When discussing aeration, the topic of efficiency often arises, but what does this really mean to those of us treating wastewater?

The word efficient means “achieving maximum productivity with minimum wasted effort or expense.” For wastewater treatment operators, this translates into minimizing wasted energy and energy expenses.

The high cost of energy is a common challenge in any type of aeration. It accounts for between 40 and 80 percent of a wastewater treatment plant’s energy demand.

Reducing energy demand can mean taking a hard look at equipment and the water being treated to see if key parameters such as dissolved oxygen and oxygen uptake rates are consistent and meet targets.

Replacing Water Treatment Equipment

Sometimes simply changing a few settings or using control systems can lead to better operating and energy efficiency. But sometimes, wholesale equipment replacement is a necessary step in meeting goals.

For example, the local water reclamation plant in Windsor, Ontario, recently installed new aeration equipment precisely to save energy. Despite the capital outlay for two new blowers, it’s estimated the changes will save CA$191,000 a year in electricity and maintenance repair costs.

Equipment manufacturers know this, so their newest products are designed with energy efficiency in mind. In an article on LinkedIn, Dewitt Dees, CEO of RWL Water North America, explains:

Our Tornado® aerators, for example, are outfitted with an energy-efficient motor to reduce energy costs. They also feature either soft-start or variable-frequency drive controllers, which not only reduce energy use, but also may eliminate penalties associated with power surges. Additionally, our solar-powered Eco Aeration™ products — which can be used in ponds, lakes, and reservoirs for algae and odor control — don’t need an external power source, and their operational efficiency can reduce the cost of conventional chemical treatments as well.

Challenging Effluents

Challenging effluents may be more than existing aeration can handle efficiently. In these cases, continuing to operate could mean failing to meet targets, which could lead to more expenses and even fines.

One example is the effluent produced by the paper and pulp industry. When treating it, the buildup of sludge in basins is a big problem. Effectively treating this wastewater may require more thorough mixing.

But conventional aeration has its limits, dissolving no more than 25 percent of available oxygen into wastewater. Such systems continue to use energy even when it’s not needed, and it’s complicated to ramp equipment up and down to meet demand, or take individual aeration units on and off line.

Pure Oxygen Aeration

This is when pure oxygen aeration may prove useful. It was developed on the theory that adding pure oxygen to the aeration process would accelerate biological processes by increasing the dissolved oxygen available to microorganisms.

New technologies for providing pure oxygen aeration during wastewater treatment have reduced total power demand by as much as 60 percent, compared to a conventional system.

RWL Water offers a wide range of aeration solutions, drawing from its decades of experience across a wide range of industries and applications. How can we help solve your next water, wastewater, or energy challenge? Please contact us with any questions or to request a quote.

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