DE102018128600B4 - Filter device and cleaning system - Google Patents

Abstract

Filter device (1) for filtering algae, microorganisms and the like from water, comprising- an inlet (4), - a filter space (2) to which water can be fed via the inlet (4), - a filter membrane (5) for filtering out Algae, microorganisms and the like, - a drain (6) for the filtered water below the filter membrane (5), - a gassing device (7) for supplying a gas to the filter membrane (5), which is between the drain (6) and the filter membrane (5). is arranged, - an agitator (8) for mixing the water in the filter room (2) and - a discharge device (9) for discharging foam (10) or impurities on the surface (O) of the water in the filter room (2).

Description

The invention relates to a filter device for filtering algae, microorganisms and the like from water and a cleaning system constructed therefrom.

In addition to the actual flora and fauna, all saline oceans and freshwater also contain microorganisms such as algae, microorganisms, bacteria and the like. The microorganisms contained in the world's oceans alone represent a biomass with a practically inexhaustible supply, which also constantly grows back. A so-called algae bloom often occurs, particularly in warmed and essentially still waters. This means that the number of algae and microorganisms, for example in g/m ³ , exceeds a certain value, so that the water becomes depleted of oxygen and fish, for example, suffocate.

To avoid this, it is known that the algae are filtered out of the water. This can be done, among other things, by adding precipitants, but this is hardly feasible for practical and ecological reasons. Furthermore, it is known to filter algae out of the water mechanically using devices, for example filters, or to separate them, for example, by means of centrifuges or by adsorption or by dissolved air flotation. Such filter devices can also be designed to float so that they can be used on a mobile basis.

The filter devices usually have a filter chamber to which water is supplied via an inlet, as well as a filter membrane for filtering out the algae and an outlet downstream of the filter membrane in order to remove the purified water again.

From the DE 10 2012 207 731 A1 is a device for the pre-cleaning of sea water in particular known with a filter room, an inlet for water, an outlet for purified water, a gassing device and a discharge device for discharging contaminants. However, the filter room is preceded by an additional flocculation tank for flocculation.

However, the problem that often arises is that the filter membrane is clogged with a filter cake that has to be removed mechanically in order to regain the desired filter performance. This can hardly be avoided even with an additional agitator in the filter room.

It is also known to either foam and skim the algae or microorganisms or to design the filter device in the manner of a settling tank. However, only small throughput volumes are achieved here.

The invention is based on the object of developing a filter device for algae in such a way that it can be operated in a simple manner and has a high level of efficiency. Furthermore, a cleaning system constructed from this should be specified.

According to the invention the object is achieved by a filter device with the features of claim 1. With such a filter device, a cleaning system according to the invention can also be constructed according to claim 6.

The core idea of the invention is that the device for filtering algae, microorganisms and the like comprises a filter space to which the water to be filtered can be fed via an inlet. In the filter room, a filter membrane for filtering out algae, microorganisms and the like is arranged, in particular on the bottom side. Furthermore, a drain for the filtered water is provided below the filter membrane. To keep the filter membrane clean, a gassing device is used to supply a gas to the filter membrane in countercurrent to the water, which is arranged below the filter membrane. Furthermore, an agitator is provided in the filter room to keep the water circulating in the filter room. Finally, there is a discharge device in the filter room for discharging impurities on the surface of the water in the filter room.

The filter space, which is formed, for example, by a housing made of metal, in particular stainless steel, creates a delimited space in which an increasing concentration of algae is maintained through a constant supply of water. The filter space is, for example, cubic in shape, but it can also have any other shape. The area of the filter membrane or a filter is preferably chosen to be so large that resistance due to the pressure loss during filtering out is minimized. The water flows into the filter room via one or more inlets in a flow direction, for example from top to bottom. Algae, microorganisms and the like are filtered out on the bottom filter or the filter membrane and the purified water exits the filter room again via a drain that is arranged behind the filter membrane in the direction of flow.

In order to avoid clogging of the filter membrane, it is gassed in countercurrent. For this purpose, a gassing device is arranged between the drain and the filter membrane, for example Blow ambient air into the filter room from bottom to top. The rising gas bubbles penetrate the filter membrane and remove residues, especially on the top. In addition, the injected gas causes the filtrate to foam. The amount of gas, the gas pressure and the flow speed of the water are coordinated in such a way that optimal filter performance is achieved. In particular, the flow velocities and volume flows are selected such that the rising gas bubbles are not torn away downwards by the water flow.

In principle, such gassing can also be carried out using air nozzles that are distributed throughout the interior of the filter chamber in order to keep the surface of the filter membrane clean.

Furthermore, an agitator, also called a disperser, is provided in the filter room, which can be designed in any way and is also made of metal/stainless steel, for example, in order to maintain circulation of the water in the filter room and to prevent foam formation on the surface of the water support financially. For example, several paddle-shaped and possibly aerodynamically shaped sheets can be rotatably mounted via a linkage. The agitator also generates a current parallel to the filter membrane in order to also minimize clogging.

