Oil Absorbent vs. Oil Solidifier

Oil Absorbent vs Oil Solidifier / Adsorbent

Last summer, the news coverage of the Deepwater Horizon accident in the Gulf of Mexico, as well as the Enbridge spill in Michigan, reminded the world that major oil spills still occur. Most people, though, do not think about the small drips and spills that can occur every day at the fuel dock or when boaters pump bilges into the water. To prevent the hidden costs associated with long-term exposure to hydrocarbons in the water, such as gel coat deterioration on boats, the deterioration of foam flotation on docks, and the cumulative effects on the fish and wildlife, marinas can use emergency cleaning products, such as an oil absorbent or solidifier, to clean the spill and prevent its spread.

When fuel or oil hits a surface, it instantly begins to spread or distribute itself. Gravity, surface tension, wind, waves, currents and viscosity affect this distribution or spreading. It is said that a teaspoon of fuel can spread sheen over a one-acre area. More importantly, those small drips and spills in the waterway can have a cumulative impact over time.

One teaspoon of fuel can spread oil sheen over a once-acre area, and the accumulation of small drips over time can have adverse effects on water quality.


Oil Absorbent vs. Oil Solidifier (a.k.a. Adsorbent)

Absorbents with polypropylene have been around for some time, helping in cleaning up fuel and oil spills, but they have limitations, such as sheen on the water surface, which can seep past a polypropylene pad or boom. Also, a polypropylene boom or pad can drip once it’s out of the water, especially if any pressure is applied to it. When dumped in a dumpster that is not watertight, absorbents can leak out on the ground, forcing marinas to clean up the original cleanup.

Solidifiers have technology that addresses these issues. This technology has been around for more than 20 years and received considerable attention last summer through involvement with the Deepwater Horizon and Enbridge oil spills.

Oil Absorbent vs Oil Solidifier / Adsorbent - C.I.Agent Bilge Daddy
As part of a bilge water management program, marinas can require boaters to use a bilge bag made from a solidifier / adsorbent, like this one from C.I.Agent Solutions, which will not leach any oil after it’s absorbed.

Unlike a polypropylene absorbent that acts like a sponge, a solidifier reacts with the hydrocarbon at a molecular level, encapsulating the fuel or oil and turning it into a rubber-like substance; it is easy to clean up and will never leak or leach. Solidifiers are hydrophobic, meaning they do not attract or absorb water, and will always float. With no water absorption, the overall mass and waste material increases less. Because a solidifier / adsorbent will always float, it is much easier to effectively and efficiently control and remove a spill with less time and labor.

Generally, in a contained application form (booms, pillows or socks), absorbents and solidifiers will act similarly, and in loose form, both could have some containment and recovery issues. Both require visual monitoring to determine when each product can be removed and relatively the same amount of time to pick up oil.

The chart below provides a general comparison of the differences between absorbents and solidifiers.

How product works A physical reaction turns the oil into a floating, rubber-like mass Like a sponge, absorbents take in the oil as well as water
After use Will not leach even when squeezed Will drip, drop and leach out oil
Effectiveness with light oils Very effective Can recover but will leak out of absorbent material
Effectiveness on sheens Can remove even light sheens Cannot pick up sheen
Effectiveness with heavy, viscous oils Effective with all types of oil, based on formula variations Dependent on type of oil
Temperature No effect No effect
Flash point Lowers flammability of treated oil May lower flammability
Volatile fumes Can reduce volatile fumes, depending on product No effect on fumes
Worker training Training helps solidifiers work more effectively with less waste No training required, but an oil absorbent is often overused due to lack of training
Application on solid surfaces Effective on solid surfaces, where solidified oil can be swept up Not as effective as solidifiers
Waste volume Proportional to amount of solidifier used, very little volume increase Large waste volumes
Waste weight Equal to the weight of solidifier Equal to the weight of the oil absorbent plus water it picks up
Waste disposal-landfill Solidifiers can be disposed of in most landfills since the pass leach tests An oil absorbent should be disposed of as a hazardous waste; leaching is a concern
Waste disposal-incineration High BTU value and low ash Low BTU
Recycling of used product Can be recycled into other industrial processes including asphalt modification, rubber additive, or burned as fuel Not applicable for most traditional absorbents

Additional information on the application of an oil absorbent and solidifier, prepared by the National Response Team Science & Technology Committee, which coordinates response planning at the federal level, can be found on the EPA website at http://www.epa.gov/osweroe1/docs/oil/ncp/SorbSolidifierFactsheet2007finalV6.pdf.

