TREATMENTS FOR PERSISTENT ORGANIC POLLUTANTS

Abstract

A blended composition when used for the removal of persistent organic pollutants persistent organic pollutants (POP) such as perfluorooctanesulfonate (PFOS) from water, the blended composition comprising Bauxsol and an additive wherein the additive is selected from activated carbon and an oxidizing agent. Also disclosed is a method of using the blended composition in the treatment of contaminated water.

Claims

1. A blended composition when used for the removal of persistent organic pollutants (POPs) from water, the blended composition comprising Bauxsol and activated carbon.

2. The blended composition of claim 1, wherein the POP is a fluoro surfactant.

3. The composition of claim 2, wherein the fluoro surfactant is selected from one or more of perfluorooctanesulfonic acid (PFOSA; conjugate base perfluorooctanesulfonate; PFOS) and perfluorooctanoate (PFOA).

4. The blended composition of claim 1, wherein the composition comprises about 1% to about 99% by dry weight of the Bauxsol and from about 99% to about 1% by weight of activated carbon; or 98% to about 50% by dry weight of the Bauxsol and from about 2% to about 50% by weight of activated carbon; or 95% to 70% by dry weight of the Bauxsol and from about 5% to about 30% by weight of activated carbon; or 90% to about 80% by dry weight of the Bauxsol and from about 10% to about 20% by weight of activated carbon.

5. The blended composition of claim 1, further comprising an oxidising agent.

6. A blended composition when used for the removal of persistent organic pollutants (POPs) from water, the composition comprising Bauxsol and an oxidising agent.

7. The blended composition of claim 6, wherein the POP is an insecticide.

8. The blended composition of claim 7, wherein the insecticide is selected from one or more of DDT (dichlorodiphenyltrichloroethane), Dichlorodiphenyldichloroethylene (DDE) and Chlorpyrifos.

9. The blended composition of claim 5, wherein the oxidising agent is selected from one or more of peroxides (Mg, Na, H), superoxides, permangenates, chromates, dichromates, hypochlorites, chlorites, chlorates, perchlorates, nitrates, persulfates, and ozone.

10. The blended composition of claim 5, wherein the composition comprises about 1% to about 99% by dry weight of the Bauxsol and from about 99% to about 1% by weight of oxidizing agent; or 98% to about 50% by dry weight of the Bauxsol and from about 2% to about 50% by weight of oxidizing agent; or 95% to 70% by dry weight of the Bauxsol and from about 5% to about 30% by weight of oxidizing agent; or 90% to about 80% by dry weight of the Bauxsol and from about 10% to about 20% by weight of oxidizing agent.

11. The blended composition of claim 5, wherein the oxidising agent is a solid.

12. The blended composition of claim 1, wherein the Bauxsol is activated Bauxsol.

13. The blended composition of claim 1, wherein the water is pore water of soils and sediments, wastewater from an industrial plants or ground water from a contaminated sites.

14. The blended composition of claim 1, wherein the composition is particulate.

15. The blended composition of claim 14, wherein the composition is pelletised.

16. The blended composition of claim 1, wherein the composition is brought into contact with a catalyst selected from H.sub.3PW.sub.12O.sub.40, TiO.sub.2, or zero-valent iron.

17. The blended composition of claim 16, wherein catalyst is present in the range of from about 1% to 99% by dry weight of the catalyst and from 99% to 1% by weight of POP sorbed Bauxsol/activated-carbon blend; or about 1% to about 50% by dry weight of the catalyst and from 99% to 50% by weight POP sorbed Bauxsol/activated-carbon blend; or about 1% to about 30% by dry weight of the catalyst and from 99% to 70% by weight POP sorbed Bauxsol/activated-carbon blend; or about 1% to about 20% by dry weight of the catalyst and from 99% to 80% by weight POP sorbed Bauxsol/activated-carbon blend.

18.-20. (canceled)

21. The blended composition of claim 5, wherein the water is pore water of soils and sediments, wastewater from an industrial plants, or ground water from a contaminated sites.

22. The blended composition of claim 5, wherein the composition is particulate.

23. The blended composition of claim 5, wherein the composition is brought into contact with a catalyst selected from H.sub.3PW.sub.12O.sub.40, TiO.sub.2, or zero-valent iron.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0079] Embodiments of the invention will now be described with reference to the accompanying drawings which are exemplary only and in which:

[0080] FIG. 1 is a graph showing the before and after results for a Bauxsol and oxidizing agent (O.sub.3) additions to a pesticide-enriched wastewater.

