Grey water system in residential project

Project

267892

Status

Submitted

Award category

You want to submit

NEW EUROPEAN BAUHAUS AWARDS : existing completed examples

Project title

Grey water system in residential project

Full project title

Description

A residential project Botanica K has been the first residential project in Czech Republic to start using the grey water system. The water flowing down the drains of showers, bathtubs and bathroom sinks – water only slightly dirty – could receive basic water treatments, such as filtration and disinfection. Then this treated "grey water" could be piped back into bathrooms to use to flush toilets, rather than drinking water.

Where was your project implemented in the EU?

When was your project implemented?

Has your project benefited from EU programmes or funds?

Which programme(s) or fund(s)? Provide the name of the programme(s)/fund(s), the strand/action line as relevant and the year.

Please provide a summary of your project

Botanica K was the first in the Czech Republic to be certified BREEAM Excellent (an international environmental certification) as well as the first to introduce its residents to a greywater management system. The system takes used water from sinks, baths and showers and reuses it especially for toilet flushing. This lets households lower drinking water consumption by up to 26%. Skanska plans to put its experience to work on its next residential project, Čertův vršek, and is prepared to share this experience with the professional public so that legal standards and hygiene and construction regulations can be updated to reflect this new technology.  

Please give information about the key objectives of your project in terms of sustainability and how these have been met

In 2018, the Botanica K project reused 26% of its overall drinking water consumption. In absolute numbers, the total amount of drinking water used in the building was 4 834 m3 and of that amount, 1,241 m3 (1,241,000 liters) of greywater was used for flushing toilets. That’s the amount of water it would take to fill a standard-size tub of 150 liters every day for 22.5 years. The drinking water saved would fill 75 tanks of 16 m3 each.

Please give information about the key objectives of your project in terms of aesthetics and quality of experience beyond functionality and how these have been met

As part of this assessment we surveyed residents. Eighty-six percent of respondents say their experiences with the toilet flushing system are satisfactory to very positive. Ninety-six percent perceive the use of grey water in their home as a positive. "From a user perspective, we don't actually observe anything in our daily life, meaning that it does not limit us in any way," says one resident. "We are happy that the water is not colored. We also like the savings and the partial independence of the building."

Please give information about the key objectives of your project in terms of inclusion and how these have been met

Surely, there must be a more responsible way of flushing toilets, especially as water is increasingly scarce in the Czech Republic and other lands. By 2025, half of the world’s population will live in "water stressed" areas, according to the World Health Organization. And with more and more urbanization, adapting buildings to use water in smarter ways is a big opportunity to be ready for a future in which fresh water is likely both less consistently available and more expensive.

Please give information on the results/impacts achieved by your project in relation to the category you apply for

Over the system's first six months, about 550 cubic meters of drinking water was conserved, producing a savings of CZK 50,000 (about SEK 20,100) on residents' water bills. Now later in the year, even more drinking water is being reused, about 25 percent on an average daily basis. We expect the system will pay for itself in 15 years, considering current energy and water costs.

Please explain the way citizens benefiting from or affected by the project and civil society have been involved in the project and what has been the impact of this involvement on the project

As part of this assessment we surveyed residents. Eighty-six percent of respondents say their experiences with the toilet flushing system are satisfactory to very positive. Ninety-six percent perceive the use of grey water in their home as a positive. "From a user perspective, we don't actually observe anything in our daily life, meaning that it does not limit us in any way," says one resident. "We are happy that the water is not colored. We also like the savings and the partial independence of the building." Together with other water saving features – namely water sipping faucets and showerheads, as well as collecting and reusing rainwater for irrigation – about 40 percent of the drinking water consumed daily in households is being conserved.

Please highlight the innovative character of the project

Skanska plans to incorporate grey water recycling in other residential buildings that we develop in the Czech Republic, and we are increasingly using grey water and rain water to flush toilets in commercial office buildings in Central Europe and the US. We’ve even created one US building that transforms rain water into drinking water, and that features composting toilets that use no water at all.

Please explain how the project led to results or learnings which could be transferred to other interested parties

Together with other water saving features – namely water sipping faucets and showerheads, as well as collecting and reusing rainwater for irrigation – about 40 percent of the drinking water consumed daily in households is being conserved. This savings is important to Botanica K's targeted achievement of the second-highest level in the international BREEAM green building certification. It would be the first residential building in the Czech Republic to carry the BREEAM label.

Is an evaluation report or any relevant independent evaluation source available?

By ticking this box, you declare that all the information provided in this form is factually correct, that the proposed project has not been proposed for the Awards more than once under the same category and that it has not been subject to any type of investigation, which could lead to a financial correction because of irregularities or fraud.