In 2018-2019 Esmil tube air diffusers were installed at the wastewater treatment plant in Chernihiv, Ukraine. The aeration system is a part of biological wastewater treatment facilities, and its task is to saturate the activated sludge and at the same time create a turbulent environment in the aeration tank. Esmil tube air diffusers are highly efficient and reliable, do not require maintenance and are resistant to mechanical damage. When operating in automated systems for controlling the oxygen concentration in the sludge mixture, Esmil aeration systems provide high speed of response to changes, which allows maintaining the optimal operating mode of the biological treatment equipment.
Since the beginning of March 2022, numerous airstrikes have been carried out in Chernihiv. Water pipes and repair equipment were destroyed, and water supply facilities were cut off from electricity. In the period from late February to mid-March, the power supply to the facilities of CE «Chernihivvodokanal» was unstable. Every day, Chernihivoblenergo specialists worked to restore power, but after intense bombing, the damage to the main substations and power grids became so severe that repair was impossible.
From mid-March to mid-April, water pumping stations, cold water booster pumping stations, sewage pumping stations and sewage treatment plants stopped due to a lack of power supply.
In the statement from the operating organization, Chernihiv WWTP describes in detail the operating experience of the aeration systems during the war and notes the following features:
“During 2018 in tank №3 and in 2019 in tanks №2 and №4 an aeration system at the municipal wastewater treatment facilities of “Czernihivvodokanal” has been replaced into tube air diffusers from the APKV-120 series with a total length of about 1700 m.
This allowed to reduce significantly electricity consumption, as the operation of one TV-300 blower fully satisfied the technological needs (previously there were two blowers). Total savings amounted to about one million UAH per year.
In addition, these diffusers worked very well during the period of active hostilities in our region, when electricity supplies were unstable.
In the period from March 15 to April 1, 2022, due to continuous shelling and significant damage to power facilities, the wastewater treatment plant of the city of Chernihiv was cut off from electricity. All the sludge and water mixture that was in the aeration tanks at the time of shutdown, sank to the bottom. Activated sludge in this form remained in tanks for two weeks.
After the electricity supply was resumed, the tanks were gradually put into operation (they were not emptied). After half an hour of work, the sludge and water mixture was mixed homogeneously, the air was supplied evenly, and the required intensity of aeration was restored in all corridors of the aeration tanks.
This proves that the dispersion layer of the diffusers was not clogged with organic matter and did not require additional rinsing and blowing in order to restore its properties.
The efficiency of the aeration system has not decreased.
During the period of operation, there were no failures in the operation of APKV series diffusers. Moreover, a fairly quick recovery period after operation in conditions of long-term power failure was noted.”