DD285768A5 - DEVICE AND METHOD FOR CLEANING WASTE WATER - Google Patents

Abstract

The invention includes an apparatus and method for purifying wastewater. The present invention relates to the removal of adsorbable contaminants, in particular organic contaminants, by means of a device in which there is a layer of adsorbent material, which has preferably been pretreated with steam and / or water. adsorbable impurities, organic; Device; Layer; adsorbing material; Steam; Water, pretreated}

Description

Characteristic of the known state of the art

By way of example, mention may be made of biological processes which serve, above all, to aerobically remove organic impurities and nitrogen-containing impurities by means of bacteria.

Only very few examples can be cited from the very extensive patent literature, such as DE-OS 2423844, EP-A-0 202 626, EP-A-0 143915, DE-PS 2512815.

Examples of anaerobic processes include:

DE-OS 3307796, EP 0046901, EP 0119430.

The reverse osmosis is used for the purification of wastewater (DE-OS 354 361, EP-A-0299414).

Also important in wastewater treatment are adsorptive processes. According to DE-PS 2418169 and DE-PS 2819572 Y-Al ₂ O _{3 is used} as the adsorbent. According to DE-OS 3335994 a filter cartridge system is used which contains a suitable adsorbent. According to DE-OS 3401867 an adsorber resin is used.

Coal materials are also used as adsorbents. Thus, DE-OS 3436453 discloses a two-stage process, wherein in a first stage powdered activated carbon is dispersed in the wastewater and then the solids are filtered off.

In a second stage, the prepurified water is sprayed into an activated carbon adsorption tower with simultaneous supply of air.

According to DE-OS 3221451 activated carbon, preferably carbon black from gasification plants, pressed with a flocculant and a polymer to pellets, which are added to the wastewater with stirring.

EP-A-0 134271 discloses a wastewater treatment process in which wastewater is moved from bottom to top through a coal bed with the coal bed expanding by about 30%.

Object of the invention

Despite the described extensive prior art, there is a need to clean wastewater in a simple, one-step, particularly economical process, the process should also allow the Reinigungsvor.tchtung site, so for example, set up on a landfill to operate and again transported away , A particularly important task here is to economically clean even heavily polluted waste water so far that they can be further purified in conventional treatment plants. In any case, increasing demands are expected for the purification of such wastewater. The current methods used for the purification of leachate are biological treatment with chemical / physical aftertreatment and reverse osmosis (see, for example, "Wastewater Technology", 1-2, 1988 pp. 34-38).

The type of impurities in seepage water can vary greatly depending on the waste material ion with which groundwater and surface water come into contact. For example, landfill leachate from hazardous waste landfills contains a different impurity composition than leachate from landfill sites (Waste and Waste, 2, 1988, p. 67-71). So the proportions of organic impurities in the latter are usually higher. Important impurities which must be removed are, for example, phenol and phenol derivatives, hydrocarbons or adsorbable organic halogen compounds (AOX).

Explanation of the essence of the invention

The Applicants have now succeeded in further developing the state of the art, in particular with regard to economy and ease of implementation, by a process for purifying wastewater, characterized in that a layer of adsorbing material is introduced into the device according to claims 1-7 the adsorbent material is pretreated by introducing hot gas and / or liquid and, in the case of heating with gas, is placed under water and / or a water / steam mixture, that the waste water to be purified is passed through the layer of adsorbent material and that the purified wastewater drains from the device.

-3- 285 768 Explanatory notes:

Figures 1, 2 and 3 illustrate results for reducing the COD value in a laboratory apparatus.

Figures 4 and 5 illustrate results with a technical device.

FIG. 6 shows results with a high-temperature coke.

FIGS. 7, 8 and 9 represent experiments in which no pretreatment of the coke took place.

Figures 10-13 illustrate experiments in which surface-active substances were added to the pretreatment water.

FIG. 14 shows by way of example a device according to the invention.

Figures 15-17 illustrate loading, operation and transport of devices according to the invention.

The device according to the invention is a container in which above the container bottom a water-permeable sieve-like installation is located, is arranged above the adsorbent material, wherein by at least one flow or

drained by overflow purified water.

