Quantitative analysis of greywater in a residential building

ABSTRACT

As a result of population growth and the expansion of arid regions, finding effective ways to reduce the consumption of potable water is essential. Among the solutions, there is the concept of recycling and reusing water for less noble purposes, such as gardening irrigation and flushing toilets. Knowing the adequate treatment and volume of water storage for these uses is essential, since it makes the system more attractive, reducing the costs involved. This article aimed to quantify the volume of greywater consumed by a residential building system, whose use is exclusively dedicated to flushing toilets and gardening irrigation. The research used information on drinking water consumption, as well as the installation of a device capable of providing instantaneous volume variation in gray water reservoirs. From the volumes and resident population, it was possible to determine the quantities of gray water produced and consumed in irrigation and discharge in the enterprise, in addition to the per capita consumption of gray water. The average consumption of greywater was separated according to its uses, being 25.3 L. nhab^-1.day^-1 for flushing and 13.05 L.inhab^-1.day^-1 for irrigation. With these values, the required optimal storage volume has been reduced up to 10 times. In the course of the work, were introduced appropriate criteria for calculating the flow rates of the treatment systems and the ideal reservoir volumes, which can be beacons of comprehensive research.

Keywords:
greywater reuse; daily greywater demand; stored greywater