The method of heavy metal extraction from sludge with acid treatment and heavy metal removal

摘要

PURPOSE: A method for extracting heavy metals from sludge using acid is provided, which is characterized in that wet sludge is reacted with acid and catalyst at elevated temperature and high pressure so that sludge filtrate is used as carbon sources in sewage treatment plant and sludge cake is used as soil conditioner or cover soil in landfill site. CONSTITUTION: Sludge (water content of 95% or less) and acid are reacted in a reactor at volume ratio of 1 : 0.21 to 1. And catalyst is injected for reaction promotion. Operation conditions of the reactor are as follows: room temperature to 380 deg.C, 0.1 to 20 atm, and 0.5 to 24 hours. Consequently organics of sludge is decomposed acidly, and heavy metal is extracted in the liquid phase. Acid used in the method is waste acid or hydrochloric acid of pH 2.0.