EP1855775A1

EP1855775A1 - Method and device for the purification of rain drainage water

Info

Publication number: EP1855775A1
Application number: EP06705379A
Authority: EP
Inventors: Giorgio Morandini; Martin Armbruster
Original assignee: OEKAG WasserTechnik Schweiz AG
Current assignee: OEKAG WasserTechnik Schweiz AG
Priority date: 2005-03-05
Filing date: 2006-03-03
Publication date: 2007-11-21
Also published as: WO2006094422A1

Abstract

The invention relates to a method for purification of rain drainage water, in particular, the run-off from roads, whereby the volumetric flow of the rainwater, during adequate precipitation, is divided into an early flow first partial stream and a subsequent partial stream, whereby the predominant portion of the first stream of rain drainage water is run into at least one collector chamber, with a good hydraulic separation from the subsequent partial flow, both partial flows are introduced into a purification and at least the partial collected flow is separated from contaminants in a purification method of greater separative capacity than a purely gravitational separation.

Description

Method and device for cleaning rainwater

The invention relates to a method for cleaning rainwater, in particular street sewage, according to the preamble of patent claim 1 further relates to an apparatus for performing the method according to claim 1.

Such a method and associated devices are known, for example, from EP 1 108 455 A1. Also EP 1 129 756 A2 discloses such technique. Finally, similar methods are used in road sewer systems, where in particular during heavy rainfall partial flows, for example, in rainwater retention basins in shunt or in the main circuit, in catch basin, rain overflow basin or z. B. are retained in duct storage spaces. It is known that rainwater is very pure in itself

Water is and only by the removal of deposited on the overflowed by the rain surface dirt is more or less heavily polluted wastewater. It is also known that rainwater effluents flush off the substantial proportion of contaminant load, at least in the event of heavy rainfall events, with the first flushing surge from the area overflowed subsequent rainwater flow thus flows over rinsed areas and consequently remains largely clean. Unfavorable topologies of the overflow area, such. B. terrain with very low gradient and / or very long flow paths and long-lasting rain events low intensity can ensure that this effect of the separability of the rainwater in a temporally first partial flow with high pollution load and a temporally following partial flow low pollution decreases insofar as the separation of volumetric flow with and without contaminant load expands in time and blurred. Thus, the temporally following partial flow can still have a significant proportion of contaminated cargo. It is also known that processes of increased cleaning performance, ie those processes which are more efficient than pure gravitative separation processes in principle free flow through the

Cleaning volumes are then limited in their performance, when they are exposed to a combination of high hydraulic load and at the same time high pollution load. There are various methods of increased cleaning performance, z. B. filtration method of different power classes or z. B. also coalescing. A method compared to pure gravitational separation in principle free flow increased cleaning power but also results already by a gravitational separation with heavy throttling the process, since in this case dirt trays more time for sedimentation resp. Flotation is given. If you now separate the flushing surge, which regularly has the unfavorable combination of high hydraulic load and high contaminant load, you can perform this under heavily throttled drain cleaning, which is more powerful than pure gravitative separation processes in the free flow. Different techniques for the purification of rain waste water make use of the state of the rinsing surge, but assume that the volume flow following the rinsing surge can be discarded without being cleaned up. Other techniques also want to take advantage of the state of the flushing surge, but do not separate, for example, into a temporally first and a temporally second partial volume flow, but into a volume flow that falls below a limit value of the volume flow and a second part that exceeds the limit value. As flushing the first mentioned volume flow is therefore considered. The part of increased volumetric flow is therefore considered to be the clean part as it has a greater dilution of the contaminant load. This method has the disadvantage that the second partial flow is separated at a time from the first, regarded as flushing stream, to which the entire volume flow transported in any case still dirt load. Thus, such methods are ^'not the Spülstoßprinzip substantially fair, in which a process is not upstream, which separates the temporally first volume flow hydraulically efficient from the temporally following stream, ie the two streams hydraulically strongly separates resp. decoupled. Such a strong hydraulic separation can z. B. via an automatic or via a controlled or regulated hydraulic switch. A strong hydraulic separation is therefore synonymous with the fact that the rinse can be directed into at least its own volume, which is essentially no volume exchange with the subsequent volume flow after its filling, so at least not the majority of the following volume flow into this volume and flow displace the rinsing volume or can release already trapped volume and trapped particles. Still other methods want to make use of the state of the flushing surge, but do not separate the partial flows at all, but lead you in time through several treatment volumes. At least the first treatment volume should make up the flushing swelling treatment, followed by further treatment volumes which, in theory, are responsible for the cleaning of the then less loaded volume flow. At high hydraulic loads, however, the cleaning processes in the volumes flowing through in the following can nevertheless be exposed to considerable contaminant loads, which then no longer exist in the previous tanks can be restrained. These method approaches also lack the strong hydraulic separation of the first flush with high pollution load from the subsequent flow with less Schmutzfrächt.

