EP1741845A2 - Method and device for purifying rain water - Google Patents

Abstract

In a process to trap and discharge storm water from roads, car parks or airports, the first flush bears a higher pollution load than the subsequent second flush. The first flush is discharged directly to a discrete drain pipe (18) separate from the second flush storm water which is discharged to a second pipe (16). The first flush water bears a higher concentration of pollutants and is directed to a high-performance water treatment system, while the larger volume of second flush storm water is discharged to a filter and thence to a lake, lagoon or river. In a further embodiment the unfiltered second flush storm water is discharged to a drainage well.

Description

The invention relates to a method and a device for cleaning rainwater according to the preamble of claims 1 and 2.

Rainwater from surfaces such as lanes, roofs or parking areas or other non-water permeable surfaces are collected in gutters or infeed shafts and the like. If the wastewater is not collected or seeps into ditches or sideways, this will lead to soil pollution.

Many pollutants contained in road effluents can not biodegrade. Consequently, they lead to a continuous accumulation in the soil matrix and can affect the groundwater in the longer term. It has been known for some years that rainwater washes pollutants off surfaces. It has been found that with the first four to six or possibly more liters of water per square meter, a larger amount of dry dumped contaminant load is rinsed off than with the following volume flow. The term first-flush, FF for short, has been established for this water pollution load. The subsequent, longer-lasting rain event that impinges on the pre-rinsed surface at a later time, usually flows much less dirty. In the derivation, therefore, a very different pollution load in the FF and in the subsequent second flush (SF short) can be observed. To a large extent, this distribution is heavily polluted versus very slightly polluted for roof drainage of smaller roofs. Therefore, often at least the highly effective technical applications in wastewater treatment for roof sewage often focus exclusively on the FF. In the case of roof waste water, SF usually targets infiltrations of untreated or less intensively treated wastewater and the use of rainwater. at Wastewater from traffic areas and very large roof areas, however, the freight rates must be considered here in a much differentiated. Depending on the topology of the catchment area, eg. B. with low inclination and / or with hollows or potholes or a small gradient over long distances, as they can be present at airfields or on very large roof areas at runways, it can happen for very long-lasting rain events low intensity that the early occurring flow due to lack of drag force in general and lack of rinse impact z. B. for depressions and potholes is no longer able to rinse the dirt load from the traffic area. This results in a heavy pollution of the SF. For this reason, in the case of waste water from traffic areas, the SF should generally also be subject to cleaning. Ideally, this SF cleaning should also be designed to keep heavy metals from both soils and biological cleaning equipment, for example. In this sense, z. B. infiltration and topsoil passages and retention soil filter still prove to be the wrong way the wastewater experts, since here in the long run accumulation of inert materials such as heavy metals, brake wear u. Ä. In large quantities of soil will result.

It is well known that rainwater discharged into the municipal sewage system causes considerable disturbances in the wastewater treatment and causes correspondingly high operating costs. It is therefore advantageous not to mix clean rainwater from the SF with the dirty water of the FF. Further, it is advantageous, especially not to direct the FF in municipal wastewater treatment plants, since these systems are not designed to wastewater from the special ingredients of road and traffic surface wastewater, such. As different heavy metals to clean. Since water purification systems are generally not designed so that they treat the entire accumulating water, even in heavy rain events, the sewerage system is usually rinsed several times a year in the receiving water. Of the Transported dirt is therefore untreated, but discarded very diluted. In particular, the rainwater discharged into the combined sewage system wastewater but regularly contain non-biodegradable ingredients such as PAH or heavy metals, tire abrasion, etc. This will lead to environmental damage in the medium to long term.

