WO2000051421A2

WO2000051421A2 - Method for delivering and cleaning salt water in a fish rearing installation

Info

Publication number: WO2000051421A2
Application number: PCT/DE2000/000644
Authority: WO
Inventors: Martin Sander
Original assignee: Erwin Sander Elektroapparatebau Gmbh
Priority date: 1999-03-03
Filing date: 2000-03-03
Publication date: 2000-09-08
Also published as: DE19909172A1; DE19909172C2; AU4098900A; WO2000051421A3

Abstract

The invention relates to a method for delivering and cleaning salt water, especially in a fish rearing installation having at least one fish basin (22) and a cleaning system (1, 20, 25) provided outside of said basin. The inventive method is characterized by the following steps: a) draining the water from the at least one fish basin (22) while feeding it to a hydrocyclone or sedimentation basin (20) for a rough separation of the solid and suspended matter; b) feeding the water into an admission chamber (2) provided in the lower area of a floatation tower (1); c) introducing air bubbles into the admission chamber (2) of the floatation tower (1) and delivering the water containing the ascending air bubbles from the admission chamber (2) to a reaction chamber (7) situated in the area of the floatation tower (1) located thereabove; d) draining the water out of the lower area of the reaction chamber (7) into the lower area of a biofilter (25); e) returning the water from the upper area of the biofilter (25) into at least on fish basin (22), whereby; f) the water is delivered in a closed circuit and the only supply of energy for operating the system in the floatation tower (1) is provided by the introduction of air bubbles into the water.

Description

Process for conveying and purifying salt water in a fish farming system

It is known to raise fish in breeding tanks and to sell them for consumption when they reach a certain size. Freshwater fish can be kept in ponds with a natural or artificial water inlet and a water outlet. By supplying the fresh water, the impurities in the water caused by excrement and feed residues are removed and oxygen is also added to the water.

In the field of aquarium technology, it is known to provide internal filters for water treatment. DE 28 11 943 AI discloses an internal aquarium filter which is supplemented by a flotation reactor for use in a saltwater aquarium. The filtering takes place via candle filters, through which the water can flow in from the outside. The flotation reactor and the candle filter are connected to each other via a bottom chamber. An outflow is provided in the flotation reactor, through which finely bubbled air is introduced. Part of the water flowing into the bottom chamber of the flotation reactor is conveyed into the reaction chamber of the flotation reactor by the rising air bubbles. Another filter element is provided with a pipe which partially projects above the water surface. A further air vent is arranged in this filter element. The water rising in this filter element with the air bubbles is conveyed into the pipe and returned to the aquarium. Since the cleaning takes place inside the aquarium basin, the water can only flow through the introduced air, because only the internal resistance of the filter elements has to be overcome.

If seawater fish are to be reared in a fish farm, this must either be built near the coast fresh sea water can be supplied to the fish tank, or a cleaning system must be provided to treat the water. In saltwater aquariums, it is known to pump the water out of the aquarium tank and lead it into a hydrocyclone, from there to pump into a flotation tower, where foam is formed. For this purpose, water is sucked out of the reaction chamber of the flotation tower by means of an injector pump, then mixed with air in a very fine particle shape and fed back to the reactor. The fine-bubbled air makes contact with the protein compounds and dirt particles in the water. The air bubbles rising upward then convey these protein compounds and dirt particles into a foam collection space arranged above the reaction space, which opens into the foam tube running upwards. Via the foam collection tube and the foam tube, the proteins and dirt particles reach a foam collection container, from where they can then be supplied to the waste water or otherwise disposed of. A flotation tower described is known for example from DE 44 16 587 Cl or DE 36 43 931 AI. The cleaned water is sucked out of the flotation tower by a pump, possibly fed to further filter systems and pumped back from there back into the aquarium tank.

A disadvantage of the described method is that the pumps required to convey the water not only require a not inconsiderable amount of energy, but are also susceptible to failure and repair as a result of contact with the salt water. The operating costs of such a system are therefore quite high.

This disadvantage can be accepted for the breeding and / or presentation of rare or exotic marine fish. However, this method is so uneconomical for the breeding of conventional marine fish occurring in our latitudes, which are then to be marketed as edible fish, that the fish is exposed in the wild. would be unsaleable. The rearing of seawater edible fish has therefore so far not been able to prevail.

Starting from this problem, a method for conveying and cleaning salt water, in particular in a fish rearing system with at least one fish tank and a cleaning device provided outside of it, is to be specified which can be operated economically.

