U.S. patent application number 12/592699 was filed with the patent office on 2010-06-10 for wastewater treatment.
Invention is credited to John Hill, Joseph A. King.
Application Number | 20100140185 12/592699 |
Document ID | / |
Family ID | 42229568 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100140185 |
Kind Code |
A1 |
Hill; John ; et al. |
June 10, 2010 |
Wastewater treatment
Abstract
An antimicrobial method of treating wastewater and a wastewater
antimicrobial dispenser containing an antimicrobial agent for
treating a body of wastewater to kill microorganisms by increasing
the concentration metal ions therein. The antimicrobial method
includes the step of increasing the effectiveness of the biocidal
component in the body of wastewater to thereby lessen the need for
a supplemental biocide by adding a compound containing a hydantoin
ring where the compound containing a hydantoin ring may or may not
have any antimicrobial properties. The antimicrobial agent
including a source of biocidal metal ions and a compound containing
a hydantoin ring where the antimicrobial agent may be a powder, a
liquid a solid or combinations thereof.
Inventors: |
Hill; John; (Plymouth,
MN) ; King; Joseph A.; (Wayzata, MN) |
Correspondence
Address: |
Carl L. Johnson;Jacobson and Johnson
Suite 285, One West Water Street
St. Paul
MN
55107
US
|
Family ID: |
42229568 |
Appl. No.: |
12/592699 |
Filed: |
December 1, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61200958 |
Dec 5, 2008 |
|
|
|
Current U.S.
Class: |
210/755 ;
210/198.1; 210/753; 210/754; 210/764 |
Current CPC
Class: |
B01L 2300/0654 20130101;
C02F 2103/002 20130101; C02F 2201/002 20130101; B01L 2200/0636
20130101; C02F 2303/04 20130101; B01F 1/0027 20130101; C02F 1/505
20130101; C12M 47/02 20130101; C02F 1/688 20130101; A01N 59/16
20130101; G01N 15/1484 20130101; B01L 2400/0436 20130101; B01L
3/502761 20130101; C02F 1/76 20130101; G01N 2015/1486 20130101;
A01N 43/50 20130101; B01F 2001/0061 20130101; C02F 2103/008
20130101; G01N 15/1404 20130101; G01N 2015/149 20130101; B01L
3/502707 20130101; G01N 2015/142 20130101 |
Class at
Publication: |
210/755 ;
210/764; 210/753; 210/754; 210/198.1 |
International
Class: |
C02F 1/76 20060101
C02F001/76; C02F 1/68 20060101 C02F001/68 |
Claims
1. A method for treatment of wastewater containing solid pollutants
comprising: removal of the solid pollutants from the wastewater;
killing microorganisms in the wastewater after removal of the solid
pollutants by adding a biocidal component to a body of wastewater;
and enhancing the effectiveness of the biocidal component in the
wastewater by adding a compound containing a hydantoin ring to the
wastewater, which may or may not have any antimicrobial properties,
to thereby enhance the effectiveness of the biocidal component by
increasing the solubility of the biocidal component in the body of
wastewater.
2. The method of treatment of wastewater of claim 1 wherein the
step of adding a biocidal component to the body of wastewater
comprises adding a transition metal, a transition metal oxide, a
transition metal salt, or a combination thereof to the body of
wastewater.
3. The method of treatment of wastewater of claim 2 wherein the
step of adding the transition metal, the transition metal oxide,
the transition metal salt, or a combination thereof to the body of
wastewater comprises adding silver, silver oxide, silver salt, or a
combination thereof to the body of wastewater or a substrate that
has been coated or impregnated with metallic silver, silver salt,
or a combination thereof.
4. The method of treatment of wastewater of claim 1 wherein the
step of adding the biocidal component to the body of wastewater
comprises adding a silver-containing material, a silver alloy or a
silver nitrate to the body of wastewater and the compound
containing the hydantoin ring lacks biocidal effectiveness when
used alone
5. The method of treatment of wastewater of claim 1 wherein adding
the compound containing a hydantoin ring is a compound selected
from the group consisting of dimethylhydantoin (DMH)
Bromochlorodimethylhydantoin (BCDMH), Dichlorodimethylhydatoin
(DCDMH), Dibromodimethylhydantoin (DBDMH).