For the reasons mentioned above, it is important to clean both partial flows.

The technique of EP 1 108 455 Al takes advantage of the facts of the rinsing surge, stores the temporally first partial flow of the soiled rinsing surge and allows the temporally following partial flow to pass. Since the later part stream is not subjected to purification, this method and associated technique then ^' significant drawbacks when z. B. unfavorable topologies or long-lasting rain events low intensity ensure that even later in time incurred partial flows transport pollution. This pollution is passed through this technology in the sequence untreated into nature. A measure for the strong hydraulic separation of trapped volume and subsequent flow is not given in this technique. With full filling of the collecting volume and overflow of the separation space, the subsequent volume flow can easily mix with the trapped volume and thus mobilize large portions of already collected pollution load again and carry away. Although the technique according to EP 1 129 756 A2 cleans the entire volume flow, provided that the intensity of the rain event does not exceed the hydraulic performance of the technology. Since, however, all partial flows flow through one and the same retention volume, the heavily loaded first partial flow and the temporally following, much cleaner partial flow mix. A temporal reversal of AnfalIsZeitpunkt and time of cleaning the partial volume flows is not given here, because the subsequent flow displaces the rinsing surge from the catchment volume and promotes him with its high pollution load time first in the treatment. This technique is based on a method which is a combination of the above-mentioned methods, all of which have disadvantages. Other known techniques, such. As the rainwater retention basin, share volume flows not according to temporal criteria of the outflow, but according to its intensity. If the intensity of the first flushing surge is less than the design intensity for the operating case of such restraint technology, the flushing surge is not retained in this technique and, together with its high contaminant load, completely flows past the retention volume. And even if the first partial flow is generated with high intensity, at most the part is retained which exceeds the design intensity. Very often, the process of gravitational separation, ie separation of heavy matter by sedimentation and separation of light matter by abrasion, is used for the treatment of road wastewater. In order to achieve high cleaning efficiency at high flow rates, such processes required enormously large retention volumes, which in practice can not be realized for cost reasons. As a result, the efficiency in the retention of the relevant contaminants for regularly much too small to be realized systems with gravitational separation is known to be very poor and meets in any way more today's requirements. More and more frequently, therefore, methods of higher cleaning performance, eg. B. screening or filtration required. Unlike gravity methods have

Piltration method but not only the hydraulic load as a limiting factor; In addition, they are still and in particular very sensitive to high pollutant load per time. In addition, filters are barriers and form a barrier that can not be flushed. The combination of high hydraulic loads with simultaneously high pollution load, which is present at the arrival of the rinse surge at the cleaning, can be treated only with considerable effort. If processes of higher cleaning power are used, they must therefore often be coupled with expensive pretreatment processes in order to achieve the Reduce contamination before the actual cleaning process.

The present invention is based on the object to overcome the various disadvantages of prior art and to allow a simplified way the treatment of the entire rainwater seizure with a more efficient and safe compared to gravitational separation process. This object is achieved by a method according to the features of patent claim 1.

