Classifications

• • 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
  • B01D47/04—Separating dispersed particles from gases, air or vapours by liquid as separating agent by passing the gas or air or vapour through foam
• • 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
  • B01D53/46—Removing components of defined structure
  • B01D53/72—Organic compounds not provided for in groups B01D53/48 - B01D53/70, e.g. hydrocarbons
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
  • B27N1/00—Pretreatment of moulding material
• • 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
• • 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
  • C02F3/06—Aerobic processes using submerged 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
  • C02F3/12—Activated sludge processes
  • C02F3/1205—Particular type of activated sludge processes
  • C02F3/1231—Treatments of toxic sewage
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/26—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof
  • C02F2103/28—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof from the paper or cellulose industry
• • 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

Definitions

• the present invention relates to a purification and reco ⁇ very process of the type stated in the preamble of patent claim 1.
• the invention also relates to a device, designed to carry out the purification and recovery process accor ⁇ ding to the patent claim, which device is defined in more detail in the first device claim.
• this liquid is diluted with additional water in order to obtain a lower amount of formaldehyde and then of course large amounts of water must be subjected to a biological purification, which in most cases is done in large aerated ponds.
• the dwell time generally is 4-10 days. Possible chock loads with larger amounts of formal ⁇ dehyde may in such a process result in a large killing of microorganisms. The consequence of this is a sharply re ⁇ cuted purification effect for a long period of time.
• Document DE-25 47 675 relates to a process, in which there are just few points of similarity with the process and the device according to the present invention, since the wash ⁇ ing liquid in the main washing phase principally only is fed through a circuit between the scrubber and the biore- actor. It is true that there is an additional cycle for a distribution device 4, upstreams of the bioreactor, but this cycle is not really similar to the present inven ⁇ tion, since this cycle only is used to circulate a small flow of washing liquid to and from a sludge separator 6. Also, distribution device 4 is not really similar to the present invention, and there is no suggestions in this document of a heat exchange between polluted discharged air and fresh air.
• One object of the present invention is to provide :. pro ⁇ cess and a device, which are characterized by a satisfac ⁇ tory cleaning of air as well as water, which pass through a production plant. Another object is to obtain such a cleaning quickly, in a realiable, controllable and eco ⁇ nomically advantageous way. An additional object is to, despite ?n im nv p rl cleaning of the process air as well as the process water, lower the energy requirement for the production process itself. Finally, the present in ⁇ vention is supposed to develop the state of the art in this field also in additional respects.
• the polluted air flows via an outlet duct 2 to a scrubber 3, in which the air is cleaned with water," which is fed via a feed duct 4 .and is finely divided by means of spray-nozzles 5 in the upper area of the scrub ⁇ ber.
• the air, cleaned in this way, leaves the scrubber via an outlet 6 and e.g. a chimney 7, which leads out into the atmosphere.
• said sc r ubber is combined with a heat exchanger 8 , through which fresh air is fed into source 1 via an inlet duct 9.
• the Fresh air which may have the same tempera ⁇ ture as the ambient air, is heated in heat exchanger 8, and in this way the heating requirement for the fed air is reduced considerably.
• the condensation of water vapor from the polluted air is increased and the scrub ⁇ ber water will be somewhat colder.
• These two effects re ⁇ sult to an increased extent in an absorption of volatile contaminants in the scrubber water, the cleaning effect being improved.
• a certain temperature stabiliza ⁇ tion by means of a device (not shown) in the duct up- streams of the biological purification, may neverthe ⁇ less be required in order to provide the microorganisms with stable conditions .
• the cleaning water leaves scrubber 3 via a coarse separa- tor 10, designed to separate mainly coarser solid par- .ticles. '
• the cleaning water roughly purified in this way, then is fed via a duct 11, having a built-in pump 12, to a water tank 13, to which also a fresh water-duct 14 is connected, having a built-in pump 15, as well as the above-described feed duct 4 having built-in pump 16.
• a feed duct 17 issues, having a built- in pump 18 and leading preferably first to a particle se ⁇ parator 19, designed mainly for accompanying finer fibers and after that to a biological purification plant, gene ⁇ rally designated 20.
• the latter comprises, in the flow direction of the water, mainly a mixer 21 with connected store tanks 22 and 23, which contain nutrient salts and/ or pH-adjusting means etc. for a biological treatment of the water, which subsequently is fed into a bioreactor 24 with filling bodies 25, in and on which microorganisms are cultivated, which are to decompose at least some of the contaminants in the water, particularly formaldehyde.
• the bottom of the bioreactor is connected to an aeration device 26 having nor-zle ⁇ 27.
• v n * ar fo ⁇ instance placed along the bottom of the bioreactor and fed with air via a feed duct 28 with a fan 29. From these nozzles finely divided air bubbles issue, which provide the microorga ⁇ nisms with oxygen.
• Duct 17 leads in the bioreactor sub ⁇ sequently to a separator 30 for biosludge and reaches fi- - nally via an additional pump 31 water tank 13 again.