Basically, the container may have any spatial form, so be cylindrical and round, square, rectangular., Trapezoidal or composite Haumformen wiez. B. expand trapezoidal in the upper part, but below square or rectangular.

The enumerated spatial forms are not to be regarded as limiting, for example, jeacch.

The generally closed at the bottom, but provided with at least one drain container has a sieve-like rust-like installation mounted in the lower region above the container bottom. This permeable part can occupy the entire surface of this floor or only a part of the area, in the limit it can only cover the area before the expiration.

The layer of adsorbing material rests on the sieve-like ground. The sieve-like bottom, in the case where the waste water is passed from top to bottom through the adsorbent material, has the function of allowing the water draining from the adsorbent layer to pass so that it can be withdrawn from the container below it via at least one drain. Basically, the sieve bottom may have any configurations, such as a sieve-like wire mesh, rods, made of a perforated metal plate or any other arrangements. For example, it can also have elevations or depressions.

If the wastewater is passed through the adsorption material from the bottom to the top, it can be fed in at the bottom by means of a feed and flow out of the device at the top via an overflow.

The device according to the invention may consist of different materials as they are customary in container construction, ie steel, cast iron, stainless steel, plastics, reinforced concrete, composite materials u. a.

In order to avoid or reduce corrosion, it is desirable to provide corrosive materials with a protective coating or paint.

In order to reduce channeling in the adsorption layer and on the container walls, it is advantageous to provide suitable internals for flow conduction in the container, such as baffles to the container wall.

Since it has proved to be very advantageous to heat the adsorption material with gases, in particular steam and / or liquids, in particular water and / or water / steam mixtures or hot water, at least one supply device for steam and / or or water is provided, preferably in the lower region, wherein the drain located in the container can be used by connection to a steam and / or hot water line for this purpose.

However, a supply of steam and / or water is also possible from top to bottom according to the invention.

A further preferred embodiment of the pretreatment is carried out by evacuation. The evacuation can be carried out by applying vacuum to the containers containing the coke and / or the activated carbon and then allowing the liquid, preferably water, to flow into the adsorption material. However, it is also possible first to wet or cover the adsorption material with the liquid and then to apply a vacuum.

The removal of deep adhering gas to the adsorbent material is an important preferred embodiment of the present invention, as apparent from the experiments carried out. Very advantageous, as already stated, the degassing by treatment with steam or hot water or both, even in combination with a degassing by evacuation. Likewise, the degassing and mixing with water can be carried out in such a way that the adsorption material, such as. B.

be sucked finely divided coke or activated carbon with the water jet of a water jet pump. Another degassing process is the circulation method with water. Here, the wastewater itself can be used. In this case, the pH of the circulating water should increase to values of 10, preferably 12 during the advantageously several-hour circulation mode. Surfactants may also be added to the water used in the pretreatment.

In certain cases, increasing the pH to the alkaline or strong alkaline range is undesirable, for example, when contaminants are to be removed from groundwater. Here, the pH can be adjusted either by the addition of acids or you work with an acid-containing adsorbent, wio z. B. with those containing SOj from the purification of flue gases.

Accordingly, for example, activated carbon or coke, which are loaded by flue gas cleaning, then be used for wastewater treatment.

By adding surface-active agents to the pretreatment liquid, especially to water, the pretreatment time can be shortened considerably.

The surface-active agents according to the invention should fulfill the following requirements:

weak adsorbability,

surfactant properties in alkaline,

good biodegradability,

Activity at low dosage,

low foaming.

Suitable classes of compounds are:

anionic surfactants

n-alkyl

alkylsulfonates Alkylbenzenesulfonates, preferably with n-alkyl groups, nonionic surfactants, (ethylene oxide adducts), may be mentioned by way of example: Fatty alcohol polyethylene glycol ethers, Alkylphenyl polyethylene glycol ethers, Fatty acid Polyethylenglykolester. According to the invention, the pretreatment liquid is 10-2000 ppm, preferably 20-1600 ppm, and particularly preferred

20-1200 ppm of surfactants added.

