Ambient iron-mediated aeration (IMA) for water reuse

Abstract

Global water shortages caused by rapidly expanding population, escalating water consumption, and dwindling water reserves have rendered water reuse a strategically significant approach to meet current and future water demand. This study is the first to our knowledge to evaluate the technical feasibility of iron-mediated aeration (IMA), an innovative, potentially economical, holistic, oxidizing co-precipitation process operating at room temperature, atmospheric pressure, and neutral pH, for water reuse. In the IMA process, dissolved oxygen (O₂) was continuously activated by zero-valent iron (Fe⁰) to produce reactive oxygen species (ROS) at ambient pH, temperature, and pressure. Concurrently, iron sludge was generated as a result of iron corrosion. Bench-scale tests were conducted to study the performance of IMA for treatment of secondary effluent, natural surface water, and simulated contaminated water. The following removal efficiencies were achieved: 82.2% glyoxylic acid, ~100% formaldehyde as an oxidation product of glyoxylic acid, 94% of Ca²⁺ and associated alkalinity, 44% of chemical oxygen demand (COD), 26% of electrical conductivity (EC), 98% of di-n-butyl phthalate (DBP), 80% of 17β-estradiol (E2), 45% of total nitrogen (TN), 96% of total phosphorus (TP), 99.8% of total Cr, >90% of total Ni, 99% of color, 3.2 log removal of total coliform, and 2.4 log removal of E. Coli. Removal was attributed principally to chemical oxidation, precipitation, co-precipitation, coagulation, adsorption, and air stripping concurrently occurring during the IMA treatment. Results suggest that IMA is a promising treatment technology for water reuse.

Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

“…Fe 0 -based filters have been demonstrated as capable of removing/inactivating different types of biological and chemical pollutants from water [64][65][66][67][68][69][70][71][72]. The performance of individual filters depends on the Fe 0 type (intrinsic reactivity); Fe 0 particle size (mm, µm or nm scale); filter design (e.g., depth of the reactive layer, dimensions of the filter), type and concentration of complimentary material (e.g., Fe 0 /sand ratio); water composition (e.g., pH and presence of competing species); and operating conditions (e.g., water flow, temperature).…”

“…While SW is an extremely widely used and cheap material, some commercial forms of SW contain oil and grease from the manufacturing process that should first be washed (cleaned) before use [70,138,139]. In addition, a mild acid treatment may be necessary in order to remove any surface contamination including Fe III -bearing (hydr)oxide phases.…”

Oxidation of organic contaminants in water by iron-induced oxygen activation: A short review

“…Meanwhile, reactive oxidants produced by the nZVI/O2 and the Fe(II)/O2 systems have been reported to be capable of inactivating bacteria and viruses by disrupting cell membranes or capsid proteins [56,57]; in particular, viruses were found to be selectively vulnerable to Fe(IV). Multiple processes such as chemical oxidation and reduction, coagulation and precipitation, adsorption, air stripping, and disinfection concurrently occur during the ZVI/O2 treatment [58].…”

Emerging Enzyme-Based Technologies for Wastewater Treatment

“…For instance, for a contaminant that does not mix with the ground water but only floats on its surface, remediation treatments were employed to either guide the contaminant to an "aspiratory" reservoir (16) or skim the contaminant from the water using material-based sponges, i.e., polypropylene fiber fabric (17) and woolen felt (18). Other treatments and decontamination technologies rely on chemical scrubbing (19), adsorption (20)(21)(22), precipitation via electrolysis (23), and chemical precipitation (24). While effective, such methods either need frequent replacement of the active decontaminating agent or are relatively inefficient, time consuming and expensive.…”