Pump applications · Wastewater
Pumps in Wastewater
From raw sewage intake to treated effluent and biosolids.
A treatment plant runs a dozen distinct pumping duties, each with different solids, chemistry and flow. Getting the pump type right at each stage is the difference between a plant that runs untouched and one that blocks, cavitates or corrodes.
Pump types
Which pump does what
Submersible non-clog
Pump stations & raw intake
Solids-handling impellers (vortex or single-channel) pass rag and debris. The default for wet wells, inlet works and stormwater — installed on guide rails for easy withdrawal.
End-suction centrifugal
Clean transfer & RAS/final effluent
Efficient, low-cost transfer of screened or treated water — final effluent, service water, and return activated sludge where solids are modest.
Progressive cavity
Sludge & dosing
Constant flow regardless of pressure, gentle on flocculated solids. The workhorse for thickened/digested sludge, biosolids and viscous polymer feed.
Progressive cavity (dosing)
Chemical metering
Precise, pulsation-free dosing of coagulant, lime, ferric and polymer — flow proportional to speed for accurate chemical control.
Wide-throat PC / cake pump
Dewatered cake
Rectangular hopper with a feed screw forces dewatered cake (15–35% DS) from centrifuges and belt presses into the pump.
Duty guide
Matching the pump to the job
| Application / duty | Typical pump type | Why |
|---|---|---|
| Raw sewage / wet well | Submersible non-clog | Free passage for rag and solids; duty/standby with auto changeover. |
| Storm / flood pumping | Submersible or split-case | Very high flow at low-to-moderate head; intermittent duty. |
| Final effluent transfer | End-suction centrifugal | Clean water, high efficiency, low cost per litre. |
| Return activated sludge (RAS) | End-suction / submersible | Moderate solids, gentle handling to protect biology. |
| Thickened / digested sludge | Progressive cavity | Viscous, variable solids — constant flow against rising pressure. |
| Dewatered cake | Wide-throat PC | Hopper + feed screw force-feeds high-DS cake. |
| Polymer / coagulant dosing | PC dosing pump | Accurate, pulsation-free metering proportional to speed. |
Key considerations
What to get right in wastewater
- Corrosion: hydrogen sulphide, chlorides and organic acids attack internals — specify 316 SS wetted parts and EPDM/FKM elastomers.
- Solids & rag: size the free passage to the largest expected solid; self-cleaning impellers cut blockages and callouts.
- Variable inflow: VFDs match pumps to diurnal and wet-weather flow, saving energy and reducing wear at part load.
- Reliability: duty/standby arrangements with automatic changeover keep stations compliant during maintenance.
- NPSH: check suction conditions on hot digester and long-lift duties to avoid cavitation.
Size a pump for your duty
Use our selectors to match a pump to your flow and pressure, or talk to our engineers about a complete skid.