By way of example, the curves in FIGS. 10-13 were determined. For this purpose, each 200ml of landfill leachate with

10g Herdofenkoks stirred in a flask and determines the time course of the COD decrease.

The water level in the container can be regulated by conventional control devices. A very simple advantageous The device, however, is the laying of the pipe for the draining water at such a height as to cause the water to flow through it

desired water level can be set in the container. As a drain line in this case a hose veiwendet were.

However, it can also be used a fixed line. Advantageously, the height of the drain line is adjustable, so that each

desired water level in the container can be adjusted.

A great advantage of the device according to the invention lies in the transportability. So this can for example at Use of coke are used as an adsorbent in a coke-making plant, with steam and / or hot water

and / or water / steam mixture to be treated, you ^r ch transported a truck to the landfill, to be taken in Setrieb parked there andsoforth. After saturation of the adsorbent, the container may be taken to an incinerator, to a landfill approved for this purpose, or to a regeneration facility.

A preferred embodiment of the device is therefore the one that is common in open-topped waste containers

is. This has the advantage that the trucks suitable for loading and unloading and transporting are available.

In the method of the invention, any absorbent material may be used, but preferred Coal-based materials, in particular Kokso, because they are much more economical than, for example, activated carbon. On

suitable coke is e.g. from lignite gewannener, in particular from Rhenish lignite produced Herdofenkoks, but also prepared by other methods cokes and coal coke are suitable according to the invention. Furthermore, other adsorbents can be used, e.g. B. on SiCV or aluminum silicate or AI2O3 · or plastic base such. B.

Silica gels, clays, bleaching earths, molecular sieves, ion exchangers and magnesium oxide. In particular, in the case of the use of coke, the Applicant has found that treating it with gason and / or Liquids possibly accompanied by previous evacuation before commissioning brings much better results than without them Pretreatment. Preferred gas is water vapor, preferred liquid is water and / or water / steam mixture. After Treatment becomes the adsorbing Matertal irr; Case of heating with a gas, with water, especially hot water

and / or water / steam mixture.

The temperature range in which the coke is brought by heating is 2O-2OOX, preferably 50-180 ° C and especially

preferably 75-140 ° C. According to the invention, an additional treatment with liquid, for. For example, water is possible before heating.

The gas or the vapor or the liquid or gas / liquid mixture is generally below the sieve-like

f-inbaus initiated. The initiation is also possible in other places. The treatment time is generally 1 minute to 20 hours, preferably 10 minutes to 10 hours, more preferably 10 minutes to 5 hours. However, this information is not limiting, but preferred *? To view embodiments.

In operation of the device, the wastewater can be passed from top to bottom through the adsorption layer, wherein in

In general, a water level is maintained, which is slightly higher than the adsorption itself. But it can also be a

Mode of operation can be selected, in which the wastewater 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

0.8m / h, more 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, more preferably 10 minutes to 5 hours.

The wastewater treatment temperature is SO to 45 ⁰ C, preferably at 5 to 35 ° C. Here are the specified Temperature ranges to be regarded as operating temperatures, taking into account that described by the Pretreatment may initially be a higher temperature. According to the invention, the adsorbent material also before

pretreated into the device as described.

It is advantageous according to the invention to work with a particle size of the adsorption material of 0.01 to 100 mm, preferably

from 0.05 to 20 mm, and more preferably from 0.05 to 5 mm. However, the most favorable grain size also depends in part on the adsorbent material used. For example, when using soot from gasification plants for the production of

Syngas z. B. by Sh ill or Texaco gasification, the grain size usually 0.3 to 1 mm. When using such a carbon black good results are obtained even without steam pretreatment. It is enough, from the

aqueous suspension filtered off soot into the device according to the invention.

Very suitable adsorbent material is Feinstkoks with the known, this corresponding grain size. The inventive method, the concentration of organic impurities (COD) and the concentration

be significantly reduced in adsorbable organic halogen compounds AOX.

