Hoewel de rwzi’s Amsterdam-West en Horstermeer meer dan 99,8% van de microplastics verwijderen, blijft het absolute aantal dat in het milieu terechtkomt aanzienlijk. Tevens bleek dat één industriële textielwasserij verantwoordelijk is voor 13% van het totale aantal microplastics dat de rioolwaterzuivering binnenkomt.@en

Innovatieve ideeën over het gebruik van regenwater als bron voor huishoudwater of drinkwater lijken de laatste jaren als paddenstoelen uit de grond te schieten. Maar is het inderdaad een realistisch alternatief? En kunnen huishoudens hier zelf mee aan de slag of moet het toch centraal worden geregeld?@en

Often rainwater harvesting is considered as an important contribution to a more sustainable society. Rainwater is assumed to be clean water, requiring only limited treatment, and it is thought that there is sufficient rainwater available to provide people with drinking water. In order to check these assumptions, we carried out a desk study into the quality and quantity of rainwater. It was found that rainwater is cleaner than surface water, but still may contain contaminants. Especially the microbiological quality of rainwater is a point of concern, and therefore treatment, including disinfection, will be required. Furthermore, it was found that for densely populated areas, like a city district in Amsterdam, the quantity of rainwater that can be harvested from both built and paved surfaces equals only about half the amount that is required for the inhabitants. If rainwater is collected and treated at a neighborhood level, the costs are in the same order of magnitude as for centralized drinking water treatment. However, at the level of a single house costs are significantly higher. As rainwater requires less treatment than e.g. surface water, a small decrease in environmental impact may be realized. @en