WO2019109168A1 - Procédé pour le traitement des eaux de mine contaminée - Google Patents

Procédé pour le traitement des eaux de mine contaminée Download PDF

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Publication number
WO2019109168A1
WO2019109168A1 PCT/CA2018/051421 CA2018051421W WO2019109168A1 WO 2019109168 A1 WO2019109168 A1 WO 2019109168A1 CA 2018051421 W CA2018051421 W CA 2018051421W WO 2019109168 A1 WO2019109168 A1 WO 2019109168A1
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Prior art keywords
process according
aop
miw
ozone
water
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PCT/CA2018/051421
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English (en)
Inventor
Jose Alberto Gonzalez
Farid Vaezi Ghobaeiyeh
Douglas John Mckay
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Teck Resources Limited
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Priority claimed from CA2988187A external-priority patent/CA2988187C/fr
Priority claimed from US15/835,104 external-priority patent/US10947137B2/en
Application filed by Teck Resources Limited filed Critical Teck Resources Limited
Publication of WO2019109168A1 publication Critical patent/WO2019109168A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/70—Treatment of water, waste water, or sewage by reduction
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/722—Oxidation by peroxides
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/106—Selenium compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/18—Removal of treatment agents after treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/04—Aerobic processes using trickle filters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/32—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

