Anodising legalities

[magicniner]

Before disposal you will need to neutralize the waste to PH7 using an alkali which results in non-toxic chemicals, dilution is not usually acceptable as it's impossible for you to add enough water for it to make any difference once your effluent has mixed with all the other waste water feeding into the treatment system.
Water companies usually require initial application & approval followed by testing and logging of quantities with PH readings and occasional lab analysis to ensure that nothing which shouldn't be disposed of is going down the drain, they'll also usually advise if asked,

- Nick

(I've worked in food factories (sweets & jaffa cakes) where neutralization & dumping of acid waste with general waste water is fairly common and wrote the software to run the jam cleanup/neutralization/dumping system for a mini-jaffa cake production line.)

[Jonathan]

Given that you can buy concentrated (91%) sulphuric acid from B&Q, sold as drain cleaner, it's surely legal to pour that down the drain, especially when diluted? However I tend to agree that neutralizing it is a kinder idea.

I've used the drain cleaner for anodizing solution and it seems fine. You can also do some fun chemistry experiments with it...