DE19755447A1 - Waste water treatment basin having spiral-walled channel - Google Patents

Abstract

A waste water treatment basin has an inlet and an outlet. The basin has a wall which in plan-view extends in a spiral shape from the inlet to the outlet. Either the inlet or the outlet is on the periphery of the basin, and the other either inlet or outlet is at the center. The water is agitated as it flows along the spiral channel.

Description

The present invention relates to a wastewater treatment tank with inflow and outflow and a process for wastewater revitalization.

The wastewater, as it occurs today in cities and communities, is loaded with different ingredients that come from the Waste water must be removed before it enters natural waters can be drained. First there is a mechanical one Wastewater treatment to remove coarse components such as wood, cans, etc., as well as water-insoluble ones Suspended matter such as sand is common; however, the wastewater is further also loaded with a variety of ingredients contained in it are solved. These are especially organic Substances to phosphorus compounds, especially phosphates, as well as nitrogen compounds, with stick in the raw sewage Almost exclusively as ammonium nitrogen, i.e. in form of ammonium ions, as well as in organic compounds whose form occurs.

The natural self-cleaning of most natural waters is under practice with today's requirements for water protection sewage pollution not sufficient to support this substance zen to degrade quickly enough so that it can be discharged through waste water cleaning in sewage treatment plants must be removed or dismantled.

Nowadays, the clarification is typically done as biological Clarification, whereby the implementation of the substances mainly through Mi microorganisms occur in so-called wastewater aeration tanks, with a variety of different reactions taking place.

For example, nitrogen is removed from waste water by first reacting the nitrogen bound in the raw waste water as ammonium nitrogen or in organic compounds to nitrite ions, NO ₂ ,; this is done in particular by Nitro somonas bacteria. The nitrite formed is then oxidized to nitrate, NO ₃ ⁺, for which purpose Nitrobacter bacteria are used.

After this conversion of the raw sewage as ammonium ions Contained nitrogen to nitrate can the wastewater through white other bacteria can be denitrified. The denitrifying Bacteria use the im under oxygen deficiency conditions Nitrate-bound oxygen for the oxidation of carbon. This requires organic compounds in the wastewater and settles on the one hand gaseous carbon dioxide and on the other hand gaseous free of nitrogen.

The bacteria used for the various degradation reactions s need different conditions to get the best To ensure material turnover. So it is for the Nitrosmo nas bacteria, which contains the ammonium contained in the raw sewage Convert nitrogen to nitrite, cheap, relatively high ammonium find concentrations; but concentrations are too high again for the Nitrobacter bacteria, which subsequently the converts nitrite produced by the Nitrosomonas bacteria to nitrate zen, toxic. In addition, the growth rates are ever different bacteria. Because a slower one Growth goes hand in hand with a lower substrate turnover the bacteria have different long times for the um setting of substances.

While it is therefore possible in principle, the wastewater live in a mixing basin, in which the Reak running in parallel, it is for the formation of a lei sustainable biocenosis, d. H. a powerful, unit community of the bacteria that break down the pollutants rien, advantageous, an aeration tank with tubular reactor characteristics planning. These have raw sewage on one side fed that the tubular reactor essentially without through mixture, and thus generally like a plug flow through running. The aeration tank length will be different Activation zones are provided, for example by the selek tive blowing in air and / or supply of be agreed substrates, etc. happens. So in the respective  Zones favorable conditions can be set. After the through When the pipe reactor runs, the waste water then emerges from the pipe actuator pool from.

As an aeration tank with tubular reactor characteristics, one on the one hand rectangular pools and on the other hand oxidation tanks set.

Such basins or trenches must be very long in order to usual flow rates an adequate implementation to ensure the contamination. However, long pools are already because of the space requirement, but also because of the high construction wall expensive. They are particularly unfavorable when due to geological or geophysical subsurface activities, such as such as subsidence, large pools must be avoided, so that so far only mixing basins could be used here.

Another problem with such aeration tanks is that the Utilization of a sewage treatment plant with regard to both wastewater quantity as well as the impurity concentrations in many cases fluctuates, especially in places with seasonal tourism. A cost-effective decommissioning of individual plant parts is then possible if parallel activation tanks are provided and during low-load periods, some of the aeration tanks completely can be removed from the cleaning line. The provision however, several, anyway expensive cleaning basins increase the be large space requirement for long aeration tanks what is particularly problematic when ge on a site must be built where there is little space available.

The present invention aims to create new for the trade che application.

