EP0377713A1 - Dispositif et procede pour la purification d'eaux usees - Google Patents

Dispositif et procede pour la purification d'eaux usees

Info

Publication number
EP0377713A1
EP0377713A1 EP19890907080 EP89907080A EP0377713A1 EP 0377713 A1 EP0377713 A1 EP 0377713A1 EP 19890907080 EP19890907080 EP 19890907080 EP 89907080 A EP89907080 A EP 89907080A EP 0377713 A1 EP0377713 A1 EP 0377713A1
Authority
EP
European Patent Office
Prior art keywords
net
water
characterized gekennzeich
adsorbent material
pretreatment
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.)
Withdrawn
Application number
EP19890907080
Other languages
German (de)
English (en)
Inventor
Wilfried Dolkemeyer
Karin Schmidt
Hans Gierlich
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rheinbraun AG
Original Assignee
Rheinische Braunkohlenwerke AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Rheinische Braunkohlenwerke AG filed Critical Rheinische Braunkohlenwerke AG
Publication of EP0377713A1 publication Critical patent/EP0377713A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them

Definitions

  • the present invention relates to the removal of adsorbable impurities, in particular organic impurities, by means of a device in which there is a layer of adsorbent material which has preferably been pretreated with steam and / or water.
  • Examples include biological processes which are used primarily to aerobically remove organic contaminants and nitrogen-containing contaminants.
  • Reverse osmosis is also used to purify waste water (DE-OS 35 43 661, EP-A-0 229 414).
  • Adsorptive processes are also important for wastewater treatment.
  • DE-PS 24 18 169 and DE-PS 28 19 572 used as an adsorbent.
  • DE-OS 33 35 994 a filter cartridge system is used which contains a suitable adsorbent.
  • DE-OS 34 01 867 an adsorbent resin is used.
  • Carbon materials are also used as adsorbents.
  • the pre-cleaned water is sprayed into an active carbon adsorption tower with simultaneous air supply.
  • activated carbon preferably carbon black from gasification plants, is pressed with a flocculant and a polymer into pellets which are introduced into the waste water with stirring.
  • EP-A-0 134 271 discloses a wastewater treatment process according to which wastewater is moved upwards through a coal bed, the coal bed expanding by approximately 30%.
  • landfill leachate from hazardous waste landfills contains a different composition of impurities than leachate from domestic waste landfills (Rubbish and Waste, 2, 1988, pp.67-71).
  • the proportions of organic impurities are usually higher in the latter.
  • FIGS. 1, 2 and 3 show results for the reduction of the COD value in a laboratory device.
  • FIGS. 4 and 5 show results with a technical device.
  • Figure 6 shows results with a high temperature coke.
  • FIGS 1, 8 and 9 represent experiments in which the coke was not pretreated.
  • FIGS. 10-13 represent tests in which surface-active substances were added to the pretreatment water.
  • FIG. 14 shows an example of a device according to the invention.
  • Figures 15-17 represent loading, operation and transport of devices according to the invention.
  • the device according to the invention is a container in which there is a water-permeable, sieve-type installation above the container bottom, above which adsorbent material is arranged, with purified water flowing off through at least one outlet or overflow.
  • the container can have any spatial shape, that is, it can be cylindrical and round, square, rectangular / trapezoidal or can also consist of composite spatial shapes, such as, for example, expanding trapezoidally in the upper part, but being rectangular or rectangular below.
  • the container which is generally closed at the bottom but provided with at least one drain, has a sieve-like, rust-like installation in the lower region above the container bottom.
  • This permeable part can take up the entire surface of this floor or only a part of the surface, in the limit case it can only cover the surface before the drain.
  • the layer of adsorbent material rests on the sieve-like base.
  • the sieve-like base has the function of letting the water flowing out of the adsorption layer pass, so that it passes beneath it via at least one Drain can be removed from the container.
  • the sieve bottom can have any configuration, such as a wire mesh, rods, a perforated metal plate or any other arrangement. For example, it can also have elevations or depressions.
  • the device according to the invention can consist of different materials as are customary in container construction, ie of steel, cast iron, stainless steel, plastics, reinforced concrete, composite materials and others