[0081] FIG. 2 is a graph showing the before and after results for a Bauxsol and oxidizing agent (O.sub.3) additions to a pesticide-enriched and metal enriched wastewater.

[0082] FIG. 3 shows an example of a counter-current design configurations to generate bed/columns of infinite length.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0083] Bauxsol is a substance capable of binding metals and neutralising acid. Bauxsol is a substance that may be selected from bauxite refinery residues, known as red mud. Bauxsol may be referred to as a neutralised bauxite refinery residue. Bauxsol can be untreated or have been at least partially reacted with calcium and/or magnesium ions so as to have a reaction pH when mixed with 5 times its weight of water, of less than 10.5; neutralised by addition of acid; neutralised by injection of carbon dioxide; neutralised by addition of other minerals (such as gypsum); neutralised with ferruginous residues from other mineral processing industries (for example the red mud produced during titanium refining, ferruginous soils, ferruginous rock material (such as the fines produced as a by-product of iron ore mining) or bauxite). The Bauxsol material can preferably be finely ground.

[0084] Preferably, the Bauxsol substance in the blend capable of binding metals and neutralising acid is red mud from bauxite refinery operations that has been at least partially reacted with calcium and/or magnesium ions so as to have a reaction pH, when mixed with 5 times its weight of water, of less than 10.5.

[0085] One method by which the Bauxsol may be prepared is by reacting red mud with calcium and/or magnesium ions as described in International Patent Application WO2004/046064, the contents of which are incorporated herein in their entirety. Another way in which Bauxsol may be prepared is by reaction of red mud with sufficient quantity of seawater to decrease the reaction pH of the red mud to less than 10.5. For example, it has been found that if an untreated red mud has a pH of about 13.5 and an alkalinity of about 20,000 mg/L, the addition of about 5 volumes of world average seawater will reduce the pH to between 9.0 and 9.5 and the alkalinity to about 300 mg/L.

[0086] As taught in International Patent Application No. WO2004/046064, a process for reacting red mud with calcium and/or magnesium ions may comprise mixing red mud with an aqueous treating solution containing a base amount and a treating amount of calcium ions and a base amount and a treating amount of magnesium ions, for a time sufficient to bring the reaction pH of the red mud, when one part by weight is mixed with 5 parts by weight of distilled or deionised water, to less than 10.5. The base amounts of calcium and magnesium ions are 8 millimoles and 12 millimoles, respectively, per litre of the total volume of the treating solution and the red mud; the treating amount of calcium ions is at least 25 millimoles per mole of total alkalinity of the red mud expressed as calcium carbonate equivalent alkalinity and the treating amount of magnesium ions is at least 400 millimoles per mole of total alkalinity of the red mud expressed as calcium carbonate equivalent alkalinity. Suitable sources of calcium or magnesium ions include any soluble or partially soluble salts of calcium or magnesium, such as the chlorides, sulfates or nitrates of calcium and magnesium.

[0087] A further method by which Bauxsol may be prepared comprises the steps of: [0088] (a) contacting the red mud with a water-soluble salt of an alkaline earth metal, typically calcium or magnesium or a mixture thereof, so as to reduce the pH and alkalinity of the red mud; and [0089] (b) contacting the red mud with an acid so as to reduce the pH of the red mud to less than 10.5.

[0090] Optionally, this method may further include the step of separating liquid phase from the red mud after step (a) and before step (b).

[0091] In step (a), the pH of the red mud can be reduced to in the range of from about 8.5 to about 10, alternatively to in the range of from about 8.5 to about 9.5, alternatively to in the range of from about 9 to about 10, alternatively to about 9.5 to about 10, preferably from about 9 to about 9.5.

[0092] In step (a), the total alkalinity, expressed as calcium carbonate alkalinity, of the red mud may be reduced to be in the range of about 200 mg/L to about 1000 mg/L, alternatively to the range of about 200 mg/L to about 900 mg/L, alternatively to the range of from about 200 mg/L to about 800 mg/L, alternatively to the range of from about 200 mg/L to about 700 mg/L, alternatively to the range of from about 200 mg/L to about 600 mg/L, alternatively to the range of from about 200 mg/L to about 500 mg/L, alternatively to the range of from about 200 mg/L to about 400 mg/L, alternatively to the range of from about 200 mg/L to about 300 mg/L, alternatively to the range of from about 300 mg/L to about 1000 mg/L, alternatively to the range of about 400 mg/L to about 1000 mg/L, alternatively to the range of about 500 mg/L to about 1000 mg/L, alternatively to the range of about 600 mg/L to about 1000 mg/L, alternatively to the range of from about 700 mg/L to about 1000 mg/L, alternatively to the range of about 800 mg/L to about 1000 mg/L, alternatively to the range of about 900 mg/L to about 1000 mg/L, preferably less than about 300 mg/L.

