DE19917463C2 - Three-chamber small wastewater treatment plant for batch wastewater treatment - Google Patents

Abstract

The vast majority of sewage systems are based on the flow principle. This means that they are designed for the largest wastewater flow in a certain time. DOLLAR A A disadvantage of these systems is that they are sometimes too large. That is, in the normal case a smaller plant would have been sufficient, so that the invention has set itself the task of creating an adequate plant due to the small space requirement using modified standard three-chamber pits, with simultaneous flexibility of the plant in relation to inlet fluctuations. The three-chamber pit (17) represents individual closed and olfactory containers that are not broken through by slots or pipes, the main components of which are a primary sludge and expansion tank (1), a biological part (2) and an excess sludge store (3). DOLLAR A The system is particularly suitable for rural areas.

Description

The invention relates to a three-chamber small sewage treatment plant for batch-wise biological Wastewater treatment, especially for rural areas.

Based on the fact that wastewater and its ingredients are a source for the represents environmental pollution, the high results achieved remain with the most known wastewater treatment processes fall short of expectations. The sewage End-of-the-pipe cleaning is therefore targeted by Be action measures at the place of waste water generation added. That is, is the connection not possible to a public sewage system or so expensive that the limit of If this is reasonably exceeded, such decentralized solutions from wastewater technology are available nik on. The vast majority of wastewater plants are based on the flow principle and are therefore designed for the largest inflow of wastewater in a certain time. The disadvantage here is that such systems are often designed much too large. That is, in A smaller system would normally have been sufficient.

These types of systems include, for example, septic tanks, trickling filter systems, shit trickling filter systems and activated sludge systems. Furthermore, the batch process for in industrial and domestic wastewater known where unlike flow-through plants the wastewater in portions under flow-free conditions and in a reactor the classic separation of biology and clarification in one container ter takes place. For effective cleaning in aeration plants, the separation and Ver Sealing of the biomass by sedimentation in the secondary clarifier is necessary. In some In some cases, however, the mud settles very slowly or not at all, so that none forms clear protrusion zone. The reason for these disturbances mostly lies in the mass ent winding filamentous wastewater bacteria, which leads to an increase in surface area lead mud flakes.

So is with methods and devices for the biological treatment of waste water after the DE 32 12 850 A1 discloses where waste water is present in at least one reactor in the presence of Return sludge and in a sedimentation basin downstream of the reactor, from which a sludge return line leads to the reactor is biologically cleaned. To achieve A high cleaning performance with good drainage values is provided here by the Flotation effects in the sedimentation basin and, if applicable, in the reactor  To separate swimming sludge gently with the help of a suitable device so that the gas bubbles causing the buoyancy of the floating sludge flakes are released. As a result, the divided mud flakes can sediment again, so that the active bio mass in the case of aerobic degradation via the sludge return or in the case of anaerobic degradation by sinking directly into the reactor or via the sludge return for the degradation processes preserved.

There are also liquid gassing devices and methods of operation a sewage treatment plant as known from DE 195 16 395 A1, where for aeration to waste water in a clarifier below the liquid level for the introduction of air several gas distributors are introduced. These each have a connection, optionally with a Gas source or a liquid container is connectable. This makes the gas distributors work alternately as air introduction elements or as water extraction elements having filters ment.

Solutions from trade journals are also known, such as from

• - Industry and technology
  "Mobile biological compact sewage treatment plant"
  Column 3 Correspondence sewage 1998 (45) No. 5
  Based on the size of the system described (100-2000 population equivalents), the subject matter of the invention deviates considerably from the overall order of magnitude, since the application is a small sewage treatment plant analogous to DIN 4261 Part I-IV. This means that the principle of the publication apparently relates to a biological process which does not draw off or store a separate excess sludge, so that this fact alone results in the order of magnitude of 100-2000 U (impoundment chamber).
• - VDJ Environmental Technology Coordination Center (KUT)
  "Correctly operated small wastewater treatment plants"
  Picture 1 and 2 - Environment Vol. 20 (1990)
  N ½ February
  As a result of Fig. 1 and 2 and the specified DIN standard 42, it follows that the subject of the application also belongs to the same size class. The illustration shows a fixed bed system consisting of a biological and a clarifying part, whereby fixed bed systems have another biological part as the basis (sessile microorganisms). In contrast, the plant according to the invention has freely movable microorganisms.
  A disadvantage of the published system is its susceptibility to shock loads (bathtub bumps), since the contact time of the water with the microorganisms decreases rapidly.
• - Aspects of wastewater disposal in rural areas from WASSER + BODEN 5-1988, in particular point 3.2 p. 250 (picture 1 and 2) and point 7 (picture 6)
  Figure 1 shows a classic flow method for three different interconnected concrete bodies.
  In contrast to this, the subject of the registration includes container 2 (activation) and container 3 (secondary clarification stage).
  The solution shown is therefore a flow-through system. Hydraulic loads can have a negative impact on the cleaning result.
  Regarding Figure 2: In contrast to the solution according to Figure 1, containers 2 and 3 have been combined here, although the spatial separation is still retained.
  The container technology and piping is correspondingly complicated.
  The same disadvantages as described for the system according to Figure 1 also apply here, also with regard to the necessary maintenance. For example, in the case of small revitalization systems (Figures 1, 2):
  "Taking into account the possible impact loads, the BOD _r room load B _{R is} limited to 0.2 kg / m ^3. D and the sludge load B _TS to 0.05 kg / kg. D."
  These values are clearly below the subject of the application.
  The statement (p. 250, left column, lower lines)
  "A facility for separating sludge and purified water is to be connected downstream of all biological plant particles is not applicable to the subject of the application.

