For industries: Marine Offshore Building This section is only for development help

Evac MBR Membrane bioreactor, biological wastewater treatment systems

The Evac MBR  (membrane bioreactor) is an advanced wastewater treatment process that can treat all wastewater streams to current standards. Evac MBR treatment plants are certified to meet the IMO MEPC 227(64) with nutrient removal, and also have River Rhine certification and U.S. Coast Guard (USCG) type approval.

The Evac MBR is a biological sewage treatment plant that offers advanced black and gray wastewater treatment solutions. It directly replaces traditional biological units, and with its membrane technology it easily fulfills all current and imminent treatment requirements. In some cases, effluent from the unit can even be recycled for specific uses. It allows vessels to operate in environmentally sensitive areas, treating and discharging all wastewater generated by passengers and crew without threat to health or the environment. It is based on proven, very low-maintenance membrane bioreactor technology, which is capable of filtering out particles, even those as small as bacteria.

The compact footprint of the membrane bioreactor makes it ideal for retrofit to existing vessels, as well as for installation on new ships.


  • Proven technology with very low sludge production
  • Extremely low running costs and minimal energy consumption
  • Membrane has an expected lifetime of over 10 years and is resistant to clogging and fouling
  • Compact footprint
  • No continual chemical consumption
  • Disinfection and dilution water are not required

  • Available also with combined vacuum creation for toilet system
  • Fully automated and easy to operate with MLSS- and pH-sensors
  • Easily customized for your preference
  • Option to connect directly to inlet line (no holding tank needed)
  • Nutrient removal available as an option
  • Over 500 marine references

Operating principle of the Evac MBR, membrane bioreactor

All Evac MBR plants work in the same way, using proven, very low maintenance membrane bioreactor technology that is capable of filtering out particles as small as bacteria.

The treatment process consists of three phases:

  • Pre-treatment
  • The biological process
  • Membrane filtration

Clean water is separated from the biomass using membrane filtration with submerged flat-sheet membranes. The pressure difference for the membrane filtration is only around 30 mbar – such a small amount of pressure guarantees the membranes an extremely long life. The treated water does not need any further disinfection and can be discharged directly into the sea.

The Evac MBR does not require any back-flushing or constant chemical cleaning, making it the most economical and maintenance-friendly membrane solution available today. The effluent quality is so good that it can be reused.

Standardized mid-range

All mid-range standard Evac MBRs are available in two models: a basic version and a combined unit known as the C-model.

In combined units the Evac MBR is equipped with an ejector vacuum unit, so no separate ejector vacuum unit or collecting tank is required. A combined Evac MBR unit has several advantages: although the C-model has a slightly larger footprint than its basic counterpart, the total footprint of the MBR unit and the ejector vacuum unit is smaller than the footprint of two separate units. The C-model is also easier to use as both units can be monitored from a single control panel. C-models are also more cost-effective than purchasing a basic model and an ejector vacuum unit separately.

For mid-range Evac MBRs, a nutrient removal (N) module is also available if required.

Large and customizable

Custom-designed Evac MBRs are typically used when the hydraulic or organic load requirement of the application is so high that the use of Evac standard units is not possible.

Because of the large size of cruise vessels, custom-designed membrane bioreactor plants are the only option for all but the smallest river cruise vessels. The capacity of custom-designed membrane bioreactors, including their hydraulic and BOD loads, can be agreed separately with Evac.

A custom-designed MBR plant can also be used for applications with special requirements, such as nitrogen or phosphorus removal. For all large and custom-designed Evac MBRs, a nutrient removal (N) module is also available if required.

SizeModelMax hydraulic loading (m³/day)Organic loading (kg BOD₅/day)Dry weight (kg ± 10%)Wet weight (kg ± 10)Dimensions L x W x H (mm)
Mid-range MBR (C) (N)Evac MBR 7K7.54242777351865 x 3130 x 2200
Evac MBR 15K1583850126502000 x 4225 x 2200
Evac MBR 22K22114375154262115 x 4490 x 2200
Evac MBR 30K3015560022002860 x 4255 x 2200
Evac MBR 45K45236649286602980 x 5555 x 2200
Large MBR (N)Evac MBR 70K70354985181804390 x 2289 x 2200
Evac MBR 95K95506397248165690 x 2469 x 2200
Evac MBR 120K1206074183133165890 x 2890 x 2200
Evac MBR 145K145758472372866898 x 2969 x 2200
Evac MBR CustomCustom only
Also available with vacuum creation (C) equipment and nutrient removal (N) as an option. Customized units for vessels with limited available space are also available.
Note: Large MBR units do not include an equalization tank. Evac reserves the right to make modifications.



  • Evac MBR wastewater treatment leaflet
    Type: Leaflet Language: English Industry: Marine, Offshore, Building
  • Getting Retrofits Right
    Type: Article Language: English Industry: Marine, Offshore
  • River certificates issued Evac MBR 7K - 70K product range
    Type: Article Language: English Industry: Marine, Offshore, Building