On Tuesday, October 11, the Green Walk - Green Talk, an excursion to a new residential building called Botanica K, which is developed by Skanska Reality, was organized in Prague - Jinonice. The buildings are designed in a low-energy standard and are the first residential buildings in the Czech Republic using grey water management, counting with the fact that purified water from washbasins, bathtubs and showers will be used for flushing. Among other things, a storage tank for rain water capture is placed near the house, which can be further used for watering the green vegetation around the house.
About a quarter of the consumption of drinking water is used for flushing toilets in every household. Only the inhabitants of Prague use about 33 000 m3 of quality drinking water for flushing daily. This amount is equivalent to the volume of approximately 9 swimming pools in Podolí. Due to Grey Water Management System, up to 25 % of drinking water is saved in Botanica K. At the full occupancy of the Botanica K apartments, the annual savings will exceed 3 500 m3, which corresponds to approximately 1 050 fire trucks.
The results of the research, which Skanska Reality had done before installing the system, were presented during the event. The survey of public opinion applied to the use of grey water in households, and showed that 91 % of respondents consider toilet flushing with grey water a good solution that should be used as much as possible. In addition, respondents would be willing to use grey water to:
- car wash (75%)
- watering flowers (59%)
- household cleaning (37%)
- showering (5%),
- filling up the aquariums (4%) or even drinking (1%).
As a motivation for the use of grey water, respondents mentioned the following:
- respect for nature (67 %)
- financial savings (65 %)
- future trend (36 %)
- more self-sufficient houses (34 %)
At the excursion, we looked at the completed K 3 & 4 building and the K 1 & 2 building which is under construction. The Botanica K1 & 2 building has already been awarded the "Interim Certificate for the International New Construction 2013 - Residential Scheme" as the first residential building in the Czech Republic, with 69,3 % score, just under the level of BREEAM Excellent, and targets the BREEAM Very Good also in the final certificate.
Ing. Kateřina Nováková, the chief of the construction, shared with us her subjective perception of building management according to the BREEAM rules. As pros and cons, she mentioned:
- Sorting of waste that helps more than expected and results in bigger cleanliness on the construction site.
- Covering the scaffolding with the nets which causes less dirt dropping out of the construction.
- No smoking, there is no need to solve a smelling stucco or cigarette stubs.
- Sometimes an unrealistic requirement for the level of cleaning at the workplace.
- A complicated providing of equipment with suction. However, alternative solutions for dust reduction can be found.
- Operating subcontractors and complaints of employees, for example on ban of listening to the radio.
We thank to participants and Skanska Reality and Skanska, a.s. for interesting information and the excursion of one completed and the other almost completed building.