This task is through the independent procedural and pre solved directional claims, to which advantageous Ausgestaltun conditions are described in the respective subclaims.

A basic idea of the invention is therefore in an Ab water revitalization pool between inflow and outflow one or more right to arrange flow guide walls that extend the flow path  nen. It is based on the knowledge that the usual straight course between inflow and outflow in a waste water Aeration tanks are not essential to achieve good cleaning properties is required. Rather, even then, will be very satisfactory wastewater purification results achieved when streams guiding walls a straight course from inflow to outflow prevent. It was recognized that in particular in the area sharp deflection around certain forms of flow guide walls Stagnation rooms with reduced mixing can occur.

However, if the flow is designed accordingly, these are baffles can be avoided and adversely affect in practice the overall cleaning result may be minor and barely noticeable.

By installing at least one one-piece or multi-link against the flow guide wall between inflow and outflow, it is possible to choose other pool designs as such, in which Inflow and outflow in a rectangular basin linearly far apart are spaced; in other words, through the simple Installation of the cleaning result not affecting that Water diverting water in the horizontal direction those who redirect the water one or more times, a signi fictional pelvic shortening can be achieved, which with limited Space or under unfavorable geophysical conditions gene is particularly advantageous.

The flow guide walls are preferred for at least one essential generally plug-like and especially recircu lation-free flow through the pool. With "pfropfenar tiger pelvic flow "is meant here that, at least least at a sufficient distance from the inflow area, water, that later flowed into the pool, only mixed to a small extent with water, which flows into the pool before or after. Understands that in particular in the inflow area there is a thorough mixing of the newly flowing sewage with already in the basin near the Zu existing water can occur and possibly so is even desirable; it is also clear that, in particular if the wastewater treatment tank in certain areas of is bubbled through with indented air below, here below  A slight mixing will occur without vortex formation that the general plug flow is affected.

An education of the flow baffles that a recirculati ons-free flow through the pool is guaranteed in particular achieved when there is no we through the flow guide walls there is considerable reflux between outflow and inflow, so none Carousel-like circulation of waste water in the pool is possible.

The flow guide walls can be curved or a curvature approximate by a plurality of straight pieces. The provision of the like curved flow guide walls, in particular go through the curved flow guide walls is advantageous in that as stagnation rooms with reduced flow and un Desired deposition of suspended matter, especially with strong Redirection of the flow are expected.

It is advantageous if the flow guide walls at least in the essentially form a spiral, because in this way a plug-like pelvic flow with at most small and generally non-disruptive stagnation rooms while achieving ei long flow path with the smallest possible basin dimensions while avoiding large distances between inflow and outflow can be achieved. With such an arrangement, one of Inflow and outflow inside the spiral and the other outside the spiral can be arranged; so it's either possible a flow of the spiral from the inside out or other to achieve from the outside inwards.

The provision of a spiral as a flow guide wall is special then advantageous if the wastewater load fluctuates greatly is to be expected. This shape makes it particularly easy to ins especially with central feeding, with short, flexible or otherwise movable supply lines for air and / or ge possibly other substances in the basin different Define activation zones along the spiral. So can the activation process of a different waste water adapted by various pollutants and contaminants the. In particular, the number of different ones Activation zones within the basin according to the invention are easy  can be varied. Then the waste water Bele invention exercise pool yet another, conventional or fiction as provided with flow guide walls, as a rectangular or Round, designed, preferably small, aeration tank optionally switchable upstream or downstream, so can be weak the rest of the basin is completely out of the clarification process be removed and the wastewater in all stages along the Ab water revitalization basin can be cleaned. It is through the Variation of the activation zone position, number and length especially easily possible, not only the amount of wastewater, but also to adapt to its respective load. In heavy load times the other pool simply switched on again and explored if necessary, one or more activation levels in this Bec ken shifted back inside. In this way, through the temporary decommissioning of a complete pool in respectable chem measures operating costs can be saved.

A particularly simple construction of the activation area kens results when the spiral is separated by circular segments of be preferably 270 ° is formed, which are connected with straight pieces. The circle radii grow from the inside of the spiral to the outside of the spiral ren particularly so that each spiral of the spiral in provides approximately the same flow width. This he facilitates the offset of the definition of different Be ventilation zones etc. used and results in great freedom unit in determining the positions at which the respective should start and stop at the activation zones.

The wastewater aeration tank is preferred with an inflow provided by a robbery, where then if the wastewater aeration basin is spiral, a central inflow cylinder is provided in the center of the spiral who can, who has a partially lowered rim in Man has tel cylinder. The wastewater aeration tank of the present the invention can be at least essentially round basin be designed.