[0093] In step (b), the pH is typically reduced to less than about 9.5, preferably to less than about 9.0, and the total alkalinity, expressed as calcium carbonate equivalent alkalinity, is preferably reduced to less than about 200 mg/L.

[0094] As described in International Patent Application No WO2004/046064, Bauxsol is a dry red solid that consists of a complex mixture of minerals. The general composition of Bauxsol depends on the composition of the bauxite and operational procedures used at each refinery as well as by how the red mud is treated after production. Neutralisation, of the raw red mud from the bauxite refinery, is achieved when soluble Ca and Mg salts are added and convert soluble hydroxides and carbonates into low solubility mineral precipitates. This procedure lowers the basicity to a pH of about 9.0 and converts most of the soluble alkalinity into solid alkalinity. More specifically, hydroxyl ions in the red mud wastes are largely neutralised by reaction with magnesium in the seawater to form brucite [Mg.sub.3(OH).sub.6] and hydrotalcite [Mg6Al.sub.2CO.sub.3(OH).sub.16.4H.sub.2O], but some are also consumed in the precipitation of additional boehmite [AlOOH] and gibbsite [Al(OH).sub.3] and some reacts with calcium in the seawater to form hydrocalumite [Ca.sub.2Al(OH).sub.7.3H.sub.2O] and p-aluminohydrocalcite [CaAl.sub.2(CO.sub.3).sub.2(OH).sub.40.3H2O]. The average composition of the raw Bauxsol is iron oxy-hydroxide (hematite) 31.6%, aluminium oxy-hydroxides (gibbsite) 17.9%, sodalite 17.3%, quartz 6.8%, cancrinite 6.5%, titanium oxides (anatase) 4.9%, calcium-alumino-hydroxides and hydroxy-carbonates (e.g. hydrocalumite) 4.5%, magnesium-alumino-hydroxides and hydroxy-carbonates (e.g. hydrotalcite) 3.8% calcium carbonate 2.3% halite 2.7%, others (e.g. gypsum) 1.7%. The mineralogy of the Bauxsol material contains abundant Al, Fe, Mg, and Ca hydroxides and carbonates to provide either tobermorite gel constituents for the setting of concretes, or provide appropriate additives to induce early setting of the concrete. Conversely, increased gypsum content within Bauxsol can retard setting rates.

[0095] Bauxsol can have a high acid neutralising capacity (2.5-7.5 moles of acid per kg of Bauxsol) and a very high trace metal trapping capacity (greater than 1,000 milliequivalents of metal per kg of Bauxsol); Bauxsol can also have a high capacity to trap and bind phosphate and some other chemical species. Bauxsol can be produced in various forms to suit individual applications (e.g. slurries, powders, pellets, etc.) but all have a near-neutral soil reaction pH (less than 10.5 and more typically between 8.2 and 8.6) despite their high acid neutralising capacity. The soil reaction pH of Bauxsol is sufficiently close to neutral and its TCLP (Toxicity Characteristic Leaching Procedure) values are sufficiently low that it may be transported and used without the need to obtain special permits.

[0096] Activated Bauxsol

[0097] A process not described in the prior art is the activation of the Bauxsol using sulphuric acid. Activation was first described as a means of neutralising caustic red muds, but can be applied to Bauxsol to produce a solid material with a slightly acid surface chemistry, particularly useful in improving arsenic removals.

[0098] The details of preparing activated Bauxsol with the combined acid and heat treatment method are as follows from H. Gen-Fuhrman et al. Journal of Colloid and Interface Science 271 (2004) 313-320 315. The powder is refluxed in 20% HCl for 20 min and the liquor is precipitated with ammonia at pH8. The precipitate is filtered and washed with deionized water (DIW) three times to remove the soluble compounds. The residue is then dried at 110 C. overnight and calcined in air for 2 h at 500 C. Finally, the Bauxsol is again sieved through a 0.2-mm screen, and stored in a vacuum desiccator until used for the batch sorption experiments. Henceforth, the term activated Bauxsol (AB) is used for the powder produced using the combined acid and heat treatment method. Note that in the combined acid and heat treatment method, all soluble salts are removed, whereas Fe and Al are precipitated as their hydroxides and retained in the residues due to the ammonia precipitation.