There are already known facilities with which the dirty first-flush water and the less polluted second-flush water can be separated (for example EP-A2 1 129 756 ). Often it is not possible. Rainwater directly at the point of its seizure after cleaning directly (eg by infiltration) to eliminate. It must therefore be collected along the catchment area and can only be returned to nature at a remote location. For the linear collection of rainwater, z. B. in gutters at parking and other traffic areas, in linear gutters or linearly arranged gullies with multiple discrete collection points along traffic areas but the separation sharpness with respect to cleaning systems, which are located at the end of a collection line ("End ofPipe"), depending on The length and shape of the leading sewage system decrease more and more. Because the second flush of wastewater, which comes from areas near the wastewater treatment plant, will reach the facility for cleaning the FF earlier than the first flush of more remote areas. Consequently, the longer the catchment area, the greater the FF treatment volume per unit area has to be selected in order to detect even further FF accumulation and the more the disadvantageously the cleaner SF mixes with the soiled FF of more distant surfaces. The necessary catchment volume thus increases disproportionately with the catchment areas becoming larger than the catchment area. In long river basins, the effluents of FF and SF may even mix so much that separate treatment becomes difficult. Thus, these known methods of linear collection, end-of-pipe separation, and remote delivery to nature have several disadvantages.

In addition, End of Pipe treatment plants are dimensioned for the FF event, ie the first highly effluent water discharged is collected in a separate container. Such a plant, which is dimensioned for example for one hectare of road surface, needs a FF collecting volume of 40- 60m ³ . A volume for which there is hardly any room in many places. If the catchment area is stretched very long, an even larger volume is needed for the same catchment area.

An object of the present invention is therefore to provide, in particular for the waste water of traffic areas and for large roof areas, a method and a device for cleaning rainwater, which for the linear collection and the subsequent transfer to the interface with nature and / or the Cleaning End ofPipe significantly reduces mixing of heavily soiled first-flush water with significantly less contaminated second-flush water before cleaning. Advantageously, by this method and by this device for rain events, which are not to be regarded as exceptionally strong, the majority of the wastewater incurred, ie both the FF and at least the majority of the SF.

This object is achieved by a method and a device according to the features of claims 1 and 2. Advantageous embodiments of the system are described in the dependent claims.

The method according to the invention and the device according to the invention make it possible to largely separate the two wastewater qualities hydraulically by means of a separate derivation of the FF volume flow and the SF flow rate, which is considerably larger for large rain events. The heavily loaded FF wastewater can be in at least one line z. B. with a small cross-section and / or throttled drain directly or throttled by other means a suitable cleaning device to be supplied. The SF water on the other hand, it can be treated independently, eg filtered, or end-of-pipe z. B. derived on a leaching area or passed into a body of water.

When throttling the drain from the FF line End of Pipe, the heavily polluted amount of water compared to the unthrottled volume in substantially lower flow rate of further treatment can be fed. By using a small-sized pipe or a locally throttled line with small-sized flow for the heavily polluted FF water is achieved that the throttled pipe serves as a temporary storage space and the collected water at the beginning of the rain event still at high speed and thus high drag force flows.

The less frequent SF events, which are dissipated in separate lines, often entail virtually no particulate matter, silt or fine sands, etc., which may build up in the lines and then lead to blockages. The self-cleaning of the lines results in a substantial reduction of the maintenance and flushing effort, and thus a high cost savings with higher reliability.

The method and apparatus may be integrated into existing drainage piping systems. Appropriately designed inlet shafts as well as an additional small-caliber small-volume line or at least one additional large-caliber line through which either the separated FF or SF flows are required. To use this line as storage space this is to throttle. First-flush collection volume therefore primarily means that only small amounts of water flow out of it per time or, if appropriate, it ends at the end of line sections or at the end of the line into a collecting volume from which smaller quantities flow out per time. The design of the inlet allows an inflow amount that is significantly greater than the maximum possible outflow. The latter can be located next to the existing main line or in a separate small-caliber pipe adjacent to the main pipe or even inside the main pipe.

