When the wind blows from Bortnychy aeration station, residents of Krarkivski area close windows and try not to go outside. No surprise, as the sewage water from every apartment, every enterprise and institution of Kyiv flow in sewage treatment works of Bortnychy. To learn how sewage water gets cleaned, ForUm went to the Bortnychy aeration station (BAS).

At the main entrance it is clean and bad smell is hardly perceptible.

The leading engineer of BAS Ihor Berezan, who knows the station inside out, was meeting us at the entrance to make a tour.

The first unit of the station was built in 1965, the second - in mid-1970ies and the third, the newest one - in 1986. "When the first waste treatment facilities were built, the surrounding territory was woods and swamps. Thus, residents' complains about bad smell should be readdressed to city planners. It was them, who built Kharkivski residential area near the station," he underlined that BAS is the only works of the city, and all sewage pipes come here. "There are talks that the city needs a new aeration station, but if they built new one they would also have to rearrange sewage pipes under a half of the city. Such works cost huge money, thus it would be more properly to reconstruct the operating one," Berezan noted.

With this model he explained us how the city authorities planned to get rid of bad smell. According to the pilot project, every cleansing reservoir was supposed to be covered with protective domes.

"I want you to understand that all facilities on the station are property of the Kyiv city, and two communal departments of the city administration are responsible for development and application of new technologies. Thus, if what to know what happened with the project, you should the city authorities," the engineer underscored.

These are the gates to the cleansing structures. Several collectors send sewage water to the receiving tank of the pumping station. The air stinks...

These huge pumps send sewage water for cleansing.

At the first stage, the water gets cleaned from coarse litter - cloth, plastic bags and dishes. This is the task of the rake device. Water passes through the bar screen, leaving coarse litter behind.

Workers of the stations take out up to 9 tons of waste daily and bring it to the  waste incineration plant "Energy".

Water, cleaned from coarse litter, goes to the grit-removal plant, which removes mineral particles. Particles gravitate under the action of gravity, while water moves on.

This one is the primary radial-flow settling tank. Water arrives in the center of the device and moves to the borders for couple of hours. This time is enough to separate water from heavy particles, missed by the grit-removal plant.

Water at the exit contains only dissolved matters.

Though there is no fish, for gulls all is fish that comes to their net.

Following the course of cleansing, water goes to aerotanks for biological treatment with the help of microorganisms.

"The aerotanks contain activated sludge to clean the water. The natural process takes about a month, but we do not have all this time, thus we add oxygen to speed up the process. At the bottom of the tanks there are pipes, which oxygenate the water, creating boiling mixture. Reproduction of microorganisms speeds up and the cleansing process takes about four hours," Berezan explained.

After this water goes to the secondary radial-flow settling tank, where it gets cleaned from activated sludge.

Here is the reservoir without water. Metal scrapers collect the gravitated activated sludge. Part of the 'yield' is used repeatedly, and another part is brought out to sludge fields.

But before bringing the waste out, it must be aseptisized. Waste is put in the sludge digester, and under 70 degrees it disintegrates and gets aseptisized, producing methane in result. "There are talks on implementation of alternative fuel - biogas. But sludge digesters do not produce sufficient amount of gas even to heat one digester," the engineer told.

Here is the cemetery of BAS waste. It is a reserve field for disposal of activated sludge. It looks like a wild abandoned field, but be aware that under the upper crust there is half a meter deep swamp.

Main sludge fields are located in Boryspil district and measure 272 hectares. The fields were designed to contain 3.5 million cu m of sludge maximum, but now there are all 10 million cu m of waste. The matter is that before 1985 the removed activated sludge was used as a fertilizer for industrial crops. But after Boryspil sanitary service had examined the waste for heavy metals, the sludge was banned from serving as a fertilizer. 

"Almost all countries in the world renounced the waste accumulation practice, as it requires huge territories. Our sludge fields are overloaded, and if the issue is not solved in the nearest future, the field's dams either will collapse and let out all the waster or our stations will no longer be able to bring out the sludge and will have to discharge not fully cleaned water into Dnipro," Berezan said.

According to him, the best method to dispose waste is mechanical drying on the principle of washing machine. "Waste sludge goes in a fast rolling cylinder. As a result, the volume of waste reduces by ten times. "And if we burn it afterwards, the volume reduces by another ten times. The ash can be used for roadwork or construction. Now we have only dead-weight and overloaded fields," the engineer complained.

But let's go back to the water. After the secondary tank the water goes to these cascades.

These are brush mixing basins, which oxygenate the water. "The station does clean the water totally. And to make it clean itself after we oxygenate it," Berezan explained.

Finally the freedom...

Cleaned water goes to the main watercourse, nine and a half kilometers long, and then falls in Dnipro through dispersive drainage system. The ratio of the stream and cleaned sewage water is one-to-forty," the engineer assured.

The cleansing mechanisms have not been replaced since 1960ies, and the quality of sewage water has worsened, Ihor Berezan complains. The water is now contaminated with combinations of nitrogen and phosphorus, as the result of usage of modern detergents, which contain phosphates.
The three units of the station are pretty worn-out and can barely manage to clean the water. "A part of the first unit is almost out of order, and some cleansing structures of the third unit are closed for repair. The station is losing its capacity. In 1960ies the station was designed to process a million and a half cu m of water per day. But for half a century the cleansing structures have seen hard wear, and now the station can manage one million maximum.

In response to ForUm's question whether BAS workers try to draw the attention of state officials to the problem Berezan laughed. "We do it continuously. There were cases that after passing all the offices of the Kyiv state administration our requests came back to us."
With every passing year the capital grows. Multi-storeyed buildings, trade centers, enterprises - they all increase stress on the one and only aeration station. If it stops working, the life in Kyiv and suburbs will become impossible due to ecological disaster in Dnipro. We hope state officials realize the level of risks and will finally direct their eyes to the Bortnychy aeration station.

Alina Yeremeyeva, photos by Maxim Trebukhov


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