DE7148354U - DEVICE FOR TREATING WASTE CONTAINING LIQUIDS - Google Patents

Description

Dipl.-Ing. H.Weickmann, Dipi ..- Phys. Dr. K. Finckb D1PL.-ING. F. A-Weickmann, Dipl.-Chem. B. Huber

^DES <MUNICH 86, DEN | £ Jgp

G 71 43 354.0 POST BOX 860320

Research Corporation mdhlstrasse 22. phone number 9.392 «/ 22

Device for the treatment of waste containing

Liquids ρ

The invention relates to an apparatus for treating liquids containing waste, for example raw wastewater or pretreated waste. In particular, the invention relates to a method of venting a liquid containing waste for the purpose of dispersing bacterial cultures in the waste water, while this is kept circulating continuously through a biochemical filter system.

Filter systems for treating liquid waste have been known for many years. However, the obvious have The shortcomings of these systems received more and more attention, especially with regard to the fact that water pollution has reached critical levels everywhere. The ever growing needs an exploding population and the ever decreasing supply of unpolluted water could only partially be made up for by fairly limited improvements to conventional sewage treatment systems.

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The information disclosed in U.S. Patent 3,563,888 dated 02/16/71 proposed solutions have proven to be quite useful. Yet the present invention lies the underlying task is to provide an improvement and further development of the subject matter of the main application. the The invention is based on the new basic ideas of the invention laid down in the main application, but improves this A method in that the flow through and in contact with the submerged filter media from the vertical mode to a horizontal mode, d. H. horizontal flow direction is changed. This horizontal flow mode increases as has been found in practice, the internal sedimentation capacity in the process and thereby makes the treatment of stable and for concentrated industrial waste, sewage and combined sewage and solid waste (Garbage) and also more effective for partially treated waste.

In the horizontal mode of operation according to the invention, the waste is in contact with the crops while it is horizontal moved through the filter media. In this way, in addition to the disposal of waste through impact on the filter medium, the waste also precipitates through sedimentation due to gravity. When treating waste with a high solid content, such as raw wastewater, relatively wide open horizontal channels can be used in the filter media in order to achieve effective separation. An intermediate process could be the horizontal mode of operation of the present invention with stones, for example or other spherical or roughly spherical materials as "filter media use, whereby one the desired high Turbulence for the treatment of pretreated wastewater achieved to a high degree of cleanliness.

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A number of relevant studies have revealed that a critical design factor in the handling of concentrated waste lies in the oxygen transfer. Initially, efforts focused on such situations like mechanical clogging, etc. The need for oxygen becomes more understandable when the facility is considered in three parts: 1) oxygen uptake, 2) oxygen utilization and 3) hydraulic circulation. So far, the third stage has been carried out using the The main application disclosed the oxygen transfer with bubbling air and a calm water surface. In the horizontal operating mode, the circulating liquid moves horizontally along the surface above and out of contact with the filter media. This makes the oxygen transfer due to the longer Time during which the interface is exposed and improved due to the turbulence. For heaped rubbish, this is however only incidental and it has been found necessary to reduce the oxygen transfer by increasing the turbulence (Loss of gradient) in the return line, i.e. the channel above the filter media. When too strong If there is a loss of gradient, the ascent of the air slows down. In order to improve the turbulence, in the return duct at the top of each cell a number of baffles were installed around the end and this resulted in a satisfactory result Results.

The new submerged filter method of the present invention combines elements like the procedure according to the main application different processes - activated bacterial cultures, a large surface area and filtration, which in the extended Sense is a form of sedimentation. The biological submerged filter has in one embodiment of the invention a cell in which filter media are arranged so that

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a horizontal flow path for the liquid is created, which is connected to an air lift pump and a liquid inlet and outlet -Deduction is related. The cell is filled with waste to a suitable height above the filter and the air lift pump is started. The waste begins rapidly in a horizontal direction through the filter to circulate to the airlift pump, from where it is ejected again, to over the top of the filter media flow back and then flow down and back horizontally through the filter media and so on. During the Return line, some liquid is drained from the cell and flows into another same cell for further treatment there to become.

As the waste circulates, particles are removed by the filter, with the larger particles moving through settle their own weight on the bottom of the filter media, while a dense, flocculent, aerobic bacterial culture builds up throughout the filter developed. The submerged culture is porous and has a flocculating effect; she is not liable as one thick layer of slime on the filter media, as is the case in the conventional trickle filter.

