LV15092B - Fish-rearing complex and method for regenerating water therein - Google Patents

Description

Description of the Invention

The invention relates to fish farming, in particular to closed water supply for fish and other aquatic organisms, and can be used for industrial fish farming.

Known state of the art

There are known closed water supply facilities used for fish farming in artificial pools. Various designs for such pools have been described in the literature (Thomas W Lawson, Fundamentals of Aquacultural Engineering, Springer US, 2011; Odd-Ivar Lekang, Aquacultural Engineering, John Wiley & Sons, 2013). Closed water fish farming facilities typically have a separate fish farming basin, mechanical and biological filter, anaerobic denitrifier and oxygenator, which are linked to each other by a pipeline and pump system. Such facilities are environmentally friendly, as they have virtually no wastewater, as well as biologically valuable waste from fish life processes is successfully recycled and used. However, the cost of fish farming for such facilities is very high due to the high energy intensity, the length of the pipes, the need for large building areas, the loss of energy and the complexity of temperature control.

Placing a fish tank and a water purification system in one basin significantly slows down and optimizes fish production. Such devices are gaining popularity. There are many technical solutions for optimizing such a placement.

The closest solution to the proposed invention is the patented fish farming equipment (patent LV13066). In this unit, the purification filter system is located in the same basin as the fish tank and is designed as a set of interconnected mechanical and biological purification sections. The first section is equipped with a mechanical purification filter, the other sections contain a biofilter with anaerobic and aerobic purification zones. Above one of the biofilter channel barrier thresholds, an ultraviolet lamp is used to disinfect the water. The purge filter sections are rectangular in shape with a zig-zag through-flow passage and a tapered funnel at the bottom of each section for settling and draining sludge. In the last section of the biofilter there is a pump which circulates water in the unit. The layout of all units is compact and takes up only the useful area without the need for a long pipeline. All structural elements are easy to assemble. The equipment provides the necessary degree of water purification and preparation, which allows the fish to be reared in densely spaced conditions, i.e. for industrial fish production. An attempt has been made to place the purification units compactly in this unit.

However, the sequence and arrangement of these devices have significant drawbacks. Placing the pump behind the biofilter requires high energy consumption to ensure the circulation of water and filler in the biofilter as well as further water circulation in the unit. An ultraviolet lamp placed above one of the biofilter barrier thresholds can disinfect only a small portion of the circulating flow, and the positioning of the lamp above the biofilter further reduces its disinfecting action due to the significantly lower efficiency of ultraviolet radiation in water with floating particles. The oxygenator, located above the fish breeding basin, enriches oxygen with only a small part of the water flow.

Purpose and substance of the invention

The object of the present invention is to improve the purification and oxygenation of water in a fish farming complex without making the process more expensive by placing all stages of water recovery in a certain order.

For this purpose, a water recovery unit is set up along the edge of the fish farming basin. Said unit comprises sequentially arranged individual sections connected by zigzag flow: denitrification settler; water lifting, aeration and circulation apparatus; biofilter section; degassing section; a disinfection section and an oxygen enrichment section.

A distinctive feature of the present invention is a water recovery unit having a defined sequence of sections and an improved function of individual elements of the recovery cycle. The water lifting, aeration and circulation unit is located between the denitrification settler section and the first biofilter section. The unit provides high volume lifting and circulation of liquid, thus fulfilling the function of both a water lifting device and an aerator. For this purpose, the body of the machine is formed by a lower part of a parallelepiped shape, above which is placed the upper part, the two opposite walls being parallel to each other but perpendicular to the base, and two other walls bent over the base of the rectangle. The following biofilter sections with a bottom tapered bottom are divided by two partitions. Inside the compartment, vertical downward walls separate the downstream stream of purification water and the upstream stream of water and filler through the aerator air. The tops of the bulkheads are below the water level of the biofilter and form water barrier thresholds, facilitating its circulation in the biofilter. The bottom edges of the bulkheads do not reach the bottom slopes of the biofilter, providing flow for downstream streams for aerobic treatment. Behind the biofilter sections is a degassing section, further down the disinfection section. In the disinfection section above the wall (above the thinnest layer of water), which separates the amount of contaminated water from the treated water reservoir and forms a water barrier threshold, an ultraviolet emitter is enclosed with a shroud that limits the radiation exposure area and directs the radiation to the flow of water over the barrier threshold.

In the oxygen enrichment section, a chamber for oxygen enrichment is provided with an airtight housing fitted with an oxygen conduit. The airtight shell covers the flow of water that moves from the biofilter section across the partition wall and is enclosed by a tray from below. The tray directs the flow of water to a mesh basket containing a plastic filler. The basket is attached to a tray and placed above the fish basin such that a space is created between the airtight shell, the basket walls and the water surface of the fish farming basin to mix oxygen with water droplets. The stream of water is first exposed to the stream of oxygen from the oxygen duct. Oxygen interacts with the supernatant of water and is dispersed in the space below the airtight shell. The water flow is then passed through a basket of plastic filler installed above the fish farming basin. Flowing through the basket with plastic filler, the water is sprayed in the form of droplets, which when mixed are mixed and oxygenated. Oxygenated water flows into the fish farming basin.

The attached drawings show:

Fig. 1 - fish farming complex where the water recovery unit is located between two fish basins (top view);

Fig. 2 - fish farming complex with water recovery unit;

Fig. 3 - Side view of a fish farming complex.