It will be appreciated that the pool of the present invention incorporates Flow guide walls both from prefabricated, at the site of the clarifier only parts to be connected to each other, especially  re manufactured from precast concrete parts or stainless steel can, just like from in-situ concrete, d. H. on the grounds of the clarifier plant in a suitable formwork for pouring concrete.

The invention is described below only by way of example Drawing explained. In this shows:

Figure 1 is a schematic diagram of a sewage treatment plant with a wastewater treatment tank according to the present invention.

Fig. 2 shows a waste water aeration tank of the present invention from above;

Fig. 3 the basin of Figure 2 in cross section along line III-III;

Figure 4 shows a central raid cylinder for a wastewater aeration tank according to the present invention.

Fig. 5 shows another wastewater treatment tank according to the present invention.

According to FIG. 1, a sewage treatment plant, generally designated 1 , has raw sewage from e.g. B. a large city or a small settlement or community supplied via a sewer 2 .

The raw wastewater is first freed of coarse materials such as wood, cans etc. and possibly suspended matter such as sand in one and coarse and pre-cleaning stage 3 and then flows after detection of its quantity and load at a measuring station 4 in a water treatment tank 10 . In this position changeable and removable ventilation devices and Stoffzulei lines 11 a, 11 b are arranged, which define different activation zones 12 a, 12 b, 12 c. The length of the activation zones can be varied manually or automatically, in particular in response to the wastewater load detected at the measuring point 4 and evaluated on a control s. Behind the aeration tank, the treated wastewater flows via a wastewater switch 6 , which can preferably be controlled automatically by control 5, into a further aeration tank 8 or in the receiving water 7 , ie the natural water receiving the cleaned wastewater. On the way to the receiving water 7 , the wastewater treatment basin 10 according to the invention can in any case be subordinate to further clarification stages, such as secondary settling tanks etc., regardless of the course setting. Furthermore, the sewage treatment plant 1 can comprise digesters, gas containers, devices for sludge treatment and other conventional devices in the usual way.

The wastewater revitalization tank 10, which is only schematically indicated in FIG. 1, is shown in more detail in FIG. 2 with the omission of the air and / or material feeds 11 .

According to FIG. 2, the waste water aeration basin 10 is essentially formed as a circular tank, that is, with a generally circular outer wall 13, wherein the outer wall is not completely circular sen CLOSED, but having a generally tangential water drain fourteenth

In the middle of the generally round sewage aeration basin 10 , an inflow cylinder 15 is provided, the cylinder jacket of which, with the exception of a lowered overflow edge 16 ( FIG. 4), has the same height as the outer wall 13 , cf. Fig. 3. At the Zuflußzy cylinder 15 joins a straight piece 17 tangentially, flush and waterproof. This has the same height as the inflow cylinder 15 and the outer wall 13th At the end of this first straight piece 17 facing away from the inflow cylinder 15, a circular segment 19 joins in watertight and flush, which is coaxial with the inflow cylinder 15 and comprises an arc of 270 °. The circle segment 19 is at the end facing away from the straight piece 17 of the circular segment 19 tangentially extended by a parallel to the first Ge wheel piece 17 straight piece 20 , namely flush and in particular fluid-tight with the circular arc 19 . The second straight piece 20 is at the end facing away from the circular arc segment 19 in turn fluid-tight and flush with a two th, the inflow cylinder 15 and circular arc segment 19 coaxial circular segment 21 is connected. Like the inner circular arc segment 19 , the subsequent circular arc segment 21 also comprises a circular arc of 270 ° of the 360 ° full circle and has the same height as the outer wall 13 and the inflow cylinder 15 (cf. FIG. 3).

So there are gradually enlarged 270 ° arc segments connected by straight pieces, each of the inner circular arc  continue tangentially. In this way it becomes a growing Spiral formed.

A third straight piece 22, which is parallel to the straight pieces 17 and 20 , adjoins the circular arc segment 21 . The outer wall 13 bumps against this. The straight piece 22 continues beyond the fluid-tight joint 23 . Together with a parallel straight piece 24 , which connects tangentially to the outer wall 13 also formed as a 270 ° circle segment, it defines the drain 14 .

In this way the outer spiral end is defined.

