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DeROs®: Energy Recovery System for RO (Reverse Osmosis) Desalination Plant

DeROs®: Energy Recovery System for RO (Reverse Osmosis) Desalination Plant

DMW Corporation

DeROs®: Auxiliary Mechanical
Device for Energy Recovery in
RO High-pressure Pump

Desalination of seawater by Reverse Osmosis (RO) membrane is a promising method to mitigate water shortage in emerging economies. However, RO process consumes much electricity for filtration of seawater, and operating cost is much higher than a general water purification of surface water.

DMW corporation provides an effective solution to this problem.  DeROs® is an advanced mechanical device to recover fluid pressure of brine and reuse it for the suction pressure of a high-pressure pump. Having ability of high efficiency, low pulsation, low noise, extremely low mixing rate and extremely low over-flush rate, DeROs® is environmentally friendly isobaric multi cylinder type energy recovery device for SWRO with wide and variable flow range to demand of freshwater.

Fig. 1 Basic concept of DeROs®

Product video (refer to the link and QR code below):




Major Features and Advantages

  1. DeROs®’s efficiency is as high as 98% or more, therefore High pressure brine can be reused, and power consumption of High pressure pump can be saved to about 50%.
  2. The operation of DeROs® can be adjusted to the amount of freshwater production by wide range.
  3. Over-flush rate and mixing rate are less than 1% respectively, and noise level is 75 dB(A) or less.
  4. Generally, one membrane unit is linked to one ERD (Energy Recovery Device; DeROs®) unit. However, DeROs® can be linked to multiple membrane units. Hence, maintenance of membrane unit is available without interrupting freshwater production.
  5. DMW can supply all equipment as a package, High-pressure pump, Booster pump and ERD.

- Webpage of DeROs®:

- Leaflet of DeROs®

Technology Data

Technology data

Possible applications

1: Safe and stable freshwater supply to the areas suffering from freshwater shortage.
2: Promotion of energy saving by improving the efficiency of seawater desalination plants.
3: Long-term continuous use and reduction of life cycle cost, by the technology of Japanese energy recovery system with the quality and durability.

Competitive advantage

1: Utilizing the DeROs® adjustable row rate, it is now possible to maintain continuous operation of water production while RO membrane cleaning is being performed, eliminating the need of costly downtime.
2: Freshwater produced can be controlled by modifying the speed of pistons.
3: Cost-benefit analysis:

For example, in the case of a plant with a desalination volume of 5,000 tons/day, the power consumption will be about 2.0 kWh per ton of desalinated water. In other words, at a power cost of 10 yen/kWh, the cost benefit would be 2.0kWh x 5,000ton/day x 365 days = 36.5 million yen/year.


    DeROs® can reduce about 50% of electricity consumption on high-pressure pump.
    Operational condition:
    ・Cylinder Size: diameter 350 mm×length 7000 mm or less
    ・Pressure range: 1.0-8.0 MPa
    ・Braine Capacity:100-9,000 m3/day
    ・Efficiency rate: 98% or more
    ・Mixing rate: Less than 1%
    ・Over-flash rate: Less than 1%
    ・Noise Level: Less than 75dB (A)

    Technical maturity / Past record of introduction

    Salt production/Japan
    Desalination/Kingdom of Saudi Arabia

    Information on patent related to this technology


    Company Data

    Company data

    Address 1-5-1, Omori-kita, Ota, Tokyo, 143-8558, Japan
    Capital 810 million JPY (as of 28 January 2022)
    Contact person

    Mr. Nagasawa  +81-3298-5121 (Japan)
    Mr. Suzuki  +65-9062-7595 (Singapore)
    Mr. Sato  +971-509001766 (U.A.E.)
    Corporate website:

    Number of employees 573 (as of 28 January 2022)
    Date of company foundation September 1910
    Type of business

    1: Manufacture and sale of fluid machinery
    2: Manufacture and sale of wastewater treatment equipment and waste processing equipment
    3: Manufacture and sale of switchboards and electrical instrumentation control devices and telecommunications control devices
    4: Manufacture and sale of energy recovery devices for seawater desalination
    5: Planning, designing, supervision and installation for the equipment related to each of the preceding items
    6: Manufacture and sale of equipment related to dredging as well as dredging work
    7: Leasing and management of real estate
    Investment and financial services to other businesses that DMW supports as required
    8: Business related to each of the preceding items

    International operation

    Number of employees for international operation 
    Overseas offices

    City, Country Name of Company (if applicable)

    Dubai, U.A.E.

    Middle East Branch


    South-East Asia Branch

    Mumbai, India

    DMW Corporation India Private Limited

    Modality of business transaction

    1: Sell the finished products to the EPCs, for OEM.
    2: Sell the finished products to the local distributor as a partner, for aftermarket.

    Export of product
    Using our overseas Branches with sufficient communication with our partners, we ship the finished products from Japan.

    Contact Person(s)

    Mr. Nagasawa (Japan)E-mail:
    Mr. Suzuki (Singapore)E-mail:
    Mr. Sato (U.A.E.)E-mail:

    *Please mention that you saw UNIDO's website when making the first contact with the company.

    Registered Category

    • Energy Technologies : Energy saving and energy storage