Marine Pollution Prevention Equipment: A Register Snapshot

Bilge water separators, oil-content meters, oil-filtering equipment, sewage systems and shipboard incinerators are grouped under one broad label in type-approval registers: marine pollution prevention. Together they cover the systems a ship carries to keep oily bilge water, sewage and solid waste from going overboard or up the funnel in a form that breaches MARPOL limits.

This piece works from three of our own data sets: our type-approval register, filtered to the DNV product types that fall under this umbrella; our equipment library, which holds datasheet-verified models for one specific product group inside that umbrella, oily water separators; and our supplier directory, filtered to firms whose profile mentions oily water, bilge, sewage or separator work. None of the three is the whole market. Each is a slice of it, and the slices do not always line up neatly with each other.

The intended reader is technical staff at a shipowner, a buyer in a procurement department, a yard engineer specifying equipment for a newbuild or retrofit, or a service company deciding which manufacturers to carry spares and expertise for. Data stand: September 2026.

What our register covers for this equipment group

Filtered to the relevant DNV product types, our type-approval register lists 918 products from 55 manufacturers. Most of these certificates fall under the Marine Equipment Directive, which accounts for 868 of the 918 products. A further 33 sit under a plain Type Approval group, and the remaining 17 fall under the Marine Equipment Regulation, the framework that runs alongside the Directive in our data.

That split matters for a buyer: a Marine Equipment Directive wheelmark and a Marine Equipment Regulation wheelmark are not automatically interchangeable paperwork, and a plain Type Approval certificate from a classification society is a different document again from either. When a product family shows up under more than one of these groups in our register, treat that as separate certification records to check, not one.

Product types in the register

The 918 products split across a long list of specific DNV product types, several of which are near-duplicates of each other, differing only in punctuation or a missing word in the source label. The largest and most consistently populated types are:

• Marine pollution prevention (Marine Equipment Directive) - 777 products from 16 manufacturers, by far the largest single type in the register and the closest thing to a generic bucket for this equipment class.
• Shipboard incinerators, described in our register as incinerator plants with capacities up to 4,000 kW (Marine Equipment Directive) - 22 products from 7 manufacturers.
• 5 ppm Bilge Water Separator (Type Approval) - 19 products from 16 manufacturers, meaning most manufacturers under this type have only one or two approved products.
• Sewage systems for ships other than passenger ships, in all areas, and for passenger ships outside MARPOL Annex IV special areas (Marine Equipment Directive) - 18 products from 11 manufacturers.
• Oil-content meters (Marine Equipment Directive) - 16 products from 9 manufacturers.
• Oil-filtering equipment for an oil content of the effluent not exceeding 15 p.p.m. (Marine Equipment Directive) - 13 products from 9 manufacturers, with an 11-product, 8-manufacturer entry carrying an almost identical label in the same group.
• Sewage Treatment Plants (Type Approval) - 9 products from 5 manufacturers.
• Sewage systems for passenger ships in all areas, including a MARPOL Annex IV special area (Marine Equipment Directive) - 9 products from 8 manufacturers.

Below that, a handful of smaller entries repeat the same product families under the Marine Equipment Regulation rather than the Directive, or under labels that differ from the ones above by a comma or a closing bracket: an 8-product, 5-manufacturer sewage-systems entry, a 5-product, 3-manufacturer Sludge and Waste Incinerator entry, and several entries down at 1 to 3 products each. Read these as fragments of the same handful of product families rather than as separate equipment categories.

Who holds the approvals

Approval-holding in our register is concentrated at the top. MAHLE NFV GmbH alone holds 518 products, and its related company Mahle Industriefiltration GmbH holds a further 173, so these two entities together account for well over half of the 918 products in the register. Dongtai City follows a long way back with 45 products, then JOWA AB with 13, DESARROLLO TECNICAS INDUSTRIALES DE GALICIA, S.A with 11, Evac Oy with 9, and a cluster of manufacturers - Wartsila Water Systems Ltd., Atlas Incinerators ApS, TeamTec AS, TECNICOMAR S.p.A. and Volcano Co., Ltd. - each holding 8. Alfa Laval Technologies AB holds 6.

By country, Germany leads with 11 manufacturers in this list, ahead of China with 8, then Sweden and Japan with 5 each, the United Kingdom of Great Britain and Northern Ireland and the Republic of Korea with 4 each, Norway with 3, and Greece, Finland and Denmark with 2 each. Those ten countries cover most of the register's 55 manufacturers; the remaining manufacturers, a group of nine, are spread across countries outside this top list. This is a market with a long tail of manufacturers by headcount but a very short head by product count: two related German entities carry most of the volume, while the rest of the register is made up of manufacturers with a handful of approved products each.

Validity and expiry

Of the 918 products, 911 carry a valid certificate status in our register and 8 show as expired. That is a small share, but it is not zero, and a certificate that shows as expired in our data should never be assumed current without checking the manufacturer or class society directly.

Looking at nominal expiry years for the certificates in this group, the numbers cluster hard around one date: 741 of them carry a 2030 expiry. Smaller groups fall in 2026 (13), 2027 (17), 2028 (24), 2029 (23) and 2031 (13). A cluster of 82 entries carries nominal dates far in the future and should be treated with caution rather than taken at face value.

The practical takeaway for a buyer or superintendent is straightforward: never treat the presence of a certificate in a register as proof that it is still valid on the day a ship needs it. Request the current certificate from the manufacturer or class society, check its expiry against the delivery date or the next dry-dock window, and do not rely on an expiry year alone without seeing the document itself.

