| United States Patent Application |
20040129644
|
| Kind Code
|
A1
|
|
Unhoch, Michael J.
|
July 8, 2004
|
Method of water treatment
Abstract
The invention relates to a method of treatment of bodies of water such as
recreational pools, spas and hot tubs with maintenance doses of water
treatment chemicals to achieve consistent sanitization and aesthetically
pleasing levels of properties such as turbidity. The amount of the
maintenance doses is based on the volume of water to be treated in order
to achieve hygienic and clear water.
The method can be automated for accurate, consistent and safe treatment of
water such as found in swimming pools, spas or hot tubs.
| Inventors: |
Unhoch, Michael J.; (Willmington, DE)
|
| Correspondence Name and Address:
|
John A. Parrish
Law Offices Of John A. Parrish
Suite 300
Two Bala Plaza
Bala Cynwyd
PA
19004
US
|
| Serial No.:
|
691479 |
| Series Code:
|
10
|
| Filed:
|
October 22, 2003 |
| U.S. Current Class: |
210/749 |
| U.S. Class at Publication: |
210/749 |
| Intern'l Class: |
C02F 001/68; C02F 001/50; C02F 001/72 |
Claims
1. A method of treating a volume of water to maintain a predetermined
amount of a water treatment chemical in the volume of water over a time
period comprising, determining an amount of a water treatment chemical to
be preserved in a volume of water to be treated, calculating a
maintenance dose of the chemical to be added to the volume of water to
maintain about the amount of the chemical in the water over the time
period, providing a source of the chemical, and supplying the maintenance
dose of the water treatment chemical to the volume of water, wherein the
maintenance dose is calculated according to equation (1): MD=(PV)(DC)
(1) where MD=Maintenance dose of water treatment chemical PV=Volume of
water to be treated DC=Consumption of water treatment chemical over the
time period and wherein the supplying of the maintenance dose is
performed by a pump having a pump tube displacement and which is caused
to operate for a run time determined according to equation (2)
RT=((K)(MD)/(PRM.times.PTD)) (2) where: RT=Run time of pump (sec)
PRPM=Pump speed (RPM) PTD=Pump tube displacement (ml)/pump revolution
K=1776 ((sec-ml)/(min-oz)), and MD is defined as in equation (1).
2. The method of claim 1 wherein the source of the chemical is an aqueous
solution of the chemical.
3. The method of claim 2 wherein the solution has about 0.5 wt. % (active)
to about 80 wt. % (active) water treatment chemical.
4. The method of claim 1 wherein the pump is caused to operate by a
computer programmed according to equation (2).
5. The method of claim 1 wherein the chemical is selected from the group
consisting of algicides, sanitizers, oxidizers, chelating agents, pH
control agents, corrosion inhibitors and stabilizers.
6. The method of claim 1 wherein the chemical is selected from the group
consisting of chlorine dioxide, lithium hypochlorite, sodium
hypochlorite, (poly(hexamethylene biguanide) hydrochloride),
1,3-bromo-chloro-dimethylhydantoin, and 1,3-dibromodimethylhydantoin,
hydrogen peroxide, potassium monopersulfate, sodium perborate, sodium
percarbonate, copper sulphate, copper citrate, copper EDTA (ethylene
diaminetetraacetic acid), copper gluconate,
colloidal silver, silver
nitrate, poly(oxyethylene (dimethylimino) ethylene (dimethylimino)
ethylene dichloride), sodium dimethyldithiocarbamate,
2-chloro-4,6-bis(ethylamino)-5-triazine, zinc chloride, zinc oxide, and
benzyl alkonium chloride.
7. The method of claim 1 wherein the chemical is selected from the group
consisting of alkali metal hypochlorite, alkaline earth metal
hypochlorite, chlorinated isocyanurates, halogenated hydantoins, alkali
metal perborates, alkali metal percarbonates, copper salts, silver salts,
quaternary ammonium compounds, polyquaternary ammonium compounds, zinc
salts, chelating agents, fungicides, pH control agents, corrosion
inhibitors, and stabilizers.
8. The method of claim 1 wherein the water treatment chemical is hydrogen
peroxide.
