AU691830B2 - Device for purifying waste water or ground water and use thereof - Google Patents

Abstract

The invention pertains to a device for purifying waste water or groundwater contaminated with biodegradable matter or organic substances that can be removed by adsorption/desorption, characterized by a) a biodegrading fermentation system, b) an absorber system upstream or downstream therefrom, containing a regenerative polymer adsorbent, a feed line and an outlet as well as a steam feed and one drain pipe each for the desorbate and the purified water, and c) a returning line connecting the output of the downstream system to the input of the upstream system.

Description

Gi~-~a~rr~ I DEVICE FOR PURIFYING WASTE WATER OR GROUND WATER, AND ITS USE The invention relates to a device for purifying waste water or ground water, which is contaminated by organic substances that are biodegradable and that can be separated by adsorption desorption, wherein the device is characterised by a fermentation system used for biodegradation and an adsorber system, equipped with a regenerative polymer adsorbent that is equipped with a feed pipe and a discharge pipe for the water (ii) a) with a drainpipe for the desorbate and 1 with a drain pipe for the water, c: haracterised in, Sthat the adsorber system is equipped (iii) with a steam feed; that the water of the discharge pipe of the adsorber system is purified; that the purified water leaves the adsorber system, wherein a) the fermentation system is upstream from the adsoprber system and the desorbate which leaves the adsorber system is recycled by a return pipe to the entrance (feed pipe) of the S. fermentation system or wherein b) the adsorber system is upstream from the fermentation system by a pipe for the desorbate, whereby the microbial fermentation is used for the purification of the desorbate and the fermentation solution is returned by a return pipe to the feed pipe of the waste water or ground water.

L~ s~ Pe ~1~1 ~L~PI The invention further relates to the use of the device for purifying waste water or ground water.

It is known that with the aid of microbiological processes, high rates of degradation of biodegradable compounds in contaminated ground water or waste water can be achieved but that the degradation in this process is generally not complete, so that the guideline values specified by the law for surface waters are not reached. The use of the adsorptive process results in observing the prescribed guideline values, but requires a very expensive process for disposal of the desorbate that accumulates.

It has now been found that by combining the two processes, their advantages can be used in an ideal way and their disadvantages can be eliminated.

o 4 o a s~ll~- I l~ bl k~-SIIPl~gl Based on diagrammatic Figures 1 and 2, the possibilities of these combinations can be explained in more detail: Figure 1 shows a device for purifying waste water or ground water, which is characterized by an upstream fermentation system, a downstream adsorber system, and a return pipe, which causes the desorbate coming out to the input of the fermentation system to be recycled.

In this embodiment, the ground water or waste water is thus first fed for microbiodegradation of the contaminants and then is fed to the absorber system, which almost completely removes the residues of organic substances that are contained in the water.

The desorbate that accumulates is then recycled to the ground water stream of microbiology.

Figure 2 shows a device for purifying waste water or ground water, which is characterized by an upstream adsorber system, a downstream fermentation system and a return pipe, which causes the fermentation solution coming out to be recycled to the discharge point of the waste water or ground water. In this embodiment, the ground water is fed directly to the adsorber system, and microbiological fermentation is used only to treat the desorbate.

In practice, it is generally most advantageous to feed a portion of waste water or ground water to the fermentation system and the remainder to the adsorber system and in this way to adjust the reaction parameters so that the treatment of the waste water or ground water requires as little steam as possible.

3 For the device according to the invention, basically all fermentation systems are suitable that can be used for treating waste water or ground water Atkinson Biochemical Reactors, Pion Ltd., Lyndon 1974), but fermentation systems that make possible continuous fermentation are to be preferred.

An especially preferred device according to the invention is one whose fermentation system consists of one to three fluidizedbed fermenters, as described in non-prepublished wo 93/22346 These fluidized-bed fermenters are characterized by an inverted cone-shaped fermentation chamber with two feed pipes (2 and 3) that are optionally equipped with control valves (4 and of which one feed pipe is arranged vertically in the cone vertex and the second is arranged non-vertically in the cone vertex at 0.02 to 0.3 times the fermentation chamber height and a sedimentation chamber that is present above fermentation chamber which has one or two drainpipes (7 and 8) that are optionally equipped with control valves (9 and The special design of this fluidized-bed fermenter has the effect that a turbulent flow prevails in its fermentation chamber 0 if the liquid to be fermented is fed simultaneously via vertical and horizontal feed pipes (2 and This flow then

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*0 passes into sedimentation chamber in an almost laminar flow.