The device according to the invention and the method according to the invention are of particular importance for the Cleaning of landfill leachate. Here, as described, according to the invention device and method on site

be operated and, for example, from seepage shafts on the device pumped water directly in the landfill area cleaned. Depending on the requirement, the water purified in this way can also be used for other cleaning processes, such as cleaning. B. one

Wastewater treatment plant to be supplied. Of course, other prior art cleaning methods with the

be combined according to the invention, such as pretreatment by sedation, Sedhnentieren,

Filtration, precipitation, flocculation, degassing, aeration, sterilization and demulsification or the use of ion exchangers. embodiments

The invention ^{1 will} now be explained in more detail with the help of the figures.

FIG. 1 shows laboratory experiments in which> 0-80 ml of landfill leachate per g adsorbent are passed over it at a flow rate of 0.5 m / h, a residence time of about 27 minutes and a temperature of 23 ^° C. a Herdofenkoks from Rhenish brown coal used (surface about 25OmVg). The hearth furnace coke had been pretreated by 4 hours of Krelslauffahr wayo to be cleaned wastewater (without the addition of surfactants) on the coke.

The experimental apparatus was generally carried out by flowing the wastewater through a filled with adsorbent tube.

The feed wastewater contained in experiment 1 a concentration (COD) of 1470 mg / l. Wastewater on organic pollutants, in trial ?. a mengo of 860mg / l.

The straight lines indicate the remaining COD value after cleaning according to the invention with different amounts of wastewater conducted through the cleaning device.

The curves show that the COD values can be lowered down to 100-200 mg and below, with increasing load the adsorption capacity decreases, accompanied by an increase in the CSS in the treated wastewater.

Such pre-treated wastewater can possibly be further purified in sewage treatment plants without any problem or, if permissible, discharged directly into bodies of water.

FIG. 2 shows analogous experiments which were carried out at a flow rate of 0.3 m / h and a hearth furnace coke made of Rhenish brown coal. The pretreatment was carried out by evacuation and subsequent filling with water.

FIG. 3 shows analogous experiments with a landfill leachate (test numbers DW38, 39) and a hard coal coke. The COD value of the wastewater used was 169 mg / l. The flow rates were 0.1 m / h (DW39) and 0.2 m / h (DW38). The residence times were 2 hours (DW38 and 39).

In Figure 4 experiments are shown in a technical system with a wastewater from a special landfill. It was also used a hearth furnace coke, which was pretreated for 2 hours with a steam / water mixture. The input COD value was 1045 mg / l 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.

In Figure 5, experiments are on an industrial scale r \ ^'<'. Nom large container shown as an inventive device

(Flow rate: 0.2m / h, residence time: len). The pretreatment corresponded to that in FIG. 1. The COD values in

Feedstock is 1380 and 1300mg / l.

The wastewater came from a household waste dump.

The COD values could, as the curves show, be reduced to <100 mg / l COD.

FIG. 6 shows an experiment which was carried out as in the experiment according to FIG. 1, but in which a high-temperature lignite coke from the GDR was used (surface area 200-25 μmVg).

In the figures 7,8 and 9 experiments are shown, which correspond to the experiments 1,3 and 6, but without pretreatment of the adsorbent.

In the following table, the residual amounts of organic impurities in the wastewater according to Figures 1-9 are given after purification over different adsorbents. The flow rates were varied between 0.1 m / h and 0.5 m / h. The initial COD values are given in mg / l wastewater. In the two right-hand columns, the remaining COD values in the treated wastewater are given for a load of the adsorbents with 10 ml / g adsorbent and 50 mg / g adsorbent. All experiments were carried out at ambient temperature.

The Vorholung of the adsorbent was carried out in the experiments 1,2,3,5 and 6 by several hours of circulation mode a bestimmton amount of wastewater through the adsorbent.

In experiment 1, effluents with 1470 mg and 860 mg COD in wastewater and a flow rate of 0.5 m / h were investigated.

At 10ml load residual COD values of up to 60mg were reached.

Similarly good results with 10 ml load were also achieved in experiment 2 with a slightly lower flow rate of 0.3 m / h, while the values at 50 ml / h substantially improved over experiment 1.

In experiment 3 was worked at 0.1 m / h and 0.2 m / h flow rate.

In contrast to the experiments 1 and 2 was worked with a hard coal coke.

