Open AccessModeling Graywater in Residences: Using Shower Effluent in the Toilet Reservoir
Author(s) -
Xing Wu,
Burcu Akinci,
Cliff I. Davidson
Publication year - 2007
Publication title -
journal of green building
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.248
H-Index - 21
eISSN - 1943-4618
pISSN - 1552-6100
DOI - 10.3992/jgb.2.2.109
Subject(s) - shower , greywater , toilet , flushing , environmental science , effluent , environmental engineering , waste management , wastewater , hydrology (agriculture) , engineering , medicine , geotechnical engineering , mechanical engineering , endocrinology , nozzle
Use of municipal water in residences can be decreased substantially by allowing “graywater” effluent from showering and other activities to fill the toilet reservoir. This paper considers a system developed in Germany for treatment and storage of shower wastewater for use in flushing the toilet. Based on literature data for distributions of shower duration and water flow rate, the volume of municipal water saved using the German system has been estimated for several usage scenarios. Results show significant savings of water that depend on the size of the treatment and storage tanks used in the graywater system as well as the number of toilet flushes per day. For example, a scenario with four residents each flushing nine times per day with 80 liter treatment and storage tanks shows a 50% chance that the savings in municipal water use for the toilet will exceed 73%. Because the timing of showers and toilet flushes is assumed to follow a uniform distribution throughout the day, the calculated tank sizes may be underestimates.