top of page

Diving into Oil Water Separators

TT OilWater Separators(1).jpg

Tank Talk dives deep into the world of bulk fuel systems with the revival of a listener favorite: Oil-Water Separators(OWS). This episode provides an informative exploration of the mechanics and importance of OWS Systems in fuel storage. Shannon discusses how these systems are essential for separating oil from water to prevent contamination, detailing the operational principles, maintenance best practices, and environmental significance. She also tackles common challenges and the latest regulations impacting the use of OWS systems in Alaska. Whether an industry professional or an enthusiast eager to learn more about bulk fuel infrastructure, this episode offers valuable insights into keeping our waterways clean and fuel systems efficient.


ADDITIONAL RESOURCES:
SPCC Guidance for Regional Inspectors

EPISODE TRANSCRIPTION:

Amanda

Welcome back Shannon. How are you doing this morning?

Shannon

I'm doing really, really well. I am enjoying all of the sunshine that we're getting lately. It's a good day to talk about tanks.

Amanda

Always. We've been getting some questions about oil-water separators, and it sounds pretty obvious, but I've learned that nothing is as easy as it sounds. So tell me a little bit about oil-water separators. What makes them complicated, and how do they interact with regulations?

Shannon

Well, let's start with the definition of an oil-water separator. An oil-water separator is a simple machine. A lot of people think of them as a tank, but they are not a tank, they are a machine. Well, tanks are machines too, but an oil water separator is a different kind of machine, so it is a container of some kind, rather. Sometimes they're rectangular, sometimes they're cylindrical, sometimes they're oddly shaped to fit into weird places, but they are a container that has baffles inside and it uses the physics of fuel floating on the top of water, because fuel has a lighter specific gravity than water. So it floats on top and it utilizes baffles and piping to allow fuel to be trapped on top and water to flow through the oil water separator and out the other side. Oil water separators are a passive system, and so they typically are something that works, no matter what it doesn't. You know, if they stop working, it will not stop you from working.

 

For oil water separators, there's a couple of things that we always run into with record keeping, maintenance and operations, and then they also are a little tricky with how they're regulated.

 

Oh, what makes them so tricky? Well, so some regulations are very specifically clear about oil water separators, but a whole lot of them ignore them completely in the regulation, and then they have more like guidance documents about how to treat oil water separators, because an oil water separator looks a whole lot like a tank and it could theoretically hold a lot of fuel if it was full of fuel instead of water, and so we see them treated a little differently under different regulations. For example, the Spill Prevention, Control, and Countermeasures Plan, the SPCC that the EPA requires under 40 CFR 112, they have a whole chapter in a publication that they have. It is the SPCC guidance for regional inspectors that was published last in 2013, although there have been updates along the way. They have a whole chapter five on oil water separators and how to treat them. Within your SPCC and a lot of our clients have you know they have to be very specific about what they use these oil water separators for and how they operate and maintain them to meet the requirements of the SPCC.

Amanda

So what happens if they're not maintained or if water gets through?

Shannon

Well, one of the complications we see for oil water separators is if you live in a place that freezes and there's a lot of water in your oil water separator because there's always what's called the charge to an oil water separator, it has at least a third of its of the oil-water separator is filled with water so that the fuel has something to float on, and so if you live in a place that's cold, that water can freeze and damage some of the internal mechanisms like the baffles or the piping, and so the oil water separator you think is working, but it's not, because some of the baffling has been damaged or perforated or your piping has become damaged and it's no longer at the right level to allow water through but not fuel. The other thing we see with oil water separator maintenance is that people never check them, they forget about them, and so years and years and years will go by, because it's, like I said, a passive system, so people don't need them to operate, and then when you do crack them open, you see several years of weeps, drips and leaks all gathered in there, and if there's enough fuel in an oil water separator, it will push out that bottom third of water and it will begin discharging fuel. If it's completely full of fuel, fuel will flow out of the oil-water separator. So that is something that trips people up a little. I think they either forget that it's there or they believe that it's going to magically contain all the fuel no matter what, and then maybe it'll stop discharging if it's full of fuel.

 

And some oil-water separators have valves that you can close. Some of them do have sensors that tell you when they sense hydrocarbons. But again, if you don't maintain those sensors, if those sensors are 10, 15, 30 years old, they may not alarm when they interact with hydrocarbons or the power to that sensor may be gone because the wire corroded. I've seen that a lot. Where there's the power to a sensor, and the sensor actually looks pretty good, the actual wiring itself has corroded or become disconnected. Or my other favorite is that it was beeping all the time or alarming all the time, so somebody just disconnected it or pulled the plug. Have enough.

Amanda

Right.

Shannon

Yeah.

Amanda

So, what complications do you come across with oil-water separators from a regulatory standpoint?

Shannon

Yeah. So back to that chapter five of the EPA guidance for SPCC's. You need to meet a couple of conditions for the EPA to exempt your oil water separator from the same requirements as a tank. And so if it's truly an oil water separator and you're not using it as part of a treatment process or you're not using it as part, like to actually store fuel in some manner, I have seen some people modify oil water separators to where they're basically storing used or waste oil in them. If those are not what you're working with and instead it's just a, it's part of your facility drainage, right, like you drain everything from your secondary containment area through this oil water separator prior to it going to the shoreline or to ground, the EPA allows it to be exempted and it does not count towards your facility overall storage volume and it does not have the same secondary containment requirements that, like your tanks would Right. So if you have a 1500 gallon tank, it has to have 1500 gallons of secondary containment. If you have a 1500 gallon oil water separator, it's considered part of your drainage equipment and so it does not have to have secondary containment.

