Absorbents for spill containment

Responding is Eric J. Minder, P.E., vice president of environmental operations, Closed Loop Recycling, St. Louis.

Absorbents work by using capillary action, where released liquids are drawn into the absorbent material spaces or pores through surface tension, effectively “soaking up” the liquid; the liquid is retained with the structure of the absorbent matrix. For organizations that use absorbents for spill containment purposes, the transport of the released liquids is controlled, and the release is converted into a more manageable solid mass. Absorbent materials used for spill response come in several different formats, but most typically are purchased in the form of textiles (examples: socks, rags, mats, towels, berms) and powders/granules (clay, polymers).

Aside from the determination of the appropriate format, additional considerations include the rate of absorption (lower-density products typically absorb faster than those of high viscosity and density), product retention (lighter, lower-density products are more easily lost through the pores than the heavier more viscous products) and ease of application (powdered/granular absorbents are easy to apply and maneuver, but can be easily lost if applied in windy conditions).

Users should also be aware of the industrial hygiene implications of fibrous and granular absorbents, and the use of powdered/granular absorbents within or in the vicinity of high-precision machining and manufacturing assembly environments because of air quality considerations.

In preparation of a spill or release situation, the user of absorbents for spill containment will need to come up with a reasonable estimate of the amount of absorbent to keep on hand for containment and remediation actions. As previously noted, knowing the absorption rate and product retention characteristics of the absorbents will allow the user to better assess the amount(s) necessary, while an understanding of how a release will spread is an important factor in determining the location of absorbent stores.

Finally, of particular consideration for the users of absorbents for spill containment is the determination of the appropriate disposition or alternative for the cleanup material (in other words, absorbent plus absorbed chemical[s]). The user will need to determine, either through product knowledge or laboratory analysis, whether the cleanup materials meet the definition of a regulated material. If so, jurisdictional regulation may specify the disposition method. (For example, landfill disposal in a special waste or hazardous waste landfill, or hazardous waste incineration).

For those cleanup materials that aren’t regulated or minimally regulated (for example, those determined to be nonhazardous or nonindustrial wastes), more disposal options and more sustainable alternatives to disposal (for example, launderable rags/towels/wipers) are commercially available.

Editor's note: This article represents the independent views of the author and should not be considered a National Safety Council endorsement.