Over the past 4 decades, the increasing amounts of excess sludge from municipal wastewater treatment plants (WWTPs) represent a challenge toward achieving the sustainability of the drinking water and sanitation sector in Egypt, resulting in a serious environmental pollution due to the uncontrolled use of non-stabilized sludge. Here, we report a comprehensive overview on the current situation of excess sludge production, management, and disposal in Egypt. Owing to the technologies used for wastewater treatment in Egypt that mainly consist of activated sludge based-technologies, about 2.1 million tons of dry solids is produced annually. The majority of WWTPs in Egypt lack proper sludge stabilization facilities, except for the WWTPs in high living standards governorates (e.g., Cairo, Alexandria, and Giza). Therefore, about 85% of the non-stabilized sludge is improperly disposed and directly used for agricultural purposes. Despite the importance of managing the use of non- and/or partially-treated sludge, especially for agricultural purposes, the national legislations for sludge disposal/reuse in Egypt are incomplete and, in practice, they are not reinforced. In order to evaluate the most sustainable scenario for sludge management in Egypt, a qualitative decision-support system (DSS) was used. The DSS framework was refined and estimated, based on several evaluating categories, and used to guide the decision process towards achieving sustainable management of municipal wastewater sludge in Egypt. The results reveals that “sludge-to-energy” through anaerobic digestion is the most sustainable scenario for sludge disposal and management in Egypt. The anaerobic digestion-based technology seems to offer advantages of interest at affordable costs, such as the production of renewable energy, stabilized soil conditioners, and fertilizers for agricultural purposes.

The October 2015 storm in Alexandria led to flooding of historical proportions. Although this October storm was a rare event (≈1:50 year), it could have been predicted at least 1 week in advance. If an appropriate warning system had been in place, measures could have been taken to alleviate its consequences. Therefore, the use of rainfall forecasting in storm water modelling can be one of the first useful and cheap mitigation measures. This forecasting system may further allow employing Anticipatory Water Management. The latter would imply that a large extra retention reservoir would be made available by pumping the water out from lakes of the city (Lake Maryot and Airport Lake) before it rains. Further research will be required to assess the technical and economic aspects of this option. The high variability and uncertainty of rainfall call for a robust and flexible strategy for Alexandria, which considers a portfolio of measures able to absorb the negative consequences of extreme events (designed for exceedance). This strategy should enable the responsible authorities to map out the future of the drainage system across the city over the next two or three decades and to identify the tipping point when upgrading of the existing drainage and irrigation system will be required. It will also provide the required evidence base on which a long-term wastewater and sewerage plan for Alexandria City should be implemented.