In one embodiment of the invention there are two or more cells containing such submerged filters are connected in series, so that each cell relates to the cells in the preceding cell Unit remaining. Adjusts waste concentration and carries out another metabolism. The size of the fiI-termeddlum or the channel through the filter can be larger or coarser in the first cell and in each subsequent cell Cell finer downstream, as described in the main patent.

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To continue the description of the exemplary embodiment commenced above: The air lift pump drives the waste quickly through the system. In each cycle, 1) the waste is exposed to the active bacterial cultures, 2) the water is re-aerated and the dissolved oxygen is rapidly transferred to the bacterial cultures, and 3) gaseous metabolic end products such as CO 2 are vented to the environment. In the course of the treatment, the waste is expediently circulated many times (for example a few hundred times) and a high ratio of circulation to throughput is preferably provided in the cell, as is also disclosed in the main patent. The ümlaufverhältnis is equal to the fluid or volume of water ¹ * which is circulated by the airlift effect in the time unit in the boiler, divided by the liquid or amount of water that goes through the treatment process per unit of time, ie, runs entirely through the boiler. This ratio can vary from around 200 to around 1000. This gives a large supply of oxygen, ventilates the medium and gives the organisms many opportunities to convert the contaminants.

The number of cells in the treatment can depend on the degree of contamination of the inflow (i.e. the incoming waste liquid) and the desired degree of filtration of the drain can be varied. Although most of the impurities removes insecticides, detergents, antibiotics and similar organic molecules in the ventilated filters, however, an activated carbon unit or a filter tank with vertical flow, as described in the patent, can also be used of the main patent is described, applied in a downstream process as a special purification stage so that such contaminants are more completely removed and also odor and color are eliminated.

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Further details and advantages of the invention emerge from the following description of an exemplary embodiment based on the attached drawings. Show it:

1 shows a schematic view of a filter system according to the invention in one embodiment,

2 shows a vertical section through a submerged filter according to the invention, the filter media being schematic are shown;

Fig. 3 is a horizontal section along the line 3-3 of FIG.

Fig. 1 shows schematically two tanks A and B which are connected in series. Filter media F are provided in the tanks, which are traversed in the horizontal direction.

Tanks A and B are constructed alike and can be of any suitable shape. In the method according to the invention, biochemical reactions take place in these tanks. For this purpose, an active bacterial culture is suspended in the pores of the filter medium. The filter medium consists of stones, river sand or sand, or of parallel, spaced, horizontal plates or parallel, spaced horizontal arches of a thermoplastic material, corrugated fiberglass or other suitable material. The waste is aerobically converted in the containers and the system is also designed in such a way that the gases developed during metabolism, for example carbon dioxide (CO ₂ ), are effectively vented to the outside. If nitrogen is present in the impurities, this is oxidized under the prevailing aerobic conditions to nitrate, which is soluble.

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• *

The specific size and classification of the filter media in The containers can be varied depending on the requirements of the particular system and the filter media can be made from Gradually become finer tank to tank, as described in more detail in the main patent.

The number of filtration stages in the system according to the invention can depend on the degree of contamination of the inflow and the desired composition of the effluent can be changed. For example, tanks A and B can be used to either treating raw sewage directly or using the effluent from a conventional trickle filter system to treat and process activated sludge (not shown). In the former case, more than two tanks can be used A, B can be connected in series.

As shown in FIGS. 1 and 2, the two tanks A and B are constructed similarly or identically and have an inlet 20, an outlet 22, filter media F, an air lift pump 24 and a return duct 26 above the filter media F. An inlet chamber 30 is formed in the tank at one end of the filter media F and an outlet chamber at the other end 32. In a tubular passage 34 which opens at its upper end into the return channel 26 and to the outlet 22 is open, an air lifting device is provided. If the tanks are connected in series, there is a line 36 is provided which connects the outlet of one tank to the inlet of the next tank downstream.

The tank A in the example of FIGS. 2 and 3 is rectangular in vertical and horizontal section and longer than it is high.

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For more concentrated wastewater, a larger length: height ratio is useful in order to increase the surface length of the return channel 26 and thus to lengthen the aeration time in the filter media F and to shorten the oxygen transition time. The gaseous metabolic end products, such as CO ₂ , are released from the surface of the liquid flowing through the return channel 26 and discharged into the ambient air.

In the embodiment of FIGS. 2 and 3, the filter media F several vertically and horizontally spaced plates 40, with passages through the horizontal distance 42, see Figure 3. A continuous plate 44 covers the top of the filter media. By doing Return channel 26, a plurality of guide plates 46 are arranged in the manner shown. These guide plates support the turbulence, which in some systems is considered important to the oxygen transfer during the flow through the return channel 26 to improve. The return channel is stepped, as shown in Fig. 2, or has a decreasing cross section in the direction from right to left of this figure. Above it is offered to the environment.