According to the invention, at least the major part of the highly contaminated with dirt load temporally first partial flow of each rainfall is collected and cached and the temporally following partial flow hydraulically disconnected from the previous partial flow so that it can not be significantly mixed with the early partial flow. The temporal rinsing surge subsequent partial flow is thus supplied in time before the rinsing surge of further purification, treated both streams with a more powerful method than the gravitational separation and finally the rinsing can be treated greatly throttled time after him in the supply still temporally following partial flow. The treatment of flushing may also already during the onset seizure of the following

Volumetric flow, if it is sufficiently throttled. In this case, without disadvantages for the Process also a part of the subsequent volume flow additionally flow into the collection volume. In the case of a very long rain event, the time reversal can even be lost in individual cases, despite the great throttling, without this leading to a disadvantage for the process.

With this method, the temporal sequence of the treatment of rinsing surge with high pollution load and possibly high volumetric flow rate and subsequent flow, possibly also with high volumetric flow, but with significantly reduced pollution load, exchanged, the two streams do not mix substantially and thus each can be fed separately to a treatment which is superior to the gravitational separation. Since the treatment of the SpülSchwallvolumens can be done very strong throttled after draining any rain donations high hydraulic intensity with this method, the highly limiting case of simultaneous loading of the treatment process with high hydraulic load and high pollution load burden can be easily avoided. Only in the event that the treatment facilities laid out in accordance with the design were hydraulically overloaded in the case of an exceptional rain event, must a part of the after-flow, slightly soiled one have to be relieved

Volume flow untreated past the plant. Even in case of overload, the rinsing with its higher Schmutzfrächt completely and the essential parts of the following volume flow of cleaning supplied. On the other hand, if the rain dispenser is smaller than the collection volume for the rinsing swirl, separation does not take place, but the entire rain dispenser is taken up by the collecting volume and then treated with a high degree of delay. A separation into a time flowing in formerly flowing first partial flow and a temporally following partial flow is thus only in the case of sufficiently large rainfall. This division advantageously makes it possible to purify the flush more intensively than the remaining rainwater. The necessary for avoiding mixing hydraulic decoupling of the two streams can be achieved by technical devices such. B. Check valves or check valves. But even by simple means without moving parts, which bring a mixing high in a direction of high hydraulic resistance, the decoupling can be done. Technology without moving parts is very resistant to interference and low maintenance and thus z. As for StraßenabwasSerbehandlungen in remote areas particularly advantageous. One-sided high hydraulic resistance without moving parts can be z. B. achieve by filling the storage volume for the

Flushing over a partially filled pipe takes place, the more with increasing filling of the storage volume is filled and filled with full storage volume itself. Due to the significantly larger wetted area, the hydraulic resistance increases strongly, a strong exchange flow through this pipe can not take place. And Z. B. also suitably shaped diaphragms and nozzles can be used for strong hydraulic decoupling without moving parts. Collecting volumes can be carried out in the event of favorable pressure-height ratios being self-draining or, under unfavorable pressure-height conditions, automatically drained via pumps. Manual or semi-automatic interventions for emptying are therefore not necessary. An advantageous solution of the inventive task further results when the method is realized so that at the inlet of a collecting container a

Separating device is arranged as a chamber with at least one inlet and at least two processes. If the drains of the separation chamber are arranged at a sufficient distance one above the other, at first only the lower drain is flowed through, the upper drain remains initially dry. The lower drain opens into a drain pipe and this in the catchment volume for the time flowing earlier partial flow. First, the drainpipe is filled partially filled and stored the entire rinse in the collection volume. With increasing filling of the collecting volume, water in the drainage tube will back up. Achieve this Backflow the separator and the water level in it rises above the Sohlenkote the upper drain, the phase of catching the rinse is completed. This is now, only by the fully filled tube with high flow resistance connected to the separator, hydraulically strongly decoupled in its catchment volume. The temporally following partial flow with significantly lower contaminant load then flows through the upper outlet from the separator out before the caching rinse surge treatment, which can be charged due to the smaller pollution load with a much higher hydraulic load. Only when the rainfall is finished, the catchment volume emptied at significantly throttled drain via the same cleaning device or an additional cleaning device.