• Such a device functions in the following way:
• the scrub ⁇ ber several processes take place simultaneously, as has been mentioned above. Partly heat is transferred from the heat exchanger and the hot, moist and polluted gas to the cold fresh air stream to the drier or the like. Partly an absorption of organic gaseous substances takes place to the circulating water, which is sprayed into the scrub ⁇ ber. Thanks to the comparatively low temperature of the polluted air and water a satisfactory absorption of said organic gaseous substances is obtained. Simultaneously the amount of particles in the air is reduced substanti ⁇ ally, since also most particles are absorbed by the wa- ter. After the described treatment the purified air is discharged through chimney 7. It now contains a small amount of said organic substances, e.g.
• the water flow from tank 13 to purification plant 20 ge ⁇ nerally corresponds to the amount of liquid condensed in the scrubber plus possibly added fresh water.
• the formal ⁇ dehyde contents of this flow is often 200-300 mg/1.
• a wa ⁇ ter which has such a high amount of formaldehyde usually is considered very difficult to treat.
• the suspended amount of fiber is separated by means of e.g. flotation.
• the p -value of the water is adjusted to about 7 by adding e.g. sodium hydroxide through the mixer 21, through which also the required amount of nutrient salts is added, which the microorga ⁇ nisms in the bioreactor, connected downstreams, need according to a calculation.
• the microorga ⁇ nisms grow on filling bodies of a type known per se, e.g. those which AB Carl Munthcr sells, called Euroform.
• the filling bodies are lowered into the bioreactor and can quickly and simply be exchanged, in case and when this is required.
• the filling body material preferably is desi ⁇ ned in such a way, that the finely divided air bubbles, issuing from nozzles 27, are distributed evenly in the reactor vo ⁇ lume.
• h short dwell time will bo sufficient, e.g. 3-8 hours, provided microorganisms are used, which are specialized as to their capacity to decompose the specific Organic contaminants encountered.
• the reactor size is in a case
• the reactor volume is estimated to be 150 m .
• the reactor is designed in this way and. the vari ⁇ ous processes can be controlled, the reactor can be ope ⁇ rated with a very high load, with satisfactory results despite the short dwell times.
• the discharge of formaldehyde which takes place via chim ⁇ ney 7, can be controlled and influenced by varying either the liquid flow through scrubber 3 or the contaminant con ⁇ tents in the scrubber liquid.
• the liquid flow is kept constant.
• the formaldehyde contents in the gas, which is discharged through chimney 7 is increased above the allowed limit, that partial stream which is fed to the biological purification plant is increased.
• the re ⁇ moval of water, from tank 13, with a high formaldehyde contents via duct 17 increases and to the same extent the amount of purified water, returned to tank 13 via duct 41, increases.
• the scrubber liquid in scrubber 3 will have a lower amount of contaminants than before.
• the physical equilibrium between the formaldehyde in the gaseous phase and the formaldehyde in the water phase will then be influenced in such a direction, that more formaldehyde will be absorbed by the liquid.
• Biological purification plant 20 must of course have such dimensions, that the increased load will be taken care of. However, a certain overload can easier be accepted, pro ⁇ vided the incoming liquid flow has a lower contents of formaldehyde, which automaticly will result due to the above-described change.
• control/detection described above of the amount of the remaining organic contaminants in the discharged air can be carried out by means of a control element 34, con ⁇ nected in the discharged air-path 6,7, the outsignal of said control element being sent to a guide element 35, de ⁇ signed to influence the liquid circuit through the purifi- cation plant.- Also, in order to take care of emergencies with temporarily extremely high contents of contami ⁇ nants in the air from the drier, duct inlet 17 to the tank and duct outlet 4 from the tank can be short-cir- • . cuited via a valve 36.
• the bioreactor can include a buffer space, e.g. by oversizing the bioreactor, or such a space 38 can be pro ⁇ vided downstreams of the reactor.
• the object of such a space is to via pump 31 temporarily increase the dis ⁇ charge of cleaned water and at the same time let pump 18 continue to feed polluted water into the purification plant with an unchanged speed.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Microbiology (AREA)
• Organic Chemistry (AREA)
• Water Supply & Treatment (AREA)
• Hydrology & Water Resources (AREA)
• Biodiversity & Conservation Biology (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Analytical Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Biomedical Technology (AREA)
• Toxicology (AREA)
• Manufacturing & Machinery (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Treating Waste Gases (AREA)
• Biological Treatment Of Waste Water (AREA)
• Micro-Organisms Or Cultivation Processes Thereof (AREA)
• Separation Of Gases By Adsorption (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 1990
  • 1990-07-13 SE SE9002429A patent/SE466735B/sv not_active IP Right Cessation
• 1991
  • 1991-06-27 PL PL29759991A patent/PL297599A1/xx unknown
  • 1991-06-27 EP EP19910913304 patent/EP0539459A1/en not_active Withdrawn
  • 1991-06-27 BR BR9106639A patent/BR9106639A/pt unknown
  • 1991-06-27 WO PCT/SE1991/000465 patent/WO1992000792A1/en not_active Application Discontinuation
  • 1991-06-27 AU AU82242/91A patent/AU644009B2/en not_active Ceased
  • 1991-06-27 JP JP91512394A patent/JPH05508583A/ja active Pending
  • 1991-06-27 CA CA 2086927 patent/CA2086927A1/en not_active Abandoned
• 1993
  • 1993-01-04 FI FI930002A patent/FI930002A/fi not_active Application Discontinuation

Non-Patent Citations (1)

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