The plates 40 can be made of any suitable material; they can be vertically spaced, horizontal Arch-shaped parts made from a thermoplastic material be, which are mounted horizontally to the direction of flow of the liquid in such a way that they have the largest possible surface perform. In the example shown, the air lifting device has a compressor or a pump 48 and an outlet conduit 50, 52, the conduit piece 52 extending concentrically in the tubular passage 34 and terminates in an outlet located above the bottom 54 of tank A. The passage 34 may be on the floor 54 sit on, as shown in Fig. 2, and with openings 56 for

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the entry of the liquid must be provided. Below passage 34 is a normally closed drain valve arranged. The upper end of the passage 34 is connected to the plate 44 and is open to the return channel 26 and to the outlet 22.

Air or another suitable oxygen-containing gas is passed through the line 50, 52 is pumped in and bubbles in bubbles in the passage 34 in the space between the line piece 52 and the Wall of the passage 34 upwards, creating an airlift effect, as described in the main patent. As desired A heating device, for example a heating coil 60 indicated schematically in FIG Line 50, 52 to preheat flowing gas.

Instead of the plates 40 shown in FIGS. 2 and 3, stones or other spherical or something like filter media can also be used as filter media spherical materials are used. Several tanks A, for example two or three, can be arranged in series are, in such a way that in each tank there is a horizontal flow through the filter media, or that a Combination of cascaded cells with a submerged filter of vertical flow mode according to the Main patent at the end of the series is used. Of course, different submerged filter units can of the described Type can be connected in parallel or in a group or in series. If desired, sewage can also be returned to further upstream units may be provided. Such modifications obvious to the person skilled in the art are within the scope of Invention included.

In the tanks according to the invention with a horizontal flow mode, the waste-containing liquid to be treated is in the first Tank introduced through inlet 20. There is sufficient sewage

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11 "J ·· · ·

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The amount of water initiated so that the filter F is completely submerged is. The pump 48 pumps the oxygen-containing gas into the passage 34, whereby the liquid is drawn horizontally through the filter F and then driven upwards through the passage 34, whereupon part of the liquid is returned through the return channel 26 to flow again through the filter F while another part of the liquid is discharged through the outlet 22. In the tank there is a constant circulation and circulation instead of.

The column of oxygen-containing gas emerging from the outlet of the pipe section 52 leaks, not only takes the waste liquid " up with. First, it increases at a rate that ensures rapid circulation and thus a high rate of conversion. Second, permeates during of the lifting of the waste liquid in the passage 34, the oxygen contained in the air is entrained in the column of air Waste liquid. In this way a sufficient amount of oxygen is passed on to the waste to prevent the aerobic process To stimulate or strengthen the metabolism again and again. Oxygen is rapidly consumed during aerobic metabolism. Dahei Oxygen must be constantly replenished so that the waste can be effectively converted.

As in the case of the submerged vertical flow mode filter according to the parent patent, it is essential that a large circulation: throughput ratio of the liquid be achieved in the submerged biological process of the present invention. This ratio is defined as the quotient of the amount of liquid that circulates through the passage 34 with fluid lift in the unit of time and the amount of liquid that passes through the treatment process in the unit of time (exits through the outlet 22). This quotient can be varied, for example, by changing the inflow velocity of the liquid into the container. To give an example, the quotient is between about 200 and 1000 : 1. This means a considerable improvement over conventional

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chen systems in which the ratio is in the range between 1 and 5: 1.

Because the filter media is completely submerged and therefore not immediately exposed to the atmosphere, the bacterial culture is highly porous and flaky and the circulation becomes not delayed like this in a trickle filter system Case is. In the plant shown in Fig. 1, since the waste conversion in the first tank A is high, only much smaller ones remain Waste amounts are left over and there is less bacterial production in the downstream tanks, which is why in these Downstream tanks finer filter media can be used. This will change the design of the system and improves the filtering properties because the waste is exposed to more bacteria than in a smaller space this is possible in conventional systems. The circulation: throughput ratio can therefore be in the downstream tank or the downstream tanks be smaller and this is sufficient insofar as the liquid in the tank A for the first time has been treated before it enters tank B.

Further, since the waste in contact with the bacterial culture moves horizontally through the fi ¹ termedien F of each tank, waste is discharged by sedimentation due to gravity, and this sedimentation occurs advantageously in addition to the waste disposal by impact with the filter medium.

