Environmental Application of Nano-Technology for Treatment of Industrial Wastewater

Abstract

Liquid industrial waste which is disposed in water bodies is not only dangerous for aquatic life, but also for people consuming it and using that water for irrigation. Heavy metals like lead, mercury, cadmium, arsenic, tin, selenium etc. are classified among the major pollutants due to their harmful and toxic characteristics, which pertains to them being un- metabolizable by the human body. Heavy metals present a public health issue due to their alarming effects. There are many ways to eliminate the heavy and toxic metals from the water before it is released into the environment including iron extraction, chemical precipitation, membrane separation, surface complexation, adsorption and electrolysis. One of the most used techniques among these is adsorption in terms of being inexpensive, highly efficient, simple and still flexible. Adsorption technique (Carbon adsorbent) has been used in the present research. Samples of wastewater were collected from each of the three industries i:e Cement ,Steel and Leather Industry. The sample size from each is kept to roughly 4.5 liters, collected in three bottles of 1.5-liter capacity. Prototype adsorption unit is small portable setup developed for the treatment of wastewater. Prototype was primarily prepared by National Centre of Physics (NCP); For the present experiment, used Carbon adsorbent has been prepared by treating modified charcoal at nano level. Half of the quantity from each sample was collected and was deposited to PCRWR (Pakistan Council of Research in Water Resources) for atomic adsorption analysis, prior to adsorption and post adsorption, respectively. Highest removal percentage obtained was of Lead i:e 95.5% and lowest removal efficiency came out to be of Nickel i:e 52.17%. Almost half of the nickel content passed without being adsorbed. Overall heavy metals adsorption percentage for all 10 elements came out to be 76.562%. This percentage is fine enough to cause a valuable decrease in the detrimental effects caused through excessive heavy metals. Main purpose of this study was to inspect the efficacy of this lab-based prototype in removal of heavy metals from industrial waste up to a level that they remain un harmful to environment. Now once it has produced desired results, upscaling of this sample prototype into a wastewater treatment plant, to meet the requirements of high industrial discharge remains an immediate requirement. Production of adsorbent at mass scale as well as development of other supporting equipment/components would remain a demanding task.