9. The method of claim 3 wherein the water treatment chemical is sanitizer
added in a maintenance dose of about 0.1 ppm/day to about 6 ppm/day.
10. The method of claim 3 wherein the water treatment chemical is
sanitizer added in a maintenance dose of about 1 ppm/day to about 3
ppm/day.
11. A system for treating a volume of water to maintain a predetermined
amount of a water treatment chemical in the volume of water over a time
period comprising, a pump having a pump tube displacement cooperatively
connected to a computer for control of the pump, a source of chemical for
supply to the pump for delivery by the pump to a volume of water, causing
the pump to operate for a time sufficient to supply an amount of water
treatment chemical to the volume of water sufficient to maintain about
the predetermined amount of water treatment chemical in the volume of
water over the time period, wherein the pump is caused to operate for a
run time (RT) calculated as the quotient of ((K)(MD)/(PRM.times.PTD))
where: RT=Run time of pump (sec) PRPM=Pump speed (RPM) PTD=Pump tube
displacement (ml)/pump revolution K=1776 ((sec-ml)/(min-oz)), and
MD=(PV)(DC) where MD=Maintenance dose of water treatment chemical
PV=Volume of water to be treated DC=Consumption amount of water treatment
chemical over the time period
12. The method of claim 11 wherein the source of the chemical is an
aqueous solution of the chemical.
13. The method of claim 12 wherein the solution has about 1 wt. % (active)
to about 80 wt. % (active) water treatment chemical.
14. The method of claim 11 wherein the pump is caused to operate by a
computer programmed according to equation (2).
15. The method of claim 11 wherein the chemical is selected from the group
consisting of algicides, sanitizers, oxidizers, chelating agents, pH
control agents, corrosion inhibitors and stabilizers.
15. The method of claim 9 wherein the chemical is selected from the group
consisting of chlorine dioxide, alkali metal hypochlorite, alkaline earth
metal hypochlorite, chlorinated isocyanurates, (poly(hexamethylene
biguanide) hydrochloride)halogenated hydantoins, hydrogen peroxide,
potassium monopersulfate, chlorine dioxide, alkali metal perborates,
alkali metal percarbonates, copper salts, copper sulphate, copper
citrate, copper EDTA (ethylene diaminetetraacetic acid), copper
gluconate,
colloidal silver, silver salts, silver nitrate, quaternary
ammonium compounds, polyquaternary ammonium compounds, poly(oxyethylene
(dimethylimino) ethylene (dimethylimino) ethylene dichloride), sodium
dimethyldithiocarbamate, 2-chloro-4,6-bis(ethylamino)-5-triazine, zinc
salts, zinc chloride, zinc oxide, benzyl alkonium chloride, chelating
agents, fungicides, pH control agents, corrosion inhibitors, and
stabilizers.
16. The method of claim 11 wherein the chemical is selected from the group
consisting of chlorine dioxide, lithium hypochlorite, sodium
hypochlorite, (poly(hexamethylene biguanide) hydrochloride),
1,3-bromo-chloro-dimethylhydantoin, and 1,3-dibromodimethylhydantoin,
hydrogen peroxide, potassium monopersulfate, sodium perborate, sodium
percarbonate, copper sulphate, copper citrate, copper EDTA (ethylene
diaminetetraacetic acid), copper gluconate,
colloidal silver, silver
nitrate, poly(oxyethylene (dimethylimino) ethylene (dimethylimino)
ethylene dichloride), sodium dimethyldithiocarbamate,
2-chloro-4,6-bis(ethylamino)-5-triazine, zinc chloride, zinc oxide, and
benzyl alkonium chloride.
17. The method of claim 11 of alkali metal hypochlorite, alkaline earth
metal hypochlorite, chlorinated isocyanurates, halogenated hydantoins,
alkali metal perborates, alkali metal percarbonates, copper salts, silver
salts, quaternary ammonium compounds, polyquaternary ammonium compounds,
zinc salts, chelating agents, fungicides, pH control agents, corrosion
inhibitors, and stabilizers.
18. The method of claim 11 wherein the water treatment chemical is
hydrogen peroxide.
19. The method of claim 13 wherein the water treatment chemical is
sanitizer added in a maintenance dose of about 0.1 ppm/day to about 6
ppm/day.