  • the present application relates to the treatment of mine impacted water.
  • MIW Mine impacted water
  • Such water may include run-off water that has contacted waste rock dumps generated during mining of coal, copper, or zinc. Over time chemical and biological processes can become established within waste rock dumps, gradually releasing constituents of interest from the waste rock to the MIW.
  • Substantial removal of constituents of interest present in MIW can be done using physical-chemical or biological water treatment processes or a combination thereof depending on the constituents of interest to be removed.
  • MIW includes influent water to or effluent water from the aforementioned physical-chemical or biological water treatment processes, which can be active, semi-passive (e.g. saturated rock fills), or passive (e.g. wetlands) water treatment facilities in which key constituents of interest are substantially removed.
  • active e.g. saturated rock fills
  • passive e.g. wetlands
  • the least bioavailable form of soluble selenium in receiving environments is the selenate oxyanion in which selenium exists in the (+6) oxidation state.
  • the (+6) form of selenium is desirable because this form of soluble selenium is the least bioavailable.
  • PCT patent application publication WO 2013/041898 describes a method for removing trace organic and volatile selenium species present in drinking water. Some of these species were considered contributors to bad odour in the water. The described method includes adsorption of reduced selenium species on media containing oxides of either iron, aluminium, or titanium.
  • Reduced selenium species were largely adsorbed on the media and then partially removed from the media by passing ozonated water through the media.
  • PCT patent application publication WO 2009/005834 describes the introduction of ozone to the soil of a contaminated site followed by periodic addition of hydrogen peroxide to inhibit formation of hexavalent chromium within the soil.
  • PCT Patent application publication WO 2009117141 discloses a modular water treatment apparatus that utilizes side stream injection of ozone. The system utilizes ozone, with or without hydrogen peroxide, for disinfection or decontamination of the wastewater. The disinfected or decontaminated water is suitable for reuse.
  • PCT Patent application publication WO 2017070347 describes a method and system for decreasing the concentration of selenium species in water, particularly water containing difficult-to-remove selenium species.
  • Water containing selenium is first treated with potassium permanganate then treated in a two-step system comprising (a) a reactive solid containing zero-valent iron and iron oxide minerals in contact therewith and (b) ferrous iron.
  • a chemical oxidant is utilized to oxidize the reduced selenium species (mostly selenite) to selenate as a pre-treatment to a physical-chemical treatment process (in this case a zero-valent iron process).
  • potassium permanganate is the preferred oxidant. Hypochlorite is also utilized.
  • a process for treating MIW including one or more selenium species includes subjecting the MIW to an advanced oxidation process (AOP).
  • AOP advanced oxidation process
  • the process includes subjecting the MIW to an AOP including ultraviolet light and ozone or ozone and hydrogen peroxide to oxidize the one or more selenium species to selenate and thereby provide an AOP treated water. Residual oxidants are then removed from the AOP treated water.
  • the primary treatment objective of AOP is to oxidize selenium compounds present in MIW to selenate, thereby producing an AOP-treated water that decreases selenium bioavailability of the treated water. Residual oxidants left after AOP treatment (mainly ozone and hydrogen peroxide) are removed utilizing either chemical or physical-chemical means.
  • FIG. 1 is a simplified process flow diagram illustrating a process for treating MIW in accordance with an embodiment
  • FIG. 2 is a simplified process flow diagram illustrating a process for treating MIW in accordance with another embodiment.
  • the present application discloses a process for treating MIW that contains one or more selenium species.
  • the process includes subjecting the MIW to an advanced oxidation process (AOP) including ultraviolet light and ozone or ozone and hydrogen peroxide to oxidize the one or more selenium species to selenate and thereby provide an AOP treated water.
  • AOP advanced oxidation process
  • Residual oxidants are then removed from the AOP treated water.
  • MIW refers to water that has been impacted by a mining operation such as a coal, zinc, or copper mining operation.
  • Water soluble reduced selenium species present in MIW are those species in which selenium has an oxidation state less than (+6), including selenite ion, selenocyanate and selenosulfate ions, low-molecular weight semi- volatile species (e.g., dimethylselenide and dimethyldiselenide), and
  • organoselenium species such as dimethylselenoxide, methylseleninic acid and seleno-amino acids such as selenomethionine and selenocysteine.
  • selenium in the (+6) oxidation state is the least bioavailable form of dissolved selenium
  • WTF water treatment facility
  • the dissolved selenium concentration in MIW after a biological WTF may be lower than 20 pg/L, some of this selenium may be present in reduced oxidation states, often mostly in the (+4) oxidation state as selenite ion (SeCh 2 ), but with material amounts of organoselenium species.
