Oil/water separators - Difficulty meeting state wastewater standards



I work at a remanufacturing plant - tier 1 OEM supplier to Ford and Mazda. Preventive maintenance and some environmental issues are QA responsibilities here.
I am having difficulty meeting state standards for oil and grease in wastewater discharge. We use a standard type of separator that is fed by a large sump tank. The reason for the sump tank is that tranny fluid tends to emulsify rather than separate. So we slow the flow of waste by routing drainage through the sump rather than directly to the separator. Does anyone know of a large capacity, in-line, coalescing filter i could plumb into my outflow line? I am normally just slightly out of spec (spec = 100mg/l = 100ppm). I need something to catch that last lttle bit of emulsified transmission fluid.
Bruce Newman

Bruce Newman
MNAO Remanufacturing


Super Moderator

Give me a day or 2 and I'll see what I can locate for you.

We maintain a fleet of over 3,000 army combat vehicles from Humvee's to M1 Tanks, and we have some of the same issues here with fluids.

Remember this...a key element of 14K is prevention of pollution and not pollution prevention...."eliminate it at the source".

Look at your processes. What can you change to reduce the initial amount of fluid going into the water system?

"Continual Improvement" whatever it is that you are doing, can you do it better?

Filtration is fine, but are you creating another waste stream (the contaminated filter media)?

Just some things to ponder ....

I'll try to get back.

Randy Daily

Jon Shaver

Good thinking, Randy. Reducing/eliminating at source is the way to go, whether its for ISO14000 or not.
Do I understand your problem correctly, Bruce, that your separator isn't working quite as well as you want? ("slightly out of spec"). If so, then why not just change the spec? Really. Its probably a permit issue. Why does the State say 100 ppm? Why isn't 110 OK?

[This message has been edited by Jon Shaver (edited 07 March 2000).]


Super Moderator
1st - Thanks for the kudos Jon...

2nd - The state in question probably has set it's limits based upon the EPA's guidance on pollutant discharge levels....no leeway believe me, it's part of what I do everyday here in California.

3rd - OK Bruce here's what I can offer....If you have no other recourse you are best served in my opinion in chemical treatment of your waste water. There are readily available process's (coagualtes) that will cause the waste fluids to come together for easier removal. Remember though, water is kind of like air when you want to clean it...the 1st 95% of the crud is pretty cheap to remove...the last 5% increases in cost geometrically by each percentage poit thereafter.

You will also be starting a new hazardous waste stream, increasing personnel and maintenance costs, and possibly capitol expenditures for new or upgraded equipment to utilize an improved cleansing process.

Your best and least expensive choice is to reduce the polluting agents at the source.

If cleansing of materials is being done with solvents or soaps ...stop it. Your emusified fluid is starting at that point. Don't let soaps or solvents into your waste stream...don't believe the crap about biologically safe or environmentally sound. When you let solvents or soaps into oil recovery systems..the usefulness of the system is negated at that point.

We use high/low-pressure steam cleaners on all the equipment we maintain for the Army. If you can clean the carbon and crud from an M1 Tank that way....auto parts have got to be easier.

Randy Daily


You guys have been a tremendous help. I have long recommended doing away with soaps in the wash (ultimately waste) stream. Production guys just can't seem to get past the need for soaps. I did a DOE some years ago that indicated the only important factor in cleanig parts is temperature. I will use your arguements to back my position.
By the way, the 100 ppm is a state (FLA) spec and is not negotiable.
Bruce Newman
QA Supervisor
Mazda North American Operations, Remanufacturing
I welcome further discourse on this subject.
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