Finally, the foamed algae on the surface of the water are removed from the filter room using a discharge device and collected. The discharge device can, for example, be a fixed component in the form of a flow guide plate. Due to the rotary movement of the agitator and the cross flow generated in a cleaning system composed of several filter devices, the foam floating on the surface of the water is also set in rotation and can be automatically skimmed off with a suitably arranged and shaped flow guide plate and fed to further recycling via a separate outlet . This flow guide plate can also be designed to be height-adjustable, for example by means of screws on one or more vertically arranged perforated rails, in order to achieve an optimal discharge result. Alternatively or additionally, the discharge device can also include a movable slide, that is to say a linearly movable or rotating slide or the like, which, through its movement, skims off the foam floating on the surface of the water.

The filter room can, for example, have a volume of 375 m ³ with a filter area of 125 m ² . The filter membrane has a pore size or mesh size of, for example, a maximum of 20 μm, in particular a maximum of 10 μm.

With the filter device, algae in particular are filtered out of the water, collected and concentrated. The algae or the filtrate can then be used for further purposes. For example, they are composted and used as fertilizer. They can also be used to produce biogas or other fuels. It is also possible to reuse the contained protein and other nutrients for food production.

Such a filter device can be designed to be stationary in order to also serve as a wastewater treatment system. It can also be designed to be mobile, that is, mounted on or in a vehicle. In particular, it can be installed in a ship such as a motor or sailing ship or a barge, which is equipped with a preferably movable funnel to collect seawater and supply it to the filter device. Likewise, the filter device can be set up in a stationary manner at a location with high flow speed in a body of water, with appropriate inlet and outlet channels being provided. The flow can be dictated by tides and/or geological conditions. Preferably, the water, whether in mobile or stationary operation, is first passed through a turbine to generate energy and then fed to the actual filter device. This means that a significant portion of the energy required for operation can be obtained.

The subclaims represent advantageous embodiments of the invention.

In a first embodiment, a frother is assigned to the inlet or inlets, which already swirls the incoming water in order to improve the foam formation. The frother can either be designed as a static component or also movable, for example according to the functional principle of a whisk.

All filters or sieves known to those skilled in the art can be used as the filter membrane, for example a fine-meshed metal grid. In particular, it is proposed that the filter membrane or the filter is made of ceramic. For example, the filter membrane is formed by a ceramic membrane. This can be manufactured with the mesh size described above and has sufficient strength and durability, for example towards sea water. Their surface is preferably hydrophobic and/or equipped with the lotus effect in order to prevent the accumulation of residues. A mass exchange between the water and the blown-in air can also be supported.

Furthermore, baffles can be arranged at the inlet and outlet as well as in the filter room at desired positions with the desired size and shape in order to direct the water to be filtered in the preferred quantity and flow rate. The baffles are rigidly arranged or designed to be movable, for example to adapt to different volume flows.

Preferably, the water flowing into the filter device is guided through one or in particular two symmetrically arranged inlets in such a way that cross-flow or semi-cross-flow filtration takes place. In particular, if, as described below, several filter devices, each with the same filter area, are connected or arranged one after the other, so to speak, the incoming volume flow is gradually reduced in each successive filter device, while the total water flow emerging from all filter devices or an entire cleaning system remains constant. Since decreasing volume flows flow into the filter devices arranged one after the other, different, decreasing concentrations of the filtrate are then present in the filter devices. Conventional cleaning processes such as flotation and dispersion are therefore combined with simultaneous cross-flow or semi-cross-flow filtration.

A water purification system can be built from such a filter device. Seen in the direction of flow, several filter devices with essentially the same structure are arranged one behind the other. The flow conditions are preferably selected such that a smaller volume flow enters each successive filter device, in particular with the same flow speed. Cross-flow or semi-cross-flow filtration can thus be obtained. This means that with a compact design of the entire cleaning system, an optimal filter result with, for example, maximum algae yield can be achieved. In principle, the filter devices can also be arranged as a square or rectangle. It can be seen that, for example, a central supply line is provided, from which the water to be cleaned is supplied to the individual filter devices via pipes. The respective processes for the purified water can also be combined into a central process.

It can be seen that all components of the filter device are centrally controlled, for example in order to be able to adjust the throughput of water and gas as well as all functionalities. Valves, flow meters, sensors and the like are provided for this purpose.

The invention has been described above essentially in connection with the filtering of seawater, but it can be seen that the filter device or cleaning system can also be used in other areas of technology.

It is understood that the features mentioned above and to be explained below can be used not only in the combination specified in each case, but also in other combinations. The scope of the invention is defined only by the claims.

• 1 eine Filtervorrichtung in schematischer Darstellung und
• 2 eine zusammengesetzte Reinigungsanlage.