6. The method of treatment of waste water of claim 1 including the
step of placing a dispenser containing both the biocidal component
and the compound containing a hydantoin ring in the wastewater and
allowing the wastewater to come into contact with both the biocidal
component and the compound containing a hydantoin ring.
7. The method of treatment of waste water of claim 1 wherein step
of adding a compound containing a hydantoin ring includes adding a
concentration of 5,5-dimethylhydantoin to the body of wastewater to
obtain a final concentration of at least 5 ppm
5,5-dimethylhydantoin.
8. The method of treatment of wastewater of claim 1 wherein the
compound containing a hydantoin contains a halogen.
9. The method of treatment of claim 1 wherein the step of adding a
biocidal component to a body of wastewater comprises adding the
biocidal component to the wastewater after unwanted liquid
pollutants are removed from the wastewater.
10. A method of treating a body of wastewater to kill
microorganisms therein by increasing the effectiveness of an
antimicrobial agent comprising the steps of: adding a source of
biocidal metal to the body of wastewater to generate biocidal metal
ions in the body of wastewater; and adding a compound containing a
hydantoin ring to the body of wastewater, where the compound
containing a hydantoin ring may or may not have any antimicrobial
properties, to interact with the source of biocidal metal to
increase an availably of biocidal metal ions in the body of
wastewater.
11. The method of treatment of claim 10 wherein the wastewater is
greywater or ballast water.
12. The method of treatment of wastewater of claim 10 wherein the
source of biocidal metal ions comprises a source of silver ions and
the compound containing the hydantoin ring comprises
5,5-dimethylhydantoin and the level of 5,5-dimethylhydantoin in the
body of wastewater is at least 5 ppm.
13. The method of treatment of wastewater of claim 10 wherein the
step of adding the source of biocidal metal to the body of
wastewater comprises adding a source of metallic silver or metallic
silver alloy to the body of wastewater.
14. The method of treatment of wastewater of claim 12 including the
step of placing a dispenser containing both the source of biocidal
metal and the 5,5-dimethylhydantoin in the body of wastewater and
allowing wastewater to come into contact with both the source of
biocidal metal and the 5,5-dimethylhydantoin.
15. The method of treatment of wastewater of claim 11 wherein the
step of adding the source of biocidal metal to the body of
wastewater comprises adding silver chloride to the body of
wastewater.
16. A wastewater antimicrobial dispenser for killing microorganisms
in a body of wastewater comprising; a dispenser containing a source
of biocidal metal ions releasable into the body of wastewater to
generate a santizing level of biocidal metals insufficient to kill
the microorganisms in the body of wastewater and a compound
containing a hydantoin ring releasable into the body of wastewater
wherein the compound containing the hydantoin ring increases the
antimicrobial level of biocidal metal ions in the body of
wastewater to a biocidal level sufficient to kill microorganism in
the wastewater.
17. The wastewater antimicrobial dispenser of claim 16 including a
first housing having a water accessible compartment containing the
biocidal metal; and a second housing having a water accessible
compartment containing the compound containing a hydantoin
ring.
18. The wastewater antimicrobial dispenser of claim 16 wherein the
source of biocidal metal comprises silver chloride and the compound
containing a hydantoin ring comprises 5,5-di methyl hydantoin.
19. The wastewater antimicrobial dispenser of claim 16 wherein the
biocidal metal is selected from the group consisting of a metallic
silver alloy, pure silver or a substrate impregnated with metallic
silver and the compound containing the hydantoin ring is either
5,5-dimethylhydantoin (DMH) Bromochlorodimethylhydantoin (BCDMH) or
Dichlorodimethylhydatoin (DCDMH) or combinations thereof wherein
the compound containing the hydantoin ring is either a powder, a
liquid, a solid or combinations thereof.
20. The wastewater antimicrobial dispenser of claim 16 wherein the
compound containing a hydantoin ring lacks biocidal effectiveness
to kill microorganisms.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional
application 61/200,958 filed Dec. 12, 2008 titled Treatment of
Wastewater.
