Calculation of the amount of greywater production and demands from the Iraqi government office buildings.

Municipal drinking water supplies are under tremendous pressure worldwide, and one way to mitigate the problems is to reuse wastewater in various places, including reuse of greywater. In this paper, the calculation of the amount of gray water from production, demand, and water supply in government buildings was studied based on the British code for non-potable and reusable purposes WC Flushing and according to the characteristics of the building in terms of installation units, several employees and working hours. The Department of Public Works and Maintenance in the Ministry of Construction, Housing, and Municipalities in Baghdad - Iraq has been selected as a study area because the site of the building is located in an area. Many government departments are affiliated with the same ministry, which leads to an increase in the amount of greywater on the sewage network. This paper aimed to calculate the amount of building gray water required for treatment, which can be predicted before treatment. The amount of greywater production, which is exiting from the hand basin and reused for females and males, is 4.8 and 3.2 L/d/employee, respectively. The amount of greywater demand from Wc flushing for females and males is 12 and 6 L/d/employee, respectively, as it was found that females use more than males because of the frequency-time. This study showed that there is potential to reduce the total demand for drinking water by saving 44% by considering the reuse of greywater. [ABSTRACT FROM AUTHOR]