11/10/2026
Reducing the operating cost of a water or wastewater treatment plant is not only about reducing chemical consumption.
Energy management can be just as important.
And the real question is not:
“How much electricity does the plant consume?”
It is:
“Is every KWH being used as efficiently as possible?”
In many water, wastewater and industrial wastewater treatment plants, electrical energy represents one of the major operating costs.
In biological treatment systems, aeration can often be one of the largest energy consumers, potentially accounting for around 40–60% of total electricity consumption, depending on the biological process, system design and operating conditions.
That means even a relatively small improvement in aeration efficiency can have a direct impact on annual energy costs.
Consider a simple example:
A plant consumes: 2,500 kWh/day
At an electricity cost of: $0.20/kWh
Daily energy cost: $500
Monthly: $15,000
Annual: $182,500
Now imagine reducing energy consumption by just 15%, without compromising treated-water quality.
Potential annual saving: $27,375
And this is for just one plant!
For larger facilities, the potential savings can become significantly higher depending on plant capacity, energy prices and the improvements implemented.
So where can energy be lost?
During technical assessments, some of the biggest opportunities can come from how equipment is operated, not necessarily from replacing the equipment itself.
Common examples include:
• Running pumps at maximum capacity despite lower flow rates
• Operating more blowers than required
• Not using Variable Frequency Drives (VFDs) where appropriate
• Reduced efficiency of air diffusers due to fouling or aging
• Manual rather than optimized control of Dissolved Oxygen (DO)
• Poor preventive maintenance of motors, pumps and bearings
• Excessive pressure losses within air distribution networks
How can energy efficiency be improved?
✔ Monitor energy consumption for each major operating unit
✔ Use sub-metering for key equipment
✔ Establish Energy KPIs
✔ Optimize blower operation according to the actual process load
✔ Control DO according to biological process requirements
✔ Use high-efficiency pumps with speed control where appropriate
✔ Implement preventive and predictive maintenance
✔ Conduct periodic Energy Audits to identify hidden losses
And there is one KPI every Plant Manager should keep an eye on:
Energy Consumption per m³ Treated — kWh/m³
Instead of looking at the electricity bill alone, this indicator helps evaluate how efficiently the plant is treating water, compare performance over time, and identify opportunities for improvement.
Because operational excellence is not simply about meeting discharge requirements.
It is about achieving the required treatment performance with:
Lower Energy Consumption.
Higher Operational Efficiency.
Longer Equipment Life.
Lower Total Operating Cost.
When evaluating your plant's performance, are you tracking kWh/m³ — or only the monthly electricity bill?