FIELD OF THE INVENTION
[0002] This invention relates generally to wastewater treatment
and, more specifically to treatment of wastewater to kill
microorganisms therein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
None
REFERENCE TO A MICROFICHE APPENDIX
None
BACKGROUND OF THE INVENTION
[0003] An increase in the consumption of water for all types of
uses as well as the quest for a cleaner environment generates a
need to recycle all types of water including wastewater.
Wastewater, which may be either residential or industrial
wastewater, may be in various conditions and may include human
waste, food scraps, oil, soaps and chemical. Household wastewater
generally comes from household appliances, bathtubs, showers and
toilets. Wastewater that is heavily polluted is often referred to
as black water and household wastewater that does not include
toilet waste is often referred to as greywater since, although
polluted, it generally contains lesser amounts of pollutants. An
example of a system for wastewater separation and wastewater
treatment in shown in U.S. Pat. No. 6,299,775. While biocidal
metals are effective in killing microorganisms one of the
difficulties with killing microorganisms in wastewater with
biocidal metals is that in the presence of wastewater the
solubility of the biocidal metal ions may not be sufficiently high
so as to effectively kill the microorganism in the wastewater.
[0004] Another type of wastewater is found in industrial
applications and industrial facilities where wastewater is used for
a variety of tasks including cooling, cooking, manufacturing and
other process that require the use of water that results in
contamination of the water and requires that the wastewater be
subject to an antimicrobial treatment before retuning the water to
the environment.
[0005] Still other types of wastewater include water, which is used
in the hold of ships for ballast. Conditions within the water
storage can not only pollute the water with solids but also can
cause growth of harmful microorganisms as well as transfer of
harmful microorganisms from one geographical location to another
geographical location as a ship picks up ballast water in one port
and discharges the ballast at another port or at sea. Before the
wastewater is discharged back into the sea or a reservoir the
harmful microorganisms in the water, which is used as ballast,
needs to be subjected to an antimicrobial treatment to kill the
harmful microorganisms before the water is discharged.
SUMMARY OF THE INVENTION
[0006] Briefly, the present invention comprises a method of killing
microorganisms in wastewater with biocidal metal ions by elevating
the concentration of available biocidal metal ions in the
wastewater addition by including of an additive to the wastewater,
which may or may not have any antimicrobial properties.
[0007] In one example the invention includes a dispenser with an
antimicrobial agent comprising a compound containing a hydantoin
ring and a biocidal metal ion source
[0008] In another example the invention includes method of killing
microbes in wastewater by adding a source of biocidal metal ions to
the body of wastewater together with a compound containing a
hydantoin ring to enhance the biocidal metal ion concentration to a
level effective to kill the microorganisms in the wastewater.
[0009] In another example the compound containing a hydantoin ring
may be tabletized, or be in liquid, powder or other solid form so
the compound containing the hydantoin ring can be placed in a body
of wastewater together with a source of biocidal metal ions to kill
microorganisms the wastewater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 discloses a system for treating wastewater;
[0011] FIG. 2 shows the concentrations of silver with and without
the addition of DMH
[0012] FIG. 3 shows an example of a one-chamber dispenser;
[0013] FIG. 4 shows an example of a two-chamber dispenser; and
[0014] FIG. 5 shows a schematic of a hydantoin ring.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] FIG. 1 discloses a wastewater treatment system 10 for
recycling wastewater to a state where the water is either fit for
human consumption, agricultural use or otherwise returned to the
environment. Wastewater, of all types which includes but is not
limited to residential wastewater, industrial wastewater,
commercial wastewater and reservoir wastewater comes in various
conditions and may include human waste, food scraps, oil, soaps and
chemical. Household wastewater generally comes from household
appliances, bathtubs, showers and toilets. Wastewater that is
heavily polluted is often referred to as black water and household
wastewater that does not include toilet waste is often referred to
as greywater since, although polluted, it generally contains lesser
amounts of pollutants.
