Gray water
Gray water refers to faecal-free , low polluted waste water from baths, showers and washing machines, which by preparation of a secondary use as service or operating water can be used. Kitchen wastewater, on the other hand, is not included due to the higher pollution with fats and food waste. It is defined in the European standard 12056-1.
Gray water is usually cleaned in a purely mechanical-biological way, but bio-membrane filters are now also used. The clear water produced in this way is hygienically clean. It can be used for garden irrigation, house cleaning and toilet flushing ; Laundry can also be washed safely with it (if it is treated to the quality of bathing water, as is common in Europe). In a household with 4-5 people, the savings add up to approx. 90 m³ of water per year. In contrast to the weather-dependent rainwater harvesting, treated usable water is always available.
In the United States, attempts to reuse gray water have made garden irrigation more sustainable. In Japan and Europe, the main approach is to reuse gray water within the household as process water, in particular for flushing toilets. In Germany, institutions also rely on water recycling systems, such as the Hamburg Water Cycle .
processing
There are several possible ways to use household water twice. There is the possibility of having the corresponding systems built by specialized companies. Commercially available water recycling systems can also be purchased and installed by any plumber that are suitable for households. Corresponding systems simulate the process of wastewater treatment in a sewage treatment plant with sedimentation, aeration, anaerobic cleaning, and sludge separation. They are typically used where wastewater from several families, hotel rooms, etc. is brought together and treated together.
Another principle is based on an approach that is more intended for single-family houses, in which low-tech attempts are made to achieve maximum water savings with a minimum of storage volume, technology, acquisition and operating costs and a short downtime for the water to be treated. Rainwater (and only in the third instance: drinking water ) is used to buffer peak consumption . The typical per capita water consumption thus falls to values below 60 l / day.
According to a profitability analysis by the Wiesbaden University of Applied Sciences , gray water systems can already be operated economically in Central Europe with a connected number of users of around 150-200 people (e.g. in hotels). With high drinking and wastewater charges, rapid amortization is also otherwise likely. Due to the expected increase in the costs of water and wastewater, it is considered advisable to invest in a separate pipeline network for gray or possibly rainwater use when building a new building or renovating a residential building. In areas with greater water scarcity (e.g. southern Europe), greywater recycling almost always makes sense.
See also
literature
- Fachvereinigung Betriebs- und Regenwasser (Ed.): Water self-sufficient property . fbr series of publications vol. 15 (2011). ISBN 978-3-9811727-4-4 .
- Fachvereinigung Betriebs- und Regenwasser (Ed.): Greywater recycling - using water twice . fbr series of publications vol. 12 (2009). ISBN 978-3-9811727-1-3 .
- Fachvereinigung Betriebs- und Regenwasser (Ed.): Greywater recycling - planning principles and operating instructions . fbr information sheet H 201 (2005).
- Fachvereinigung Betriebs- und Regenwasser (Ed.): Industrial and rainwater utilization - inventory and vision for the future . fbr series of publications Vol. 10 (2005). ISBN 3-9804111-9-2 .
- Jörg Lange and Ralf Otterpohl : Wastewater. Handbook for sustainable water management . Donaueschingen - Pfohren , 2nd edition 2000, ISBN 3-9803502-1-5 .
- Jutta Kerpen, Dominik Zapf: Greywater recycling already economically profitable , Fach.Journal IHKS 2005/06: 88–92 ( download ).
- Klaus Werner König: Greywater use is ecologically necessary - economically sensible. iWater Wassertechnik, Troisdorf 2013, ISBN 978-3-00-039866-7 .
Web links
- Films on the topic of greywater use and Rainwater harvesting
- Project examples gray water utilization systems
- Entry into the problem of gray water use
- Function of a gray water system with mechanical-biological treatment
- DIY plant
- Function of a gray water system
- Gray water system based on a membrane bioreactor
- Films on the topic of decentralized water management
- The gray water blog on the Internet