Heavy metals removal from industrial wastewater using bio-adsorbent materials based on agricultural solid wastes through batch and continuous flow mechanisms

Abstract

The objectives of this study were to design a biological treatment unit using agricultural residues (rice husk, plum leaves, banana peels, and green bean peels) as agricultural solid waste-based bio-adsorbents for heavy metals removal from industrial wastewater at El-Menoufia Governorate, Egypt. A batch and continuous flow prototype treatment units were manufactured for industrial wastewater treatment in accordance with the types of heavy metals that exist in the industrial region. The findings of the batch flow mechanism demonstrated that chromium had the best removal efficiency (RECr) ranged from 96 % to 99.5 %, followed by REPb from 86.79 % to 95.90 %. The lowest RE was detected with retention time 15 min, while the highest RE values were recorded at 45 min. The continuous flow results using both the Maskoub cartridge, and the Pinpoint cartridge showed levels of lead that varied between 0.042 and 0.041 mg L−1, respectively, with a REPb ranged from 97.89 % to 97.94 %, respectively, while cadmium levels are 0.002 mg L−1 for both cartridges with a RECd of 99.42 %, chromium levels were recorded as 0.003 and 0.002 mg L−1, respectively, with a RECr of 8.99 % to 99.33 %. It was found that all heavy metals levels after treatment were lower than standards required by international organizations, which supports the research outcomes for the application of the treatment unit in many industries, in addition to the economic feasibility of applying these units, where the total costs does not exceed 1226.86 US$ y−1 for a treatment unit with a discharge 1 m3 h−1.