[0016] Wastewater treatment system 10 includes a holding tank 11
that receives wastewater from an inlet pipe 12, In one application
the wastewater can be from commercial, industrial or households
septic systems and can be either greywater or blackwater. After
arriving in the holding tank 11 the wastewater is pumped to a water
treatment station 12 where solid or particle pollutants are removed
from the wastewater. Solids may be removed through various methods
including centrifuges or gravitation settling. The solid pollutants
are removed through outlet 12a and the wastewater with the solid
pollutants removed is then pumped through pipe 15 to another water
treatment station 14 where unwanted liquids such as oils or soaps
are removed from the wastewater and discharged through outlet 14a.
Smaller particles or unwanted liquids may be removed by filters or
the like. Once the unwanted liquids are removed from the wastewater
the wastewater is pumped to water purification station 16 through
pipe 17.
[0017] The amount and type of treatment of the wastewater in
purification chamber 16 depends on the eventual use of water in
purification chamber 16. For example, if the water in chamber 16 is
to be used for human consumption the unwanted organisms in the
wastewater need to be killed to render the water suitable for human
consumption. One of the effective ways of killing harmful
organisms, such as bacteria, in wastewater is the use of biocidal
metals that release heavy metals ions and particularly heavy metals
ions such as silver ions. Although silver ions are effective in
killing harmful unwanted organisms the solubility of silver ions in
water is limited and hence the effectiveness in quickly and
effectively killing harmful bacterial is also limited.
[0018] While wastewater treatment involves the removal of
pollutants in the wastewater the type of wastewater treatment
required will depend on the type of wastewater being processed as
well as the final use for the wastewater. For example, if the
wastewater is to be used for human consumption one of the final
processing steps includes the killing of harmful organism in the
wastewater. In the process described herein wastewater is purified
either partly or wholly through the use of a heavy metal ion donor
that releases heavy metal ions such as silver ions. Although silver
ions are effective in killing harmful organisms the low solubility
of the silver ions in water limits the effectiveness of the silver
ions to provide an effective and quick kill of harmful organisms in
the wastewater. In the process described herein the effectiveness
of the metal ions, particularly the silver ions, is enhanced
through increasing the solubility of the silver ions by addition of
a compound containing a hydantoin ring.
[0019] FIG. 5 shows a schematic of the structure of a hydantoin
ring with carbon and nitrogen atoms joined in a five-sided ring. An
oxygen atom is attached to two of the carbons in the hydantoin
ring. The lines extending from the third carbon atom and the
nitrogen atom indicate that other atoms could be attached thereto.
For example, in a compound containing a hydantoin ring, such as DMH
(5,5-dimethylhydantoin), two methyl groups would be attached to the
carbon atom an a hydrogen atom would be attached to each of the two
nitrogen atoms.
[0020] Tests performed by the inventor have demonstrated that two
halogenated hydantoins such as Bromochlorodimethylhydantoin (BCDMH)
and Dibromodimethylhydantoin (DBDMH) when combined with a metal ion
donor may be used in pools and spas to kill microorganisms (U.S.
Pat. No. 7,347,934),
[0021] It has been found that a compound containing a hydantoin
ring such as 5,5-dimethylhydantoin (DMH), which lacks antimicrobial
properties, has the ability to interact with a source of metal ions
to increase the solubility of the silver in wastewater to increase
the effectiveness of the antimicrobial process in the wastewater.
It has also been found that compounds containing a hydantoin ring,
which have antimicrobial properties, such as
Bromochlorodimethylhydantoin (BCDMH) and Dichlorodimethylhydatoin
(DCDMH) Dibromodimethylhydantoin (DBDMH) or silverdimethylhydantoin
(AgDMH) also interact to increase the solubility of silver in the
presence of water. While a number of compounds with a hydantoin
ring may be used as a practical matter one may want to avoid those
compounds where the group or groups on the compound may have an
adverse effect on the sanitized product.
