Disposing of caustic soda?

Hey all, just filled a tub in the back yard with a caustic soda mix to clean up an old 2 stroke exhaust but it's just occurred to me that there will be approximately 3 or 4 gallons of caustic soda / rust mix to dispose of.

I am assuming I can dump it down the outside drain as caustic soda can actually be used to clean drains?

Reply to
Donnie
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Is the outside drain connected to a surface water sewer that goes to a local stream? The aquatic wildlife might not like that! If it connects to a foul sewer - OK.

Are you connected to a local foul sewer that goes to a sewage works? If so, then down the kitchen sink or a bog would be the best bet.

Reply to
Clot

Yep, sure can - be aware that any fat in the drain will turn to soap though, and swells about 50% in the process, so running some *hot* water through before and after could be a good idea if your drain's already a bit clogged?

On the subject of soda and cleaning steel, have you heard of the Bubbling Electric Gunge Tank method for removing rust? Big plastic tub, battery charger, half a cup of *washing* soda to each bucket of water, then connect the +ve from the charger to a piece of scrap iron, -ve to the piece to clean, leave for a few days - saves all that tiresome messing about with wire brushes, strong acids etc., and often does a good job of stripping paint too! (Google "electrolytic rust removal" for more details) The leftover liquid's drain-safe as long as you don't use stainless for the +ve electrode (which will eventually dissolve into the solution), stainless will make lots of hexavalent chromium in the solution, which is Very Bad Stuff.

Dave H.

Reply to
Dave H.

Depends what you mean by the outside drain. The ones in the street usually go straight into a watercourse, though some on busy roads go into big soak always to clean up the water a bit first. Car cleaning in the street can be bad news for local river life, and garages with car washes, were, on a survey I once did, the most common source of local river pollution - the next being people plumbing in foul waste to the surface water pipes by 'mistake'.

So best to check first and see where the waste goes when you flush the loo - or pour a bucket at a time down the loo.

The solution in your tub will gradually turn to sodium carbonate solution from contact with the air's CO2: this is 'washing soda', so what you would be doing by pouring it down the foul sewer would not be greatly different to doing a lot of washing. For other chemicals - like the chromium salts mentioned in another reply - pouring down *any* drain is generally a no no.

S
Reply to
Spamlet

Ohhh that hadnt crossed my mind, I guess the bog will be the best really then

Reply to
Donnie

It's not but I guess it never does any harm to pre flush the pipe just in case

I'd heard something like this before I must admit but never did give it a try, could be interesting to experiment with it.

Reply to
Donnie

yes. Or mix oil with it to form the sort of detergent the drains cope with every day.

With enough water in it, its not that evil a mix.

Reply to
The Natural Philosopher

You actually have to boil vegetable oil or animal fats with caustic for some time for specification. and it is not possible for mineral oils or paraffin waxes:

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testing oils, one key test of purity is its 'sap value'.

When oils are emulsified they are actually more polluting than when they are separated out from the water environment: the difference would be like you walking through a puddle of oil as opposed to having it sprayed at you in a mist that you could not avoid breathing in.

S
Reply to
Spamlet

Couldnt you freecycle it as caustic drain cleaner?

NT

Reply to
Tabby

heh

Reply to
Donnie

Grr just noticed what the spell checker has done! Saponification not 'specification' stupid dumb dictionary!

Reply to
Spamlet

Vegetable oils can be saponified (or personified, magnified, stratified, if your spell checker prefers :-)) at room temperature. Solids, such as wax, need to be heated, but only to their melting point. Beeswax e.g. can be emulsified (i.e. made virtually soluble in water) at

70 degsC with the mere hint of alkali, or completely saponified (and turned back into a solid) by adding more. Somewhere in between should be a water based wax polish.
Reply to
stuart noble

If it is an older house (pre ww2? it probably depends a lot, but it applied to our 1930's semi in Leeds) then you may well fin the foul water sewer and the rain water drain combined.

It's easy enough to check - open a manhole and watch to see if both foul water and rain water go down the same drain.

Reply to
chris French

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