Method for operating a washing machine and washing machine

Method for operating a washing machine, wherein the washing machine has

• a drum for conducting a washing process therein,
• a sump located underneath the drum for collecting water exiting the drum, a water circulation including an extractible and/or removable drawer for introducing detergent or additives for the washing process,
• the water circulation being in fluid connection to detecting means for detecting microfibers or contamination in the water, and
• a circulation pump for circulating water in the circulation and pipes for connecting these components,
• wherein the method comprises the steps of:
• branching off an amount of water circulating in the circulation and transporting it to the detecting means for being analyzed,
• analyzing the water in the detecting means, and
• depending on the result of this analysis, activating a filtering process with filtering means for filtering out the microfibers from the water.