[0099] A second activation method is only the acid treatment is applied as follows. The initial Bauxsol particles below 0.2-mm are refluxed in 20% HCl for 20 min. The acid slurry is then filtered and the residue washed with DIW to remove residual acid and soluble Fe and Al compounds. Finally, the residue is dried at 40 C., re-sieved through a 0.2-mm screen, and used for the experiments without further treatment. The surface area and the cation exchange capacity (CEC) of the prepared powders are determined using the BET-N2 and ammonium acetate (pH 7) methods are increased.

[0100] For the third method, ferric sulfate or aluminum sulfate can be added to Bauxsol and AB as a dry powder. This mixture is later added to the arsenate containing solution. The purpose of the addition of ferric sulfate or aluminum sulfate is to change the sign and/or magnitude of the charge on the surface of the adsorbent particles. The amount of ferric sulfate or aluminum sulfate added is calculated as the amount of ferric sulfate or aluminum sulfate having the same cationic charge as the CEC of the AB or Bauxsol.

[0101] Advantages

[0102] A particular benefit of using Bauxsol in the compositions and methods of the present invention can be that the soluble salt concentrations, especially sodium concentrations are substantially lower than those in untreated red mud. This effect can be particularly important where the salinity of treated waters to be discharged to environments that are sensitive to sodium or salinity increases, or where salinity of discharge waters to be used as irrigation waters may adversely affect plant growth, have a lower potential impact.

[0103] More importantly, a polymineralic system such as Bauxsol has many advantages of single mineral treatments for waters, soils, solid, and liquid industrial wastes. Where a mono-mineralic system is used in there is provided only a single mechanism, or action of pollutant removal. Hence, the range of physico-chemical conditions for pollutant removals are limited both in mechanism and conditions. Hence, for example, when using hydrated lime for the treatment of acid rock drainage, only hydroxide precipitation is possible as the removal mechanism where:

M.sup.2++2OH.sup..fwdarw.M(OH).sub.2, where M.sup.2+ is and divalent trace-metal.

[0104] However, most trace metals also form hydroxide complexes and have very narrow pH ranges where particular M(OH).sub.2 precipitates are stable. Consequently, at pH 5.5 Cu(OH).sub.2 is at a solubility minimum from hydroxide precipitation, but elements like Zn, and Mn remain highly soluble. But, at pH 8 where Zn is at a solubility minimum from hydroxide precipitation, Cu is remobilised as Cu(OH).sub.3.sup., and Mn has still not reached a solubility minimum. Thus, simple mono-mineralic systems are often highly selective in what can be bound, but also the effective treatment range such as pH.

[0105] Poly-mineralic pollutant treatment systems, such as Bauxsol, are far more effective in their treatment pollutants, because they offer multiple mechanisms of pollutant removal/treatment, and or when one mineral of the system is out of its effective treatment range (e.g., pH) other minerals in the system become active. For example, in the treatment of trace-metals with Bauxsol, there is a sequential preference of metal removal, but also of mineral selectivity for different metals. Metal removal preferences are, Pb>Cr>Fe>Cu>ZnNi>Cd>Co>Mn, whereas mineral preferences (current data are limited to 6 metals Cu, Zn, Ni, Cr, Co and Mn) shows that Mn has no mineral preference, but is rather an oxidative precipitation, Cu is preferentially bound to hematite and hydrotalcite, Zn to hematite and gibbsite, Ni preferentially binds to hydrotalcite, Cr to hematite and sodalite, and Co to hematite and sodalite. Consequently, blending of Bauxsol with other minerals, salts, and other materials can enhance, or improve the range or concentrations of species treated, and/or improve the range of physico-chemical conditions in which is can be used. The addition of a neutral bauxite refinery residue was considered in WO/2002/034673, the contents of which are incorporated by reference.

[0106] Generally, it is understood that for some blended compositions used to treat some pollutants, the effects of blending, may be synergistic. This means that the pollutant is removed at a far higher rate than either component can achieve by themselves when summed as parts. However, the reverse is also possible, in that the blending agent is antagonistic and decrease performance, which in such cases these blends are not generally utilised, unless pollutant exclusion is sought, which in some cases is highly desirable.

[0107] Furthermore, some pollutant removals by blends may be simply additive between the first component and the blending agent (additive) loadings, that is, the mixture is equivalent to the mass-loading sum between what can be loaded to the first component, and that loaded on the blending agent. In purely additive systems, this may potentially lead to a decrease in overall pollutant removal performance, but often the additive is used to control, generally but not limited to, physico-chemical aspects of the treatment system.