[0022] Examples of other well known compounds wherein the compound
contains a hydantoin ring include 1-hydroxymethyl-5,5-dimethlyl
hydantoin, glycolyurea and Copper hydantoin, Hydantoin-5-acetic
acid, and Imidazolidines including parabanic acid, 2-Thiohydantoin,
hydantoin purum, hydantoin, 1-Aminohydantoin hydrochloride,
2-Imidazolidone, 2-Imidazolidone purum, 2-Imidazolidinethione,
2-hydrazino-2-imidazoline hydrobromide,
2-oxo-1-imidazolidinecarbonyl chloride, 1-methyl hydantoin,
5-methylhydandtoin, 2-imidazolidone-4-carboxylic acid, allantoin,
allantoin purum, creatinine anhydrous, creatinine biochemika,
creatinine hydrochloride, 2-methyl-2-imidazoline,
2-methylithio-2-imdazoline hydrodide,
3-bromo-1-chlor-5-5-dimethlyhydantoin, 1-3-dibromo-5,5-dimethly
hydantoin purium, 1-3-dichlorol-5,5-dimethylhydantoin,
1,3-dichlor-5,5-dimethylhydantoin, hydantoin-5-acetic acid.
2-chlorocarbonyl-1-methanesulfonyl-2imidaz olidinone.
5,5-dimethylhydantoin purum. 5,5-dimethylhydantoin,
2-imino-1-imidaolidineacetic acid, 1,3-dimethyl-2-imidazolidinone
puriss, 1,3-dimethly-2-imidazolidinone purum,
1,3-dimethyl-2-imidazolidinone, 1-(2-hydroxyethyl)-2-imdazolinone,
1,5,5-trimethlylhydantoin, 5-ethyl-5-methylhydantoin,
2-phenyl-2-imidazoline purum,
2-(4,5-dihydro-1h-imidazoyl)-2-phenol,
4-(4,5-dihydro-1H-imidazol-2yl)phenylamine,
5-methyl-5-phentylhydantoin, 2-benzyl imidazoline,
4-(4-methyl-4,5-dihydro-1H-imidazol-2-yl)phenyl, Imidazolidinyl
urea, 4-hydroxymephenyloin,
triethoxy-3-(2-imidazolin-1-yl)propysiliane purum, 1,
(p-tosyl)-3,4,4-trimethylimidazolidine, naphazoline nitrate puriss,
5,5,diphenyl-2-thiohydantoin,
5-(4-hydroxyphenyl)-50phenylhydantion,
5-(p-methylphenyl)-5-phenyhydantoin,
1,3,bisbensyl-2-oxoimidazoline-4,5-dicarboxylic acid. Other
examples of hydantoins are listed in European patent EP0780125
which is hereby incorporated by reference. The above list compounds
with a hydantoin ring is illustrative and no limitation thereto is
intended.
[0023] Tests of a silver ion donor in the presence of DMH in a body
of water reveals that the dissolved silver concentrations are
higher than anticipated when compared to a body of water with the
silver ion donor but without the DMH. The results suggest that DMH
interacts with silver to form a soluble complex even if the
source(s) of silver are from insoluble salts such as silver
bromide, which in some cases may be derived from silver
chloride:
[0024] In order to verify that a compound containing a hydantoin
ring, such as, DMH interacts to increase the solubility of
insoluble silver in a body of water, a test was performed using
either silver chloride or silver bromide as the donor of silver
metal ions. The test demonstrated the enhancement of the silver ion
concentration in a water environment when DMH is used in
combination with the source of silver ions even though the DMH
lacked any independent antimicrobial properties.
EXAMPLE
[0025] Silver bromide was initially prepared from a saturated
sodium bromide solution, combined with silver nitrate in solution.
The yellow precipitate, silver bromide, was than purified by
filtration and washing. Additionally, the solid was allowed to dry
before use.
[0026] A buffer system having a pH of 7.41 was prepared by adding
Fisherbrand.RTM. potassium phosphate monobasic-sodium phosphate
dibasic buffer to 2 Erlenmeyer flasks filled with 1000 mL of
purified water. The first flask was treated with 1.12 grams of
5,5-dimethylhydantoin (DMH) and marked solution "C" (with DMH) and
the second flask was left untreated and marked solution "D"
(without DMH) for control. In regards to the 5,5-dimethylhydantoin
(DMH), the 5,5-dimethylhydantoin (DMH) comprised 97% reagent grade
was obtained from Aldrich.RTM. (CAS No. 77-71-4, Cat. No.
D161403-1KG).
