Scrubbers FAQ – Everything you need to know about scrubbers
How marine scrubbers work
A scrubber is a marine exhaust gas cleaning system that removes sulphur oxides (SOx) and other pollutants from a ship’s engine or boiler exhaust.
In practice, it allows a vessel to keep burning high-sulphur fuel oil (HSFO) while bringing actual emissions down to the limits defined by IMO and local regulations. Systems like ME Productions ClearSmart EGCS are designed and sized to meet or exceed SOx removal efficiencies of more than 98%, across system diameters roughly from Ø1300 to Ø6500 mm.
How do marine scrubbers work?
If you’re asking “how do marine scrubbers work?”, the principle is simple:
- Exhaust gas is routed into the scrubber tower from main engines and/or boilers.
- Spray nozzles inject wash water (seawater or fresh water with alkaline additive, depending on system type).
- SOx and particulates are absorbed into the water through physical and chemical interaction.
- Cleaned exhaust leaves the funnel, with sulphur content equivalent to compliant low-sulphur fuel.
- Wash water is treated, monitored, and discharged or recirculated, according to open loop, closed loop, or hybrid design.
The technology is well proven. The difference between suppliers is engineering quality, system layout, and how well the solution fits the vessel and its operating profile.
What types of marine scrubbers exist?
Most marine scrubbers fall into three main categories:
- Open loop scrubbers
Use seawater’s natural alkalinity. The treated wash water is discharged overboard within MARPOL limits.
- Closed loop scrubbers
Use recirculated fresh water plus alkaline additive. Sludge and residues are retained on board for disposal ashore. Suitable where discharge is restricted.
- Hybrid scrubbers
Can run in both open and closed loop. This gives flexibility when trading between open ocean and ports or areas with discharge bans.
ClearSmart EGCS is available in all three configurations, including conversion solutions to closed loop for any other scrubber make.
Why install a scrubber instead of just burning low-sulphur fuel?
A scrubber is primarily an economic and strategic tool:
- Fuel flexibility – keep access to HSFO where the spread versus VLSFO or MGO makes sense.
- Compliance security – emissions are cleaned mechanically, independent of fuel blending quality.
- Payback potential – depending on fuel spread, consumption, and remaining vessel lifetime, many projects have a payback measured in a many cases less than, or around, 1 year, not decades.
For high-consumption vessels – tankers, bulkers, container ships, RoRo ferries – the OPEX upside is often significant when the system is engineered and maintained properly, however there is a trend with the increasing 0,1 % sulfur caps being implemented more widely, that ships with lower fuel oil consumption, or age, tend to move towards a scrubber solution.
Overall deep sea trading vessels or vessels trading within international waters tend to choose scrubber solutions for a cost effective operation, that can give a competition advantage.
Are scrubbers still allowed and future-relevant?
Yes. Scrubbers remain fully accepted under IMO MARPOL Annex VI as a recognized equivalent method to meet sulphur emission limits.
What is changing is the landscape for wash-water discharge. More ports and coastal states are restricting or banning open loop discharges in their waters, but the future energy mix is also accommodating scrubbers as HFO is cheap and easy available.
The technical answer is:
- Choose hybrid or hybrid-ready designs for new projects.
- Consider open-loop-to-hybrid conversions if your fleet is exposed to a growing number of discharge restrictions.
- Choose scrubbers if you want flexibility in your vessel route planning and be ready to utilize cheap and highly available fuel oil.
ME Production designs ClearSmart EGCS with modular layouts that can be prepared for hybrid operation and integrated with future upgrades, including more advanced water treatment and potential carbon-reduction add-ons.
What does a scrubber retrofit involve?
A scrubber retrofit does not have to be a nightmare project. The key is a structured process and modular design.
ME Production’s retrofit approach typically follows a five‑step EGCS retrofit model:
- Feasibility assessment – vessel layout, engine data, trade patterns, and class requirements.
- Custom engineering – system design tailored to space, stability, and operational constraints.
- Modular construction – skid-based units pre-assembled and factory-tested before shipment.
- Installation & commissioning – aligned with dry-dock to minimise off-hire.