[0108] Moreover, with some blends, it is not possible to determine if the treatment result is synergistic or additive, because the pollutants are removed to below the detection limits of current instrumentation. In this case once the detection limit is breached, it is impossible to determine if it is only the blending agent that dominates the pollutant removal, or whether the first component is dominant, or whether both components of the blend are actively supporting each other. In such examples, the pollutant to be removed is either already at very low concentrations close to the detection limit, and/or the pollutants has a very high affinity to either the blending additive and/or the first component, and can be removed to below detection from substantially higher concentrations.

[0109] Consequently, the use and choice of additives to be used as blending agents with Bauxsol, the concentration of the blending agent, and the role of the blending agent are not simple choices, nor are they necessarily intuitive and/or obvious to someone skilled in the art of water treatment. As such the application of Bauxsol and or its blends in water treatments must be assessed on a case by case basis and although some general rules apply as to which blends are best suited, the physico-chemical, and chemical makeup of the water can lead to obtuse and counter-intuitive results.

[0110] The prior art on Bauxsol as describe does not cover and/or mention the use of Bauxsol in remediation of wastewaters containing POPS, nor the Blending of Bauxsol with activated carbon, or suitable oxidants, to enhance POP removal to Bauxsol products and/or blends. Nor does the prior art investigate or make claims on microbiological activity, photo-, or thermal destruction of organic materials (e.g., POPs).

[0111] Substantial literature may be found on the sorptive characteristics of individual minerals such as alumina, hematites, gibbsite, TiO2 towards POPs, however few if any of this literature considers using said minerals in combinations, in the complexity of the mineral assemblages shown by Bauxsol.

EXAMPLES

[0112] Embodiments of the invention will now be exemplified with reference to the following non-limiting examples.

Example 1

[0113] DDT (dichlorodiphenyltrichloroethane) is one of the most well-known synthetic insecticides used in the world. It is a chemical with a long, unique, and controversial history, but like the vast majority of insecticides is based on a chlorinated biphenyl structure, of which there are some 209 congers available from mono substituted 2-Chlorobiphenyl to the fully substituted 2,2,3,3,4,4,5,5,6,6-Decachlorobiphenyl. From the biphenyl-system ring hydrogens may also be substituted of additional short chained organic moieties such as ethane as in DDT and DDD (Dichlorodiphenyldichloroethane), or ethylene as in DDE (Dichlorodiphenyldichloroethylene). After WWII, DDT was made widely available for use as an agricultural insecticide, particularly in the control of the malaria mosquito and its production and use soon skyrocketed. In Australia, DDT was used extensively until 1980 as an insecticide in farming, particularly in control of cattle ticks.

[0114] Water contaminated with DDT was treated as follows: [0115] 1. A blend of 75% Bauxsol and 25% oxidising agent sodium persulfate (Na.sub.2SO.sub.5; a compound derived from the reaction of sodium hydroxide with Caro's acid) was prepared by (37.5 g dry Bauxsol and 12.5 g Sodium persulfate), placing these in a sealed container and agitating the contents until a uniform colour was obtained, indicating that the blend was fully homogenised and dispersed. The blend was used immediately after formation to prevent any long-term degradation of the oxidant. [0116] 2. Increments (0.1-0.5 g/L) of the blended composition were added to the treatment water. [0117] 3. The blend was agitated for about 15 minutes to endure through mixing. [0118] 4. A reaction/settling period (about 45 minutes) was allowed before adding the next increment of Bauxsol blend at 2. [0119] 5. The water was sampled to determine its suitability of discharge. [0120] 6. Once the DDT concentration fell below about 2.0 g/L, the water was decanted off after a settling period (8 hours). [0121] 7. The solids were removed for safe disposal.

[0122] As shown in FIG. 1, in a mixed pesticide-enriched wastewater, DDT was reduced from 99 g/L to <2.0 g/L using a combination of an oxidizing agent (O.sub.3) and Bauxsol.

[0123] In addition, this treatment successfully demonstrated reductions in the subsequent metabolites of DDT, Dichlorodiphenyldichloroethane (DDD) from 15.2 g/L to <0.5 g/L, and Dichlorodiphenyldichloroethylene (DDE) from 1.0 g/L to <0.5 g/L (FIG. 1); level of detection for pesticides was 0.5 g/L.

