Green roofs are acknowledged to minimize urban heat island effects, enhance biodiversity, reduce carbon footprint and greenhouse gas emissions, provide hydraulic benefits for stormwater management, and improve the overall environmental sustainability. In arid regions, rainfall is not abundant, as such, the conventional rain fed green roof systems are not applicable. Consequently, a concept of greywater fed green roof system was developed and investigated. Four prototypes of green roofs planted with the canary reed grass, two intensive and two extensive systems, were constructed and irrigated by greywater. Changes of greywater quality in the green roof effluents were monitored. Outcomes of the study revealed that the intensive green roof system performed well, which is attributable to their higher depth of soil media. The performance of green roofs in improving greywater quality was found influenced by the hydraulic retention time. The treated greywater from the green roofs meet the local irrigation water quality standards and can be reused for irrigation to amenity plantations or outdoor non-potable end-uses.
This was presented as a poster