DETAILED DESCRIPTION OF THE INVENTION

The fish farming complex operates as follows: contaminated water from the fish breeding basin (1) or basins (1,2) flows in a by-pass to the denitrification settler (3) and flows into the next section where the water aeration, circulation and lifting equipment is located. (4), further as shown in Fig. 2, water flows through the biofilter (5) section, the degassing section (6), through the lower inlet to the disinfection section (7), where disinfection is performed above the barrier threshold in the thinnest water layer by means of ultraviolet radiation, the water then enters the oxygen enrichment section of the water, which consists of a chamber enclosed at the top with an airtight housing fitted with an oxygen tube. First, the stream of water is affected by a stream of oxygen from the oxygen duct. Oxygen interacts with the supernatant of water and is dispersed in the space below the airtight shell. The flow of water is then directed through a 5 plastic basket filled over the fish farming basin. Crossing the basket with a plastic filler, the water flow is sprayed in the form of droplets, which are mixed with oxygen when they fall. Purified and oxygenated, the water returns to the fish farming basin.

The advantage of the proposed fish farming complex over the already known plant solutions is the optimization of the water recovery process with a minimum of 10 energy consumption due to the complex use of a water lifting, circulation and aeration unit located before the biofilter sections. The proposed biofilter sectional design improves biological water purification without additional costs. Placing the disinfection section after the degassing section and creating an adjustable barrier threshold for obtaining a thin layer of water allows for a significant increase in disinfection efficiency in the fish farming complex. The oxygen enrichment method and plant are not only effective but also simple in performance. The proposed fish farming complex and water recovery method in it allows to improve biological purification, disinfection and oxygen enrichment in industrial low energy fish farming.

Claims (12)

1. A fish farming complex with a closed water supply system comprising a basin for fish, a biofilter, an aerator, an ultraviolet lamp, an oxygen enrichment plant, characterized in that a water recovery unit is arranged along the entire length of the fish tank and the water flows through it sequentially. arranged in separate sections: denitrification settler (3), water lifting and circulation unit (4), biofilter (5), degassing section (6), disinfection section (7) and oxygen enrichment section (8). Fish farming complex according to claim 1, characterized in that the water recovery unit can be located between two fish basins (1, 2). Fish farming complex according to claims 1 and 2, characterized in that the water lifting and circulation device (4) comprising a vertical hollow body with an aerator located in its lower part, is formed from the lower part of the parallelepiped shape, above which are the upper part, the two opposite walls of which are parallel to each other but perpendicular to the base, and the other two walls are inclined over the base of the rectangle. Fish farming complex according to claims 1 and 2, characterized in that one or more biofilter sections (5) are arranged in the water recovery unit. Fish farming complex according to claims 1 and 2, characterized in that each section (5) of the biofilter is divided by two vertical partitions formed in such a way that the tops of the partitions are below the water level of the biofilter and form a barrier. thresholds for circulating water and biofilter plastic filler streams, but the bottom edges of the bulkheads do not reach the bottom of the biofilter bottom, providing flow for downstream streams for aerobic treatment. Fish farming complex according to claim 1, characterized in that the disinfection section (7) is provided with an ultraviolet emitter located above the barrier threshold along its entire length, with the thinnest layer of water shielded by a sheath that delimits the area of exposure to ultraviolet radiation and directs ultraviolet radiation to a stream of water flowing over the barrier threshold. Fish farming complex according to claim 1, characterized in that the oxygen enrichment section (8) comprises a chamber formed by an airtight housing in which an oxygen conduit is mounted, the airtight housing covering a flow of water moves from the biofilter section across the separating wall and is enclosed at the bottom by a tray that directs water flow to a mesh basket containing a plastic filler, the basket being attached to the tray and positioned above the fish basin such that between the airtight shell, basket walls and a space for mixing oxygen with water droplets is formed on the surface of the fish breeding basin. A process for recovering water from a closed fish-feed plant according to claims 1 to 7, characterized in that the contaminated water from the fish-breeding basin is directed to a regeneration unit and is sequentially passed through all sections - denitrified in the settling vessel (3). ; aerated and lifted with the effect of a lift; subjected to biological treatment by passage through biofilter sections (5), degassed, ultraviolet disinfected and oxygen enriched. A method according to claim 8, characterized in that the device (7) employs an elevator effect to raise and circulate water and the aerator is positioned at the base of the housing to improve the circulation of water and plastic filler. A method according to claim 8, characterized in that the biofilter (5) separates downstream purification water flow and aerator air upward water and filler flow in the biofilter (5), while at the top forming barrier thresholds which promotes additional circulation of water and biofilter filler. A method according to claim 8, characterized in that the disinfection is carried out above the barrier, in the thinnest layer of water, by means of an ultraviolet emitter located over the barrier threshold along its entire length. A method according to claim 8, characterized in that in the oxygen enrichment section of the section (8), the stream of water is first exposed to a stream of oxygen from the oxygen duct, the oxygen interacting with the supernatant of the water and dispersing in the space below the airtight housing; the water flow is then passed through a basket of plastic filler mounted above the fish farming basin; flowing through the basket, the water is sprayed in the form of droplets, which are mixed with oxygen when it falls, and the oxygen-enriched water enters the fish farming basin.