  • Another preferred embodiment of the pretreatment is carried out by evacuation.
  • the evacuation can take place in such a way that a vacuum is applied to the container containing the coke and / or the activated carbon and the liquid, preferably water, is then allowed to flow into the adsorption material.
  • the liquid preferably water
  • the removal of the gas adhering to the adsorbent material is an important preferred embodiment of the present invention, as is evident from the tests carried out. Can be very beneficial. ie already carried out, the degassing by treatment with steam or hot water or both, also in combination with a degassing by evacuation. Degassing and mixing with water can also be carried out in the same way, that the adsorption material, such as finely divided coke or activated carbon, are sucked in with the water jet of a water jet pump. Another degassing process is the cycle mode with water.
  • the wastewater to be cleaned itself can also be used here.
  • the pH of the circulating water should rise to values> 10, preferably> 12, during the advantageously multi-hour cycle. Surface-active substances can also be added to the water used in the pretreatment.
  • the increase in pH in the alkaline or strongly alkaline range is undesirable, for example when contaminants have to be removed from groundwater.
  • the pH can either be adjusted by adding acids or one works with an acid-containing adsorbent, such as those containing SO ? contained in the cleaning of flue gases.
  • activated carbon or coke for example, which is loaded by flue gas cleaning, can subsequently be used for wastewater treatment.
  • the pretreatment time can be shortened considerably.
  • the surface-active agents should meet the following requirements: poor adsorbability,
  • Suitable classes of compounds are: anionic surfactants, n-alkyl sulfates
  • Alkyl sulfonates Alkylbenzenesulfonates, preferably with non-ionic surfactants containing n-alkyl groups (ethylene oxide adducts), may be mentioned as examples:
  • Fatty alcohol polyethylene glycol ether alkylphenyl polyethylene glycol ether, fatty acid polyethylene glycol ester.
  • 10 to 2000 ppm, preferably 20 to 1500 ppm and particularly preferably 20 to 1200 pp of surfactants are added to the pretreatment liquid.
  • the curves in FIGS. 10-13 were determined by way of example. For this purpose, 200 ml of a landfill leachate was stirred in a flask with 10 g of hearth furnace coke and the time course of the COD decrease was determined.
  • the water level in the container can be regulated by means of conventional regulating devices.
  • a very simple advantageous device is, however, the laying of the line for the draining water at such a height that the desired water level in the container can be set thereby.
  • a hose can be used as the drain line.
  • a fixed line can also be used.
  • the height of the drain line is advantageously adjustable so that any desired water level in the tank can be set.
  • a great advantage of the device according to the invention is its portability.
  • coke as an adsorbent in a coke production plant
  • it can be filled, treated with steam and / or hot water and / or water / steam mixture, transported to the landfill by truck, parked there and immediately in operation be taken.
  • the container can be taken to an incineration plant, to a landfill approved for this purpose or to a regeneration plant.
  • a preferred embodiment of the device is therefore that which is also customary for waste containers which are open at the top. This has the advantage that the trucks suitable for loading, unloading and transporting are available.
  • Any adsorbing material can be used in the method according to the invention, but preference is given to materials based on carbon, in particular coke, since these are considerably more economical than activated carbon, for example.
  • a suitable coke is e.g. Oven coke obtained from lignite, in particular from Rhenish lignite, but also coke and hard coal coke made by other processes are suitable according to the invention.
  • Other adsorbents can also be used, e.g. based on SiO_ or aluminum silicate or Al-O -, - or plastic, e.g. Silica gels, clays, bleaching earths, molecular sieves, ion exchangers and magnesium oxide.
  • the applicant has found that treating it with gases and / or liquids, if necessary accompanied by previous evacuation before putting into operation, brings substantially better results than without this pretreatment.
  • the preferred gas is water vapor
  • the preferred liquid is water and / or a water / steam mixture.
  • the adsorbent material is filled with a gas, water, in particular hot water and / or water / steam mixture in the event of heating.