20. The method of claim 13 wherein the water treatment chemical is
sanitizer added in a maintenance dose of about 1 ppm/day to about 3
ppm/day.
21. A system for treating a volume of water to maintain a predetermined
amount of a water treatment chemical in the volume of water over a time
period comprising, a device for delivering a water treatment chemical to
a volume of water, causing the device to operate for a time sufficient to
deliver a maintenance dose of water treatment chemical sufficient to
maintain about the predetermined amount of water treatment chemical in
the volume of water over the time period, wherein the maintenance dose
(MD)=(PV)(DC) where MD=maintenance dose of water treatment chemical
PV=Volume of water to be treated DC=Consumption amount of water treatment
chemical over the time period.
22. A method for treating a volume of water to maintain a predetermined
amount of a water treatment chemical in the volume of water over a time
period comprising, delivering a water treatment chemical to a volume of
water by a device controlled by a computer, operating the device for a
time sufficient to deliver a maintenance dose of water treatment chemical
sufficient to maintain about the predetermined amount of water treatment
chemical in the volume of water over the time period, wherein the
maintenance dose (MD)=(PV)(DC) where MD=maintenance dose of water
treatment chemical PV=Volume of water to be treated DC=Consumption amount
of water treatment chemical over the time period.
Description
[0001] This application claims priority to U.S. provisional application
60/423,790, filed Nov. 4, 2002.
FIELD OF THE INVENTION
[0002] The invention relates to methods for sanitation and clarification
of water
BACKGROUND OF THE INVENTION
[0003] Recreational pools such as swimming pools, spas and hot tubs
provide a great deal of pleasure and comfort. The extent of comfort
depends on the quality of the water. In order to assure comfort and
safety to users of these pools, it is important that the water be treated
properly so that it is aesthetically pleasing in terms of taste, color,
turbidity and odor. Proper treatment also is important so that the water
has proper pH, and is environmentally safe as well as effectively free of
pathogens and chemicals which may cause illness.
[0004] Conventional methods of treatment of water in recreational pools
utilize water treatment chemicals such as oxidizers, sanitizers,
algicides and pH buffers. Typically, the chemicals are measured and
manually added to the water as part of an overall water maintenance
program. In such a program, various water quality parameters are measured
at regular intervals. When a parameter is not acceptable, an appropriate
amount of water treatment chemical is measured and manually added to the
water. In so doing, the user is undesirably exposed to the concentrated
chemical.
[0005] Mixtures of chemicals also have been added to recreational pool
water. Addition of mixtures of chemicals to promote water clarity is
shown in U.S. Pat. No. 5,501,802. This patent discloses a mixture that
includes polyhexamethylene biguanide sanitizer, persulfate salt oxidizers
and chelating agents. U.S. Pat. Nos. 5,514,287 and 5,478,482 disclose a
composition and a method for controlling microbial growth in
recirculating water systems. The composition includes a soluble boron
contributor, a halogen/boron sanitizer/algicide, and an oxidizing
clarifier which includes a chlorine compound, a non-halogen oxidizer, and
a boron source.
[0006] U.S. Pat. No. 4,846,979 discloses an algicide composition for
treating swimming pools and spas. The algicide composition includes an
alkali metal, alkaline earth metal or ammonium bromide and an oxidizer.
[0007] A popular sanitizer for water treatment is based on the polymeric
biguanide described in U.S. Pat. No. 4,014,676. Use of polymeric guanides
such as BAQUACIL.RTM. Sanitizer and Algistat sold by Avecia Inc. is
popular because they do not cause eye irritation that is common with use
of chlorine.
[0008] Water treated with BAQUACIL.RTM. Sanitizer and Algistat also can be
treated with a separate algicide to combat algae. Oxidizers such as those
which include hydrogen peroxide as the active component also may be added
to the treated water to oxidize organic compounds in the water to promote
clarity. An example of such an oxidizer is BAQUACIL.RTM. Shock and
Oxidizer (from Avecia Inc.). BAQUACIL.RTM. Shock and Oxidizer is an
aqueous solution that includes 27.5% hydrogen peroxide.
