WATER TREATMENT

Abstract

The present invention relates to water treatment. In one embodiment there is provided a method of treating an aqueous system to inhibit growth of one or more micro-organisms therein and/or to reduce the number of live micro-organisms therein. The method comprises adding treatment agents to said aqueous system and wherein said treatment agents comprise: (a) a phosphonium compound; and (b) a halogen oxide compound.

Claims

1. A method of treating an aqueous system to inhibit growth of one or more micro-organisms therein and/or to reduce the number of live micro-organisms therein, wherein the method comprises adding treatment agents to said aqueous system which has a total dissolved solids (TDS) of 1000 mg l.sup.1 or greater and wherein said treatment agents comprise: (a) a phosphonium compound; and (b) a halogen oxide compound.

2. A method according to claim 1, wherein the halogen oxide compound (b) comprises chlorine dioxide.

3. A method according to claim 2, wherein, the method comprises treating an aqueous system wherein the content of chlorine dioxide is greater than 50% of the total halogen oxide compound(s) added to the aqueous system.

4. A method according to claim 1, wherein the phosphonium compound (b) comprises tri n-butyl n-tetradecyl phosphonium chloride (TTPC).

5. A method according to claim 1, wherein the method comprises treating an aqueous system to inhibit growth of facultative anaerobic bacteria and/or anaerobic bacteria and/or to reduce the number of live facultative anaerobic bacteria and/or anaerobic bacteria therein.

6. A method according to claim 1, wherein the method comprises treating an aqueous system having a total dissolved solids (TDS) of 10,000 mg l.sup.1 or greater.

7. A method according to claim 1, wherein the method comprises adding a phosphonium compound (a) to an aqueous system in an amount of at least 0.1 parts per million (ppm).

8. A method according to claim 1, wherein the method comprises adding halogen oxide compound (b) to an aqueous system such that it is present in an active residual amount of at least at least 0.05 parts per million (ppm).

9. A method according to claim 1, wherein the method comprises adding a phosphonium compound (a) and a halogen oxide compound (b) to an aqueous system in a weight ratio, expressed as active compound, of phosphonium compound:halogen oxide compound of from 1.0:50 to 100.0:1.0.

10. A method of treating an aqueous system to inhibit growth of one or more micro-organisms therein and/or to reduce the number of live micro-organisms therein, wherein the method comprises adding treatment agents to said aqueous system which has a total dissolved solids (TDS) of 1000 mg l.sup.1 or greater and wherein said treatment agents comprise: (i) tri n-butyl n-tetradecyl phosphonium chloride (TTPC); and (ii) chlorine dioxide.

11. A method according to claim 10, wherein method according to claim 1, wherein the method comprises treating an aqueous system having a total dissolved solids (TDS) of 1000 mg l.sup.1 or greater and wherein the method comprises adding TTPC to an aqueous system in an amount of at least 0.1 parts per million (ppm) and adding chlorine dioxide to an aqueous system such that it is present in an active residual amount of at least at least 0.05 parts per million (ppm).

12. A method according to claim 10, wherein the method comprises treating an aqueous system to inhibit growth of facultative anaerobic bacteria and/or anaerobic bacteria and/or to reduce the number of live facultative anaerobic bacteria and/or anaerobic bacteria therein.

13. An aqueous system incorporating a combination of: (a) a phosphonium compound; and (b) a halogen oxide compound.

14. An aqueous system according to claim 13, wherein compound (b) comprises chlorine dioxide.

15. A method of inhibiting or preventing the growth of one or more micro-organisms in an aqueous media, wherein the method comprises adding treatment agents to an aqueous media comprising dissolved solids such that it has a total dissolved solids (TDS) of 1000 mg l.sup.1 or greater and wherein said treatment agents comprise: (a) a phosphonium compound; and (b) a halogen oxide compound.

16. A method according to claim 15, wherein compound (b) comprises chlorine dioxide.

17. An aqueous media comprising dissolved solids and incorporating a combination of: (a) a phosphonium compound; and (b) a halogen oxide compound.

18. An aqueous media according to claim 17, wherein compound (b) comprises chlorine dioxide and wherein the aqueous media comprises greater than 10,000 mg l-1 total dissolved solids (TDS).

