Construction Vehicle Wash Facility using recycled wash water

[jartgo]

Does anyone have any experience either operating or designing a facility such as this? The idea is that it's not intended to get vehicles clean, just knock the mud and dirt off. And we're talking tracked machinery and other heavy duty equipment.

I've got it laid out now almost as a septic tank would be except I have three stages of "oil/water separation" and it is open to atmosphere...from there it will gravity drain to a sand filter and then into a large pump tank. I'm considering doing away with the sand filter, as it really doesn't matter if the water is clean when it comes out of the gun. My concern is with issues such as pressure gun clogging, odor control, etc.

Anywho if anyone has an operational or design insight, please send your thoughts my way. Thanks.

 

[Drumchaser]

jt

I hope you have checked with your local regulatory agency for this kind of set up. (the discharge end)

If your large pump tank is for hauling the bad water off and you have a site that will take it (for a price), maybe you will be ok. As long as your wash bay water does not enter a local storm sewer system, ground infiltration, or ditch (sounds like you have this accounted for) maybe all is well.

We have wash bays like this where I work, and they are constantly clogged.

 

[concretemasonry]

You may want to look at the companies that supply wash-out and recycling equipment for ready-mix concrete producers.

They use a system of sophisticated settling tanks.

Their goal is to reclaim and separate aggregate from other materials (cement, admixtures and some oil). These are approved systems regarding the discharge. They are also pricey.

Dick

 

[Bribyk]

You still want to filter the dirt/sand out well otherwise it is going to sandblast everything from the pump to the washgun nozzle to the paint/glass on the equipment.

 

[jartgo]

There will be no direct discharge. The pump tank will feed the wash system (the wash water is reclaimed).

The dirt/sand and other solids will be settled through a series of oil water separator type settling bays (four stages). The water may be turbid, but I don't expect there to be any solids.

I'll check with the concrete washout folks for their system layout.

 

[bimr]

You will need a high pressure pump to spray off the debris. These types of pumps must have tight tolerances to get the high pressure.

For liquids, such as reclaim water, increased filtration is necessary to avoid drawing abrasives and suspended particles into the pump.

http://www.hydrotek.us/teksheet/ts-recycle-rpmmu.pdf

 

[chicopee]

What we had to do in our job site to clean dump trucks of contaminated soil after the trucks dumped their loads in stockpiles, was to designate an impervious area (asphalted surface),protected from rain,ie, under a bridge where we sprayed the trucks with a hand held power washer. The designated area had a curb so as to contain and guide the runoffs from the rainse operation and wet stockpiles into an underground concrete tank incorporating three compartments and a submersible pump placed in the last compartment. This pump would drain automatically water into an aboveground steel tank. Water in this AST would be tested for contaminants and disposed accordingly. Soil deposit and floating oil in the concrete tanks would be removed with a VAC trucks and properly disposed.
Surprisingly, the UST and AST had to be cleaned only twice during about three years of project. Most of the water evaporated. Mud and debris from the rainse operation would swept with brooms into the stockpile. The stockpile would also be covered with plastic sheathing to minimize dust from blowing around.

 

[jartgo]

thanks bimr. I guess I'm looking for that "fine line" deciding how much filtration is necessary. I'll get in touch with these guys. Have you used or seen there equipment before? Looks just like a pressure filter like you'd see in a groundwater treatment plant.

 

[bimr]

I don't have any experience with this particular vendor. You probably would want to find a local single source for the equipment so that you would be able to get service.

The high pressure pumps are low flow, high pressure so the cost of a filter system should not be that expensive.

 

[Horaz]

I don't have specific experience however have done some research. I have seen used the type that you are mentioning, as well as much more advanced treatment systems. One that I had looked at is Pan American Environmental VEW (Vehicle Equipment Washwater Treatment Systems)

A suggestion which you may already have incorporated, is to have a separate settling tank, with multiple chambers, then a separate pump tank.

 

[jartgo]

yeah I have a seperate setting tank with multiple chambers and a separate pump tank "clear well." What to do in between the settling chambers and pump tank is what I'm messing with now. At this point, I'm leaning towards designing my own pressure filter system, which would be similar to the hydrotek one, albeit much less elaborate. Thanks for all the suggestions.