How MPak® Coalescing Plate Technology is Revolutionizing Oil-Water Separation

In 2024 alone, the EPA issued a staggering $1.7 billion in fines for water quality violations—doubling the previous year’s total. Numbers like these should put every facility manager on alert.

Under the Clean Water Act (CWA), industries from manufacturing to marine are held to strict limits on how much oil and other contaminants can be present in wastewater discharged to the environment. And those limits are only getting tighter each year.

Here’s the challenge: traditional oil-water separators—once the industry’s go-to solution—often fall short. They’re slow, struggle with heavy solids, and don’t scale easily as your needs grow. So, what’s the answer?

Enter coalescing plate separators. These innovative systems are helping companies meet today’s demanding regulations, lower long-term costs, and simplify their wastewater management. In this article, we’ll cover:

• Which industries depend on oil-water separation technology
• The biggest hurdles in achieving compliance
• How coalescing plate separators work and why they matter
• What makes the MPak^® system the new standard for efficient, reliable oil-water separation

Oil-water separation is essential for any operation that produces wastewater or runoff contaminated with oil or hydrocarbons. Below are some of the key sectors that rely on this technology to maintain compliance, protect assets, and improve environmental sustainability.

In short, any industry that generates oily wastewater or runoff needs an effective solution to handle oil-water separation. This includes the following and more:

• Storm Water Runoff
• Airport Tank Farms
• Marine Vessels and Rigs
• Industrial and Manufacturing
• Oil Refineries and Storage Terminals
• Offshore Platforms and Wind Farms
• Onshore and Offshore Oil and Gas Production
• Floating Infrastructure

So now we know who needs oil-water separation, but what’s the big deal? Why is modern oil-water separation a challenge, and why do the traditional methods fall short?

No matter the industry or application, effectively separating oil from water isn’t as simple as it may sound. Many facilities face a range of persistent challenges that can threaten compliance, increase costs, and disrupt operations if not properly managed.

So, how do modern coalescing plate separators step up to address these challenges? Let’s explore how this technology works and see how the latest advancements are raising the bar for oil-water separation across modern industries.

Before we dive into the process, we need to examine the anatomy of typical oil-water separators and how coalescing plates fit into the system.

Most industrial oil-water separators share a similar layout, generally organized into three main chambers:

• Influent Chamber: The entry zone where raw contaminated water enters the separator.
• Separation Chamber: The core chamber where the actual removal of oil from water takes place.
• Effluent Chamber: The final chamber where treated water collects and exits the separator.

Coalescing plate packs are the centerpiece of the separation chamber. These modular bundles contain an array of tightly packed, corrugated plates.

Coalescing plate separators (or “corrugated plate interceptors”) are oil-water separators that employ the use of coalescing plates to augment the separation process.

Conventional gravity separation can be slow and space-consuming, but the introduction of coalescing plates transforms this process by making it faster and much more efficient. These plates leverage the physics of Stoke’s Law, where larger oil droplets rise more rapidly through water than smaller ones.

By encouraging the rapid merging (coalescence) of small oil droplets into larger globules, coalescing plate separators accelerate the natural separation, boosting efficiency while significantly reducing the system’s physical footprint.

Now that we’ve covered what coalescing plate separators are, let’s closely examine the separation process.

Before startup, the separator tank is filled with clean water to create a baseline water level. Once the baseline has been established, the separation process is ready to begin.

First, the contaminated water—containing a mixture of oil droplets and suspended solids—enters the separator from the inlet pipe and fills the influent chamber.

Next, the oily water is directed through the tightly packed corrugated plates. This is where the wonder of coalescing plate technology truly shines.

As the mixture passes over and between the plates, two critical processes take place in a single stage.

Oil droplets within the water—being lighter and less dense—naturally rise to the underside of the plates. As they collide on the surfaces of the plates, these tiny droplets stick and coalesce, joining to become larger globules.

This matters because the larger an oil droplet is, the faster it rises. Additionally, the structure of the plates also shortens the oil droplets’ path to the surface. This dramatically accelerates the oil separation process.

The oil globules move upward along the inclined plate surfaces, migrating from plate to plate through the weep holes until they reach the water’s surface. There, the separated oil accumulates as a distinct layer, ready for removal.

At the same time, suspended solids within the water are pulled by gravity onto the topsides of the plates. The solids slide down the inclined plate surfaces and fall through the drain holes, moving from one plate to the next until finally settling at the bottom of the tank.

After completing its journey through the labyrinth of coalescing plates, the treated water collects in the effluent chamber.

Finally, the clean effluent flows out of the separator through the outlet pipe, meeting the necessary standards for oil content and clarity.

1. The entire system is filled with clean water prior to startup.
2. Dirty/oily water enters the influent chamber via the inlet pipe.
3. The contaminated water passes through the coalescing plates where oil rises to the surface and solids sink to the bottom.
4. Clean water flows into the effluent chamber and exits the separator via the outlet pipe.

While all coalescing plate separators share the same basic principles, not all designs are created equal. Let’s investigate what makes the MPak coalescing plates stand out as the optimal solution for oil-water separation.

Facet’s MPak Coalescing Plates are engineered for demanding oil-water separation, combining high performance, adaptability, and unmatched serviceability.

The MPak plates address the key challenges in oil-water separation by providing the following benefits:

MPak plates are constructed from a highly oleophilic material and feature bi-directional corrugation. This design maximizes the surface area available for oil droplet coalescence and shortens the path the droplets must take to reach the surface, all while reducing the overall system footprint.

Unlike many other coalescing plate technologies, the MPak doesn’t take a one-size-fits-all approach. With multiple plate spacing options and a modular support system, MPak packages can be easily installed in both new and existing oil-water separation units.

The MPak can be fully customized to match the needs of any site, flow rate, or operating condition.

Engineered for single-stage operation, the MPak reliably reduces oil contamination to as low as 5 ppm while also efficiently handling solids. This helps operators meet today’s strictest discharge standards without complex, multi-stage setups.

Unlike most conventional plate systems, the MPak is designed for simple cleaning, so no full-system teardown is required. In addition to this, Facet offers the exclusive MPak Cleaning Wand to clear accumulations directly in place, drastically reducing the maintenance effort and keeping your operations running smoothly.

With a 30-year life expectancy (with regular preventive maintenance) and no consumable parts, the MPak plates are made for the long haul. Fewer changeouts and replacements and longer service life leads to a dramatically lower cost of ownership compared to other technologies.

With water quality regulations tightening and operational demands rising, the way we approach oil-water separation needs a serious upgrade.

Facet’s MPak coalescing plate separator system steps up to meet that challenge, offering facility teams a smarter, more reliable way to stay compliant, without the headaches that come with older separator designs.

What makes the MPak stand out? It’s the combination of efficient oil removal, modular design for both new and retrofit applications, and hassle-free cleaning that keeps things simple.

No more lost sleep over system fouling, costly downtime, or ever-growing lists of consumables. The MPak handles tough inflows and strict discharge limits in a compact, easy-to-maintain package.

This goes way beyond ticking regulatory boxes. Investing in a next-generation separator means fewer worries about the future, less time spent on maintenance, and more time focused on your real priorities.