[0027] After the initial set-up, approximately 0.10 grams of dried
silver bromide was introduced into a dialysis tubing
(Fisherbrand.RTM., 45 mm, MWCO 12,000-14,000) along with purified
water. The ends of the dialysis tubing were clamped to contain the
silver bromide and purified water. Next, the outside of the
dialysis tubing was rinsed several times to ensure that silver
bromide residue was not on the outside of the dialysis tubing. A
string was then tied to one clamp, and one tube was introduced into
each flask. A magnetic stir bar was used to mix the solutions.
[0028] During the period of the test, a 100 ml sample were removed
from solution "D" (without DMH) and solution "C" (with DMH) at
weekly intervals and analyzed for their pH using Orin Perphect
Meter 370 and analyzed for their silver ion concentrations using
atomic absorption spectrometry.
[0029] FIG. 2 shows a table containing a list of the dissolved
silver concentration, in parts per billion (ppb) obtained from the
100 ml samples for solution "D" (without DMH) and solution "C"
(with DMH) at each of their respective weekly time intervals. The
average concentration of dissolved silver for solution "C" (with
DMH) was 86 ppb while solution "D" (without DMH) had an average
concentration of dissolved silver of 4.7 ppb.
[0030] A week after the start date, the concentration of dissolved
silver for solution D (without DMH) was at 4.3 ppb, while the
concentration of dissolved silver for solution C (with DMH) was at
2.8 ppb. By the end of the testing, 6 weeks later, the
concentration of dissolved silver for solution C (with DMH) had
increase to 220 ppb, while the concentration of dissolved silver
for solution D (without DMH) was 7.1 ppb. That is, by the end of
the 6 weeks test, the concentration of dissolved silver was at
least 30-fold greater in solution C (with DMH) then for solution D,
(without DMH).
[0031] In summary, the results of the above testing confirmed that
in a solution containing silver bromide, the presence of compound
containing a hydantoin ring, such as DMH, leads to a higher
dissolved silver concentrations than compared to a control solution
containing silver bromide without the presence of the DMH. These
results suggest that compounds containing a hydantoin ring, which
may not have any antimicrobial properties, can interact with silver
to form a soluble complex even if the source of silver comprises an
extremely insoluble silver salt such as silver bromide.
[0032] In regards to generating a level of silver ions in a body of
water, the King Technology, Inc. Frog.RTM. Mineral Cartridge is
known to provide silver ions in the form of solid silver chloride
(AgCl) distributed over a porous matrix. Water flowing through the
matrix comes into contact with the AgCl resulting in the release of
soluble silver ions to water. DMH was also released into the water
resulting in the formation of ionic-hydantoin structures. It would
be anticipated that soluble silver ions would be depleted from
water through the formation of silver bromide, an insoluble salt.
However, as shown in FIG. 2 after the DMH was added to the water,
the actual silver concentrations were higher than the calculated
theoretical silver concentration.
[0033] Referring to FIGS. 3 and 4, FIG. 3 shows a dispenser 20
having a housing 21 containing a compartment 22 therein for the
compound containing the hydantoin ring and a source of biocidal
metal ions such as silver ions. Located in compartment 22 is a
compound 23 containing a hydantoin ring such as DMH and a biocidal
component such a biocidal metal for generating biocidal metal ions
into a body of wastewater. Although various types of biocidal metal
such as zinc or copper may be use, the preferred biocidal metals
comprise silver, silver alloy or some combination thereof, because
of the recognized bactericidal, viricidal, and algaecidal
properties of silver. The biocidal metals can be introduced as
metallic, zero valence material, or as metal ions that can be
introduced into the water by dissolution of soluble metal salts, or
by the dissolution of the metal itself. For example, silver ion can
be introduced into the water through the dissolution of silver
nitrate, or through the dissolution of metallic silver as the
result of conversion to silver oxide and subsequent conversion of
the oxide to more soluble silver species. Mixtures of different
salts, or of salts with metallic material, may be combined together
to provide the necessary concentration of metal ions in the water.
In the embodiment of FIG. 3, the biocidal metal is in a dry or
inactive state and comprises either metallic silver or a source of
silver ions, such as silver chloride 24. Similarly, the compound
containing the hydantoin ring is also in a dry or inactive state,
with both compound containing the hydantoin ring and the silver
chloride entering into an active state in the presence of
wastewater. A set of openings 25 allows water access to compartment
22 and to the source of the compound containing a hydantoin ring 23
and the source of silver ions 24.
