Wash Bay

[Tugger2]

Im looking at putting a decent wash bay in at my shop. Im thinking 20X40 with a 40 ft. seacan down each side and a roof. Id like to slope the floor into a trench down the centre to a sump that will catch solids ,then drain liquids into another sump that will separate oil .
Is it concievable to filter the residual water and recirculate back into the washer , say 3 to 5 gal /minute without a million dollar treatment plant? This would help reduce discharge . All my surface water around the shop currently runs in to catch basins i built from 18" pipe and then into a 2 chamber 1200 gal sump before discharge into the street ditch. So far it seems pretty clean ,but in todays world there seems to be no sweeping this stuff under the rug.
Any ideas ?

 

[Nige]

A simple 2 chamber system ought to work. Set the weir heights right and the silt will settle in the first compartment.
The water & oil mixture spills over into the second compartment and you suck the clean water for the washbay from close to the bottom.
The oil floats on top and you can extract it with a Skimall or similar. https://www.skimtech.com/about-skimtech

 

[Tugger2]

That looks like an interesting rig. How about filtering the water prior to running thru a hot water washer ,think thats necessary ? Im thinking of buildup of residue in the coils of the heater.

 

[Nige]

That looks like an interesting rig. How about filtering the water prior to running thru a hot water washer ,think thats necessary ? Im thinking of buildup of residue in the coils of the heater.

That’s why you have the suction from the 2nd compartment set about 12” up from the bottom.

Provided that the first compartment is large enough and you clean it out at the correct intervals there should be little overspill of “dirt” into the 2nd compartment, and what little does spill should lie in the bottom. Even though the 2nd compartment is the supposedly clean one it will still get some dirt into it.

If you’re really worried about sucking dirt fit an intake filter in the suction line.

 

[skyking1]

If you set it up with a trench drain across that low end, then a type 30 CB, most of the dirt will be there before it goes into your oil water separator. the big stuff will be in the trench drain and you periodically clean out, then you clean the CB and the first chamber of the oil water. I would suggest you place the catch basin and oil water separator in an area that is not roofed. That way any vac truck has good access.
Alternatively you can rent a vac trailer and those will go anywhere.

 

[Delmer]

Two ways of thinking of the trench, either across the low end like Skyking said. Or down the center like you said, I prefer down the center because it's closer to sweep or rinse it, and you can have a better slope to the floor to get more dirt to rinse into the trench on it's own. The downside is the longer trench won't have as good of slope as easily, I like that because you can shovel the dirt out of the trench by removing one section of grate and sliding the others back as you go, then put the one you took out back in at the other end of the trench. Or you could make the trench deep enough to get decent slope and vacuum out the dirt, seems more complicated than it's worth to me. You shouldn't need heavy duty trench grates if you only drive down the center of the bay. Or use the narrow plastic grates that a tire would span anyway, and cut a custom shovel to clean the trench.

 

[CM1995]

You may want to consider a sump between the trench drain and oil/grit separator as another layer of filtration. Basically a 48" pre-cast manhole with a 3-4' sump at the bottom. The trench drain water drops from the top of the manhole and the discharge to the separator is 3-4' off the bottom. Turn a 90 down on the discharge line like a septic tank to keep any floatables from entering the separator.

You can find used or left over manholes for sale - heck I've got one a 4' base my yard with 2 manhole cones but the shipping would getcha.

 

[mitch504]

We drop them in the ocean to make reefs all the time, I'd give you one free and clear, but I'm 10hrs further away than CM is...

 

[skyking1]

that was what the type 30 CB was for. They have about 2' of catch. Heck you could pan and grade the slab to it and eliminate the trench if you liked.

 

[Tugger2]

I like the idea of a trench that i can scrape out with a smooth edge bucket on my excavator.
I have even though of a deeper grease pit with a grating floor in it. It would be nice to get under some of my stuff and clean it to.

 

[Nige]

We always made the "mud compartment" with a sloping entry at one end that a skid steer could get in & out of (or a wheel loader for the bigger ones) to muck it out.

This is the sort of thing I am used to, but you could always make a scaled-down version of it. The muck/water mix falls into the first compartment and the clean water is pump out of the last one. it's all a matter of getting weir heights right.
https://www.aegroup.com.au/projects/mining-wash-bay-project/

 

[Sberry]

You need clean fresh water to go thru burner and washer pump.

 

[Tugger2]

Geez Nige , I dont think i could fill a pit like that in the rest of my career .
It almost seems that washdown with a hose and hot water pressure washing need separate places to be done.

 

[Tugger2]

View attachment 233487 View attachment 233488 View attachment 233489 You need clean fresh water to go thru burner and washer pump.

Is that a steam cleaner or hot water pressure washer?

 

[Sberry]

It can do either but i never steam. Hot pressure wash. Its a good unit. If i was young and hiring men would get 1 size bigger and run on L.P. vs diesel. 5 gpm cuts ice well.

 

[Nige]

Geez Nige , I dont think i could fill a pit like that in the rest of my career .
It almost seems that washdown with a hose and hot water pressure washing need separate places to be done.

I did say you could scale it.....!!
Just that those photos were the first ones I came across. Based on your OP you could potentially drain the surface water into the system and operate 100% with rain/recycled water.

There are plenty of hot water pressure washers around that will run quite happily on recycled water.

 

[Sberry]

I have one in a truck. 4 gpm, hot with 500 gallons of water.

 

[Tugger2]

Looks like time to get on the drawing board and cost this thing out

 

[Sberry]

I am not sure how well a guy would need to clean the water, oil, brine, dirt thru the coils and pump. I am sure there is a way but we dont live in a place with expensive water.
I lost old pics but built several for trucks, they actually did heat some light brine at times but a couple of them 11 gpm and million btu burner. Saddle tanks on trucks for fuel.

 

[Sberry]

It's an expense but there is no substitute for being able to hot wash. My solvent tank washer fluid stays clean and only use it a little. I did injection pump the other day and plugged the ports and got it surgically clean outside before we ever tear it apart. I wash a fuel tank out for repair and had it clean the same way before I top it.
Rare day I don't wash a car. I have hose thru the wall with outside controls. Flim switch and am washing.