Example 2

[0124] Chlorpyrifos an organophosphate insecticide, often mixed with toxic trace elements (e Chlorpyrifos (O,O-Diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) an organophosphate insecticide, which was introduced by Dow chemicals in 1965 to control foliage- and soil-born insects, particularly on corn, almond citrus, bananas, and apples crops. Chlorpyrifos is often mixed with additional toxic trace elements (e.g., arsenic and zinc), to improve efficacy when used pesticide against resistant pests. A soil matrix contaminated with pesticides, was leached with a MgCl.sub.2 to form an extracted lixivium. Using a blend of chemical reagent additives, Bauxsol and oxidant (O.sub.3) these extracted lixiviums were treated.

[0125] Lixivium contaminated with Chlorpyrifos and heavy metals was treated as follows: [0126] 1. A blend of 70% acid washed sand and 30% Bauxsol were established as a filter bed, where the washed acid washed quartz sand increases the hydraulic conductivity of the filter, but plays no part in chemical removals. [0127] 2. Influent lixivium (60 L in total) was pumped at a rate of 2.7 L/hr through the sand filter that provided a filter residence time of 180 minutes with the Bauxsol. [0128] 3. Prior to lixivium waters contacting the Bauxsol filter, an oxidising agent comprising ozone (O.sub.3) was injected to the lixivium at a rate of 100 mL/L to initiate oxidation of the water, which continued as it passed through the Bauxsol and filter. [0129] 4. Once the lixivium had passed through the filter, the effluent lixivium, was collected and analysed for Chlorpyrifos, arsenic, and Zn; effluent lixivium had a pH of 8.11.

[0130] Results in FIG. 2 show that chlorpyrifos was reduced from 7,972 g/L to 6.4 g/L, arsenic from 0.13 mg/L to 0.002 mg/L, and zinc from 0.35 mg/L to <0.01 mg/L.

Example 3

[0131] Perfluorooctanesulfonic acid (PFOSA; conjugate base perfluorooctanesulfonate, PFOS) and perfluorooctanoate (PFOA) are anthropogenic fluorosurfactants and global pollutants, added to Annex B of the Stockholm Convention on Persistent Organic Pollutants in May 2009.

[0132] PFOS and PFOA concentrations have been detected in wildlife and are considered sufficiently high to affect animal health, and higher PFOS serum concentrations were found associated with increased risk of chronic kidney disease in the general US population. The C8F17 subunit of PFOS is hydrophobic and lipophobic, like other fluorocarbons, while the sulfonic acid/sulfonate group adds polarity. PFOS is an exceptionally stable compound in industrial applications and in the environment because of the effect of aggregate carbon-fluorine bonds. PFOS and PFOA are a fluorosurfactants that lower the water surface tension than that of other hydrocarbon surfactants and has been used extensively as a fire-fighting agent.

[0133] PFOS and PFOA contaminated waters were interacted with Activated carbon and Bauxsol and compared. The data showed that Bauxsol was capable of binding substantial PFOS and PFOA, but not as effectively as activated carbon, but that a simple blend of the Bauxsol and activated was possible, which would require a lower dose than each individually.

[0134] Method Used [0135] 1. Increments (0.1-0.5 g/L) of Bauxsol, and Activated carbon were added to individual 5-L samples of the contaminated treatment water; [0136] 2. The blend was agitated for about 15 minutes using a magnetic stirrer to ensure thorough mixing of the solids with the water, before agitation was removed. [0137] 3. A reaction/settling period (about 30 minutes) was allowed before adding the next increment of treatment solid; until a total 5 g/L of Bauxsol, and g/L of a 25:75 Activated Carbon were added. [0138] 4. The water was decanted off after a settling period (8 hours). [0139] 5. The solids were removed for safe disposal.

TABLE-US-00002 TABLE 2 PFOS and PFOA removal to an unblended Bauxsol compared with activated carbon. Activated Un-blended Storm Water Raw carbon Bauxsol Environmental water Treated water treated water Discharge Criteria Analyte (g/L) (g/L) (g/L) (g/L) PFOS 6.58 <0.01 3.76 0.3 PFOA 0.217 <0.01 0.15 0.3 Sum 9.57 <0.01 PFOAS