[0009] Consumers typically treat water found in pools, spas and hot tubs
with chemicals such as sanitizers, oxidizers and algicides. Due to
complexities such as the differing times specified for dosing various
water treatment chemicals, difficulties in accurately measuring dosages,
exposure to chemicals as well as cost of chemicals, consumers tend to
avoid treating the water until problems such as haze and algae build-up
occur.
[0010] A need therefore exists for a method that avoids these complexities
and enables ready treatment of water such as that found in recreational
pools.
SUMMARY OF THE INVENTION
[0011] The invention achieves controlled, continuous introduction of
sanitizing and clarifying chemicals into water to maintain a desired
residual level of those chemicals. The method may be employed in an
automated dosing system.
[0012] In a first aspect, the invention relates to a method of treatment
of bodies of water such as recreational pools, spas and hot tubs with
maintenance doses of water treatment chemicals to achieve consistent
sanitization and aesthetically pleasing levels of properties such as
turbidity. The amount of the maintenance dose is based on the volume of
water to be treated in order to achieve hygienic and clear water. More
particularly, in this aspect a volume of water is treated to maintain a
predetermined amount of a water treatment chemical. The method entails
determining an amount of a water treatment chemical to be preserved in a
volume of water to be treated. A maintenance dose of the chemical is
added to the volume of water to maintain about the amount of the chemical
in the water over a desired time period. The maintenance dose is
determined from MD=(PV)(DC) where MD=Maintenance dose of water treatment
chemical, PV=Volume of water to be treated, and DC=Consumption amount of
water treatment chemical over that desired time period. The maintenance
dose may be supplied by a pump that has a pump tube displacement and
which operates for a run time RT as determined by RT=((K)(MD)/(PRPM.times-
.PTD)) where:
[0013] RT=Run time of pump (sec)
[0014] PRPM=Pump speed (RPM)
[0015] PTD=Pump tube displacement (ml)/pump revolution
[0016] K=1776 ((sec-ml)/(min-oz)), and
[0017] MD is defined as above.
[0018] In another aspect, the invention relates to a system for treating a
volume of water to maintain a predetermined amount of a water treatment
chemical in the volume of water. The system includes a device for
delivering a water treatment chemical to a volume of water where the
device preferably is controlled by a computer. The device is caused to
operate for a time sufficient to deliver a maintenance dose of water
treatment chemical sufficient to maintain the predetermined amount of
water treatment chemical in the volume of water over a desired time
period. The maintenance dose (MD)=(PV)(DC) where MD=maintenance dose of
water treatment chemical, PV=Volume of water to be treated, and
DC=Consumption amount of water treatment chemical over that desired time
period.
[0019] The method of the invention achieves significant advantages. The
method enables maintenance of a desired residual amount of a water
treatment chemical such as a sanitizer, oxidizer or algicide in the water
to control bacteria and nuisance algae and to achieve consistently low
levels of turbidity. The maintenance dose may be added without the need
for first measuring the amount of a water treatment chemical in the water
prior to adding the maintenance dose of water treatment chemical as with
manual additions of the chemical.
[0020] The method achieves water clarification in conjunction with an
existing overall water maintenance program without adversely affecting
other water quality parameters. The invention advantageously achieves
improved water clarity and reduced amounts of algae on a consistent
basis.
[0021] The method may be automated to minimize consumer exposure to
chemicals, and to avoid errors of measurement that produce incorrect
dosing of chemicals. Existing technology such as existing automatic
dosing technology requires the customer to first calculate the dose of
chemicals appropriate for effective treatment of their pool, spas and the
like. Maintenance dosing as in the invention avoids the inaccuracies of
under/overdosing associated with manual additions of water treatment
chemicals. Automated maintenance dosing by a device such as a
programmable pump, as in, for example, the BAQUACIL AD.TM. Automated
Dosing System from Avecia, Inc., provides an accurate, consistent and
safe method of dosing water treatment chemicals.
[0022] Although the method may be used to treat pools, spas, hot tubs and
the like, it is particularly suitable for treating recreational pools.