The radii of the circular arc segment 13 of the outer wall, the central circular arc segment 21 and the inner circular arc segment 19 as well as the straight piece lengths are preferably selected in the described configuration such that all helical gears have the same width. For this purpose, between the jacket of the flow cylinder 15 and the inner circular arc segment 19 the same radial distance as between the circular arc segment 19 and the central circular arc segment 21 and between the central circular arc segment 21 and the outer wall 13th This radial distance preferably also corresponds to the distance of the straight pieces 22 and 24 to be arranged preferably parallel, so that the outflow has the same dimensions as the spiral passages.

Playpens can be provided across the pool and / or the spiral walls projecting above the water surface 32 are made accessible.

With the described structure of the wastewater aeration tank 10 , a spiral-like or helical or helical configuration is achieved on the wastewater aeration tank. The circular segments 19 and 21 together with the straight pieces 17 , 20 and 22 and the jacket of the inflow cylinder 15 form a generally horizontal flow guide wall, which extend the flow path between inflow 15 and outflow 14 and prevent a direct flow from inflow to outflow.

The spiral of the wastewater aeration tank can optionally have more or fewer turns than shown in FIG. 2 for explanation. 2, in particular, but not exclusively, stainless steel or concrete come into question as the material for the spiral of FIG . When the spiral is made of concrete, it can either be cast on site or made from prefabricated concrete pieces that are only fluid-tight to connect.

In order to achieve a uniform flow through the helical gears, a slope may optionally be present in the bottom of the spiral along the helical path from the inflow in the direction of the outflow, as shown in FIG. 3 schematically by different bottom thicknesses 25 a to 25 f of the successively from the inside to the outside through spiral turns indicated.

In operation, the wastewater aeration tank of the present invention is flowed through by wastewater which, after the rough cleaning, flows in via the overflow edge 16 of the inflow cylinder 15 . Since at near the inflow cylinder 15, a mixing area 26 is formed by the overflow, where freshly flowing water is swirled and thus mixed with waste water already present in the wastewater treatment tank. However, the mixing area 26 does not extend too far away from the inflow cylinder, so that at a distance therefrom a uniform flow of the waste water serbeebebanks without substantial mixing of the freshly flowing in with the waste water already present in the pool. In this almost plug-like flow through the water revitalization basin, the water is passed through the flow guide walls. The flow is essentially completely uniform, especially along the circle segments. Small stagnation spaces only arise on the inside and outside at the sharp corners with transitions between straight pieces and circular segments.

Although such stagnation spaces the achievement of a satisfactory not endanger wastewater treatment, it is easy possible to avoid their appearance simply by using sharp Corners and edges can be avoided. He can do this, for example be enough by a bump between the straight piece and Circular arc segment with a sufficient radius of curvature inside  and / or rounded off or by the transition in shape a polygon segment is designed. One more way to avoid stagnation spaces is instead the described, gradually increasing circular segments te, which are connected by straight pieces, a continuous Spi rale as a flow guide wall without corners and edges. This can also be done by using arches instead of Ge wheel pieces happen.

The wastewater is then revitalized along the flow path, i. H. cleaned. To different activation zones, in particular to be provided for aerobic and anaerobic processes the bottom of the wastewater treatment tank along the spiral bare and, if necessary, removable feed lines and / or Air inlet pipes arranged, which via flexible lines with egg ner compressed air source like a sufficiently strong pump they are.

Preferably, one per se is preferred in the vicinity of the inlet known microbial phosphate redissolution. Successor A denitrification then becomes prevalent in the middle pelvic area and nitrification in the rest of the pool area men. Such denitrification before nitri The specification does not correspond to the sequence explained in the introduction the biological nitrogen conversion process. but she is cheap because already in "biologically correct" order before the nitrate reduction, the organic ones present in the wastewater Connections are largely cleared and then no longer available To be available.

The nitrate breakdown can then only via endogenous respiration operations take place, d. H. using memory substance zen previously collected by the organisms, or by Lysis products. Such endogenous reactions take place in the Usually slow, what about long stays in the Denitrifika tion stage for extensive nitrogen degradation required. This is synonymous with large pool volumes. An alternative would also be an expensive addition of external carbon sources such as methanol and / or acetic acid possible, which is expensive, or one or too a partial flow of raw sewage. Since with the raw sewage  ammonium ions also passed the nitrification stage and the ammonium nitrogen is then no longer broken down cleaning efficiency is impaired.

These problems of the "biologically correct" downstream De nitrification is avoided with the preferred in the invention, upstream denitrification. Here the feed serves Raw wastewater as a carbon source for denitrification. The Nitrate, which is to be broken down in the denitrification stage, but only built up in the subsequent nitrification stage is preferred by partial recirculation of the Ab course of the nitrification stage in addition to a reflux sludge guidance provided. So it becomes part of the target Waste water taken from the nitrification stage and the deni trification fed.

