Optimization of multiple fillers used for removal of water pollutants of large well near the river in northern China

Abstract

Abstract In this paper, chromium (Cr(VI)), chemical oxygen demand (COD), and ammonia nitrogen in synthetically polluted well water were treated in three columns packed with different fillers to compare treatment effects. The concentrations of Cr(VI), COD, and ammonia nitrogen were used to investigate processing efficiency and find the most efficient column and fillers. Several effective fillers were scanned by a scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) to discover the removing mechanism. Results showed No.1 column with iron powder, activated carbon, and artificial zeolite in series exerted the best ability to remove pollutants. Total removal rate of No.1 column for Cr(VI), COD, and ammonia nitrogen was 91.7%, 47.1%, and 81.6%, respectively. Iron powder removed 86.6% of Cr(VI), activated carbon removed 30.1% of COD, and artificial zeolite removed 66.9% of ammonia nitrogen. The ability of iron powder to remove Cr(VI) is attributed to the redox reaction between iron powder and Cr(VI). Removal of COD by activated carbon is based on the adsorption of activated carbon. Artificial zeolite contains a variety of cationic components and is capable of removing ammonia nitrogen from the water by ion exchange. The No.1 column process has higher reference values for the pretreatment of polluted well water in the towns of underdeveloped countries.