Example 4

[0140] 1. A blend of 75% Bauxsol and 25% of Activated Carbon blend was prepared by weighing the appropriate components (37.5 g dry Bauxsol and 12.5 g Activated Carbon), placing these in a sealed container and agitating the contents until a uniform colour was obtained, indicating that the blend was fully homogenised and dispersed. [0141] 2. Increments (0.1-0.5 g/L) of the blended Bauxsol, and Activated carbon were added to individual one-L samples of the contaminated treatment water. [0142] 3. The blend was agitated for about 15 minutes using a magnetic stirrer to ensure through mixing of the solids with the water, before agitation was removed. [0143] 4. A reaction/settling period (about 30 minutes) was allowed before adding the next increment of treatment solid as per step 2 above. [0144] 5. In total 5 g/L of Bauxsol, 2.5 g/L of activated carbon, and/or 5 g/L of a 25:75 Activated Carbon/Bauxsol blend were added to the individual treatment waters. The determined addition rates could be based on the results of Example 3 above; [0145] 6. The water was decanted off after a settling period (8 hours). [0146] 7. The solids were removed for safe disposal.

[0147] Table 3 shows Perfluoro-sulfonic acid, Perfluoro-acid, and Perfluoroelomer sulfonic acid conger removals from a contaminated water to the Bauxsol 5 g/L, Activated Carbon 2.5 g/L, and a 25% activated carbon 75% Bauxsol blend 5 g/L with 30 min mixing, settled over night, filtered sample 0.45 g.

[0148] The, data shows that the blend is better than either individual component at a higher treatment rate for several POP compounds (e.g., PFOS). However, for some pollutants there appears to be a simple additive process (e.g., PFPeA, PFHxA). Whereas, all remaining chemicals show an indeterminate mechanism because one or both components reduce the raw water concentration below detection, compared to the formulated blend (e.g., 6:2 FTS shows a high degree of affinity for both the Bauxsol mineralogy and the activated carbon), as explained in preceding text.

TABLE-US-00003 TABLE 3 the removal of pollutants from contaminated water 25% activated Activated Carbon: 75% Bauxsol Carbon Bauxsol Treated Treated Treated Raw Water Water Water Water concen- concen- concen- concen- tration tration tration tration Analyte g/L g/L g/L g/L Perfluorobutane 0.030 <0.002 <0.002 <0.002 sulfonic acid (PFBS) Perfluorohexane 0.599 0.020 <0.002 <0.002 sulfonic acid (PFHxS) Perfluorooctane 3.730 0.052 0.004 <0.002 sulfonic acid (PFOS) Perfluorobutanoic 0.002 <0.010 <0.010 <0.010 acid (PFBA) Perfluoropentanoic 1.720 0.025 0.012 0.010 acid (PFPeA) Perfluorohexanoic 0.897 0.013 0.003 <0.002 acid (PFHxA) Perfluoroheptanoic 0.652 0.011 <0.002 <0.002 acid (PFHpA) Perfluorooctanoic 0.700 <0.002 <0.002 <0.002 acid (PFOA) 4:2 Fluorotelomer 0.006 <0.005 <0.005 <0.005 sulfonic acid (4:2 FTS) 6:2 Fluorotelomer 6.460 0.018 <0.005 <0.005 sulfonic acid (6:2 FTS) 8:2 Fluorotelomer 0.038 <0.005 <0.005 <0.005 sulfonic acid (8:2 FTS) 10:2 Fluorotelomer 0.007 <0.005 <0.005 <0.005 sulfonic acid (10:2 FTS)

Example 5

[0149] A soil matrix contaminated with 3070 mg/kg perchloroethylene PCE, was leached with an ASLP (Australian Standard Leach Procedure, 1997), which is similar to the US TCLP test, to form an extracted lixivium with a PCE concentration 716 mg/L. Using a blend of chemical reagent additives, Bauxsol and oxidant (O.sub.3) these lixiviums were treated. In addition, the soil was also treated using a Bauxsol blend and leached again to determine if in-situ soil treatments can be achieved.

[0150] Method Used for PCE Contaminated Soil: [0151] 1. A blend of 70% Bauxsol and 25% oxidising agent sodium persulfate (Na.sub.2SO.sub.5; a compound derived from the reaction of sodium hydroxide with Caro's acid) and 5% hydrated lime (Ca(OH).sub.2) was prepared by (70 g dry Bauxsol and 25 g Sodium persulfate, and 5 g of hydrated lime), placing these in a sealed container and agitating the contents until a uniform colour was obtained, indicating that the blend was fully homogenised and dispersed. The blend was used immediately after formation to prevent any long-term degradation of the oxidant. [0152] 2. Soils contaminated with 3070 mg/kg PCE, were treated with the blend at a rate of 10% blend with 90% soil (100 g of Bauxsol blend and 900 g of contaminated soil), where the soil was mixed with the blend in a small mixer until a uniform soil colour developed indicating near homogeneity of the mix. [0153] 3. The soil was suspended at a rate of 1 part soil to 5 parts water to form a slurry. Suspension was maintained for about 15 minutes. [0154] 4. The soil suspension was allowed to settle and react for 48 hours, before the water was decanted. [0155] 5. The soil was allowed to dry, before being sub sampled and leached for total PCE, and ASLP mobile PCE. The post treatment lixivium samples were analysed for their PCE content.

