Waste steel scrap was obtained from an industrial complex and washed with solvent in order to remove oil on the surface (ID). Waste steel scraps, acid-washed with a hydrochloric acid solution for 2, 5, 10, and 20 hours, were prepared through pretreatment (AD). Batch studies were subsequently run to test the reactivity of the waste steel scrap towards NO3^-(at 10 mg/L) and heavy metals (As and Cd, at 10 mg/L each), which are commonly present in leachate from landfill. Reactors were shaken on a reciprocating shaker (150 rpm, 25°C) and periodically analyzed for NO3- and heavy metals using IC and ICP, respectively.Waste steel scrap through pretreatment showed a high reactivity to remove nitrate. According to the results, AD should be pretreated for shorter to be a better reducing agent. Batch experiments suggest that waste steel scrap can effectively remove nitrate. The removal assays of heavy metals were also conducted in additional batch reactors to investigate the ability of AD to remove heavy metals. Based on adsorption results, significant heavy metals removal (As and Cd) was observed by AD. Laboratory experiments suggest that waste steel scrap can be recycled as reactive materials in a permeable reactive barrier (PRB) system to remove contaminants in leachate from landfill. This approach may also be practical and effective to treat other redox-sensitive groundwater pollutants, such as nitroaromatic compounds, chlorinated solvents, hexavalent uranium, and some pesticides.