CA1216810A - Process and equipment for purifying waste air - Google Patents
Process and equipment for purifying waste airInfo
- Publication number
- CA1216810A CA1216810A CA000427789A CA427789A CA1216810A CA 1216810 A CA1216810 A CA 1216810A CA 000427789 A CA000427789 A CA 000427789A CA 427789 A CA427789 A CA 427789A CA 1216810 A CA1216810 A CA 1216810A
- Authority
- CA
- Canada
- Prior art keywords
- packing material
- water
- air
- wash water
- microbiological
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
- B01D47/14—Packed scrubbers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/84—Biological processes
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/025—Biological purification using sources of oxygen other than air, oxygen or ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/04—Aerobic processes using trickle filters
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/10—Packings; Fillings; Grids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/30—Details relating to random packing elements
- B01J2219/302—Basic shape of the elements
- B01J2219/30215—Toroid or ring
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Biodiversity & Conservation Biology (AREA)
- Organic Chemistry (AREA)
- Microbiology (AREA)
- Health & Medical Sciences (AREA)
- Water Supply & Treatment (AREA)
- Hydrology & Water Resources (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biomedical Technology (AREA)
- Molecular Biology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- General Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Treating Waste Gases (AREA)
- Biological Treatment Of Waste Water (AREA)
- Gas Separation By Absorption (AREA)
- Cleaning Or Drying Semiconductors (AREA)
- Exhaust Gas After Treatment (AREA)
- Electrostatic Separation (AREA)
Abstract
MICROBIOLOGICAL PACKING MATERIAL FOR BIO-SCRUBBER
ABSTRACT OF THE DISCLOSURE
A method and apparatus are provided for purifying air or other gaseous oxygen-containing effluent having microbiologically decomposable or biodegradable con-taminants therein. The above is accomplished by providing an array or permeable mass of packing material with colonies of microorganisms growing thereon. The packing material and/or the air to be purified is sprayed with water to dissolve out the water soluble impurities in the air in contact there-with and to eliminate the resulting water-dissolved impurities by supplying the same, dissolved in water, as microbiologically decomposable substrate to the microorganisms colonizing or growing on the packing material. The resulting purified air, after passing through the water-wetted biologically active packing material and substantially free of contaminants is suitably disposed of and the water, also after having passed through the packing material and now having a reduced contaminant content or substantially free of contaminant, is collected and all or a portion thereof recycled to dissolve additional water soluble micro-biologically decomposable or biodegradable contaminants from the air or gaseous oxygen containing effluent to be purified.
ABSTRACT OF THE DISCLOSURE
A method and apparatus are provided for purifying air or other gaseous oxygen-containing effluent having microbiologically decomposable or biodegradable con-taminants therein. The above is accomplished by providing an array or permeable mass of packing material with colonies of microorganisms growing thereon. The packing material and/or the air to be purified is sprayed with water to dissolve out the water soluble impurities in the air in contact there-with and to eliminate the resulting water-dissolved impurities by supplying the same, dissolved in water, as microbiologically decomposable substrate to the microorganisms colonizing or growing on the packing material. The resulting purified air, after passing through the water-wetted biologically active packing material and substantially free of contaminants is suitably disposed of and the water, also after having passed through the packing material and now having a reduced contaminant content or substantially free of contaminant, is collected and all or a portion thereof recycled to dissolve additional water soluble micro-biologically decomposable or biodegradable contaminants from the air or gaseous oxygen containing effluent to be purified.
Description
;8~0 MICROBIOLOGICAL PACKING MATERIAL FOR BIO-SCRUBBER
, BACKGROUND OF THE INVENTION
Removal of contaminants from air by water scrubbing is a known technique. In water scrubbing, water soluble impurities contained in air are absorbed by spraying water into the air or by passing the air over a large, water-wetted surfaces. The large, water-wetted surface absorbs the water soluble contaminants, resulting in purified air and contaminated water.
Various approaches or techniques have been employed to treat the resulting contaminated water. Since the contaminants which are absorbed by the washwater may include, for example, amines, mercaptans, and other odiferous chemicals, purification of the resulting contaminated washwater has proceeded via chemical techniques aimed at chemical degradation of washwater contaminants. Such chemical processes, however, are not always completely satisfactory to eliminate the contaminant completely. Chemicals used in such tech-niques are also costly, and thus add even more expenseto the process to remove the undesirable contaminants from the waste water.
Biological purification of contaminated washwater is known and is an alternative. For example, German Offenlegunsgschrift 2,547,675 discloses a process whereby washwater is processed in an aerated vessel which has been equipped wi~h a biologically active 3~ sludge. The washwater is passed into the aerated vessel containing the sludge, and the biologically active bacteria contained therein then decompose the contaminants introduced therein with the washwater.
The use o~ biologicallv active sludge for purification r -~
~-~..d processes, however, brings with it difficulties in installation and maintenance which render it less useful in large scale industrial practice. Expensive and extensive equipment is usually necessary for the conventional installation of purification systems using biologically active sludge. Additionally, when separation of the sludge and purified washwater is desired, yet more equipment is necessary to effect such separation. While it is not always necessary to effect such separation in the sludge vessel, eventually such separation is required, and, as such, the apparatus for use in an activated sludge purification system must be outfitted so as to prevent damage to the micro-organisms contained in the sludge. Another problem that presents itself is the requirement of a constant supply of oxygen to the microorganisms in the bio-logically active sludge. Equipment is required to pxovide oxygen along the entire purification system.
When oxygen is not present in sufficient quantities, it has been found that anaerobic processes beyin to operate. Such anaerobic processes often produce, as by-products, odiferous compounds, thus acting to defeat the entire purpose of the purification system.
12~
SUMMARY OF THE INVENTION
Microorganisms capable of performing biological decom-position of biodegradable contaminants ox materials such as may be present in waste air, are disposed and maintained on a bed or permeable mass of packing material. The individual "packing" is desirably of a shape to provide maximum surface area per volume of packing material. Washwater which may contain the contaminants to be removed is then provided to the microorganisms and packing, such as washwater introduced into contact with waste air to remove water soluble contaminants therefrom. As the washed waste air and the washwater containing the dissolved contaminants pass through the bed of packing material, the impurities which are dissol~ed in the water, are decomposed by the microorganisms colonized on the surface of the water wetted packing material. The washwater, now having a reduced contaminant content, which percolates out of the packing material is collected and may be recycled in the purification process. The above operations or steps may be repeated, varying with the microorganisms used, and/or the chemical properties of the washwater used and the concentration and nature of the contaminants to be removed.
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DETAILED DESCRIPTIO~l OF THE INVENTION
.
A bed or an ar-ay of beds of packing material i5 prepared for use as a treating or purifying device for air to be 5 purified. The preparation involves providing on the extended surfaces of the packing material a coating or layer of microorganisms capable of decomposing biodegrad-able contaminants or waste materials and the like in the air to be purified. The coating or layer of these micro-organisms on the surfaces of the packing material can bebuilt up fairly quickly. For example, after 'he packing material has been seeded with the microorganisms, such as cultures thereof, and, if left.substantially unattended, save for applying spray or flow of water thereto in the presence of air, zn effective amount of the microorganisms can be built up on the packing material within about six weeks. This time required may be shortened if cultures of the micro-organisms are continuously introduced along with the spray or flow of water to the packing ma~erial. By follow-ing this accelerated pxocedure, an effective amount ofthe coating of the microorganisms coating the pac~ing material can be built up within a matter of a few weeks, more or less.