  • the temperature range in which the coke is brought by heating is 20-200 ° C, preferably 50-180 ° C and particularly preferably 75-140 ° C.
  • additional treatment with liquid e.g. Water possible before heating.
  • the gas or the steam or the liquid or gas / liquid mixture is generally below the sieve-like one Installation initiated. However, initiation is also possible at other points.
  • the treatment time is generally 1 minute to 20 hours, preferably 10 minutes to 10 hours, particularly preferably 10 minutes to 5 hours. However, this information is not to be regarded as limiting, but rather as preferred embodiments.
  • the waste water can be passed through the adsorption layer from top to bottom, a water level generally being maintained which is somewhat higher than the adsorption layer itself.
  • a mode of driving can also be selected in which the waste water is passed from bottom to top through the device according to the invention.
  • the flow rate of the water flowing through the adsorption layer is> 0 to 1 m / h, preferably 0.01 to 0.8 m / h, particularly preferably 0.05 to 0.5 m / h.
  • the residence time of the waste water in the coke layer is 1 minute to 10 hours, preferably 5 minutes to 7 hours, particularly preferably 10 minutes to 5 hours.
  • the wastewater treatment temperature is - 0 to 45 ° C, preferably 5 to 35 ° C.
  • the specified temperature ranges are to be regarded here as operating temperatures, it having to be taken into account that the pretreatment described may initially result in a higher temperature.
  • the adsorbent material can also be pretreated as described before being filled into the device.
  • a grain size of the adsorbent material from 0.01 to 100 mm, preferably from 0.05 to 20 mm and particularly preferably from 0.05 to 5 mm.
  • the cheapest grain size also depends in part on the adsorption material used. For example, when using carbon black from gasification plants to produce synthesis gas, for example by shell or Texaco gasification, the grain size is usually 0.3 to 1 ⁇ m. When using such a carbon black, good results are obtained even without steam pretreatment. It is sufficient to use the soot filtered off from the aqueous suspension in the device according to the invention.
  • Very suitable adsorbent material is fine coke with the known grain size.
  • the concentration of organic impurities (COD) and the concentration of adsorbable organic halogen compounds (AOX) can be considerably reduced by the process according to the invention.
  • the device according to the invention and the method according to the invention are of particular importance for the cleaning of landfill leachate.
  • the device and method can be operated on site according to the invention and the water pumped onto the device, for example from percolation shafts, can be cleaned directly in the landfill area.
  • the water purified in this way can also be used for other cleaning processes, e.g. be sent to a sewage treatment plant.
  • cleaning methods corresponding to the prior art can also be combined with the method according to the invention, such as, for example, pretreatment by settling, sedimenting, filtering, precipitating, flaking, degassing, aerating, sterilizing and emulsion splitting or the use of ion exchangers.
  • FIG. 1 shows laboratory tests in which> 0 - 80 ml of landfill leachate per g of adsorbent are passed over it at a flow rate of 0.5 m / h, a residence time of approx. 27 minutes and a temperature of 23 ° C.
  • a hearth coke made from Rhenish brown coal was used (surface area approx. 250 m 2 / g).
  • the oven coke was through 4 hours Circular procedure of wastewater to be cleaned (without the addition of surface-active agents) over the coke has been pretreated;
  • the apparatus was generally carried out by flowing the waste water through a pipe filled with adsorbent material.
  • the test wastewater contained a concentration (COD) of 1470 mg / l wastewater of organic impurities in test 1 and a quantity of 860 mg / l in test 2.
  • the straight lines indicate the remaining COD value after cleaning in accordance with the invention with different amounts of wastewater passed through the cleaning device.
  • the curves show that the COD values can be reduced to 100-200 mg and below, the adsorption capacity decreasing with increasing load, accompanied by an increase in the COD in the purified wastewater.
  • Wastewater pre-cleaned in this way can, if necessary, be further cleaned in sewage treatment plants or, if permissible, can be fed directly into water.
