Removal of iron and manganese ions from abandoned neutral or alkaline mine drainage via ozone oxidation and micro-sand filtration: a pilot-scale operation

Abstract

A B S T R A C TThe objective of this study was to evaluate the ozone oxidation of dissolved Fe and Mn ions in abandoned neutral or alkaline mine drainage (NAMD) and the subsequent micro-sand filtration by conducting a pilot-scale operation with several ozone doses in an ozone reactor. The effects of the hydraulic retention time on the ozone oxidation were also investigated. The pH values were either neutral or slightly alkaline and the average Fe and Mn concentrations in the abandoned NAMD were 25.5 and 2.06 mg/L, respectively. The experiment results indicated that six-hour ozone oxidation with an ozone dose of 24.0 g O 3 /h (i.e. initial ozone concentration: 3.53 mg O 3 /L) and subsequent micro-sand filtration could meet the drinking water quality standard (less than 0.3 mg/L) for both Fe and Mn in the micro-sand filter effluent. The hydraulic retention time of the ozone reactor at this ozone dose was 106 s, and the media of sand grains were between 0.4 and 0.7 mm in diameter. The total dissolved solids, alkalinity, and SO 2À 4 concentrations of the influents were virtually unchanged in this pilot-scale operation. However, the oxidation-reduction potential of about 18 mV in influents increased rather gradually in effluents, and was recorded in the range of 185-210 mV during ozone oxidation. The ozone oxidation and subsequent micro-sand filtration under the operating conditions, in this study, appear to be among the desirable alternatives for the effective removal of dissolved Fe and Mn in the form of metal precipitates during ozone oxidation. This alternative could prevent metal precipitates from settling at the bottom of local water channels by removing them before they are discharged into streams.

The microbial killing capacity of aqueous and gaseous ozone on different surfaces contaminated with dairy cattle manure

“…Additionally, because of the O 3 flux limitation, adhesion slows diffusion which negatively impacts bacterial killing dynamics [ 38 ]. On metal surfaces RF was lower than on plastic as the O 3 destruction rate increased due to increased surface-ozone reactivity as a result of the easily oxidized iron and manganese that are present [ 39 ]. Additionally, iron bacteria have a strong binding affinity for metals, even with galvanic coating, where some of these bacteria provide tolerance to the high zinc concentration environment results in limiting O 3 contact to microbes [ 40 ].…”

Biofilms in Full-Scale Drinking Water Ozone Contactors Contribute Viable Bacteria to Ozonated Water

“…Ozone, a strong oxidant, is widely used for water treatment as it inactivates microbial pathogens, decomposes natural organic matter (NOM), removes taste-, odor-, and color-causing compounds, , oxidizes inorganic contaminants, , and improves clarification and filtration by inducing formation of precipitates or through reducing the stabilizing effects of NOM . Wastewater treatment, drinking water treatment, and water reuse plants have increasingly been including ozonation in their treatment trains to achieve contaminant removal. − Ozone’s use has increased in some European countries for tertiary treatment of micropollutants in wastewater, in North America for drinking water treatment where ozone application followed by biofiltration has increased 10-fold from 1993 to 2013, and in several water scarce regions of the world where ozone combined with biofiltration has been explored as an alternative to reverse osmosis for direct or indirect potable reuse (e.g., in Virginia, Australia, and California).…”

“…Ozone, a strong oxidant, is widely used for water treatment as it inactivates microbial pathogens, 1 decomposes natural organic matter (NOM), removes taste-, odor-, and color-causing compounds, 2,3 oxidizes inorganic contaminants, 4,5 and improves clarification and filtration by inducing formation of precipitates or through reducing the stabilizing effects of NOM. 6 Wastewater treatment, drinking water treatment, and water reuse plants have increasingly been including ozonation in their treatment trains to achieve contaminant removal.…”

Evaluation of the Decontamination Power of Aqueous and Gaseous Ozone on Various Contaminated Surfaces with Cattle Manure containing Salmonella

“…Furthermore, smooth surfaces decrease the adhesion of microbes to them making the microbes more vulnerable to O 3 [27]. The decrease in the RF on metal surfaces, compared to plastic might be due to increase the rate of O 3 destruction due to excessive surface-ozone reactivity as the iron, zinc and manganese are easily oxidized by O 3 [30].…”