Applications

Applications


Fighting eutrophication

Eutrophication is a natural mechanism of nutritive substances (phosphor and nitrogen) proliferation in water, which combined to a temperature increase and a high luminosity, generates an accelerated development of algae, microorganisms and invasive plants in a basin. This phenomenon is facilitated by water stagnation. These nutrients usually come from fish waste by-products, dead leaves decomposition, fish food, rotting aquatic plants or chemical products and fertilizers that have infiltrated the pound. The decomposition of these algae provokes a high concentration of organic matters that accelerates siltation and causes an excessive consumption of oxygen, asphyxiating the aquatic environment, degrading the ecologic condition of water (odour, colour, taste, toxicity…) and heavily reducing the number of surrounding species.

THE SLQI SOLUTION

The micro bubbles generator is a solution adapted to fight against basin eutrophication, acting during two steps of the process:
- Firstly, the generator enables a water brewing operation that is going to limit and considerably reduce the presence of the nutrients necessary to the algae proliferation.
- Secondly, the oxygen dissolved in water throught the micro bubbles process will re-establish and maintain the treatment process in the aerobic mode. The number of aerobic bacteria that feed themselves on nutrients is going to increase, which will lead to a strong diminution of the number of the nutritive substances. The progression of algae and invassive plants will be then strongly limited.



Microbubbles generator effects:
- Algae decrease
- Invasive plants reduction
- Bad smelles eradication
- Water quality reestablishment


Industrial sewage treatment

Used water has to be treated before being reintroduced into other water sources so it does not pollute them. Industrial waste waters (agro-alimentary, paper makers, micro-electronics...) are the most difficult to handle. their increased charge in COD (chemical oxygen demand) and in BOD (biological oxygen demand) needs an intense treatment before the water is evacuated in the environment.

THE SLQI SOLUTION

The generator's micro bubbles are negatively charged. This feature enables them to bring along all the matters in suspension during the ascension. Contrary to normal-sized bubbles, micro bubbles penetrate the notches of the microorganisms and completely encircle them to bring them to the surface. The utilization of a micro bubbles generator enables wastewater treatment throught the phase separation phenomenon.
Besides, the air supply through the dissemination of micro bubbles will allow a sufficient concentration of dissolved oxygen for biological activity in order to allow the degradation of organic matter in the case of treatment with activated sludge.


Aquaculture

In aquaculture and fish farming, an excellent maintenance of water quality (in matter of bio-mass and oxygen) is essencial. When a low water flow is combined to a high temperature, the amount in oxygen of the medium tends to not be optimal. The oxygen consumption being higher during food intake and digestion, an insufficient oxygen rate provokes a disminution of the food consumption expressed by a loss of growth among the fish and the augmentation of their organic waste. Moreover, some bacteria or viruses that are harmful to the environment since they may cause deadly infectious diseases.

THE SLQI SOLUTION

- Thanks to the air contained by the micro bubbles that spread through the basins, the oxygen rate is saturate and allows the optimal growth of all the farming fish.
- Using the nozzle directly with oxygen, the micro bubbles have a bactericidal action that reduces to zero the number of harmful bacteria in the environment without generating by-products such as chlorine (chloramines) and bromine (bromamines).

Effect on Vibrio bacteria:
The searching of vibrio bacteria was performed according to the standard NF ISO 8914 (May 1991):
Use of the selective culture medium TCBS for vibrio bacteria.


 Milieu TCBS avant inoculationDéveloppement de colonies de vibrions sur milieu TCBS

Picture 1 :TCBS medium before inoculation | Picture 2 : Development of vibrio colonies on TCBS medium 

To measure this bactericidal effect, we measure the number of CFU / ml (colony forming units).

7 m3 basin - seawater : **

Bactericidal activity diffusing a mixture of air + O2 with the UμBF-21 nozzle. There is a progressive decrease in the number of vibrio in function of the time of treatment.
In one hour, 58% of vibrio were removed at a flow rate of air enriched with 3 L O2/ min.

Effects on Escherichia coli:
The searching of these faecal bacteria was performed according to the standard NF EN ISO 9308-3 using micro plates MUG / EC that allow the enumeration of Escherichia coli in water.


The use of micro plate with wells that contain a specific suitable medium was developed for use in the analysis of several types of water, including bath areas in the sea and in fresh water, and surface water or wastewater. The method is applicable to all waters, including those that are rich in suspended solids.
For the enumeration of Escherichia coli, the technique using microplates with MUG has been recognized as being more specific, more precise, more accurate and faster than previous methods and is achieved by detecting the activity of the β-glucuronidase enzyme.

Test performed in two distint basins (pool-type) from 60m3 filled with filtered seawater, no animals: **

The addition of faeces and the system shutdown produces a significant increase in the number of these bacteria. The startup of the nozzle causes a rapid decrease of these bio-indicators, reaching even a complete eradication.
At a further addition of faeces and a new shutdown of the nozzle, the bacteria grow again but much slower thanks to the still present O2 in the water and these bacteria are rapidly removed again.