If such continuously fed fermenters are inoculated with a microorganism culture, the latter forms pellet-like agglomerates, which are suspended in the fluidized bed of fermentation chamber and sink back into sedimentation chamber after a growth phase because of the turbulent flow. Because of these 311116- SI~conditions, these fluidized-bed fermenters are considerably better suited for continuous fermentation of large amounts of liquid over a long period than the previously-known fluidized-bed fermenters, such as, for example, the device described in European Patent EP-B-0258611. Consequently, these fluidized-bed fermenters are especially suitable for, biological wastewater or ground-water treatment.

The design of these fluidized-bed fermenters is basically determined by the type of microorganism cultures that are to be used in them. If these are microorganism cultures which sediment relatively quickly, such as, for example, microorganism immobilizates, as described in International Patent Application WO 88/08825, or fungi cultures, a fluidized-bed fermenter with a fermentation chamber and sedimentation chamber of a relatively low height is preferably used. In the case of relatively poorly sedimenting microorganism cultures, as bacteria cultures generally are, a fluidized-bed fermenter with a relatively tall fermentation chamber and sedimentation chamber is preferred. It is not necessary, however, that a specially configured fermenter be used for each microorganism culture used; by properly regulating the rates of intake of the liquids to be fermented through vertical and nonvertical feed pipes (2 and continuous fermentation can generally also be achieved with fluidized-bed fermenters according to the invention that are not optimally configured for the special case.

Generally, these fluidized-bed fermenters are to be configured in such a way that the upper diameter of fermentation I a a i P~ L chamber is 0.1 to 0.8 times its height. In the case of these numerical values, it is not taken into consideration that the fermentation chamber normally has a truncated cone vertex, which is suitable simply because the fermenters can be cleaned more easily.

It was already mentioned that non-vertically aligned feed pipe is arranged in the shell of the cone at 0.02 to 0.3 times especially 0.05 to 0.15 times the fermentation chamber height, and two feed pipes are aligned in such a way that a fluidized bed is produced when the fermenter is put into operation in the fermentation chamber. Non-vertically-aligned feed pipe can be arranged horizontally in such a way that the horizontal line that points from the intake opening of this feed pipe to the fermentation chamber axis crosses this axis. To create a readily reproducible turbulent flow, it is suitable, however, for the longitudinal axis of the non-vertically-aligned feed pipe and the horizontal lines that point from the intake opening of this feed pipe to the fermentation chamber axis to form an angle vertically and/or horizontally that does not exceed the value 700 in the vertical or a value 600 in the horizontal.

If this feed pipe is arranged pointing vertically upward, the angle is preferably 100 to 600 (especially 300 to 400); if the pipe is vertical, but is arranged pointing downward, the angle suitably has a value of between 100 and 600 (especially 200 to If optionally feed pipe is additionally arranged offset horizontally, the angle is preferably 50 to 600 and especially 200 to 450.

II-~ I I_ I It is obvious to one skilled in the art that the terms "horizontal" and "vertical" are not meant in the mathematical sense, but that the feed pipes can deviate within the usual tolerances from an exact horizontal or vertical arrangement.

Generally, drain pipes (2 and 3) are equipped with conventional control valves (4 and 5) and are connected via a common pipe to a storage vessel that is intended to receive the solution to be fermented.

It was already mentioned that these fluidized-bed fermenters have a sedimentation chamber that is present above fermentation chamber which has one or preferably two drainpipes (7 and 8) that are optionally equipped with control valves (9 and This sedimentation chamber can be configured in such a way that it represents a continuation of the cone-shaped fermentation chamber without transition; in contrast, it can also be configured, for example, in such a way that it consists of one or two cylindrical components that are optionally provided with a conical broadening. In this case, it can be dimensioned in such a way that its upper diameter is 1 to 3 times (especially 1.5 to times) the upper diameter of fermentation chamber Sedimentation chamber is preferably dimensioned in such a way that it has 0.2 to 0.5 times the height of fermentation chamber Sedimentation chamber has one or preferably two drainpipes that are optionally equipped with control valves (9 and 10). Two drainpipes are then suitable if the intention is to recycle a portion of the fermented liquid into the fermentation cycle to dilute the liquid to be fermented until virtually complete conversion of the substrates contained therein can be achieved. In this case, the drainpipe used for recycling is suitably arranged somewhat deeper (preferably 20 to 40% below the upper drainpipe) than the pipe used for drainage.

