Flow Velocity Effects on Fe(III) Clogging during Managed Aquifer Recharge Using Urban Storm Water

Abstract

Storm water harvesting and storage has been employed for nearly a hundred years, and using storm water to recharge aquifers is one of the most important ways to relieve water scarcity in arid and semi-arid regions. However, it cannot be widely adopted because of clogging problems. The risk of chemical clogging is mostly associated with iron oxyhydroxide precipitation; anhydrous ferric oxide (HFO) clogging remains a problem in many wellfields. This paper investigates Fe(III) clogging levels at three flow velocities (Darcy velocities, 0.46, 1.62 and 4.55 m/d). The results indicate that clogging increases with flow velocity, and is mostly affected by the first 0-3 cm of the column. The highest water velocity caused full clogging in 35 h, whereas the lowest took 53 h to reach an stable 60% reduction in hydraulic conductivity. For the high flow velocity, over 90% of the HFO was deposited in the 0-1 cm section. In contrast, the lowest flow velocity deposited only 75% in this section. Fe(III) deposition was used as an approximation for Fe(OH) 3. High flow velocity may promote Fe(OH) 3 flocculent precipitate, thus increasing Fe(III) deposition. The main mechanism for a porous matrix interception of Fe(III) colloidal particles was surface filtration. Thus, the effects of deposition, clogging phenomena, and physicochemical mechanisms, are more significant at higher velocities.

Examining long-term variability in saturated hydraulic conductivity of sandy soils and its influencing factors

“…higher than the final one. Similar results were reported by (Du et al, 2018;Vanderzalm et al, 2020), when they permeated the sample with a solution containing Fe (III) or water with suspended solids.…”

“…For example, there has been extensive research on the variation of hydraulic conductivity in groundwater artificial recharge (Konikow et al, 2001;Mays & Hunt, 2005;Siriwardene et al, 2007;Song et al, 2020;Ye et al, 2019). Vanderzalm et al (2020) and Du et al (2018) subjected sandy samples to water permeation containing suspended solids and Fe (III) ions, respectively, for an extended period (40 days in the former case and seven days in the latter study), leading to observed fluctuations in Ks that demonstrate a prevalent declining pattern over time. These studies identified physical and biological clogging mechanisms as dominant factors for Ks variation.…”

Laws and Mechanism of the Fe (III) Clogging of Porous Media in Managed Aquifer Recharge

“…To quantify the mass of clogging material that was retained in the sand column, the infiltration medium was excavated at 1 cm intervals at the end of the experiments. The sand samples were immersed in hydrochloric acid and shaken vigorously to dissolve the Fe (III) clogging material [23]. The mass retained in the column, referred to as M(t), was estimated from the difference between the inlet and outlet Fe (III) concentrations:…”

Lessons from 10 Years of Experience with Australia’s Risk-Based Guidelines for Managed Aquifer Recharge

“…Concerning the advisory section of the Guidelines that addresses clogging in MAR, there have been many papers since 2009 that have better-defined clogging processes (e.g., [50][51][52][53]) that would enable refinements to the current general guidance. Such refinements could include approaches to mitigate and remediate clogging, such as where statutory approvals may be required.…”