Figure 6 to point 7 shows a technical system with an anaerobic swimming filter made of expanded clay, which works in the third chamber of a multi-chamber septic tank growth area is used. The system is flowed through in all parts in free flow.  

The sectors are used for pre-clarification, anaerobic fixed bed (counterflow principle) and ventilated Biology. The clarification is in the middle here. It is therefore not one commercially available three-chamber pit, but a complicated container that bad reactions to inflow fluctuations can be expected hydraulically and freight, at relatively large volume.

A general disadvantage of the described prior art is that most be Known solutions are suitable for urban, densely populated areas, but for waste water water treatment in sparsely populated areas, for example in rural areas of too much effort in terms of construction and technology, completely unsuitable are.

The invention has therefore set itself the task of a three-chamber small sewage treatment plant create, which are characterized by a small footprint using modified standard Three-chamber pits distinguish with the flexibility of the systems Inflow fluctuations, optimization and reduction of electricity consumption as well Inclusion of an inexpensive variant of the activated sludge process and the An Use of programmable logic controllers (PLC) even in small systems.

The object is achieved by the features of claim 1 and protection Subclaims resolved.

By the invention, an extremely intensive biological purification of the discharged water is achieved by treating the waste water in portions under flow-free conditions in a reactor. The classical separation of biology and clarification takes place in a container in the application according to the invention. This means that the entire clarification process has been created in a conventional modified three-chamber pit. This results in the following advantages with regard to conventional systems for sparsely populated areas:

• - Low space consumption of the entire system using standard three-chamber pits from which by modifying the water supply SBR (sequencing batch reactor) - Reactors
• - Flexibility of the systems in relation to fluctuations in the inlet (underload and overload)
• - Optimization and reduction of electricity consumption
• - Inexpensive variant of the activated sludge process  
• - PLC control of small systems using conventional control systems.

In contrast to conventional activated sludge treatment, the plant according to the invention thus has plants no separate clarifier. The clarification process is essentially through the Ge design of the control program, which normally occurs once per cycle before Clear water drain to ensure the clarification function a rest (sludge settling phase). The cleaned wastewater is then drained off. That is, in the opposite Set to the described prior art, the system according to the invention needs no tech African tools to make the microorganisms sessile. The necessary technical Equipment consists of three pumps, three float switches and a control system that by querying the floating position, cycles start or remain in the waiting position.

The invention will be explained in more detail below using an exemplary embodiment.

Show it:

Fig. 1 is a schematic representation of the system

Fig. 2 shows a filling of the biological chamber in section

Fig. 3 shows a conventional three-chamber pit with free flow

Fig. 4 shows a modified three-chamber pit

The plant consists of FIG. 1 of three main components

• - a primary sludge and expansion tank 1
• - a biological part 2
• - And a surplus sludge storage 3 .

Decisive for the total size of the container is the biological part 2 , which determines the total volume of the system with its size and is the result of a clarification calculation. In the receiving tank of the primary sludge storage 1 , the wastewater to be cleaned without preliminary treatment is collected and stored. Since the selected process is a batch process, the holding tank is designed so that a maximum amount of waste water can be collected during a treatment cycle (peak inflow). The fill level of the receiving tank is controlled by three float switches 4 , 5 , 6 with the functions start / stop feed pump 7 , maximum and overfill and continuously monitored via the control unit 8 , that is to say the clarification process is essentially determined by the design of the control program certainly.

The biological part 2 of the small wastewater treatment plant is dimensioned so that a high sludge age and aerobic sludge age as well as a low sludge load is achieved. The aim is at the same time that a sludge stabilization occurs in the dimensioning of the small sewage treatment plant (<0.05 g BOD ₅ / g TS and sludge age <20 d) in order to enable nitrogen oxidation in the basic equipment of the plant. The required oxygen is entered via commercially available ventilation plates 9 . So depending on the system, small blowers, side channel blowers or rotary blowers 10 are used under the aspect that a mini mum of energy is consumed for the oxygen input. Submersible pumps take over the mass transport. This is a clear water pump 11 and a surplus sludge pump 12 per reactor, where the clear water pump 11 advantageously on the principle of small-scale system works by anyway an impact loading is necessary in a possible seepage. In batch operation, it is beneficial for the wastewater treatment process that no negative effects from currents occur. Further, 2 of FIG. Zone by a safety 13 of the clear water region 14 from the activated sludge 15 and the activated sludge separated flakes. Since, in addition to the necessary pumps 7 , 11 , 12 and the ventilation plate 9, only the three floating switches 4 , 5 , 6 located in the primary sludge storage area are long, the technical complexity is low.

