What is engine oil residue that sinks in water?

[oldestguy]

In our little town, the sewer cleaning guys opened up some Our little town just started cleaning the sewers. At the head end of one line they hit a "storage" sewer lateral from an old auto service place. There apparently had been a plug in a lateral. A mix of water and black sludge of 500 gals was sucked up. It is sitcky stuff and smells like used engine oil, is thick and settles in water.

It probably is the result of them disposing of engine oil down a floor drain through the years, but this finally probably plugged and became a storage "facility" until the sewer cleaner disturbed it. Our state DNR says it is a local problem. It will be tested now before disposal, but any ideas?
Sewage dispoasl facility is a lagoon system. So far no evidence of it "floating".
I'm an interested retired geotechnical engineer, but we do have a regular engineer working on this. He is mistified right now.

What would you test for?

 

[francesca]

Diesel engines accumulate a lot of carbon in their oil. I imagine that would sink.

 

[greenone]

Have you asked the disposal facility what analyses they require to characterize the material?
VOCs, SVOCs, PCBs, TEPH, TVPH would be my guess.

 

[bimr]

There are all sorts of fluids in an auto shop, not just motor oil. You also have high viscosity gear oil for example. Here is some online information.

Sedimentation/Sinking
Some heavy refined products have densities greater than one and so will sink in fresh or brackish water. However sea water has a density of approximately 1.025 and very few crudes are dense enough or weather sufficiently, so that their residues will sink in the marine environment. Sinking usually occurs due to the adhesion of particles of sediment or organic matter to the oil. Shallow waters are often laden with suspended solids providing favourable conditions for sedimentation.

Oil stranded on sandy shorelines often becomes mixed with sand and other sediments. If this mixture is subsequently washed off the beach back into the sea it may then sink. In addition, if the oil catches fire after it has been spilled, the residues that sometimes form can be sufficiently dense to sink.

http://www.itopf.com/fate.html

You probably should just call safety kleen or a similar firm and have them test and dispose of the substance.

 

[dicksewerrat]

The oil sludge contains sand, grit, metal shavings, heavy metal particles(from bearings) and then there is some standard sewage. the ligther components of the oil flowed away some time ago.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com