Author Options:

Is it safe to use the Phosphoric Acid Barrels from a large soda bottler to make a composter? Answered

These are barrels I got when I requested Soda Syrup Barrels, directly from the bottling plant.  They still contain a small amount of liquid.  The barrels are white and have a label that says CRI-1020787, Corrosive, 8, Phosphoric Acid Solution, UN 1805, along with a bar code. There is no mention of percentage on the label.  I assume they are food grade.  I need to know if they are safe to use to make a composter.  Please let me know, what you know.


Rinse and spray the rinse water on your garden for fertilizer.

Rinse and you'll be fine. Phosphate is not harmful to compost, but excessive acid isn't going to help.


.  Do a triple rinse and you will be good to go. Phosphoric acid is pretty soluble in water (548 g/100 mL), so a good double rinse will probably do the job.