Main problem: In the modern world, we were able to solve many problems, but humanity continues to suffer from such tiny organisms as cyanobacteria. The main harm of these creatures is toxins they secrete in the course of their life. The products of their metabolism poison living organisms that live in water or use it for life. Also, in the process of active growth, cyanobacteria create a biofilm that inhibits the penetration of oxygen into water.

Inspiration: We were inspired by the concept of a science like bionics. Bionika is an applied science about the application of the principles of organization, properties, functions and structures of wildlife in technical devices and systems. Our filter simulates pores in the gills of a silver carp.

We team HydroModification , developed the idea of a filter for purifying water from cyanobacteria and the subsequent production of biofuels.

Main part: Cyanobacteria, or blue-green algae, are prokaryotes. Their average size is 0.5-100 microns. As a substrate, they use compounds of Nitrogen and Phosphorus (nitrates ad phosphates, which anre discharged into the river by production). Particularly actively they multiply with increasing temperature. The toxin content depends on the growth temperature. It was highest at 18 and 25 ° C, while at low (10 ° C) and high (30 ° C) temperatures, the toxin concentration decreased by 2–3 times (Sivonen and Jo/es, 1999).

In experiments with mice, cyanobacteria showed the highest toxicity at high and low pH values (Van der Westhurizen, Elloff, 1983). At high concentrations of phosphorus

in the environment, hepatotoxic strains produced 3-4 times more microcystins, but phosphorus did not have a similar effect on the synthesis of toxoid. In field research, a positive correlation was found between the microcystin-LR content in Microcystis aeruginosa cells and phosphorus concentration (Kotak et al., 1995).

In nature, a silver carp, or rather its gills, which have a special structure, is a natural filter for collecting cyanobacteria. The tissue retains large bacteria on itself, which served as the basis for our filter, due to its porosity. The filter is made of ABS plastic (acrylonitrile butadiene styrene). This material has many advantages:

- safety at standard temperatures;

- durability;

- neutrality towards living organisms;

- the possibility of recycling and reuse of material.

The filter can be divided into 3 parts:

- base;

- blades;

- collection tube.

The following are the parameters for a conditional model that has a base size -

21cm × 14cm × 0.5cm, blade size - 3cm × 14cm × 0.5cm and pipe diameter -2 cm, void diameter - 1.5 cm.

The base of the model consists of two plates placed relative to each other at an angle of 150 °, 5 mm thick, in which pores with a diameter of 0.0005 mm are located at a distance of 0.001 mm. It is precisely this size of the connector that enables us to retain medium-sized cells that are capable of producing offspring.

The blades also have pores, but they are located at a distance of 0.002 mm. It is done to ensure that water seeps through the pores of the base rather than the pores of the blade.

There is also a mesh in the pipe at the junction of all parts of the structure. The net at this location will allow bacteria to enter the pipe, which transports them to the bioreactor or collection container. Bacteria will stray into place with a net using water, which has a direction of its movement in different directions. The diameter of the opening in the grid is 0.12 mm.

The next part of the project is to obtain biofuels from blue-green algae. Biofuels - alternative energy derived from plant or animal raw materials, from the waste products of organisms or industrial waste. There are 4 generations of biofuels:

-generation biofuels are made from sugar, starch, vegetable oil and animal fat using traditional technologies;

-generation biofuel technologies are designed to extract useful raw materials from wood or fiber biomass containing useful sugars in cellulose and lignin;

-generation biofuels or algal fuels are made from algae;

-generation biofuels are made from cyanobacteria (blue-green algae).

Cyanobacteria belong to the last generation.

Cells during the destruction of the cell wall emit methane, which is an example of biofuel. It is the processes of death and destruction with gas synthesis that occur in the bioreactor. The design of the reactor is not complicated and has long been used in a variety of biotechnological industries. The main problem that we may encounter is the rate of membrane decomposition. This problem can be solved by adding an extract with a high concentration of cyanophages (cyanobacteria viruses) to the reactor, which contribute to the destruction of the cell wall.

When methane is oxidized, we get energy and safe concentrations of CO2 and H2O.

Resources user from NASA:

• https://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86449/balticbloom_oli_2015223_lrg.jpg
• https://earthobservatory.nasa.gov/images/86449/blooming-baltic-sea
• https://images.nasa.gov/details-GSFC_20171208_Archive_e001997
• https://images.nasa.gov/details-GSFC_20190621_Water_m13192_Quality
• https://images.nasa.gov/details-GSFC_20171208_Archive_e001502
• https://images.nasa.gov/details-GSFC_20171208_Archive_e001951
• https://images.nasa.gov/details-GSFC_20171208_Archive_e001812
• https://images.nasa.gov/details-185_GoodBadAlgae
• https://images.nasa.gov/details-GSFC_20171208_Archive_e000949Our filter is made of ABS - plastic, through the pores of which water passes, leaving bacteria on the cell structure. A stream of water, they are washed off into the tube.
• https://drive.google.com/drive/folders/1CfxEYGBm6tPRZ748-T35mVl4PQwpgkRR?usp=sharing