• ob es neben dem Volumen oder den Volumina für den FF ein oder mehrere Volumina oder Ablaufleitungen für Teile oder den gesamten Second-ffush gibt,
• an welcher Stelle und mit welchen Verfahren eine Reinigung des gesammelten FF-Volumen stattfindet und davon, an welcher Stelle und mit welchen Verfahren eine Reinigung des SF stattfindet
• wie die Aufteilung der Regenspende in einen zeitlich ersten und bei ausreichender Regenspende ggf. in einen zeitlich folgenden Abfluss konstruktiv realisiert wird und somit auch davon, ob dies z.B. durch Anordnung von Ab- resp. Einläufen in das/die FF-Auffangvolumina in unterschiedlicher Höhenlage oder z.B. durch Anordnung von Ab- resp. Einläufen zu dem/den FF-Auffangvolumina in Fließrichtung oberstrom der Ableitung des SF oder ggf. mit Einsatz von Pumpen oder in beliebiger anderer geeigneter Weise realisiert wird,
• von der konkreten Ausformung des FF-Auffangvolumens, rund, oval, eckig oder beliebig anders geformt, ob als eine oder mehrere Leitungen am Stück oder in mehreren Segmenten oder in nachgeschaltet angeordneten einzelnen Auffangbehältern in genügender Anzahl, ggf. mit oder ohne Verbindung untereinander,
• wo das FF-Volumen/die FF-Volumina relativ zur Wasser spendenden Oberfläche und auch relativ zu ggf. weiteren für verschiedene vorteilhafte Lösungen notwendige Leitungen, Vorratsbehälter, Versickerungsanlagen etc. angeordnet ist/sind. Das FF-Volumen/die FF-Volumina kann/können oberhalb unterhalb, neben oder auch mit nur indirekten räumlichen Zusammenhang zu Flächen, Körpern, Volumina, Anlagen u. ä. angeordnet werden.

The inventive decentralized road drainage of overland roads can be done very effectively and inexpensively. Dewatering can also be achieved by connection to a low-profile FF drain and lateral discharge of the SF into a main line. In turn, FF water is then sent directly to a small-sized and therefore effective treatment. With the system according to the invention, the functionality of the soil filter, in particular in the event of a malfunction, obtained and the risk of pollution can be massively reduced. Pollutants such as oil, gasoline or manure can no longer get directly into a receiving water or to the soil filter. In summary, the method according to the invention is independent of

• whether there is one or more volumes or drains for parts, or the entire second-ffush, in addition to the volume or volumes for the FF,
• at which point and with which method a purification of the collected FF volume takes place and of where and with which method a purification of the SF takes place
• how the division of the rain donation in a temporally first and with sufficient rainfall, if necessary, in a temporally following outflow is realized constructively and thus also of whether this, for example, by arranging Ab resp. Into the / the FF collection volumes at different altitudes or eg by arranging Ab resp. Inlets to the FF collection volume (s) in the flow direction upstream of the discharge of the SF or possibly with the use of pumps or in any other suitable manner,
• from the concrete shape of the FF collecting volume, round, oval, square or any other shape, whether as one or more lines in one piece or in several segments or in arranged individually arranged collecting containers in sufficient number, possibly with or without connection to each other,
• where the FF-volume / the FF-volumes relative to the water-donating surface and also relative to possibly further necessary for various advantageous solutions lines, reservoir, infiltration systems, etc. is arranged / are. The FF volume / volumes may be above, below, or even with indirect spatial relationship to surfaces, bodies, volumes, equipment, and the like. Ä. Are arranged.

Figur 1

eine Aufsicht auf einen Straßenabschnitt mit zwei erfindungsgemäßen Anlagen,

Figur 2

einen Vertikalschnitt längs Linie II-II in Figur 1 durch einen Schacht,

Figur 3

einen vertikalen Schnitt durch einen Trenn-Kontrollschacht

Figur 4

einen Querschnitt durch eine Straße mit seitlicher Entwässerung,

Figur 4a

einen Querschnitt durch eine weitere seitlich der Straße angeordnete Entwässerung,

Figur 5

eine weitere erfindungsgemäße Ausführung des Schachts mit einem in der Hauptleitung angeordneten Kleinmengenablauf,

Figur 6

eine weitere erfindungsgemäße Ansicht einer Rohr in Rohr Anordnung.