The invention, in addition to treatment of recreational water such as
swimming pools and hot tubs, may be used in a variety of other water
treatment applications. Examples of these applications include home water
treatment, community water treatment, industrial water treatment,
agriculture, water reuse and groundwater injection.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Water treatment chemicals which may be used in the method include
but are not limited to sanitizers, oxidizers and algicides. Sanitizers
which may be employed include but are not limited to oxidizing biocides
and non-oxidizing biocides.
[0024] Oxidizing biocides which may be used include but are not limited to
chlorine dioxide, alkali metal hypochlorite such as lithium hypochlorite
and sodium hypochlorite, alkaline earth metal hypochlorites such as
calcium hypochlorite, chlorinated isocyanurates, sodium
dichloro-s-triazinetrione, trichloro-s-triazinetrione and potassium
dichloro-s-triazine trione, and halogenated hydantoins such as
1,3-bromo-chloro-dimethylhydantoin, and 1,3-dibromodimethylhydantoin.
[0025] Non-oxidizing biocides which may be used include but are not
limited to (poly(hexamethylene biguanide) hydrochloride) such as
BAQUACIL.RTM. from Avecia, preferably (poly(hexamethylene biguanide)
hydrochloride.
[0026] Oxidizers which may be employed include but are not limited to
peroxides such as hydrogen peroxide, potassium monopersulfate, chlorine
dioxide, alkali metal perborates such as peroxide release agents as
illustrated by sodium perborate, sodium persulfate, potassium
monopersulfate and sodium percarbonates. Preferably, the oxidizer is
hydrogen peroxide.
[0027] Algicides which may be employed include but are not limited to
copper salts such as copper sulphate, copper citrate, copper EDTA
(ethylene diaminetetraacetic acid), and copper gluconate, copper TEA
(triethanolamine),
colloidal silver, silver salts such as silver nitrate,
quaternary or polyquaternary ammonium compounds such as poly(oxyethylene
(dimethylimino) ethylene (dimethylimino) ethylene dichloride) available
from Buckman Corp. under the trademame WSP, sodium
dimethyldithiocarbamate, 2-chloro-4,6-bis(ethylamino)-5-triazine, zinc
salts such as zinc chloride and zinc oxide, benzyl alkonium chloride
available from Lonza Corp. Preferably, the algicide is benzyl alkonium
chloride.
[0028] Other chemicals which may be employed in the method include, for
example, chelating agents such as ethylene diaminetetra acetic acid and
triethanolamine, fungicides, pH control agents (acids and bases),
corrosion inhibitors, and stabilizers.
[0029] An initial, predetermined amount of a water treatment chemical such
as sanitizer, oxidizer, and algicide is added to the water. This initial
amount typically is sufficient to inactivate biological contaminants in
the volume of water undergoing treatment. Each of the sanitizer, oxidizer
and algicide may be provided in the form of liquid, powder or gas. Where
an aqueous solution of the water treatment chemical is employed, the
aqueous solution has about 1% to about 80% (active) water treatment
chemical. Accordingly, where a sanitizer is employed, the aqueous
solution has about 1 wt. % to about 80 wt. % (active) sanitizer.
Similarly, where an oxidizer is employed, the aqueous solution has about
0.5 wt. % to about 80 wt. % (active) oxidizer. Mixtures of water
treatment chemical also may be employed.
[0030] The initial, predetermined amount of water treatment chemical is
followed by one or more maintenance doses of the water treatment
chemical. The maintenance doses are added in amounts sufficient to
maintain a desired amount of the water treatment chemical in the water
over a desired time period such as 24 hours. The maintenance dose may be
the same or different from the initial amount of water treatment chemical
added to the water. Preferably, maintenance doses of individual water
treatment chemical are added to the volume of water. Mixtures of water
treatment chemicals also may be added as a maintenance dose.
[0031] The maintenance dose of water treatment chemical added to the
volume of water undergoing treatment is calculated according to equation
(1):
MD=(PV)(DC) (1)
[0032] where
[0033] MD=maintenance dose of water treatment chemical (oz.) added to
compensate for loss of water treatment chemical over a given time period
[0034] PV=Volume of water to treated (gallons)
[0035] DC=Consumption amount of water treatment chemical in the volume of
water (oz. water treatment chemical/1000 gallons water) over the given
time period.
