High-pressure pumps for ZLD and MLD reverse osmosis applications

High-pressure pumps delivering up to 120 bar

When using a Zero Liquid Discharge (ZLD) or Minimal Liquid Discharge (MLD) system for treatment of industrial wastewater, a membrane-based process will help to reduce the energy consumption radically.

The membrane-based process, also known as reverse osmosis, requires membranes and a high-pressure pump that can operate with pressures up to 120 bar.

Membranes have been developed for pressures up to 120 bar and with Danfoss APP W HC pumps, professionals now also have access to a reliable and high-efficient pump that meets the requirements of the membrane-based process.

Features and benefits

World-class efficiency  - up to 90% at all operation points

Low complexity with few moving parts

Easy to operate and maintain

The pump is oil-free to avoid contamination

Easy scalability when coupled in parallel

Made of first-class Duplex steel to prevent corrosion in aggressive environments

Save water, time and money with the new APP W HC pump

Save water, time and money with the new APP W HC pump

Reduce the discharge of industrial wastewater by applying the highly efficient Danfoss APP W HC pump with an outlet pressure of up to 120 bar.

High-pressure pumps delivering up to 90% efficiency

With efficiency rates up to 90% at all operating points, the Danfoss APP W HC pumps are designed to produce the highest level of efficiency in ZLD (zero liquid discharge) and MLD (minimal liquid discharge) applications. The strong and extremely robust pumps are made of non-corrosive materials and guarantee high reliability and low operational costs over the service life. 

The pumps are positive displacement pumps with axial pistons that move a fixed amount of water in each cycle. Flow is proportional to the number of shaft revolutions (rpm). Unlike centrifugal pumps, the APP W HC pumps produce the same flow at a given speed no matter what the discharge pressure.

The simple pump design allows easy installation, inspection, and maintenance. Furthermore, the pump operates without oil to prevent contamination. The pumps can be parallel-coupled in trains to fulfill the required capacity at any time.

Pump animation

Pump animation

The axial piston pump has a simple design with only a few parts.

Learn how the pump works in this video animation.

Product range

APP W HC pump

The APP W HC pump comes in 4 sizes:

  • APP W HC 15: Flow from 11 to 15 m3/h (48-66 gpm)
  • APP W HC 21: Flow from 11 to 21 m3/h (48-92 gpm)
  • APP W HC 24: Flow from 11 to 24 m3/h (48-106 gpm)
  • APP W HC 30: Flow from 11 to 30 m3/h (48-132 gpm)

All pump sizes handle pressure up to 120 bar (1740 psi)

Download datasheet

Reverse osmosis process with significantly reduced energy consumption

Save energy with a membrane-based process

ZLD/MLD systems can be operated with different processes. A way to reduce energy consumption is to use a membrane-based process.


Type Name Language Valid for Updated Download File type
Data sheet APP W HC 15-24 Pumps Data sheet Chinese (CN) China 02 May, 2019 1.2 MB .pdf
Data sheet APP W HC 15-30 Pumps Data sheet English Multiple 20 Jun, 2019 697.9 KB .pdf
Brochure Save water, time and money with the new Danfoss APP W HC pump English Multiple 02 May, 2019 1.9 MB .pdf

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