9th WWW-YES, Belo Horizonte MG, Brazil, 26-30 October 2009 Rainwater harvesting: What are the Rainwater harvesting: What are the potential effects of roof maintenance on potential effects of roof maintenance on runoff quality? France as an example runoff quality? France as an example Antoine Van de Voorde LEESU (ex Cereve) Action financée par la région Ile-de-France
Plan Plan • Introduction • Methodology • Results / Discussion • Conclusion 2 WWW-YES, Rainwater harvesting, Van de Voorde
Introduction Introduction • Currently in France: ▫ Success of rainwater harvesting & re-use ▫ Governmental promotion harvesting & re-use (tax reduction) for soil cleaning, toilets,… • BUT… ▫ No reflexion about rainwater quality & risks associated � rainwater are « pure » ▫ Contaminations by trace metals (Robert-Sainte, 2009) & organic micro pollutants (Burkhardt et al ., 2007) 3 WWW-YES, Rainwater harvesting, Van de Voorde
Introduction (2) Introduction (2) • Practices are source of micro pollutants ▫ Cleaning the roof for embellishment ▫ Use of biocide • During rain possible leaching of these biocides � Necessary to evaluate level of contamination & risks of roof runoff re-use ! 4 WWW-YES, Rainwater harvesting, Van de Voorde
Methodology Methodology • Listing roof treatment products / Survey of professionals ▫ Determination of practices ▫ Knowledge of roof treatment undertaken • Compositions (SDS) ▫ Isolation of biocide molecule(s) & toxicity • Bibliography ▫ Types of contamination in countries where rainwater is drunk (developing countries, …) 5 WWW-YES, Rainwater harvesting, Van de Voorde
Results & Discussion: Listing / S urvey Results & Discussion: Listing / S urvey Number of Product type Utilisation products Primary • Fungicide is the most 3 Primary elimination of plants cleaning popular treatment Destruction of fungi and Fungicide 18 product incrusted lichens Increase of resistance to water Waterproofing 7 for porous material Embellishment / Paint 4 Waterproofing • Result confirmed by survey: 6 WWW-YES, Rainwater harvesting, Van de Voorde
Results & Discussion: Biocide used Results & Discussion: Biocide used R 1 Cl • Quaternary Ammonium Compounds - (QACs): + R 4 N R 2 • Toxicity: R 3 ▫ Highly toxic for aquatic environment (EC50 < 1 mg/L) H 3 C ▫ Irritant and allergen to skin contact, C n H 2n+1 + possible asthmatic reactions N CH 3 • For 100m² roof: 400g � 1000g of QACs � Risks exist for users and environment by mobilisation of QACs Alkylbenzyldimethylammonium (n° CAS : 8001-54-5) 7 WWW-YES, Rainwater harvesting, Van de Voorde
Results & Discussion: Drinking water Results & Discussion: Drinking water • Rainwater = Source of drinking water for countries without good or enough water ressources • Not a novel concept in Africa ▫ South Africa: Rainwater � major source of drinking water during rainy season ▫ Development in rural areas 8 WWW-YES, Rainwater harvesting, Van de Voorde
Results & Discussion: Drinking water (2) Results & Discussion: Drinking water (2) • For drinking water � Quality has to be good enough ! • Studies in New Zealand and India: ▫ Bacteriological factor limits the consumption of rainwater (for 30 to 90% of cases) ▫ Small proportion of chemical contamination but more difficult to eliminate � Risk by bacteriological & chemical pollution 9 WWW-YES, Rainwater harvesting, Van de Voorde
Conclusion Conclusion • Rainwater harvesting � contemporary issue • Contaminations exist for countries with good source of drinking water (a) and countries which need rainwater for drunk (b) • Sources of pollution different • Different approachs: ▫ (a): guide maintenance of roof and storage tank ▫ (b): increase knowledge of rainwater contamination & harvesting technics and guide population if possible health risks 10 WWW-YES, Rainwater harvesting, Van de Voorde
Thank you you for for your your attention attention Thank 11 WWW-YES, Rainwater harvesting, Van de Voorde
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