safe disposal of chemicals

Some of these things are safe enough to dump on the ground if there's good absorbtion, which is the same as putting it in the septic tank for most purposes, with small amounts. One can dig a small pit, fill it back up with crushed limestone, and pour DILUTED waste acids in there. The limestone will neutralize it. This works fine for SMALL amounts, when you don't have significant amounts of dissolved toxic metals. neither the copper or silver that might be in there will be that much of a problem. nickel is more toxic. And some of your other chemicals may be also not allowable in the ground as is. You should check with local regulations as well, to find out what's recommended in your area.. Much of the question revolves around the amount of chemical you're needing to dispose of. Much of the time, you're not disposing of chemical, just rinsing an item that's been in an acid cleaning bath, and it's only the runoff you worry about. This can be helped a lot by using a seperate small rinse tank of clear water, which is itself replenished with clean water as evaporation etc requires, and this rinse water is also used to replenish evaporation losses from the main containers. In this way, the amount of "drag out" chemical that actually gets beyond that system into the waste water is almost negligably small for the types of chemicals, in small amounts, that you'll be using.
Again, whether this is a solution depends much on the individual chemicals. remember that a septic system is not a toxic waste treatment facility. Primarily, it's designed to dispose of biodegradable wastes, and little else. Chemical disposal through a septic system simply spreads the chemical out in the septic field, often little changed. Whether this has any effect or consequence depends on the amount and type of the chemical. In some cases, it can kill the biological activity of a septic system, with unpleasant results.
Another method of disposing of such things is to simply put it in an open wide container with lots of surface area, protected as needed so children, pets, or others don't get in, etc. Then just let the water content evaporate. Accumulated dry waste chemical would need disposal at local facilities, but would require it much less frequently.
Again, it depends on the chemical, and what you've dissolved in it. pickle as used by jewelers to clean oxides from silver, gold, or copper alloys, is generally fairly safe when dilute. Baking soda can neutralize it, as can the aformentioned limestone filled pit, but neither does anything to dissolved metallic contents, which may or may not present a problem, depending on which metal and how much there is. Your photo chemicals may be more of a problem, as can be some etching solutions.
Use "spa down", not spa up. What you're looking for is sodium bisulphate, which is a sulphuric acid salt. It is safer than using an actual sulphuric acid pickle. Note that buying this as the pool chemical is only a means to save money. It's the same chemical as is sold by jewelry supply houses as normal pickling chemical for silver, copper, or gold work. It has the advantage of being lower priced as the pool chemical, as well as, oddly, being purer when purchased in this form. Some of the brands (Sparex especially) of commercial pickle are quite impure, and mess up your container more quickly.
As I said, this stuff is safer than Actual sulphuric acid, but it still can burn holes in clothing, and fumes from the stuff when hot/boiling, in a closed unventilated space, are not so good. Safer pickles, though considerably slower, can be made with weaker acids. Citric acid, which can be purchased as a food grade chemical, works reasonably well, especially with silver and gold work. Less effective with the thicker oxides you get on copper, but it can still work, if you're willing to give it more time to work. Citric acid is generally considered to be pretty harmless in the dilute form you'll use it (just as it is in food). Either citric acid or sodium bisulphate pickels can normally, when diluted, go directly into a municipal waste water system. But you should check to see what their effect would be on a septic system. Septic systems are, as i said, a very different problem, since they are a living biological system, and more is involved than simply the toxicity of the chemical.
Again, key to the answers are the quantities involved. Most of the chemicals you're using are not frequently disposed of, for example, and most of the issue is simple rinse water from pulling things out of the chemical and rinsing. You can deal with that with the rinse tanks I suggested. For the rest, you really need to check local regulations and requirements, as there are many variables beyond just the chemicals themselves.
Peter

"lisau" wrote: (clip) I want my metalworking to be as "green" as possible. Any comments on this issue would be appreciated! (clip) ^^^^^^^^^^ Where I used to work we sold a system which could help you. It consisted of a metal 5-gal pail with a heater wrapped around the outside. It had a close-fitting plastic cover with a small fan, blowing air across the contents into a duct to the outside. You would empty your nasty water based chemical solutions into the can and just wait for the heat/air flow to reduce them to a dry concentrate. When the can got full, it went to a toxic waste disposal service. I don't know whether this lash-up is still on the market, but I don't think it would be hard to build one, and a lot cheaper, at that.