In order to solve the problem of annoying floating substances in biology 2 , the system is fed during filling until the overflow 16 responds. Problem substances then return to the receiving part 1 via the overflow 16 , the final disposal of these substances taking place with the regular evacuation of the primary and equalizing tanks.

The sludge storage 3 of the three-chamber small sewage treatment plant is used to absorb the biologically produced mass of excess microorganisms and the thickening of the excess sludge.

Basis of the three-compartment septic system according to Fig. 3 form for modifying provided commercial three chamber pit 17, the chambers of which represent individual closed containers.

That is, they are not broken through by slots or pipes and thus do not represent any flow-through spaces. Thus, according to FIG. 4, the half-section of a three-chamber pit 17 is the largest space for the biological chamber, that is, for the biological part 2, it is detached. A quarter segment is primary sludge and equalization volume 1 and the second quarter segment is the excess sludge storage 3 . The entire wastewater flow is positively controlled by pumps 7 , 11 , 12 . The only way to flow through the plant is via the inlet and then the biology to the emergency overflow. The sludge storage 3 is not affected by this. It is irrelevant which suitable materials the container is made of. It is only essential that the volumes and installation depths determined by a clarification calculation are adhered to. The control calculated and usable for each type of system is carried out via modules that can be switched on and off, using a commercially available small control system 8 . Necessary operating messages are shown by docking a display group. The processing of several analog and digital signals is also possible using the corresponding units in the small control system. In this way, further wastewater treatment goals are also possible through control programs. The following modules can be activated: nitrification, denitrification, bio-P removal, chemical P removal and UV disinfection.

reference numeral

1

Primary sludge and expansion tank

2nd

biological part

3rd

Excess sludge storage

4

Float switch

5

Float switch

6

Float switch

7

Feed pump

8th

Control unit

9

Ventilation plate

10th

Rotary lobe blower

11

Clear water pump

12th

Excess sludge pump

13

Security zone

14

Clear water area

15

Activated sludge

16

Overflow

17th

Three chamber pit

Claims (6)

1. three-chamber small wastewater treatment plant for batch-wise biological wastewater treatment using commercially available three-chamber pits, a small control system, as well as pumps and ventilation devices, characterized in that the three-chamber pit ( 17 ) represents individual closed and non-flowed tanks, the main components of which are a primary sludge and expansion tank ( 1 ), a biological part ( 2 ) and an excess sludge storage ( 3 ), the total size of the plant being determined by the container of the biological part ( 2 ) and the entire plant, its technical part, i.e. its waste water flow (inlet and outlet) consists of pumps ( 7 ; 11 ; 12 ), float switches ( 4 ; 5 ; 6 ) and aeration plate ( 9 ), is positively controlled according to a control program via modules, so that usually once a cycle before a clear water drain to ensure the clarification function Rest (sludge settling phase) is provided by querying the Sc hwimmer positions of the float switches ( 4 ; 5 ; 6 ) either a new cycle is started or the system remains in the waiting position, during which it is fed until an overflow ( 16 ) responds in order to convey floating and problematic substances back into the receiving part ( 1 ) for disposal and the wastewater flow via pumps is also program-controlled, so that it is the only way to flow through the system via the inlet and the following via the biological part ( 2 ) to the emergency overflow, except for the sludge storage ( 3 ). 2. Three-chamber small wastewater treatment plant according to claim 1, characterized in that a half section of a three-chamber pit ( 17 ) for the biological part ( 2 ) is converted so that a quarter segment represents the primary sludge and compensation volume ( 1 ), the second quarter segment represents the excess sludge storage ( 3 ) . 3. three-chamber small sewage treatment plant according to claim 1 or 2, characterized in that the receiving tank of the primary sludge tank ( 1 ) of the waste water to be cleaned is designed so that it allows a peak inflow by three float switches ( 4 ; 5 ; 6 ) with the functions start / Stop with a feed pump ( 7 ) coupled to it, the maximum of the inflow and overfill constantly controlled by a control unit ( 8 ). 4. three-chamber small sewage treatment plant according to claim 1, characterized in that the biological part ( 2 ) is dimensioned so that a sludge stabilization at <0.05 g BOD ₅ / g TS and a sludge age <20 d arises by the required oxygen via aeration plate ( 9 ) via, for example, a rotary lobe blower ( 10 ) and submersible pumps such as clear water pump ( 11 ) and excess sludge pump ( 12 ) take over the oxygen transport, with a safety zone ( 13 ) delimiting the clear water area ( 14 ) from the activated sludge ( 15 ). 5. Three-chamber small wastewater treatment plant according to claim 1, characterized in that a sludge storage ( 3 ) serves to receive the biologically produced mass of excess microorganisms and the thickening of the excess sludge. 6. Three-chamber small sewage treatment plant characterized according to the preceding claims net that the control of a small control system can be switched on and off the basis of the clarification-technical calculations of volume and installation depth to be observed fen takes place, so that the entire clarification process exclusively by the respective Control program is carried out.