As shown in FIGS. 2 and 3, the guide plates 46 improve the oxygen transfer even further, due to the Time the interface is exposed to oxygen and turbulence. With the increase in turbulence, generated from the guide plates 46, there was also a simultaneous increase in the hydraulic gradient loss 47 in a test facility observed in the return channel 26. In

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This hydraulic gradient loss is greatly exaggerated in FIG. 2 indicated. Namely, if there is excessive hydraulic head loss, the airlift pump performance will decrease away. Hydraulic head loss on the order of about 25 mm (1 inch) has been found to be acceptable proven. For some purposes, the turbulence increase is not necessary due to the guide plates 46, which is why the guide plates can be omitted in such a case.

In that the filter is completely below the surface of the Waste liquid is submerged as well as through a suitable By attaching the air lift tube, it is possible to maintain continuous circulation in the system. Since the upper end of the passage 34 always remains below the level of the liquid, it is not necessary to have the liquid to raise above the liquid level. Therefore, the energy requirement for the circulation is advantageously low.

As mentioned, the present invention can be applied either to the effluent from a conventional system still to be treated, or to treat concentrated waste liquids or the raw sewage as such to treat.

Example I.

A field test facility was installed, the three tanks according to the invention connected in series and with horizontal Flow through each tank. The effluent from a packing plant was treated. The results after operating the facility for four months, far exceeded expectations and prove the suitability of the

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finding for the treatment of concentrated waste. The following is a summary of the results for the four month period set up:

Volume of waste treated per day: 566 dm / day

(150 gallons)

Retention time: 48 hours

Number of analytical observations

incoming waste 16

outflowing waste 10

BOD (5 days, 20 ⁰ C)

incoming waste

on average 1424 mg O ₂ / liter

Fluctuation range 607 - 4126

outflowing waste

on average 138 mg O ₂ / liter

Fluctuation range 97 - 162

% Reduction 90.3%

In comparison with a conventional active sludge system, the present device finished with about three times the organic charge. The charge intensities are used for comparison of the two systems, with the number of grams per cubic decimeter and day being given. This is considered realistic Measure viewed.

System charge intensity

(Grams of BSB / dnv *. Day)

1. Activated sludge a) Aerator alone 0.43

b) aerator + second

Settling basin 0.30

2. Submerged filter according to

Invention 0.72

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If digesters, thickeners, etc. are still included in the activated sludge system, the charge intensity is reduced further.

Example II

In a second test facility two tanks were connected in series with an inventive horizontal flow mode to ⁰ treat treated in the third stage a in a conventional manner (active sludge), waste water with a 2O 5-day C-BOD of approximately 23 mg 0, / liter. The table below, for which the measurements were taken over a period of four months, shows the operation and the results:

Run crowd
m / day Withholding
time / hours Cloudiness
ppm Outflow BOD
5 days 20 ⁰ C
(mg O ₂ / liter) 1 2.54 8.2 1.3 5.38 2 - - - 2.95 3 3.32 6.1 3.2 5.92 4th 3.90 5.2 2.7 - 5 3.59 5.65 2.2 2.87 6th 2.55 7.95 2.0 2.66 7th 2.55 7.95 3.15 12.1 8th 2.55 7.95 2.0 4.1 9 2.46 8.23 2.45 4.56 10 - 7.95 3.55 2.07 medium 2.94 7.24 2.51 4.73

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Example III

An arrangement of three successively connected, horizontal flow filters according to the invention, as described in Example I, was observed for a period of 7 months. Each device contained plastic bodies made from semi-cylindrical plates 15.2 cm wide and 14 cm long. The plates were packed in the tank at a density of 44 plates per cubic foot (approximately 1.5 plates per dm ³ ) so that an equivalent horizontal surface area of 10 square feet per cubic foot of the filter media would be required.

came up (336 cm per cubic decimeter). A sum of the results from the measurement of the BOD reduction is shown below specified:

BOD (mg / 1.5 days, 20 ⁰ C)

Run influx 1. unit 2nd unit 3rd unit
(From stream) 1 662 _— —— - 2 2015 - - - 3 988 - - 163 4th 674 - - 162 5 638 - - 152 6th 910 - - 129 7th 1133 - - 97 8th 1066 - - 132 9 2188 - - 154 10 1178 775 324 - 11th 1416 535 221 142 12th 1268 443 251 146 13th - 255 190 180 14th 958 161 - 55 15th 1607 369 110 69 16 1280 - 90 53 17th 723 243 52 medium 1260 480 266 120
187 all
Data

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Continued table

Inflow 1st unit 2nd unit 3rd unit

(Outflow)

% Reduction 0 62 79 90.5

85

As is apparent from the above description, the present invention retains the essential characteristics and merits the filtering process described in the main patent and the corresponding device and grants additional Advantages as outlined above.