Just like conventional fermenters, these fluidized-bed fermenters can also be equipped with the conventional auxiliary devices that make possible temperature equalization, pH control, ventilation and/or sterilization of the fermenter content. It can be made of glass and/or noncorroding metal in the same way as conventional fermenters.

Based on the drawings, these fluidized-bed fermenters are to be explained in more detail.

Here: Figure 3 shows a lengthwise section through a fluidized-bed fermenter according to the invention.

Figure 4 shows a cross-section through the fluidized-bed fermenter of Figure 1 at the level of plane A-B.

Figure 5 shows a lengthwise section through a fluidized-bed fermenter with built-in temperature-equalizing, ventilating, and sterilizing devices.

Figure 6 shows a diagrammatic representation of a fermentation unit with a fluidized-bed fermenter according to the invention, and Figure 7 shows a diagrammatic representation of a fermentation unit with two fluidized-bed fermenters that are connected in series.

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I~ I cl-~r M BMPrr. 81 The f luidized-bed f ermenter shown in Figure 3 is intended for treating waste water with bacteria cultures. it consists of cone-shaped fermentation chamber with a trunca~ted cone vertex, sedimentation chamber as well as feed pipes (2 and 3) that are equipped with control valves (4 and 5) and drainpipes (7 and 8) that are equipped with control v ~I and Fermentation chamber has a height of 2.?tIf~o r cnd an upper diameter of 600 mm. Vertical feed pipe and,. at a height of 230 mmn, nonhorizonta. feed pipe which is inclined vertically upward and forms an angle of 350 with it and with the horizontal line, leads into it. Sedimentation chamber is arranged on the upper edge of fermentation chamber This consists of two cylindrical components that are provided with a conical.

*@broadening, is closed above and has an upper diameter of 1300 mm and a total height of 1300 mm. (Hatched area 12 of Figure 3 is intended to symbolize the region in which the bacteria culture is swirled. The chamber identified by number 16 is to symbolize the largely bacteria-free chamber). Below the upper cover, two drainpipes (7 and 8) are dttached facing one another, of which *,..4one pipe which is used for the discharge of the fermentation *..broth, is arranged 250 mm below the upper cover of the sedimentation chamber and pipe which is used for recycling, is arranged Go0 mm below the upper cover of the sedimentation chamber. The fermenter is made of stainless steel. is clear from Fig. 4 that nonvertical feed pipe with the straight line pointing from its intake to the fermentation axis forms an angle a~ of 350" ~l~a~plr ~LL ~IL The fluidized-bed fermenter shown in Figure 5 has the same design as that described in Figure 3, but it also has a circular incoming air pipe (13) just above the bottom that is equipped with nozzles 1, a superheated steam pipe which can be used in it to sterilize the fermenter contents, and a double shell that covers the fermentation chamber for receiving the temperature-equalizing liquid.

The fermentation unit diagrammatically depicted in Figure 6 basically consists of a fluidized-bed fermenter, as e4plained in Figure 3, and a return pipe (17) that is equipped with a metering pump (22) as well as a feed pipe for feeding additive (19) for controlling pH, a feed pipe for feeding H 2 0 z as an oxygen donor a feed pipe for feeding nutrient medium and a feed pipe for feeding waste water which is connected by a branch to feed pipes (2 and 3).

1 m 3 of waste water and of the reflux adjusted to pi 7 and .0.

enriched with nutrient medium are fed hourly by feed pipe (18) to the fermenter that is inoculated with an isolated bacteria-mixed S: culture which is isolated from the corresponding waste water sludge, and control valves (4 and 5) of feed pipes (2 and 3) are S: set in such a way that after the growth phase has ended (about 2 to 6 weeks), a stable fluidized bed with a constant microorganism density results in the fermenter. Then, 1 m 3 of purified waste water is removed hourly from the fermenter via one drainpipe while 7 to 14 m 3 of purified waste water is recycled per hour via the other drainpipe to dilute the waste water or ground water that is fed in.

c, 5%1 IBg#gWIRllsC~WACIIIIil~i~ Finally, the fermentation unit that is diagrammatically depicted in Figure 7 can be mentioned, which is basically distinguished from the device sketched in Figure 6 in that it has two fermentation units (23 and 24), which in principle have the same design as the unit shown in Fig. 6, and drainpipe 32 for removal from unit 24 is used to feed waste water or ground watet to fermentation unit 23. This unit can be adjusted by correspondingly adjusting the control valves so that the fermenters are connected in parallel or in series.