  • Reduced selenium species present in MIW may be oxidized by an AOP.
  • the feed to AOP may be MIW at any state, that is as untreated water from waste rock dumps, or water after full or partial treatment to remove selenium in a WTF. Treating MIW at the end of a WTF process train with an AOP is desirable because the WTF process also decreases the total selenium concentration in the water discharged to the receiving environment.
  • MIW 102 is subjected to an AOP treatment at 104.
  • the AOP 104 is carried out in presence of ozone 206 generated in a commercially available ozone generator 208 that produces ozone gas from oxygen 205, at concentrations of 2% to 20% weight (the remainder is principally oxygen carrier gas).
  • the targeted transfer of ozone to water ranges from 3 mg/L to 25 mg/L.
  • Ozone transfer is achieved by injecting the oxygen-ozone gas mixture 206 into the MIW 102 utilizing a suitable commercially-available ozone injection system.
  • Ozone transfer efficiency (defined as the difference between feed gas and off-gas ozone concentrations divided by ozone concentration in feed gas) in commercial systems may be over 90%, and may be higher than 95%.
  • hydrogen peroxide 210 is added to the MIW to achieve a hydrogen peroxide concentration in the range from 1 to 25 mg/L.
  • Hydrogen peroxide is added to a target initial hydrogen peroxide to ozone transferred mass ratio of 0.2 to 2, preferably 0.4 to 0.7.
  • the AOP reactions then progress in single- or multi-stage commercially- available contactors to achieve a desired gas-liquid contact time.
  • the total contact time of the MIW 102 with ozone 206 and hydrogen peroxide 210 in the AOP treatment 104 may be 1 to 10 minutes and preferably 3 to 6 minutes.
  • the oxidation reaction of selenium species may be completed in less than 1 minute, and the remainder of the residence time in the contactors is utilized to separate and remove the excess gases (namely ozone and oxygen mixture) from water.
  • the released off-gases 211 after AOP treatment are captured and sent to an ozone destruct system 212 where ozone is converted to oxygen 215, which is then vented to atmosphere.
  • a fraction of the excess dissolved oxygen present in the AOP treated water (produced from decomposition of the injected ozone) is removed utilizing a suitable dissolved oxygen removal process 110, such as a water cascade system or a deaeration tank.
  • the dissolved oxygen concentration present in the AOP treated water may still be above its saturation level (up to 10 mg/L), after subjecting the water to the dissolved oxygen removal process 110. The presence of this excess dissolved oxygen does not appear to interfere with the subsequent quenching step 112 or 114.
  • stream 111 is treated in a quenching step 112 or 114. Quenching is utilized to remove residual ozone and hydrogen peroxide in the water to values below 10 pg/L and 0.5 mg/L, respectively, because both of these oxidants may be toxic to aquatic life at above these concentrations. Removal of residual oxidants by quenching to these target values is effective despite still having excess dissolved oxygen in the water.
  • Residual ozone in the water is not stable and may decay within tens of minutes. Hydrogen peroxide also decays over time but at much slower rates (tens of hours). Also, if residual hydrogen peroxide is present in stream 105, residual ozone may be less than 10 pg/L. In absence of hydrogen peroxide in steam 105, residual ozone concentrations may be higher than 10 pg/L.
  • Both residual ozone and hydrogen peroxide may be sufficiently removed in a quenching step utilizing a variety of methods, for example utilizing reducing agents such as sodium or potassium sulfite or thiosulfate salts, or utilizing granular activated carbon bed filters, or sand bed filters.
  • reducing agents such as sodium or potassium sulfite or thiosulfate salts
  • granular activated carbon bed filters or sand bed filters.
  • Residual oxidants may be removed by passing stream 111 through a granular activated carbon column 112 having an empty bed contact time (EBCT) of 2 to 10 minutes.
  • EBCT empty bed contact time
  • residual oxidants may be removed by sodium sulfite 114 utilizing, for example, 10 to 80 mg sodium sulfite per L of water.
  • Sodium sulfite dosage of 20 mg/L may be sufficient if residual hydrogen peroxide in stream 111 is less than 1 mg/L and residual ozone is less than 10 pg/L.
  • selenite concentration in the resulting AOP treated MIW 116 may be less than 2 pg/L, and may be less than 0.5 pg/L.
  • Other residual reduced selenium species may be present in MIW 116, at values close to or below analytical detection limits.
  • the AOP treated MIW 116 contains low concentrations of selenite ions and reduced selenium species. After equilibration with air (that brings the dissolved oxygen concentration to near its saturation value), MIW treated by the AOP system 116 may be further processed or discharged to the receiving environment.
  • the MIW 102 may be subjected to AOP treatment at 104 in presence of ultraviolet light (UV) 103 with continuous addition of ozone 206.
  • UV ultraviolet light
  • UV dosage may range from 1.4 to 2.4 Wh/L, with continuous addition of ozone resulting in applied ozone dosages of from 47 to 57 mg/L.
  • Fig. 2 The remaining processes indicated in Fig. 2 may be similar to those shown in FIG. 1 and described above.
  • utilizing UV no residual hydrogen peroxide is expected in stream 111 (since none was added).
