How to select an ETP or STP automation panel
Short answer: An ETP or STP panel is quite different from an RO panel because it runs several items of equipment together — ET pump, air blower, filter feed pump — and often a standby for each. The panel has to sequence them and switch automatically between working and standby units.
Astero ETP panels range from ₹17,850 for a basic controller up to ₹79,800 with an energy meter.
What runs in an ETP or STP
| Equipment | Function | How it runs |
|---|---|---|
| ET / raw sewage pump | From the collection tank onward | On level |
| Air blower | Aeration in the tank | Continuous or on timer |
| Filter feed pump | Treated water to the filter | On level |
| Sludge pump | Removing sludge | On timer |
| Dosing pump | Chemical (pH, chlorine) | On sensor or timer |
Each can have a different HP and phase, so a complete list is needed when the panel is built.
Astero ETP and STP panels
| Model | What it handles | Price |
|---|---|---|
| ETPMATIC / STPMATIC / SBRMATIC | Basic controller | ₹17,850 |
| ASTERO 333NG ETP | 3 units, all 3 phase | ₹26,250 |
| ASTERO 333NG ETP (W+S) | 3 units plus standby (6 total) | ₹43,050 |
| ASTERO WASTEWATER NXT 2.0 | With energy meter | ₹77,700 |
| ASTERO SBR NXT 2.0 | For SBR, with energy meter | ₹79,800 |
What 1W+1S means
1W+1S stands for 1 Working plus 1 Standby — each item of equipment has a spare installed.
The panel runs them alternately, for example one pump one day and the other the next. This means:
- Wear is shared evenly between the two
- If one fails the other takes over immediately and the plant does not stop
- One can be shut down for maintenance without stopping the plant
When the energy meter version is worth it
The ₹77,700 WASTEWATER NXT 2.0 has a built-in energy meter. The benefits:
- You can see the electricity cost — and work out cost per kilolitre treated
- Pollution boards often ask for energy data as well
- Blower load becomes visible — in an ETP the blower accounts for 60 to 70 percent of the electricity
If you only need to run the plant with no records to submit, this is not necessary. But on a large plant the electricity bill is high enough that monitoring alone produces savings.
Why SBR needs a different panel
In an SBR (Sequential Batch Reactor) everything happens in one tank but at different times — filling, aeration, settling and decanting. The whole cycle runs on timers with different valves and pumps at each stage.
The SBR NXT 2.0 therefore contains specific sequencing logic. A standard ETP panel cannot run an SBR.
Instruments to fit alongside
A panel alone is not enough in an ETP or STP. These are usually connected as well:
- pH controller — discharge pH must stay between 6.5 and 8.5, which is a regulatory requirement
- DO meter — dissolved oxygen in the aeration tank. Too little and the bacteria die
- Turbidity meter — outlet quality
- Electromagnetic flow meter — discharge flow, required by pollution boards. The reasons are in this guide
- Telemetry modem — to send data to the pollution board server
What to provide when ordering a panel
- The HP and phase of every pump and blower
- Which equipment needs a standby
- How many level switches, and where
- Whether dosing pumps are controlled from the panel or separately
- Whether an energy meter is required
- Whether pollution board monitoring applies
- Where the panel will be located — indoor or outdoor (outdoor needs IP65)
A common mistake — undersizing the panel
People often specify a panel for today's equipment and then add another pump or blower six months later, only to find there is no space in the panel.
Our advice: ask for 20 to 25 percent spare space in the panel. Adding one extra contactor later is far cheaper than replacing the whole panel.
Indicative costs
| Plant | Setup | Panel approx |
|---|---|---|
| 10–20 KLD STP | 3 units, no standby | ₹26,000 |
| 50 KLD STP | 3 units plus standby | ₹43,000 |
| 100 KLD ETP | Standby plus energy meter | ₹78,000 |
| SBR plant | SBR logic plus energy meter | ₹80,000 |
These are panel costs only — instruments, sensors and telemetry are additional.
Have your ETP or STP panel designed
Send the full list of pumps and blowers with HP and phase, and we will design the panel and quote it.
💬 WhatsApp par poochhein 📞 9910646957Frequently asked questions
Why is an ETP panel different from an RO panel?
An ETP runs several items of equipment together, such as an ET pump, air blower and filter feed pump, often each with a standby. The panel has to sequence them and switch automatically between working and standby units, which an RO panel does not do.
What does 1W plus 1S mean?
It means one working and one standby. Each item of equipment has a spare installed, and the panel runs them alternately. This shares wear evenly and means the plant does not stop if one unit fails.
When is the energy meter version worth buying?
On larger plants where the electricity bill is significant, or where the pollution board requires energy data. In an ETP the blower accounts for sixty to seventy percent of consumption, so monitoring alone often produces worthwhile savings.
Can a standard ETP panel run an SBR?
No. In an SBR everything happens in one tank at different times — filling, aeration, settling and decanting — which needs specific sequencing logic that a standard ETP panel does not have.
Why should spare space be left in the panel?
Because another pump or blower may need to be added later. With twenty to twenty five percent spare space only one contactor has to be added, whereas otherwise the whole panel has to be replaced, which is far more expensive.