Battery plant waste water treatment process

摘要

A process of treating industrial waste water contaminated with environmentally unacceptable amounts of sulfuric acid and heavy metals such as lead, copper or zinc is disclosed which permits lowering of the concentration of the contaminants to a level permitting discharge to the sewer. Waste water resulting from floor wash and spray washing of lead acid batteries prior to shipment from the manufacturing facility contains sufficient sulfuric acid to cause the pH to normally be at a level of about 2 along with heavy metal contaminants present in concentrations which require treatment for removal before the discharge water will meet EPA standards. The water to be treated is directed to a first reaction and settling vessel where calcium carbonate is added along with an oxidation medium such as air which also functions to stir the stored waste water. Sufficient calcium carbonate is added to bring the pH of the solution to a level of about 5 and at the same time react with the heavy metals present such as lead, copper or zinc. Calcium sulfate and respective heavy metal carbonates precipitate and settle to the bottom of the treatment zone where they may be readily removed. In a second treatment vessel, calcium hydroxide along with enough calcium carbonate to maintain an excess of carbonate ion are added to complete separation of the heavy metals. Final removal of precipitate from the solution is accomplished through a suitable filter.