In part~cular, this ~nvention provides a devicefor purifying waste air by biologically decomposing the contaminant bein~ absorbed in wash water, by aerobic microorganisms, comprisin~ a washin~ unit with a bed of packing material, the wash water being guided over ths bed of packing material in a wash water circulating and waste air flowing therethrough, further comprising a growth of microorganisms on the packin~ material of the bed and a washing unit pool below the bed of packin~
material, characterized in that an array of washing unit stages are disposed one behind the other for the waste air to flow consecutively therethrough, in that each washing unit sta~e has a separate wash water circulation each with different chemical properties of wash water, and in that the packin~ material units of the beds of the washing unit sta~es have filamentous loops lying on a torus surface and being interconnected at least at one point.
- 4a ~ lZ16810 With the packing material now coated with the microorganisms, and the packing material positioned or provided within a housing provided with an air inlet and air outlet and packing material disposed within the housing so that any waste or contaminanted air introduced therein passes through the microorganism-coated packing material, upon passage of the contaminated air containing the contaminants through the packing material, the microorganisms thereon serve to effect microbiological breakdown or desradation lo of the contaminants in the air. To promote, in effect, the microbiological breakdown of the contaminants in the ~ 5_ ~ 8~0 air, water is sprayed onto air as it enters the housing and before it comes into contact with the microbiological packing material. Water is also desirably percolated down through the packing material with the result that the microbiological packing material is water wetted and maintained water wet by the water spray and the supplemental water added and percolating downwardly through the packing material. The water spray which comes into contact with the contaminated air serves to remove or dissolve or wash out the water-soluble contaminants therefrom. The spray or wash water carries the dissolved contaminants into contact with the microbiological packing material. Excess water is collected at the bottom of the housing along with the purified water which leaves the microbiological packing material and is collected at the bottom of the housing. This water collected at the bottom of the housing may be recirculated or discharged as desired.
Desirably, before the treated purified air leaves the housing, it passes through a demister or screen to remove any droplets of water therefrom. The thus-removed water would be collected in the bottom of the housing and also further recycled or recovered. The treated air, after leaving the demister, leaves the housing via an outlet in the side opposite the inlet as substantia!ly contaminant-free air. If desired, an array of microbiological packingmaterial may be employed wherein the air moves stagewise through one mass of microbiological packing material through another in substantially countercurrent contact with wash water which is initially supplied in the purified air exit end of the array and recovered at the other end of the array where the contaminated air enters.
Since the wash water leaves the treatment process described hereinabove substantially contaminant-free or having a markedly reduced contaminant content, the wash water recovered from the process can either be recycled for use -6~ 6~
in the process or discharged to waste without any further treatment because of its then relatively low biological oxygen demand ~BOD).
In carrying out the practices of this invention, various modifications are possible. For example, when the contaminants in the waste aîr to be treated are varied, a number or plurality of microorganism species may be employed, as is common in activated sludge treating plants. Further, the spray water employed may be varied by the addition of an acid or base thereto, pH control, to take advantage of optimum growth of the microorganisms making up the microbiological packing material. This modification in accordance with the practices of this invention is particularly applicable when an array of microbiological packing material is employed. In the operations in accordance with this invention, it is necessary not only that the microbiological packing material be maintained water wet so as to maintain the life and activity of the microorganisms coating the packing material but also air or oxygen-containing gas must be maintained in contact with the microbiological packing material to avoid anaerobic conditions with respect to the growth and/or utilization of the micro-organisms, since anaerobic conditions, if present duringthe overall treating process, cause the production of noxious odors and materials and defeat the purpose of the purification system.
The invention and practices thereof become more apparent with reference to the accompanying drawings wherein:
Fig. 1 schematically illustrates a contaminated waste air treating apparatus and process in accordance with this invention;
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Fig. 2 illustrates packing material useful in accordance with the practices of this invention;
Fig. 3 illustrates a variant of Fig. 1 of the appaxatus and process in accordance with this invention wherein the waste air flows countercurrently with respect to the wash water introduced into contact with the microbiological packing material; and wherein Fig. 4 illustrates a multi-stage waste air treating process in accordance with this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to Fig. 1 of the drawings showing a single step waste air treating process, contaminated waste air to be purified supplied from a source 101 enters housing 100 through an opening therein. Upon entering housing 100, the waste air is sprayed with wash water via spray head 104. Spray head or sprinkler 104 provides a fine water spray which serves to intimately contact the waste air entering housing 100 to dissolve the water-soluble contaminants therein. The resulting sprayed waste air and the finely dispersed water spray then come into contact with microbiological packins 102. As the waste air moves through microbiological packing 102, it additionally comes into contact with supplemental wash water which is sprayed onto the top of microbiological packing 102 through auxilliary spray head 104. The was~
water thus-supplied to microbiological packing 102 maintains the microorganisms on the surface of the packing material therein water wet and the wash water percolates downwardly through the microbiological material and collects as a pool 105 at the bottom of housing 100.
As the waste air moves through microbiological packing material 102, the water dissolved contaminants come into -8- ~Z~ O
ccntact with the microorganisms making up the microbio~
logical packing material and the microorganisms effectively biodegrade the dissolved contaminants. The resulting substantially purified air transversely exits the microbiological packing material through demister or screen llO for the removal of any entrained water droplets and the thus-treated air, now substantially free of con-taminants, exits the opposite side of housing 100 as substantially purified air as indicated by reference numeral lll.
In the operation of the device in accordance with ~ig. 1, wash ~ater is recycled from pool lOS at the bottom of housing 100 via line 107, pump 108 and line 103 to provide the wash water supplied to the microbiological packing material 102 via spray heads 104. If desired, wash water may be discharged from pool 105 at the bottom of housing 100 via lines 106 and 109. Also, if desired, supplemental fresh wash water may be added as required to line 103 via line 103a.
Fig. 2 illustrates in detail a preferred shape of the packing material employed in the microbiological material in accordance with the practices of this invention. As `I 25 illustrated in Fig. 2, the packing consisting of sinuous coils 112, arrang~d in the form of a torus. Coils 112 are connected to each other at their interior circumference and helà and maintained by ring 113 at their exterior pe-ipherv or circumference. The packing material illustrated in Fig. 2 provides for very effective contact between the water and air and the microorganisms coating or layering the packing material, all of which are incorporated within the microbiological packing material described in connection with Fig. 1.
