Mahmoud Rahmati - M.Sc. Chemical Engineering, AmirKabir University of Technology
Seyed Javad Hashemi - M.Sc. Safety & Technical Inspection Engineering, Abadan Institute of Technology, Petroleum University of Technology,Abadan, Iran,

The toxic metals must be effectively treated/removed from the wastewaters. If the wastewaters were discharged directly into natural waters, it will constitute a great risk for the aquatic ecosystem, whilst the direct discharge into the sewerage system may affect negatively the subsequent biological wastewater treatment. Zeolite is a naturally occurring crystalline aluminosilicate mineral consisting of a framework of tetrahedral molecules, linked with shared oxygen atoms. Zeolite has a large surface area and high cation exchange capacity (CEC), and provides an exchange complex that can absorb variably-sized ions, which promotes its use as a selective adsorbent for oil and gas pollutants, pesticides, and metals. In this article, three applied methods are introduced for using Zeolite in wastewater treatment. In the first part of this article, utilizing a pure and chamfered-edge zeolite prepared from coal fly ash to remove mixed heavy metal ions such as Cr3+, Cu2+, Zn2+, Ni2+ and Co2+ in water is described. Then, heavy metal adsorption by Zeolite-Portland cement mixture is described. The coal fly ash based adsorbents were effective in removing mixed heavy metal ions from aqueous solutions compared to the commercial zeolite. Finally Combination of a membrane bioreactor and an oyster-zeolite column as a new approach for wastewater treatment is introduced. In this study, the crushed oyster shell-zeolite (OZ) packed-bed adsorption column will be introduced for advanced nutrient removal from the permeate.

Zeolite; Activated carbon; Adsorption; Heavy metals; Membrane bioreactor (MBR); Tertiary treatment