[0034] It is noted that various insoluble or slightly soluble
transition metal salts may also be used in the present invention as
a source of silver ions. Examples of insoluble or slightly soluble
transition metal salts suitable for use in the present invention
include, but are not limited to, AgCl, AgBr, AgI, Ag.sub.2S,
Ag.sub.3PO.sub.4, NaAg.sub.2PO.sub.4, CuS, and NaCuPO.sub.4. Other
examples of silver compounds include, but are not limited to,
AgNO.sub.3, Ag.sub.2CO.sub.3, AgOAc, Ag.sub.2SO.sub.4, Ag.sub.2O,
[Ag(NH.sub.3).sub.2]Cl, [Ag(NH.sub.3).sub.2]Br,
[Ag(NH.sub.3).sub.2]I, [Ag(NH.sub.3).sub.2]NO.sub.3,
[Ag(NH.sub.3).sub.2].sub.2SO.sub.4, silver acetoacetate a silver
benzoate, a silver carboxylate, silver amine complexes such as
[Ag(NR.sub.3).sub.2]X, where R is an alkyl or aryl group or
substituted alkyl or aryl group and X is an anion such as, but not
limited to, Cl.sup.-, Br.sup.-, I.sup.-, OAc.sup.-, NO.sub.3.sup.-
and SO.sub.4.sup.2-.
[0035] FIG. 4 shows a further example of wasterwater treating
system including a dispenser 26 having a first housing 27
containing a compartment 28 and a second housing 29 with a
compartment 30 therein. Located in compartment 28 is a silver ion
donor such as metallic silver 31 and located in compartment 30 is a
source of compound 32 containing a hydantoin ring such as DMH. A
set of openings 33 allows water access to compartment 28 and to the
metallic silver 31. Similarly, a set of openings 34 allows water
access to compartment 30 and the source of DMH.
[0036] Although the use of the silver ion donor such as silver,
silver oxide, silver salt, or a combination thereof have been
disclosed in the present invention, various types of silver alloys
may also be used. The silver may be used standing along in its
pure/elemental or alloyed form or coated or impregnated to a
substrate and placed in compartment 28. In addition, other types of
silver ion donors, other types of transition metal, a transition
metal oxide, or a combination thereof, and other alternative
bactericides whose solubility can be changed in the presence of DMH
can also be used in the present invention.
[0037] In regards to the source of DMH 23, 32 of FIGS. 3 and 4,
note that FIG. 3 shows source of compound containing a hydantoin
ring 22 in particle form with the aforementioned particles having
an initial size that is larger than the size of opening 23 to
prevent the particles from escaping through opening 23. FIG. 3
shows source of compound containing a hydantoin ring 23 in tablet
form. In regards to the tablets, it is noted that various types of
material, including but not limited to microcrystalline cellulose
(MCC), may be used as a binder in the formation of the santizing
tablets which are tabletized with a metal ion donor so that both
the compound containing a hydantoin ring and the metal ion donor
can be placed in the body of fluid to be treated.
[0038] It is also noted that the preferred level of the compound
containing a hydantoin ring in his case which is DMH is present in
the body of wastewater is between 5 and 25 ppm with the DMH and the
source of silver cooperating to maintain a level of silver ions
present in the amount of 1 to 3 ppb and/or alternatively
cooperating to maintain a level of silver ions present to sustain a
standard plate count at 35 degrees F. of less than 200 colonies per
milliliter.
[0039] Thus the invention includes an antimicrobial agent for
killing microorganisms in a body of wastewater wherein the
antimicrobial agent includes a source of biocidal metal ions
releasable into the body of wastewater to generate an antimicrobial
level of biocidal metals that may be insufficient to kill the
microorganisms in the body of wastewater and a compound containing
a hydantoin ring releasable into the body of wastewater wherein the
compound containing the hydantoin ring increases the antimicrobial
level of biocidal metal ions in the body of wastewater to a
biocidal level sufficient to kill microorganism in the
wastewater.