The size of the filter media used can be changed as desired and it is not essential to the invention that they is graduated from one tank to the next. If you want, you can use the same river sand as filter medium for all tanks use. The particle size of the river sand is chosen so that there are noticeable passages between the particles Dimensions arise. Experience has shown that the smallest stone size for the final treatment of water is about Should be 19 mm (0.75 in) for large horizontal facilities. Mixed filter media should not be used in the The same unit can be used, except when a series of units is provided, in which each unit is a medium of the same or smaller dimensions as the preceding unit. It was also found to be finer Sand gives excellent chemical results but is not practical due to its inadequate ability to To create gaps.

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Possibly one can provide coarser or larger particles in the tank for the lower part of the filtering medium F and finer particles above. This would help reduce hydraulic drag and break the ground to keep shivered.

Changes to the system described and shown are possible within the scope of the invention.

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Claims (13)

Protection claims 1. Device for treating liquids containing waste, in which the liquid containing waste is introduced into a tank which has a filter medium and a separate one contains free passage in connection with this medium, in which further an oxygen-containing gas in the passage is introduced such that it creates a pumping action in this passage and gas and liquid together in flow in the same direction through the passage, and in which the liquid is continuous in the tank and through the Passage is brought into circulation by means of the pumping action and part of the circulating liquid is continuously discharged is withdrawn from the tank, characterized by a tank (A) with an inlet (20) for introducing the waste-containing liquid, with an outlet (22) for discharging part of the circulating liquid and with a filter medium (F), furthermore through an open passage (34) next to the filter medium with inlet openings (56) and outlet openings that are spaced apart therefrom in the tank, by pumping means (48-52) in communication with the passage and a flow oxygen-containing gas sends through the passage, such an arrangement is made that in the tank a Flow path for the continuous circulation and circulation of the liquid in a horizontal direction the filter media is created and then in a single direction through the passage and the outlet communicates with that flow path. 2. Apparatus according to claim 1, characterized in that 7148354 07/06/78 ι? η · ;; the passage (34) is dimensioned so that through it per unit of time about 200 to 1000 times that of the The amount of liquid withdrawn from the tank per unit of time is flowing. 3. Apparatus according to claim 1, characterized in that the tank above the outlet opening of the passage (34) is open to the environment. 4. Device according to one of claims 1 to 3, characterized characterized in that the outlet (22) is in the vicinity of the outlet opening of the passage (34) is arranged. 5. Device according to one of the preceding claims, characterized in that part of the passage (3 4) is arranged vertically and next to the filter medium and that the inlet openings (56) next to the bottom (54) of the tank and the outlet openings are closest to the upper end of the filter medium, and that another part (26) of the passage is arranged horizontally above the filter medium. 6. Device according to one of claims 1 to 5, characterized by a second tank (B), the inlet of which with the outlet (22) of the first tank (A) is connected so that the liquid withdrawn from the first tank is introduced into the second tank is and in the same way as the first tank (A) with a filter medium and a pump device and a Outlet is provided. 7. Apparatus according to claim 6, characterized in that the filter media are particulate in both tanks and the Particles in the first tank are coarser than in the second tank and that the ratio of the 7148354 07/06/78 menden amount of liquid to the amount of liquid withdrawn from the boiler the first tank is larger than the second tank. 8. Apparatus according to claim 6, characterized in that the flow path of the second vessel also provides a horizontal flow through the filter medium. 9. Device according to one of claims 1 to 8, characterized by guide members (46) which are arranged in the passage (26) separately from the pumping action and in the circulating fluid create turbulence. 10. The device according to claim 1 or one of the following claims, characterized in that at least a part (26) of the passage is arranged horizontally. 11. The device according to claim 10, characterized in that that the horizontal part (26) of the passage is arranged above the filter medium. 12. The device according to claim 11, characterized in that the turbulence-generating device parts (46) in are arranged on the horizontal part of the passage. 13. The device according to claim 12, characterized in that that the turbulence-generating device parts consist of several guide plates (46), which are in the horizontal part (26) of the passage are arranged and spaced from each other in the direction of flow through this horizontal part. 7148354 07/06/78