Again, good results were obtained, albeit at low flow rates.

In experiment 4, the hearth furnace coke was used as adsorbent. The pretreatment consisted of a 2-hour treatment with a steam-water mixture. The results were particularly good at this pretreatment.

In experiment 5 was worked on an industrial scale. The pretreatment corresponded to experiment 1.

In experiment 6, a high-temperature lignite coke was used. At a flow rate of 10 ml / g, worse results were obtained than in Experiment 1, but not at a load of 50 ml / g.

In experiments 7, 8 and 9, the experiments became 1.? and 6 repeatedly, but without pretreatment, d. H. The wastewater to be treated was passed directly over the untreated Ad jrbens.

The results were significantly worse at both 10 mg / g and M ml / g load than in trials 1,3 and 6.

table

Experiment no. flow mg / 1 organic I In the purified wastewater speed impurities remaining COD value m / h in the wastewater in mg / 1 at different before cleaning Loading of the adsorbent in ml / g adsorbent 10ml 50ml

1 0.5 147O ¹ 86Ο ² 80 ³ 60 ⁴ 980 400 2 0.3 1145 ^s 960 ^β 80 ⁷ 70 " 370,330 3 0.1 (DvV 39) 0.2 (DW 38) 1690 1690 90 70 380 390 4 0.3 1100 50 290 5 0.2 1400 1OmVt 100 5OmVt 860 6 0.5 1470 860 270 200 960 550 7 (such as 1) 0.5 1470 860 450,330 > 1200 750 8 (like 3) 0.1 (DW 40) 0.2 (DW 33) 1690 1690 360 450 840> 1200 9 (as 6) 0.5 1470 860 510 380 1160 740

1 of them 323mg AOX; 2 of them 189mcAOX; 5 of them 401 mg AOX; 6 of which 336 mg AOX;

3 of them 12mg AOX; 4 of them 9mg AOX; 7 of which 9.6mg AOX; 8 of them 8,4mgAOX.

The results are explained in more detail in FIGS. 10-13.

In FIG. 10, 50 ppm of a surfactant having the characteristic ESP-5433 was added to the pretreatment water.

If one considers the time in which the COD value has decreased from originally 200 ppm to 800 ppm, it is found that this decrease without surfactant is reached after about 53 minutes, with surfactant already at 38 minutes.

The use of the hearth furnace coke through the pretreatment liquid as a prerequisite for the adsorption capacity of the coke is accordingly much faster with the addition of the surfactant.

This is apparent in the experiment from the fact that the adsorption of the relatively small adsorbent COD fraction in the wetting test with the addition of the surfactant is much faster than without this.

With surfactant 800 ppm COD are achieved after 12 minutes, without surfactant after 23 minutes. Similar results are obtained with the surfactant ESD-151 (FIG. 12). At BOO ppm addition, 800 mg COD are achieved after 35 minutes, without addition after 54 minutes. In FIG. 13, with 1000 ppm of surfactant additive, 800 ppm of COD are achieved after 10 minutes, without surfactant after 23 minutes. 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 above the adsorbent bed. Wastewater to be cleaned is supplied via 5. FIG. 6 illustrates the space between the sieve bottom and the container bottom. An outlet is shown by FIG. Due to the height-adjustable cable bend 8, the water level can be adjusted in 1. The purified wastewater drains off at 9. 10 illustrates a water distribution system.

FIG. 15 shows by way of example an ai-s of a number of devices 1'-3 'according to the invention. The wastewater is supplied via 4 'and withdrawn at 5' as purified water. In device 1 'the removal of spent adsorbent is shown, in device 3' the filling with fresh adsorbent. FIG. 16 shows an overview of the method according to the invention. The adsorbent is delivered by railroad 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 set down, for example, at a landfill, where seepage shafts are pumped onto the containers via 5" landfill leachate. The effluent purified water is collected in a sump 6 "from which it may be transported, for example, to a sewage treatment plant .. The spent adsorbent materials may be dumped to a suitable landfill 7" or may be transported to regeneration. Another exemplary overview is shown in FIG. 17. Already pre-treated adsorbent material is loaded from 1 "into a truck 2" and conveyed to the devices 3 "'of the invention. Wastewater 4" is directed onto the filled devices. Purified water is collected in vessel 5 ". Used adsorbent is dumped into landfill 6"'by way of example.