A particularly advantageous solution results when the purification of the first partial flow is combined with high purification performance, for example with coalescence technology and / or adsorption technology and / or with materials which can absorb light substances and, if appropriate, biodegrade by means of suitable microorganisms. Lightweight materials can be retained with suitable separation devices, eg immersion walls. Existing devices for collecting rainwater waste or existing gravity separation basins can be retrofitted with components advantageous to the solve the task according to the invention. Savable space can be used for further cleaning devices. It is advantageous to provide a collecting container for incidents in dry weather. Advantageously and inexpensively, the catch basin can be designed as a sealed ground basin. The invention is independent of the form in which necessary structures are implemented, so whether round, polygonal or in any other form and in what execution, whether z. B. with collection volumes in steel, concrete, earth or any other construction. The invention is further independent of whether necessary structures are carried out with one or more contiguous or separate collection volumes or cleaning devices. The invention is independent of whether the separation of the volumetric flows is carried out directly in front of the place or places where the cleaning process is carried out, or decentralized at one or more places at some distance. The invention is independent of whether the associated technique is realized with rigid components or whether individual parts are movable and / or flexible and / or whether individual components are at least temporarily partially or completely disassembled. The invention will be described in more detail with reference to FIGS. 1 to 17. Fig. 1 shows a possible embodiment of the invention in cross section and Fig. Ia is a plan view, Fig. 2 shows the time sequence of the cleaning process. The device (Fig.l) is divided by three concentric annular walls 1, 2 and 3 into the chambers A, B and C. Through the line 4, the rain waste water in the chamber A flows to the device. Via two nozzle-shaped slots 5a and 5b, first of all the flushing surge arrives from chamber A into chamber B (ti in FIG. 2). The water level 11 in chamber A is slightly higher than the water level 12 in chamber B (ti, Fig. 2). In chamber B is the cleaning device 6 for the rinsing surge, which drains over the very much throttled drain line 7. If the water level 11 in chamber A exceeds the upper edge of the dividing wall 3, the inflowing water no longer flows into chamber B, but flows over the wall 3 and flows into chamber C (t ₂ in FIG. 2). The nozzle-shaped slots 5a and 5b have in the direction of flow from chamber A to chamber B a much higher flow resistance than in the opposite direction, the rinsing surge is thus trapped in chamber B and hydraulically very strongly separated from the subsequent partial flow to the chamber A. Rinsing the Spülschwoll from chamber B in chamber C is the subsequent partial flow is not possible. The throttling of the drain 7 may be set so that the evacuation of chamber B will last many hours to several days. Chamber C empties unthrottled via cleaning device 8 and line 9, so that in the inventive cleaning process, the time sequence of the partial volume flows in the process is reversed. Chamber C, flows through during the rain event from the time later inflowing sub-volume flow, falls after the rainfall event dry (t ₃ in Fig. 2), while chamber B only begins to empty. Not shown in plan view is located in chamber B is a buoyant device 10, which can absorb and bind lightweight materials and may also be provided with microorganisms for biodegradation of light materials (Fig.l) ..

Fig. 3 shows the same device as Fig. 1, here exemplified in a rectangular design. Fig. 4 shows the floor plan of an alternative

Distribution chamber A. This has an inlet 4 and two processes 14 and 15. This distribution chamber A is to be arranged at high altitude on a cleaning device. First, the rinsing surge flows to the distribution chamber and undisturbed again via the lower drain 14 through a partially filled pipe from here (time ti) and a chamber B. With increasing filling level of the chamber B rainwater accumulates back into the distribution chamber, the water level 11 in the distribution chamber A rises (time t ₂ ) on the top Kote of the lower sequence, the drain line downstream flow 14 is full. Once the water level 11 in the Distribution chamber reaches the Sohlenkote 15a of the upper drain 15, jumps to 15 and the flushing surge temporally following flow rate no longer flows from the drain 14, but from the flow 15 out of a cleaning device. (Time t ₃ ).

Fig. 5 shows in cross-section and Fig. 5a in plan view the conversion of a basin with prior use with a method of pure gravitational separation. The chamber for the rinsing surge is exemplified in this basin divided into two chambers B and B2, which each have their own cleaning device 6, for example. The hydraulic separation takes place here by way of example mechanically by means of float-controlled flaps 17a and 17b. By compared to gravitational separation significantly higher cleaning capacity per volume released space in chamber D is used for further purification stages, such. For example, for a Koaleszenzabscheider 20 and a floatable device 10, material that can absorb and bind lightweight materials and may also be provided with microorganisms for biological degradation of light materials.

