RELATING TO WATER TREATMENT

Abstract

In one embodiment, a method treats 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 includes adding treatment agents to the aqueous system, where the treatment agents include a phosphonium compound and a stabilised halogen containing composition. In one embodiment, an aqueous system incorporates a combination of a phosphonium compound and a stabilising halogen containing composition.

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 and wherein said treatment agents comprise: (a) a phosphonium compound; and (b) a stabilised halogen containing composition.

2. A method according to claim 1, wherein the stabilised halogen containing composition (b) comprises a bromine containing composition.

3. A method according to claim 1, wherein the stabilised halogen containing composition (b) comprises bromosulfamate.

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

5. A method according to claim 1, wherein the stabilised halogen containing composition (b) comprises a stabiliser (c) and a halogen containing compound (d) and/or wherein the stabilised halogen containing composition (b) comprises a stabilised halogen containing compound (e).

6. A method according to claim 5, wherein the halogen containing compound (d) comprises sodium bromide and wherein the stabiliser comprises sulfamic acid and wherein the halogen containing compound (e) comprises bromosulfamate.

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

8. A 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.

9. A method according to claim 1, wherein the method comprises adding a phosphonium compound to said aqueous system in an amount of at least 0.1 ppm.

10. A method according to claim 1, wherein the method comprises adding the composition (b) to provide a treated aqueous system comprising halogen containing compound (d) and/or stabilised halogen containing compound (e) in an amount of at least 0.1 ppm.

11. A method according to claim 1, wherein the method comprises adding stabilised halogen containing composition (b) to said aqueous system in an amount of at least 10 ppm.

12. A method according to claim 1, wherein the method comprises adding a phosphonium compound (a) and a stabilised halogen containing composition (b) to an aqueous system in a weight ratio, expressed as active compound composition, respectively, of phosphonium compound:stabilised halogen containing composition of from 1.0:0.5 to 1.0:100.0.

13. A method according to claim 1, wherein said phosphonium compound comprises tri n-butyl n-tetradecyl phosphonium chloride (TTPC), and wherein said stabilised halogen containing composition comprises bromosulfamate.

14. A method according to claim 13, 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 said aqueous system in an amount of at least 0.1 ppm and adding bromosulfamate to said aqueous system in an amount of at least 0.1 ppm.

15. A method according to claim 13, wherein the method comprises treating an aqueous system to inhibit growth of facultative anaerobic bacteria and/or to reduce the number of live facultative anaerobic bacteria therein.

16. A method according to claim 1, wherein said phosphonium compound comprises tri n-butyl n-tetradecyl phosphonium chloride (TTPC), and wherein said stabilised halogen containing composition comprises stabilised sodium bromide.

17. A method of according to claim 1, wherein said phosphonium compound and said stabilised halogen containing composition are at a weight ratio, expressed as active compound composition, of from 1.0:5.0 to 1.0:50.0; and wherein the amount of phosphonium compound is from 1.0 to 20 parts by weight per one million parts by weight of said aqueous system (ppm) and the amount of stabilised halogen containing composition is from 10 ppm to 500 ppm.

18. An aqueous system incorporating a combination of: (a) a phosphonium compound; and (b) a stabilised halogen containing composition.

19. An aqueous system according to claim 18, wherein said aqueous system is an aqueous media further comprising dissolved solids.

20. An aqueous system according to claim 18, wherein said aqueous system is a biocidal composition.

21. 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 and wherein said treatment agents comprise: (a) a phosphonium compound; and (b) a stabilised halogen containing composition.

Description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0190] The present invention will now be illustrated by way of example with reference to the following preferred embodiments.

Examples

[0191] Aqueous systems were treated by adding treatment agents comprising: (a) a phosphonium compound and (b) a stabilised halogen containing composition. The phosphonium compound (a) used was TTPC. The stabilised halogen containing composition (b) was a stabilised bromine composition which comprised sodium bromide stabilised to give bromosulfamate.

[0192] A suspension of Desulfovibrio vulgaris plus Enterobacter aerogenes bacteria containing from 110.sup.6 to 110.sup.8 cells/mL was prepared in sterile pH 8 phosphate buffer containing varying levels of sodium chloride to give the desired total dissolved solids (TDS) concentration. Aliquots of this suspension were dosed with the indicated concentrations of the phosphonium compound (a) and stabilised halogen containing composition (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 cells per millilitre.

[0193] 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) stabilised halogen containing composition; (ii) tri n-butyl n-tetradecyl phosphonium chloride (TTPC) or (iii) a combination of stabilised halogen containing composition and TTPC.

[0194] 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.

[0195] The stabilised halogen containing composition comprised sodium bromide stabilised to give bromosulfamate and the composition used was BromMax 7.1 available from Enviro Tech Chemical Services, Inc. This composition comprises bromosulfamate produced by oxidising sodium bromide with trichloroisocyanuric acid to give hypobromous acid and stabilising the hypobromous acid using sulfamic acid to yield bromosulfamate. The activity of the composition is approximately 7.1 % as chlorine.

[0196] 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 1 hour, 4 hours and 24 hours as detailed in Table 1. For TTPC the stated ppm value relates to the amount of TTPC added (active). For the stabilised bromine composition, the stated ppm relates to the amount of BromMax 7.1 added (product).

TABLE-US-00001 TABLE 1 Treatment agent (ppm) Stabilized Log10 Contact TTPC bromine Log10 Reduction TDS time (as composition Reduction Facultative Example (mg I.sup.1) (hours) active) (as product) Anaerobes Anaerobes 1 (comparative) 30,000 1 6.25 3 1 2 (comparative) 30,000 1 12.5 6 4 3 (comparative) 30,000 1 105 4 1 4 (comparative) 30,000 1 210 5 5 5 (comparative) 30,000 1 315 6 8 6 30,000 1 3.125 105 6 1 7 30,000 1 6.25 105 6 1 8 30,000 1 12.5 105 6 5 9 (comparative) 30,000 4 6.25 6 5 10 (comparative) 30,000 4 12.5 6 5 11 (comparative) 30,000 4 105 5 1 12 (comparative) 30,000 4 210 6 5 13 (comparative) 30,000 4 315 6 8 14 30,000 4 3.125 105 6 5 15 30,000 4 6.25 105 6 7 16 30,000 4 12.5 105 6 8 17 (comparative) 30,000 24 6.25 6 5 18 (comparative) 30,000 24 12.5 6 8 19 (comparative) 30,000 24 105 6 2 20 (comparative) 30,000 24 210 6 5 21 (comparative) 30,000 24 315 6 8 22 30,000 24 3.125 105 6 8 23 30,000 24 6.25 105 6 8 24 30,000 24 12.5 105 6 8

[0197] A Log 10 reduction of 6 represents a complete kill for anaerobes and a Log 10 reduction of 8 represents a complete kill for facultative anaerobes.

[0198] It can be seen from the Examples that with a TDS of 30,000 mg l.sup.1 stabilised bromine shows some biocidel activity against anaerobes but the addition of TTPC surprisingly improved the performance with a 1-hour contact time. It can also be seen that although stabilised bromine has poor biocidel activity against facultative anaerobes the addition of TTPC greatly improves performance essentially providing complete kill at 24 hours.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] 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.