- Training & support – crew training and handover to a long-term service framework.
This approach cuts risk, on-site fabrication, and time spent in the yard.
How long does a scrubber retrofit take?
There is no single number – it depends on vessel type, yard capacity, and scope (single engine vs multi-engine, hybrid systems, etc.).
As a rule of thumb:
- Engineering and planning run ahead of the docking window.
- On-yard installation is planned to fit into a scheduled dry-dock.
- Pre-assembled and pre-tested modules reduce onboard work and help keep the project inside the agreed docking period.
The objective is simple: align with existing docking cycles and avoid extended off-hire.
Can scrubbers be installed on newbuilds from day one?
Yes. For many owners and yards, integrating exhaust gas cleaning directly into the newbuild design is now standard practice and can future proof the ship.
ME Production delivers ClearSmart EGCS for newbuild tankers, RoRo ferries, and container ships, and many other ship types with systems engineered into the funnel and machinery concept from the outset. With a strong presence in China – where a large share of the world’s tonnage is built – ME Production supports shipyards locally with engineering, production, and project and commissioning execution. 
This reduces interface risk, keeps schedules predictable, and ensures the vessel is compliant from delivery.
What delivery models does ME Production offer for scrubber projects?
To match different yard setups and owner strategies, ME Production offers three main delivery models:
- Full project execution from design to commissioning.
- Single point of accountability – attractive when you want fewer subcontractors and clear responsibility.
2. Pre-assembled & pre-tested units
- Systems built and tested before shipment.
- Minimises installation time and technical risk on the yard – ideal for tight retrofit windows.
3. Bare bone scrubber solutions
- Core scrubber tower and key equipment supplied.
- Integration handled by the yard or owner’s own teams – relevant for strong in-house capability or CAPEX-driven projects.
What does scrubber maintenance and support look like?
A scrubber is part of the vessel’s environmental “front line”, so it needs structured care:
- Regular inspection of spray nozzles, pumps, and internals emission sensors
- Monitoring and calibration of pH, PAH, turbidity, and flow sensors
- Periodic cleaning and service on water treatment units
- Documentation and performance checks for class and authorities
ME Production’s Time-2-Service framework covers preventive inspections, proactive remote support, spare-part logistics, and crew training – backed by service hubs in Denmark, China, Singapore, and Panama.
How reliable are ME Production scrubber systems?
Reliability comes from two things: engineering heritage and execution discipline.
- ME Production has more than a decade of scrubber experience and hundreds of EGCS installations across vessel types.
- Engineering and production are handled in-house in Denmark and China for full quality control.
- The same precision mindset that underpins ME Production’s marine gear business – with 50+ years of Danish engineering heritage – is applied to scrubber design and manufacturing.
The result is a system built for continuous operation in harsh environments, not just for passing a one-off emission test.
How do I know if a scrubber makes sense for my fleet?
A scrubber is most interesting if your vessel:
- Burns a lot of fuel (deep-sea, high-load profiles).
- Has a meaningful remaining lifetime.
- Modernizing a fleet compared to alternative fuel conversion
- Trades in regions with consistent HSFO availability and a stable fuel spread.
- Faces port calls or routes where hybrid capability will protect flexibility.
A proper feasibility study should look at:
- Fuel consumption and expected HSFO/VLSFO/MGO spread
- Remaining lifetime and projected trading pattern
- Space, weight, and power margins
- Yard options and docking schedules
That analysis is usually the first step in any ClearSmart EGCS discussion.
Why ME Production for scrubbers?
If you’ve read this far, you’re not just searching “what is a scrubber?” - you’re evaluating who you can trust to deliver one.
ME Production brings together:
- Danish engineering heritage and precision manufacturing
- Proven ClearSmart EGCS technology in open, closed, and hybrid configurations
- Flexible delivery models for both retrofit and newbuilds
- A global service network that keeps systems compliant and available long after commissioning
The goal is straightforward: help shipowners move towards cleaner air while keeping fleets commercially competitive.
CONTACT OUR TEAM FOR ASSISTANCE
If you have any questions or need more details, feel free to contact us at info@meproduction.dk.