Safety guarantee technologies of water pressure and water quality: a case study in secondary water supply for high-rise buildings

With the rapid development of high-rise buildings in the past decades, the secondary water supply (SWS) has drawn great attention. In the traditional SWS of high-rise buildings, water pressure in the main pipeline is not enough to transmit water to high-rise rooftops, and thus water needs to be pumped to the rooftop water tank, then distributed to households with the help of gravity. Meanwhile, the water bio-indices assessment exceeds risk standards for the breeding of microorganisms and pathogens in rooftop water tanks. To avoid this phenomenon, the water pressure is boosted through an anti-negative pressure facility, and then water is distributed to households directly in the practical case of this work. Moreover, secondary disinfection, in which physical (ultraviolet) and chemical (sodium hypochlorite) disinfection techniques are combined, is implemented before the water enters occupants' homes. In this work, safety guarantee technologies of water pressure and water quality are successfully applied in a residential district of Suzhou, China. The results show that the qualified rate of water quality increases from 61% to 100%, and the water pressure fluctuates within 0.03 MPa.