TREATMENT OF LABORATORIES WASTES IN EDUCATIONAL INSTITUTIONS (Case Study: Faculties of Al-Fateh University)

Abstract

Not be considered remnants of laboratories working with a academic institutions and industrial (Schools - Institutes - Universities - factories) in the habitof the main sources of environmental pollution. Although these wastes contain hazardous substances harmful to the environment and are produced on a regular basis, and being discharged without treatment in the sewage networks. Laboratory applications in some labs of university faculties in Libya suffer from non-availability of practical procedures concerning environment protection based on proper bases. In such environments, lots of chemical substances are consumed periodically. Regarding the increasing size and quantity of these wastes with their different kinds and forms (gaseous – liquid – and solid) and as a result of the increasing numbers of experiments being administered in labs for the increasing numbers of students. Human industrial and urban waste water containing which Heavy metals, were discharged into sewage systems, caused a serious problem that is a major concern worldwide. Many experiments were designed focusing solely on learning objectives, and therefore many of them unnecessarily produce a considerable volume of polluted wastes including heavy metals that must be properly handled and disposed. Wastewater treatment in universities is facing new challenges as heavy metals removal becomes necessary due to the requirements of laws and regulations. Research Objectives The main objective of this work is to investigate the possibility of treating liquid waste generated from experiments of inorganic chemistry laboratory to remove heavy metals before discharging into public sewerage network.

Research Methodology The study begins with reviewing relevant research and studies. In the second stage of the study that covers the applied part and prepare syntheticsolution by spiking distilled water with different metal salts to achieve the desired metal concentration. All chemicals used were of analytical grade. The chemicals used are copper sulfate (CuSO4. 5H2O), lead nitrate Pb(NO3)2,cadmium chloride (CdCl2.H2O), potassium permanganate (KMnO4), nickel chloride (NiCl2.6H2O), cobalt Chloride (CoCl2), potassium chromate (K2CrO4), silver sulfate (AgSO4) and potassium aluminum sulfate K2Al2 (SO4)4. The solution was prepared by dissolving 1g ofeach metal salt in 6 liters of distilled water. All experiments were carried out in bench scale and this study was conducted in three different phases, phase I, phase II and phase III. In phase(I),experiments were conducted with single precipitating agents, sodium hydroxide, calcium hydroxide, sodium sulfide or calcium carbonate were added to the liquid waste at different pH values, and then allow it to settle. While sequential precipitation was performed in phase (II) where more than one precipitates agent used sequentially precipitation. In the sequential precipitation the pH of liquid waste was adjusted at different values using sodium hydroxide or calcium hydroxide then allow for settling then sodium sulfide or calcium carbonate was added to the settled water and then allowed to settle. The reduction of chromium precipitating was used in phase III 2 precipitates agents were used sodium sulfite is added to the synthetic solution and the pH is lowered to 3.0 or less using acid (typically sulfuric acid). This process converts chromium from the hexavalent form to the trivalent form. The trivalent form can be treated similar to other metals and the pH of Liquid waste was adjusted at different values using calcium hydroxide then allow for settling.