Tatiana Tkachenko 1 Ph.D., Associate Professor
1 Kyiv National University of Construction and Architecture, Povitroflotsky Avenue 31, Kyiv, 03037, Ukraine;
Received: 02/07/2019; Accepted: 03/30/2019; Available online: 04/29/2019.
*Corresponding author e-mail: firstname.lastname@example.org
Under a creative commons license.Volume 3, Issue 1, 2019, pages: 01-05.
Plagiarism was checked by iTenticate
Author Keywords: green roofs, rainwater drains, domestic needs, storage tank.
The article is devoted to the possibilities of purification of rainwater drains by using "green roofs" and their further using for domestic needs: watering the garden and the roof itself; toilets washing; laundry. To collect rainwater it is proposed to use the storage tank. The basis of the calculations are taken by the German method Wilo, adapted to the conditions of Ukraine. A significant contribution to this methodology is taking into account the uneven distribution and precipitation throughout the whole year and the lack of costs for watering the garden and roof in the winter period. Purified rainwater from "green roofs" can be assembled into tanks and used for technical needs. For collecting rain water from an intensive flat roof with an area of 200 m2 for the family of 4 people a tank of 5 m3 is required. In this case, the total needs for the house and watering the garden are 111 m3 / year, and daily needs - 0,341 m3 / day.
The advantage of "green roofs" in urbocenoses is not only in reducing the load on storm sewage and sewage filtration. Purified rainwater from "green roofs" can be assembled into tanks and used for technical needs (toilets washing, the using of washing machines, gardening etc.) [1,2]. Due to rising water tariffs, rainwater using is becoming more and more justifiable. The Germans consider that soon rainwater will be as commonplace as the separation of wastes, 60% of drinking water can be saved by using rainwater. These funds can be used for other purposes. But more important is the preservation of water, the most valuable resource. The environmental technologies of the German company Wilo  have the best reputation in the world for using of rainwater. This company has developed a handbook for using of rainwater. This manual provides examples of calculations of rainwater inflow, water demand determination, calculation of tank volume for rainwater storage and choice of water supply system. In addition, it is interesting and valuable to introduce a runoff coefficient (c) for different types of roofing surfaces, including for intensive and extensive green roofs. There is no such method in Ukrainian DBN В.2.6-14-97  and DBN В.2.6-220: 2017 . In areas where is a big part of the precipitation falls in the winter months, "green roofs" may not be as effective because there is less water retention in the winter. Consequently, efficiency increases in those regions where a significant amount of precipitation falls in the warm period. The technology of "green roofs" is used for quantitative and qualitative regulation of rainwater drains. Qualitative regulation of rain drains involves their filtration and reuse of wastewater, which saves valuable natural resources - water.
Thus, the important ecological and economic benefits of "green roofs" in modern urbocenosis are: reducing the amount of sewage due to evaporation and moisture absorption of plants; improvement of the quality of sewage due to natural filtration; reducing the load on storm sewage by reducing the rate of water flow. Purified rainwater from "green roofs" can be collected in tanks and used for technical needs. For collecting of rainwater from an intensive flat roof with an area of 200 m2 for a family of 4 people a tank of 5 m3 is required. In this case, the total needs for the house and irrigation of the garden are 111 m3 / year, and daily needs - 0,341 m3 / day.
 Cipolla S. S. Decentralized Water Management: Rainwater Harvesting, Greywater Reuse and Green Roofs within the GST4Water Project / S. S. Cipolla, M. Altobelli, M. Maglionico // Proceedings. – 2018. – № 2. – P. 673-680. – DOI:10.3390/proceedings2110673
 Using a Hydrological Model to Simulate the Performance and Estimate the Runoff Coefficient of Green Roofs in Semiarid Climates / J. Herrera, G. Flamant 2, J. Gironás, S. Vera, C. A. Bonilla, W. Bustamante, F. Suárez // Water. – 2018. – № 10(2), 198-214. – DOI:10.3390/w10020198.
Please cite as: T. Tkachenko “The reuse of rainwater drains by using «green roofs».” USEFUL online journal, vol. 3, no. 1, pp. 01–05, April 2019. DOI: https://doi.org/10.32557/useful-3-1-2019-0001