Designing an aeration control system: tips & tricks
A good control mechanism will help you to ensure a constant and precise amount of air is added to the water. Easy control of your air blowers will help you achieve a more efficient process. But before you start looking at the different control options, it’s a good idea to think about the needs of your system.
What to consider when designing your control system
Is the dissolved oxygen the only parameter you want to consider?
In that case, a simple process controller might suffice. If you’re considering other effluent quality parameters as well, you’ll need a more sophisticated control system.
Will you program your blowers in a cascade sequence?
Programming your blowers to kick in one after another when the demand increases is a popular way of setting up an aeration control system. You will likely work with multiple units and program them so that the next blower starts operating once the previous one(s) can no longer fulfill the flow requirement. Although opting for a different setup requires more programming, it does allow for better control of your process.
How do you guarantee redundancy if a blower is unavailable?
As we noted above, reliability and ensuring a consistent supply of air are crucial for wastewater treatment plant operators. That means your compressed air system needs some sort of redundancy if a blower becomes unavailable. Whether it’s because of some sort of problem or maintenance, your controls must ensure that your entire operation doesn’t suffer if one blower fails.
Do you want to use the stand-by blower to balance out running hours?
Some companies prefer to just have a designated standby blower in reserve. But with the right controls, you can also rotate which one of your blowers is the standby unit. This equalizes running hours and reduces wear and thus the required maintenance.
How do you maximize the efficiency of the installed equipment?
The right design not only guarantees the reliable operation of your blowers. It also ensures that you are running your blowers as efficiently as possible. Each blower has an optimal running point, at which it will run at peak efficiency. The further away from this point, the less efficient your process. Advanced central controllers will select a combination of blowers that can operate as close as possible to this sweet spot. This will minimize emissions and energy costs.
Finding the control options you need
The questions above will help you define the right layout in terms of the number of blowers you need for your plant and per basin. Of course, it is more complex than that. Have you asked yourself:
- How you’ll switch blowers between different basins?
- How you’ll accommodate a planned plant extension?
- Which data you’ll want to be available and monitored in the SCADA system?
- Which automatic reporting should be generated on regular basis?
Once you have asked yourself these questions and come up with the optimal answers for your operation, you can take the next step in your system design. One of those next steps would be looking at the control options for your aeration units. There are different options and control levels available. Unit control, remote monitoring, and central control options all allow you to better control your aeration system.
