The three best positive displacement pumps for wastewater treatment

Pumps in Water Treatment Plant - the best solutions of NETZSCH


NETZSCH pumping systems enable efficient pumping in wastewater treatment plants

Wastewater places very high demands on the pumping system in some applications. We provide you with an overview of the various positive displacement pumps and their respective advantages.

Pumping systems face various challenges, from communal water treatment to industrial wastewater treatment plants. On the one hand, they are often faced with challenging conditions. This is mainly because the wastewater is often contaminated with wet wipes or other solids, resulting in a high risk of clogging and system failures. In addition, wastewater has a very abrasive and wearing effect. On the other hand, economic factors are increasingly coming into focus. Rising energy prices are putting more and more pressure on operators in terms of system optimisation and cost reduction. The choice of the appropriate pump technology is of decisive importance here. Positive displacement pumps, in particular, can score points in this context.


Rotary lobe pumps for pumping wastewater with a high solids content

The rotary lobe technology uses two lobes that move against each other, creating a vacuum on the suction side and sucking in the medium. The medium is pushed through the delivery chambers to the discharge side. Since the delivery chambers are self-contained, the rotary lobe pump can easily handle high solids content. Compared to centrifugal pumps, there are no large centrifugal forces or shear forces acting on the fluid when pumping liquids with rotary lobe pumps. Therefore, even abrasive media can have relatively little effect on the pumps' housing and rotary lobes.


The TORNADO® T.Envi® from NETZSCH is particularly suitable for conveying media containing solids

In addition to the technology-related advantages, the TORNADO® rotary lobe pump from NETZSCH offers several other aspects that distinguish it for use in the wastewater sector. The NETZSCH unit is characterised by a highly compact design. This is a decisive advantage, especially when retrofitting systems with little space available for replacement. Depending on the model, NETZSCH also uses extremely robust materials, making the models very resistant to wear and tear and resulting in extended service lives. The well-thought-out FSIP® design (Full Service in Place) with easy access to the inside of the housing, which is possible without special tools, makes maintenance child's play.


Progressing cavity pumps ensure long service lives in wastewater pumping

In progressing cavity technology, a helical rotor turns against a stator. This creates delivery chambers between the rotor and stator, which move the medium from the inlet to the discharge side.

Due to their design, the delivery chambers of a progressing cavity pump are smaller than those of a rotary lobe pump. This means that rotary lobe technology is more recommended for large solids. However, due to the stator-rotor principle, progressing cavity pumps offer almost no possibility of clogging.

NEMO® progressing cavity pump in FSIP® design
The NEMO® progressing cavity pump in FSIP® design increases the service life up to three times

The NEMO® progressing cavity pump from NETZSCH, like the TORNADO® rotary lobe pump, offers service-friendly maintenance. The so-called Full Service in Place Principle (FSIP) enables complete pump service without dismantling. This saves you up to 66 percent in working time. In addition, NETZSCH offers the xLC® stator adjustment system, which significantly reduces wear on stators. The stator can be axially compressed when worn with just a few simple steps. This restores the optimal sealing line between the stator and rotor and keeps the pump performance at a constantly high level. The pump's service life can thus be extended by up to three times.


Simple principle, highly effective: Hose pumps for sewage pumping

Peristaltic pumps are a simple but effective type of positive displacement pump. A hose, which is placed in a pump housing, is squeezed with the help of rollers. The rotation of the rollers causes the pinch point to move along the hose, thus propelling the pumped medium.

Like the positive displacement pumps already mentioned, peristaltic pumps are particularly suitable for wastewater pumping because of their tolerance of high solids or fibre content of up to 70 percent. The exceptionally high suction capacity distinguishes these pump systems primarily for the transport of sewage sludge. The low shear rate additionally prevents foaming of the medium.

PERIPRO peristaltic pump from NETZSCH
The PERIPRO peristaltic pump from NETZSCH excels in sewage sludge pumping

Due to their unique design with XXL rollers, the PERIPRO peristaltic pumps from NETZSCH are suitable for high pressure and, at the same time, have a high degree of efficiency as well as low energy and lubricant requirements. The design-related low sensitivity to abrasion and a shallow risk of clogging speak for using the peristaltic pump in the wastewater sector. The robust hose is the only wearing part, which reduces maintenance times to a minimum. Compared to conventional peristaltic pumps, the low lubricant requirement also makes the PERIPRO more economical.


Grinding systems for pump protection in wastewater conveyance

The continuously increasing proportion of wet wipes in wastewater treatment can be counteracted with the help of various grinding systems and the appropriate pumping system.

Grinders can be divided into cutting plate macerators and twin-shaft grinders. With grinding using a cutting plate - as with the M-Ovas® from NETZSCH - solids are sucked up to the cutting plate by the flow. Larger parts accumulate in front of the cutting plate and are ground by the cutter head until they fit through the openings. This additionally protects downstream pump systems from clogging. The cutting plate is flexibly exchangeable, allowing you to determine the degree of grinding yourself.

M-Ovas® cutting plate macerator from NETZSCH
Supports your pumping system in wastewater conveyance: The M-Ovas® cutting plate macerator from NETZSCH


The N.Mac® twin shaft grinder from NETZSCH is suitable for particularly coarse and solid contaminants. Even textiles or plastic waste are easily ground through two powerful knife blocks. Different combinations of blades determine the degree of grinding.

N.Mac® twin shaft grinder from NETZSCH
The N.Mac® twin shaft grinder from NETZSCH is used for particularly coarse solids

Traditionally, centrifugal pumps are used to pump wastewater. However, this technology has an increased risk of clogging, so it quickly reaches its limits. Therefore, it is worth looking at the above-mentioned positive displacement pump systems, which offer numerous advantages - especially when dealing with media containing solids.


As the specialist in pumping complex media, NETZSCH Pumps & Systems is your first point of contact. Plants for efficient wastewater treatment are part of the critical infrastructure - with pumps from NETZSCH, you ensure that the pumping of wastewater is always non-critical. The experts at NETZSCH will be happy to advise you in more detail!

From May 30, 2022 to June 3, 2022 you can meet NETZSCH at the IFAT in Munich at booth 451/550 in hall B1. Free tickets are available here!



Source & Pictures: NETZSCH

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