[0036] DC is determined by measuring the consumption of a particular water
treatment chemical in the type of water system being treated over a given
time period. The consumption of the water treatment chemical can be
determined by using known analytical techniques.
[0037] Maintenance doses of water treatment chemicals are added at
selected time intervals, such as every 24 hours, to maintain a desired
amount of water treatment chemical in the water. Maintenance doses of
sanitizer such as BAQUACIL.RTM. Sanitizer and Algistat typically range
from about 0.1 ppm/day to about 6.0 ppm/day, preferably about 1.0 ppm/day
to about 3.0 ppm/day. The maintenance doses may be added based on a
single determination of DC and while avoiding the need to re-measure the
amount of water treatment chemical in the water.
[0038] The initial dose of oxidizer is added to the volume of water in an
amount sufficient to oxidize organic material initially present in the
volume of water. Maintenance doses of oxidizer then are added to maintain
that amount of oxidizer. Maintenance doses of oxidizers such as
BAQUACIL.RTM. Shock and Oxidizer from Avecia typically range from about
0.5 ppm/day to about 10.0 ppm/day.
[0039] The initial dose of algicide is added to the volume of water in an
amount sufficient to prevent algal growth or bloom as determined
visually. Maintenance doses of algicide are added in amounts sufficient
to prevent algal growth or bloom over a period of 24 hours as determined
visually.
[0040] The method of water treatment may be performed manually, and also
may be automated. The method can be programmed into a device such as a
pump to deliver a maintenance dose. The method may be automated by use of
a supply device such as a tablet dispenser, powder dispenser, erosion
feeder, venturi feeder, gas feeder, and pumps, preferably, a programmable
pump. The device such as a pump can be programmed to operate at specific
times for specific run time intervals to add maintenance doses of water
treatment chemicals to the volume of water undergoing treatment.
[0041] The run-time during which the pump is operated to deliver a
maintenance dose is calculated according to equation (2):
RT=((K)(MD)/(PRPM.times.PTD)) (2)
[0042] where:
[0043] RT=run time of pump (sec) to deliver MD
[0044] PRPM=Pump speed (RPM)
[0045] PTD=pump tube displacement (ml)/pump revolution
[0046] K=conversion constant (1776 ((sec-ml)/(min-oz)).
[0047] MD is defined as in equation (1)
[0048] To illustrate, assume a pool volume (PV) of 10,000 gal, and that
(DC) of the water treatment chemical in the pool is 0.125 oz/1000gal/day.
Substituting into Eq. (1), MD is calculated as 1.25 oz. Substituting into
Eq. (2), where PRPM=20 and PTD=2, the RT of the pump is calculated as
55.5 sec.
[0049] A programmable pump useful in the water treatment method is the
BAQUACIL AD.TM. Automated Dosing System from Avecia Inc. The BAQUACIL
AD.TM. Automated Dosing System includes a dispensing unit that employs
two pumps. The pumps are controlled by computer chip programmed according
Equations (1) and (2).
[0050] A programable pump also may be used to add an initial dose of a
water treatment chemical such sanitizer, oxidizer and algicide to
freshly-filled (or newly converted) water systems, as well as to
administer top-up doses of sanitizer, algicide and oxidizer to
established volumes of water to achieve a desired chemistry.
[0051] To illustrate the benefits of the invention, a set of 16
recreational test pools and a set of four recreational control pools are
treated to compare the effect of maintenance doses of water treatment
chemicals on control of water clarity and algae versus conventional
weekly--monthly manual dosing of the same chemicals. The treatments also
are done to evaluate automated additions of maintenance doses to confirm
that the residual amount of water treatment chemical such as sanitizer
can be maintained above 30 ppm.
[0052] Automated additions of maintenance doses to the 16 test pools are
made by using a programmable pump such as that in the BAQUACIL AD.TM.
Automated Dosing System from Avecia. The four control pools are manually
treated with maintenance doses. Each test pool is treated with a
predetermined, initial dose of sanitizer, oxidizer and algicide by using
the BAQUACIL AD.TM. Automated Dosing System.