The problem is solved through the following steps:

a) draining the water from the at least one fish tank into a hydrocyclone or a sedimentation tank for the rough separation of the solid and suspended matter from the water,

b) feeding the water into an inlet space provided in the lower region of a flotation tower,

c) introducing air bubbles into the inflow space of the flotation tower and conveying the water with the rising air bubbles from the inflow space into a reaction space in the area of the flotation tower above,

d) draining the water from the lower region of the reaction space into the lower region of a biofilter,

e) returning the water from the upper area of the biofilter to the at least one fish tank, whereby

f) the water is conveyed in a closed circuit and the only energy supply for operating the system in the flotation tower is through the introduction of the air bubbles into the water. This process completely eliminates the need for conventional, expensive and energy-consuming water pumps. The core element of the seawater treatment plant is the flotation tower, in which the water is cleaned by the entry of the air bubbles. The principle is used here that the air bubbles introduced into the lower part of a container carry the water into which they are introduced with them as they rise to the surface of the water, that is, they convey them upwards. In practice it has been shown that a pressure difference of only 6 to 20 cm water column between the water introduced into the flotation tower and the water discharged from it is sufficient to operate the entire cleaning system in a closed circuit.

The air bubbles are preferably introduced via outlets arranged in vertical tubes, the tubes connecting the reaction space and the inlet space to one another. A further outflow can be provided between the tubes, via which ozone is introduced into the flotation tower. Ozone is not necessary to operate the system. But it can be used to maintain biological balance.

The energy requirement is reduced by a factor of 5 to 10 compared to conventional systems using the method according to the invention.

A flotation tower for use in the process according to the invention, with a housing, an inlet space, a reaction space arranged above it and a foam collection space arranged above it, which is connected to the reaction space via a foam tube, air bubbles being introduced into the reaction space for the water to form foam , is characterized in that the housing is closed and the inlet space is provided, which is connected to the reaction space via a plurality of vertically arranged pipes, that a for generating the air bubbles The outflow seen in each tube is arranged such that the water can be introduced into the inlet space and can be removed from the reaction space, and that the water outlet is preferably provided in the lower region of the reaction space.

Through this design, the fine-bubbled air bubbles introduced into the water in the feed space, which are introduced from the feed space via the pipes into the reaction space, promote the water in the feed space upward into the reaction space, where the foam which forms on the water surface can be skimmed off. Due to the several vertically arranged pipes for connecting the inlet chamber to the reaction chamber, the mixing of the water with fine-bubbled air is better and the volume flow conveyed upwards is more uniform.

For this purpose, it is particularly advantageous if six tubes are provided which are regularly distributed over a circle.

The reaction space and the inlet space are separated by an inserted plate which has holes for inserting the tubes in accordance with the number of tubes used. If the plate is thick enough, the centering of the tubes when inserting them into the plate is considerably simplified.

It is particularly advantageous if the outlets can be removed upward from the pipes via the lines connected to them. This enables a quick exchange. For this purpose, the air lines are screwed to the housing of the flotation tower. An embodiment of the invention will be explained in more detail below with the aid of a drawing. It shows:

Figure 1 - the schematic longitudinal section through a flotation tower;

Figure 2 - a detail of Figure 1;

Figure 3 - another detail of Figure 1;

Figure 4 - the schematic representation of a fish farm operated according to the inventive method;

Figure 5 - a plan view of a fish farm according to

Figure 4 in a simplified representation.

The fish farming system consists of a plurality of fish basins 22, which are connected to one another via outlet pipes 28 and inlet pipes 29. The fish tanks 22 are filled with salt water or sea water. Water is fed from a fish tank 22 to a hydrocyclone 20 via a line 21. In the filled hydrocyclone 20, solids and suspended matter are roughly separated. In a drain line 23 provided below the inlet in the hydrocyclone 20, the water is fed to the inlet space 2 of a flotation tower 1. Via an outlet 16, which is provided above the inlet chamber 2, the water from the flotation tower 1 is fed to a biofilter 25, where the finest solids and suspended matter are collected in a sludge collecting chamber and discharged into the sewage network via a line 24. Via an outlet 26 provided in the upper region of the biofilter 25 which is completely filled with water, the cleaned and oxygenated water is fed into the inlet pipe 29 and from there fed back to the fish tank 22. Instead of a hydrocyclone, a conventional sedimentation basin in a rectangular or round shape can be used. The water is cleaned and pumped in a closed circuit, with no pumps being provided for pumping. The energy required to convey the salt water is supplied exclusively in the flotation tower 1 by the air bubbles introduced into the water.

Figure 1 shows the flotation tower 1 in a schematic longitudinal section. The flotation tower 1 consists of the cylindrical housing la. A reaction chamber 7 and an inlet chamber 2 are formed in the housing 1a. The inlet chamber 2 and the reaction chamber 7 are separated from one another via a plate 4 provided with holes 4a, which is inserted into the housing 1a. The reaction space 7 is closed off at the top by a plate 9 to which a foam pot 12 is connected. A foam tube 11 is provided in the foam pot 12 and is connected to the reaction space 7. The foam pot 12 is connected to the environment via an exhaust air duct 13. In the holes 4a of the plate 4, vertical tubes 6 are inserted, which connect the inlet space 2 with the reaction space 7. An outlet 5 is arranged in each tube 6 and is connected via a line 8 to a compressed air source. Via the outflow 5, the compressed air is introduced in a finely divided manner into the water that has entered the inlet space 2 via the inlet 3. The flotation tower 1 is filled with water up to the plate 9.