Figur 7

eine rinnenförmige Rohr in Rohr Anordnung mit Mitteln zum Reinigen des Regenabwassers innerhalb der Rohre.

Based on illustrated embodiments, the invention will be explained in more detail. Show it

FIG. 1

a view of a road section with two systems according to the invention,

FIG. 2

a vertical section along line II-II in Figure 1 through a shaft,

FIG. 3

a vertical section through a separation control shaft

FIG. 4

a cross section through a road with lateral drainage,

FIG. 4a

a cross section through a further arranged laterally of the road drainage,

FIG. 5

a further embodiment of the shaft according to the invention with a small amount of drain arranged in the main line,

FIG. 6

a further inventive view of a pipe in a pipe arrangement.

FIG. 7

a gutter-shaped tube in a tube arrangement with means for cleaning the rainwater within the tubes.

In the schematic representation of a road 1 in Figure 1 is denoted by reference numeral 3 to be dehydrated road surface. In the middle of the road 1 is a drainage channel 5, which may be constructed, for example, of stone blocks, visible. At intervals 5 inlet chutes 7 are arranged in the drainage channel. Side of the drainage channel 5 a sewer system 9 is shown in broken lines.

This can of course also be below the drainage channel 5. The drainage channel 5 can be arranged in the region of the green strip. The cross-section through one of the shafts 7 according to FIG. 2 shows that the sewage system 9 in the first exemplary embodiment comprises two separate lines, namely a small-volume channel 18 and the main channel 16. The small quantity channel 18 is connected to the inlet shaft 7 by a small quantity line 22 running here by way of example and preferably inclined to the horizontal. The small quantity line 22 opens at a lower point of the inlet shaft 7 in this. Preferably, the shaft bottom 24 is also arranged inclined to the horizontal. At a distance h ₁ above the mouth of the small volume line 22, a main drain line 20 opens into the wall 21 of the inlet shaft 7. The main drain line 20 has in the first embodiment shown in FIG 2 a much larger diameter than the small quantity line 22. In the extension of the also preferably inclined main drain line 20, a grate 14 may be used, which completely spans the cross section of the inlet shaft 7. The grate 14 may be formed as a grid or as a perforated plate suitable permeability and serves to prevent clogging of the small quantity line 22. In the plane of the road surface here is exemplified provided with openings navigable cover or grate 12, softer the entry of surface water into the shaft 7 allowed. The cover 12 preferably extends over the entire shaft cross-section. In another embodiment, not shown, the cross section of the small quantity line 22 is dimensioned similar to that of the main drain line 20. At the outlet end of the small quantity line 22, a throttle or a valve is placed in order to reduce the temporal outflow quantity. The small quantity line 22 serves as a temporary storage space. Between the small quantity line 22 and the space 7 'above the grate 14, a vent line 28 may be arranged. The vent line 28 may also open into the space 7, to the surface or to any other suitable location.

In a further embodiment of the invention (FIG. 5), a sewer pipe 60, which is subdivided by an intermediate wall into a main channel 16 and a small quantity channel 18, replaces the main channel 16 and the small volume channel 18. The main channel 16 is connected via the Hauptabfiussleitung 20 and the small quantity channel 18 via the small quantity line 22 in connection with the shaft 7. Instead of a partition, an additional pipe, namely a small amount of pipe 18 may be inserted into the large pipe 16 (Figure 6).