As the statements show, the device according to the invention and the method represent a technically important further development of the state of the art, according to the. inexpensive "disposable" adsorbent and simple process steps, an effective wastewater treatment in particular special highly polluted wastewater such as landfill leachate is possible.

Claims (24)

1. A device for the purification of wastewater, characterized by a container in which above the container bottom is a water-permeable screen and above the sieve adsorbing material is arranged and by at least one drain on the container for the effluent through the sieve water. 2. Apparatus according to claim!, Characterized by internals for flow guidance. 3. Device according to claims 1 and 2, characterized in that the internals are for flow control baffles on the inner container walls. 4. Device according to claims 1-3, characterized in that the same is designed as a tronsportierbarer container. 5. Device according to claims 1-4, characterized in that it has at least one gas and / or liquid supply in the lower region. 6. Device according to claims 1-5, characterized in that it has a height-adjustable water-discharging line for adjusting the water level. 7. Device according to claims 1-5, characterized in that it has an overflow in the upper part. 8. A process for the purification of waste water, characterized in that in the device according to claims 1-7, a layer of adsorbent material is introduced, wherein the adsorbent material is pretreated by introducing hot gas and / or liquid before or after the introduction and in the case of heating with gas then submerged in water and / or a water / steam mixture, that the wastewater to be purified is passed through the layer of adsorbent material and that the treated wastewater flows out of the device. 9. The method according to claim 8, characterized in that the liquid used for the pretreatment is water and / or a water / steam mixture. 10. The method according to claims 8 and 9, characterized in that the absorbent material is coke. 11. The method according to claims 8-10, characterized in that the adsorbent material is blast furnace coke. 12. The method according to claims 8-11, characterized in that the adsorbent material in the pretreatment to 20-200 ⁰ C, preferably 50-18O ⁰ C and particularly preferably to 75-14O ⁰ C is heated. 13. The method according to claims 8-12, characterized in that the pretreatment time 1 minute to 20 hours, preferably 10 minutes to 10 hours, more preferably 10 minutes to 5 hours. 14. The method according to claims 8-13, characterized in that the flow rate of the flowing through the layer of adsorbent material wastewater> 0 to 1 m / h, preferably 0.01 to 0.8 m / h, particularly preferably 0.05 to 0.5 m / h. 15. Process according to claims 8-14, characterized in that the residence time of the waste water is 1 minute to 10 hours, preferably 5 minutes to 7 hours, more preferably 10 minutes to 5 hours. 16. The method according to claims 8-15, characterized in that the wastewater treatment at ^ 0-45 ⁰ C, preferably 5-35 ° C takes place. 17. The method according to claims 8-16, characterized in that the grain size of the adsorbent material from 0.01 to 100mm, preferably 0.05 to 20mm and more preferably 0.05 to 5 mm boträgt. 18. The method according to claims 8-17, characterized in that the grain size corresponds approximately to that of Feinstkoks. 19. The method according to claims 8 and 12-16, characterized in that the soot from oil gasification is used as the adsorbent material. 20. The method according to claims 8-19, characterized in that the same takes place in / at a landfill and landfill leachate is purified. 21. The method according to claims 8-20, characterized in that the adsorbent material is subjected to a pretreatment with hot gas and / or with a liquid. 22. The method according to claims 8-21, characterized in that the pretreatment of the adsorbent material takes place by circulating water over the material. 23. The method according to claims 8-22, characterized in that the pretreatment is carried out with steam and water. 24. Process according to claims 8-23, characterized in that a surface-active agent is added to the pretreatment liquid. For this 17 pages drawings Field of application of the invention The present invention relates to the removal of adsorbable contaminants, in particular organic contaminants, by means of a device in which there is a layer of adsorbent material, which has preferably been pretreated with steam and / or water. Cleaning polluted water to conserve the environment is one of the great challenges facing modern industrial society. There are numerous known methods that work on very different principles.