  • some residual ozone may be present in this stream.
  • the residual ozone may be sufficiently removed to values below 10 pg/L using either the sodium sulfite quench 114 or the GAC quench 112 as described above.
  • the process described herein is applicable to the treatment of MIW under varying operating conditions (at various UV and ozone dosages, various ozone and hydrogen peroxide dosages, and contact times). These operating conditions may be adjusted depending on the MIW chemistry (e.g., total selenium concentrations, oxidation states of selenium species, alkalinity, total suspended solids, total dissolved solids, pH, water temperature, total and dissolved organic carbon, sulphate ion concentration, and concentrations of other organic and inorganic compounds). These variations may affect the oxidation of selenium species, but the proposed process is still suitable under varied conditions.
  • MIW chemistry e.g., total selenium concentrations, oxidation states of selenium species, alkalinity, total suspended solids, total dissolved solids, pH, water temperature, total and dissolved organic carbon, sulphate ion concentration, and concentrations of other organic and inorganic compounds.
  • the present processes may be added at any stage of a WTF to oxidize reduced selenium species to selenate.
  • the reagents used do not add deleterious compounds to the water being released to receiving environment, i.e., ozone and hydrogen peroxide decompose to oxygen and water and sodium sulfite is converted to sodium sulfate that already exists in the water.
  • the process may also oxidize residual nitrite to nitrate in MIW from a biological WTF.
  • Other advantages of the processes include short contact times, relatively low ozone and hydrogen peroxide additions, or low UV light exposure dosage in an advanced oxidation process to oxidize reduced selenium compounds to selenate.
  • Bench-scale tests were carried out to study the use of a chemical to oxidize or remove reduced selenium species in MIW (Method A) as a comparison to the processes illustrated in FIG. 1 and FIG. 2.
  • the tests were carried out utilizing beakers holding 1-L to 2.5-L water volumes and using reagent grade chemicals.
  • the chemicals included potassium permanganate, potassium persulfate, and hydrogen peroxide as oxidants and granular activated carbon as adsorbent. Agitation was carried out utilizing radial impellers at 150 RPM.
  • the tests were carried out at room temperature (17°C to 20°C) unless otherwise specified.
  • Bench-scale batch AOP tests were carried out to evaluate ozone and hydrogen peroxide dosages applicable to the process shown in FIG. 1, utilizing a glass reactor containing up to 2.5 L of MIW. Agitation was carried out using a magnetic stirrer. A mixture of oxygen and ozone gas was continuously sparged at the bottom of the reactor using a ceramic frit sparger. Ozone was generated by passing 99% Vol. oxygen gas through a bench-top corona discharge ozone generator (HG-1500 from Enaly). Hydrogen peroxide doses were added at preset times during the experiments. The ozone generation rate was approximated from equipment manufacturer data based on the oxygen gas flow rate and electrical power setting.
  • Ozone generation rate using 0.5 L/min (STP) of 99% Vol oxygen flow rate was constant at about 10 to 20 mg of ozone per minute. The produced ozone concentration was 2% to 5% Wt. and remaining was oxygen.
  • Treatment by AOP 104 (FIG. l) lasted from 5 min to 60 min. After treatment, samples were aerated for 10 to 30 minutes to remove oxygen super saturation. Residual hydrogen peroxide and ozone were removed with sodium sulfite as quenching reagent. Chemical assays and spectrophotometry analytical techniques were utilized to measure the residual ozone and hydrogen peroxide in AOP treated MIW.
  • Bench-scale AOP tests were carried out to evaluate UV light wavelength and dosages and ozone dosages applicable to the process illustrated in Fig. 2.
  • a bench-top UV unit (from ozone solutions UV-LAB-DE03) was used with either a 254 nm lamp (part GL287/4, with "L” glass) or a 185 nm lamp (part G8-9150, with "VH” glass).
  • the lamps had a nominal output power of 14 W at 380 mA current, and a diameter of 15 mm and a length of 287 mm.
  • the UV lamp was installed inside a cylindrical chamber with a working volume of water of 0.7 L. In some tests, two UV units were used in series to increase contact time.
  • the feed MIW was recirculated through one UV unit using a pump at a flow rate of 0.2 L/min (2-L total water treated) for a contact time of 12 min, corresponding to a UV dose of 1.4 Wh/L (Method C. l).
  • two UV units were connected in series, treating water at a flow rate of 0.2 L/min in a single pass treatment, corresponding to a UV dose of 2.4 Wh/L (Method C.2).
  • ozone was generated by passing 99% Vol. oxygen gas through a bench-top corona discharge ozone generator (HG-1500 from Enaly) as described above. The ozone gas was continuously injected in-line to the water fed to the UV units.
  • the ozone generation rate based on equipment manufacturer data using 0.5 L/min (STP) 99% Vol oxygen flow rate was constant at about 10 to 20 mg of ozone per minute.
  • the produced ozone concentration was 2% to 5% Wt. and the remaining was oxygen.
  • samples were aerated for 10 to 30 minutes to remove oxygen super saturation. Residual ozone was removed with sodium sulfite as quenching reagent.