[0053] An initial dose of the sanitizer BAQUACIL AD.TM. Sanitizer and
Algistat (20% PHMB, polyiminoimidocarbonyliminoimidocarbonyl
hexamethylene hydrochloride, US EPA Reg. No. 72674-19) from Avecia Inc.
is added as above in the amount of 64 oz/10,000 gallons to achieve 50 ppm
of the sanitizer in each test pool. Similarly, an initial dose of the
oxidizer BAQUACIL AD.TM. Shock and Oxidizer (27.5% hydrogen peroxide)
from Avecia Inc., is added as above in the amount of at 128 oz/10,000
gallons to achieve 100 ppm of the oxidizer in each test pool. An initial
dose of the algicide BAQUACIL AD.TM. Algicide 10 (9.96% n-alkyl
(C.sub.14, 60%; C.sub.16, 30%; C.sub.12, 5%; C.sub.18, 5%) dimethyl
benzyl ammonium chloride, dialkyl (C.sub.14, 60%; C.sub.16, 30%;
C.sub.12, 5%; C.sub.18, 5%) methyl benzyl ammonium chloride in water, US
EPA Reg. No. 6836-247-72674) from Avecia Inc. is added as above in the
amount of 32 oz (10% active)/10,000 gallons to achieve 2.4 ppm of the
algicide in each test pool.
[0054] After having added the initial doses, each of the test pools is
treated at 24-hour intervals with maintenance doses of the sanitizer,
oxidizer, and algicide by using a programmable pump according to equation
(2). A programmable pump is included in the BAQUACIL AD.TM. Automated
System. Each test pool receives a maintenance dose of 1.25 oz of BAQUACIL
AD.TM. Sanitizer and Algistat oxidizer per 10,000 gallons pool water, 4.6
oz of BAQUACIL AD.TM. Shock and Oxidizer per 10,000 gallons pool water,
and 1.14 oz of algicide BAQUACIL AD.TM. Algicide 10 per 10,000 gallons
pool water. The maintenance dose of sanitizer is in the form of a 20 wt.
% aqueous solution, the maintenance dose of oxidizer is in the form of a
27.5 wt. % aqueous solution, and the maintenance dose of algicide is in
the form of a 10 wt. % aqueous solution.
[0055] Each control pool is treated with an initial, predetermined dose of
sanitizer, oxidizer and algicide water treatment chemicals. These initial
doses are measured and manually added by pouring the chemicals around the
perimeter of the pool. The initial dose of the sanitizer BAQUACIL.RTM.
Sanitizer and Algistat (20% PHMB, polyiminoimidocarbonyliminoimidocarbony-
l hexamethylene hydrochloride, EPA Reg. No. 72674-19) from Avecia Inc. is
added manually to each of the control pools to achieve 50 ppm of
sanitizer in each pool. Similarly the initial dose of the oxidizer
BAQUACIL.RTM. Shock and Oxidizer (27.5% hydrogen peroxide) from Avecia
Inc. is added to achieve 100 ppm of oxidizer in each control pool. The
initial dose of the algicide BAQUACIL.RTM. Algicide (49.8% n-alkyl
(C.sub.14, 60%; C.sub.16, 30%; C.sub.12, 5%; C.sub.18, 5%) dimethyl
benzyl ammonium chloride, 0.2% dialkyl (C.sub.14, 60%; C.sub.16, 30%;
C.sub.12, 5%; C.sub.18, 5%) methyl benzyl ammonium chloride in water EPA
Reg. No. 72674-20) from Avecia Inc. is added to achieve 2.0 ppm of
algicide in each control pool.
[0056] Maintenance doses of BAQUACIL.RTM. sanitizer are added manually
every 10-14 days to the control pools. Maintenance doses of BAQUACIL.RTM.
sanitizer are added when the measured BAQUACIL level falls to or below 30
ppm. The BAQUACIL.RTM. sanitizer is added in an amount to achieve 50 ppm
of the sanitizer in the pool volume. Maintenance doses of oxidizer are
manually added in the amount of 128 oz oxidizer per 10,000 gallons pool
volume once per month. Maintenance doses of algicide are manually added
in the amount of 1.25 oz algicide per 10,000 gallons pool volume once per
week.
