High-pressure pumps for ZLD and MLD reverse osmosis applications

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Robust, energy-efficient high-pressure pumps for industrial wastewater treatment

As water reuse and recycling grow alongside stricter environmental controls, companies and utilities increasingly turn to liquid discharge (ZLD) and minimum liquid discharge (MLD) to treat industrial wastewater. And because ZLD based solely on traditional thermal processes is highly energy intensive, membrane processes using reverse osmosis (RO) have emerged as an essential part of ZLD. Indeed, studies show that RO pre-treatment can reduce ZLD’s overall energy consumption by up to 75%.

Danfoss APP pumps are particularly well-suited for such RO treatments. Due to their unparalleled efficiency rates of up to 92%, they reduce OPEX and emissions significantly compared to other high-pressure pump technologies. Moreover, this efficiency remains the same regardless of varying pressure rates up to 120 bar, and operators can depend on their field-proven history of simple maintenance and long service intervals. The new APP pumps with ceramics makes the Danfoss portfolio of reliable, energy efficient high-pressure pumps for wastewater treatment ideal for even more use cases. Monitoring system available for all APP pumps with ceramics.

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

Customer collaboration contributes to pump innovation

Customer collaboration contributes to pump innovation

Danfoss developed its latest APP high-pressure pump with ceramics in close cooperation with customers, including Veolia Water Technologies and TEMAK. Read our latest article to learn how demanding field tests help ensure reliability.

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

Processes Illustration

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 30 and APP 38 with Ceramics English Multiple 10 Jan, 2024 2.0 MB .pdf
Promotion material APP high-pressure pumps with ceramics: Robust energy efficiency for demanding membrane technologies English Multiple 12 Jan, 2024 1.4 MB .pdf
Article APP pump now with ceramics for energy efficient SWRO and wastewater treatment English Multiple 05 Dec, 2023 1.1 MB .pdf
Data sheet APP W HC 15-24 Pumps Data sheet Chinese (CN) China 10 Apr, 2019 1.2 MB .pdf
Data sheet APP W HC 15-30 Pumps Data sheet English Multiple 22 Oct, 2019 753.5 KB .pdf
Brochure Save water, time and money with the new Danfoss APP W HC pump English Multiple 16 Jan, 2019 1.9 MB .pdf
Brochure Save water, time and money with the new Danfoss APP W HC pump English United States 16 Jan, 2019 1.9 MB .pdf

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