~3 9 ~ 8~(3 Referring now to Fig. 3 of the drawings, there is illustrated therein an alternative or modification of the practices of this invention described hereinabove with respect to Fig. 1. In Fig. 3 contaminated air from a suitable source 115 is supplied khrough an inlet in the lower portion of housing 114 and enters the bottom thereof. The waste air then travels upwardly through housing 114 through the permeable mass 116 o~ microbiolo-gical pac~ing material wherein it is brought into contact with the microorganisms coating or layering the microbio-logical packing material 116. Microbiological packingmaterial 116 is maintained water wet or water wetted by wash water supplied to the top portion of microbiological packing material 116 via spray heads 118 supplied via line 117. As contaminated air moves upwardly through the permeable mass o~ microbiological packing material 116 the contaminants in the contaminated air become dissolved in the water wetting the microbiological packing material and the thus-dissolved contaminants are effectively microbiologically decomposed or biodegraded by the micro-organisms making up microbiological packing material 116.Purified air 124 exists the top of housing 114 after having passed through screen demister 119 to remove any entrained water droplets. As in the embodiment of the invention illustrated in Fig. 1, the wash water now substantially free of contaminants dissolved therein, collects as pool 120 in the bottom of housing 114. If desired, the substantially purified wash water can be recycled via line 121, pump 122 and line 117 to spray heads 118 to be brought into contact with additional contaminated air 115 entering via an inlet at the bottom of housing 114 as illustrated. If desired, substantially purified wash water or wash water having a reduced contaminant content, can be withdrawn from line 117 via -1O~
line 123 and additional fresh wash water can be supplied to line 117 via line 117a. The operation of the apparatus and process illustrated in Fig. 3 differs from that of Fig. 1 in that in Fig. 3 the contaminated air moves into S direct count~rcurrent contact with the wash water supplied to the opposite end or top of microbiological packing material 112, the cor~taminated waste air entering at the bottom of microbiological packing material 116.
In contrast, in Fig. 1 the contaminated waste air flows transversely through microbiological packing material 102 in substantially transverse flow relationship with the wash water which percolates or flows downwardly through microbiological packing material 102. Desirably, in the disposition of the microbiological packing material 116 provided within housing 114 the packing material as illustrated in Fig. 2 is arranged substantially parallel to the flow of the air to be treated through microbiolog-ical packing material 116.
Referring now to Fig. 4 of the drawings, there is illustrated therein an array of microbial scrubbers in accordance with the practices of this invention. In the operation of the device or array illustrated in Fig. 4, contaminated waste air 201 enters, as illustrated, one end of housing 200 and proceeds therethrough transversely across the length of housing 200. In Fig. 4 there are employed multiple biological scrubbers 211. The contam-inated waste air passes transversely through scrubbers 211 and exits housing 200 at the opposite end as substan-tially purified air or air having a substantially reducedcontaminant content. The air undergoing treatment within housing 201 passes, in effect, countercurrently with respect to the wash water which is supplied via line 206 to form a pool in the bottom of housing 200. Dams 200a are provided in the bottom of housing 200 to provide separate pools 203, 204, 205 of wash water at the bottom of housing 200.
Accordingly, in the operation of the apparatus illus-trated in Fig. 4I wash water is picked up from pool 203 in the bottom of housing 200 via line 207 provided with pump 207a and supplied to spray heads 208 which serve to supply the wash water to microbiological packing material 211 through suitable openings in the top of housing 200.
The wash water supplied to microbiological packing material 211 via spray heads 208 serve to maintain the microorgan-isms and the microbiological packing material water wet and to dissolve any contaminants in the air moving trans~
versely through microbiologically packing material 211.
The wash water percolates or flows downwardly through microbiological packing material 211 and is collected in pool 203 in the bottom of housing 200. The wash water may be recirculated at least in part from pool 203 via pump 207a and line 207 to spray heads 208 to contact and percolate downwardly through microbiological packing material 211 to contact additional waste flowing there-through. A portion of the wash water from pool 203 is transferred via pump 207a and lines 207 and 209 to wash water pool 204 adjacent pool 203 in the downstream direction of the flow of wash water through housing 200 which enters via line 206 and leaves via line 210.
The wash water from pool 204 moves via pump 212a and line 212 to spray heads 208 to the top of the adjacent array of microbiological pac~ing material 211 for flow downwardly therethrough to wet the microorganisms in the microbiolog-ical packing material 201 to maintain such microorganisms active and to dissolve the contaminants in the air transversely entering microbiological packing material -12~ i8~C~
211 for flow therethrough and for the microbiological removal of the contaminants therefrom, all as described hereinabove.
The wash water from pool 204 is then moved via pump 212a and lines 212 and 215 to adjacent wash wate~ pool 205.
From pool 205 the wash water is moved via pump 214a and line 214 to spray heads 208 to the top of microbiological packing material 210 for flow downwardly therethrough to maintain the microorganisms therein water wet and active and to dissolve the water-soluble contaminants from the contaminated waste air 201 entering housing 201, as illustrated, so as to dissolve the water-soluble contam-inants therein and to bring the thus dissolved contam-inants into contact with the microorganisms to effect their microbiological breakdown on the microbiological packing material 211. Wash water is recovered from pool 205 via pump 214 and may be discharged, as required, via line 210.
In the apparatus and operation illustrated in Fig. 4, there is multiple countercurrent contact between the wash water entering one end of housing 200 via line 206 and exiting the opposite end of housing 200 via line 210 and the contaminated waste air or oxygen-containing gases which enter said opposite end of housing 210, see waste gas 201. After treatment through the array of microbio-logical packing materials 210, the resultin~ treated waste gas exits housing 200 as substantially purified air or air having a substantially reduced contaminant content 216.
As is evident from the operation of the device of Fig.
and Fig. 4 of the drawings, there is a cross or transverse flow contact between the wash water and the contaminated -13- ~ 8~
waste air undergoing treatment. The gases moving perpen-dicularly with respect to descending flow of wash water on the microbiological packing material. In the device of Fig. 3, there is a conventional countercurrent contact between the waste air being treated and the flow of wash water in contact therewith, ~he waste air moving in direct countercurxent contact with the wash water percolating or flowing downwardly within the microbiological packing material against the upward flow of the waste air there-throughO In the operation of the devices in accordancewith this invention employing microbiological packing material comprising a coating of layer or active micro-organisms on surface packing material, the nitrogen or sulfur-containing contaminants for the most part are microbiologically degraded into water-soluble derivatives, such as nitrates and sulfates, which are eventually discharged with the wash water. If desired, these values, such as nitrates and sulfates, could be recovered from the discharged waste waters.