  • Pilot-scale testing was also carried out for ozone- hydrogen peroxide AOP system, as shown in FIG. 1, utilizing a commercially- available AOP pilot unit for AOP 104 coupled to other equipment to carry out the dissolved oxygen removal 110, the sulfite quench 114, and the granular activated carbon quench 112.
  • the feed to the AOP pilot plant was MIW that was previously partially treated in a full-scale biological WTF.
  • the pilot plant feed water treatment rate was as high as 38 L/min.
  • Ozone-oxygen gas mixture was injected to the MIW using a venturi (side stream) system. Hydrogen peroxide was added to the water prior to or shortly after injection of ozone.
  • Ozone was generated by passing 88% Vol. oxygen through a pilot-scale corona discharge ozone generator at oxygen flow rate of 1.7-10.8 L/min (standard temperature and pressure), producing 0.1 to 1 g/min ozone.
  • the oxygen gas was produced from a pilot-scale pressure swing adsorption air separator unit. Produced ozone concentration in the gas phase was in the range 3-12 wt%, with the balance principally oxygen.
  • Transferred ozone dosage was calculated from ozone concentrations in the inlet gas (containing the ozone-oxygen gas mixture) and in the off-gas.
  • the off-gas streams from the contactors were collected and were treated using a catalytic ozone destruct unit to remove residual ozone before releasing the off-gas to atmosphere.
  • Oxygen super saturation from the AOP-treated MIW was removed in a cascade system within the vessel for dissolved oxygen removal 110 in FIG. 1.
  • Table 1 shows approximate MIW chemistry that may be treated utilizing the present method.
  • the assays indicated in the average column approximate the water chemistry utilized to carry out some of the experiments presented in the examples.
  • MIW with the range of water composition indicated by the minimum and maximum values Table 1 was tested.
  • feed MIW was spiked with reduced selenium species to test the performance of the AOP at higher selenium concentrations.
  • Nitrate-N mg-N/L ⁇ 0.005 18.3 0.014
  • Nitrite-N mg-N/L ⁇ 0.001 1.9 0.002
  • Se +4 is selenite ion
  • Se + 6 is selenate ion
  • SeMet is selenomethionine
  • MeSe is methylseleninic acid
  • DMetSeO is dimethyl selenoxide
  • SeCN is selenocyanate ion
  • SeSCh is selenosulphate ion
  • UnK represents the total concentration of any unidentified selenium-containing species detected by the speciation analytical technique
  • SeD is the concentration of selenium in all dissolved selenium species in the water (samples were filtered using a 0.45 pm filter prior to analysis);
  • SeT is the total concentration selenium in the water
  • SeTd is the sum of the concentrations of all the selenium species assayed by the ICP-CRC-MS speciation analytical technique. Note SeD can be different than SeTd as some selenium species may not be detected using selenium speciation analytical technique and because there are measurement uncertainties in both the speciation and total dissolved selenium assays causing analytical errors; Se+6R is the Selenate Ratio expressed as the ratio of the concentration of selenium in the (+6) oxidation state to the sum of the concentrations of selenium species (SeTd). The higher this value, higher the relative proportion of selenate in the water;
  • ORP mV
  • mV is the oxidation reduction potential of the solution at the end of the test (vs. Ag/AgCI);
  • HCI is hydrochloric acid
  • O3 is ozone
  • H 2 O 2 is hydrogen peroxide
  • UV lamps and the ozone generator were sufficiently run ("warmed up” for at least 15 min) prior to use to ensure stable operating conditions.
  • the applied ozone rate was constant at 9.5 mg/min. Ozone transfer efficiency was not measured as no off- gas ozone monitor was available. Ozone sparging lasted for 15 min, for a total applied ozone dosage of 57 mg/L treating 2.5 L of water. Hydrogen peroxide was dosed at 10 mg/L every 5 min starting one minute after continuous ozone sparging addition started (total hydrogen peroxide added was 30 mg/L). After 15 min of treatment utilizing ozone and hydrogen peroxide, MIW was aerated for 10 to 30 min by sparging air in the water and then samples were taken and prepared for analysis.
  • ozone was injected to the feed MIW at a rate of 9.5 mg/min prior to passing it through to the UV system. After 28 minutes of continuous treatment (to ensure steady state conditions), ozone addition and UV exposure were stopped. Treated water samples were collected over the last 7 min of treatment. Total applied ozone during the 7 min of treatment was 47.5 mg/L and applied UV dose was 2.4 Wh/L. The treated water were aerated for up to 30 minutes and then samples were taken and prepared for analysis.
  • Both feed MIW-2 and MIW-3 had more reduced selenium species than feed MIW-1, as indicated by the lower selenate ratio water values in feed MIW-2 and MIW-3 versus that of feed MIW-1, and the UV-ozone treatment may be less effective as a result.
  • the initial pH of the MIW was adjusted using hydrochloric acid, HCI.
  • the range of pH tested was 4.6 to 8.4.
  • feed MIW-4 and MIW-5 were spiked with reduced selenium species to assess the robustness of selenium oxidation using AOP.
  • the assay results for the spiked feed MIW samples are shown in Table 4.
  • Tests were carried out under similar conditions as those described in Example 2 using ozone and hydrogen peroxide (Method B). In these tests, ozone was added to the water at an applied rate of 9.5 mg of ozone per minute. Feed MIW volume was 1.5 L and temperature was 10 to 13°C.
