Re: Uses of spent sulfuric acid

Of course, the best way to get rid of hazardous waste is not to generate it in the first place. There are less toxic alternatives to sulfuric acid pickle, but I am not convinced that they work as well. The second level in the hierarchy of waste minimization is to try and recover the spent acid. There are systems that recover spent acids, but they use even stronger acids to recharge the ion exchange resins. A smaller quantity of greater toxicity is a shallow victory at best. I agree that the most prudent solution is to develop recycling opportunities for the acid.

Waste acid pickle is regulated by the US EPA as a hazardous waste because of heavy metal contaminants that are commonly found in the spent solution. This narrows the possibilities somewhat because using in a manner that constitutes disposal (such as using the spent pickle solution as an amendment for alkaline soil) could earn you a semiprivate room at Club Fed.

There are waste exchange possibilities but, because of the numerous pitfalls that you may be exposed to (and personal liability), I would recommend that you ask a professional chemical engineer to help you with the waste exchange. I will be in Maryland in a few weeks along with 85 other environmental professionals. If your friend is not too far from Baltimore, this project may not cost more than a beverage or two.