Further, as indicated hereinabove, the composition of the wash water can be adjusted to promote not only the absorp-tion or dissolution of the water-soluble contaminants present in the waste air undergoing treatment but also to chemically react therewith to provide a more readily biodegradable product which would then be more readily removed or microbiologically decomposed or degraded by the microorganisms coating the microbiological packing material. For example, acids could be converted into salts thereof by providing a base, such as sodium hydrox-ide, in the wash water or basic acting materials, such as amines, could be reacted with acids provided in the wash water to convert the same to a more readily biodegradable form or salt. The concentrations of any additives present in the wash water should be such as to not interfere with -14- ~ Z~ C~
the activity or growth or effectiveness of the microorgan~
isms making up the microbiological packing material. In the practices of this invention the dissolved contaminants taken from the waste air undergoing treatment would serve as a substrate or, in effect, fuel or sustenance ~or the microorganisms making up the microbiological packing material. To maintain an active growth of the microorgan-isms on the microbiological packing material,either initially in the build up of the microbiological packing material and during the active use of the microorganisms ln the microbiological packing material for the removal of contaminants, it is desirable to supply nutrients, if not otherwise supplied by the contaminants, to the microorganisms making up the microbiological packing material. Suitable such nutrients would include conven-tional carbon sources, such as sugars, starch hydrolysates, nitrogen sources, such as nitrates, phosphates, such as water-soluble phosphates, amino acids, such as might be obtainable from yeast hydrolysates, and essential minerals as may be required, such as magnesium sources, cobalt sources, iron sources. All such materials would be added in minor dilu~e concentrations desirable to maintain the activity of the microorganisms employed.
A useful source of the microorganisms in the make-up and utilization of the microbiological packing material would be microorganisms present in sewage disposal plants employing activated sludge. Such microorganisms could very usefully be employed and adap~ed in the practices of this invention. For example, suitably diluted activated sludge could be employed to make up the microorganism content of the microbiological packing material in whole or in part. Other microorganisms particularly adapted ~or the handling of special contaminants which may be -15- ~ Z~
present in the contaminated air to be treated might also be employed. The identification and techniques of employ-ing such microorganisms, especially those employed in activated sludge waste disposal operations, are well known.
Additionally, it is desirable to maintain the microbio-logical packing material operation at a temperature at which the microorganisms efficiently and effectively serve to degrade the water-soluble contaminants in contact therewith. Ambient temperatures, such as temperatures in the range from about 5C., more or less, to about 50-60C. may be employed, depending upon~the microorgan-isms making up the microbiological packing material.
Normally, a temperature range of about 15C. to about 30C. is employed in the operation of the devices and practices of this invention.
The packing material upon which the microorganisms are deposited to form a coating or layer thereon is desirably inertf not only with respect to the activity of the microorganisms but also with respect to the contaminants to be removed. Ceramic shapes having a high surface area per unit volume or weight are useful, as well as metal shapes, such as stainless steel forms, which provide a very high surface area while at the same time permitting low pressure drop or high permeability with respect to the flow of gases and/or wash water therethrough. As indicated, it is important in the practices of this invention to operàte the devices and pro~esses to main-- tain an oxygen-containing gaseous atmosphere in contact with the microbiological packing material to avoid anaerobic growth of the microorganisms.
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In the practices of this invention, as stated hereinabove, the packing material is desirably inert with respect to the contaminated waste air flowing in contact therewith as well as with respect to the wash water appli~d to the packing material. The packing material accordingly can be made of any substantially inert metal material, such as stainless steel, a ceramic material, such as a preformed aluminum shape, or plastic material, e.g.
preformed polyethylene, polypropylene, nylon and the like.
When multiple beds of packing material are employed for consecutive contact of the waste air undergoing treatment, the beds of packing material may be separately contained, each bed of packing material being contained within its own housing. Desirably, however, when multiple beds or an array of beds of packing material are employed multiple beds or an array of multiple beds are contained within a single housing either disposed horizontally, as illustrated in Fig. 4, or vertically, as may be convenient or desired.
The purification treatment in accordance with this invention wherein waste air containing biodegradable contaminants is brought into contact with one or more beds of packing material, the packing material having a growth of microorganisms on the surfaces thereof for microbiological decomposition of the biodegradable contaminants brought into contact therewith, may be carried out at ambient pressure or even, if desired, at a sub-atmospheric or supra-atmospheric pressure. Desirably, the waste gases undergoing treatment are at substantially a~bient pressure or a pressure sufficient to move the waste air undergoing treatment through the beds of packing material. Supra-atmospheric pressure, such as pressures up to about 10-25 pounds per square inch above atmospheric pressure, might conveniently be employed since such supra-atmospheric pressure would tend to speed up the microbiological decomposition of the contaminants exposed to the microorganisms on the packing material. Similarly, a moderate increase in temperature, such as a temperature in the range 20-50C. maintained during the contacting operation with or ~ithout an increase in pressure would also tend to speed up the microobiological decomposition treatment operation in accordance with the practices of this invention.
The packing material provided with an active growth of microorganisms on the surfaces thereof, the microorgan-isms being employed for the microbial or microbiological decomposition of waste air contaminants supplied thereto can be envisaged or likened to a field of microorganisms, e.g. a microbiological lawn, which, when maintained active and water wetted, absorbs and makes available for the growth of the microorganisms, or the microbiological lawn, the biodegradable contaminants brought into contact therewith.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many modifications, alterations and substitutions are possible in the practice of this invention without departing from the spirit or scope thereof.
, BACKGROUND OF THE INVENTION
Removal of contaminants from air by water scrubbing is a known technique. In water scrubbing, water soluble impurities contained in air are absorbed by spraying water into the air or by passing the air over a large, water-wetted surfaces. The large, water-wetted surface absorbs the water soluble contaminants, resulting in purified air and contaminated water.
Various approaches or techniques have been employed to treat the resulting contaminated water. Since the contaminants which are absorbed by the washwater may include, for example, amines, mercaptans, and other odiferous chemicals, purification of the resulting contaminated washwater has proceeded via chemical techniques aimed at chemical degradation of washwater contaminants. Such chemical processes, however, are not always completely satisfactory to eliminate the contaminant completely. Chemicals used in such tech-niques are also costly, and thus add even more expenseto the process to remove the undesirable contaminants from the waste water.
Biological purification of contaminated washwater is known and is an alternative. For example, German Offenlegunsgschrift 2,547,675 discloses a process whereby washwater is processed in an aerated vessel which has been equipped wi~h a biologically active 3~ sludge. The washwater is passed into the aerated vessel containing the sludge, and the biologically active bacteria contained therein then decompose the contaminants introduced therein with the washwater.
The use o~ biologicallv active sludge for purification r -~
~-~..d processes, however, brings with it difficulties in installation and maintenance which render it less useful in large scale industrial practice. Expensive and extensive equipment is usually necessary for the conventional installation of purification systems using biologically active sludge. Additionally, when separation of the sludge and purified washwater is desired, yet more equipment is necessary to effect such separation. While it is not always necessary to effect such separation in the sludge vessel, eventually such separation is required, and, as such, the apparatus for use in an activated sludge purification system must be outfitted so as to prevent damage to the micro-organisms contained in the sludge. Another problem that presents itself is the requirement of a constant supply of oxygen to the microorganisms in the bio-logically active sludge. Equipment is required to pxovide oxygen along the entire purification system.
When oxygen is not present in sufficient quantities, it has been found that anaerobic processes beyin to operate. Such anaerobic processes often produce, as by-products, odiferous compounds, thus acting to defeat the entire purpose of the purification system.
