Experiences on greywater re-use for toilet flushing in a hotel (Mallorca Island, Spain) Original Research Article

An indoor greywater recycling system to flush the toilets in a hotel is described. The system is based on filtration, sedimentation and disinfection treatments using hypochlorite as the disinfecting agent. An average amount of water of 5.2 m3/d−1 was re-used, which represents 23% of the total water consumption of the hotel. A moderate hypochlorite dose (75 mg chlorine l−1) and a controlled residence time (<48 h) led to a residual chlorine concentration at cistern toilets higher than 1 mg l−1. Under such conditions, all samples were negative for total coliform bacteria. A maintenance program was proposed and an economics assessment was also reported. Customer acceptance was clearly satisfactory. This is the first paper reporting data on greywater reuse for toilet flushing in a hotel.