English
Български 
- Thursday, 27 January 2022
A forest plant carpet will show whether it could help ease the sewer system during rain
The end of 2020 actually turned out to be the bold beginning of a new innovative collaboration between “Sofiyska Voda” JSC and the Center of Competence “CLEAN and CIRCLE.” Our company supported the research team of “CLEAN and CIRCLE,” which includes experts from UACEG and Sofia University “St. Kliment Ohridski,” in a project to study the dynamic relationship between rainfall and runoff in the sewer system. For this purpose, we found the most suitable of our buildings with a flat roof that drains rainwater separately from domestic wastewater. The building of the recirculating sludge pumping station on the territory of the Kubratovo WWTP turned out to be ideal. The project first included preparation of the building itself, installation of measuring devices and a rain gauge station. Meanwhile, a UACEG team won a project under the CENTER FOR SCIENTIFIC RESEARCH AND DESIGN at UACEG, aimed at greening part of the roof and monitoring the effect of the greenery and the quality of the rainwater.
It was only in the fall of 2021 that the “green” roof was completed, and the observation and analysis phase began.
What is the idea?
To analyze to what extent greening a roof with specially selected mountain moisture-loving vegetation can reduce the amount and speed of runoff during rainfall and thus ease the load on the sewer system.
What are we doing?
During preparation, the roof was divided into two halves: one remained with standard bitumen covering, while the other was prepared for greening. A separation was made between the two halves so that rainwater falling on one side would not overflow into the other. Under both rain gutters of the building, a UACEG team installed flow meters, which have already started measuring water runoff from the roof. At the same time, our team installed one of our rain gauge stations on the roof to measure rainfall amounts. This way, we aim for maximum accuracy when comparing rainfall measurements above with water runoff through the gutter below.
The green moment
The installation of the “Green Roof” was carried out in the fall of 2021, to coincide with the rainy season and allow the vegetation to take root. Already at the first visit of the UACEG colleagues, on a damp and foggy day, the specialists noticed that the gutter from the “bare” roof had started dripping, while the one from the greened section remained dry.
What’s next?
We are looking forward to spring and the new active rainy period this year. The project continues with analysis of the collected data, measurement of the qualitative parameters of the rainwater, and all of us are also waiting for the mosses to turn green.
*The work is carried out jointly with UACEG through the project BG05M2OP001-1.002-0019: “Clean technologies for sustainable environment – water, waste, energy for circular economy,” funded by the Operational Program “Science and Education for Smart Growth,” co-financed by the European Union through the European Structural and Investment Funds, as well as through the CENTER FOR SCIENTIFIC RESEARCH AND DESIGN at UACEG.