Figure 3 shows a schematic cross section through a separation control shaft 30, in which the main channel 16 and the small quantity channel 18 open, if the water discharged through the main channel 16 and the small quantity channel 18 does not directly a wastewater treatment plant or a body of water or infiltration or process water With an optional throttle, orifice or a slider 38, the inflow from the small quantity channel 18 into the inspection shaft 30 can also be adjusted. This makes it possible to dimension the volume of the inspection shaft 30 relatively small and to use the volume of the small quantity channel 18 at least temporarily as storage space. Without throttling additional storage space must be provided. The small quantity channel 18 opens directly into the outer annular space 44, also called first-flush space. For this a Schmutnvasserleitung 32 leads to the wastewater treatment plant. Alternatively, a cleaning device according to FIG. 3 for the FF can be provided within the shaft 30. A connection to an ARA is then not necessary. On the inlet side, a backflow flap 34 may be attached to the dirty water line 32 in order to retain on the one hand channel odors from the combined sewage system and to prevent backflow from the sewage system into the inspection shaft 30. The main channel 16 with relatively clean SF water flows directly through a filter 40 into a storage space 42. In this impurities are retained by the filter 40 and can with the FF water or separately be supplied to the sewer. The SF water passing through the filter 40 flows through an outlet here, for example, to a sipper girdle 36 from which infiltration into the ground or discharge into a body of water takes place.

In the exemplary embodiment according to FIG. 4, the small quantity channel 18 lies directly below the drainage channel 5, in which, as an alternative to one or more latticed channels, a slot channel inlet 54 can be formed. It is also conceivable to cover with gravel. The drainage channel is preferably formed asymmetrically by on the side of the road surface 3 a to the horizontal against the Schlitzrinneneinlauf 54 inclined portion 55 is present and on the side facing away from the lane 3 side of Schlitzrinneneinlauf 54 a substantially horizontally extending portion 57 is present. The surface of the horizontally extending portion 57 is an amount h ₂ below the Kote of the road at its lowest point. By a lowered portion 52 of the channel 56 adjoining the gutter 56, a lateral broadening 9 of the drainage channel 5 is achieved. The lowered section 52 forms a drainage surface.

FIG. 4 a shows a further embodiment of the embodiment according to FIG. 4. In addition to the small quantity channel 18, the main channel 16 is arranged. This is above a correspondingly sized slot-shaped opening 59 with the surface in combination. Also in this embodiment may laterally additionally a deeper-laid portion 52 may be formed, in which a direct infiltration into the ground is possible if too much SF-water accumulates and can not be absorbed by the main line 16.

FIG. 7 shows the cross-section of a channel-shaped tube in tube solution, in which the rain wastewater flows in via the perforated cover 64a of the channel 62 and then flows first through the cover 64b and filter 66a to finally reach the small-volume channel 18. If the water from the small quantity channel 18 back, the following volume flow pours through filter 66b in the main channel 16. This device can also without the Means for cleaning 66a and 66b are performed and instead lead to a system with FF and SF cleaning.

The operation of the system is explained in more detail below. At the beginning of a rain event with a small amount of rain per unit of time, the impurities which flow off the surface of the road, a runway or, if necessary, a roof, are drained off the runoff water. For larger roofs or roofs are double gutters - a small next to a larger - arranged. The first would deduce FF and the second only the SF, which can be initiated, for example, after cleaning in the process water. The heavily loaded by impurities FF can be completely swallowed and discharged from the small volume channel 18. Through the small quantity channel 18, the contaminated FF water also passes either directly into a water purification system or into a control shaft 30 according to FIG. 3, which also serves as a stowage or temporary storage space, if the flow of the first-flush is throttled. If it remains with a small amount of precipitation, so no water comes into the main channel 16 and the entire polluted, heavily loaded water can be fed directly to the cleaning. Increases, however, the amount of time precipitation, so the small volume channel 18 can no longer dissipate this amount and it gets the much less polluted second flush water in the main channel 16. Through this, the little polluted water can be directed into a control shaft 30, where a Filtration to remove solids occurs before the water follows infiltration or discharge into public waters.

