Removal of some Heavy Metals from Industrial Wastewater and Gray Water by using some Natural and Organic Materials
Authors: Hameed Dhiaa Zahim , Naser Kadhim Makki 
Published: November 2023

Abstract
A study was conducted for knowing the quantity and quality of heavy metal ions adsorbed on surfaces of treatment materials used in treatment of polluted water and to know the most efficient in removal process. Study included conducting two experiments, the first is laboratory, which is treatment of two polluted waters, namely industrial water and gray water, using four natural treatment materials as filters, which are activated Charcoal, Eichhornia crassipes plant powder, Ceratophyllum plant powder, and Arundo donax plant powder. It used poles made of polyethylene with a length of 100 cm and a diameter of 10 cm equipped with a tap from bottom, a layer of glass wool was placed at bottom, and then treatment materials were placed on top of it at a height of 50 cm. A piece of gauze cloth was placed over it for filtering polluted water from solids. Polluted water was passed after being filtered from top of column and left for 24 hours for equilibrium, then filtrate was collected from bottom of column. Second experiment, it is liberation experiment for heavy metals adsorbed on treated materials, where heavy metals were extracted by a 0.005M concentration of DTPA solution. This process was repeated five times for same treatment material and concentration of heavy metals adsorbed was measured each time. Results showed the following: 1-High concentrations of heavy metals, each of Lead, Cadmium, Zinc and Nickel in industrial water, where they reached 5.190, 0.043, 3.727 and 0.371 mg L-1, respectively, exceeding the limits allowed by World Food and Health Organization for each of Cadmium, Zinc and Nickel, while concentrations of Lead is within internationally permitted limits. As for the gray water, concentrations of Cadmium excelled the internationally permitted limits, while concentrations of Lead, Zinc and Nickel were within internationally permitted limits. 2-Concentration of Lead and Cadmium in all materials used in bioremediation, with exception of coal, exceeded internationally permitted limits in plants. Concentrations of Zinc and Nickel in all materials used in bioremediation did not exceed the internationally permitted limits, while coal did not record the presence of Zinc and Nickel because it is a porous, burned carbonaceous material. 3-Increasing amount of heavy metals liberated from various treatment materials through bioreclamation process in first three extractions, then it began to gradually decrease in fourth and fifth extractions. The different treatment materials varied in amount of heavy metals released, and they can be arranged as follows in terms of amount released of heavy metals: Eichhornia crassipes plant powder > Ceratophyllum plant powder > activated charcoal > Arundo donax plant powder. 4-Highest amount of heavy metals was released from materials used in industrial water, then gray water for Lead and Cadmium, while treatment materials used in industrial water and then gray water excelled in amount released for elements Zinc and Nickel.