decrease energy usage by up to 75%. Furthermore, fine bubbles produce 2% or more Standard Oxygen Transfer Efficiency during aeration, which is twice the amount that coarse bubble diffusers create.

2. Clean Wastewater Treatment Equipment Regularly

Equipment cleaning and maintenance help improve oxygen transfer levels, prevent fouling and increase aeration efficiency. Try to pressure-wash or scrub diffusers regularly. Plants can clean flexible diffusers by temporarily increasing airflow in the system. This increased airflow helps remove deposits from pores so diffusers can remain flexible.

3. Use Large-Blade Mixers

There are two main types of aeration systems — mechanical and diffused. While diffused aeration occurs at the bottom of a tank or lagoon, mechanical aeration occurs at the surface.

Unlike diffused aeration systems, which use small bubbles and flexible membranes, mechanical surface aeration systems use rotating shafts and propeller blades. They generally provide stronger localized mixing and higher dissolved oxygen concentration. However, they tend to be less efficient than diffused aerators.

Mixing technology has rapidly evolved, especially with increasing energy costs and intensive water treatment processes to meet state and EPA guidelines. When using mechanical surface aeration, wastewater and sewage treatment plants have started to shift from small- to large-blade agitators for more energy-efficient mixing.

A large-blade submersible mixer can yield the same mixing results as a small-blade mixer while using one-fourth of the power. Therefore, it can provide significant power savings with the low maintenance and longevity of a small-blade mixer.

4. Consider Diffused Aeration Over Mechanical

A diffused aeration system provides higher energy savings than a mechanical aeration device. Compared to mechanical aeration, diffused aeration pumps smaller amounts of less concentrated air into the water, ensuring a more energy-efficient process and complete mix.

Comparatively, a mechanical aeration system produces less surface area for oxygen transfer. It also distributes oxygen unevenly throughout the tank. Therefore, it offers less efficient aeration than a diffused system. The less efficient mechanical aeration process results in higher energy usage and costs.

Diffused aeration combines efficiency, durability and affordability, making it a practical choice for wastewater treatment plants looking to save energy and reduce expenses. Diffused aeration systems can support industrial and municipal systems around the world. Their technologically advanced design offers maximum value, while their durability and reliability provide optimal oxygen transfer.

5. Employ More Diffusers

The number of diffusers is an essential consideration regarding wastewater treatment systems. Using fewer diffusers can lower efficiency and increase costs. Meanwhile, using more diffusers helps plants disperse oxygen more evenly throughout the tank, improving efficiency.

6. Use an Energy Monitoring System

Plant managers can use an energy monitoring system to track and improve usage. Some examples include:

7. Don’t Use Too Much Aeration

Excessive aeration can negatively affect process performance, increase dissolved oxygen and waste energy. While dissolved oxygen is important for wastewater aeration, too much can hinder oxygen transfer efficiency and sludge settling.

choose ssi for all your wastewater needs

Choose SSI for All Your Wastewater Needs

Investing in durable, high-quality aeration equipment is a great way to improve energy efficiency during wastewater treatment. SSI Aeration, Inc. is a global leader in wastewater treatment product design and manufacturing. SSI’s wastewater treatment equipment is focused on integrated fixed-film activated sludge and moving bed biofilm reactor processes.

SSI’s diverse product line includes fine and coarse bubble diffusers, aeration systems, and PFTE and EDPM membranes. Providing innovative solutions for industrial wastewater and sewage treatment plants, SSI’s engineering department aims to ensure high energy efficiency and product quality with every development.

Contact SSI today to learn more about the solutions we offer.