The invention is explained in more detail below using an exemplary embodiment with reference to the associated drawing. The figures in the drawing show:

• 1 a filter device in a schematic representation and
• 2 a composite cleaning system.

In the 1 A filter device 1 is shown purely schematically in cross section. It has a filter chamber 2, which is formed, for example, by a housing 3 made of stainless steel. Water flows into the filter room 2 via an inlet 4 in the direction of flow according to the arrow S and leaves it again via an outlet 6 on the underside of the filter room 2.

A filter membrane 5 is used to clean the water, in particular from algae, microorganisms and the like, which is designed, for example, as a metal grid or as a ceramic membrane or filter and, for example, has a hydrophobic and/or lotus effect surface.

Viewed in the flow direction according to the arrow S, a gassing device 7 is arranged below the filter membrane 5, for example a perforated pipe network supplied with compressed air, which is only indicated schematically here. The emerging gas flows upwards in the opposite direction according to arrow G and passes through the filter membrane 5. This removes residues on the filter membrane 5 and thus prevents them from clogging.

Furthermore, an agitator 8 is provided, which, as indicated by the double arrow D, can be driven in a rotatable manner. The agitator 8 is used to mix the water in the filter chamber 2. The agitator 8 includes, for example, a few paddles which are rotatably mounted on a frame in order to generate a flow parallel to the filter membrane 5, so that their clogging or clogging is reduced.

A foam 10 forms on the surface O of the water, which consists of foamed algae and is indicated here schematically with wavy lines. The foam 10 is discharged from the filter chamber 2 by a discharge device 9, here a slide that can be moved linearly according to the arrow L, and is preferably collected. The foam 10 floating on the surface O of the water is skimmed off with the slide, which can be moved linearly according to the arrow L. The discharge device 9 can also be designed in a simple manner as a particularly height-adjustable flow guide plate, which automatically skims off the foam 10 floating on the surface O of the water and rotating with the water and, for example, feeds it to a separate outlet for further use.

Due to the combination of filtration on the filter membrane 5 and foaming by the rising gas and by the agitator 8, for example, the algae concentration increases steadily with increasing amount of filtered water in the foam 10 until it has reached a desired value. The foam 10 can then, for example, be composted or further processed into fuels, food or other end products.

In 2 A cleaning system 11 is also shown purely schematically, which is composed of four filter devices 1, the filter devices 1 only being shown in simplified form as a block. From the flow direction of the water according to the arrow S it can be seen that all four filter devices 1 are supplied with water, which then flows out cleaned. More or fewer filter devices 1 can also be provided, and these can also be arranged square or rectangular when viewed from above. The filter devices 1 can, for example, each have two, in particular symmetrically arranged, inlets 4 and one outlet 6 each.

Such a filter device 1, or cleaning system 11, is, for example, stationary and can also function as a sewage treatment plant. However, it is preferably installed in a mobile manner, for example in a sailing ship; a trimaran would offer the process particular stability, and as it travels through the water, this water is absorbed, cleaned and released again. This means that algae blooms in seawater can be efficiently combated. Preferably, a significant portion of the energy required comes from a turbine drive, which is driven through the water by the ship's speed. After the flowing water passes the turbine and has given off part of its kinetic energy to it, the water is fed to the actual filter device 1 or the cleaning system 11. Likewise, a flowing or flowing body of water can be cleaned by such a filter device 1.

Reference symbol list

1

Filter device

2

Filter room

3

Housing

4

Intake

5

Filter membrane

6

Sequence

7

Fumigation facility

8th

Agitator

9

discharge device

10

foam

11

Cleaning system

S

Arrow

G

Arrow

D

Double arrow

L

Arrow

O

surface

Claims (6)

Filter device (1) for filtering algae, microorganisms and the like from water, comprising - an inlet (4), - a filter chamber (2), to which water can be fed via the inlet (4), - a filter membrane (5) for filtering out Algae, microorganisms and the like, - a drain (6) for the filtered water below the filter membrane (5), - a gassing device (7) for supplying a gas to the filter membrane (5), which is between the drain (6) and the filter membrane (5). is arranged, - an agitator (8) for mixing the water in the filter chamber (2) and - a discharge device (9) for discharging Foam (10) or impurities on the surface (O) of the water in the filter room (2). Filter device (1). Claim 1 , characterized in that a frother is assigned to the inlet (4). Filter device (1). Claim 1 or 2 , characterized in that the filter membrane (5) is made of ceramic. Filter device (1) according to one of the Claims 1 until 3 , characterized in that the filter chamber (2) is assigned baffles. Filter device (1) according to one of the Claims 1 until 4 , characterized in that the filter device (1) is designed such that cross-flow filtration takes place. Cleaning system (11) for filtering algae, microorganisms and the like from water, comprising several filter devices according to one of Claims 1 until 5 .

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