Water and energy savings from greywater reuse: a modelling scheme using disaggregated consumption data

Abstract

Municipal drinking water supplies are under great stress globally, and one way to mitigate the problems is the reutilization of wastewater in various settings. In this paper, a greywater reuse scheme and the impact of system design and configuration on water and energy savings are investigated. The objective of the paper was to investigate the impact of hydraulic design and performance of a greywater treatment and reuse system on water and energy savings. A simulation model was created based on real, disaggregated water consumption data that predicts the reuse potential. Three scenarios were investigated; (1) greywater collection from the bathroom and reuse for toilet flushing, (2) greywater collection from bathroom sinks and showers, and reuse as hot water for sinks and showers, and (3) a combination of (1) and (2) where greywater collection from bathroom sinks and showers is used for toilet flushing, sinks and shower. The results indicate hot water reductions between 55.6 and 58.2%, while cold water reductions ranged from 5.8 to 30.6%. Reductions in energy for producing hot water between 43.5 and 46.8% were observed. Recommendations per connected user for hydraulic design ranged from 0.033 to 0.1 dm3 min−1, 3 dm3, and 0.7–10 dm3 for treatment capacity, collection and holding tank volume.

Integrating Rainwater Harvesting and Greywater Recycling to Increase Water Efficiency in Office Buildings

“…Besides rainwater harvesting, greywater recycling is the best solution for water scarcity and conservation (Radingoana et al, 2020). Greywater contributes to the largest water-saving in domestic residences as it promotes the preservation of high-quality freshwater, reduces environmental pollutants, and decreases the overall supply cost (Knutsson & Knutsson, 2021). Greywater can be defined as household wastewater that comes from both kitchen and bathroom sinks, showers, or baths and is the discharge from laundry activities where it can be reused, replacing the freshwater for non-potable activities such as toilet flushing and the irrigation of plants (Oh et al, 2018).…”

Modified Rice Husk Waste‐Based Filter for Wastewater Treatment: Pilot Study and Reuse Potential

“…GW reuse offers benefits such as reduced potable water demand and energy savings. However, challenges include the need for appropriate treatment to mitigate health risks and potential environmental concerns arising from inappropriate disposal practices [8–10]. Effective management strategies and regulatory frameworks are crucial to realizing the potential of GW reuse [2, 5, 6].…”

Water Reuse in a Municipal Sports Center

“…The reuse of greywater (water flow originated from showers, hand basins, laundry, dish-washing) can be one of the solutions to achieve one of the major goals of urban sustainability: the water [1][2][3][4] and energy efficiency [5]. It has been estimated that about 41-91% of the domestic water use turns into greywater.…”