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

Mohammad Alsheyab,Sigrid Kusch-Brandt

doi:10.3390/su10093055

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.

Highlights

Production of waste by human activities is unavoidable and a significant part of it ends up as wastewater
By performing a quantitative analysis of wastewater constituents in Qatar, this paper provides a platform for innovation into wastewater resource recovery as it identifies the amounts of potentially recoverable resources and paves the way to investigate how such resources can be recovered, whether by developing new technologies or by adapting and perfecting the existing technologies for the case of Qatar
Comparing the values to the typical levels reported in the literature, the table includes an assessment of whether the reported concentrations indicate that the wastewater is significantly charged with individual constituents

Summary

Introduction

Production of waste by human activities is unavoidable and a significant part of it ends up as wastewater. Symptoms of physical water scarcity include problems of water allocation, environmental degradation such as river contamination, and declining groundwater tables. Symptoms of economic water scarcity include lack of proper infrastructure, lack of human capacity to satisfy the demand for water and inequitable distribution of water, even where infrastructure exists [5]. Solids are divided into two main categories, namely, suspended solids (a portion that is filtered out by a 0.45–1.2 μm filter) and dissolved solids (a portion that passes through the filter) [32] Both the dissolved and suspended solids consist of volatile solids and fixed solids, and these are determined by combustion at 550 ◦C (volatile solids, which represent the organic portion, are combusted at this temperature and fixed solids are not).

Methods

Results

Conclusion