I've had luck with the classic vinegar + salt solution. Even etches the surface of the (brass/bronze/copper) and shows a crystalline appearance... oh, castings BTW. All the worse though since you guys are just soldering, I'm melting the whole thing. :) (Unless you're casting a ring or something of course, but then agian, I don't do things as small. ;)
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

Can you clarify your water supply to your home? are you on mains as we call it here in the UK or do you rely on a spring.? If you rely on aspring etc how many gallons in 24 hrs do you think you can draw? or are you using a well? you need to look at your total water cycle if like me your possibly completly independent for water. IE where yourwater comes from what the flow gradientof the water might be and where it ends up. Ive been a metal craftsman for some 36 years and at my present place for 33. we arewholly independent here also out in the boon docks for all our services so weve had to think very carefully how we treat out own back yard. we have a septic tank too, but my chemical wastes are minimal. Mostly sulfuric acid pickles containing copper and zinc metallic salts. I dispose of say 2 to 3 gallons a year of this into a chalk pit well downstream of any rainwater ditches or near my house. below thepit is clay where the ground water is well below any possibility of leaching into surface ditches . My water supply comes from a spring up hill from the house and comes from a sand water bearing aquifer overlaying clay. This water is affected by the local acidheathland so is acidic in nature. In fact it corrosive to the point that a galvanised tank will lose its zinc coating in about 6 months. So all our plumbing has to be either pure copper or stainless steel. 316 grade. Brass will dezincify in about 5 years. leaving a brittle copper sponge. Never had any infections or ailments in 33 years from the water. Its also quite untreated except for filtration. Peter has covered just about all you need to know. If in any doubt take the waste to your local recycling /dump and ask the manager there what they do with waste acids. At out dump, some 6 miles away, all old car batteries go into a large plastic skip so you could put your acid plastic containes into one of those.
lisau wrote:

Or you could build a wetland to take care of your problem.
Shawn

Any etches like that will wind up with metal ions in solution when they are spent. If you dispose of them into the ground you will be leaving yourself open to trouble in the future. I would not do this.
I know I will take a bit of flack here for taking such a hard-line approach but consider that should everyone (and this includes industrial users) start doing this, it will contaminate the ground water rapidly.
To put it another way - who are your nearest neighbors at this location? Would you want the used solutions entering their water source? Would you want *their* chemical wastes accidentally winding up in your water supply?
Can you hire a service to dispose of the solutions? That would be the safest approach I suspect. You could have a chem waste drain that went into a container that could be emptied periodically.
Jim
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ILLEGAL! :^) EPA calls this waste processing and you need all sorts of licensing and crap... 'course, it's probably only so for commercial enterprises.
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

||Hi. I just bought a house in the woods. The garage is a separate ||building, and I intend to set up a small metalworking shop to augment ||my woodworking -- I just graduated from school where I fell in love ||with metalsmithing while being a furniture major ... I especially love ||making small vessels & objects. The main problem is that there's no ||running water in the space, and no drainage pipes leading to my septic ||tank. ||Without spending a lot of $$, I figure I can set up a sink and feed it ||with a gardening ho se -- I can do this easily right outside the ||garage's back door.
Look into rainwater catchment. A standard gutter, leading to a tank, feeding the sink. Filters as needed. Unless you are in a desert, you can get all the water you need from the sky, for free. And for your uses, pure rainwater may be better, chemically. Texas Parts Guy

Peter gave you good advise. Do not dispose of pickle liquor or lubricants into your septic system or greywater system. By any state's laws (dictated by EPA) these are considered a hazardous waste and you can get in trouble that way. You could also ruin your septic system and contaminate your soil. Rinse water does not have the same concentrations and should not cause as much of a problem if you were attached to a municipal system, but since you have a septic system I would follow the advise and evaporate it. Most communities have household hazardous waste disposal and recycling events (also dictated by the EPA's new stormwater regulations) these would be ideal for any hobbyist to use (as I do). The following link should help you find a nearby site: . Liz

I don't think that neutralizing with baking soda is going to be of any real help. Silver compounds kill bacteria. Copper sulphate is a poison. And I think nickle is also one of the " bad " metals too. So neutralizing the acid isn't going to help much if any.
Someone please step in here. I think Clorox will turn the silver into silver chloride which if I remember correctly will precipatate and can be filtered out probably with paper towels. Someone here will surely correct me and come up with the best solution.
You really want to turn the metals into something you can filter out and dispose of as a solid.
Dan
snipped-for-privacy@veduta.com (lisau) wrote in message

Heh... So speaks someone whose words make it quite obvious that he's never been in northern California for anything more than a short visit. Basically, starting sometime in about April or May, and running through about October or November, it essentially doesn't rain. Basically nothing but the *VERY* occasional "storm" that dumps just about enough water to put dots in the dust on the windshield, and maybe make the little "petrified splash" marks in the dust of the driveway. Of course, that leaves the "wet season", when nobody around these parts is likely to argue with the statement that it rains buckets three days out of seven, and for most of the rest, it drizzles pretty much constantly, for weeks on end. Sure, there's plenty of water then, no question. But unless you're ready, willing, and able to create a pond or small lake, it's just not practical to store enough water to last from the final rain of one wet season to the first rain of the next.
We're not REALLY a desert - It just seems that way during dry season.

