Sludge Pumps for Wastewater

Rotary lobe sludge pumps for heavy wastewater handling

Vogelsang offers the ideal sludge pump for wastewater applications requiring a positive displacement pump. A rotary lobe pump, properly configured with our exclusive HiFlo rotor design, can move heavy wastewater sludge containing solids, abrasives and debris throughout your system with ease. It’s great for feeding dewatering equipment by producing a pulsation free flow of sludge to your belt press, centrifuge or other dewatering device. It’s also great for pumping primary and secondary sludge, WAS, TWAS, RAS, FOG and DAF.

For those used to high-maintenance progressing cavity pumps, switching to a Vogelsang sludge pump can reduce maintenance man-hours up to 90%! Vogelsang pumps offer quick and easy access to the wet end for inline preventative maintenance or repair without disturbing any connected piping. One person can complete a typical wet end rebuild in about an hour.

It’s also less expensive to operate in terms of spare parts. Rotary lobe pumps are physically much smaller than progressing cavity pumps of the same capacity. This translates into smaller components that are easier to handle and less expensive.

The diagram and application profiles below shows common applications for Vogelsang sludge pumps and reasons you should consider a Vogelsang rotary lobe pump for your next new or retrofit project.

Where to use a Vogelsang Sludge Pump...

Sludge Pumps for Wastewater Applications: Primary & Secondary Sludge, WAS, RAS, TWAS, FOG, Scum, Septage, Thickened Sludge. High solids sludge pumping.

Primary Sludge Pumps

Primary & Secondary Sludge

Primary & Secondary Sludge are typically where we find the heaviest concentration of grit and floatable non-organic debris in the wastewater plant. The solids content is usually low; typically 1%-3% solids. Harder materials of construction are often chosen for the wet end along with abrasive-friendly elastomers for the lobes. Typical operation is best if the pump pulls a constant low flow of sludge versus intermittent off-on operation. More about Primary Sludge, Secondary Sludge

Waste Activated Sludge Pumps. WAS Pumps

Waste Activated & Return Activated Sludge

Activated sludge requires the ability to pump varying viscosity. WAS & RAS is typically mild because the majority of the grit has settled out. The main challenge in pumping WAS or RAS is that it often contains high amounts of entrained air which can cause cavitation. Our gooseneck flanges keeps the pump primed and avoids air locking. Standard materials of construction are sufficient for most applications including NBR lobes and either cast iron or Astempered Ductile Iron (ADI). More about WASRAS

Thickened Sludge Pumps. TWAS Pumps. Digested Sludge Pumps.

Digested & Thickened Sludge

Digested & Thickened Sludge applications are very common in wastewater plants that have use either anaerobic or aerobic digestion. These applications are normally between 3-8% solids with light to medium abrasive with solids such as hair and rags. The right rotor elastomer is very critical. Digested sludge applications require a low pulsation flow when feeding dewatering equipment. The lower the pulsation, the more accurate polymer dosage can be applied. More about Digested Sludge.

Dewatering Sludge Feed Pumps

Dewatering Feed

Our pumps have been widely chosen to feed dewatering equipment such as Belt Press, Centrifuge and Gravity Belt Thickeners. This is largely due to the pumps ability to deliver sludge to the equipment evenly with no pulsation. An even flow of sludge to the dewatering equipment helps the equipment run as efficiently as possible and with less polymer. Additionally, it's compact and easy to fit or retrofit onto the same skid as the dewatering unit itself.

Dissolved air flotation tank sludge feed pumps. DAFT pumps.


DAFT applications are difficult not only because of the entrained air, but also the thickness of the sludge. Vogelsang pumps are designed for pumping viscous liquids containing heavy solids. A slower operating pump coupled with a wide range of available elastomers is critical. These applications require low speed in order to keep the pump from excess cavitation due to air pockets building in the cavities of the pump.  Additionally, you can encounter floating solids, hair and rags that can build-up over time.

Scum pumps. Scum sludge pumps.

Scum & Septage

Scum is usually saturated with air and loaded with inorganics (floatables). Pumping high concentrations of floatables without sufficient water to move the solids is difficult due to the lack of conveyance. Even though flows are typically pretty low, an oversized pump running slow will allow larger solids. Septage pumping can sometimes be the most difficult application in a wastewater plant, and normally ranges from .5-1% solids and contains grease, hard solids, hair, rags, and other solid wastes.