12~
SUMMARY OF THE INVENTION
Microorganisms capable of performing biological decom-position of biodegradable contaminants ox materials such as may be present in waste air, are disposed and maintained on a bed or permeable mass of packing material. The individual "packing" is desirably of a shape to provide maximum surface area per volume of packing material. Washwater which may contain the contaminants to be removed is then provided to the microorganisms and packing, such as washwater introduced into contact with waste air to remove water soluble contaminants therefrom. As the washed waste air and the washwater containing the dissolved contaminants pass through the bed of packing material, the impurities which are dissol~ed in the water, are decomposed by the microorganisms colonized on the surface of the water wetted packing material. The washwater, now having a reduced contaminant content, which percolates out of the packing material is collected and may be recycled in the purification process. The above operations or steps may be repeated, varying with the microorganisms used, and/or the chemical properties of the washwater used and the concentration and nature of the contaminants to be removed.
~Z~61~
DETAILED DESCRIPTIO~l OF THE INVENTION
.
A bed or an ar-ay of beds of packing material i5 prepared for use as a treating or purifying device for air to be 5 purified. The preparation involves providing on the extended surfaces of the packing material a coating or layer of microorganisms capable of decomposing biodegrad-able contaminants or waste materials and the like in the air to be purified. The coating or layer of these micro-organisms on the surfaces of the packing material can bebuilt up fairly quickly. For example, after 'he packing material has been seeded with the microorganisms, such as cultures thereof, and, if left.substantially unattended, save for applying spray or flow of water thereto in the presence of air, zn effective amount of the microorganisms can be built up on the packing material within about six weeks. This time required may be shortened if cultures of the micro-organisms are continuously introduced along with the spray or flow of water to the packing ma~erial. By follow-ing this accelerated pxocedure, an effective amount ofthe coating of the microorganisms coating the pac~ing material can be built up within a matter of a few weeks, more or less.
In part~cular, this ~nvention provides a devicefor purifying waste air by biologically decomposing the contaminant bein~ absorbed in wash water, by aerobic microorganisms, comprisin~ a washin~ unit with a bed of packing material, the wash water being guided over ths bed of packing material in a wash water circulating and waste air flowing therethrough, further comprising a growth of microorganisms on the packin~ material of the bed and a washing unit pool below the bed of packin~
material, characterized in that an array of washing unit stages are disposed one behind the other for the waste air to flow consecutively therethrough, in that each washing unit sta~e has a separate wash water circulation each with different chemical properties of wash water, and in that the packin~ material units of the beds of the washing unit sta~es have filamentous loops lying on a torus surface and being interconnected at least at one point.
- 4a ~ lZ16810 With the packing material now coated with the microorganisms, and the packing material positioned or provided within a housing provided with an air inlet and air outlet and packing material disposed within the housing so that any waste or contaminanted air introduced therein passes through the microorganism-coated packing material, upon passage of the contaminated air containing the contaminants through the packing material, the microorganisms thereon serve to effect microbiological breakdown or desradation lo of the contaminants in the air. To promote, in effect, the microbiological breakdown of the contaminants in the ~ 5_ ~ 8~0 air, water is sprayed onto air as it enters the housing and before it comes into contact with the microbiological packing material. Water is also desirably percolated down through the packing material with the result that the microbiological packing material is water wetted and maintained water wet by the water spray and the supplemental water added and percolating downwardly through the packing material. The water spray which comes into contact with the contaminated air serves to remove or dissolve or wash out the water-soluble contaminants therefrom. The spray or wash water carries the dissolved contaminants into contact with the microbiological packing material. Excess water is collected at the bottom of the housing along with the purified water which leaves the microbiological packing material and is collected at the bottom of the housing. This water collected at the bottom of the housing may be recirculated or discharged as desired.
Desirably, before the treated purified air leaves the housing, it passes through a demister or screen to remove any droplets of water therefrom. The thus-removed water would be collected in the bottom of the housing and also further recycled or recovered. The treated air, after leaving the demister, leaves the housing via an outlet in the side opposite the inlet as substantia!ly contaminant-free air. If desired, an array of microbiological packingmaterial may be employed wherein the air moves stagewise through one mass of microbiological packing material through another in substantially countercurrent contact with wash water which is initially supplied in the purified air exit end of the array and recovered at the other end of the array where the contaminated air enters.
Since the wash water leaves the treatment process described hereinabove substantially contaminant-free or having a markedly reduced contaminant content, the wash water recovered from the process can either be recycled for use -6~ 6~
in the process or discharged to waste without any further treatment because of its then relatively low biological oxygen demand ~BOD).
In carrying out the practices of this invention, various modifications are possible. For example, when the contaminants in the waste aîr to be treated are varied, a number or plurality of microorganism species may be employed, as is common in activated sludge treating plants. Further, the spray water employed may be varied by the addition of an acid or base thereto, pH control, to take advantage of optimum growth of the microorganisms making up the microbiological packing material. This modification in accordance with the practices of this invention is particularly applicable when an array of microbiological packing material is employed. In the operations in accordance with this invention, it is necessary not only that the microbiological packing material be maintained water wet so as to maintain the life and activity of the microorganisms coating the packing material but also air or oxygen-containing gas must be maintained in contact with the microbiological packing material to avoid anaerobic conditions with respect to the growth and/or utilization of the micro-organisms, since anaerobic conditions, if present duringthe overall treating process, cause the production of noxious odors and materials and defeat the purpose of the purification system.
The invention and practices thereof become more apparent with reference to the accompanying drawings wherein:
Fig. 1 schematically illustrates a contaminated waste air treating apparatus and process in accordance with this invention;
-7~ 6~1~
Fig. 2 illustrates packing material useful in accordance with the practices of this invention;
Fig. 3 illustrates a variant of Fig. 1 of the appaxatus and process in accordance with this invention wherein the waste air flows countercurrently with respect to the wash water introduced into contact with the microbiological packing material; and wherein Fig. 4 illustrates a multi-stage waste air treating process in accordance with this invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to Fig. 1 of the drawings showing a single step waste air treating process, contaminated waste air to be purified supplied from a source 101 enters housing 100 through an opening therein. Upon entering housing 100, the waste air is sprayed with wash water via spray head 104. Spray head or sprinkler 104 provides a fine water spray which serves to intimately contact the waste air entering housing 100 to dissolve the water-soluble contaminants therein. The resulting sprayed waste air and the finely dispersed water spray then come into contact with microbiological packins 102. As the waste air moves through microbiological packing 102, it additionally comes into contact with supplemental wash water which is sprayed onto the top of microbiological packing 102 through auxilliary spray head 104. The was~
water thus-supplied to microbiological packing 102 maintains the microorganisms on the surface of the packing material therein water wet and the wash water percolates downwardly through the microbiological material and collects as a pool 105 at the bottom of housing 100.
As the waste air moves through microbiological packing material 102, the water dissolved contaminants come into -8- ~Z~ O
ccntact with the microorganisms making up the microbio~
logical packing material and the microorganisms effectively biodegrade the dissolved contaminants. The resulting substantially purified air transversely exits the microbiological packing material through demister or screen llO for the removal of any entrained water droplets and the thus-treated air, now substantially free of con-taminants, exits the opposite side of housing 100 as substantially purified air as indicated by reference numeral lll.
