Techno-economic and Environmental Implications of the Use of a Closed Loop Water Recycling System in Qatar

Abstract

This paper presents the environmental and economic benefits from the use of potable water from a desalination plant, and treated sewage effluent (TSE) for non-potable reuse, in Lusail, Doha. This newly built city plans to use TSE for a large portion (98 %) of its non-domestic applications instead of discharging TSE to the ocean. It was estimated that about 140,112 m3/d desalinated water will be produced for potable water supply and 93,236 m3/day of TSE will be produced from a sewage treatment plant (STP) for use in district cooling systems and in the irrigation of local landscapes, lawns, and pocket gardens. Less than 2.5 % of water demand for non-domestic applications (i.e. irrigation of lawns for water features) will need to be met by potable water. There are significant sustainability benefits associated with the use of TSE in a water scarce and fast growing region like Qatar. A life cycle assessment analysis has been carried out to determine the greenhouse gas emissions, embodied energy consumption and cost savings associated with the recycling of wastewater in Lusail.