It is also advantageous, cleaning agents such. As filter cloths or filter fleeces to install within the channel 18 and / or channel 16, which subject the resulting streams after passage of the inlet shaft 7 already on their flow path through channel 18 and / or 16 a cleaning. If z. B. small quantity channel 18 in Fig. 6 as Hose made of filter fleece created, the purified FF can flow filtered from small-volume hose channel 18 in channel 16, the contaminants are retained in small-volume channel 18. For the SF a corresponding Reinigungsvornchtung within the channel 16 is conceivable. Advantageously, the channel tube can be fixed so that he, z. B. at the inlet ducts 7 or elsewhere pulled out of the line and can be replaced by a clean tube.

Legend / reference

1 street

3 road surface

5

drainage channel

7

inlet shaft

9

sewerage

10

Shaft cross-section

12

drivable cover or rust

14

rust

16

main channel

18

Small amount channel

20

Main drain line

21

wall

22

Small amount of tap

24

shaft bottom

28

vent line

30

inspection chamber

32

Sewage line

34

return flap

36

Sickerrigole

38

throttle

40

filter

42

Storage space for second flush

44

First flush room

46

procedure

50!

Road section

52

lowered section

54

Slot gutter inlet

55

inclined section

56

ground

57

horizontal Absqhnitt 59 slot opening

60

sewer pipe

61

partition wall

62

gutter

64a, 64b

perforated covers

66a, 66b

filter fabric

Claims (12)

Method for cleaning rainwater, in which the volume flow of rainwater in case of sufficiently large rainfall time in a previously flowing first partial flow (FF) and a temporally following second partial flow (SF) is separated, characterized in that at least the greater part of the earlier in time flowing partial flow (FF) along the surface to be dewatered separated from later in time flowing partial flow (SF) is collected and fed to a cleaning process. A method according to claim 1, characterized in that at least parts of the FF and / or at least parts of SF within discharge means along the surface to be dehydrated are fed to a process at least partially cleaning the rainwater. Apparatus for purifying rain waste water according to the method of claim 1, characterized in that for the earlier flowing first partial flow (FF) along the surface to be drained separate means for collecting, discharging and / or storing at least the major part of the first partial flow (FF) and are arranged for collecting and discharging at least parts of the following partial flow (SF). Apparatus for purifying rain waste water according to the method of claim 1 or 2, characterized in that within means for collecting, discharging and / or storing the first partial flow (FF) and / or the following partial flow (SF) means for at least partially cleaning the rainwater are arranged. Apparatus according to claim 3 or 4, characterized in that the means for collecting the temporally earlier flowing first partial flow (FF) by a plurality of selectively arranged individual collecting volumes along to be drained Surface are formed and / or that at least at one portion along the surface to be drained at least one line-shaped collecting means is formed. Device according to one of claims 3 to 5, characterized in that the / the means for collecting, discharging and / or storing are formed as tubular body. Apparatus according to claim 6, characterized in that the means for separate collection, discharge and / or storage of the temporally first partial flow (FF) and temporal subsequent partial flow (SF) as a tube in the tube or as divided by at least one partition multi-tube, in particular as a double tube are executed. Device according to one of claims 2 or 3, characterized in that the means for the separated collection, discharge and / or storage comprise at least one shaft, above the bottom of a small amount line (22) for the first-flush (FF) and at a distance ( h ₁ ) via a main line (20) for the second-flush (SF) opens and that the volume between the small-volume line (22) and the main line (20) as a volume for catching, deriving and / or buffering for the first flush (FF) serves. Device according to one of claims 3 to 5, characterized in that the means for collecting, discharging and / or storing are formed as a groove, which are capable of receiving the first partial flow (FF) and that the second partial flow (SF) over this gutter away - and its own separate gutter flows. Apparatus according to claim 9, characterized in that in addition to this device a seepage is arranged for by the discharge means not tangible volume flows. Apparatus according to claim 4, characterized in that the means for cleaning are linear, so that they can be pulled out at individual points from the collecting and discharging means and clean funds can be recovered. Device according to one of the preceding claims, characterized in that means for collecting, discharging and / or temporarily storing the FF open at one point or in sections in systems for cleaning, which clean the FF at least by filtration.

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