 

And we see a lot of confusion with that. I have absolutely seen SPCC's written where they've included the oil water separator like it's a tank. But if you read the guidance and you go by chapter five, it's clearly exempt. You just have to have gotten into that guidance and we can. Actually that's a publicly available guidance. I think everybody who operates an SPCC or within one, should read it at least once. I mean it's not a thriller by any means, but there's a lot of clarification in that guidance for some of these areas that 40 CFR 112 is just silent on. They don't say anything about oil water separators and that regulation.

Amanda

How frequently does the EPA check on oil water separators?

Shannon

The EPA does perform inspections and virtual audits, they are very inconsistent with the timing of these audits.

 

So many facilities will go entire lifetimes or careers without any EPA scrutiny or involvement and other facilities have had multiple interactions with the EPA.

 

So it's sort of random and inconsistent which can feel a lot like never to some people.

 

But what we see on our end is if you have events such as a spill or something failing or you know something where you have to call in and report things, those kind of events increase your scrutiny and you almost certainly will get a virtual audit from the EPA on top of all the other stuff you have to deal with from having the event. And so that's when we get brought in a lot to clean things up because they have not paid attention to it and then an event occurred and now it's important all of a sudden. So we recommend to everybody have somebody knowledgeable review your SPCC it's supposed to be renewed every five years anyways, but make sure that somebody who really understands what they're doing is going through there and eliminating all your risk. And this oil, the specific tiny, microscopic look at the oil-water separators, is just. You know, it's one of the many things that people who write SPCCs have to look at, but it's not necessarily as clear-cut as people think, right?

Amanda

What are the record-keeping requirements for oil-water separators?

Shannon

That's a really great question. If you're operating under an SPCC plan, you need to have documentation of periodic and regular inspections, and that can be pretty variable. We typically recommend at least an annual inspection. That includes opening it up, inspecting all three chambers and the outfall and making sure that everything's working correctly, so that that secondary system is working and you can clean out. If there's any fuel floating on the top, you can clean it out.

 

For another podcast episode we can talk about water quality standards and oil water separators, but for today let's just talk about routine operations and maintenance. And then we also encourage people that have extreme seasonal fluctuations to maybe do a twice a year inspection, sort of like once in the spring to make sure no damage occurred during the winter and then once again in the fall, before you put things to bed for winter, to make sure you're not going to be causing any damage. And then it also depends on the frequency of use for oil water separators. Some oil water separators, like the ones we see that are attached to large bulk tank farms. They process a lot of water and very, very little contamination right, like maybe some leaps or leaks or drips from something that's dripping. But some oil water separators are not part of a facility containment discharge. They're actually inside a warehouse or shop and they're meant to treat stuff that's coming through a shop drain.

 

And so if your oil water separator is undergoing way more frequent use or is going to have heavy use, you may want to be inspecting that on a monthly basis just to make sure that you're not overwhelming it or putting too much stuff in there.

 

And yeah, it just sort of depends. But if you decide on a routine whether that's once a year, twice a year, whatever you need to stick to it and you need to make sure it's actually documented, like it can't be a visual and the guy says, yeah, it's good, you need to actually have a piece of paper that says I inspected the following components of my oil water separator and the bare minimums are an inspection for each chamber chamber one, two and three, an outfall and then also inspecting if there's any drains that go to it, making sure you're inspecting, like all the inlets, basically. And then if that oil water separator has a sensor for hydrocarbon sensing or if it has any other equipment that helps you know when it's full or when hydrocarbons are in it. All of that has to be working and tested and verified as working and tested annually as well, and that needs to be written down somewhere, not just visually confirmed.

Amanda

And that's all included in the SPCCs with integrity. Yes, yes, we absolutely provide guidance.

Shannon

And we can even provide example forms for your oil water separator inspections, no problem. And when we perform our SPCC site visits like when we're creating an SPCC or updating we often because we pay attention to oil water separators probably a little more closely than many groups do we often correct or we not correct? I don't want to say correct, but we get better descriptions of the oil water separator and the volumes of them and how they work and where they discharge to, and those can all be really valuable if you have a spill event to your drainage system and nobody's really sure where the oil water separator goes to. Like we can help you understand that before you have an issue and so all of that's ready for spill response when you need it. Beforehand, instead of after the effect, try to figure out where it's gonna come out.

Amanda

So it sounds like there is a lot of potential for preventative measures there with the oil-water separators.

Shannon

Yes, all passive systems do better with preventative maintenance and proactive monitoring and inspections.

Amanda

All right. Well, thank you so much for joining us again today and sharing some information on oil water separators with us. Are there any additional resources that we can find online? Yeah, absolutely.

Shannon

We will post the EPA's SPC sequence original inspectors on the show notes and for your oil water separators. Some of the best sources of information are construction schematics and drawings for your facility. A lot of them have all of the details in there and you can look up the volume and how it's plumbed and where it drains. It's all part of that construction documentation. So if you have those, they're really important to retain because that kind of information gets lost over time.

Amanda

All right, well, thank you so much for joining us today, shannon, and we look forward to our next chat, yeah glad to have happy to do it.

Shannon

Oil-water separators are funky little machine and we deal with them quite a bit, so I'm glad to put more education out there.

bottom of page