Chemical apparatus and process disinfecting – deodorizing – preser – Process disinfecting – preserving – deodorizing – or sterilizing – Using disinfecting or sterilizing substance
Reexamination Certificate
1995-04-13
2002-02-26
Thornton, Krisanne (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Process disinfecting, preserving, deodorizing, or sterilizing
Using disinfecting or sterilizing substance
C210S764000, C252S175000, C252S178000, C252S181000, C422S019000, C422S028000, C424S641000, C514S494000
Reexamination Certificate
active
06350410
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method and composition for inhibiting biological fouling in an irrigation system, and more particularly, to a method and composition which include the addition of zinc to water in an irrigation system.
BACKGROUND INFORMATION
Irrigation water is often pumped from a source, such as a pond, through an irrigation system to crops or orchards. Due to impurities in the source water, biological fouling may occur in the irrigation system. The biological fouling can develop buildups in the irrigation system, resulting in a loss of flow rate through the irrigation system. This problem is exacerbated by the common use of black polyethylene material for lines in irrigation systems, which tends to absorb heat, resulting in a proliferation of biological fouling. In addition, there is a trend toward irrigation systems designed to conserve water which have lower flow rates passing through the systems. These lower flow rate irrigation systems are prone to buildups of biological fouling since impurities are not as likely to be flushed from the system.
Currently, in order to maintain free flowing irrigation lines and emitters, an irrigation system is flushed with an excess of chlorine before and after the growing season. Generally, this process cannot be performed during the growing season since excess levels of chlorine may be toxic to plants.
Zinc is an essential element to normal plant growth and physiology. Typically in commercial farming, zinc is fed to plants in very large levels once or twice during a growing season. The zinc may be fed as a liquid concentrate containing active zinc in amounts as high as 100,000 ppm. High concentrations of zinc may also be fed in a dry form directly to the soil. Often, the concentrated zinc is applied by aerial application. This current practice of feeding high concentrations of zinc once or twice during a growing season can be potentially toxic to certain plants as well, as pose an environmental risk of run off to lakes and rivers.
DISCLOSURE OF THE INVENTION
The present invention provides a method for treating an irrigation system to inhibit the formation of biological fouling. The method includes providing water, admixing with the water an effective amount of active zinc, and pumping the water admixed with the active zinc through irrigation lines and emitters in the irrigation system to inhibit biological fouling. The active zinc is admixed with the water in an amount sufficient to inhibit the growth of biological fouling in the irrigation lines and emitters through which the water is pumped. The active zinc may be provided by zinc sulfate.
In a preferred form of the invention, the effective amount of active zinc is between about 0.1 ppm to about 10.0 ppm. In an even more preferred form of the invention, the effective amount of active zinc is between about 0.1 ppm to about 1.0 ppm.
The method of the present invention may be performed on a continual basis by repeating the step of admixing with the water an effective amount of active zinc and the step of pumping the water admixed with the active zinc through the irrigation system each time irrigation water is pumped through the system. For practicing this invention on a continual basis, it is preferred that the effective amount of active zinc is between about 0.1 ppm to about 1.0 ppm.
The method of the present invention may also be performed on a periodic basis by repeating the step of admixing with the water an effective amount of active zinc and the step of pumping the water admixed with the active zinc through the irrigation system at least one time each week when irrigation water is pumped through the system. For practicing this invention on a periodic basis, it is preferred that the effective amount of active zinc is about 10.0 ppm.
In another form of the invention, the zinc is chelated with 1-hydroxyethane 1,1-diphosphonic acid (HEDPA). In a preferred form, the zinc is chelated with HEDPA on a 1:1 molar ratio.
The present invention also provides a composition for use in an irrigation system for inhibiting biological fouling in irrigation lines and emitters in the irrigation system. The composition comprises water and active zinc. The active zinc is present in the composition in an amount sufficient to inhibit biological fouling in irrigation lines and emitters such that following pumping of the composition through an irrigation system, biological fouling is inhibited in the irrigation lines and emitters. The active zinc may be provided by zinc sulfate.
In a preferred form of the invention, the composition includes active zinc in an amount between about 0.1 ppm to about 10.0 ppm. In an even more preferred form of the invention, the active zinc is present in an amount between about 0.1 ppm and 1.0 ppm.
The composition may further include 1-hydroxyethane 1,1-diphosphonic acid (HEDPA) in an amount to chelate the active zinc. Preferably, the HEDPA is present in an amount to chelate the active zinc on a 1:1 molar ratio.
These and other advantages and features will become apparent from the detailed description of the best mode for carrying out the invention that follows.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention provides a method and composition for affecting biological fouling in an irrigation system. It has been discovered that the addition of an effective amount of active zinc to irrigation water passing through an irrigation system reduces biological fouling in the system. With decreased amounts of biological fouling in the irrigation system, irrigation lines and emitters in the system remain free flowing.
Herein, biological fouling refers to bacterial and algal growth. Such bacterial growth includes the bacteria crenothrix polyspora which is commonly found in source water and tends to cause slime growth in irrigation systems.
Active zinc for use in the present invention may be in the form of zinc sulfate. The active zinc acts as a biocide in the irrigation system to inhibit the growth of biological fouling which is detrimental to the irrigation system. In addition, the zinc is present in the water exiting the irrigation emitters onto crops or orchards. These low levels of zinc are an essential element to normal plant growth and physiology. Plants are nourished by these low levels of zinc feeding, eliminating the need for high concentrations of zinc feeding once or twice during the growing season.
Preferably, the zinc is admixed with the irrigation water at the head of the irrigation system with a metering pump. Alternatively, the zinc may be fed at satellite feed stations throughout the irrigation system. Generally, irrigation systems have flow rates through the main lines as high as eighty gallons per minute and flow rates through secondary lines as low as one half to one gallon per hour, particularly in drip irrigation systems. It is preferred that the active zinc is present in the irrigation water at about 0.1 to about 10.0 ppm. According to the present invention, the amount of active zinc may be above 10.0 ppm so long as the active zinc is not at levels which are toxic to the plants being irrigated. However, goods results have been obtained with active zinc in the irrigation water between about 0.1 and about 10.0 ppm and increased levels may do little more than add to the cost of performing this invention.
The active zinc may be fed into the irrigation water on a continual basis such that each time an irrigation system provides irrigation water to a crop or an orchard, active zinc is present in the irrigation water. If the present invention is practiced on a continual basis, it is preferred that the active zinc be present in an amount between about 0.1 and about 1.0 ppm. These low levels of active zinc inhibit biological fouling in the irrigation system and provide slow feeding of active zinc to plants being irrigated.
Alternatively, the active zinc may be fed into the irrigation water on a periodic basis such that active zinc is only admixed with the irrigation water passing through the system part of the time that irrigation water
Iverson Carl E.
Prindle Joyce
Barnard Delbert J.
CH20 Incorporated
Thornton Krisanne
LandOfFree
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