As an adsorber system, the device according to the invention can have a conventional adsorber column that is equipped with a feed pipe and drainpipe for water, a steam feed pipe, and a desorber drainpipe. Each of these pipes ha- a control valve, which makes it possible to switch the column from adsorption to Sdesorption. The column is fed with a regenerative polymer 9 S adsorbent, such as, for example, Wofatit Y 77 (now EP63), Y 59 or EP61 of the Firma Chemie AG [Chemical Company AG], Bitterfeld or XAD2 or XAD4 of the Firma Roehm und Haas [Roehm and Haas Company], in the usual way and is used for adsorption and desorption in a way that is well-known to one skilled in the art (Ullmann's Encyclopedia of Industrial Chemistry 5th Ed. Vol. B3, VCH Verlagsgesellschaft DE Weinheim, Chapter 9, Chem.-Ing.-Techn.

[Chem. Eng. Techn.], MS 1202/84 ref. in Chem.-Ing. Techn. 56, 1984, 242f and Chem. Techn. 43, 1991, 51f).

Such an adsorption system that consists of a single adsorber column has the disadvantage, however, that it cannot operate continuously. Therefore, it is more advantageous, in the device ~BC~ ~s C according to the invention, to use an adsorption system, which consists of 2 to 12 adsorber columns that are connected to one another in such a way that a portion of it is used for adsorbing contaminants in water, while one or optionally also several columns are desorbed by means of steam.

In Figure 8, such an adsorption system is explained in more detail: This system consists of four adsorber columns 41 to 44. It shows a state of the system in which waste water or ground water is introduced into columns 44, 41 and 42 connected in series via the opened control valves of feed pipe 46 and the purified water is discharged via drainpipe 47, collected in reservoir 51, and sent via a pump 50 as coolant into condenser 49 and finally via pipe 52 into the ground water. At the same time, steam is introduced into column 43 via the corresponding control valve from steam pipe 45, and the desorbate is removed via drainpipe 48, completely condensed in condenser 49, and returned via pipe 52 to the fermentation system.

Figure 9 shows a diagrammatic representation of a device according to the invention for purifying waste water or ground water, which basically consists of a fermentation system according to Figure 6 and an adsorber system according to Figure 8.

Claims (4)

1. Device for purifying waste water or ground water, which is contaminated by organic substances that are biodegradable and that can be separated by adsorption desorption, wherein the device is characterised by a fermentation system used for biodegradation and *an adsorber system, equipped with a regenerative polymer adsorbent that is equipped with a feed pipe and a discharge pipe for the water (ii) a) with a drainpipe for the desorbate and B) with a drain pipe for the water, characterised in, that the adsorber system is equipped (iii) with a steam feed; S. that the water of the discharge pipe of the adsorber system is purified; that the purified water leaves the adsorber system, wherein a) the fermentation system is upstream from the adsoprber system and the desorbate which leaves the adsorber system is recycled by a return pipe to the entrance (feed pipe) of the fermentauon system or wherein b) the adsorber system is upstream from the fermentation system by a pipe for the desorbate, wherey the microbial fermentation is used for the purification of the desorbate and the fermentation solution is returned by a return pipe to the feed pipe of the waste water or ground water. I~

2. Device for purifying waste water of ground water according to claim 1, characterised in that the fermentation system consists of one to three fluidized-bed fermenters.

3. Device for purifying waste water of ground water according to claims 1 to 2, characterised in that the adsorber system consists of 1 to 12 adsorber columns that are fed in each case with a regenerative polymer adsorbent.

4. Device for purifying waste water or ground water according to claims 1 to 3, wherein the purified water is used for condensation of the desorbate. Device according to any of the proceeding claims 2 to 4 with reference to 2, wherein the fluidized-bed fermenters are characterised by an inverted cone-shaped fermentation chamber with two feed pipes that are optionally equipped with control valves, of which one feed pipe is arranged vertically in the cone vertex and the second is arranged non vertically in the cone vertex at 0.02 to 0.3 times the fermentation chamber .heights and a sedimentation chamber that is present above fermentation J: chamber, which has one or two drainpipes that are optionally equipped with control valves s* 0 9 oo4r