In the operation of the device in accordance with ~ig. 1, wash ~ater is recycled from pool lOS at the bottom of housing 100 via line 107, pump 108 and line 103 to provide the wash water supplied to the microbiological packing material 102 via spray heads 104. If desired, wash water may be discharged from pool 105 at the bottom of housing 100 via lines 106 and 109. Also, if desired, supplemental fresh wash water may be added as required to line 103 via line 103a.
Fig. 2 illustrates in detail a preferred shape of the packing material employed in the microbiological material in accordance with the practices of this invention. As `I 25 illustrated in Fig. 2, the packing consisting of sinuous coils 112, arrang~d in the form of a torus. Coils 112 are connected to each other at their interior circumference and helà and maintained by ring 113 at their exterior pe-ipherv or circumference. The packing material illustrated in Fig. 2 provides for very effective contact between the water and air and the microorganisms coating or layering the packing material, all of which are incorporated within the microbiological packing material described in connection with Fig. 1.
~3 9 ~ 8~(3 Referring now to Fig. 3 of the drawings, there is illustrated therein an alternative or modification of the practices of this invention described hereinabove with respect to Fig. 1. In Fig. 3 contaminated air from a suitable source 115 is supplied khrough an inlet in the lower portion of housing 114 and enters the bottom thereof. The waste air then travels upwardly through housing 114 through the permeable mass 116 o~ microbiolo-gical pac~ing material wherein it is brought into contact with the microorganisms coating or layering the microbio-logical packing material 116. Microbiological packingmaterial 116 is maintained water wet or water wetted by wash water supplied to the top portion of microbiological packing material 116 via spray heads 118 supplied via line 117. As contaminated air moves upwardly through the permeable mass o~ microbiological packing material 116 the contaminants in the contaminated air become dissolved in the water wetting the microbiological packing material and the thus-dissolved contaminants are effectively microbiologically decomposed or biodegraded by the micro-organisms making up microbiological packing material 116.Purified air 124 exists the top of housing 114 after having passed through screen demister 119 to remove any entrained water droplets. As in the embodiment of the invention illustrated in Fig. 1, the wash water now substantially free of contaminants dissolved therein, collects as pool 120 in the bottom of housing 114. If desired, the substantially purified wash water can be recycled via line 121, pump 122 and line 117 to spray heads 118 to be brought into contact with additional contaminated air 115 entering via an inlet at the bottom of housing 114 as illustrated. If desired, substantially purified wash water or wash water having a reduced contaminant content, can be withdrawn from line 117 via -1O~
line 123 and additional fresh wash water can be supplied to line 117 via line 117a. The operation of the apparatus and process illustrated in Fig. 3 differs from that of Fig. 1 in that in Fig. 3 the contaminated air moves into S direct count~rcurrent contact with the wash water supplied to the opposite end or top of microbiological packing material 112, the cor~taminated waste air entering at the bottom of microbiological packing material 116.
In contrast, in Fig. 1 the contaminated waste air flows transversely through microbiological packing material 102 in substantially transverse flow relationship with the wash water which percolates or flows downwardly through microbiological packing material 102. Desirably, in the disposition of the microbiological packing material 116 provided within housing 114 the packing material as illustrated in Fig. 2 is arranged substantially parallel to the flow of the air to be treated through microbiolog-ical packing material 116.
Referring now to Fig. 4 of the drawings, there is illustrated therein an array of microbial scrubbers in accordance with the practices of this invention. In the operation of the device or array illustrated in Fig. 4, contaminated waste air 201 enters, as illustrated, one end of housing 200 and proceeds therethrough transversely across the length of housing 200. In Fig. 4 there are employed multiple biological scrubbers 211. The contam-inated waste air passes transversely through scrubbers 211 and exits housing 200 at the opposite end as substan-tially purified air or air having a substantially reducedcontaminant content. The air undergoing treatment within housing 201 passes, in effect, countercurrently with respect to the wash water which is supplied via line 206 to form a pool in the bottom of housing 200. Dams 200a are provided in the bottom of housing 200 to provide separate pools 203, 204, 205 of wash water at the bottom of housing 200.
Accordingly, in the operation of the apparatus illus-trated in Fig. 4I wash water is picked up from pool 203 in the bottom of housing 200 via line 207 provided with pump 207a and supplied to spray heads 208 which serve to supply the wash water to microbiological packing material 211 through suitable openings in the top of housing 200.
The wash water supplied to microbiological packing material 211 via spray heads 208 serve to maintain the microorgan-isms and the microbiological packing material water wet and to dissolve any contaminants in the air moving trans~
versely through microbiologically packing material 211.
The wash water percolates or flows downwardly through microbiological packing material 211 and is collected in pool 203 in the bottom of housing 200. The wash water may be recirculated at least in part from pool 203 via pump 207a and line 207 to spray heads 208 to contact and percolate downwardly through microbiological packing material 211 to contact additional waste flowing there-through. A portion of the wash water from pool 203 is transferred via pump 207a and lines 207 and 209 to wash water pool 204 adjacent pool 203 in the downstream direction of the flow of wash water through housing 200 which enters via line 206 and leaves via line 210.
The wash water from pool 204 moves via pump 212a and line 212 to spray heads 208 to the top of the adjacent array of microbiological pac~ing material 211 for flow downwardly therethrough to wet the microorganisms in the microbiolog-ical packing material 201 to maintain such microorganisms active and to dissolve the contaminants in the air transversely entering microbiological packing material -12~ i8~C~
211 for flow therethrough and for the microbiological removal of the contaminants therefrom, all as described hereinabove.
The wash water from pool 204 is then moved via pump 212a and lines 212 and 215 to adjacent wash wate~ pool 205.
From pool 205 the wash water is moved via pump 214a and line 214 to spray heads 208 to the top of microbiological packing material 210 for flow downwardly therethrough to maintain the microorganisms therein water wet and active and to dissolve the water-soluble contaminants from the contaminated waste air 201 entering housing 201, as illustrated, so as to dissolve the water-soluble contam-inants therein and to bring the thus dissolved contam-inants into contact with the microorganisms to effect their microbiological breakdown on the microbiological packing material 211. Wash water is recovered from pool 205 via pump 214 and may be discharged, as required, via line 210.
In the apparatus and operation illustrated in Fig. 4, there is multiple countercurrent contact between the wash water entering one end of housing 200 via line 206 and exiting the opposite end of housing 200 via line 210 and the contaminated waste air or oxygen-containing gases which enter said opposite end of housing 210, see waste gas 201. After treatment through the array of microbio-logical packing materials 210, the resultin~ treated waste gas exits housing 200 as substantially purified air or air having a substantially reduced contaminant content 216.
