How Do You Manage Wastewater?

I use my plasma cutter about once a week, therefore I have no desire to leave the water in the table when i’m finished: the bacteria, the rust, humidity and the smell that it fills my shop with, no thank you.

What do you do with your wastewater?
How do you dispose of it? Clean it?
How often? What is the cost? etc…

I’ve done some googling and searched around and I’ve discovered some different options that commercial businesses use:

#1: use that green fluid, and then set up a circulation system with a particulate filter, and simply reuse the water indefinitely, while managing the pH balance and replacing the particulate filters when they are full

#2: let the particulates settle out of the water, then those are scraped-up and thrown in the scrap bin with the other metal scrap, then the “clean” water is dumped

#3: set the water outside and allow it to fully evaporate on its own, then scrape up and take the particulates to the scrap bin

#4: convert to a downdraft table

Anyone have suggestions or advice, please share!!!

if I somehow missed an existing thread about this while googling, please feel free to link to that thread.

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I just drain the table into buckets and pour it out. I just use plain ol water. I then clean out the debris from table and discard into trash…


Welp, turns out i actually joined a thread last year about this same question :joy::rofl:

only these guys are more focused on the system that removes and replaces the water, and there’s really not many answers about managing the waste itself.

I’d really like to know more about how people actually manage the wastewater when they have to remove it.


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I haven’t disposed of any yet, because I have a drain tank and recirculate it back into the table. If you just use plain water, there shouldn’t be anything toxic in it. I plan to just pour it out in my yard. My grass should love the extra iron.


Do you have a way to scoop out the tank once it gets too much slag settled in the bottom?

I’ve got the green stuff but since my water evaporates rather quickly I put some borax in it to prevent rust and it evaporates and repeat as necessary. I don’t see the need in having all the pumps and tanks.


How fast does it evaporate? Would you say it loses a gallon a week, or?

Don’t know how many gallons but I can fill it to about 1/4" from the top and in less than 3 weeks it will be 1/2" below the top of the slat holders.

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I drain, let it sit and settle, pour off the “clean” water, dry, scrape residue into my scrap bin. (looking forward to building the drain/filter/fill solution though. :slight_smile:

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My tank is a large plastic tote with a lid on it, so I can clean it out if necessary. I usually let the water settle in the table for a day before draining it, so most of it stays in the bottom of the table. When the table is dry, I scrape up the debris with a 6" drywall taping knife and scoop it into a trash bag.


Do you have a link to the pump motor you use? I really like that setup, simple and cheap! And i’m already halfway there as i have a very similar PVC drainpipe setup. Might use a 20gal salvage drum instead of a tote, though :thinking::thinking::thinking:

I used this pond pump from Harbor Freight.

The cheaper ones didn’t have a fast enough flow rate. This one fills my table in about 5 minutes. When it is about 80% full, I shut off one of the drain valves and let it finish filling from one side.


all very good option…replies…and suggestions…there is a lot of information on the forum for water table mods…

I use air pressure, not a pump to fill my water table, then gravity drains into the storage tank. I can use the same air pressure to force the spent fluid (homebrew mix) out the hose fitting at the bottom.
Posted here:


toolboy… yes, agreed.

my specific question was for the wastewater itself, it seems like most of these guys either dump it, or let it settle then remove the slag.

the problem with the megathread on the tank solutions is that they’re focusing on complicated and expensive solutions, and very little mention of how to manage the waste products themselves.

i really appreciate everyone’s advice and help. :slight_smile:

I use plain water with some borax. Drain it and every once in awhile when I notice a lot of precipitate in the tank (or buckets when I used those) I just dump it all in the dirt on the side of the driveway. The pine trees don’t seem to mind. There’s nothing toxic in there. Anything left in the table gets vacuumed up & tossed in the trash.

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by waste products are you talking about the metal slag in the bottom?
the type of water and the chemicals used?
or Both?

The actual wastewater drained from the table is my primary concern, as it has an extremely high concentration of metal particulates. I don’t personally use any chemicals, yet, just plain water for now.

I actually have a really cheap water filter…Rainfresh…although I circulate my table water it could easily be used when draining water to remove particles…
let the water stand in the table a couple of hours…drain it into a bucket…put a strong magnet in a zip-lock baggie…dunk the magnet in the water to pick up the rest of the particles…then when you remove the magnet from the baggie you have clean magnet and clean water


oooooohhhhh i really like the magnet and bag idea, gonna order a magnet right now, haha