Solidifiers and absorbents do vary on cost, but marinas should consider both the upfront cost and the long-term cost with continued use of each product. Solidifiers are more expensive than absorbents on a per pound basis. However, that upfront cost for solidifiers may be extended in the long run, compared to absorbents. Numerous case studies have documented the clean up of hydrocarbon spills with each, and considering the effectiveness and efficiency of what they each accomplish, solidifiers make an excellent case for cost effectiveness. Also, solidifiers can be discarded in a landfill. While an oil absorbent is more inexpensive to purchase upfront, large quantities are usually needed, which can be costly to dispose.


SPCC Guidelines

Marinas that have bulk storage tanks should be well aware of the Spill Prevention, Control and Countermeasure (SPCC) Guidelines, which regulate secondary containment to prevent any hydrocarbon leaks from entering navigable waterways. Marinas that need secondary containment around storage tanks can use solidifier technology to save them at least 50 percent when compared to a poured concrete solution.

Even marinas without large fuel storage tanks should have emergency response plans for spills. It is important to act with urgency to contain even small spills, as a small amount of oil can affect a large area with a hydrocarbon sheen. Like the polypropylene absorbents generally in use today, solidifier technology offers booms, pillows and pads. One person, for example, can use a quick deployment boom to encircle a spill, contain it and prevent its spread over a larger area. With a solidifier, it can also be dragged over a light sheen to clean it up. Unlike the polypropylene boom that is discarded after each use, booms made from a solidifier can be cleaned and reused until the solidifier has reached full saturation.


Bilge Water Management

Marinas can also incorporate solidifier technology into bilge water management plans. Unlike the polypropylene products used to manage fuel or oil in bilge water, a bilge bag made from a solidifier will not leak or leach. A poly pad pulled from a bilge will drip and leak, leaving boat owners to dispose of it quickly so as not to leave a mess in the boat. Most likely they throw that pad into a nearby trash can, which may have cracks that leak the fuel/oil out onto the ground or dock. In rain or splashing water, the fuel/oil goes back into the marina water. Plus, hydrocarbon contaminated polypropylene is to be disposed of as a hazardous waste.

A bilge bag made from a solidifier could be wrung out by hand without seeing any fuel or oil leach out. Also, disposing of the used solidifier bilge bag requires no special container; just toss it in with normal trash.

Many marinas take pride in the fact that they have a Clean Marina designation, and solidifier technology can improve and enhance that effort. As part of a Clean Marina plan, marinas can incorporate solidifier bilge bags into maintenance programs and rental agreements. Each spring as maintenance crews prepare boats for the new season, place a bilge bag using solidifier technology in the bilge. Likewise, require boaters with rental agreements to use a new bilge bag at the beginning of the season. Some manufacturers offer marina owners small window stickers to show a boat’s bilge is protected.



The sad truth is that most boat owners are not likely to adopt a bilge water management program on their own. Many marinas now charge an environmental fee and incorporate the cost of a solidifier bilge bag into that fee. A point-of-purchase counter display can draw customer attention to available solidifier products, and staff can educate customers about how they benefit the environment. These programs, along with a dockside oil spill response kit, will show that marinas are serious about protecting the water with the help of solidifier technology.

As part of a Clean Marina plan, marinas can incorporate solidifier bilge bags into maintenance programs and rental agreements.

Marina operators rely on the water to support their living, so they should make every effort to support and educate their boaters on keeping the waterways clean for generations to come. The average boat owner has seen sheen on water as long as they have been a boater. They likely do not know about the Clean Water Act nor the regulations and fines associated with it. It is crucial that marinas take the leadership role to educate and protect their customers and themselves from fines, as well as do all they can to protect the environment.

View the original magazine article PDF

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