This is not strictly a garden and landscape design orientated question, but I thought Fu might want to have some input on it.
At work we currently have some chemicals (potassium sulphate, magnesium sulphate, calcium nitrate, sulphate of ammonia) that we need to dispose of, at a guess about 10kg of each. Now my workplace (a government agency) doesn't have any protocols for disposing of this volume of these things (which I find appalling in itself), and the general consensus amongst people is 'just pour it on the garden', which I'm sure is not the most environmentally sound solution. Basically does anyone know how we would go about disposing of these chemicals appropriately?