[0040] The invention also includes the step of placing the
dispenser 20, 26 containing both the source of compound 23
containing a hydantoin ring, and the source of silver ions 24, 31
in the body of wastewater and allowing water to come into contact
with the DMH 33, 32 and the source of silver ion 24, 31 to
periodically release DMH and silver ions into the body of
wastewater. As the DMH is released into the body of wastewater, the
DMH is carried to the source of silver ions 24, 31 and interacts
with the source of silver 24, 31 to increase the solubility of the
silver ions to allow for the release of more silver ions into the
body of wastewater than if the source of silver ions 24, 31 alone
thereby increasing the level of silver ions to a level sufficient
to kill the microorganisms in the wasterwater.
[0041] The invention also include a method of treating a body of
wastewater to kill microorganisms by enhancing the microbial agents
comprising the steps of (1) adding a biocidal component 14, 21 to
the body of wastewater; and (2) adding a concentration of compound
containing a hydantoin ring such as 5,5-dimethylhydantoin 13, 22 to
the body of wastewater to enhance the effectiveness of the biocidal
component 14, 21 in the body of wastewater to thereby lessen the
need for a supplemental biocide. The aforementioned method can also
include the steps of (3) adding a transition metal, a transition
metal oxide, a transition metal salt, or a combination thereof to
the body of wastewater; (4) adding silver, silver oxide, silver
salt, or a combination thereof to the body of wastewater; (5)
adding a substrate that has been coated or impregnated with
metallic silver, silver salt, or a combination thereof to the body
of wastewater; (6) a silver alloy to the body of wastewater; (7)
adding silver nitrate to the body of wastewater; (8) adding a
carrier containing a silver deposit to the body of wastewater; (9)
adding a silver-containing material to the body of wastewater; (10)
placing a dispenser 10, 16 containing both the biocidal component
14, 21 and the 5,5-dimethylhydantoin 13, 22 in the body of
wastewater and allowing water to come into contact with both the
biocidal component 14, 21 and the 5,5-dimethylhydantoin 13, 22;
(11) adding an amount of 5,5-dimethylhydantoin 13, 22 in the body
of wastewater to obtain a final concentration of at least 5 ppm
5,5-dimethylhydantoin; and adding a supplemental water disinfection
system comprising sodium bromide.
[0042] The invention further includes a method of treating a body
of wastewater to kill microorganisms by increasing the
effectiveness of an antimicrobial agents comprising the steps of:
(1) adding a source of biocidal metal 14, 21 to the body of
wastewater to generate biocidal metal ions in the body of
wastewater; and (2) adding compound containing a hydantoin ring
such as 5,5-dimethylhydantoin 13, 22 to the body of wastewater to
interact with the biocidal metal 14, 21 to enhance the biocidal
metal ion concentration in the body of wastewater. The
aforementioned method can also include the steps of (3) adding a
source of metallic silver to the body of wastewater; (4) adding
metallic silver alloy 14, 21 to the body of wastewater; (5) placing
a dispenser 10, 16 containing both the source of biocidal metal 14,
21 and the compound containing a hydantoin ring such as
5,5-dimethylhydantoin 13, 22 in the body of wastewater and allowing
water to come into contact with both the source of biocidal metal
14, 21 and the 5,5-dimethylhydantoin 13, 22; (6) adding a metallic
silver coated or impregnated substrate 14, 21 to the body of
wastewater; and adding a source of pure silver 14, 21 to the body
of wastewater.
[0043] Thus, as described herein one example a wastewater
antimicrobial agent may include a biocidal metal selected from the
group consisting of silver chloride, a metallic silver alloy, pure
silver or a substrate impregnated with metallic silver and the
compound containing the hydantoin ring where the compound
containing the hydantoin ring may be either a non-halogenated
hydantoin such as 5,5-dimethylhydantoin (DMH) or a halogenated
hydantoin including Bromochlorodimethylhydantoin (BCDMH) or
Dichlorodimethylhydatoin (DCDMH) or combinations thereof and the
compound containing the hydantoin ring is in either a liquid state
or a dry state including, powder, solid, granules, pellets or
combinations thereof.
* * * * *