[0057] All pools are examined a minimum of three times per month. Water
samples are collected from each pool and tested for residual amounts of
sanitizer and oxidizer. Water balance parameters, water temperature and
turbidity, also are evaluated. The ppm levels of the oxidizer and the
sanitizer in the pool water are measured by using the PINPOINT.TM. Water
Analysis System Portable Lab from Avecia Inc. Turbidity is measured using
a Hach Corp. 2100P Turbidimeter. Algae and water clarity are evaluated
visually. The rating scales used for evaluation of algae and water
clarity are shown in Tables 1 and 2.
[0058] Evaluation of Residual Sanitizer Amount
[0059] Residual Sanitizer amounts are measured a minimum of three times
per month. Average residual sanitizer amounts are calculated for the test
pools and for the control pools. The average residual sanitizer amounts
for the test pools is 36.6.+-.6.0 ppm compared to an average of
36.0.+-.4.0 ppm for the control pools. This shows that maintenance doses
as calculated by the method of the invention as in Equations (1) and (2),
and which can be added in an automated manner, maintain amounts of
sanitizer in the test pools equivalent to levels achieved by following
weekly manual dosing to maintain a level of the sanitizer in an amount of
more than 30 ppm.
[0060] Evaluation of Algae Concentration
[0061] Visual assessment of the amount of algae present in a pool is
conducted a minimum of three times per month and assigned a rating
between 0 and 4. The rating scale used is shown in Table 1.
1TABLE 1
Rating Scale for Visual Assessment of
Algae
Rating Algae description
0 No trace of
visible algae anywhere in the pool
1 Trace amounts present on pool
sides or bottom
2 Small patches easily observed on pool sides and
bottom
3 Large patches easily observed on pool sides and bottom
4 25% or more of pool sides and bottom covered by algae
[0062] An acceptable algae rating is 1 or less. The algae rating reflects
the amount of algae present. A rating of "0" means there are no visible
signs of algae, whereas a rating of "4" means the pool is infested with
algae covering >25% of the visible pool surfaces or that the water
column is a solid green color due to planktonic algae. The percent of
pools that have acceptable algae ratings are listed in Table A.
2TABLE A
Algae Ratings Percentages
Percentage of Ratings Percentage of Ratings
System where the
ratings .ltoreq. 1 where the ratings > 1
Test pools
dosed with 89.0 11.0
the BAQUACIL AD .TM.
auto dosing
system
Control pools 75.0 25.0
[0063] As shown in Table A, the method of the invention provides superior
control of all three types of algae, including the target Chlorella spp.
(green algae) common to swimming pools.
[0064] Evaluation of Clarity and Turbidity Testing
[0065] A visual assessment of water clarity is conducted a minimum of
three times per month and assigned a water clarity rating between 0-4.
The clarity rating reflects the turbidity of the water. A rating of "0"
means the water is crystal clear, whereas a rating of "4" means the pool
is so cloudy that no real depth could be perceived. The rating scale used
to visually assess water clarity is listed in Table 2.
3TABLE 2
Rating Scale for Visual Assessment of
Water Clarity
Rating Water Clarity Description
0
Sparkling clear water
1 Water appears dull, slight haze present
2 Main drain is visible but not distinct
3 Bottom of shallow
end of visible, main drain is not
4 Cannot see bottom in the
shallow end
[0066] An acceptable clarity rating is 1 or less. The percent of pools
that have acceptable clarity rating readings are listed in Table B.
4TABLE B
Percent Acceptable and Unacceptable
Clarity Ratings
Acceptable Unacceptable
System Ratings
.ltoreq. 1 (%) Ratings > 1 (%)
Test pools dosed with
95.5 4.5
the BAQUACIL AD .TM.
auto dosing system
Control (Manually dosed) 75.0 25.0
[0067] Test pools that are treated with maintenance doses according to the
method of the invention have a much lower incidence of hazy water than
the control pools which are those dosed manually.
[0068] The average turbidity value for the test pools is 0.7 NTU
(Nephelometric Turbidity Units). This average turbidity value corresponds
to a haze rating of 0 and is excellent. In comparison, the average
turbidity value for the control pools that are not treated daily is much
higher at 1.1 NTU. The lower average turbidity for the test pools
correlates well with the visual assessment.
