Potential Recovery Assessment of the Embodied Resources in Qatar’s Wastewater

Abstract

Due to the ever-growing demand for natural resources, wastewater is being considered an alternative source of water and potentially other resources. Using Qatar as an example, this study assesses the resources embodied in wastewater and paves the way to combine wastewater treatment with advanced resource recovery (water, energy, nitrogen, phosphorous, added value products) which can turn wastewater management from a major cost into a source of profit. In this sense, wastewater is no longer seen as a problem in need of a solution, rather it is part of the solution to challenges that societies are facing today. Based on estimated quantities of generated urban wastewater and its average composition, mass flow analysis is implemented to explore the maximum availability of major wastewater constituents (solids, organic compounds, nutrients, chloride, alkalinity, sulfide). An assessment analysis reveals that, in Qatar, more than 290,000 metric tons total solids, 77,000 metric tons organic compounds, 6000 metric tons nitrogen, 81,000 metric tons chloride, 2800 metric tons sulfide, and 880 metric tons of phosphorus are embedded in about 176 million m3 of urban wastewater annually. One promising valorization strategy is the implementation of anaerobic digestion with biogas production, and the organic materials contained in Qatar’s wastewater corresponds to more than 27 million m3 of methane (equivalent to an energy content of more than 270 GWh) per year. The results further suggest that the recovery of nitrogen, phosphorus, and sulfide should be given priority.