  • FIG. 2 Analog tests are shown in FIG. 2 which were carried out at a flow speed of 0.3 m / h and an oven coke made from Rhenish lignite. The pretreatment was carried out by evacuation and subsequent filling with water.
  • FIG. 3 shows analogous tests with a landfill leachate (test numbers DW 38, 39) and a hard coal coke.
  • the COD value of the waste water used was 1690 mg / 1.
  • the flow velocities were 0.1 m / h (DW 39) and 0.2 m / h (DW 38).
  • the residence times were 2 hours (DW 38 and 39).
  • FIG. 4 shows tests in a technical installation with waste water from a special landfill. An oven coke was also used, which was pretreated with a steam / water mixture for 2 hours. The input COD values were 1045 mg / 1 and 1100 mg / l (flow rate: 0.3 m / h). These results also show that excellent results can be obtained with the method according to the invention.
  • FIG. 5 shows tests on an industrial scale with a large container as the device according to the invention (flow rate: 0.2 m / h, residence time: 3 hours).
  • the pretreatment corresponded to that in FIG. 1.
  • the COD values in the feed are 1380 and 1300 mg / l.
  • the waste water came from a household waste landfill. As the curves show, the COD values could be reduced to ⁇ 100 mg / 1 COD.
  • FIG. 6 shows an experiment which was carried out like the experiment according to FIG. 1, but in which a high-temperature lignite coke from the GDR was used (surface area: 200-250 m 2 / g).
  • FIGS. 7, 8 and 9 show experiments which corresponded to experiments 1, 3 and 6, but without pretreating the adsorbent.
  • the following table shows the residual amounts of organic impurities in the wastewater according to FIGS. 1-9 after cleaning via various adsorbents.
  • the flow velocities were varied between 0.1 m / h and 0.5 m / h.
  • the initial COD values are given in mg / 1 waste water.
  • the remaining COD values in the treated wastewater are shown when the adsorbents are loaded with 10 ml / g adsorbent and 50 ml / g adsorbent. All tests were carried out at ambient temperature.
  • experiment 4 the oven coke was used as an adsorbent.
  • the pretreatment consisted of a 2 hour treatment with a steam-water mixture. The results were particularly good with this pretreatment.
  • tests 7 8 and 9 tests 1, 3 and 6 were repeated, but without pretreatment, i.e. the wastewater to be cleaned was passed directly over the untreated adsorbent.
  • the preheating coke is wetted by the pretreatment liquid as a prerequisite for the adsorption capacity of the coke when the surfactant is added.
  • FIG. 14 shows a preferred embodiment of a device (1) according to the invention. It has the shape and dimensions of a waste container.
  • the container has a water-permeable sieve bottom (3) above the container bottom (2).
  • the black layer represents the adsorbent bed.
  • the water layer (4) stands over the adsorbent bed. Waste water to be cleaned is fed in via (5).
  • (6) represents the space between the sieve plate and the container bottom.
  • An outlet is represented by (7).
  • the height of the water in (1) can be adjusted using the height-adjustable pipe bend (8).
  • the cleaned waste water runs off at (9).
  • (10) represents a water distribution system.
  • FIG. 15 shows an example of a system consisting of several devices (1-3) according to the invention.
  • the waste water is fed in via (4) and drawn off at (5) as purified water.
  • FIG. 16 shows an overview of the method according to the invention.
  • the adsorbent is delivered with the railway containers (1) and stored in (2).
  • the containers (3) according to the invention are filled from (2) and pretreated at (4) with steam and hot water and e.g. parked at a landfill where pumping from seepage shafts via (5) landfill leachate to the containers.
  • the outflowing purified water is collected in a collecting container (6), from which it can be transported, for example, to a sewage treatment plant.
  • the used adsorbent materials can be tipped over in a suitable landfill (7) or can also be transported to a regeneration.
  • FIG. 17 A further exemplary overview is shown in FIG. 17. Already pretreated adsorbent material is loaded from (1) into a truck (2) and transported to the devices (3) according to the invention.
  • Waste water (4) is directed onto the filled devices. Purified water is collected in container (5). Used adsorbent is dumped in landfill 6, for example.
  • the device and the method according to the invention represent a technically important further development of the state of the art, according to which effective wastewater treatment, in particular special highly polluted wastewater, can be carried out using inexpensive "disposable" adsorbents and in simple process steps how landfill leachate is possible.

