Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
1999-03-23
2001-05-08
Simmons, David A. (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
C210S620000, C210S630000, C210S631000, C210S712000, C210S151000, C210S195300, C210S199000, C210S205000, C210S915000, C423S24000R, C423SDIG001
Reexamination Certificate
active
06228267
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to waste water treatment equipment and waste water treatment method capable of concurrently treating an exhaust gas containing fluorine and organic matter when treating a waste water that contains fluorine and organic matter or contains fluorine, organic matter and hydrogen peroxide.
Conventionally, the waste water that contains fluorine and organic matter or contains fluorine, organic matter and hydrogen peroxide discharged from various kinds of industrial facilities, semiconductor plants and so on (the water referred to as waste water hereinafter) has generally been treated separately by waste water treatment equipment and exhaust gas treatment equipment.
That is, with regard to the fluorine in the waste. water, slightly-soluble calcium fluoride is generated principally by incorporating a large amount of slaked lime into the waste water and is precipitated for the removal of the fluorine. The organic matter such as a surfactant and an organic solvent in the waste water have been treated after the treatment of fluorine by performing biological treatment with a nutrition put in a treatment water tank different from that of the treatment of fluorine or by means of an activated carbon adsorption in a case where the organic matter concentration is low.
On the other hand, the fluorine in the exhaust gas has been treated by exhaust gas treatment equipment represented by an acid scrubber, while the organic matter such as the organic solvent in the exhaust gas has been treated by exhaust gas treatment equipment (specifically, an activated carbon adsorption filter unit) stowed with activated carbon. As a representative of the organic matter in the exhaust gas, there can be enumerated organic solvent such as acetone and isopropyl alcohol. Then, the organic solvent is generally treated by adsorption with the activated carbon adsorption unit.
Generally in the activated carbon adsorption filter unit, there are provided two or more activated carbon filters, which alternately repeat adsorption and desorption to continuously treat the organic solvent by adsorption. However, the activated carbon adsorption filter unit does not decompose the organic solvent itself, and therefore, the total amount of the organic solvent itself does not vary.
Furthermore, the existing semiconductor plants and liquid crystal plants are frequently subjected to redevelopment by facility renewal, and there is frequently occurring the phenomenon that the originally planned capability of the exhaust gas treatment equipment becomes insufficient. The reason of the insufficiency of the exhaust gas treatment equipment capability is that the greater number of production units than originally planned tend to be installed and the flow rate of the exhaust gas to be treated in using the production units increases with the introduction of a new production unit.
In contrast to this, the prior art exhaust gas treatment equipment is hard to increase its treatment capability by modifying the aforementioned units after being once installed. Therefore, in order to improve the exhaust gas treatment capability, it is required to newly install additional exhaust gas treatment equipment.
However, newly installing the additional exhaust gas treatment equipment is often difficult in terms of plan from the viewpoint of the initial cost and space.
Therefore, the insufficiency of the exhaust gas treatment capability has hindered the smooth renewal of the production facilities in the semiconductor plants and the liquid crystal plants.
On the other hand, in regard to the influence on the waste water treatment equipment, with the current trend toward the removal of Fleon, in particular, cleaning methods by combinations of a variety of surfactants, acetone, alcohol and so on instead of Fleon for cleaning use in the semiconductor plants and liquid crystal plants are expected as important cleaning methods for the total abolition of Fleon, judging from the their good cleaning performances and small damages on components.
However, the implementation of the cleaning method by a combination of ultrapure water and a surfactant or a variety of acids has the problem that calcium fluoride waste extremely increases with respect to, in particular, the fluorine treatment in the above plants and the problem that the remaining surfactant influences the water quality of the treated water.
Furthermore, the surfactant, which sometimes have a sterilizing effect on the microorganisms utilized for waste water treatment, makes it difficult to perform microorganic treatment.
In view of the aforementioned problems of the prior art waste water treatment technique, there is proposed improved treatment equipment and treatment method as shown, in
FIG. 13
(refer to the prior art reference of Japanese Patent Laid-Open Publication No. HEI 8-57498) for concurrently treating a waste water containing fluorine and organic matter and an exhaust gas containing fluorine and organic matter.
In
FIG. 13
, the reference numeral
101
denotes a first reaction equalizing tank. A first lower section
101
a
of this first reaction equalizing tank
101
is stowed with calcium carbonate mineral
109
A stowed in a stowing basket
110
A. The first reaction equalizing tank
101
has a blower
117
, a pipe
120
A extending from this blower
117
and a diffuser pipe
111
A provided at the end of this pipe
120
A. The diffuser pipe
111
A is arranged at the bottom of the first lower section
101
a
of the first reaction equalizing tank
101
while constituting an aerating means.
The waste water that contains fluorine and organic matter and is discharged from the production process is first introduced into the first reaction equalizing tank
101
.
The water level of the waste water inside the first reaction equalizing tank
101
is adjusted so that the calcium carbonate mineral
109
A is submerged. The waste water is strongly stirred by the aerating means. Due to this stirring, the fluorine ion in the waste water and calcium ion dissolving from the calcium carbonate mineral
109
A react each other with the lapse of time. In this case, acids such as hydrofluoric acid and sulfuric acid are mixed in the waste water, so that the waste water exhibits acidity. Therefore, calcium tends to easily dissolve from the calcium carbonate mineral
109
A. Accordingly, crystalline calcium fluoride (crystal seed) is easily generated.
In a first upper section
101
b
of the first reaction equalizing tank
101
is arranged a first reaction water sprinkling section
103
stowed with the calcium carbonate mineral
109
A and a plastic filler
113
A.
Then, in a space S
1
leading the exhaust gas and being located below the first reaction water sprinkling section
103
is provided a duct
129
that communicates with this space S
1
and is projecting sideways. The end of this duct
129
is mounted with a ventilation fan
112
, and this ventilation fan
112
allows the exhaust gas containing fluorine and organic matter from the plant to be led into the space S
1
.
In a lowermost portion of the first reaction water sprinkling section
103
is provided a grid plate
115
A. As shown in
FIG. 13
, this grid plate
115
A has its grid extending in the vertical direction, so that the projected area in the vertical direction is made much smaller than the projected area in the lateral direction. Therefore, the exhaust gas from the duct
129
can easily pass through the grid plate
115
A and reach the first reaction water sprinkling section
103
.
Then, the exhaust gas whose fluorine has been treated while passing through the first reaction water sprinkling section
103
from the lower side to the upper side, i.e., the treated gas is introduced into an exhaust gas introducing space S
2
below a second reaction water sprinkling section
104
provided in a second upper section
102
b
of a second reaction equalizing tank
102
by way of a duct
121
connected to the uppermost portion of the first reaction equalizing tank
101
.
The second reaction equalizing tank
102
is stowe
Fujimoto Teruhiko
Matsumoto Shigeki
Ogimoto Takashi
Takahashi Tsuyoshi
Tanaka Noriyuki
Nixon & Vanderhye P.C.
Prince Fred
Sharp Kabushiki Kaisha
Simmons David A.
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