Use of Iron Nanoparticles for Post-Treatment of Metal Finishing Wastewater

Co-authors MATYSÍKOVÁ Jana, ŠKORVAN Ondřej, HOLBA Marek

Our research is targeted on treatment and post – treatment of metal finishing wastewater. This wastewater contains specific, hardly degradable pollutants, especially heavy metals and cyanides. Required outlet concentrations of these substances in the discharged stream are usually very low and difficult to reach. We have developed new treatment method using nanoscale zerovalent iron particles (nZVI) for heavy metal removal. nZVI is characterized by nanosize, high reactivity and large surface area. Because of a high reduction potential, nZVI is often applied for the remediation of wastewater or groundwater polluted by heavy metals. We started to apply nZVI for treatment of industrial wastewaters containing heavy metals based on those experiences. This environmentally friendly technology has great potential to combine redox processes with sorption and coagulation effect in one technological step. Reaction products are non-toxic iron compounds. The combination of more treatment effects enables removal of very resistant pollutants in cases where conventional technologies were not successful. Tests performed with pretreated metal finishing wastewater and nZVI revealed good efficiency of the removal of residual concentrations of nickel and copper. Pilot - scale reactor was designed for nZVI application, based on SBR (Sequential Batch Reactor) configuration. The system is not continuously operated and long reaction times can be set for required removal of pollutants. The reactor is equipped with the automatic control of the process phases and dosing of the nZVI under inert atmosphere. Testing and verification of the reactor on real wastewater is in the progress and the results will be presented.