Fig. 6 shows in cross-section and Fig 6a in plan view another embodiment of a pelvic equipment. The pool is exemplary divided into three chambers (A, B, C). The two chambers B and C each have their own cleaning device. Chamber A is the distribution chamber. Through the line 4, the rainwater flows into the chamber A of the device. The hydraulic separation takes place here for example by means of nozzle-shaped opening 5 in the partition 18a with inlet to the chamber B. At time t ₃ , when the chambers A and B are filled, the further inflowing water overflows the partition wall 18b via an overfill edge 23b in the chamber C. In cross-flow technology, the dry cleaning device 6b is overflowed and thus permanently purged.

The filling of the chamber B with the first sewage surge occurs at the time t ₂ on the raid edge 23a. The filter 6a is also permanently overflowed and thus rinsed free. The sludge accumulates in the sludge chamber 22. The sludge can be withdrawn as needed or continuously with pumps. Via the lines 26 all compartments can be emptied. The baffle walls 24a, 24b prevent the return of lightweight materials on the filter 6a and the chambers A and C. The cleaning device 6 is exemplified. It can also be made in a different shape, for example as a free-standing device in the chamber B, C, as shown in Fig. 5. The filters may be box-shaped, plate-like or formed in a freely selected shape. Instead of the freestanding construction, integration on or in the side walls is possible. In lack of space, the Filter devices in the side of the pelvis arranged shafts, which are connected with lines to be accommodated.

Fig. 7 shows the system structure in a further embodiment variant with several basins Bl, B2, B3. It can be created either several basins B or more basins C. "B" stands for sinks for rinsing; "C" refers to basins for the temporal following partial flow. The illustrated pool C is, for example, an existing rectangular pool that is being reused.

Fig. 8 shows a further, the cleaning performance for lightweight materials improving device with a pre-throttle flow 7 mounted diving bell. Due to the described strong throttling and / or delayed emptying lightweight materials will rise to the surface. The restricted volume flow can not pull the lightweight materials down under the surface of the water like an immersion wall separating from the drain pipe, even if they pass through the filter. For massive oil entry, as occurs in accidents, the throttle sequence 7 can be additionally provided with a standard self-closing valve (not shown). Fig. 9 shows a further embodiment of a distribution chamber A. This has a device 28 which is connected downstream of the inlet .4. The chamber 28 may be at rapid inflowing volume flows are used in feed 4.

10 shows the temporal aspect of the process sequence in the case of a rain event as a graph. The rain event is displayed as a curve. Axis Q denotes the amount of water, axis t the time component. S is the rinsing surge in ti and T is the subsequent partial volumetric flow in t2. Fig. 11 illustrates the temporal shift of the rainwater treatment. In this variant, the rinse is collected and delayed the cleaning supplied. The rinsing surge S: ti and the partial volume flow B: t ₂ is filtered via the strong restriction Qi only after the time interval ti. U is the name for the speed.

FIG. 12 explains a further variant of the time shift. The rinse A is collected and immediately throttled Qi supplied to the cleaning. This variant also shows a temporal reversal, since due to the strong restriction Qi, a large part of the purge surge (S) accumulating first in time leaves the treatment stage after the expiration of the subsequent partial volume flow (T). For particularly long rain events, it may happen that the partial volume flow outflow (T) exceeds the duration of the flushing flush treatment (S). In the figures 10 to 12 means: ϊWeiteit = QAnfaii;

Treated ^<<: U seizure / 'Qmax Tb _Θ acts' Qmax long

Fig. 13 shows the volume flow-based deposition technique realized in many techniques. This hydraulic type of separation above the water level can not detect smaller hydraulically not pronounced rinsing volume flow rates <Qi.

In Fig. 14, the much less realized separation by time units ti; t ₂ shown. This type of separation requires a technical solution. Both

Separation techniques (Fig.13 + 14) have in common that the partial flow T is discarded untreated. In FIGS. 15, 16, 17, the process sequence of a precipitation event is shown in a different way in three time steps ti, t ₂ , t ₃ . A is the distribution chamber; S the rinsing surge and C the partial volume flow.