TABLE-US-00004 TABLE 4 the reduction in Total and ASLP PCE available in the raw and treated soils, when treated in the above method. Total PCE NSW EPA Total Allowable Sample Allowable PCE ASLP concentration concen- concentration. concen- in the ASLP tration (CT2 solid waste) tration (CT2 solid waste) Sample mg/kg mg/kg mg/L mg/L Raw Soil 3070 25.2 716 0.7 Treated 3.4 25.2 <0.005 0.7 Soil

Example 6

[0156] The ASLP lixivium contaminated with PCE (as used in Example 5) from the contaminated soil was treated as if it was a contaminated water as follows: [0157] 1. A blend of 70% acid washed sand and 30% Bauxsol was established as a filter bed, where the washed acid washed quartz sand increases the hydraulic conductivity of the filter, but plays no part in chemical removals. [0158] 2. Influent lixivium (10 L in total) was pumped at a rate of 2.7 L/hr through the sand filter (700 mL in total volume) that provided a filter residence time of 18 minutes with the Bauxsol; [0159] 3. Prior to lixivium waters contacting the Bauxsol filter, ozone (O.sub.3) was injected to the lixivium at a rate of 100 mL/L to initiate oxidation of the water, which continued as it passed through the Bauxsol and filter;

[0160] Once the lixivium had passed through the filter, the effluent lixivium, was collected and analysed for PCE, effluent lixivium had a pH of 7.8.

TABLE-US-00005 TABLE 5 the contaminated lixivium PCE solution concentrations pre- and post-ozonation treatment with a Bauxsol filter. Lixivium PCE ANZECC (1999) Interim concentration Allowable concentration Sample g/L g/L Raw Lixivium 716,000 82 Treated Lixivium <5 5

Example 7

[0161] A waste water containing several pesticides including herbicides and insecticides was treated. The treatment method was very similar to that used as per Examples 1 and 2.

[0162] The treat method was that a waste water contaminated with Chlorpyrifos, DDT, Fenamphos, Prothiophos Dieldrin, Endrin, As, and Zn was treated in the following manner: [0163] 1. A blend of 85% Bauxsol 10% activated carbon and 5% oxidising agent sodium persulfate (Na.sub.2SO.sub.5; a compound derived from the reaction of sodium hydroxide with Caro's acid) was prepared by (42.5 g dry Bauxsol, 5 g of activated carbon and 2.5 g Sodium persulfate), placing these in a sealed container and agitating the contents until a uniform colour was obtained, indicating that the blend was fully homogenised and dispersed. The blend was used immediately after formation to prevent any long-term degradation of the oxidant. [0164] 2. Increments (0.1-0.2 g/L) of the blended composition were added to the treatment water (10 L). [0165] 3. The blend was agitated for about 15 minutes to ensure thorough mixing. [0166] 4. A reaction/settling period (about 45 minutes) was allowed before adding the next increment of Bauxsol blend at 2. [0167] 5. Once 2. g/L of the blend was added, the water was decanted off after a settling period (8 hours); [0168] 6. The solids were removed for safe disposal.

TABLE-US-00006 TABLE 6 the effect of the described blend on the removal of a mixed waste water containing both pesticides (insecticides and herbicides) and trace element Zn and As. ANZECC trigger value for 99% protection of Concentration Concentration aquatic ecosystems In waste water after treatment Contaminant g/L g/L g/L Arsenic 15 1790 <1 Zinc 50 415 6 Chlopyrophos 0.009 0.188 <0.005 DDT 0.0004 0.197 <0.001 Fenamphos 0.1 5.4 <0.05 Prothiophos 0.1 0.32 <0.05 Dieldrin 0.001 0.176 <0.001 Endrin 0.0008 0.174 <0.001

[0169] Standard Paragraphs

[0170] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0171] It is to be understood that in any document incorporated herein by reference, the present description will take preference if there is any information in the incorporated document that is contrary to information described in the present specification

[0172] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word comprise or variations such as comprises or comprising is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.