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Sorption (AREA)

Abstract

L'invention concerne l'élimination d'impuretés adsorbables, notamment d'impuretés organiques, au moyen d'un dispositif renfermant une couche de matière adsorbante qui est de préférence prétraitée avec de la vapeur et/ou de l'eau.
EP19890907080 1988-07-08 1989-06-24 Dispositif et procede pour la purification d'eaux usees Withdrawn EP0377713A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3823127 1988-07-08
DE19883823127 DE3823127A1 (de) 1988-07-08 1988-07-08 Vorrichtung und verfahren zur reinigung von abwasser

Publications (1)

Publication Number Publication Date
EP0377713A1 true EP0377713A1 (fr) 1990-07-18

Family

ID=6358227

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890907080 Withdrawn EP0377713A1 (fr) 1988-07-08 1989-06-24 Dispositif et procede pour la purification d'eaux usees

Country Status (4)

Country Link
EP (1) EP0377713A1 (fr)
DD (1) DD285768A5 (fr)
DE (1) DE3823127A1 (fr)
WO (1) WO1990000525A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MD1155C2 (ro) * 1991-05-21 1999-10-31 Biochem Pharma Inc. Procedee diastereoselective de obţinere a cis-nucleozidelor, analogiilor şi derivaţilor optic activi, compuşi intermediari şi procedee de obţinere a lor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4327598C2 (de) * 1993-08-17 1997-01-30 Etc Engineering & Technology C Verwendung von Aktivkohle bei der Wasseraufbereitung, insbesondere für die Aufbereitung von Schwimm- und Badebeckenwasser
DE102011122170A1 (de) * 2011-12-16 2013-06-20 Aqua-Biocarbon Gmbh Festbettreaktor

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3701423A (en) * 1970-05-12 1972-10-31 Ecodyne Corp Method and apparatus for filtering a liquid
US3789991A (en) * 1971-08-23 1974-02-05 Z Krongos Water filter device
US4116825A (en) * 1975-11-28 1978-09-26 International Telephone And Telegraph Corp. Water purification methods
DE2650300A1 (de) * 1976-11-02 1978-05-03 A Dipl Chem Stauffer Verfahren zur entschwefelung von rauchgas und reinigung von abwasser
DE3105172A1 (de) * 1981-02-13 1982-08-19 Fried. Krupp Gmbh, 4300 Essen Verfahren zur reinigung von niedrig belastetem abwasser
DE8112613U1 (de) * 1981-04-29 1981-11-26 Behr, Jürgen, 4000 Düsseldorf Csb-abwasser-dekontaminationsgeraet
DE3221451A1 (de) * 1982-06-07 1983-12-08 Hoechst Ag, 6230 Frankfurt Behandlungsmittel fuer die reinigung von verschmutzten waessern
DE3321605A1 (de) * 1983-06-15 1984-12-20 Rütgerswerke AG, 6000 Frankfurt Verfahren zur reinigung von phenole und btx-aromaten enthaltenden abwaessern
DE3401867A1 (de) * 1984-01-20 1985-08-01 Didier-Werke Ag, 6200 Wiesbaden Verfahren zur entfernung von verunreinigenden, organischen, chemischen verbindungen aus waessern oder abwaessern
ZA851239B (en) * 1984-04-19 1985-09-25 Macdermid Inc Apparatus and method for removing dissolved metals from solutions containing same
DE3436453A1 (de) * 1984-10-05 1986-04-17 Bayer Ag, 5090 Leverkusen Verfahren zur reinigung von abwasser
AU589898B2 (en) * 1985-07-31 1989-10-26 Board Of Trustees Of The Leland Stanford Junior University A bioconversion reactor
DE8528576U1 (de) * 1985-10-08 1985-11-21 Metallgesellschaft Ag, 6000 Frankfurt Bewegliches Filter für Wasserreinigung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9000525A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MD1155C2 (ro) * 1991-05-21 1999-10-31 Biochem Pharma Inc. Procedee diastereoselective de obţinere a cis-nucleozidelor, analogiilor şi derivaţilor optic activi, compuşi intermediari şi procedee de obţinere a lor

Also Published As

Publication number Publication date
DD285768A5 (de) 1991-01-03
WO1990000525A1 (fr) 1990-01-25
DE3823127A1 (de) 1990-01-11

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