  • Ozone addition continued for either 15 minutes or 60 minutes, as indicated in Table 4.
  • Hydrogen peroxide, if added, was dosed at 10 mg/L every 5 or 10 minutes after commencing the addition of ozone, as indicated in Table 4.
  • ozone addition was stopped and water was aerated for 10 to 30 minutes and then samples were taken for analysis.
  • TOC Total organic carbon
  • Tests were carried out at different pH (natural pH and pH-adjusted with HCI).
  • a single UV unit was utilized with a lamp at a wavelength of either 185 nm or 254 nm.
  • Water was recirculated through a single UV unit at a rate of 0.7 L/min from a beaker with 2 L total water volume into which ozone was continuously sparged (Method C. l). Water temperature was kept at 12 to 15°C.
  • Ozone was added at a rate of 9.5 mg/min to a total of 57 mg/L over 12 minutes of.
  • the total UV dose was 1.4 Wh/L.
  • ozone addition and UV exposure were stopped.
  • the water was aerated for up to 30 minutes and then samples were taken for analysis.
  • TOC Total organic carbon
  • Examples 1 to 4 indicate that AOP treatments with either ozone and hydrogen peroxide or UV and ozone can successfully oxidize reduced selenium species. However, these examples were conducted at a small bench scale and mostly batch mode in which important process parameters, including ozone transferred to the water, were not measured.
  • Example 5 illustrates the treatment of MIW from a biological WTF using ozone and hydrogen peroxide AOP and ozone only.
  • a pilot-scale AOP system was utilized to validate the success of AOP treatment at larger scale and continuous operating mode and to verify full-scale ozone transfer, contact time, and identify other process parameters.
  • Tests were carried out according to Method D and the process shown in FIG. 1 to test the ozone and hydrogen peroxide AOP at different operating conditions. Tests ran for several months at a temperature of 9°C to 11°C, at a water treatment rate of 38 L/min, a pH of 7.3 to 7.6, and a contact time of 4 minutes.
  • the pilot plant feed MIW composition was consistent with values listed in the "Average" column of Table 1.
  • the AOP system was operated at constant transferred ozone dosage.
  • the hydrogen peroxide dosing rate was adjusted to obtain 0.5-1 mg/L residual hydrogen peroxide in stream 105 of FIG. 1 after the AOP step 104.
  • the residual ozone concentration in stream 105 after the AOP step 104 was usually less than 10 pg/L, but was as high as 2 mg/L.
  • the measured dissolved oxygen in this stream was generally 30-40 mg/L.
  • Transferred ozone dosage was calculated from the ozone gas concentrations measured in the feed gas stream and in the off-gas streams and water flow rate.
  • SeTd was less that SeD assays for the feed MIW waters tested, indicating the presence of unaccounted reduced selenium species, which were not detected by the speciation analytical procedure.
  • the SeTd and SeD assays were within measurement uncertainty, indicating that most of the unaccounted selenium species were oxidized to species that were detectable by the analytical procedure.
  • Ozone alone was not effective at oxidizing all reduced selenium species to selenate.
  • Ozone and hydrogen peroxide AOP achieved the target selenate ratio (greater than 90%) at a relatively short contact time of four minutes in the AOP step.
  • AOP oxidized some of the insoluble selenium, indicated by smaller diffidence between SeT and SeD and the increase of the SeD after AOP than before.
  • MIW partially treated in a WTF was used in these tests.
  • the MIW had a significant level of background components (e.g., sulfate, carbonate, chloride ions and total suspended solids) that did not impair the AOP
  • Example 6 illustrates treatment of MIW from a biological WTF thaw was also spiked with additional constituents of interest using ozone and hydrogen peroxide AOP.
  • the pilot-scale AOP system of Example 5 was utilized to validate the success of AOP treatment at larger scale and continuous operating mode and to verify full-scale ozone transfer, contact time, and identify other process parameters.
  • Tests were carried out according to Method D and process shown in Fig. l to test the ozone and hydrogen peroxide AOP at higher concentrations constituents of interest. Tests ran for several days at a temperature of 9°C to 10°C, at a water treatment rate of 38 L/min, a pH of 7.5 to 8.0, and a contact time of 4 minutes.
  • the AOP system was evaluated at three transferred ozone dosages.
  • the hydrogen peroxide dosing rate was adjusted to obtain 0.5-1 mg/L residual hydrogen peroxide in stream 105 of FIG. 1 after the AOP step 104.
  • the residual ozone concentration in stream 105 after the AOP step 104 was usually less than 10 pg/L, but was as high as 2 mg/L.
  • the measured dissolved oxygen in this stream was in the range 34-50 mg/L.
  • Transferred ozone dosage was calculated from the ozone gas concentrations measured in the feed gas stream and in the off-gas streams and water flow rate.
  • a sodium sulfite dosage of 20 mg/L was found to be sufficient to achieve the target for the residual oxidants.
  • Samples of stream 116 were taken after sulfite quenching for selenium speciation.
  • AOP oxidized some of the insoluble selenium, indicated by the increase of the SeD after AOP than before.
  • MIW partially treated in a WTF and spiked with alkalinity, selenite, and chloride was used in these tests.

