DE3423226A1 - Plant for the biological purification of waste water - Google Patents

Abstract

The invention relates to a plant for the biological purification of waste water, which is composed of sequentially arranged filter tanks which are occupied by plants having an intensive root system, and a calming tank connected upstream of the filter tank. In order to improve the efficiency of such a plant, according to the invention it is proposed to design the calming tank as a mechanical settling stage (1), that the first filter stage connected thereto is composed of at least one tank (2, 3) filled with loamy sand, sand and gravel and planted with reeds and through which flows vertically, over its entire width and length, intermittently supplied waste water, that following the first filter stage is a second filter stage which is composed of a tank (4, 5) filled with sand and gravel planted with reeds and through which waste water flows horizontally over its entire width and depth, that downstream of the second filter stage is an elimination stage which is composed of at least one tank (6, 7) filled with gravel, planted with rushes and through which waste water flows horizontally over its entire width and depth and that, following this elimination stage, is an adsorption stage which is composed of at least one tank (8, 9) filled with loamy sand and planted with reeds and through which water flows horizontally over its entire width and depth. <IMAGE>

Description

Plant for the biological treatment of wastewater

The invention relates to a system for the biological purification of Wastewater according to the preamble of claim 1.

From DE-AS 21 63 283 such a system is known in which after a calming basin, two parallel-connected, alternately exposed to wastewater Filter beds are provided.

Underneath the filter material drainage pipes are arranged so that periodic drainage is possible. The filtered water becomes one with Overgrown plants are fed to the elimination stage, with only the root space below the bed surface is flowed through.

The object of the present invention is to provide a system of the above mentioned type in such a way that by observing certain conditions the mode of operation can be improved.

This object is achieved according to the invention by means of the characteristics of claim 1 specified features.

Preferably further developments result from the subclaims.

The system according to the invention is described below with reference to the drawings explained.

It shows: FIG. 1 a schematic plan view of an installation and FIG. 2 shows a partial longitudinal section (schematic). The system consists of a mechanical one Settling stage, a filter stage, the elimination stage (s) and an absorption stage. The system components are described individually below using exemplary embodiments.

Mechanical stage A single-chamber septic tank from 1400 is planned 1 content.

The sludge removal (approx. 400 l) takes place annually from the bottom of the pit silver, a pressure line to the flowerbeds of the plant complex. The inflow takes place via a gravity pipe, the drain to the plant system via a lifter.

There is a height difference of 10 cm between the inlet and outlet. The lift of the jack should be 25 cm and therefore approx. Feed 200 l (50 mm) intermittently to the plant area.

Filter stage The filter stage is alternately charged via a lifter and flows through vertically. The suspended solids contained in the sewage are here retained on the surface. The root formation of the reeds and the movement of the Straws ensure that the filter is kept open.

The filter consists of a 10 cm thick cover layer of medium loamy sand 513, a 50 cm coarse sand layer (2 1.2 - 1.8 mm) and a drainage layer Gravel (# 6 - 12 mm) 30 cm thick from which the filtrate is discharged via a drainage pipe will.

If in winter with massive frost the vertical filtration by freezing over If the surface comes to a standstill, the subsequent ones are fed directly reed basins flowed through horizontally by slide control.

Elimination stage - reeds The reed beds following the filter stage are flowed through horizontally. The soil body consists of a 90 cm thick large-pored material, coarse gravel ~ 6 - 12 mm or expanded clay.

The soil enters the soil through the distribution channel Hochlochklinker and a gauze.

The water level in the pool is determined by the height of the overflow, it should not reach the soil surface and preferably about 5 cm below the On the surface of the floor - this applies to all pools with horizontal flow.

Elimination stage - rushes The following rush basins are horizontal flows through. The thickness of the soil must be adapted to the depth of the roots and should not exceed 50 cm.

The soil consists of homogeneous, large-pored material, coarse gravel ~ 6 - 12 mm.

Adsorption stage - reeds The last stage is a horizontal flow A reed basin, the bottom of which consists of a 90 cm thick, fine-pored, clayey Material.

Due to the exchange capacity of the soil, as with conventional Land treatment methods Phosphorus and nitrogen bound. A reduction in this Nutrients can also be expected outside of the growing season.

The formation of roots in the reeds ensures sufficient permeability of the soil body, which has a filter speed of 7.7.1O-6m / s (at Q max = 1001 / h) Has. This last stage in itself can be a so-called fining pond or oxidation pond still be downstream. The oxidation pond has a 3rd in the open water area a surface of 16.7 m² 2 volume of 10.6 m and a surface of 16.7 m The slope incline is 1: 1. The subsequent shallow water area has a bottom slope of 1: 5, a volume of 3.4 m3 and a surface of 13.5 m2.

The seal is made by means of a 20 cm thick pile of clay.

The inlet is 50 cm below the surface of the mirror in the open water area. The summer run is at the end of the shallow water zone. In winter becomes a Inlet, which is arranged 30 cm below the surface in the open water zone, through Valve control started up as soon as there was an ice cover on the pond 10-15 cm. The layer of air under the ice isolates the deeper one Water surface and protects against further freezing of the pond.

