Modeling water consumption and flow rates for flushing water systems in high-rise residential buildings in Hong Kong

The probable maximum flow rates and flushing water consumption of a residential development are two crucial design factors for flushing water plants and evaluation of the risk of overloading them. Flushing water demands are transient and influenced by occupant load variations, occupant usage patterns, installed appliances and system commissioning. This study proposes mathematical expressions to determine the water consumption and flow rates for flushing water systems of residential buildings in Hong Kong. The model parameters were identified from a recent survey on the water closet (WC) usage patterns of 14 high-rise residential buildings. The occupant load factor, diurnal variation of flushing, discharge and refilling durations and volume of the WC cistern recorded from 597 households were used to determine the uncertainties of consumption and flow rates, and hence the risk of overloading a plant. Predictions were made for two typical residential buildings in Hong Kong. Good agreement between the predicted and the measured flushing water consumption was found. This model would be useful in calculating the capacity of a flushing water plant and the associated risk of overloading it.

[1]  T Herrmann,et al.  Wastewater recycling concept for an urban multi-storey building. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[2]  John Swaffield,et al.  The engineered design of building drainage systems , 1992 .

[3]  J. A. Swaffield,et al.  Water, sanitary, and waste services for buildings , 1979 .

[4]  A. Fewkes,et al.  The recycling of domestic waste water. A study of the factors influencing the storage capacity and the simulation of the usage patterns , 1982 .

[5]  Eran Friedler,et al.  Characterising the quantity and quality of domestic wastewater inflows , 1995 .

[6]  C. L. Cheng,et al.  Evaluating water utilization in primary schools , 2004 .

[7]  Eran Friedler,et al.  Quantifying the inherent uncertainty in the quantity and quality of domestic wastewater , 1996 .

[8]  Eran Friedler,et al.  Domestic WC usage patterns , 1996 .

[9]  L. T. Wong.  Occupant Load Assessment for Old Residential High-Rise Buildings , 2003 .

[10]  V. Gardiner,et al.  Water Demand Forecasting , 1986 .

[11]  L. T. Wong,et al.  Determining the Domestic Drainage Loads for High-Rise Buildings , 2004 .

[12]  David Butler,et al.  The influence of dwelling occupancy and day of the week on domestic appliance wastewater discharges , 1993 .

[13]  L. T. Wong,et al.  Modelling the probable maximum demands of drainage systems for high-rise residential buildings in Hong Kong , 2004 .

[14]  L. T. Wong,et al.  Determination of domestic flushing water consumption in Hong Kong , 2005 .

[15]  M. J. Hall,et al.  Domestic per Capita Water Consumption in South West England , 1988 .

[16]  R. Birks,et al.  Using recycled water for non-potable, urban uses: a review with particular reference to toilet flushing , 2003 .