Liquid purification or separation – Processes – Chemical treatment
Reexamination Certificate
1996-08-30
2002-07-16
Woo, Jay H. (Department: 1724)
Liquid purification or separation
Processes
Chemical treatment
C210S716000, C210S724000, C210S726000, C210S754000, C252S175000, C252S181000, C405S128350, C405S263000
Reexamination Certificate
active
06419836
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns a composition for treatment of water, especially standing bodies of water and drinking water, for example, drinking water produced by water treatment plants and for reconditioning of acidic soils.
The preparation of drinking water and purification of bodies of water present an ever-increasing problem in an industrial society. Acidification of waters, meaning that the pH value of the water drops as a result of acidic tributaries, acid rain or through the influx of acidic components of the soil, is a well known problem. The natural pH balance of the body of water is disturbed by the low pH, and additionally, heavy metal salts are quite soluble at lower pH, whereby the content of heavy metal salts known to have detrimental effects on living organisms is greatly increased. Moreover, metal water pipes can be dissolved at low pH values. Overall, a drastic reduction or, respectively, a drastic increase in the pH value of waters, especially standing bodies of water, leads to a decrease in the ability of the water to clean and regenerate itself, and finally to a gradual degeneration and death.
A further problem is that acidic waters frequently suffer from an insufficient lime content, a condition which results in further weakening of the biological activity of waters.
Furthermore, drinking water with a pH which is too high, or too low, respectively, and an insufficient content of lime can lead to health problems.
Frequently, drinking water which is prepared by utilization of conventional water treatment facilities does not conform to the standards set by law for pH value, lime content and buffer capacity and thus cannot be released for use by the consumer. According to legal standards, drinking water should have a pH of between 6.5 and 9.5.
Lime, CaCO
3
, is traditionally used to increase the pH value and lime content of acidic waters. Studies have shown, however, that lime settles as a layer on the bottom of the body of water and, in this form, does not have the desired effect of raising the pH.
In the case of strongly acidic waters, especially those that suffer from having acidic industrial waste waters fed into them, NaOH is used occasionally as well. The addition of NaOH only neutralizes the water, however, and causes no improvement in the water hardness or the buffer capacity so that no real positive stimulation of the water is brought about.
A further means which is used to raise the pH value of waters and/or soils is the use of Na
2
CO
3
, soda. The addition of soda leads to a short-term success. It does not contribute to an increase in hardness. The risk of damage to organism-bearing sediments due to local over-alkalization is great, however.
The object of the present invention is to provide a composition which makes it possible to effect long-term rejuvenation of strongly acidic or, respectively, strongly alkaline waters and soils, especially with respect to providing a stable pH value in the range between 6.5 and 9.5 together with a sufficient hardness.
SUMMARY OF THE INVENTION
The composition for treatment of water and soils according to the present invention is primarily characterized by comprising components:
A. CaCO
3
,
B. at least one compound selected from the group consisting of calcium salts, including CaCl
2
and Ca(NO
3
)
2
, and inorganic magnesium compounds,
C. at least one compound selected from the group consisting of NaHCO
3
and KHCO
3
,
wherein the components A and B are present in a molar ratio of from 0.1:1 to 2:1, and
wherein the components B and C are present in a molar ratio of from 1:3 to 2:1.
Preferably, the inorganic magnesium compounds include chloride, nitrate, carbonate, oxide, and sulfate, and the calcium salts and inorganic magnesium compounds are used in a molar ratio of from 0.8:1 to 10:1.
The calcium salts and inorganic magnesium compounds are expediently used in a molar ratio of from 1:1 to 6:1.
The components A and B are present in a molar ratio of from 1:1.3 to 1.3:1.
The components A and B are present in a molar ratio of from 1:1.3 to 1:2.
The component C preferably comprises NaHCO
3
and KHCO
3
in a molar ratio of from 10:1 to 1:1.
The component A further may comprise up to 25 weight-% MgCO
3
.
The inventive composition may further comprise Na
2
CO
3
in an amount of up to 20% of a molar amount of the component C.
The present invention also concerns a method for treatment of water to be treated comprising the steps of:
a) dissolving at least one compound selected from the group consisting of calcium salts, including CaCl
2
and Ca(NO
3
)
2
, and inorganic magnesium compounds in H
2
O to form a first aqueous solution,
b) dissolving separately at least one compound selected from the group consisting of NaHCO
3
and KHCO
3
in H
2
O to form a second aqueous solution,
c) mixing the first and second aqueous solutions with the water to be treated to form a mixture, and
d) passing the mixture of step c) over CaCO
3
.
Step d) preferably includes the step of providing CaCO
3
as a solid bed.
The invention also relates to a method of treating acidic and alkaline water to be treated, including drinking water and standing bodies of water, said method comprising the steps of:
preparing a composition comprising:
A. CaCO
3
,
B. at least one compound selected from the group consisting of calcium salts, including CaCl
2
and Ca(NO
3
)
2
, and inorganic magnesium compounds,
C. at least one compound selected from the group consisting of NaHCO
3
and KHCO
3
,
wherein the components A and B are present in a molar ratio of from 0.1:1 to 2:1, and
wherein the components B and C are present in a molar ratio of from 1:3 to 2:1; and
adding the composition to the water to be treated.
The invention also relates to a method of treating soils to be treated, including acidic forest soils, said method comprising the steps of:
preparing a composition comprising:
A. CaCO
3
,
B. at least one compound selected from the group consisting of calcium salts, including CaCl
2
and Ca(NO
3
)
2
, and inorganic magnesium compounds,
C. at least one compound selected from the group consisting of NaHCO
3
and KHCO
3
,
wherein the components A and B are present in a molar ratio of from 0.1:1 to 2:1, and
wherein the components B and C are present in a molar ratio of from 1:3 to 2:1; and
adding the composition to the soils to be treated.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention thus provides a composition for treatment of water and reconditioning of soils, comprising
A. CaCO
3
,
B. CaCl
2
and/or Ca(NO
3
)
2
and, optionally, magnesium salts
C. NaHCO
3
and, optionally, KHCO
3
whereby components A and B are present in a molar ratio of from 0.1:1 to 2:1 and components B and C are present in a molar ratio of from 1:3 to 2:1.
Surprisingly, it has been found that through use of the composition of the present invention in conjunction with waters as well as soils, a stable pH value of between 6.5 and 9.5 is achieved, while at the same time the lime content is increased and a stable buffer capacity is provided. In general, and even in cases of strongly acidified waters, use of the composition of the present invention resulted in a significant increase in the microbiological activity of the water, even after just a few days. This was even more surprising in view of the fact that component B, namely CaCl
2
or Ca(NO
3
)
2
and optional magnesium salts, are themselves acidic when dissolved in water. It was also surprising that use of the composition reduces the pH value of high pH waters and, in spite of this, the water hardness and the buffer capacity with respect to acids increases. It was also determined that metals largely precipitate and that colloidally suspended particles are entrapped in this process as well. Further, it was also observed that aggregates of humic acids were formed, whereby the effect of these acids with respect to mobilization of metals was decreased.
The components of the present invention can all be obtained commercially, the grades or qualities thus available being suitable for the invention.
Becker R. W.
Morrison Betsey J.
R.W. Becker & Associates
Söl Peter
Woo Jay H.
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