The air bubbles formed in the tubes 6 and rising into the reaction chamber 7 convey the water in the inlet chamber 2 upwards, so that new water can be fed continuously to the inlet chamber 2 via the inlet 3. The foam which forms in the reaction space 7 is passed via the foam tube 11 into the foam collecting container, from where it is disposed of. The lines 8 are fastened in the plate 9 via a screw connection 10. By loosening the screw connection 10, the outlets 5 on the lines 8 can be pulled up out of the flotation tower 1.

This configuration makes it possible to change the outflow without the water from the flotation tower 1 being removed. must be left. The maintenance costs are therefore significantly reduced. A standpipe 15 connected to the inlet space 2 and a standpipe 14 connected to the reaction space 7 show the pressure difference between the outlet 16 arranged in the lower region of the reaction space 7. The suction side is separated from the pressure side by the plate 4 in the flotation tower 1. In a practical embodiment, the plate 4 has a diameter of 600 mm and a thickness of 12 mm. There are six holes with a pitch circle diameter of 300 mm. The pressure difference between the suction side (inlet space 2) and the pressure side (reaction space 7) is 6 to 20 cm water column.

In practice, it has been shown that a pressure difference of 6 cm water column is already sufficient to operate the system in a closed circuit.

Between the tubes 6 in the flotation tower 1, an outflow, not shown here, can be provided, via which ozone is introduced into the flotation tower in a very fine manner. This outflow is also arranged such that it can be pulled up out of the flotation tower 1 via the line connected to it.

Reference list

1 flotation tower la housing

2 inflow rooms

3 inflow

4 plate

4a holes

5 vents

6 pipe

7 reaction space

8 line

9 plate

10 screw connection

11 foam tube

12 foam pot / foam collecting space

13 exhaust duct

14 standpipe

15 standpipe

16 process

20 hydrocyclone / sedimentation basin

21 line

22 fish tanks

23 drain pipe

24 line

25 biofilters

26 procedure

27 sludge collector

28 drain pipes

29 inlet pipes

Claims

claims

1. A method for conveying and cleaning salt water, in particular in a fish rearing system with at least one fish tank (22) and a cleaning device (1, 20, 25) provided outside it, characterized by the following steps:

a) draining the water from the at least one fish tank (22) into a hydrocyclone or a

Sedimentation basin (20) for coarse separation of solid and suspended matter,

b) supplying the water to an inlet space provided in the lower region of a flotation tower (1)

(2),

c) introducing air bubbles into the inlet space (2) of the flotation tower (1) and conveying the water with the rising air bubbles from the inlet space (2) into a reaction space (7) in the area of the flotation tower (1) above,

d) draining the water from the lower region of the reaction chamber (7) into the lower region of a

Biofilters (25),

e) returning the water from the upper region of the biofilter (25) into the at least one fish tank (22), wherein

f) the water is conveyed in a closed circuit and the only energy supply for operating the system in the flotation tower (1) is by introducing the air bubbles into the water.

2. The method according to claim 1, characterized in that the air bubbles are introduced via outlets (5) arranged in vertical tubes (6).

3. The method according to claim 1, characterized in that ozone is introduced into the flotation tower (1).

4. Flotation tower for use in the method according to claim 1 or 2, with a housing (la), an inlet space (2), a reaction space (7) arranged above it and a foam collection space (12) arranged above it, which via a foam tube ( 11) is connected to the reaction chamber (7), air bubbles for foaming the water being able to be introduced into the reaction chamber (7), characterized in that the housing (la) is closed and the inlet chamber (2) via a plurality of vertically arranged pipes (6) is connected to the reaction chamber (7) in that an outflow (5) provided for generating the air bubbles is arranged in each tube (6) so that the water in the

Inlet space (2) can be introduced and can be discharged from the reaction space (7), and that the water outlet (16) is provided in the lower region of the reaction space (7).

5. Flotation tower according to claim 4, characterized in that six tubes (6) arranged regularly distributed on a circle are used.

6. flotation tower according to claim 4, characterized in that the separation of the reaction chamber (7) and inlet chamber (2) by an inserted plate (4), which has holes (4a) for inserting the tubes (6).

7. flotation tower according to claim 4, characterized in that the outflow (5) via the associated with them

Lines (8) can be removed upwards from the tubes (6). Flotation tower according to claim 4, characterized in that an outflow for the introduction of ozone is provided between the tubes (6).