The Absorbent Solutions

The interesting thing about cleaning up the spills identified above is how many choices are available in the marketplace to address the mess. Waste companies use a variety of liquids such as hydraulic oils, engine oils, lubricants, solvents, acids, coolants and fuels that are in regular-use events at every facility. When these are spilled on the shop floor or out in the field, there are many clean-up solutions.


Crushed Clay (aka “Cat Litter”)

This is probably the most well-known product used primarily for oil and grease clean-up. It is packaged and sold by numerous manufacturers and brands. It has been around for more than 50 years and is an older technology that’s been used by generations of mechanics. Despite its widespread popularity, crushed clay is also well known as a very dusty product that doesn’t really absorb well. That dust content is the part of the product that has any effectiveness, but it’s also the same silica dust that causes respiratory health risks to workers. The product is very inexpensive, which is the main attraction in using it. However, facilities that use crushed clay will end up paying high disposal costs to remove the waste material. In connection with the high disposal fees, most users have to use excessive amounts of the product to accomplish any drying of spilled liquids. The total cost associated with using crushed clay in a waste facility is a higher cost-per-use than most purchasing managers realize.


Sorbent Pads (aka “Diapers”)

Another popular choice by many shops, these pads come in different shapes, sizes and can also be limited to working with certain liquids. Most pads are made of polypropylene material, which is a petroleum-based product. Pads are supplied by numerous distributors and dealers. The initial purchasing mindset of shop managers has been that pads are more attractive on the floor in terms of a clean, white square. However, most users quickly realize when they pick up the pad from the floor that residue or slickness was left behind under the pad. Used pads are difficult to handle or carry while dripping, and typically a second pad or follow-up cleaning with a rag, degreaser or mop treatment is required. This difficulty makes the use of pads require more time in clean-up. Pads also do not perform well in open shop environments that are drafty as they will often blow away. The disposal of these pads brings up some environmental concerns and requires special waste handling, increasing the costs of shop operation. The consensus is that pads are a high cost-per-use product that requires special waste disposal.


Alumina Silicate

This material typically falls into the category of a zeolite or perlite. It is usually mined from volcanic ash and processed with extreme heat. As an absorbent, it is generally a white color and has a very fine, granular consistency. This product is very lightweight and can be dusty, which can lead to eye or respiratory irritation. Some manufacturers have taken steps to reduce the dustiness by adding suppressants. However, this type of material is known to absorb humidity over time, so it may gradually lose its effectiveness as an absorbent. The product’s performance advantages are balanced against its dustiness and lightweight properties to limit its widespread adoption in waste environments.


Diatomaceous Earth (DE Powder)

Another product comprised of naturally or artificially calcined remains of microscopic water plants. It’s a mined product and starts out as hydrous silica formations and, when processed, becomes a fine, light-colored powder. It has a very high porosity formed by a vast number of air cavities previously occupied by billions of diatoms per cubic inch, making it very lightweight and absorbent. The commercial form of this product can be very dusty, similar to silicate products and not a good performer outside or in shops with air circulation.


Plant By-Products

These are a relatively new, biobased alternative to crushed clay and pads. These are derived from corn cob grindings, cellulose paper-based material, plant seed grindings, peat moss (Sphag) and even wood shavings. These products are typically selected for use with oil clean-up and once soaked with oil can be burned to generate energy. However, most users experience the need for follow-up cleaning or at least a second application of the product to complete the absorption job due to residue or slickness left behind after the first application. Despite the product having some performance advantages, the dustiness and lightweight properties seem to limit these various forms of biobased products into widespread adoption by waste facilities.



A new absorbent technology developed from specialized soils with specific pH balance and ionic attractions to the chemicals in spilled liquids. This material is bio-based and possesses a large surface area and porosity, allowing it to perform well on a variety of spilled liquids. It is a very stable and low-dust material with the ability to encapsulate and bind with spilled liquids, potentially making the waste disposal much simpler. Because of its performance characteristics and less product needing to be used to absorb a spill, the volume of waste created is reduced along with accompanying labor costs. While this material has a higher cost per pound, analysis shows the use of the material can be more economical and have a lower cost-per-use for waste applications.

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