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)

Abstract

L'invention concerne un procédé de traitement des eaux de mine contaminée (MIW) contenant une ou plusieurs espèces de sélénium réduites par un processus d'oxydation avancé (POA) comprenant de l'ozone et de la lumière ultraviolette, ou de l'ozone et du peroxyde d'hydrogène. Le procédé oxyde une ou plusieurs espèces de sélénium réduites en sélénate et produit ainsi de l'eau traitée par POA. Les oxydants résiduels sont éliminés de l'eau traitée par POA.
PCT/CA2018/051421 2017-12-07 2018-11-09 Procédé pour le traitement des eaux de mine contaminée WO2019109168A1 (fr)

Applications Claiming Priority (4)

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CA2988187A CA2988187C (fr) 2017-12-07 2017-12-07 Procede de traitement de l'eau touchee par l'exploitation miniere
US15/835,104 2017-12-07
CA2,988,187 2017-12-07
US15/835,104 US10947137B2 (en) 2017-12-07 2017-12-07 Process for treatment of mine impacted water

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CN110339205A (zh) * 2019-08-19 2019-10-18 山东德信生物科技有限公司 富氢水组合物在抑制六价铬诱导的df-1细胞内质网应激及自噬中的应用

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US5200082A (en) * 1991-07-02 1993-04-06 Santina Water Company Method for removing toxic substances from industrial and agricultural waste water
US20030132166A1 (en) * 2002-01-15 2003-07-17 Paul Rey Method of treating mine drainage
WO2006116421A1 (fr) * 2005-04-25 2006-11-02 The Regents Of The University Of California Compositions et procedes pour eliminer l'arsenic dans l'eau
US7270728B2 (en) * 2002-08-19 2007-09-18 National Research Council Of Canada Photochemical transformation of metallic and non-metallic ions in an aqueous environment
WO2013016775A1 (fr) * 2011-08-03 2013-02-07 Green Shadows Commercial Pty Ltd Procédé de traitement de déchets industriels
US20150013987A1 (en) * 2013-07-11 2015-01-15 Baker Hughes Incorporated Method for reducing sulfide in oilfield waste water and making treated water

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US5200082A (en) * 1991-07-02 1993-04-06 Santina Water Company Method for removing toxic substances from industrial and agricultural waste water
US20030132166A1 (en) * 2002-01-15 2003-07-17 Paul Rey Method of treating mine drainage
US7115201B2 (en) * 2002-01-15 2006-10-03 Kroff Chemical Company, Inc. Method of treating mine drainage
US7270728B2 (en) * 2002-08-19 2007-09-18 National Research Council Of Canada Photochemical transformation of metallic and non-metallic ions in an aqueous environment
WO2006116421A1 (fr) * 2005-04-25 2006-11-02 The Regents Of The University Of California Compositions et procedes pour eliminer l'arsenic dans l'eau
WO2013016775A1 (fr) * 2011-08-03 2013-02-07 Green Shadows Commercial Pty Ltd Procédé de traitement de déchets industriels
US20150013987A1 (en) * 2013-07-11 2015-01-15 Baker Hughes Incorporated Method for reducing sulfide in oilfield waste water and making treated water

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110339205A (zh) * 2019-08-19 2019-10-18 山东德信生物科技有限公司 富氢水组合物在抑制六价铬诱导的df-1细胞内质网应激及自噬中的应用
CN110339205B (zh) * 2019-08-19 2021-08-24 山东德信生物科技有限公司 富氢水组合物在抑制六价铬诱导的df-1细胞内质网应激及自噬中的应用

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