• This is how the South-West treatment facilities settling ponds look from height

  • In aerotanks air is injected so that the active silt microorganisms can breathe and purify water

  • Svetlana Sladkova, Researcher, RAS Research Center for Environmental Safety, and Australian crayfish

  • «If the crayfish health is good, in the cold season they will return here», says Svetlana Sladkova

  • To change the animals, experts remove the sensor from crayfishes and attach it to a mount on the armor of others

  • Have a good shift, colleague!

  • If all six crayfishes heart rate increases, the red signal of the traffic light system in the control room will light up

  • On the occasion of the crayfish replacement a press tour took place: journalists were able to learn all about biomonitoring

Special Report: How Crayfishes Work at Wastewater Treatment Plants

Nevsky Crayfish is not only our main character and representative in social networks. He is also a well-deserved worker - along with other crayfishes he controls the quality of water treatment in the South-West treatment facilities of St. Petersburg Vodokanal. When does Nevsky Crayfish go on vacation? Why do we need to change our crayfish on the outlandish ones, and how is the biomonitoring system arranged? Nevsky Crayfish will tell and show you right now.

How is water purified? So, we are on the South-West treatment facilities. Here, the city runoff turns into clean, environmentally safe water that can be safely returned to the Gulf of Finland. This magic occurs in several stages. First one is mechanical cleaning: removal of large and small debris, sand and various impurities. Then goes the biological one: water enters aerotanks, where microorganisms (activated silt) destroy various organic compounds. And then comes the time of chemical cleaning, and an effective super-reagent - aluminum sulphate is taken for work. It releases water from phosphorus, a dangerous enemy of all water bodies (it is phosphorus that leads to the spread of blue-green algae). As a result, the quality of wastewater treatment meets HELCOM's stringent recommendations (the Helsinki Convention for the Protection of the Baltic Sea against pollution). Since 2008, the level of phosphorus in the wastewater treated with sewage has been below 0.5 mg / l, and nitrogen - 8 mg / l. But that's not all! Purified water is also UV disinfected. And only after this we, the crayfishes, proceed to our duties.

And what do crayfish do here? The biomonitoring system, in which I work, has appeared on the treatment facilities in 2011. In total, we are six - experts have established that it is just so many crayfishes that are needed to obtain objective data. Our team is purely masculine - and there is no discrimination, males of arthropods are more restrained and resistant to stress. Why is it so important? Because the quality of water is assessed by our behavior and changes in the heart rate. And anxiety over trifles can spoil everything.

We sit in aquariums, through which purified water flows, and special sensors, fixed on shells, transfer data to the computer. And if something is really wrong with the water, our hearts will start beating more often, the dispatcher will receive an alarm signal, and the necessary measures will be taken.

Why do I have crayfish holidays? I go on vacation every year, as many of you do - in the summer. This is not accidental: in the warm season, the temperature of the sewage water rises. And we, river crayfishes, you know, use to live at 22-23 ° C. All that is above this for us is discomfort and stress, and therefore, when overheated, we can make a false alarm. That's why there is a change: during the summer season, Australian red-cheeked crabs are working, and we are resting. They are accustomed to heat, for them water up to 31 ° C is the norm. However, this year I had to work overtime due to the fact that the summer in St. Petersburg was not in a hurry. Sewage was heated only by 10 July, and usually I already have a rest in the laboratory from May to early June. After the holiday, when the cold comes, the Nevsky crayfish will start working again. The main thing is to pass the examination and confirm that you are fit.

I am very proud to receive such an important job, but, of course, not only crayfishes on the South-West treatment facilities are monitoring the cleaning of drains. We, animal-bioindicators, supplement the work of online control devices and laboratories. However, only crayfishes are able to simultaneously evaluate the totality of all the water characteristics in which they are located. And not just the amount of phosphates or nitrates, for example. It is a fact.

Стать другом Невского рака может каждый!

Силами Disqus