With the creation of a fining pond, the quality of the process can be significantly improved. In addition to denitrification, further phosphorus elimination, , Oxygen enrichment, reduction of the number of germs and the residual BOD5, fulfills the Another important function of the pond in summer is its buffering effect. By the high evaporation of the marsh plants increase conductivity and the concentrations of the wastewater parameters in the flow of the plant basins. At night and when precipitation begins, increased concentrations are flushed out and diluted in the pond.

Planting Suitable plants are known from the prior art.

In addition to the physiological properties, it is important to make the selection the development of the root system, the dominance and reproduction of the plant. It is advisable to adjust the depth of the pelvis to the depth of the roots, otherwise different reaction and flow zones can arise. Rushes and reeds multiply very quickly in nutrient-rich locations. Reed loses in the process in strength and is susceptible to attack by pests, especially aphids. The plant stocks, especially in the case of small plants, are affected by the wind endangered. The location must therefore be sheltered from the wind and have maximum sun exposure allow.

The pond should be planted with reeds (phragmites australis), rushes (Schoenplectus lacustris) can be followed by the following macrophytes to be planted.

Operation of the plant sludge treatment The accumulating in the sewage treatment plant Sludge can, provided it is stabilized, on dry beds planted with reeds be applied. The mud will quickly drained and mineralized, the quality of the drainage process is also improved.

The composting of the dried sludge causes the reed to become rhizomes inactive and the use for soil improvement in agriculture and gardening possible.

Once a year approx. 400 liters of sludge from the septic tank are transferred to the upper flat of the reedbed of the adsorption stage aurgebracllt. After the process recommends it is worth pumping back the drain of the basin, which is polluted with filtrate, into the inflow of the system. A deduction in summer ensures rapid mineralization of the sludge. by after completion of the sludge extraction, the pipe must go through a provided drinking water connection be rinsed.

Plant water requirement and evapotranspiration The stalk density was (2 years after planting) with reeds (Phragmites australis) 1000 pieces / m2 and with Rushes (Schoenoplectus lacustria) 2770 pieces / m2 and thus reaches 10 times as much the natural condition.

A stalk density of Reeds of 500 hslme / m2 and rushes of 1000 stalks / m2 can be assumed.

Winter operation The distribution channels for the plant basins receive a heat insulating cover.

The horizontally flowed plant basins remain with sufficient hydraulic load, like the practice in Bad Reichenhall and in occupied the Austrian Alps.

When there is severe frost, the surface of the vertical flow freezes over Ceilings to be expected.

A shutdown of these basins and a direct introduction into the horizontally flowed through basin is therefore provided.

In the event of insufficient hydraulic loading, the flatter ones can be used Rush basins with an insulating layer of straw or with the clippings from the basin to be covered.

The fining pond becomes 30 cm with an ice cover of 10 - 15 cm lowered and through the layer of air between the water and the ice cover from further freezing over protected.

The pond thus remains functional even in winter.

Claims (7)

Claims 1. Plant for the biological purification of wastewater, consisting of filter basins arranged one behind the other with a strong root system having plants are occupied, as well as with an upstream of the filter tank Calming pool, characterized by the fact that the calming pool is mechanical Deposition stage (1) is designed that the subsequent first filter stage of at least one with loamy sand, sand and gravel-filled and planted with reeds along its entire width and length vertically from intermittently fed wastewater flow through the basin (2,3) consists in that the first filter stage has a second filter stage, those filled with sand and gravel, planted with reeds over their entire width and depth horizontally traversed by the sewage basin (4,5) consists that the second Filter stage is followed by a #. Elimination stage, which consists of at least one filled with gravel, planted with rushes on all its width and depth horizontally there is a basin (6,7) through which the sewage flows and that this elimination stage an adsorption stage follows, consisting of at least one filled with loamy sand and reeds planted on all its breadth and depth horizontally from the water flowed through basin (8,9) consists. 2. Plant according to claim 1, characterized in that the basin of all steps have a dimension ratio width to length of 1: 1 or 1 2. 3. Plant according to claims 1 and 2, characterized in that the adsorption stage is followed by a fining pond. 4. Installation according to one of the preceding claims 1 to 3, d a d u r o h g e k e n n n z e i c h n e t that for all basins of the second and following Filter level in each case at the water level slightly below the soil surface holding top is provided. 5. Installation according to one of claims 1 to 3, d a d u r c h g e k e n n z e i c h n e t that for the vertically flowed through basins of the first filter stage a device holding the water level at a maximum of half the depth of the Filterkörperar is provided. 6. Installation according to one of claims 1 to 4, d a d u r c h g e k e It is noted that the front walls of the horizontally flow-through basins are made of perforated stones or perforated walls are formed. 7. Plant according to claims 1 to 6, characterized in that the gravel size is 6 to 12 mm and the sand grain size is 1.2 to 1.8 mm.