The subject of the invention includes a biological flow-through filter in the form of a stretched mesh on the surface of which there is development of immobilized biomass, intended for biological treatment of water or wastewater.

Wastewater is biologically treated first of all in systems with biomass in suspension state called activated sludge or attached to the carrying basis called a biofilm. It is also possible to treat wastewater in hybrid units forming the connection of a biofilm and activated sludge i.e. suspended biomass and fixed to carriers in one reactor in the form of a biological filter.

The advantage of the hybrid systems - combining features of an activated sludge and biofilm is the possibility of collection of much larger pollution loads in comparison with an analogous volume of a activated sludge reactor. Achievement of high concentration of biomass thanks to its retention on carriers increases stability of biological treatment of wastewater and elasticity in reference to changeable pollution loads flowing to the system. In addition, reactors with an activated sludge and biofilm show high tolerance of pH and temperature fluctuations as well as content of toxic substances. Application of additional biomass in the form of biofilm is of large significance in case of modernization of existing units, often hydraulically overloaded or with low effectiveness of biological treatment of wastewater. Improvement of efficiency of treatment concerns introduction of an appropriate basis into the tank of activated sludge for development of micro-organisms in the form of carriers for a biofilm.

The key factor for proper and stable development of micro-organisms of the biofilm is the basis which should ensure appropriate area of contact of microorganisms with substances removed from wastewater. Effectiveness of development of appropriate population of micro-organisms in the biofilm depends on the kind of carrier for immobilized biomass.

There are also known different types of systems combining the technology of activated sludge and biofilm. There are known different solutions concerning biological filters applied for biological treatment of wastewater or water.

The patent description No. PL 144779 shows an immersed biological filter built in the form of a rotating drum with filling.

The patent description No. PL 107006 shows the way of biological treatment and additional treatment of wastewater, watercourses, water conditioning with the use of pierced screens on which epiphyte organisms develop.

Description of the industrial model PL 17914 presents a flow-through filter in the form of a stylized cuboid with characteristic grating outline of frontal and side surfaces, including horizontally a number of parallel elements in the form of strips possessing on ends openings creating one or two or three or four or five or six or seven or eight or nine or ten layers whose longitudinal frontal edges possess symmetrically placed diagonal grooves which on opposite edges are shifted mutually by half of their length in which vertical elements are in parallel introduced in the form of strips forming one, two, three, four, five, six, seven, eight, nine, ten layers.

The aim of the invention is to create a flow-through filter with such 25 construction so that deposit will not be pasted, which makes it possible to avoid surge of biomass as well as excessive and uncontrolled overgrowth of carriers by a biofilm.

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh stretched on the frame. The mesh is made of a synthetic fibers rope of plastic, favorably of polypropylene, nylon or polyethylene with gauge from 5 to 50 mm. Applied mesh of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh may have the form of a twisted or braided rope with large contact surface area with wastewaters. Expanse between the ropes may create openings in the hexagonal form, openings in the shape of quadrangles, triangles or expanse in the form of a "cobweb".

The mesh' s frame is placed in guides resistant to corrosion caused by water or wastewater fixed inside the tank for treatment of water or wastewater. Favorably, the mesh's frame is placed in the tank of activated sludge. Placement of the mesh' s frame in guides makes it possible to evacuate the mesh filter onto the surface outside of the biological reactor. A catch may be fixed to the mesh's frame used for lifting it by means of a rope winch or crane fixed to the reactor's wall. The advantage of the solution is simple and light construction of the filter which makes it possible to evacuate outside of the reactor' s tank, existing shearing forces during flow of wastewater or water result in scouring away and tearing off of the excessively generated immobilized biomass in the form of the biofilm, which gives a result. Another advantage of the invention is simple and light construction of the filter which makes it possible to evacuate outside of the reactor' s. The existing shearing forces during flow of wastewater or water result in scouring away and tearing off of the excessively generated immobilized biomass in the form of the biofilm. This leads to more effective increase of biomass responsible for wastewater treatment.

Application of the mesh biological filter improves treatment of wastewater thanks to which a wastewater treatment plant will work in accordance with the water and legal permit.

The subject of the invention is presented in the following examples which do not limit this invention in any way, in the drawing on which fig. 1 shows the guide to the activated sludge reactor in which there is a frame with the mesh biological filter, fig. 2 presents the activated sludge reactor with suspended in it mesh biological filter with holes of the mesh in the shape of a "cobweb" in diagonal view from a side, and fig. 3 presents the cross-section of the activated sludge reactor, and fig. 4 presents the activated sludge reactor with suspended in it mesh biological filter with holes of the mesh in the shape of triangles in diagonal view from a side, and fig. 5 presents the activated sludge reactor with suspended in it mesh biological filter with holes of the mesh in the shape of quadrilaterals in diagonal view from a side, and fig. 6 presents the activated sludge reactor with suspended in it mesh biological filter with holes of the mesh in the hexagonal shape in diagonal view from a side.

Example I

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polypropylene fiber rope with gauge of 5 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh may have the form of a twisted rope with large contact surface area with wastewater. Expanse between the ropes is formed by triangular holes.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, may be fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor' s wall.

Example II

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a nylon fiber rope with gauge of 10 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a braided rope with large contact surface area with wastewaters. Expanse between the ropes is formed by hexagonal holes.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor.

Example III

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polyethylene fiber rope with gauge of 30 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a twisted rope with large contact surface area with wastewaters. Expanse between the ropes is formed by hexagonal holes.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewaters fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, is fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor's wall.

Example IV

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polypropylene fiber rope with gauge of 5 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh may have the form of a twisted rope with large contact surface area with wastewaters. Expanse between the ropes is formed by holes in the shape of quadrangles.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, may be fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor's wall.

Example V

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a nylon fiber rope with gauge of 10 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a braided rope with large contact surface area with wastewater. Expanse between the ropes is formed by holes in the shape of quadrangles.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor.

Example VI

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polyethylene fiber rope with gauge of 30 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a twisted rope with large contact surface area with wastewater. Expanse between the ropes is formed by holes in the shape of quadrangles.

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, is fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor's wall.

Example VII

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polypropylene fiber rope with gauge of 5 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh may have the form of a twisted rope with large contact surface area with wastewater. Expanse between the ropes is formed by expanse in the shape of a "cobweb".

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh biological filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, may be fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor' s wall.

Example VIII

The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a nylon fiber rope with gauge of 10 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a braided rope with large contact surface area with wastewater. Expanse between the ropes is formed by space in the shape of a "cobweb".

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh filter onto the surface outside of the biological reactor.

Example IX The mesh biological filter according to the invention includes immobilized biomass also called a biofilm creating a biological filter placed perpendicularly to the direction of flow of wastewater, developed on the vertical surface of a mesh 1 stretched on the frame 2. The mesh 1 is made of a polyethylene fiber rope with gauge of 30 mm. Applied mesh 1 of ropes is the carrier of bacteria and immobilized biomass. The rope used for making a mesh has the form of a twisted rope with large contact surface area with wastewater. Expanse between the ropes is formed by space in the expanse of a "cobweb".

The frame 2 of the mesh 1 is placed in guides 3 resistant to corrosion caused by water or wastewater fixed inside the tank 4 for treatment of water or wastewater. The frame 2 of the mesh 1 is placed in the tank 4 of activated sludge. Placement of the frame 2 of the mesh 1 in guides makes it possible to evacuate the mesh filter onto the surface outside of the biological reactor. A catch, not shown in the drawing, is fixed to the frame 2 of the mesh 1 used for lifting it by means of a rope winch or crane fixed to the reactor's wall.