This preferred course of clarification shows that with "recirculations free "in the sense of the present invention a carousel like circulation of the complete amount of waste water is meant, but still a targeted return of part of the revitalizing wastewater is possible from other process stages is specifically introduced at certain points.

The length and number of the respective zones can be set to one way to be determined by ventilation pipes, the What deduction from the nitrification stage and / or the return from nitrate-containing water can be added, for which only short flexible Pipes are required even if there is a ventilation zone around a large flow path, such as a whole spiral wrap lung is changed.

Deviating from Fig. 1 with flowing from the inside of the spiral to the outside of the spiral wastewater (even if the soil inclination is then possibly reversed) a flow in the opposite direction is possible. While a round basin with a central inflow and tan potential external outflow is shown in FIG. 2, FIG. 5 shows, using corresponding reference numerals, a further round sewage-revitalization basin 10 according to the invention with a radially outer region arranged from an inflow overflow edge 28 to the basin separated inflow 29 , which has a central flow from 30 , which is preferably also realized by an over case. In the basin 10 , a flow guide wall 31 is provided, which is constructed like the spiral of the wastewater activation basin of FIG. 2, but instead of sharp impingement th a stagnation space reducing or avoiding rounding between circular arc segments 19 , 21 or outer Rundbec kenrand 13 and the Straight pieces 17 , 20 and 22 .

Although both embodiments of the waste water according to the invention aeration tanks are shown as essentially circular, are other forms of wastewater treatment tanks without further ado conceivable, like oval wastewater treatment tanks with internal flows guide walls, rectangular activation tanks, the inner, lower standing right on the edge of the pool and into the pool protruding flow guide walls or at least one inner flow mungsleitwand between inflow and outflow, etc.. It will also considered that instead of an inner flow baffle Wastewater aeration basin, for example, from prefabricated arcs is built differently, in which case the outside walls of the wastewater aeration basin as flow guide walls nen that extend the flow path between inflow and outflow.

Claims (14)

1. wastewater treatment tank with inflow and outflow, characterized in that at least one flow guide wall is net angeord between these. 2. Wastewater treatment tank according to claim 1, characterized records that the flow guide wall or walls for a recirculation-free and in particular, at least essentially lichen, plug-like flow through the basin, ins is / are particularly curved. 3. wastewater treatment tank according to claim 2, characterized records that the flow guide wall / walls at least in essentially, forms a spiral. 4. Aeration tank according to claim 3, characterized indicates that one of the inflow and outflow in the spiral interior, especially the spiral center, and the other one on the outside rich of the spiral, especially at the end of it is arranged. 5. wastewater treatment tank according to one of claims 2 to 4, characterized in that the spiral by Ge Circle segments of preferably 270 ° connected with wheel sections growing from the inside of the spiral to the outside of the spiral, but for each segment is formed of constant circular radii. 6. wastewater activation basin according to one of the preceding An sayings, characterized in that the inflow by egg NEN robbery is provided, the spiral-like out Formation of the flow guide walls in particular as central arranged inflow cylinder in the interior of the spiral with partial lowered overflow edge realized in the jacket cylinder is. 7. Aeration tank according to one of the preceding An sayings, characterized in that along the flow  different activation zones are defined. 8. wastewater treatment tank according to claim 7, characterized records that the activation zone length, especially in the An talk about the amount of wastewater and / or the pollution of the Waste water can be varied to create flexible reactor rooms is. 9. Aeration tank according to one of the preceding claims che, characterized in that it out as a round pool forms is. 10. Process for wastewater treatment in which wastewater in a loading preferably flows into the living pool in a robbery-like manner the aeration basin preferably prop flows through the pelvic flow and the pool then leaves, characterized in that the Ab water in the basin at least essentially a spiral course follows. 11. The method according to claim 10, characterized in that the waste water from the spiral center to the outer spiral end is directed or vice versa. 12. The method according to claim 10 or claim 11, characterized ge indicates that different within the spiral Activation zones are provided, in which difference wastewater purification or activation reactions fen. 13. The method of claim 12, wherein the length and / or An Number of different activation zones depending on the load gig will be fixed. 14. The method according to claim 12 or 13, characterized in net that the activation zones by adding substances, in particular blowing air from the bottom, preferably selectable digits can be delimited.