Submersible Pumps for Septic Tanks and Wastewater Treatment Systems

Biological wastewater treatment systems such as SBR (sequence batch reactor) and Fixed-bed (reactor) Wastewater Treatment are the norm for decentralised remote wastewater treatment. While modern biological wastewater treatment systems operate with a combination of sedimentation stages and oxygen-input to achieve the highest treatment levels, septic tanks operate only by means of staged sedimentation.

The treated wastewater within the final chamber, also referred to as effluent, is in a functioning treatment system or septic tank free from solids and discolouration with saturated raw sewage elements.
This relatively clear effluent can then be discharged towards the percolation area, where the natural infiltration within an underground gravel-bed as well as lower lying soil- & ground-layers further cleanse the effluent water before it reaches the groundwater reservoir.

Every private dwelling and commercial building not connected to the municipal sewerage network is obliged to adequately treat raw sewage and wastewater in a decentralised remote wastewater treatment system or septic tank.

Why is a submersible pump necessary within a septic tank or wastewater treatment system?

Unless the site landscaping conditions allow the final chamber to naturally overflow towards the percolation area or subsoil polishing-filter, a submersible wastewater pump is required to discharge the treated effluent. Reoccurring level-controlled discharge of the final chamber ensures the wastewater treatment system or septic tank can operate without any backlog or overflowing.

Pumps for septic tanks / treatment systems with Float Switch

Most submersible sump pumps installed in a septic tank or wastewater treatment system are equipped with a float switch, which allows the pump to switch ON/OFF fully automatically according to the level within the final effluent chamber.

Pumps for septic tanks / treatment systems without Float Switch

Some wastewater treatment systems could be equipped with a control panel, which switches the pump directly (not common in Ireland or Northern Ireland). In these cases, a pump without a float-switch is required.
Usually, an external device (float switch or similar) is connected to the panel, which then prompts the panel to switch the submersible pump level-controlled. The advantage of such a setup is that the panel could also monitor operational-hours and switching-cycles of the pump.

As the majority of wastewater treatment systems and septic tanks are located at private domestic facilities and small commercial locations, most submersible wastewater pumps used at these installations are in single-phase (230V/50Hz). Some commercial systems with greater volume demand may however be equipped with submersible pumps in three-phase (400V/50Hz).

In the event of a septic tank pump replacement, check the technical details of your existing pump to identify a suitable alternative below. If you require assistance in identifying the correct submersible pump for your treatment system, please contact us.

GUIDE – Wastewater Treatment Systems