What the equipment library adds

For one product family inside this pollution-prevention group, oily water separators, our equipment library goes a layer deeper than the type-approval register. It covers bilge water treatment for MARPOL Annex I compliance, spanning what the library labels 15 ppm OWS and Oily Water Separator (15 ppm) equipment types. Total model counts in this category are not verified and are not quoted here; what is verified is that 53 models carry a checked datasheet, and of those, 10 have checked key figures beyond the datasheet itself.

Among the manufacturers with datasheet-backed models, MAHLE NFV has 9 such models, illustrated by the MPEB-1. RWO Water Technologies has 7, shown by the OWS-COM. SKF also has 7, with the Turbulo-MPB TMPB 0.25. Jowa has 5 datasheet-backed models, represented by the 3Sep OWS-0.5, and Taiko Kikai Industries has 3, shown by the USH-01. Alfa Laval, Victor Marine and Marinfloc each have 2 datasheet-backed models, with the PureBilge 2515, the CS2000 and the CD Unit as their respective examples.

Cross-checking these library manufacturers against the type-approval register shows how uneven coverage can be even for well-known names. MAHLE NFV's 518 register products sit under a single register entry, Alfa Laval's 203 register products are spread across 13 entries, Jowa holds 19 products under one entry, Victor Marine 13 products across 3 entries, Marinfloc 12 products under one entry, and Taiko Kikai Industries just 1 product under 1 entry. A manufacturer with a strong datasheet presence in the library is not automatically the one with the broadest type-approval footprint, and the two data sets are best read side by side rather than one standing in for the other.

The library also records typical failure modes for this equipment: feed-pump seal wear or suction-side air ingress causing unstable flow or poor separation, pump wear or air ingress reducing throughput, oil-content-meter calibration drift, coalescer element saturation or clogging, activated carbon exhaustion, and solenoid valve failure. Service notes attached to specific manufacturers point in the same direction: clean the oil-content-meter sensor weekly and plan on membrane replacement every 12 to 18 months for MARPOL Annex I compliant units under close port state inspection focus; replace coalescer and carbon elements on RWO-type units per the maintenance schedule; calibrate oil-content meters monthly on simpler designs and replace coalescer elements annually; size filter-element replacement to differential pressure and calibrate oil-content meters yearly on multi-stage units; and, for electrocoagulation designs with no consumable filter elements, replace electrodes on an operating-hours basis rather than a calendar one.

These failure and service patterns line up with the vessel types the library associates with this equipment: offshore supply vessels, container ships, bulk carriers, general cargo vessels, fishing vessels and product tankers, in other words most of the merchant and offshore fleet rather than a narrow niche.

Where to find service and supply

Our supplier directory, filtered to firms whose profile mentions oily water, bilge, sewage or separator work, lists 206 firms. China leads with 32 of them, followed by Greece with 26, the United States with 19, Germany with 15, Italy with 14, India with 11, and Singapore and the Netherlands with 9 each.

A few examples from that list illustrate the range of what sits inside it. Olympus Marine Spares in Greece supplies OEM spare parts and exchange aggregates for rotary, screw and piston pumps. ABEL GmbH in Germany manufactures reciprocating positive displacement diaphragm pumps for marine bilge and related applications. Fujian Aidi Electric Co., Ltd., trading as SEAFLO, makes marine bilge pumps and DC boat pumps in China. Novel Valves India Pvt. Ltd. supplies overboard and ballast or bilge valves in duplex stainless steel from India. Between them these four firms span spare parts, pump manufacturing and valve supply, which is a reasonable cross-section of what a buyer looking for bilge or sewage-system support in this directory will run into.

How to use this when specifying or buying

• Confirm which certification framework applies to the vessel and route: Marine Equipment Directive, Marine Equipment Regulation and plain Type Approval are not the same document, and our register treats them as separate groups.
• Request the current certificate directly from the manufacturer or class society rather than relying on a register listing; 8 of the 918 products in our register already show as expired.
• Check the certificate's expiry date against the ship's delivery date or next dry-dock window, not just against the calendar year it falls in.
• Treat any nominal expiry date far in the future with caution rather than as a guarantee of long-term validity; a cluster of 82 entries in our register falls into that pattern.
• Where a manufacturer appears in both the type-approval register and the equipment library, check both records: the library adds failure-mode and service detail the register does not carry.
• For oily water separators specifically, budget for the consumables the library flags as recurring: coalescer and carbon elements, oil-content-meter calibration, and, on electrocoagulation designs, electrodes.
• Use the supplier directory to shortlist service and spares partners by country before contacting manufacturers directly, rather than assuming global coverage from a single agent.

Frequently asked questions

What counts as pollution prevention equipment in this data set?

In our register, it means any product whose DNV product type matches bilge water separators, oil-filtering equipment, oil-content meters, sewage systems or plants, or shipboard incinerators, whether certified under the Marine Equipment Directive, the Marine Equipment Regulation or a plain Type Approval.

Is Marine Equipment Directive certification the same as Marine Equipment Regulation certification?

No. Our register treats them as separate certificate groups, with 868 products under the Directive and 17 under the Regulation. A product certified under one is not automatically covered under the other, and both should be checked as distinct documents.

Why do some product types in the register look almost identical?

Several entries differ only by a missing bracket, a comma, or a slightly different word order in the source label, for example the two oil-filtering equipment entries at 13 and 11 products. These read as fragments of the same underlying product family rather than genuinely separate equipment types.

Does the equipment library cover total model counts for oily water separators?

No. The library explicitly notes that total model counts for this category are not to be quoted. Only the datasheet-verified figures, 53 models with a verified datasheet and 10 with verified key figures, are reliable enough to cite here.

This article is provided for general information and education. It does not replace professional advice.