Removal of Ammoniacal Nitrogen from Synthetic Wastewater Using Granular Activated Carbon and Limestone

Abstract

Background: Discharging high concentrations of nitrogen compounds in industrial effluent such as those from fertilizer manufacturing plants can cause various environmental problems like eutrophication. Objective: to investigate the efficacy of the granular activated carbon (GAC) and limestone (LS) as low cost media in removing ammonium ions from aqueous solution. Methods: Batch experiments were conducted to evaluate the efficacy of GAC and different ratios of GAC and LS mixture in the removal of ammoniacal nitrogen. The investigated parameters included contact time, initial ammonium ion concentration, pH, and amount of adsorbent. The adsorption isotherm and adsorption kinetic of ammonium ions by a mixture of GAC and limestone (LS) was studied Results: The experiments showed that the efficacy of GAC alone on the adsorption of NH4-N was 95% at shaking time 150 min, agitation speed 210rpm, temperature 22ºC and pH 9. The efficacy of a mixture ratio LS: GAC (30:20) on the removal of NH4-N was 75%. Conclusions: The study concluded that the removal percentage of ammoniacal nitrogen by a mixture of lime stone and GAC increase with the increase of agitation time and decrease with the increase of initial concentration while alkaline pH was more favorable for the adsorption of ammoniacal nitrogen.