Compilation of the reference signs A distribution chamber

B chamber for flushing rinse

B ₂ Additional chamber for flushing surge C Chamber for cleaning device for partial flow

D Volume to be used when retrofitting tanks

ti, t ₂ , t ₃ times

I outer wall entire basin 2 partition between chamber for flushing surge and distribution chamber

3 Partition wall between distribution chamber and chamber for cleaning device

4 Inlet pipe, 4a: Penetration of inlet pipe and distribution chamber

5 a / b nozzle-shaped openings

6 Apparatus for cleaning the rinsing surge 7 throttled drain purified Spülschwall

8 cleaning device for in the inlet of the rinsing surge temporally following, but first in the process to be cleaned partial flow

9 expiration of the device

Floatable device with materials which can absorb light materials and possibly enriched with microorganisms, e.g. pads; roll

I 1 water level in distribution chamber

12 water level in collecting volume Rinse

13 inlet opening of the distribution chamber

14 Lower outlet of the distribution chamber (leads to surge volume in the pipe) 15 Upper outlet of the distribution chamber (leads to the cleaning device chamber in the pipe). 15a: sole of the upper drain

16 check valves

17 Separator a) and b) float controlled valves c) and d) float

18 Partition wall between first and second chambers for flushing rinse 19 Drain line from cleaning device

20 Coalescence technology in the course of the rinse surge filter

21 separator for mud room

22 mud room

23 Raid edge 24 baffle

25 space for coalescing or adsorbents

26 Sludge discharge pipe with non-return valve or valve

27 diving bell for light weight retention

28 distribution chamber with device

Claims

claims

1. A method for cleaning rainwater, especially of street sewage, wherein the volume flow of the rainwater is separated in case of sufficiently large rainfall time in an earlier first flow and a temporal Teilström followed, characterized in that at least the predominant part of the first partial flow of the

Regenabwassers is passed into at least one collecting volume, which is hydraulically decoupled from the flow of the following partial flow, that both partial streams are supplied to a cleaning, that at least the collected partial flow is separated by a cleaning process of pollution, which is more efficient than pure gravitational separation 2. Method according to claim 1, characterized in that it is combined, at least for the temporally first partial flow with a method even higher cleaning performance than the screening or filtration.

3. A device for cleaning rainwater, in particular street sewage, according to the method of claim 1, wherein the volume flow of the rainwater in case sufficient large rainfall is temporally separated into a previously flowing first partial flow and a temporally following partial flow, characterized in that at least the major part of the first partial flow of rainwater is passed into at least one collecting volume, which is hydraulically strongly decoupled from the flow of the following partial flow, both Partial streams are supplied to a cleaning that at least the collected partial stream is separated by a higher quality cleaning method as sedimentation of pollution

4. An apparatus for cleaning rain waste water according to one of the method according to claim 1 or 2, characterized in that it consists of at least one component with which a device for collecting rainwater or a basin for gravity separation can be equipped so that in combination with the device is the cleaning of waste water according to one of the methods of claim 1 or 2 possible.

5. An apparatus for cleaning rain waste water according to one of the methods of claim 1 or 2, characterized in that at least one collecting volume is designed as a ground basin. -23 -

6. A device for cleaning rainwater waste according to one of claims 3 to 5, characterized in that it is combined, at least for the temporally first partial flow with a method even higher cleaning performance than the screening or filtration.

7. A device for cleaning rainwater waste according to claim 6, characterized in that the higher cleaning performance is achieved by at least one device with a mode of action according to the principle of coalescing.

8. A device for cleaning rainwater according to claim 6, characterized in that the higher cleaning performance is achieved by at least one device for adsorption of contamination.

9. Apparatus for cleaning rainwater according to

Claim 6, characterized in that the higher cleaning performance is achieved by at least one device containing materials which can absorb light materials.

10. An apparatus for cleaning rainwater waste according to claim 9, characterized in that suitable microorganisms are introduced into the device, which degrade absorbed light materials.

11. A device for cleaning rainwater waste according to claim 6, characterized in that the higher Cleaning performance is achieved by the addition of active ingredients.