19. A biocidal composition comprising a combination of: (a) a phosphonium compound; and (b) a halogen oxide compound.

20. A biocidal composition according to claim 19 wherein compound (b) comprises chlorine dioxide.

21. A method according to claim 1, wherein the aqueous system contains oil.

22. A method according to claim 1, wherein the aqueous system comprises sodium chloride.

23. A method according to claim 1, wherein a complete kill of an anaerobe culture is obtained after a contact time of 10 minutes.

24. A method according to claim 1, wherein a complete kill of a facultative anaerobe culture is obtained after a contact time of 10 minutes.

Description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0194] The present invention will now be Illustrated by way of example with reference to the following preferred embodiments.

Examples

[0195] Aqueous systems were treated by adding treatment agents comprising: (a) a phosphonium compound and (b) a halogen oxide compound. The phosphonium compound (a) used was TTPC. The halogen oxide compound (b) was chlorine dioxide.

[0196] A suspension of Desulfovibrio vulgaris plus Enterobacter aerogenes bacteria containing from 110.sup.5 to 110.sup.6 cells/mL was prepared in sterile pH 8 phosphate buffer containing sodium chloride to give the desired total dissolved solids (TDS) concentration. Aliquots of this suspension were dosed with the indicated concentrations of the compounds (a) and (b) with the concentrations being measured as ppm by weight of the stated composition in the dosed suspension. The mixtures were allowed to stand at room temperature. At the designated contact times, each mixture was sampled to determine the total number of viable cells of both Desulfovibrio vulgaris and Enterobacter aerogenes by serial 10-fold dilution into API RP 38 media vials and anaerobic acid producing media vials, respectively. The vials were incubated at 37 C. for 72 hours. Results were recorded as log.sub.10 reduction in the viable count versus the control.

[0197] Aqueous media inoculated with anaerobe and aerobe culture and having a TDS of 30,000 mg l.sup.1 was treated with treatment agents comprising: (i) tri n-butyl n-tetradecyl phosphonium chloride (TTPC); (ii) chlorine dioxide; or (ill) a combination of TTPC and chlorine dioxide.

[0198] TTPC was used in the form of Bellacide 350, an aqueous composition of TTPC and water consisting of water and 50% by weight of TTPC available from BWA Water Additives.

[0199] Chlorine dioxide was used in the form of CDG Solution 3000 a 0.3% aqueous solution of chlorine dioxide available from CDG Environmental, LLC.

[0200] The efficacy of the treatment agents was evaluated by measuring the Log 10 Reduction of the anaerobic bacterium Desulfovibrio vulgaris and the facultative anaerobic bacterium Enterobacter aerogenes after contact times of 10 minutes, 30 minutes and 60 minutes as detailed in Table 1. For TTPC the stated ppm value relates to the amount of TTPC added (active). For the chlorine dioxide the stated ppm relates to the amount of free residual of chlorine dioxide.

TABLE-US-00001 TABLE 1 Treatment agent (ppm Log 10 Contact active) Log 10 Reduction TDS time Chlorine Reduction Facultative Example (mg l.sup.1) (minutes) TTPC Dioxide Anaerobes* Anaerobes* 1 30,000 10 3.125 0 0 2 30,000 10 6.25 0 0 3 30,000 10 0.25 3 3 4 30,000 10 0.5 4 6 5 30,000 10 3.125 0.25 5 6 6 30,000 10 6.25 0.25 5 6 7 30,000 30 3.125 0 0 8 30,000 30 6.25 2 1 9 30,000 30 0.25 3 3 10 30,000 30 0.5 5 6 11 30,000 30 3.125 0.25 5 6 12 30,000 30 6.25 0.25 5 6 13 30,000 60 3.125 0 0 14 30,000 60 6.25 5 1 15 30,000 60 0.25 3 3 16 30,000 60 0.5 5 6 17 30,000 60 3.125 0.25 5 6 18 30,000 60 6.25 0.25 5 6 *5 = complete kill for anaerobes *6 = complete kill for facultative anaerobes

[0201] The results show that chlorine dioxide is effective against anaerobes and aerobes alone with short contact times but surprisingly, despite TTPC being ineffective alone at short contact times, the combination of TTPC and chlorine dioxide was markedly more effective against aerobes and anaerobes than chlorine dioxide alone.

[0202] Accordingly, it will be appreciated that combining TTPC and chlorine dioxide may allow for less chlorine dioxide to be used to achieve complete kill of aerobes and anaerobes compared to chlorine dioxide alone.

[0203] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0204] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0205] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0206] The invention is not restricted to the details of the foregoing embodiment(s). The Invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.