Why Use a COLIWASA?

Coliwasa“COLIWASA” stands for composite liquid waste sampler. The COLIWASA is a device for obtaining a representative sample from stratified or unstratified liquids. It is commonly used for sampling containerized liquids, such as tanks, barrels and drums. It may also be used for pools and other open bodies of stagnant liquid. However, it is not recommended for moving liquids. The COLIWASA obtains a vertical column of liquid representing an accurate cross-section of the sampled material. When sampling, utilize the correct type of COLIWASA for the sampled material.

I bring up the subject as I’ve encountered numerous generators who improperly sample their waste. This can lead to an inaccurate representative sample and faulty analytical results. The end result can be an improper waste determination that is a violation of the regulations. Worse yet, someone could be injured.

Years ago, I happened to visit a generator while they were extracting a sample from the bottom valve of their 2,000-gallon vertical tank for analysis. Primarily water, the sample was extremely clear. I asked how they accounted for the top and middle sections and got a puzzled look back. I retrieved a COLIWASA, took a sample, and found about a four-foot layer of Jet A and diesel fuel as a result.

At another site, a generator asked me to take some acid samples to a lab for their annual sampling, which included PH and RCRA 8 Metals testing. Upon further discussion, I found out they were just scooping the liquids off the top. Therefore, I suggested using a nine-foot COLIWASA to acquire a representative sample. The analytical results showed a measurable increase of three regulated metals which were then added to their waste profile.

In conclusion, using a COLIWASA can be instrumental in taking a proper representative sample, making accurate analyses and determining the correct waste(s). This can minimize potential fines, endangerment of personnel and, potentially, damage to the environment.

– Rusty Lea, Account Manager