Chemistry: molecular biology and microbiology – Apparatus – Bioreactor
Reexamination Certificate
2001-06-22
2003-04-29
Redding, David A. (Department: 1744)
Chemistry: molecular biology and microbiology
Apparatus
Bioreactor
C435S266000, C435S299100, C055S492000, C055S495000
Reexamination Certificate
active
06555364
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a Biological deodorizing apparatus assembled with box-like frame units, especially to a deodorizing apparatus which can be easily constructed in suitable size according to amount and characteristics of gas to be treated and space where to be installed.
2. Prior Art
Typical malodorous materials causes at a sewage treatment place are these three types, ammonia, hydrogen sulfide, and organic sulfuric compound (methyl mercaptane, methyl sulfide, methyl disulfide), and objective of deodorizing is to reduce these malodorous materials to the density where they are not perceived as odor.
In Japan, threshold densities and regulation bases are stated for 22 types of material in prevent odor low by the ministry of environment. Regarding to odor causes at a sewage treatment place, hydrogen sulfide, methyl mercaptane, methyl sulfide, methyl disulfide, ammonia, and trimetylamine, are mainly considered, so that designing targets of a deodorizing apparatus are settled at those 6 materials. However, in practice, trimetylamine is hardly detected and designing targets are settled at rest 5 materials.
Odor is multiple smell of these 5 materials, and removing odor means reducing these 5 materials to the density where they are not perceived as odor.
Because the extent of odor deeply relates to the sensing level of human (threshold), threshold densities and regulation bases for 5 material are stated in prevent odor low by the ministry of environment as shown in below table. 1.
TABLE 1
(ppm)
Odor
Hydrogen
Methyl
Methyl
Methyl
intensity
sulfide
mercaptane
sulfide
disulfide
Ammonia
1
0.0005
0.0001
0.0001
0.0003
0.1
2
0.006
0.0007
0.002
0.003
0.6
2.5
0.02
0.002
0.01
0.009
1
3
0.06
0.004
0.05
0.03
2
3.5
0.2
0.01
0.2
0.1
5
4
0.7
0.03
0.8
0.3
10
5
8
0.2
2
3
40
The odor intensity is described as follow.
1—Smell which can be perceived with difficulty (sensing threshold.)
2—Tiny smell which can be distinguished as what smell is (recognizing threshold.)
2.5—To make the density below the value shown in above table become regulated base in residential area.
3—Smell which can be perceived easily.
3.5—To make the density below the value shown in above table become regulated base in industrial area.
4—Strong smell.
5—heavy smell.
The odor intensity 2.5 regulated as base in residential corresponds to odor density
300
(density which can't be perceived by being diluted to 300 times of volume). Though the odor intensity
4
and
5
is out of question because of being awful odor, in the case where odor intensity exceeds 3, a complaint about odor is always made by residents. Therefore, the deodorizing apparatus is required having capacity to remove the smell to the level below smell intensity 2.5.
At the present time, ordinary methods used for deodorizing apparatuses installed at sewage treatment places are washing by liquid chemicals and absorbing by activated carbon, then these methods have left a lot of results and been evaluated properly. However these two methods have some problems as described below.
(1)The Method of Washing by Liquid Chemicals
The method of washing by liquid chemicals requires daily maintenance of medical density of washing liquid and has many problems about maintenance such that solid material (blocking material) suddenly causes in abnormal reaction between odor material and liquid chemicals in the case where the maintenance is failed. Ordinary, as seen that activated carbon devices are always installed (follows as later treating) behind the method of washing by liquid chemicals, it is guessed that the method of washing by liquid chemicals is low reliable and unstable. Further, demand of liquid chemicals increases in proportional to gas amount and odor material density, and maintenance cost is not negligible. Furthermore, in the method of washing by liquid chemicals, because portion of washing recycling liquid must be replaced, there is a problem that treatment of replaced waste liquid including the replaced liquid chemicals must be considered as a part of equipment.
(2) The Method of Absorbing by Activated Carbon
On the other hand, the method of absorbing by activated carbon is suitable for deodorizing low density odor. However, because it absorbs odor physically, all of activated carbon must be replaced with new one when it is saturated. The cost also, similar to the liquid chemicals, increases in proportional to the gas amount and the odor material density, and the maintenance cost becomes heavy burden.
(3) The Method of Biological Deodorizing
These years, research and development about biological deodorizing uses physiological function of absorbing malodorous materials by living organisms are prosperous, and it is verified by actual apparatus that living organisms are superior to remove malodorous materials such as hydrogen sulfide or organic sulfuric compounds cause at the sewage treatment place. Then it is to be recognized that the biological deodorizing is effective.
Comparing to the conventional methods of washing by liquid chemicals or absorbing by activated carbon, the deodorizing apparatus applying physiological metabolism by which microorganisms absorb malodorous materials does not require cost for chemicals and activated carbon either cost for maintenance such as labors cost for supplying medical liquid or replacing activated carbon, and is maintenance free and environmentally harmless apparatus. Further, comparing to the methods of washing by liquid chemicals and absorbing by activated carbon being inferior to treat high density gas, the microorganisms can work well in high density, and naturally be expected to be alternative. Deodorizing in future is, in spite of density or amount of treating gas, seems to be entrusted to biological deodorizing one by one at all.
However, deodorizing rate of living organism is extremely slower than washing by liquid chemicals or absorbing by activated carbon and the apparatus needs to be 2.5 times as large as washing by liquid chemicals or 1.5 times as large as activated carbon device. Most of current apparatus is sized at each of designing according to treating gas amount and odor material density, and then constructed by hand at the construction site.
Ordinary, deodorizing apparatus is installed indoors. Because normal height under beam of sewer equipment is 6.5 m in Japan (about 7 m in Western countries), height of apparatus must be in range where washing nozzle set on topside can be inspected without difficulty.
Recently, without installing several apparatuses at each section divided by each source, high and low range density gas tend to be mixed and treated at the same time. Then large capacity of range from 500 m3/min to 1000 m3/min is started to be in demand. Such a situation causes problem of impossibility of installing in space for conventional biological deodorizing apparatus having capacity of about 200 m3/min. Further, there is another problem that the deodorizing apparatus using living organism requires long culturing term to bring its ability into full work.
A gas-flow-in area (frontage×height) is widen to meet increase of treating amount. In the case where gas density goes high, number of deodorizing units is increased and apparatus becomes longer. No one raise an objection to the fact that running cost for biological deodorizing is less than one tenth of the cost for washing by liquid chemicals or activated carbon device, and it is ideal apparatus without the maintenance trouble nor the pollution problem. Then problems mentioned above are expected to be solved. Though an apparatus is evaluated by products cost and running cost, the objective of present invention is to provide an apparatus which can be constructed in size fits for limited space and whose cost is also low.
SUMMARY OF THE INVENTION
The biological deodorizing apparatus assembled with box-like frame units of the present invention has an inlet portion of malodorous gas, a treating portion and an outlet portion in a series, and relates to a deodorizing apparatus which biologically
Koda & Androlia
Redding David A.
Sankyo Kogyo Co., Ltd.
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