what to do with radiator rinse water

I've got a scrap radiator that I will be using for a greenhouse heating application. The company I bought it from drained it but didn't rinse it. I'm going to rinse it out . . . what is the most environmentally friendly thing to do with the several gallons of water that result?

Is it practical to allow it to evaporate back down to a more concentrated solution, then take that to a chemical disposal facility at a landfill?

Now this is just my opinion... If it was already drained, then the amount of antifreeze left inside (in my opinion) is negligible.
I wouldn't rinse it next to the vegetable garden but...
I would and have just rinsed them out.  

A lot of it depends on what was in the radiator, and how much is left. Ethylene glycol breaks down rapidly in air, soil and water, and is pretty much gone within 28 days. You don't want it in you, or any other living thing, in the meantime, so I would pour it into some wood chips or biochar and spread those out somewhere to sit in the open for a few weeks. Other additives? Dunno.

To best answer that question at all levels both type of radiator and age come into play.  Basically it will break down into 3 answers.  You are actually dealing with 2 thing.  Metals and antifreeze.   The best answer is take it to a radiator shop and have it rinsed out.  Because they are capturing and flocking waste water this will be the least environmentally damaging.  Second best answer is above in dehydrate it down and then dispose of it at a dump.  Other options below and why.

Antifreeze is biodegradable toxic glick.   For the small amount in a drained radiator, if you can dilute it and put it in an organic pile not used for food stuffs and away from wells and over a couple of years it will degrade into safe compounds.  The big thing is to avoid concentrating it so it kills stuff before it degrades and that is why you dilute it and putting it on organic material both provides a mechanism for it to biodegrade while tying it up to reduce its mobility to reduce contamination.

Beyond that you are looking at metals

PTR(plastic tank radiator with aluminum core.  Mostly the metal is tied up by the antifreeze and by oxides.  Very little aluminum will make it out with the water and the one radiator worth is probably less than is already present in most soils so the risk is very minimal

copper brass newer from US.  Most radiators newer than about 10 years used lead free solider and it is also highly refined so there is minimal mercury so these.  Little or no metals risk from the tin and other metal of the solider.  The copper and zinc which are the other metals present are actually desirable trace elements.

copper brass older than 10 years or from outside the US can have lead solider.  It often has traces mercury too.  These are 2 metals you do not want in your soil.  Disposing of them is best done off sight properly.

As a radiator shop here is how I handle them.  They are washed and the wash water goes to the sump.  The water is settled and pumped to a treatment tank.  It is treated with a flocant that causes heavy metals to clump to it and settle out.  This actually chemically binds the heavy metals in place with the sludge.  This sludge and the sludge from the wash sump are then treated with an oil binder and are then mixed with low strength concrete in sealed buckets to twice physically encapsulate them beyond the chemical and thus treated my local dump will take them without it having to go to a hazardous waste site.

Thanks for the replies!  I was actually thinking about doing something with concrete to bind the stuff.

In any case, I have an aluminum/plastic radiator, so I shouldn't have to worry about the metals.

I'll probably put a little water into it, and pour that into a bucket for some kind of treatment, and then just rinse it out with enough water to dilute whatever is left.

What I wonder is, if you had an actively aerated compost extract brewing, I mean really teeming with life, could you slowly drip sufficiently diluted rinse water into it such that the bacteria might decompose it, or would this kill said bacteria in any iteration? I suppose I am wondering if there is any kind of microbiological habitat that could be captured and optimised for use as a bioreactor for breaking down such pollutants.

-CK

Chris Kott wrote:What I wonder is, if you had an actively aerated compost extract brewing, I mean really teeming with life, could you slowly drip sufficiently diluted rinse water into it such that the bacteria might decompose it, or would this kill said bacteria in any iteration? I suppose I am wondering if there is any kind of microbiological habitat that could be captured and optimised for use as a bioreactor for breaking down such pollutants.

-CK

You are beyond anything I have every seen information on.  I am going to guess the answer is yes.  Especially if it had sunlight exposure too.  As those will break down nearly any organic compound.  But I am only guessing.  I have over 2 decades of reading radiator magazines and looking at other information on properly handling that waste and I have never seen anything even close to what you are asking about.

Chris, I would think that if the concentration of the contaminant were low and the starting population of microbes sufficiently diverse, a community that lived off the stuff would develop over time. Maybe the concentration could be increased bit by bit. (Of course, I have NO experience with this field, but I've heard of such things being done.)

what kind of radiator is it, a car radiator or big cast iron one from a house?

It is a scraped car radiator; I'm trying to do this: https://permies.com/t/108087/car-radiator-heating-greenhouse-sizing