Chlorox will turn AgNO3 into AgCl but Ag is only sparingly soluble in H2SO4 so there won't be much Silver at all in the used pickle. A good flocculant for pickle solution is the Alum you find on the grocers shelf. Pickle solution that has become slow to remove CuO from heated Sterling can be "revived" by placing a clean strip of Sterling into it along with another clean (degreased and rust free) strip of steel. The dissolved Cu will plate out onto the strip of Sterling. (Which, by the way, is why you never use Iron or Steel tools in the pickle pot.) After the Cu is removed add slowly, while stirring, 1 tablespoon of Alum to each quart of pickle solution. Let stand and cool and the Alum will have caused most of the small particles suspended in the solution to agglomerate and settle to the bottom of the container where they will stay as you pour off the solution itself. Then add either Marble chips or Limestone chips to the solution to neutralize the remaining acidity. An excess of either will not harm the "environment" except aesthetically ane not even then if you use them as garden soil ammendment.

Yup. The mountain snowpack is everything.

Silver, copper and nickel are easily stripped out of the wastewater by use of ionic resins. Depending on how much water you plan on using, it won't be too expensive to set up. The resin beds will have to be regenerated by a commercial firm to strip the accumulated metals out for disposal, but this doesn't have to be done too often depending on the concentrations in your waste stream. The water that has been pushed through the resin beds is clean enough of the metals to be disposed of in the spetic system.
Acids can be neutralized with various common items and then have the ph adjusted and then pumped to the resin beds to strip out the metals.
The quickest way to get all the info that you will need is to visit a plating shop in the area that does MilSpec work and talk with their waste treatment people.
It's worth the time and effort to do it right from the begining. Having designed and built these type treatment systems commercially a few years ago, I do still have a few contacts in the industry if you need them.
Craig C. snipped-for-privacy@ev1.net

Wow, thanks everyone for the info!
We're on a community water supply here, not quite independent ... but I'm actually not sure where the water originates. We do have neighbors down the hill, as well as many mature redwoods, so I agree that letting the used water leach down the hillside isn't an option. When I mentioned a second septic, I guess I was envisioning one that could be pumped out rather than filter through a leaching field like our current one does. I'm specifically thinking of a friend of mine who lives on a creek and has his septic drained every few months because he does a lot a ceramic work and lets dust go down the drain. This probably isn't worth the expense for my situation.
I guess the best thing is to let the water evaporate and then dispose of the solids, though we have to be mindful of standing water -- mosquitoes, West Nile virus, etc. Maybe it can be boiled down (outside) to hasten the process (I think I'm going to set up my soldering station outside under a shed roof anyway). But it sounds like the consensus here is that while etching & photo chemicals & pickle should be disposed of separately, the water used to wash off pickle could possibly be filtered in some way, or evaporated into a solid. I guess its actually good that I don't have running water in my studio because I would have to build some kind of by-pass on the sink anyway.
Its funny because in school no one even talked about this ... everything went right down the drain!! In the furniture department there was a bit more interest in using "green" materials and processes, but not in the metal department. This should really be changed. (BTW did anyone read that depressing article in Metalsmith about strip mining processes? It gives new meaning to the term "precious metal")
Also, thanks for the tip about using rainwater. I was going to set up some barrels eventually, but had planned on using the H2O for gardening. But you're right, our water here is actually very corrosive, and we have to have all copper pipes. I hadn't really though about the effects on the metal I work with.
Again, thanks so much for all the input. I'll let you know what I end up doing! Also, I'm glad to have found this board. SNAG is the one organization touted at our school, but I find their lack of support to the community to be really annoying ... by this I mean no posting of events, shows, etc in the magazine, and no discussion boards or means of communication through their website.
Cheers! Lisa U

You got that right... Snowpack's down? California's screwed. Especially southern cali, since so much of the snowpack is routed into the canals to feed the "Greater" L.A. desert.

Is'nt Chlorox a compound which liberates chlorine gas on contact with acid? Chlorine is dangerous! Not only will it damage lungs, it will rust anything in its neighnourhood that is rustable. I would use common salt to precipitate silver from a solution. To shift copper and nickel I would use washing soda, sodium carbonate, but the liquor you get after filtering the precipitated metal hydroxides and carbonates off in paper towels will still contain more of these metals than can make it drinkable, especially so if the starting liquor contains any ammonia.
G.H.Ireland

Yes and? One will note that such things are often found under your kitchen sink. Never mix chlorine bleach with cleaning ammonia, unless you have your NBC mask on. This does however work fairly well if you have a mouse or roach problem and you go on vacation for a couple of days......
This is NOT recommended if you live in an apartment or condo.....
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell

This can happen inadvertently as well. My aunt is one example, her husband had been into home-brewing, and he had cleaned a bunch of the air bubblers in chlorine bleach at their kitchen sink. Enough bleach was in the sink trap, that when she went to use ammonia for something, it evolved enough gas to sent her to the hospital briefly.
This is another reason why, in a lab, one should pour copious amounts of water down the drain when disposing of chemicals therein. Dilute, dilute, dilute....
Jim
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