Safety

what a barrel wants

By Lysa Holland

More in the Summer 2009 issue

Did you ever walk into the garage and find an old can of oil leaking all over the floor?  What a mess. If only you'd thought to keep it stored in that empty five-gallon bucket sitting right next to it!  
Well, that's all secondary containment is - a way to keep a leaking primary container from having its contents leak out to the floor, into a drain, or into the environment.  
Secondary containment is especially important for materials that have the potential to cause pollution.  
In a biodiesel operation this includes materials like methanol, used cooking oil, glycerin and finished biodiesel.  All of these materials have environmental consequences if they get into soil, surface water or streams, and ground water.  For home biodiesel facilities that are served by private wells, the possibility of preventing contamination to your water source is especially important.  
So when do you need secondary containment?  If the stored material could leak and the leak would get into the environment, then you should provide secondary containment.  
In Pennsylvania, secondary containment is required if the material is in a container with a capacity of 55-gallons or larger and a leak could get into the environment.  Other states may have similar requirements.  
For facilities that store 1,320 gallons or more of oil above ground, secondary containment is an EPA requirement under the Spill Prevention, Control, and Countermeasures (SPCC) Plans regulations.  But besides being a requirement, it's a good idea.  
Secondary containment can range from purchased items that were specifically designed for this task to any container that you might already have, such as a plastic five-gallon bucket.  
The containment must be made of a material that will not react with any of the materials stored. For example, you would not want to store an acid in secondary containment made from metal.  
The containment must be able to hold 110% of the contents of the single largest container stored in it; it is assumed that only one container will be leaking at any time.  If the material that you are storing is flammable, such as methanol, a "flammables" storage cabinet with secondary containment built into the bottom is a good option.   
In some cases, the building itself can serve as containment.  
If you store materials in a building with a concrete floor with no floor drains, and there is a step up to the door or the floor  is sloped away from the door― that is, the material would not flow out the door― then this building serves as containment.  That doesn't make it any easier to clean up a leaking container, however, since your floor may be covered with oil.  
Another way to provide containment is to construct a dike around the stored materials made from concrete block.  It's important to make sure the dike is well sealed to prevent the material from leaking through.  This will at least isolate the spilled or leaked material in one part of your facility.  
Purchased secondary containment for 55-gallon drums can include a grate to suspend the drum over the containment area for easy loading and unloading. This also allows you to easily look through the grate to see if the material is leaking.  This type of containment can also be designed for use outdoors with a rolltop cover to keep rain from contacting the stored material and from getting into the containment area.
Some inexpensive-but-adequate methods of secondary containment include using empty buckets for bottles and small jugs, plastic trash cans for larger jugs and small drums, and even kiddie swimming pools for barrels.                     
Contain your spills, but not your enthusiasm!

Lysa Holland, P.E. is an environmental compliance engineer at Penn State University. She co-authored the Best Practices Manual for Small Scale Biodiesel Production, available at http://pubs.cas.psu.edu/FreePubs/pdfs/agrs103.pdf