Influence of Aquifer Heterogeneity on Cr(VI) Diffusion and Removal From Groundwater

Abstract

Previous studies show aquifer heterogeneity has an important influence on removal of Cr(VI) in groundwater, but little research has revealed the role of aquifer heterogeneity in Cr(VI) migration and how effective using emulsified vegetable oil is for Cr(VI) removal in groundwater. We simulated a laboratory sand-packed box over a 50-day period to research the effects of aquifer heterogeneity on Cr(VI) diffusion and also injected emulsified vegetable oil (EVO) into the permeable reactive barrier (PRB) filled with compost to investigate the influences of aquifer heterogeneity on Cr(VI) removal from groundwater, with fixed conditions of simulated true water temperature of shallow groundwater (19±0.5 ℃), hydraulic gradient (3‰), the Suzhou coal mining area (Anhui, China). The results show that aquifer heterogeneity had the significant impact on Cr(VI) diffusion with an overall diffusion direction of Cr(VI) that was from the upper left corner to the lower right corner along the direction of the groundwater; permeable reactive barrier would effectively remove Cr(VI) from groundwater in heterogeneous aquifer due to the vertical movement of microorganisms between different aqueous media; coarse sand and medium sand showed high performance in Cr(VI) diffusion, with a slight superiority to fine sand; following a one-time EVO injection, a considerably stable and uniform effective remove zone similar to the shape of ∑ was formed in the heterogeneous aquifer, and its Cr(VI) removal efficiency was over 95%.

Removal of Chromium Species by Adsorption: Fundamental Principles, Newly Developed Adsorbents and Future Perspectives

“…The Cr content has dramatically increased in recent years, for example, 6-12 ppb in the Godavari River in 2014 [4] and 10.5-113 ppb in the Yangtze River in 2009 [5] have been reported. The consistent diffusion of Cr(VI) into groundwater was also detected [6]. Undoubtedly, Cr species would have a great influence on the drinking-water quality and public health.…”