As is evident from the operation of the device of Fig.
and Fig. 4 of the drawings, there is a cross or transverse flow contact between the wash water and the contaminated -13- ~ 8~
waste air undergoing treatment. The gases moving perpen-dicularly with respect to descending flow of wash water on the microbiological packing material. In the device of Fig. 3, there is a conventional countercurrent contact between the waste air being treated and the flow of wash water in contact therewith, ~he waste air moving in direct countercurxent contact with the wash water percolating or flowing downwardly within the microbiological packing material against the upward flow of the waste air there-throughO In the operation of the devices in accordancewith this invention employing microbiological packing material comprising a coating of layer or active micro-organisms on surface packing material, the nitrogen or sulfur-containing contaminants for the most part are microbiologically degraded into water-soluble derivatives, such as nitrates and sulfates, which are eventually discharged with the wash water. If desired, these values, such as nitrates and sulfates, could be recovered from the discharged waste waters.
Further, as indicated hereinabove, the composition of the wash water can be adjusted to promote not only the absorp-tion or dissolution of the water-soluble contaminants present in the waste air undergoing treatment but also to chemically react therewith to provide a more readily biodegradable product which would then be more readily removed or microbiologically decomposed or degraded by the microorganisms coating the microbiological packing material. For example, acids could be converted into salts thereof by providing a base, such as sodium hydrox-ide, in the wash water or basic acting materials, such as amines, could be reacted with acids provided in the wash water to convert the same to a more readily biodegradable form or salt. The concentrations of any additives present in the wash water should be such as to not interfere with -14- ~ Z~ C~
the activity or growth or effectiveness of the microorgan~
isms making up the microbiological packing material. In the practices of this invention the dissolved contaminants taken from the waste air undergoing treatment would serve as a substrate or, in effect, fuel or sustenance ~or the microorganisms making up the microbiological packing material. To maintain an active growth of the microorgan-isms on the microbiological packing material,either initially in the build up of the microbiological packing material and during the active use of the microorganisms ln the microbiological packing material for the removal of contaminants, it is desirable to supply nutrients, if not otherwise supplied by the contaminants, to the microorganisms making up the microbiological packing material. Suitable such nutrients would include conven-tional carbon sources, such as sugars, starch hydrolysates, nitrogen sources, such as nitrates, phosphates, such as water-soluble phosphates, amino acids, such as might be obtainable from yeast hydrolysates, and essential minerals as may be required, such as magnesium sources, cobalt sources, iron sources. All such materials would be added in minor dilu~e concentrations desirable to maintain the activity of the microorganisms employed.
A useful source of the microorganisms in the make-up and utilization of the microbiological packing material would be microorganisms present in sewage disposal plants employing activated sludge. Such microorganisms could very usefully be employed and adap~ed in the practices of this invention. For example, suitably diluted activated sludge could be employed to make up the microorganism content of the microbiological packing material in whole or in part. Other microorganisms particularly adapted ~or the handling of special contaminants which may be -15- ~ Z~
present in the contaminated air to be treated might also be employed. The identification and techniques of employ-ing such microorganisms, especially those employed in activated sludge waste disposal operations, are well known.
Additionally, it is desirable to maintain the microbio-logical packing material operation at a temperature at which the microorganisms efficiently and effectively serve to degrade the water-soluble contaminants in contact therewith. Ambient temperatures, such as temperatures in the range from about 5C., more or less, to about 50-60C. may be employed, depending upon~the microorgan-isms making up the microbiological packing material.
Normally, a temperature range of about 15C. to about 30C. is employed in the operation of the devices and practices of this invention.
The packing material upon which the microorganisms are deposited to form a coating or layer thereon is desirably inertf not only with respect to the activity of the microorganisms but also with respect to the contaminants to be removed. Ceramic shapes having a high surface area per unit volume or weight are useful, as well as metal shapes, such as stainless steel forms, which provide a very high surface area while at the same time permitting low pressure drop or high permeability with respect to the flow of gases and/or wash water therethrough. As indicated, it is important in the practices of this invention to operàte the devices and pro~esses to main-- tain an oxygen-containing gaseous atmosphere in contact with the microbiological packing material to avoid anaerobic growth of the microorganisms.
-16- ~Z~6~
In the practices of this invention, as stated hereinabove, the packing material is desirably inert with respect to the contaminated waste air flowing in contact therewith as well as with respect to the wash water appli~d to the packing material. The packing material accordingly can be made of any substantially inert metal material, such as stainless steel, a ceramic material, such as a preformed aluminum shape, or plastic material, e.g.
preformed polyethylene, polypropylene, nylon and the like.
When multiple beds of packing material are employed for consecutive contact of the waste air undergoing treatment, the beds of packing material may be separately contained, each bed of packing material being contained within its own housing. Desirably, however, when multiple beds or an array of beds of packing material are employed multiple beds or an array of multiple beds are contained within a single housing either disposed horizontally, as illustrated in Fig. 4, or vertically, as may be convenient or desired.
The purification treatment in accordance with this invention wherein waste air containing biodegradable contaminants is brought into contact with one or more beds of packing material, the packing material having a growth of microorganisms on the surfaces thereof for microbiological decomposition of the biodegradable contaminants brought into contact therewith, may be carried out at ambient pressure or even, if desired, at a sub-atmospheric or supra-atmospheric pressure. Desirably, the waste gases undergoing treatment are at substantially a~bient pressure or a pressure sufficient to move the waste air undergoing treatment through the beds of packing material. Supra-atmospheric pressure, such as pressures up to about 10-25 pounds per square inch above atmospheric pressure, might conveniently be employed since such supra-atmospheric pressure would tend to speed up the microbiological decomposition of the contaminants exposed to the microorganisms on the packing material. Similarly, a moderate increase in temperature, such as a temperature in the range 20-50C. maintained during the contacting operation with or ~ithout an increase in pressure would also tend to speed up the microobiological decomposition treatment operation in accordance with the practices of this invention.
The packing material provided with an active growth of microorganisms on the surfaces thereof, the microorgan-isms being employed for the microbial or microbiological decomposition of waste air contaminants supplied thereto can be envisaged or likened to a field of microorganisms, e.g. a microbiological lawn, which, when maintained active and water wetted, absorbs and makes available for the growth of the microorganisms, or the microbiological lawn, the biodegradable contaminants brought into contact therewith.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many modifications, alterations and substitutions are possible in the practice of this invention without departing from the spirit or scope thereof.
Claims (2)
IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Device for purifying waste air by biologically decomposing the contaminant being absorbed in wash water, by aerobic microorganisms, comprising a washing unit with a bed of packing material, the wash water being guided over the bed of packing material in a wash water circulating and waste air flowing therethrough, further comprising a growth of microorganisms on the packing material of the bed and a washing unit pool below the bed of packing material, characterized in that an array of washing unit stages are disposed one behind the other for the waste air to flow consecutively therethrough, in that each washing unit stage has a separate wash water circulation each with different chemical properties of wash water, and in that the packing material units of the beds of the washing unit stages have filamentous loops lying on a torus surface and being interconnected at least at one point.
