Water treatment

Details Water treatment Water treatment

1999-07-30

2001-09-04

Simmons, David A. (Department: 1724)

Liquid purification or separation

Processes

Chemical treatment

C210S754000, C210S755000, C210S759000, C210S764000, C205S473000, C205S556000

Reexamination Certificate

active

06284144

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to the disinfection of water, and to the control of biofouling in clear and transparent water. In particular, the invention relates to the disinfection of salty swimming pool and mineral water, and the like water.
BACKGROUND OF THE INVENTION
Various methods for purifying water and for controlling the population level of biofouling and microorganisms have been disclosed. U.S. Pat. No. 5,662,940 relates to biocidal methods and compositions for recirculating the water system, comprising a hypochlorite donor and a bromide donor. This patent specifically relates to the disinfection of water in cooling towers, swimming pools and spas.
U.S. Pat. No. 5,424,032 describes a method of treating water using innocuous chemicals for the treatment of microorganisms.
The oxidizing biocide including free halogens, or hypohalites, or salts of hypohalites or hypohalite ion OX wherein X is Cl or Br, and halohydantoins such as bromochloro- or dibromodimethyl hydantoins or any oxidants which are used for disinfecting water.
When the treated water is salty water and mineral water, the disinfection agent causes a discoloration of the water which acquires a yellowish tinge, as well as a sensible turbidity thereof.
U.S. Pat. No. 4,385,973 relates to a process for disinfecting swimming pool water which comprises circulation with a pump by anodic oxidation in a reactor.
The use of anodic oxidation for the disinfection of liquids is known, for example, from U.S. Pat. No. 2,757,854, in which water that is to be disinfected is passed through a reactor which is provided with electrodes, and the water is treated electrochemically. The factors affecting the degree of disinfection are the electrical current density, the volumetric flow rate of the water, and the chloride content of the water.
It is customary to treat biologically contaminated water with one or more biocides to control the population of microorganisms in the water to prevent biofouling. Several factors play a role in the process: water pH, water temperature, aerobic/anaerobic conditions and salinity of the water. The particular types of microorganisms and the extent of microbial growth depend on the water source, and other factors.
It is a purpose of this invention to provide a process and composition for controlling biofouling and microorganism population levels in swimming pool waters, especially in salty swimming pools and salty mineral water.
It is another purpose of the invention to provide such a process and composition that have a high disinfecting effect, and to provide salty water which contains minerals, such as Fe
2+
, Mn
2+
, and Mg
2+
and other minerals, which is transparent and clear water.
Oxidizing biocides were found to be effective in salty water containing a concentration of oxidants much higher than usual, and when the hydrogen peroxide concentration is increased, the oxidants' effect is decreased.
Other elements which cause coloration of the water and turbidity in the presence of oxidants are used for disinfection.
SUMMARY OF THE INVENTION
This invention relates to the disinfection and purification of water. In particular, it relates to the disinfection and purification of swimming pool water, salty swimming pool and seawater, mineral water or the like water, for breeding fish and shellfish, etc.
The invention concerns methods and compositions for controlling biofouling and microorganism population levels in swimming pool or the like water, especially in salty mineral swimming pools. The process is performed in an electrolytic cell, controlled by redox electrode and recirculating water which contains peroxides such as hydrogen peroxide (H
2
O
2
) or Na
2
O
2
, in an amount sufficient to maintain redox buffer, and an oxidant, the oxidant including a halogenating chemical hypohalite species, which is chosen from among NaOCl, HOCl, NaOCl, NaOBr, HOBr, OBr
−
, OCl
−
, Br
2
, Cl
2
, acid solutions such as those containing (Cl
2
+HCl), (Br
2
+HBr), (Br
2
+HCl), trichlorocyanoric acid (TCCA), bromochlorodimethyl hydantoin (BCDMH), dibromodimethyl hydantoin (DBDMH), dichlorodimethyl hydantoin (DCDMH), and other halogen agents, etc., preferably an active chlorine donor or sodium hypochlorite (NaOCl) or hypohalide acid (HOX), such as hypochlorous acid (HOCl) or hypobromous acid (HOBr), or hypohalite ion OX, wherein X is Cl or Br, or halohydantoin, such as bromochloro- or dibromodimethyl hydantoin.
For this purpose, salty water which is to be disinfected is passed through an electroltyic cell or oxidant feeder which is fed into the water, and the water is treated by redox buffer, the term “redox buffer” meaning any compound that will keep the redox potential substantially constant in conditions which do not cause oxidation coloring elements, preferably about 300-410 mV. In a preferred form of the invention, the redox buffer is hydrogen peroxide (H
2
O
2
). When it is desired to treat, e.g., swimming pool water, the redox buffer and the subsequent oxidation has various beneficial effects; for instance, if the water is added and/or circulated in swimming pool and mineral water known to contain bacteriological and virological contaminants, which left untreated become a dangerous source of infection, this treatment helps in removing them. Additionally, it provides salty water which contains minerals, which is transparent and clear water, and prevents coloration and turbidity thereof.
Application of the method of the invention results in a considerable reduction of germ concentration in swimming pools, thus diminishing the risk of infection.
In a preferred form of the invention, when the pH of swimming pool water is typically regulated in the range of 7<pH<8 in salty water, hydrogen peroxide is added and the water is then treated electrochemically, or any other alternative way, the redox potential remaining constant in the range of 250-450 mV, preferably 300-410 mV, and H
2
O
2
at 0.001-1.0 ppm.
It is a purpose of the invention to provide a process and compositions for killing microorganisms and inhibiting biofouling in waters, especially salty waters, and which prevents the water turbidity, and coloration.


REFERENCES:
patent: 2757854 (1956-08-01), Wall
patent: 3719570 (1973-03-01), Lancy
patent: 4385973 (1983-05-01), Reis et al.
patent: 4966775 (1990-10-01), Donofrio et al.
patent: 5424032 (1995-06-01), Christensen et al.
patent: 5575945 (1996-11-01), Perlman
patent: 5662940 (1997-09-01), Hight et al.
patent: 5683724 (1997-11-01), Hei et al.
patent: 5783092 (1998-07-01), Brown et al.
patent: 5851407 (1998-12-01), Bowman et al.
patent: 5882526 (1999-03-01), Brown et al.
patent: 0 403 465 B1 (1990-12-01), None
patent: 0 403 465 A1 (1990-12-01), None
patent: 0 517 102 A1 (1992-12-01), None
Campo et al.; “Catalytic Oxidation in Natural Water”, CA 104(95133Y) p. 421 (1986).
Dodonov et al.; Prevention of Biological Fouling of Heat Exchangers by Iron Metabolizing Bacteria, C A vol. 115(166275m).
Matson, et al.; “Biocidal Methods and Composition for Recirculating Water Systems”, C A vol. 114 (17993 r) p. 427 (1991).
Fraser J. A. L.; “Peroxygens in Environmental Protection”, C A vol. 105(84492j) p. 361 (1986).

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