Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
2000-09-22
2002-03-05
Simmons, David A. (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
C210S623000, C210S629000, C210S630000, C210S195300, C210S197000, C210S221200, C210S259000, C210S528000
Reexamination Certificate
active
06352643
ABSTRACT:
TECHNICAL FILED
Be present invention relates to a wastewater treatment plant comprising an upflow anaerobic reactor and to a wastewater treatment method using thereof. More specifically, the present invention relates to a wastewater treatment plant which comprises the facultative bacteria and an anaerobic reactor, and also relates to a method for wastewater treatment using thereof. By using the present invention, the organic wastewater containing non-biodegradable and toxic matter, nutrients (N, P), and heavy metals can be treated in a stable manner; the sludge treatment cost can be reduced by keeping a high concentration of sludge; and the land usage for the facilities, the costs for construction and operation can be much saved by using the preinstalled settling tank as a reactor.
BACKGROUND ART
Generally, a wastewater contains nutrients such as nitrogen or phosphor, non-biodegradable and toxic matter, and heavy metals. The treatment methods for clarifying such wastewater can be generally classified into the biological method or treatment of the wastewater containing organic compounds, and the physicochemical method for treatment of the wastewater having non-biodegradable and toxic matter and heavy metals therein.
To repeat, for removal of organic matters, the biological method is in the most common use among the above treatment methods. As a representative of the biological treatments, there is an activated sludge method that employs a treatment plant consisting of an initial settling tank, an aeration tank, and a terminal-settling tank. In this case, however, a thickening tank is indispensably required for the post-treatment process of the sludge since the sludge concentration in the settling tank is as low as 5000~15000 mg/L, and further, the efficiency decline is inevitably invited in the terminal settling tank if under the low concentration of the sludge, for the aeration tank is run with 1500~3000 mg/L of the sludge concentration during the operation. Moreover, in the activated sludge method, there has often been the sludge-bulking phenomenon by the variation of quality and amount of the influent water, with the result of process failure or water quality deterioration.
Another biological method for releasing nitrogen or phosphor is one employing the anaerobic•aerobic method, in which an aerobic reactor provided with oxygen thereinto and an anaerobic reactor without the supply of oxygen are arranged in a row for operation in the conventional activated sludge method, and thereby, nitrogen and phosphor can be removed by means of the action of the microorganisms. However, since this method employs a complete-mixing type of reactor, it is difficult to retain high concentration of the microorganisms in the reactor and a complete anaerobic atmosphere can hardly be kept during denitration or in the guidance of phosphor effluence. Such points as these have often served as restrictions in designing a reactor and brought about the problem of complicated operation.
In order to treat the wastewater containing non-biodegradable and toxic matter and heavy metals, it is common to employ a biological method added to the physicochemical treatment method. However, such physicochemical methods suffer from a drawback in that the operation cost is increased due to the great amount of consumption of the chemicals for adsorption or oxidation. Further, the biological treatment associated with these physicochemical methods, in terms of practical use, is in its early stage; a secondary treatment is indispensably required for elimination of the intermediate products of heavy toxicity which are produced during the initial treatment process; the operation cost is inevitably increased in the anaerobic treatment because of the necessity of temperature retention.
To sum up, the organic wastewater containing heavy metals has been clarified by using the physicochemical treatment method in the main, but in recent years, a biological treatment method using the sulfate-reducing bacteria has newly been on the rise. In this method, however, there is a defect that the operation cost is increased due to the temperature retention, since the sulfate-reducing bacteria, on account of its nature, must be grown in a rigorous anaerobic atmosphere.
In conclusion, a more efficient and economic method for treatment of wastewater has been wanted, in which such problems as inherent to the conventional physicochemical and biological methods for treatment of the organic wastewater containing non-biodegradable and toxic matter, nutrients such as nitrogen or phosphor, and heavy metals, viz., the problems in that the cost for treatment is unduly increased, the degree of clarification has not reached completion as yet, and a secondary treatment is necessary due to the production of intermediate products, can all be remedied.
The inventors of the present invention have unceasingly endeavored with studying and doing a lot of research for solving the problems of the prior art, to finally confirm that by using the wastewater treatment plant which comprises an upflow anaerobic reactor having the improved introducing means and discharging means, and combined with the conventional aerobic reactor and settling tank, the organic wastewater containing non-biodegradable and toxic matter, nutrients such as nitrogen or phosphor, and heavy metals can successfully be treated, resulting in a greatly improved clarification efficiency. To this end, the inventors have finally accomplished the present invention.
Ultimately, it is the main object of the present invention to provide a wastewater treatment plant comprising an upflow anaerobic reactor.
Another object of the present invention is providing of a wastewater treatment method using said wastewater treatment plant.
SUMMARY OF THE INVENTION
Below, the configuration of the wastewater treatment plant comprising an upflow anaerobic reactor according to the present invention is described in more detail.
With respect to the wastewater treatment plant consisting of an anaerobic reactor, an aerobic reactor, and a terminal settling tank, the present invention is characterized in that said anaerobic reactor comprises an inlet mounted at the external lowest region of the anaerobic reactor; an introducing means which is directly connected to said inlet but is located inside of the anaerobic reactor at the lower part, and has a perforated drain pipe therein; the mixing means which is installed at the main shaft thereof at a regular interval in the anaerobic reactor; a discharging means which has the radial-shaped weirs extending outwards from the center and is provided at the upper region in the anaerobic reactor for allowing the reaction water which comes to contain some portion of the sludge in the reaction generated by said mixing means, to flow into the aerobic reactor, a sludge-accumulating means which is situated at the lower region in the anaerobic reactor and collects the sludge at the center in the anaerobic reactor, said sludge being settled by the gravity force during said reaction by the mixing means.
As one embodiment of the present invention, a wastewater treatment plant employing the upflow anaerobic reactor according to the present invention is described hereinbelow with reference to
FIG. 1
a.
First of all, as aforementioned, the upflow anaerobic reactor (
10
) comprises an inlet (
11
), an introducing means (
12
), a discharging means (
13
), a mixing means (
14
), and a sludge-accumulating means (
15
).
Of these constituents, the inlet (
11
) is installed at the external lowest region of the anaerobic reactor (
10
) in order to introduce both the influent water and the sludge into the anaerobic reactor (
10
), said sludge having been returned from the terminal settling tank (
30
) by the actuation force of the sludge-returning pump (
50
). Such inlet (
11
) is integrated into a single channel before the introducing means (
12
) in order for the influent water to be mixed with the return sludge prior to flowing into the anaerobic reactor.
Next, the introducing means (
12
), direct
Bae Byung-Uk
Kwon Joong-Chun
Shin Hang-Sik
Yoo Kyu-Seon
Lahive & Cockfield LLP
Prince Fred
Simmons David A.
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