2. Device according to claim 1, characterized in that in the pool of the washing unit the wash water is circulated through a bottom flushing device.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823217923 DE3217923A1 (en) | 1982-05-13 | 1982-05-13 | METHOD AND DEVICE FOR PURIFYING EXHAUST AIR |
| DEP3217923.5 | 1982-05-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1216810A true CA1216810A (en) | 1987-01-20 |
Family
ID=6163411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000427789A Expired CA1216810A (en) | 1982-05-13 | 1983-05-10 | Process and equipment for purifying waste air |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0094573B1 (en) |
| AT (1) | ATE21833T1 (en) |
| AU (1) | AU578229B2 (en) |
| CA (1) | CA1216810A (en) |
| DE (2) | DE3217923A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3345944A1 (en) * | 1983-12-20 | 1985-07-04 | Dechema Deutsche Gesellschaft F. Chem. Apparatewesen E.V., 6000 Frankfurt | METHOD FOR SEPARATING GASEOUS ORGANIC POLLUTANTS THAT MAY ALSO BE IN TRACKS FROM EXHAUST GASES BY BIOLOGICAL OXIDATION BY means of BACTERIA |
| DE3428798A1 (en) * | 1984-01-26 | 1985-08-01 | Linde Ag, 6200 Wiesbaden | Apparatus for purifying exhaust gas |
| BR8507302A (en) * | 1984-12-22 | 1987-11-03 | Schmidt Menzolit | PROCESS AND DEVICE FOR PURIFICATION OF DISCHARGE AIR POLLUTED WITH STYLENE |
| DE3542345A1 (en) * | 1985-11-29 | 1987-06-04 | Imhausen Chemie Gmbh | METHOD FOR REMOVING SULDURATE FROM EXHAUST GAS |
| DE3608170A1 (en) * | 1986-03-12 | 1987-09-17 | Gewerk Keramchemie | METHOD AND DEVICE FOR PURIFYING EXHAUST AIR EXTRACTED WITH BIODEGRADABLE POLLUTIONS |
| AT388313B (en) * | 1987-10-19 | 1989-06-12 | Waagner Biro Ag | METHOD FOR THE MICROBIOLOGICAL CONVERSION OF SULFURIZED POLLUTANTS IN EXHAUST GAS |
| DE9006261U1 (en) * | 1990-06-02 | 1991-10-17 | Schönhammer, Johann, 84152 Mengkofen | Biological exhaust air scrubber for an animal stable |
| DE4025343A1 (en) * | 1990-08-10 | 1992-02-13 | Bayer Ag | METHOD FOR BIOLOGICAL PURIFICATION OF EXHAUST AIR FLOWS |
| DE4204190C2 (en) * | 1991-02-08 | 1994-06-16 | Herbst Umwelttech Gmbh | Method and device for gas cleaning |
| DE4129101C1 (en) * | 1991-09-02 | 1993-04-08 | Peter Prof. Dr. 7500 Karlsruhe De Kunz | Appts. for biologically cleaning air - includes bio-absorber unit with carriers of spherical, hollow parts having lateral ribs which dip into wash soln. |
| DE4232992A1 (en) * | 1992-10-01 | 1994-04-07 | Kus Kottwitz Umweltschutz Syst | Process for the biological purification of exhaust air |
| DE4338480A1 (en) * | 1993-08-26 | 1995-03-02 | Norddeutsche Seekabelwerke Ag | Packing material for trickling filters for treating fluids and process for the production of the same |
| FR2711922B1 (en) * | 1993-11-02 | 1996-01-05 | Omnium Traitement Valorisa | Process for the purification and biodeodorization of a gaseous effluent and installation for the implementation of such a process. |
| JPH09313860A (en) * | 1996-05-27 | 1997-12-09 | Shigeru Saito | Wet type gas treating device for simultaneously contaminant and dust and method therefor |
| DE29621395U1 (en) * | 1996-12-10 | 1997-03-13 | Korte-Stroot, Susanne Maria, Dipl.-Ing. (FH), 48480 Spelle | A biofilter operated with plastic bodies as a filter medium or carrier material for biological exhaust air purification in animal husbandry |
| CN110755971A (en) * | 2018-07-25 | 2020-02-07 | 曲靖市首锋矿山配件有限公司 | Steel rolling production tail gas treatment system |
| CN114307622B (en) * | 2022-01-04 | 2022-10-11 | 深圳市腾浪再生资源发展有限公司 | Biological filter bed exhaust gas purification device |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1701825A (en) * | 1925-12-26 | 1929-02-12 | Koppers Co Inc | Gas-purification process |
| US2200581A (en) * | 1934-12-24 | 1940-05-14 | Pruss Max | Purification of gases by biological means |
| US3216905A (en) * | 1963-06-12 | 1965-11-09 | Grace W R & Co | Purification of gas with soil microorganisms |
| US3556734A (en) * | 1968-02-05 | 1971-01-19 | Leander J Peterson | Exhaust gas conditioning apparatus |
| US3686830A (en) * | 1970-08-03 | 1972-08-29 | Richard L Huntington | Multiple compartment cross flow absorber |
| US3752453A (en) * | 1971-02-19 | 1973-08-14 | Ceilcote Co Inc | Packing material unit |
| US3948608A (en) * | 1972-03-24 | 1976-04-06 | Weir Jr Alexander | Apparatus for treating stack gases |
| DE2237929C2 (en) * | 1972-08-02 | 1983-02-03 | Schumacher'sche Fabrik Gmbh & Co Kg, 7120 Bietigheim-Bissingen | Method for removing contaminants from an exhaust gas |
| DE2547675B2 (en) * | 1975-10-24 | 1978-06-01 | Daimler-Benz Ag, 7000 Stuttgart | Process for the wet cleaning of polluted exhaust air |
| US4039307A (en) * | 1976-02-13 | 1977-08-02 | Envirotech Corporation | Countercurrent flow horizontal spray absorber |
| DE2643211A1 (en) * | 1976-09-25 | 1978-04-06 | Gewerk Keramchemie | Exhaust air purification system - using scrubber with activated sludge in washing medium for biological digestion of impurities |
| DE2746648A1 (en) * | 1977-10-17 | 1979-04-26 | Walter Dr Albersmeyer | Liq. purificn. in contact beds - with direct introduction of oxygen for microorganism growth |
| JPS5633020A (en) * | 1979-08-27 | 1981-04-03 | Hitachi Metals Ltd | Method and apparatus for deodorization |
-
1982
- 1982-05-13 DE DE19823217923 patent/DE3217923A1/en not_active Ceased
-
1983
- 1983-05-06 AT AT83104469T patent/ATE21833T1/en not_active IP Right Cessation
- 1983-05-06 EP EP19830104469 patent/EP0094573B1/en not_active Expired
- 1983-05-06 AU AU14312/83A patent/AU578229B2/en not_active Ceased
- 1983-05-06 DE DE8383104469T patent/DE3365814D1/en not_active Expired
- 1983-05-10 CA CA000427789A patent/CA1216810A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ATE21833T1 (en) | 1986-09-15 |
| DE3217923A1 (en) | 1983-11-17 |
| AU1431283A (en) | 1984-11-15 |
| DE3365814D1 (en) | 1986-10-09 |
| EP0094573B1 (en) | 1986-09-03 |
| EP0094573A1 (en) | 1983-11-23 |
| AU578229B2 (en) | 1988-10-20 |
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